Programmable Test Research Articles

IVI comes of age: An overview of IVI specifications with current status

IVI stands for Interchangeable Virtual Instruments; the IVI Foundation was formed in 1997 and is a consortium founded to promote standard specifications for programmable test instruments. The foundation focuses on the needs of users who build high performance test systems. By building on existing industry standards, such as VXIplug&play driver concepts, the Foundation's goal is to deliver specifications that simplify interchangeability, provide better performance, and maintainable test programs. To date, only a few IVI drivers have been available. In the past year, the IVI Foundation finished a major revision of it's architecture and has released a blizzard of specifications, increasing its IVI Class specification by 80% and dramatically improving the consistency and quality of released drivers. The DoD has expressed major interest in IVI's success. With the recent successful completion of the current set of specifications, DoD is interested in becoming involved in defining the next set of Class Specifications. The NxTest Working Group lists IVI as a key technical element, and DoD has recently requested that the IVI Foundation consider Electro Optical equipment for their next set of Class Specifications; a Working Group has been formed to more clearly define this activity.

Biomechanical Testing of an Artificial Cervical Joint and an Anterior Cervical Plate

An in vitro biomechanical study was conducted to determine the effects of fusion and nonfusion anterior cervical instrumentation on cervical spine biomechanics in a multilevel human cadaveric model. Three spine conditions were studied: harvested, single-level artificial cervical joint, and single-level graft with anterior cervical plate. A programmable testing apparatus was used that replicated physiologic flexion/extension and lateral bending. Measurements included vertebral motion, applied load, and bending moments. Relative rotations at the superior, implanted, and inferior motion segment units (MSUs) were normalized with respect to the overall rotation of those three MSUs and compared using a one-way analysis of variance (P < 0.05). Application of an anterior cervical plate decreased motion across the fusion site relative to the harvested and artificial joint spine conditions. The reduced motion was compensated for by an increase in motion at the adjacent segments. Use of an artificial cervical joint did not alter the motion patterns at either the instrumented level or the adjacent segments compared with the harvested condition for all modes of testing.

Aerodynamic Design and Experimental Investigation of the Sailplane Wing Tip Devices

This paper describes an experimental set-up for the investigation of wing tip devices developed as part of a study into the velocity and vorticity distributions in the flow field behind winglets, using hot-wire anemometry. In this study, effort was focused on gaining a greater understanding of what happens in the region where the winglet joins the wing. The measurements were performed in the Handley-Page wind tunnel of the Department of Aerospace Engineering at the University of Glasgow. In order to carry out measurements with the hot-wire anemometry system, a new traverse mechanism was designed and manufactured. This traverse mechanism was integrated with the other test instrumentation to create a complete measurement chain. The complete system allows fully automated hot wire measurements to be made over a defined area using programmable test parameters.

In vitro comparison of a translational anterior cervical plate with a constrained anterior cervical plate

In vitro comparison of a translational anterior cervical plate with a constrained anterior cervical plate

Anterior cervical plating reverses load transfer through multilevel strut-grafts.

In vitro biomechanical study using a programmable testing apparatus that replicated physiologic flexion/extension cervical spine motion and loading mechanics. To determine the influence of anterior plating on multilevel cervical strut-graft mechanics in vitro. The addition of anterior instrumentation does not prevent construct failure in multilevel cervical corpectomy. Six fresh human cadaveric cervical spines (C2-T1) were tested in the four following sequential conditions: harvested, C4-C6 corpectomy, strut-grafted, and strut-grafted with an anterior cervical plate. A force-sensing strut-graft was used to measure compression/tension, flexion/extension and lateral bending moments, and axial torsion. Parameters of stiffness, vertebral motion, and strut-graft loads were compared to determine differences between the four spine conditions. Application of the anterior plate significantly increased the global stiffness (P < 0.01) and decreased the local motion (P < or = 0.01) of the instrumented levels (C3-C7). Flexion of the strut-grafted spine loaded the strut-graft, whereas extension unloaded the strut-graft. With the anterior plate, flexion of the plated spine unloaded the strut-graft. Extension significantly loaded the strut-graft more than similar degrees of flexion in the strut-grafted condition (P = 0.01). Strut-graft loading end limits of 225 N were reached with a mean 7.5 degrees extension in the plated spines. Anterior multilevel cervical plating effectively increases stiffness and decreases local cervical motion after corpectomy. However, anterior cervical plating also reverses graft loads and excessively loads the graft in extension, which may promote pistoning and failure of multilevel constructs.

The in vitro effects of instrumentation on multilevel cervical strut-graft mechanics.

Biomechanical study using a programmable testing apparatus that replicated physiologic flexion-extension cervical spine motion, and loading mechanics. To determine the influence of anterior, posterior, or combined plating on multilevel cervical strut-graft mechanics in vitro. The addition of instrumentation does not prevent construct failure in multilevel (more than two levels) cervical corpectomy. Six fresh human cadaveric cervical spines (C2-T1) were tested in six sequential conditions that included harvested (H), C4-6 corpectomy, strut grafted, strut grafted with an anterior cervical plate (SGAP), strut grafted with posterior plates (SGPP), and strut grafted with combined anterior and posterior plates (SGAPP). A customized force-sensing strut graft (FSSG) was used to measure axial compression-tension, flexion-extension and lateral bending moments, and axial torsion. Parameters of stiffness, segmental vertebral motion, and strut-graft loads were compared, to determine differences among the spine conditions. Flexion of the strut-grafted spine loaded the FSSG, and extension motion unloaded the FSSG. With the anterior plate, flexion of the SGAP spine significantly unloaded the FSSG; extension loaded the FSSG more than flexion of the unplated spine (P = 0.03). The opposite occurred with the posterior plates (SGPP), where flexion of the spine significantly loaded the FSSG (more than the strut grafted spine) and extension unloaded the FSSG (P < 0.03). The combined construct (SGAPP) counteracted the tension band effect of the individual plates and demonstrated significantly less overall FSSG load change than either plate alone (P = 0.03). Multilevel cervical instrumentation effectively increases stiffness after corpectomy. However, anterior or posterior plating alone excessively loads the graft with small degrees of motion, which may promote pistoning and failure of multilevel constructs.

Hypersequential programming: a new way to develop concurrent programs

The authors present hypersequential programming, a new method that eases the difficulty of concurrent programming and makes the concurrent program highly reliable. The difficulty of concurrent programming is due mainly to its nondeterminism. The authors classify nondeterminism into three types: intended, harmful, and persistent. In traditional concurrent programming, a programmer first designs and implements programs so as to maximize concurrency, which may include all three types of nondeterminism. She then tries to detect harmful nondeterministic behavior by testing and debugging them. However, removing all harmful nondeterministic behavior is actually very difficult. Hypersequential programming, on the other hand, first serializes the concurrent program to remove all types of nondeterminism, and then the programmer tests and debugs it as a sequential program. Finally, it is parallelized by restoring only intended and persistent nondeterminism. Hypersequential programming can develop a highly reliable concurrent program, because the injection of harmful nondeterminism is precluded. In this article, the authors also present a simple embodiment of hypersequential programming using Petri nets.

Automatic inductive voltage divider bridge for operation from 10 Hz to 100 kHz

A bridge to calibrate programmable and manual inductive voltage dividers is described. The bridge is based on a programmable 30-b binary inductive voltage divider with terminal linearity of +or-0.1 ppm in phase and +or-2 ppm quadrature at 400 Hz. Measurements of programmable test dividers can be automated using software developed to align the bridge components and perform an automatic balance. >

Development of a Control System for a Film Processing Device and Technology Transfer to an Industrial Company

In cooperation with a small industrial company, the Institute designed a microcomputer based control unit for the automation of a film processing device. Special emphasis was laid on the detailed description of the concept and the operator interface. The concept supports all developing processes known and is extendible. The process steps are described by functional diagrams which aid an easy programming by students. A programmable testing device is utilized to inspect the product automatically. Due to the strict definition of both partners' tasks the cooperation between partners from distinct disciplines was accomplished successfully.

Automated Testing of Low-Orbiting Satellites

This paper describes the hardware, software, and test procedures implemented at a ground station for the automated testing of a polar-orbiting satellite in a low orbit. The satellite passes during the testing were characterized by short visibility times of no more than 18 muin and by high rates of change of the link parameters as seen by the ground station. The advantages of automated testing became apparent for these dynamic conditions. Under computer control throughout the pass, programmable test instruments were commanded and data was collected and stored. Data reduction was performed after the pass.

PART: Programmable Array Testing Based on a Partitioning Algorithm

PART is a system for PLA testing and design verification, intended to be properly interfaced with other existing tools to generate a comprehensive design environment. To this purpose, it provides several facilities, among which the capability of generating a fault population on the basis of layout information. PART aims at producing a very compact test set for all detectable crosspoint defects, using limited amounts of run time and storage. This is achieved by means of an efficient partitioning algorithm together with powerful heuristics. Test minimality is ensured by a simple procedure. In the present paper these are discussed, experimental results are given and a comparison with competing strategies is made.

Some progress toward a quantitative description of human neuromuscular dynamics

s $71 SOME PROGRESS TOWARD A QUANTITATIVE DESCRIPTION OF HUMAN NEUROMUSCULAR DYNAMICS GEORGE I. ZAHALAK (Department of Mechanical Engineering, Washington University, St. LOUIS. MO 63130, U.S.A.) The quantitative description of the dynamic behavior of human skeletal muscle as it functions normally in-t-it-o is a very difficult problem for which only limited results have been obtained to date. Some progress has been made recently by the author and his associates via extensive frequency-response tests of the forearm flexion/extension system in normal adult males. These experiments invrolved both voluntary and externally forced oscillations. but were restricted to smnfl fractional variations in muscle length, and suggested mathematical models for bo!h (1) the dynamic relation between force, length and EMG in muscle, and (2) the dynamic relation between reflex EMG and muscle stretch. A new versatile testing device, dubbed the Programmable Limb Testing System (PLTS). has made possible the extension of these experiments to large variations in muscle length and wider dynamic ranges: experiments are currently in progress to verify and generalize the small-amplitude frequency-response results. A new approach to formulating a whole muscle model valid for large variations in muscle length, both in shortening and in stretch, has been proposed by the author. This model, termed the Distribution-Moment Model, is based directly on current biophysical theories of molecular contraction dynamics and appears o olfer several advantages over the classic A. V. Hill model while retaining much of the latter’s simplicity. EFFECT OF IMMOBILIZATlON AND REMOBILIZATION ON THE PROPERTIES OF THE MEDIAL COLLATERAL LIGAMENTS SAVIO L-Y. WOO, PETER 0. NEWTON and MARK A. GOMEZ (San Diego Veterans Administration Medical Center and University of California, San Diego, La Jolla, CA 92093, U.S.A.) Twenty-two New Zealand white rabbits were divided into four groups: (1) 9 weeks of immobilization, (2) 12 weeks of immobilization, (3) 9 weeks immobilization + 9 weeks remobilization and (4) 12 weeks immobilization + 9 weeks remobilization. At sacrifice, the medial collateral ligament (MCL) specimen including the bones were tested following Woo et al. The load-deformation curve for the MCL-bone complex and the load-strain curve of the MCL substance were obtained. With immobilization, the strength characteristics of the MCL-bone complex reduced to approximately l/3 that of the controls. There were Iarge differences in the load-strain curves between the control and experimental MCL’s indicating that changes in the ligament mechanical properties had possibly occurred. Interestingly, the load-strain curves of the experimental and control MCL from the remobilization groups were similar, indicating recovery of the properties of the MC substance. The structural strength of the MCL-bone complexes from the experimental knees, however, continued to be inferior (Noyes er 01.. 1974).

A Precision Instrument for the Clinical Measurement of Stereoscopic Acuity

When tested by different methods, a patient's stereoscopic acuity is sel­dom the same. This raises the ques­tion as to which one gives the true stereoscopic acuity. To answer this, a programmable test for stereoscopic acuity was designed to serve as a test­ing standard. This is described and a comparative study with it and four other tests is reported.

Digital simulation of fault autoreclosure sequences. With particular reference to the performance evaluation of protection for EHV transmission lines

The successful development of EHV transmission-line protection increasingly depends on a detailed simulation of power-system faulted responses. In consequence, increasing use is being made of programmable test equipment in which the primary-system responses are simulated digitally. Previous work on digitally simulating faulted-system responses has been concentrated very largely on the initial faulted period prior to the initiation of an autoreclosure sequence. The implications of incorrect operation of protection at any time throughout the process of fault clearance are, however, often serious, and the paper is therefore concerned with detailing methods of frequency-domain simulation which have been developed to greatly extend the capability of computer-based simulation methods in their application to protective-gear testing. Problems associated with the simulation of various network time nonlinearities are overcome, and the new methods enable both 3-phase and single-pole autoreclosure to be simulated. The paper concludes with a presentation of some simulation studies relating to a short 500kV interconnection which is subjected to various transient and sustained fault conditions

Discussion on “Programmable testing equipment for power-system protective equipment”

Discussion on “Programmable testing equipment for power-system protective equipment”

A Programmable Fault Testing Equipment for Combinational Networks

This paper deals with the design and construction of a fault-testing equipment. It can be used to test any type of permanent faults of stuck-at-type, whether single or multiple, in any irredundant combinational logic circuit with loop free interconnections. The inherent programming feature enables the system to test any arbitrary combinational network of any number of input variables with a maximum of eight and with an internal structure, made up with any arbitrary type of logic blocks. The presence or absence of any fault in the network under test is readily detected.

Programmable testing equipment for power-system protective equipment

Present testing equipment does not enable the performance of protective equipment to be assessed over the wide range of conditions encountered on modern power systems. System behaviour may be determined by digital-computer studies or measurements made either on transient analysers or the actual networks. Thereafter it is desirable that the appropriate voltages and currents be regenerated in laboratories for use during the development of new protective equipment, or when assessing the suitability of established schemes for particular applications. The authors have developed equipment into which details of any desired aperiodic testing waveform can be fed, either in digital form on punched paper tapes, or in analogue form on magnetic tapes. Although the signals so derived may be amplified and fed to any voltage circuits associated with protective schemes, the apparent power demands made by current circuits under fault conditions may be so great, if current transformers are included, that the necessary amplifiers would be too large to be practical. An arrangement has been developed in which the correct currents are produced for feeding to the relay current circuits by including small model transformers that simulate the effects of the actual current transformers and enable the necessary allowances to be made. In this way the required power handling capability of each amplifier is much reduced. Details are given of the complete prototype equipment which has been produced, and test results are provided to illustrate its effectiveness.

The failure of rock beams: Part II—Experimental studies

Complete force-displacement curves characterizing the collapse process of plexiglas and rock beams were experimentally obtained in a closed-loop programmable testing system with an appropriate choice of feedback signal. A comparison was made of the experimental observations and theoretical predictions (based on the method outlined in Part I) for the specific testing situation. The basic validity of the theoretical method was established from the shape of the curves, the displacement values, local beam-unloading moduli values and crack-length measurements.

A Computer-Controlled RF Test System

A programmable computer-con trolled RF Test system capable of testing deliverable radio equipment was developed and is now operating in the Manufacturing activity of Government and Commercial Systems, RCA Corporation. The system is capable of automatically testing receivers, transmitters, sub-assemblies and components in the HF, VHF, and UHF frequency bands and is controlled with an RCA 1600 Computer. Programming is performed by Manufacturing Test Engineers using a high order test language. This paper describes the technical characteristics of this system.