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51.
Assume that the probability density function for the lifetime of a newly designed product has the form: [H(t)/Q()] exp{–H(t)/Q()}. The Exponential(), Rayleigh, WeibullW(, ) and Pareto pdf's are special cases.Q() will be assumed to have an inverse Gamma prior. Assume thatm independent products are to be tested with replacement. A Bayesian Sequential Reliability Demonstration Testing plan is used to eigher accept the product and start formal production, or reject the product for reengineering. The test criterion is the intersection of two goals, a minimal goal to begin production and a mature product goal. The exact values of various risks and the distribution of total number of failures are evaluated. Based on a result about a Poisson process, the expected stopping time for the exponential failure time is also found. Included in these risks and expected stopping times are frequentist versions, thereof, so that the results also provide frequentist answers for a class of interesting stopping rules.This research was supported by NSF grants DMS-8703620 and DMS-8923071, and forms part of the Ph.D. Thesis of the first author, the development of which was supported in part by a David Ross grant at Purdue University. The authors thank the editors and a referee for insightful comments and suggestions. 相似文献
52.
Karol Jankowski Danuta Rutkowska Andrzej Rutkowski 《Theoretical chemistry accounts》1978,48(2):119-125
It is shown that the Galerkin-Petrov method if applied in a controlled way yields reliable results for excited states of the
same symmetry classifications as the ground state. Computations are performed for the 21
S and 31
S states of He. The problem of optimizing nonlinear parameters of the basis functions by means of the GP method is discussed.
A special optimization scheme is suggested and numerically illustrated for someS states of He. 相似文献
53.
G. D. Manetto C. La Rosa D. M. Grasso D. Milardi 《Journal of Thermal Analysis and Calorimetry》2005,80(2):263-270
Summary We assessed the applicability of the extrapolation procedure at infinite scanning rate to differential scanning calorimetry (DSC) data related to irreversible protein unfolding. To this aim, an array of DSC curves have been simulated on the basis of the Lumry-Eyring model N↔U→F. The results obtained confirmed that when the apparent equilibrium constant Kapp (T=T1/2) is lower than 3, the application of the extrapolation procedure provides accurate thermodynamic parameters. Although this procedure applies only to monomeric proteins for which the Lumry-Eyring model is a reasonable approximation, it will hopefully contribute to increase the potential of DSC in obtaining reliable thermodynamic information regarding the folding/unfolding equilibrium. 相似文献
54.
Carmen Luna Concepción Lloreda Juan F. Almagro Bello Jaime Botella Maria J. Orts Ana Gozalbo 《Mikrochimica acta》2004,145(1-4):121-127
Non-metallic inclusions in steel are formed due to interactions between liquid steel and its environment in the melting shop (refractories and slags). Particles not trapped in the slag remain in the cast steel, impairing steel properties in service. Inclusion composition varies and certified standards covering the whole compositional range are unavailable.The present study describes the preparation of a set of homogeneous, glassy and crystalline standards with a wide compositional range for use in analysing non-metallic steel inclusions. For this, materials were designed based on knowledge of the compositional range of interest in the Al2O3–SiO2–CaO–MgO–CaF2 system, which is the matrix of the most frequent steel inclusions. The composition and microstructural homogeneity of the reference materials was verified. 相似文献
55.
单一在线式UPS供电系统的供电方式不能满足电信分公司计费帐务中心网络设备的需求,为此对莆田市电信分公司计费帐务中心网络的供电进行了分析与改造,提出了双总线供电系统方案,提高计算机系统供电的安全性。 相似文献
56.
本文基于模糊数学的有关原理,论述了网络环境不确定的条件下路由问题的求解.本文假定网络链路延迟是模糊数,给出了路径延迟小于端到端延迟约束的可信度的定义,提出了路径可信度判定(Path Reliability Decision:PRD),最优可信度路由(Most Optimal Reliability Path:MORP),最优路径分解(Path Optimal Partition:POP),及最优分解路径(Most Optimal Partition Path:MOPP)等问题.本文证明,PRD是多项式可解的,POP可以用等可信度分解实现,一般情况下,MORP和MOPP是等价的.在所有链路延迟的宽度都相同时,MORP转化为约束为跳数的最短路径问题,因此是多项式可解的.最后我们给出了MORP的近似算法,算法的时间复杂度为O(log(ε)-1(vlog(v)+e)). 相似文献
57.
58.
《Microelectronics Reliability》2014,54(9-10):1867-1871
Power cycle reliability of Cu nanoparticle joint has been studied for high temperature operation of power devices. Al2O3 heater chips and Cu–65 wt% Mo baseplates were joined by Cu nanoparticles and Sn–0.7Cu and power cycle tests of 65/200 °C and 65/250 °C were carried out on the joints. The Cu nanoparticles were prepared by reducing Cu carbonate in ethylene glycol with dodecanoic acid + dodecyl amine (C12) and decanoic acid and decyl amine (C10) as capping agents. A power cycle test of 65/200 °C did not inflict severe damage on the Cu nanoparticle joints so that there were not many cracks formed after 3000 cycles. Vertical cracks were formed in the C12 Cu nanoparticle joint after 3000 cycles of 65/250 °C test, however the maximum temperature during the power cycle test did not change at all because vertical cracks did not have an effect on preventing heat flow. On the contrary, lateral cracks were completely formed in the Sn–0.7Cu soldered joint after 200 cycles of 65/200 °C test and in the C10 Cu nanoparticle joint after 360 cycles of 65/250 °C test. In these experiments, the maximum temperatures were rapidly increased because heat conduction was prevented across the formed lateral cracks. 相似文献
59.
60.
One-chip measurements without modifying the physical structure of packaged integrated circuits such as field-programmable gate arrays (FPGA) is challenging. This paper proposes a sensor for detecting the radio frequency interference (RFI) on the supply inside the FPGA chip. The core of the sensor is a ring oscillator built with FPGA look-up tables. The paper proposes a model to predict the response of the ring oscillator to power supply RFI, and shows that the normalized frequency shift of the ring oscillator resulting from the interference is determined by the amplitude of the interference. This relationship is independent of the interference frequency and the size of the ring oscillator. To verify the model, simulations on transistor-level look-up tables of 130-nm and 40-nm technologies were performed. The simulation results matched well with the model. In addition to simulation, an FPGA test board was fabricated. Measurements of FPGA RFI response were performed and the results were consistent with the theoretical model. The effect of the interference on the ring oscillator provided a mechanism to detect the amplitude of the supply interference on the FPGA chip. The frequency of the ring oscillator was monitored through the supply pin by measuring the spectrum of the supply noise. The properties of the sensor, such as constant response in a wide frequency range, insensitiveness to the oscillator size, ease of implementation, and minimal modification requirement of the physical structure, made it suitable for performing on-chip FPGA measurements. 相似文献