SLEVE'L I.I A

Technical Paper 334

c VEHICLE IDENTIFICATION USING THE ACOUSTIC

SENSOR: TRAINING, SENSING CONCEPTS,

* AND BANDWIDTH

Harold Martinek

Army Research Institute fo," the Behavioral and Social Sciences

and

Sterling Pilette and Bill Biggs

* •HRB-Singer, hic.

C-,)

___ BATTLEFIELD INFORMATION SYSTEMS TECHNICAL AREA

LAr T%

DDC D 2 -

B

U.S..Army

Research Institute for the Behavioral and Social Sciences

September 1978

Aoproved mr publ ic ( I. s: 7iimi,1d. ,hu ,n ,
U. S. ARMY RESEARCH INSTITUTE

FOR THE BEHAVIORAL AND SOCIAL SCIENCES

A Field Operating Agency under the Jurisdiction of the

Deputy Chief of Staff for Personnel

WILLIAM L. HAUSER

JOSEPH ZEII)NER Colonel, US Army Technical [Drector Commander

Research accomplished under conc. ,ict

to the Department of the Army

HRB-Singer, Inc.

NOTICES

DISTRIBUTION Primary distribution of this report hot been made by ARI Pleea address correspondence *

concerning distribution of reports to U S Army Research Institute for the Behavioral and Social Sciences,

ATTN PERI.P, 5001 Eisenhowat Avenue. Alexandrria. Virginia 22333

FINAL l.iPSITION . This report may he destroyed when it is no longer needed. Pleae" do not return it to

the U S. Army Research Institute for the Behavioral end Social Sciences.

QJ" The findings in this report are not to be construed as an official Deportment of thi Army position,

unleet so designated by other authoriaed documents.
Unclassified

SECURITY CLASSIFICATION OF THIS PAGE (When DPE. Itnteod)_

T PAGE READ INSTRUCTIONS REPORT DOCUS..U IATIIf PAGEBEFORE COMPLETING FORM

1. REPORT NUMBER Q OUY-.AC-ZZAL214 NO. 3 RECIPIENT'S CATALOG NUMBER

Technical Paper 334 r -) - , , ,

4. TLE(and.... ... . .. . .. .--- 0 COVERED

..EHICLE, DENTIFCATION USING THE 4COUSTIC Interim ýepi t' II CEPJun 76 - M'ay 7•

;ENSOR: TRAINING, SENSING CONCEPTS, AND S/ JERuORMING OMRay E7RT NUMBER

BANDWIDTH _ _ _ _ _ __........_

- __" ___-------..... .... .____.... __-_-. _ S. CONTRACT OR GRANT NUMIjiERIs

:'I Harold/Martinek. .jijlSterling/Pilette and 76C034

Bill,Biggs tAHOl9-7- --. ',D 

S. PERFORMING ORGANIZATION NAME AND ADDRESS I0. PROGRAI ELEMENT, PROJECT. TASK AREA & WORK UNIT NUMBERS

HRB-Singer, Inc. / / Q... ..........

P.O. Box 60 / 2Q763743A77,

Science Park State College, PA 16601 - .....

11. CONTROLLING OFFICE NAME AND ADDRESS " 12 REPORTA1 . 1 --.

U.S. Army Intelligence Center and School 7/ Sep*NM "978Q

Fort Huachuca, AZ ( / --- 6PAGES NUMER O 

___ 60

14. MONITORING AGENCY NAME A AODRESS(It d*ierent from, Controlling Office) I5. SECURITY CLASS. (of this report)

U.S. Army Research Institute for the Behavioral

and Social Sciences Unclassified

5001 Eisenhower Avenue, Alexandria, VA 22333 Iil. OECLAsSIFICATION/DOWNGRADING

SCHEDULE -_

IS. OISYRI@UTION STATEMF.NT (of this Report)

Approved for public release; distribution unlimited.

17. DISTRIBUTION STATEMENT (of the batr&cl eanteeed In Block 20. It different from Report)

IS. SUPPLEMENTARY NOTES

iS. KEY WORDS (Continue on reverse aids it neceemary and Identify by block number)

Unattended ground sensor Training

Remote sensor Bandwidth

Acoustic sensor Sensing concepts

Surveillance Operator performance

Target acquisition

'•, 210 AuISTrIACT (Continle en rovere* *IM If teceuuy d Icaitify by block miimbet)

S.. Experiments were designed (1) to develop and validate a training program

for using the acoustic sensor to identify vehicles in convoy; (2) to provide

estimates of operator performance in identifying vehicles using the acoustic

sensor; and (3) to investigate the effect of different sensing concepts and

bandwidths on the operator's ability to identify vehicles.

Following an orientation and procedure training, 18 school-trained, unattended ground sensor (UGS) operators were tested in their ability to

It .O I

DO IJA 1,1473 EDITION OF I NO0V $5 IS oPSI;TEl

S• ,:• lln o,,',OOFMO,,,,,••.•7,Unclassified • • •

S..d \•j jac0ISCU0IT CLASSINCAlMN OF TNIS PAGE (Whe-Dateta Entered)

y-1
Unclassified

"SECURITY CLASSIFICATION OF THIS PAE(e Date Enterd)

20. (Continued)

identify military vehicles in conoys. Magnetic tape recordings simulated

use of the acoustic remote sensor in the field. Two sensing concepts were

incorporated--continuous, wherein the operator monitors the entife convoy,

and intermittent, wherein the operator hears each vehicle in the convoy for

4 seconds.

Operators then received vehicle recognition training that u.3ed concepts

of immediate feedback, self-scoring, paired comparisons, and practice. Following this training, the operators were retested to measure the effects of

the training. An exploratory study compared operator performance using three

bandwidths: 50-1500 cps, 50-2000 .7ps (presently used), and 50-4000 cps.

Operators varied widely in ability to identify individual vehicles in

convoys. The best operator reported twice as many correct identifications

as did the poorest operator, under some conditions. -

The intermittent type of sensor was superior in vehicle identification

to the continuous. Both are superior in information potential to the current

operational sensor, the Audio Add-On Unit.

The training package substantially improved operator performance. Operator reports were evaluated using five levels of classification detail. In

terms of exact vehicle identification, operator performance rose from 27% to

40%. When vehicles were categorized into light wheeled, heavy wheeled, APC's,

and tanks, operator performance rone from 32% to 43%. When vehicles were

cateqorized into wheeled vehicles, APC's, and tanks, operator peeformance rose from 53% to 67%. When vehicles were categorized into wheeled and tracked

vehicles, operator performance rose from 68% to 78.5%. The exploratory study

of bandwidth indicates that the 2000 cps is significantly better than the

1500 cps for vehicle identification. There is no significant difference in

operator performance between 2000 (.ps and 4000 cps.

If field requirements permit, only those operators having good sound

recognition ability (about the upper 50%) should monitor acoustic sensors.

The training package should be sent to field units for periodic refresher

training and used at USAICS for UGS training. The intermittent type of sensor was significantly better than the continuous, but both should be considered for use in REMBASS. The exploratory study on bandwidth indicates that

the 50-2000-cps range currently used by the Army is adequate.

;;h 0

UNANN01,NCro

By....

Dis' ,:' U. SpieIl

Unclassified -

SECURITY CLASSIFICATION OF THIS PAGE('en Datd Entered)

iI
Technical Paper 334

VEHICLE IDENTIFICATION USING THE ACOUSTIC

SENSOR: TRAINING, SENSING CONCEPTS,

AND BANDWIDTH

Harold Martinek

Army R-earch Institute for the Behavioral and Social Sciences

and

Sterling Pilette and Bill Biggs

HRB.SIn -r, Inc.

BATTLEFIELD INFORMATION SYSTEMS TECHNICAL AREA

Submitted as complete and Approved By:

technically accurate, by: Edgar M. Johnson A.H. Birnbaum, Acting Director

Technical Area Chief ORGANIZATIONS AND SYSTEMS

RESEARCH LABORATORY

Jos, ph Zeidner

TECHNICAL DIRECTOR

U.S. ARMY RESEARCH INSTITUTE FOR THE BEHAVIORAL AND SOCIAL SCIENCES

5001 Eisenhowcr Avenue, Alexandria, Virginia 22333

Office, Deputy Chief of Staff for Personnel

Department of the Army

September 1978

Army Project Number Intelligence Systems

20763743A774

rI

1'

iI

L..c L ... z.u ,a&tr... g~.fi;C ,, k.- - -
ARI Research Reports and Technical Papers are intended for sponsors of

R&D tasks and other research and military agencies. Any findings ready for

implementation at the time of publication1 are -)resented in the latter part of

the Brief. Upon completit-, of a major phase of the task, formal recommenda•.ins for official action norniailv are conveyed to appropriate military

agencies by briefing or Disposition Form.

J

"* I

!¶

I.

- - .t-- - - - -
FOREWORD

The Battlefield Information Systems Technical Area of the Army Research Institute (ARI) is concerned with the demands of the future battlefield for increased man-machine complexity to acquire, transmit,

process, disseminate, and utilize information. The research focuses on

the interface problems and interactions within command and control cen- ters and concerns such areas as topographic products and procedures,

tactical symbology, information management, user-oriented systems, staff

operations and procedures, and sensor systems incegration and utilization.

Of special interest is the problem of human factors in the presentation and interpretation of surveillance and target acquisition information. One relatively new source of intelligence information is remote monitoring of the battlefield, using seismic. acoustic, and magnetic

unattended ground sensors (UGS). When enemy ýersonnel or vehicle movement activates these remote sensors, a monitor display located behind

our lines indicates the activity. The operator can derive from this

display not only the enemy's presence but also such information as direction and speed of convoys and personnel, number of vehicles .n a convoy,

and convoy composition--e.g., armored versus wheeled vehicles.

This publication concerns the development and validation of special

training for the acoustic remote sensor--currently the best unattended

ground sensor for iientification of vehicles. In addition, two new sensing concepts were investigated for future usc in new systems and found

better than present-day concepts. Bandwidth requirements based on operator needs were experimentally defined.

Research on sensor systems integration and utilization is conducted

both in-house and under contract, in response to requirements of Army

Project 2Q763743A774 and to special requirements of the U.S. Army Intelligence Center and School, Fort Huachuca, Ariz.; Project AVID GUARDIAN,

U.S. Army, Europe; and the Remotely Monitored Battlefield Sensor System

Project (REMBASS). Special requirements are contained in Human Resource

Needs 77-320 and 77-170.

~JOSE ZE R

ech ical Director

... Sii~' j....C.~ .tsL
VEHICLE IDENTIFICATION USING THE ACOUSTIC SENSOR: TRAINING, SENSING

CONCEPTS, AND BANDWIDTH

BRIEF

Requirement:J

The experiments were designed to meet the following requirements:

(a) to develop and validate a training program for using the acoustic

sensor to identify vehicles in convoy; (b) to provide estimates of operator performance in identifying vehicles, using the acoustic sensor;

and (c) to investigate the effect of different sensing concepts and

bandwidth modifications on the operator's ability to identify vehicles.

Procedure:

Following orientation and procedure training, 18 school-trained

operators of unattended ground sensors (UGS) were tested on their ability

to identify military vehicles in convoys. Magnetic tape recordings simulating use of the acoustic remote sensor in the field were used. The

taped simulation was developed from recordings collected in the field

during maneuvers of armored and motorized infantry units. Incorporated

in the test tapes in a counterbalanced arrangement were two acoustic

sensing concepts, "continuous" and "intermittent." In the continuous

mode, operators hear the entire convoy as it passes the microphone. In

seoinds, iten mode, they hear each vehicle for a period of only 4

secodswith 2 seconds of sile-ice between each vehicle. Seven vehicle

types were involved--jeeps, gamma goats, 21⁄2-ton trucks, S-ton trucks,

10-ton trucks, armored personnel carriers, and tanks.

The operators then received vehicle recognition training which

used immediate feedback, self-scoring, paired comparisons, and practice.

After the training, the operators wereŽ retested to measure its effects.

An exploratory study was then conducted to compare operator performance

when different bandwidths were used--50-l500 cycles per second (cps),

50-2000 cps (now in use) , and 50-4000 cps.

V Findings:

The training package developed increased operator vehicle identification performance by 46% to 16%, depending on the level of target

detail required.
An increase of 6% to 10% in veh le idet -. Lion can be achieved

by using the intcrmittent type of * sor rather tihai the continuous.

A saving of 33% in battery life wou.' also result. Either type of sensor has a greater information potential than the present-day Audio

Add-On Unit.

An increase of 13% in vehicle identification can be achieved by

using the top third of operators selected on their ability to interpret

acoustic signals, as measured by the initial test in this exercise.

The 50-2000-cps bandwidth currently used by the Army for the remote

sensor was better than 50-1500 and as good as 50-4000 cps for vehicle identification purposes.

Utilization of Findings:

The self-administrable training tape should be used at the U.S. Army Intelligence Center and School for UGS operator training and in

field units for periodic refresher training.

Depending on field requirements, the remote sensor platoon leader

should selectively assign operators on the basis of their capabilities.

Both the intermittent type and the continuous type of sensor should be

considered for use in the Remotely Monitored Battlefield Sensor System

(REIiBASS).

The bandwidth currently used by the Army for the acoustic remote

sensor is adequate.

V I

V I
VEHICLE IDENTIFICATION USING THE ACOUSTIC SENSOR: TRAINING, SENSING

CONCEPTS, AND BANDWIDTH

CONTENTS

Page

INTRODUCTION .......................... ........................... 1

Specific Objectives .................... ...................... 3

THE TRAINING PACKAGE ...................... ....................... 3

METHOD OF INVESTIGATION .................... ..................... 4

Population and Sample .................... ..................... 4

Apparatus .......................... ........................... 5

Independent Variables .................... ..................... 5

Dependent Variables ....................... ................... 6

Statistical Design--Training ................ ................. 7

Statistical Design---Bandwidth Experiment ......... ........... 7

Procedure ...................... ... ............................ 7

Content of Scenarios ................... ..................... 10

Scoring Criteria ................... ....................... 12

RESULTS AND DISCUSSION ................ ...................... 14

The 7-Target Category .............. ..................... 14

The 5-Target Category .............. ..................... 18

The 3-Target Category .............. ..................... 20

The 2-Target Category .............. ..................... 22

The 1-Target Cate-ory .............. ..................... 22

Field Selection of Operators ........... ................. 25

Tho Bandwidth Study ................ ...................... 25

SUMMARY OF RESULTS AND FIELD IMPLICATIONS ....... ............ 26

J

APPENDIX A. Facilitator Guide ............ .................. 29

B. Practice Effects ............. .................. 57

DISTRIBUTION ...................... ........................... 59
5I

LIST OF TABLES

Table 1. Target classification categories . ........... 6

2. Experimental design--training study ........ .......... 8

3. Experimental design--bandwidth experiment .... ....... 8

4. Schedule of administration ........... ............... 9

5. Composition of convoys on tUe 50-2000-cps

scenario test tapes .......... .................. .. 11

6. Composition of convoys for training .... .......... .. 13

71. Analysis of variance of correct 7-target

category identification .......... ................ .. 15

8. Mean percent correct identification for

the 7-target category .......... ................. .. 16

9. Mean percent correct 7-ta-get identification

by target type and pretest-posttest .... .......... .. 18

10. Mean percent correct identification for

the 5-target cateqory .......... ................. .. 19

11. Mean percent correct 5-target identification by

target category and pretest/posttest .... .......... .. 20

12. Mean percent correct identification for the

3-target category ............ ................... .. 21

13. Mean percent correct identification for the

2-target category ............ ................... .. 23

14. Mean percent target detection for the

1-target category ............ ................... .. 24

15. Pretest/posttest comparisons of operators

grouped on the basis of pretest performance .. ...... .. 26

B-1. Odd/even analysis of practice effect for

7-target categoiy ............ ................... .. 58

B-2. Mean percent correct identification for the

7-target category ............ ................... .. 58
VEHICLE IDENTIFICATION USING THE ACOUSTLC SENSOR:

TRAINING, SENSING CONCEPTS, AND BAWDWIDTH

INTRODUCTION

The Remotely Monitored Battlefield Sensor System (REMBASS) program

is evidence of the Army's commitment to development of an advanced unattended ground sensor (UGS) system for the battlefield of the future.

The acoustic sensor, among those now used by the Army, will play an important role in the future. With human interpretation, the acoustic

sensor is the best target identification system currently in the UGS

inventory. Although this sensor was originally developed for monitoring jungle trails, a promising application is the detailed monitoring

of convoy acti!vity in any theater of operations. The North American

Treaty Organization's Avid Guardian program has recently completed a

series of tests to investigate applications of acoustic sensors in monitoring convoys in Europe.

The current operational acoustic sensors are the audio add-on unit

(AAU), the hand-emplaced commandable (HEC) microphone, and the commandable microphone (COMMIKE).l The AAU is a noncommandable sensor slaved

to the MINISID III. The AAU transmits 15 seconds of audio after three

seismic activations have occurred within a 28-second time period. There

is a minimum 20-second dead period between the 15-second transmissions.

During continuous target activity such as with a convoy, the 15-second

transmission time is not long enough to listen to the whole convoy, and

the 20-second dead period yields no information. Other things being

equal, this dead time may cause a substantial loss of information concerning the composition of a convoy. The HEC is an acoustic sensor

that will transmit audio for 1.25, 5, 10, or 20 seconds upon operator

command. The audio transmission time is preset by programing the code

plug. The air-dropped version of this sensor, the COMMIKE, u-es parachute deployment for canopy hang-up.

Both the UEC and the COMMIKE offer more flexibility than the AAU,

in that the audio transmission is under operator control. The disadvantage is that frequently the operator must command these sensors from

a remote location, using the preset transmission time. Among the three,

the AAU is the most widely used acoustic sensor in the Army today.

USA Unattended Ground Sensor Devices (ST-30-20-l). The United States

Army Combat Surveillance and Electronic Warfare (USACSEW) School, Fort

Huachuca, Ariz. Revised Edition, April 1973.
Research and development efforts to improve the capability of the

acoustic sensor have been principally under the aegis of the REMBASS

project.2 In addition to including an advanced version of the tAU,

REMBASS has beer. experimenting with putting more of the decisionmaking

(analysis and classification) function of the UGS operator into engineering technology by using an acoustic spectrum analyzer to classify

targets as either wheeled vehicles, tracked vehicles, or personnel.

Despite significant research and development expenditures to improve hardware capability, very little has been spent to upgrade the

operator's analysis potential. The need for training to improve operator performance is recognized by many, including UGS field units, the

United States Army Intelligence Center and School (USAICS), and Project

Avid Guarrian. Army personnel in the field have used acoustic sensors

less extensively than seismic sensors because of many factors, including

lack of equipment. Thus, once assigned to the field, operators typically

do iot have the opportunity to maintain or upgrade their skill levels.

In adlition, time restraints at the UGS school limit the amount of sound

recognition training that can be provi.ded.

several approaches to new design concepts have been advanced to

improve the potential for obtaining information by monitoring convoys.

One such approach is to have the sensor provide continuous audio transmission as a convoy passes. Such a sensor is automatically turned on

and off by a seismic sensor much as the AAU is now activated. A second

approach is to have the sensor provide audio transmission for 4 seconds

when each vehicle in the convoy is closest to the sensor. Such a sensor

could be automatically triggered by a line sensor. Because the aidio is

transmitted intermittently, this method saves 33% of the battery life as

compared to the continuous sensor. Both the continuous and intermittent

sensors have the potential of providing 100% of availanle convoy information as opposed to the current AAU system, from which the information

potential is only about 50%. If operators could distinguish between the

vehicles in aggressor convoys and identify them, the field commander

would have a significant improvement in his intelligence-gathering

system.

The frequency ranqe (bandwidth) of the signal transmission is another variation which may have an impact on operator performance and

perhaps on sensor design. The acoustic sensor that REMBASS is developing uses the same frequency range--50-2000 cps--as does the AAU. A

systematic operator performance test is needed to investigate the user

(operator) requirements for bandwidth. A narrower band (50-1500 cps)

may provide the same information, and a wider band (50-4000 cps) may

provide increased information.

2 HQ, Department of the Army, REMBASS Specification-004, November 1975,

pp. 1-8.

2
Specific Objectives

The experiments were conducted to (a) obtain an estimate of the

current level of UGS operators' (MOS 17M) ability to identify individual vehicles traveling in convoys, (b) develop and validate a training program for improving the operators' ability to identify vehicles,

(c) compare the continuous and intermittent sensor concepts, ind (d) explore the relative effectiveness of three signal bandwidti3--50-1500

cps, 50-2000 cps, and 50-4000 cps.

THE TRAINING PACKAGE

The training package was developed to familiarize the operators

with the various vehicle sounds for both continuous and intermittent

sensor types. Each of the two major sections, Continuous Sound Recognition Training and Intermictent Sound Recognition Training, was further divided into the following five parts.

Part I -. Practice convoys with feedback

Part II - Paired comparison of all vehicles (fast speed)

Part III - Practice convoys with feedback

Part IV - Paired comparison of all vehicles (slow speed)

Part V - Repeat test of convoys 1, 2, 3, and 4 with self-scoring.

The complete training package is presented in Appendix A, Facilitator Guide. The entire sensor training program was recorded on tape

and could be used as a self- or a group-administrable package. Training on the intermittent sensor was given first. Training on the two

sensor types was generally similar. (Differences are noted where applicable.) For both types, Part I involved a short instructional briefing, followed by a two-convoy exerci:;e in which the operators identified the vehicles. Feedback was provided to the operators by giving

them the correct vehicle identification. The operators recorded the

vehicle names on their target logs so that they could score their interpretations. In addition to motivating the operators, these scores

were later used by the facilitators to check learning progress informally.

For the intermittent sensor, the operators analyzed the same convoys a second time, with immediate feedback to assist learning. This

Lime they identified the vehicles mentally as they heard them, without

filling in a target log, and were given the identity of the vehicle immediately after its presentation. After everyone understood this procedure, the convoys with feedback were replayed for additional practice.

In the case of the continuous sensor, this method could not be

used. Instead, the operators were given the same convoys to analyze

again as they observed their target logs with the correct identifications marked on them. As the convoys were replayed, a short tone signaled when each vehicle was at closest-point-of-approach (CPA) to the

3
sensor. This procedure was used in the continuous case to teach the

operators to detect vehicles on the basis of variations in loudness.

As with the intermittent sensor, the procedure was -epeated for additional practice.

Part II for both sensor types involved a comparison of the sound

of one vehicle with that of another immediately following. For each

paired comparison, the vehicle identities were given before the sounds.

Each of the target types (vehicles) was compared with every other target type for a total of 21 paired comparisons. One additional comparison was made involving an M60 tank and a Sheridan tank. All target

vehicles were traveling in the fast condition--about 40 kilometers per

hour (kmph) or 24 miles per hour (mph). This exercise was designed to

help the operators remember how the vehicles sound in relation to one

another.

Part III for both sensor types involved the same procedures as in

Part I, except that two different convoys were used. This exercise

gave the operators practice on the same vehicle types but with different individual vehicles and with different combinations and variations

in signal/noise ratio and loudness.

Part IV for both sensor types involved the same matched-pairs procedure as Part II. However, the target vehicles were traveling slower

than in Part II, about 20 kmph or 12 mph. This exercise was designed

to give operators a chance to compare the sound of one slow-moving vehicle with another, a distinction required because the sound signatures

of vehicles can differ, depending upon speed.

Part V for both sensors involved a replay of the four convoys that

the operators had previously worked with. The convoys were administered

in random sequence, and the operators again reported vehicle types on

the target logs. Operators were not told that these convoys were the

same as those they had just trained with. Feedback was then given,

and the operators were asked to score themselves. This procedure not

only gave the operators additional practice and motivation, but also

gave the facilitators an indication of operator progress.

METHOD OF INVESTIGATION

Populati •n and Sample

The population of concern is the Army-enlisted UGS operators (MOS

17M20) who have been trained at the USAICS. Eighteen UGS operators of the Remote Sensor Platoon of the 101st Airborne Division participated

in the experiments.

4
Apparatus

Two Uher tape recorders (Model 4400 and Model 4000), a f6eder box,

11 headsets, and miscellaneous equipment were used to simulate use of

the acoustic sensor in the field. 3 This equipment enabled 11 persons

(10 operato.rs and 1 facilitator) to listen to the training and test

scenarios at the same intensity level. The Uher 4000 was used for

training and the Uher 4400 for testing. The frequency response of the

Uhers was essentially flat from 50 cps to about 4500 cps at the tape

speed (1-7/8 inches per second) used.

Independent Variables

Pretest/Posttest. The effectiveness of training was assessed by

a pretest/posttest design. The operators were tested first to determine their baseline performance prior to training and were tested again

after training to determine improvement.

Sensor Type. The sensor types tested were the continuous sensor

and the intermittent sensor, reflecting differences in concepts of

sensing and transmitting the audio signal to the operator.

Scenario. The scenarios w~re constructed of the taped sounds of

convoys simulating sounds the operator would monitor in the field. Two

scenarios (A and B) each represented two battalions. Each battalion

contained 5 convoys with about 9 vehicles per convoy, for a total of

10 convoys per scenario. The scenarios were roughly matched on the

basis of convoy type (wheeled, tracked, and mixed), convoy speed, and

vehicle types, and were presented in the same order for beth the pretest and the posttest.

Period (Sequential Effects). Each scenario was presented twice

in the pretest and twice in the posttest, once in each case for the

continuous sensor and once for the intermittent sensor. Operator performance was analyzed mainly to assess practice effects.

Target Type. Seven target types were used: jeep (JP), gamma

goat (GG), 2-s-ton truck (2-1⁄2T), 5-ton truck (5T), 10-ton truck (10T),

armored personnel carrier (APC), and tank (TNK).

Groups. Nine operators were assigned on an availability basis

to each of two groups.

3The commercial designation is used for purposes of specific identification of the equipment and does not constitute endorsement by the

Army Research Institute or by the Army.

5I
Bandwidth. Three frequency ranges were compared in the exploratory

stuidy of bandwidth: 50-1500 cps, 50-2%00 cps, and 50-4000 cps.

Dependent Variables

Percent Detection. This variable was the percentage of vehicles detected (number of vehicles reported divided by the number presented).

Percent Identification. This variable was defined as the percentage

cf vehicles correctly identified (number correct divided by the number presented). The first analysis used the seven vehicle types listed under

Target Type, hereafter referred to as the 7-target category. Operators'

reports were also scored using the 5-target, 3-target, and 2-target categories shown in Table 1. Use of the 1-target category yielded the measure

of percentage of vehicles detected.

Table 1

Target Classification Categories

Categories Targets

7-target JP GG 2-1⁄2T 5T 10T APC TNK

5-target Light Medium Heavy

wheeled wheeled wheeled APC TrNK

3-target Light wheeled Heavy Tracked

wheeled

2-target Wheeled Tracked

1-target Vehicle detections

6
Statistical Design--Training

In the training experiment, a pretest/posttest design with the same

two scenarios for each test was used. Each scenario contained a 2 x 2 x 2

Latin square nested within each cell of the factorial. 4 A schematic presentation of this design is given in Table 2. Because Scenario A always

preceded Scenario B, scenario effects were confounded with Lime effects

(motivational changes, learning, etc.). However, this effecL is of little

consequence because the scenario was included in the design for control

purposes only. A more basic weakness in the design is a possible confounding of practice and training. Period effects in t e main analyses

and a comparison across battalions within scenarios were used to check

on practice ef'ects. A consistent scenario effect also could indicate

practice effects.

Statistical Design--Bandwidth Experiment

Table 3 gives a schematic presentation of the design for an exploratory study of bandwidth. Three levels of bandwidth (50-1500 cps, 50-2000

cps, and 50-4000 cps) were compared for the continuous sensor case. Statistical significance was assessed using t tests. Data collected under

the posttest condition of the training experiment were used for the 50-

2000-cps bandwidth condition. Extensive training was not provided in this

exploratory study. Training was given only to familiarize the operators

with vehicle sounds under the different frequency ranges. The 50-1500

cps and 50-4000-cps training consisted of a paired-vehicle exercise for

both fast and slow convoys. This training was administered after the

posttest of the training experiment using the same experimental procedures.

Procedure

Each operator participated for 3 days (as shown in Table 4), receiving the orientation briefing and the procedure familiarization (Appendix A)

during Day 1. The orientation briefing dealt with the purpose of the study, and the procedure training falmiliarized the operators with the methods for

data collection, both pretest and posttest, and also served as a warmup

period. After the test procedure training, the operators were given the

pretest (Scenarios A and B).

Day 2 consisted of the training discussed previously, followed by

the posttest. Because of a scheduling problem, half the posttest (Scenario A) was administered during Day 2 and the other half (Scenario B)

during Day 3. The bandwidth training then followed (Day 3), and the

operators were given the post/posttest, using part of Scenarios A and B.

4Winer, B. J. Statistical Principles in Experimental Design. New York:

McGraw-Hill Book Company, Inc., 1962.

7-.
Table 2

Experimental Design--Training Study

Operator Scenario A Scenariu B

groups ist period 2d period 1st period 2d period

Pretest (50-2000 cps)

Group 1

(n = 9) Continuous Intermittent Continuous Intermittent

Group 2

(n = 9) Intermittent Continuous Intermittent Continuous

Posttest (50-2000 cps)

Group j

(n - 9) Continuous Intermittent Continuous Intermittent

Group 2

(n = 9) Intermittent Continuous Intermittent Continuous

Table 3

Experimental Design--Bandwidth Experiment

5'0-2000 cps SO-1500 cps 50-4000 cps

Posttest data Post/posttest data Post/posttest data

5 convoys Same 5 convoys Same 5 convoys

continuous sensor Continuous sensor Continuous sensor

i8
Table 4

Schedule of Administration

Day 1 AM--Group 1 Orientation Briefing

(9 operators) Test Procedure Familiarization

50-2000 cps Pretest (Scenarios A and B)

PM--Group 2 Orientatioa Briefing

(9 operators) Test Procedure Familiarization

50-2000 cps Pretest (Scenarios A and B)

Day 2 AM--Group 1 50-2000 cps Training

Posttest (Scenario A)

PM--Group 2 50-2000 cps Training

Posttest (Scenario A)

Day 3 AM--Group 1 50-2000 cps Posttest (Scenario B)

50-1500 cps Training Bandwidth Study

50-1500 cps Post/posttest

50-4000 cps Training

50-4000 cps Post/posttest

PM--Group 2 50-2000 cps Posttest (Scenario B)

50-4000 cps Training Bandwidth Study

50-4000 cps Post/posttest

50-1500 cps Training

50-1500 cps Post/posttest

9
Content of Scenarios

Test and training scenarios were constructed, making use of sound

signatures taken from magnetic tape recordings collected during a field

exercise at Fort Hood, Tex. The exercise consisted of armored and

mechanized infantry battalion convoys on both hard-surfaced roads and

tank trails, at speeds varying between 5 mph and 40 mph. The acoustic

tapes were analyzed to select and categorize convoys on the basis of convoy type (wheeled, tracked, and mixed), speed (fast, slow), target type

(JP, GG, 2-1⁄2T, 5T, 10T, APC, TNK), and confidence in ground truth data.

The signal-to-noise ratio of the original field tapes was 36 decibels (dB), a figure obtained by comparing the highest signal strength

recorded of a tank to the signal strength recorded during a perl.od of no

target activity. The quality of the recording equipment used ± ,r reproducing a master tape from the field tapes and subsequent reproductions

was such that essentially no noise was introduced.

A master tape composed of the 30 convoys in the continuous sensing

mode was made, with the bandwidth clipped to 50-2000 cps (to correspond

to the operational bandwidth); another master tape of 9 of these convoys

in the continuous mode was made at 50-5000 cps.

Convoys for the test and training tapes were selected from the convoys on each master tape. From the 50-2000-cps master tape, 20 convoys

were selected fo•. the 50-2000 cps test tape, and 7 for the 50-2000-cps

training tape. Out of the nine convoys of the 50-5000-cps master tape,

five were selected for dual use in the training and bandwidth experiments

and were reduced in bandwidth as necessary. Composition of the test tapes

is shown in Table 5. During the taping of the 50-2000-cps test tape, the

continuous sensor scenario was taped directly from the master tape. This

tape was then used with an in-line timer to reproduce the tape for the

intermittent condition and to insure a 4-second target signal with about

2 seconds of silence between vehicles.

10

5: io

!I
(d ( D "NU) ) 0 CIDOD ) o 4 tn Ln 0 C-I r rI - - r- 0 D %D 4 N D

41O ('L - 0 ' 'A.4 (rO' LA 4r- OO - l 04 OO AO I W C.0 r

040

UE

E-4

0 t

"r-4 'U r- CN 0

o E-4

C- 44 444-

(U .---- U U(U

co i

o1 d0- C, m 0 n C ,c - r ý )iL

$4*

0 H4

00

0 r11

fd 0
During the taping of the continuous sensor convoys, the individual

vehicle signals were clipped to about 6 seconds in order to better simulate operational conditions. This reduction was necessary, because during

peacetime maneuvers vehicles travel much farther apart than they would in

a wartime road march. Based on estimated traveling intervals and speeds

of aggressor convoys, 5 , 6 it was determined that enemy vehicles travel about

6 seconds apart; that is, ore vehicle would pass the acoustic sensor every 6 seconds. This time separation between vehicles is relatively constant

for day and night travel. During the night, however, both the vehicle

speed and the distance between vehicles are less than during the day. The

time between individual convoys and battalions also was made to correspond

to wartime operation conditions during the taping.

Several of the convoys were also used in the pos'/posttest tape (Table 5). This tape involved the continuous mode only at 50-1500 cps and

at 50-4000 cps but was otherwise identical to that used in the 50-2000

condition. Table 6 describes the seven convoys used in the 50-2000-cps

training tape. A separate training tape was used for the 50-1500-cps and

50-4000-cps conditions.

Scoring Criteria

Operator reports were scored as follows.

Vehicle Detection. If an operator reported a vehicle (by any name) when there was a vehsicle, it was scored as a detection.

Vehicle Identification. Because the operator had only about 6 seconds to recognize and report a vehicle and was required to give an exact

identification (truck or jeep, for example), he sometimes reported fewer

vehicles than were present, especially with the continuouE. sensor. In

case of an omitted target, a flexible scoring strategy was used that allowed maximum credit for vehicles reported out of sequence. Had a more

rigid scoring key been used, a vehicle reported out of sequence might

have been scored as an error.

In practice, depending on field requirements, a combat commander requests information at different levels of detail. Generally, the more

detailed the reported information, the greater the error rate. A combat

commander may prefer very accurate gross information or relatively inaccurate detailed information. For this reason, operator reports were

scored using different categories of target identification, each successively more detailed.

Military Publishing House. Combat Actions at Night. Moscow, DIA. 1970.

6Field Manual FM 30-102. Handbook on Aggressor. HQ, Department of the

Army. June 1976, pp. 20-23.

12

>I
UU c 0 0 L

0 41

C) E- 0 0 0 4 0 0 H

4) Ln

u, H ~ H 0 0 L

0 0 0 0 0 H 0

C),

p4-

0

0 4

W 0 0 H 0 0 H

W HA D4) 0) W D 1

H U)

ol 4 C ; 4 1 ý r 244

".4-

4.) to) :3 : .) 4) 0

4.4

24 4- k D U

".E13.
For the l--target (detection) category, if the operator responded

when there wau a vehicle, regardless of vehicle type, it was scored as

a detection.

For the 2-target category, if an operator correctly reported a vehicle as a wheeled vehicle, it was scored as a correct identification

regardless of exact target type. A similar procedure was used for tracked

vehicles.

For the 3-target category, if an operator reported any of the vehicles

under tne light wheeled category (see Table 1), it was scored as a correct

identification. A similar procedure was used for the heavy wheeled and

tracked vehicles.

For the 5-target category, if an operator reported either of the vehicles under the light wheeled category (Table 1), it was scored as a

correct identification. A similar procedure was used for the heavy wheeled

category. For the medium wheeled, APC, and tank targets, credit vas givell

only to exact reports of 2-1/2T, APC, and TNK.

For the 7-target category, credit was given only for exact identification of each vehicle type. The flexible scoring strategy was maintained

throughout all the categories.

RESULTS AND DISCUSSION

Results are presented for each of the five levels of target identification required, stcrting with the most detailed.

The 7-Target Category

An analysis of variance was conducted on the number of correct identifications of the 7-target category (Table 7). The percentages of correct identification averages are presented in Table 8.

The groups' effect and all interactions with groups were nonsignificant, indicating that the two groups of UGS operators were similar in

ability to identify vehicles using the acoustic sensor.

14

I
Table 7

pAnalysis of Variance of Correct 7-Target Category Identification

Significance

Source of variation df 55 ms F level

Between subjects 17 4,835.72 78.03 .26 NSJ

Groups 1 78.03

Subject within groups 16 4,757.69

Within subjects 126 8,368.50

Sensor type 1 240.25 240.25 10.79 .01

Period 1 160.44 160.44 7.21 .05

Residual (1.) 16 356.31 22.27

Scenario x groups 1 42.25 42.25 1.44 NS

Residual (2) 16 470.25 29.39

Pre/post 1 4,203.36 4,203.36 62.39 .01

Pre/post x groups 1 18.77 18.77 .28 NS

Residual (3) 16 1,077.87 67.37

Scenario x pre/post 1 78.03 78.03 5.10 .05

Scenario x pre/post x

groups 1 13.45 13.45 .88 4

Residual (4) 16 244.75 1.30

Sensor type x scenario 1 .30 .30 .91 NS

Period x scenario 1 1.99 1.99 .06 NS

Residual (5) 16 534.63 33.41

Sensor type x pre/posL: 1 4.01 4.01 .16 NS

Period x pre/post 1 61.33 61.33 2.43 NS

Residual (6) 16 404.52 25.28

Sensor type x scenario x

pre/post 1 .00 .00 .00 NS

Period x scenario x

pre/post 1 .03 .03 .00 NS

Residual (7) 16 282.48 17.66

Total 143 13,204.22

15 

*
Table 8

Mean Percent Correct Identification for the 7-Target Category

Se/nsorPretest

Scenario A Scenario B

SensorAverage

Stype Period I Period 2 Period 1 Period 2

Contii•uous Group 1 Group 2 Group 1 Group 2

24% 28% 23% 28% 26%

Intermittent Group 2 Group 1 Group 2 Group 1

28% 32% 26% 29% 29%

Averages 26% 30% 24%' 28% 27% VJ Se/nsorPosttest 1

Scenario A Scenario B

Z~ensorAverage

type Period 1 Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

40% 41% 34% 39% 39%

Intermittent Group 2 Group 1 Group 2 Group 1

44% 40% 40% 36% 40%

Averages 42% 40.5% 37% 37.5% 39%

16
The effect of sensor type (continuous vs. intermittent) was significant. Use of the continuous sensor resulted in an average of 32.1% correct identifications, whereas use of the intermittent sensor resulted in

an averaý f 34.4% correct identifications. Thus, although the opera- tors had only 4 seconds in which to identify a vehicle in the intermittent condition (as compared to 6 seconds in the continuous), they still

correctly identified a greater number of vehicles. The advantage probably

occurred because each vehicle in a convoy in the intermittent condition

is separated by a 2-second silent period and thus is easier to detect

than vehicles in the continuous sensor condition; for the latter condition, the operator must detect the passing of each vehicle by its characteristic changes in intensity and frequency.

The small but significant difference between the two sensor types

(32.1% vs. 34.4%) would seem minimal in the practical sense. However,

in an actual convoy situation in the field, the difference between the

continuous and intermittent sensors would probably be greater because of

the manner of recording under the continuous sensor condition. The convoys recorded in the field were traveling under peacetime maneuver regulations, and the time between vehicles was longer than it would be in

wartime. These 'intervals were shortened appropriately in order to better

simulate operational conditions; in the process, som., recognizable "clicks"

between vehicles were caused when the tape recorder was stopped or started.

Thus, even though there were no distinct silences between vehicle sounds

(as with the intermitten- condition), these clicks (which are artifacts

of the simulation) may have helped operators to discriminate between successive vehicles and may thereby have artificially raised their detection

and identification scores in the continuous sensor condition. The difference would probably be greater in an operational situation.

The statistically significant pretest/posttest effect indicates that

training did enhance operator performance. As shown in Table 8, the pretest average is 27% correct identification and the posttest average is

39%. In other words, the training increased operator performance by 12

percentage points, for a 44% increase in performance.

Period, or order, effect was also statistically significant. Period 1 average is 32% and Period 2 average is 34%, suggesting that practice during the test administration may have contributed to the increase

from pretest to posttest performance. The interaction of period ard pretest/posttest was not significant, indicating that the significant period

effect was distributed over both pretest and posttest. The gain in performance attributable to practice effects is minimal compared to the large

pretest/posttest differences (See Appendix B for additional analyses.)

Thus, the conclusion that training enhanced operator performance appears

valid.

The remaining statistically significant effects are scenario and the

scenario by pretest/posttest interaction. Scenario A resulted in an overall performance average of 35% correct identification, and Scenario B

resulted in 31.5% correct identification. Since Scenario A was presented

17

-L.C
to the subjects first, and Scenario B second, there is no way of knowing

whether the significant scenario effect is due to differences in scenario

difficulty or time effects (e.g., motivation).

The interaction of scenario and pretest/poettest was significant.

The scenarios were similar in performance for the pretest (Scenario A,

28%; Scenario B, 26%) but dissimilar !or the posttest (Scenario A, 42%;

Scenario B, 37%). This result is probably attributable to the necessity for dividing the posttest into two sections and administering the sections

on two different days; this break in continuity may account for the lower

posttest scores on Scenario B.

The results were further analyzed on the basis of target type to

determine the differential effects of training (Table 9). The training

had the greatest impact on jeeps, gamma goats, 10-ton trucks, APC's, and

tanks, and the least effect on 2-1⁄2-ton and 5-ton trucks.

Table 9

Mean P'ercent Correct 7-Target Identification by Target

Type and Pretest-Posttest

Period JP GG 2-1⁄2T 5T 10T APC TNK

Pretest 18 17 26 17 22 29 50

Posttest 28 29 29 20 33 51 60

The 5-Target Category

For the 5-target category, jeeps and gamma goats were combined as

light wheeled vehicles, the 2-1⁄2-ton trucks were considered medium wheeled

vehicles, the 5-ton and 10-ton trucks were grouped as heavy wheeled vehicles, the armored personnel carriers as light tracked, and tanks au heavy

tracked. The results for this category are presented in Table 10.

A statistically significant difference was found between the pretest and posttest results (t = 7.47, df = 17, p > .01). The pretest overall

average was 31.5% identification and the posttest average 45% identification. The percentage increase over pretest performance was 43%.

18

6i

I
Table 10

Mean Percent Correct Identification for the 5-Target Category

Pretest

Scenario A Scenario B

ensor Average

type Period 1 Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

27% 31% 28% 33% 30%

Intermittent Group 2 Group 1 Group 2 Group 1

33% 35% 32% 32% 33%

Averages 30% 33% 30% 33% 31.5%

Posttest

Scenario A Scenario B

/Sensor -Average

type Period 1 Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

44% 45% 39% 44% 43%

Intermittent Group 2 Group 1 Group 2 Group 1

49% 48% 45% 44% 46.5%

Averages 46.5% 46.5% 42% 44% 45%

19
Although an analysis of variance was not conducted, several generalizations can be made. The relationships between the variables are similar

to those in the 7-target category data. Overall, operator performance was

slightly higher because less target detail was required. The difference

between the continuous and intermittent sensors was about the same as with

the 7-target identification level--36% versus 40%, respectively.

The data were further analyzed on the basis of target type (Table 11).

The training had the greatest impact on light wheeled vehicles, APC's, (or

light tracked), and tanks (heavy tracked). The training had least effect

on medium and heavy wheeled vehicles.

Table 11

Mean Percent Correct 5-Target Identification by Target

Category and Pretest/Posttest

Light Medium Heavy Light Heavy

Period wheeled wheeled wheeled tracked tracked

Pretest 28 26 28 29 50

Posttest 42 29 34 51 60

The 3-Target Category

For the 3-target category, the jeeps, gamma goats, and 2-1⁄2-ton

trucks were combined as light wheeled vehicles, the 5-ton and 10-ton

trucks as heavy wheeled vehicles, and the APC and tank as tracl -.d vehicles. Results are presented in Table 12. A t test indicated a statistically significant difference between the pretest and posttest results

(t = 5.77, df = 17, p > .01). The pretest overall average was 53% identification, and the posttest average, 62%.

Overall performance was considerably higA,,.r when operators were required to deal with only three target types than when they had to distinguish between seven or five target types. At the same time, percentage

of improvement due to training declined with the fewer target types: seven targets, 46%; five targets, 43%; and three targets, 18%. Differences between pretest and posttest results were somewhat similar: seven

targets, 13%; five targets, 13%; and three targets, 9%; differences between the continuous and intermittent sensor types also were similar:

2%, 4%, and 5% correct identifications, respectively.

* 20

r
Table 12

Mean Percent Correct Identification for the 3-Target Category

S~Pretest

Z esr Scenario A ScenarioBAvrg j,•nsorAverage

type Period I Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

47% 52% 47% 52% 49.5%

Intermittent Group 2 Group 1 Group 2 Group 1

58% 60% 55% 53% 56.5%

Averages 52.5% 54.5% 51% 52.5% 53%

S~Posttest

ensor Average Period 1 Period 2 Period 1 Period 2 Stype 

Continuous Group 1 Group 2 Group 1 Group 2

62% 61% 55% 62% 60%

Intermittent Group 2 Group 1 Group 2 Group 1

65% 67% 64% 60% 64%

Averages 63.5% 64% 59.5% 61% 62%

21
The results were further analyzed on the basis of target type. The

percentage of correct identifications of light wheeled vehicles increased

through training from 47% to 56%, of heavy wheeled vehicl 3 from 28% to

34%, 4rd of tracked vehicles from 58% to 79%.

An additional 3-target category that may be operationally useful is

wheeled vehicles, APC's, and tanks. Using this breakdown, the pretest

overall average was 53% correct identifiLations and the posttest 67%--

a percentage increase of 26%.

The 2-Target Category j

The results for the 2-target category (wheeled and tracked vehicles)

are presented in Table 13. A t test conducted on these data indicated a

statistically significant difference between the pretest and posttest results (t - 4.83, df - 17, p > .01). The pretest overall average was 68%

correct identifications, and the posttest average, 78.5%. The percentage

increase over pretest performance was 15%.

As expected, perf.rmance substantially increased as the amount of

required target detail was reduced. In some tactical situations, convoy

information in terms of wheeled and tracked vehicles would be completely

satisfactory. The difference between the continuous (69.5%) and intermittent (77%) sensors is consistent with the previous results but slightly

higher. Using the intermittent sensor, the operators identified 11% more

vehicles.

Scenario differences (significance was not tested) apparently reversed directions for the 2-target category: performance on Scenario A

was about 3% less than on Scenario B. This result may reflect the higher

percentage of wheeled vehicles in Scenario B--the scenarios are more difficult when the operator must distinguish among types of wheeled vehicles.

The results were further summarized by target type. The percentage

of correct identifications of wheeled vehicles increased through training

from 67% to 78%, and of tracked vehicles, from 68% to 79%.

The 1-Target Category

The results for the 1-target category (which is the same as detecting and counting the vehicles) are presanted in Table 14. A t test indicated a statistically significant difference between pretest and posttest

results (t - 4.32, df - 17, p > .01). The pretest overall average was

89% detection, and the posttest average, 95%. The percentage of increase i

over pretest performance was 7%.

22

- -'
Table 13

Mean Percent Correct Identification for the 2-Target Category

Pretest

Scenario A Scenario B A

SesrAverage I

Period 1 Period 2 Period 1 Period 2 S

Continuous Group 1 Group 2 Group 1 Group 2

55% 65% 61% 70% 63% I

Intermittent Group 2 Group 1 Group 2 Group 1

72% 69% 81% 68% 72.5%

Averages 63.5% 67% 71% 69% 68%

Posttest

Scenario A Scenario B

/Sensor Average

type Period 1 Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

74% 73% 73% 84% 76%

Intermittent Group 2 Group 1 Group 2 Group 1

78% 82% 86% 77% 81%

Averages 76% 77.5% 79.5% 80.5% 78.5%

23
Table 14

Mean Percent Target Detection for the 1-Target Category

Pretest

Scenario A Scenario B

/ Sesr-Average

type Period 1 Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

81% 85% 85% 88% 85%

Intermittent Group 2 Group 1 Group 2 Group 1

95% 93% 94% 90% 93%

Averages 88% 89% 89% 89% 89%

Posttest

Scenario A Scenario B

Sensor -Average

type Period 1 Period 2 Period 1 Period 2

Continuous Group 1 Group 2 Group 1 Group 2

91% 93% 89% 96% 92%

Intermittent Group 2 Group I Group 2 GrouJp 1

96% 98% 98% 95% 97%

Averages 93.5% 95.5% 93.5% 95.5% 94.5%

V. ~24

.....
Differences between the continuous sensor and intermittent sensor

(89% vezsus 95% detection) were not as large as expected, either with

one category of target or throughout the 7-, 5-, 3-, and 2-target catugories. As explained earlier, the tape recorder "clicks," which were a

necessary evil in building the master tapes, probably cued the operators

as to vehicle sequence and produced overinflated scores for the continuous sensor condition. This difference in target detection largely accounts for the differences found in the identification of ta..gets (target

categories 2 through 7).

Field Selection of Operators

The data were also examined by arranging the operators into three

groups on the basis of pretest performance. The mean percent correct

identifications, differences, and correlation coefficients for pretest

and posttest performance are presented in Table 15. Pretest scores correlated significantly with posttest performance, indicating that a performance test such as the pretest could be used to assign individuals to

the acoustic monitoring task. The increase in performance associated

with using only the top third can be seen in Table 15 for each target

category.

The differences between pretest and posttest performance seem to

indicate that lower ability groups tended to gain more from training for

the easier tasks, i.e., the 2-target and 3-target categories. The groups

seemed to gain equally from tratining for the harder tasks.

The Bandwidth Study

PAn exploratory investigation (five convoys) was made to determine

the effects on operator performance of the use of different frequency

ranges in the continuous sensor condition. The 50-1500-cps and the 50-

4000-cps frequencies were compared with each other and with the currently

used 50-2000-cps range in the 7-target case only. The percent identification averages for the three frequencies are 22% (1500 cps), 29% (2000

cps), and 24% (4000 cps). The t tests were as follows:

1500 cps vs. 2000 cps (t = 2.11, df - 17, p > .05)

1500 cps vs. 4000 cps (t = 1.05, df = 17, NS)

2000 cps vs. 4000 cps (t = 1.46, df -.: 17, NS)

The statistically significant difference between the 1500-cps and 2000-

cps condition indicates that the frequency range currently used by the

Army (50-.2000 cps) should not be reduced. On the other hand, the data

also suggest that the higher frequency range (50-4000 cps) may not result in higher interpretability. These data indicate that the 50-2000-

cps range currently used by the Army is adequate.

25

I
Table 15

Pretest/Posttest Comparisons of Operators Grouped on the Basis

of Pretest Performance

(Percent Correct Identification)

Category Operator group Pretest Posttest Difference Correlation

7-target Upper third 34 47 13

category Middle third 26 36 10 .69*

Lower third 22 34 12

5-target Upper third 39 50 11

category Middlle third 30 46 16 .57**

Lower third 25 39 14

3-target Upper third 61 66 5

category Middle third 52 61 9 .55**

Lower third 45 58 13

2-target Upper third 77 80 3

category Middle third 67 79 12 .57**

T,uwdr third 59 75 14

1-target Upper third 95 96 1

category Middle third 90 94 4 .48**

Lower third 81 93 12

*Significant at .01.

**Significant at .05.

The administration of the bandwidths was counterbalanced for the two

groups, i.e., Group 1 received the 1500-cps bandwidth first, and Group 2

received the 4000-cps bandwidth first. A check on the group averages

shows order effeots as minimal--the results for Group 1 are 24% (1500

cps) and 24% (4000 cps) and the results for Group 2 are 24% (4000 cps) S~and 20% (1500 cps).

SUMMARY OF RESULTS AND FIELD IMPLICATIONS

Several aspects of the current experiment should be considered when

the resultb of this study are used. The continuous sensor results may be

inflated somewhat over what would be obtained in an actual field situation because of tape recorder "clicks" between vehicles, which may have

I 26

V!
acted as cues to the operators. The signal/noise ratio of 36 dB (based

on the signal of the loudest vehicle) may be better than in the usual

sensor conditions and may have inflated performance. On the other hand,

in the process of compiling the test tapes from field-collected tapes,

changes in the dynamic range of signal strsngth may have resulted in

lowered performance. Presenting fast and slow convoys in a random order

rather than as a string of convoys at similar speeds may have lowered

performance.

The scenario material used in these experiments was based on tape

recordings of actual vehicle convoys during field maneuvers and developed

to simulate actual field conditions. The results represent the best estimates to date of what the commander might expect from regularly and

specially trained operators.

If the commander requires that convoy vehicles be reported in detail (7-target category--jeep, gamma goat, 2-1⁄2-ton truck, 5-ton truck,

10-too truck, APC, and tank), he can expect 27% correct identification

before special training and 40% after training, a difference of 33 percentage points and an improvement of 46%. The training results for each

target category arc shown below.

If the commander Today's Operators with Which is a Or an inrequires convoys operators extra training difference crease

reported in will get will get of of

7-target category 27% correct 40% correct 13% 46%

(exact identification)

5-target (light, 32% correct 43% correct 11% 43%

medium, and heavy

wheeled, APC, and

tank)

3-target (tracked and 53% correct 62% correct 9% 18•

light and heavy wheeled

vehicles)

3-target (APC, tank, 53% correct 67% correct 14% 26%

and wheeled vehicles)

2-target (wheeled and 68% correct 78% correct 10% 16%

tracked vehicles)

1-target category 89% correct 95% correct 6% 7%

(counting)

27

4
Based on the results of this study, the trainin3 materials developed

have a significant impact for field use and should be incorporated in

school training and be circulated to UGS units for on-the-job refresher

training. The training is most effective for jeeps, gamma goats, APC's,

and tanks, and least effective for 2-1⁄2-ton trucks, 5-ton trucks, and

10-ton trucks. Units using this training package should enhance the

existing tapes by collecting additional sound signatures of these three

vehicle types. Optimally, sounds of aggressor vehicles should replace

those of U.S. vehicles in the training simulation.

Sound recognition to the level of specific vehicle identification

is a difficult perceptual task. However, operators can be trained to

improve significantly their ability to interpret vehicle sounds, using

either the continuous or the intermittent sensors. When performance was

averaged over all levels of target reporting, operators reported about

10% more information before special training and 6% more after training,

using the intermittent sensor rather than the continuous sensor.

Results show that operators can effect.vely monitor convoys and that

both t&'- continuous and intermittent sensors are superior to the current AAU sc ssor in the amount of information obtained. The continuous and intermittent sensors have 100% information potential, whereas the AAU has

about 50% maximum. The two should be considered for use in REMBASS.

The reseL.ch also shows that operators differ greatly in ability to

identify vehicles using the acoustic sensor. If only those operators

with superior sound-recognition ability were used to perform this task

in field units, a substantial gain in information would result. For

example, if commanders were to routinely assign present-day operators

(not specially trained) to the continuous sensor to identify tracked and

wheeled vehicles, they could expect about 68% of the enemy vehicles to

be properly identified. If they were to us% only the top third of these

operators, then 77% of the enemy vehicles would be properly identified.

Better performance still would be expected if only the intermittent sensor and specially trained operators were used. The better operators can

be identified by means of the test scenarios already developed for this

training program.

In sum, optimal information output can be achieved by using the top

third of specially trained operators and the intermittent type of sensor.

The results of this research indicate that under such conditions, 85%

of tracked and wheeled vehicles can be correctly identified; 72% accuracy

can be achieved under these conditions in identifying three target cateqories--light wheeled, heavy wheeled, and tracked vehicles. Corresponding accuracy for the average, regularly trained operator using the continuous sensor is 63% and 50%, respectively, a difference of 22% in each

case.

28

4
APPENDIX A

FACILITATOR GUIDE

Classroom Needs

1. Tape recorder

2. Feeder box with female plugs (optional) 3. Headset for each operator (optional) 4. Target logs, pencils, etc.

Orientation briefing - about 10 min.Ai

Test Procedure Familiarization - about 40 min. A- 5

Pretest - (10 convoys each)

continuous convoys 1-10 - about 20 min.I

Intermittent convoys 1-10 -about 20 min,

Continuous convoys 11-20 -about 22 min.

Intermittent convoys 11-20 - about 22 min.

Training.- 50-2000 cps baindwidthI

Part 1 - Intermittent Sound (Voice Feedback) Convoys 1 and 2 -A-10

Part 11 Fast Speed - Vehicle Pairs - about 15 ruin. A-12

Part III -Intermittent Sound (Voice Feedback) Convoys 3 and 4 A-14

about 15 muin.

Part IV -Vehicle Pairs - Slow Speed - about 15 muin. A-15

Part V -Intermittent Sound - Practice Convoys 1,2,3, and 4 - A-16

about 10 ruin.

Part I -Continuous Sound (CPA Feedback) Convoys 1 and 2 - A-19

about 25 min.

Part 11 Vehicle Pairs - Fast Speed - about 15 min. A-22

Part III -Continuous Sound (CPA Feedback) Convoys 3 and 4 -A-23I

Part IV -Vehicle Pairs - Slow Speed - about 15 min. A-24

Part V - Continuous Sound - Practice Convoys 1,2,3, and 4- A-25

about 10 muin.

Posttest

Continuous - Convoys 1-10 - about 20 nin.

Intermittent - Convoys 1-10 - about 20 min.j

Continuous - Convoys 11-20 - about 22 muin.

Intermittent -Convoys 11-~20 -about 22 min.

29
FACILITATOR GUIDE

ORIENTATION BRIEFING (10 min.)

Facilitator: Read the following:

I want to welcome everyone here today. We are glad that you could make

it and can participate in the exercise we have planned. You will be

participating in this exercise a half-day today, a half-day tomorrow,

and half of the following day. We think you will find it interestine and 4

worthwhile to your job in the Remote Sensor Platoon. We will be spending

an hour briefing you and giving you an orientation as to what it is all

about. Before going any further, I want to introduce myself and my

associate and find, out who you are.

Introduction I

Recent requirements in the Army Unattended Ground Sensor (UGS) cominunity

have identified a need for human factors studies and training development

in the area of sound recognition while monitoring acoustic UGS. The need

for studies and training development in sound recognition is desired by

UGS field units, the REMBASS program, the United States Army Intelligence

Center and School at Ft. H1uachuca, and the NATO project "Avid Guardian" in

Europe.

Acoustic sensors are the best confirmation sensors in the Army today, but

their full potential has not been realized primarily because of a lack of

knowledge on the part of the commander and new system developers concerning

what the operator can and cannot do. Much of the information that the

commander can use doesn't even exist. That is why we are here--to collect

performance data which can be used by the commander and new system developers

for doctrine, tactics, and systems specification. By participatiig in this

exercise, you, the UGS operator, are helping to answer questions such as:

A-1 30
I. How well can an operator recognize different military

vehicles in convoy by listening to the sound that they make?

2. What difference does transmission time make, including very short ones? Using short transmission times has the advantages of

longer battery life and reduced chances of electronic detection.

3. To what extent can an operator be trained to increase his

ability to recognize the sounds of military vehicles in convoy?

4. Does increasing the frequency (freq.) ranqe significantly improve sound

recognition performance?4

The Army is interested in improving surveillance techniques to maximize

information output and make the job easier for you. Through its R~emotelyI Monitored Battlefield Surveillance System (REMBASS), the Army is currently

planning to include two acoustic sensors in its inventory for the 1980's.

These two REMBASS sensors are called the (1) Acoustic Analog Sensor

(DT-5XX) and the (2) Seismic/Acoustic Classification Sensor (DT-562).

The Acoustic Analog Sensor is simply an advanced version of the Audio

Add-On Unit (AAU) which you are familiar with. It will drive a speaker!

headset for aural analysis by the operator. Because the operator is

interpreting, the report is limited only by the operator's ability. Operator training plus differences in frequency may significantly improve his

performance.

The Seismic/Acoustic Classification Sensor will utilize internal logic

and digital information processing to automatically classify targets.

However, the classification is at a gross level and includes only tracked

vehicles, wheeled vehicles, and personnel. This sensor will send only a

beep every 10 seconds as its output. it will automatically display a T,

W, or P on the tac recorder.

During these ex~ercises, your task as a sensor operator will be to listen to

tape recordings of military convoys and report what you think you hear.

Many of the skills you have acquired in school and on the job will apply.

All of you probably have had personal experiences which will apply in that

you have heard all of the vehicles at soiimetime in your life. Today, you

will hear recorded sounds of Army vehicles which you will report on a

31 A-2
simple form called a Target Log. You'll do this for about an hour

and-a-half, and then receive some training. You will be given specific times

to ask questions so that the planned exercise will not be interrupted.

You will hear taped sounds of military vehicle convoys as you would hear

them from a modified MAU employed in a field exercise. The aggressor will

be traveling in convoys averaging about 10 vehicles (each traveling aboutI

6 seconds apart). The one problem you will have to deal with is the sound of

a loud vehicle partially degrading or masking the sound of a quieter vehicle.

Another problem is to make a quick decision about a particular vq'licle.

record it, and still listen to the convoy. You will record ycur answers

using our procedures 'and forms. Since we know what made the sounds, we

can score your report form~s for accuracy. We don't expect 100% performance

for all targets, but just that you try as hard as you can as though this

was a combat situation. As stated earlier, each of you will participate for

a half-day for three days. You must be here for all scheduled times or we

won't be able to use your results.

I would like to emphasize that we are not giving you a test to eee how

H good an operator you are. We are here to improve the Army's capability for

using the acoustic sensor. All we ask is that you interpret the sounds to the

best of your ability and try to make sense out of what sometimes might

V appear to you to be rather difficult. You are important because you as

a group represent the hundreds of UGS operators that have and will be

ksigned exerise. tof Thenuseof Paoonsusti shensorsti theftroilb partially i ti

asigned tof Rxemotse. Shenuseor Patoonsi but ori the firste tolb particiatlnlhiy

based upon what Lqu can do.

it is not the purpose of this exercise to sample all possible vehicles or

circumstances involving the use of acoustic sensor;. This exercise does

attempt to sample the sound signatures of certain types of vehicles in a

convoy situation using a certain type of sound recording system.

In addition to being relevant to your job in this platoon, there might be

another peýrsonal advantage for you to do well during this exercise. At

V various times trained volunteers are requested to serve in various places

UA-3 3
that you might find attractive, such as at Ft. Chaffee, Ark., or Europe.

Of course, there is no guarantee that even if you do well on this exercise you

will be swept away to a promised land, but doing well on this exercise sure

wouldn't hurt your chances. T

A-4 3
INSTRUCTOR GUIDEI

TEST PROCEDURE FAMILIARIZATION (40 min.)

Facilitator: Read the following

This exercise simulates the European theatre in which aggressor convoys

are attacking NATO's western boundary. Assume that you are in Germany

monitoring two types of acoustic sensors. These acoustic sensors are

similar to the AAU except that they "listen" at different tinias than

the AAU. As you know, the AAU "listens" for 15 seconds after being

triggered by three seismic activations within a 28-second period. YourI

first acoustic sensor will "listen" continuously for the type of

aggressor convoys expected. This first sensor we will call the

Continuous_ Sensor., Yu second sesrwill litnabout 4 eod for ec

vehicle. Since it listens intermittently, it is called the Intermittent

Sensor.

These sensors will present a target's sound signature to you when theI

Pi target is closest to the sensor. This point is called the CPA which stands

for closest-point-of approacn. This is the point where the vehicle should

[I sound the loudest and where you would have the best chance of identifying it.

Your commander has tasked you with the job of monitoring these acoustic

sensors for vehicle identification purposes. The order of battle (OB)

indicates that the aggressor force will be using convoys averaging around

10 vehicles apiece. Speed and traveling intervals of the convoys will

affect how you hear each vehicle but the vehicle separation will be

around 6 seconds. The first and last vehicles you will probably hear

longer.

Your commander has given you a Target Log which you will use to record 

'

vehicle activity. Look at the Target Log that is being passed out now.

(Pass out Target Logs). First, fill out the information that is requested

A-5

_4 .111
VEH JP GG 211T 5T IOT APC TNK -- VEIL ill GG 2-1i 5Lr 10T APC INK

Convoy 1 - Convoy 14

1 2 1 2.

3. 3..

34.---- 2...

5- 5...

8 -. - 8 - - - . - - - . - -

40 - .4

15 ... - 11

12--.-~~~ .-.- 12. Convoy I--. . . Convoy I- - - 4 2---4 2 ..

3-,.

4 -0. 4 - - . .

- .12.

Convoy 1.-. - - ..-. - Convoy 1..- - - . -

3 2.-- --- 3 2.-

3-3

4-___ 4.

6 -_ 5

7-6 7

9-.~r
along the right-hand side. Also, put your rank with your name. I'll wait

while you do this (about one minute). Notice at the top of the Target Log

that your commander is interested in seven vehicles that he knows will be

in these convoys. He wants you to place an X in the appropriate column

for each vehicle so that he can know how many of each kind in order to

determine the threat level. These target types are:

1. Jeeps (shown as JP)

2. Gamma Goats (shown as GG)

3. 2i-ton trucks (shown as 21⁄2T)

4. 5-ton trucks (shown as 5T)

5. 10-ton trucks (shown as lOT)

6. Armored personnel carriers (shown as APC)

7. Tanks (shown as TNK). Alnmst all the tanks are M-60's. If you

hear any Sheridan tanks, just list them as tanks along with the

M-60.

Notice that there are spaces for 10 convoys on your Target Log with a

maximum of 12 vehicles per convoy--five convoys are on the left and five

on the right. Are there any questions?

Before we go any further, we want to give you some practice int listening to

convoys and recording your answers on the Target Log. You will start on the

left-hand side of the Target Log. Notice again that there are five convoys

with a maximum of 12 vehicle answer spaces per convoy. A maximum of 12

vehicle answer spaces is given because your commander knows that the

aggressor convoys will have anywhere from five to 12 vehicles in each convoy.

In this study, five convoys will be equivalent to a Rn level unit.

During this exercise you will be told when a Bn of five convoys is

approaching. You will also be told when each convoy in the Bn is approaching

your acoustic sensor. This information is what you would normally get from

your seismic sensors. The convoys will be traveling at various speeds but

your intelligence reports indicate that the time separation between each

vehicle will be only 4-10 seconds.

Ai36 SA-7
Now, let's run through three convoys to make sure there aren't any

misunderstandings and to give you a little practice. The first convoy

is monitored by the CONTINUOUS SENSOR. Remember, for each vehicle in the

convoy, record your answer with an X. Try to maintain the proper

sequence of vehicles throughout the convoy and. start on the left side

of the Target Log where it says convoy 1. Are there any questions? OK.

If the sound is too loud, raise your hand.

Facilitator: Play mixed convoy out of training tape A (counter numbers

178-186). As this convoy is playing, check to see that

everybody understands the procedure.

OK, how did everybody do? Now I will give you the answers for this convoy

in the sequence that they occurred, then we will replay it.

(178) Vehicle 1 TNK

Vehicle 2 TNK

Vehicle 3 TNK

Vehicle 4 ITNK

Vehicle 5 APC

Vehicle 6 APC

Vehicle 7 APC

Vehicle 8 APC

Vehicle 9 APC

Vehicle 10 APC

Facilitator: Replay the convoy (185-203.5).

I think you will see t~hat you must concentrate on the sounds. Now we

will listen to another convoy. Remember to place an X in the right

column for your answers. It is important for you to start on the left

side of the Target Log where it says convoy 2.

Facilitator: Play wheeled ccnvoy (counter reading 186-190).

A-8 

37
OK, how did everybody do? Now I will give you the answers for this convoy

in the sequence that they occurred, then we will replay it.

(204) Vehicle 1 2kT

Vehicle 2 lOT

Vehicle 3 lOT

Vehicle 4 2__T

Vehicle 5 JP

Vehicle 6 JP

Vehicle 7 21⁄2T

Vehicle 8 JP

Vehicle 9 JP

Facilitator: Replay this convoy (204-211.5).

Now we will listen to another convoy in which the Intermittent Sensor is

used and each Vehicle will be heard about four seconds. It is important

that you start on the riqht side of the Target Log where it says convoy 1.

Any questions?

Facilitator: Play tracked convoy (027-035).

The answers to this convoy in the proper sequence are as follows:

(027.5) Vehicle 1 TNK

Vehicle 2 TNK

Vehicle 3 JP

Vehicle 4 APC

Vehicle 5 TNK

Vehicle 6 JP

Vehicle 7 GG

Facilitator: Replay this convoy (027-035). Answer any questions

before continuinwi.

Now you will be given four Bn's of convoys to monitor using both the

Intermittent Sensor and Continuous Sensor. Each Bn will have five convoys.

One Target Log is all you need to record your answers for both Bn's.

A-9 38
CONVOY SOUND RECOGNITION TRAINING

(50 - 2000 Hz Response)

(002) PART I-- INTERMITTENT SOUND - VOICE FEEDBACK

Facilitator: Before starting, give each soldier a fresh Target Log.

Step 1 -Instructions on Tape - You will now participate in a training program

(03) designed to increase your ability to recognize the individual vehicles

in convoys. Aggressor vehicles in convoy are expected to travel close

together (about 30 to 50 meters apart) at speeds of 20 - 40 kph depending

upon such considerations as visibility and road conditions. Also, they

are expected to average about 10 vehicles per convoy. Let us assume

that you are monitoring an acoustic sensor that is commanded to listen

to each vehicle for four seconds in such a convoy. Given the separation

distance and speed of this convoy, the vehicles would be about 4 to 8 or

10 seconds apart with an average separation time of 6 seconds. If your

acoustic sensor is on for four seconds, then there will be gaps of dead

time between the vehicles. These dead times will help you to know how

many vehicles are in each convoy.

Yuwill no ertwo Bnconvoys, hs convoys wilbe taeigaround

40 kph which is about 24 mph. Record your answers on your Target Log.

Take your Target Log now and fill in just your name and the date. I'll

wait while you do this.

(021) Facilitator: Stop tape and begin when everyone is ready.

Keep in mind what has just been discussed, and see how many vehicles you

can recognize. Remember to record your answers with an "X" on your Target

Log and start with Convoy 1 on the left-hand side.

Step 2 -Playback - Play convoys 1 (027-035) and 2 (1035-048)

(027) (4 sec condition).

A- 10 39
Step 3 - Feedback on Tape - OK, let's; see how you did. You should have

(049) gotten 6 vehicles for the first convoy and 8 vehicles for the second convoy.

Did anybody get this many? Let's see how you did with the sequence. Now

you will be given the answers to both convoys in the proper sequence. However, there is a special tas! for you to do on your Target Log. As I give

you each answer, draw a circle in the proper space with your pencil. Draw

the circle for each answer whetherYou__fot it right or not. Do this so

you can use this information later. Remember, draw a circle in the proper

space for each answer that I give you whether you got it right or not.

For those that you got rig it, the circle would surround the "X."

Convoy 1- Target is a TNK

Target 2 is a TNK

Target 3 is a JP

Target 4 is a APC

Target 5 is a TNK

Target 6 is a GG

j

Convoy 2'- Target 1 is a GG _

Target 2 is a GG

Target 3 is a GG

Target 4 is a JP _ _

Target 5 is a 214T

Target 6 is a 22T

Target 7 is a 2 T 1

,T

Target 8 is a 21T

Now add the total number of targets you got right and write the total at the

bottom of the page.

(073) Facilitator: Stop tape and begin when everyone is ready. We will now take

some time to make sure everybody understands the procedure and to answer any

questions you might have. Everybody take off his earphones and let's talk

for a minute.

(077.5) Facilitator: Stop tape and continue after the discussion. At this point allow the

A-11 40

• II
soldiers to respond to how well they performed and reinforce

rapport and interest. Make sure everybody recorded the

answers. Point out that if a vehicle was missed it would

upset the sequence of the remaining vehicles. If the

sequence were adjusted accordingly, the soldier might get

more correct. When this is finished, say, "OK, everybody

puthis earphones back on and let's continue."

Time this portion.

Step 4 - Instructions on Tape with Voice Feedback

(080) Now, we will play convoys 3 and 4. Again, you will record your answers on

the Target Log but in the convoy 3 and convoy 4 spaces. This time as you

hear the vehicles, you will be told the identity of each vehicle immediately

after you hear the sound. When you hear the sound of each vehicle, decide

what you think it is and q yiY record your answer on the Target Log. The

answer will then be given to you. This technique will tell you immiediately

if your answer is correct or incorrect. This technique will help you learn

where you're making your mistakes. Let's try it.

Step 5 - Replay with Voice Feedback

(089) Play convoy 3-and--4in 4-sec. condition with voice feedback.

(110) "Now take your earphones off and let's make sure everybody understands the

procedure."'

(112) Facilitator: Stop tape - start when discussion is over.

"OK, let's listen to these convoys again with voice feedback. This time,

don't use your pencil, ,just follow alonq in your mind and decide what each

vehicle is before you are told the answer."

Step 6 - Re-replay with Voice Feedback

(116)

(138) These convoys were played several times to help you to recognize these

vehicles when you hear them again in other convoys. Now let's go on.

(142.5) PART II - INTERMITTENT SOUND - PAIRED VEHICLES (40 kph - 24 mph)

Step I - Instructions on Tape. In this phase of the training you will be able to

compare the fast sound of one type of vehicle immediately with that of

another. This technique will help you to remember how each target sounds.

A-12 41
Try to draw from your experience what each vehicle sounds like to yiu.

To some of you, a particular vehicle might sound like a motorboat or a

Honda motorcycle, or a Greyhourl bus, or perhaps something else. In

other words, draw a picture in your mind as to what each vehicle sounds

like to you. Before each vehicle pair is presented, you will be told

which vehicle is presented first and which vehicle is presented second.

You will not use your Target Log for this exercise. You will now hear

22 vehicle pairs.

Step 2 - Playback. Play the vehicle pairs in the fast condition.

(156)

Comparison 1 is a JP and GG

Comparison 2 is a JP and 2!T

Comparison 3 is a JP and 5T

Comparison 4 is a JP and 10T

Comparison 5 is a JP and APC

Comparison 6 is a JP and TNK

Comparison 7 is a GG and 2Ij

Comparison 3 is a GG and 5T

Comparison 9 is a GG and lOT

Comparison 10 is a GG and APC

Comparison 11 is a GG and TNK

Comparison 12 is a 212T and 5T

Comparison 13 is a 212j and lOT

Comparison 14 is a 2'•T and APC

Comparison 15 is a 212T and TNK

Comparison 16 is a 5T and 10T

Comparison 17 is a 5T and APC

Comparison 18 is a 5T and TNK

Comparison 19 is a lOT and APC

Comparison 20 is a JOT -and TNK

Comparison 21 is a APC and TNK

Comparison 2'2 is a TNK (M60) and TNK (Sheridan)

A1

t A-I13 42
PART III -INTERMITTENT SOUND (with voice feedback) -Convoys 5 and 1

Step 1 -Instructions on Tape. Now you will hear two more convoys - convoy 5

(282.5) of the last IUn and convoy 1 of the next Bn. These convoys will be

moving more slowly at about 20 kph which is about the same as 12 mph.

Start recording your answers in the left-hand side convoy 5 position

and continue to the right-hand side convoy 1 position.

Step 2 -Playback. Play convoy 5(289.5) and new convoy 1 (308) in the 4 sec.

(289.5) condition.

Step 3 -Feedback. Okay, let's check how you did. You should have gotten 8

vehicles for the first convoy and 9 vehicles for the second convoy.

Let's see what you missed. Now you will be given the answers to both

convoys as before. Remember to draw circles in the proper spaces so

you can see where you missed. Convoy 5 is easy. All the vehicles are

APG's. I'll wait until you draw your circles.

Facilitator: Stop tape, begin when everybody is ready.

(335.5) Convoy 5 -Target 1 is a APC

Target 2 is a APC

Target 3 is a APC

Target 4 is a APC

Target 5 is a APC

Targjet 6 is a APC____

Target 7 is a __APC

Target 8 is a __APC

(338.5) Convoy 1I Target 1 is a TNK

Targe~t 2 *is a T.NK

Target 3 is a TNK

Target 4 is a TNK

Target 5 is a APC

Target 6 is a APC____

Target 7 is a APC ___-

Target 8 is a APC

jTarget 9 is a APC

A-14 43
Step 4 - Instructions on Tape with Voice Feedback

(345.5) Now we will play convoy 2 and convoy 3. Record your answers on the

Target Log in the convoy 2 and convoy 3 spaces. As before, you will

be told the identity of each vehicle immediately after you hear the

sound. Try to draw your X's before the answers are given. When you

miss a target, try to figure out why you missed it. Are you ready?

Let's go.

Step 5 - Replay with Voice Feedback

(354) Replay convoy 2 and convoy 3.

(393) Let's listen to these convoys again for more practice. Do not use

your pencil this time, just follow along and listen closely.

Step 6 - Replay with Voice Feedback

(436) These convoys were replayed to help you recognize these vehicles when you

hear them aga.in. Now let's go on. kV

,438.5 Part IV - INTERMITTENT SOUND-PAIRED VEHICLES (20 kph or 12 mph)

Step I Instructions on Tap. Now you will be given vehicle pairs as before except

the vehicle speeds will be slower. This technique will allow you to coinpare the sound of one type of vehicle with the sound of another type of

vehicle. Try to draw a picture in your mind as to what each vehicle sounds

like to you. Before each vehicle pair is present you will be told which

vehicles are being coinpared. Do not use your Target Log, just listen

closely.

Step 2 -Playback -Play the vehicle pairs in the slow condition.

(448.5)

A-15 44
Comparison I is a JP and GG

Comparison 2 is a JP and 2!jT

Comparison 3 is a JP and 5T

Comparison 4 is a JP and lOT

Comparison 5 is a JP and APC

Comparison 6 is a JP and TNK

Comparison 7 is a GG and 21T

Comparison 8 is a GG and 5T

Comparison 9 is a __GG and OT

Comparison 10 is a GG and APC

Comparison 11 is a GG and TNK _

Comparison 12 is a GG and 5TN

Comparison 13 is a 2;jT and 1OT

Comparison 14 is a 2j'T and APC

Comparison 15 is a 2!jT and TNK :_

Comparison 16 is a 5T and lOT

Comparison 17 is a 5T and APC _

Comparison 18 is a 5T and TNK

Comparison 19 is a lOT and APC

Comparison 20 is a lOT and TNK

Comparison 21 is a APC and TNK

Comparison 22 is a TNK M60) and TNKLSheridan)

(592) PART V - INTERMITTENT SOUND - PRACTICE CONVOYS 1, 2, 3, and 4.

Step I Instructions onTap•e - Let's see what you have learned. We will

(594) play four convoys and then you can score yourself. Fill out your name

and the date on a new Tarijet Log.

(597) Facilitator: Stop tape until everybody is ready. "Start with convoy I

on the left-hand side of the Target Log. Listen closely to these four

convoys and see how many vehicles you can get."

Step 2 - Play convoys 1 (602.5), 2 (619), 3 (643), and 4 (664).

(602.5)

A-16
Step 3 - Feedback and Self-Scoring on ta p- O.K., let's see how yOU

(677) did. Draw your circles as I give you the answers. Ready?

(679) Convoy 1 - Target 1 is a GG

Target 2 is a GG

Target 3 is a GG

Target 4 is a JP

Target 5 is a 2VT

Target 6 is a 21⁄2T

Target 7 is a 21⁄2T

Target 8 is a 2VT

(688) Convoy 2 - Target I is a TNK

Target 2 is a TNK

Target 3 is a TNK

Target 4 is a TNK

Target 5 is a APC

Target 6 is a APC

Target 7 is a APC

Target 8 is a APC

Target 9 is a APC

(697) Convoy 3 Target 9 is a APC

Target 2 is a APC

Target 3 is a APC

Target 4 is a APC

Target 5 is a APC

Target 6 is a APC

Target 7 is a APC

Target 8 is a APC

(699.5) Facilitator: Stop tape and begin when everyone is ready.

(701.5) Convoy 4 - Target 1 is a TNK

Target 2 is a TNK

Target 3 is a _JP

Target 4 is a APC

Target 5 is a TNK

"j jet 6 is a GG

A- 17 46
(707) How many vehicles did you get? Add them up now and put the total by

your name.

(709) Facilitator: Stop tape until everybody is finished.

(710.5) Now, if you leftsome vehicles out at the beginning of a convoy, that

would really mess you up, right? It would make it look like you missed

a Ioc more vehicles than you actually did. So, I want you to score

yourself a different way. Add up the total number of vehicles that

you got in each target category. Add up the total number of jeeps,

gamma goats, 21⁄2-T, etc. Record the totals at the bottom of your

Target Log.

(721) Facilitator: Stop tape until everybody is ready.

(723.5) Ground truth says there are 2 JP, 4 GG, 4 21⁄2T,

0 ST, 0 lOT, 14 APC, and 7 TNK. If you

got a perfect score you are quite exceptional. All right, this

finishes this phase of the training. Leave your Target Logs on your

desk and we'll take a 15-minute break.

(734) Facilitator: Stop tape, take the break and resume with the continuous

convoy sound recognition section of the training.

A-18

.. ........... ..
(737) CONVOY SOUND RECOGNITION TRAINING

(50 -2000 Hz Response)

(739) PART I -CONTINUOUS SOUND (With CPA feedback) -Convoys 1 and 2

Facilitator: Before starting give each soldier a fresh Target Log.

Step 1 - nstructions on Tape_ - You will now participate in a training

(741) program designed to increase your ability to recognize the individual

vehicles in convoys. Aggressor vehicles in convoy are expected to

travel close together or about 30 meters to 50 meters apart at speeds

of 20 - 40 kph, depending upon visibility and road conditions. Let

us assume that you are monitoring an acoustic sensor that is conmmanded

to collect continuous sound for such convoys. What this means is that

you will only have about 6 seconds on the average to identify any one

vehicle within such a convoy. Because convoys tend to bunch-up and

spread-out, you may have only 4 seconds or up to 8 seconds or more to

listen to the sound of any one vehicle. However, you may have more

time to identify the first and last vehicle. For example, you may

hear the first vehicle in the distance as the sound gets louder and

louder so naturally you would have more time to identify the first

vehicle. In a similar way, you may have more time to identify the

last vehicle as the sound trails off. However, the fact remains that

you will not have much time to identify the vehicles within the

convoy. Again, you will only have about 6 seconds or less depending

upon how much the sound of one vehicle is interfering or masking the

sound of another vehicle.

Another poo~t to keep in mind is to use the above information in

reverse. That is, since you know that the aggressor vehicles are only

about 6 seconds apart, you can conclude that you should-be recognizing

a different vehicle about every 6 seconds.

* A- 19 48
You will now hear two convoys - one composed of wheeled vehicles and

the other composed of both wheeled and tracked vehicles. These convoys

are traveling around 40 kph which is about 24mph. Keep in nmind

what has just been discussed and see how many vehicles you can detect

and recognize. Take your Target Log now and fill out your name. I'll

wait until you do this.

(792) Facilitator: Stop tape - start when everybody is ready.

Okay, is everybody ready? Remember to record your answers with an "X" on

your Target Log and start with Convoy 1 on the left-hand side.

Step 2 - Playback - Play Convoys 1 (800) and 2 (821). Continuous

sound condition.

Step 3 - Feedback on Tape - Okiy, how did you do? Did everyone get 9 vehicles

(844) for the first convoy and 8 vehicles for the second convoy? Now you

will be given the answers to both convoys in the proper sequence.

However, there is a special task for you to do on your Target Log.

As you are given each answer, draw a circle in the proper space with

your pencil. Draw the circle for each answer whether you got it

right or not! Do this so you can use thisinformation later. OK?

Remember now, draw a circle in the proper space for each answer that

I give you whether you got it right or not. If you got one right, then

the circle would surround the "X."

(858,5) Convoy 1 - Target 1 is a 5T

Target 2 is a TNK

Target 3 is a TNK

Target 4 is a __ l01T

Target 5 is a JP

Target 6 is a TNK

Target 7 is a __ JP

Target 8 is a Sheridan TNK

Target 9 is a APC

A-20 49
(872) Convoy 2 - Target I is a GG

Target 2 is a GG

Target 3 is a JP

Target 4 is a GG

Target 5 is a 2!,T

Target 6 is a 2VT

Target 7 is a 2VT

Target 8 is a 2VT

OK, everybody take off his earphones and let's see how well we did. Also

this will be a time to make sure everybody understood the procedure

and also to answer any questions.

(890) Facilitator: "Stop tape and have a group check"- At this point allow

the soldiers to respond to how they performed and

reinforce rapport and interest. Make sure everybody recorded the ground truth answers. Point out the

distinctive tone of the Sheridan tank. Answer

questions and be responsive to needs of group. When

this is finished, say, "OK, everybody put his earphones

back on and let's continue."

Step 4 -Instructions for Repja on Tape - Now we will r( lay both

(894) convoys so you can listen to the sounds and compare your answers with

the ground truth answers that you just recorded. As these convoys are

replayed, you will notice that a short tone will signal when each

vehicle is closest to the sensor. This point is called the closest.

point-of-approach or CPA for short. Now we will replay Convoys I

and 2 with a tone at each vehicle CPA. Remember to follow your

Target Log closely. You don't have to make a report - just try to

learn to recognize each individual vehicle in your mind.

Step 5 - _Replaywith CPA on Tape_ - Replay Convoys 1 (908) and 2 (928.S) with CPS.

(908) with CPA. (951) "Let's listen one more time to this samne

convoy with the CPA tones. First, however, remove your earphones and

let's make sure everybody understands the CPA tone."

(955) Facilitator: Stop Tape for Group Check. Explain again the significance

of the CPA tone and how it differs from tape recorder clicks between targets

in the continuous mode.

A-21 50
Step 6 - Re-replay with CPA - Re-replay Convoys 1 and 2 with CPA.

(957)

(999) PART I - CONTINUOUS SOUND - PAIRED VEHICLES (40 kph - 24 mph)

Step 1 - Instructions on Tape - In this phase of the training you will be able

(1001) to compare the sound signature of one vehicle imnediately with that

of another. This technique will help you to remember how each

target sounds. Try to draw from your experience what each vehicle

sounds like to you. To some of you, a particular vehicle might

sound like a motorboat, or a Honda nxmtorcycle, or a Greyhound bus, or

perhaps something else. In other words, draw a picture in your

mind as to what each vehicle sounds like to you. Before each vehicle

pair is presented, you will be told which vehicle is presented first

and which vehicle is presented second. You will not use your Target

Log for this exercise. You will now hear 22 vehicle pairs.

Step 2 - Playback - Play the vehicle pairs in the fast condition.

(1022.5)

Comparison 1 is a JP and GG

Comparison 2 is a JP and 2jT

Comparison 3 is a JP and 5T

Comparison 4 is a JP and S0T

Comparison 5 is a JP and APC

Compari.son 6 is a - .JP and TNK

Comparison 7 is a __GG and 2AP

Comparison 8 is a GG and 5T

Comparison 9 is a GG and 10T

Comparison 10 is a GG and APC

Comparison 11 is a GG and TNK

Comparison 12 is a 2!G and 5T

Comparison 13 is a 21jýT and 10T

Comparison 14 is a _____?LT and APC

Comparison 15 is a 21T and TNK

Comparison 16 is a 5T and lOT

Comparison 17 is a 5T and APC

Comparison 18 is a 5T and TNK

A-22 51
Comparison 19 is a .OT and APC

Comparison 20 is a lOT and TNK

Comparison 21 is a APC and TNK

(1247.5) Comparison 22 is a TNK (M60) and TNK (Sheridan)

PART III - CONTINUOUS SOUND (with CPA feedback) - Convoys 3 and 4

Step 1 - Instructions on Tape - Now you will hear convoys three and four. The

(1264) third convoy is traveling slowly at about 20 kph or 12 mph. The

fourth convoy is traveling at about 40 kph or 24 mph. Start

recording your answers on the Target Log in the convoy 3 position

then go to the convoy 4 position. Let's go!

Step 2 - Playback - Play tracked convoy and wheeled convoy continuous

(1279.5) sound condition.

Step 3 -Feedback on Tape - You should have gotten 10 vehicles for

(1343) convoy 3 and 8 vehicles for convoy 4. If you got them all right, you're

exceptional. Now you will be given the answers to both convoys as

before. Remember to draw circles in the proper spaces so you will

have your copy of the answers for later use.

(1356) Convoy 3 - Target 1 is a TNK

Target 2 is a TNK

Target 3 is a TNK

Target 4 is a TNK

Target 5 is a APC

Target 6 is a APC

Target 7 is a APC

Target 8 is a APC

Target 9 ir a APC

Target 10 is a APC

A-23 52
(1374) Convoy 4 - Target 1 is a 21T

Target 2 is a lOT

Target 3 is a lOT

Target 4 is a 21J

Target 5 is a JP

Target 6 is a JP

Target 7 is a 212T

Target 8 is a JP

(1390) Facilitator: "Let tape run out and continue on the other side of the tape"

(Side 2)

Step 4 - Instructions on Tape for Replay. Now we will replay both convoys so you can

(001) listen to the vehicle sounds and compare your answers with the ground truth

answers you have just recorJed. As before, a tone will signal the CPA for

each vehicle. Do not record information on your Target Log, just follow

it closely, especially the vehicles that you missed.

Step 5- Re•lay on Tapewith CPA - Replay convoys 3 (006) and 4 (024).

(031) To give you more practice we will replay these same two convoys with

the CPA tone.

Step 6 - Re-replay with CPA - Re~replay convoys 3 and 4.

(059) Playing these convoys over several times should help you to

recognize these vehicles when you hear them again. OK. Let's go on.

(062) PART IV - CONTINUOUS SOUND - PAIRED VEHICLES (20 kph or 12 mph)

Step I - Instructions - Now you will be given vehicle pairs as before except

(063.5) the vehicle speeds will be slower. This technique will allow you to

compare the slow sound of one type of vehicle with the slow sound

of another type of vehicle. Try to draw a picture in your mind as to

what each vehicle sounds like to you. Before each vehicle pair is

presented, you will be told which vehicles are being compared. Do

not use your Target Log, just listen closely.

Step 2 - Playback Play the vehicle pairs in the slow condition.

(069)

A-24 53

"---- --
Comparison 1 is a JP and GG

Comparison 2 is a JP and 2VT

Comparison 3 is a JP and 5T

Comparison 4 is a JP and lOT

Comparison 5 is j JP and APC

Comparison 6 is a - JP and TNK

Comparison 7 is a JP and 2VT

Comparison 8 is a GG and 5T

Comparison 9 is a GG and lOT

Comparison 10 is a GG and APC

Comparison 11 is a GG and TNK

Comparison 12 is a 2-jT and 5T

Comparison 13 is a 214T and lOT

Comparison 14 is a 21⁄2T and APC

Comparison 15 is a 21⁄2T and TNK

Comparison 16 is a 5T and lOT

Comparison 17 is a 5T and APC

Comparison 18 is a 5T and TNK

Comparison 19 is a lOT and APC

Comparison 20 is a lOT and TNK

Comparison 21 is a APC and TNK

Comparison 22 is a TNK (M60) and TNK (Sherilan)

PART V - CONTINUOUS SOUND - PRACTICE CONVOYS 1, 2, 3, and 4.

Step 1 - Instructions - Now let's see what you have learned. We will play four

(181.5) convoys and then you can score yourself. Start with convoy 1 on the

right-hand side of the Target Log. Listen closely and see how well you

can do.

Step 2 -Play convoys 1 (185), 2 (204), 3 (212), and 4 (224).

(185)

Step 3 OK, let's see how you did. You will now be given the answers. Draw

(237) ur circles as I give you the answers.

A-25 54

______ __
(239.5) Convoy 1 

- Target 1 is a TNK

Target 2 is a TNK

Target 3 is a TNK

Target 4 is a TNK

Target 5 is a APC

Target 6 is a APC

Target 7 is a APC

Target 8 is a APC

Target 9 is a APC

Target 10 is a APC

(247) Convoy 2 

- Target 1 is a 21⁄2T

Target 2 is a lOT

Target 3 is a 101

Target 4 is a 2-jT

Target 5 is a JP

Target 6 is a JP

Target 7 is a 2VT

Target 8 is a JP

Target 9 is a JP

(254.5) Convoy 3 

- Target 1 is a GG

Target 2 is a GG

Target 3 is a JP

Target 4 is a GG

Target 5 is a 21⁄2T

Target 6 is a 2'

2

T

Target 7 is a 2Yj

Target 8 is a 2'1T

A-26 55
(261) Convoy 4 - Target 1 is a 5T ._

Target 2 is a TNK

Target 3 is a TNK

Target 4 is a lOT

Target 5 is a JP

Target 6 is a TNK

Target 7 is a JP

Target 8 is a Sheridan TNK

Target 9 i•s a APC

(269.5) How many vehicles did you get right? Add them up

by your name. I'll wait while you do this.

(272) Facilitator: Stop tape, start when everyone is ready.

(277.5) Okay let's try a different way of scoring. If you left out some vehicles at

the beginning of a Lonvoy, that would really mess you up, right? It might

make it look like you missed a lot more than you actually did. So, now I want

you to score yourself a different way. Add up the total number of vehicles

that you got in each category. In other words, add up the total number of jeeps,

gamma goats, 2!ton trucks, etc., and record the totals for each

vehicle category at the bottom of your Target Log. I'll wait while

you do this.

(287) Facilitator: Stop tape, start when everyone is ready.

(296.5) Ok, is everybody ready? Ground truth says there are 7 JP, 3 GG, 7 21⁄2T,

1 5T, 3 lOT, 7 APC, and 8 TNK. If anybody got a perfect score, who

are you trying to kid? This completes this portion of the training program.

(3CO) Facilitator: Stop tape and finisn up.

A-27 56
APPENDIX B

PRACTICE EFFECTS

Period effects were significant and appear to indicate a practice

effect. However, other considerations argue against it. An analysis of

whether practice is involved must consider the possible effects of using

scenario A for two successive periods and scenario B for two successive

periods (see Table 7). Scenarios were presented either in the continuous

or intermittent transmission mode. Familiarity from the first presentation to the next could have been enough to increase period 2 performance.

It is possible that if new convoy sounds had been used, the period effect

would not have been significant. One way of testing whether a practice

effect was operating is to conduct an odd/even analysis within each period.

As shown in Table B-1, each period is composed of two batLilions of five

convoys each. If the odd battalions result in a greater or equal performance compared to the even battalions, then it is unlikely that a practice

effect has occurred assuming that the battalions are equal in difficulty.

Table B-1 shows an odd/even analysis performed onl the pre/post data of

the 7-target case.

As indicated by the overall total identifications for the pretest,

posttest, and combi!ned results, identification in the even battalions

total less than in odd battalionsz, suggesting that a practice effect did

not occur. However, it should In noted that thle individual battalion results indicate that there is a consistent increase in performance for thle

second presentation of the same battalion. Even though the odd/even overall totals suggest that no practice effect occurred, the fact that the

second reolication of eacti battalion led consistently to higher scores

suggests that a practice effect specific to the vehicles in a convoy did

occur. Trhat is, there is no evidence that this transferred to different

convoys. Also, this effect should have been transitory in nature and

have largely disappeared when the next scenario was given. Learning

specific to repeated administrations of scenario A should have dissipated

upon administration of scenario B. Thus, little or none of this practice

effect would be carried over to the posttest presentation of scenario A.

Similarly, thle special training qiven also would tend to dissipate practice effects specific to the particular vehicles of a scenario. Although

a practice effect may have occurred, its effects are minimal compared to

thle pre/posttest comparison of the effects of training.

Further evidence concerning the lack of practice effects was obtained

in an experiment concerning signal/noise ratio (to be reported separately).

Four levels of signal/noise ratio, four groups of operators, four periods

(practice effects), and four scenarios were investigated using a grecolatin square design. The same convoys as in the present study were used

with the addition of several new convoys obtained from the same basic

maneuver convoy data. The mean identification percentages for each successive period are presented in Table B-2. The analysis of variance results indicated significance differences at the .01 level for period effects. However, this difference was due to the low value of period 2 and

not to practice effects.

57
Table B-i

Odd/Even Analysis of Practice Effect for 7-Target Category

Scenario A Scenario B

First period Second period First period Second period Overall

BN1 BN2 BN1 BN2 BN3 BN4 BN3 BN4 totals

Pretest

Odd 181 219 227 271 898 Even 216 239 160 178 793

Posttest

Odd 297 308 339 351 1295

Even 334 348 240 242 1174

Combined

Odd 478 527 566 622 2193

Even 560 587 400 420 1967 I

Table B-2

Mean Percent Correct Identification for the 7-Target Category

(Signal/Noise Experiment by Periods)

Period 1 Period 2 Period 3 Period 4

% Correct 28% 22% 27% 26%

58

- t & l-&&.<Žl .X4 
- -.... r. .....

DISTRIBUTION

ARI Distribution List

4 OASD (M&RA) 2 HOUSACDEC, Ft Ord, ATTN: Library

2 HODA (DAMI.CSZ) 1 HOUSACDEC, Ft Ord, ATTN: ATEC-EX-E-Hum Factors

I HODA (DAPE.PBR 2 UI %EEC, Ft Benjamin Harrison, ATTN: Library

I HODA IOAMA-AR) I L APACDC, Ft Benjamin Harrison, ATTN: ATCP-HR

1 HODA (DAPE.HRE.PO) 1 USA Comm-Elect Sch, Ft Monmouth, ATTN: ATSN-EA

1 HODA (SGRD.IDI 1 USAEC, Ft Monmouth, ATTN: AMSEL-CT-HDP

1 HODA (DAMI.DOTC) 1 USAEC, Ft Monmouth, ATTN: AMSEL-PA-P

I HODA (DAPC.PMZ.AI 1 USAEC, Ft Monmouth, ATTN: AMSEL-SI-CB

I HODA (DACH-PPZ-AI I USAEC, Ft Monmouth, ATTN: C, Facl Day Br

1 HODA (DAPE.HRE) 1 USA Materials Sys Anal Agcy, Aberdeen, ATTN: AMXSY-P

1 HODA (DAPE.MPOC) I Edgewood Arsenal, Aberdeen, ATTN: SAREA-BL-H

1 HODA (DAPE-DW) I USA Ord Ctr & Sch, Abordeen, ATTN: ATSLL-TEM-C

1 HQDA (DAPE-HRL) 2 USA Hum Engr Lab, Aberdeen, ATTN: Library/Dir

SHODA (DAPE.CPS) 1 USA Combat Arms Tng Bd, Ft Banning, ATTN: Ad Supervisor

1 HODA (DAFD.MFA) I USA Infantry Hum Rsch Unit, Ft Banning, ATTN: Chief

HODA (DARD-ARS-P) I USA Infantry Bd, Ft Banning, ATTN: STEBC-TE-T

1 HQDA (DAPCPAS.AI 1 USASMA, Ft Bliss, ATTN: ATSS-LRC

1 HfDA (DUSA.ORi 1 USA Air DOf 5ch, Ft Bliss, ATTN: ATSA-CTD-ME

1 HUDA (DAMO.RQR) 1 USA Air Def Sch, Ft Buiss, ATTN: Tech Lib

IHOA WASG) 1 USA Air Def Bd, Ft Bliss, ATTN: FILES

HGDA (DAI0-PII I USA Air Daf Sd, Ft Bliss, ATTN: STEBD-PO

Chief, Consult Div (DAOTSGi, Adelphi, MD 1 USA Cmd & Gsneral Stf College, Ft Leavenworth, ATTN: Lib

Mil Anst. Hum Ras, ODDR&E, OAD IE&LS) 1 USA Cmd & General Stf College, Ft Leavenworth, ATTN: ATSW-SE-L

1 HG USARAL, APO Seattle, ATTN: ARAGP.R 1 USA Cmd & General Stf College, Ft Leavenworth, ATTN: Ed Advisor

I HQ First Army, ATTN: AFKA.OI.TI 1 USA Combined Arms Cmbt Dev Act, Ft Leavenworth, AFTN: DepCdr

2 HO Fifth Army, Ft Sam Houston 1 USA Combined Arms Cmbt Dev Act, Ft Leavenworth, ATTN: CCS

I Dir, Army StO Studies Ofc, ATTN: OAVCSA (DSP) 1 USA Combined Arms Cmbt Dey Act, Ft Leavenworth, ATTN: ATCASA

Oft Chief of Stf, Studies Ofe 1 USA Combined Arms Cmbt Dey Act, Ft Leavenworth, ATIN: ATCACO-E

DCSPEHI, ATTN: CPS/OCP 1 USA Combined Arms Cmbt Dev Act, Ft I eavenworth, ATTN: ATCACC-CI IThe Army Lib, Pentagon, ATTIN: RSB Chief IUSAECOM, Night Vision Lob, Ft Bvivoir, ATT'N: AMSEL-NV-SD•

I The Army Lib, Pentagon, ATTN: ANRAL 3 USA Computer Sys Cmd, Ft Ealvoir, ATTN: Tech Library

I Ofc, Asut Sect of the Army WR0DI I USAMERDC, Ft Belvoir, ATTN: STSFB-DO

1 Tech Support Ofc, OJCS 1 USA Eng Sch, Ft Belvoir, ATTN: Library

1 USASA, Arlington, ATTN: IARD-T I USA Topographic Lab, Ft Belvoir, ATTN: ETL -TD-S

1 USA Rsch Oft, Durham, ATTN: Life Sciences Dir 1 USA Topographic Lab, Ft Belvoir, ATTN: STINFO Center

2 USARIEM, Natick, ATTN: SGRD.UE.CA I USA Topographic Lab, Ft Belvoir, ATTN: ETL-GSL USATTC, Ft Clavton, ATTN: STETC.MOA 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: CTD-MS

I USAIMA, Ft Bragg, ATTN: ATSU.CTD-OM 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: ATS-CTD-MS

1 USAIMA, Ft Biagg, ATTN: Marquat Lib 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: ATSI-TE

1 US WAC Ctr & Sch, Ft McClellan, ATTN: Lit) USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: ATSI-TEX-GS

1 US WAC Ctr & 9-h, Ft McClellan, ATTN: Tng Dir 1 USA Intelligence Ctr & Sch, Ft Huechuca, ATTN: ATSI-CTS-OR

I USA Quartermaster Sch, Ft Lee, ATTN: ATSM-TE 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: ATSI-CTD-DT

Intelligence Material Dev Of,., EWL. Ft Holabird 1 USA Intelligence Ctr & Sch, Ft Huechuca, ATTN: ATSI-CTD-CS

I USA SE Signal Sch, Ft Gordon, ATTN: ATSO.EA 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: DAS/SRD

I USA Chaplain Ctr & Sth, Ft Hamilton, ATTN: ATSC-TERD 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: ATSI-TEM

1 USATSCH, Ft Eustis, ATTN: Educ Advisor 1 USA Intelligence Ctr & Sch, Ft Huachuca, ATTN: Library

1 USA War College, Carlisle Barracks, ATTN: Lib 1 CDR, HO Ft Huachuce, ATTN: Tech Ref Div

2 WRAIR, Neuropsychiatry Div 2 CDR, USA Electronic Prvg Grd, ATTN: STEEP-MT-.S

1 DLI, SDA, Monterey 1 CDR, Project MASSTER, ATTN: Tech Info Center

I USA Concept Anal Agcy, Bethesda, ATTN: MOC/'-WGC 1 Hq MASSTER, USATRADOC, LNO

I USA Concept Anal Agcy, Bethesda, ATTN: MOCA*MR 1 Reserch Institute, HO MASSTER, Ft Hood

1 USA Concept Anal Agcy, Bethesda, ATTN: MOCA-JF USA Recruiting Cmd, Ft Sherdian, ATTN: USARCPM-.P

I USA Artic Test Ctr, APO Seattle, ATTN: STEAC-MO-ASL 1 Senior Army Adv, USAFAGOD/TAC, Elgin AF Aux FId No. 9

USA Artic Test Ctr, APO Seattle, ATTN: AMSTE.PL.TS 1 HO USARPAC, DCSPER, APO SF 96558, ATTN: GPPE-SE

USA Armament Cmd, Redstone Arsenal, ATTN: ATSK.TEM 1 Stlmson Lib, Academy of Health Sciences, Ft Sam Houston

I USA Armament Cmd, Rock Island, ATTN: AMSAR.TDC 1 Marine Corps Inst,0 ATTN: Dean--MCI

FAA-NAFEC. Atlantic City, ATTN: Library 1 HOUSMC, Commandant, ATTN: Code MTMT 51

I FAA-NAFEC, Atlantic City, ATTN: Hum Engr Sr 1 HQUSMC, Commandant, ATTN: Code MPI-20

I FAA Aeronautical Ctr, Oklahoma City, ATTN: AAC-44D 2 USCG Academy, New London, ATTN: Admission

2 USA FId Arty Sch, Ft Sill, ATTN: Library 2 USCG Academy, New London, ATTN: Library

1 USA Armor Sch. Ft Knox, ATTN: Library 1 USCG Training Ctr, NY, ATTN: CO

I USA Armor Sch, Ft Knox, ATTN: ATSB.DI-E 1 USCG Training Ctr, NY, ATTN: Educ Svc Ofc

1 USA Armor Sch, Ft Knox, AnrN: ATSB.DT-TP 1 USCG, Psychol Ras Br, DC, ATTN: GP 1/62

1 USA Armor Sch, Ft Knox, ATTN: ATSB-CD-AD 1 HO Mid-Range BR , MC Det, Ouantico, ATTN: P&S Div

59

.....I.
I US Marine Corps Lialsion Ofe, AMC, Alexandria, ATTN- AMCGS-F 1 Oaf & CMI Innt of Enwlro Medicin, Cansedo

I USATRADOC, Ft Monrwo, ATTN: ATRtO-lOD IAINR cR1,KesakWlsn ATTN: Info slWeI

6 USATRADOC, Ft Monroe, ATTN: ATPA-AO D~lWIIII Tjorwil, r('4piIUf

11 USATRADOC, Ft Monroe, ATTN: ATTS.-EA IMliftz Atleha, Preach Em bemy, ATTN: Doe See

I UISA Forces Cmd, Ft McPherson, ATrN: Library i Msdooin Choll, O.EPA.-Asoienil, Toulon/Noesl Franm

2 USA Aviation Test 6d, Ft Ruckrer. ATT'N: STESO11-10O I PrISS SuonfsOt elHmla etDv ier

1 USA Allay for Aviation Safety, Ft Ruckar, ATTN: Library of eense - Ne ~w Delhi

1 USA Agcy for Aviation Safety, Ft Rucker, ATTN: Educ Advisor I heas Ruh Oft Llbray, AKA. larvel Defores Formi

I USA Aviation Sch, Ft Rucker, ATTN: PO Drawe 0 1 Mlnlasaris von Defoaels, O0P0/KL Afd Soocical

I HOUSA Aviation Sys Cmd, St Louis, ATTN: AMSAV-ZDR lops*Y1O~h Zake. The Naow, Netherlads

2 USA Avkt~f v *art im Act., Edwa"d AFB, ATTN! SAVTE-T

I USA Air Def Sch, Ft Bliss, ATTN: ATSA TEM

I USA Air Mobility Rich~ i Day Lab, Moffatt FId, ATTN: SAVOL-AS

1 USA Aviation Sch, Ras Tng Mot. Ft Rucker, ATTN-: ATST-T-RTM

1 USA Aviation Sch, CO, Ft Rucker, ATTN: ATST-D-A

1 HO, DARCOM. Alexandria, ATTN: AMXCD-TL

1 HO, DARCOM, Alexandria, ATTN: CDR

1 US Military Academy. West Point, ATTN: Serials Unit

1 US Military Academy, West Point, ATTN; Ofc of Milt Ldrshp

I US Military Academy, Wast Point, ATTN: MAOR

1 USA Standardization (3p, UK(, FPO NY, ATT'N: MASE-GC

1 ONe of Naval Ruh~, Arlington, ATTN: Coda 452

3 Ofc of Naval Fisch, Arlington, ATTN: Code 458

IOfe of Naval Rich, Arlington, ATTN: Code 450

IOlc of Naval Rsch, Arlington, ATTN: Code 441

1 Navai Aarospe Mad Ras Lab, Pensacola, ATTN: Acous Sch Div

Naval Aerospc Med Res Lab, Pensacola, ATTN: Code L51

I Naval Aerospe Med Res Lab, Pensacola, ATTN: Code L5

ý'j I Chief of NayPars, ATTlj: Pert-OR

I NAVAI RSTA, Norfolk, ATTN: Safety Ctr

I Nay Oceanographic, DC, ATTN: Code 8251, Charts &Tech

I Center of Naval Anal, ATTN: Doc Ctr

I NavAirSysCorn, ATT'N: AIII-6313C

1 Nov IluMed, ATI`N: 7131

1Nov Heiicpte rSubSqus 2, FPO SF 98601

11AFHRL l(-TI William AFB

1APHRL ITT) Lowry AFB

1 APHRL (AS) WPAF8, OH

2 AFHRL iDOJZ) Brooks AFB

I APHRL (DOJNI Lacklanri AFS

1 HOUSAI (INYSDI

1 HOUSAF (DPXXA)

IAI-VTG (RD) Randolph AFB

3 AMRL (HOIWPAra. OH

21 AF Iost of Tcch, WPAFB, OH, A'rTN: ENE/SL

I ATC IXPTUi HRrndoiph APO

1 USAF Aerolled Lib, Bfrooks AFS ISUL-4), ATTN: DOC SEC

1 AFOSR (NLI, Arlington

1 AF Log Cmd, Mc~lellan AFB, ATTNt ALC/OPCR8

I Air Forcs Academy, CO. ATTN: Dept of eal Sen

5 NavPors & Van Ctr, San Diego

2 Navy Med Neuropsycisiatrlc Rich Unit, San Diego

I Nay Electronic Lab, Son Dieglo, ATTNý Res Lab

1 Nay TrnqCen, Son Diego, ATTN: Code 9(IQO-Llb

1 NavPostGraSch, Morteomy, ATTN: Code 66A&

'VI rNsvilostGraSch, Monterey, ATTN: Coda 2124

I NavTrngEquipCtr, Orlando, ATTN: Tech Lib

1 US Dvpt of Labor, DC, ATTN: Manpower Adriin

I US Dept of Justice, QC, ATTN: Drug Enfocce Admin

1 Nat Our of Standards. DC, ATTN: Computer Info Section II Nat Clearing House for MH.-Info, Rockville

1 Denver Federal Ctr, Lakewood, ATTN: BLM

12 Defense Documentation CanterI

4 DIr Psych, Army Hq, R~ussell Ofes, Canberra

1 Scientif ic Advir, Mil 8d, Army Hq, Russell Ofet, Coanbera

1 Mul ard Air Attache, Austrian Embeassy

I Centra do Racerche Des Faetours, Humaine dalIs Detente

Nationale, f8russnnis

2 Conadlin Joint Staff Wathington

1 C/Air Staff, Royal Canadian AF. ATTNi Port Std Anal Sr

3 Chief, Canadian Def Rreh Staff, ATTN: C/CRDS(WI

4 British Def Staff. 5r'.Ish Embasay, Waahington

60

........I