Massachusetts Institute of Technology

Displaying 81-120 of 467 results

  • White Papers // Oct 2011

    A Power Efficient Sensing/Communication Scheme: Joint Source-Channel-Network Coding by Using Compressive Sensing

    The authors propose a joint source-channel-network coding scheme, based on compressive sensing principles, for wireless networks with AWGN channels (that may include multiple access and broadcast), with sources exhibiting temporal and spatial dependencies. Their goal is to provide a reconstruction of sources within an allowed distortion level at each receiver....

    Provided By Massachusetts Institute of Technology

  • White Papers // Sep 2011

    The Reliability Value of Storage in a Volatile Environment

    In this paper, the authors examine the value of storage in securing reliability of a system with uncertain supply and demand, and supply friction. The storage is frictionless as a supply source, but once used, it cannot be filled up instantaneously. The focus application is a power supply network in...

    Provided By Massachusetts Institute of Technology

  • White Papers // Sep 2011

    Whether and Where to Code in the Wireless Relay Channel

    The throughput benefits of random linear network codes have been studied extensively for wire-lined and wireless erasure networks. It is often assumed that all nodes within a network perform coding operations, for minimal centralized control while maximizing the throughput. In energy-constrained systems, however, coding sub-graphs should be chosen to minimize...

    Provided By Massachusetts Institute of Technology

  • White Papers // Sep 2011

    Speeding Multicast by Acknowledgment Reduction Technique (SMART)

    The authors present a novel feedback protocol for wireless broadcast networks that utilize linear network coding. They consider transmission of packets from one source to many receivers over a single-hop broadcast erasure channel. Their method utilizes a predictive model to request feedback only when the probability that all receivers have...

    Provided By Massachusetts Institute of Technology

  • White Papers // Sep 2011

    A Trigger-Based Middleware Cache for ORMs

    Caching is an important technique in scaling storage for high-traffic web applications. Usually, building caching mechanisms involves significant effort from the application developer to maintain and invalidate data in the cache. In this paper, the authors present CacheGenie, a caching middleware which makes it easy for web application developers to...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jul 2011

    The Sender-Excited Secret Key Agreement Model: Capacity Theorems

    The authors consider the fundamental limits of the secret key generation problem when the sources are excited by the sender. In many practical communication settings, the channel may be influenced by the parties involved. Similar to recent works on probing capacity and channels with action-dependent states, their system model captures...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    Experiences In Cyber Security Education: The MIT Lincoln Laboratory Capture-the-Flag Exercise

    Many popular and well-established cyber security Capture The Flag (CTF) exercises are held each year in a variety of settings, including universities and semi-professional security conferences. CTF formats also vary greatly, ranging from linear puzzle-like challenges to team-based offensive and defensive free-for-all hacking competitions. While these events are exciting and...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    A Software Approach to Unifying Multicore Caches

    Multicore chips will have large amounts of fast on-chip cache memory, along with relatively slow DRAM interfaces. The on-chip cache memory, however, will be fragmented and spread over the chip; this distributed arrangement is hard for certain kinds of applications to exploit efficiently, and can lead to needless slow DRAM...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    Asymptotic Interference Alignment for Optimal Repair of MDS codes in Distributed Data Storage

    In distributed storage systems, Maximum Distance Separable (MDS) erasure codes are well-known coding schemes that can offer maximum reliability for a given storage overhead. Consider a scenario where a file of size M is to be stored in n distributed storage nodes. The file is split into k equal parts...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    Probabilistically Accurate Program Transformations

    The standard approach to program transformation involves the use of discrete logical reasoning to prove that the applied transformation does not change the observable semantics of the program. This paper, in contrast, introduces a novel approach that uses probabilistic reasoning to justify transformations that may change the result that the...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    Faster Information Dissemination in Dynamic Networks Via Network Coding

    In this paper, the authors demonstrate that network coding can significantly improve the efficiency of distributed computations in dynamic networks. Network coding breaks with the classical paradigm of routing atomic packets through a network and recognizes that information can be mixed and coded together in ways other (physical) quantities can...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    Rank Minimization Over Finite Fields

    The problem of matrix completion has been well studied in recent years. Essentially, one is given a (small) subset of entries of a low-rank matrix and one is required to estimate all the the remaining entries. In this paper, the authors establish information-theoretic limits in estimating a finite field low-rank...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2011

    On the Geometry of Wireless Network Multicast in 2-D

    The authors provide a geometric solution to the problem of optimal relay positioning to maximize the multicast rate for low-SNR networks. The network they consider consists of a single source, multiple receivers and the only intermediate and locatable node as the relay. They construct network the hypergraph of the system...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2011

    Detecting and Escaping Infinite Loops With Jolt

    Infinite loops can make applications unresponsive. Potential problems include lost work or output, denied access to application functionality, and a lack of responses to urgent events. The authors present Jolt, a novel system for dynamically detecting and escaping infinite loops. At the user's request, Jolt attaches to an application to...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2011

    Manipulating Program Functionality to Eliminate Security Vulnerabilities

    Security vulnerabilities can be seen as excess undesirable functionality present in a software system. The authors present several mechanisms that can either excise or change system functionality in ways that may eliminate security vulnerabilities while, enabling the system to continue to deliver acceptable service. They discuss several automatic techniques for...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2011

    History, Expectations, And Leadership In Evolution Of Cooperation

    The authors study the evolution of the social norm of "Cooperation" in a dynamic environment. Each agent lives for two periods and interacts with agents from the previous and next generations via a coordination game. "History" matters because agents only receive noisy information about the play of the previous generation...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Apr 2011

    The Future of Learning

    In this Webcast, the presenter explains about the future of education. One of the assumptions on which the presenter has built is that the future of education is about learning, not about schooling. The companion assumption is that technology has a critical role to play, not as an end but...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Apr 2011

    Plays Well With Others: Leadership in Online Collaboration

    In this Webcast, the presenter finds the accomplishments of such online collaborations as Wikipedia, Apache and Firefox "Nothing less than astounding," and is both eagerly seeking and hoping to foster the next creative group Internet sensation. The presenter identifies some typical collaborative modes, including the remix (adapting someone else's project);...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Apr 2011

    Technology: Do Kids Need More or Less?

    The ultimate questions for this Sandbox 2011 panel, posed by the presenter, are "Where is technology not working? When is technology not the answer?" That's a bold agenda for a panel of children's media creators and a roomful of other producers in the industry, from Sesame Workshop, WGBH, 360 Kid,...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Apr 2011

    Learning 3.0: Why Technology Belongs in Every Classroom

    The Obama Administration's recently unveiled plan for transforming American education through technology does not envision "Plugging kids in and making them smarter," declares the presenter. Instead, it focuses on leveraging aspects of digital technology "To create way more compelling environments in schools," and to address educational inequities and the larger...

    Provided By Massachusetts Institute of Technology

  • White Papers // Apr 2011

    Gasping for AIR - Why We Need Linked Rules and Justifications on the Semantic Web

    The Semantic Web is a distributed model for publishing, utilizing and extending structured information using Web protocols. One of the main goals of this technology is to automate the retrieval and integration of data and to enable the inference of interesting results. This automation requires logics and rule languages that...

    Provided By Massachusetts Institute of Technology

  • White Papers // Apr 2011

    Exact Distance Oracles for Planar Graphs

    A fast shortest-path query data structure may be of use whenever an application needs to compute shortest path distances between some but not all pairs of nodes. Indeed, shortest-path query processing is an integral part of many applications, in particular in Geographic Information Systems (GIS) and intelligent transportation systems. These...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Apr 2011

    Business and Economics

    Even the most sophisticated technology and computational methods may not be enough to prevent the kind of disastrous errors that recently played out across the global economy, suggest these two speakers. Human temperament and judgment will remain critical factors in financial markets.

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Remote Oblivious Storage: Making Oblivious RAM Practical

    Remote storage of data has become an increasingly attractive and advantageous option, especially due to cloud systems. While encryption protects the data, it does not hide the access pattern to the data. A natural solution is to access remote storage using an Oblivious RAM (ORAM) which provably hides all access...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Robust Distributed Routing in Dynamical Flow Networks - Part I: Locally Responsive Policies and Weak Resilience

    Robustness of distributed routing policies is studied for dynamical flow networks, with respect to adversarial disturbances that reduce the link flow capacities. A dynamical flow network is modeled as a system of ordinary differential equations derived from mass conservation laws on a directed acyclic graph with a single origin-destination pair...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Mar 2011

    Data-Driven Traffic Modeling, Prediction, and Planning

    Some professors work primarily in labs and others mainly at desks. Presenter conducts her research on the bustling streets of Singapore, where she is helping to design a "Future mobility project" Whose goal is to "Marry information technology with the transportation industry."

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    BOOM: Broadcast Optimizations for On-Chip Meshes

    Future many-core chips will require an on-chip network that can support broadcasts and multicasts at good power-performance. A vanilla on-chip network would send multiple unicast packets for each broadcast packet, resulting in latency, throughput and power overheads. Recent research in on-chip multicast support has proposed forking of broadcast/multicast packets within...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Fully Leakage-Resilient Signatures

    A signature scheme is fully leakage resilient (Katz and Vaikuntanathan, ASIACRYPT '09) if it is existentially unforgeable under an adaptive chosen-message attack even in a setting where an adversary may obtain bounded (yet arbitrary) leakage information on all intermediate values that are used throughout the lifetime of the system. This...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Fleets: Scalable Services in a Factored Operating System

    Current monolithic operating systems are designed for uniprocessor systems, and their architecture reflects this. The rise of multicore and cloud computing is drastically changing the tradeoffs in operating system design. The culture of scarce computational resources is being replaced with one of abundant cores, where spatial layout of processes supplants...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Deterministic Network Model Revisited: An Algebraic Network Coding Approach

    The capacity of multiuser networks has been a longstanding problem in information theory. Recently, Avestimehr et al. have proposed a deterministic network model to approximate multiuser wireless networks. This model, known as the ADT network model, takes into account the broadcast nature of wireless medium and interference. The authors show...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Sample Complexity for Topology Estimation in Networks of LTI Systems

    In this paper, the authors propose a consistent and computationally efficient FFT-based algorithm for inferring the network topology where each node in the network is associated to a widesense stationary, ergodic, Gaussian process. Each edge of the tree network is characterized by a linear, time-invariant dynamical system and additive white...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Improving Wireless Network Performance Using Sensor Hints

    With the proliferation of mobile wireless devices such as smartphones and tablets that are used in a wide range of locations and movement conditions, it has become important for wireless protocols to adapt to different settings over short periods of time. Network protocols that perform well in static settings where...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Accurate, Low-Energy Trajectory Mapping for Mobile Devices

    CTrack is an energy-efficient system for trajectory mapping using raw position tracks obtained largely from cellular base station fingerprints. Trajectory mapping, which involves taking a sequence of raw position samples and producing the most likely path followed by the user, is an important component in many location based services including...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    When Both Transmitting and Receiving Energies Matter: An Application of Network Coding in Wireless Body Area Networks

    A network coding scheme for practical implementations of wireless body area networks is presented, with the objective of providing reliability under low-energy constraints. The authors propose a simple network layer protocol for star networks, adapting redundancy based on both transmission and reception energies for data and control packets, as well...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    Decomposing Broadcast Algorithms Using Abstract MAC Layers

    In much of the theoretical literature on global broadcast algorithms for wireless networks, issues of message dissemination are considered together with issues of contention management. This combination leads to complicated algorithms and analysis, and makes it difficult to extend the work to more difficult communication problems. In this paper, the...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    Optimality of Network Coding in Packet Networks

    The authors resolve the question of optimality for a well studied packetized implementation of random linear network coding, called PNC. In PNC, in contrast to the classical memory-less setting, nodes store received information in memory to later produce coded packets that reflect this information. PNC is known to achieve order...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    One Packet Suffices - Highly Efficient Packetized Network Coding with Finite Memory

    Random Linear Network Coding (RLNC) has emerged as a powerful tool for robust high-throughput multicast. Projection analysis, a recently introduced technique, shows that the distributed packetized RLNC protocol achieves (order) optimal and perfectly pipelined information dissemination in many settings. In the original approach to RNLC intermediate nodes code together all...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    SoftCast: Clean-Slate Scalable Wireless Video

    Video broadcast and mobile video challenge the conventional wireless design. In broadcast and mobile scenarios the bit rate supported by the channel differs across receivers and varies quickly over time. The conventional design however forces the source to pick a single bit rate and degrades sharply when the channel cannot...

    Provided By Massachusetts Institute of Technology

  • Webcasts // Feb 2011

    The Fruits Of Diversity

    In a webcast the authors offers a bounty of visual and aural pleasures, a museum curator and two artists describe how their work "Dissolves boundaries," in the words of moderator, often "Leading to new frontiers."

    Provided By Massachusetts Institute of Technology

  • Webcasts // Feb 2011

    Excellence Is A Shared Path: Student Remarks

    In their brief remarks honoring the legacy of Dr. Martin Luther King, Jr., two students strike the theme of collaboration. They touch on the importance of humility and listening to one's inner voice while pursuing a shared vision of justice and equality.

    Provided By Massachusetts Institute of Technology

  • White Papers // Aug 2009

    Caching in Wireless Networks

    The authors consider the problem of delivering content cached in a wireless network of n nodes randomly located on a square of area n. They provide an inner bound on this caching capacity region, and, in the high path-loss regime, a matching (in the scaling sense) outer bound. For large...

    Provided By Massachusetts Institute of Technology

  • White Papers // Oct 2011

    Energy-Efficient Time-Stampless Adaptive Nonuniform Sampling

    Now-a-days, since more and more battery-operated devices are involved in applications with continuous sensing, development of efficient sampling mechanisms is an important issue for these applications. In this paper, the authors investigate power efficiency aspects of a recently proposed adaptive non-uniform sampling. This sampling scheme minimizes the energy consumption of...

    Provided By Massachusetts Institute of Technology

  • White Papers // Oct 2011

    A Power Efficient Sensing/Communication Scheme: Joint Source-Channel-Network Coding by Using Compressive Sensing

    The authors propose a joint source-channel-network coding scheme, based on compressive sensing principles, for wireless networks with AWGN channels (that may include multiple access and broadcast), with sources exhibiting temporal and spatial dependencies. Their goal is to provide a reconstruction of sources within an allowed distortion level at each receiver....

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    Optimality of Network Coding in Packet Networks

    The authors resolve the question of optimality for a well studied packetized implementation of random linear network coding, called PNC. In PNC, in contrast to the classical memory-less setting, nodes store received information in memory to later produce coded packets that reflect this information. PNC is known to achieve order...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2012

    Network Coding With Association Policies in Heterogeneous Networks

    The authors focus on implementing a modified TCP/IP protocol stack by positioning network coding functionalities in the form of a new layer in between the transport and the network layer, thereby allowing incremental deployment. They implement this proposed modification for the TCP/IP stack in the OPNET Modeler and analyze implemented...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2011

    One Packet Suffices - Highly Efficient Packetized Network Coding with Finite Memory

    Random Linear Network Coding (RLNC) has emerged as a powerful tool for robust high-throughput multicast. Projection analysis, a recently introduced technique, shows that the distributed packetized RLNC protocol achieves (order) optimal and perfectly pipelined information dissemination in many settings. In the original approach to RNLC intermediate nodes code together all...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2012

    Optimal Routing and Scheduling for a Simple Network Coding Scheme

    The authors consider jointly optimal routing, scheduling, and network coding strategies to maximize throughput in wireless networks. While routing and scheduling techniques for wireless networks have been studied for decades, network coding is a relatively new technique that allows for an increase in throughput under certain topological and routing conditions....

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2012

    Network Coding for Robust Wireless Networks

    Wireless networks and communications promise to allow improved access to services and information, ubiquitous connectivity, and mobility. However, current wireless networks are not well-equipped to meet the high bandwidth and strict delay requirements of future applications. Wireless networks suffer from frequent losses and low throughput. The authors aim to provide...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jul 2012

    Equivalent Models for Multi-Terminal Channels

    The recently introduced network equivalence results are used to create bit-pipe models that can replace multi-terminal channels within a discrete memoryless network. The goal is to create a set of simple "Components" or "Blocks" that can be substituted for the channel in such a way that the resulting network is...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jul 2012

    Optimality of Network Coding with Buffers

    The authors analyze distributed and Packetized implementations of random linear Network Coding (PNC) with buffers. In these protocols, nodes store received packets to later produce coded packets that reflect this information. They show the optimality of PNC for any buffer size; i.e., they show that PNC performs at least as...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jul 2012

    A Converse for the Wideband Relay Channel with Physically Degraded Broadcast

    The authors investigate the multipath fading relay channel in the limit of a large bandwidth, and in the non-coherent setting, where the channel state is unknown to all terminals, including the relay and the destination. They derive a lower bound on the capacity by proposing and analyzing a peaky frequency...

    Provided By Massachusetts Institute of Technology

  • White Papers // Aug 2010

    On the Performance of Network Coding in Multi-Resolution Wireless Video Streaming

    Scalable video can be used to provide video streaming reliably to a heterogeneous set of receivers with different subscription levels. However, the performance of such schemes can be highly affected by scheduling constraints and unreliable feedback. Network coding, on the other hand, has been shown to reduce scheduling and prioritization...

    Provided By Massachusetts Institute of Technology

  • White Papers // Aug 2009

    Bandwidth Extension of Low Noise Fractional-N Synthesizers

    In this paper, the authors examine issues with extending the bandwidth of fractional-N synthesizers. Quantization noise is shown to be the limiting factor in state-of-the-art fractional-N synthesis. A re-framing of the noise model used to analyze synthesizer phase noise leads directly to a methodology to enable high bandwidth synthesis. They...

    Provided By Massachusetts Institute of Technology

  • White Papers // Oct 2010

    Survivable Network Design Problems in Wireless Networks

    Survivable network design is an important suite of algorithmic problems where the goal is to select a minimum cost network subject to the constraint that some desired connectivity property has to be satisfied by the network. Traditionally, these problems have been studied in a model where individual edges (and sometimes...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2013

    On Analyzing and Improving COPE Performance

    COPE is a new architecture for unicasts in wireless mesh networks that employs opportunistic network coding to improve total throughput. Katti et al. showed through experiments that this system significantly improves the throughput of wireless networks with UDP traffic, and several attempts have been made to analyze the COPE performance....

    Provided By Massachusetts Institute of Technology

  • White Papers // Apr 2012

    Random Access Compressed Sensing Over Fading and Noisy Communication Channels

    Random Access Compressed Sensing (RACS) is an efficient method for data gathering from a network of distributed sensors with limited resources. RACS relies on integrating random sensing with the communication architecture, and achieves overall efficiency in terms of the energy per bit of information successfully delivered. To address realistic deployment...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2012

    On Reliability Functions for Single-Message Unequal Error Protection

    Single-message Unequal Error Protection (UEP) is a channel coding scheme that protects one special message differently from other (regular) messages. This induces three different types of errors in the system: miss (where the authors decode the special codeword as a regular codeword), false alarm (where they decode a regular codeword...

    Provided By Massachusetts Institute of Technology

  • White Papers // Dec 2012

    Saddle Point in the Minimax Converse for Channel Coding

    A mini-max meta-converse has recently been proposed as a simultaneous generalization of a number of classical results and a tool for the non-asymptotic analysis. In this paper it is shown that the order of optimizing the input and output distributions can be interchanged without affecting the bound. In the course...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2013

    Quasi-Static SIMO Fading Channels at Finite Blocklength

    The authors investigate the maximal achievable rate for a given block-length and error probability over quasi-static Single-Input Multiple-Output (SIMO) fading channels. Under mild conditions on the channel gains, it is shown that the channel dispersion is zero regardless of whether the fading realizations are available at the transmitter and/or the...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2012

    Diversity Versus Channel Knowledge at Finite Block-Length

    The authors study the maximal achievable rate for a given block-length n and block error probability over Rayleigh block-fading channels in the non-coherent setting and in the finite block-length regime. Their results show that for a given block-length and error probability, is not monotonic in the channel's coherence time, but...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jul 2012

    The Adversarial Joint Source-Channel Problem

    This paper introduces the problem of joint source-channel coding in the setup where channel errors are adversarial and the distortion is worst case. Unlike the situation in the case of stochastic source-channel model, the separation principle does not hold in adversarial setup. This surprising observation demonstrates that designing good distortion-correcting...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2012

    On Asynchronous Capacity and Dispersion

    Recently Tchamkerten et al. proposed a mathematical formulation of the problem of joint synchronization and error-correction in noisy channels. A variation of their formulation in this paper considers a strengthened requirement that the decoder estimate both the message and the location of the codeword exactly. It is shown that the...

    Provided By Massachusetts Institute of Technology

  • White Papers // May 2010

    Learning Gaussian Tree Models: Analysis of Error Exponents and Extremal Structures

    The problem of learning tree-structured Gaussian graphical models from independent and identically distributed (i.i.d.) samples is considered. The influence of the tree structure and the parameters of the Gaussian distribution on the learning rate as the number of samples increases is discussed. Specifically, the error exponent corresponding to the event...

    Provided By Massachusetts Institute of Technology

  • White Papers // Mar 2011

    Sample Complexity for Topology Estimation in Networks of LTI Systems

    In this paper, the authors propose a consistent and computationally efficient FFT-based algorithm for inferring the network topology where each node in the network is associated to a widesense stationary, ergodic, Gaussian process. Each edge of the tree network is characterized by a linear, time-invariant dynamical system and additive white...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jul 2011

    The Sender-Excited Secret Key Agreement Model: Capacity Theorems

    The authors consider the fundamental limits of the secret key generation problem when the sources are excited by the sender. In many practical communication settings, the channel may be influenced by the parties involved. Similar to recent works on probing capacity and channels with action-dependent states, their system model captures...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2011

    Rank Minimization Over Finite Fields

    The problem of matrix completion has been well studied in recent years. Essentially, one is given a (small) subset of entries of a low-rank matrix and one is required to estimate all the the remaining entries. In this paper, the authors establish information-theoretic limits in estimating a finite field low-rank...

    Provided By Massachusetts Institute of Technology

  • White Papers // Oct 2010

    Consistent and Efficient Reconstruction of Latent Tree Models

    The authors study the problem of learning a latent tree graphical model where samples are available only from a subset of variables. They propose two consistent and computationally efficient algorithms for learning minimal latent trees, that is, trees without any redundant hidden nodes. Their first algorithm, recursive grouping, builds the...

    Provided By Massachusetts Institute of Technology

  • White Papers // Feb 2010

    Wealth Accumulation And Factors Accounting For Success

    The authors use detailed income, balance sheet, and cash flow statements constructed for households in a long monthly panel in an emerging market economy, and some recent contributions in economic theory, to document and better understand the factors underlying success in achieving upward mobility in the distribution of net worth....

    Provided By Massachusetts Institute of Technology

  • White Papers // Aug 2010

    Immersive Journalism: Immersive Virtual Reality for the First-Person Experience of News

    This paper introduces the concept and discusses the implications of immersive journalism, which is the production of news in a form in which people can gain first person experiences of the events or situation described in news stories. The fundamental idea of immersive journalism is to allow the participant, typically...

    Provided By Massachusetts Institute of Technology

  • White Papers // Aug 2009

    Autonomous Routing Algorithms for Networks With Wide-Spread Failures

    The authors study end-to-end delay performance of different routing algorithms in networks with random failures. Specifically, they compare delay performances of Differential Backlog (DB) and Shortest Path (SP) routing algorithms and show that DB routing outperforms SP routing in terms of throughput when the network is heavily loaded and/or the...

    Provided By Massachusetts Institute of Technology

  • White Papers // Aug 2009

    Lightpath Routing and Capacity Assignment for Survivable IP-Over-WDM Networks

    In IP-over-WDM networks the logical topology consists of a set of lightpaths that are routed on top of the physical fiber topology. Hence a single fiber cut can lead to multiple logical link failures. The authors study the impact of lightpath routing on network survivability and spare capacity requirements. They...

    Provided By Massachusetts Institute of Technology

  • White Papers // Dec 2009

    Scheduling Policies for Single-Hop Networks With Heavy-Tailed Traffic

    The area of control of communication networks is one of the most active and fruitful fields of research in recent years, including several elaborate and interconnected forms of control, such as congestion control, routing, scheduling and power control. Much of the theoretical foundation regarding network stability was laid out in...

    Provided By Massachusetts Institute of Technology

  • White Papers // Sep 2009

    The Impact of Queue Length Information on Buffer Overflow in Parallel Queues

    The authors consider a system consisting of N parallel queues, served by one server. Time is slotted, and the server serves one of the queues in each time slot, according to some scheduling policy. In the first part of the paper, they characterize the buffer overflow exponents and the likeliest...

    Provided By Massachusetts Institute of Technology

  • White Papers // Dec 2009

    Optimal Control of Wireless Networks With Finite Buffers

    Design of low delay wireless networks that optimally utilize the network capacity is one of the most important problems in network theory and engineering. Since the seminal paper of Tassiulas and Ephremides which proposed a joint routing and scheduling algorithm that achieves the maximum network throughput, significant efforts have been...

    Provided By Massachusetts Institute of Technology

  • White Papers // Dec 2009

    Network Reliability With Geographically Correlated Failures

    Fiber-optic networks are vulnerable to natural disasters, such as tornadoes or earthquakes, as well as to physical failures, such as an anchor cutting underwater fiber cables. Such real-world events occur in specific geographical locations and disrupt specific parts of the network. Therefore, the geography of the network determines the effect...

    Provided By Massachusetts Institute of Technology

  • White Papers // Apr 2010

    Minimizing Transmission Energy in Sensor Networks Via Trajectory Control

    Energy optimization is a significant component of Wireless Sensor Network (WSN) design. In this paper the authors consider transmission energy optimization in WSNs where messages are collected by a mobile receiver (collector). The collector is responsible for gathering data messages by choosing the optimal path that minimizes the total transmit...

    Provided By Massachusetts Institute of Technology

  • White Papers // Dec 2009

    Cache Replacement Policies for Multicore Processors

    Almost all of the modern computers use multiple cores, and the number of cores is expected to increase as hardware prices go down, and Moore's law fails to hold. Most of the theoretical algorithmic work so far has focused on the setting where multiple cores are performing the same task....

    Provided By Massachusetts Institute of Technology

  • White Papers // Jan 2011

    Middleboxes No Longer Considered Harmful

    Intermediate network elements, such as Network Address Translators (NATs), firewalls, and transparent caches are now commonplace. The usual reaction in the network architecture community to these so-called middleboxes is a combination of scorn (because they violate important architectural principles) and dismay (because these violations make the Internet less flexible). While...

    Provided By Massachusetts Institute of Technology

  • White Papers // Jun 2010

    Detecting Evolving Patterns of Self-Organizing Networks by Flow Hierarchy Measurement

    Hierarchies occur widely in evolving self-organizing ecological, biological, technological and social networks, but detecting and comparing hierarchies is difficult. Here the authors present a metric and technique to quantitatively assess the extent to which self-organizing directed networks exhibit a flow hierarchy. Flow hierarchy is a commonly observed but theoretically overlooked...

    Provided By Massachusetts Institute of Technology

  • White Papers // Apr 2010

    Arguments for an Information-Centric Internetworking Architecture

    The current Internet architecture focuses on communicating entities, largely leaving aside the information to be exchanged among them. However, trends in communication scenarios show that WHAT is being exchanged becoming more important than WHO are exchanging information. Van Jacobson describes this as moving from interconnecting machines to interconnecting information. Any...

    Provided By Massachusetts Institute of Technology