Today's Reliability Research Articles

Cybersecurity and Confidentiality in Smart Grid for Enhancing Sustainability and Reliability

Ensuring cybersecurity and confidentiality in smart grids is crucial for enhancing sustainability and reliability in today's technology-driven world. With the increasing reliance on smart grid technologies, it is imperative to address the potential cybersecurity risks and protect the confidentiality of sensitive data. This research focuses on exploring the challenges and strategies associated with cybersecurity and confidentiality in smart grids. It examines the importance of safeguarding smart grid infrastructure from cyber threats to maintain sustainable and reliable energy delivery systems. The study investigates various techniques and technologies, including encryption, authentication, intrusion detection, and secure communication protocols, that can be employed to enhance the cybersecurity and confidentiality of smart grids. By highlighting the significance of a robust cybersecurity framework and the integration of privacy-preserving measures, this research aims to contribute to the development of secure and resilient smart grid systems. The findings and recommendations presented in this work provide valuable insights for policymakers, industry professionals, and researchers involved in the design and implementation of secure smart grid solutions, ultimately leading to the advancement of sustainable and reliable energy infrastructures.

Future‐proofing photovoltaics module reliability through a unifying predictive modeling framework

AbstractSolar energy, especially photovoltaics (PV), plays a significant role in the global energy transition required for decarbonization. Technological advancements in increasing efficiencies coupled with cost reductions through economies of scale made PV a cost‐competitive energy source set to exceed the milestone of 1 TW globally deployed capacity in 2022. However, ongoing downward price pressure coupled with increasing service life expectations creates tremendous challenges for reliability engineers in ensuring the safe and reliable operation of PV modules and systems over the anticipated service life. Today's reliability research efforts aim for module lifetimes of up to 50 years. Still, our current tools fall short in accurately assessing degradation mechanisms and failure modes over such extended periods. We argue that the well‐established PV reliability learning cycle needs to be accelerated to keep up with the rapid technological advancements and high expectations that are put on PV and its role in the global energy transition. In this article, we explore the evolution of the PV reliability learning cycle and highlight the significance that predictive modeling capabilities will have on future PV module reliability. We propose creating a unifying modeling framework—which once established will enable the holistic assessment of PV module reliability, accelerate the PV reliability learning cycle, and bring us closer to quantitative service life predictions of PV modules.

Durability of Goods – Economic, Legal and Informational Aspects

The article studies reliability of technically complicated goods as complex customer characteristics; the most informative indicators, i.e. service life; the dependence of durability on economic characteristics of the product; trends of reducing service life of goods and possible negative economic and ecological after-effects were shown; an attempt was made to compare customer costs on different stages of the product life cycle. The authors provide requirements to manufacturers' responsibility and product sellers concerning warranty periods and service life, service support and repair of technically complicated goods, legal consequences of product breakdown within the frames of warranty periods and service life. Statistics given by Rospotrebnadzor dealing with faulty technically complicated products was analyzed. Summarized information of recommended service life and average amount of work per breakdown fixed in relative inter-state standards was provided. The stated information was compared with figures of durability and reliability in today's practice of manufacturing and selling house-hold electric machines and devices. On the basis of EU guidelines one variant of legal way of resolving the problem of attaining the optimum service life for customers and manufacturers was proposed. The authors give recommendations on fixing obligatory requirements on limiting use of short-life and difficult to utilize materials in details of technically difficult goods.

The detrimental effects of water on electronic devices

Water in its various forms can affect the performance and reliability of today's electronics in unique ways. This paper discusses the forms of water and the degradation effect of water on electronics, identifies the types of failure mechanisms in electronics induced by liquid and vapor phase water, presents case studies of water-related failures, and provides recommendations for preventing water-imposed degradation in electronics. Test methods and standards based on different forms of water and specific applications of electronics are also presented.

Cluster-Aware Scattered Repair in Erasure-Coded Storage: Design and Analysis

Erasure coding is a storage-efficient means to guarantee data reliability in today's commodity storage systems, yet its repair performance is seriously hindered by the substantial repair traffic. Repair in clustered storage systems is even complicated because of the scarcity of the cross-cluster bandwidth. We present <inline-formula><tex-math notation="LaTeX">${\sf ClusterSR}$</tex-math></inline-formula> , a cluster-aware scattered repair approach. <inline-formula><tex-math notation="LaTeX">${\sf ClusterSR}$</tex-math></inline-formula> minimizes the cross-cluster repair traffic by carefully choosing the clusters for reading and repairing chunks. It further balances the cross-cluster repair traffic by scheduling the repair of multiple chunks. Large-scale simulation and Alibaba Cloud ECS experiments show that <inline-formula><tex-math notation="LaTeX">${\sf ClusterSR}$</tex-math></inline-formula> can reduce 5.6-52.7 percent of the cross-cluster repair traffic and improve 14.4–68.8 percent of the repair throughput.

A Time-Saving Approach for the Thermal Lifetime Evaluation of Low-Voltage Electrical Machines

Modern electrical machines, such as those employed in transportation applications are required to provide very high performance in terms of power (and torque) density and efficiency. The reality, however, is that the more these machines are “pushed” in relation to power density, the more is the probability of failure of their insulation systems, through enhanced electrical and thermal stresses. On the other hand, regardless the power density level, the electrical machine still needs to respect the certification processes set by the international standards and procedures. Unfortunately, today reliability and lifetime are still not considered as main design objective functions right from the start of the design process. This is a direct result of a gap in knowledge in terms of the precise understanding of failure mechanisms. If physics of failure models are available, then reliability can be included at all design stages. Therefore, this article proposes a method that shortens the time demanded for the thermal lifetime evaluation procedure or qualification of low-voltage electrical machines. The theory behind the method is presented and, then, experimentally validated on custom designed specimens.

RELIABILITY; WHAT'S RIGHT FOR YOUR BUSINESS?

Abstract In today's high-tech world, we heavily depend on electronics for our health, safety, mobility and economic welfare. When they fail, the results can be as minor as consumer annoyance to as severe as loss of life. Not to mention a significant financial penalty to the producer in the form of warranty cost. In the electronics industry, especially in the consumer electronics segment, warranty expense cost can be 1% - 2% of the total revenue1. As an example, for a $1B company, this can impact the bottom line by $10M–$20M. For this reason, reducing warranty cost through increased product reliability is not only necessary for survival but also smart. However, achieving product reliability in today's environment with limited development resources and demand for reducing product development cycle time creates a special challenge. In addition, many small to medium size organizations struggle to understand the basic concepts behind reliability engineering, often confusing it with quality. This paper presents a lean approach to developing and implementing a reliability program that is simple, flexible and woven into a product development program.

Transient Heat Conduction in On-Chip Interconnects Using Proper Orthogonal Decomposition Method

A major challenge in maintaining quality and reliability in today's microelectronics chips comes from the ever increasing levels of integration in the device fabrication, as well as from the high current densities. Transient Joule heating in the on-chip interconnect metal lines with characteristic sizes of tens of nanometer, can lead to thermomechanical fatigue and failure due to the thermal expansion coefficient mismatch between different materials. Full-field simulations of nearly a billion interconnects in a modern microprocessor are infeasible due to the grid size requirements. To prevent premature device failures, a rapid predictive capability for the thermal response of on-chip interconnects is essential. This work develops a two-dimensional (2D) transient heat conduction framework to analyze inhomogeneous domains, using a reduced-order modeling approach based on proper orthogonal decomposition (POD) and Galerkin projection. POD modes are generated by using a representative step function as the heat source. The model rapidly predicted the transient thermal behavior of the system for several cases, without generating any new observations, and using just a few POD modes.

Intelligent control schemes applied to Automatic Generation Control

Integrating ever increasing amount of renewable generating resources to interconnected power systems has created new challenges to the safety and reliability of today‟s power grids and posed new questions to be answered in the power system modeling, analysis and control. Automatic Generation Control (AGC) must be extended to be able to accommodate the control of renewable generating assets. In addition, AGC is mandated to operate in accordance with the NERC‟s Control Performance Standard (CPS) criteria, which represent a greater flexibility in relaxing the control of generating resources and yet assuring the stability and reliability of interconnected power systems when each balancing authority operates in full compliance. Enhancements in several aspects to the traditional AGC must be made in order to meet the aforementioned challenges. It is the intention of this paper to provide a systematic, mathematical formulation for AGC as a first attempt in the context of meeting the NERC CPS requirements and integrating renewable generating assets, which has not been seen reported in the literature to the best knowledge of the authors. Furthermore, this paper proposes neural network based predictive control schemes for AGC. The proposed controller is capable of handling complicated nonlinear dynamics in comparison with the conventional Proportional Integral (PI) controller which is typically most effective to handle linear dynamics. The neural controller is designed in such a way that it has the capability of controlling the system generation in the relaxed manner so the ACE is controlled to a desired range instead of driving it to zero which would otherwise increase the control effort and cost; and most importantly the resulting system control performance meets the NERC CPS requirements and/or the NERC Balancing Authority’s ACE Limit (BAAL) compliance requirements whichever are applicable.

On BER evaluation of MIMO-OFDM incorporated wireless system

To achieve high data rates and simultaneous increase in capacity range along with reliability in today's wireless communication system, multiple input multiple output (MIMO) has been recognized as one of the most popular and competitive technique. In MIMO systems, information can be transmitted and received from multiple antennas simultaneously and making the probability of information detected precisely higher. In this paper, BER analysis of MIMO-OFDM, a technique of integrating OFDM to MIMO system to improve spectral efficiency in conjunction with ISI reduction, incorporating various modulation schemes is demonstrated. Further, the results are compared with the performance of conventional OFDM (C-OFDM) system [14,15] and reported an improvement in BER with MIMO-OFDM system.

Lifetime Reliability Enhancement of Microprocessors

Ensuring lifetime reliability of microprocessors has become more critical. Continuous scaling and increasing temperatures due to growing power density are threatening lifetime reliability. Negative bias temperature instability (NBTI) has been known for decades, but its impact has been insignificant compared to other factors. Aggressive scaling, however, makes NBTI the most serious threat to chip lifetime reliability in today's and future process technologies. The delay of microprocessors gradually increases as time goes by, due to stress and recovery phases. The delay eventually becomes higher than the value required to meet design constraints, which results in failed systems. In this article, the mechanism of NBTI and its effects on lifetime reliability are presented, then various techniques to mitigate NBTI degradation on microprocessors are introduced. The mitigation can be addressed at either the circuit level or architectural level. Circuit-level techniques include design-time techniques such as transistor sizing and NBTI-aware synthesis. Forward body biasing, and adaptive voltage scaling are adaptive techniques that can mitigate NBTI degradation at the circuit level by controlling the threshold voltage or supply voltage to hide the lengthened delay caused by NBTI degradation. Reliability has been regarded as something to be addressed by chip manufacturers. However, there are recent attempts to bring lifetime reliability problems to the architectural level. Architectural techniques can reduce the cost added by circuit-level techniques, which are based on the worst-case degradation estimation. Traditional low-power and thermal management techniques can be successfully extended to deal with reliability problems since aging is dependent on power consumption and temperature. Self-repair is another option to enhance the lifetime of microprocessors using either core-level or lower-level redundancy. With a growing thermal crisis and constant scaling, lifetime reliability requires more intensive research in conjunction with other design issues.

Community Oriented Neighboring Feedback for Efficient End-to-End Delay-Sensitive MP2P Streaming via Temporal Relay-Based Replication

Next generation peer-information systems are envisioned to be characterized by an invisible and ubiquitous lookup application support which should be easily accessible by users in a transparent and location-independent reliable fashion. Therefore, the traditional end-to-end delays should be bounded and minimized in order to offer significant increase in performance and reliability in today's Mobile Peer-to-Peer (MP2P) systems. Many parameters that affect the end-to-end delay for efficient collaborative streaming, deal with the temporal characteristics (connectivity and mobility constraints, etc). These parameters are significantly degrading the end-to-end communicational survivability and resources' availability. In this work a scheme for collaborative replication is proposed using community oriented relay regions for MP2P streaming. The proposed model considers a combined community oriented neighboring feedback approach with selective delay-centric replication taking into account the social interactions for assigning available resources to nodes that are communicating via intraclustered links. The collaborative streaming is achieved through the outsourcing file chunk policy for N-hop replicated sources and the combined community oriented model. The presented scheme is thoroughly evaluated through experimental simulation which takes measures for the end-to-end reliability and the latency of the broadcast schedule when delivering delay-sensitive MP2P streams.

Experience of Numerical Protective Relays Operating in an Environment With High-Frequency Switching Surge in Japan

This paper intends to provide general information about the experiences of numerical relay operation under many different kinds of surges from switchyards in Japan. The main focus of this paper is to investigate the immunity of numerical relays against a switching surge with relatively high frequency in a gas-insulated substation that is considered to be severe for the relay's correct operation. It is concluded that the reliability of today's numerical relays in Japan against the switching surge is almost sufficient due to the effectiveness of the immunity test standard adopted and countermeasures against the switching surge in Japan.

A fast and scalable inter-domain MPLS protection mechanism

With the fast growth of Internet and a new widespread interest in optical networks, the unparalleled potential of MultiProtocol Label Switching (MPLS) is leading to further research and development efforts. One of those areas of research is Path Protection Mechanism. It is widely accepted that layer three protection and recovery mechanisms are too slow for today's reliability requirements. Failure recovery latencies ranging from several seconds to minutes, for layer three routing protocols, have been widely reported. For this reason, a recovery mechanism at the MPLS layer capable of recovering from failed paths in 10's of milliseconds has been sought. In light of this, several MPLS based protection mechanisms have been proposed, such as end-to-end path protection and local repair mechanism. Those mechanisms are designed for intra-domain recoveries and little or no attention has been given to the case of non-homogenous independent inter-domains. This paper presents a novel solution for the setup and maintenance of independent protection mechanisms within individual domains and merged at the domain boundaries. This innovative solution offers significant advantages including fast recovery across multiple non-homogeneous domains and high scalability. Detailed setup and operation procedures are described. Finally, simulation results using OPNET are presented showing recovery times of a few milliseconds.

WebExpress: a client/intercept based system for optimizing Web browsing in a wireless environment

This paper describes an application model and software technology that makes it possible to run World Wide Web applications in wide area wireless networks. Web technology in conjunction with today's mobile devices (e.g., laptops, notebooks, personal digital assistants) and the emerging wireless technologies (e.g., digital cellular, packet radio, CDPD) offer the potential for unprecedented access to data and applications by mobile workers. Yet, the limited bandwidth, high latency, high cost, and poor reliability of today's wireless wide-area networks greatly inhibits (to the point of infeasibility) supporting such applications over wireless networks. This paper presents the Client/Intercept computational model that makes it possible to run such distributed applications efficiently in wide area wireless networks. Furthermore, it presents WebExpress, a client/intercept based system for optimizing Web browsing, that reduces data volume and latency of wireless communications by intercepting the HTTP data stream and performing various optimizations including: file caching, forms differencing, protocol reduction, and the elimination of redundant HTTP header transmission. This paper describes these optimizations and presents some experimental results.

Cyber-bricks and paradigms

The author considers how the idea of clustering has become new again. Clusters of NT computers and mass storage devices, connected locally and remotely into a single, highly scalable system, will quickly become the dominant model of enterprise computing. Over 80% of the multiserver systems today are connected for high availability. The demands of accessibility and reliability in today's Internet, intranet, and enterprise server environments increasingly require failover capability, if one server goes down, the other takes over automatically.

The reliability nomograph-graphical predictor of package/module interconnect reliability

Many computer hardware manufacturers can adequately characterize the reliability of today's solder interconnect. However, the procedure is often one requiring a lengthy and complicated accelerated test. The alternative to performing an accelerated test is the use of validated predictive models. These models can be complex requiring specialized analytical skills of the user. An alternate approach is proposed and developed here. One in which the reliability of a package/solder interconnect can be predicted through a series of coupled graphs, i.e., pkg., thermal perf/spl rarr/pkg. structural perf/spl rarr/interconnect reliability. The thermal and structural performance graphs are generated through the use a package/printed wiring board (PWB) finite element model while the interconnect reliability graph uses the Norris-Landsberg model. The coupled figures are known collectively as a nomograph. Nomographs for plastic ball grid array (PBGA), plastic quad flat packs (PQFP), thin small outline packages (TSOP), ceramic ball grid array (CBGA), and ceramic column grid array (CCGA) packages are presented.

Trends in reliability and test strategies

Software fails because it contains faults. If we could be certain that our attempts to fix a fault had been effective and that we had introduced no new faults, we would know that we had improved the software's reliability. Unfortunately, no single testing method can be trusted to give accurate results in every circumstance. There are at least two areas of uncertainty in testing. First, we cannot predict when a failure will occur as a result of choosing an input that cannot currently be processed correctly. Second, we do not know what effect fixing a fault will have on the software's reliability. Most of today's reliability models consider the software system to be a black box, using indirect measures of failure by making strong assumptions about the test cases. White-box testing measures, which are direct measures, are generally not used in software-reliability models. The assumption is that the more the program is covered, the more likely that the software is reliable. Hence we must develop new testing strategies. For example, we do not understand very well the notion of stress as it applies to software; what effect the dependence between versions of the same application has on reliability; the relationship between software reliability and white-box testing measures; and how to achieve the ultra-high reliability levels obtained through formal verification and fault-tolerance methods. These are just some of the areas for future research into improved testing strategies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Berkeley reliability tools-BERT

Berkeley reliability tools (BERT) simulates the circuit degradation (drift) due to hot-electron degradation in MOSFETs and bipolar transistors and predicts circuit failure rates due to oxide breakdown and electromigration in CMOS, bipolar, and BiCMOS circuits. With the increasing importance of reliability in today's and future technology, a reliability simulator such as this is expected to serve as the engine of design-for-reliability in a building-in-reliability paradigm. BERT works in conjunction with a circuit simulator such as SPICE in order to simulate reliability for actual circuits, and, like SPICE, acts as an interactive tool for design. BERT is introduced and the current work being done is summarized. BERT is used to study the reliability of a BiCMOS inverter chain, and performance data are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Plastic encapsulated ics in military equipment reliability prediction modelling

This paper introduces a reliability prediction model for plastic encapsulated integrated circuits to be used in professional or defence electronics applications. The first part is a comparison between different reliability prediction models: their hypotheses, assumptions and validity domains are examined; constructive criticism is made and model amendments proposed for plastic encapsulated ICs reliability prediction. The second part presents the model itself. It addresses also thermal and environmental aspects. The third part explains how numerical values are found to fill the model and how it reflects the reliability of today's state-of-the-art of plastic encapsulation. In conclusion, we present the improvements that this model can bring to reliability prediction, in the particular case of plastic packages.