Environmental Test System Research Articles

Research on Redress System of Vibration Table in Multi-Parameter Combined Environment Test System

The coupling between vibration and centrifugal field is quite strong in multi-parameter combined environment test system. The motion part of vibration table deviates from its original operation position by the action of centrifugal force, which ends in the stuck of armature and causes damage to vibration table. In order to solve such problem, an air-push-type armature redress system with displacement feedback was proposed, which provided a recovering force to counteract the centrifugal force and pushed the motion component to its designed operation position. Some improvements were also made to enhance its reliability. The result of simulation and test about the armature redress system demonstrates that the system has an excellent performance and meets the requirement of counteracting the centrifugal force, which guarantees that the vibration table could work in centrifugal field and multi-parameter combined environment.

A Design and Implementation of P2P Network Traffic Identification System

The P2P streaming media technology is popular and promising in recent years, to ensure the correctness of the identification method, and improve the identification rate and accuracy of the network traffic, this paper proposes a identification principle and algorithm of the P2P network traffic, and gives the overall structure of the system, Finally, puts up the system test environment. The experimental results show that the identification method of the network traffic proposed in this paper can effectively improve the identification rate and accuracy of the network traffic, the scheme has the value of further research and promotion.

Research on Environmental Durability Testing System for Automobile Engine ECU

Based on the principle and specifications of Environmental Durability Test on automobile engine ECU, an open, intelligent and practical ECU durability testing system (EDTS) is designed. The system consisted of a simulation platform and a testing management software. The platform provided stimulating sensor signals and simulation loads, and an online automotive environment was built. The management software sent various instructions to set up the platform and read the ECU running status data. And this EDTS has been applied to test a kind of domestic automobile engine ECU．The experimental results shows that the mean time to failure (MTTF) of ECU samples was improved and the testing period was shortened greatly.

통합 시스템을 위한 출력 분포 기반 적응적 랜덤 테스팅

Adaptive Random Testing (ART) aims to enhance the performance of pure random testing by detecting failure region in a software. The ART algorithm generates effective test cases which requires less number of test cases than that of pure random testing. However, all ART algorithms currently proposed are designed for the tests of monolithic system or unit level. In case of integrated system tests, ART approaches do not achieve same performances as those of ARTs applied to the unit or monolithic system. In this paper, we propose an extended ART algorithm which can be applied to the integrated system testing environment without degradation of performance. The proposed approach investigates an input distribution of the unit under a test with limited number of seed input data and generates information to be used to resizing input domain partitions. The simulation results show that our approach in an integration environment could achieve similar level of performance as an ART is applied to a unit testing. Results also show resilient effectiveness for various failure rates.

Using QSPS in Developing and Realization of a Production Line in Automotive Industry

<p>Using the QSPS (Quality System for the production software) for industrial projects and not only therefore, has led to accurate running of the production line from beginning of the SOP (Start of Production). This paper presents the application way of the QSPS at one of the strongest European automotive company. By using of this system several significant costs savings and quality improvement can be observed.<br /> The content of this paper will show step by step how to use QSPS for the integration of a production line in the traceability system from a big company in automotive industry.<br /> The production line involved contains 56 production equipments, which have to be passed trough by the product before being packet and deliver to the customer.<br /> The control of the line is done by this traceability system, so the impact of this system with the quality of the product is very high. The structure of this system contains 7 steps. All of these steps are followed and executed in each System (test, pilot and production environment).</p>

Hardware-in-the-Loop System for Testing Automotive Ecu Diagnostic Software

The purpose of this paper is to present an approach to testing ECU diagnostic software using hardware-in-the-loop (HIL) systems at Jaguar Land Rover (JLR). The increasing complexity of embedded software for automotive electronic control units (ECUs) requires a convenient and flexible environment for system testing. On-board diagnostic software represents a significant proportion of ECU software and consequently, the effort, in terms of time and manpower required to determine the validity of ECU software is becoming excessive. The process for validating on-board diagnostic software is traditionally achieved using tests carried out with actual vehicles. Some tests are difficult and expensive to perform in vehicles. Automated testing offers an approach that can improve the validation process whilst providing the potential for cost saves. Since JLR utilises ECUs from different suppliers, the development of a generic approach to automated testing is vital.

Efficient development of a web‐based environmental testing system using a novel two‐layer software architecture

AbstractThis work proposes a two‐layer software architecture and design considerations for the efficient development of a Web‐based environmental testing system. The efficiency of developing such a system can be significantly improved since the upper layer, called the Web application, can immediately employ the uniform interface and follow the call flow provided in the lower layer, called the COM component. The COM component particularly addresses the integration of various instrument control mechanisms and the concurrency issue, while the Web application addresses database, security, modularity, and graphic user interface (GUI) issues. Moreover, based on the proposed software architecture and design considerations, a Web‐based environmental testing system, called the Web‐based Automatic Measurement System (Web AMS), is developed to validate the efficiency of this architecture and address the above issues. The proposed synchronization mechanism, not only enables many experiments to share one Digital Multi‐Meter (DMM) simultaneously, but also allows many remote clients to monitor the status of operating devices in a progressing experiment concurrently. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 412–421, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20238

The design and implementation of a simulated trackside environment test system for an electric point machine

The background and constraints involved in condition monitoring of railway point operation are reviewed and discussed. An approximate method to replicate maladjustment, based on industry experience, is proposed and a computer simulation of the point machine and load is introduced. In view of uncertainty in results, a mechanical solution was preferred and the design and implementation of a simulated trackside environment test system and the instrumentation and measurement techniques used to gather practical data are described. In view of the severe railway environment, only electrical quantities were monitored using non-invasive sensors. A comparison is made with site data. Conclusions include the estimated payback available from implementing the condition monitoring system.

Environmental Performance Testing System for Thermostructure Materials Applied in Aeroengines

The conventional ultimate performance test by applying a component in its true application (i.e., in an engine) is often very expensive and impractical when dealing with developmental materials. Simpler, less expensive, and more practical test methods must be utilized. The present work aims toward the applications of an innovative methodology for testing environmental performance of advanced Ceramic Matrix Composites (CMCs) in the presence of combined mechanical, thermal, and environmental applied conditions. To obtain a comprehensive understanding of how a composite might perform in certain application environments, a newly developed environmental performance testing system, which is able to provide the fundamental damage information of the composites in simulating service environments including variables such as temperature, mechanical and thermal stresses, flowing oxidizing gases and high gas pressure, is proposed. The system comprises of two subsystems: (1) equivalent experimental simulating subsystem, and (2) wind tunnel experimental simulating subsystem. The evolution mechanisms of the composites properties and microstructures can be achieved by the former, and then be validated and modified by the latter. Various loading (e.g. fatigue, creep), various atmospheres (e.g. argon, oxygen, water vapor, wet oxygen and molten salt vapor) and various temperature conditions (e.g. constant or cyclic temperatures) can be conducted on the system. Some typical experimental results are presented in this paper. Large quantities of tests have demonstrated the extraordinary stability and reliability of the system.

Calibrating software reliability models when the test environment does not match the user environment

AbstractSoftware failures have become the major factor that brings the system down or causes a degradation in the quality of service. For many applications, estimating the software failure rate from a user's perspective helps the development team evaluate the reliability of the software and determine the release time properly. Traditionally, software reliability growth models are applied to system test data with the hope of estimating the software failure rate in the field. Given the aggressive nature by which the software is exercised during system test, as well as unavoidable differences between the test environment and the field environment, the resulting estimate of the failure rate will not typically reflect the user‐perceived failure rate in the field.The goal of this work is to quantify the mismatch between the system test environment and the field environment. A calibration factor is proposed to map the failure rate estimated from the system test data to the failure rate that will be observed in the field. Non‐homogeneous Poisson process models are utilized to estimate the software failure rate in both the system test phase and the field.For projects that have only system test data, use of the calibration factor provides an estimate of the field failure rate that would otherwise be unavailable. For projects that have both system test data and previous field data, the calibration factor can be explicitly evaluated and used to estimate the field failure rate of future releases as their system test data becomes available. Copyright © 2002 John Wiley & Sons, Ltd.

Hardware-in-the-loop environment for servo system controller design, tuning and testing

The paper analyses the possibility to replace the hydraulic and mechanical parts of a hydraulic position servo with a real-time simulation model. The aim is to test the controller hardware against the simulation model that includes the dynamics of the servo system as well as the feedback sensors and amplifier card. The requirements caused by this hardware-in-the-loop (HIL) approach are analyzed. A special attention is paid to the correct modeling of incremental encoders that are widely used as a feedback sensor. Experimental results show that there is no remarkable difference between the responses of the real system and HIL model and so the HIL model can replace the real system.

Degradation of a mixture of high‐molecular‐weight polycyclic aromatic hydrocarbons by aMycobacteriumstrain PYR‐1

Abstract Mycobacterium sp. PYR‐1, which was previously shown to mineralize several individual polycyclic aromatic hydrocarbons (PAHs), simultaneously degraded phenanthrene, anthracene, fluoranthene, pyrene and benzo[a]pyrene in a six‐component synthetic mixture. Chrysene was not degraded significantly. When provided with a complex carbon source, Mycobacterium sp. PYR‐1 degraded greater than 74% of the total PAH mixture during 6 d of incubation. Mycobacterium sp. PYR‐1 appeared to preferentially degrade phenanthrene. No significant difference in degradation rates was observed between fluoranthene and pyrene. Anthracene degradation was slightly delayed but, once initiated, proceeded at a constant rate. Benzo[a]pyrene was degraded slowly. Degradation of a crude mixture of benzene‐soluble PAHs from contaminated sediments resulted in a 47% reduction of the material in 6 d compared with that of autoclaved controls. Experiments using an environmental microcosm test system indicated that mineralization rates of i...

Load testing software using deterministic state testing

In this paper we introduce a new load testing technique called Deterministic Markov State Testing and report on its application. Our approach is called “deterministic” because the sequence of test case execution is set at planning time, and “state testing” because each test case certifies a unique software state. There are four main advantages of Deterministic Markov State Testing for system testers: provision of precise software state information for root cause analysis in load test, accommodation for limitations of the system test lab configuration, higher acceleration ratios in system test, and simple management of distributed execution of test cases. System testers using the proposed method have great flexibility in dealing with common system test problems: limited access to the system test environment, unstable software, or changing operational conditions. Because each test case verifies correct execution on a path from the idle state to the software state under test, our method does not require the continuous execution of all test cases. Deterministic Markov State Testing is operational-profile-based, and allows for measurement of software reliability robustness when the operational profile changes.

A computer‐controlled environmental test system for high pin‐count integrated circuit packages

AbstractAn automated environmental stress testing system, designed and assembled for testing of high pin‐count integrated circuit packages and surface mount solder joint reliability is described. Details are given of the software and hardware used in the control of the environment chambers used, in monitoring of test specimen reliability parameters and in control and monitoring of special purpose integrated circuits for testing of IC package reliability. In addition, an automatic system for monitoring of the resistance of fine pitch surface mount solder joints and for detection and recording of thermally induced intermittent open circuits in these joints is described.

A case study in test environment evolution

As the demand for increasingly complex software systems grows, and our software development environments become increasingly sophisticated in response, our testing technology must keep pace. This paper describes the evolution of one software testing environment and the genesis of its logical successor. pastel (PICS Automated System Testing Environment for Leap) originated over a decade ago, with an interpreter for a simple testing language used on a single project by a group of about ten people. As the demands of testing very large systems grew, pastel 's functionality expanded. Today's pastel includes facilities for creating a test by simply exercising the system under test, for running the test in a variety of modes, and for capturing and automatically analyzing test results. pastel allows application experts to create tests easily; no sophisticated programming skill is required. pastel is now used by projects throughout the Software Technology and Systems Area of Bell Communications Research. pastel is a relatively mature product, an adequate testing system for the monolithic database systems it was intended to exercise. astra , its successor, is now being designed to test systems of interacting systems built on different sizes and flavors of hardware. This paper reviews the evolution of pastel and the preliminary design work and unifying concepts underlying astra .

Performance evaluation through job scheduler modeling

The scheduler in the Cyber-176 computer does the major functions of routing the job through the system, controlling job's progress through aging and swapping of jobs between various queues and resource allocation among jobs. This paper reports some results of the performance evaluation study of the Cyber-176 by modeling the scheduler as the heart of the system. The study explores the effects of varying the scheduler parameters in the performance of the machine in a particular installation. The basic theme of the paper is that the selection of parameters in a laboratory or a system test environment may not always result in the best performance in an actual installation. The simulation provides vital information for installation management and tuning the operating system.

Research and Testing

Equipment, Programmes, Techniques and Projects. STRESS CORROSION TESTING MACHINE Saml. Denison & Son Ltd., Moor Road, Leeds 10, are now manufacturing a new environmental testing system — the T66 stress corrosion machine based on an original design licensed from British Aircraft Corporation (Operating) Ltd. of London. This machine is a four channel, vertical machine capable of testing 12 specimens simultaneously under load up to 10 tons (20,000 lb.). The specimens may be round or flat, three per channel, all loaded through special stainless steel holders and shackles. These shackles take over the specimen load when a specimen breaks, so maintaining load on the other specimens in the channel. Load is applied hydraulically and indicated on two facia dials. The hydraulic pressure is derived from an air/hydropump actuated by pressurised nitrogen. During a test the load on the specimens remains constant to plus or minus 100 lb. The environmental chamber consists of a polythene sleeve held in position by rubber O‐rings clamping on to Perspex top and bottom flanges thus making an airtight enclosure; into this can be fed the corrosive atmosphere. A salt‐spray unit is fitted in the centre for supplying one or all chambers. When sulphur dioxide is used, the supply from a cylinder is mixed with clean air and fed in via a flowmeter at 0.01–3 per cent mix.

Concepts and practices in the assessment of human performance in Air Force systems. AMRL-TR-65-168.

Abstract : The report describes the current practices and evaluative aspects of human performance assessment in Air Force Systems. The human performance test programs for thirty-four systems and subsystems representing the major types of systems (aeronautical, electronic, missile, and space) used by the Air Force are reviewed. For these systems, the major functional areas covered include: (1) air Force policies, directives, requirements, and constraints concerning the development and assessment of system tests and human performance; (2) the behavioral sciences approach to, and technology for, assessing human performance; and (3) Air Force practices in assessment of human performance. Throughout, the systems context, within which human performance is conceived and evaluated, is emphasized. Consequently, the techniques within the behavioral sciences for examining human performance conceptually and empirically in the system test environment is a particularly practicable part of the report. The report is supported by many tables and charts, excerpts from test directives pertinent to human performance assessment, and approximately 600 categorized references.