Tsinghua University

Displaying 1-40 of 108 results

  • White Papers // Aug 2012

    Distributed Scheduling for Real-Time Convergecast in Wireless Sensor Networks

    Wireless Sensor Networks (WSNs) need to support real time periodic or sporadic queries of physical environments. In this paper, the authors focus on the periodic queries. For each periodic query issued by control applications in a WSN, the data from the source sensors should be collected and/or aggregated to the...

    Provided By Tsinghua University

  • White Papers // Aug 2012

    Triggercast: Enabling Wireless Collisions Constructive

    It is generally considered that concurrent transmissions should be avoided in order to reduce collisions in wireless sensor networks. Constructive Interference (CI) envisions concurrent transmissions to positively interfere at the receiver. CI potentially allows orders of magnitude reductions in energy consumptions and improvements on link quality. In this paper, the...

    Provided By Tsinghua University

  • White Papers // Aug 2012

    Opportunistic Forwarding With Partial Centrality

    In opportunistic networks, the use of social metrics (e.g., degree, closeness and betweenness centrality) of human mobility network, has recently been shown to be an effective solution to improve the performance of opportunistic forwarding algorithms. Most of the current social-based forwarding schemes exploit some globally defined node centrality, resulting in...

    Provided By Tsinghua University

  • White Papers // May 2012

    Lightpath Rerouting in Wavelength-Routed WDM Networks

    Rerouting is a viable and cost-effective approach to decrease the blocking probability in legacy circuit-switched networks. The authors study lightpath rerouting in optical WDM networks in this paper. First, they investigate two different lightpath rerouting strategies, namely, passive rerouting and intentional rerouting. Passive rerouting means the rerouting of existing lightpaths...

    Provided By Tsinghua University

  • White Papers // Apr 2012

    Internet Resource Pricing Models, Mechanisms, and Methods

    With the fast development of video and voice network applications, CDN (Content Distribution Networks) and P2P (Peer-To-Peer) content distribution technologies have gradually matured. How to effectively use Internet resources thus has attracted more and more attentions. For the study of resource pricing, a whole pricing strategy containing pricing models, mechanisms...

    Provided By Tsinghua University

  • White Papers // Mar 2012

    Secure and Scalable Fault Localization Under Dynamic Traffic Patterns

    Compromised and mis-configured routers are a well-known problem in ISP and enterprise networks. Dataplane Fault Localization (FL) aims to identify faulty links of compromised and mis-configured routers during packet forwarding, and is recognized as an effective means of achieving high network availability. Existing secure FL protocols are path-based, which assume...

    Provided By Tsinghua University

  • White Papers // Feb 2012

    Maximum Multiflow in Wireless Network Coding

    In a multi-hop wireless network, wireless interference is crucial to the Maximum Multi-Flow (MMF) problem, which studies the maximum throughput between multiple pairs of sources and sinks. In this paper, the authors observe that network coding could help to decrease the impacts of wireless interference, and propose a framework to...

    Provided By Tsinghua University

  • White Papers // Dec 2011

    An Improved Certificateless Authenticated Key Agreement Protocol

    In this paper, the authors show that their protocol is insecure against a man-in-the-middle attack which is a severe disaster for a key agreement protocol. In addition, the authors claimed that their scheme provides a binding a long-term public key with a corresponding partial private key. In fact, their protocol...

    Provided By Tsinghua University

  • White Papers // Nov 2011

    Flexible Integration of Tunneling and Translation for IPv6 Transition

    The IPv6 transition problem has become the most urgent and practical obstacle holding back the development of the next generation Internet. Various translation and tunneling techniques have been proposed to solve the transition problem. Tunneling satisfies the demand of IPv4-IPv6 traversing while translation achieves IPv4-IPv6 interconnection. However, translation faces several...

    Provided By Tsinghua University

  • White Papers // Nov 2011

    Dynamic Bayesian Spectrum Bargaining With Non-Myopic Users

    In this paper, the authors investigate a cooperative spectrum sharing mechanism realized by a dynamic Bayesian spectrum bargaining between a pair of non-myopic primary user and secondary user. The primary user has only incomplete information of the secondary user's energy cost. They model such a bargaining process as a dynamic...

    Provided By Tsinghua University

  • White Papers // Nov 2011

    A Novel Neighbor Discovery Protocol for Ultraviolet Wireless Networks

    UltraViolet (UV) communication is an attractive option for tactical networks or environmental monitoring. The underlying UV PHY layer has unique characteristics that render previously proposed higher layer protocols for RF communications inappropriate or inefficient. Neighbor discovery is an important functional component of a UV ad hoc wireless network. While there...

    Provided By Tsinghua University

  • White Papers // Oct 2011

    A VLSI Architecture for the Node of Wireless Image Sensor Network

    This paper proposes a novel design of VLSI architecture for the node of wireless image sensor network. This architecture aims at the SoC (System on a Chip) implementation and is composed of a general purpose embedded processor and several dedicated hardware accelerators for image processing and wireless communication. The hardware...

    Provided By Tsinghua University

  • White Papers // Sep 2011

    Provisioning Virtual Resources Adaptively in Elastic Compute Cloud Platforms

    Provisioning Virtual machines on demand is significant in elastic compute cloud for reliable service delivery. The importance and major difficulty lies in satisfying the conflicting objectives of satisfying contracted service level agreement while lowering used resource costs. In this paper, the authors propose a mathematical multi-tier framework for adaptive virtual...

    Provided By Tsinghua University

  • White Papers // Sep 2011

    Win-Coupon: An Incentive Framework for 3G Traffic Offloading

    3G networks are currently facing severe traffic overload problems caused by excessive demands of mobile users. Offloading part of the 3G traffic through other forms of networks, such as Delay Tolerant Networks (DTNs), Wi-Fi hotspots, and Femtocells, is a promising solution. However, since these networks can only provide intermittent and...

    Provided By Tsinghua University

  • White Papers // Sep 2011

    On the Linear Precoder Design for MIMO Channels With Finite-Alphabet Inputs and Statistical CSI

    The theoretic limit on the information rate that a communication channel can support with arbitrary low probability of error is referred to as channel capacity. This capacity is achievable with independent Gaussian distributed inputs for parallel Additive White Gaussian Noise (AWGN) channels and with correlated Gaussian inputs for Multiple-Input Multiple-Output...

    Provided By Tsinghua University

  • White Papers // Sep 2011

    Cloud Testing-Issues, Challenges, Needs and Practice

    Cloud computing not only changes the way of obtaining computing resources (such as computers, infrastructures, data storage, and application services), but also changes the way of managing and delivering computing services, technologies, and solutions. Cloud computing leads an opportunity in offering Testing as a Service (TaaS) for SaaS and clouds....

    Provided By Tsinghua University

  • White Papers // Aug 2011

    Practical Software Model Checking Via Dynamic Interface Reduction

    Implementation-level software model checking explores the state space of a system implementation directly to find potential software defects without requiring any specification or modeling. Despite early successes, the effectiveness of this approach remains severely constrained due to poor scalability caused by state-space explosion. DEMETER makes software model checking more practical...

    Provided By Tsinghua University

  • White Papers // Aug 2011

    Contact Duration Aware Data Replication in Delay Tolerant Networks

    The recent popularization of hand-held mobile devices, such as smartphones, enables the inter-connectivity among mobile users without the support of Internet infrastructure. When mobile users move and contact each other opportunistically, they form a Delay Tolerant Network (DTN), which can be exploited to share data among them. Data replication is...

    Provided By Tsinghua University

  • White Papers // Jul 2011

    Subspace Tracking Based Channel Estimation With Rank Adaptation for OFDM Systems in Sparse Fading Channels

    This paper presents a subspace tracking based channel estimation utilizing Bi-iterative Least-Square (Bi-LS) rank adaptation method in sparse channel for OFDM systems. After modeling parameterized fading channel with sparse multipath, a general description of parametric channel estimation process based on subspace tracking is given. Then a simple Bi-iterative Least-Square (Bi-LS)...

    Provided By Tsinghua University

  • White Papers // Jul 2011

    DHOSPF: Adaptive Parallel Routing Table Computation for Next Generation Routers

    Fast convergence in Interior Gateway Protocol (IGP) is certainly critical to the widespread deployment of real time applications (such as, VOIP, IPTV, etc.). Many improvements for OSPF (Open Shortest Path First) protocol, such as fast hello and fast flooding, have been proposed to reduce the convergence time of IGP. However,...

    Provided By Tsinghua University

  • White Papers // Jun 2011

    StriD2FA: Scalable Regular Expression Matching for Deep Packet Inspection

    Deep Packet Inspection (DPI) has become one of the key components of a Network Intrusion Detection System (NIDS) and it compares packet content against a set of rules written in regular expression. The need to keep up with ever-increasing line speed has forced NIDS designers to move to hardware-based implementation...

    Provided By Tsinghua University

  • White Papers // Jun 2011

    Toward Dynamic Energy-Efficient Operation of Cellular Network Infrastructure

    The operation of cellular network infrastructure incurs significant electrical energy consumption. From the perspective of cellular network operators, reducing this consumption is not only a matter of showing environmental responsibility, but also of substantially reducing their operational expenditure. The authors discuss how dynamic operation of cellular base stations, in which...

    Provided By Tsinghua University

  • White Papers // Jun 2011

    Mitigating Control Channel Saturation in the Dynamic Channel Assignment Protocol

    Multi-channel MAC protocols that rely on a dedicated Control Channel (CC) for data channel reservation face the problem of control channel saturation. When the control channel becomes the bottleneck, data channels are not fully utilized and the spectrum allocated for the network is not used efficiently. For a popular dedicated...

    Provided By Tsinghua University

  • White Papers // May 2011

    An Intelligent Capacity Planning Model for Cloud Market

    Cloud computing is a promising way providing users computing resources. These resources are provided by means of standard computing instances. Currently, there are three price schemas including spot, reservation and on-demand in cloud market, but the average difference among these three pricing schema can be as much as 2.7 times...

    Provided By Tsinghua University

  • White Papers // May 2011

    DAC: Generic and Automatic Address Configuration for Data Center Networks

    Data center networks encode locality and topology information into their server and switch addresses for performance and routing purposes. For this reason, the traditional address configuration protocols such as DHCP require huge amount of manual input, leaving them error-prone. In this paper, the authors present DAC, a generic and automatic...

    Provided By Tsinghua University

  • White Papers // May 2011

    A Novel Joint Synchronization Algorithm for OFDM Systems Based on Single Training Symbol

    The Park's method suffers from symbol timing ambiguity and small acquisition range for carrier frequency offset, and cannot estimate sampling frequency offset. To solve these problems, a new training symbol including virtual carriers is designed, and the corresponding joint synchronization algorithm for Orthogonal Frequency Division Multiplexing (OFDM) systems is proposed....

    Provided By Tsinghua University

  • White Papers // Apr 2011

    Resource Provisioning of Web Applications in Heterogeneous Clouds

    Cloud computing platforms provide very little guarantees regarding the performance of seemingly identical virtual machine instances. Such instances have been shown to exhibit significantly different performance from each other. This heterogeneity creates two challenges when hosting multi-tier Web applications in the Cloud. First, different machine instances have different processing capacity...

    Provided By Tsinghua University

  • White Papers // Mar 2011

    ServerSwitch: A Programmable and High Performance Platform for Data Center Networks

    As one of the fundamental infrastructures for cloud computing, Data Center Networks (DCN) have recently been studied extensively. The authors currently use pure software-based systems, FPGA based platforms, e.g., NetFPGA, or OpenFlow switches, to implement and evaluate various DCN designs including topology design, control plane and routing, and congestion control....

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Dynamic Spectrum Negotiation With Asymmetric Information

    Spectrum scarcity is becoming a serious issue due to the rapid development of wireless communication technology. Dynamic spectrum sharing can effectively improve the spectrum usage by allowing Secondary unlicensed Users (SUs) to dynamically and opportunistically share the spectrum with Primary licensed Users (PUs). In this paper, the authors investigate a...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Examining Cloud Computing From the Perspective of Grid and Computer-Supported Cooperative Work

    Cloud computing, which refers to services provisioning and consumption over the Internet, is the latest paradigm promising to deliver computing as a utility. Though it is still in its infancy and facing many challenges, cloud computing has drawn and is drawing more interest from both academia and industry. Taking grid...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Dynamic Controlling of Data Streaming Applications for Cloud Computing

    Performance of data streaming applications is co-determined by both networking and computing resources, which should be allocated in an integrated and cooperative way. Dynamic controlling of resource allocation is required since unilateral redundancy in networking or computing resources may result in underutilization but not necessarily high performance since insufficiency of...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Improving Routing Scalability With Aggressive Route Aggregation

    The size of the Boarder Gateway Protocol (BGP) routing table is continuously increasing, which incurs more memory demands in routers and increasing BGP update messages between peering routers as well. The RIB/FIB does not scale well with the Internet size, which is known as the routing scalability problem of the...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Guardband Analysis for Distributed OFDMA With User Heterogeneity

    This paper presents an in-depth analysis of the interference strength and required guardband width between coexistent users for distributed Orthogonal Frequency Division Multiple Access (OFDMA). In dynamic spectrum access networks, the cross-band interference between spectrally adjacent users is considered harmful with frequency guardbands inserted between spectrum blocks to eliminate the...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    Partially Overlapping Channel Assignment Based on "Node Orthogonality" for 802.11 Wireless Networks

    In this paper, the authors investigate the problem of partially overlapping channel assignment to improve the performance of 802.11 wireless networks. They first derive a novel interference model that takes into account both the adjacent channel separation and the physical distance of the two nodes employing adjacent channels. This model...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    Linear Precoding for Relay Networks With Finite-Alphabet Constraints

    In this paper, the authors investigate the optimal precoding scheme for relay networks with finite-alphabet constraints. They show that the previous work utilizing various design criteria to maximize either the diversity order or the transmission rate with the Gaussian-input assumption may lead to significant loss for a practical system with...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    DBease: Making Databases User friendly and Easily Accessible

    Structured Query Language (SQL) is a classical way to access relational databases. Although SQL is powerful to query relational databases, it is rather hard for inexperienced users to pose SQL queries, as they are required to be familiar with SQL syntax and have a thorough understanding of the underlying schema....

    Provided By Tsinghua University

  • White Papers // Jan 2011

    QoF: Towards Comprehensive Path Quality Measurement in Wireless Sensor Networks

    Due to its large scale and constrained communication radius, a wireless sensor network mostly relies on multi-hop transmissions to deliver a data packet along a sequence of nodes. It is of essential importance to measure the forwarding quality of multi-hop paths and such information shall be utilized in designing efficient...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    Multi-Hop Access Pricing in Public Area WLANs

    Public area WLANs stand for WLANs deployed in public areas such as classroom and office buildings to provide Internet connections. Nevertheless, such a service may not be always available because of limited AP coverage, poor signal strength, or password authentication. Multi-hop access is a feasible approach to facilitate users without...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    Channel Allocation in Wireless Data Center Networks

    Unbalanced traffic demands of different data center applications are an important issue in designing Data Center Networks (DCNs). In this paper, the authors present the exploratory investigation of utilizing wireless transmissions in DCNs. The paper aims to solve the congestion problem caused by a few hot nodes to improve the...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    SelectCast: Scalable Data Aggregation Scheme in Wireless Sensor Networks

    Data aggregation is a key energy consuming functionality in Wireless Sensor Networks (WSNs) for both data gathering applications and event-based applications, since the communication cost is often the higher-order of the computation cost. It has been shown in the literature that the achievable minimum data rate among all sensor nodes...

    Provided By Tsinghua University

  • White Papers // Apr 2008

    User Behavior Oriented Web Spam Detection

    Combating Web spam has become one of the top challenges for Web search engines. State-of-the-art spam detection techniques are usually designed for specific known types of Web spam and are incapable and inefficient for recently-appeared spam. With user behavior analyses into Web access logs, this paper proposes a spam page...

    Provided By Tsinghua University

  • White Papers // Jun 2008

    System Design Considerations of Highly-Integrated UHF RFID Reader Transceiver RF Front-End

    Nowadays the implementation of highly integrated UHF RFID reader transceiver RF front-ends with excellent performance is demanding and is still challenging. This paper presents a number of design considerations from the system point of view, including the choice of receiver/transmitter front-end architecture, isolation between transmitter and receiver, power efficiency of...

    Provided By Tsinghua University

  • White Papers // Apr 2009

    Higher Dimensional Blue-Noise Sampling Schemes for Curvelet-Based Seismic Data Recovery

    In combination with compressive sensing, a successful reconstruction scheme called Curvelet-based Recovery by Sparsity-promoting Inversion (CRSI) has been developed, and has proven to be useful for seismic data processing. One of the most important issues for CRSI is the sampling scheme, which can greatly affect the quality of reconstruction. Unlike...

    Provided By Tsinghua University

  • White Papers // Sep 2009

    Para-Snort: A Multi-Thread Snort on Multi-Core IA Platform

    As security threats and network bandwidth increase in a very fast pace, there is a growing interest in designing high-performance Network Intrusion Detection System (NIDS). This paper presents a parallelization strategy for the popular open-source Snort to build a high performance NIDS on multi-core IA platform. A modular design of...

    Provided By Tsinghua University

  • White Papers // Jun 2008

    The Design of Vibration Data Acquisition and Intelligent Fault Diagnostic System for Wind Turbine

    In this paper, a vibration data acquisition and intelligent fault diagnostic system is introduced. Firstly, the vibration data acquisition subsystem based on LabView is described in detail. It consists of a wind turbine and a rotor test bed. There are twelve vibration sensors on wind turbine including axial and radial...

    Provided By Tsinghua University

  • White Papers // Jul 2009

    A Security Model for VoIP Steganography

    In 2005, an extensive taxonomy of threats for VoIP was published by a prominent industry group. Strangely, this taxonomy does not identify stegocommunication as a threat, even though many steganographic channels have been identified in VoIP protocols. To avoid such security gaps in the future, the authors' argue that stegocommunication...

    Provided By Tsinghua University

  • White Papers // Oct 2009

    Mirror World Navigation for Mobile Users Based on Augmented Reality

    Finding a destination in unfamiliar environments of complex office building or shopping mall has been always bothering everyone in daily life. Fine-scale directional guidance, a combination of location based service and context aware service, is emerging along with the technology developments of mobile computing, wireless communication, and augmented reality. This...

    Provided By Tsinghua University

  • White Papers // May 2009

    Parallel Evidence Propagation on Multicore Processors

    In this paper designs and implements an efficient technique for parallel evidence propagation on state-of-the-art multicore processor systems. Evidence propagation is a major step in exact inference, a key problem in exploring probabilistic graphical models. This paper proposes a rerooting algorithm to minimize the critical path in evidence propagation. The...

    Provided By Tsinghua University

  • White Papers // Sep 2008

    A Resources Virtualization Approach Supporting Uniform Access to Heterogeneous Grid Resources

    Grid system has various kinds of resources such as computing resources, storage resources, instrument resources, data resources, etc. However, because of the differences of formats, descriptions, structures, and access modes of these resources, grid computing fails to access these resources uniformly and make full use of them. How to organize...

    Provided By Tsinghua University

  • White Papers // Jun 2011

    StriD2FA: Scalable Regular Expression Matching for Deep Packet Inspection

    Deep Packet Inspection (DPI) has become one of the key components of a Network Intrusion Detection System (NIDS) and it compares packet content against a set of rules written in regular expression. The need to keep up with ever-increasing line speed has forced NIDS designers to move to hardware-based implementation...

    Provided By Tsinghua University

  • White Papers // Apr 2010

    Cache-Based Scalable Deep Packet Inspection With Predictive Automaton

    Regular expression (Regex) becomes the standard signature language for security and application detection. Deterministic Finite Automata (DFAs) are widely used to perform multiple regex matching in linear time. However, when implemented by modern memories, the matching speed turns out to be a trade-off with the size of DFA. To improve...

    Provided By Tsinghua University

  • White Papers // Apr 2010

    Independent Parallel Compact Finite Automatons for Accelerating Multi-String Matching

    Multi-string matching is a key technique for implementing network security applications like Network Intrusion Detection Systems (NIDS) and anti-virus scanners. Existing DFA-based research have claimed to achieve high-speed throughput at an expenses of extremely high memory cost, so fail to be used in the embedded systems like high-speed routers where...

    Provided By Tsinghua University

  • White Papers // Feb 2010

    Pattern-Based DFA for Memory-Efficient and Scalable Multiple Regular Expression Matching

    In Network Intrusion Detection System, Deterministic Finite Automaton (DFA) is widely used to compare packet content at a constant speed against a set of patterns specified in regular expressions (regexes). However, combining many regex patterns into a single DFA causes a serious state explosion. Partitioning the pattern set into several...

    Provided By Tsinghua University

  • White Papers // Sep 2010

    Some Foundational Problems in Mobile-Based Services

    The substantial complexity of Mobile-Based Services (MBSes) comes from the need to support flexible policies and provide fault-tolerance while scaling to a large space size, client number and query/update density. Despite impressive progress in characterizing space-temporal indexing of moving objects, many problems remain unsolved, and the behavior of clients is...

    Provided By Tsinghua University

  • White Papers // Jan 2010

    FDI And Spillovers In China: Non-linearity And Absorptive Capacity

    Using a fixed effect variance decomposition model, the authors estimate SUR models to analyze FDI spillovers from contagion and spillovers from competition on local firms in China. While the former type of spillover mainly depends on the degree of foreign presence in the local industry, the latter kind is related...

    Provided By Tsinghua University

  • White Papers // Dec 2008

    The Effects Of The Health Insurance Availability On The Demand-Side: An Impact Evaluation Of China's New Cooperative Medical Scheme

    In 2003, Chinese government launched the pilot program of the New Cooperative Medical Scheme (NCMS), a heavily subsidized voluntary health insurance program for rural residents. It began in 310 rural counties of China's more than 2800 rural counties. By the end of June in 2007, the program had been expanded...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    Does Wireless Sensor Network Scale? a Measurement Study on GreenOrbs

    In spite of the remarkable efforts the community put to build the sensor systems, an essential question still remains unclear at the system level, motivating one to explore the answer from a point of real-world deployment view. Does the wireless sensor network really scale? The authors present findings from a...

    Provided By Tsinghua University

  • White Papers // May 2011

    An Intelligent Capacity Planning Model for Cloud Market

    Cloud computing is a promising way providing users computing resources. These resources are provided by means of standard computing instances. Currently, there are three price schemas including spot, reservation and on-demand in cloud market, but the average difference among these three pricing schema can be as much as 2.7 times...

    Provided By Tsinghua University

  • White Papers // Jan 2011

    Financial Constraints And The Process Of Agglomeration

    One interesting and not well explored topic in finance is the process of "Firm agglomeration". For example, Abercrombie & Fitch and Diebold were both born out of the process of acquisition of independent firms. In the case of Diebold, the acquisition process has focused on firms in different industries (segments),...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Dynamic Controlling of Data Streaming Applications for Cloud Computing

    Performance of data streaming applications is co-determined by both networking and computing resources, which should be allocated in an integrated and cooperative way. Dynamic controlling of resource allocation is required since unilateral redundancy in networking or computing resources may result in underutilization but not necessarily high performance since insufficiency of...

    Provided By Tsinghua University

  • White Papers // Aug 2010

    Traffic-Aware Base Station Sleeping in Dense Cellular Networks

    The energy consumption of Information and Communication Technology (ICT) industry has become a serious problem, which mostly comes from the network infrastructure, rather than the mobile terminals. In this paper, the authors consider densely deployed cellular networks where the coverage of Base Stations (BSs) overlaps and the traffic intensity varies...

    Provided By Tsinghua University

  • White Papers // Aug 2009

    Interference-Aware Relay Selection for Multiple Source-Destination Cooperative Networks

    The authors consider relay selection in a multiple source-destination cooperative network with multiple potential relays. Interference induced by simultaneous transmissions makes relay selection different from interference-free scenarios which has not been well addressed in literature. In this paper, they propose a new relay selection metric in interference-limited networks in order...

    Provided By Tsinghua University

  • White Papers // Dec 2010

    Energy Saving Performance Comparison of Coordinated Multi-Point Transmission and Wireless Relaying

    Currently, two cooperative transmission strategies, Coordinated Multi-Point (CoMP) Transmission and wireless relaying, are expected to be deployed in future cellular systems to improve the performance of cell-edge users. Due to the cooperation diversity, these technologies can potentially lead to more energy saving. Therefore, in this paper, the authors analyze their...

    Provided By Tsinghua University

  • White Papers // Nov 2009

    Lumpy Investment And Corporate Tax Policy

    This paper studies the impact of corporate tax policy on the economy in the presence of both convex and nonconvex capital adjustment costs in a dynamic general equilibrium model. The authors show that corporate tax policy generates both intensive and extensive margin effects via the channel of marginal Q. Its...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Examining Cloud Computing From the Perspective of Grid and Computer-Supported Cooperative Work

    Cloud computing, which refers to services provisioning and consumption over the Internet, is the latest paradigm promising to deliver computing as a utility. Though it is still in its infancy and facing many challenges, cloud computing has drawn and is drawing more interest from both academia and industry. Taking grid...

    Provided By Tsinghua University

  • White Papers // Jun 2011

    Toward Dynamic Energy-Efficient Operation of Cellular Network Infrastructure

    The operation of cellular network infrastructure incurs significant electrical energy consumption. From the perspective of cellular network operators, reducing this consumption is not only a matter of showing environmental responsibility, but also of substantially reducing their operational expenditure. The authors discuss how dynamic operation of cellular base stations, in which...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Improving Routing Scalability With Aggressive Route Aggregation

    The size of the Boarder Gateway Protocol (BGP) routing table is continuously increasing, which incurs more memory demands in routers and increasing BGP update messages between peering routers as well. The RIB/FIB does not scale well with the Internet size, which is known as the routing scalability problem of the...

    Provided By Tsinghua University

  • White Papers // Aug 2009

    Preventing IP Source Address Spoofing: A Two-Level, State Machine-Based Method

    A signature-and-verification-based method, Automatic Peer-to-Peer Anti-spoofing (APPA), is proposed to prevent IP source address spoofing. In this method, signatures are tagged into the packets at the source peer, and verified and removed at the verification peer where packets with incorrect signatures are filtered. A unique state machine, which is used...

    Provided By Tsinghua University

  • White Papers // May 2011

    A Novel Joint Synchronization Algorithm for OFDM Systems Based on Single Training Symbol

    The Park's method suffers from symbol timing ambiguity and small acquisition range for carrier frequency offset, and cannot estimate sampling frequency offset. To solve these problems, a new training symbol including virtual carriers is designed, and the corresponding joint synchronization algorithm for Orthogonal Frequency Division Multiplexing (OFDM) systems is proposed....

    Provided By Tsinghua University

  • White Papers // Jul 2011

    DHOSPF: Adaptive Parallel Routing Table Computation for Next Generation Routers

    Fast convergence in Interior Gateway Protocol (IGP) is certainly critical to the widespread deployment of real time applications (such as, VOIP, IPTV, etc.). Many improvements for OSPF (Open Shortest Path First) protocol, such as fast hello and fast flooding, have been proposed to reduce the convergence time of IGP. However,...

    Provided By Tsinghua University

  • White Papers // Oct 2010

    Aggregate Human Mobility Modeling Using Principal Component Analysis

    Accurate modeling of aggregate human mobility benefits many aspects of cellular mobile networks. Compared with traditional approaches, the cellular networks provide information for aggregate human mobility in urban space with large spatial extent and continuous temporal coverage, due to the high penetration of cell phones. In this paper, a model...

    Provided By Tsinghua University

  • White Papers // Dec 2011

    An Improved Certificateless Authenticated Key Agreement Protocol

    In this paper, the authors show that their protocol is insecure against a man-in-the-middle attack which is a severe disaster for a key agreement protocol. In addition, the authors claimed that their scheme provides a binding a long-term public key with a corresponding partial private key. In fact, their protocol...

    Provided By Tsinghua University

  • White Papers // Feb 2012

    Maximum Multiflow in Wireless Network Coding

    In a multi-hop wireless network, wireless interference is crucial to the Maximum Multi-Flow (MMF) problem, which studies the maximum throughput between multiple pairs of sources and sinks. In this paper, the authors observe that network coding could help to decrease the impacts of wireless interference, and propose a framework to...

    Provided By Tsinghua University

  • White Papers // Apr 2012

    Internet Resource Pricing Models, Mechanisms, and Methods

    With the fast development of video and voice network applications, CDN (Content Distribution Networks) and P2P (Peer-To-Peer) content distribution technologies have gradually matured. How to effectively use Internet resources thus has attracted more and more attentions. For the study of resource pricing, a whole pricing strategy containing pricing models, mechanisms...

    Provided By Tsinghua University

  • White Papers // Nov 2011

    Flexible Integration of Tunneling and Translation for IPv6 Transition

    The IPv6 transition problem has become the most urgent and practical obstacle holding back the development of the next generation Internet. Various translation and tunneling techniques have been proposed to solve the transition problem. Tunneling satisfies the demand of IPv4-IPv6 traversing while translation achieves IPv4-IPv6 interconnection. However, translation faces several...

    Provided By Tsinghua University

  • White Papers // Aug 2011

    Practical Software Model Checking Via Dynamic Interface Reduction

    Implementation-level software model checking explores the state space of a system implementation directly to find potential software defects without requiring any specification or modeling. Despite early successes, the effectiveness of this approach remains severely constrained due to poor scalability caused by state-space explosion. DEMETER makes software model checking more practical...

    Provided By Tsinghua University

  • White Papers // Mar 2012

    Secure and Scalable Fault Localization Under Dynamic Traffic Patterns

    Compromised and mis-configured routers are a well-known problem in ISP and enterprise networks. Dataplane Fault Localization (FL) aims to identify faulty links of compromised and mis-configured routers during packet forwarding, and is recognized as an effective means of achieving high network availability. Existing secure FL protocols are path-based, which assume...

    Provided By Tsinghua University

  • White Papers // Feb 2011

    Guardband Analysis for Distributed OFDMA With User Heterogeneity

    This paper presents an in-depth analysis of the interference strength and required guardband width between coexistent users for distributed Orthogonal Frequency Division Multiple Access (OFDMA). In dynamic spectrum access networks, the cross-band interference between spectrally adjacent users is considered harmful with frequency guardbands inserted between spectrum blocks to eliminate the...

    Provided By Tsinghua University

  • White Papers // Jun 2010

    Measurements, Analysis and Modeling of Private Trackers

    BitTorrent plays a very important role in the current Internet content distribution. The enormous impact of public and private trackers should not be overlooked. Public trackers are suffering from free-riding problem, but private trackers are becoming more and more popular and they run very well in terms of an effective...

    Provided By Tsinghua University

  • White Papers // May 2012

    Lightpath Rerouting in Wavelength-Routed WDM Networks

    Rerouting is a viable and cost-effective approach to decrease the blocking probability in legacy circuit-switched networks. The authors study lightpath rerouting in optical WDM networks in this paper. First, they investigate two different lightpath rerouting strategies, namely, passive rerouting and intentional rerouting. Passive rerouting means the rerouting of existing lightpaths...

    Provided By Tsinghua University