bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of Acoustic Fields about Arbitrary Three-Dimensional Bodies
Authors: Hess John L.
Published: November 2005

A general method is described for calculating radiated and scattered sound fields about three-dimensional bodies. The method utilizes a source distribution on the surface of the body and solves for the distribution necessary to satisfy the boundary conditions. Plane quadrilateral surface elements are used to approximate the body surface, and the integral equation for the source density is replaced by a set of linear algebraic equations for the values of source density on the quadrilateral elements. Once the source density is known, acoustic pressure and fluid velocity on the body, in the nearfield, and in the farfield are calculated. The acoustic fields of the quadrilateral elements are evaluated by certain expansions in wavenumber. The method is described and its usefulness and limitations discussed. The accuracy of the method is exhibited by comparisons with analytic solutions for a number of bodies including a sphere, a cube, a triaxial ellipsoid, and a finite circular cylinder.
Operator Singularities of Integral Equations of Linear Acoustics
Authors: Baylor J. L.
Published: November 2005

The harmonic potential which represents the field radiated from a closed surface is a solution of the reduced wave equation. On the radiating surface, the potential and its normal derivative are uniquely related by a surface integral equation. This integral equation is singular in the operator sense at the eigenvalues of the reduced wave equation for the zero potential surface condition. The way in which these operator singularities influence the analytical and numerical solution of the integral equation will be discussed. Analytical and numerical examples which illustrate the eigenvalue influence will be given.
Mechanical Vibration Transmission in the Mariner '69 Spacecraft
Authors: Scharton Terry D. , Yang Thomas M. , Trummel Marc C. , Mansour Momtaz N.
Published: November 2005

Statistical energy techniques are used to obtain an engineering estimate of the high-frequency mechanical vibration transmission in the Mariner '69 spacecraft assembly. The vibration transmission path involves the following elements: (1) the Cenatur tank dome, or alternatively, a vibration test fixture, (2) the spacecraft adapter, and (3) the spacecraft electronic assemblies. Analytical values of the acceleration transfer functions for these elements are compared with measured values obtained in development vibration tests of a structural-model spacecraft. The results of this comparison are used to refine the analysis techniques and to gain confidence for applying the techniques to other spacecraft structures. Plans to study the acoustical vibration transmission in the Mariner '69 are described.
SIC Rocket-Noise Effect on House Trailers
Authors: Sawyer G. Norman , Nybo L. W.
Published: November 2005

Criterion for noise-induced damage presently in use places major emphasis on window-glass breakage. The criterion sets noise levels at the frequency of the window resonance considering the window to be simply supported. In the case of light trailer construction, the effect of the wall driving the window should be considered. Measurements made on a house trailer exposed to the noise of the SATURN V's first stage booster, the 7 500 000 pound thrust SIC, static tested at NASA's Mississippi Test Facility, are presented.
Use of Constant-Bandwidth Narrow-Band Frequency Analysis to Pinpoint Noise Sources in Machinery
Authors: Lynch G. A. , Mitchell L. D.
Published: November 2005

This paper compares the results of the analysis of noise and vibration in machinery by constant-bandwidth filters as narrow as 2 cps with the more conventional octave-band, 13-oct band, and percentage-of-center-frequency filters. The nature and character of the resulting noise spectra are used to pinpoint machinery noise sources. The technique described involves instrumentation-quality tape recording of noise emanating from a machine, followed by analysis of the tape in the laboratory with narrow-band scanning filters and direct plotting of the results on X-Y plotters. In some studies, the interdependence of noise and vibration has been determined by simultaneously recording both signals and making an analysis. Comparisons between these narrow-band vibration and noise spectra give new insight into the dynamic behavior of machines.
A Method of Axial Testing for Roller Bearing Noise Qualities
Authors: Lucht R. F. , Scanlan R. H.
Published: November 2005

A number of investigators have studied the vibration of rolling element bearings by taking samples of bearing race vibratory velocity, acceleration, or displacement at one point on the race the bearing being run in a somewhat isolated enviroment. While such methods have lead to considerable progress in the evaluation and amelioration of bearing-generated noise, there has been a constant trend toward improvement of the methods. One promising step in this process is reported here. The present paper discusses the replacement of accelerometer radial testing by accelerometer axial testing, the new connecting link between bearing and accelerometer being a metallic exponential horn. The horn technique avoids problems of accelerometer strain sensitivity and dependence of results upon accelerometer angular orientation with respect to specific bearing anomalies.
Simulation of the Neural Response in the Peripheral Auditory System
Authors: Sakai H. , Ohgushi K.
Published: November 2005

Response area, inhibitory area, and the phenomenon of masking in the peripheral auditory system was simulated by computer model of the basilar membrane and the nervous connection. Assuming that the primary neuron provides the forward lateral inhibition and that the input signal to the primary neuron changes in proportion to the amplitude of the vibration of the basilar membrane, the internal potential of the neuron, n(x,f,I), is given by n(x,f,I) = A⋅g(x,f,I) − ΣA⋅g(x + NΔx,f,I)⋅wi(NΔx), where wi represents the distribution of the inhibition along x. If the threshold of the primary neuron is θ, the response area of the neuron corresponding to the distance x0 will be expressed by I = θ/A⋅{g(x0,f,1) − Σg(x0 + NΔz,f,1)⋅wi(NΔx)}. In the presence of the second stimulus, similarly, the inhibitory area of the neuron of which characteristic frequency is f1 will be represented by I2(f2) = {I1⋅n(x0,f1,1) − θ}/n(x0,f2,1). The computed results for these models agreed with the observations on the physiological experiments. In the case of masking, the intensity of the masked signal needed to exceed the threshold of the neuron corresponding to x0 will be represented by I1 = {θ − I2⋅n(x0,f2,1)}/n(x0,f1,1). This expresses the masking pattern in the primary neurons.
A Model for Auditory-Nerve Discharge Patterns of Mammals
Authors: Anderson David J. , Geisler C. Daniel
Published: November 2005

A model for the mammalian peripheral auditory system was implemented on the hybrid-computer facility of the University of Wisconsin. The important assumptions used are: (1) Fine terminal fibers from a short distance along the cochlear partition merge into a single auditory-nerve fiber. (2) Information is transmitted along each of the many terminal fibers in a discrete format. (3) Each terminal process recovers slowly after excitation. (4) The auditory-nerve fiber generates an output when only a small fraction of the peripheral fibers are active simultaneously except for a short refractory period when no output is possible. The model also has the characteristic of not requiring the addition of random noise to its excitatory process for the proper reproduction of data which has been most usefully observed in a statistical format. The model simulates single-spike data obtained from certain auditory-nerve fibers of Squirrel Monkey for low-frequency tone stimulation. Interval and folded histograms that have been used to describe data obtained by Rose et al. are matched as well as the spike-count versus stimulus-intensity relationships. [Work supported by NIH Predoctoral Fellowship.]
Discharge Characteristics of Binaurally Excited Neurons in Cat Inferior Colliculus
Authors: Geisler C. D. , Rhode W. S. , Hazelton D. W.
Published: November 2005

Single neurons in the barbiturized cat's inferior colliculus responding to binaural acoustic stimuli were monitored by platinum-iridium microelectrodes. Tones and bandpass noise were used as stimuli. Usually, the stimuli to each ear had identical waveforms but differing intensities, and one stimulus was delayed relative to the other. Results confirm and extend previous observations reported from this laboratory. Characteristics of responses obtained from different neurons differed so much that it was difficult to formulate response categories. Nevertheless, certain neurons were found to respond primarily to the intensity properties of the stimuli, while other neurons responded primarily to interaural time differences. In either cases, responses elicited by tones and by bands of noise had interesting differences: it was not possible to predict the characteristics of the responses to bandpass noise from the continuous-tone responses and vice versa. [This work was supported by NIH grant.]
Intraesophageal Pressure during Syllable Repetition
Authors: McGlone Robert E.
Published: November 2005

Intraesophageal pressure was investigated as a possible indirect indicator of subglottic pressure in a dynamic speech situation. Five male subjects repeated the syllable /pʌ/ at rates of 1/sec and 4/sec, for 4 sec. Balloon length, diameter, position in the esophagus, and volume of air in the balloon were systematically varied. Of interest was the magnitude of change in intraesophageal pressure values that occur during any trial and the repeatability of the pressure measures in relation to the various experimental factor combinations. It was found that intraesophageal pressure values varied as lung volume changed; increasing as lung volume decreased. Also, variability between repeated trials was so large that the technique of intraesophageal pressure measurement appeared not to yield useful data. Amplitude of the pressure pulses associated with syllables repeated once per second appeared to interact with base pressure; decreasing as base pressure increased. No pressure pulses were found associated with syllables repeated at the faster rate. The data suggest that intraesophageal pressure cannot be used as an index of subglottic pressure in dynamic speech situations.
Measurement of Coherence in Seawater Utilizing an Acoustic Analog of Young's Experiment
Authors: Lee J. V. , Brown D. H.
Published: November 2005

Acoustic coherence experiments have been performed in St. Andrews Bay, Florida. Phase and amplitude stability was measured in the far field of a highly directive barium titanate transducer array. Phase changes as small as 0.05° could be detected along a 7-m wavefront. The measurements were made at 200 kc/sec, depths to 7 m, and over a range of 35 m. Under typical operating conditions, the phase relation ships in the direct path and bottom bounce wavefronts were observed to be extremely stable. The results of these measurements are directly applicable in areas of interest such as: acoustic holography, the design of large-aperture synthetic or physical arrays, ultrasonic imaging, and wave propagation in random or turbulent media.
Computer Movies of Wavefront Motion
Authors: Sondhi M. M.
Published: November 2005

The motion of a wavefront in deep water can be quite complicated, owing to the variation of sound velocity with depth. To help visualize this motion, a digital computer was programmed to produce a movie of the wavefront motion for arbitrarily specified velocity variation and source position. Examples of such computer-generated movies for various velocity profiles are shown to illustrate the utility of the technique.
Fluctuation in Underwater Acoustic Propagation Over Short Depth Increments
Authors: Whitmarsh David C. , Leiss William J.
Published: November 2005

Underwater-acoustic-propagation measurements have been made off Key West, Florida periodically for the past 2 yr. Two or three deep-submergence vehicles were allowed to sink freely through the water to depths as great as 5000 ft while transponding acoustically with each other. Pulses at frequencies of 10, 20, and 40 kHz and ranges of 1700 to 4000 yd were used in the experiment. Because direct acoustic signals showed amplitude fluctuations of the order of 20 dB for depth changes 20–30 ft, a method of rapid pulsing was installed so that discrete signals 0.25 sec apart could be transmitted periodically for a period of 5 sec. This allowed a measure of the fluctuation for depth changes of only a few inches. Pulse-to-pulse amplitude differences of up to 10 dB were found for depth changes of as little as 10 in. These fluctuations are discussed in terms of transmission loss and are compared to the losses suffered for larger depth changes and those predicted by ray theory on the basis of the measured sound velocity structure of the water. [This research was supported by the U. S. Naval Ordinance Systems Command.]
Analysis of Short Pulse Echoes from Copper Plates
Authors: Weisser F. L. , Diercks K. J. , Evans W. E.
Published: November 2005

This study was an attempt to simulate the echo-locating signal of an Atlantic bottlenose dolphin, Tursiops truncatus, to generate echoes from targets known to be acoustically discriminable by an animal of this species. The targets were flat copper plates that varied in the thickness dimension only. An 0.22-cm thick plate was selected as reference; the animal was unable to discriminate an 0.16-cm-thick plate from the reference plate, but was able to discriminate 0.28 and 0.32-cm thick plates on 60% and 75% of the trials, respectively (Evans and Powell, “Discrimination of Different Metallic Plates by an Echolocating Delphinid,” Animal Sonar Systems, Proceedings of the Symposium on Bionic Models of the Animal Sonar System, Frascati, Italy, 26 Sept.–3 Oct. 1966). Echo waveforms and scattering patterns were recorded at 6-in. range increments from 14 in.–50 in. test ranges. Pulse repetition rates and signal levels similar to those of the animal were used. The scattered field was sampled using biaural hydrophones separated approximately the distance of the animal's receptors. Only monaural signal characteristics are reported here. Results of the analysis show power spectral density to be the most promising discriminant (target-specific) characteristic. Differences in scattered intensity are noted, but are slight. No obvious differences between echo waveforms from the different plates were observed. Correlations with the outgoing signal display discriminable peak values, which may be artifactual. [This work was supported by the Office of Naval Research.]
Sound Fields within Aquaria
Authors: Parvulescu Antares
Published: November 2005

Small aquaria are generally convenient for bioacoustic experiments. Sound introduced into such tanks is often measured with pressure-sensitive hydrophones. Unfortunately, sound in a small tank never propagates in a plane wave, and therefore pressure measurements can be highly misleading. The sound field also fails to resemble the natural acoustic environemnt of the organisms. We have obtained further measurements of the effective wall impedance and, hence, estimates of the wave impedance within such tanks, using the technique described at the Second Symposium on Marine Bio-Acoustics (1966). The fields within the tanks are similar whether the sound source is located in the water or in the air nearby. Particle velocities in the water (and hence displacements) are orders of magnitude greater than has been sometimes assumed from uncritical use of pressure hydrophones. This suggests that animal behavior may be due to lateral-line response rather than to auditory system response. [Hudson Lab. of Columbia Univ. Informal Documentation No. 148. This work was supported by the U. S. Office of Naval Research.]
Nonlinear Distortion in Dynamic, Direct Radiator, Loudspeakers
Authors: Olson Harry F.
Published: November 2005

The major contributors to nonlinear distortion in dynamic direct radiator loudspeakers are the driving and suspension elements. These elements are constant for small and moderate amplitudes but depart from constancy for large excursions of the cone and voice coil. A theoretical analysis shows that the major spurious components due to the nonlinear distortion are third harmonics of the fundamental. Means for reducing and canceling the nonlinear distortion due to the driving and suspension systems are described.
An Infrasonic Generator
Authors: Richie W. C. , Little C. P. , Evertson D. W.
Published: November 2005

An infrasonic generator utilizing a single bellows driven by a linear displacement transducer has been constructed. The generator has a dynamic range that extends from 0.5 dyn/cm9 to 600 dyn/cm2 and a frequency response of +0.5 dB, −0.6 dB from 0.001 Hz to 10 Hz. The infrasound generated by this device will be utilized for the study of the effects of infrasound on human beings. [This research is supported by National Science Foundation Grant 6K 1588].
Transducer Element Design for an Endfire Array
Authors: Miller Harry B.
Published: November 2005

In the design of resonant transducer elements for a high-power array steerable from broadside to endfire, some new design concepts and terminology have arisen such as velocity control, Zoc, etc. The new approach tends to avoid explicit use of such design parameters as coupling coefficient, mechanical Q, etc. [H. B. Miller, High Power Steerable Planar Array, JUA(USN) 14, 401 (April 1964)]. The question arises as to whether the new approach alone is sufficient for the designer.
Mechanical Stability of the Diaphragm of an Electrostatic Loudspeaker
Authors: Merhaut Josef
Published: November 2005

Mechanical stability of thin diaphragm in an electrostatic loudspeaker depends on the balance between the mechanical tension of the diaphragm and the electrostatic forces between it and the back electrodes. The condition of this balance as a function of the design parameters is calculated. The author shows in a push-pull electrostatic loudspeaker, that the requirements for mechanical stability and the lowest-frequency limit are contradictional. Futher, the formula for this frequency limit in connection with the condition of mechanical stability of the diaphragm is derived.
Measurement of the High Pressure Acoustic Properties of Various Transducer Materials
Authors: Higgs R. W.
Published: November 2005

An impedance tube technique is used to measure the acoustic propagation constants and characteristic impedance of various transducer materials as a function of hydrostatic stress and frequency. The materials measured function as reflectors, decouplers, absorbers and windows in the transducer assembly and the high-pressure properties are required to assure high operational efficiency and satisfactory directivity patterns in deep ocean operation. The pressure in these measurements is varied from 10 to 45 kHz. The acoustic measuring system is described and the characteristics of the materials are presented.
Noise Measurements During Take-Off and Climbout Operations of Jet Transports
Authors: Copeland W. Latham
Published: November 2005

Data were obtained under closely controlled conditions for both simulated and actual climbouts with the objective of correlating the operation of the aircraft with the measured noise. Two-, three- and four-engine commercial jet aircraft having turbojet and turbofan engines were included in the program. Good correlation was found between the ground noise measurements and such factors as flight profile, engine power, flap setting and aircraft speed. Parametric charts are included to illustrate the relative significance of the above variables and are shown to be useful for ground noise predictions.
Perceived Order of Tone Pulses
Authors: Peters Robert
Published: November 2005

Order of a series of tone pulses is perceived differently from actual order when frequency of the pulses vary. If the center pulse differs in frequency from the other pulses in a train, the center pulse is heard as either first or last in the series. Because this was observed when the frequency of a center pulse was adjusted for trains, the effect may have been a function of repetition. For this study, 12 subjects judged the order of pulses in trains presented in random order. There were three pulses in each train each of 20 msec duration with pulse intervals of 50 msec. The first and third pulses were 1000 Hz in all cases; the center pulse was varied in discrete steps from 400 to 2000 Hz. The data indicated that perceived order was controlled by frequency of the center pulse. For center pulse frequencies below 600 and above 1600 Hz the observers judged that the center pulse followed the other two pulses. [This work was supported by the U. S. Air Force under Contract No. AF 33 (615)-1181.]
Detection and Relative Discrimination of Auditory “Jitter.”
Authors: Pollack Irwin
Published: November 2005

Thresholds for the minimal departure from periodicity and thresholds for discrimination of relative departure from periodicity were obtained in order to explore the limits of temporal resolution for auditory pulse trains. In a forced-choice test, listeners were presented pulse trains, one of which was subjected to more variability, or jitter, than the other three. The principal experimental variables examined were: the number of intervals; the mean interpulse interval; and, the jitter of the reference pulse train. Minimum thresholds for jitter, relative to the center interpulse interval, is less than 0.1% for a large number of pulses. Threshold jitter decreases with shorter interpulse intervals for a large number of pulses. Jitter thresholds are minimal for interpulse intervals of 4–6 msec for a small number of pulses. Jitter discrimination is approximately independent of the reference jitter for a small number of pulses and is nearly directly proportional to the reference jitter for a large number of pulses. The temporal precision of the auditory system, in contrast with its precision of spectral analysis, appears insufficient to account for minimal jitter thresholds.
Identifying Meaningless Tonal Complexes
Authors: Webster J. C. , Carpenter Alan , Woonhead M. M.
Published: November 2005

Series of buzz tones with up to 24 harmonics were presented to five groups of listeners for identification. Nine tones in which different harmonics were emphasized were presented to Group I who could easily tell them apart and could identify them with 33% accuracy. The remaining groups heard three of the tones in various conditions of noise, filtering, fundamental frequency, and emphasized to nonemphasized harmonic intensity differentials. The most difficult task was to identify the tones with differing harmonic structure when the fundamental frequency was not the same for every complex tone. It was also difficult to pick out complexes with the same harmonic structure and basic frequency when noise-masked, filtered, and in-quiet items were intermixed at random in the same test. The distinguishing differences in the meaningless buzz complexes were in harmonics six and above.
Aural Harmonics: Tone-on-Tone Masking at Various intensities of the Fundamental
Authors: Clack T. D.
Published: November 2005

Aural harmonic distortion was produced in seven normal ears by presenting a 1000-Hz pure tone (f1) at 57, 61, 65, 67, 69, 71, and 74 dB SPL. Simultaneously, listeners traced a Békésy-type threshold for an objective 2000-Hz tone (f2) which was “phase shifted” through 360°. The variations in such tracings fit the equation; Y = A1+A2 sin (x+φ). The effect of the changes in f1 intensity upon the three dependent variables, A1, A2, and φ, will be analyzed separately. Results indicate that increases in the f1 intensity produce: (1) linear increases (slope≈2.0–2.5 dB) in A1, the over-all masking level; (2) a small but complex change in A2, the phase amplitude effect; and (3) no change in φ, the phase shift. These data will be interpreted in terms of a model that has three major assumptions: (a) the ear generates an aural harmonic (AH); (b) the objective f2 and the AH sum vectorially; (c) the listener must maintain the resultant sum at some perceptual threshold level.
In-Flight Spectrum Analysis of Random Waves
Authors: Coffin T. , Serocki J.
Published: November 2005

Direct transmission of wide-band spacecraft data places an inordinate burden on the available telemetry spectrum. It is extremely advantageous from the standpoint of telemetry spectrum economy to process measurements onboard and transmit the reduced data over a narrow-bandwidth telemetry channel. This paper describes a random wave analyzer for inflight processing of vibration and acoustic data. Development considerations are discussed and an evaluation of instrumentation concepts presented. A functional description of the technique selected for implementation is presented. The technique may be described as an incremental constant bandwidth analyzer, since three synchronized sweeping filters are utilized to produce a spectrum with differing resolution in separate frequency increments. Typical analysis times range from 1 to 8 sec. Sweep rates, averaging times, and frequency increments are adjustable, providing maximum flexibility. An evaluation of the analyzer is summarized and spectral estimates compared with those obtained by a laboratory quality wave analyzer. Physical characteristics of a six channel prototype system are described. [Sponsored by NASA Manned Spacecraft Center.]
Acoustical Impedance of Thin Diaphragms
Authors: Merhaut Josef
Published: November 2005

Differential equation describing the deflection η of a thin circular diaphragm, loaded with a complex specific acoustical impedance per unit area is solved. Then the total acoustical impedance Za of the diaphragm defined by 1/Za = jω∫∫ηdS/p is calculated, where p is the acoustic pressure, and dS element of area. After expanding the Bessel functions in the result into series, zeroes and poles of Za are found. Further, a complete analog network for a thin diaphragm is given, including the formulas for the elements of this network.
An Underwater-Sound Level Meter
Authors: Truchard J. J.
Published: November 2005

The design of an audio-frequency underwater-sound level meter is presented. It consists of a hydrophone, low-noise preamplifiers, and a true rms voltmeter. The hydrophone consists of two ceramic hemispherical shells cemented together with an especially designed 40-dB gain preamplifier inside the hemispheres. The use of a preamplifier inside the ceramic element permits the use of short leads between the ceramic and the preamplifier without a separate preamplifier housing. The self-noise level of the preamplifier is more than 20 dB below the noise level equivalent to sea state zero at frequencies up to 1000 Hz. The thermal noise of the hydrophone is compared to the theoretical thermal-noise limit of a unit-efficiency, omnidirectional hydrophone. The square-law detector in the true rms meter circuit uses a field-effect transistor for squaring. The frequency range of the underwater-sound level meter is 20–20 000 Hz. All components except the hydrophone are useful to 100 kHz. The underwater-sound level meter was used to measure the noise level under extremely quiet conditions in an anechoic Mason tank. The noise levels measured were as low as 17 dB below equivalent sea-state-zero noise at 1000 Hz. [This work was sponsored by the U. S. Naval Ship Systems Command.]
MULTI-STEP MAGNETIZATION INDUCED BY THE FIELD AND THERMAL EFFECT IN THE PHASE-SEPARATED Pr2/3Ca1/3MnO3 MANGANITES
Authors: SHA YANNAN , ZHANG JINCANG , CAO GUIXIN , YAO KAI , JING CHAO , CAO SHIXUN
Published: November 2005

The multi-step transition by the field inducement is reported in pristine Pr 2/3 Ca 1/3- MnO 3 manganites. This step effect shows a strong dependence on the temperature and field sweep rate, which is sensitive to thermal perturbation. The results prove that they are related with the internal magnetic structure of phase-separated Pr 2/3 Ca 1/3 MnO 3 manganites in low temperatures, while the influence of sweep rate can be accounted for within a martensitic-like scenario.
DETECTION OF INERT GASES BY COLD ELECTRON EMISSION FROM CARBON NANOTUBE EMITTERS
Authors: KIM SEONGJEEN
Published: November 2005

In this work, different from the typical gas sensors responding by gas adsorption on their surface, a new gas sensor using carbon nanotubes (CNTs) as electron emitters is introduced for detecting inert gases which hardly possess chemical or electrical adsorption in normal conditions. The proposed sensor works by figuring out the variation of the dark current and the initial breakdown voltage on Paschen's law under applied high voltage. As they depend on the gas composition and the pressure in a sealed chamber, it is possible to detect the identity and the concentration of unknown inert gas species.
SPATIAL ROTATION DRIVEN BY RANDOM ANGULAR VELOCITY (COLORED NOISE)
Authors: GUZ SERGEY A. , SVIRIDOV MICHAEL V.
Published: November 2005

We consider kinematics of a rigid body rotation about a fixed point. An angular velocity is considered to be a sum of deterministic and random vector-functions. We suppose that the components of the latter are statistically independent small stationary processes. The problem is, for example, important for the theory of a rotational Brownian motion or an error analysis of strapped-down inertial navigation systems. We construct a multiplicative perturbation theory so that the desired matrix is represented as a product of deterministic matrix by random perturbation one. The perturbation matrix is approximately found by the first terms of a matrizant. As example, we consider the constant deterministic velocity and the components of the colored random velocity to be white noises (the Brownian motion), the Ornstein-Uhlenbeck processes, or the time derivative of the Ornstein-Uhlenbeck processes ("green" noises). In the second case it is shown that a diffusion of an instanta-neous rotation angle appears only if the deterministic rotation is not zero.
Computing transitive closures of multilevel relations
Authors: Thuraisingham Bhavani
Published: November 2005

Recently many attempts have been made to implement recursive queries. Such queries are essential for the new generation intelligent database system applications. Much of the effort in recursive queries is focussed on transitive closure queries which are of practical significance. None of the work described investigates recursive query processing in secure database management systems. In this paper we propose centralized and distributed algorithms for implementing transitive closure queries for multilevel secure relational database management systems.
Yet another note on minimal covers
Authors: Nummenmaa Jyrki , Thanisch Peter
Published: November 2005

In [Atk88] Atkins corrects a widely spread error in the algorithm for finding a minimal cover for a given set of functional dependencies. The erroneous form of the algorithm has been presented in [Sa186,StW83,Ul182,Yan88]. Unfortunately, though, there is an error also in the corrected algorithm.

Atkins proposed the following algorithm for determining a minimal cover for a given set of functional dependencies
F
.
Using reasoning to guide annotation with gene ontology terms in GOAT
Authors: Bada Michael , Turi Daniele , McEntire Robin , Stevens Robert
Published: November 2005

High-quality annotation of biological data is central to bioinformatics. Annotation using terms from ontologies provides reliable computational access to data. The Gene Ontology (GO), a structured controlled vocabulary of nearly 17,000 terms, is becoming the
de facto
standard for describing the functionality of gene products. Many prominent biomedical databases use GO as a source of terms for functional annotation of their gene-product entries to promote consistent querying and interoperability. However, current annotation editors do not constrain the choice of GO terms users may enter for a given gene product, potentially resulting in an inconsistent or even nonsensical description. Furthermore, the process of annotation is largely an unguided one in which the user must wade through large GO subtrees in search of terms. Relying upon a reasoner loaded with a DAML+OIL version of GO and an instance store of mined GO-term-to-GO-term associations, GOAT aims to aid the user in the annotation of gene products with GO terms by displaying those field values that are most likely to be appropriate based on previously entered terms. This can result in a reduction in biologically inconsistent combinations of GO terms and a less tedious annotation process on the part of the user.
The GenAlg project
Authors: Hammer Joachim , Schneider Markus
Published: November 2005

Life scientists are faced with a rapidly increasing accumulation of data stored in large
genomic repositories
like EMBL, GenBank, SwissProt, and DDBJ, to name a few. The flood of genomic data, their high variety and heterogeneity in semantics, formats and access methods, their semi-structured nature, and the increasing complexity of biological applications and methods mean that many and very important challenges in biology are now challenges in computing.
BioFast
Authors: Bleiholder Jens , Naumann Felix , Lacroix Zoé , Raschid Louiqa , Murthy Hyma , Vidal Maria-Esther
Published: November 2005

An abundance of life sciences data sources contain data about scientific entities such as genes and sequences. Scientists are interested in exploring relationships between scientific objects, e.g., between genes and bibliographic citations. A scientist may choose the OMIM source, which contains information related to human genetic diseases, as a starting point for her exploration, and wish to eventually retrieve all related citations from the PUBMED source. Starting with a keyword search on a certain disease, she can explore all possible relationships between genes in OMIM and citations in PUBMED. This corresponds to the following query:
"Return all citations of
PUBMED
that are linked to an
OMIM
entry that is related to some disease or condition."
An early look at XQuery API for Java™ (XQJ)
Authors: Eisenberg Andrew , Melton Jim
Published: November 2005

In Feb. 2004, the period for submitting Last Call Working Draft comments for most parts of the XQuery specification came to a close. While there is still a great deal of work to be done to make XQuery a W3C Recommendation, the documents have become more stable with each public release. In this column we'd like to provide an initial look at the XQuery API for Java™ (XQJ), a project that is taking place within the Java Community Process (JCP).
Review of "Managing gigabytes: compressing and indexing documents and images, by Ian H. Witten, Alistair Moffat, and Timothy C. Bell" Morgan Kauffman, 1999, 519 pp. ISBN 1558605703.
Authors: Nagaraj S. V.
Published: November 2005

This book published in 1999 is a revised second edition of the version that first appeared in 1994. The authors have incorporated many changes in the second edition by updating various chapters to include the latest developments. The book is concerned with the task of managing large volumes of text and image data amounting to several gigabytes. The fundamental problems addressed in the book include compressing such data and indexing it, in order to enable easy search. Many books look at compressing and indexing as if they are unrelated techniques; however, this book brings out the advantages of combining them in a beneficial way.
Characterizing a software process maturity model for small organizations
Authors: Saiedian Hossein , Carr Natsu
Published: November 2005

Software process refers to the set of tools, methods, and practices used to produce a software artifact. The objective of a software process management model is to produce software artifacts according to plans while simultaneously improving the organization's capability to produce better artifacts. The SEI's Capability Maturity Model (CMM) is a software process management model; it assists organizations to provide the infrastructure for achieving a disciplined and mature software process. There is a growing concern that the CMM is not applicable to small firms because it requires a huge investment. In fact, detailed studies of the CMM show that its applications may cost well over $100,000. This article attempts to address the above concern by studying the feasibility of a scaled-down version of the CMM for use in small software firms. The logic for a scaled-down CMM is that the same quantitative quality control principles that work for larger projects can be scaled-down and adopted for smaller ones. Both the CMM and the Personal Software Process (PSP) are briefly described and are used as basis.
Semantically enriched web services for the travel industry
Authors: Dogac A. , Kabak Y. , Laleci G. , Sinir S. , Yildiz A. , Kirbas S. , Gurcan Y.
Published: November 2005

Today, the travel information services are dominantly provided by Global Distribution Systems (GDS). The Global Distribution Systems provide access to real time availability and price information for flights, hotels and car rental companies. However GDSs have legacy architectures with private networks, specialized hardware, limited speed and search capabilities. Furthermore, being legacy systems, it is very difficult to interoperate them with other systems and data sources. For these reasons, Web service technology is an ideal fit for travel information systems.

However to be able to exploit Web services to their full potential, it is necessary to introduce semantics. Without describing the semantics of Web services we are looking for, it is difficult to find them in an automated way and if we cannot describe the service we have, the probability that people will find it in an automated way is low. Furthermore, to make the semantics machine processable and interoperable, we need to describe domain knowledge through standard ontology languages.

In this paper, we describe how to deploy semantically enriched travel Web services and how to exploit semantics through Web service registries. We also address the need to use the semantics in discovering both Web services and Web service registries through peer-to-peer technology.
Report on the 3rd web dynamics workshop, at WWW'2004
Authors: Levene Mark , Poulovassilis Alexandra
Published: November 2005

The web is highly dynamic in both the content and quantity of the information that it encompasses. In order to fully exploit its enormous potential as a global repository of information, we need to understand how its size, topology, and content are evolving. This then allows the development of new techniques for locating and retrieving information that are better able to adapt and scale to its change and growth. The web's users are highly diverse and can access the it from a variety of devices and interfaces, at different places and times, and for varying purposes. Thus, new techniques are being developed for personalising the presentation and content of web-based information depending on how it is being accessed and on the individual user's requirements and preferences. New applications in areas such as e-business, sensor networks, and mobile and ubiquitous computing need to be able to detect and react quickly to events and changes in web-based information. Traditional approaches using query-based `pull' of information to find out if events or changes of interest have occurred may not be able to scale to the quantity and frequency of events and changes being generated, and new `push'-based techniques are being deployed in which information producers automatically notify consumers when events or changes of interest to them occur. Semantic Web and Web Service technologies are being developed and adopted, with the aim of providing standard ways for web-based applications to share and personalise information.
A holistic paradigm for large scale schema matching
Authors: He Bin , Chang Kevin Chen-Chuan
Published: November 2005

Schema matching is a critical problem for integrating heterogeneous information sources. Traditionally, the problem of matching multiple schemas has essentially relied on finding pairwise-attribute correspondences in isolation. In contrast, we propose a new matching paradigm,
holistic schema matching
, to match many schemas at the same time and find all matchings at once. By handling a set of schemas together, we can explore their
context
information that reflects the semantic correspondences among attributes. Such information is not available when schemas are matched only in pairs. As the realizations of holistic schema matching, we develop two alternative approaches:
global evaluation
and
local evaluation
. Global evaluation exhaustively assesses all possible "models," where a
model
expresses all attribute matchings. In particular, we propose the MGS framework for such global evaluation, building upon the hypothesis of the existence of a hidden schema model that probabilistically generates the schemas we observed. On the other hand, local evaluation independently assesses every single matching to incrementally construct such a model. In particular, we develop the DCM framework for local evaluation, building upon the observation that co-occurrence patterns across schemas often reveal the complex relationships of attributes. We apply our approaches to match query interfaces on the deep Web. The result shows the effectiveness of both the MGS and DCM approaches, which together demonstrate the promise of holistic schema matching.
Kanata
Authors: Andritsos Periklis , Fuxman Ariel , Kementsietsidis Anastasios , Miller Renée J. , Velegrakis Yannis
Published: November 2005

In Toronto's Kanata project, we are investigating the integration and exchange of data and metadata in dynamic, autonomous environments. Our focus is on the development and maintenance of semantic mappings that permit runtime sharing of information.
From semantic integration to semantics management
Authors: Rosenthal Arnon , Seligman Len , Renner Scott
Published: November 2005

For meaningful information exchange or integration, providers and consumers need compatible semantics between source and target systems. It is widely recognized that achieving this semantic integration is very costly. Nearly all the published research concerns how system integrators can discover and exploit semantic knowledge in order to better share data among the systems they already have. This research is very important, but to make the greatest impact, we must go beyond after-the-fact semantic integration among existing systems, to actively guiding semantic choices in new ontologies and systems - e.g., what concepts should be used as descriptive vocabularies for existing data, or as definitions for newly built systems. The goal is to ease data sharing for both new and old systems, to ensure that needed data is actually collected, and to maximize over time the business value of an enterprise's information systems.
Ontologies and semantics for seamless connectivity
Authors: Uschold Michael , Gruninger Michael
Published: November 2005

The goal of having networks of seamlessly connected people, software agents and IT systems remains elusive. Early integration efforts focused on connectivity at the physical and syntactic layers. Great strides were made; there are many commercial tools available, for example to assist with enterprise application integration. It is now recognized that physical and syntactic connectivity is not adequate. A variety of research systems have been developed addressing some of the semantic issues. In this paper, we argue that ontologies in particular and semantics-based technologies in general will play a key role in achieving seamless connectivity. We give a detailed introduction to ontologies, summarize the current state of the art for applying ontologies to achieve semantic connectivity and highlight some key challenges.
Semantic integration
Authors: Noy Natalya F.
Published: November 2005

Semantic integration is an active area of research in several disciplines, such as databases, information-integration, and ontologies. This paper provides a brief survey of the approaches to semantic integration developed by researchers in the ontology community. We focus on the approaches that differentiate the ontology research from other related areas. The goal of the paper is to provide a reader who may not be very familiar with ontology research with introduction to major themes in this research and with pointers to different research projects. We discuss techniques for finding correspondences between ontologies, declarative ways of representing these correspondences, and use of these correspondences in various semantic-integration tasks
UbiData
Authors: Helal Abdelsalam , Hammer Joachim
Published: November 2005

Mobile users today demand ubiquitous access to their data from any mobile device and under variable connection quality. We refer to this requirement as
any-time, any-where
data access whose realization requires much more support for asynchronous and disconnected operation than is currently available from existing research prototypes or commercial products. Furthermore, the proliferation of mobile devices and applications, forges the additional requirement of device- and application-transparent data access. Support for such
any-device, any-application
computing paradigm requires the ability to store and manage data in a generic representation and to transform it for usage in different applications, which may also be running on different platforms. In this article, we give an overview of the UbiData architecture and prototype system and show how it addresses these challenging requirements. We also summarize our ongoing and future efforts.
Report on the first "XQuery Implementation, Experience and Perspectives" workshop (XIME-P)
Authors: Manolescu Ioana , Papakonstantinou Yannis
Published: November 2005

The XQuery Implementation, Experience and Perspectives (XIME-P) workshop was organized by Ioana Manolescu and Yannis Papakonstantinou in cooperation with the ACM SIGMOD Conference, and was held in Maison de la Chimie, in Paris, France, on June 17 and 18, 2004. This report summarizes the goals and topics of the workshop, presents the major workshop highlights and the main issues discussed during the workshop.
Stonebraker receives IEEE John von Neumann Medal
Authors: DeWitt David , Carey Michael , Hellerstein Joseph M.
Published: November 2005

In December 2004, Michael Stonebraker was selected to receive the 2005 IEEE John von Neumann Medal for his
"contributions to the design, implementation, and commercialization of relational and object-relational database systems."
Mike is the first person from the database field selected to receive this award. He joins an illustrious group of former recipients, including Barbara Liskov (2004), Alfred Aho (2003), Ole-Johan Dahl and Kristen Nygaard (2002), Butler Lampson (2001), John Hennessy and David Patterson (2000), Douglas Engelbart (1999), Ivan Sutherland (1998), Maurice Wilkes (1997), Carver Mead (1996), Donald Knuth (1995), John Cocke (1994), Fred Brooks (1993), and Gordon Bell (1992).
No pane, no gain
Authors: Li Jin , Maier David , Tufte Kristin , Papadimos Vassilis , Tucker Peter A.
Published: November 2005

Windows queries are proving essential to data-stream processing. In this paper, we present an approach for evaluating
sliding-window
aggregate queries that reduces both space and computation time for query execution. Our approach divides overlapping windows into disjoint
panes,
computes sub-aggregates over each pane, and "rolls up" the pane-aggregates to computer window-aggregates. Our experimental study shows that using panes has significant performance benefits.