Universidad Politecnica de Madrid

Displaying 1-40 of 54 results

  • White Papers // Jan 2014

    Edinet: An Execution Driven Interconnection Network Simulator for DSM Systems

    Interconnection network evaluation studies usually assume that the workload generated by actual applications can be modeled by synthetic workloads. Constant message generation rate (equal for all nodes), uniform distribution of message destinations (with or without locality) and fixed traffic patterns are frequently used. Evaluation studies on interconnection networks for distributed...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2013

    XtratuM Hypervisor Redesign for LEON4 Multicore Processor

    XtratuM is an open source hypervisor that uses para-virtualization techniques designed to comply with safety critical real-time requirements. Several projects aimed to de ne a reference architecture for space on-board systems have adopted XtratuM as a virtualization layer in order to enforce the strong spatial and temporal isolation between software...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Apr 2013

    A Model of Resource Management in Small Cells With Dynamic Traffic and Backhaul Constraints

    During the last years, the volume of data-traffic carried by mobile cellular networks has experienced a major growth and progress. The current networks' features are not enough to face this development paradigm and the novel concept of small cells has emerged to increase the network capacity. However, the deployment of...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Apr 2013

    Dynamic Spectrum Sharing in Cognitive Radio Networks Using Truthful Mechanisms and Virtual Currency

    In cognitive radio networks, there are scenarios where Secondary Users (SUs) utilize opportunistically the spectrum originally allocated to Primary Users (PUs). The spectrum resources available to SUs fluctuate over time due to PUs activity, SUs mobility and competition between SUs. In order to utilize these resources efficiently spectrum sharing techniques...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2013

    Integrating Wireless Sensor Nodes and Smartphones for Energy-Efficient Data Exchange in Smart Environments

    To effectively exploit the potential of smart environments, an energy-efficient data exchange between the smart environment infrastructure and its users is necessary. Usually, a major building block of smart environments is different sensors, which typically communicate making use of the IEEE 802.15.4 standard. Opposed to this, users in a smart...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2013

    Pre-Allocating Code Mappings for Energy-Efficient Data Encoding in Wireless Sensor Networks

    Energy is a scarce resource on battery-powered wireless sensor nodes, and wireless communication represents the major consumer of electric energy on most current platforms. Reducing the number and size of radio transmissions thus represents a viable approach to save energy and extend a node's operational time. In the domain of...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2012

    Approximate Analysis of Cognitive Radio Systems Using Time-Scale Separation and Its Accuracy

    The authors model a cognitive radio system as a Quasi-Birth-Death (QBD) process and determine its performance parameters. They also model the system at the quasi-stationary limiting regime. They show that this regime defines the asymptotic system behavior. The performance parameters of interest at this regime are independent of the service...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2012

    Electric Appliance Classification Based on Distributed High Resolution Current Sensing

    Today's solutions to inform residents about their electricity consumption are mostly confined to displaying aggregate readings collected at meter level. A reliable identification of appliances that require disproportionate amounts of energy for their operation is generally unsupported by these systems, or at least requires significant manual configuration efforts. The authors...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2012

    Distributed Data Filtering in Logistics Wireless Sensor Networks Based on Transmission Relevance

    Energy-efficient operation is mandatory in wireless sensor networks due to the limited energy budget of sensor nodes. Considering the potential application of wireless sensor networks in logistics, cost efficiency is another major requirement due to high cost pressure. To save on data transmissions within such sensor deployments, which account for...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2012

    Privacy Bubbles: User-Centered Privacy Control for Mobile Content Sharing Applications

    A continually increasing number of pictures and videos are shared in online social networks. Current sharing platforms however only offer limited options to de ne who has access to the content. Users may either share it with individuals or groups from their social graph, or make it available to the...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2012

    Femtocell Operator Entry Decision With Spectrum Bargaining and Service Competition

    This paper analyzes the effect of the entry of a femtocell operator into a mobile communications market where a macrocell operator exists. The analysis is conducted using a game theory-based model, specifically a three - level multi leader - follower game, where different solution concepts are applied: Shapley value, Nash...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2012

    The Hitchhiker's Guide to Choosing the Compression Algorithm for Your Smart Meter Data

    Smart meters are increasingly penetrating the market, resulting in enormous data volumes to be communicated. In many cases, embedded devices collect the metering data and transmit them wirelessly to achieve cheap and facile deployment. Bandwidth is yet scarce and transmission occupies the spectrum. Smart meter data should hence be compressed...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2012

    CBFR: Bloom Filter Routing With Gradual Forgetting for Tree-Structured Wireless Sensor Networks With Mobile Nodes

    In tree-structured data collection sensor networks, packets are routed towards a sink node by iteratively choosing a node's immediate parent node as the next hop. It is however beyond the scope of these routing protocols to transfer messages along the reverse path, i.e., from the sink to individual nodes in...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2012

    The Influence of Meteorological Variables on the Performance of Outdoor Wireless Local Area Networks

    Improving the performance and the behavior of outdoor Wireless Local Area Networks (WLAN) is a very important objective for almost all researchers in the telematics field. In this paper, a clear relation between the weather and the performance of an outdoor WLAN is shown. This relation is extracted from a...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2012

    Adaptive Provisioning of Stream Processing Systems in the Cloud

    With the advent of data-intensive applications that generate large volumes of real-time data, Distributed Stream Processing Systems (DSPS) become increasingly important in domains such as social networking and web analytics. In practice, DSPSs must handle highly variable workloads caused by unpredictable changes in stream rates. Cloud computing offers an elastic...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2011

    Optimal Radio Access Technology Selection on Heterogeneous Networks

    The joint management of radio resources in heterogeneous networks is considered to improve their capacity. The authors propose joint schemes for admission control and access technology selection with vertical handoffs. Optimal policies are found for wireless networks that support two access techniques and cover the same geographical area. In addition,...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Nov 2011

    Robustness of Optimal Channel Reservation Using Handover Prediction in Multiservice Wireless Networks

    The aim of the authors' study is to obtain theoretical limits for the gain that can be expected when using handover prediction and to determine the sensitivity of the system performance against different parameters. They apply an average-reward Reinforcement Learning (RL) approach based on after states to the design of...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2011

    Scoresheet-Based Event Relevance Determination for Energy Efficiency in Wireless Sensor Networks

    As wireless sensor nodes are mostly battery-powered, energy-efficient operation is a necessity to use their confined energy budget optimally. This is especially true in the logistics domain, where timely and accurate monitoring of containers is required, while the cost pressure is high. Thus, besides the need for energy efficiency, wireless...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2011

    Fault-Tolerant Business Processes

    Service-Oriented Computing (SOC) paradigm promotes the idea of assembling application components into a network of loosely coupled services. Web services are the most promising SOC-based technology. A BPEL process definition represents a composite service that encapsulates some complex business logic including the invocation to other (external) web services. The complexity...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2011

    Converging Multidomain Services in an IMS Environment for IPTV and 3G Networks

    Convergent service environments are required to deal with current tendency to heterogeneity in network contents and its inherent incorporation of more types of devices demanding services from multiple domains. Efficient management architectures are required to tackle issues regarding: media content, subscriber reachability and subscriptions information coming from different types of...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2011

    Tie-RBAC: An Application of RBAC to Social Networks

    This paper explores the application of role-based access control to social networks, from the perspective of social network analysis. Each tie, composed of a relation, a sender and a receiver, involves the sender's assignation of the receiver to a role with permissions. The model is not constrained to system-defined relations...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2010

    Competition in Cognitive Radio Networks: Spectrum Leasing and Innovation

    The paper deals specifically with spectrum leasing within cognitive radio networks and it covers the economic issues that arise when primary users lease spectrum to secondary users. It aims at assessing which benefit mobile users get from the entry of secondary operators in the market. A game theory-based model is...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2010

    Optimal Joint Call Admission Control With Vertical Hando on Heterogeneous Networks

    A joint management of radio resources in heterogeneous networks is considered to raise efficiency. In this paper, the authors focus on joint schemes for admission control and access technology selection using vertical handoff. They study a system where both streaming and elastic traffic are supported, and two radio access technologies...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Business Processes Contextualisation Via Context Analysis

    Context-awareness has emerged as a new perspective for business process modeling. Even though some works have studied it, many challenges have not been addressed yet. There is a clear need for approaches that facilitate the identification of the context properties that influence a business process and provide guidance for correct...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Adaptable Security In Wireless Sensor Networks by Using Reconfigurable ECC Hardware Coprocessors

    Specific features of Wireless Sensor Networks (WSNs) like the open accessibility to nodes, or the easy observability of radio communications, lead to severe security challenges. The application of traditional security schemes on sensor nodes is limited due to the restricted computation capability, low-power availability, and the inherent low data rate....

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Biased Selection for Building Small-World Networks

    Small-world networks are currently present in many distributed applications and can be built augmenting a base network with long-range links using a probability distribution. Currently available distributed algorithms to select these long-range neighbors are designed ad hoc for specific probability distributions. In this paper, the authors propose a new algorithm...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Protecting IEEE 802.11s Wireless Mesh Networks Against Insider Attacks

    IEEE 802.11s is an emerging standard for wireless mesh networks. Networks based on IEEE 802.11s directly benefit from existing security mechanisms in IEEE 802.11. This limits the attack surface of IEEE 802.11s significantly for adversaries that cannot authenticate with the network. Mesh networks are, however, often conceived for community network...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2010

    Analysis of Price Competition Under Peering and Transit Agreements in Internet Service Provision to Peer-to-Peer Users

    Many studies on Internet Service Provider (ISP) interconnection make simplifying assumptions on the implementation of the service provision. The authors' work explicitly models the ISP service that is provided to users that run peer-to-peer applications and it analyses the behavior of competing ISPs. The ISPs have agreed to peer each...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2010

    CReW: Cloud Resilience for Windows Guests Through Monitored Virtualization

    Clouds are complex systems subject to an increasing number of anomalies and threats. In this paper, the authors briefly revisit the issues related to Windows guest cloud service resilience and later provide some preliminary results on the resilience of Windows cloud guests via virtualization. In particular, they propose architecture, Cloud...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Aug 2010

    Using the Semantic Web in Ubiquitous and Mobile Computing: The Morfeo Experience

    With the advent of emerging personal computing paradigms such as ubiquitous and mobile computing, Web contents are becoming accessible from a wide range of mobile devices. Since these devices do not have the same rendering capabilities, Web contents need to be adapted for transparent access from a variety of client...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2010

    Enablers for Adoption of Contingent Technology Production Strategies in Mature Industries

    The paper aims to analyze the correlation between the adoption of technology production strategies and firm competitiveness, considering them under the view of contingent firm theory. In order to test the research hypotheses, the case of the tile ceramic cluster in Spain has been considered. Two surveys were carried out...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2010

    Globally Optimal Triangulations of Minimum Weight Using Ant Colony Optimization Metaheuristic

    Globally optimal triangulations are difficult to be found by deterministic methods as, for most type of criteria, no polynomial algorithm is known. In this paper, the authors consider the Minimum Weight Triangulation (MWT) problem of a given set of n points in the plane. Their aim is to show how...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2010

    Performance Assessment of Hybrid Data Fusion and Tracking Algorithms

    This paper presents an overview on the performance of hybrid data fusion and tracking algorithms evaluated in the WHERE consortium. The focus is on three scenarios. For the small scale indoor scenario with Ultra WideBand (UWB) complementing cellular communication systems, the accuracy can vary in time as a connectivity-dependent random...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2010

    Enterprise Engineering Approach for Business and IS/IT Strategic Alignment

    IS/IT strategies usually depend on a business strategy. The alignment between both strategies improves these strategic plans. Business and IS/IT alignment is the degree to which the strategy of IS/IT supports and is supported by the business strategy. This paper review the strategic alignment between business and IS/IT and propose...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2010

    Configuring the Variability of Business Process Models Using Non-Functional Requirements

    The existence of variations in the organizational environment makes the configuration of business process models a complex activity, even for experienced business analysts. The increasing adoption of business processes models by software engineers as an input for requirements analysis strengthens the importance of addressing this issue. The challenge is to...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2010

    A Goal-Oriented Approach for Variability in BPMN

    Good business processes need to be up-to-date and automated to represent the organizational environment. To obtain models that reflect the changes it is necessary continuous checking between model and reality. Thus, business process model need to be modifiable and transformable in software. In order satisfy these needs the authors propose...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jan 2010

    Towards a Framework for Resource Usage Verification and Debugging in the CiaoPP System

    This paper presents a framework for (static) verification of general resource usage program properties. The framework extends the criteria of correctness as the conformance of a program to a specification expressing non-functional global properties (e.g., upper and lower bounds on execution time, memory, power, or user defined resources). Such bounds...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jan 2010

    Robust Admission Control for Streaming and Elastic Services in Cellular Networks

    The specific features of cellular networks and especially terminal mobility make the Session Admission Control (SAC) in such networks more complex. This paper studies the robustness of the Virtual Partitioning (VP) admission policy in connection with multiservice cellular networks and considering streaming and elastic traffic in scenarios that must support...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2009

    A Multistandard Frequency Offset Synchronization Scheme for 802.11n, 802.16d, LTE, and DVB-T/H Systems

    Carrier Frequency Offset (CFO) synchronization is a crucial issue in the implementation of Orthogonal Frequency Division Multiplexing (OFDM) systems. Since current technology tends to implement different standards in the same wireless device, a common frequency synchronization structure is desirable. Knowledge of the physical frame and performance and cost system requirements...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2009

    Optimal Admission Control in Cognitive Radio Networks

    The authors study a cognitive radio system in which the spectrum handover technique is applied by secondary users when they have to vacate a channel due to a primary user arrival. In order to limit the forced termination probability of secondary users a fractional guard channel reservation scheme is applied...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Aug 2009

    A Power-aware Hybrid RAM-CAM Renaming Mechanism for Fast Recovery

    Modern superscalar processors implement register renaming by using either RAM or CAM tables. The design of these structures should address their access time and misprediction recovery penalty. While direct-mapped RAMs provide faster access times, CAMs are more appropriate to avoid recovery penalties. Although they are more complex and slower, CAMs...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2007

    Leakage Current Reduction in Data Caches on Embedded Systems

    Now-a-days, embedded systems can be found in a wide range of pervasive devices (e.g., smart phones, PDAs, or video/digital cameras). These devices contain large cache memories, whose power consumption can reach about 50% of the total spent energy, from which leakage energy is the predominant fraction in current technologies. In...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2006

    Applying the Zeros Switch-Off Technique to Reduce Static Energy in Data Caches

    Cache memories occupy a high percentage of silicon area. This fact has motivated a large number of research works to be focused on alternative organizations of conventional caches: if the cache area is reduced without losing performance, the corresponding space can be dedicated to improve other processor parts. Recently, the...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2007

    Multi2Sim: A Simulation Framework to Evaluate Multicore-Multithreaded Processors

    Current microprocessors are based in complex designs, integrating different components on a single chip, such as hardware threads, processor cores, memory hierarchy or interconnection networks. The permanent need of evaluating new designs on each of these components motivates the development of tools which simulate the system working as a whole....

    Provided By Universidad Politecnica de Madrid

  • White Papers // Nov 2008

    Power Reduction in Advanced Embedded IPC Processors

    Now-a-days, embedded systems are found in a wide range of pervasive devices (e.g., smart phones, PDAs, or digital cameras). These devices contain large cache memories, whose power consumption can reach about 50% of the total spent energy, from which leakage energy is the predominant fraction in current technologies. This paper...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jan 2008

    The Impact of Out-of-Order Commit in Coarse-Grain, Fine-Grain and Simultaneous Multithreaded Architectures

    Multithreaded processors in their different organizations (simultaneous, coarse grain and fine grain) have been shown as effective architectures to reduce the issue waste. On the other hand, retiring instructions from the pipeline in an out-of-order fashion helps to unclog the ROB when a long latency instruction reaches its head. This...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2009

    An Efficient Low-Complexity Alternative to the ROB for Out-of-Order Retirement of Instructions

    Current superscalar processors use a Re-Order Buffer (ROB) to support speculation, precise exceptions, and register reclamation. Instructions are retired from this structure in program order, which may lead to significant performance degradation if a long latency operation blocks the ROB head. In this paper, a checkpoint-free out-of-order commit architecture is...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2009

    Paired ROBs: A Cost-Effective Reorder Buffer Sharing Strategy for SMT Processors

    An important design issue of SMT processors is to find proper sharing strategies of resources among threads. This paper proposes a ROB sharing strategy, called paired ROB that considers the fact that task parallelism is not always available to fully utilize resources of multithreaded processors. To this aim, an evaluation...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2009

    A Complexity-Effective Out-of-Order Retirement Microarchitecture

    Current superscalar processors commit instructions in program order by using a Re-Order Buffer (ROB). The ROB provides support for speculation, precise exceptions, and register reclamation. However, committing instructions in program order may lead to significant performance degradation if a long latency operation blocks the ROB head. Several proposals have been...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jan 2014

    Edinet: An Execution Driven Interconnection Network Simulator for DSM Systems

    Interconnection network evaluation studies usually assume that the workload generated by actual applications can be modeled by synthetic workloads. Constant message generation rate (equal for all nodes), uniform distribution of message destinations (with or without locality) and fixed traffic patterns are frequently used. Evaluation studies on interconnection networks for distributed...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2013

    XtratuM Hypervisor Redesign for LEON4 Multicore Processor

    XtratuM is an open source hypervisor that uses para-virtualization techniques designed to comply with safety critical real-time requirements. Several projects aimed to de ne a reference architecture for space on-board systems have adopted XtratuM as a virtualization layer in order to enforce the strong spatial and temporal isolation between software...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2007

    The Validation Buffer Microarchitecture for Multithreaded Processors

    Multi-Threaded (MT) processors reduce the waste of issue width by executing instructions from multiple threads at the same time. On the other hand, Out-of-Order Commit (OOC) processors have been recently proposed as an efficient way of avoiding pipeline stalls when a long-latency instruction reaches the commit stage. In this paper,...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jan 2010

    Towards a Framework for Resource Usage Verification and Debugging in the CiaoPP System

    This paper presents a framework for (static) verification of general resource usage program properties. The framework extends the criteria of correctness as the conformance of a program to a specification expressing non-functional global properties (e.g., upper and lower bounds on execution time, memory, power, or user defined resources). Such bounds...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Aug 2010

    Using the Semantic Web in Ubiquitous and Mobile Computing: The Morfeo Experience

    With the advent of emerging personal computing paradigms such as ubiquitous and mobile computing, Web contents are becoming accessible from a wide range of mobile devices. Since these devices do not have the same rendering capabilities, Web contents need to be adapted for transparent access from a variety of client...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2009

    Characterising Equilibrium Logic and Nested Logic Programs: Reductions and Complexity

    Equilibrium logic is an approach to non-monotonic reasoning that extends the stable-model and answer-set semantics for logic programs. In particular, it includes the general case of nested logic programs, where arbitrary Boolean combinations are permitted in heads and bodies of rules, as special kinds of theories. In this paper, the...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2010

    CReW: Cloud Resilience for Windows Guests Through Monitored Virtualization

    Clouds are complex systems subject to an increasing number of anomalies and threats. In this paper, the authors briefly revisit the issues related to Windows guest cloud service resilience and later provide some preliminary results on the resilience of Windows cloud guests via virtualization. In particular, they propose architecture, Cloud...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2009

    PolyVaccine: Protecting Web Servers Against Zero-Day, Polymorphic and Metamorphic Exploits

    Today web servers are ubiquitous having become critical infrastructures of many organizations. However, they are still one of the most vulnerable parts of organizations infrastructure. Exploits are many times used by worms to fast propagate across the full Internet being web servers one of their main targets. New exploit techniques...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Adaptable Security In Wireless Sensor Networks by Using Reconfigurable ECC Hardware Coprocessors

    Specific features of Wireless Sensor Networks (WSNs) like the open accessibility to nodes, or the easy observability of radio communications, lead to severe security challenges. The application of traditional security schemes on sensor nodes is limited due to the restricted computation capability, low-power availability, and the inherent low data rate....

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Biased Selection for Building Small-World Networks

    Small-world networks are currently present in many distributed applications and can be built augmenting a base network with long-range links using a probability distribution. Currently available distributed algorithms to select these long-range neighbors are designed ad hoc for specific probability distributions. In this paper, the authors propose a new algorithm...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2010

    Performance Assessment of Hybrid Data Fusion and Tracking Algorithms

    This paper presents an overview on the performance of hybrid data fusion and tracking algorithms evaluated in the WHERE consortium. The focus is on three scenarios. For the small scale indoor scenario with Ultra WideBand (UWB) complementing cellular communication systems, the accuracy can vary in time as a connectivity-dependent random...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2009

    A Multistandard Frequency Offset Synchronization Scheme for 802.11n, 802.16d, LTE, and DVB-T/H Systems

    Carrier Frequency Offset (CFO) synchronization is a crucial issue in the implementation of Orthogonal Frequency Division Multiplexing (OFDM) systems. Since current technology tends to implement different standards in the same wireless device, a common frequency synchronization structure is desirable. Knowledge of the physical frame and performance and cost system requirements...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2012

    The Influence of Meteorological Variables on the Performance of Outdoor Wireless Local Area Networks

    Improving the performance and the behavior of outdoor Wireless Local Area Networks (WLAN) is a very important objective for almost all researchers in the telematics field. In this paper, a clear relation between the weather and the performance of an outdoor WLAN is shown. This relation is extracted from a...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2010

    Globally Optimal Triangulations of Minimum Weight Using Ant Colony Optimization Metaheuristic

    Globally optimal triangulations are difficult to be found by deterministic methods as, for most type of criteria, no polynomial algorithm is known. In this paper, the authors consider the Minimum Weight Triangulation (MWT) problem of a given set of n points in the plane. Their aim is to show how...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jul 2011

    Fault-Tolerant Business Processes

    Service-Oriented Computing (SOC) paradigm promotes the idea of assembling application components into a network of loosely coupled services. Web services are the most promising SOC-based technology. A BPEL process definition represents a composite service that encapsulates some complex business logic including the invocation to other (external) web services. The complexity...

    Provided By Universidad Politecnica de Madrid

  • White Papers // May 2011

    Tie-RBAC: An Application of RBAC to Social Networks

    This paper explores the application of role-based access control to social networks, from the perspective of social network analysis. Each tie, composed of a relation, a sender and a receiver, involves the sender's assignation of the receiver to a role with permissions. The model is not constrained to system-defined relations...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2012

    Adaptive Provisioning of Stream Processing Systems in the Cloud

    With the advent of data-intensive applications that generate large volumes of real-time data, Distributed Stream Processing Systems (DSPS) become increasingly important in domains such as social networking and web analytics. In practice, DSPSs must handle highly variable workloads caused by unpredictable changes in stream rates. Cloud computing offers an elastic...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jun 2011

    Converging Multidomain Services in an IMS Environment for IPTV and 3G Networks

    Convergent service environments are required to deal with current tendency to heterogeneity in network contents and its inherent incorporation of more types of devices demanding services from multiple domains. Efficient management architectures are required to tackle issues regarding: media content, subscriber reachability and subscriptions information coming from different types of...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2010

    Competition in Cognitive Radio Networks: Spectrum Leasing and Innovation

    The paper deals specifically with spectrum leasing within cognitive radio networks and it covers the economic issues that arise when primary users lease spectrum to secondary users. It aims at assessing which benefit mobile users get from the entry of secondary operators in the market. A game theory-based model is...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Dec 2010

    Optimal Joint Call Admission Control With Vertical Hando on Heterogeneous Networks

    A joint management of radio resources in heterogeneous networks is considered to raise efficiency. In this paper, the authors focus on joint schemes for admission control and access technology selection using vertical handoff. They study a system where both streaming and elastic traffic are supported, and two radio access technologies...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2010

    Analysis of Price Competition Under Peering and Transit Agreements in Internet Service Provision to Peer-to-Peer Users

    Many studies on Internet Service Provider (ISP) interconnection make simplifying assumptions on the implementation of the service provision. The authors' work explicitly models the ISP service that is provided to users that run peer-to-peer applications and it analyses the behavior of competing ISPs. The ISPs have agreed to peer each...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Jan 2010

    Robust Admission Control for Streaming and Elastic Services in Cellular Networks

    The specific features of cellular networks and especially terminal mobility make the Session Admission Control (SAC) in such networks more complex. This paper studies the robustness of the Virtual Partitioning (VP) admission policy in connection with multiservice cellular networks and considering streaming and elastic traffic in scenarios that must support...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Sep 2009

    Modeling and Characterization of Spectrum White Spaces for Underlay Cognitive Radio Networks

    Cognitive Radio (CR) networks are envisaged as the key technology to realize dynamic spectrum access and solving the scarcity of radio spectrum. Having a temporal characterization of the spectrum white spaces in the primary network is a key element for studying and designing radio resource management mechanisms in CR networks....

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2009

    Optimal Admission Control in Cognitive Radio Networks

    The authors study a cognitive radio system in which the spectrum handover technique is applied by secondary users when they have to vacate a channel due to a primary user arrival. In order to limit the forced termination probability of secondary users a fractional guard channel reservation scheme is applied...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2013

    Integrating Wireless Sensor Nodes and Smartphones for Energy-Efficient Data Exchange in Smart Environments

    To effectively exploit the potential of smart environments, an energy-efficient data exchange between the smart environment infrastructure and its users is necessary. Usually, a major building block of smart environments is different sensors, which typically communicate making use of the IEEE 802.15.4 standard. Opposed to this, users in a smart...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Mar 2013

    Pre-Allocating Code Mappings for Energy-Efficient Data Encoding in Wireless Sensor Networks

    Energy is a scarce resource on battery-powered wireless sensor nodes, and wireless communication represents the major consumer of electric energy on most current platforms. Reducing the number and size of radio transmissions thus represents a viable approach to save energy and extend a node's operational time. In the domain of...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2012

    Electric Appliance Classification Based on Distributed High Resolution Current Sensing

    Today's solutions to inform residents about their electricity consumption are mostly confined to displaying aggregate readings collected at meter level. A reliable identification of appliances that require disproportionate amounts of energy for their operation is generally unsupported by these systems, or at least requires significant manual configuration efforts. The authors...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2010

    Protecting IEEE 802.11s Wireless Mesh Networks Against Insider Attacks

    IEEE 802.11s is an emerging standard for wireless mesh networks. Networks based on IEEE 802.11s directly benefit from existing security mechanisms in IEEE 802.11. This limits the attack surface of IEEE 802.11s significantly for adversaries that cannot authenticate with the network. Mesh networks are, however, often conceived for community network...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Oct 2012

    Distributed Data Filtering in Logistics Wireless Sensor Networks Based on Transmission Relevance

    Energy-efficient operation is mandatory in wireless sensor networks due to the limited energy budget of sensor nodes. Considering the potential application of wireless sensor networks in logistics, cost efficiency is another major requirement due to high cost pressure. To save on data transmissions within such sensor deployments, which account for...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Apr 2013

    Dynamic Spectrum Sharing in Cognitive Radio Networks Using Truthful Mechanisms and Virtual Currency

    In cognitive radio networks, there are scenarios where Secondary Users (SUs) utilize opportunistically the spectrum originally allocated to Primary Users (PUs). The spectrum resources available to SUs fluctuate over time due to PUs activity, SUs mobility and competition between SUs. In order to utilize these resources efficiently spectrum sharing techniques...

    Provided By Universidad Politecnica de Madrid

  • White Papers // Apr 2013

    A Model of Resource Management in Small Cells With Dynamic Traffic and Backhaul Constraints

    During the last years, the volume of data-traffic carried by mobile cellular networks has experienced a major growth and progress. The current networks' features are not enough to face this development paradigm and the novel concept of small cells has emerged to increase the network capacity. However, the deployment of...

    Provided By Universidad Politecnica de Madrid