1566772
A General Resource Management Framework for Real-Time Operating Systems
In RED-Linux kernel, a General Scheduling Framework (GSF) has been implemented. Under GSF, different scheduling algorithms can be easily implemented. However GSF only addresses the scheduling of CPU. Other system resources are not considered. In this paper we propose a general resource management framework for various OS resources. When user applications request and consume system resources, they may use uniform APIs although each type of OS resource has its own properties and means to be controlled. In the resource management framework, we also allow the inter-relationship between different types of resources to be defined and managed.
15072976
The design and implementation of real-time schedulers in RED-linux
Researchers in the real-time system community have designed and studied many advanced scheduling algorithms. However, most of these algorithms have not been implemented since it is very difficult to support new scheduling algorithms on most operating systems. To address this problem, we enhance the scheduling mechanism in Linux to provide a flexible scheduling framework. In the real-time and embedded Linux (RED-Linux) project, we implement a general scheduling framework which divides the system scheduler into two components: dispatcher and allocator. The dispatcher provides the mechanism of system scheduling and resides in the kernel space. The allocator is used to define the scheduling policy and implemented as a user space function. This framework allows users to implement application-specific schedulers in the user space which is easy to program and to debug. The framework also relieves the deficiency from the stock Linux scheduler which is not designed for real-time applications. To further enhance its power, a hierarchical scheduling mechanism has been provided in RED-Linux to allow a system designer to integrate different real-time applications together. Using scheduling groups, real-time jobs can be managed and scheduled in a hierarchical manner. In this paper, we discuss how the group mechanism is implemented in RED-Linux.
5475349
Scheduling Real-Time Systems with End-to-End Timing Constraints Using the Distributed Pinwheel Model
Real-time distributed applications have timing constraints on tasks running on several processors. To design real-time systems with end-to-end performance requirements, we need to have algorithms to schedule and to coordinate tasks on different processor nodes. An end-to-end scheduling approach based on the pinwheel scheduling model is presented for distributed real-time systems, We show how tasks on different nodes may be transformed to have periods consisting of only harmonic numbers. With harmonic periods, we can use a polynomial-time algorithm to find the start and finish times of each task on each node. Phase alignment algorithms are then applied to adjust the phases between schedules of neighboring nodes so that the overall end-to-end delay is minimized. Using the distributed pinwheel model, schedules on different nodes are synchronized to lessen the delays. For many real-time systems, this approach provides a predictable performance and a short end-to-end delay.
22001959
A Pinwheel Scheduler for Three Distinct Numbers with a Tight Schedulability Bound
Abstract. Given a multiset of positive integers 
 $A=\{a_1,a_2,\ldots,a_n\}$ , the pinwheel problem is to find an infinite sequence over 
 $\{1,2,\ldots,n\}$ such that there is at least one symbol i within any subsequence of length ai. The density of A is defined as 
 $\rho(A)=\sum^n_{i=1} (1/a_i)$ . In this paper we limit ourselves to instances composed of three distinct integers. The best scheduler [5] published previously can schedule all instances with a density of less than 0.77. A new and fast scheduling scheme based on spectrum partitioning is presented in this paper which improves the 0.77 result to a new 
 $\frac{5}{6}\approx 0.83$ density threshold. This scheduler has achieved the tight schedulability bound of this problem.
27737931
Designing multimedia applications on real-time systems with SMP architecture
Large real-time multimedia systems such as flight simulators have adopted multiprocessor architecture to handle the large amount of events and computations. Existing realtime scheduling algorithms designed for single-processor systems such as Rate Monotonic (RM) and Earliest Deadline First Algorithm (EDF) have very poor performance on multiprocessor systems. On the other hand, most online scheduling algorithms for multiprocessor systems have poor schedulability conditions for real-time applications. In this paper, we study different ways to design real-time applications on SMP machines.
13997680
Distributed real-time system design using CBS-based end-to-end scheduling
Distributed real-time applications share a group of processors connected by some local area network. A rigorous and sound methodology to design real-time systems from independently designed distributed real-time applications is needed. In this paper, we study a distributed real-time system design scheme using CBS-based end-to-end scheduling. The scheduling scheme utilizes CBS to allocate both CPU shares and network bandwidth to a distributed real-time application when it arrives at the system. Our proposed solution uses the same scheduling paradigm for both resources. In this way, we believe the system can have a more consistent scheduling objective and may achieve a tighter schedulability condition.
12237012
Discovering the Biomedical Deep Web
The rapid growth of biomedical information in the Deep Web has produced unprecedented challenges for traditional search engines. This paper describes a new Deep web resource discovery system for biomedical information. We designed two hypertext mining applications: a Focused Crawler that selectively seeks out relevant pages using a classifier that evaluates the relevance of the document with respect to biomedical information, and a Query Interface Extractor that extracts information from the page to detect the presence of a Deep Web database. Our anecdotes suggest that combining focused crawling with query interface extraction is very effective for building high-quality collections of Deep Web resources on biomedical topics.
46019766
A Study on Textual Entailment
In this paper we study a graph-based approach to the task of textual entailment between a text and hypothesis. The approach takes into account the full lexico-syntactic context of both the text and hypothesis and relies heavily on the concept of subsumption. It starts with mapping the text and hypothesis into graph structures where nodes represent concepts and edges represent lexico-syntactic relations among concepts. Based on a subsumption score between the text-graph and hypothesis-graph an entailment decision is then made. The impact of synonymy on entailment is quantified and discussed. An important advantage of our solution is the ability to customize it so that high-confidence results are obtained
1161117
Fast Similarity Search in the Presence of Noise, Scaling, and Translation in Time-Series Databases
We introduce a new model of similarity of time sequences that captures the intuitive notion that two sequences should be considered similar if they have enough non-overlapping time-ordered pairs of subsequences thar are similar. The model allows the amplitude of one of the two sequences to be scaled by any suitable amount and its offset adjusted appropriately. Two subsequences are considered similar if one can be enclosed within an envelope of a specified width drawn around the other. The model also allows non-matching gaps in the matching subsequences. The matching subsequences need not be aligned along the time axis. Given this model of similarity, we present fast search techniques for discovering all similar sequences in a set of sequences. These techniques can also be used to find all (sub)sequences similar to a given sequence. We applied this matching system to the U.S. mutual funds data and discovered interesting matches.
362708
Low-Cost RFID Identification Variation
Interests continue to grow in recent years for the adoption of Radio Frequency Identification (RFID) in many different areas including transportation and supply chain management. Those RFID-included objects can be targeted more efficiently by real-time tracking and instant management. However, because of the contact-less type of RFID remote retrieval, the transmission of data in the air is very vulnerable to eavesdropping or appropriation. A primary security concern surrounding RFID technology is the illicit tracking of consumer location and analyzing of their shopping habits or behavior. This paper proposes a more secure and lightweight RFID variation protection protocol which enhances the security of the transmission of information as well as the consumer privacy protection by using randomized control access and two-way identification. In addition, this protocol also improves the overall performance and lowers the cost of RFID tag without any complicated calculation.
13951248
A survey on evaluating and realizing IS/IT benefits in Taiwanese b2bec companies
A number of issues have emerged from the analysis of the data collected via a survey conducted in Taiwanese B2BEC companies. The results show relatively high usage of IS/IT investment evaluation and benefits realization methodologies, and yet, these methodologies were generally not used effectively within the responding organizations. Most of these organizations were not yet mature in terms of their IT. However, there was a clear association between level of IT maturity and both wide and effective use of methodologies for IS/IT investment evaluation and benefits management.