University of Lugano

Displaying 1-29 of 29 results

  • White Papers // Apr 2012

    A Framework for Realistic Simulation of Networked Multi-Robot Systems

    Networked robotics is an area that integrates multi-robot and network technology. The characteristics and the reliability of the communication environment play a fundamental role shaping and affecting behavior and performance of a mobile multi-robot system. In this context, two basic questions arise: how much the overall performance is affected and...

    Provided By University of Lugano

  • White Papers // Mar 2012

    Fully Decentralized Estimation of Some Global Properties of a Network

    It is often beneficial to architect networks and overlays as fully decentralized systems, in the sense that any computation (e.g., routing or search) would only use local information, and no single node would have a complete view or control over the whole network. Yet sometimes it also important to compute...

    Provided By University of Lugano

  • White Papers // Nov 2011

    Convergence Results for Vehicle Routing Problems With Stochastic Demands

    In this paper, the authors investigate two variants of the Stochastic Vehicle Routing Problem: The Vehicle Routing Problem with Stochastic Demands and the Vehicle Routing Problem with Stochastic Demands and Customers. They show that under some moderate conditions there is an asymptotic equivalence between the Vehicle Routing Problem with Stochastic...

    Provided By University of Lugano

  • White Papers // Oct 2011

    The Complexity of Data Aggregation in Directed Networks

    Consider a wireless network comprising two base stations, transmitting at high power, and an unknown number of client devices which communicate only with the base stations. The base stations are received at all devices, and each client device is received by at least one base station. However, due to power...

    Provided By University of Lugano

  • White Papers // Sep 2011

    Byzantine Fault-Tolerance With Commutative Commands

    State machine replication is a popular approach to increasing the availability of computer services. While it has been largely studied in the presence of crash-stop failures and malicious failures, all existing state machine replication protocols that provide byzantine fault-tolerance implement some variant of atomic broadcast. In this context, this paper...

    Provided By University of Lugano

  • White Papers // Jun 2011

    Probabilistic FIFO Ordering in Publish/Subscribe Networks

    In a best-effort publish/subscribe network, publications may be delivered out of order (e.g., violating FIFO order). The authors contend that the primary cause of such ordering violations is the parallel matching and forwarding process employed by brokers to achieve high throughput. In this paper, they present an end-to-end method to...

    Provided By University of Lugano

  • White Papers // Jun 2011

    Belisarius: BFT Storage With Confidentiality

    Traditional approaches to byzantine fault-tolerance have mostly avoided the problem of confidentiality. Current confidentiality-aware solutions rely on a heavy infrastructure investment or depend on complex key management schemes. The framework presented in this paper relies on a novel approach that combines byzantine fault-tolerance, secure storage and verifiable secret sharing to...

    Provided By University of Lugano

  • White Papers // Apr 2011

    Scalable Byzantine Fault-Tolerant Storage

    Byzantine fault-tolerance is a fundamental requirement for many contemporary services. Shorter development cycles, bigger server exposure to attacks, and an inherently hostile network have demonstrated the weaknesses of replication mechanisms designed for benign failures. Unfortunately, Byzantine Fault-Tolerant (BFT) services usually have increased latency, when compared to simple client-server interactions, and...

    Provided By University of Lugano

  • White Papers // Apr 2011

    High Performance State-Machine Replication

    State-machine replication is a well-established approach to fault tolerance. The idea is to replicate a service on multiple servers so that it remains available despite the failure of one or more servers. From a performance perspective, state-machine replication has two limitations. First, it introduces some overhead in service response time,...

    Provided By University of Lugano

  • White Papers // Mar 2011

    Handwritten Digit Recognition With a Committee of Deep Neural Nets on GPUs

    The competitive MNIST handwritten digit recognition benchmark has a long history of broken records since 1998. The most recent substantial improvement by others dates back 7 years (error rate 0.4%). Recently the authors were able to significantly improve this result, using graphics cards to greatly speed up training of simple...

    Provided By University of Lugano

  • White Papers // Jan 2011

    Byzantine Fault-Tolerant Deferred Update Replication

    Replication is a well-established approach to increasing database availability. Many database replication protocols have been proposed for the crash-stop failure model, in which servers fail silently. Fewer database replication protocols have been proposed for the byzantine failure model, in which servers may fail arbitrarily. This paper considers deferred update replication,...

    Provided By University of Lugano

  • White Papers // Jan 2011

    High-Performance Neural Networks for Visual Object Classification

    The authors present a fast, fully parameterizable GPU implementation of Convolutional Neural Network variants. The feature extractors are neither carefully designed nor pre-wired, but rather learned in a supervised way. The deep hierarchical architectures achieve the best published results on benchmarks for object classification (NORB, CIFAR10) and handwritten digit recognition...

    Provided By University of Lugano

  • White Papers // Nov 2010

    Froms: A Failure Tolerant and Mobility Enabled Multicast Routing Paradigm With Reinforcement Learning for WSNs

    A growing class of Wireless Sensor Network (WSN) applications require the use of sensed data inside the network at multiple, possibly mobile base stations. Standard WSN routing techniques that move data from multiple sources to a single, fixed base station are not applicable, motivating new solutions that efficiently achieve multicast...

    Provided By University of Lugano

  • White Papers // Jun 2010

    Qos and Security in Energy-Harvesting Wireless Sensor Networks

    Wireless sensor networks are composed of small nodes that might be used for a variety of purposes. Nodes communicate together through a wireless connection that might be subject to different attacks when the network is placed in hostile environments. Furthermore, the nodes are usually equipped with very small batteries providing...

    Provided By University of Lugano

  • White Papers // Mar 2010

    Multicoordinated Agreement for Groups of Agents

    Agents in agreement protocols play well distinct roles. Proposers propose values to the acceptors, which will accept proposals and inform the learners so, they detect that an agreement has been reached. A fourth role is that of the coordinator, who filters the proposals from proposers to acceptors. While proposers, learners,...

    Provided By University of Lugano

  • White Papers // Nov 2009

    Distributed Computation in Dynamic Networks : Technical Report

    In this paper, the authors investigate distributed computation in dynamic networks in which the network topology changes from round to round. They consider a worst-case model in which the communication links for each round are chosen by an adversary, and nodes do not know who their neighbors for the current...

    Provided By University of Lugano

  • White Papers // Oct 2009

    Fast, Flexible, and Highly Resilient Genuine FIFO and Causal Multicast Algorithms

    Developing dependable distributed applications is not easy. The complexity stems from the asynchrony and unreliability of typical distributed systems: processes execute at different speeds and may abruptly stop executing their code (i.e., crash). Moreover, messages may be arbitrarily delayed, received out-of-order, and even lost, if the sender or receiver is...

    Provided By University of Lugano

  • White Papers // Aug 2009

    Automated Performance Maintenance for Service Compositions

    Web service compositions, usually defined as BPEL processes, need to adapt to changes in their constituent web services, in order to maintain functionality and performance. Therefore, BPEL processes must be able to detect web service failure and performance degradation resulting in the violation of service-level agreements. Automated diagnosis and repair...

    Provided By University of Lugano

  • White Papers // Jun 2009

    When Uncertainty Blows In The Orchard: Comovement And Volatility Risk Premia

    Writers of index options earn high returns due to a significant and high volatility risk premium, but writers of options in single-stock markets earn lower returns. Using an incomplete information economy, the authors develop a structural model with multiple assets where agents have heterogeneous beliefs about the growth of firms'...

    Provided By University of Lugano

  • White Papers // May 2009

    Streamline: An Architecture for Overlay Multicast

    The authors propose Streamline, a two-layered architecture designed for media streaming in overlay networks. The first layer is a generic, customizable and lightweight protocol which is able to construct and maintain different types of meshes, exhibiting different properties. They discuss two types of overlay networks and explain how the first...

    Provided By University of Lugano

  • White Papers // Mar 2009

    An Environment for Synchronous Software Development

    Collaboration is essential for the development of complex software systems. When a team of developers is geographically distributed, collaboration aspects - such as awareness, communication and synchronization - are compromised by physical distance. The authors present an approach, named synchronous development, to reduce the negative distance effects on collaboration. They...

    Provided By University of Lugano

  • White Papers // Feb 2009

    Minimum Power Multicasting in Wireless Networks Under Probabilistic Node Failures

    In this paper, the authors deal with a new probabilistic extension of the Minimum Power Multi-cast (MPM) problem for wireless networks. The deterministic MPM problem consists in assigning transmission powers to the nodes, so that a multihop connection can be established between a source and a given set of destination...

    Provided By University of Lugano

  • White Papers // Feb 2009

    REMAN: A Pro-Active Reputation Management Infrastructure for Composite Web Services

    Web services are the de-facto standard for the development of distributed applications executing in open environments. Web services are usually composed by means of languages like BPEL to provide added-value services. Composite services, typically built from third-party services, have to adapt to the open, dynamically changing environment where remote services...

    Provided By University of Lugano

  • White Papers // Feb 2009

    Visual Exploration of Large-Scale Evolving Software

    The comprehensive understanding of today's software systems is a daunting activity, because of the sheer size and complexity that such systems exhibit. Moreover, software systems evolve, which dramatically increases the amount of data one needs to analyze in order to gain insights into such systems. Indeed, software complexity is recognized...

    Provided By University of Lugano

  • White Papers // Nov 2008

    Pension Benefit Insurance And Pension Plan Portfolio Choice

    Pension benefit guarantee policies have been introduced in several countries to protect private pension plan members from the loss of income that would occur if a plan was underfunded when the sponsoring firm terminates a plan. Most of these public insurance schemes face financial difficulty and consequently policy reforms are...

    Provided By University of Lugano

  • White Papers // Oct 2008

    Exploiting Data Semantics to Discover, Extract, and Model Web Sources

    The authors describe DEIMOS, a system that automatically discovers and models new sources of information. The system exploits four core technologies developed by their group that makes an end-to-end solution to this problem possible. First, given an example source, DEIMOS finds other similar sources online. Second, it invokes and extracts...

    Provided By University of Lugano

  • White Papers // Sep 2008

    Solving Atomic Multicast When Groups Crash

    In this paper, the authors study the atomic multicast problem, a fundamental abstraction for building fault-tolerant systems. In their model, processes are divided into non-empty and disjoint groups. Multicast messages may be addressed to any subset of groups, each message possibly being multicast to a different subset. Several papers previously...

    Provided By University of Lugano

  • White Papers // Aug 2008

    Correctness Criteria for Database Replication: Theoretical and Practical Aspects

    In this paper, the authors investigate correctness criteria for replicated databases from the client's perspective and present their uniform characterization. They further study the effects of different consistency degrees in the context of three middleware-based replication protocols: primary-backup, optimistic update-everywhere and BaseCON, a simple yet fault-tolerant middleware-based replication protocol that...

    Provided By University of Lugano

  • White Papers // Jan 2006

    Evaluating the Effectiveness of Image-Based Password Design Paradigms Using a Newly Developed Metric

    The authors discuss the usability versus security tradeoff in authentication systems and the reasons why the conventional text based password is still the most commonly used method of authentication even though it is inherently weak in many ways. After carrying out taxonomy of relevant issues they develop a metric that...

    Provided By University of Lugano

  • White Papers // Nov 2008

    Pension Benefit Insurance And Pension Plan Portfolio Choice

    Pension benefit guarantee policies have been introduced in several countries to protect private pension plan members from the loss of income that would occur if a plan was underfunded when the sponsoring firm terminates a plan. Most of these public insurance schemes face financial difficulty and consequently policy reforms are...

    Provided By University of Lugano

  • White Papers // Jan 2011

    High-Performance Neural Networks for Visual Object Classification

    The authors present a fast, fully parameterizable GPU implementation of Convolutional Neural Network variants. The feature extractors are neither carefully designed nor pre-wired, but rather learned in a supervised way. The deep hierarchical architectures achieve the best published results on benchmarks for object classification (NORB, CIFAR10) and handwritten digit recognition...

    Provided By University of Lugano

  • White Papers // Mar 2011

    Handwritten Digit Recognition With a Committee of Deep Neural Nets on GPUs

    The competitive MNIST handwritten digit recognition benchmark has a long history of broken records since 1998. The most recent substantial improvement by others dates back 7 years (error rate 0.4%). Recently the authors were able to significantly improve this result, using graphics cards to greatly speed up training of simple...

    Provided By University of Lugano

  • White Papers // Oct 2008

    Exploiting Data Semantics to Discover, Extract, and Model Web Sources

    The authors describe DEIMOS, a system that automatically discovers and models new sources of information. The system exploits four core technologies developed by their group that makes an end-to-end solution to this problem possible. First, given an example source, DEIMOS finds other similar sources online. Second, it invokes and extracts...

    Provided By University of Lugano

  • White Papers // Mar 2009

    An Environment for Synchronous Software Development

    Collaboration is essential for the development of complex software systems. When a team of developers is geographically distributed, collaboration aspects - such as awareness, communication and synchronization - are compromised by physical distance. The authors present an approach, named synchronous development, to reduce the negative distance effects on collaboration. They...

    Provided By University of Lugano

  • White Papers // Feb 2009

    REMAN: A Pro-Active Reputation Management Infrastructure for Composite Web Services

    Web services are the de-facto standard for the development of distributed applications executing in open environments. Web services are usually composed by means of languages like BPEL to provide added-value services. Composite services, typically built from third-party services, have to adapt to the open, dynamically changing environment where remote services...

    Provided By University of Lugano

  • White Papers // Feb 2009

    Visual Exploration of Large-Scale Evolving Software

    The comprehensive understanding of today's software systems is a daunting activity, because of the sheer size and complexity that such systems exhibit. Moreover, software systems evolve, which dramatically increases the amount of data one needs to analyze in order to gain insights into such systems. Indeed, software complexity is recognized...

    Provided By University of Lugano

  • White Papers // Jun 2009

    When Uncertainty Blows In The Orchard: Comovement And Volatility Risk Premia

    Writers of index options earn high returns due to a significant and high volatility risk premium, but writers of options in single-stock markets earn lower returns. Using an incomplete information economy, the authors develop a structural model with multiple assets where agents have heterogeneous beliefs about the growth of firms'...

    Provided By University of Lugano

  • White Papers // Jun 2010

    Qos and Security in Energy-Harvesting Wireless Sensor Networks

    Wireless sensor networks are composed of small nodes that might be used for a variety of purposes. Nodes communicate together through a wireless connection that might be subject to different attacks when the network is placed in hostile environments. Furthermore, the nodes are usually equipped with very small batteries providing...

    Provided By University of Lugano

  • White Papers // Nov 2010

    Froms: A Failure Tolerant and Mobility Enabled Multicast Routing Paradigm With Reinforcement Learning for WSNs

    A growing class of Wireless Sensor Network (WSN) applications require the use of sensed data inside the network at multiple, possibly mobile base stations. Standard WSN routing techniques that move data from multiple sources to a single, fixed base station are not applicable, motivating new solutions that efficiently achieve multicast...

    Provided By University of Lugano

  • White Papers // Aug 2009

    Automated Performance Maintenance for Service Compositions

    Web service compositions, usually defined as BPEL processes, need to adapt to changes in their constituent web services, in order to maintain functionality and performance. Therefore, BPEL processes must be able to detect web service failure and performance degradation resulting in the violation of service-level agreements. Automated diagnosis and repair...

    Provided By University of Lugano

  • White Papers // Sep 2011

    Byzantine Fault-Tolerance With Commutative Commands

    State machine replication is a popular approach to increasing the availability of computer services. While it has been largely studied in the presence of crash-stop failures and malicious failures, all existing state machine replication protocols that provide byzantine fault-tolerance implement some variant of atomic broadcast. In this context, this paper...

    Provided By University of Lugano

  • White Papers // Jun 2011

    Belisarius: BFT Storage With Confidentiality

    Traditional approaches to byzantine fault-tolerance have mostly avoided the problem of confidentiality. Current confidentiality-aware solutions rely on a heavy infrastructure investment or depend on complex key management schemes. The framework presented in this paper relies on a novel approach that combines byzantine fault-tolerance, secure storage and verifiable secret sharing to...

    Provided By University of Lugano

  • White Papers // Jun 2011

    Probabilistic FIFO Ordering in Publish/Subscribe Networks

    In a best-effort publish/subscribe network, publications may be delivered out of order (e.g., violating FIFO order). The authors contend that the primary cause of such ordering violations is the parallel matching and forwarding process employed by brokers to achieve high throughput. In this paper, they present an end-to-end method to...

    Provided By University of Lugano

  • White Papers // Apr 2011

    Scalable Byzantine Fault-Tolerant Storage

    Byzantine fault-tolerance is a fundamental requirement for many contemporary services. Shorter development cycles, bigger server exposure to attacks, and an inherently hostile network have demonstrated the weaknesses of replication mechanisms designed for benign failures. Unfortunately, Byzantine Fault-Tolerant (BFT) services usually have increased latency, when compared to simple client-server interactions, and...

    Provided By University of Lugano

  • White Papers // Apr 2011

    High Performance State-Machine Replication

    State-machine replication is a well-established approach to fault tolerance. The idea is to replicate a service on multiple servers so that it remains available despite the failure of one or more servers. From a performance perspective, state-machine replication has two limitations. First, it introduces some overhead in service response time,...

    Provided By University of Lugano

  • White Papers // Jan 2011

    Byzantine Fault-Tolerant Deferred Update Replication

    Replication is a well-established approach to increasing database availability. Many database replication protocols have been proposed for the crash-stop failure model, in which servers fail silently. Fewer database replication protocols have been proposed for the byzantine failure model, in which servers may fail arbitrarily. This paper considers deferred update replication,...

    Provided By University of Lugano

  • White Papers // Mar 2010

    Multicoordinated Agreement for Groups of Agents

    Agents in agreement protocols play well distinct roles. Proposers propose values to the acceptors, which will accept proposals and inform the learners so, they detect that an agreement has been reached. A fourth role is that of the coordinator, who filters the proposals from proposers to acceptors. While proposers, learners,...

    Provided By University of Lugano

  • White Papers // Oct 2009

    Fast, Flexible, and Highly Resilient Genuine FIFO and Causal Multicast Algorithms

    Developing dependable distributed applications is not easy. The complexity stems from the asynchrony and unreliability of typical distributed systems: processes execute at different speeds and may abruptly stop executing their code (i.e., crash). Moreover, messages may be arbitrarily delayed, received out-of-order, and even lost, if the sender or receiver is...

    Provided By University of Lugano

  • White Papers // May 2009

    Streamline: An Architecture for Overlay Multicast

    The authors propose Streamline, a two-layered architecture designed for media streaming in overlay networks. The first layer is a generic, customizable and lightweight protocol which is able to construct and maintain different types of meshes, exhibiting different properties. They discuss two types of overlay networks and explain how the first...

    Provided By University of Lugano

  • White Papers // Sep 2008

    Solving Atomic Multicast When Groups Crash

    In this paper, the authors study the atomic multicast problem, a fundamental abstraction for building fault-tolerant systems. In their model, processes are divided into non-empty and disjoint groups. Multicast messages may be addressed to any subset of groups, each message possibly being multicast to a different subset. Several papers previously...

    Provided By University of Lugano

  • White Papers // Aug 2008

    Correctness Criteria for Database Replication: Theoretical and Practical Aspects

    In this paper, the authors investigate correctness criteria for replicated databases from the client's perspective and present their uniform characterization. They further study the effects of different consistency degrees in the context of three middleware-based replication protocols: primary-backup, optimistic update-everywhere and BaseCON, a simple yet fault-tolerant middleware-based replication protocol that...

    Provided By University of Lugano

  • White Papers // Apr 2012

    A Framework for Realistic Simulation of Networked Multi-Robot Systems

    Networked robotics is an area that integrates multi-robot and network technology. The characteristics and the reliability of the communication environment play a fundamental role shaping and affecting behavior and performance of a mobile multi-robot system. In this context, two basic questions arise: how much the overall performance is affected and...

    Provided By University of Lugano

  • White Papers // Nov 2011

    Convergence Results for Vehicle Routing Problems With Stochastic Demands

    In this paper, the authors investigate two variants of the Stochastic Vehicle Routing Problem: The Vehicle Routing Problem with Stochastic Demands and the Vehicle Routing Problem with Stochastic Demands and Customers. They show that under some moderate conditions there is an asymptotic equivalence between the Vehicle Routing Problem with Stochastic...

    Provided By University of Lugano

  • White Papers // Feb 2009

    Minimum Power Multicasting in Wireless Networks Under Probabilistic Node Failures

    In this paper, the authors deal with a new probabilistic extension of the Minimum Power Multi-cast (MPM) problem for wireless networks. The deterministic MPM problem consists in assigning transmission powers to the nodes, so that a multihop connection can be established between a source and a given set of destination...

    Provided By University of Lugano

  • White Papers // Mar 2012

    Fully Decentralized Estimation of Some Global Properties of a Network

    It is often beneficial to architect networks and overlays as fully decentralized systems, in the sense that any computation (e.g., routing or search) would only use local information, and no single node would have a complete view or control over the whole network. Yet sometimes it also important to compute...

    Provided By University of Lugano

  • White Papers // Oct 2011

    The Complexity of Data Aggregation in Directed Networks

    Consider a wireless network comprising two base stations, transmitting at high power, and an unknown number of client devices which communicate only with the base stations. The base stations are received at all devices, and each client device is received by at least one base station. However, due to power...

    Provided By University of Lugano

  • White Papers // Nov 2009

    Distributed Computation in Dynamic Networks : Technical Report

    In this paper, the authors investigate distributed computation in dynamic networks in which the network topology changes from round to round. They consider a worst-case model in which the communication links for each round are chosen by an adversary, and nodes do not know who their neighbors for the current...

    Provided By University of Lugano

  • White Papers // Jan 2006

    Evaluating the Effectiveness of Image-Based Password Design Paradigms Using a Newly Developed Metric

    The authors discuss the usability versus security tradeoff in authentication systems and the reasons why the conventional text based password is still the most commonly used method of authentication even though it is inherently weak in many ways. After carrying out taxonomy of relevant issues they develop a metric that...

    Provided By University of Lugano