Run-time malware detection based on positive selection

This paper presents a supervised methodology that detects malware based on positive selection. Malware detection is a challenging problem due to the rapid growth of the number of malware and increasing complexity. Run-time monitoring of program execution behavior is widely used to discriminate between benign and malicious executables due to its effectiveness and robustness. This paper proposes a novel classification algorithm based on the idea of positive selection, which is one of the important algorithms in Artificial Immune Systems (AIS), inspired by positive selection of T-cells. The proposed algorithm is applied to learn and classify program behavior based on I/O Request Packets (IRP). In our experiments, the proposed algorithm outperforms ANSC, Na? ve Bayes, Bayesian Networks, Support Vector Machine, and C4.5 Decision Tree. This algorithm can also be used in general purpose classification problems not just two-class but multi-class problems.     

网格环境下基于分块的任务执行时间的预测算法

针对当前已有预测算法不实时、对负载变化不敏感的问题,结合网格中任务的特点提出新的基于分块的预测算法。该方法从子节点任务执行出发,提出把执行的任务分成两个部分,用前一部分的执行情况来预测剩下部分的执行时间。实验证明,该算法比已有预测算法有更高的效率和通用性。     

Performance of a Time Warp based simulator of large scale PCS networks

This paper describes an object-oriented Time Warp (TW) mechanism which supports general parallel simulation on a distributed, possibly heterogeneous, computing environment. As a significant application of the developed TW, a simulation model adequate for large personal communication services (PCS) networks is proposed and its performance results given. Special attention is paid to such TW critical issues as load balancing and checkpointing interval tuning which strongly affect the achievement of good speedups. The experimental results confirm that good performance can be obtained on an heterogeneous distributed system provided an accurate parameter tuning is accomplished.     

Similarity-margin based feature selection for symbolic interval data

In this paper we propose a feature selection method for symbolic interval data based on similarity margin. In this method, classes are parameterized by an interval prototype based on an appropriate learning process. A similarity measure is defined in order to estimate the similarity between the interval feature value and each class prototype. Then, a similarity margin concept has been introduced. The heuristic search is avoided by optimizing an objective function to evaluate the importance (weight) of each interval feature in a similarity margin framework. The experimental results show that the proposed method selects meaningful features for interval data. In particular, the method we propose yields a significant improvement on classification task of three real-world datasets.     

基于时间不确定性的HLA乐观时间同步

在现有仿真时间推进机制中，事件的发生时间采用精确的时间戳，但是有时事件的发生时间用一个时间区间来表达更合理。该文提供了一种新的时间卷曲方法来发掘事件发生时间的不确定性，此方法的核心思想是：用事件的时间区间模型代替精确时间戳模型来提高事件并发性；当事件的时间区间重叠时用因果关系防止失序；对因果关系事件采用语义学方法进行区分，防止过多回滚。在RTI上增加时间管理扩展组件，用来实现基于时间区间的乐观时间同步机制。     

设备工程监理中进度控制的偏差分析法研究

为了使设备工程监理中的进度控制方法更加完全,提出了偏差分析法。它包括曲线比较法与投资偏差分析法两种进度控制方法,其中曲线比较法分为S形曲线比较法、香蕉曲线比较法和前锋线比较法。利用这两种进度控制方法,均能直接判断进度状况,并计算出相应的进度偏差值。在某污水处理站的实际应用表明,该方法在进度控制方面取得了很好的效果,完善了设备工程监理的进度控制方法体系。     

On process migration and load balancing in Time Warp

A load balancing algorithm for a discrete event simulation executed under Time Warp is presented. The algorithm rests upon recent developments in active process migration, which permit the use of dynamic strategies. Dynamic load balancing allows for readjustments when resource requirements vary during simulation. It is also useful when initial resource predictions are unknown or incorrect. A simulated multiprocessor environment (PARALLEX) was developed in order to evaluate the algorithm. The results indicate that substantial performance gains may be realized with the algorithm     

Performance analysis of Time Warp with multiple homogeneousprocessors

The behavior of n interacting processors synchronized by the Time Warp protocol is analyzed using a discrete-state, continuous-time Markov chain model. The performance and dynamics of the processes (or processors) are analyzed under the following assumptions: exponential task times and timestamp increments on messages, each event message generates one new message that is sent to a randomly selected process, negligible rollback, state saving, and communication delay, unbounded message buffers, and homogeneous processors. Several performance measures are determined, such as: the fraction of processed events that commit, speedup, rollback probability, expected length of rollback, the probability mass function for the number of uncommitted processed events, the probability distribution function for the virtual time of a process, and the fraction of time the processors remain idle. The analysis is approximate, thus the results have been validated through performance measurements of a Time Warp testbed executing on a shared-memory multiprocessor     

The Effect of Memory Capacity on Time Warp Performance

The behavior of n interacting processes synchronized by the "Time Warp" rollback mechanism is analyzed under the constraint that the total amount of memory to execute the program is limited. In Time Warp, a protocol called "cancelback" has been proposed to reclaim storage when the system runs out of memory. A discrete state, continuous time Markov chain model for Time Warp augmented with the cancelback protocol is developed for a shared memory system with n homogeneous processors and homogeneous workload with constant message population. The model allows one to predict speedup as the amount of available memory is varied. The performance predicted by the model is validated through performance measurements on an operational Time Warp system executing on a shared-memory multiprocessor using a workload similar to that in the model. It is observed that if the sequential simulation requires m message buffers, Time Warp with a small fraction of message buffers beyond m performs almost as well as Time Warp with unlimited memory.     

基于后向区间选择偏最小二乘算法的软测量建模

偏最小二乘是在光谱多变量校正中广泛使用的一种算法,现已经发现高效的变量选择不仅能够提高模型的预测能力,也可大大降低模型的复杂度。为了建立具有鲁棒性和低复杂度的基于光谱的在线软测量模型,考虑到光谱变量之间高度相关这一事实,提出一种基于后向区间选择策略的偏最小二乘算法。该算法主要步骤是:先将光谱波长域细分为一定数量的等长子区间;再采用后向淘汰的策略,将各个子区间逐步淘汰,形成一个淘汰序列;最后,再反向选择一定数量的子区间建立最终的模型。通过一个实例以及与传统基于全谱的偏最小二乘算法比较,显示出了该算法的在建立软测量模型方面的优良性能。     

An investigation of the use of world views with shared variables in Time Warp

We investigate how four world views currently in use for sequential simulation can be used with shared variables in parallel discrete event simulation with Time Warp. The worlds view include event, activity, three phase, and process interaction. The mechanism to share variables uses the full-replication strategy. Some programming and performance analysis results of the various implementations are also presented.     

Efficient execution of Time Warp programs on heterogeneous, NOWplatforms

Time Warp is an optimistic protocol for synchronizing parallel discrete event simulations. To achieve performance in a multiuser network of workstation (NOW) environment, Time Warp must continue to operate efficiently in the presence of external workloads caused by other users, processor heterogeneity, and irregular internal workloads caused by the simulation model. However, these performance problems can cause a Time Warp program to become grossly unbalanced, resulting in slower execution. The key observation asserted in this article is that each of these performance problems, while different in source, has a similar manifestation. For a Time Warp program to be balanced, the amount of wall clock time necessary to advance an LP one unit of simulation time should be about the same for all LPs. Using this observation, we devise a single algorithm that mitigates these performance problems and enables the “background” execution of Time Warp programs on heterogeneous distributed computing platforms in the presence of external as well as irregular internal workloads     

基于时间电压转换方式的新型户用超声热量表设计

基于超声波流量测量原理,采用高性能MSP430和高精度时间电压转换方式设计了微功耗且具有M-BUS通信功能的热量表,并对其硬件结构及主程序进行研究。     

Run-time optimization of heterogeneous media access in a multimediaserver

Discrete media (DM) data throughput is vital to systems that need to support the heterogeneity and variety of data found in interactive hypermedia and digital library applications. Therefore, a multimedia server's ability in delivering a high DM data throughput without degrading its CM data throughput deserves more attention. In this paper, we address this issue by optimizing the use of disk bandwidth spent on CM service at run-time and redirecting the saved bandwidth to service DM requests. Based on a new cost model of disk access incurred in CM service, we formulate strategies to control the size of each disk read at run time. These strategies improve the efficiency of each disk access and improve the DM data throughput of a multimedia server, without jeopardizing the CM throughput. Through experimental evaluations, the improvements achieved are demonstrated. Furthermore, efficient control of the allocation of disk bandwidth between DM and CM services over a wide range is also demonstrated     

Molecular dynamics simulations for selection of kinetic hydrate inhibitors

Natural gas hydrates are ice-like structures composed of water and gas molecules that have long been a problem in petroleum industry. Heavy cost of alcohol and glycol injection has spurred an interest in called ‘kinetic inhibitors’ able to slow down the hydrate formation rather than prevent it. Since it is not possible to compare directly the macroscopic effects of different inhibitors on the kinetics of hydrate formation in computer experiments, a scheme capable of culling the list of candidates for experimental testing was proposed earlier [B. Kvamme, G. Huseby, O.K. Førrisdahl, Molecular dynamics simulations of PVP kinetic inhibitor in liquid water and hydrate/liquid water systems, Mol. Phys. 90 (1997) 979–991]. Molecular dynamics simulations were implemented to test several kinetic inhibitors in a multiphase water–hydrate system with rigid hydrate interface. In addition, a long-scale run was implemented for a system where the hydrate was free to melt and reform. Our conclusion that PVCap will outperform PVP as a kinetic hydrate inhibitor is supported by experimental data. We demonstrate that numerical experiments can be a valuable tool for selecting kinetic inhibitors as well as provide insight into mechanisms of kinetic inhibition and hydrate melting and reformation.     

Necessary and sufficient checkpoint selection for temporal verification of high-confidence cloud workflow systems

On-time completion is an important temporal Qo S(Quality of Service) dimension and one of the fundamental requirements for high-confidence workflow systems. In recent years, a workflow temporal verification framework, which generally consists of temporal constraint setting, temporal checkpoint selection, temporal verification, and temporal violation handling, has been the major approach for the high temporal Qo S assurance of workflow systems. Among them, effective temporal checkpoint selection, which aims to timely detect intermediate temporal violations along workflow execution plays a critical role. Therefore, temporal checkpoint selection has been a major topic and has attracted significant efforts. In this paper, we will present an overview of workflow temporal checkpoint selection for temporal verification. Specifically, we will first introduce the throughput based and response-time based temporal consistency models for business and scientific cloud workflow systems,respectively. Then the corresponding benchmarking checkpoint selection strategies that satisfy the property of“necessity and sufficiency” are presented. We also provide experimental results to demonstrate the effectiveness of our checkpoint selection strategies, and finally points out some possible future issues in this research area.     

开放网络环境下软件运行时故障诊断研究

在开放网络环境中,软件运行时的故障诊断与查找是必要的.利用软件运行时的外在表现特征与所有可能的故障建立隐马尔可夫模型,在应用中收集软件运行时外在表现特征的数据,可以诊断出用普通方法不易诊断出的软件故障.在建立隐马尔可夫模型过程中,文中提出使用"3σ原则"来离散化连续型随机变量,其在变量离散化及确定参数先验值方面具有独特优势,操作既方便又符合实际情况,且具有严格的理论依据;同时,给出一个开放网络环境的应用案例.通过仿真实验,证实本文所提出的方法在软件运行时故障诊断方面较其他方法具有独特的优势.     

Application of fuzzy measures and interval computation to financial portfolio selection

As many data‐driven fields, finance is rich in problems requiring high computational power and intelligent systems techniques. In particular, the problem of selecting an optimal financial portfolio can be conveniently represented as a constrained optimization problem or a decision‐making problem. The aim of this paper is to show how to express the optimal portfolio selection problem from a decision‐theoretic perspective and show how to address this problem using fuzzy measures and fuzzy integrals. © 2010 Wiley Periodicals, Inc.     

Use of multi-objective genetic rule selection for examining the effectiveness of inter-vehicle communication in traffic simulations

Recently, inter-vehicle communication (IVC) has been actively studied to attempt to avoid traffic congestion. In this article, we propose the idea of using fuzzy rules to examine the effectiveness of IVC. In the proposed approach, we first collect travel records (e.g., travel time, travel path, traffic volume) of vehicles with IVC from our cellular automata-based traffic simulator. Various kinds of available information for vehicles with IVC are used in the antecedent part of our fuzzy rules. The level of effectiveness of IVC is discretized into four categories (i.e., four classes) in this article. The consequent class of each fuzzy rule is one of those four classes. Next we generate a large number of fuzzy rules from the collected data. Then we select only a small number of fuzzy rules by multi-objective genetic rule selection. We use three objectives: to maximize the accuracy, to minimize the number of selected rules, and to minimize the total rule length (i.e., the total number of antecedent conditions). Our approach can find a number of nondominated fuzzy-rule-based systems with respect to their accuracy and complexity. Finally, we analyze the effectiveness of IVC using fuzzy rules in the fuzzy-rule-based systems obtained through their linguistic interpretation.