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A novel method based on the analytical multi-physics simulation to predict the lifetime for LED systems is presented in this paper. LED is a typical multidisciplinary system that transfers electrical input into photonic output, and lifetime prediction is a must for new electronic device before releasing to market. The lifetime feature of LED systems is closely connected to the power, thermal, and...
In this work, a physics-of-failure (PoF) reliability prediction methodology is combined with statistical models to consider the interaction between the lumen depreciation and catastrophic failures of LEDs. The current in each LED may redistribute when the catastrophic failure occurs in one of LEDs in an array, thus affecting the operation conditions of the entire LED array. A physics-of-failure based...
GaAs space solar cells always suffered from the complex and hostile space environment. Space solar cell reliability is crucial factor to ensure the normal operation of space satellites. A method of modeling the degradation of GaAs space solar cells is proposed here. The method is to find one crucial performance parameter to depict the degradation process. By applying compound Poisson process and general...
In this paper, a new condition-based maintenance method of game for the aircraft fleet is proposed. In hope of successfully deploying the aircraft fleet, some game rules are set, which prompts the generation of maintenance strategy. And the problem is transformed into a multi-phased combinatorial optimization problem. Then an algorithm of multi-stage sequential game that based on state backtracking...
The heat dissipation is a crucial factor for the reliability of high power white LEDs(HPLEDs). In this paper, a novel thermal pad structure is presented for HPLEDs, a theoretic thermal transfer model is built to analyze the thermal transferring in LED component. Besides, the thermal simulations of the LED component with the typical or the novel thermal pad are conducted, the temperature distributions...
Lumen decay of LEDs is affected by time, junction temperature and input current. In LED lamps, both temperature and input current vary with time due to driver's degradation and temperature change of lamps. This paper proposes a lumen decay prediction method which considers effects of operation time, temperature and current by taking the interaction of LED and driver performance into account. In particular,...
In this paper, a systematic approach for reliability assessment of electrolytic capacitor-free LED drivers is developed to investigate the failure rate of MOSFETs in the drivers. An original fly-back driver with electrolytic capacitor and two modified electrolytic capacitor-free drivers are studied, and their performances are compared. Due to LED lumen depreciation during operation, current of the...
This paper investigates a controller that ensures minimum operating dc-link voltage of a back-to-back converter system. The dc-link voltage adapts its reference based on the system state, reference given by an outer loop to the dc-link voltage controller. The operating dc-link voltage should be kept as low as possible to increase the power conversion efficiency and increase the reliability of converters...
Many problems have existed in synthesis design of reliability, maintainability, supportability (RMS) and performance, such as RMS design activities are numerous and optional, variable feedback branches can satisfy same RMS requirement, some iteration among RMS and Performance activities is necessary, and many uncertainty exist in the design process. A process reengineering method for synthesis design...
The quality (or reliability) cannot be qualified for high reliable microelectronic devices (failure rate less than 10−6/h) through qualification and quality conformance procedures in military standard. A method of quantitative qualification is proposed based on the distribution of degraded tests parameters for Destructive Physical Analysis (DPA). Firstly, based on the 5005.2 method (qualification...
For products which are required for long-term storage, it's difficult to assess their reliability or life extension due to lack of historical usage data or test data. This paper presents a life extension assessment method based on the accelerated storage degradation test (ASDT) and the degradation model with random performance parameters. The typical failure modes and mechanisms of hermetically sealed...
The solder joint is one of the key weakness points that influence the reliability of MEMS package, for maximum stress-strain will be produced under high-g impact, which may result in plastic distortion or even crack in solder joint. Based on the dynamic analysis of Finite Element Model (FEM), sensitivity analysis is conducted on a typical MEMS package (Leadless Chip Carrier, LCC) for the dependence...
300 samples from 21 organizations in Meizhou were surveyed through questionnaire investigation(Effective ones are 208, accounting for 69.33%).The research carried on reliability analysis and validity analyses using the SPSS software. This research also executed regression analysis on the independent variable indexes and the extracted performance indexes. The result shows, strategic human resource...
The Internet based educational systems is playing more and more important role in the modern education systems. In the system, one of the key problems is the network test management system and its security. In this paper, we introduce a network test management system based on certification authority and security transmission mechanism.
Prognostics and health management (PHM) is a methodology that permits the reliability of a system to be evaluated in its actual life cycle conditions in order to predict when and where failures will occur and to mitigate system risks. In this paper we discuss the benefits of prognostics in systems. These benefits relate to system design and development, reliability, safety, maintainability, logistics...
A multi-attribute decision making method for the general scheme of weapon equipment which aims at the system effectiveness is proposed in this paper. This method considers the stochastic confidence interval characteristics of reliability and maintainability. The objective set of alternatives is established according to the attributes-based measuring method for effectiveness. The random distance functions...
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