bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Geophysical Data Acquisition System for Marine Use
Authors: Ligon Jerry L. , Haill Harry K. 
Published: October 2008

ABSTRACT
A minicomputer-oriented geophysical data acquisition system has been developed which offers simplified system operation, instantaneous floating point capability, and provisions for real-time quality control. The computer performs all routine tasks with the operator interacting only to begin or modify major functions. The system is designed to fully utilize the precision capability of the floating point format in both its acquisition and processing capacity. Special features allow quality control to be applied to the data during acquisition.

INTRODUCTION
A geophysical seismic data acquisition system has been developed which simplifies data collection while monitoring data integrity and which allows full precision on-site processing. This advanced system brings the digital recording format, including instantaneous floating point amplification, together with a minicomputer to provide improvement in data handling and flexibility over conventional systems. In brief, the most interesting features of this system which will be discussed aresimplified system operation and control,full precision instantaneous floating point capability, andquality control.
Having a minicomputer integrated into the acquisition system allows simplified set-up and operation of the entire system. Communication with the system by the operator is accomplished exclusively through the keyboard and display of a CRT terminal. The display terminal is used in either of two modes by the operator, monitor or interactive. As a monitor, the system can provide an immediate display of operational parameters or system conditions. As an interactive device, the system can guide the operator through desired changes in operating parameters within limits set by the system.
The full floating point amplification and the ability of the system to deal with this form of data with full precision is of course important. There are several significant advantages offered by instantaneous floating point data. A system using this data will not Boon become obsolete. The technique gives a wide dynamic range (174 db in this case). Large changes in amplitude can occur without amplifier distortion. Also, small signal resolution is improved. Measuring accuracy is constant due to the A/D converter being operated within a restricted range of voltage input. The floating point technique also requires no manual control or settings.
Quality control is easily applied with this type of system. There are several ways quality of data is insured. One way is by making available results of instrument tests quickly and in hard copy form. Also, continuous quality control of data as it is acquired is applied before it is recorded. Data quality is further improved due to the wide range of data processing that can be performed by the system which was previously done only at distant processing centers.
Sosie Uses a Pulse Coding System to Improve Marine Seismic Records
Authors: Barbier Maurice G. , Viallix Jean R. 
Published: October 2008

ABSTRACT
An ever-increasing multiplication of transmission and reception points has been sought in reflection seismology, resulting in a better quality of the seismic sections. A limit has been reached, however, because no energy can-be transmitted during reception time. Sosie break this bottleneck in marine work by transmitting a continuous sequence of pulses at an average rate of about two pulses per second. If the pulse instants make up a successful designed code, a simple process can bring the returns back into their proper position.
The method can be implemented with any source, as long as its transmission rate is high enough, used as a single unit or alternately with other units of the same type. At the present time, sparkers and steam or air guns have been tested.
The implementation does not undergo drastic changes compared to the conventional method. The only additional piece of equipment is a coding-decoding device that, on the one hand, delivers the firing orders to the sources at prerecorded instants and, on the other hand, processes a trace to yield a single section for a check and preliminary interpretation on board. The best results are obtained when transmission and reception never stop.
Comparison sections demonstrate the advantages of the new process in shallow, normal and very deep water.

INTRODUCTION
Continuous improvements have been effected in reflection seismology at sea, resulting inmultiplication of transmission and reception points,increased order of coverage andintroduction of sources with controlled transmission.
The Sosie process takes maximum advantage of all these improvements. It is not a new source, but a better way of using existing sources provided they are capable of firing at least two to three times a second. The recorded data are a mixture of information coming from all depths, but it is easy at processing time to put everything back into position if the shooting instants are known accurately and if these instants make up a pseudorandom code.
The principle of Sasie was explained in some detail at the SEG meeting in New Orleans, and only a brief description of it will be made here. This paper will present the know-how that has been gained on implementation in the field, the processing and the presentation of recently shot comparison sections.

BRIEF DESCRIPTION OF THE PRINCIPLE
Sosie makes use of a coded sequence of discrete seismic pulses that have the same sign and essentially the same amplitude. The energy is released along the seismic profile according to the sequence, and seismic signal and transmission instants are recorded continuously.
Under these conditions, if we call y (t) the time function representing the code and S (t) each seismic pulse released, we transmit S (t) convolved with y (t) (Fig. 1).
Utillizing the Capabilities of Doppler Sonar to Solve the Navigating Problem
Authors: Jones Howard P. 
Published: October 2008

ABSTRACT
Doppler Sonar, although a unique and self contained means of navigation, saw limited acceptance until Edo Western Corporation realized that a real need existed for such a system. Edo Western Corporation invested in an extensive research and development program to advance the system capabilities over those systems which were already being marketed. The results of this program can readily be observed in the Model 435 Series of Doppler Navigation Systems. This system possesses greater "over-the-bottom" depth capability than any competitive system, will operate in shallower depths than any competitive system, and has a greater low velocity sensing and updating capability than any competitive system, just to highlight a few features.
Now with these capabilities, the question still arises as to how this system might best be utilized to help solve the many navigation problems.
The modular building block concept of the Edo Model 435 Series of Doppler Sonars provides a selection of optional hardware which can be selected to provide inputs to a satellite navigation receiver computer system or total system navigation capability utilizing a gyro compass may be provided completely within the Doppler Sonar. In addition, the operating depth range over the bottom may be extended to ranges heretofore unattainable by selection of available modules. All of these features make the Model 435 Doppler Sonar series capable of providing solution to virtually any navigation requirement.

INTRODUCTION
Many new instruments and techniques have been developed in recent years for use in researching the vast world of the oceans. Increased interest in utilizing ocean resources has led to significant growth in ocean exploration; hence an increasing need for development of new and improved methods for ocean navigation. Increasing sophistication in the fields of geophysical exploration, commercial shipping, and research for marine fishery sources has now made the use of precise navigation systems a necessity.
This paper has been prepared to assist in acquainting those unfamiliar with doppler sonar as to the various types and the ways in which they may be used. Once an individual understands the basic operation and capabilities of Doppler Sonar, many other applications can readily be seen.
Doppler sonar systems provide a self-contained means of navigation which does not depend on shore based stations or any other contact. The doppler sonar is capable of operating at any time of the day or night, regardless of weather conditions; therefore, it represents an extremely useful means of navigation for most types of ships. One of the primary uses of a navigation sonar is in geophysical survey work where precise location is required at all times. The doppler sonar has been integrated into complete Satellite Navigation Systems to provide a continuous, real time input of ships velocity to the navigation computer.
State-Variable Feedback Compensation of Acoustic Transducers
Authors: Newman A.K. 
Published: October 2008

ABSTRACT
Piezoelectric and electromagnetic acoustic transducers may be mathematically described by the state variable formalism well known in control theory, so that the powerful synthesis methods available in that discipline may be applied. Three transducer applications are considered. Each situation results in the standard ABC D matrix differential equation. The three equations are both completely controllable and completely observable. Therefore, general state-variable feedback is possible.
The well known Kalman observer1 is employed to obtain the internal state variables of the transducers. The Kalman observer is different for each transducer model, but it is an analog or digital computer that operates on the transducer input and an electrical transducer output that is part of the circuitry associated with the transducer for the production of an electrical output in addition to the acoustic output. The additional electrical output is critical to the compensation design. Once the internal transducer state variables are available, state-variable feedback may be used to arbitrarily place the closed-loop transducer poles. Reference is also made to a different approach using Luenberger observers,2 which allows a general compensation to be made by using only RC lag networks in a clever ladder array.
As long as the transducers are operated in the linear region, they may be compensated to have a transient response arbitrarily sharp to a pulse wave shape without ringing, as well as a very wide-band frequency response with very little phase shift. The Q and resonant frequency are, thus, also arbitrarily designable.
The compensation scheme may be compared to the well known negative damping factor or variable damping-factor idea used in some high fidelity power amplifiers that provide a variable adjustment on the effective internal impedance, even to the extent of obtaining a negative internal impedance. This new compensation scheme is able to provide an effective negative source resistance also, but the flexibility is extended to allow the designer to place negative mass, viscous damping, spring stiffness, resistance, capacitance, and negative inductance in desired places in the transducer equivalent circuit.
However, large input power is required for a design that places the closed-loop poles far in the left half plane; and such large power may drive the transducer into saturation, which would violate the design assumption of transducer linearity.
Further research is being conducted that will extend these results to nonlinear transducer models and allow the transducer to be driven nonlinearly so the net output is linear up to saturation and the distortion is drastically reduced.

INTRODUCTION
The history of acoustics is replete with methods for the improvement of acoustic response from transducers for microphones, loudspeakers and other transmitters.
Pore-Space Reduction in Sandstone - Controlling Factors and Some engineering Implication
Authors: Rittenhouse Gordon 
Published: October 2008

ABSTRACT
The average porosity of Gulf Coast Tertiary sandstones commonly decreases more than 1 percent for each 1,000 f't of' burial. This reduction results from a combination ofgrain rearrangement,pore filling with crystalline material andphysical and/or chemical modification of the original sand grains.
Factors controlling grain modification aresand composition,fluid composition and movement,effective stress,temperature,time and the extent to which early pore filling has strengthened the rock.
Pore filling reduces only the pore space; grain rearrangement and grain modification, in contrast, reduce both porosity and thickness of the sandstone.
Of particular concern here is that reduction of reservoir pressure during production increases the effective stress. Reducing reservoir pressure from 4,000 to 1,500 psi, for example, would have the same effect as burying a sand and its associated shales an additional 5,375 ft or more. As a result, the sand thickness could be reduced by as much as 9.4 percent, unless pore filling or prior deeper burial enables it to withstand the increased effective stress. This would be in addition to the consolidation of the associated shales that may occur more slowly and be of greater or lesser extent.
An understanding of factors controlling pore-space reduction and determination of their probable relative importance in specific cases may be helpful in anticipating such problems as casing failure or subsidence of' platform relative to sea level.

INTRODUCTION
When deposited, well-sorted sands commonly have porosities that exceed 38 to 42 percent and may exceed 50 percent. After burial and post depositional modification, sandstones of comparable grain size and sorting usually have much less porosity - in some cases, 1 percent or less. It is the purpose of this paper to discuss the factors and processes involved in such pore-space reduction and to consider some engineering implications, particularly when pore space reduction is accompanied by reduction in rock volume. Such reduction in rock volume is commonly referred to as compaction by geologists and as consolidation by engineers.
Knowing what has happened to sands in the past, and Why, can be significant in predicting what will happen if stress or other conditions are modified by man's activities. Has the sand been more deeply buried than at present, or was pore filling early? If so, an increase in stress may have little or no effect; if not, volume reduction may result. How may the original composition of sands and the type and extent of their post depositional modification affect selection of samples for engineering tests? Before considering these and other problems an understanding of the factors controlling pore space reduction is necessary.
Fatigue Strength Of Welded Tubular Joints With Various Stiffeners In Offshore Structures
Authors: Teramoto Susumu , Matoba Masaaki , Kawasaki Tetsuro 
Published: October 2008

ABSTRACT
This is a report of experiments and analyses made in a study on fatigue strength of tee and lambda types of pipe-pipe joints which are generally used for column stabilized drilling units or drilling platforms. The objective of this paper is to present a fundamental guidance and data to the designers engaged in this field by offering the fatigue strength of such joints under complicated stress and to find' the most effective type of joint.
There are many types of offshore structures to satisfy their various restricted service conditions. The fatigue strength is one of the important factors in strength of the structure under actual load. That is because safety and reliability during the useful service life of the structure are governed by its capability of registing against fractures (such as fatigue crack, brittle fracture, plastic collapse, buckling, etc.).
It may be assumed that the fatigue strength and its behavior of the pipe-pipe joints are particularly influenced by the factors of the structure design such as geometrical configuration and intersecting angle, reinforcement method and brace to chord radius ratio, as well as production process factors such as material, weldability, brace-chord fabrication, in addition to environmental factors (1-3).
In this study we have carried out the static and fatigue tests with regard to the above factors of structure design by using 22 typical scaled models (chord dia. 400 mmp) consisting of 8 different types of pipe-pipe joints in which the brace directly intersects the chord.

INTRODUCTION
Along with the recent tendency for more advanced ocean development, the ocean technology has been also developed to build off-shore structures capable of being operated under severer conditions. As is well known, various column stabilized drilling units and drilling platforms are now under operation, which have many problems of local structure strength resulting from the restrictions in their service conditions. These problems must be solved for further development of any new type of structure in the future.
Characteristics of these offshore structures are that large diameter pipes are used in full extent, forming a type of trussed Rahmen structure (Fig. 1). The joint structure of pipe members are decided taking various factors into consideration synthetically such as strength, member arrangement, hydro dynamical stability, weldability and fabrication, etc. For the purpose of applying the fatigue strength concept to the design of offshore structures, analysis of actual load (wave induced force involving dynamic pressure, tidal current) and the responses of the structure to these loads turn to be essential conditions (4).
It is an urgent problem to study the characteristics of fatigue strength of the joint of structural members, and rind its design procedure.
Automated Forecasting of Extratropical Storm Surges for the Northeast Coast of the United States
Authors: Pore N. Arthur 
Published: October 2008

ABSTRACT
The National Weather Service has developed an automated technique for forecasting extratropical storm surges along the northeast coast of the U.S. The storm surge is the rise of water level above the normal tide and is caused mainly by the strong winds associated with extratropical storms over nearshore areas.
Empirical forecast equations have been derived for 10 locations from Portland, Me., to Norfolk, Va. The equations were derived using data from 68 storms that occurred from 1956 through 1969. Input data to these forecast equations are sea-level pressure values as forecast by the numerical weather model of the National Meteorological Center. A sample forecast equation is shown.
The forecast method was put into operation in Oct., 1971, on an experimental basis. Forecasts are transmitted via teletypewriter and consist of values projected out to 48 hours at 6-hour intervals. These projections are used by Weather Service forecasters as guidance in preparing actual storm surge forecasts. A sample teletype message is shown.
Forecasts of the devastating storm surge of Feb. 19, 1972, are discussed. Forecast charts of sea-level pressure are compared to sea-level pressure analyses, and storm surge forecasts are compared to observed storm surges. Experience so far has emphasized the extreme importance, of the input sea-level pressure forecasts. Indications are that the system is useful and will be expanded to include other locations.

INTRODUCTION
The coastal storm of March, 1962, affected the entire Atlantic Coast of the U.S. and produced record-breaking high tides at some locations. This storm was the most devastating storm on record, as it caused damage estimated at over $200 million. Figs. 1 and 2 show some of the damage at Virginia Beach, Va., and Rehoboth Beach, Del.
It is, of course, extremely important to forecast the flooding associated with such storms. The critical time to forecast such conditions is also the time when forecasters are burdened with the usual bad weather conditions associated with coastal storms, such as extensive areas of rain or snow. The main purpose of automating the method is to produce better storm surge forecasts by providing guidance forecasts to Weather Service forecast offices.

CHARA.CTERISTICS OF THE EXTRA.TROPICAL STORM SURGE
Storm surge is defined as the meteorological effect on sea level and is computed as the algebraic difference between the observed tide and the normal astronomical tide. Fig. 3 illustrates this definition with a 2 day length of tide record. Here the observed tide is showy by the upper solid curve, the normal (or predicted) astronomical tide by the dashed line, and the storm surge by the lower curve.
Forecasting and Hindcasting the Maximum Combined Sea In Storms
Authors: Golaman Joseph L. , Bujnoch John A. 
Published: October 2008

1. Abstract
Forecasts of wind, waves and swells were made for a particular offshore operations area in the North Atlantic with accuracies of up to 97%.
The operational forecast system, using a dynamic model, is sensitive to accurate measurements of wind velocity and the combined sea at the verification site. Some of the waves forecast with the system were "twenty year waves", that occurred more than once in four years, so that a statistical forecast system could not possibly have been used to anticipate them. The system uses the moving storm as the center of coordinates with as many details of the wind field as can be applied directly through measurement or indirectly through physical principles of the atmosphere in mesoscale.
A simple circular storm model made from actual data for each case studied has resulted in hindcast accuracies never before achieved. This is shown to be a result of detailed wind information. The importance of detailed wind information for both forecasting and hindcasting cannot be overemphasized.

2. Introduction
The Institute for Storm Research is responsible for forecasting the state of the sea, on a daily basis for specific clients with specific needs. A working system is utilized which not only accounts for the known parameters but also satisfies "real time" prediction requirements without sacrificing accuracy. The resulting predicted values are refined by the use of diagrams in order to account for the local effects on fetch length, shoaling and refraction. On a long term basis (five years of use), the system which is independent of location, has proven itself to be the best for offshore operations in shallow water.
The Institute considers wave forecasting to be one of its primary products and is constantly analyzing, refining and updating its procedures to improve the product.
A most effective way of refining forecasting techniques is to perform a "post mortem" analysis of selected storms and compare the results to actual observations. This is done by wave hindcasting and forecast evaluation. It is not sufficient to merelyrecalculate our forecasts using observed data. A re-analysis of the basic system must be made to insure that, while results may be satisfied through statistical verification, physical laws governing the sea's response to particular atmospheric conditions are not violated.
Presented here, are the results of one such wave forecast evaluation study. The region of interest is the Grand Banks Area near Nova Scotia and Newfoundland particularly that area surrounding Sable Island.

Two Computing Methods
A method of computing significant wave heights has been developed to account for the proximity of the forecast point to a moving circular storm taking into account location, extent, intensity and movement.