Optimization Model for Environmental Stress Screening of Electronic Components

Environmental stress screening (ESS) is a technological process to reduce the costly early field failure of electronic components. This paper builds an optimization model for ESS of electronic components to obtain the optimal ESS duration. The failure phenomena of ESS are modeled by mixed distribution, and optimal ESS duration is defined by maximizing life-cycle cost savings under the condition of meeting reliability requirement.

Problems of Environmental Acceptance Tests on Power Transmission and Transformation Projects

Based on the experience of environmental acceptance tests for power transmission projects, the problems found in acceptance tests and the system shortcomings of acceptance test itself are analyzed. Recommendations are provided to improve the future work.

Stereoscopic Camera-Sensor Model for the Development of Highly Automated Driving Functions within a Virtual Test Environment

The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.

5G technology requirements and related test environments for evaluation

To meet the considerably increase of mobile data traffic and wireless communication connections around 2020,the 5th generation(5G)mobile network will necessarily consider more frequency bands,enabling technologies and diversified key performance indicators and test environments comparing with existing network,for example Long Term Evolution.More specifically,the obvious difference between 5G and previous wireless communication system are not only included eMBB(enhance mobile broadband) usage scenario,but also introduced mMTC(massive machine type communications)and URLLC(ultra-reliable and low latency communications) usage scenarios.Hence,in order to evaluate 5G related technologies,some novel test environments will be widely discussed,as well as,certain new key performance indicators will be drawn into5 G evaluation methodology for satisfied new requirements.We will discuss characteristic of these 4 candidate test environments,such as indoor isolated environment,high speed train environment;and the definition of 15 keys performance indicator will be explained and clarified,for example,Throughput,Network Energy Efficiency,Device Connection Density and so on.Furthermore,high-level assessment method of each test environment also will be initially considered.It is notable that an initial evaluation of indoor isolated environment also can be found,which the results show that there are 3 times average cell spectral efficiency than IMT-advanced's in same test environment.

Experimental Study on Purification Efficiency of Air Purifier for the Indoor Total Volatile Organic Compounds

By using total volatile organic compounds （TVOC） as the objective volatile pollutant, the purification efficiency of some representative air purifiers bought in the market was determined under the relatively independent and stable environmental conditions supplied by the self-made multi- functional environmental test chamber. Various evaluation parameters of TVOC were calculated based on the tested results, such as purification ef- ficiency and removal rate. The results showed that the TVOC purification efficiency increased with enhancing the temperature or lessening the rela- tive humidity, but this effect is not obvious. The air purifiers which use photocatalytic technology have higher TVOC purification efficiency than those which only use some adsorption technology. The purification efficiency and removal rate can be more accurate to evaluate the purification efficiency of air purifiers.

T-Ring无线电综合测试场的构建(英文)

Outfield testing is an effective measure to check the performance of wireless networks and facilities.Current outfield testing environment has inherent fluctuation due to the wireless propagation condition and has other disadvantages such as nonsupport for multiple scenarios,and low-level yet high-cost auto-control capability.In this paper,the conception of a radio testing environment,known as T-Ring(Integrated-Testing Ring),is proposed.It is based on a novel fitting degree evaluation frame.The testing ring can achieve high level of fitting degree to the real network so that the fluctuation of the wireless environment will be under control or even eliminated.This paper will choose some typical performance indicators and obtain corresponding statistical data in both the real network and system level simulation.A complete set of procedures is also given in this paper to evaluate the fitting degree of testing results and simulation results.It proves that the simulation highly fits to the real network and the simulation configuration can be used to construct the testing ring.At the same time,the advanced radio testing ring integrates multiple radio access technologies,scenarios and facilities from different manufacturers.It can improve the efficiency of wireless outfield testing and lower the cost of operators and manufacturers.

An intelligent control method for a large multi-parameter environmental simulation cabin

The structure and characteristics of a large multi-parameter environmental simulation cabin are introduced.Due to the diffculties of control methods and the easily damaged characteristics,control systems for the large multi-parameter environmental simulation cabin are diffcult to be controlled quickly and accurately with a classical PID algorithm.Considering the dynamic state characteristics of the environmental simulation test chamber,a lumped parameter model of the control system is established to accurately control the multiple parameters of the environmental chamber and a fuzzy control algorithm combined with expert-PID decision is introduced into the temperature,pressure,and rotation speed control systems.Both simulations and experimental results have shown that compared with classical PID control,this fuzzy-expert control method can decrease overshoot as well as enhance the capacity of anti-dynamic disturbance with robustness.It can also resolve the contradiction between rapidity and small overshoot,and is suitable for application in a large multi-parameter environmental simulation cabin control system.

Model-based robustness testing for avionics-embedded software

Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness testing for embedded software systems. It is a system-level black-box testing approach in which the fault behaviors of embedded software is triggered with the aid of modelbased fault injection by the support of an executable model-driven hardware-in-loop （HIL） testing environment. The prototype implementation of the robustness testing environment based on the proposed approach is experimentally discussed and illustrated by industrial case studies based on several avionics-embedded software systems. The results show that our proposed and implemented robustness testing method and environment are effective to find more bugs, and reduce burdens of testing engineers to enhance efficiency of testing tasks, especially for testing complex embedded systems.

Environmental test of the BGO calorimeter for DArk Matter Particle Explorer

DArk Matter Particle Explorer （DAMPE） is the first Chinese astronomical satellite, successfully launched on Dec. 17 2015. As the most important payload of DAMPE, the BGO calorimeter contains 308 bismuth germanate crystals, with 616 photomultiplier tubes, one coupled to each end of every crystal. Environmental tests have been carried out to explore the environmental adaptability of the flight model of the BGO calorimeter. In this work we report the results of the vibration tests. During the vibration tests, no visible damage occurred in the mechanical assembly. After random or sinusoidal vibrations, the change of the first order natural frequency of BGO calorimeter during the modal surveys is less than 5%. The shift ratio of Most Probable Value of MIPs changes in cosmic-ray tests axe shown, the mean value of which is about -4%. The comparison of results of cosmic-ray tests before and after the vibration shows no significant change in the performance of the BGO calorimeter. All these results suggest that the calorimeter and its structure have passed through the environment tests successfully.

Matrix Power Control Algorithm for Multi-input Multi-output Random Vibration Test

Both auto-power spectrum and cross-power spectrum need to be controlled in multi-input multi-output （MIMO） random vibration test. During the control process with the difference control algorithm （DCA）, a lower triangular matrix is derived from Cholesky decomposition of a reference spectrum matrix. The diagonal elements of the lower triangular matrix （DELTM） may become negative. These negative values have no meaning in physical significance and can cause divergence of auto-power spectrum control. A proportional root mean square control algorithm （PRMSCA） provides another method to avoid the divergence caused by negative values of DELTM, but PRMSCA cannot control the cross-power spectrum. A new control algorithm named matrix power control algorithm （MPCA） is proposed in the paper. MPCA can guarantee that DELTM is always positive in the auto-power spectrum control. MPCA can also control the cross-power spectrum. After these three control algorithms are analyzed, three-input three-output random vibration control tests are implemented on a three-axis vibration shaker. The results show the validity of the proposed MPCA.

Achieving superlubricity in DLC films by controlling bulk, surface, and tribochemistry

Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction[1].From a practical application point of view,this will be the most ideal tribological situation for many moving mechanical systems mainly because friction consumes large amounts of energy and causes greenhouse gas emissions[2].Superlubric sliding can also improve performance and durability of these systems.In this paper,we attempt to provide an overview of how controlled or targeted bulk,surface,or tribochemistry can lead to superlubricity in diamond-like carbon(DLC)films.Specifically,we show that how providing hydrogen into bulk and near surface regions as well as to sliding contact interfaces of DLC films can lead to super-low friction and wear.Incorporation of hydrogen into bulk DLC or near surface regions can be done during deposition or through hydrogen plasma treatment after the deposition.Hydrogen can also be fed into the sliding contact interfaces of DLCs during tribological testing to reduce friction.Due to favorable tribochemical interactions,these interfaces become very rich in hydrogen and thus provide super-low friction after a brief run-in period.Regardless of the method used,when sliding surfaces of DLC films are enriched in hydrogen,they then provide some of the lowest friction coefficients(i.e.,down to 0.001).Time-of-flight secondary ion mass spectrometer(TOF-SIMS)is used to gather evidence on the extent and nature of tribochemical interactions with hydrogen.Based on the tribological and surface analytical findings,we provide a mechanistic model for the critical role of hydrogen on superlubricity of DLC films.

Using Virtual ATE Model to Migrate Test Programs

Because of high development costs of IC (Integrated Circuit) test programs,recycling ekisting test programs from one kind of ATE (Automatic Test Equip-ment) to another or generating directly from CAD simulation modules to ATEis more and more vauable. In this papert a new approach to migrating test pro-grams is presented. A virtual ATE model based on object-oriellted paradigm isdeveloped; it runs Test C++ (an intermediate test control language) programsand TeIF (Test Intermediate Format - an intermediate pattern), migrates testprograms among three kinds of ATE (Ando DIC8032, Schlumberger S15 andGenRad 1732) and gellerates test patterns from two kinds of CAD (Daisy andPanda) automatically.