Comparative Analysis Of Reliability Research Articles

Comparative analysis of the reliability of electric locomotives based on semi-Markov models of restorable systems

Based on the general theory of semi-Markov recovery processes and their application to Markov recovery processes, the applicability of stationary reliability indicators to assessing the reliability of electric locomotives with an asynchronous motor, the functioning of which is considered as a superposition of independent alternating semi-Markov processes, is shown. By calculating the main indicators of system reliability in a steady state, a comparative analysis of the operational reliability of electric locomotives with an asynchronous DC and AC motors, used respectively on the Azerbaijan and Kazakhstan railways, was carried out.

Assessing the Fatigue Life of SiC Power Modules in Different Package Structures

Advanced power module packaging technology is demanded with the commercialization of silicon carbide (SiC) power devices with superior performance. This paper presents an overview of currently available packaging structures suitable for SiC power modules that can deliver good performance during operation at a high temperature, frequency, and power density while incurring low loss at a high switching speed. Four typical structures—the common single-sided cooling package structure, and three double-sided cooling package structures—were chosen for comparative thermal reliability analysis that was conducted by using a finite element simulation. One of the double-sided cooling 3D package structures yielded good thermal performance, and was highly reliable. It not only lowered the junction temperature by using a single heat source but also reduced the stress and strain of the chip and the solder layer, respectively, by nearly 30% less than the single-sided cooling structure. In addition, the fatigue life of the solder under thermal cycling was significantly longer than in the other structures.

Comparative Reliability Analysis for Resonant Converter Operation Under Component Ageing

This article is concerned with reliability analysis in relation to optimal switching of resonant power converters, aimed at minimizing their power loss and operational temperature and, thus, reducing their lifetime degradation. In most cases, high-performance resonant converter control requires a continuous adaptation of the power device switching instances depending on the power input source, load current, or parameter variation in passive components. If the resonant converter is switched before or after the resonant swing ends, more loss is added to the system, with effects in operating temperature rise and reliability deterioration. Even if the switching frequency is adjusted to keep the output voltage constant, it may influence the operational temperature. This article is quantifying this problem with a calculation of the lifetime implication for both cases of zero voltage transition (ZVT) and zero current transition (ZCT) buck converters. A broad range of parameter variation in passive components is considered due to ageing or aggravated stress. A thorough performance (lifetime/reliability) evaluation is achieved through a comparative analysis of results obtained for resonant converters with ideal operation, resonant converters with adjusted timing due to parameter variation, and hard-switched converters without any resonance. Conclusions are formulated in the end. The results reported in this article should be of high interests to the power electronics community, given that resonant converters are used in a wide range of applications due to their ability to reduce power semiconductor losses.

An Express Methodology for Calculating the Reliability of Power Supply Systems with Autonomous Power Sources

Autonomous power sources are widely used in systems for power supply to industrial facilities, especially in the oil and gas industries that have affordable energy carriers. These sources can be used both separately and in combination with centralized power supply, as primary, backup, or emergency sources. Their operation is characterized by the features that affect power supply reliability and must be taken into account when deciding on their use in the stages of designing new power supply systems or modernizing existing ones. The use of methodology and software for calculating the reliability of systems with autonomous power sources in the stage of pre-project research can contribute to more informed decision-making. In this stage, there is no need and opportunity to consider all reliability issues in detail. Here, express methods are enough to take into account the main features of the systems functioning with autonomous or mixed power sources and to compare the proposed system options within a single methodological framework. Based on this, a methodology was developed to calculate the reliability of power supply systems with autonomous and mixed power sources. The proposed methodology employs semi-Markov random processes (Markov chains) and can be used in comparative reliability analysis of power supply options with autonomous and mixed power sources. It was implemented in software and is accompanied by an example of reliability calculation for power supply to a stationary platform for maintaining reservoir pressure in an offshore oil field.

Repeatability of Zone Averages Compared to Single-Point Measurements of Maximal Curvature in Keratoconus

To evaluate the repeatability of curvature zone averages centered on the point of maximum curvature (Kmax) compared to that of the single-point Kmax. Comparative reliability analysis. Setting: American University of Beirut Medical Center, Beirut, Lebanon. Sixty-five eyes of 65 adult keratoconus patients. Patients with other ocular disease, history of ocular surgery or trauma, and contact lens wear within 2weeks of image acquisition were excluded. Eyes were evaluated with 3 consecutive scans using the Galilei dual Scheimpflug-Placido system. Repeatability of axial and instantaneous Kmax single points, and zone averages with radii of 0.1-2.0mm, centered on them. Repeatability was assessed by within-subject standard deviations, repeatability limits (r), and intraclass correlation coefficients. Axial curvature zone averaging yielded clinically acceptable repeatability only in eyes with Kmax ≤50 diopters (D), for radii of 1.5mm and 2.0mm (r= 0.87 D and r= 0.76, respectively, vs r= 0.91 for the single-point axial Kmax). Compared to instantaneous Kmax, clinically acceptable repeatability was achieved with instantaneous zone averages of at least 1.5mm radius in eyes with Kmax ≤50 D (r= 0.99 D and r= 0.70 D, respectively) and 2.0mm radius in eyes with Kmax >50 D (r= 2.28 D and r= 0.87 D, respectively). For all eyes, the repeatability limit of the location of Kmax was 0.82mm and 0.80mm for axial and instantaneous curvature, respectively. Instantaneous curvature zone averages centered on Kmax yielded a greater improvement in repeatability than axial zone averages and reached clinical adequacy with radii of at least 1.5mm, for eyes with Kmax ≤50 D, and with a 2.0mm radius for eyes with Kmax >50 D.

Energy Storage for 1500 V Photovoltaic Systems: A Comparative Reliability Analysis of DC- and AC-Coupling

There is an increasing demand in integrating energy storage with photovoltaic (PV) systems to provide more smoothed power and enhance the grid-friendliness of solar PV systems. To integrate battery energy storage systems (BESS) to an utility-scale 1500 V PV system, one of the key design considerations is the basic architecture selection between DC- and AC-coupling. Hence, it is necessary to assess the reliability of the power conversion units, which are not only the key system components, but also represent the most reliability-critical parts, in order to ensure an efficient and reliable 1500 V PV-battery system. Thus, this paper investigates the BESS solutions of DC- and AC-coupled configurations for 1500 V PV systems with a comparative reliability analysis. The reliability analysis is carried out through a case study on a 160 kW/1500 V PV-system integrated DC- or AC-coupled BESS for PV power smoothing and ramp-rate regulation. In the analysis, all of the DC-DC and DC-AC power interfacing converters are taken into consideration along with component-, converter-, and system-level reliability evaluation. The results reveal that the reliability of the 1500 V PV inverter can be enhanced with the DC-coupled BESS, while seen from the system-level reliability (i.e., a PV-battery system), both of the DC- and AC-coupled BESSs will affect the overall system reliability, especially for the DC-coupled case. The findings can be added into the design phase of 1500 V PV systems in a way to further lower the cost of energy.

Paper Versus Digital Data Collection Methods for Road Safety Observations: Comparative Efficiency Analysis of Cost, Timeliness, Reliability, and Results.

BackgroundRoadside observational studies play a fundamental role in designing evidence-informed strategies to address the pressing global health problem of road traffic injuries. Paper-based data collection has been the standard method for such studies, although digital methods are gaining popularity in all types of primary data collection.ObjectiveThis study aims to understand the reliability, productivity, and efficiency of paper vs digital data collection based on three different road user behaviors: helmet use, seatbelt use, and speeding. It also aims to understand the cost and time efficiency of each method and to evaluate potential trade-offs among reliability, productivity, and efficiency.MethodsA total of 150 observational sessions were conducted simultaneously for each risk factor in Mumbai, India, across two rounds of data collection. We matched the simultaneous digital and paper observation periods by date, time, and location, and compared the reliability by subgroups and the productivity using Pearson correlations (r). We also conducted logistic regressions separately by method to understand how similar results of inferential analyses would be. The time to complete an observation and the time to obtain a complete dataset were also compared, as were the total costs in US dollars for fieldwork, data entry, management, and cleaning.ResultsProductivity was higher in paper than digital methods in each round for each risk factor. However, the sample sizes across both methods provided a precision of 0.7 percentage points or smaller. The gap between digital and paper data collection productivity narrowed across rounds, with correlations improving from r=0.27-0.49 to 0.89-0.96. Reliability in risk factor proportions was between 0.61 and 0.99, improving between the two rounds for each risk factor. The results of the logistic regressions were also largely comparable between the two methods. Differences in regression results were largely attributable to small sample sizes in some variable levels or random error in variables where the prevalence of the outcome was similar among variable levels. Although data collectors were able to complete an observation using paper more quickly, the digital dataset was available approximately 9 days sooner. Although fixed costs were higher for digital data collection, variable costs were much lower, resulting in a 7.73% (US $3011/38,947) lower overall cost.ConclusionsOur study did not face trade-offs among time efficiency, cost efficiency, statistical reliability, and descriptive comparability when deciding between digital and paper, as digital data collection proved equivalent or superior on these domains in the context of our project. As trade-offs among cost, timeliness, and comparability—and the relative importance of each—could be unique to every data collection project, researchers should carefully consider the questionnaire complexity, target sample size, implementation plan, cost and logistical constraints, and geographical contexts when making the decision between digital and paper.

INCREASING OF THE RELIABILITY CITY'S WATER SUPPLY SYSTEM THROUGH ZONING

The article analyzes the topical issue of assessing the reliability of water supply in Kremenchuk, Poltava region, in the zoning of the water supply system. The scheme of the integrated water supply system of Kremenchuk was built to calculate reliability, which reflects the movement of water from the source to the consumers and the main structures of the water supply system. The work of the water supply system of Kremenchuk and its structure is analyzed. In terms of reliability, it is concluded that water pipes are the least reliable element. The statistics on the failures of the water supply systems of the city of Kremenchuk are analyzed. The calculations showed that the actual failure rate for steel pipes d = 1100 mm of water pipes in Kremenchug is 2 failures per 10 km of steel pipe per year, which is 2 times higher than foreign and domestic data. The reliability assessment of both the integrated and district water supply system of Kremenchuk was performed on the failure of water supply systems for both separately connected individual elements. Comparative analysis of reliability of the integrated and district water supply system of Kremenchuk without fail has shown that the zoning significantly increases the reliability of water supply in the Kryukivsky district, and the reliability of water supply of the Avtozavodsky district remains unchanged. In the integrated system in the Kryukiv district, the parameter of the flow of failures was 1/year, that is, about 3 times a year a break in water supply is possible. In the district system, both systems operate independently, which is why everything remains unchanged in the Avtozavodsky district, and the failure flow parameter for the Kryukivsky district is significantly reduced and is: 1/year, which corresponds to a water supply interruption of about once every 2.5 years. Thus, zoning can increase the reliability of water supply in the Kryukovsky district of Kremenchuk approximately 8 times. Keywords: the water supply system, reliability, dependability, zoning.

Global practices and prospects of strategic accounting methods for the Russian banks

Fluctuating economic environment and the development of digital technologies highlight the need to update strategic accounting and analysis methods aimed at assessing the reliability of banks and ensuring their sustainable development. The article systematized modern tools for strategic accounting of banking activities, the tools being globally applied by regulatory authorities and potential investors to assess the efficiency of banking activities, to identify the areas for development and to adjust the strategy chosen by the banks, to obtain comprehensive information on the creditworthiness of credit users. The purpose of the article is to substantiate the prospects for the strategic accounting methods in the activities of the Russian banks and to develop the indicators that increase the assessment reliability in management decision making. The study shows that the challenges faced by the Russian banking practices in adapting the advanced international approaches are related to the significant differences in the business models of credit institutions, the lack of ratings for corporate governance and bank reputation, the underdeveloped assessment approaches to the creditworthiness of credit users with regard to their industry, and the lack of reporting information under IFRS. Practices of strategic accounting for banks activities are upgraded by digital technologies as simulation tools for a large number of processes and as tools aimed to reduce the number of routine operations, to improve the accuracy of calculations, to process and store large databases for effective interaction and information exchange. A comprehensive rating assessment should include both financial indicators and information characterizing the efficiency of the bank performance, its reputation, its external environment and the impact of the economic, political context, environmental and social aspects of banking activities. The novelty of the research is to substantiate the prospects for the development of strategic accounting in the banking sector and to expand the system of indicators to assess the financial condition and reliability of banks, ensuring that findings and predictive assessments are more objective for informed management and investment decision making. The results of the research can be useful for investors, banking supervision authorities, banking specialists, risk management experts, and scientists interested in developing strategic accounting tools in banks. Further research is linked to the need to solve the problem of ensuring reliability and homogeneity of information used in compiling tank ratings, as well as to develop specialized software and applications for the outside users to perform a comparative analysis of banks reliability and for the bank management to monitor activities and to adjust the development strategy.

A comparative analysis of efficiency and reliability of capacitive micro-switches with initially curved electrodes

Enhancement of both efficiency and reliability of MEMS structures has always been an interesting and even essential issue for research community. This paper provides a comparative investigation in this field focusing on the role of initially curved electrodes of capacitive micro-switches. Four models have been introduced by appliance of curved microbeams as either upper or lower electrodes of a capacitive MEMS switch, as well as the conventional base model with straight both electrodes. By introducing a mathematical model and appropriate numerical procedure, the contact area between two electrodes, which has direct effect on the reliability has been estimated using Hertz relation for all models. The electromechanical coupling factor which is related to the efficiency of the switch has been calculated considering the stored mechanical and electrical energy of the system. The results have shown that by appliance of an initial curvature to the both electrodes, the estimated contact area can increase up to 279% compared to the conventional switches. Also, a switch with straight moveable electrode and curved substrate exhibits an increase in coupling factor up to 24% compared to the base model, while increasing the pull-in voltage of the switch.

Comparative analysis of reliability of non-destructive methods of strength control of concrete impregnated with vegetable oil: Basalt fiber for increasing the concrete strength

Abstract The feature of the operation of most industrial buildings and structures is the production or use of oils and oil products in technological processes. Getting on concrete and reinforced concrete load-bearing structures, vegetable and mineral oil and oil products gradually impregnate them and cause a negative impact on physical and mechanical properties of the material. A negative impact of vegetable, mineral oil and oil products on concrete and reinforced concrete leads to the reliability reduction of load-bearing structures of industrial buildings of the certain purpose. The study presents the concrete strength determinations of pumping equipment of oil processing enterprises foundations (while in operation about 5 years). During the research the main developments in this field have been analyzed. The reliable method of strength concrete was discussed. Adding basalt fibers in concrete mixture as reinforcement helps to retain and increase the strength of concrete impregnated with vegetable oil. The properties of basalt fiber give basalt fiber reinforced concrete the ability to withstand acidic, chemical, salty effect that causes concrete structures to lose its strength. The dependences of the measured results by both methods analyzed in this paper depending on the impregnation of concrete with vegetable oil were shown. The analysis of the indicators which depend on the time of impregnation with different oils has been carried out in this paper. The obtained results can be applied to assess the technical safety of industrial buildings in which vegetable and mineral oil, and oil products are produced and used. Also, how the use of basalt fibers in reinforcing concrete cures the oil impregnated concrete and increases the concrete strength was discussed in this paper.

Low Leakage Fully Half-Select-Free Robust SRAM Cells With BTI Reliability Analysis

This paper presents two different topologies of 11T SRAM cells with fully half-select-free robust operation for bit-interleaving implementation. The proposed 11T-1 and 11T-2 cells successfully eliminate Read disturb and Write half-select disturb and also improve the Write-ability by using power-cutoff and write “0”/ “1” only techniques. The 11T-1 and 11T-2 cells achieve $1.83 \times $ and $1.7 \times $ higher write-yield while both achieve approximately $2 \times $ higher read-yield as compared with 6T cell (at ${V}_{DD} = 0.9$ V). The proposed 11T-1 cell also shows 13.6% higher mean Write-margin (WM) compared with existing 11T cell. Both the proposed cells successfully eliminate floating node condition encountered in earlier power cut-off cells during write half-select. Monte-Carlo simulation confirms low-voltage operation without any additional peripheral assist circuits. We also present a comparative analysis of Bias Temperature Instability reliability impacting the SRAM performance in a predictive 32nm high-k metal gate CMOS technology. Under static stress, the Read Static Noise Margin (RSNM) reduces for all cells. However, 11T-1 and 11T-2 cells improve RSNM by 2.7% and 3.3% under relaxed stress of 10/90. Moreover, the proposed 11T-1 (11T-2) cell improves WM by 7.2% (13.2%), reduces write power by 28.0% (20.4%) and leakage power by 85.7% (86.9%), degrades write delay by 38.1% (23.3%) without affecting read delay/power over a period of 108 seconds (approx. 3 years). The 11T-1 (11T-2) cell exhibits 4.8% higher (2% lower) area overhead as compared to earlier 11T cell. Hence, the proposed 11T cells are an excellent choice for reliable SRAM design at nanoscale amidst process variations and transistor aging effect and can also be used in bit-interleaving architecture to achieve multi-cell upset immunity.

Comparative reliability analysis of selected joints for case furniture

Specific reliability parameters are used to determine the durability and safety of a furniture structure. An experimental study was conducted to determine the probability of failure free time and compare the reliability and hazard rates of selected joints used in case furniture. The investigations were performed on samples of joints with a connector of the screw, dowel, or eccentric type. Altogether, 600 samples were tested. The reliability tests were conducted on a specially designed laboratory stand. The reliability characteristics of the individual joints were used to designate the most reliable type of joint. The hazard rate of the dowel joint was about 8 times that of the confirmat screw joint. In the case of the eccentric joint, the hazard rate was as much as 57 times higher than it was for the screw joint. The test method presented here for determining the reliability of joints aid in the selection of a connector type during case furniture design.

A comparative reliability analysis of ballistic deployments on binary asteroids

Small body missions can significantly benefit from deploying small landing systems onto the surface of the visited object. Despite the potential benefit that they may bring, deployments of landers in small body environments may entail significant mission design challenges. This paper thus addresses the potential of ballistic landing opportunities in binary asteroid moons from a mission design perspective, particularly focusing on reliability aspects of the trajectories. Two binaries that were previously identified as target bodies in several missions/proposals, Didymos and 1996 FG3, are considered in this paper. The dynamics near them are modeled by means of the Circular Restricted Three Body Problem (CR3BP), which provides a reasonable representation of a standard binary system. Natural landing trajectories that allow both minimum-velocity local-vertical touchdown and deployment from a safe distance are investigated. Coefficient of restitution values are used as a design parameter to compute the first touchdown speeds that ensure sufficient reliability of landing trajectories. A simple reliability index, which is derived via uncertainty ellipsoid from covariance analysis, is introduced to create a global reliability map across the asteroid surfaces. Assuming 3σ deployment errors on the order of 90 m and 2 cm/s, the results show that ballistic landing operations are likely to be successful for larger binary moons if the deployments target near equatorial regions within longitude range 320o–20°. It has also been shown that the deployments to smaller binary moons may require higher accuracy in navigation and deployment systems in their mothership, and/or closer deployment distances.

Reliability analysis of component-level redundant topologies for solid-state fault current limiter

ABSTRACTExperience shows that semiconductor switches in power electronics systems are the most vulnerable components. One of the most common ways to solve this reliability challenge is component-level redundant design. There are four possible configurations for the redundant design in component level. This article presents a comparative reliability analysis between different component-level redundant designs for solid-state fault current limiter. The aim of the proposed analysis is to determine the more reliable component-level redundant configuration. The mean time to failure (MTTF) is used as the reliability parameter. Considering both fault types (open circuit and short circuit), the MTTFs of different configurations are calculated. It is demonstrated that more reliable configuration depends on the junction temperature of the semiconductor switches in the steady state. That junction temperature is a function of (i) ambient temperature, (ii) power loss of the semiconductor switch and (iii) thermal resistance of heat sink. Also, results’ sensitivity to each parameter is investigated. The results show that in different conditions, various configurations have higher reliability. The experimental results are presented to clarify the theory and feasibility of the proposed approaches. At last, levelised costs of different configurations are analysed for a fair comparison.

Comparative analysis of energy parameters and OFDM-signal reliability receiving with different OFDM sub-carriers number

The effectiveness of the optimal gain for OFDM-signals is proved based on the simulation results. It’s possible to achieve an independence of the energy characteristics and information reliability of group signal generated by technology OFDM from the number of OFDM subcarriers. The paper shows how the value of the optimal gain depends on the OFDM subcarriers number. The analytical expression for determining the optimum gain is realized on the basis of an integral equation, which defines the form of the density distribution of the amplitudes of the amplified signal, and reliability requirements for signal processing, and the value is the desired one. Determination results of are the product of statistical modeling. Knowledge of the value gives you the possibility to calculate the corresponding value of the energy parameter for communication channel (signal to noise ratio) that is the basis for the subsequent analytical calculation symbol and bit error values for each value for signal to noise ratio. The proposed optimal analytical condition is realized on the basis of the solution of an integral equation in which the form of the density distribution is given by a parameter of the distribution for given values of and . The value is the desired one. Determination result for is the product of statistical modeling. If the value is known, then we have a possibility to calculate the corresponding channel parameter value , which is the basis for the subsequent analytical calculation error values and bit error for each channel parameter value value. Justified effect of the described method for forming OFDM-signal allows use this technology as a tool for multiple access communication systems such as promising LTE and other similar technologies. In addition, this property characterizes OFDM technology as potentially effective in a multipath channel, since a change in the number of subcarriers without sacrificing energy received beam allows you to control the duration of a single character, depending on the actual conditions of rays delay, reducing the impact on the quality factor of multipath reception. Reliability losses when using OFDM technology with respect to single-frequency transmission can be compensated for by the selection of an appropriate signal-code structure that containing anti-noise code with the required parameters to achieve required reliability. Reference 5, figures 11, table 1.

A Comparative Analysis of Inter-rater Reliability in English Essay and Korean-English Translation Tests

A Comparative Analysis of Inter-rater Reliability in English Essay and Korean-English Translation Tests

Difference between Vascularization Indexes of the Placenta in Severe Pre-eclampsia and Normal Pregnancy by Three-dimensional Power Doppler Ultrasound

ABSTRACT Aim The object of this study was to analyze the vascularization index of three-dimensional (3D) power Doppler ultrasound (PDUS) of the placenta in severe pre-eclampsia compared with normal pregnancy conditions by vascular biopsy sampling sphere. Subjects and methods This study is a prospective longitudinal observational study on 80 pregnant women which divided into 2 groups: Group I (study group) were 40 pregnant women with severe pre-eclampsia, group II (control group) were 40 pregnant women without disorder. Variables examined in this study were vascular index (VI), flow index (FI) and vascular flow index (VFI) of the 3D-PD placental perfusion. Its correlation to gestational age in normal pregnancy compared with the condition of preeclampsia were obtained by taking multiple biopsy sampling vascular sphere. All pregnant women underwent 3D PD-US examination (single examination only), data volume recorded of the placenta allows for off-line analysis without the presence of the patient, thus allowing the data analysis done anywhere and anytime by observers for the comparative analysis of interobserver reliability. Results The placenta can be visualized perfectly in both of the study group and also the control group. Average Kappa value for the acquisition of placental vascularization index measurements with 3D PD-US was 0.72 (0.61-0.82), 0.73 (0.65-0.82) and 0.71 (0.61-0.81) for VI, FI and VFI in the range of 20 to 38 weeks showed good interobserver reliability. All 3D power Doppler indices had a significant association with gestational age, with VI showed a less significant relationship (r = 0.207, p = 0.0139) and FI has the most significant relationship (r = 0.582, p < 0.001). FI index increased progressively with gestational age, while the VI index values indicate dispersion pattern and reached a plateau from week 30 onwards. Entering week 37th, there was a decrease in the value of the index VI until the end of pregnancy. Meanwhile, VFI index appears to resemble the pattern of a combination of both VI and FI index (r = 0.692, p <0.001). Conclusion All parameters of 3D power Doppler index was lower in the severe pre-eclampsia compared with normal pregnancy. 3D PD-US can be used to assess the vascularization of the placenta and the intensity of intra-placental blood flow. Placental vascular biopsy method is fairly efficient way to perform routine evaluations evolution of placental vascular branch during pregnancy. How to cite this article Andonotopo W, Kristanto H, Dewantiningrum J, Pramono BA. Difference between Vascularization Indexes of the Placenta in Severe Pre-eclampsia and Normal Pregnancy by Three-dimensional Power Doppler Ultrasound. Donald School J Ultrasound Obstet Gynecol 2014;8(4):329-335.

A Time-domain Modeling and Simulation Framework for Comparative Analysis of Prognostics, Reliability and Robustness in System Design


 
 
 Redundancy is an effective, high-level solution to the requirement for reliable safety-critical systems, but it comes at the cost of Size, Weight and Power (SWaP) and reduced capability. A modeling and simulation framework was developed to address the need for robust design alternatives to redundancy. Robustness, in our application, is treated as the insensitivity of the performance with reference to specification. The necessity to characterize both reliability and robustness in the same framework has resulted in a time-domain simulation approach to modeling behaviors associated with unreliability and a lack of robustness. The incorporation of these features offers a novel insight into potential applications of prognostic technology. Further development of this approach has the potential to allow designers to choose how risks associated with failures are mitigated, by redundancy, robustness, or prognosis.
 By modeling the life of parts, the factors that impact them and the resulting behaviors, the observability and predictability (even controllability in the case of optimized, fault-tolerant, closed-loop control) of faults and failures is identified. Designers can determine which parts of a system would benefit from prognostic health management (PHM) technologies, adaptive / tolerant features to yield robust design, or redundancy based approaches. The complex causality in the models requires a Monte Carlo approach analogous to the simulation of fleets of systems; this, combined with the ability to simulate systems made from new and old parts, can inform strategies for condition-based maintenance (CBM). We present the mathematical modeling concept and the simulation framework which permits comparative assessment of reliability, robustness and prognostics. The multi-hierarchical, systems integration aspects inherent to the concept make this technique highly applicable to real- world dynamic systems. The framework also supports statistical, standards based and physics-of-failure descriptions of stress, aging, fault and failure behaviors in a unified way. There are challenges to be overcome in realizing the benefits of this approach to model-based system design. Issues of model validation, data availability and computational burden are recognized and discussed. As we show, these challenges can be overcome to produce new design tools providing better products and transparent project quality.
 
 

Correction: Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging

Correction: Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging