We have investigated, in various multiple senses, the “capacity” of several models of erasure networks. The defining characteristic of a memoryless erasure network is that each channel between any two nodes is an independent erasure channel. The models that we explore differ in the absence or presence of interference at either the transmitters, the receivers, or both; and in the availability of feedback at the transmitters. The crux of this work involves the investigation and analysis of several different performance measures for these networks: traditional information capacity (including multicast capacity and feeback capacity), secrecy capacity, and transport capacity. / text

Text in Afrikaans / Plaaslike owerhede sal met die devolusie van politieke mag tot op derdevlakregering 'n groter rol in die bepaling van die toekoms van dorpe en stede speel. Binne die raamwerk van nasionale sekuriteit het plaaslike owerhede as werkgewers en eienaars van geboue, 'n besondere verantwoordelikheid om na die beveiliging van mense, die handhawing en voortsetting van dienste en die beskerming van raadseiendom om te sien. Omdat plaaslike owerhede regsoutonoom is, word sekuriteitsafdelings op sy eie manier bedryf wat nie noodwendig die koste-effektiefste en doeltreffendste wyse is nie. Die uitbreiding van private en publieke sekuriteitsdienste noodsaak die ordelike ontwikkeling en koordinering van dienste aan die hand van standaard-aanvaarbare voorskrifte. In die ondersoek is 'n houdingstudie na die aard, omvang, plek, beeld, status, funksies en opleiding van blanke plaaslike owerheidsekuriteitsbeamptes geloods in 'n poging om 'n basis te vestig ten einde plaaslike owerheidsekuriteit op 'n gesonde grondslag te bedryf. / The devolution of political power to local authority level obliges local authorities to play a greater role in determining the future of cities and towns. Within the framework of national security, local authorities as employers and owners of property have a responsibility towards the safeguarding of people, the upholding and continuation of services and the protection of council property. As legal autonomous bodies, local authorities manage their security departments in their own peculiar way which is not necessarily the most cost effective and efficient. The expansion of private and public security services necessitates orderly development and coordination of services with reference to prescribed acceptable standards. This research is an attitudinal study of the nature, scope, place, image, status, functions and training of white local authority security officers in an attempt to establish a point of departure in order to facilitate the sound managing of local authority security. / Police Practice / M.A. (Polisiekunde)

CAPES / Vídeos digitais se tornaram uma forma de comunicação altamente utilizada na rede, entretanto estes dados são facilmente copiados e distribuídos. Isto se deve ao crescente número de ferramentas que surgiram com este objetivo, causando quebra dos direitos autorais e distribuição ilegal de conteúdo. A solução mais estudada para este problema são as marcas d'água digitais, que provêm segurança em forma de autenticação e verificação de violação. Neste trabalho, foi desenvolvido um novo método de inserção e extração de marcas d'água em um vídeo, usando o processo chamado abordagem lateral. Este possibilita a marcação em blocos de frames. As diversas marcas inseridas são usadas como redundância para aumentar a robustez contra ataques. Os testes realizados seguiram o padrão dos benchmarks Vidmark e Stirmark, os quais demonstram a eficiência do método em manter a marca d'água mesmo após ataques. / Digital videos have become the most used way to communicate, however these data are easily copied and distributed. That happen due the growing number of tools that are create with this goal, causing breach of copyright and illegal distribution of content. The most studied solution that can solve this problem are the digital watermarks that provide security like authentication and tamper detection. In this work, we developed a new method of embedding and extracting watermarks in a video using a process called side view. This process allows watermark a block of frames. The several watermarks embedded can be used like redundance to grow the robustness of the method against attacks. The tests followed the standard benchmarks Vidmark and Stirmark that show the performance of the method in keep the watermark even after attacks.

Orientadores: Leonardo de Souza Mendes, Mario Lemes Proença Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T19:18:19Z (GMT). No. of bitstreams: 1 Zarpelao_BrunoBogaz_D.pdf: 5089650 bytes, checksum: 281e7d926aae4a7e05a2e94347a06179 (MD5) Previous issue date: 2010 / Resumo: Anomalias em redes de computadores são desvios súbitos e acentuados que ocorrem no tráfego em consequência de diversas situações como defeitos em softwares, uso abusivo de recursos da rede, falhas em equipamentos, erros em configurações e ataques. Nesta tese, é proposto um sistema de detecção de anomalias em redes de computadores baseado em três níveis de análise. O primeiro nível de análise é responsável por comparar os dados coletados em um objeto SNMP (Simple Network Management Protocol) com o perfil de operações normais da rede. O segundo nível de análise correlaciona os alarmes gerados no primeiro nível de análise utilizando um grafo de dependências que representa as relações entre os objetos SNMP monitorados. O terceiro nível de análise reúne os alarmes de segundo nível utilizando informações sobre a topologia de rede e gera um alarme de terceiro nível que reporta a propagação da anomalia pela rede. Os testes foram realizados na rede da Universidade Estadual de Londrina, utilizando situações reais. Os resultados mostraram que a proposta apresentou baixas taxas de falsos positivos combinadas a altas taxas de detecção. Além disso, o sistema foi capaz de correlacionar alarmes gerados para diferentes objetos SNMP em toda a rede, produzindo conjuntos menores de alarmes que ofereceram ao administrador de redes uma visão panorâmica do problema / Abstract: Anomalies in computer networks are unexpected and significant deviations that occur in network traffic due to different situations such as software bugs, unfair resource usage, failures, misconfiguration and attacks. In this work, it is proposed an anomaly detection system based on three levels of analysis. The first level of analysis is responsible for comparing the data collected from SNMP (Simple Network Management Protocol) objects with the profile of network normal behavior. The second level of analysis correlates the alarms generated by the first level of analysis by using a dependency graph, which represents the relationships between the SNMP objects. The third level of analysis correlates the second level alarms by using network topology information. The third level generates a third level alarm that presents the anomaly propagation path through the network. Tests were performed in the State University of Londrina network, exploring real situations. Results showed that the proposal presents low false positive rates and high detection rates. Moreover, the proposed system is able to correlate alarms that were generated for SNMP objects at different places of the network, producing smaller sets of alarms that offer a wide-view of the problem to the network administrator / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

This thesis is an investigation into the unique rural banking system in Ghana and the role of information systems in fraud control. It presents a robust information security and internal control model to deal with fraud for the banking system. The rural banking industry has been noted for poor internal control leading to fraud. This has resulted in poor performance and even the collapse of some banks. The Focus of the study was on the processes used to deliver banking services. To design a protection system, a number of rural banks were visited. This was to understand the environment, regulatory regimes and the structure and banking processes of the industry and banks. Systemic vulnerabilities within the industry which could be exploited for fraud were found. The lack of structures like an address system and unreliable identification documents makes it difficult to use conventional identification processes. Also the lack of adequate controls, small staff numbers and the cross organisational nature of some transactions among other cultural issues reduces the ability to implement transaction controls. Twenty fraud scenarios were derived to illustrate the manifestation of these vulnerabilities. The rural banking integrity model was developed to deal with these observations. This protection model was developed using existing information security models and banking control mechanisms but incorporating the nature of the rural banking industry and culture of its environment. The fraud protection model was tested against the fraud scenarios and was shown to meet the needs of the rural banking industry in dealing with its systemic vulnerabilities. The proposed community-based identification scheme deals with identification weaknesses as an alternative to conventional identity verification mechanisms. The Transaction Authentication Code uses traditional adinkra symbols. Whilst other mechanisms like the Transaction Verification Code design v internal controls into the banking processes. This deals with various process control weaknesses and avoids human discretion in complying with controls. Object based separation of duties is also introduced as a means of controlling conflicting tasks which could lead to fraud.

The researcher attempts to establish how CCTV footage can be used as a surveillance technique, for evidence gained in that way to be admissible in court. To conduct effective investigation, it is important for investigators to be familiar with the application of CCTV footage, its purpose, its benefits and shortfalls. To achieve the goals and objectives of the practice of CCTV footage, investigators must know how to utilise the value of its evidence, and how to use it to identify suspects. The clarification and application to the crime situation, the identification of the perpetrator or suspect of a criminal act is mostly impossible, if CCTV footage is not available to assist in identification and tracing of suspects. / Police Practice / M. Tech. (Forensic Investigation)

This study investigates the causes of fear of crime amongst residents of Ward 33 in KwaZulu-Natal, and the impact of this fear on their behaviour; the relationship between social cohesion and fear of crime; how residents are trying to make themselves safer in their own homes; and whether these measures are indeed producing feelings of greater safety and security. The research methodology employed for this dissertation is mainly qualitative, in particular the use of storytelling and photographs, which were used as a “canopener” to get respondents to discuss their security choices as well as the choices made by others. The findings indicate that the sources and extent of fear of crime vary amongst residents. Fear of crime emanates from the physical and social environment as well as the kinds of information shared within communities. Embedded within the narratives is a strong association of race with crime, which is deepening divisions in the ward. The findings also question whether greater heterogeneity automatically reduces social cohesion. As far as home security is concerned, the northern part of the ward is generally more affluent and this is reflected in the more diverse security measures adopted by residents. In discussing the principles of Crime Prevention Through Environmental Design (CPTED), which is based on the idea that crimes are less likely to occur when properties are visible, residents’ attitudes tended to vary according to their respective fear of crime, their financial status, and specific location within the ward. A theme running consistently through the literature and in some of the narratives is the effect of geography on how residents and potential criminals view an area. The regeneration of some parts of the ward and neglect of others shows the differential outcomes when local community members choose whether or not to be proactive and participate in such projects. / Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2013.

Orientador: Paulo Lício de Geus / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-16T05:27:31Z (GMT). No. of bitstreams: 1 Cavalcante_GabrielDieterich_M.pdf: 3073328 bytes, checksum: aeb145421a7f9c0c3d3ac872eb9ac054 (MD5) Previous issue date: 2010 / Resumo: Existe uma grande quantidade de configurações presentes em sistemas atuais e gerir essas configurações é um trabalho árduo para qualquer administrador de sistema. Inúmeras configurações podem ser definidas para uma só máquina e as combinações entre elas implicam de forma significativa no seu desempenho. A partir do momento que um sistema em pleno funcionamento pára de funcionar, algo em sua estrutura pode ter mudado. Este cenário é comum no processo de desenvolvimento de software onde o código fonte pode deixar de compilar ou ainda uma funcionalidade pode se perder. Controladores de versão são usados para reverter o estado do código para uma data anterior, solucionando o problema. Verificadores de Integridade são utilizados para detectar estas mudanças, porém não possuem mecanismos específicos para recuperação. Este estudo propõe e implementa uma arquitetura integrada que combina verificação de integridade e mecanismos de recuperação. Foram executados testes para determinar a sobrecarga total deste método, além de estudos de caso para verificar a sua eficiência de recuperação / Abstract: Current computer systems have a huge number of configurations that are hard to manage. The combinations of system configurations can impact on performance and behavior. From the moment that a system stops working correctly it is remarkable that something has changed. That is in common in software development, where changes made by the programmer may result in some features no longer working or the project not compiling anymore. Revision control systems can recover a previous state of the source code through revision mechanisms. Integrity checking is used to catch file modifications, however this technique does nothing toward recovering those files. This study proposes and implements an integrated architecture that combines integrity checking and restoring mechanisms. Tests were executed in order to measure the load imposed by the solution. In addition, analysis of three case studies shows the efficiency of the adopted solution / Mestrado / Segurança de Computadores

Submitted by Andre Untem (andre.untem@gmail.com) on 2012-12-19T16:03:46Z No. of bitstreams: 1 AndreOkamotoUntem_VersaoFinal.pdf: 2195184 bytes, checksum: 69027860a1e2b638618a529983245436 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2012-12-20T16:09:39Z (GMT) No. of bitstreams: 1 AndreOkamotoUntem_VersaoFinal.pdf: 2195184 bytes, checksum: 69027860a1e2b638618a529983245436 (MD5) / Made available in DSpace on 2012-12-20T16:10:00Z (GMT). No. of bitstreams: 1 AndreOkamotoUntem_VersaoFinal.pdf: 2195184 bytes, checksum: 69027860a1e2b638618a529983245436 (MD5) Previous issue date: 2012-06-25 / In this work, we will present a series of general and partial equilibrium models that deals with human capital accummulation, social security systems, labor supply and retirement. We willanalyse the relations between different mechanisms of human capital accummulation and productivity; relations between uncertaints and hypothesis about credit markets; and the influence of those variables on households' decision of retirment. / Neste trabalho, serão apresentados artigos que abordam modelos de equilíbrio geral e parcial que tratem da acumulação de capital humano, sistemas de previdência, oferta de trabalho e aposentadoria. São feitas análises entre diferentes mecanismos de acumulação humano e sua relação com produtividade; relações entre incertezas e hipóteses sobre mercados de crédito; e.a in uência dessas variáveis na aposentadoria das pessoas.

This thesis deals with automation of buildings, provides the possibility of automation in today's intelligent buildings. The issue of building automation for security and access systems is solved in details. This thesis contains the basic rules of the systems and procedure in the implementation of access and security systems. The target of this thesis is the proposal of the access and security system for buildings. Part of the thesis is also creating a model, on which will be presented the access and security system. This model will be used by the company ELMONT GROUP as a basis for dealing with contracts.