13132411
A New Probabilistic Induction Method
Knowledge acquisition by interviewing a domain expert is one of the most problematic aspects of the development of expert systems. As an alternative, methods for inducing concept descriptions from examples have proven useful in eliminating this bottleneck. In this paper, we propose a probabilistic induction method (PIM), which is an improvement of the Chan and Wong method, for detecting relevant patterns implicit in a given data set. PIM uses the technique of residual analysis and several heuristics to effectively detect complex relevant patterns and to avoid the problem of combinatorial explosion. A reasonable trade-off between the induction time and the classification ratio is achieved. Moreover, PIM quickly classifies unknown objects using classification rules converted from the positively relevant patterns detected. Three experiments are conducted to confirm the validity of PIM.
46555623
Design and evaluation of fault-tolerant interleaved memory systems
A highly reliable interleaved memory system for uniprocessor and multiprocessor computer architectures is presented. The memory system is divided into groups. Each group consists of several banks and furthermore, each bank has several memory units. Spare memory units as well as spare banks are incorporated in the system to enhance reliability. Reliability figures are derived to evaluate systems with various amounts of redundancy. The result shows that the system reliability can be significantly improved with little hardware overhead. User transparency in memory access is retained.<<ETX>>
8966167
Reliability evaluation of multi-state systems subject to imperfect coverage using OBDD
This paper presents an efficient approach based on OBDD for the reliability analysis of a multi-state system subject to imperfect fault-coverage with combinatorial performance requirements. Since there exist dependencies between combinatorial performance requirements, we apply the multi-state dependency operation (MDO) of OBDD to deal with these dependencies in a multi-state system. In addition, this OBDD-based approach is combined with the conditional probability methods to find solutions for the multi-state imperfect coverage models. Using conditional probabilities, we can also apply this method for modular structures. The main advantage of this algorithm is that it will take computational time that is equivalent to the same problem without assuming imperfect coverage (i.e. with perfect coverage). This algorithm is very important for complex systems such as fault-tolerant computer systems, since it can obtain the complete results quickly and accurately even when there exist a number of dependencies such as shared loads (reconfiguration), degradation and common-cause failures.
26449771
Resolving error propagation in distributed systems
This paper investigates the problem of error propagation in distributed systems. To resolve this problem, a state preservation scheme is presented to save process states in main memory. Based on the state preservation, the processes suffering from error propagation can be recovered without involving stable storage. The recovery overhead is significantly reduced. In addition, a well-known single-source-all-destination graph algorithm is also utilized to find the optimal recovery points of the processes suffering from error propagation.
11124619
Effort-index-based software reliability growth models and performance assessment
The authors show that the logistic testing effort function is practically acceptable/helpful for modeling the software reliability growth and providing a reasonable description of resource consumption. Therefore, in addition to the exponential shaped models, we integrate the logistic testing effort function into an S-shaped model for further analysis. The model is designated as the Yamada Delayed S-shaped model. A realistic failure data set is used in the experiments to demonstrate the estimation procedures and results. Furthermore, the analysis of the proposed model under an imperfect debugging environment is investigated. In fact, from these experimental results and discussions, it is apparent that the logistic testing-effort function is very suitable for making estimations of resource consumption during the software development/testing phase.
6454250
An Efficient Time-Based Checkpointing Protocol for Mobile Computing Systems over Mobile IP
Time-based coordinated checkpointing protocols are well suited for mobile computing systems because no explicit coordination message is needed while the advantages of coordinated checkpointing are kept. However, without coordination, every process has to take a checkpoint during a checkpointing process. In this paper, an efficient time-based coordinated checkpointing protocol for mobile computing systems over Mobile IP is proposed. The protocol reduces the number of checkpoints per checkpointing process to nearly minimum, so that fewer checkpoints need to be transmitted through the costly wireless link. Our protocol also performs very well in the aspects of minimizing the number and size of messages transmitted in the wireless network. In addition, the protocol is nonblocking because inconsistencies can be avoided by the piggybacked information in every message. Therefore, the protocol brings very little overhead to a mobile host with limited resource. Additionally, by taking advantage of reliable timers in mobile support stations, the time-based checkpointing protocol can adapt to wide area networks.
40096305
Quantitative software reliability modeling from testing to operation
We first describe how several existing software reliability growth models based on nonhomogeneous Poisson processes (NHPPs) can be derived based on a unified theory for NHPP models. Under this general framework, we can verify existing NHPP models and derive new NHPP models. The approach covers a number of known models under different conditions. Based on these approaches, we show a method of estimating and computing software reliability growth during the operational phase. We can use this method to describe the transitions from the testing phase to operational phase. That is, we propose a method of predicting the fault detection rate to reflect changes in the user's operational environments. The proposed method offers a quantitative analysis on software failure behavior in field operation and provides useful feedback information to the development process.