" With the increase in traffic on the web, popular web sites get a large number of requests. Servers at these sites are sometimes unable to handle the large number of requests and clients to such sites experience long delays. One approach to overcome this problem is the distribution or replication of content over multiple servers. This approach allows for client requests to be distributed to multiple servers. Several techniques have been suggested to direct client requests to multiple servers. We discuss these techniques. With this work we hope to study the extent and method of content replication and distribution at web sites. To understand the distribution and replication of content we ran client programs to retrieve headers and bodies of web pages and observed the changes in them over multiple requests. We also hope to understand possible problems that could face clients to such sites due to caching and standardization of newer protocols like HTTP/1.1. The main contribution of this work is to understand the actual implementation of replicated and distributed content on multiple servers and its implication for clients. Our investigations showed issues with replicated and distributed content and its effects on caching due to incorrect identifers being send by different servers serving the same content. We were able to identify web sites doing application layer switching mechanisms like DNS and HTTP redirection. Lower layers of switching needed investigation of the HTTP responses from servers, which were hampered by insuffcient tags send by servers. We find web sites employ a large amount of distribution of embedded content and its ramifcations on HTTP/1.1 need further investigation. "

The phenomenal growth in the use of the World Wide Web often places a heavy load on networks and servers, threatening to increase Web server response time and raising scalability issues for both the network and the server. With the advances in the field of optical networking and the increasing use of broadband technologies like cable modems and DSL, the server and not the network, is more likely to be the bottleneck. Many clients are willing to receive a degraded, less resource intensive version of the requested content as an alternative to connection failures. In this thesis, we present an adaptive content delivery system that transparently switches content depending on the load on the server in order to serve more clients. Our system is designed to work for dynamic Web pages and streaming multimedia traffic, which are not currently supported by other adaptive content approaches. We have designed a system which is capable of quantifying the load on the server and then performing the necessary adaptation. We designed a streaming MPEG server and client which can react to the server load by scaling the quality of frames transmitted. The main benefits of our approach include: transparent content switching for content adaptation, alleviating server load by a graceful degradation of server performance and no requirement of modification to existing server software, browsers or the HTTP protocol. We experimentally evaluate our adaptive server system and compare it with an unadaptive server. We find that adaptive content delivery can support as much as 25% more static requests, 15% more dynamic requests and twice as many multimedia requests as a non-adaptive server. Our, client-side experiments performed on the Internet show that the response time savings from our system are quite significant.

Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2018-08-08T13:46:16Z No. of bitstreams: 1 ElianadosSantosSilvaDissertacao2018.pdf: 1382293 bytes, checksum: 82b978b68d65d30e8554dc6a7cdd2099 (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2018-08-08T13:46:31Z (GMT) No. of bitstreams: 1 ElianadosSantosSilvaDissertacao2018.pdf: 1382293 bytes, checksum: 82b978b68d65d30e8554dc6a7cdd2099 (MD5) / Made available in DSpace on 2018-08-08T13:46:31Z (GMT). No. of bitstreams: 1 ElianadosSantosSilvaDissertacao2018.pdf: 1382293 bytes, checksum: 82b978b68d65d30e8554dc6a7cdd2099 (MD5) Previous issue date: 2018-06-29 / One of the great challenges in the world of work today, in the national and international scenario, is the generation of jobs. In this context, the public career has been singled out by many as an alternative to dodging unemployment and the candidates for public office as more advantageous than the careers of private initiative for offering, so far, stability, better labor benefits and less results and pressur9es. The present study aimed to analyze the perception of a public management analyst of the Federal Public Prosecution Service (MPU) on the relationship between professional training and the performance of work activities. The analysis of this study is part of a qualitative and exploratory approach . Its theoretical weight was anchored in the ideas of Sennett, Gaulejac and Saviani, among others. The methodological procedures for the generation of data were made through documentary research and semi-structured interviews, submitted to content analysis, according to Minayo. The results, to highlight some, showed that in the perception of the respondents there is no close relationship between higher education and work performance, as well as underutilization of analysts' potential, generating discontent and suffering, and that the meaning of the work goes through the desire for delivery good results for the institution and society. Challenges of the public sector: managing the public thing effectively. Educate its professionals to deliver better results to society. Develop professional training programs consistent with the needs of the institution and expectations of its servers. / Um dos grandes desafios no mundo do trabalho hodiernamente, no cenário nacional e internacional, é a geração de empregos. Nesse contexto, a carreira pública tem sido apontada por muitos como alternativa para driblar o desemprego e pelos candidatos a um cargo público como mais vantajosa do que as carreiras da iniciativa privada por oferecer, até o momento, estabilidade, melhores benefícios trabalhistas e menos cobrança por resultados e pressões. A presente pesquisa objetivou analisar qual é a percepção de um analista de gestão pública do Ministério Público da União - MPU sobre a relação entre formação profissional e o desempenho das atividades laborais.A análise desse estudo inserese em uma abordagem qualitativa e do tipo exploratória. Seu lastro teórico ancorou-se nas ideias de Sennett, Gaulejac e Saviani, dentre outros. Os procedimentos metodológicos para a geração de dados se deu por meio de pesquisa documental e entrevista semiestruturadas, submetidas à análise de conteúdo, segundo Minayo. Os resultados, para destacar alguns, evidenciaram que na percepção dos pesquisados não há estreita relação entre formação superior e desempenho laboral, bem como existe um subaproveitamento do potencial dos analistas, gerando descontentamentos e sofrimentos, e que o sentido do trabalho passa pelo desejo de entrega de bons resultados para a instituição e sociedade. Desafios do setor público: gerenciamento da coisa pública de forma eficaz.Educar seus profissionais para a entrega de melhores resultados para a sociedade.Desenvolver programas de formação profissional condizentes com as necessidades da instituição e expectativas de seus servidores.

In recent years, the web has switched from using the unencrypted HTTP protocol to using encrypted communications. Primarily, this resulted in increasing deployment of TLS to mitigate information leakage over the network. This development has led many web service operators to mistakenly think that migrating from HTTP to HTTPS will magically protect them from information leakage without any additional effort on their end to guar- antee the desired security properties. In reality, despite the fact that there exists enough infrastructure in place and the protocols have been “tested” (by virtue of being in wide, but not ubiquitous, use for many years), deploying HTTPS is a highly challenging task due to the technical complexity of its underlying protocols (i.e., HTTP, TLS) as well as the complexity of the TLS certificate ecosystem and this of popular client applications such as web browsers. For example, we found that many websites still avoid ubiquitous encryption and force only critical functionality and sensitive data access over encrypted connections while allowing more innocuous functionality to be accessed over HTTP. In practice, this approach is prone to flaws that can expose sensitive information or functionality to third parties. Thus, it is crucial for developers to verify the correctness of their deployments and implementations. In this dissertation, in an effort to improve users’ privacy, we highlight semantic flaws in the implementations of both web servers and clients, caused by the improper deployment of web encryption protocols. First, we conduct an in-depth assessment of major websites and explore what functionality and information is exposed to attackers that have hijacked a user’s HTTP cookies. We identify a recurring pattern across websites with partially de- ployed HTTPS, namely, that service personalization inadvertently results in the exposure of private information. The separation of functionality across multiple cookies with different scopes and inter-dependencies further complicates matters, as imprecise access control renders restricted account functionality accessible to non-secure cookies. Our cookie hijacking study reveals a number of severe flaws; for example, attackers can obtain the user’s saved address and visited websites from e.g., Google, Bing, and Yahoo allow attackers to extract the contact list and send emails from the user’s account. To estimate the extent of the threat, we run measurements on a university public wireless network for a period of 30 days and detect over 282K accounts exposing the cookies required for our hijacking attacks. Next, we explore and study security mechanisms purposed to eliminate this problem by enforcing encryption such as HSTS and HTTPS Everywhere. We evaluate each mechanism in terms of its adoption and effectiveness. We find that all mechanisms suffer from implementation flaws or deployment issues and argue that, as long as servers continue to not support ubiquitous encryption across their entire domain, no mechanism can effectively protect users from cookie hijacking and information leakage. Finally, as the security guarantees of TLS (in turn HTTPS), are critically dependent on the correct validation of X.509 server certificates, we study hostname verification, a critical component in the certificate validation process. We develop HVLearn, a novel testing framework to verify the correctness of hostname verification implementations and use HVLearn to analyze a number of popular TLS libraries and applications. To this end, we found 8 unique violations of the RFC specifications. Several of these violations are critical and can render the affected implementations vulnerable to man-in-the-middle attacks.

During the last few years, Service-Oriented Architecture (SOA) has been considered to be the new phase in the evolution of distributed enterprise applications. Even though there is a common acceptance of this concept, a real problem hinders the widespread use of SOA : A methodology to design and build secure service-oriented applications is needed. In this dissertation, we design a novel process to secure service-oriented applications. Our contribution is original not only because it applies the MDA approach to the design of service-oriented applications but also because it allows their securing by dynamically applying security patterns throughout the whole process. Security patterns capture security knowledge and describe security mechanisms. In our process, we present a structured map of security patterns for SOA and web services and its corresponding catalog. At the different steps of a software lifecycle, the architect or designer needs to make some security decisions. / An approach using a decision tree made of security pattern nodes is proposed to help making these choices. We show how to extract a decision tree from our map of security patterns. Model-Driven Architecture (MDA) is an approach which promotes the systematic use of models during a system's development lifecycle. In the dissertation we describe a chain of transformations necessary to obtain secure models of the service-oriented application. A main benefit of this process is that it decouples the application domain expertise from the security expertise that are both needed to build a secure application. Security knowledge is captured by pre-defined security patterns, their selection is rendered easier by using the decision trees and their application can be automated. A consequence is that the inclusion of security during the software development process becomes more convenient for the architects/designers. / A second benefit is that the insertion of security is semi-automated and traceable. Thus, the process is flexible and can easily adapt to changing requirements. Given that SOA was developed in order to provide enterprises with modular, reusable and adaptable architectures, but that security was the principal factor that hindered its use, we believe that our process can act as an enabler for service-oriented applications. / by Nelly A. Delessy. / Thesis (Ph.D.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, FL : 2008 Mode of access: World Wide Web.

Yeung Siu Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 52-53). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgement --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Multi-Key Encryption Theory --- p.7 / Chapter 2.1 --- Reversible Parametric Sequence --- p.7 / Chapter 2.2 --- Implementation of ARPSf --- p.11 / Chapter 3 --- Multimedia Proxy: Architectures and Protocols --- p.16 / Chapter 3.1 --- Operations to Request and Cache Data from the Server --- p.16 / Chapter 3.2 --- Operations to Request Cached Data from the Multimedia Proxy --- p.18 / Chapter 3.3 --- Encryption Configuration Parameters (ECP) --- p.19 / Chapter 4 --- Extension to multi-level proxy --- p.24 / Chapter 5 --- Secure Multimedia Library (SML) --- p.27 / Chapter 5.1 --- Proxy Pre-fetches and Caches Data --- p.27 / Chapter 5.2 --- Client Requests Cached Data From the Proxy --- p.29 / Chapter 6 --- Implementation Results --- p.31 / Chapter 7 --- Related Work --- p.40 / Chapter 8 --- Conclusion --- p.42 / Chapter A --- Function Prototypes of Secure Multimedia Library (SML) --- p.44 / Chapter A.1 --- CONNECTION AND AUTHENTICATION --- p.44 / Chapter A.1.1 --- Create SML Session --- p.44 / Chapter A.1.2 --- Public Key Manipulation --- p.44 / Chapter A.1.3 --- Authentication --- p.45 / Chapter A.1.4 --- Connect and Accept --- p.46 / Chapter A.1.5 --- Close Connection --- p.47 / Chapter A.2 --- SECURE DATA TRANSMISSION --- p.47 / Chapter A.2.1 --- Asymmetric Reversible Parametric Sequence and En- cryption Configuration Parameters --- p.47 / Chapter A.2.2 --- Bulk Data Encryption and Decryption --- p.48 / Chapter A.2.3 --- Entire Data Encryption and Decryption --- p.49 / Chapter A.3 --- Secure Proxy Architecture --- p.49 / Chapter A.3.1 --- Proxy-Server Connection --- p.49 / Chapter A.3.2 --- ARPS and ECP --- p.49 / Chapter A.3.3 --- Initial Sever Encryption --- p.50 / Chapter A.3.4 --- Proxy Re-Encryption --- p.51 / Chapter A.3.5 --- Client Decryption --- p.51 / Bibliography --- p.52

Submitted by Joana Azevedo (joanad@id.uff.br) on 2017-06-27T17:33:14Z No. of bitstreams: 1 Dissert Adriano Carvalho de Souza.pdf: 2163720 bytes, checksum: 2f9e8ca1facc98a36c0f6604d5587c7a (MD5) / Approved for entry into archive by Biblioteca da Escola de Engenharia (bee@ndc.uff.br) on 2017-07-26T13:41:04Z (GMT) No. of bitstreams: 1 Dissert Adriano Carvalho de Souza.pdf: 2163720 bytes, checksum: 2f9e8ca1facc98a36c0f6604d5587c7a (MD5) / Made available in DSpace on 2017-07-26T13:41:04Z (GMT). No. of bitstreams: 1 Dissert Adriano Carvalho de Souza.pdf: 2163720 bytes, checksum: 2f9e8ca1facc98a36c0f6604d5587c7a (MD5) / No começo do novo milênio uma nova geração de trabalhadores adentra os quadros do serviço público: a geração Y. Pela primeira vez na história, três gerações de servidores trabalham juntos no poder executivo federal: Baby Boomers, Geração X e Geração Y. Cada geração possui características e atitudes peculiares que as diferenciam, o que, por vezes, leva a um clima de tensão no ambiente organizacional. Este trabalho tem por objetivos identificar se, e de que modo, as diferenças de características e as de atitudes geracionais são relevantes enquanto fonte geradora de conflito em um grupo de servidores do serviço público federal e a partir daí caso ocorram, buscar propostas que possam mitigar essas diferenças. Para atingir esses objetivos, optou-se por utilizar (como recurso metodológico) uma pesquisa exploratória de dados por meio de um estudo de caso. Os dados - coletados a partir de entrevistas semiestruturadas realizadas em determinada autarquia de ensino fundamental e médio do governo federal - foram tratados pela técnica de análise de conteúdo. Ao longo do desenvolvimento da pesquisa, identificou-se que as diferenças geracionais são perceptíveis pelos servidores no dia a dia e, eventualmente, elas provocam episódios de discordância na realização de algumas tarefas, comuns ou não. Por outro lado, diferentemente do fator geracional, identificou-se outro ponto de vista, que emerge como fonte geradora para o conflito: a rivalidade entre novos servidores (proponentes de nova realidade para serviço público), e servidores mais antigos (apegados a tradicionais costumes). / At the beginning of the new millennium a new generation of workers enters public service cadres: Generation Y. For the first time in history, three generations of servers working together in the federal executive branch: Baby Boomers, Generation X and generation Y, every generation has peculiar characteristics and attitudes that make them distinct, which sometimes leads to a climate of tension in the organizational environment. This work aims to identify whether and how the features and differences of generational attitudes are relevant as a source of generating conflict in a group of servers in the federal public service and, if they occur, get proposals that can mitigate these differences. To achieve these goals, we decided to use (such as methodological feature) an exploratory research of data through a case study. Collected data from semi-structured interviews carried out in a given municipality of elementary and secondary education in the federal Government-were treated by the technique of content analysis. Throughout the development of the survey, it was identified that generational differences are noticeable by the servers on a daily basis and, eventually, they cause episodes of disagreement in the execution of some tasks, common or not. On the other hand, unlike the generational factor, has another point of view, that emerges as a source for generating the conflict: the rivalry between new servers (proponents of new reality for public service), and older servers (attached to traditional customs).

Our society increasingly relies on the Internet for common services like online banking, shopping, and socializing. Many of these services heavily depend on secure end-to-end transactions to transfer personal, financial, or other sensitive information. At the core of ensuring secure transactions are the TLS/SSL protocol and the ``trust'' relationships between all involved partners. In this thesis we passively monitor the HTTPS traffic between a campus network and the Internet, and characterize the certificate usage and trust relationships in this complex landscape. By comparing our observations against known vulnerabilities and problems, we provide an overview of the actual security that typical Internet users (such as the people on campus) experience. Our measurements cover both mobile and stationary users, consider the involved trust relationships, and provide insights into how the HTTPS protocol is used and the weaknesses observed in practice.

This thesis investigates TCP connection management mechanisms in order to understand the behaviour and improve the performance of Internet servers during overload conditions such as flash crowds. We study several alternatives for implementing TCP connection establishment, reviewing approaches taken by existing TCP stacks as well as proposing new mechanisms to improve server throughput and reduce client response times under overload. We implement some of these connection establishment mechanisms in the Linux TCP stack and evaluate their performance in a variety of environments. We also evaluate the cost of supporting half-closed connections at the server and assess the impact of an abortive release of connections by clients on the throughput of an overloaded server. Our evaluation demonstrates that connection establishment mechanisms that eliminate the TCP-level retransmission of connection attempts by clients increase server throughput by up to 40% and reduce client response times by two orders of magnitude. Connection termination mechanisms that preclude support for half-closed connections additionally improve server throughput by up to 18%.

This report presents a series of models that can be used to find weekly schedules for therapists who provide ongoing treatment to patients scattered around a geographical region. In all cases, the patients’ appointment times and visit days are known prior to the beginning of the planning horizon. Variations in the model include single vs. multiple home bases, homogeneous vs. heterogeneous therapists, lunch break requirements, and a nonlinear cost structure for mileage reimbursement and overtime. The single home base and homogeneous therapist cases proved to be easy to solve and so were not investigated. This left two cases of interest: the first includes only lunch breaks while the second adds overtime and mileage reimbursement. In all, 40 randomly generated data sets were solved that consisted of either 15 or 20 therapists and between roughly 300 and 540 visits over five days. For each instance, we were able to obtain the minimum cost of providing home healthcare services for both models using CPLEX 12.2. The results showed that CPU time increases more rapidly than total cost as the total number of visits grows. In general, data sets with therapists who have different starting and ending locations are more difficult to solve than those whose therapists have the same home base. / text