Synchronization plays an important role in multimedia systems at various levels of abstraction. In this paper, we propose a set of powerful abstractions for controlling and synchronizing continuous media streams in di...
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Synchronization plays an important role in multimedia systems at various levels of abstraction. In this paper, we propose a set of powerful abstractions for controlling and synchronizing continuous media streams in distributed environments, The proposed abstractions are based on a very general computation model, that allows media streams to be processed (i.e. produced, consumed or transformed) by arbitrarily structured networks of linked components, Further, compound components can be composed of existing ones to provide higher levels of abstractions, The clock abstraction is provided to control individual media streams, i.e., streams can be started, paused or scaled by issuing the appropriate clock operations. Clock hierarchies are used to hierarchically group related streams, where each clock in the hierarchy identifies and controls a certain group, or subgroup of streams, Control and synchronization requirements can be expressed in a uniform manner by associating group members with control or sync attributes, An important property of the concept of clock hierarchy is that it can be combined in a natural way with component nesting.
The increasing demand for performance has stimulated the wide adoption of many-core accelerators like IntelR Xeon PhiTMCoprocessor, which is based on Intel’s Many Integrated Core architecture. While many HPC applicat...
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The increasing demand for performance has stimulated the wide adoption of many-core accelerators like IntelR Xeon PhiTMCoprocessor, which is based on Intel’s Many Integrated Core architecture. While many HPC applications running in native mode have been tuned to run efficiently on Xeon Phi, it is still unclear how a managed runtime like JVM performs on such an architecture. In this paper, we present the first measurement study of a set of Java HPC applications on Xeon Phi under JVM. One key obstacle to the study is that there is currently little support of Java for Xeon Phi. This paper presents the result based on the first porting of Open JDK platform to Xeon Phi, in which the Hot Spot virtual machine acts as the kernel execution engine. The main difficulty includes the incompatibility between Xeon Phi ISA and the assembly library of Hotspot *** evaluating the multithreaded Java Grande benchmark suite and our ported Java Phoenix benchmarks, we quantitatively study the performance and scalability issues of JVM on Xeon Phi and draw several conclusions from the study. To fully utilize the vector computing capability and hide the significant memory access latency on the coprocessor, we present a semi-automatic vectorization scheme and software prefetching model in Hot *** with 60 physical cores and tuning, our optimized JVM achieves averagely 2.7 x and 3.5 x speedup compared to Xeon CPU processor by using vectorization and prefetching accordingly. Our study also indicates that it is viable and potentially performance-beneficial to run applications written for such a managed runtime like JVM on Xeon Phi.
Many machine learning and data mining （MLDM] problems like recommendation, topic modeling, and medical diagnosis can be modeled as computing on bipartite graphs. However, inost distributed graph-parallelsystems are ...
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Many machine learning and data mining （MLDM] problems like recommendation, topic modeling, and medical diagnosis can be modeled as computing on bipartite graphs. However, inost distributed graph-parallelsystems are oblivious to the unique characteristics in such graphs and existing online graph partitioning algorithms usually cause excessive repli- cation of vertices as well as significant pressure on network communication. This article identifies the challenges and oppor- tunities of partitioning bipartite graphs for distributed MLDM processing and proposes BiGraph, a set of bipartite-oriented graph partitioning algorithms. BiGraph leverages observations such as the skewed distribution of vertices, discriminated computation load and imbalanced data sizes between the two subsets of vertices to derive a set of optimal graph partition- ing algorithms that result in minimal vertex replication and network communication. BiGraph has been implemented on PowerGraph and is shown to have a performance boost up to 17.75X （from 1.16X） for four typical MLDM algorithnls, due to reducing up to 80% vertex replication, and up to 96% network traffic.
Shot peening (SP) is a widely used surface treatment technique that enhances the mechanical performance of materials, notably improving fatigue resistance by inducing compressive residual stresses (RS) and modifying s...
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We attempted to reproduce the results of experiments related to measuring the conductivity of water with deeply polarized electrodes. As proposed in the original works, the polarized electrodes are sensitive to a high...
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Blockchain is becoming popular as a distributed and reliable ledger which allows distrustful parties to transact safely without trusting third parties. Emerging blockchain systems like Ethereum support smart contracts...
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Blockchain is becoming popular as a distributed and reliable ledger which allows distrustful parties to transact safely without trusting third parties. Emerging blockchain systems like Ethereum support smart contracts where miners can run arbitrary user-defined programs. However, one of the biggest concerns about the blockchain and the smart contract is privacy, since all the transactions on the chain are exposed to the public. In this paper, we present ShadowEth, a system that leverages hardware enclave to ensure the confidentiality of smart contracts while keeping the integrity and availability based on existing public blockchains like Ethereum. ShadowEth establishes a confidential and secure platform protected by trusted execution environment （TEE） off the public blockchain for the execution and storage of private contracts. It only puts the process of verification on the blockchain. We provide a design of our system including a protocol of the cryptographic communication and verification and show the applicability and feasibility of ShadowEth by various case studies. We implement a prototype using the Intel SGX on the Ethereum network and analyze the security and availability of the system.
The domain of a global function is the set of all global states of an execution of a distributed program, We show how to monitor a program in order to determine if there exists a global state in which the sum x(1) + x...
The domain of a global function is the set of all global states of an execution of a distributed program, We show how to monitor a program in order to determine if there exists a global state in which the sum x(1) + x(2) +...+ x(N), exceeds some constant K, where x(i) is defined in process i. We examine the cases where x(i) is an integer variable for N = 2 and where x(i) is a boolean variable for general N, For both cases we provide algorithms, prove their correctness, and analyze their complexity. (C) 1997 Academic Press.
Wireless sensor networks based on highly resource-constrained devices require symmetric cryptography in order to make them secure. Integral to this is the exchange of unique symmetric keys between two devices. In this...
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Unikernel,specializing a minimalistic libOS with an application,is an attractive design for cloud ***,the Achilles’heel of unikernel is the lack of multi-process support,which makes it less flexible and *** applicati...
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Unikernel,specializing a minimalistic libOS with an application,is an attractive design for cloud ***,the Achilles’heel of unikernel is the lack of multi-process support,which makes it less flexible and *** applications rely on the process abstraction to isolate different *** example,Apache with the multi-processing module isolates a request handler in a process to guarantee *** art tackles the problem by simulating multi-process with multiple unikernels,which is incompatible with existing cloud providers and also introduces high *** paper proposes Iso-UniK,a new unikernel design enabling multi-task applications with the support of both functionality and ***-UniK leverages a recent hardware feature,named Intel Memory Protection Key(Intel MPK),to provide lightweight and efficient isolation for multi-process in *** design has three benefits compared with previous ***,Iso-UniK does not need hypervisor support and is thus compatible with existing cloud computing platforms;second,Iso-UniK promises fast system calls with only 45 cycles;last,a process can be isolated with a flexible *** have implemented a prototype based on OSv,a unikernel system supporting unmodified ***-UniK can achieve fast fork operation with only 66μs for multi-process *** evaluation shows that the isolation and multi-process support in Iso-UniK will not damage the applications’performance.
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