Norwegian University of Science and Technology

Displaying 1-40 of 91 results

  • White Papers // Dec 2013

    A Metadata Extraction Approach for Selecting Migration Solutions

    Preservation becomes an important infrastructural service for information systems. Many research works have done in past decades. The most popular preservation approach is migration, which transfers and/or transforms digital objects between two computers or two generations of computer technology. However, it is difficult for custodians to decide which migration solution...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2012

    Locating Disruptions on Internet Paths Through End-to-End Measurements

    In backbone networks carrying heavy traffic loads, unwanted and unusual end-to-end delay changes can happen, though possibly rarely. In order to understand and manage the network to potentially avoid such abrupt changes, it is crucial and challenging to locate where in the network lies the cause of such delays so...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jun 2012

    The Multivariate Probabilistic Encryption Scheme MQQ-ENC

    The authors propose a new multivariate probabilistic encryption scheme with decryption errors MQQ-ENC that belongs to the family of MQQ-based public key schemes. Similarly to MQQ-SIG, the trapdoor is constructed using quasigroup string transformations with multivariate quadratic quasigroups, and a minus modifier with relatively small and fixed number of removed...

    Provided By Norwegian University of Science and Technology

  • White Papers // May 2012

    Cost Comparison of 1+1 Path Protection Schemes: A Case for Coding

    Communication networks have to provide a high level of resilience in order to ensure sufficient Quality of Service for mission-critical services. Currently, dedicated 1+1 path protection is implemented in backbone networks to provide the necessary resilience. On the other hand, there are several possible realization strategies for 1+1 path protection...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2012

    Computational Security Analysis of the UMTS and LTE Authentication and Key Agreement Protocols

    One of the forerunners and main candidates for the Fourth Generation (4G) generation mobile communication system is commonly known under the name Long-Term Evolution (LTE) and its standard is produced and maintained by the international 3rd Generation Partnership Program (3GPP) consortium. The LTE Authentication and Key Agreement (AKA) protocol design...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2012

    Maximizing the Throughput Guarantees in Wireless Networks Under Imperfect Channel Knowledge

    In the authors' earlier work, they described an optimization problem and corresponding scheduling algorithm aimed at obtaining maximum throughput guarantees in wireless networks. To further improve the short-term performance, they also proposed two adaptive versions of the optimal algorithm. Results from the simulations showed that the adaptive algorithms perform significantly...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2012

    Scheduling Techniques in an Integrated Hybrid Node With Electronic Buffers

    Integrated hybrid optical packet/circuit switched architectures enable networks with the Guaranteed Service Transport (GST) of circuit switching and the statistical multiplexing known from packet switching. The utilization of the optical light-paths is increased by inserting low priority Statistically Multiplexed (SM) traffic in the guaranteed circuit switched traffic gaps. Previous studies...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2012

    Collaboration for Enhancing the System Development Process in Open Source Diligence

    According to different opponents and commercial giants in software industries, the open source style software development has enough capacity to complete successfully the large scale projects. But the authors have seen many flaws and loops in collaboration and handling of mega scale projects in open source environment. Perhaps the collaboration...

    Provided By Norwegian University of Science and Technology

  • White Papers // Dec 2011

    Smart Grid Software Applications as an Ultra-Large-Scale System: Challenges for Evolution

    Software applications play a major role to support the smartness in Smart Grid. Such applications are in a never-ending state of flux due to rapidly changing expectations from the users and stakeholders. Hence, evolution is an important matter for development of Smart Grid software applications and the challenging factors of...

    Provided By Norwegian University of Science and Technology

  • White Papers // Nov 2011

    A Multi-Factor Security Protocol for Wireless Payment - Secure Web Authentication Using Mobile Devices

    Previous Web access authentication systems often use either the Web or the Mobile channel individually to confirm the claimed identity of the remote user. This paper proposes a new protocol using multifactor authentication system that is both secure and highly usable. It uses a novel approach based on Transaction Identification...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2011

    Performance of Multiuser CDMA Receivers With Bursty Traffic and Delay Constraints

    In this paper, the authors analyze the performance of linear multiuser CDMA receivers under bursty traffic and queuing delay constraints. An ON/OFF source is used to model the traffic burstiness and stochastic network calculus incorporates the queuing delay constraints in the analysis. At the physical layer, adaptive modulation and coding...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2011

    Stochastic Network Calculus for Performance Analysis of Internet Networks - An Overview and Outlook

    Stochastic network calculus is a theory for performance guarantee analysis of Internet networks. Originated in early 1990s, stochastic network calculus has its foundation on the min-plus convolution and max-plus convolution queueing principles. Although challenging, it has shown tremendous potential in dealing with queueing type problems encountered in Internet networks. By...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2011

    Cache-Aware Matrix Multiplication on Multicore Systems for IPM-Based LP Solvers

    The authors profile GLPK, an open source linear programming solver, and show empirically that the form of matrix multiplication used in interior point methods takes a significant portion of the total execution time when solving some of the Netlib and other LP data sets. Then, they discuss the drawbacks of...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2011

    Metric-based Similarity Search in Unstructured Peer-to-Peer Systems

    Peer-To-Peer systems constitute a promising solution for deploying novel applications, such as distributed image retrieval. Efficient search over widely distributed multimedia content requires techniques for distributed retrieval based on generic metric distance functions. In this paper, the authors propose a framework for distributed metric-based similarity search, where each participating peer...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2011

    Multi-Service Load Balancing in a Heterogeneous Network With Vertical Handover

    In this paper, the authors investigate multi-service load balancing mechanisms in an overlay heterogeneous WiMAX/WLAN network through vertical handover. Considering the service characteristics of the overlay heterogeneous network together with the service requirements of different applications, all streaming applications are served in WiMAX while elastic applications are distributed to WiMAX...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2011

    E-Collaboration for Maritime Operations using Business Process Modeling

    One of the highly globalized fields such as Marine Industry, shipping operations are hugely dependent on e-collaboration tools that holds potential to provide quick and readily accessible information across ports, organizations and people across nations concerned with industry. Improving operational efficiency is very much dependent on business process transformation by...

    Provided By Norwegian University of Science and Technology

  • White Papers // Aug 2011

    Timing Failures Caused by Resource Starvation in Virtual Machinesa

    This paper discusses cascading effects of resource starvation in virtual machines, and how that affects end-user experiences in certain cases. The paper presents the occurring issues on an N-tier server system, and the way the starvation causes unexpected delays in a service for an end-user. The initial observations were on...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jun 2011

    Approximate Fairness Through Limited Flow List

    Most of router mechanisms proposed for fair bandwidth sharing lack either simplicity due to complexity of intricate per flow management of all connections (e.g., WFQ, SFQ), heterogeneity due to a design targeting a specific traffic type, e.g., RED-PD and Fair RED (FRED) or robustness due to requirement for proper router...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2011

    Multi-Service Load Balancing in a Heterogeneous Network

    In this paper, the authors investigate load balancing mechanisms in heterogeneous WiMAX/WLAN network. By taking both the service characteristics of the two networks and service requirements of two kinds of applications into consideration, they distribute all streaming applications to WiMAX with preemptive service priority. Then the remaining capacities of WiMAX...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2011

    Delay Constrained Throughput Analysis of a Correlated MIMO Wireless Channel

    The maximum traffic arrival rate at the network for a given delay guarantee (delay constrained throughput) has been well studied for wired channels. However, few results are available for wireless channels, especially when multiple antennas are employed at the transmitter and receiver. In this work, the authors analyze the network...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    Vector Precoding for Gaussian MIMO Broadcast Channels: Impact of Replica Symmetry Breaking

    The so-called "Replica method" of statistical physics is employed for the large system analysis of vector precoding for the Gaussian Multiple-Input Multiple-Output (MIMO) broadcast channel. The transmitter is assumed to comprise a linear front-end combined with nonlinear precoding, that minimizes the front-end imposed transmit energy penalty. Focusing on discrete complex...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    A Structural Analysis of Network Delay

    Network delay is a crucial metric for evaluating the state of the network. The authors present in this paper a structural analysis of network delay, based on delay measurements of a backbone network. This delay analysis is performed using a subspace method called Principal Component Analysis (PCA). The analysis reveals...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    A Survey on Random Number Generators(RNG) for Cryptographic Application

    Random numbers are used in different purposes, such as sampling from a large data set, simulating and modeling a complex phenomena. It also plays a very important role in information security and cryptography. Random numbers are used for PIN, password, creating cryptographic keys and challenges for authentication etc. When discussing...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    Maximizing Network Revenue Through Resource Management in Heterogeneous Wireless Networks

    Several radio access technologies are now likely to coexist in the same area, and form the so-called heterogeneous wireless networks. In this paper, the authors study the coordination between WiMAX and WiFi through Radio Resource Management (RRM) in order to maximize the network operator's revenue. Two solutions for the optimization...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    DYFRAM: Dynamic Fragmentation and Replica Management in Distributed Database Systems

    In distributed database systems, tables are frequently fragmented and replicated over a number of sites in order to reduce network communication costs. How to fragment, when to replicate and how to allocate the fragments to the sites are challenging problems that has previously been solved either by static fragmentation, replication...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    Accumulation Of Education And Regional Income Growth: Limited Human Capital Effects In Norway

    Accumulation of education and geographic concentration of educated people in cities are expected to generate urban income growth. New economic geography predicts income divergence across regions. The authors investigate the dynamic process of accumulating tertiary education and regional income growth in Norway during the past four decades. The expansion of...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    Migration And Dynamic Agglomeration Economies: Regional Income Growth In Norway

    The existence of agglomeration economies is well established. The authors study dynamic agglomeration effects and expect regional income divergence when people move from the periphery to cities. They use distribution analysis, Kernel density functions and first order Markov chains, to investigate whether data from Norwegian regions 1972-2008 with strong urbanization...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    A Virtual Queue Approach to Loss Estimation

    In network quality of service provisioning, small loss probabilities are often required. Such loss probabilities are so small that they may hardly be measured on line directly. In this paper, an indirect Virtual Queue (VQ) approach is proposed for loss estimation. The idea of the proposed approach is to use...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    A Measurement Allocation Scheme for Reliable Data Gathering in Spatially Correlated Sensor Networks

    In this paper, the authors consider the measurement allocation problem in a spatially correlated sensor field. Their goal is to determine the probability of each sensor's being measured based on its contribution to the estimation reliability; it is desirable that a sensor improving the estimation reliability is measured more frequently....

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    How Globalization Of Media And Civil Society Are Affecting Contentious Politics

    The globalization of mass media and civil society is creating new resources for political contention. Drawing on a theory of the role of third parties in different forms of contentious politics, the authors argue that the effects of these new resources should be greatest for protest and terrorist attacks, somewhat...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    Efficient Distributed Top-k Query Processing With Caching

    Recently, there has been an increased interest in incorporating in database management systems rank-aware query operators, such as top-k queries, that allow users to retrieve only the most interesting data objects. In this paper, the authors propose a cache-based approach for efficiently supporting top-k queries in distributed database management systems....

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    Logic-BasedWeb Services Composition: From Service Description to Process Model

    This paper introduces a method for automatic composition of Semantic Web services using Linear Logic (LL) theorem proving. The method uses Semantic Web service language (DAML-S) for external presentation of Web services, while, internally, the services are presented by extralogical axioms and proofs in LL. The authors use a process...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    Energy-Optimised Coded Modulation for Short-Range Wireless Communications on Nakagami-M Fading Channels

    When the distance between the transmitter and the receiver of a wireless communication link is sufficiently short, circuit energy consumption and transmission energy consumption become comparable, and substantial energy savings can be achieved by making use of a transmission scheme which takes into account total energy consumption instead of transmission...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    Fairness-Enhanced Multiple Control Channels MAC for Ad Hoc Networks

    The throughput in IEEE 802.11 ad hoc networks can be improved by exploiting the presence of multiple channels and thus allowing multiple nodes to transmit concurrently on different channels. This has been shown by previous work. Some multi-channel MAC protocols use one control channel for exchanging control messages in order...

    Provided By Norwegian University of Science and Technology

  • White Papers // Dec 2010

    The Digital Signature Scheme MQQ-SIG

    The authors the seven names given in the title of this paper and undersigned on this statement, the authors and designers of MQQ-SIG digital signature scheme, do hereby agree to grant any interested party an irrevocable, royalty free licence to practice, implement and use MQQ-SIG digital signature scheme, provided the...

    Provided By Norwegian University of Science and Technology

  • White Papers // Dec 2010

    Iterative MMSE Receivers for Multiuser MIMO Cooperative Systems

    In this paper, the authors study a two-user multiple antenna system under quasi-static fading employing a novel scheme that combines cooperation and iterative multiuser detection based on minimum mean square error estimation. They investigate three different receivers: a joint detector for the two users, a separate (per-user) detector, and a...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2010

    Performance Bounds for a Cognitive Radio Network With Network Calculus Analysis

    In this paper, the authors use stochastic network calculus to analyze the performance bounds for a cognitive radio network with two classes of input traffic. First, stochastic service curves for primary users and secondary users are obtained based on the system model and stochastic network calculus. Then, they derive the...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2010

    Evaluating the Information Efficiency of Multi-Hop Networks With Carrier Sensing Capability

    In this contribution, the authors consider the performance of the CSMA MAC protocol in multi-hop ad hoc networks in terms of "Aggregate multi-hop information efficiency". The authors' model consists of a wireless network where transmitter nodes are distributed according to a homogeneous 2-D Poisson point process, and packets are generated...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2010

    On the Flow-Level Delay of a Spatial Multiplexing MIMO Wireless Channel

    The MIMO wireless channel offers a rich ground for quality of service analysis. In this paper, the authors present a stochastic network calculus analysis of a MIMO system, operating in spatial multiplexing mode, using Moment Generating Functions (MGF). They quantify the spatial multiplexing gain, achieved through multiple antennas, for flow...

    Provided By Norwegian University of Science and Technology

  • White Papers // Aug 2010

    Fundamentals of the Backoff Process in 802.11: Dichotomy of the Aggregation

    Since its introduction, the performance of IEEE 802.11 has attracted a lot of research attention and the center of the attention has been the throughput. Recently, other critical performance aspects of 802.11 also burst onto the scene, which include short-term fairness and delay. It goes without saying that there has...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jun 2012

    The Multivariate Probabilistic Encryption Scheme MQQ-ENC

    The authors propose a new multivariate probabilistic encryption scheme with decryption errors MQQ-ENC that belongs to the family of MQQ-based public key schemes. Similarly to MQQ-SIG, the trapdoor is constructed using quasigroup string transformations with multivariate quadratic quasigroups, and a minus modifier with relatively small and fixed number of removed...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2009

    Reflected Simplex Codebooks for Limited Feedback MIMO Beamforming

    A simple technique to obtain the highest possible diversity order in Multiple-Input Multiple-Output (MIMO) wireless links is to employ transmit beamforming and receive combining, which simultaneously improves the array gain. This technique requires that the transmitter has channel state information in the form of a transmit beamforming vector. It is...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2012

    Scheduling Techniques in an Integrated Hybrid Node With Electronic Buffers

    Integrated hybrid optical packet/circuit switched architectures enable networks with the Guaranteed Service Transport (GST) of circuit switching and the statistical multiplexing known from packet switching. The utilization of the optical light-paths is increased by inserting low priority Statistically Multiplexed (SM) traffic in the guaranteed circuit switched traffic gaps. Previous studies...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2011

    Metric-based Similarity Search in Unstructured Peer-to-Peer Systems

    Peer-To-Peer systems constitute a promising solution for deploying novel applications, such as distributed image retrieval. Efficient search over widely distributed multimedia content requires techniques for distributed retrieval based on generic metric distance functions. In this paper, the authors propose a framework for distributed metric-based similarity search, where each participating peer...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jul 2010

    A Hybrid Approach for Estimating Document Frequencies in Unstructured P2P Networks

    Scalable search and retrieval over numerous web document collections distributed across different sites can be achieved by adopting a Peer-To-Peer (P2P) communication model. Terms and their document frequencies are the main components of text information retrieval and as such need to be computed, aggregated, and distributed throughout the system. This...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jul 2009

    Aggregation of Document Frequencies in Unstructured P2P Networks

    Peer-To-Peer (P2P) systems have been recently proposed for providing search and information retrieval facilities over distributed data sources, including web data. Terms and their document frequencies are the main building blocks of retrieval and as such need to be computed, aggregated, and distributed throughout the system. This is a tedious...

    Provided By Norwegian University of Science and Technology

  • White Papers // Dec 2011

    Smart Grid Software Applications as an Ultra-Large-Scale System: Challenges for Evolution

    Software applications play a major role to support the smartness in Smart Grid. Such applications are in a never-ending state of flux due to rapidly changing expectations from the users and stakeholders. Hence, evolution is an important matter for development of Smart Grid software applications and the challenging factors of...

    Provided By Norwegian University of Science and Technology

  • White Papers // Aug 2011

    Timing Failures Caused by Resource Starvation in Virtual Machinesa

    This paper discusses cascading effects of resource starvation in virtual machines, and how that affects end-user experiences in certain cases. The paper presents the occurring issues on an N-tier server system, and the way the starvation causes unexpected delays in a service for an end-user. The initial observations were on...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2008

    Business Domain Models in ERP Development

    Business domain models play an important role in the context of ERP systems implementations, where e.g. industry specific reference models are used to set up the ERP systems at the end user organizations. In this paper, the authors will focus on another, less researched, part of ERP software practice where...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2011

    E-Collaboration for Maritime Operations using Business Process Modeling

    One of the highly globalized fields such as Marine Industry, shipping operations are hugely dependent on e-collaboration tools that holds potential to provide quick and readily accessible information across ports, organizations and people across nations concerned with industry. Improving operational efficiency is very much dependent on business process transformation by...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2008

    Secure Socket SCTP: A Multi-Layer End-to-End Security Solution

    Stream Control Transmission Protocol (SCTP) is a rather new full-fledged transport protocol with a rich set of functionalities. In SCTP, transport layer multi-homing for enhanced network fault tolerance is provided. The concept of multi-streaming is also included to reduce the impact of head-of-line blocking of unrelated data. In addition, enhanced...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2010

    Data Hiding Techniques Using Prime and Natural Numbers

    In this paper, a few novel data hiding techniques are proposed. These techniques are improvements over the classical LSB data hiding technique and the Fibonacci LSB data-hiding technique proposed by Battisti et al. The classical LSB technique is the simplest, but using this technique it is possible to embed only...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2006

    On Stochastic Modeling for Integrated Security and Dependability Evaluation

    In this paper, the authors present a new approach to integrated security and dependability evaluation, which is based on stochastic modeling techniques. Their proposal aims to provide operational measures of the trustworthiness of a system, regardless if the underlying failure cause is intentional or not. By viewing system states as...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2009

    Edon-R, An Infinite Family of Cryptographic Hash Functions

    Cryptographic hash functions are used in a wide range of applications including message integrity, authentication, digital signature and public key encryption. A cryptographic hash function takes an input of arbitrary size and produces an output, also called the hash value, of a fixed, predetermined size. The important properties of a...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2009

    On a Family of Minimal Candidate One-Way Functions and One-Way Permutations

    The concept of one-way function is the fundamental concept in the modern cryptography and was first introduced by Diffie and Hellman in their seminal paper. Since then, many designed cryptographic primitives that claim that are cryptographically strong, actually suppose that they have implemented the concept of one-wayness in some proper...

    Provided By Norwegian University of Science and Technology

  • White Papers // Dec 2013

    A Metadata Extraction Approach for Selecting Migration Solutions

    Preservation becomes an important infrastructural service for information systems. Many research works have done in past decades. The most popular preservation approach is migration, which transfers and/or transforms digital objects between two computers or two generations of computer technology. However, it is difficult for custodians to decide which migration solution...

    Provided By Norwegian University of Science and Technology

  • White Papers // Apr 2009

    A Quantitative Study of Memory System Interference in Chip Multiprocessor Architectures

    The potential for destructive interference between running processes is increased as Chip Multi-Processors (CMPs) share more on-chip resources. The authors believe that understanding the nature of memory system interference is vital to achieve good fairness/complexity/performance trade-offs in CMPs. Their goal in this work is to quantify the latency penalties due...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2007

    Performance Effects of a Cache Miss Handling Architecture in a Multi-core Processor

    Multi-core processors, also called Chip Multi-Processors (CMPs), have recently been proposed to counter several of the problems associated with modern superscalar microprocessors: limited Instruction Level Parallelism (ILP), high power consumption and large design complexity. However, the performance gap between a processor core and main memory is large and growing. Consequently,...

    Provided By Norwegian University of Science and Technology

  • White Papers // Apr 2008

    Scheduling in Multiprocessor System Using Genetic Algorithms

    Real-time systems are software systems in which the time at which the result is produced is as important as the logical correctness of the result. Multiprocessors have emerged as a powerful computing means for running real-time applications, especially where a uniprocessor system would not be sufficient enough to execute all...

    Provided By Norwegian University of Science and Technology

  • White Papers // May 2008

    Dynamic Parameter Tuning for Hardware Prefetching Using Shadow Tagging

    The performance of general purpose microprocessors continues to increase at a rapid pace, but main memory has not been able to keep up. In essence, the processor is able to process several orders of magnitude more data than main memory is able to deliver on time. Numerous techniques have been...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    DYFRAM: Dynamic Fragmentation and Replica Management in Distributed Database Systems

    In distributed database systems, tables are frequently fragmented and replicated over a number of sites in order to reduce network communication costs. How to fragment, when to replicate and how to allocate the fragments to the sites are challenging problems that has previously been solved either by static fragmentation, replication...

    Provided By Norwegian University of Science and Technology

  • White Papers // Apr 2010

    On the Optimal Design of MAC Protocols in Multi-Hop Ad Hoc Networks

    In this paper, the authors present their results on the performance of MAC protocols in multi-hop wireless ad hoc networks in terms of the newly proposed metric "Aggregate multi-hop information efficiency". This metric captures the impact of the traffic conditions, the quality of service requirements for rate and correct packet...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2010

    Evaluating the Information Efficiency of Multi-Hop Networks With Carrier Sensing Capability

    In this contribution, the authors consider the performance of the CSMA MAC protocol in multi-hop ad hoc networks in terms of "Aggregate multi-hop information efficiency". The authors' model consists of a wireless network where transmitter nodes are distributed according to a homogeneous 2-D Poisson point process, and packets are generated...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2009

    Threat Assessment of Wireless Patient Monitoring Systems

    The authors address issues related to threat assessment of mobile patient monitoring systems using a wireless infrastructure including body area biomedical sensor networks. Several user scenarios are presented. Patient sensitive data, mobile and wireless infrastructure, and resource-constraint sensor nodes provide a challenging task of fulfilling some minimum requirements for security,...

    Provided By Norwegian University of Science and Technology

  • White Papers // Dec 2010

    Iterative MMSE Receivers for Multiuser MIMO Cooperative Systems

    In this paper, the authors study a two-user multiple antenna system under quasi-static fading employing a novel scheme that combines cooperation and iterative multiuser detection based on minimum mean square error estimation. They investigate three different receivers: a joint detector for the two users, a separate (per-user) detector, and a...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    Vector Precoding for Gaussian MIMO Broadcast Channels: Impact of Replica Symmetry Breaking

    The so-called "Replica method" of statistical physics is employed for the large system analysis of vector precoding for the Gaussian Multiple-Input Multiple-Output (MIMO) broadcast channel. The transmitter is assumed to comprise a linear front-end combined with nonlinear precoding, that minimizes the front-end imposed transmit energy penalty. Focusing on discrete complex...

    Provided By Norwegian University of Science and Technology

  • White Papers // Aug 2009

    On the Delay-Energy Tradeoff in Multiuser Fading Channels

    The authors consider the delay-energy tradeoff on a fading channel with multiuser diversity. For fixed arbitrary rates of the users, the total transmitted energy is minimized subject to a delay constraint. To achieve this goal they propose a scheme which schedules a subset of all users simultaneously. The scheduled users...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    A Measurement Allocation Scheme for Reliable Data Gathering in Spatially Correlated Sensor Networks

    In this paper, the authors consider the measurement allocation problem in a spatially correlated sensor field. Their goal is to determine the probability of each sensor's being measured based on its contribution to the estimation reliability; it is desirable that a sensor improving the estimation reliability is measured more frequently....

    Provided By Norwegian University of Science and Technology

  • White Papers // Jan 2011

    Efficient Distributed Top-k Query Processing With Caching

    Recently, there has been an increased interest in incorporating in database management systems rank-aware query operators, such as top-k queries, that allow users to retrieve only the most interesting data objects. In this paper, the authors propose a cache-based approach for efficiently supporting top-k queries in distributed database management systems....

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2011

    Cache-Aware Matrix Multiplication on Multicore Systems for IPM-Based LP Solvers

    The authors profile GLPK, an open source linear programming solver, and show empirically that the form of matrix multiplication used in interior point methods takes a significant portion of the total execution time when solving some of the Netlib and other LP data sets. Then, they discuss the drawbacks of...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2011

    Multi-Service Load Balancing in a Heterogeneous Network With Vertical Handover

    In this paper, the authors investigate multi-service load balancing mechanisms in an overlay heterogeneous WiMAX/WLAN network through vertical handover. Considering the service characteristics of the overlay heterogeneous network together with the service requirements of different applications, all streaming applications are served in WiMAX while elastic applications are distributed to WiMAX...

    Provided By Norwegian University of Science and Technology

  • White Papers // Mar 2010

    Performance of Acyclic Stochastic Networks With Network Coding

    Network coding allows a network node to code the information flows before forwarding them. While it has been theoretically proved that network coding can achieve maximum network throughput, the theoretical results usually do not consider the burstiness of data traffic, delays, and the stochastic nature in information processing and transmission....

    Provided By Norwegian University of Science and Technology

  • White Papers // Apr 2010

    On the Validity of the Fixed Point Equation and Decoupling Assumption for Analyzing the 802.11 MAC Protocol

    Performance evaluation of the 802.11 MAC protocol is classically based on the decoupling assumption, which hypothesizes that the backoff processes at different nodes are independent. A necessary condition for the validity of this approach is the existence and uniqueness of a solution to a fixed point equation. However, it was...

    Provided By Norwegian University of Science and Technology

  • White Papers // May 2009

    Basic Theorems on the Backoff Process in 802.11

    Since its introduction, the performance of IEEE 802.11 has attracted a lot of research attention and the center of the attention has been the throughput. For throughput analysis, in the seminal paper by Kumar et al., they axiomized several remarkable observations based on a Fixed Point Equation (FPE). Above all,...

    Provided By Norwegian University of Science and Technology

  • White Papers // Aug 2009

    Energy-Aware Path Selection in Mobile Wireless Sensor Networks: A Dynamic Bayesian Game Approach

    Sensors are energy constrained, which leads to possible selfishness as the sensor may decline to forward packets for other nodes. Sensors also face the problem of unfair depletion of their energy if communication protocols were energy-unaware. To address the above concern, the authors propose the dynamic Bayesian game approach: their...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2011

    Stochastic Network Calculus for Performance Analysis of Internet Networks - An Overview and Outlook

    Stochastic network calculus is a theory for performance guarantee analysis of Internet networks. Originated in early 1990s, stochastic network calculus has its foundation on the min-plus convolution and max-plus convolution queueing principles. Although challenging, it has shown tremendous potential in dealing with queueing type problems encountered in Internet networks. By...

    Provided By Norwegian University of Science and Technology

  • White Papers // Oct 2011

    Performance of Multiuser CDMA Receivers With Bursty Traffic and Delay Constraints

    In this paper, the authors analyze the performance of linear multiuser CDMA receivers under bursty traffic and queuing delay constraints. An ON/OFF source is used to model the traffic burstiness and stochastic network calculus incorporates the queuing delay constraints in the analysis. At the physical layer, adaptive modulation and coding...

    Provided By Norwegian University of Science and Technology

  • White Papers // Jun 2011

    Approximate Fairness Through Limited Flow List

    Most of router mechanisms proposed for fair bandwidth sharing lack either simplicity due to complexity of intricate per flow management of all connections (e.g., WFQ, SFQ), heterogeneity due to a design targeting a specific traffic type, e.g., RED-PD and Fair RED (FRED) or robustness due to requirement for proper router...

    Provided By Norwegian University of Science and Technology

  • White Papers // Feb 2011

    Maximizing Network Revenue Through Resource Management in Heterogeneous Wireless Networks

    Several radio access technologies are now likely to coexist in the same area, and form the so-called heterogeneous wireless networks. In this paper, the authors study the coordination between WiMAX and WiFi through Radio Resource Management (RRM) in order to maximize the network operator's revenue. Two solutions for the optimization...

    Provided By Norwegian University of Science and Technology

  • White Papers // Sep 2010

    On the Flow-Level Delay of a Spatial Multiplexing MIMO Wireless Channel

    The MIMO wireless channel offers a rich ground for quality of service analysis. In this paper, the authors present a stochastic network calculus analysis of a MIMO system, operating in spatial multiplexing mode, using Moment Generating Functions (MGF). They quantify the spatial multiplexing gain, achieved through multiple antennas, for flow...

    Provided By Norwegian University of Science and Technology