3D Simulation of Partial Discharge in High Voltage Power Networks

Open accessPartial discharge (PD) events arise inside power cables due to defects of cable’s insulation material, characterized by a lower electrical breakdown strength than the surrounding dielectric material. These electrical discharges cause signals to propagate along the cable, manifesting as noise phenomena. More significantly, they contribute to insulation degradation and can produce a disruptive effect with a consequent interruption of power network operation. PD events are, therefore, one of the best ‘early warning’ indicators of insulation degradation and, for this reason, the modeling and studying of such phenomena, together with the development of on-line PDs location methods, are important topics for network integrity assessment, and to define methods to improve the power networks’ Electricity Security. This paper presents a 3D model of PD events inside a void in epoxy-resin insulation cables for High Voltage (HV) power networks. The 3D model has been developed using the High Frequency (HF) Solver of CST Studio Suite® software. PD events of a few µs duration have been modelled and analyzed. The PD behavior has been investigated using varying electrical stress. A first study of the PD signal propagation in a power network is described

A User-Focused Reference Model for Wireless Systems Beyond 3G

This whitepaper describes a proposal from Working Group 1, the Human Perspective of the Wireless World, for a user-focused reference model for systems beyond 3G. The general structure of the proposed model involves two "planes": the Value Plane and the Capability Plane. The characteristics of these planes are discussed in detail and an example application of the model to a specific scenario for the wireless world is provided

In Search for the Right Measure: Assessing Types of Developed Knowledge While Using a Gamified Web Toolkit

Game-based learning has been used to teach topics in diverse domains, but it is still hard to determine when such approaches are an efficient learning technique. In this paper we focus on one open challenge – the limited understanding in the community of the types of knowledge these games help to develop. Using a taxonomy that distinguishes between declarative, procedural and conditional knowledge, we evaluate a game-based toolkit to analyse and solve an information security problem within a holistic crime prevention framework. Twenty-eight participants used the toolkit. We designed a portfolio of learning assessment measures to capture learning of different types of knowledge. The measures included two theoretical open-answer questions to explore participants' understanding, three problem-specific open-answer questions to test their ability to apply the framework, and 9 multiple-choice questions to test their ability to transfer what was learned to other contexts. The assessment measures were administered before and after use of the tookit. The application questions were analysed by classifying suggested ideas. The theoretical questions were qualitatively analysed using a set of analytical techniques. The transferability questions were statistically analysed using ttests. Our results show that participants' answers to the application questions improved in quality after the use of the toolkit. In their answers to the theoretical questions most participants could explain the key features of the toolkit. Statistical analysis of the multiple-choice questions testing transferability however failed to demonstrate significant improvement. Whilist our participants understood the CCO framework and learned how to use the toolkit, participants didn't demonstrate transfer of knowledge to other situations in information security. We discuss our results, limitations of the study design and possible lessons to be learned from these

Permissions Snapshots: Assessing Users' Adaptation to the Android Runtime Permission Model

The Android operating system changed its security and privacy-related permission model recently, offering its users the ability to control resources that applications are allowed to access on their devices. This major change to the traditional coarse-grained permission system was anticipated for a long time by privacy-aware users. This paper presents the first study that analyzes Android users' adaptation to the fine-grained runtime permission model, regarding their security and privacy controls. We gathered anonymous data from 50 participants who downloaded our application and answered questions related to the new permission model. The results indicate that the majority of users prefer the new model. We also collected data that demonstrate users' security controls at the given time. Our analysis shows that individuals make consistent choices regarding the resources they allow to various applications to access

Transmission of primary resistance mutation K103N in a cluster of Belgian young patients from different risk groups

Background: We analysed the distribution of an HIV-1 subtype B strain resistant to efavirenz and nevirapine among incident infections in the Belgian population. Method: The Belgian AIDS reference laboratories searched their databases for HIV-1 subtype B sequences harbouring the K103N mutation in the reverse transcriptase (RT) or the C67S and V77I mutations in the protease (PR). We included the earliest RT sequence available of drug-naïve patients as well as sequences related to treatment failure. Fifty sequences were aligned omitting the codon 103 and submitted to phylogenetic analysis. Epidemiological data were collected through the Institute of Public Health national database. In addition, three sequences from the cluster were analysed by deep sequencing using the Roche GS Junior platform. Results: Phylogenetic analysis revealed the presence of a 24 virus sequences cluster. All except one of those sequences resulted from patients who were ARV-naïve at the time of sampling, and 21 had the K103N mutation. Two thirds of the clustered patients were infected through homosexual or bisexual contacts while the others were heterosexuals. No case was related to migrants contaminated abroad. Fifteen of the clustered patients were diagnosed between January 2011 and June 2012; 87% of them were aged between 20 and 29 at the time of diagnosis. Interestingly, 60% of them reside in the province of Namur. Deep sequencing analysis of 3 individuals sampled near seroconversion revealed no other resistance mutations at a frequency > 1% than those already picked up by Sanger sequencing (RT A98S, K103N; PR V77I), except the RT V90I. Conclusion: We identified a transmission cluster of drug resistant HIV-1 variants mainly including homo- and heterosexual young adults. Most individuals are of Belgian origin and are living around the city of Namur (Belgium). The K103N mutation had no apparent impact on transmission fitness as its spread raised during the last years. These observations may impact on local prevention and ARV prophylaxis strategies

Accounting for Taste: Using profile similarity to improve recommender systems

Recommender systems have been developed to address the abundance of choice we face in taste domains (films, music, restaurants) when shopping or going out. However, consumers currently struggle to evaluate the appropriateness of recommendations offered. With collaborative filtering, recommendations are based on people's ratings of items. In this paper, we propose that the usefulness of recommender systems can be improved by including more information about recommenders. We conducted a laboratory online experiment with 100 participants simulating a movie recommender system to determine how familiarity of the recommender, profile similarity between decision-maker and recommender, and rating overlap with a particular recommender influence the choices of decision-makers in such a context. While familiarity in this experiment did not affect the participants' choices, profile similarity and rating overlap had a significant influence. These results help us understand the decision-making processes in an online context and form the basis for user-centered social recommender system design

Immunization Coverage and Surveillance: Challenges for the Poliomyelitis Global Eradication Initiative

In May 1988 the Forty-first World Health Assembly committed WHO to the global eradication of poliomyelitis by the year 2000 (Resolution WHA41.28). Global eradication, as has been achieved for smallpox, can be defined as the complete and permanent cessation of the natural transmission of an infectious-disease agent. The broad objectives of the global poliomyelitis eradication initiative are to achieve, by the year 2000, no case of clinical poliomyelitis associated with wild poliovirus, and no wild poliovirus identified worldwide through sampling of communities and the environment. Global poliomyelitis eradication will be highly beneficial. Apart from the huge benefit associated with the control of the disease - more than 200,000 cases of paralytic poliomyelitis are estimated to occur each year - the main cost savings for all countries, developed as well as developing, would be provided by abandoning poliomyelitis immunization. In the United States alone, the expected savings are estimated to be $114 million per year. However, because of the epidemiological features of poliomyelitis, all control efforts directed at the disease can be dropped only when worldwide eradication has been achieved and certified. Two of the main problems to solve before global eradication can be realized are how to implement and maintain a) high-coverage immunization programs and b) effective surveillance systems all over the world. The purpose of this paper is to review the progress and the remaining problems in these two key areas.Master of Public Healt

Information security as organizational power: A framework for re-thinking security policies

Successful enforcement of information security requires an understanding of a complex interplay of social and technological forces. Drawing on socio-technical literature to develop an analytical framework, we examine the relationship between security policies and power in organizations. We use our framework to study three examples of security policy from a large empirical study n an international company. Each example highlights a different aspect of our framework. Our results, from in-depth interviews with 55 staff members at all levels, show that there is often non-compliance in the detail of organizational information security policies; this is not willful but is in response to shortcomings in the policy and to meet business needs. We conclude by linking our findings to recent research on the institutional economics of information security. We suggest ways in which our framework can be used by organizational decision-makers to review and re-think existing security policies

Usability is a policy issue: Minimising the "Hassle Factor" in mobile payment of the Central London Congestion Charge

This paper presents a study of user responses to the implementation of a high-profile egovernment system, the Central London Congestion Charge. The approach is multi-disciplinary, combining human-computer interaction (HCI) and socio-technical systems (STS) approaches to produce an analysis of usability in the payment interactions. Based on interviews with charge payers, we show that usability is an issue in the payment of the charge; this is compounded by the short time-scale enforced with penalties, and the resulting perception is of an adversarial system. SMS is a possible payment route, but currently social and policy reasons work against it. In some social contexts, the simplicity of SMS is appropriate, whereas in others, the familiarity and richer functionality of the Internet and phone are more usable