H∞-control with measurement-feedback for Pritchard-Salamon systems

In this paper we extend the finite-dimensional results for the H_∞-control problem with measurement-feedback to a large class of infinite-dimensional systems, allowing for a certain type of unboundedness in the input and output operators (the Pritchard-Salamon class). The main result of the paper relates the solvability to the suboptimal H_∞-control problem to the existence of stabilizing solutions to certain operator Riccati equations. Furthermore, a characterization of all suboptimal controllers is given.     

An explicit finite difference method for finite-time observers

In this paper we present a numerical method for estimating the current state of a nonlinear control system. We use finite differences to discretize a modified version of the finite-time observer equations in James. The discretized equations are simple and easily programmed. The convergence and accuracy of the scheme is proved, and the scheme enjoys a number of important properties: availability of rate of convergence estimates, good robustness characteristics, and the ability to handle certain types of discontinuities in the observations. The major disadvantage is that the number of grid points required increases exponentially with the number of state dimensions.     

Management of multidimensional discrete data

Spatial database management involves two main categories of data: vector and raster data. The former has received a lot of in-depth investigation; the latter still lacks a sound framework. Current DBMSs either regard raster data as pure byte sequences where the DBMS has no knowledge about the underlying semantics, or they do not complement array structures with storage mechanisms suitable for huge arrays, or they are designed as specialized systems with sophisticated imaging functionality, but no general database capabilities (e.g., a query language). Many types of array data will require database support in the future, notably 2-D images, audio data and general signal-time series (1-D), animations (3-D), static or time-variant voxel fields (3-D and 4-D), and the ISO/IEC PIKS (Programmer's Imaging Kernel System) BasicImage type (5-D). In this article, we propose a comprehensive support ofmultidimensional discrete data (MDD) in databases, including operations on arrays of arbitrary size over arbitrary data types. A set of requirements is developed, a small set of language constructs is proposed (based on a formal algebraic semantics), and a novel MDD architecture is outlined to provide the basis for efficient MDD query evaluation.     

井场信息系统建设体系结构

对井场钻井数据实时远程传输的研究和实践进行了总结,从数据远传作用、数据远传通信方式、数据通信网络体系结构、未来发展等几个方面对井场数据远程传输进行了探讨。     

大坝安全监控专家系统中的知识处理

在介绍产生式规则及其数学模型的基础上，论述了用成熟的关系数据库 技术来表示和存储产生式规则表示的专家知识的方法，较好地解决了知识的存储和管理问题 。同时，利用关系数据库中实体间的关系，很容易将分散存储的规则元素组合成规则供推理 时使用。在分析了大坝安全监控专家系统知识特点的基础上举例说明了用关系数据库表 示产生式规则的具体方法。     

An Effective Software Pipelining Algorithm for Clustered Embedded VLIW Processors

This paper proposes a software pipelining framework, CALiBeR (ClusterAware Load Balancing Retiming Algorithm), suitable for compilers targetingclustered embedded VLIW processors. CALiBeR can be used by embedded systemdesigners to explore different code optimization alternatives, that is, high-qualitycustomized retiming solutions for desired throughput and program memory sizerequirements, while minimizing register pressure. An extensive set of experimentalresults is presented, demonstrating that our algorithm compares favorablywith one of the best state-of-the-art algorithms, achieving up to 50% improvementin performance and up to 47% improvement in register requirements. In orderto empirically assess the effectiveness of clustering for high ILP applications,additional experiments are presented contrasting the performance achievedby software pipelined kernels executing on clustered and on centralized machines.     

Information systems and uncertainty: a conspiracy of misplaced confidence

Abstract. Information technology is becoming an increasingly important factor in contemporary management. Information systems are being set up in business explicitly to accommodate the new opportunities of this technology, and these are having a lasting effect on managerial practice. The full implications of this technology-driven development have not been appreciated by organizations, which in absorbing technological systems, are tolerating a great drain on their resources.
The efficacy of computers is predicated on the acceptance of some very specific perspectives. A growing discontent and disappointment with their limited achievements is our reason for advocating a different point of view. We will discuss how a shift in perspective, particularly in respect to the perception of uncertainty, will affect thinking and practice in the field of management support systems. We will render our view of the application of computerized decision support systems (DSS), and especially, we will focus on the beliefs and assumptions that have shaped this technology thus far. To this end we will discuss the concept of uncertainty, by juxtaposing current thinking and practice with our understanding of the context of its application. Finally, we will place our understanding of uncertainty in a managerial context and explain the implications this would have for strategists.     

基于ASP技术实现网上购物系统

利用目前流行的一种Web应用开发技术-ASP，实现网上购物系统。应用了ASP对COM组件的支持，实现了异构数据库的联合使用。同时，此系统具备客户登录功能，利用于系统的安全性。     

Object-oriented DBMS requirements

The requirements on an object-oriented DBMS for management of information in a large, complex enterprise are presented. These requirements aid in the achievement of an environment characterized by data sharing, open architectures, application and data portability, and assurance of data integrity. They were defined from the point of view of a user of the DBMS; therefore they describe the expected functionality of the DBMS and do not specify the method of implementation to achieve this functionality. They encompass requirements on the data model, query and data manipulation languages, the system architecure, interfaces to the system, change management, and transaction management.