Cyclops (cyclic-operations) Tensor Framework (CTF) 1 isa distributed library for tensor contractions. CTF aims toscale high-dimensional tensor contractions done in CoupledCluster calculations on massively-parallel supercomputers.The framework preserves tensor symmetry by subdividingtensors cyclically, producing a highly regular parallel decomposition.The parallel decomposition e ectively hidesany high dimensional structure of tensors reducing the complexityof the distributed contraction algorithm to knownlinear algebra methods for matrix multiplication. We alsodetail the automatic topology-aware mapping framework deployedby CTF, which maps tensors of any dimension andstructure onto torus networks of any dimension. We employ;virtualization to provide completely general mapping support while maintaining perfect load balance. Performance of a preliminary version of CTF on the IBM Blue Gene/P and Cray XE6 supercomputers shows highly ecient weakscaling, demonstrating the viability of our approach.

关键词：分布式库张量；线性代数矩阵乘法；载平衡；细分框架

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Modern datacenters support a large number of applications with diverse performance requirements. These performance requirements are expressed at the application layer as high-level service-level objectives (SLOs). However, large-scale distributed storage systems are unaware of these high-level SLOs. This lack of awareness results in poor performance when workloads from multiple applications are consolidated onto the same storage cluster to increase utilization. In this paper, we argue that because SLOs are expressed at a high level, a high-level control mechanism is required. This is in contrast to existing approaches, which use block- or disk-level mechanisms.These require manual translation of high-level requirements into low-level parameters. We present Frosting,a request scheduling layer on top of a distributed storage system that allows application programmers to specify their high-level SLOs directly. Frosting improves over the state-of-the-art by automatically translating high-level SLOs into internal scheduling parameters and uses feedback control to adapt these parameters to changes in the workload. Our preliminary results demonstrate that our overlay approach can multiplex both latency-sensitive and batch applications to increase utilization, while still maintaining a 100ms 99th percentile latency SLO for latencysensitive clients.

关键词：高级服务水平目标；高级控制机制；低级参数；工作负载

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Android’s permission system is intended to inform users about the risks of installing applications. When a user installs an application,he or she has the opportunity to review the application’s permission requests and cancel the installation if the permissions are excessive or objectionable. We examine whether the Android permission system is effective at warning users. In particular, we evaluate whether Android users pay attention to, understand, and act on permission information during installation. We performed two usability studies:an Internet survey of 308 Android users, and a laboratory study where we interviewed and observed 25 Android users. Study participants displayed low attention and comprehension rates: both the Internet survey and laboratory study found that 17% of people paid attention to permissions during installation, and only 3% of Internet survey respondents could correctly answer all three permission comprehension questions. This indicates that current Android permission warnings do not help most users make correct security decisions.However, a notable minority of users demonstrated both awareness of permission warnings and reasonable rates of comprehension.We present recommendations for improving user attention and comprehension, as well as identify open challenges.

关键词：安卓；网络调查；用户关注；权限；Android

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Reliable and fast builds are essential for rapid turnaroundduring development and testing. Popular existing buildsystems rely on correct manual specification of builddependencies, which can lead to invalid build outputsand nondeterminism. We outline the challenges of developingreliable build systems and explore the designspace for their implementation, with a focus on nondistributed,incremental, parallel build systems. We definea general model for resources accessed by build tasksand show its correspondence to the implementation techniqueof minimum information libraries, APIs that returnno information that the application doesn’t plan touse. We also summarize preliminary experimental results from several prototype build managers.

关键词：构建系统；重点标识；探索设计

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A parallel algorithm has perfect strong scaling if its running time on P processors is linear in 1=P, including all commu-nication costs. Distributed-memory parallel algorithms for matrix multiplication with perfect strong scaling have only recently been found. One is based on classical matrix multi-plication (Solomonik and Demmel, 2011), and one is based on Strassen's fast matrix multiplication (Ballard, Demmel, Holtz, Lipshitz, and Schwartz, 2012). Both algorithms scale perfectly, but only up to some number of processors where the inter-processor communication no longer scales.

关键词：处理器；快速矩阵乘法；通信成本

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Blocked matrix multiplication algorithms such as Cannon's algorithm and SUMMA havea 2-dimensional communication structure. We introduce a generalized 'Split-Dimensional' version of Cannon's algorithm (SD-Cannon) with higher-dimensional and bidirectional communication structure.This algorithm is useful for higher-dimensional torus interconnects that can achieve more injection bandwidth than single-link bandwidth. On a bidirectional torus network of dimension d, SD-Cannon can lower the algorithmic bandwidth cost by a factor of up to d. With rectangular collectives, SUMMA also achieves the lower bandwidth cost but has a higher latency cost. We use Charm++ virtualization to eciently map SD-Cannon on unbalanced and odd-dimensional torus network partitions. Our per-formance study on Blue Gene/P demonstrates that an MPI version of SD-Cannon can exploit multiple communication links and improve performance.

关键词：阻塞矩阵乘法算法；二维通信结构；高维环连接；带宽成本

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Web applications have now become so sophisticated that renderinga typical page may require hundreds of intra-datacenter flows. At the same time, web sites must meet strict page creation deadlines of 200-300ms to satisfy user demands for interactivity.Long-tailed flow completion times make it challenging for web sites to meet these constraints. They are forced to choose between rendering a subset of the complex page, or delay its rendering, thus missing deadlines and sacrificing either quality or responsiveness. Either option leads to potential financial loss.

关键词：Web应用程序；用户交互性；长尾流量完成时间

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This paper presents a study were the Rough Set Theory and Data Mining Technique are applied to the electrical power system. The Data Mining technique classifies the system operation in four possible states: normal, alert, emergency (emergency I and emergency II). The states, that correspond to the normal state can be classified as secure and insecure the remaining ones. In this security studies, the overloads in transmition lines and the violation of the voltage limits are used to classify and rank these contingencies. This technique was applied to the 118IEEE busbar test power network and the results obtained are analyzed. Finally, some conclusions that provide a valuable contribution to the understanding of the power system security analysis are pointed out.

关键词：电力系统；数据挖掘技术

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Time synchronization is required in wireless sensor networks in order to improve its performance. This improvement could be noticed in terms of energy, storage, computation, shared resources or bandwidth. One of the main applications in WSNs has been to decrease the energy consumption. A wireless network can save energy with this feature, but if this synchronization is corrupted, it could cause a worse behavior. Firstly, we will analyze which are the most important time synchronization issues. Then, a secure time synchronization method will be presented for group-based wireless sensor networks to avoid malicious attacks. The synchronization technique is based on a system model for secure intra-group synchronization. This system will use simple messages, where nodes of each group will exchange several parameters like time stamps, groupID, etc. in order to make a secure system. The system proposed has high scalability, due to group-based feature, while saves energy thanks to the designed synchronization technique. In order to test our proposal we will simulate several situations to show the performance of our synchronization algorithm.

关键词：传感器；时间同步

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Wireless sensor networks (WSNs) have generated immense interest among researches for the last few years motivated by several theoretical and practical challenges. The increase in interest is mainly attributed to new applications designed with large scale networks consisting of devices capable of performing computations on the sensed data and finally processing the data for transmitting to remote locations. Providing security to WSNs plays a major role as these networks are generally deployed in inaccessible terrain and also for their communication being in the wireless domain. These reasons impose security mechanisms to be employed on the highly vulnerable sensor networks that are robust enough to handle attacks from adversaries. WSNs consist of nodes having limited resources and therefore classical security measures applicable in traditional networks cannot be applied here. So the need of the hour is using systems that lie within the boundary of the sensor nodes resource potential as well competent enough to handle attacks. Intrusion detection is one such defense used in sensor networks having the ability to detect unknown attacks and finding means to thwart them. Researches have found intrusion detection system (IDS) to be very much compatible in sensor networks. Therefore intrusion detection holds a very prominent research area for researchers. So familiarity with this promising research field will surely benefit the researchers. Keeping this in mind we survey the major topics of intrusion detection in WSNs. The survey work presents topics such as the architectural models used in the different approaches for intrusion detection, different intrusion detection techniques and highlights intrusion detection methods applicable for the different layers in sensor networks. The earlier achievements in intrusion detection in WSNs are also summarized along with more recent works and existing problems are discussed. We also give an insight into the possible directions for future work in intrusion detection involving different aspects in sensor networks.

关键词：无线传感器；问题；挑战；方法

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