15404238
Process resurrection: a fast recovery mechanism for real-time embedded systems
This paper describes a fast recovery mechanism that meets the requirements of embedded real-time systems. In general purpose computing, restart is an established technology for achieving high availability. Restart has also been used in soft real-time systems where the temporary interruption of service is undesirable but acceptable. However, it has not been widely used in small embedded real-time systems with hard deadlines, mainly because the traditional approaches do not meet their requirements of low memory and processor overhead, and fast response times with little variations. We have developed process resurrection, a novel restart mechanism for recovering from crash failures to meet these requirements. The experiments on an inverted pendulum control system shows that it can recover the control process in time after a crash (eg. segmentation fault). Another experiment conducted on an MP3 audio player shows that this technique is also applicable to some multimedia applications.
17067182
A dependable online testing and upgrade architecture for real-time embedded systems
When real-time embedded system software needs to be upgraded, it will be more dependable if the new software is sufficiently tested on the actual deployment platform. The challenge is to provide a safeguard for protecting the normal operations from faulty upgrades. However, the safeguard must be not only efficient but also able to be added and taken away as needed without shutting down the normal operations. We have developed an architecture based on simplex architecture and process resurrection and have applied it to the inverted pendulum control system. The measurements show that the overhead is small and justifiable.
11611370
A component model for building systems software
OpenCOM v2 is our experimental language-independent component-based systems-building technology. OpenCOM offers more than merely a component-based programming model. First, it is a runtime component model and supports dynamic runtime reconfiguration of systems (i.e. one can load, unload, bind, and rebind components at runtime). Second, it explicitly supports the deployment of the model in a wide range of ‘deployment environments’ (e.g. operating systems, PDAs, embedded devices, network processors). Third, it allows the particularities of different deployment environments to be selectively hidden from/ made visible to the OpenCOM programmer without inherent performance overhead.
34164098
A New EM Algorithm for Resource Allocation Network
Clustering usually assumes that the number of clusters is known or given. No knowledge of such a priori information is needed to find an appropriate number of clusters. This paper introduces an elliptical clustering algorithm with incremental growth of clusters, which is derived from the batch EM algorithm with a decay factor and a novelty criterion. The proposed algorithm can start with no or a small number of clusters. Whenever unusual data is presented, the algorithm adds a new cluster and finally the number of clusters in the data is obtained after clustering. The usefulness of the proposed algorithm is demonstrated for texture image segmentation and skin image segmentation.
6972987
Scalable service differentiation in a shared storage cache
Motivated by the need to enable easier data sharing and curb rising storage management costs, storage systems are becoming increasingly consolidated and thereby shared by a large number of users and applications. In such environments, service differentiation becomes increasingly important. Since caching is a fundamental and pervasive technique employed to improve the performance of storage systems, providing differentiated services from a storage cache is a crucial component of the entire end-to-end QoS solution. In this paper we discuss a QoS architecture for a shared storage proxy cache which can provide long-term hit rate assurances to competing classes. The proposed architecture consists of three components: (a) per-class feedback controllers that track the performance of each class, (b) a fairness controller that allocates excess resources fairly in the case when all goals are met, and (c) a contention resolver that decides cache allocation in the case when at least one class does not meet its target hit rate. We compare the performance of various feedback per-class controllers, and provide guidelines for designing QoS mechanisms for such a dynamic environment.
24310355
Component-Based Online Learning for Face Detection and Verification
Component detectors can accurately locate facial components, and component-based approaches can be used to build detectors that can handle partial occlusions. This paper proposes a face detection and verification method using component-based online learning. The main difference from previously reported component-based approaches is the use of online learning, which is ideal for highly repetitive tasks. This results in faster and more accurate face detection, because system performance improves with continued use. Further, uncertainty is added by calculating the standard deviation of face components and their relations.
16838706
Hangul, the Korean Writing System, and its Computational Treatment
In this paper I will describe how the efficiency of the Hangul writing system can be transferred to its coding on computers. I will also review the encodings of Hangul by the precomposed Hangul code set of KSC 5601, a combinational Hangul code set, and ISO 2022, and their applications to the development of Hangul pro grams for sorting, editing, and processing Korean text. I then conclude with remarks on the merger efforts of the Unicode standard and ISO DIS 10646 on Hangul.