Efficient Algorithms for Test Sequence Selection (Extended Abstract)

Abstract:We study the test sequence selection problem. Given a large number of tests for a protocol system, we want to select a subset of tests so that the number of tests is reduced yet the test coverage is not sacrificed. We discuss the complexity of the test selection problem and propose a class of algorithms for different protocol system information requirements, test coverage criteria, and cost. This article is an extended abstract of [LH], and we refer the interested readers to the full paper for a detailed study and experimental results. 1

An Alternative Model for Scheduling on a Computational Grid

In this paper we discuss scheduling on a computational grid of autonomous nodes. A two level process involves a meta-scheduler whose objective is to generate an optimal schedule and reduce the total execution time of an work-flow, and local schedulers whose objective is to optimize the utilization of local resources. We introduce several resource allocation and consumption models and discuss issues pertinent to decision making with incomplete and/or outdated information. Then we present a stock market model for scheduling on a computer grid with autonomous nodes. 1 Introduction A computational grid is a large-scale, heterogeneous collection of autonomous systems, geographically distributed and interconnected by low latency and high bandwidth networks. The mission of a grid is to provide dependable services at a low cost for a large community of users and to support collaborative work. The term "computational grid" is based on the analogy with the "power grid", it reflects the desire t..

Bond System Monitor

Bond is a message-oriented middleware for network computing on a grid of autonomous nodes. It consists of a distributed object communication fabric, servers, and agents. Core servers are permanent objects providing services such as directory service, dispatching, authentication, monitoring, and others. The Bond system monitor is responsible for starting up core servers, keeping them running, and balancing the load among them. In this paper, we discuss the remote server start-up and the executables failure detection functions of the monitor and present the backup monitor. Contents: 1. Abbreviations and terms 2. Introduction 3. System monitor Remote server start-up Failure detection Backup monitor 4. Future work 5. Conclusions 1. Abbreviations and terms Backup system monitor: core server; it takes control of the system when the primary system monitor fails. Shadow of a Bond object: abstraction supporting communication with a remote object. A shadow is a local object acting as a prox..

DDOS SCOUTER: A SIMPLE IP TRACEBACK SCHEME

Abstract Defense against distributed denial-of-service attacks is one of the hardest security problems on the Internet. Among those problems, the most difficult problem is to trace the attacks back to its origin for the attackers always use incorrect or spoofed IP addresses in the attack packets. In this paper, we propose a multi-edge marking scheme, which allow the victim to traceback to or near to the origin of the attackers with the help of the network administrator. The scheme features high performance efficiency and no false positive. Compared with the previous solutions, it has high precision and low computation overhead for victim to reconstruct the attack paths. Base on this marking scheme, DDoS Scouter is developed

Bootstrap tests for structural change with infinite variance observations

The quest of structural change with infinite variance observations appears to be relatively common. Conventional residual CUSUM of squares test (RCUSQ) are unreliable in the presence of such behavior, having nonpivotal asymptotic null distributions. In this paper we propose a residual-based bootstrap approach to RCUSQ testing that is valid against a range of infinite variance processes. Our proposed method does not require the practitioners to specify knowledge for tailed index. Consistency and the rate of convergence for the estimated change point are also obtained. We also show via simulations that our asymptotic results provide good approximations in finite samples. In addition, we apply our results to investigate the original returns for NO.1 SDS using a historical data set that covers the period 1999-2002.