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‣ Codificação progressiva sem perdas utilizando a tecnica de codificação aritmetica baseada no padrão JBIG

Ahmed Mohamed Abushaala
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 07/04/2004 Português
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Neste trabalho, apresenta-se um tutorial sobre a técnica de Codificação Aritmética Binária Adaptativa (CABA), onde a CABA é a base principal do padrão JBIG ("Joint Bi-level Image Experts Group"). O esforço é dedicado para o estudo e a implementação de quatro sub-blocos que fazem parte do padrão JBIG: sub-bloco "Redutor de Resolução", sub-bloco "Predição Típica", sub-bloco "Template Modelo" e sub-bloco "Codificador Aritmético Adaptativo". O presente trabalho tem como objetivo o desenvolvimento de protótipo software de "Codec" de CABA para imagens de escala de cinzas e imagens coloridas, tendo-se em vista a codificação sem perdas. Realizou-se a simulação de uma nova proposta usando-se método progressivo do padrão JBIG com o objetivo de se representar a informação de imagem em planos de bits e camadas de resolução. Essa proposta consiste em se transferir o modo progressivo para o decodificador do JBIG ao invés de usá-lo no codificador que é o procedimento comum. Isso permitirá o ganho desejado na taxa de compressão. Os resultados numéricos são apresentados e analisados.; In this work, a tutorial about an Adaptive Binary Arithmetic Coding technique (ABAC) is presented, where the ABAC is the principal base of the JBIG standard ("Joint Bi-level Image Experts Group"). The main effort is dedicated to the study and the implementation of four sub-blocks of the JBIG standard namely: sub-block "Resolution Reduction"...

‣ Reforço da privacidade através do controlo da pegada digital

Macedo, Ricardo Joaquim Pereira de
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Dissertação de Mestrado
Publicado em //2013 Português
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Dissertação de mestrado em Engenharia Informática; Atualmente existe ainda uma relação assimétrica entre os utilizadores e os fornecedores de serviços disponibilizados pela internet. É prática comum, aquando da apresentação de um serviço, que o utilizador seja questionado sobre a aceitação, ou não, de um conjunto de políticas referentes ao uso de informação privada facultada ao fornecedor (por exemplo, a morada, o número de telefone, preferências, etc...). Geralmente os utilizadores aceitam a política com base na confiança que têm no fornecedor e/ou no contrato formal que lhes é apresentado. Os casos de violação de privacidade por parte de alguns fornecedores de serviços, vendendo ou facultando informação privada sobre os seus clientes a outros, são amplamente conhecidos e resultam em grande medida da falta de controlo que os utilizadores finais têm sobre a informação que entregam aos fornecedores. Este problema também tem grande impacto no ambiente empresarial. Quase toda a informação de uma organização é guardada em claro. Mesmo que esta seja guardada num local seguro, aqueles que conhecerem bem o sistema poderão ter indevidamente acesso a informação privada da organização. Além disto...

‣ Self-reported prevalence of endometriosis and its symptoms among Puerto Rican women

Flores, Idhaliz; Abreu, Silkha; Abac, Sonia; Fourquet, Jessica; Laboy, Joaquin; Ríos-Bedoya, Carlos
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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‣ Patients’ report on how endometriosis affects health, work, and daily life

Fourquet, Jessica; Gao, Xin; Zavala, Diego; Orengo, Juan C.; Abac, Sonia; Ruiz, Abigail; Laboy, Joaquín; Flores, Idhaliz
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/05/2010 Português
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The objective of this study was to assess the burden of endometriosis by obtaining Patient Reported Outcome (PRO) data describing the experience of living with this disease. Survey data from one hundred and seven women with self-reported, surgically diagnosed endometriosis showed that living with this disease may be characterized by physical limitations that disrupt health, work and daily life.

‣ Beauty Is in the Eye of the Beholder: Proteins Can Recognize Binding Sites of Homologous Proteins in More than One Way

Martin, Juliette
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Português
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Understanding the mechanisms of protein–protein interaction is a fundamental problem with many practical applications. The fact that different proteins can bind similar partners suggests that convergently evolved binding interfaces are reused in different complexes. A set of protein complexes composed of non-homologous domains interacting with homologous partners at equivalent binding sites was collected in 2006, offering an opportunity to investigate this point. We considered 433 pairs of protein–protein complexes from the ABAC database (AB and AC binary protein complexes sharing a homologous partner A) and analyzed the extent of physico-chemical similarity at the atomic and residue level at the protein–protein interface. Homologous partners of the complexes were superimposed using Multiprot, and similar atoms at the interface were quantified using a five class grouping scheme and a distance cut-off. We found that the number of interfacial atoms with similar properties is systematically lower in the non-homologous proteins than in the homologous ones. We assessed the significance of the similarity by bootstrapping the atomic properties at the interfaces. We found that the similarity of binding sites is very significant between homologous proteins...

‣ Redetermination of Zn2Mo3O8

Cuny, Jerome; Gougeon, Patrick; Gall, Philippe
Fonte: International Union of Crystallography Publicador: International Union of Crystallography
Tipo: Artigo de Revista Científica
Publicado em 13/06/2009 Português
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The crystal structure of dizinc trimolybdenum(IV) octa­oxide, Zn2Mo3O8, has been redetermined from single-crystal X-ray data. The structure has been reported previously based on neutron powder diffraction data [Hibble et al. (1999 ▶). Acta Cryst. B55, 683-697] and single-crystal data [McCarroll et al. (1957 ▶). J. Am. Chem. Soc. 79, 5410–5414; Ansell & Katz (1966 ▶) Acta Cryst. 21, 482–485]. The results of the current redetermination show an improvement in the precision of the structural and geometric parameters with all atoms refined with anisotropic displacement parameters. The crystal structure consists of distorted hexa­gonal-close-packed oxygen layers with stacking sequence abac along [001] and is held together by alternating zinc and molybdenum layers. The Zn atoms occupy both tetra­hedral and octa­hedral inter­stices with a ratio of 1:1. The Mo atoms occupy octa­hedral sites and form strongly bonded triangular clusters involving three MoO6 octa­hedra that are each shared along two edges, forming a Mo3O13 unit. All atoms lie on special positions. The Zn atoms are in 2b Wyckoff positions with 3m. site symmetry, the Mo atoms are in 6c Wyckoff positions with . m. site symmetry and the O atoms are in 2a...

‣ SNPs in the Lysyl Oxidase-like Protein 4 (LOXL4) and Complement Component 3 (C3) genes are Associated with Increased Risk for Endometriosis and Endometriosis-Associated Infertility

Ruiz, Lynnette A.; Dutil, Julie; Ruiz, Abigail; Fourquet, Jessica; Abac, Sonia; Laboy, Joaquín; Flores, Idhaliz
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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This study was conducted to assess genetic associations to endometriosis in a Puerto Rican population. Significant differences in allelic frequencies and genotype distribution of genetic variants in LOXL4 and C3 were documented in patients with endometriosis-associated infertility vs controls, and in patients with endometriosis vs controls, respectively, and in women having the risk genotype at both SNPs, the estimated risk for endometriosis nearly doubled.

‣ An Action-Based Fine-Grained Access Control Mechanism for Structured Documents and Its Application

Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Português
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This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical.

‣ On phrase rhythm in jazz

Love, Stefan (1984 - )
Fonte: Universidade de Rochester Publicador: Universidade de Rochester
Tipo: Tese de Doutorado Formato: Dimensions:28 cm; Number of Pages:x, 260 leaves
Português
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Includes abstract and vita. --- Thesis (Ph.D.)--University of Rochester, 2011. --- Part 1. Theory. Introduction: What is jazz? What is phrase rhythm? ; Meter and grouping in jazz ; The analytical method -- Part 2. Applications. Introduction ; Thirty-two-bar schemes in AABA form ; Thirty-two-bar schemes in ABAC form ; The twelve-bar blues ; Metrically atypical schemes ; Some pedagodical and analytical extenses -- Appendix A. Glossary of terms and notations ; Appendix B. Complete transcriptions and analysis.; Phrase rhythm is the interaction of grouping structure and metrical structure. In jazz improvisation, these structures behave in ways that theories of phrase rhythm designed for classical music cannot accommodate. Specifically, jazz improvisation involves the superimposition of a highly flexible grouping structure on a pre-determined and predictable metrical-harmonic scheme. In this context, theories of phrase rhythm that depend on voiceleading or harmony neglect the subtleties of grouping structure.
In this dissertation, I present a new method for the analysis of jazz phrase rhythm. I classify each phrase based on its relationship to the metrical hierarchy, as manifested in two characteristics: 1) the pattern of metrical accents it overlaps (prosody)...

‣ Towards an APEC Food System

Anderson, K.
Fonte: New Zealand Ministry of Foreign Affairs and Trade; Wellington, New Zealand Publicador: New Zealand Ministry of Foreign Affairs and Trade; Wellington, New Zealand
Tipo: Livro
Publicado em //2000 Português
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What is an APEC Food System? Leaders of APEC's 21 member governments are committed to achieving free and open trade and investment and to better trade facilitation and greater economic and technical cooperation within the APEC region. Considerable progress has already been made towards those goals, but least so in the food sector. The latter needs to be addressed urgently, not only because of the wastefulness of current policies but also because the vast majority of the region's poor depend heavily on agriculture for their livelihood. With this in mind, the APEC Business Advisory Council (ABAC) proposed in September 1998 that APEC leaders take joint action to develop a so-called APEC Food System to boost the food sector's contribution to the prosperity of APEC's economies. While not doubting the region's capacity to continue to meet its aggregate food needs, the question raised by ABAC is whether demand could be met in a more efficient and environmentally responsible way, and in such a way that people feel more food-secure and the poor are better off.; http://papers.ssrn.com/sol3/papers.cfm?abstract_id=231233; Report prepared for New Zealand’s Ministry of Foreign Affairs and Trade, Wellington.

‣ The development of a vocabulary instruction model for content and language integrated learning for English language learners in Bangkok

McBain, Robert Alexander; Saint Joseph Bangna School ABAC University; Mhunpiew, Nathara; The Graduate School of Education, ABAC University
Fonte: Universidade La Sabana Publicador: Universidade La Sabana
Tipo: Artigo de Revista Científica
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This paper presents a research project on content vocabulary instruction with a focus on the development of a model to improve vocabulary learning in a content language integrated learning (CLIL) environment. The model was based on Cronbachs 1942 and Stahl and Fairbanks 1986 theories of vocabulary learning which emphasise a progressive approach starting at a basic level and then an intermediate level and which culminates to a  productive stage of specific vocabulary. The model also relates to the analysis of classroom discourse which highlights the importance of a student centered learning approach where emphasis is placed on encouraging students to progress more at their own pace and in their own time rather than the circumstances set by the teacher, in light of concerns over the amount of and frequent use of content vocabulary; while studying major theories in content area studies.

‣ Effectiveness of brief time-out with and without contingent delay: a comparative analysis.

Mace, F C; Page, T J; Ivancic, M T; O'Brien, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1986 Português
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We evaluated a commonly used component of brief time-out, in which release from time-out is delayed contingent on the occurrence of disruption. Data were collected for one normal and two mentally retarded children on time-out-producing behaviors (aggression and disruption) as well as delay-producing behaviors during time-out (loud vocalizations, out-of-chair, aggression, and disruption). The results of a combination ABAC reversal and multiple-baseline design indicated that, under the conditions used in this investigation, both delay and no delay variations were effective in reducing the frequency of the target behaviors. Implications for the use of time-out to reduce aberrant behaviors are discussed.

‣ Brain-computer interface: proposal of a shaping-based training

Silva-Sauer,Leandro da; Valero-Aguayo,Luis; Velasco-Álvarez,Francisco; Ron-Angevín,Ricardo; Sancha-Ros,Salvador
Fonte: SBEB - Sociedade Brasileira de Engenharia Biomédica Publicador: SBEB - Sociedade Brasileira de Engenharia Biomédica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 Português
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INTRODUCTION: Persons affected by certain motor disabilities such as amyotrophic lateral sclerosis can evolve with important motor and speech difficulties in communication. A BCI (Brain Computer Interface) is a system that allows interaction between the human brain and a computer, permitting the user to control a communication channel through his or her brain activity. It is based on the analysis and processing of electroencephalographic (EEG) signals to generate control commands. The present study focuses on the subjects' capability to improve the way they learn to control a BCI system. METHODS: Two training procedures were compared: standard and progressive shaping response. Six volunteers participated in a reversal single-subject ABAC design. RESULTS: The study showed that both procedures are equally effective in producing a differential responding in the EEG signals, with no significant differences between them. Nevertheless, there were significant differences when distinguishing two neuronal responses (relax state and hand-movement imagination). Also, in the analysis of individual signals, an adaptive process for the shaping process and a lower error rate in the idle response appeared. CONCLUSION: Both proposed training procedures...

‣ Mining Attribute-based Access Control Policies

Xu, Zhongyuan; Stoller, Scott D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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Attribute-based access control (ABAC) provides a high level of flexibility that promotes security and information sharing. ABAC policy mining algorithms have potential to significantly reduce the cost of migration to ABAC, by partially automating the development of an ABAC policy from an access control list (ACL) policy or role-based access control (RBAC) policy with accompanying attribute data. This paper presents an ABAC policy mining algorithm. To the best of our knowledge, it is the first ABAC policy mining algorithm. Our algorithm iterates over tuples in the given user-permission relation, uses selected tuples as seeds for constructing candidate rules, and attempts to generalize each candidate rule to cover additional tuples in the user-permission relation by replacing conjuncts in attribute expressions with constraints. Our algorithm attempts to improve the policy by merging and simplifying candidate rules, and then it selects the highest-quality candidate rules for inclusion in the generated policy.

‣ Automated Certification of Authorisation Policy Resistance

Griesmayer, Andreas; Morisset, Charles
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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Attribute-based Access Control (ABAC) extends traditional Access Control by considering an access request as a set of pairs attribute name-value, making it particularly useful in the context of open and distributed systems, where security relevant information can be collected from different sources. However, ABAC enables attribute hiding attacks, allowing an attacker to gain some access by withholding information. In this paper, we first introduce the notion of policy resistance to attribute hiding attacks. We then propose the tool ATRAP (Automatic Term Rewriting for Authorisation Policies), based on the recent formal ABAC language PTaCL, which first automatically searches for resistance counter-examples using Maude, and then automatically searches for an Isabelle proof of resistance. We illustrate our approach with two simple examples of policies and propose an evaluation of ATRAP performances.; Comment: 20 pages, 4 figures, version including proofs of the paper that will be presented at ESORICS 2013

‣ Mining Attribute-Based Access Control Policies from Logs

Xu, Zhongyuan; Stoller, Scott D.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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Attribute-based access control (ABAC) provides a high level of flexibility that promotes security and information sharing. ABAC policy mining algorithms have potential to significantly reduce the cost of migration to ABAC, by partially automating the development of an ABAC policy from information about the existing access-control policy and attribute data. This paper presents an algorithm for mining ABAC policies from operation logs and attribute data. To the best of our knowledge, it is the first algorithm for this problem.; Comment: arXiv admin note: substantial text overlap with arXiv:1306.2401

‣ Control d’accés al Routing Information Tree en un esquema de xarxes DTN actives

Pascual Clemente, Ramsés
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: info:eu-repo/semantics/bachelorThesis; Text Formato: application/pdf
Publicado em //2014 Português
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En aquest treball es modifica una variant del ja conegut sistema de control d'accés anomenat ABAC. Aquesta variant s'implementa dins d'una DTN activa, permetent així afegir un component de seguretat dins la xarxa. Al ser un tipus de xarxa que permet endarreriments de la transmissió, ABAC ha de ser adaptat per aquest cas, variant els mòduls interns del que es composa, evitant d'aquesta manera que hi hagi pèrdua de dades per falta de connectivitat. Al llarg de l'article es pot observar: l'entorn en que s'aplicarà aquest TFG; els petits canvis que es realitzaran, tant d'ABAC, que per aquest projecte els seus mòduls no estaran directament connectats, com dels components de la xarxa; petites variacions en el codi i l'agregació d'algunes comparacions per fer servir el filtre proposat; i finalment, la metodologia utilitzada per arribar a la solució proposada, juntament amb la conclusió extreta després de trobar una de les possibles respostes al problema.; In this work, a modification of the already well known access control system ABAC is presented. Implementing this variant inside an active DTN, allowing to add a security component into the network. As DTN allows transmission delays, ABAC had to be adapted in order to work correctly with this case. Changes its internal modules have been preventing leaks in case of connectivity losses. Along the present paper...

‣ Secure access control for health information sharing systems

Alshehri, Suhair; Raj, Rajendra
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Relatório
Português
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The 2009 Health Information Technology for Economic and Clinical Health Act (HITECH) encourages healthcare providers to share information to improve healthcare quality at reduced cost. Such information sharing, however, raises security and privacy concerns that require appropriate access control mechanisms to ensure Health Insurance Portability and Accountability Act (HIPAA) compliance. Current approaches such as Role-Based Access Control (RBAC) and its variants, and newer approaches such as Attribute-Based Access Control (ABAC) are inadequate. RBAC provides simple administration of access control and user permission review, but demands complex initial role engineering and makes access control inflexible. ABAC, on the other hand, simplifies initial setup but increases the complexity of managing privileges and user permissions. These limitations have motivated research into the development of newer access control models that use attributes and policies while preserving RBAC's strengths. The BiLayer Access Control (BLAC) model is a two-step method being proposed to integrate attributes with roles: an access request is checked against pseudoroles, i.e., the list of subject attributes (first layer), and then against rules within the policies (second layer) associated with the requested object. This paper motivates the BLAC approach...

‣ Insider threat mitigation and access control in healthcare systems

Alshehri, Suhair; Mishra, Sumita; Raj, Rajendra
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Relatório
Português
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Rapid and reliable information sharing of patient healthcare information has become critical for achieving better care with lower costs. However, such healthcare information sharing requires to be done securely with privacy guarantees, as required by law. Among its other requirements, the Health Insurance Portability and Accountability Act (HIPAA) requires the use of appropriate access control mechanisms to protect healthcare information. Despite these legal requirements, currently implemented access control models in the healthcare domain are typically inadequate as demonstrated by the large and increasing numbers of successful attacks on healthcare systems. In particular, current access control models do not provide sufficient protection for healthcare systems from attacks by insiders, i.e., authorized healthcare personnel. This paper examines how healthcare information can be protected from unauthorized or improper use, disclosure, alteration, and destruction by health- care providers. Using a holistic approach toward modeling access control, the authors construct a threat model for access control in healthcare systems. The constructed model is then used to assess the effectiveness of current access control mechanisms such as Role-Based Access Control (RBAC) and Attribute-Based Access Control (ABAC)...