Imperial College London

Displaying 41-80 of 164 results

  • White Papers // Sep 2011

    Energy Efficient Resource Allocation Strategy for Cloud Data Centres

    Cloud computing data centres are emerging as new candidates for replacing traditional data centres. Cloud data centres are growing rapidly in both number and capacity to meet the increasing demands for highly-responsive computing and massive storage. Making the data centre more energy efficient is a necessary task. In this paper,...

    Provided By Imperial College London

  • White Papers // Aug 2011

    Solving a Positive Definite System of Linear Equations Via the Matrix Exponential

    The authors present a new direct algorithm for solving a system of linear equations with a positive definite matrix by discretizing a continuous-time dynamical system for a large sampling time. The obtained algorithm is highly fine-grain parallelizable and its computational complexity grows logarithmically with respect to the condition number of...

    Provided By Imperial College London

  • White Papers // Aug 2011

    A New Distributed Optimization Framework for Hybrid Ad-Hoc Networks

    The continuously increasing demand for resources in modern networks urges for more efficient resource allocation. Such an allocation of resources to network users can be formulated as an optimization problem. However, the existence of wireless links in modern networks and the competition for resources by multimedia applications turn the optimization...

    Provided By Imperial College London

  • White Papers // Jun 2011

    Unifying Finite Difference Option-pricing for Hardware Acceleration

    Explicit finite difference method is widely used in finance for pricing many kinds of options. Its regular computational pattern makes it an ideal candidate for acceleration using reconfigurable hardware. However, because the corresponding hardware designs must be optimized both for the specific option and for the target platform, it is...

    Provided By Imperial College London

  • White Papers // Jun 2011

    CusComNet: A Customisable Network for Reconfigurable Heterogeneous Clusters

    Computer clusters equipped with reconfigurable accelerators have shown promise in high performance computing. This paper explores novel ways of customizing data communication between accelerator nodes, which is often a bottleneck when scaling up the cluster size. Based on the direct connection of high speed serial links between advanced reconfigurable devices,...

    Provided By Imperial College London

  • White Papers // Jun 2011

    Hierarchical Mobility Control for Data Ferries Under Constrained Message Delays

    The authors consider the problem of controlling mobile data ferries for message delivery among disconnected, scattered domains in a highly partitioned network. Existing work on data ferry control mostly focuses on predetermined ferry routes, assuming full observations at the ferry and no explicit Quality of Service (QoS) constraints on the...

    Provided By Imperial College London

  • White Papers // Jun 2011

    The Emergence Of Leadership In Social Networks

    The authors study a networked version of the minority game in which agents can choose to follow the choices made by a neighbouring agent in a social network. They show that for a wide variety of networks a leadership structure always emerges, with most agents following the choice made by...

    Provided By Imperial College London

  • White Papers // May 2011

    Intelligent Navigation Systems for Building Evacuation

    Intelligent navigation systems can significantly improve the evacuation of civilians in urban emergencies by providing dynamic directions to the evacuees as the hazard spreads. In this paper, the authors propose two distributed and adaptive systems for building evacuation. The first system, called Intelligent Evacuation System (IES), is composed of a...

    Provided By Imperial College London

  • White Papers // May 2011

    Rule-Based Verification of Network Protocol Implementations Using Symbolic Execution

    The secure and correct implementation of network protocols for resource discovery, device configuration and network management is complex and error-prone. Protocol specifications contain ambiguities, leading to implementation flaws and security vulnerabilities in network daemons. Such problems are hard to detect because they are often triggered by complex sequences of packets...

    Provided By Imperial College London

  • White Papers // May 2011

    Packets Traveling in Non-Homogeneous Networks

    This paper considers a probability model for travel of a packet from a source node to a destination node in a large non-homogeneous multiple hop network with unreliable routing tables. Use of a random model is justified by the lack of precise information that can be used in each step...

    Provided By Imperial College London

  • White Papers // Apr 2011

    Markovian Workload Characterization for QoS Prediction in the Cloud

    Resource allocation in the cloud is usually driven by performance predictions, such as estimates of the future incoming load to the servers or of the Quality-of-Service (QoS) offered by applications to end users. In this context, characterizing web workload fluctuations in an accurate way is fundamental to understand how to...

    Provided By Imperial College London

  • White Papers // Apr 2011

    PHP Aspis: Using Partial Taint Tracking to Protect Against Injection Attacks

    Web applications are increasingly popular victims of security attacks. Injection attacks, such as Cross Site Scripting or SQL Injection, are a persistent problem. Even though developers are aware of them, the suggested best practices for protection are error prone: unless all user input is consistently filtered, any application may be...

    Provided By Imperial College London

  • White Papers // Apr 2011

    YA-MAC: Handling Unified Unicast and Broadcast Traffic in Multi-Hop Wireless Sensor Networks

    This paper introduces YA-MAC, an agile Medium Access Control (MAC) protocol to provide high throughput for both unicast and broadcast traffic in Duty-Cycled Multi-hop Wireless Sensor Networks (DCM-WSN). YA-MAC is implemented under the UPMA framework in TinyOS and is evaluated on TelosB and MicaZ testbeds. The authors observe that YAMAC...

    Provided By Imperial College London

  • White Papers // Apr 2011

    Approximate Analysis of Blocking Queueing Networks with Temporal Dependence

    In this paper, the authors extend the class of MAP queueing networks to include blocking models, which are useful to describe the performance of service instances which have a limited concurrency level. They consider two different blocking mechanisms: Repetitive Service-Random Destination (RS-RD) and Blocking After Service (BAS). They propose a...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Energy-Aware Routing in the Cognitive Packet Network

    An Energy Aware Routing Protocol (EARP) is proposed to minimise a performance metric that combines the total consumed power in the network and the QoS that is specified for the flows. The algorithm uses source routing based on the functionalities provided by the Cognitive Packet Network (CPN), running autonomously at...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Noise, Risk Premium, And Bubble

    The existence of the pricing kernel is shown to imply the existence of an ambient information process that generates market filtration. This information process consists of a signal component concerning the value of the random variable X that can be interpreted as the timing of future cash demand, and an...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Network Routing Control With G-Networks

    G-Networks are queueing networks in which the novel idea of 'Negative customers' has been introduced. In contrast with the regular customers, called positive customers and treated in the normal way by a server, negative customers are also included. "Negative customers" and "Signals" can act in the network in several ways:...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Constrained Mixture Models For Asset Returns Modelling

    The estimation of asset return distributions is crucial for determining optimal trading strategies. In this paper, the authors describe the constrained mixture model, based on a mixture of Gamma and Gaussian distributions, to provide an accurate description of price trends as being clearly positive, negative or ranging while accounting for...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Unobtrusive Behavioral and Activity-Related Multimodal Biometrics: The ACTIBIO Authentication Concept

    Unobtrusive Authentication using ACTIvity-Related and Soft BIOmetrics (ACTIBIO) is an EU Specific Targeted REsearch Project (STREP) where new types of biometrics are combined with state-of-the-art unobtrusive technologies in order to enhance security in a wide spectrum of applications. The project aims to develop a modular, robust, multimodal biometrics security authentication...

    Provided By Imperial College London

  • White Papers // Jan 2011

    UKAIRO: Internet-Scale Bandwidth Detouring

    The performance of content distribution on the Internet is crucial for many services. While popular content can be delivered efficiently to users by caching it using content delivery networks, the distribution of less popular content is often constrained by the bandwidth of the Internet path between the content server and...

    Provided By Imperial College London

  • White Papers // Jan 2011

    Application Specific Memory Access, Reuse and Reordering for SDRAM

    The efficient use of bandwidth available on an external SDRAM interface is strongly dependent on the sequence of addresses requested. The On-chip memory buffers can make possible data reuse and request reordering which together ensure bandwidth on an SDRAM interface is used efficiently. This paper outlines an automated procedure for...

    Provided By Imperial College London

  • White Papers // Nov 2010

    SQPR: Stream Query Planning With Reuse

    When users submit new queries to a Distributed Stream Processing System (DSPS), a query planner must allocate physical resources, such as CPU cores, memory and network bandwidth, from a set of hosts to queries. Allocation decisions must provide the correct mix of resources required by queries, while achieving an efficient...

    Provided By Imperial College London

  • White Papers // Nov 2010

    Multiplicity Computing: A Vision of Software Engineering for Next-Generation Computing Platform Applications

    New technologies have recently emerged to challenge the very nature of computing: multicore processors, virtualized operating systems and networks, and data-center clouds. One can view these technologies as forming levels within a new, global computing platform. The authors aim to open a new area of research, called multiplicity computing, that...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Safe Parallel Programming With Session Java

    The session-typed programming language Session Java (SJ) has proved to be an effective tool for distributed programming, promoting productivity and compile-time safety. This paper investigates the use of SJ for session-typed parallel programming, and introduces new language primitives for chained iteration and multi-channel communication. These primitives allow the efficient coordination...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Conditional Density Models For Asset Pricing

    The authors model the dynamics of asset prices and associated derivatives by consideration of the dynamics of the conditional probability density process for the value of an asset at some specified time in the future. In the case where the asset is driven by Brownian motion, an associated "Master equation"...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Constrained Nonsmooth Utility Maximization On The Positive Real Line

    The authors maximize the expected utility of terminal wealth in an incomplete market where there are cone constraints on the investor's portfolio process and the utility function is not assumed to be strictly concave or differentiable. They establish the existence of the optimal solutions to the primal and dual problems...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Simulating the Power Consumption of Computer Networks

    The authors introduce a high-fidelity simulation model to evaluate the power consumption of computer networks derived from measured data on routers. To this end, they design and use a power consumption profiling system to parameterize the electrical power consumption of network elements in terms of data traffic. A model validation...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Information-Based Models For Finance And Insurance

    In financial markets, the information that traders have about an asset is reflected in its price. The arrival of new information then leads to price changes. The 'Information-based framework' of Brody, Hughston and Macrina (BHM) isolates the emergence of information, and examines its role as a driver of price dynamics....

    Provided By Imperial College London

  • White Papers // Sep 2010

    IO Performance Prediction in Consolidated Virtualized Environments

    The authors proposed a trace-driven approach to predict the performance degradation of disk request response times due to storage device contention in consolidated virtualized environments. Their performance model evaluates a queueing network with fair share scheduling using trace-driven simulation. The model parameters can be deduced from measurements obtained inside Virtual...

    Provided By Imperial College London

  • White Papers // Sep 2010

    An FPGA Implementation of a Sparse Quadratic Programming Solver for Constrained Predictive Control

    Model Predictive Control (MPC) is an advanced industrial control technique that relies on the solution of a Quadratic Programming (QP) problem at every sampling instant to determine the input action required to control the current and future behavior of a physical system. Its ability in handling large Multiple Input Multiple...

    Provided By Imperial College London

  • White Papers // Sep 2010

    Asset Pricing With Random Information Flow

    In the information-based approach to asset pricing the market filtration is modeled explicitly as a superposition of signals concerning relevant market factors and independent noise. The rate at which the signal is revealed to the market then determines the overall magnitude of asset volatility. By letting this information flow rate...

    Provided By Imperial College London

  • White Papers // Sep 2010

    A Fast Well-conditioned Interior Point Method for Predictive Control

    Interior Point Methods (IPMs) have proven to be an efficient way of solving quadratic programming problems in predictive control. A linear system of equations needs to be solved in each iteration of an IPM. The ill-conditioning of this linear system in the later iterations of the IPM prevents the use...

    Provided By Imperial College London

  • White Papers // Sep 2010

    FPGA Implementation of an Interior Point Solver for Linear Model Predictive Control

    Automatic control, the process of measuring, computing, and applying an input to control the behavior of a physical system, is ubiquitous in engineering and industry. Model Predictive Control (MPC) is an advanced control technology that has been very successful in the chemical process industries due to its ability to handle...

    Provided By Imperial College London

  • White Papers // Sep 2010

    Towards a Radio-Controlled Time Synchronized Wireless Sensor Network

    Wireless sensor networks are deployed to monitor real-world phenomena, and are seeing growing demand in commerce and industry. These networks can benefit from time synchronized clocks on distributed nodes. The precision of time synchronization depends on error elimination or reliable estimation of errors associated with synchronization message delays. This paper...

    Provided By Imperial College London

  • White Papers // Aug 2010

    A Sensor Network to Profile the Electrical Power Consumption of Computer Networks

    The authors introduce a sensor network to measure the individual power consumption of a large number of network elements in near-real time. A main application of this system is to obtain profiles of the power usage of network elements, i.e., a parameterization of power consumption with respect to workload. They...

    Provided By Imperial College London

  • White Papers // Aug 2010

    A Distributed Admission Control Mechanism for Multi-Criteria QoS

    Admission control based on multiple criteria has always been a desirable feature for computer networks. In the past, the authors presented such a system, but it was based on a centralised decision mechanism, which by itself constitutes a significant limitation. Here, they describe a decentralised version of the initial admission...

    Provided By Imperial College London

  • White Papers // Aug 2010

    Random Neural Network for Emergency Management

    The authors consider decision problems in emergency management, such as simultaneously dispatching emergency teams to locations where incidents have occurred, and propose an algorithmic solution using the Random Neural Network. This is an NP-hard optimization problem, but the approach they suggest is solved in polynomial time, and is also distributed...

    Provided By Imperial College London

  • White Papers // Jul 2010

    A Test-Based Scheduling Protocol (TBSP) for Periodic Data Gathering in Wireless Sensor Networks

    The authors propose TBSP, a TDMA protocol for gathering information periodically from multiple data sources to a central location across multiple hops. TBSP incurs a lower overhead than the existing protocols because it only requires the sensor nodes to keep track of their own schedule, whereas in the existing protocols...

    Provided By Imperial College London

  • White Papers // Jul 2010

    Routing and G-Networks to Optimise Energy and Quality of Service in Packet Networks

    The authors formulate the problem of joint energy and Quality of Service (QoS) optimisation in packet networks and show how it can be formalised using the control capabilities inherent in G-network theory, which also includes the overhead due to control traffic. Using known energy consumption characteristics of network routers and...

    Provided By Imperial College London

  • White Papers // Jul 2010

    Activity Related Biometrics Based on Motion Trajectories

    This paper contributes to the concept of activity-related biometric authentication in ambient Intelligence environments. The motivation behind the proposed approach derives from activity-related biometrics and is mainly focusing on everyday activities. The activity sequence is captured by a stereoscopic camera and the resulting 2.5D data are processed to extract valuable...

    Provided By Imperial College London

  • White Papers // Aug 2011

    A New Distributed Optimization Framework for Hybrid Ad-Hoc Networks

    The continuously increasing demand for resources in modern networks urges for more efficient resource allocation. Such an allocation of resources to network users can be formulated as an optimization problem. However, the existence of wireless links in modern networks and the competition for resources by multimedia applications turn the optimization...

    Provided By Imperial College London

  • White Papers // Nov 2008

    MIMO Routing With QoS Provisioning

    Multiple-Input-Multiple-Output (MIMO) transceivers can take advantage of random channel fading and multi-path delay spread for multiplying transfer rates (multiplexing gain), improve transmission quality/reliability (diversity gain) at no cost of extra spectrum, or allow the spatial separation of the signals of different transceivers in a multi-user scenario, thus providing a multiple-access...

    Provided By Imperial College London

  • White Papers // Apr 2013

    Low-Complexity Scheduling Policies for Energy Harvesting Communication Networks

    A time-slotted multiple access wireless system with N transmitting nodes, each equipped with an Energy Harvesting (EH) device and a rechargeable battery of finite capacity, is studied. The energy arrival process at each node is modeled as an independent two-state Markov process, such that a node either harvests one unit...

    Provided By Imperial College London

  • White Papers // May 2013

    Mobile Network Anomaly Detection and Mitigation: The NEMESYS Approach

    Mobile malware and mobile network attacks are becoming a significant threat that accompanies the increasing popularity of smart phones and tablets. Thus in this paper, the authors present their research vision that aims to develop a network-based security solution combining analytical modeling, simulation and learning, together with billing and control-plane...

    Provided By Imperial College London

  • White Papers // Jul 2010

    An Empirical Study of the Scalability of Performance Analysis Tools in the Cloud

    Calculation of performance metrics such as steady state probabilities and response time distributions in large Markov and semi-Markov models can be accomplished using parallel implementations of well-known numerical techniques. In this paper the authors investigate the scalability of two existing parallel performance analysis tools (one based on Laplace transform inversion...

    Provided By Imperial College London

  • White Papers // Jun 2012

    Lightweight Resource Scaling for Cloud Applications

    Elastic resource provisioning is a key feature of cloud computing, allowing users to scale up or down resource allocation for their applications at run-time. To date, most practical approaches to managing elasticity are based on allocation/de-allocation of the Virtual Machine (VM) instances to the application. This VM-level elasticity typically incurs...

    Provided By Imperial College London

  • White Papers // Mar 2012

    MODACLOUDS, a Model-Driven Approach for the Design and Execution of Applications on Multiple Clouds

    Cloud computing is emerging as a major trend in the ICT industry. While most of the attention of the research community is focused on considering the perspective of the Cloud providers, offering mechanisms to support scaling of resources and interoperability and federation between Clouds, the perspective of developers and operators...

    Provided By Imperial College London

  • White Papers // Jun 2009

    Data Acquisition and Error Analysis for Pepperpot Emittance Measurements

    The pepperpot provides a unique and fast method of measuring emittance, providing four dimensional correlated beam measurements for both transverse planes. In order to make such a correlated measurement, the pepperpot must sample the beam at specific intervals. Such discontinuous data, and the unique characteristics of the pepperpot assembly, requires...

    Provided By Imperial College London

  • White Papers // Sep 2009

    Route Capacity Estimation Based Admission Control and QoS Routing for Mesh Networks

    Wireless Mesh Networks (WMNs) is a promising key technology for next generation wireless backhauling that is expected to support various types of applications with different Quality-of-Service (QoS) demands. Advanced antenna techniques, novel scheduling algorithms and routing schemes have attracted increased research interests aiming to optimize the performance of WMNs and...

    Provided By Imperial College London

  • White Papers // Oct 2009

    Creating a Digital Ecosystem: Service-Oriented Architectures With Distributed Evolutionary Computing

    The authors start with a discussion of the relevant literature, including Nature Inspired Comuting as a framework in which to understand this work, and the process of biomimicry to be used in mimicking the necessary biological processes to create Digital Ecosystems. They then consider the relevant theoretical ecology in creating...

    Provided By Imperial College London

  • White Papers // Jun 2011

    The Emergence Of Leadership In Social Networks

    The authors study a networked version of the minority game in which agents can choose to follow the choices made by a neighbouring agent in a social network. They show that for a wide variety of networks a leadership structure always emerges, with most agents following the choice made by...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Noise, Risk Premium, And Bubble

    The existence of the pricing kernel is shown to imply the existence of an ambient information process that generates market filtration. This information process consists of a signal component concerning the value of the random variable X that can be interpreted as the timing of future cash demand, and an...

    Provided By Imperial College London

  • White Papers // Mar 2011

    Constrained Mixture Models For Asset Returns Modelling

    The estimation of asset return distributions is crucial for determining optimal trading strategies. In this paper, the authors describe the constrained mixture model, based on a mixture of Gamma and Gaussian distributions, to provide an accurate description of price trends as being clearly positive, negative or ranging while accounting for...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Conditional Density Models For Asset Pricing

    The authors model the dynamics of asset prices and associated derivatives by consideration of the dynamics of the conditional probability density process for the value of an asset at some specified time in the future. In the case where the asset is driven by Brownian motion, an associated "Master equation"...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Constrained Nonsmooth Utility Maximization On The Positive Real Line

    The authors maximize the expected utility of terminal wealth in an incomplete market where there are cone constraints on the investor's portfolio process and the utility function is not assumed to be strictly concave or differentiable. They establish the existence of the optimal solutions to the primal and dual problems...

    Provided By Imperial College London

  • White Papers // Oct 2010

    Information-Based Models For Finance And Insurance

    In financial markets, the information that traders have about an asset is reflected in its price. The arrival of new information then leads to price changes. The 'Information-based framework' of Brody, Hughston and Macrina (BHM) isolates the emergence of information, and examines its role as a driver of price dynamics....

    Provided By Imperial College London

  • White Papers // Apr 2011

    YA-MAC: Handling Unified Unicast and Broadcast Traffic in Multi-Hop Wireless Sensor Networks

    This paper introduces YA-MAC, an agile Medium Access Control (MAC) protocol to provide high throughput for both unicast and broadcast traffic in Duty-Cycled Multi-hop Wireless Sensor Networks (DCM-WSN). YA-MAC is implemented under the UPMA framework in TinyOS and is evaluated on TelosB and MicaZ testbeds. The authors observe that YAMAC...

    Provided By Imperial College London

  • White Papers // May 2011

    Rule-Based Verification of Network Protocol Implementations Using Symbolic Execution

    The secure and correct implementation of network protocols for resource discovery, device configuration and network management is complex and error-prone. Protocol specifications contain ambiguities, leading to implementation flaws and security vulnerabilities in network daemons. Such problems are hard to detect because they are often triggered by complex sequences of packets...

    Provided By Imperial College London

  • White Papers // Apr 2011

    PHP Aspis: Using Partial Taint Tracking to Protect Against Injection Attacks

    Web applications are increasingly popular victims of security attacks. Injection attacks, such as Cross Site Scripting or SQL Injection, are a persistent problem. Even though developers are aware of them, the suggested best practices for protection are error prone: unless all user input is consistently filtered, any application may be...

    Provided By Imperial College London

  • White Papers // Nov 2010

    Multiplicity Computing: A Vision of Software Engineering for Next-Generation Computing Platform Applications

    New technologies have recently emerged to challenge the very nature of computing: multicore processors, virtualized operating systems and networks, and data-center clouds. One can view these technologies as forming levels within a new, global computing platform. The authors aim to open a new area of research, called multiplicity computing, that...

    Provided By Imperial College London

  • White Papers // Apr 2010

    Enforcing User Privacy in Web Applications Using Erlang

    Social networking applications on the web handle the personal data of a large number of concurrently active users. These applications must comply with complex privacy requirements, while achieving scalability and high performance. Applying constraints to the flow of data through such applications to enforce privacy policy is challenging because individual...

    Provided By Imperial College London

  • White Papers // Jan 2010

    Towards Automated Verification of Autonomous Networks: A Case Study in Self-Configuration

    In autonomic networks, the self-configuration of network entities is one of the most desirable properties. In this paper, the authors show how formal verification techniques can verify the correctness of self-configuration. As a case study, they describe the configuration of Physical Cell Identifiers (PCIs), a radio configuration parameter in cellular...

    Provided By Imperial College London

  • White Papers // May 2010

    A Decentralised, Measurement-Based Admission Control Mechanism for Self-Aware Networks

    This paper presents a decentralised Admission Control (AC) algorithm. The authors' algorithm is a multiple criteria AC algorithm, where each user can specify the QoS metrics that interest him/her, and decides whether a new call should be allowed to enter the network based on measurements of the QoS metrics on...

    Provided By Imperial College London

  • White Papers // Jun 2009

    Queueing Performance Under Network Coding

    Network Coding (NC) was initially introduced, where its utility for multicast networks was shown. NC allows the algebraic combination of packets at nodes of a multi-hop network, for example by a bit-by-bit XOR operation of two packets, before forwarding them towards their destination. NC can reduce the maximum bandwidth needed...

    Provided By Imperial College London

  • White Papers // Jan 2012

    Towards a Program Logic for JavaScript

    JavaScript has become the most widely used language for client-side web programming. The dynamic nature of JavaScript makes understanding its code notoriously difficult, leading to buggy programs and a lack of adequate static-analysis tools. The authors believe that logical reasoning has much to offer JavaScript: a simple description of program...

    Provided By Imperial College London

  • White Papers // Jun 2010

    Abstraction and Refinement for Local Reasoning

    Local reasoning has become a well-established technique in program verification, which has been shown to be useful at many different levels of abstraction. In separation logic, the authors use a low-level abstraction that is close to how the machine sees the program state. In context logic, they work with high-level...

    Provided By Imperial College London

  • White Papers // Jul 2010

    Activity Related Biometrics Based on Motion Trajectories

    This paper contributes to the concept of activity-related biometric authentication in ambient Intelligence environments. The motivation behind the proposed approach derives from activity-related biometrics and is mainly focusing on everyday activities. The activity sequence is captured by a stereoscopic camera and the resulting 2.5D data are processed to extract valuable...

    Provided By Imperial College London

  • White Papers // Sep 2009

    An Overview of Low-Power Techniques for Field-Programmable Gate Arrays

    This paper provides an overview of low-power techniques for Field-Programmable Gate Arrays (FPGAs). It covers system-level design techniques and device-level design techniques that have targeted current commercial devices. It also describes current research on circuit-level and architecture-level design techniques. Recent studies on power modelling and on low-power Computer-Aided Design (CAD)...

    Provided By Imperial College London

  • White Papers // Apr 2009

    Context-Aware Publish-Subscribe: Model, Implementation, and Evaluation

    Complex communication patterns often need to take into account the situation in which the information to be communicated is produced or consumed. Publish-subscribe, and particularly its content-based incarnation, is often used to convey this information by encoding the "Context" of the publisher into the published messages. In this paper, the...

    Provided By Imperial College London

  • White Papers // Apr 2009

    Improving Federation Executions With Migrating HLA/RTI Central Runtime Components

    Simulation tools are popular in the design and study of communication systems and networks. The implementation of analytic distributed simulations commonly requires a central entity to support certain tasks (e.g., time management). The HLA/RTI uses a Central Runtime Component (CRC) to this end. Because of network variability, the location of...

    Provided By Imperial College London

  • White Papers // Dec 2011

    Migrating Auctioneers on Internet Auctions for Improved Utility and Performance

    The paper studies a technique to improve the utility and performance of an automated auction application where the auctioneer and bidders communicate through the Internet. The lack of quality-of-service guarantees from site to site can severely influence the results of an auction by affecting the seller's income rate, auction fairness,...

    Provided By Imperial College London

  • White Papers // Mar 2012

    NaaS: Network-as-a-Service in the Cloud

    Cloud computing realises the vision of utility computing. Tenants can benefit from on-demand provisioning of computational resources according to a pay-per-use model and can outsource hardware purchases and maintenance. Tenants, however, have only limited visibility and control over network resources. Even for simple tasks, tenants must resort to inefficient overlay...

    Provided By Imperial College London

  • White Papers // Jun 2012

    Resilient Emergency Evacuation Using Opportunistic Communications

    The authors describe an emergency Evacuation Support System (ESS) that employs short-range wireless communications among mobile devices carried by civilians. Emergency information is disseminated via opportunistic contacts between Communication Nodes (CNs), and each CN provides adaptive step-by-step navigation directions for its user during evacuation. Using mobile devices and opportunistic communications...

    Provided By Imperial College London

  • White Papers // Mar 2012

    Pervasive Emergency Support Systems for Building Evacuation

    An emergency situation taking place inside a confined space, such as a building, is a challenging task due to the presence of dynamic conditions. Pervasive systems can prove beneficial for the evacuation procedure, as they can provide directions to the evacuees regarding the best available exit. In this paper, the...

    Provided By Imperial College London

  • White Papers // May 2011

    Intelligent Navigation Systems for Building Evacuation

    Intelligent navigation systems can significantly improve the evacuation of civilians in urban emergencies by providing dynamic directions to the evacuees as the hazard spreads. In this paper, the authors propose two distributed and adaptive systems for building evacuation. The first system, called Intelligent Evacuation System (IES), is composed of a...

    Provided By Imperial College London

  • White Papers // Aug 2008

    A Distributed Scheduling Algorithm With QoS Provisions in Multi-Hop Wireless Mesh Networks

    Multi-hop Wireless Mesh Networks (WMNs) are considered a promising technology to backhaul heterogeneous data traffic from wireless access networks to the wired Internet. WMNs are expected to support various types of applications with diverse Quality of Service (QoS) requirements, such as end-to-end packet delay, throughput, and Packet-Error-Rate (PER). Recent works...

    Provided By Imperial College London

  • White Papers // Jan 2009

    An Efficient Cross-Layer Simulation Architecture for Mesh Networks

    Wireless Mesh Networks (WMNs) are emerging as a promising technology for backhauling data traffic from wireless access networks to the wired Internet. Such networks are expected to support various types of applications with different Quality of Service (QoS) requirements. In this paper, the authors provide a complete cross-layer solution for...

    Provided By Imperial College London

  • White Papers // Mar 2009

    Cross-Layer Design for QoS in Wireless Mesh Networks

    Cross-layer design for Quality of Service (QoS) in Wireless Mesh Networks (WMNs) has attracted much research interest recently. Such networks are expected to support various types of applications with different and multiple QoS and Grade-of-Service (GoS) requirements. In order to achieve this, several key technologies spanning all layers, from physical...

    Provided By Imperial College London

  • White Papers // Jan 2010

    Dynamic Control of Data Ferries Under Partial Observations

    Controlled mobile helper nodes called data ferries have recently been proposed to bridge communications between disconnected nodes in a delay-tolerant manner. While existing work has explored various trajectory designs for the data ferry by assuming either static nodes or full observations at the data ferry, the problem remains open when...

    Provided By Imperial College London

  • White Papers // Jul 2009

    Connectivity Dynamics for Vehicular Ad-Hoc Networks in Signalized Road Systems

    In this paper, the authors analyze the connectivity dynamics of vehicular ad-hoc networks in a generic signalized urban route. Given the velocity profile of an urban route as a function of space and time, they utilize a fluid model to characterize the general vehicular traffic flow, and a stochastic model...

    Provided By Imperial College London