Ohio State University

Displaying 1-40 of 172 results

  • White Papers // Apr 2014

    When Queueing Meets Coding: Optimal-Latency Data Retrieving Scheme in Storage Clouds

    Storage clouds, such as Amazon S3, are being widely used for web services and Internet applications. It has been observed that the delay for retrieving data from and placing data into the clouds is quite random, and exhibits weak correlations between different read/write requests. This inspires the authors to investigate...

    Provided By Ohio State University

  • White Papers // Mar 2014

    A System for Energy-Efficient Data Management

    Energy consumption of computer systems has increased at a steep rate in recent years. Following extensive energy-related research and practice in the hardware and OS communities, much attention has been paid to developing energy-efficient applications. With database systems being a heavy energy consumer in modern data centers, the authors face...

    Provided By Ohio State University

  • White Papers // Feb 2014

    On Big Data Benchmarking

    Big data systems address the challenges of capturing, storing, managing, analyzing, and visualizing big data. Within this context, developing benchmarks to evaluate and compare big data systems has become an active topic for both research and industry communities. To date, most of the state-of-the-art big data benchmarks are designed for...

    Provided By Ohio State University

  • White Papers // Jan 2014

    Efficient, Accurate and Privacy-Preserving Data Mining for Frequent Itemsets in Distributed Databases

    Mining distributed databases is emerging as a fundamental computational problem. A common approach for mining distributed databases is to move all of the data from each database to a central site and a single model is built. This approach is accurate, but too expensive in terms of time required. For...

    Provided By Ohio State University

  • White Papers // Oct 2013

    Systematic Testing for Resource Leaks in Android Applications

    The use of mobile devices and the complexity of their software continue to grow rapidly. This growth presents significant challenges for software correctness and performance. In addition to traditional defects, a key consideration are defects related to the limited resources available on these devices. Resource leaks in an application, due...

    Provided By Ohio State University

  • White Papers // Mar 2013

    Life-Add: Lifetime Adjustable Design for WiFi Networks With Heterogeneous Energy Supplies

    WiFi usage significantly reduces the battery lifetime of handheld devices such as Smartphones and tablets, due to its high energy consumption. In this paper, the authors propose "Life-Add": a Lifetime Adjustable design for WiFi networks, where the devices are powered by battery, electric power, and/or renewable energy. In Life-Add, a...

    Provided By Ohio State University

  • White Papers // Feb 2013

    Retransmission Delays With Bounded Packets: Power Law Body and Exponential Tail

    Retransmissions serve as the basic building block that communication protocols use to achieve reliable data transfer. Until recently, the number of retransmissions were thought to follow a geometric (light-tailed) distribution. However, recent work shows that when the distribution of the packet sizes have infinite support, retransmission-based protocols may result in...

    Provided By Ohio State University

  • White Papers // Jan 2013

    On Sample-Path Optimal Dynamic Scheduling for Sum-Queue Minimization in Forests

    The authors investigate the problem of minimizing the sum of the queue lengths of all the nodes in a wireless network with a forest topology. Each packet is destined to one of the roots (sinks) of the forest. They consider a time-slotted system, and a primary (or one-hop) interference model....

    Provided By Ohio State University

  • White Papers // Jan 2013

    Network Control Without CSI Using Rateless Codes for Downlink Cellular Systems

    Wireless network scheduling and control techniques (e.g., opportunistic scheduling) rely heavily on access to Channel State Information (CSI). However, obtaining this information is costly in terms of bandwidth, time, and power, and could result in large overhead. Therefore, a critical question is how to optimally manage network resources in the...

    Provided By Ohio State University

  • White Papers // Jan 2013

    LDPC-in-SSD: Making Advanced Error Correction Codes Work Effectively in Solid State Drives

    Conventional Error Correction Codes (ECCs), such as the commonly used BCH code, have become increasingly inadequate for Solid State Drives (SSDs) as the capacity of NAND flash memory continues to increase and its reliability continues to degrade. It is highly desirable to deploy a much more powerful ECC, such as...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Understanding the Robustness of SSDs Under Power Fault

    Modern storage technology (SSDs, No-SQL databases, commoditized RAID hardware, etc.) bring new reliability challenges to the already complicated storage stack. Among other things, the behavior of these new components during power faults - which happen relatively frequently in data centers - is an important yet mostly ignored issue in this...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Exploiting Double Opportunities for Deadline Based Content Propagation in Wireless Networks

    In this paper, the authors focus on mobile wireless networks comprising of a powerful communication center and a multitude of mobile users. They investigate the propagation of deadline-based content in the wireless network characterized by heterogeneous (time-varying and user-dependent) wireless channel conditions, heterogeneous user mobility, and where communication could occur...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Online Packet Scheduling With Hard Deadlines in Multihop Communication Networks

    The problem of online job or packet scheduling with hard deadlines has been studied extensively in the single hop setting, whereas it is notoriously difficult in the multihop setting. This difficulty stems from the fact that packet scheduling decisions at each hop influences and is influenced by decisions on other...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Distributed Cross-Layer Optimization in Wireless Networks: A Second-Order Approach

    Due to the rapidly growing scale and heterogeneity of wireless networks, the design of distributed cross-layer optimization algorithms has received significant interest from the networking research community. So far, the standard distributed cross-layer approach in the literature is based on the first-order Lagrangian dual decomposition and the sub-gradient method, which...

    Provided By Ohio State University

  • White Papers // Jan 2013

    An Economic Analysis of Regulating Security Investments in the Internet

    Regulating the ISPs to adopt more security measures has been proposed as an effective method in mitigating the threats of attacks in the Internet. However, economic incentives of the ISPs and the network effects of security measures can lead to an under-investment in their adoption. The authors study the potential...

    Provided By Ohio State University

  • White Papers // Jan 2013

    A New Analytical Technique for Designing Provably Efficient MapReduce Schedulers

    With the rapid increase in size and number of jobs that are being processed in the MapReduce framework, efficiently scheduling jobs under this framework is becoming increasingly important. The authors consider the problem of minimizing the total flow-time of a sequence of jobs in the MapReduce framework, where the jobs...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Exploring the Inefficiency and Instability of Back-Pressure Algorithms

    In this paper, the authors focus on the issue of stability in multi-hop wireless networks under flow-level dynamics, and explore the inefficiency and instability of the celebrated Back-Pressure algorithms. It has been well-known that the Back-Pressure (or MaxWeight) algorithms achieve queue stability and throughput optimality in a wide variety of...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Maximizing Social Welfare in Operator-Based Cognitive Radio Networks Under Spectrum Uncertainty and Sensing Inaccuracy

    In Cognitive Radio Networks (CRNs), Secondary Users (SUs) are allowed to opportunistically access the unused/under-utilized channels of Primary Users (PUs). To utilize spectrum resources efficiently, an auction scheme is often applied where an operator serves as an auctioneer and accepts spectrum requests from SUs. Most existing works on spectrum auctions...

    Provided By Ohio State University

  • White Papers // Jan 2013

    Providing Probabilistic Guarantees on the Time of Information Spread in Opportunistic Networks

    Spreading patterns of pandemics, computer viruses, and information have been widely studied in various research disciplines including epidemics, biology, physics, sociology, and computer networks. In these disciplines, most studies have been devoted to characterizing spread behaviors toward a network of mobile agents including humans, vehicles, and mobile devices over time....

    Provided By Ohio State University

  • White Papers // Dec 2012

    Performance of Low-Complexity Greedy Scheduling Policies in Multi-Channel Wireless Networks: Optimal Throughput and Near-Optimal Delay

    In this paper, the authors focus on the scheduling problem in multi-channel wireless networks, e.g., the downlink of a single cell in Fourth Generation (4G) OFDM-based cellular networks. Their goal is to design efficient scheduling policies that can achieve provably good performance in terms of both throughput and delay, at...

    Provided By Ohio State University

  • White Papers // Nov 2012

    Maximizing Information in Unreliable Sensor Networks Under Deadline and Energy Constraints

    The authors study the problem of maximizing the information in a wireless sensor network with unreliable links. They consider a sensor network with a tree topology, where the root corresponds to the sink, and the rest of the network detects an event and transmits data to the sink. They formulate...

    Provided By Ohio State University

  • White Papers // Oct 2012

    Performance Analysis of Work-Conserving Schedulers for Minimizing Total Flow-Time With Phase Precedence

    The authors consider the problem of minimizing the total flow-time of multiple jobs in a pool of multiple homogeneous machines, where the jobs arrive over time and have to be served with phase precedence. This is a common occurrence in job scheduling for the increasingly popular data center oriented systems,...

    Provided By Ohio State University

  • White Papers // Oct 2012

    An Extended Reduction Based Parallel Programming Paradigm with Low Overhead Fault-Tolerance Support

    It is widely accepted that the existing MPI-based fault-tolerance solutions will not be applicable in the exascale era, as with growing level of concurrency and relatively lower I/O bandwidths, the time required to complete a check-point can exceed the Mean-Time To Failure (MTTF). In this paper, the authors show that...

    Provided By Ohio State University

  • White Papers // Sep 2012

    A High-Fidelity Temperature Distribution Forecasting System for Data Centers

    Data centers have become a critical computing infrastructure in the era of cloud computing. Temperature monitoring and forecasting are essential for preventing over heating induced server shutdowns and improving a data center's energy efficiency. This paper presents a novel cyber-physical approach for temperature forecasting in data centers, which integrates Computational...

    Provided By Ohio State University

  • White Papers // Sep 2012

    Maximizing System Throughput Using Cooperative Sensing in Multi-Channel Cognitive Radio Networks

    In Cognitive Radio Networks (CRNs), unlicensed users are allowed to access the licensed spectrum when it is not currently being used by Primary Users (PUs). To guarantee a high system throughput in CRNs, the channel state of PUs needs to be accurately detected to reduce conflict. To this end, cooperative...

    Provided By Ohio State University

  • White Papers // Aug 2012

    A Fault-Tolerant Environment for Large-Scale Query Processing

    As datasets are increasing in size, the data management and processing needs are being met with added parallelism, i.e., by involving more nodes and/or cores in the system. This, in turn, is increasing the chances of failures during processing. In this paper, the authors present the design and implementation of...

    Provided By Ohio State University

  • White Papers // Jun 2012

    Low-Complexity Optimal Scheduling Over Correlated Fading Channels With ARQ Feedback

    The authors investigate the downlink scheduling problem under Markovian ON/OFF fading channels, where the instantaneous channel state information is not directly accessible, but is revealed via ARQ-type feedback. The scheduler can exploit the temporal correlation/channel memory inherent in the Markovian channels to improve network performance. However, designing low-complexity and throughput-optimal...

    Provided By Ohio State University

  • White Papers // May 2012

    On Wireless Network Infrastructure Optimization for Cyber-Physical Systems in Future Smart Buildings

    Today, most Cyber-Physical Systems (CPS) in smart buildings require a wireless-based network infrastructure for sensing, communication, and actuation. In such CPSs, the energy expenditure and hence battery lifetime of the wireless network infrastructure depend heavily upon the placement of the Base Stations (BS). However, in indoor environments, BS placement is...

    Provided By Ohio State University

  • White Papers // Apr 2012

    Scheduling Heterogeneous Delay Tolerant Tasks in Smart Grid With Renewable Energy

    The smart grid is the new generation of electricity grid that can efficiently facilitate new distributed sources of energy (e.g., harvested renewable energy), and allow for dynamic electricity price. In this paper, the authors investigate the cost minimization problem for an end-user, such as a home, community, or a business,...

    Provided By Ohio State University

  • White Papers // Apr 2012

    Maximizing a Submodular Utility for Deadline Constrained Data Collection in Sensor Networks

    The authors study the utility maximization problem for data collection in sensor networks subject to a deadline constraint, where the data on a selected subset of nodes are collected through a routing tree rooted at a sink subject to the 1-hop interference model. Their problem can be viewed as a...

    Provided By Ohio State University

  • White Papers // Mar 2012

    Design of a Power Efficient Cloud Computing Environment: Heavy Traffic Limits and QoS

    Cloud computing is fast being deployed by the industry as a means to provide efficient computing resources. A significant fraction of the overall cost of cloud computing operation is the amount of power it consumes, which is related to the number of machines in operation. In order to efficiently manage...

    Provided By Ohio State University

  • White Papers // Mar 2012

    Spammer Behavior Analysis and Detection in User Generated Content on Social Networks

    Spam content is surging with an explosive increase of User Generated Content (UGC) on the Internet. Spammers often insert popular keywords or simply copy and paste recent articles from the Web with spam links inserted, attempting to disable content-based detection. In order to effectively detect spam in user generated content,...

    Provided By Ohio State University

  • White Papers // Feb 2012

    Tracking Conflicting Accesses Efficiently for Software Record and Replay

    Record and replay, which records a multithreaded program's execution in one run and reproduces it deterministically in a second run, is useful for program debugging, fault detection and analysis. The key challenge in multithreaded record and replay is ensuring that conflicting, cross-thread accesses to shared variables are properly detected, recorded...

    Provided By Ohio State University

  • White Papers // Jan 2012

    TurfCast: A Service for Controlling Information Dissemination in Wireless Networks

    Recent years have witnessed mass proliferation of mobile devices with rich wireless communication capabilities as well as emerging mobile device based information dissemination applications that leverage these capabilities. This paper proposes TurfCast, a novel information dissemination service that selectively broadcasts information in particular "Turfs," abstract logical spaces in which receivers...

    Provided By Ohio State University

  • White Papers // Jan 2012

    A Distributed Newton's Method for Joint Multi-Hop Routing and Flow Control: Theory and Algorithm

    The fast growing scale and heterogeneity of current communication networks necessitate the design of distributed cross-layer optimization algorithms. So far, the standard approach of distributed cross-layer design is based on dual decomposition and the sub-gradient algorithm, which is a first-order method that has a slow convergence rate. In this paper,...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Maximizing System Throughput by Cooperative Sensing in Cognitive Radio Networks

    Cognitive Radio Networks allow unlicensed users to opportunistically access the licensed spectrum without causing disruptive interference to the Primary Users (PUs). One of the main challenges in CRNs is the ability to detect PU transmissions. Recent works have suggested the use of Secondary User (SU) cooperation over individual sensing to...

    Provided By Ohio State University

  • White Papers // Jan 2012

    A Hierarchy-Based Fault-Local Stabilizing Algorithm for Tracking in Sensor Networks

    In this paper, the authors introduce the concept of hierarchy-based fault-local stabilization and a novel self-healing/fault-containment technique and apply them in Stalk. Stalk is an algorithm for tracking in sensor networks that maintains a data structure on top of an underlying hierarchical partitioning of the network. Starting from an arbitrarily...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Design and Analysis of a Fast Local Clustering Service for Wireless Sensor Networks

    The authors present a fast local clustering service, FLOC, that partitions a multi-hop wireless network into non-overlapping and approximately equal-sized clusters. Each cluster has a cluster-head such that all nodes within unit distance of the cluster-head belong to the cluster but no node beyond distance m from the cluster-head belongs...

    Provided By Ohio State University

  • White Papers // Jan 2012

    On the Secrecy Capacity of Fading Channels

    The authors consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. They eavesdropper can be viewed as the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long coherence intervals. They first...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Loss-Tolerant Real-Time Content Integrity Validation for P2P Video Streaming

    The use of Peer-To-Peer (P2P) mechanisms for content delivery is attractive to content and service providers alike. P2P data transfers offload the demand on servers and reduce the bandwidth requirements, with corresponding benefits of improved scalability and performance. This, however, poses interesting challenges in ensuring content integrity. Peers may be...

    Provided By Ohio State University

  • White Papers // Jan 2012

    A Hierarchy-Based Fault-Local Stabilizing Algorithm for Tracking in Sensor Networks

    In this paper, the authors introduce the concept of hierarchy-based fault-local stabilization and a novel self-healing/fault-containment technique and apply them in Stalk. Stalk is an algorithm for tracking in sensor networks that maintains a data structure on top of an underlying hierarchical partitioning of the network. Starting from an arbitrarily...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Design and Analysis of a Fast Local Clustering Service for Wireless Sensor Networks

    The authors present a fast local clustering service, FLOC, that partitions a multi-hop wireless network into non-overlapping and approximately equal-sized clusters. Each cluster has a cluster-head such that all nodes within unit distance of the cluster-head belong to the cluster but no node beyond distance m from the cluster-head belongs...

    Provided By Ohio State University

  • White Papers // Jan 2012

    On the Secrecy Capacity of Fading Channels

    The authors consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. They eavesdropper can be viewed as the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long coherence intervals. They first...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Loss-Tolerant Real-Time Content Integrity Validation for P2P Video Streaming

    The use of Peer-To-Peer (P2P) mechanisms for content delivery is attractive to content and service providers alike. P2P data transfers offload the demand on servers and reduce the bandwidth requirements, with corresponding benefits of improved scalability and performance. This, however, poses interesting challenges in ensuring content integrity. Peers may be...

    Provided By Ohio State University

  • White Papers // Apr 2012

    Maximizing a Submodular Utility for Deadline Constrained Data Collection in Sensor Networks

    The authors study the utility maximization problem for data collection in sensor networks subject to a deadline constraint, where the data on a selected subset of nodes are collected through a routing tree rooted at a sink subject to the 1-hop interference model. Their problem can be viewed as a...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Maximizing System Throughput by Cooperative Sensing in Cognitive Radio Networks

    Cognitive Radio Networks allow unlicensed users to opportunistically access the licensed spectrum without causing disruptive interference to the Primary Users (PUs). One of the main challenges in CRNs is the ability to detect PU transmissions. Recent works have suggested the use of Secondary User (SU) cooperation over individual sensing to...

    Provided By Ohio State University

  • White Papers // Jan 2012

    TurfCast: A Service for Controlling Information Dissemination in Wireless Networks

    Recent years have witnessed mass proliferation of mobile devices with rich wireless communication capabilities as well as emerging mobile device based information dissemination applications that leverage these capabilities. This paper proposes TurfCast, a novel information dissemination service that selectively broadcasts information in particular "Turfs," abstract logical spaces in which receivers...

    Provided By Ohio State University

  • White Papers // Sep 2010

    DiffUser: Differentiated User Access Control on Smartphones

    Smartphones have been widely used in recent years due to their capabilities of supporting many applications from simple Short Message Service messages to complicated Location-based services. It is challenging for Smartphones to enable their end users to manage all applications in all possible use cases to protect privacy or sensitive...

    Provided By Ohio State University

  • White Papers // Nov 2010

    Measurements on Mobile Phone Wireless Communications

    It is well-known to the research community that the range of Bluetooth class II devices is 10 m. However, the authors have observed that it is at least 20 m for device and service discovery. To better understand this observation, they perform extensive experiments to test Bluetooth communications. They implement...

    Provided By Ohio State University

  • White Papers // Dec 2011

    Femtocell Base Station Deployment in Commercial Buildings: A Global Optimization Approach

    While the deployment of femtocell in residential buildings has firmly positioned it as a major performance leap in wireless communications, its deployment in commercial buildings remains under-explored. In commercial building environments, the femtocell Base Station (FBS) placement planning is particularly challenging due to the impact of the building size, layout,...

    Provided By Ohio State University

  • White Papers // May 2012

    On Wireless Network Infrastructure Optimization for Cyber-Physical Systems in Future Smart Buildings

    Today, most Cyber-Physical Systems (CPS) in smart buildings require a wireless-based network infrastructure for sensing, communication, and actuation. In such CPSs, the energy expenditure and hence battery lifetime of the wireless network infrastructure depend heavily upon the placement of the Base Stations (BS). However, in indoor environments, BS placement is...

    Provided By Ohio State University

  • White Papers // Jan 2012

    A Distributed Newton's Method for Joint Multi-Hop Routing and Flow Control: Theory and Algorithm

    The fast growing scale and heterogeneity of current communication networks necessitate the design of distributed cross-layer optimization algorithms. So far, the standard approach of distributed cross-layer design is based on dual decomposition and the sub-gradient algorithm, which is a first-order method that has a slow convergence rate. In this paper,...

    Provided By Ohio State University

  • White Papers // Jul 2011

    Algorithm Design for Femtocell Base Station Placement in Commercial Building Environments

    Although femtocell deployments in residential buildings have been increasingly prevalent, femtocell deployment in commercial building environments remains in its infancy. One of the main challenges lies in the Femtocell Base Stations (FBS) placement problem, which is complicated by the buildings' size, layout, structure, and floor/wall separations. In this paper, the...

    Provided By Ohio State University

  • White Papers // Jun 2012

    Low-Complexity Optimal Scheduling Over Correlated Fading Channels With ARQ Feedback

    The authors investigate the downlink scheduling problem under Markovian ON/OFF fading channels, where the instantaneous channel state information is not directly accessible, but is revealed via ARQ-type feedback. The scheduler can exploit the temporal correlation/channel memory inherent in the Markovian channels to improve network performance. However, designing low-complexity and throughput-optimal...

    Provided By Ohio State University

  • White Papers // Jan 2012

    Understanding the Signicance of Network Performance in End Applications: A Case Study With EtherFabric and InniBand

    Due to the low speeds of earlier generation networks such as Fast Ethernet, network communication was considered to be one of the primary bottlenecks in cluster computing. Accordingly, researchers used a number of techniques to hide the communication overheads in networks. In order to alleviate this problem, several researchers and...

    Provided By Ohio State University

  • White Papers // Sep 2012

    A High-Fidelity Temperature Distribution Forecasting System for Data Centers

    Data centers have become a critical computing infrastructure in the era of cloud computing. Temperature monitoring and forecasting are essential for preventing over heating induced server shutdowns and improving a data center's energy efficiency. This paper presents a novel cyber-physical approach for temperature forecasting in data centers, which integrates Computational...

    Provided By Ohio State University

  • White Papers // Dec 2012

    Performance of Low-Complexity Greedy Scheduling Policies in Multi-Channel Wireless Networks: Optimal Throughput and Near-Optimal Delay

    In this paper, the authors focus on the scheduling problem in multi-channel wireless networks, e.g., the downlink of a single cell in Fourth Generation (4G) OFDM-based cellular networks. Their goal is to design efficient scheduling policies that can achieve provably good performance in terms of both throughput and delay, at...

    Provided By Ohio State University

  • White Papers // Aug 2009

    Maximizing Aggregated Revenue in Sensor Networks Under Deadline Constraints

    In this paper, the authors have developed a general optimization framework for solving the problem of maximizing revenue in data aggregation trees when a deadline is imposed by the sink. They considered a one-hop interference model and proposed a polynomial time algorithm that uses only local information at each hop...

    Provided By Ohio State University

  • White Papers // Apr 2011

    Maximizing Aggregated Information in Sensor Networks Under Deadline Constraints

    The authors study the problem of maximizing the aggregated information in sensor networks with deadline constraints. The model is that of a sensor network that is arranged in the form of a tree topology, where the root corresponds to the sink node, and the rest of the network detects an...

    Provided By Ohio State University

  • White Papers // Jan 2011

    Peer-to-Peer Spatial Queries in Sensor Networks

    Sensor networks that consist of potentially several thousands of nodes each with sensing (heat, sound, light, magnetism, etc.) and wireless communication capabilities provide great opportunities for monitoring spatial information about a region of interest. Although spatial query execution has been studied extensively in the context of database systems (e.g., indexing...

    Provided By Ohio State University

  • White Papers // Jan 2011

    Structure-Free Data Aggregation in Sensor Networks

    Data aggregation protocols can reduce the communication cost, thereby extending the lifetime of sensor networks. Prior works on data aggregation protocols have focused on tree-based or cluster-based structured approaches. Although structured approaches are suited for data gathering applications, they incur high maintenance overhead in dynamic scenarios for event-based applications. The...

    Provided By Ohio State University

  • White Papers // Dec 2009

    Maximizing the Contact Opportunity for Vehicular Internet Access

    With increasing popularity of media enabled hand-helds, the need for high data-rate services for mobile users is evident. Large-scale Wireless LANs (WLANs) can provide such a service, but they are expensive to deploy and maintain. Open WLAN Access-Points (APs), on the other hand, need no new deployments, but can offer...

    Provided By Ohio State University

  • White Papers // Dec 2009

    Joint Energy Management and Resource Allocation in Rechargeable Sensor Networks

    Energy harvesting sensor platforms have opened up a new dimension to the design of network protocols. In order to sustain the network operation, the energy consumption rate cannot be higher than the energy harvesting rate, otherwise, sensor nodes will eventually deplete their batteries. In contrast to traditional network resource allocation...

    Provided By Ohio State University

  • White Papers // Jan 2011

    Dynamic Forwarding Over Tree-on-DAG for Scalable Data Aggregation in Sensor Networks

    Computing and maintaining network structures for efficient data aggregation incurs high overhead for dynamic events where the set of nodes sensing an event changes with time. Moreover, structured approaches are sensitive to the waiting-time which is used by nodes to wait for packets from their children before forwarding the packet...

    Provided By Ohio State University

  • White Papers // Jan 2011

    On the Potential of Structure-Free Data Aggregation in Sensor Networks

    Data aggregation protocols can reduce the cost of communication, thereby extending the lifetime of sensor networks. Prior work on data aggregation protocols has focused on tree-based or cluster-based structured approaches. Although structured approaches are suited for data gathering applications, they incur high maintenance overhead in dynamic scenarios for event-based applications....

    Provided By Ohio State University

  • White Papers // May 2010

    Delay Analysis and Optimality of Scheduling Policies for Multi-Hop Wireless Networks

    In this paper, the authors analyze the delay performance of a multi-hop wireless network in which the routes between source-destination pairs are fixed. They develop a new queue grouping technique to handle the complex correlations of the service process resulting from the multi-hop nature of the flows and their mutual...

    Provided By Ohio State University

  • White Papers // Dec 2009

    On the Asymptotic Queueing Behavior of General AQM Routers

    In this paper, the authors study the asymptotic behavior of an AQM router serving many AIMD flows. Their model for the AQM router is general and covers most AQM schemes in the current literature. They use a window-based model for the AIMD flows. When the number of AIMD flows is...

    Provided By Ohio State University

  • White Papers // Dec 2010

    Provisioning for Cloud Computing

    The paradigm of cloud computing has started a new era of service computing. While there are many research efforts on developing enabling technologies for cloud computing, few focuses on how to strategically set price and capacity and what key components are leading to success in this emerging market. In this...

    Provided By Ohio State University

  • White Papers // Jul 2011

    Throughput-Optimal Scheduling in Multi-Hop Wireless Networks Without Per-Flow Information

    This paper focuses on designing throughput-optimal scheduling policies that avoid using per-flow or per-destination information, maintain a single data queue for each link, and exploit only local information, for multi-hop wireless networks under general interference constraints. Although the celebrated backpressure algorithm maximizes throughput, it requires per-flow or per-destination information (which...

    Provided By Ohio State University

  • White Papers // Aug 2011

    Scaling Laws and Design Principles for Multi-Cellular Wireless OFDMA Systems

    In this paper, the authors consider the downlink of large-scale multi-cellular OFDMA-based networks and study performance bounds of the system as a function of the number of users K, the number of base-stations B, and the number of resource blocks N. Here, a resource block is a collection of subcarriers...

    Provided By Ohio State University

  • White Papers // Mar 2011

    Optimal Power Allocation in Multi-Hop Wireless Networks With Finite Buffers

    With expanding wireless applications and increasing demand for wireless data rates, it is significant to develop power control algorithms that take maximum advantage of available capacity while satisfying certain Quality of Service (QoS) requirements such as minimum data rate and end-to-end delay constraints. Recently, back-pressure algorithm and its extensions have...

    Provided By Ohio State University

  • White Papers // Jan 2011

    Guaranteed Opportunistic Scheduling in Multi-Hop Cognitive Radio Networks

    Cognitive radio networks enable opportunistic sharing of bandwidth/spectrum. In this paper, the authors introduce optimal control and scheduling algorithms for multi-hop cognitive radio networks to maximize the throughput of secondary users while stabilizing the cognitive radio network subject to collision rate constraints required by primary users. They show that by...

    Provided By Ohio State University

  • White Papers // Dec 2009

    Communication Over Doubly Selective Channels: Efficient Equalization and Max-Diversity Precoding

    The authors consider the problem of practical communication over a Doubly Selective (DS) channel, i.e., a time and frequency selective channel. The problem is approached in two different ways: coherent communication and non-coherent communication, and for each communication scheme they propose practical and near-optimal equalizers and maximum-diversity precoders. Toward these...

    Provided By Ohio State University

  • White Papers // Apr 2011

    Asymptotically Tight Steady-State Queue Length Bounds Implied by Drift Conditions

    The Foster-Lyapunov theorem and its variants serve as the primary tools for studying the stability of queueing systems. In addition, it is well known that setting the drift of the Lyapunov function equal to zero in steady-state provides bounds on the expected queue lengths. However, such bounds are often very...

    Provided By Ohio State University

  • White Papers // Nov 2011

    Expectation-Maximization Bernoulli-Gaussian Approximate Message Passing

    In this paper, the authors navigate the space between these two extremes by modeling the signal as i.i.d Bernoulli-Gaussian (BG) with unknown prior sparsity, mean, and variance, and the noise as zero-mean Gaussian with unknown variance, and they simultaneously reconstruct the signal while learning the prior signal and noise parameters....

    Provided By Ohio State University

  • White Papers // Nov 2011

    Full-Duplex Bidirectional MIMO: Achievable Rates Under Limited Dynamic Range

    In this paper, the authors consider the problem of full-duplex bidirectional communication between a pair of modems, each with multiple transmit and receive antennas. The principal difficulty in implementing such a system is that, due to the close proximity of each modem's transmit antennas to its receive antennas, each modem's...

    Provided By Ohio State University

  • White Papers // Feb 2011

    Optimal Resource Allocation in OFDMA Downlink Systems With Imperfect CSI

    In this paper, the authors address the problem of joint scheduling and resource allocation in the downlink of an Orthogonal Frequency Division Multiple Access (OFDMA)-based wireless network when the per-user SNR is known only in distribution. In particular, they consider sum-utility maximization over user schedules, powers, and code rates, subject...

    Provided By Ohio State University

  • White Papers // Jul 2011

    Can Voluntary Programs Resolve China's Environmental Crisis? An Analysis Of ISO 14001 Certification In A Sample Of Chinese Firms

    China's rapid economic growth has been accompanied by rapid environmental degradation. China is currently the largest producer of greenhouse gasses in the world. China is also home to 20 of the 30 most polluted cities in the world. Weak federal oversight leads to poor enforcement of environmental regulations at the...

    Provided By Ohio State University

  • White Papers // Feb 2011

    Private Equity In The 21st Century: Cash Flows, Performance, And Contract Terms From 1984-2010

    Using detailed data on the quarterly cash flows and management contracts for a large sample of private equity funds from 1984-2010, the authors investigate the behavior of private equity cash flows, the determinants of contractual terms, including General Partner (GP) compensation and capital commitments, and the relation between contractual terms...

    Provided By Ohio State University

  • White Papers // Jan 2009

    A Tale Of Two Anomalies: The Implications Of Investor Attention For Price And Earnings Momentum

    The authors examine the role of investor attention in explaining the profitability of price and earnings momentum strategies. Using trading volume and market state to measure cross-sectional and time-series variations of investor attention, they find that price momentum profits are higher among high volume stocks and in up markets, but...

    Provided By Ohio State University