Nanyang Technological University

Displaying 1-40 of 199 results

  • White Papers // Jul 2014

    Modeling and Simulation of Networked Low-Power Embedded Systems: A Taxonomy

    Simulation has been widely adopted for the evaluation of novel protocols or other designs for networked low-power embedded systems, especially for Wireless Sensor Networks (WSNs). A large number of simulation tools have been developed for WSNs in the past few years. However, different tools may emphasize on different features. For...

    Provided By Nanyang Technological University

  • White Papers // Dec 2013

    On the Effectiveness of Polynomial Realization of Reed-Solomon Codes for Storage Systems

    There are different ways to realize Reed Solomon (RS) codes. While in the storage community, using the generator matrices to implement RS codes is more popular, in the coding theory community the generator polynomials are typically used to realize RS codes. Prominent exceptions include HDFS-RAID, which uses generator polynomial based...

    Provided By Nanyang Technological University

  • White Papers // Nov 2013

    Analysis of BLAKE2

    The authors present a thorough security analysis of the hash function family BLAKE2, a recently proposed and already in use tweaked version of the SHA-3 finalist BLAKE. They study how existing attacks on BLAKE apply to BLAKE2 and to what extent the modifications impact the attacks. They design and run...

    Provided By Nanyang Technological University

  • White Papers // Nov 2013

    Revocable IBE Systems with Almost Constant-size Key Update

    It is sometimes necessary to remove keying material from use prior to the end of its normal crypto-period (or key lifetime) for reasons that include key compromise, removal of an entity from an organization, and so on. This process is known as key revocation and is used to explicitly revoke...

    Provided By Nanyang Technological University

  • White Papers // Nov 2013

    Developing a Grey Hat C2 and RAT for APT Security Training and Assessment

    A Remote Access Tool/Trojan (RAT) is a program that allows an external (malicious) operator to invisibly control a host. The operator may examine the system contents, transfer files, and run tools such key- and network sniffers to gain further access. RATs are often inserted on targets by forged e-mails or...

    Provided By Nanyang Technological University

  • White Papers // Nov 2013

    Cryptanalysis of Zorro

    At CHES 2013 was presented a new block cipher called zorro. Although it uses only 4 S-boxes per round, the designers showed the resistance of the cipher against various attacks, and concluded the cipher has a large security margin. In this paper, the authors give a key recovery attack on...

    Provided By Nanyang Technological University

  • White Papers // Oct 2013

    The Resistance of PRESENT-80 Against Related-Key Differential Attacks

    The authors examine the security of the 64-bit lightweight block cipher PRESENT-80 against related-key differential attacks. With a computer search they are able to prove that no related-key differential characteristic exists with probability higher than 2-64 for the full-round PRESENT-80. To overcome the exponential (in the state and key sizes)...

    Provided By Nanyang Technological University

  • White Papers // Oct 2013

    Kernelet: High-Throughput GPU Kernel Executions With Dynamic Slicing and Scheduling

    Graphics processors, or GPUs, have recently been widely used as accelerators in shared environments such as clusters and clouds. In such shared environments, many kernels are submitted to GPUs from different users, and throughput is an important metric for performance and total ownership cost. Despite recently improved runtime support for...

    Provided By Nanyang Technological University

  • White Papers // Oct 2013

    AEGIS: A Fast Authenticated Encryption Algorithm

    In this paper the authors introduce a dedicated authenticated encryption algorithm AEGIS; AEGIS allows for the protection of associated data which makes it very suitable for protecting network packets. AEGIS- 128L uses eight AES round functions to process a 32-byte message block (one step). AEGIS-128 uses five AES round functions...

    Provided By Nanyang Technological University

  • White Papers // Oct 2013

    Write-Only Oblivious RAM Based Privacy-Preserved Access of Outsourced Data

    Oblivious RAM (ORAM) has recently attracted a lot of interest since it can be used to protect the privacy of data user's data access pattern from (honest but curious) outsourced storage. This is achieved by simulating each original data read or write operation with some read and write operations on...

    Provided By Nanyang Technological University

  • White Papers // Sep 2013

    Toward Monetary Cost Effective Content Placement in Cloud Centric Media Network

    In recent years, technical challenges are emerging on how to efficiently distribute the rapid growing User-Generated Contents (UGCs) with long-tailed nature. To address this issue, the authors have previously proposed Cloud Centric Media Network (CCMN) for cost-efficient UGCs delivery. In this paper, they further study the content placement problem in...

    Provided By Nanyang Technological University

  • White Papers // Sep 2013

    The Parallel-Cut Meet-In-The-Middle Attack

    The authors propose a new type of meet-in-the-middle attack that splits the cryptographic primitive in parallel to the execution of the operations. The result of the division is two primitives that have smaller input sizes and thus require lower attack complexities. However, the division is not completely independent and the...

    Provided By Nanyang Technological University

  • White Papers // Sep 2013

    Cryptanalysis of Full RIPEMD-128

    In this paper the authors propose a new cryptanalysis method for double-branch hash functions that they apply on the standard RIPEMD-128, greatly improving over know results. Namely, they were able to build a very good differential path by placing one non-linear differential part in each computation branch of the RIPEMD-128...

    Provided By Nanyang Technological University

  • White Papers // Sep 2013

    Medusa: Simplified Graph Processing on GPUs

    Graphs are common data structures for many applications, and efficient graph processing is a must for application performance. Recently, the Graphics Processing Unit (GPU) has been adopted to accelerate various graph processing algorithms such as BFS and shortest paths. However, it is difficult to write correct and efficient GPU programs...

    Provided By Nanyang Technological University

  • White Papers // Aug 2013

    Revisiting Co-Processing for Hash Joins on the Coupled CPU GPU Architecture

    Query co-processing on Graphics Processor Units (GPUs) has become an effective means to improve the performance of main memory databases. However, the relatively low bandwidth and high latency of the PCI-e bus are usually bottleneck issues for co-processing. Recently, coupled CPU-GPU architectures have received a lot of attention, e.g. AMD...

    Provided By Nanyang Technological University

  • White Papers // Aug 2013

    OmniDB: Towards Portable and Efficient Query Processing on Parallel CPU/GPU Architectures

    Driven by the rapid hardware development of parallel CPU/GPU architectures, the authors have witnessed emerging relational query processing techniques and implementations on those parallel architectures. However, most of those implementations are not portable across different architectures, because they are usually developed from scratch and target at a specific architecture. This...

    Provided By Nanyang Technological University

  • White Papers // Aug 2013

    Parallel Graph Processing on Graphics Processors Made Easy

    In this paper, the authors demonstrate Medusa, a programming frame-work for parallel graph processing on Graphics Processor Units (GPUs). Medusa enables developers to leverage the massive parallelism and other hardware features of GPUs by writing sequential C/C++ code for a small set of APIs. This simplifies the implementation of parallel...

    Provided By Nanyang Technological University

  • White Papers // Aug 2013

    Multiple Limited-Birthday Distinguishers and Applications

    In this paper, the authors propose a new improvement of the rebound techniques, used for crypt-analyzing AES-like permutations during the past years. Their improvement, that allows to reduce the complexity of the attacks, increases the probability of the outbound part by considering a new type of differential paths. Moreover, they...

    Provided By Nanyang Technological University

  • White Papers // Aug 2013

    On Secret Sharing with Nonlinear Product Reconstruction

    Multiplicative linear secret sharing is a fundamental notion in the area of secure Multi-Party Computation (MPC) and, since recently, in the area of two-party cryptography as well. In a nutshell, this notion guarantees that \"The product of two secrets is obtained as a linear function of the vector consisting of...

    Provided By Nanyang Technological University

  • White Papers // Aug 2013

    Towards GPU-Accelerated Large-Scale Graph Processing in the Cloud

    Recently, the authors have witnessed that cloud providers start to offer heterogeneous computing environments. There have been wide interests in both cluster and cloud of adopting Graphics Processors Unit (GPUs) as accelerators for various applications. On the other hand, large-scale processing is important for many data-intensive applications in the cloud....

    Provided By Nanyang Technological University

  • White Papers // Jul 2013

    Matrix Codes and Multitone Frequency Shift Keying for Power Line Communications

    Single-tone Frequency Shift Keying (FSK) modulation with permutation codes has been found to be useful in addressing the problem of narrowband noise disturbance in power line communications. However, this modulation scheme is restrictive since the number of frequencies used must be at least as large as the number of symbols...

    Provided By Nanyang Technological University

  • White Papers // Jul 2013

    Characterizations and Construction Methods for Linear Functional-Repair Storage Codes

    The authors present a precise characterization of linear functional-repair storage codes in terms of admissible states, with each state made up from a collection of vector spaces over some fixed finite field. To illustrate the usefulness of their characterization, they provide several applications. They first describe a simple construction of...

    Provided By Nanyang Technological University

  • White Papers // Jul 2013

    Implementing Lightweight Block Ciphers on x86 Architectures

    Lightweight block ciphers are designed so as to fit into very constrained environments, but usually not really with software performance in mind. For classical lightweight applications where many constrained devices communicate with a server, it is also crucial that the cipher has good software performance on the server side. Recent...

    Provided By Nanyang Technological University

  • White Papers // Jun 2013

    Structural Evaluation of AES and Chosen-Key Distinguisher of 9-round AES-128

    Block ciphers and hash functions are among the most important primitives in cryptography and while their respective goals are different, they are related in many ways. While the symmetric-key cryptography community has now a good experience on how to build a secure and efficient fixed permutation, it remains an open...

    Provided By Nanyang Technological University

  • White Papers // May 2013

    Streamforce: Outsourcing Access Control Enforcement for Stream Data to the Clouds

    As tremendous amount of data being generated everyday from human activity and from devices equipped with sensing capabilities, cloud computing emerges as a scalable and cost-effective platform to store and manage the data. While benefits of cloud computing are numerous, security concerns arising when data and computation are outsourced to...

    Provided By Nanyang Technological University

  • White Papers // May 2013

    Storage Codes: Managing Big Data with Small Overheads

    Erasure coding provides a mechanism to store data redundantly for fault-tolerance in a cost-effective manner. Recently, there has been a renewed interest in designing new erasure coding techniques with different desirable properties, including good repairability and degraded read performance, or efficient redundancy generation processes. Very often, these novel techniques exploit...

    Provided By Nanyang Technological University

  • White Papers // May 2013

    Locally Repairable Codes With Multiple Repair Alternatives

    Distributed storage systems need to store data redundantly in order to provide some fault-tolerance and guarantee system reliability. Different coding techniques have been proposed to provide the required redundancy more efficiently than traditional replication schemes. However, compared to replication, coding techniques are less efficient for repairing lost redundancy, as they...

    Provided By Nanyang Technological University

  • White Papers // Apr 2013

    Network Performance Aware MPI Collective Communication Operations in the Cloud

    In this paper, the authors examine the performance of collective communication operations in Message Passing Interfaces (MPI) in the cloud computing environment. The awareness of network topology has been a key factor in performance optimizations for existing MPI implementations. However, virtualization in the cloud environment not only hides the network...

    Provided By Nanyang Technological University

  • White Papers // Apr 2013

    An Auction Mechanism for Resource Allocation in Mobile Cloud Computing Systems

    A mobile cloud computing system is composed of heterogeneous services and resources to be allocated by the cloud service provider to mobile cloud users. On one hand, some of these resources are substitutable (e.g., users can use storage from different places) that they have similar functions to the users. On...

    Provided By Nanyang Technological University

  • White Papers // Apr 2013

    A Real-Time Group Auction System for Efficient Allocation of Cloud Internet Applications

    Increasing number of the cloud-based Internet applications demands for efficient resource and cost management. This paper proposes a real-time group auction system for the cloud instance market. The system is designed based on a combinatorial double auction, and its applicability and effectiveness are evaluated in terms of resource efficiency and...

    Provided By Nanyang Technological University

  • White Papers // Mar 2013

    Towards Optimal Deployment of Cloud-Assisted Video Distribution Services

    For Internet video services, the high fluctuation of user demands in geographically distributed regions results in low resource utilizations of traditional CDN systems. Due to the capability of rapid and elastic resource provisioning, cloud computing emerges as a new paradigm to reshape the model of video distribution over the Internet,...

    Provided By Nanyang Technological University

  • White Papers // Mar 2013

    Optimizing and Auto-Tuning Iterative Stencil Loops for GPUs with the In-Plane Method

    Stencils represent an important class of computations that are used in many scientific disciplines. Increasingly, many of the stencil computations in scientific applications are being offloaded to GPUs to improve running times. Since a large part of the simulation time is spent inside the stencil kernels, optimizing the kernel is...

    Provided By Nanyang Technological University

  • White Papers // Feb 2013

    The CORE Storage Primitive: Cross-Object Redundancy for Efficient Data Repair & Access in Erasure Coded Storage

    Erasure codes are an integral part of many distributed storage systems aimed at Big Data, since they provide high fault-tolerance for low overheads. However, traditional erasure codes are inefficient on reading stored data in degraded environments (when nodes might be unavailable), and on replenishing lost data (vital for long term...

    Provided By Nanyang Technological University

  • White Papers // Feb 2013

    In-Network Redundancy Generation for Opportunistic Speedup of Data Backup

    Erasure coding is a storage-efficient alternative to replication for achieving reliable data backup in distributed storage systems. During the storage process, traditional erasure codes require a unique source node to create and upload all the redundant data to the different storage nodes. However, such a source node may have limited...

    Provided By Nanyang Technological University

  • White Papers // Jan 2013

    Community Detection in Weighted Networks: Algorithms and Applications

    Community detection is an important issue due to its wide use in designing network protocols such as data forwarding in Delay Tolerant Networks (DTN) and worm containment in Online Social Networks (OSN). However, most of the existing community detection algorithms focus on binary networks. Since most networks are weighted such...

    Provided By Nanyang Technological University

  • White Papers // Jan 2013

    Storage Codes - Coding Rate and Repair Locality

    The repair locality of a distributed storage code is the maximum number of nodes that ever needs to be contacted during the repair of a failed node. Having small repair locality is desirable, since it is proportional to the number of disk accesses during repair. However, recent publications show that...

    Provided By Nanyang Technological University

  • White Papers // Jan 2013

    Green Databases Through Integration of Renewable Energy

    Recently, a lot of energy efficient techniques have been developed to reduce the usage of the carbon intensive energy (brown energy) of databases. There is a new opportunity to reduce the brown energy usage: renewable energy (green energy) has been used to at least partially power computer systems. The key...

    Provided By Nanyang Technological University

  • White Papers // Jan 2013

    An Empirical Investigation of the Impact of Server Virtualization on Energy Efficiency for Green Data Center

    The swift adoption of cloud services is accelerating the deployment of data centers. These data centers are consuming a large amount of energy, which is expected to grow dramatically under the existing technological trends. Therefore, research efforts are in great need to architect green data centers with better energy efficiency....

    Provided By Nanyang Technological University

  • White Papers // Dec 2012

    Robust Performance of Spectrum Sensing in Cognitive Radio Networks

    The successful coexistence of Secondary Users (SUs) and Primary Users (PUs) in cognitive radio networks requires SUs to be spectrum aware and know which spectrum bands are occupied by PUs. Such awareness can be achieved in several ways, one of which is spectrum sensing. While existing spectrum sensing methods usually...

    Provided By Nanyang Technological University

  • White Papers // Dec 2012

    Perceptually Motivated Shape Context Which Uses Shape Interiors

    In this paper, the authors identify some of the limitations of current-day shape matching techniques. They provide examples of how contour-based shape matching techniques cannot provide a good match for certain visually similar shapes. To overcome this limitation, they propose a perceptually motivated variant of the well-known shape context descriptor....

    Provided By Nanyang Technological University

  • White Papers // Sep 2012

    Green-Aware Workload Scheduling in Geographically Distributed Data Centers

    Renewable (or green) energy, such as solar or wind, has at least partially powered data centers to reduce the environmental impact of traditional energy sources (brown energy with high carbon footprint). In this paper, the authors propose a holistic workload scheduling algorithm to minimize the brown energy consumption across multiple...

    Provided By Nanyang Technological University

  • White Papers // Jan 2013

    Community Detection in Weighted Networks: Algorithms and Applications

    Community detection is an important issue due to its wide use in designing network protocols such as data forwarding in Delay Tolerant Networks (DTN) and worm containment in Online Social Networks (OSN). However, most of the existing community detection algorithms focus on binary networks. Since most networks are weighted such...

    Provided By Nanyang Technological University

  • White Papers // Dec 2012

    Robust Performance of Spectrum Sensing in Cognitive Radio Networks

    The successful coexistence of Secondary Users (SUs) and Primary Users (PUs) in cognitive radio networks requires SUs to be spectrum aware and know which spectrum bands are occupied by PUs. Such awareness can be achieved in several ways, one of which is spectrum sensing. While existing spectrum sensing methods usually...

    Provided By Nanyang Technological University

  • White Papers // Apr 2013

    A Real-Time Group Auction System for Efficient Allocation of Cloud Internet Applications

    Increasing number of the cloud-based Internet applications demands for efficient resource and cost management. This paper proposes a real-time group auction system for the cloud instance market. The system is designed based on a combinatorial double auction, and its applicability and effectiveness are evaluated in terms of resource efficiency and...

    Provided By Nanyang Technological University

  • White Papers // Oct 2009

    An Interference Minimization Game Theoretic Subcarrier Allocation Algorithm for OFDMA-Based Distributed Systems

    In this paper, the authors consider a scenario where distributed users in an OFDM-based system share the spectrum for transmission. Each network user (player) comprises a pair of transmit and receive nodes and will be allocated a given number of subcarriers. They propose a utility function that aims at efficiently...

    Provided By Nanyang Technological University

  • White Papers // Oct 2009

    Design of Congestion Control Based on Instantaneous Queue Sizes in the Routers

    Recently, eXplicit Control Protocol (XCP), Rate Control Protocol (RCP), and Adaptive Proportional-Integral Rate Control Protocol (API-RCP) have been proposed for congestion control, with the main objective of achieving fair and maximum bandwidth utilization. However, studies reveal that both RCP and XCP may suffer continuous oscillations due to misestimating the bottleneck...

    Provided By Nanyang Technological University

  • White Papers // Feb 2012

    Improved Linear Precoding Over Block Diagonalization in Multi-Cell Cooperative Networks

    In downlink multiuser Multiple-Input Multiple-Output (MIMO) systems, Block Diagonalization (BD) is a practical linear pre-coding scheme which achieves the same Degrees of Freedom (DoF) as the optimal linear/nonlinear pre-coding schemes. However, its sum-rate performance is rather poor in the practical SNR regime due to the transmit power boost problem. In...

    Provided By Nanyang Technological University

  • White Papers // Dec 2011

    A CMOS Frequency Divider for 2.4/5GHz WLAN Applications With a Simplified Structure

    In this paper, a dual-band integer-N frequency divider is proposed for 2.4/5.2 GHz multi-standard wireless local area networks. It consists of a multi-modulus imbalance phase switching prescaler and two all-stage programmable counters. It is able to provide dual-band operation with high resolution while maintaining a low power consumption. This frequency...

    Provided By Nanyang Technological University

  • White Papers // Oct 2009

    Design of Low Hardware Complexity Filter Banks for Communications Systems Employing Folding Number System

    In this paper, a new architecture to compute 1-D Discrete Wavelet Transform (DWT) based on Folding Number System (FNS) is introduced. Numbers for FNS are extracted directly from analog input without any forward converter like in the Residue Number System (RNS) based DWT. The large Dynamic Range makes the FNS...

    Provided By Nanyang Technological University

  • White Papers // Apr 2013

    An Auction Mechanism for Resource Allocation in Mobile Cloud Computing Systems

    A mobile cloud computing system is composed of heterogeneous services and resources to be allocated by the cloud service provider to mobile cloud users. On one hand, some of these resources are substitutable (e.g., users can use storage from different places) that they have similar functions to the users. On...

    Provided By Nanyang Technological University

  • White Papers // Mar 2013

    Towards Optimal Deployment of Cloud-Assisted Video Distribution Services

    For Internet video services, the high fluctuation of user demands in geographically distributed regions results in low resource utilizations of traditional CDN systems. Due to the capability of rapid and elastic resource provisioning, cloud computing emerges as a new paradigm to reshape the model of video distribution over the Internet,...

    Provided By Nanyang Technological University

  • White Papers // Aug 2012

    On P2P Mechanisms for VM Image Distribution in Cloud Data Centers: Modeling, Analysis and Improvement

    To provide elastic cloud services with QoS guarantee, it is essential for cloud data centers to provision virtual machines rapidly according to user requests. Due to bandwidth bottleneck of centralized model, P2P model is recently adopted in data centers to relieve server workload by enabling sharing among VM instances. In...

    Provided By Nanyang Technological University

  • White Papers // May 2013

    Streamforce: Outsourcing Access Control Enforcement for Stream Data to the Clouds

    As tremendous amount of data being generated everyday from human activity and from devices equipped with sensing capabilities, cloud computing emerges as a scalable and cost-effective platform to store and manage the data. While benefits of cloud computing are numerous, security concerns arising when data and computation are outsourced to...

    Provided By Nanyang Technological University

  • White Papers // Apr 2013

    Network Performance Aware MPI Collective Communication Operations in the Cloud

    In this paper, the authors examine the performance of collective communication operations in Message Passing Interfaces (MPI) in the cloud computing environment. The awareness of network topology has been a key factor in performance optimizations for existing MPI implementations. However, virtualization in the cloud environment not only hides the network...

    Provided By Nanyang Technological University

  • White Papers // Oct 2012

    Decentralized Erasure Coding for Efficient Data Archival in Distributed Storage Systems

    Distributed storage systems usually achieve fault tolerance by replicating data across different nodes. However, redundancy schemes based on erasure codes can provide a storage-efficient alternative to replication. This is particularly suited for data archival since archived data is rarely accessed. Typically, the migration to erasure-encoded storage does not leverage on...

    Provided By Nanyang Technological University

  • White Papers // May 2013

    Locally Repairable Codes With Multiple Repair Alternatives

    Distributed storage systems need to store data redundantly in order to provide some fault-tolerance and guarantee system reliability. Different coding techniques have been proposed to provide the required redundancy more efficiently than traditional replication schemes. However, compared to replication, coding techniques are less efficient for repairing lost redundancy, as they...

    Provided By Nanyang Technological University

  • White Papers // Feb 2013

    The CORE Storage Primitive: Cross-Object Redundancy for Efficient Data Repair & Access in Erasure Coded Storage

    Erasure codes are an integral part of many distributed storage systems aimed at Big Data, since they provide high fault-tolerance for low overheads. However, traditional erasure codes are inefficient on reading stored data in degraded environments (when nodes might be unavailable), and on replenishing lost data (vital for long term...

    Provided By Nanyang Technological University

  • White Papers // Feb 2013

    In-Network Redundancy Generation for Opportunistic Speedup of Data Backup

    Erasure coding is a storage-efficient alternative to replication for achieving reliable data backup in distributed storage systems. During the storage process, traditional erasure codes require a unique source node to create and upload all the redundant data to the different storage nodes. However, such a source node may have limited...

    Provided By Nanyang Technological University

  • White Papers // Aug 2012

    RapidRAID: Pipelined Erasure Codes for Fast Data Archival in Distributed Storage Systems

    To achieve reliability in distributed storage systems, data has usually been replicated across different nodes. However the increasing volume of data to be stored has motivated the introduction of erasure codes, a storage efficient alternative to replication, particularly suited for archival in data centers, where old datasets (rarely accessed) can...

    Provided By Nanyang Technological University

  • White Papers // Nov 2012

    Data Insertion & Archiving in Erasure-Coding Based Large-Scale Storage Systems

    Given the vast volume of data that needs to be stored reliably, many data-centers and large-scale file systems have started using erasure codes to achieve reliable storage while keeping the storage overhead low. This has invigorated the research on erasure codes tailor made to achieve different desirable storage system properties...

    Provided By Nanyang Technological University

  • White Papers // Jul 2012

    Energy Optimizations for Data Center Network: Formulation and Its Solution

    Data center consumes increasing amount of power nowadays, together with expanding number of data centers and upgrading data center scale, its power consumption becomes a knotty issue. While main efforts of this research focus on server and storage power reduction, network devices as part of the key components of data...

    Provided By Nanyang Technological University

  • White Papers // Aug 2012

    Content Routing and Lookup Schemes Using Global Bloom Filter for Content-Delivery-as-a-Service

    Leveraging cloud computing technology, the authors have proposed Content-Delivery-as-a-Service (CoDaaS) to distribute User Generated Content (UGC) in an efficient and economical fashion. However, due to the exponential increases of Internet traffic, traditional hashing-based content routing and lookup scheme suffers from high delay. This paper introduces a global Compressed Counting Bloom...

    Provided By Nanyang Technological University

  • White Papers // Jul 2012

    Optimizing Content Retrieval Delay for LT-Based Distributed Cloud Storage Systems

    Among different setups of cloud storage systems, fountain-codes based distributed cloud storage system provides reliable online storage solution through placing coded content fragments into multiple storage nodes. Luby Transform (LT) code is one of the popular fountain codes for storage systems due to its efficient recovery. However, to ensure high...

    Provided By Nanyang Technological University

  • White Papers // Aug 2012

    Socially-Responsible Load Scheduling Algorithms for Sustainable Data Centers Over Smart Grid

    Power consumption of data centers accounts for a significant portion of operational cost for service providers. However, it is not sufficient to minimize electricity cost only. Instead, service providers should also consider the sustainability of data centers. In this paper, the authors investigate the problem of socially-responsible load scheduling for...

    Provided By Nanyang Technological University

  • White Papers // Jul 2012

    QoE-Driven Cache Management for HTTP Adaptive Bit Rate (ABR) Streaming Over Wireless Networks

    In this paper, the authors investigate the problem of how to cache a set of media files with optimal streaming rates, under HTTP adaptive bit rate streaming over wireless networks. The design objective is to achieve the optimal expected QoE under a limited storage budget, which is measured by the...

    Provided By Nanyang Technological University

  • White Papers // May 2012

    Efficient Spatial Keyword Search in Trajectory Databases

    An increasing amount of trajectory data is being annotated with text descriptions to better capture the semantics associated with locations. The fusion of spatial locations and text descriptions in trajectories engenders a new type of top-k queries that take into account both aspects. Each trajectory in consideration consists of a...

    Provided By Nanyang Technological University

  • White Papers // May 2012

    Cloud and the City: Facilitating Flexible Access Control over Data Streams

    The proliferation of sensing devices create plethora of data-streams, which in turn can be harnessed to carry out sophisticated analytics to support various real-time applications and services as well as long-term planning, e.g., in the context of intelligent cities or smart homes to name a few prominent ones. A mature...

    Provided By Nanyang Technological University

  • White Papers // Jul 2012

    A GPS Pseudorange Based Cooperative Vehicular Distance Measurement Technique

    Accurate vehicular localization is important for various Cooperative Vehicle Safety (CVS) applications such as collision avoidance, turning assistant, etc. In this paper, the authors propose a cooperative vehicular distance measurement technique based on the sharing of GPS pseudorange measurements and a weighted least squares method. The classic double difference pseudorange...

    Provided By Nanyang Technological University

  • White Papers // Dec 2012

    Cluster-Based Transform Domain Communication Systems for High Spectrum Efficiency

    This paper presents a cluster-based Transform Domain Communication System (TDCS) to improve spectrum efficiency. Unlike the utilities of clusters in Orthogonal Frequency Division Multiplex (OFDM) systems, the cluster-based TDCS framework divides entire unoccupied spectrum bins into L clusters, where each one represents a data steam independently, to achieve L times...

    Provided By Nanyang Technological University

  • White Papers // Dec 2012

    Perceptually Motivated Shape Context Which Uses Shape Interiors

    In this paper, the authors identify some of the limitations of current-day shape matching techniques. They provide examples of how contour-based shape matching techniques cannot provide a good match for certain visually similar shapes. To overcome this limitation, they propose a perceptually motivated variant of the well-known shape context descriptor....

    Provided By Nanyang Technological University

  • White Papers // May 2011

    On Secure Index Coding with Side Information

    The problem of Index Coding with Side Information (ICSI) was introduced by Birk and Kol. It considers a communications scenario with one server and many clients. Each client misses a certain part of the data, due to intermittent reception, limited storage capacity or any other reasons. Security aspects of the...

    Provided By Nanyang Technological University

  • White Papers // Jan 2013

    Green Databases Through Integration of Renewable Energy

    Recently, a lot of energy efficient techniques have been developed to reduce the usage of the carbon intensive energy (brown energy) of databases. There is a new opportunity to reduce the brown energy usage: renewable energy (green energy) has been used to at least partially power computer systems. The key...

    Provided By Nanyang Technological University

  • White Papers // May 2011

    Guest Editorial: Special Issue on Cloud Computing

    Cloud computing has been gaining more acceptance thanks to the benefits it offers to customers including increased scalability, higher reliability, cost reduction, and higher accessibility. For example, customers such as small sized companies are able to offload the important tasks of data storage and computation because of these services offered...

    Provided By Nanyang Technological University

  • White Papers // Dec 2008

    Spectrally Efficient Sensing Protocol for Cognitive Relay Systems

    The authors propose sensing protocols for a cognitive dual-hop relay system where transmission from Source (S) to Destination (D) is accomplished over two phases with the assistance of a Relay (R). A naive sensing protocol is to perform sensing at S and R before the respective transmission phase. This leads...

    Provided By Nanyang Technological University

  • White Papers // Feb 2009

    High Rate Open-Loop MIMO Multi-User Downlink Transmission Scheme Based on BP-QO-STBC

    In this paper, the authors first propose a new class of full rate full diversity Quasi-Orthogonal Space Time Block Code (QO-STBC), namely QO-STBC with Blind Precoding (BP-QO-STBC). Based on this code, a novel open-loop MIMO multi-user downlink transmission scheme is derived. The proposed scheme is extendable by simple iterative construction...

    Provided By Nanyang Technological University

  • White Papers // Feb 2009

    Analytical Performance of OFDM Systems Impaired by a Nonlinear HPA With Memory

    The performance of modern communication transmitters utilizing multi-carrier modulation techniques is highly sensitive to nonlinear distortions arising mainly from the High Power Amplifier (HPA). In addition, the wideband characteristics of multi-carrier signals results in frequency dependent distortions, typically known as memory effects. This paper aims to analytically evaluate the impact...

    Provided By Nanyang Technological University

  • White Papers // Jun 2011

    On Throughput and Delay Scaling With Cooperative Spectrum Sharing

    In this paper, the authors propose a cooperative spectrum sharing protocol between two overlapping static ad hoc wireless networks where the primary and secondary networks consist of n and m randomly distributed nodes respectively. The secondary network achieves spectrum access along with the primary network by allowing its nodes to...

    Provided By Nanyang Technological University

  • White Papers // Oct 2010

    Preliminary Measurement Results for Cognitive Spectrum Sharing Based on Cooperative Relaying

    In this paper, the authors have designed and developed a test-bed for proof-of-concept demonstration and performance assessment of a cognitive spectrum sharing protocol based on cooperative relaying. The Packet Error Rate (PER) for both primary and secondary systems are measured to quantify their respective performance. Spectrum access probability for the...

    Provided By Nanyang Technological University

  • White Papers // May 2009

    Joint Network and Channel Coding for Wireless Networks

    In this paper, a Joint Network and Channel Coding (JNCC) strategy with retransmissions is proposed for two canonical network elements, Broadcast Channel with receiver side Information (BC-SI) and orthogonal Multiple Access Channel with Correlated Sources (MAC-CS). By extending the derived results for BC-SI and orthogonal MAC-CS to a multi-hop wireless...

    Provided By Nanyang Technological University

  • White Papers // Oct 2010

    Interference-Free Overlay Cognitive Radio Network Based on Cooperative Space Time Coding

    In this paper, the authors propose a two-phase overlay spectrum sharing protocol based on cooperative Decode-and-Forward relaying which allows the secondary system to gain spectrum access along with the primary system. In the proposed scheme, the secondary system operates simultaneously in the same frequency band as the primary system, which...

    Provided By Nanyang Technological University