University of Cambridge

Displaying 1-40 of 251 results

  • White Papers // Dec 2013

    Security of Two-Way Quantum Key Distribution

    Quantum key distribution protocols typically make use of a one-way quantum channel to distribute a shared secret string to two distant users. However, protocols exploiting a two-way quantum channel have been proposed as an alternative route to the same goal, with the potential advantage of outperforming one-way protocols. Here, the...

    Provided By University of Cambridge

  • White Papers // Jun 2012

    Measuring the Cost of Cybercrime

    In this paper, the authors present what they believe to be the first systematic study of the costs of cybercrime. It was prepared in response to a request from the UK Ministry of Defence following scepticism that previous studies had hyped the problem. For each of the main categories of...

    Provided By University of Cambridge

  • White Papers // Jun 2012

    Error and Attack Vulnerability of Temporal Networks

    The study of real-world communication systems via complex network models has greatly expanded the people understanding on how information flows, even in completely decentralized architectures such as mobile wireless networks. Nonetheless, static network models cannot capture the time-varying aspects and, therefore, various temporal metrics have been introduced. In this paper,...

    Provided By University of Cambridge

  • White Papers // May 2012

    The Seven Deadly Sins of Cloud Computing Research

    Research into distributed parallelism on "The cloud" has surged lately. As the research agenda and methodology in this area are being established, the authors observe a tendency towards certain common simplifications and shortcuts employed by researchers, which they provocatively term "Sins". They believe that these sins, in some cases, are...

    Provided By University of Cambridge

  • White Papers // Mar 2012

    STOP: Socio-Temporal Opportunistic Patching of Short Range Mobile Malware

    Mobile phones are integral to everyday life with emails, social networking, online banking and other applications; however, the wealth of private information accessible increases economic incentives for attackers. Compared with fixed networks, mobile malware can replicate through both long range messaging and short range radio technologies; the former can be...

    Provided By University of Cambridge

  • White Papers // Feb 2012

    CHERI: A Research Platform Deconflating Hardware Virtualization and Protection

    Contemporary CPU architectures conflate virtualization and protection, imposing virtualization-related performance, programmability, and debuggability penalties on software requiring fine-grained protection. First observed in micro-kernel research, these problems are increasingly apparent in recent attempts to mitigate software vulnerabilities through application compartmentalisation. Capability Hardware Enhanced RISC Instructions (CHERI) extend RISC ISAs to support...

    Provided By University of Cambridge

  • White Papers // Jan 2012

    Physical Layer Impact Upon Packet Errors

    The authors postulate a future for optical networks where data is more susceptible to errors than has been the case to date. This paper builds upon a previous study that highlighted content-dependent error in Gigabit Ethernet. In this paper, they explain their previous non-uniformity results in terms of interactions between...

    Provided By University of Cambridge

  • White Papers // Jan 2012

    Empirical Evaluation of Hybrid Opportunistic Networks

    In this paper, the authors study the utility of opportunistic communication systems with the co-existence of network infrastructure using three real experimental deployments. They study how some important performance metrics change with varying degrees of infrastructure and mobile nodes willing to participate in the opportunistic forwarding. In doing so, they...

    Provided By University of Cambridge

  • White Papers // Jan 2012

    Distributed Multicast Grouping for Publish/Subscribe Over Mobile Ad Hoc Networks

    Event broker grids that deploy the publish/subscribe communication paradigm extend the capabilities of seamless messaging in heterogeneous network environments. In order to support such mixed network environments, the authors integrate publish/subscribe semantics with multicast routing in mobile ad hoc networks. Dynamic construction of an event dissemination structure to route events...

    Provided By University of Cambridge

  • White Papers // Oct 2011

    Evaluating Temporal Robustness of Mobile Networks

    The application of complex network models to communication systems has led to several important results: nonetheless, previous research has often neglected to take into account their temporal properties, which in many real scenarios play a pivotal role. At the same time, network robustness has come extensively under scrutiny. Understanding whether...

    Provided By University of Cambridge

  • White Papers // Aug 2011

    Opportunism Vs. Cooperation: Comparing Forwarding Strategies in Multihop Wireless Networks With Random Fading

    A wide range of forwarding strategies have been developed for multi-hop wireless networks, considering the broadcast nature of the wireless medium and the presence of random fading that results in time-varying and unreliable transmission quality. Two recently proposed strategies are opportunistic forwarding, which exploits relay diversity by opportunistically selecting an...

    Provided By University of Cambridge

  • White Papers // Jun 2011

    On the Effectiveness of an Opportunistic Traffic Management System for Vehicular Networks

    Road congestion results in a huge waste of time and productivity for millions of people. A possible way to deal with this problem is to have transportation authorities distribute traffic information to drivers, which in turn can decide (or be aided by a navigator) to route around congested areas. Such...

    Provided By University of Cambridge

  • White Papers // May 2011

    Network Clustering Via Spectral Projections

    This paper proposes a novel non-parametric technique for clustering networks based on their structure. Many topological measures have been introduced in the literature to characterize topological properties of networks. These measures provide meaningful information about the structural properties of a network, but many networks share similar values of a given...

    Provided By University of Cambridge

  • White Papers // May 2011

    Activity Based Sector Synchronisation: Efficient Transfer of Disk-State for WAN Live Migration

    Live migration of virtual machines is now commonplace but the issue of synchronising storage remains an obstacle to wide-area migration between datacentres. The authors discuss the range of possible designs for synchronising disk images and argue that they have to be adaptive at the sector level to efficiently transfer disk-state...

    Provided By University of Cambridge

  • White Papers // May 2011

    Free Lunch: Exploiting Renewable Energy for Computing

    This paper argues for "Free Lunch", a computation architecture that exploits otherwise wasted renewable energy by co-locating data-centres with these remote energy sources, connecting them over a dedicated network, and providing a software framework that supports the seamless execution and migration of virtual machines in the platform according to power...

    Provided By University of Cambridge

  • White Papers // May 2011

    The Process Of Negotiating Settlements At FERC

    Interstate gas pipelines and their customers presently settle about 90% of the rate cases set for hearing before the Federal Energy Regulatory Commission (FERC). This paper sets out the process by which this is achieved, illustrating with the 12 rate cases from 2008 and 2009. In contrast to many other...

    Provided By University of Cambridge

  • White Papers // May 2011

    Can New Nuclear Power Plants Be Project Financed?

    This paper considers the prospects for financing a wave of new Nuclear Power Plants (NPP) using project financing, which is used widely in large capital intensive infrastructure investments, including the power and gas sectors, but has not previously been used for nuclear power. It argues that the first few NPPs...

    Provided By University of Cambridge

  • White Papers // May 2011

    Security-Oriented Formal Techniques

    Security of software systems is a critical issue in a world where Information Technology is becoming more and more pervasive. The number of services for everyday life that are provided via electronic networks is rapidly increasing, as witnessed by the longer and longer list of words with the prefix "e",...

    Provided By University of Cambridge

  • White Papers // Apr 2011

    Beyond The DSGE Straightjacket

    Academic macroeconomics and the research department of central banks have come to be dominated by Dynamic, Stochastic, General Equilibrium (DSGE) models based on micro-foundations of optimising representative agents with rational expectations. The authors argue that the dominance of this particular sort of DSGE and the resistance of some in the...

    Provided By University of Cambridge

  • White Papers // Apr 2011

    On Identification Of Bayesian DSGE Models

    In recent years there has been increasing concern about the identification of parameters in Dynamic Stochastic General Equilibrium (DSGE) models. Given the structure of DSGE models it may be difficult to determine whether a parameter is identified. For the researcher using Bayesian methods, a lack of identification may not be...

    Provided By University of Cambridge

  • White Papers // Apr 2011

    The Economics Of Energy (And Electricity) Demand

    Economic drivers, technologies and demand side management are keys in understanding the long-term trends of both energy and more specifically electricity consumption. This paper discusses some of the important economics foundations of energy demand in general, and electricity in particular. First, the authors look at the macro-economic context of energy....

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Measuring User Activity on an Online Location-Based Social Network

    While in recent years online social networks have been largely shaping user experience on the Web, only in the last year there has been a soaring increase of novel location-based social applications. By allowing users to check-in at places and share their location with friends, these social platforms provide a...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Reconfigurable Data Processing for Clouds

    Reconfigurable computing for some time has had the potential to make a huge impact on mainstream high performance computing. The authors now have very large capacity FPGAs which contain many highly parallel fine grain parallel processing power, and the ability to define high bandwidth custom memory hierarchies offers a compelling...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Integrating Short-Term Demand Response Into Long-Term Investment Planning

    Planning models have been used for many years to optimize generation investments in electric power systems. More recently, these models have been extended in order to treat demand-side management on an equal footing. This paper stresses the importance of integrating short-term demand response to time-varying prices into those investment models....

    Provided By University of Cambridge

  • White Papers // Mar 2011

    War Signals: A Theory Of Trade, Trust And Conflict

    The authors construct a dynamic theory of civil conflict hinging on inter-ethnic trust and trade. The model economy is inhabitated by two ethnic groups. Inter-ethnic trade requires imperfectly observed bilateral investments and one group has to form beliefs on the average propensity to trade of the other group. Since conflict...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    CIEL: A Universal Execution Engine for Distributed Data-Flow Computing

    This paper introduces CIEL, a universal execution engine for distributed data-flow programs. Like previous execution engines, CIEL masks the complexity of distributed programming. Unlike those systems, a CIEL job can make data-dependent control-flow decisions, which enables it to compute iterative and recursive algorithms. The authors have also developed Skywriting, a...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Distributive Politics And Electoral Incentives: Evidence From Seven US State Legislatures

    The authors study the effect of electoral incentives on the allocation of public services across legislative districts. They develop a model in which elections encourage individual legislators to cater to parochial interests and thus aggravate the common pool problem. Using unique data from seven US states, they study how the...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Dynamics Of Evolution In The Global Fuel-Ethanol Industry

    The authors employ a value chain analysis approach to examine the forces shaping the industry structure, entry and inter-firm governance modes. Forty largest global and regional companies in the ethanol manufacturing stage have been classified according to their pre-entry industry of origin. Firms with pre-entry history in feedstock supply have...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Group Decision-Making: An Economic Analysis Of Social Influence And Individual Difference In Experimental Juries

    In a jury decision-making, individuals must compromise in order to reach a group consensus. If individuals compromise for non-rational reasons, such as a preference for conformity or due to erroneous information, then the final decision of the group may be biased. This paper presents original experimental data which shows that...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Strategic Eurasian Natural Gas Model For Energy Security

    The mathematical formulation of a large-scale equilibrium natural gas simulation model is presented. Although large-scale natural gas models have been developed and used for energy security and policy analysis quite extensively (e.g., Holz (2007), Egging et al. (2008), Holz et al. (2009) and Lise et al. (2008)), this model differs...

    Provided By University of Cambridge

  • White Papers // Mar 2011

    Reforming Small Power Systems Under Political Volatility: The Case Of Nepal

    This paper assesses the electricity sector reforms across small power systems while citing Nepal as an example. The on-going political instability and increasing electricity demand make power sector reform in Nepal and similar small systems a more complex process. As international reform experiences provide plenty of lessons to learn; raising...

    Provided By University of Cambridge

  • White Papers // Feb 2011

    Monetary Policy, Capital Inflows, And The Housing Boom

    The authors estimate an open economy VAR model to quantify the effect of monetary policy and capital inflows shocks on the US housing market. The shocks are identified with sign restrictions derived from a standard DSGE model. They find that monetary policy shocks have a limited effect on house prices...

    Provided By University of Cambridge

  • White Papers // Feb 2011

    Payment Matters? - An Exploratory Study Into The Pre-Payment Electricity Metering

    In this paper the authors look at the role of pre-payment (in the context of prepayment metering) for household electricity consumption. Using a matching approach, they find that households paying their electricity upfront tend to consume no less electricity than households paying ex post. This is despite facing a higher...

    Provided By University of Cambridge

  • White Papers // Feb 2011

    Liquidity Constraints And High Electricity Use

    It is a well established fact that electricity use increases with income. What is less well known is that - despite the positive correlation between electricity use and income - a significant portion of low-income households consume very large amounts of electricity. In this paper, the authors make a first...

    Provided By University of Cambridge

  • White Papers // Feb 2011

    Civil War And Human Development: Impacts Of Finance And Financial Infrastructure

    In this paper interactions between finance, development and armed conflict are explored to demonstrate that financial factors are crucial in sustaining conflict-underdevelopment feedback loops. Military expenditure drains resources, financial instability leads to conflict (and vice versa), war retards the development of financial institutions/infrastructure, and interactions between finance and conflict are...

    Provided By University of Cambridge

  • White Papers // Feb 2011

    Reforming The Power Sector In Transition: Do Institutions Matter?

    This paper quantitatively explores high-level links between power sector reforms and wider institutional reforms in the economy for a set of 27 diverse countries in rapid political and economic transition since 1990. Panel-data econometrics based on bias corrected dynamic fixed effect analysis (LSDVC) is performed to assess the impact of...

    Provided By University of Cambridge

  • White Papers // Jan 2011

    Principal Components Instrumental Variable Estimation

    Instrumental variable estimators can be severely biased in finite samples when the degree of over-identification is high or when the instruments are weakly correlated with the endogenous regressors. This paper proposes an estimator based on the use of the principal components of the instruments as a means of dealing with...

    Provided By University of Cambridge

  • White Papers // Jan 2011

    Tests For Convergence Clubs

    In many applications common in testing for convergence the number of cross-sectional units is large and the number of time periods are few. In these situations tests which are founded upon an omnibus null hypothesis are characterised by a number of problems. In this paper the authors consider a broad...

    Provided By University of Cambridge

  • White Papers // Jan 2011

    Robust Growth Determinants

    This paper investigates the robustness of determinants of economic growth in the presence of model uncertainty, parameter heterogeneity and outliers. The robust model averaging approach introduced in the paper uses a flexible and parsimonious mixture modeling that allows for fat-tailed errors compared to the normal benchmark case. Applying robust model...

    Provided By University of Cambridge

  • White Papers // Jan 2011

    Commodity Price Volatility And The Sources Of Growth

    This paper studies the impact of the level and volatility of commodity terms of trade on economic growth, as well as on the three main growth channels: Total factor productivity, physical capital accumulation, and human capital acquisition. The authors argue that volatility, rather than abundance per se, drives the "Resource...

    Provided By University of Cambridge

  • White Papers // Jan 2010

    Profiling Sprints Using On-Body Sensors

    This paper describes the design, implementation and deployment of a wireless sensor system for athletes. The system is designed to profile sprints based on input from on-body sensors that are wirelessly connected to a nearby infrastructure. The authors discuss the choice and use of inexpensive Force Sensitive Resistors (FSRs) to...

    Provided By University of Cambridge

  • White Papers // Nov 2009

    Can Frequency Diversity Provide Performance Gains for WSNs at 2.4GHz for the Fire Hydrant to Above Ground Channel

    Wireless Sensor Networks (WSNs) which utilize IEEE 802.15.4 technology offer the potential for low cost deployment and maintenance compared with conventional wired sensor networks, enabling effective and efficient condition monitoring of aged civil engineering infrastructure. The authors will address wireless propagation for a below to above ground scenario where one...

    Provided By University of Cambridge

  • White Papers // Jul 2009

    Randomly Select and Forward: Erasure Probability Analysis of a Probabilistic Relay Channel Model

    This paper proposes a semi-analytical framework for estimating the erasure probability in single-hop multi-relay networks. Specifically, the authors consider a system, in which relays do not decode the information but simply forward coded packets that have been previously received from the source. This allows for uncoordinated, low-complexity processing at the...

    Provided By University of Cambridge

  • White Papers // Aug 2009

    Evaluation of Multi-Carrier Burst Contention and IEEE 802.11 With Fading During Channel Sensing

    With the prevalence of wireless capability in mobile devices and the increasing number of wireless network deployments where protocols using carrier sensing (such as IEEE 802.11) are employed, it is important to understand the impact of fading during the channel sensing period and its direct effects on performance in realistic...

    Provided By University of Cambridge

  • White Papers // Nov 2009

    Frequency Diversity Measurements at 2.4 GHz for Wireless Sensor Networks Deployed in Tunnels

    Wireless Sensor Networks (WSNs) which utilize IEEE 802.15.4 technology operate primarily in the 2.4 GHz globally compatible ISM band. However, the wireless propagation channel in this crowded band is notoriously variable and unpredictable, and it has a significant impact on the coverage range and quality of the radio links between...

    Provided By University of Cambridge

  • White Papers // Apr 2009

    Packet Error Probability for Decode-and-Forward Cooperative Networks of Selfish Users

    In this paper, the authors consider cooperative networks of users that implement a selfish protocol to decode and forward packets of their partners. They use a threshold-based model to derive an analytical expression for the end-to-end packet error probability and they validate their approach comparing theoretical to simulation results. Furthermore,...

    Provided By University of Cambridge

  • White Papers // Apr 2009

    Performance Analysis and Adaptive Power Control for Block Coded Collaborative Networks

    The authors derive theoretical bit and frame error rate expressions for Decode-and-Forward (DF) collaborative networks containing M users, employing a variety of block codes over a Rayleigh block faded channel. With the aid of these expressions, they explore the performance of adaptive power control for such systems. This extends previous...

    Provided By University of Cambridge

  • White Papers // Jan 2009

    Threshold-Based Frame Error Rate Analysis of MIMO Systems Over Quasi-Static Fading Channels

    Proper selection of a Signal-to-Noise Ratio (SNR) threshold largely determines the tightness of an approximation to the frame error rate of a system over a quasi-static fading channel. The authors demonstrate that the expression for the optimal threshold value, which has been established for Single-Input Single-Output (SISO) channels, remains unchanged...

    Provided By University of Cambridge

  • White Papers // Aug 2008

    Investigation of Close-to-Wall Wireless Sensor Deployment Using 2d Finite-Difference Time-Domain Modelling

    When Wireless Sensor Networks (WSNs) are deployed in a railway tunnel environment, the available deployment positions and equipment size are restricted by regulations from the infrastructure owners in order to maintain the loading gauge. As the authors have discovered in the Aldwych tunnel, antennas mounted near to the tunnel wall...

    Provided By University of Cambridge

  • White Papers // Oct 2011

    Evaluating Temporal Robustness of Mobile Networks

    The application of complex network models to communication systems has led to several important results: nonetheless, previous research has often neglected to take into account their temporal properties, which in many real scenarios play a pivotal role. At the same time, network robustness has come extensively under scrutiny. Understanding whether...

    Provided By University of Cambridge

  • White Papers // Jun 2011

    On the Effectiveness of an Opportunistic Traffic Management System for Vehicular Networks

    Road congestion results in a huge waste of time and productivity for millions of people. A possible way to deal with this problem is to have transportation authorities distribute traffic information to drivers, which in turn can decide (or be aided by a navigator) to route around congested areas. Such...

    Provided By University of Cambridge

  • White Papers // Jun 2009

    Finding a Data Blackhole in Bluetooth Scanning

    Bluetooth scanning has now been widely used in different scenarios to study users' mobility and their underlying social network. However, scanning for Bluetooth enabled devices does not always detect all the devices in range, mainly because of interference and obstacles. The authors are interested in quantifying the number of missed...

    Provided By University of Cambridge

  • White Papers // Oct 2010

    Distributed Middleware Enforcement of Event Flow Security Policy

    Distributed, event-driven applications that process sensitive user data and involve multiple organisational domains must comply with complex security requirements. Ideally, developers want to express security policy for such applications in data-centric terms, controlling the flow of information throughout the system. Current middleware does not support the specification of such end-to-end...

    Provided By University of Cambridge

  • White Papers // Oct 2010

    Policy Generation Framework for Large-Scale Storage Infrastructures

    Cloud computing is gaining acceptance among mainstream technology users. Storage cloud providers often employ Storage Area Networks (SANs) to provide elasticity, rapid adaptability to changing demands, and policy based automation. As storage capacity grows, the storage environment becomes heterogeneous, increasingly complex, harder to manage, and more expensive to operate. This...

    Provided By University of Cambridge

  • White Papers // Jul 2008

    Autonomic QoS Control in Enterprise Grid Environments Using Online Simulation

    As Grid Computing increasingly enters the commercial domain, performance and Quality of Service (QoS) issues are becoming a major concern. The inherent complexity, heterogeneity and dynamics of Grid computing environments pose some challenges in managing their capacity to ensure that QoS requirements are continuously met. In this paper, a comprehensive...

    Provided By University of Cambridge

  • White Papers // Apr 2010

    Dynamically Checking Ownership Policies in Concurrent C/C++ Programs

    Concurrent programming errors arise when threads share data incorrectly. Programmers often avoid these errors by using synchronization to enforce a simple ownership policy: data is either owned exclusively by a thread that can read or write the data, or it is read owned by a set of threads that can...

    Provided By University of Cambridge

  • White Papers // Mar 2010

    Verifying Generics and Delegates

    Recently, object-oriented languages, such as C#, have been extended with language features prevalent in most functional languages: parametric polymorphism and higher-order functions. In the OO world these are called generics and delegates, respectively. These features allow for greater code reuse and reduce the possibilities for run-time errors. However, the combination...

    Provided By University of Cambridge

  • White Papers // Jul 2008

    Security Across Disparate Management Domains in MANETs

    Creating a division between inter-domain and intra-domain routing is expected to assist in meeting the challenges of future MANET deployments in terms of heterogeneity and administrative separation. Previous research in MANET routing and security has focused on the intra-domain context. This paper discusses the problems encountered in inter-domain routing security,...

    Provided By University of Cambridge

  • White Papers // Dec 2009

    Green Wave: Latency and Capacity-Efficient Sleep Scheduling for Wireless Networks

    Sleep scheduling of wireless transceivers has been established to be critical for the enhancement of operational lifetimes of wireless networks. By carefully designing sleep schedules, this paper shows how the latency and capacity of sleep-scheduling wireless networks can be achieved up to their respective optimal scaling laws. Although the general...

    Provided By University of Cambridge

  • White Papers // Jul 2009

    Topology-Aware Inter-Domain Routing for Heterogeneous MANETs

    With ever increasing number of diverse routing protocols proposed to deal with network dynamics in MANETs, the heterogeneity of MANETs has increased dramatically. While many of these proposals only concern enhancing routing in a single domain, little attention has been given to the interoperations among the heterogeneous MANETs. Moreover, the...

    Provided By University of Cambridge

  • White Papers // Nov 2010

    SpotME if You Can: Randomized Responses for Location Obfuscation on Mobile Phones

    Nowadays companies increasingly aggregate location data from different sources on the Internet to offer location-based services such as estimating current road traffic conditions, and finding the best nightlife locations in a city. However, these services have also caused outcries over privacy issues. As the volume of location data being aggregated...

    Provided By University of Cambridge

  • White Papers // Jul 2010

    Energy-Accuracy Trade-Offs in Querying Sensor Data for Continuous Sensing Mobile Systems

    A large number of context-inference applications run on off-the-shelf smart-phones and infer context from the data acquired by means of the sensors embedded in these devices. The use of efficient and effective sampling technique is of key importance for these applications. Aggressive sampling can ensure a more fine-grained and accurate...

    Provided By University of Cambridge

  • White Papers // Dec 2009

    Scientific Computing Environments in the Age of Virtualization

    This paper describes Biocep-R, an Open Source platform for the virtualization of Scientific Computing Environments (SCEs) such as R and Scilab. To the authors' knowledge it is the first time that a software platform enables geographically distributed collaborators to view and analyze terabytes of data interactively and collaboratively, using standard...

    Provided By University of Cambridge

  • White Papers // Dec 2009

    Extending Access Point Connectivity Through Opportunistic Routing in Vehicular Networks

    Nowadays, the navigation systems available on cars are becoming more and more sophisticated. They greatly improve the experience of drivers and passengers by enabling them to receive map and traffic updates, news feeds, advertisements, media files, etc. Unfortunately, the bandwidth available to each vehicle with the current technology is severely...

    Provided By University of Cambridge

  • White Papers // Oct 2008

    Social Security As A Developmental Institution? Extending The Solar Case For The Relative Efficacy Of Poor Relief Provisions Under The English Old Poor Law

    This paper assesses various issues concerning the operation of the English Old Poor from 1600 to 1834 that are presented as facilitating economic growth. It identifies those factors contributing to the efficacy of welfare provisioning by reference to problems that are frequently identified in the operation of such systems: the...

    Provided By University of Cambridge

  • White Papers // Dec 2008

    Vintage And Credit Rating: What Matters In The ABX Data During The Credit Crunch?

    The mortgage backed securities market has dramatically declined during the credit crunch of 2007-2008. To understand the factors driving its demise the authors utilise a latent factor model representing common effects, asset rating effects, vintage of issuance effects and liquidity effects - extending the recent representation of CDO pricing in...

    Provided By University of Cambridge

  • White Papers // Oct 2010

    Interoperability in a Scripted World: Putting Inheritance & Prototypes Together

    Scripting languages are used to quickly and easily develop or extend programs. Frequently, these scripted programs are combined with libraries and other programs from conventional languages to build more complex applications. Bridging the gap between different languages requires manual data conversions and dynamic checks which can introduce subtle errors. Language...

    Provided By University of Cambridge

  • White Papers // May 2011

    Free Lunch: Exploiting Renewable Energy for Computing

    This paper argues for "Free Lunch", a computation architecture that exploits otherwise wasted renewable energy by co-locating data-centres with these remote energy sources, connecting them over a dedicated network, and providing a software framework that supports the seamless execution and migration of virtual machines in the platform according to power...

    Provided By University of Cambridge

  • White Papers // Feb 2012

    CHERI: A Research Platform Deconflating Hardware Virtualization and Protection

    Contemporary CPU architectures conflate virtualization and protection, imposing virtualization-related performance, programmability, and debuggability penalties on software requiring fine-grained protection. First observed in micro-kernel research, these problems are increasingly apparent in recent attempts to mitigate software vulnerabilities through application compartmentalisation. Capability Hardware Enhanced RISC Instructions (CHERI) extend RISC ISAs to support...

    Provided By University of Cambridge

  • White Papers // May 2010

    Using Dust Clouds to Enhance Anonymous Communication

    Cloud computing platforms, such as Amazon EC2, enable customers to lease several Virtual Machines (VMs) on a per-hour basis. The customer can now obtain a dynamic and diverse collection of machines spread across the world. In this paper, the authors consider how this aspect of cloud computing can facilitate anonymous...

    Provided By University of Cambridge

  • White Papers // May 2011

    Network Clustering Via Spectral Projections

    This paper proposes a novel non-parametric technique for clustering networks based on their structure. Many topological measures have been introduced in the literature to characterize topological properties of networks. These measures provide meaningful information about the structural properties of a network, but many networks share similar values of a given...

    Provided By University of Cambridge

  • White Papers // Feb 2010

    Nomadic Pict: Programming Languages, Communication Infrastructure Overlays, and Semantics for Mobile Computation

    Mobile computation, in which executing computations can move from one physical computing device to another, is a recurring theme: from OS process migration, to language-level mobility, to virtual machine migration. This paper reports on the design, implementation, and verification of overlay networks to support reliable communication between migrating computations, in...

    Provided By University of Cambridge

  • White Papers // Jun 2009

    Tracking Elephant Flows in Internet Backbone Traffic with an FPGA-Based Cache

    This paper presents an FPGA-friendly approach to tracking elephant flows in network traffic. The authors' approach, Single Step Segmented Least Recently Used (S3-LRU) policy, is a network traffic-friendly replacement policy for maintaining flow states in a Nayve Hash Table (NHT). They demonstrate that their S3-LRU approach preserves elephant flows: conservatively...

    Provided By University of Cambridge

  • White Papers // Feb 2009

    GTVS: Boosting the Collection of Application Traffic Ground Truth

    Interesting research in the areas of traffic classification, network monitoring, and application-oriented analysis can not proceed without real traffic traces, labeled with actual application information. However, hand-labeled traces are an extremely valuable but scarce resource in the traffic monitoring and analysis community, as a result of both privacy concerns and...

    Provided By University of Cambridge

  • White Papers // Oct 2008

    Efficient Application Identification and the Temporal and Spatial Stability of Classification Schema

    Motivated by the importance of accurate identification for a range of applications, this paper compares and contrasts the effective and efficient classification of network-based applications using behavioral observations of network-traffic and those using Deep-Packet Inspection. Importantly, throughout the authors' paper, they are able to make comparison with data possessing an...

    Provided By University of Cambridge

  • White Papers // Jan 2012

    Physical Layer Impact Upon Packet Errors

    The authors postulate a future for optical networks where data is more susceptible to errors than has been the case to date. This paper builds upon a previous study that highlighted content-dependent error in Gigabit Ethernet. In this paper, they explain their previous non-uniformity results in terms of interactions between...

    Provided By University of Cambridge

  • White Papers // Mar 2010

    On the Security of Internet Banking in South Korea

    South Korean Internet banking systems have a unique way of enforcing security controls. Users are obliged to install proprietary security software - typically an ActiveX plugin that implements a bundle of protection mechanisms in the user's browser. The banks and their software suppliers claim that this provides trustworthy user platforms....

    Provided By University of Cambridge

  • White Papers // Dec 2008

    Identifying Social Communities in Complex Communications for Network Efficiency

    Complex communication networks, more particular Mobile Ad Hoc NETworks (MANET) and Pocket Switched Networks (PSN), rely on short range radio and device mobility to transfer data across the network. These kind of mobile networks contain duality in nature: they are radio networks at the same time also human networks, and...

    Provided By University of Cambridge

  • White Papers // May 2011

    Activity Based Sector Synchronisation: Efficient Transfer of Disk-State for WAN Live Migration

    Live migration of virtual machines is now commonplace but the issue of synchronising storage remains an obstacle to wide-area migration between datacentres. The authors discuss the range of possible designs for synchronising disk images and argue that they have to be adaptive at the sector level to efficiently transfer disk-state...

    Provided By University of Cambridge

  • White Papers // Sep 2008

    Applying Policy to Inter-Domain MANET Routing in Challenging Environments

    MANETs operate within a considerably more dynamic environment than traditional fixed network inter-domain routing is designed to handle, as MANETs are wireless networks with rapidly changing topologies. Inter-Domain Routing for MANETs (IDRM) aims to provide a solution to manage dynamic topology changes, but the impact of this on network resource...

    Provided By University of Cambridge