Preliminary Performance Evaluation Research Articles

Analytical Simulation of the Passive Solar System

The computer simulation is a useful tool for heat transfer analysis of the passive solar systems especially in preliminary performance evaluation, implementation, and/or optimization of the system configurations in the course of the development and constructive design. The present article describes advantages and conditions of an application of the simulation scheme to the passive solar system analysis, along with design criterion and requirements for analytical heat transfer models for the passive solar system simulations. A state-of-the-art program, ESPAR, used for the simulations, has been developed for the elementary heat transfer analysis of the passive solar systems constructed as a part of a single room residential building, and formulated around a finite differential heat conductive model combined with typical passive solar system submodels. Analytical results by ESPAR for the direct gain system with sensible or latent heat storage wall and Trombe wall system are presented comparatively with measured results.

Performance modelling of a fault-tolerant real-time multiprocessor using stochastic Petri nets

The fault-tolerant multiprocessor (ftmp) is a bus-based multiprocessor architecture with real-time and fault- tolerance features and is used in critical aerospace applications. A preliminary performance evaluation is of crucial importance in the design of such systems. In this paper, we review stochastic Petri nets (spn) and developspn-based performance models forftmp. These performance models enable efficient computation of important performance measures such as processing power, bus contention, bus utilization, and waiting times.

A Microcomputer Interface for Digital Seismic Data Acquisition Systems

This paper describes two schemes for interfacing a microcomputer to a digital data acquisition system. The first scheme for data rates greater than 400 K baud utilizes a direct memory access. The other uses the interrupt system of a microprocessor and is good for configurations limited to a maximum of 24 channels at a 1 ms sampling rate. Since this system is easily upgradable in terms of memory, software and special purpose hardware, this opens the door for low-cost microcomputer field systems which can at the least do preliminary performance evaluation currently being done by transporting test tapes from various exploration regions in the country to a central computer centre at Dehra Dun.

First tests of the liquid-helium distribution line for the FSU linac

The liquid-helium distribution system for the FSU superconducting linear accelerator has been installed and a preliminary evaluation of the system performance has been made. A heat leak of about 30 W was anticipated for the entire system. With two of the five cryostats in place, we estimate an overhead heat leak for the piping system of about 37 W.

Computer assessment of hemodynamic severity of coronary artery stenosis from angiograms

A computer-assisted analysis of coronary obstructions from cineangiograms is presented, which includes both the geometric and hemodynamic evaluation of coronary stenosis severity. Single frame images are digitized into a 512×512×8 bit array after a cine-to-video conversion. Automatic edge tracking is performed using a combination of derivative and threshold methods. Vessel borders from two orthogonal views of the arterial segment are used to create a three-dimensional reconstruction of the stenosis, which serves as a basis for calculation of absolute and relative geometric dimensions, stenotic resistance and trans-stenotic pressure gradient for various given flow rates. A preliminary performance evaluation of this method was made by analysis of x-ray phantoms representing stenoses of known dimensions, which were filmed under quasi-clinical conditions. The results are discussed with respect to their accuracy and reproducibility.

Preliminary analysis of RISC architectures performance

Analysing architecture performance is a step of utmost importance and interest in the process of computer architecture design. The paper deals particularly with special architectures of the Reduced Instruction Set Computer Space (RISCS) in order to obtain a preliminary evaluation of RISC's architectures performance and the approach to an optimal instruction set for an effective High Level Language Computer (HLLC). The new modular microcomputer consisting of instruction groups modules called MODHEL that has already been proposed has facilitated the investigation of the performance of a set of computers allocated within the RISCS. A comparative study of the dynamic instruction mix of four benchmark programs is performed with respect to the VAX 11/780, RISCI (Berkeley) and five versions of MODHEL. Preliminary results indicate that there is a strong chance that RISC-type computers could be designed to function as efficient low-cost systems.

Naval Airship Program for Sizing and Performance (NAPSAP)

This paper describes the Naval Airship Program for Sizing And Performance (NAPSAP) developed by the U.S. Naval Air Development Center (NAoC) for preliminary design and performance evaluations of Lighter-Than-Air (LTA) vehicles. Program capabilities have been tailored to vehicle sizes and missions currently being investigated as a part of the joint U . S . Navy U . S . Coast Guard Maritime Patrol Airship Study and NADC studies of Anti Suharine Warfare (ASW) Mission Concepts. The program has been designed to operate on a minimum of input data (only five cards are necessary), but has the capability to evaluate the influence of over 40 key parameters. NAPSAP provides easy parametric analysis for several optional levels of detail. Once the design section of NAPSAP converges on a vehicle which meets the input requirements, this vehicle can then be evaluated against a specified mission profile with all key parameters monitored by mission time increments.

Preliminary Evaluation of GPS Performance for Low-Cost General Aviation

Preliminary results of a simulation effort to evaluate the requirements and feasibility of the global positioning system (GPS) as a civil air navigation system are presented. Evaluation is made of GPS requirements, from operational considerations, such as application to nonprecision approaches. The conceptual low-cost GPS receiver simulated here does not correct for the ionospheric or trophospheric delay, is sequential in nature, tracks only four satellites, and is not mechanized to make independent range rate measurements based on the Doppler shift of the GPS carrier frequency. The proposed GPS system has significantly different performance characteristics from the presently used VHF omnidirectional range (VOR) solidus distance-measuring equipment (DME) system. The GPS is a low signal level system and many have a relatively slow data rate due to the low-cost sequential receiver design. The results indicate that although the conceptual low-cost GPS receiver/ navigator is potentially more accurate than a VOR, the accuracy may degrade during aircraft turns and satellite shielding periods.

Wing Planforms for Large Military Transports

Transport aircraft, designed for long-range military missions with heavy payloads, lead to wings with high aspect ratios and very large spans. A wing-geometry/cruise-speed optimization study was made of a large cantilever-wing military transport airplane. Preliminary design and performance evaluations were also made of a strut-braced wing airplane. Initial results obtained with statistical weights indicated small performance advantages for the cantilever-wing design. Subsequent results obtained with weights derived from detailed analytical structural analyses reversed the initial conclusions. These results indicated that unusual alternative configuration concepts cannot be discarded, based on small differences predicted during conceptual design studies.

An automated microscope for cytologic research a preliminary evaluation.

A research-oriented system for automated microscopy is described from an operational point of view. The system consists of a microscope, a TV camera, an automatic cell finder and a servo-driven computer controlled stage. The system is interfaced to a NOVA 840 computer having 112,000 words of 16-bit core memory and extensive peripherals. It is capable of performing a wide variety of image processing tasks and is being used to study various aspects of automated microscopy, with applications in, but not limited to, cytology. Results of preliminary performance evaluations are given.

High-Speed Distance Relaying Using a Digital Computer II-Test Results

An experimental general-purpose process-control digital- computer system described in a companion paper (I-System Description) provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line. The stored program performs all of the relaying functions using the output of an analog-to- digital converter which reads the instantaneous value of the power- system currents and voltages. Model line tests described here form the basis for preliminary performance evaluation. An automatic oscillograph and diagnostic programs will allow a study of field performance.

High-Speed Distance Relaying Using a Digital Computer I - System Description

An experimental general-purpose process-control digital computer system provides high-speed phase-and ground-distance fault protection of one 230 kV transmission line. The stored program performs all of the relaying functions using the output of an analog-to- digital converter which reads the instantaneous value of the power- system currents and voltages. Model line tests described in a companion paper (II -Test Results) form the basis for preliminary performance evaluation. An automatic oscillograph and diagnostic programs will allow a study of field performance.

FOOD MARKETING —WHY THE DEARTH OF CONTROVERSY?

Evaluation of performance in food marketing requires an examination of governmental and judicial agencies as well as a thorough delving of industrial secrets. A preliminary evaluation of performance suggests failure due to insufficient feedback of information to allow for adequate system anointer and control. Publications based on powers of search, subpoena, and seizure also suggest a history of inadequate performance and the weakness or absence of control variables. Since no ideal market institutions are known, and since we have reason to believe market performance is less than perfect, any absence of economic debate and controversy would signets the profession was relinquishing the field of market policy formulation to an economically unsophisticated judiciary and the aroused, if uninformed, housewives.

Continuous Production of Tablet Granulations in a Fluidized Bed II: Operation and Performance of Equipment

Data collected from batch runs in a 1-ft. diameter fluidized bed granulator were employed in preliminary evaluation of process performance. Moisture content, granule screen analysis, and compressibility tests were used to evaluate the granulated product. Process variables such as powder and liquid feed rates, inlet air temperature, and nozzle location influenced the characteristics of the product. Losses from the unit were related to cyclone collector efficiency. Data obtained from replicate continuous runs under selected operating conditions illustrated the ability of the process to maintain product uniformity from run to run. Finished granulations from the continuous runs were evaluated on a rotary press. Tablets made from these granulations conformed to tablets made from identical ingredients granulated by conventional techniques. Data collected from batch runs in a 1-ft. diameter fluidized bed granulator were employed in preliminary evaluation of process performance. Moisture content, granule screen analysis, and compressibility tests were used to evaluate the granulated product. Process variables such as powder and liquid feed rates, inlet air temperature, and nozzle location influenced the characteristics of the product. Losses from the unit were related to cyclone collector efficiency. Data obtained from replicate continuous runs under selected operating conditions illustrated the ability of the process to maintain product uniformity from run to run. Finished granulations from the continuous runs were evaluated on a rotary press. Tablets made from these granulations conformed to tablets made from identical ingredients granulated by conventional techniques.