A data analytic approach to automatic fault diagnosis and prognosis for distribution automation

Distribution Automation (DA) is deployed to reduce outages and to rapidly reconnect customers following network faults. Recent developments in DA equipment have enabled the logging of load and fault event data, referred to as ‘pick-up activity’. This pick-up activity provides a picture of the underlying circuit activity occurring between successive DA operations over a period of time and has the potential to be accessed remotely for off-line or on-line analysis. The application of data analytics and automated analysis of this data supports reactive fault management and post fault investigation into anomalous network behavior. It also supports predictive capabilities that identify when potential network faults are evolving and offers the opportunity to take action in advance in order to mitigate any outages. This paper details the design of a novel decision support system to achieve fault diagnosis and prognosis for DA schemes. It combines detailed data from a specific DA device with rule-based, data mining and clustering techniques to deliver the diagnostic and prognostic functions. These are applied to 11kV distribution network data captured from Pole Mounted Auto-Reclosers (PMARs) as provided by a leading UK network operator. This novel automated analysis system diagnoses the nature of a circuit’s previous fault activity, identifies underlying anomalous circuit activity, and highlights indications of problematic events gradually evolving into a full scale circuit fault. The novel contributions include the tackling of ‘semi-permanent faults’ and the re-usable methodology and approach for applying data analytics to any DA device data sets in order to provide diagnostic decisions and mitigate potential fault scenarios

Concurrency Control in Multidatabases

Computer Science

Permanent Injunctions in Defamation Actions

Permanent injunctions prohibiting defamatory speech are increasingly sought and ordered following a finding of liability. This may seem unproblematic since a court will have found the particular speech to be unlawful—defamatory and likely false. However, there are good reasons to be cautious in permanently enjoining defamatory speech. This article shows that courts have recognized a test for permanent injunctions in defamation cases based on a misinterpretation of the case law—a test which is inconsistent with first principles of equitable relief. It then proposes a number of guidelines and principles for permanent injunctive relief in defamation actions. Most proposals relate to ensuring that an injunction is actually necessary to prevent future reputational harm, while some are more innovative and perhaps controversial, such as creating a serious harm requirement and precluding injunctions where comment rather than fact is at issue. It is also a plea to lawyers and especially judges not to be too quick to seek or impose injunctions simply because defamatory speech is published online. Les injonctions permanentes interdisant les propos diffamatoires sont de plus en plus souvent demandées et ordonnées à la suite d’un constat de responsabilité. Cela ne semble pas poser de problème puisque le tribunal a estimé que les propos tenus étaient illégaux, diffamatoires et probablement faux. Cependant, il y a de bonnes raisons d’être prudent dans l’interdiction permanente des propos diffamatoires. Cet article montre que les tribunaux ont reconnu un critère pour les injonctions permanentes dans les affaires de diffamation basé sur une interprétation erronée de la jurisprudence—un critère qui est incompatible avec les premiers principes de la réparation équitable. Il propose ensuite un certain nombre de lignes directrices et de principes pour les injonctions permanentes dans les actions en diffamation. La plupart des propositions visent à garantir qu’une injonction est réellement nécessaire pour empêcher une atteinte future à la réputation, tandis que d’autres sont plus novatrices et peut-être controversées, comme la création d’une exigence de préjudice grave et l’exclusion des injonctions lorsque ce sont des commentaires plutôt que des faits qui sont en cause. Il s’agit également d’un appel aux avocats et surtout aux juges pour qu’ils ne soient pas trop prompts à demander ou à imposer des injonctions simplement parce que des propos diffamatoires sont publiés en ligne

A Localized Autonomous Control Algorithm For Robots With Heterogeneous Capabilities In A Multi-Tier Architecture

This dissertation makes two contributions to the use of the Blackboard Architecture for command. The use of boundary nodes for data abstraction is introduced and the use of a solver-based blackboard system with pruning is proposed. It also makes contributions advancing the engineering design process in the area of command system selection for heterogeneous robotic systems. It presents and analyzes data informing decision making between centralized and distributed command systems and also characterizes the efficacy of pruning across different experimental scenarios, demonstrating when it is effective or not. Finally, it demonstrates the operations of the system, raising the technology readiness level (TRL) of the technology towards a level suitable for actual mission use. The context for this work is a multi-tier mission architecture, based on prior work by Fink on a “tier scalable” architecture. This work took a top-down approach where the superior tiers (in terms of scope of visibility) send specific commands to craft in lower tiers. While benefitting from the use of a large centralized processing center, this approach is limited in responding to failures and interference. The work presented herein has involved developing and comparatively characterizing centralized and decentralized (where superior nodes provide information and goals to the lower-level craft, but decisions are made locally) Blackboard Architecture based command systems. Blackboard Architecture advancements (a solver, pruning, boundary nodes) have been made and tested under multiple experimental conditions

An Analytical Model for Evaluating Database Update Schemes

A methodology is presented for evaluating the performance of database update schemes. The methodology uses the M/Hr/1 queueing model as a basis for this analysis and makes use of the history of how data is used in the database. Parameters have been introduced which can be set based on the characteristics of a specific system. These include update to retrieval ratio, average file size, overhead, block size and the expected number of items in the database. The analysis is specifically directed toward the support of derived data within the relational model. Three support methods are analyzed. These are first examined in a central database system. The analysis is then extended in order to measure performance in a distributed system. Because concurrency is a major problem in a distributed system, the support of derived data is analyzed with respect to three distributive concurrency control techniques -- master/slave, distributed and synchronized. In addition to its use as a performance predictor, the development of the methodology serves to demonstrate how queueing theory may be used to investigate other related database problems. This is an important benefit due to this lack of fundamental results in the area of using queueing theory to analyze database performance