University of Sao Paulo

Displaying 1-16 of 16 results

  • White Papers // Jun 2012

    Performance Evaluation of Video-on-Demand in Virtualized Environments: The Client Perspective

    Virtualization is a key technology for data centres to implement infrastructure as a service as well as to achieve server consolidation and application colocation. Over the years performance of Virtual Machine (VM) monitors have improved. Thus, new services are being migrated to these environments. Latency sensitive applications however, are not...

    Provided By University of Sao Paulo

  • White Papers // May 2012

    Asymptotic Performance Analysis of Precoded BICM-MIMO Under Channel Estimation Errors

    In this paper, the asymptotic performance of a precoded Bit-Interleaved Coded Modulation with Multiple-Input Multiple-Output (BICM-MIMO) system in a block-fading environment is first evaluated. Specifically, the asymptotic pairwise error probability is derived for imperfect Channel State Information (CSI) and of the Minimum Mean Squared-Error (MMSE) detector. The analysis is then...

    Provided By University of Sao Paulo

  • White Papers // Dec 2011

    Optimizing Cloud Providers Revenues Via Energy Efficient Server Allocation

    Cloud providers, like Amazon, offer their data centers' computational and storage capacities for lease to paying customers. High electricity consumption, not only reflects on the data center's carbon footprint but also increases the costs of running the data center itself. The authors examine the problem of managing a server farm...

    Provided By University of Sao Paulo

  • White Papers // Jun 2011

    Digital Signature for Mobile Devices: A New Implementation and Evaluation

    This paper presents a new implementation and evaluation of digital signature for mobile devices. This digital signature system takes into account the device limitations and thus generates a functional digital signature. Its efficiency is described and justified along the paper. It also presents a case study that allows the evaluation...

    Provided By University of Sao Paulo

  • White Papers // Feb 2011

    Party Finance And Party Competition In Dominant Multi-Party Systems: The Case Of South Africa

    Since their second democratic elections many 'New democracies' have reinforced multi-party systems with a single dominant ruling party which leaves little political capacity for the opposition parties. In the majority of cases, the dominant party benefits from the status quo finance regime and has little incentive to introduce a public...

    Provided By University of Sao Paulo

  • White Papers // Jan 2011

    Analysis of Security and Performance Aspects in Service-Oriented Architectures

    This paper presents a study on the use of security standards in the context of service oriented architectures with the goal of testing which are more costly in terms of performance in building secure Web services. Security policies applied to web services are evaluated through application development, testing and performance...

    Provided By University of Sao Paulo

  • White Papers // Jan 2011

    Spider Cursor: A Simple Versatile Interaction Tool for Data Visualization and Exploration

    The authors present Spider Cursor, an exploration tool for geometric models that has proven useful in analyzing data coming from various sources. The Spider Cursor is simple to learn and use, and is useful to help extract various types of relationships present in the data. Additionally, it implements a dual...

    Provided By University of Sao Paulo

  • White Papers // Dec 2010

    Input Parameters Optimization in Swarm DS-CDMA Multiuser Detectors

    In this paper, the uplink Direct Sequence Code Division Multiple Access (DS-CDMA) MultiUser Detection problem (MUD) is studied into heuristic perspective, named Particle Swarm Optimization (PSO). Regarding different system improvements for future technologies, such as high-order modulation and diversity exploitation, a complete parameter optimization procedure for the PSO applied to...

    Provided By University of Sao Paulo

  • White Papers // Nov 2010

    Network Headers Optimization for Distributed Programming

    This paper investigates the possibility of network cost reduction for distributed programming applications and presents a proposal for networks, with level 2 connectivity of the TCP/IP architecture. This proposal reduces the network traffic by minimizing the overhead of packet headers. To prove this enhancement possibility, it is presented the network...

    Provided By University of Sao Paulo

  • White Papers // Oct 2010

    RDBMS as an Efficient Tool to Mine Cliques on Complex Networks

    Complex networks are intrinsically present in a wide range of applications. Real world networks have several unique properties, such as, sparsity, node degree distribution, which follow a power law and a large amount of triangles that further form larger cliques. Triangles and cluster coefficient, which are usually used to find...

    Provided By University of Sao Paulo

  • White Papers // Sep 2010

    Threat Modeling an Identity Management System for Mobile Internet

    The advent of Mobile Internet and Web 2.0 raised the need for identity-oriented and user-centric services. In recent years, many Identity Management Systems (IdMS) have been developed to allow users to safely control and reuse their identity attributes. Service providers and users rely on the trust that the mechanisms provided...

    Provided By University of Sao Paulo

  • White Papers // Jun 2010

    FMI-SiR: A Flexible and Efficient Module for Similarity Searching on Oracle Database

    The volume of complex data (images, videos, audio, time series, DNA sequences, and others) has been growing at a very fast pace. Although they are not naturally handled by DataBase Management Systems (DBMSs), it is necessary to store them in databases. Complex data are well-suited to be queried by similarity,...

    Provided By University of Sao Paulo

  • White Papers // Feb 2010

    DBM-Tree: A Dynamic Metric Access Method Sensitive to Local Density Data

    Metric Access Methods (MAM) are widely employed to speed up the evaluation of similarity queries, such as range and k-nearest neighbor queries. Most of the currently MAM available today achieve reasonable good performance of query evaluation through minimizing the number of disk accesses required to evaluate a query. The classical...

    Provided By University of Sao Paulo

  • White Papers // Oct 2009

    Performance of Orthogonal Wireless Relay Networks with Multiple SNR-Thresholds and Multiple Hard-Decision Detections

    In this paper, the authors investigate the diversity performance of wireless relay networks with multiple parallel relays communicating with the destination over orthogonal channels. The networks under consideration employ two Signal-to-Noise Ratio (SNR) thresholds and multiple Hard-Decision Detections (HDDs) at the destination. One SNR threshold is used to select transmitting...

    Provided By University of Sao Paulo

  • White Papers // Sep 2009

    Mobility in IP Networks: From Link Layer to Application Layer Protocols and Architectures

    With the popularization of the Internet and mobile devices, like notebooks and PDAs (Personal Digital Assistants), the concept of portability started to become popular, in the sense that the user could take their device anywhere and start a new connection to the Internet. In the Internet, a node is identified...

    Provided By University of Sao Paulo

  • White Papers // Jun 2009

    A User-Centric Authentication and Privacy Control Mechanism for User Model Interoperability in Social Networking Sites

    In this paper, the authors present a new authentication and privacy control mechanism for personalized mashups of social networking sites. Current authentication and privacy control mechanisms lack flexibility and transparency. This paper can make the user model interoperation process for mashups more transparent to users. Users can have a clear...

    Provided By University of Sao Paulo

  • White Papers // Jun 2012

    Performance Evaluation of Video-on-Demand in Virtualized Environments: The Client Perspective

    Virtualization is a key technology for data centres to implement infrastructure as a service as well as to achieve server consolidation and application colocation. Over the years performance of Virtual Machine (VM) monitors have improved. Thus, new services are being migrated to these environments. Latency sensitive applications however, are not...

    Provided By University of Sao Paulo

  • White Papers // Jan 2011

    Analysis of Security and Performance Aspects in Service-Oriented Architectures

    This paper presents a study on the use of security standards in the context of service oriented architectures with the goal of testing which are more costly in terms of performance in building secure Web services. Security policies applied to web services are evaluated through application development, testing and performance...

    Provided By University of Sao Paulo

  • White Papers // Dec 2010

    Input Parameters Optimization in Swarm DS-CDMA Multiuser Detectors

    In this paper, the uplink Direct Sequence Code Division Multiple Access (DS-CDMA) MultiUser Detection problem (MUD) is studied into heuristic perspective, named Particle Swarm Optimization (PSO). Regarding different system improvements for future technologies, such as high-order modulation and diversity exploitation, a complete parameter optimization procedure for the PSO applied to...

    Provided By University of Sao Paulo

  • White Papers // Jan 2011

    Spider Cursor: A Simple Versatile Interaction Tool for Data Visualization and Exploration

    The authors present Spider Cursor, an exploration tool for geometric models that has proven useful in analyzing data coming from various sources. The Spider Cursor is simple to learn and use, and is useful to help extract various types of relationships present in the data. Additionally, it implements a dual...

    Provided By University of Sao Paulo

  • White Papers // Nov 2010

    Network Headers Optimization for Distributed Programming

    This paper investigates the possibility of network cost reduction for distributed programming applications and presents a proposal for networks, with level 2 connectivity of the TCP/IP architecture. This proposal reduces the network traffic by minimizing the overhead of packet headers. To prove this enhancement possibility, it is presented the network...

    Provided By University of Sao Paulo

  • White Papers // Sep 2010

    Threat Modeling an Identity Management System for Mobile Internet

    The advent of Mobile Internet and Web 2.0 raised the need for identity-oriented and user-centric services. In recent years, many Identity Management Systems (IdMS) have been developed to allow users to safely control and reuse their identity attributes. Service providers and users rely on the trust that the mechanisms provided...

    Provided By University of Sao Paulo

  • White Papers // Feb 2011

    Party Finance And Party Competition In Dominant Multi-Party Systems: The Case Of South Africa

    Since their second democratic elections many 'New democracies' have reinforced multi-party systems with a single dominant ruling party which leaves little political capacity for the opposition parties. In the majority of cases, the dominant party benefits from the status quo finance regime and has little incentive to introduce a public...

    Provided By University of Sao Paulo

  • White Papers // Sep 2009

    Mobility in IP Networks: From Link Layer to Application Layer Protocols and Architectures

    With the popularization of the Internet and mobile devices, like notebooks and PDAs (Personal Digital Assistants), the concept of portability started to become popular, in the sense that the user could take their device anywhere and start a new connection to the Internet. In the Internet, a node is identified...

    Provided By University of Sao Paulo

  • White Papers // Oct 2010

    RDBMS as an Efficient Tool to Mine Cliques on Complex Networks

    Complex networks are intrinsically present in a wide range of applications. Real world networks have several unique properties, such as, sparsity, node degree distribution, which follow a power law and a large amount of triangles that further form larger cliques. Triangles and cluster coefficient, which are usually used to find...

    Provided By University of Sao Paulo

  • White Papers // Jun 2010

    FMI-SiR: A Flexible and Efficient Module for Similarity Searching on Oracle Database

    The volume of complex data (images, videos, audio, time series, DNA sequences, and others) has been growing at a very fast pace. Although they are not naturally handled by DataBase Management Systems (DBMSs), it is necessary to store them in databases. Complex data are well-suited to be queried by similarity,...

    Provided By University of Sao Paulo

  • White Papers // Feb 2010

    DBM-Tree: A Dynamic Metric Access Method Sensitive to Local Density Data

    Metric Access Methods (MAM) are widely employed to speed up the evaluation of similarity queries, such as range and k-nearest neighbor queries. Most of the currently MAM available today achieve reasonable good performance of query evaluation through minimizing the number of disk accesses required to evaluate a query. The classical...

    Provided By University of Sao Paulo

  • White Papers // Jun 2011

    Digital Signature for Mobile Devices: A New Implementation and Evaluation

    This paper presents a new implementation and evaluation of digital signature for mobile devices. This digital signature system takes into account the device limitations and thus generates a functional digital signature. Its efficiency is described and justified along the paper. It also presents a case study that allows the evaluation...

    Provided By University of Sao Paulo

  • White Papers // May 2012

    Asymptotic Performance Analysis of Precoded BICM-MIMO Under Channel Estimation Errors

    In this paper, the asymptotic performance of a precoded Bit-Interleaved Coded Modulation with Multiple-Input Multiple-Output (BICM-MIMO) system in a block-fading environment is first evaluated. Specifically, the asymptotic pairwise error probability is derived for imperfect Channel State Information (CSI) and of the Minimum Mean Squared-Error (MMSE) detector. The analysis is then...

    Provided By University of Sao Paulo

  • White Papers // Oct 2009

    Performance of Orthogonal Wireless Relay Networks with Multiple SNR-Thresholds and Multiple Hard-Decision Detections

    In this paper, the authors investigate the diversity performance of wireless relay networks with multiple parallel relays communicating with the destination over orthogonal channels. The networks under consideration employ two Signal-to-Noise Ratio (SNR) thresholds and multiple Hard-Decision Detections (HDDs) at the destination. One SNR threshold is used to select transmitting...

    Provided By University of Sao Paulo

  • White Papers // Dec 2011

    Optimizing Cloud Providers Revenues Via Energy Efficient Server Allocation

    Cloud providers, like Amazon, offer their data centers' computational and storage capacities for lease to paying customers. High electricity consumption, not only reflects on the data center's carbon footprint but also increases the costs of running the data center itself. The authors examine the problem of managing a server farm...

    Provided By University of Sao Paulo

  • White Papers // Jun 2009

    A User-Centric Authentication and Privacy Control Mechanism for User Model Interoperability in Social Networking Sites

    In this paper, the authors present a new authentication and privacy control mechanism for personalized mashups of social networking sites. Current authentication and privacy control mechanisms lack flexibility and transparency. This paper can make the user model interoperation process for mashups more transparent to users. Users can have a clear...

    Provided By University of Sao Paulo