15828117
Enhancing external consistency in real-time transactions
Real-time computing brings two new requirements to database management. The first is the deadline constraint which requires better scheduling algorithms to meet transaction deadfines. The second requirement is the temporal validity, or external consistency[Lin89], requirement of data: a real-time database must prevent data from being corrupted not only by the executions of concurrent transactions but also by the delay from sharing computing resources and real-time scheduler decisions. In this paper, we study the external consistency requirement in real-time databases. We propose a semantic-based concurrency control scheme that prefers the external consistency to the traditional serializability. Two new concepts are introduced in our work. An update of a physical object value is considered to be compatible to those read operations that need to access the most recent data. Secondly, if a transaction depends strongly on the validity of the value of an object, a new update may cause the transaction to be aborted since continuing the transaction may be harmful to the appfication. A real-Life example is the stock market database. A trading program may be executed for a long time and its read operations should not block any new updates. Moreover, if there is a big sudden change in a particular stock price, it may be better to abort an on-going transaction rather than letting it make some invalid decisions.
44711812
An open real-time environment for parallel and distributed systems
Most computer-based systems have hard real-time constraints. Schedulers in complex systems must be designed to manage a set of applications developed and deployed independently. We study an open real-time environment architecture for distributed systems where real-time applications may run concurrently with non-real-time applications. The architecture uses a two-level scheduling scheme. Each application is assigned a sporadic server to schedule the processes in the application. All sporadic servers are then scheduled by a system-wide fixed priority scheduler. Using the proposed open environment architecture, all hard real-time applications are guaranteed to have their reserved CPU utilization in order to meet all their deadlines. The guarantee is independent of the behaviors of all other applications in the same system. We present the schedulability analysis methods on systems with or without shared memory.
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.
14056151
Distributed pinwheel scheduling with end-to-end timing constraints
Algorithms for allocating resources and scheduling tasks are important to the success of many real-time systems with end-to-end performance requirements. In this paper, an end-to-end scheduling model based on the pinwheel scheduling algorithms is presented for distributed real-time systems. We discuss how tasks on different nodes may be transformed to have harmonic periods. We also present algorithms to adjust the phases between schedules on neighboring nodes so that the overall end-to-end delay is reduced. Using the pinwheel approach, schedules on different nodes are closely synchronized and more static. However, for many real-time systems, this practical approach may provide a more predictable performance and a shorter end-to-end delay.
11605665
Implementing a general real-time scheduling framework in the RED-Linux real-time kernel
Many scheduling paradigms have been studied for real-time applications and real-time communication network. Among them, the most commonly used paradigms include priority-driven, time-driven and share-driven paradigms. In this paper, we present a general scheduling framework which is designed to integrate these paradigms in one framework. The framework is implemented in our real-time extension of the Linux kernel, RED-Linux. Two scheduler components are used in the framework: Allocator and Dispatcher. For each job, the framework identifies four scheduling attributes: priority, start time, finish time and budget. We show that the framework can be used to efficiently implement many well-known scheduling algorithms. We also measure and analyze the performance of the framework implemented in RED-Linux.
10903877
WISE-building simple intelligence into Web services
Web services are self contained and self described modular applications that can be published, discovered and employed on the Web. Many standard protocols supporting Web services have been adopted and more are being proposed. We study the issue on providing intelligent Web services. We propose the enhancement of Web service functionalities by deploying software agents on both server side and/or client side. Our goal of designing the WISE Web service architecture is to provide a working middle ground between the current Web service standards and the semantic Web architecture. The WISE software agent architecture for Web services is presented. We discuss the design issues of WISE. We also present the QoS management protocol and algorithm that can be used by WISE servers.
4707602
An initial strategy for comparing proteins at the domain architecture level
MOTIVATION
Ideally, only proteins that exhibit highly similar domain architectures should be compared with one another as homologues or be classified into a single family. By combining three different indices, the Jaccard index, the Goodman-Kruskal gamma function and the domain duplicate index, into a single similarity measure, we propose a method for comparing proteins based on their domain architectures.


RESULTS
Evaluation of the method using the eukaryotic orthologous groups of proteins (KOGs) database indicated that it allows the automatic and efficient comparison of multiple-domain proteins, which are usually refractory to classic approaches based on sequence similarity measures. As a case study, the PDZ and LRR_1 domains are used to demonstrate how proteins containing promiscuous domains can be clearly compared using our method. For the convenience of users, a web server was set up where three different query interfaces were implemented to compare different domain architectures or proteins with domain(s), and to identify the relationships among domain architectures within a given KOG from the Clusters of Orthologous Groups of Proteins database.


CONCLUSION
The approach we propose is suitable for estimating the similarity of domain architectures of proteins, especially those of multidomain proteins.


AVAILABILITY
http://cmb.bnu.edu.cn/pdart/.
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.
1387511
FastMap: a fast algorithm for indexing, data-mining and visualization of traditional and multimedia datasets
A very promising idea for fast searching in traditional and multimedia databases is to map objects into points in k-d space, using k feature-extraction functions, provided by a domain expert [25]. Thus, we can subsequently use highly fine-tuned spatial access methods (SAMs), to answer several types of queries, including the 'Query By Example' type (which translates to a range query); the 'all pairs' query (which translates to a spatial join [8]); the nearest-neighbor or best-match query, etc.However, designing feature extraction functions can be hard. It is relatively easier for a domain expert to assess the similarity/distance of two objects. Given only the distance information though, it is not obvious how to map objects into points.This is exactly the topic of this paper. We describe a fast algorithm to map objects into points in some k-dimensional space (k is user-defined), such that the dis-similarities are preserved. There are two benefits from this mapping: (a) efficient retrieval, in conjunction with a SAM, as discussed before and (b) visualization and data-mining: the objects can now be plotted as points in 2-d or 3-d space, revealing potential clusters, correlations among attributes and other regularities that data-mining is looking for.We introduce an older method from pattern recognition, namely, Multi-Dimensional Scaling (MDS) [51]; although unsuitable for indexing, we use it as yardstick for our method. Then, we propose a much faster algorithm to solve the problem in hand, while in addition it allows for indexing. Experiments on real and synthetic data indeed show that the proposed algorithm is significantly faster than MDS, (being linear, as opposed to quadratic, on the database size N), while it manages to preserve distances and the overall structure of the data-set.
5879747
Automatic information discovery from the "invisible Web"
A large amount of online information resides on the "invisible Web" - Web pages that are generated dynamically from databases and other data sources hidden from the user. They are not indexed by a static URL but are generated when queries are made via a search interface (a specialized search engine). In this paper, we propose a system that is capable of automatically making use of these specialized engines to find information on the invisible Web. We describe our overall architecture and process: from obtaining the search engines to picking the right engines to query. Experiments show that we can find information that is not found by traditional search engines.
9933111
Service-oriented computing
Service-oriented computing using Web services has emerged as a major research topic in recent years. Strong support from major computer companies including IBM, Microsoft, Hewlett-Packard, Oracle, and SAP has accelerated the acceptance and adoption of SOC using Web services. With SOC, enterprises can define and execute transactions across multiple business. Companies can use SOC's plug-and-play interoperability to compose business processes and integrate different information systems on the fly to enable ad hoc cooperation between new partners. Thus, SOC reinvents the way enterprises work together: common tasks in a business process or supply chain can be easily outsourced to external service providers for both performance and cost reasons.