Fault Tree-Based Root Cause Analysis Used to Study Mal-Operation of a Protective Relay in a Smart Grid

This chapter presents how root cause analysis based on fault tree technique can be used to study mal-operation of protective relay in a smart power grid. This approach is used to identify disturbances first and root cause of mal operation of protective relays which may lead to unnecessary tripping and hence to blackout. Once the critical root causes are identified, mitigation measures first such as blocking protection functions and digital filters may be used in view of increasing the reliability of the considered protection system. The proposed approach has many advantages as it allows obtaining an important quantitative figure (security). These permits to strongly strengthen the elements of the protecting system which are most likely appropriate to failure and hence the impact on the overall system's cost is significant. Another main advantage is that it takes into account the reliability of the software part of the system which is considered to have a significant contribution in the overall reliability of the protecting system.

Methodology for Developing a Usability Assessment Questionnaire in Spanish as a Bilingual Strategy for Software Improvement

Usability is the characteristic of a software product of being effective and efficient and producing satisfaction for users and traditionally is assessed through questionnaires but most of them are only available in English. A software usability assessment questionnaire (SUAQ) is proposed in two languages: Spanish and English. The methodology comprises four stages: 1) questionnaire development, 2) administration, 3) statistical validation, and 4) sample size determination. Twenty items were evaluated in terms of clarity, consistency, and relevancy. Then, the SUAQ was administered to 95 respondents. Overall, reliability values were acceptable in Spanish and English version, respectively. The factor analysis was feasible since the KMO index, and the Bartlett sphericity test was statistically significant. Both versions of SUAQ were tested to determine their validity. The findings show that the proposed methodology is an effective usability assessment instrument and thus an effective software improvement tool from a bilingual approach.

Integrity Assessment of Pipelines Failures

The proactive maintenance of pipelines through condition based monitoring, plays an essential role in improving their overall reliability and availability. Their criticality can also be assessed by conducting reliability analysis such as FMECA, which helps in identifying relevant failure modes and averting catastrophic failures to sustain economic growth. This paper will focus on an integrity assessment set up for pipelines and the potential failure modes associated are evaluated and mitigated by determining the risk triggers. The outcome of this research has shown the various threats associated with pipelines, having an effective integrity assessment program will help mitigate such threats. Keywords: Risk Assessment, Corrosion, FMECA, Risk Priority, Failure, Inspection, Regulations, Pipelines, Monitoring

Hierarchical Interfaces as Fracture Propagation Traps in Natural Layered Composites

Compared with their monolithic version, layered structures are known to be beneficial in the design of materials, especially ceramics, providing enhanced fracture toughness, mechanical strength, and overall reliability. This was proposed in recent decades and extensively studied in the engineering literature. The source of the property enhancement is the ability of layered structures to deflect and often arrest propagating cracks along internal interfaces between layers. Similar crack-stopping abilities are found in nature for a broad range of fibrillary layered biological structures. Such abilities are largely governed by complex architectural design solutions and geometries, which all appear to involve the presence of various types of internal interfaces at different structural levels. The simultaneous occurrence at several scales of different types of interfaces, designated here as hierarchical interfaces, within judiciously designed layered composite materials, is a powerful approach that constrains cracks to bifurcate and stop. This is concisely described here using selected biological examples, potentially serving as inspiration for alternative designs of engineering composites.

Fine-mapping from summary data with the "Sum of Single Effects" model

In recent work, Wang et al introduced the "Sum of Single Effects" (SuSiE) model, and showed that it provides a simple and efficient approach to fine-mapping genetic variants from individual-level data. Here we present new methods for fitting the SuSiE model to summary data, for example to single-SNP z-scores from an association study and linkage disequilibrium (LD) values estimated from a suitable reference panel. To achieve this we introduce a simple strategy that could be used to extend any individual-level data method to deal with summary data. In essence, this strategy replaces the usual regression likelihood with an analogous likelihood based on summary data, exploiting the close connection between the two. Our strategy also has the benefit of dealing automatically with non-invertible LD matrices, which arise frequently in fine-mapping applications, and can complicate inference. We highlight other common practical issues in fine-mapping with summary data, including problems caused by inconsistencies between the z-scores and LD estimates, and we develop diagnostics to identify these inconsistencies. We also present a new refinement procedure that improves model fits in some data sets, and hence improves overall reliability of the SuSiE fine-mapping results. Simulation studies show that SuSiE applied to summary data is competitive, in both speed and accuracy, with the best available fine-mapping methods for summary data.

Establishment of Reliability of the Occupation-Based Practice Assessment

The profession’s foundational construct; occupation, is therapeutically effective, but there remains inconsistent use as a therapeutic medium. A psychometrically strong tool can measure and maximize the use of occupation. This study establishes preliminary psychometric properties of the Occupation-Based Practice Assessment (OBPA). This methodological study tested inter-rater reliability using simulated video cases to examine the OBPA. Overall reliability was acceptable with at .868. All subsections were acceptable including Meaning and Purposeful Occupation (.871), Therapeutic Intent (.819), and Engaged Participation (.807). Two items, Context (.946) and Actual Doing (.981), demonstrated excellent reliability; while three items, Meaning (.747), Adaptation (.799), and Participation (.735), fell slightly below the acceptable level. Preliminary investigation of the OBPA reveals acceptable inter-rater reliability and suggests potential for use following additional in-vivo testing to measure therapeutic interactions to enhance student learning, optimize clinical practice, facilitate professional development, evaluate programs, and quantify occupation-based practice in research.

Effect of Aging on the Properties of Intermetallic Layers in SAC+Bi Solder Joints

A major problem faced by electronic packaging industries is the poor reliability of lead free solder joints. One of the most common methods utilized to tackle this problem is by doping the alloy with other elements, especially bismuth. Researches have shown Bismuth doped solder joints to mostly fail near the Intermetallic (IMC) layer rather than the bulk of the solder joint as commonly observed in traditional SAC305 solder joints. An understanding of the properties of this IMC layer would thus provide better solutions on improving the reliability of bismuth doped solder joints. In this study, the authors have used three different lead free solders doped with 1%, 2% and 3% bismuth. Joints of these alloys were created on copper substrates. The joints were then polished to clearly expose the IMC layers. These joints were then aged at 125 °C for 0, 1, 2, 5 and 10 days. For each aging condition, the elastic modulus and the hardness of the IMC layers were evaluated using a nanoindenter. The IMC layer thickness and the chemical composition of the IMC layers were also determined for each alloy at every aging condition using Scanning Electron Microscopy (SEM) and EDS. The results from this study will give a better idea on how the percentage of bismuth content in lead free solder affects the IMC layer properties and the overall reliability of the solder joints.

Emotional Intelligence and Job Performance of the Teaching Employees at University of Bohol, Tagbilaran City

Emotional Intelligence (EI) is the ability to appraise and express one’s emotions, appraise and recognize the emotion of others, regulate one’s emotion, and use the emotion to facilitate one’s performance. Job performance of teaching employees refers to the instructional skills, personal & social qualities, educational leadership, and executive ability of the teachers, which is evaluated by the employees and their respective department/office head. This study was designed to examine the correlation between EI and job performance of the teaching employees. The study utilized a descriptive quantitative survey method using standardized questionnaires in gathering the data. The study respondents comprised 111 full-time teaching regular employees in different departments of the University of Bohol. This study used the Wong and Law Emotional Intelligence Scale with overall reliability between 0.77-0.91, which measured the EI of the respondents. Results displayed a significant positive correlation between EI and job performance. This study implies that as EI increases, the job performance of the teaching employees also increases. Moreover, the job performance between self-evaluation and office head evaluation does not significantly differ. This research indicates that the evaluation scores have no difference in how the teaching employees rated themselves and their respective office/department heads.

Unmanned Platform Design Methodology

Remotely operated and unmanned facilities offer significant safety, environmental and economic benefits over conventional facilities. This paper describes the key elements for successful design and an approach for evaluating the reliability, availability and TOTEX of unmanned facilities. The approach was developed during the concept and FEED phases of a wellhead platform project and forms the basis of the unmanned strategy going forwards but can also be used for facilities with partial processing topsides. During the design of a recent platform it became clear that normal FMEA/RAM analysis was not suitable for assessing the reliability and availability of unmanned facilities with low visit frequency. Drawing on previous experience, a new approach was developed to address the specific challenges of low maintenance intervals and provide a methodical approach to proving reliability. The new approach improved confidence in the predicted availability by identifying key components and appropriate reliability data. The process adds some extra steps to typical reliability and availability assessment, which are designed to address the specific demands of unmanned operations. The result of this work has given a clearer understanding of how reliability can be assessed and managed for low-manned or unmanned applications. The methodology helps to identify unmanned /low manned opportunities and provides guidance on design and reliability assessment It is observed that system reliability is usually driven by a few key components and that whilst many components have good overall reliability data this may not be applicable for the proposed specific operating environment and maintenance regime of an unmanned platform. It is therefore essential to evaluate components individually for their specific applications. It is concluded that to achieve the unmanned goal it is vital to fully understand the system and component reliability early in the project. The proposed methodology can be applied at any stage to validate the design, confirm assumptions, or identify gaps.

White-Box and Black-Box Reliability Modeling Framework: Integration Through Analytical Model and User Profile Validation via Deep Learning — A Practitioner’s Approach

Software reliability evaluation of complex systems is always a challenging task with conventional methods comprising both functional as well as nonfunctional aspects of real-world applications. Prevailing model frameworks moreover apply a nonfunctional approach (black-box model) that is modeled on defect data or through a functional approach (white-box model) that uses component or state-based interactions. Also, other challenges involve integrating both approaches, and validating user profiles of software operation. Further, reliability assessment is one among the most important and desirable qualities of service requirements of software systems, particularly in monitoring critical business transactions. Here, we propose a model framework to evaluate the overall reliability estimation involving both functional and nonfunctional model analyses using: (a) white-box assessment based on intercomponent analysis via component-based Cheung’s model and user profile validations with one of the identified deep learning techniques and (b) black-box modeling evaluation via generalized stochastic Petri nets based on orthogonal defect classification. A newly introduced deep learning model using white-box analysis is validated with pertinent usage profiles to establish a new trend in artificial neural networks and as well with software reliability estimation. Additionally, we introduce and present a quantitative technique — analytical hierarchy — to integrate reliability assessment and provide weights to the white-box and as well for black-box approaches to quantify overall reliability estimation. The proposed framework is illustrated with an application case study.