Root Cause Analysis of a Printed Circuit Board (PCB) Failure in a Public Transport Communication System

A printed circuit board (PCB) is an essential element for practical circuit applications and its failure can inflict large financial costs and even safety concerns, especially if the PCB failure occurs prematurely and unexpectedly. Understanding the failure modes and even the failure mechanisms of a PCB failure are not sufficient to ensure the same failure will not occur again in subsequent operations with different batches of PCBs. The identification of the root cause is crucial to prevent the reoccurrence of the same failure. In this work, a step-by-step approach from customer returned and inventory reproduced boards to the root cause identification is described for an actual industry case where the failure is a PCB burn-out. The failure mechanism is found to be a conductive anodic filament (CAF) even though the PCB is CAF-resistant. The root cause is due to PCB de-penalization. A reliability verification to assure the effectiveness of the corrective action according to the identified root cause is shown to complete the case study. This work shows that a CAF-resistant PCB does not necessarily guarantee no CAF and PCB processes can render its CAF resistance ineffective.

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.

Estimating the Mode of Delivery through Cause Analysis A Systematic Literature Review on the context of Reducing Cesarean

In developing countries, many health workers force pregnant women in private hospitals having baby through cesarean delivery, even though most pregnant mothers are skeptical about the risk of going under such operations. Doctors often encourage pregnant mothers to have a cesarean on the basis of their physical condition and medical reports. Emergency cesarean patient cannot be prepared in advance but on real time, If a system can be developed that can forecast whether a woman need natural or cesarean delivery, then rate of the risk of the pregnant women get reduce. To design such system, we need to know what factors influences the doctors to choose cesarean over normal delivery. We have conducted a systematic review in well-known databases to understand the various factors of pregnant mothers. A total of 19 studies were selected among 2512 studies based on the relevancy to the research objective. The objective of this study is to predict the mode of delivery based on 10 specific parameters identified separately from 180 parameters present in various test reports.

The Role of Root Cause Analysis (RCA) in Power Distribution Network Interruption Reduction

Responsibility and reliability are very important for electricity subscribers. Due to their extent, these networks face a variety of challenges, and most of them are recurring but can be prevented if the root causes are identified. One of the methods to identify the root of network problems is to use the RCA method in the analysis of blackouts. RCA is an approach that systematically investigates adverse events and, by gathering evidence and documentation, finds its root causes and offers solutions to address them. Finally, it monitors the implementation of solutions and evaluates their effectiveness. In this chapter, while introducing some of the challenges of medium voltage power supply networks, the root of the problems are extracted, and corrective solutions are presented in three sample problematic feeders. After extracting the solutions, they are divided into two categories: the first category is the solutions specific to the sample feeder, and the second category is the solutions that can be generalized to other parts of the power supply network.