University of Peloponnese

Displaying 1-40 of 47 results

  • White Papers // Apr 2014

    Coherent Causal Memory

    Coherent Causal Memory (CCM) is causal memory in which prefixes of an execution can be mapped to global memory states in a consistent way. While CCM requires conflicting pairs of writes to be globally ordered, it allows writes to remain unordered with respect to both reads and non-conflicting writes. Nevertheless,...

    Provided By University of Peloponnese

  • White Papers // Jan 2014

    Let SDN Be Your Eyes: Secure Forensics in Data Center Networks

    Discovering the causes of incorrect behavior in large networks is often difficult. This difficulty is compounded when some machines in the network are compromised, since these compromised machines may use deception or tamper with data to frustrate forensic analysis. Recently proposed forensic tools enable administrators to learn the causes of...

    Provided By University of Peloponnese

  • White Papers // Dec 2013

    Elliptic Curve Cryptography in Practice

    In this paper, the authors perform a review of Elliptic Curve Cryptography (ECC), as it is used in practice today, in order to reveal unique mistakes and vulnerabilities that arise in implementations of ECC. They study four popular protocols that make use of this type of public-key cryptography: bitcoin, Secure...

    Provided By University of Peloponnese

  • White Papers // Aug 2013

    Distributed Time-Aware Provenance

    The ability to reason about changes in a distributed system's state enables network administrators to better diagnose protocol mis-configurations, detect intrusions, and pinpoint performance bottlenecks. The authors propose a novel provenance model called Distributed Time-aware Provenance (DTaP) that aids forensics and debugging in distributed systems by explicitly representing time, distributed...

    Provided By University of Peloponnese

  • White Papers // Aug 2013

    PROPOLIS: Provisioned Analysis of DataCentric Processes

    In this paper, the authors consider the analysis of data-centric process-based applications, namely applications that depend on an underlying database and whose control is guided by a finite state transition system. They observe that analysts of such applications often want to do more than analyze a specific instance of the...

    Provided By University of Peloponnese

  • White Papers // May 2013

    AutoTune: Optimizing Execution Concurrency and Resource Usage in MapReduce Workflows

    An increasing number of MapReduce applications are written using high-level SQL-like abstractions on top of MapReduce engines. Such programs are translated into MapReduce workflows where the output of one job becomes the input of the next job in a workflow. A user must specify the number of reduce tasks for...

    Provided By University of Peloponnese

  • White Papers // Feb 2013

    Performance Modeling of MapReduce Jobs in Heterogeneous Environments

    While a traditional Hadoop cluster deployment assumes a homogeneous cluster, many enterprise clusters are grown incrementally over time, and might have a variety of different servers in the cluster. The nodes' heterogeneity represents an additional challenge for efficient cluster and job management. Due to resource heterogeneity it is often unclear...

    Provided By University of Peloponnese

  • White Papers // Jan 2013

    Throughput Guarantees Through Maximal Scheduling in Wireless Networks

    The authors address the question of providing throughput guarantees through distributed scheduling, which has remained an open problem for some time. They consider a simple distributed scheduling strategy, maximal scheduling, and prove that it attains a guaranteed fraction of the maximum throughput region in arbitrary wireless networks. The guaranteed fraction...

    Provided By University of Peloponnese

  • White Papers // Jan 2013

    A Scalable, Low-Overhead Rate Control Algorithm for Multirate Multicast Sessions

    In multi-rate multicasting, different users (receivers) within the same multicast group can receive service at different rates, depending on the user requirements and the network congestion level. Compared to unirate multicasting, this provides more flexibility to the user, and allows more efficient usage of the network resources. In this paper,...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    Towards Dynamic Pricing-Based Collaborative Optimizations for Green Data Centers

    Increased demand for cloud computing services has ushered power management schemes into the frontlines of data center research. Meanwhile, market penetration of intermittent renewable energy sources (e.g., wind and solar) is on the rise. While clean and abundant, their intermittency is troubling for utility companies, requiring power balancing reserves to...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    Getting More for Less in Optimized MapReduce Workflows

    Big data requires new technologies to process large quantities of data in scalable, efficient, and cost-effective way. As digital convergence leads to new sources of data and as the cost of data storage is decreasing, the businesses are exploiting the MapReduce paradigm and its open-source implementation Hadoop as a platform...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    A Propagation Model for Provenance Views of Public/Private Workflows

    The authors explain the problem of concealing functionality of a proprietary or private module when provenance information is shown over repeated executions of a workflow which contains both public and private modules. They show that G-privacy cannot be achieved simply by combining solutions for individual private modules; data hiding must...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    Exploiting Metric Structure for Efficient Private Query Release

    The authors consider the problem of privately answering queries defined on databases which are collections of points belonging to some metric space. They give simple, computationally efficient algorithms for answering distance queries defined over an arbitrary metric. Distance queries are specified by points in the metric space, and ask for...

    Provided By University of Peloponnese

  • White Papers // Oct 2012

    Simple and Nearly Optimal Multi-Item Auctions

    The authors provide a Polynomial Time Approximation Scheme (PTAS) for the Bayesian optimal multiitem multi-bidder auction problem under two conditions. First, bidders are independent, have additive valuations and are from the same population. Second, every bidder's value distributions of items are independent but not necessarily identical Monotone Hazard Rate (MHR)...

    Provided By University of Peloponnese

  • White Papers // Oct 2012

    Scalable Network Virtualization in Software-Defined Networks

    Network virtualization gives each \"Tenant\" in a data center its own network topology and control over the flow of its traffic. By offering a standard interface between controller applications and switch forwarding tables, Software Defined Networking (SDN) is a natural platform for network virtualization. Yet, supporting a large number of...

    Provided By University of Peloponnese

  • White Papers // Sep 2012

    Extending Task-Level to Job-Level Fixed Priority Assignment and Schedulability Analysis Using Pseudo-Deadlines

    In global real-time multiprocessor scheduling, a recent analysis technique for Task-level Fixed-Priority (TFP) scheduling has been shown to outperform many of the analyses for Job-level Fixed-Priority (JFP) scheduling on average. Since JFP is a generalization of TFP scheduling, and the TFP analysis technique itself has been adapted from an earlier...

    Provided By University of Peloponnese

  • White Papers // May 2012

    First Passage Time Problems With Applications to Synchronization

    First passage time problems arise in many fields, but few of them are explicitly solved. Motivated by an application to synchronization of clocks, this paper obtains the probability distribution for the first passage time for a Brownian motion with quadratic drift to exit from two constant barriers that are not...

    Provided By University of Peloponnese

  • White Papers // Apr 2012

    Watchdog: Hardware for Safe and Secure Manual Memory Management and Full Memory Safety

    Languages such as C and C++ use unsafe manual memory management, allowing simple bugs (i.e., accesses to an object after de-allocation) to become the root cause of exploitable security vulnerabilities. This paper proposes Watchdog, a hardware-based approach for ensuring safe and secure manual memory management. Inspired by prior software-only proposals,...

    Provided By University of Peloponnese

  • White Papers // Mar 2012

    Reliable Client Accounting for P2P-Infrastructure Hybrids

    Content Distribution Networks (CDNs) have started to adopt hybrid designs, which employ both dedicated edge servers and resources contributed by clients. Hybrid designs combine many of the advantages of infrastructure based and Peer-To-Peer systems, but they also present new challenges. This paper identifies reliable client accounting as one such challenge....

    Provided By University of Peloponnese

  • White Papers // Feb 2012

    Optimizing Completion Time and Resource Provisioning of Pig Programs

    As cloud computing continues to mature, IT managers have started concentrating on the support of additional performance requirements: quality of service and tailored resource allocation for achieving service performance goals. In this paper, the authors consider the popular Pig framework that provides a high-level SQL-like abstraction on top of MapReduce...

    Provided By University of Peloponnese

  • White Papers // Jan 2012

    Realizing Compositional Scheduling through Virtualization

    The authors present a co-designed scheduling framework and platform architecture that together support compositional scheduling of real-time systems. The architecture is built on the Xen virtualization platform, and relies on compositional scheduling theory that uses periodic resource models as component interfaces. They implement resource models as periodic servers and consider...

    Provided By University of Peloponnese

  • White Papers // Dec 2011

    Why On-Chip Cache Coherence is Here to Stay

    Today's multicore chips commonly implement shared memory with cache coherence as low-level support for operating systems and application software. Technology trends continue to enable the scaling of the number of (processor) cores per chip. Because conventional wisdom says that the coherence does not scale well to many cores, some prognosticators...

    Provided By University of Peloponnese

  • White Papers // Nov 2011

    An Empirical Analysis of Scheduling Techniques for Real-Time Cloud-Based Data Processing

    In this paper, the authors explore the challenges and needs of current cloud infrastructures, to better support cloud-based data-intensive applications that are not only latency-sensitive but also require strong timing guarantees. These applications have strict deadlines and deadline misses are undesirable. To highlight the challenges in this paper, they provide...

    Provided By University of Peloponnese

  • White Papers // Sep 2011

    The Dark Energy Survey Data Management System

    The Dark Energy Survey (DES) is a project with the goal of building, installing and exploiting a new 74 CCD- camera at the Blanco telescope, in order to study the nature of cosmic acceleration. The DES data management system has been designed for the processing, calibration and archiving of these...

    Provided By University of Peloponnese

  • White Papers // Sep 2011

    Towards the Effective Temporal Association Mining of Spam Blacklists

    IP blacklists are a well-regarded anti-spam mechanism that captures global spamming patterns. These properties make such lists a practical ground-truth by which to study email spam behaviors. Observing one blacklist for nearly a year-and-a-half, the authors collected data on roughly half a billion listing events. In this paper, that data...

    Provided By University of Peloponnese

  • White Papers // Jul 2011

    Fighting Cybercrime with Packet Attestation

    IP source addresses are often the only initial lead when investigating cybercrime in the Internet. Unfortunately, source addresses are easily forged, which can protect the culprits and lead to false accusations. The authors describe a new method for packet attestation in the Internet. Packet attestation establishes whether or not a...

    Provided By University of Peloponnese

  • White Papers // May 2011

    Mitigating Spam Using Spatio-Temporal Reputation

    In this paper, the authors present PREventive Spatio-Temporal Aggregation (PRESTA), a reputation model that combines spatial and temporal features to produce values that are behavior predictive and useful in partial-knowledge situations. To evaluate its effectiveness, they applied PRESTA in the domain of spam detection. Studying the temporal properties of IP...

    Provided By University of Peloponnese

  • White Papers // May 2011

    The Business Model: Recent Developments and Future Research

    In this paper, the authors provide a broad and multifaceted review of the received literature on business models in which the authors examine the business model concept through multiple subject matter lenses. The review reveals that scholars do not agree on what a business model is and that the literature...

    Provided By University of Peloponnese

  • White Papers // May 2011

    Maiorana-McFarland Functions With High Second-Order Nonlinearity

    The second-order non-linearity, and the best quadratic approximations, of Boolean functions are studied in this paper. The authors prove that cubic functions within the Maiorana-McFarland class achieve very high second order non-linearity, which is close to an upper bound that was recently proved by Carlet et al., and much higher...

    Provided By University of Peloponnese

  • White Papers // Apr 2011

    Passive Optical Network Design Optimization for Wireless Backhauling

    The increasing popularity of converged media services is promoting the deployment of a range of broadband networking technologies aiming at serving the increased bandwidth as well as service portability and user mobility demands. To optimally address the above requirements hybrid access network architectures coupling the benefits of optical (high capacity,...

    Provided By University of Peloponnese

  • White Papers // Mar 2011

    Sharing Work in Keyword Search Over Databases

    An important means of allowing non-expert end-users to pose ad hoc queries - whether over single databases or data integration systems - is through keyword search. Given a set of keywords, the query processor finds matches across different tuples and tables. It computes and executes a set of relational sub-queries...

    Provided By University of Peloponnese

  • White Papers // Nov 2010

    SPICE: Spatial Processors Interconnected for Concurrent Execution for Accelerating the SPICE Circuit Simulator Using an FPGA

    Spatial processing of sparse, irregular floating-point computation using a single FPGA enables up to an order of magnitude speedup (mean 2.8x speedup) over a conventional microprocessor for the SPICE circuit simulator. The authors decompose SPICE into its three constituent phases: model-evaluation, sparse matrix-solve, and iteration control and parallelize each phase...

    Provided By University of Peloponnese

  • White Papers // Nov 2010

    Having Your Cake and Eating It Too: Routing Security with Privacy Protections

    Internet Service Providers typically do not reveal details of their inter-domain routing policies due to security concerns, or for commercial or legal reasons. As a result, it is difficult to hold ISPs accountable for their contractual agreements. Existing solutions can check basic properties, e.g., whether route announcements correspond to valid...

    Provided By University of Peloponnese

  • White Papers // Oct 2010

    Real-Time MapReduce Scheduling

    In this paper, the authors explore the feasibility of enabling the scheduling of mixed hard and soft real-time MapReduce applications. They first present an experimental evaluation of the popular Hadoop MapReduce middleware on the Amazon EC2 cloud. Their evaluation reveals tradeoffs between overall system throughput and execution time predictability, as...

    Provided By University of Peloponnese

  • White Papers // Jul 2010

    On the Feasibility of Dynamic Rescheduling on the Intel Distributed Computing Platform

    In this paper, the authors examine the feasibility of dynamic rescheduling techniques for effectively utilizing compute resources within a data center. Their paper is motivated by practical concerns of Intel's NetBatch system, an Internet-scale data center based distributed computing platform developed by Intel Corporation for massively parallel chip simulations within...

    Provided By University of Peloponnese

  • White Papers // Jun 2010

    Business Model Innovation: Creating Value in Times of Change

    The authors highlight business model innovation as a way for general managers and entrepreneurs to create and appropriate value, especially in times of economic change. Business model innovation, which involves designing a modified or new activity system, relies on recombining the existing resources of a firm and its partners, and...

    Provided By University of Peloponnese

  • White Papers // Jan 2010

    Multiprocessor Real-Time Scheduling Considering Concurrency and Urgency

    It has been widely studied how to schedule realtime tasks on multiprocessor platforms. Several studies find optimal scheduling policies for implicit deadline task systems, but it is hard to understand how each policy utilizes the two important aspects of scheduling real-time tasks on multiprocessors: inter-job concurrency and job urgency. In...

    Provided By University of Peloponnese

  • White Papers // Nov 2009

    On Interrupt Scheduling Based on Process Priority for Predictable Real-Time Behavior

    Traditionally, kernel services are of a higher priority than user processes. The kernel can preempt the currently executed process in order to perform interrupt handling for the behalf of another process, even though the latter process is of a lower priority than the former. This can be viewed as priority...

    Provided By University of Peloponnese

  • White Papers // Jul 2009

    Comparative Study of Demand Driven Routing Protocols Over Mobile Ad-Hoc Networks

    In this paper, the authors present a comparative study in a MANET environment. MANET is specifically characterized by high mobility of network nodes and frequent changes of direct visibility. High dynamicity affects the design and implementation of distributed applications by significantly increasing their complexity, to consider not only routing and...

    Provided By University of Peloponnese

  • White Papers // Apr 2009

    Specifying Relaxed Memory Models for State Exploration Tools

    In order to explore programs on relaxed memory model, the authors need to specify the memory models in a way which is compatible with state exploration tools. Memory model specifications typically fall into two categories: axiomatic and operational. Memory models are often specified axiomatically, as a set of constraints on...

    Provided By University of Peloponnese

  • White Papers // Jan 2013

    Throughput Guarantees Through Maximal Scheduling in Wireless Networks

    The authors address the question of providing throughput guarantees through distributed scheduling, which has remained an open problem for some time. They consider a simple distributed scheduling strategy, maximal scheduling, and prove that it attains a guaranteed fraction of the maximum throughput region in arbitrary wireless networks. The guaranteed fraction...

    Provided By University of Peloponnese

  • White Papers // Jan 2013

    A Scalable, Low-Overhead Rate Control Algorithm for Multirate Multicast Sessions

    In multi-rate multicasting, different users (receivers) within the same multicast group can receive service at different rates, depending on the user requirements and the network congestion level. Compared to unirate multicasting, this provides more flexibility to the user, and allows more efficient usage of the network resources. In this paper,...

    Provided By University of Peloponnese

  • White Papers // Jul 2011

    Fighting Cybercrime with Packet Attestation

    IP source addresses are often the only initial lead when investigating cybercrime in the Internet. Unfortunately, source addresses are easily forged, which can protect the culprits and lead to false accusations. The authors describe a new method for packet attestation in the Internet. Packet attestation establishes whether or not a...

    Provided By University of Peloponnese

  • White Papers // Mar 2012

    Reliable Client Accounting for P2P-Infrastructure Hybrids

    Content Distribution Networks (CDNs) have started to adopt hybrid designs, which employ both dedicated edge servers and resources contributed by clients. Hybrid designs combine many of the advantages of infrastructure based and Peer-To-Peer systems, but they also present new challenges. This paper identifies reliable client accounting as one such challenge....

    Provided By University of Peloponnese

  • White Papers // May 2012

    First Passage Time Problems With Applications to Synchronization

    First passage time problems arise in many fields, but few of them are explicitly solved. Motivated by an application to synchronization of clocks, this paper obtains the probability distribution for the first passage time for a Brownian motion with quadratic drift to exit from two constant barriers that are not...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    Exploiting Metric Structure for Efficient Private Query Release

    The authors consider the problem of privately answering queries defined on databases which are collections of points belonging to some metric space. They give simple, computationally efficient algorithms for answering distance queries defined over an arbitrary metric. Distance queries are specified by points in the metric space, and ask for...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    A Propagation Model for Provenance Views of Public/Private Workflows

    The authors explain the problem of concealing functionality of a proprietary or private module when provenance information is shown over repeated executions of a workflow which contains both public and private modules. They show that G-privacy cannot be achieved simply by combining solutions for individual private modules; data hiding must...

    Provided By University of Peloponnese

  • White Papers // Jan 2012

    Realizing Compositional Scheduling through Virtualization

    The authors present a co-designed scheduling framework and platform architecture that together support compositional scheduling of real-time systems. The architecture is built on the Xen virtualization platform, and relies on compositional scheduling theory that uses periodic resource models as component interfaces. They implement resource models as periodic servers and consider...

    Provided By University of Peloponnese

  • White Papers // Jan 2014

    Let SDN Be Your Eyes: Secure Forensics in Data Center Networks

    Discovering the causes of incorrect behavior in large networks is often difficult. This difficulty is compounded when some machines in the network are compromised, since these compromised machines may use deception or tamper with data to frustrate forensic analysis. Recently proposed forensic tools enable administrators to learn the causes of...

    Provided By University of Peloponnese

  • White Papers // Jul 2008

    Hierarchical Scheduling Framework for Virtual Clustering of Multiprocessors

    Scheduling of sporadic task systems on multiprocessor platforms is an area which has received much attention in the recent past. It is widely believed that finding an optimal scheduler is hard, and therefore most studies have focused on developing algorithms with good utilization bounds. These algorithms can be broadly classified...

    Provided By University of Peloponnese

  • White Papers // Aug 2013

    Distributed Time-Aware Provenance

    The ability to reason about changes in a distributed system's state enables network administrators to better diagnose protocol mis-configurations, detect intrusions, and pinpoint performance bottlenecks. The authors propose a novel provenance model called Distributed Time-aware Provenance (DTaP) that aids forensics and debugging in distributed systems by explicitly representing time, distributed...

    Provided By University of Peloponnese

  • White Papers // Aug 2013

    PROPOLIS: Provisioned Analysis of DataCentric Processes

    In this paper, the authors consider the analysis of data-centric process-based applications, namely applications that depend on an underlying database and whose control is guided by a finite state transition system. They observe that analysts of such applications often want to do more than analyze a specific instance of the...

    Provided By University of Peloponnese

  • White Papers // Oct 2012

    Scalable Network Virtualization in Software-Defined Networks

    Network virtualization gives each \"Tenant\" in a data center its own network topology and control over the flow of its traffic. By offering a standard interface between controller applications and switch forwarding tables, Software Defined Networking (SDN) is a natural platform for network virtualization. Yet, supporting a large number of...

    Provided By University of Peloponnese

  • White Papers // Feb 2009

    Performance Evaluation of Multicast Routing Over Multilayer Multistage Interconnection Networks

    Multilayer MINs have emerged mainly due to the increased need for routing capacity in the presence of multicast and broadcast traffic, their performance prediction and evaluation however has not been studied sufficiently insofar. In this paper, authors use simulation to evaluate the performance of multilayer MINs with switching elements of...

    Provided By University of Peloponnese

  • White Papers // May 2011

    Maiorana-McFarland Functions With High Second-Order Nonlinearity

    The second-order non-linearity, and the best quadratic approximations, of Boolean functions are studied in this paper. The authors prove that cubic functions within the Maiorana-McFarland class achieve very high second order non-linearity, which is close to an upper bound that was recently proved by Carlet et al., and much higher...

    Provided By University of Peloponnese

  • White Papers // Jul 2009

    Comparative Study of Demand Driven Routing Protocols Over Mobile Ad-Hoc Networks

    In this paper, the authors present a comparative study in a MANET environment. MANET is specifically characterized by high mobility of network nodes and frequent changes of direct visibility. High dynamicity affects the design and implementation of distributed applications by significantly increasing their complexity, to consider not only routing and...

    Provided By University of Peloponnese

  • White Papers // Apr 2011

    Passive Optical Network Design Optimization for Wireless Backhauling

    The increasing popularity of converged media services is promoting the deployment of a range of broadband networking technologies aiming at serving the increased bandwidth as well as service portability and user mobility demands. To optimally address the above requirements hybrid access network architectures coupling the benefits of optical (high capacity,...

    Provided By University of Peloponnese

  • White Papers // Oct 2012

    Simple and Nearly Optimal Multi-Item Auctions

    The authors provide a Polynomial Time Approximation Scheme (PTAS) for the Bayesian optimal multiitem multi-bidder auction problem under two conditions. First, bidders are independent, have additive valuations and are from the same population. Second, every bidder's value distributions of items are independent but not necessarily identical Monotone Hazard Rate (MHR)...

    Provided By University of Peloponnese

  • White Papers // May 2011

    The Business Model: Recent Developments and Future Research

    In this paper, the authors provide a broad and multifaceted review of the received literature on business models in which the authors examine the business model concept through multiple subject matter lenses. The review reveals that scholars do not agree on what a business model is and that the literature...

    Provided By University of Peloponnese

  • White Papers // Jun 2010

    Business Model Innovation: Creating Value in Times of Change

    The authors highlight business model innovation as a way for general managers and entrepreneurs to create and appropriate value, especially in times of economic change. Business model innovation, which involves designing a modified or new activity system, relies on recombining the existing resources of a firm and its partners, and...

    Provided By University of Peloponnese

  • White Papers // Jul 2006

    Privacy APIs: Access Control Techniques to Analyze and Verify Legal Privacy Policies

    There is a growing interest in establishing rules to regulate the privacy of citizens in the treatment of sensitive personal data such as medical and financial records. Such rules must be respected by software used in these sectors. The regulatory statements are somewhat informal and must be interpreted carefully in...

    Provided By University of Peloponnese

  • White Papers // Nov 2010

    Having Your Cake and Eating It Too: Routing Security with Privacy Protections

    Internet Service Providers typically do not reveal details of their inter-domain routing policies due to security concerns, or for commercial or legal reasons. As a result, it is difficult to hold ISPs accountable for their contractual agreements. Existing solutions can check basic properties, e.g., whether route announcements correspond to valid...

    Provided By University of Peloponnese

  • White Papers // Sep 2011

    The Dark Energy Survey Data Management System

    The Dark Energy Survey (DES) is a project with the goal of building, installing and exploiting a new 74 CCD- camera at the Blanco telescope, in order to study the nature of cosmic acceleration. The DES data management system has been designed for the processing, calibration and archiving of these...

    Provided By University of Peloponnese

  • White Papers // Dec 2013

    Elliptic Curve Cryptography in Practice

    In this paper, the authors perform a review of Elliptic Curve Cryptography (ECC), as it is used in practice today, in order to reveal unique mistakes and vulnerabilities that arise in implementations of ECC. They study four popular protocols that make use of this type of public-key cryptography: bitcoin, Secure...

    Provided By University of Peloponnese

  • White Papers // Nov 2007

    Challenges and Opportunities in Deeply Embedded Systems Security

    The advent of low-powered wireless networks of embedded devices has spurred the development of new applications at the interface between the real world and its digital manifestation. A distributed computing platform that can measure properties of the real world, formulate intelligent inferences, and instrument responses, requires a new class of...

    Provided By University of Peloponnese

  • White Papers // May 2011

    Mitigating Spam Using Spatio-Temporal Reputation

    In this paper, the authors present PREventive Spatio-Temporal Aggregation (PRESTA), a reputation model that combines spatial and temporal features to produce values that are behavior predictive and useful in partial-knowledge situations. To evaluate its effectiveness, they applied PRESTA in the domain of spam detection. Studying the temporal properties of IP...

    Provided By University of Peloponnese

  • White Papers // Sep 2011

    Towards the Effective Temporal Association Mining of Spam Blacklists

    IP blacklists are a well-regarded anti-spam mechanism that captures global spamming patterns. These properties make such lists a practical ground-truth by which to study email spam behaviors. Observing one blacklist for nearly a year-and-a-half, the authors collected data on roughly half a billion listing events. In this paper, that data...

    Provided By University of Peloponnese

  • White Papers // Mar 2011

    Sharing Work in Keyword Search Over Databases

    An important means of allowing non-expert end-users to pose ad hoc queries - whether over single databases or data integration systems - is through keyword search. Given a set of keywords, the query processor finds matches across different tuples and tables. It computes and executes a set of relational sub-queries...

    Provided By University of Peloponnese

  • White Papers // Oct 2010

    Real-Time MapReduce Scheduling

    In this paper, the authors explore the feasibility of enabling the scheduling of mixed hard and soft real-time MapReduce applications. They first present an experimental evaluation of the popular Hadoop MapReduce middleware on the Amazon EC2 cloud. Their evaluation reveals tradeoffs between overall system throughput and execution time predictability, as...

    Provided By University of Peloponnese

  • White Papers // Nov 2010

    SPICE: Spatial Processors Interconnected for Concurrent Execution for Accelerating the SPICE Circuit Simulator Using an FPGA

    Spatial processing of sparse, irregular floating-point computation using a single FPGA enables up to an order of magnitude speedup (mean 2.8x speedup) over a conventional microprocessor for the SPICE circuit simulator. The authors decompose SPICE into its three constituent phases: model-evaluation, sparse matrix-solve, and iteration control and parallelize each phase...

    Provided By University of Peloponnese

  • White Papers // Apr 2014

    Coherent Causal Memory

    Coherent Causal Memory (CCM) is causal memory in which prefixes of an execution can be mapped to global memory states in a consistent way. While CCM requires conflicting pairs of writes to be globally ordered, it allows writes to remain unordered with respect to both reads and non-conflicting writes. Nevertheless,...

    Provided By University of Peloponnese

  • White Papers // Dec 2012

    Getting More for Less in Optimized MapReduce Workflows

    Big data requires new technologies to process large quantities of data in scalable, efficient, and cost-effective way. As digital convergence leads to new sources of data and as the cost of data storage is decreasing, the businesses are exploiting the MapReduce paradigm and its open-source implementation Hadoop as a platform...

    Provided By University of Peloponnese

  • White Papers // Feb 2013

    Performance Modeling of MapReduce Jobs in Heterogeneous Environments

    While a traditional Hadoop cluster deployment assumes a homogeneous cluster, many enterprise clusters are grown incrementally over time, and might have a variety of different servers in the cluster. The nodes' heterogeneity represents an additional challenge for efficient cluster and job management. Due to resource heterogeneity it is often unclear...

    Provided By University of Peloponnese

  • White Papers // May 2013

    AutoTune: Optimizing Execution Concurrency and Resource Usage in MapReduce Workflows

    An increasing number of MapReduce applications are written using high-level SQL-like abstractions on top of MapReduce engines. Such programs are translated into MapReduce workflows where the output of one job becomes the input of the next job in a workflow. A user must specify the number of reduce tasks for...

    Provided By University of Peloponnese

  • White Papers // Nov 2011

    An Empirical Analysis of Scheduling Techniques for Real-Time Cloud-Based Data Processing

    In this paper, the authors explore the challenges and needs of current cloud infrastructures, to better support cloud-based data-intensive applications that are not only latency-sensitive but also require strong timing guarantees. These applications have strict deadlines and deadline misses are undesirable. To highlight the challenges in this paper, they provide...

    Provided By University of Peloponnese

  • White Papers // Jul 2010

    On the Feasibility of Dynamic Rescheduling on the Intel Distributed Computing Platform

    In this paper, the authors examine the feasibility of dynamic rescheduling techniques for effectively utilizing compute resources within a data center. Their paper is motivated by practical concerns of Intel's NetBatch system, an Internet-scale data center based distributed computing platform developed by Intel Corporation for massively parallel chip simulations within...

    Provided By University of Peloponnese

  • White Papers // Feb 2012

    Optimizing Completion Time and Resource Provisioning of Pig Programs

    As cloud computing continues to mature, IT managers have started concentrating on the support of additional performance requirements: quality of service and tailored resource allocation for achieving service performance goals. In this paper, the authors consider the popular Pig framework that provides a high-level SQL-like abstraction on top of MapReduce...

    Provided By University of Peloponnese

  • White Papers // Apr 2009

    Specifying Relaxed Memory Models for State Exploration Tools

    In order to explore programs on relaxed memory model, the authors need to specify the memory models in a way which is compatible with state exploration tools. Memory model specifications typically fall into two categories: axiomatic and operational. Memory models are often specified axiomatically, as a set of constraints on...

    Provided By University of Peloponnese

  • White Papers // Dec 2011

    Why On-Chip Cache Coherence is Here to Stay

    Today's multicore chips commonly implement shared memory with cache coherence as low-level support for operating systems and application software. Technology trends continue to enable the scaling of the number of (processor) cores per chip. Because conventional wisdom says that the coherence does not scale well to many cores, some prognosticators...

    Provided By University of Peloponnese

  • White Papers // Dec 2006

    NoSQ: Store-Load Communication without a Store Queue

    In this paper, the authors present NoSQ (No Store Queue), a microarchitecture that performs store-load communication without a store queue and without executing stores in the out-of-order engine. NoSQ implements store-load communication using Speculative Memory Bypassing (SMB), the dynamic short-circuiting of DEF-store-load-USE chains to DEF-USE chains. Whereas previous proposals used...

    Provided By University of Peloponnese