1170919
A Hybrid Method for Constructing Semi-structural Process in Knowledge-Intensive Information System
Recent research on processes in information system has revealed that processes in prevalent fields present to be semi-Structural. It seems to be structural at the process layer, but in the enacting time, executive situation might change due to various reasons. To solve that, in this paper, we illustrate how the flexibility of construction processes can be handled using a hybrid method. At structural layer, we construct the process in imperative way, whereas at the lower level, we decompose tasks into fine-grained operations, and declaratively perceive operation sequence. Moreover, we propose a prototype tool for constructing and enacting semi-Structural business processes.
2862393
Online Constrained Pattern Detection over Streams
Online pattern detection poses a challenge in many data-intensive applications, including network traffic management, trend analysis, intrusion detection, and various intelligent sensor networks. These applications have to be time and space efficient while providing high quality answers. Meanwhile, far less attention has been paid for detecting constrained patterns, that cannot be simply matched because there is no available pattern for prediction. This paper presents our research effort in efficient pattern detection with constraint. We propose a new method named Online Pattern Detection with Constraint (OPDC) to detect constrained patterns over evolving data stream, taking into account various user-defined constraints. To ensure that the constrained patterns are representative, we extend regular expression in a simple but powerful way. Our experimental results on real data sets demonstrate the feasibility and effectiveness of the proposed scheme.
6828357
Study on Traffic Information Fusion Algorithm Based on Support Vector Machines
Support vector machine (SVM) is a new sort of machine learning method based on structure risk minimization (SRM) principle, which has high generalization capability. Many problems with small samples, nonlinearity or high dimension in pattern recognition could be solved by the method. In this paper, the traffic data on freeway were taken as research objects and an information fusion algorithm based on SVM about freeway incident detection was proposed. A SVM was trained and tested using the data obtained from the simulation under the condition of incident and non-incident. Compared with the multi-layer feed forward neural network (MLF) algorithm trained with the same data, the simulation results showed that the SVM offers a lower misclassification rate, higher correct detection rate and lower false alarm, and it can improve the detection performance
16447326
An Approximate Method for Performance Evaluation of Asynchronous Pipeline Rings
Performance evaluation of asynchronous circuits is one of the most difficult parts in asynchronous circuit research. This Paper presents an approximate method by queuing network modeling for performance evaluation of asynchronous pipeline rings. The asynchronous pipeline rings are modeled by closed queuing networks with transfer blocking. An efficient approximation method is used to analyze the performance metrics, such as response time and throughput. These performance metrics can be used to derive the cycle time and latency of the asynchronous pipeline rings. Compared with theoretic results, the algorithm presented in this paper is efficient for performance evaluation of asynchronous pipeline rings.
29608911
Password Recovery on Challenge and Response: Impossible Differential Attack on Hash Function
We propose practical password recovery attacks against two challenge-response authentication protocols using MD4. When a response is computed as MD4(Password||Challenge), passwords up to 12 characters are practically recovered. To recover up to 8 characters, we need 16 times the amount of eavesdropping and 16 times the number of queries, and the off-line complexity is less than 235 MD4 computations. To recover up to 12 characters, we need 210 times the amount of eavesdropping and 210 times the number of queries, and the off-line complexity is less than 240 MD4 computations.When a response is computed as MD4(Password||Challenge||Password), passwords up to 8 characters are practically recovered by 28 times the amount of eavesdropping and 28 times the number of queries, and the off-line complexity is less than 239 MD4 computations. Our approach is similar to the "Impossible differential attack", which was originally proposed for recovering the block cipher key. Good impossible differentials for hash functions are achieved by using local collision. This indicates that the presence of one practical local collision can damage the security of protocols.
14259461
Grid Unit: A Self-Managing Building Block for Grid System
Grid system software is inherently complex, hard to build and maintain. In this paper, we propose a self-managing building block: grid unit, which facilitates constructing grid system with higher availability and lower management overhead. We present an agent organization as autonomic management framework, and propose a self-recovering protocol to eliminate most of tough jobs from system administrator's routines. The system has been deployed on Dawning 4000A since 2004, the biggest node for China grid system. We have done extensive experiments to evaluate grid unit, and the collected log data shows the availability of a grid parallel process management service, built on the basis of grid unit, reaches 99.997%.
15162154
Trust Mechanism in Distributed Access Control Model of P2P Networks
Peer-to-peer network technologies have gained popularity without the need for centralized servers. With the consistent development of the network, the existing techniques about access control could not resolve the security issues in P2P networks perfectly. How to realize the trust mechanism in access control system is an important subject of P2P security research. In this paper, we analyze the lack of trust mechanism in the existing access control models, and present a recommendation trust model based on reputation. We introduce the related concepts in the trust model and explain the mechanism of trust. Then, a protocol of trust query is designed and calculations about trust are given. At last, we validate the availability of the trust model, and applied it in the existing access control model. The combining of trust mechanism and access control technologies makes the P2P networks securer.