Simplifying Control Flow in Compiler-Generated Parallel Code

Optimizing compilers for data-parallel languages such as High Performance Fortran perform a complex sequence of transformations. However, the effects of many transformations are not independent, which makes it challenging to generate high quality code. In particular, some transformations introduce conditional control flow, while others make some conditionals unnecessary by refining program context. Eliminating unnecessary conditional control flow during compilation can reduce code size and remove a source of overhead in the generated code. This paper describes algorithms to compute symbolic constraints on the values of expressions used in control predicates and to use these constraints to identify and remove unnecessary conditional control flow. These algorithms have been implemented in the Rice dHPF compiler and we show that these algorithms are effective in reducing the number of conditionals and the overall size of generated code. Finally, we describe a synergy between control flow simplification and data-parallel code generation based on loop splitting which achieves the effects of more narrow data-parallel compiler optimizations such as vector message pipelining and the use of overlap areas.     

Compilation of Constraint Programs with Noncyclic and Cyclic Dependencies to Procedural Parallel Programs

This paper reports on a compiler for translation of constraint specifications into procedural parallel programs. A constraint program in our system consists of a set of constraints and an input set containing a subset of the variables appearing in the constraints. The compiler described in this paper successfully compiles a substantially larger class of constraint specifications to efficient programs than did its predecessors. In particular the compiler has been extended to generate processor and memory efficient programs for cyclic constraints which can be resolved by computational relaxation methods. The paper first details the basic compilation process for noncyclic constraints. It then describes the additional steps in the compilation process which enable resolution of cyclic constraints to iterative computational processes and illustrates the process using derivation of a parallel program for solution of the Laplace equation as the example.     

Silicon-based miniature sensor for electrical tomography

The paper describes the fabrication of a novel miniature sensor for electrical tomography. The sensor comprises a number of copper electrodes that are fabricated around a small hole that is etched through a silicon wafer. Copper electrodes are electroplated to fill channels that are formed in thick photo-resist on top of the silicon wafer. Electrodes with a thickness of 60 μm, surrounding a hole of diameter 300 μm, have been realised. Initial measurements have been made using a commercial LCR meter applied to an eight-electrode sensor and images of a 80 μm diameter wire have been obtained. Future work will consider the integration of measurement circuitry alongside the electrodes in order to reduce parasitic capacitances.     

Data Architecture Standards for the Effective Enterprise

The modern enterprise has become increasingly dependent on data and its value-added forms of information and knowledge to remain competitive in the face of global competition and constant change. Data architecture provides the framework necessary to use and share data more effectively, and to improve the flow of data between systems within the enterprise and between the enterprise's systems and those of its customers, suppliers, and business partners. Data architecture standards constitute the foundation of an effective data architecture.     

IBM IntelliStation Z Pro

IBM IntelliStation Z Pro是IBM公司最新推出的图形工作站产品,它和最近推出的双路Opteron处理器IBMIntelliStation A Pro一样,并面向数字内容创建(DCC)市场.Z Pro配备2个英特尔至强CPU,支持英特尔64位内存扩展技术(EM64T),使32位至强CPU能够运行64位代码,并能够访问更多内存.Z Pro起始配置为2.8GHz至强处理器.本文将介绍IZ Pro的一些特点.     

Tropos: An Agent-Oriented Software Development Methodology

Our goal in this paper is to introduce and motivate a methodology, called Tropos,¹ for building agent oriented software systems. Tropos is based on two key ideas. First, the notion of agent and all related mentalistic notions (for instance goals and plans) are used in all phases of software development, from early analysis down to the actual implementation. Second, Tropos covers also the very early phases of requirements analysis, thus allowing for a deeper understanding of the environment where the software must operate, and of the kind of interactions that should occur between software and human agents. The methodology is illustrated with the help of a case study. The Tropos language for conceptual modeling is formalized in a metamodel described with a set of UML class diagrams.     

Stochastic unit commitment problem

The electric power industry is undergoing restructuring and deregulation. We need to incorporate the uncertainty of electric power demand or power generators into the unit commitment problem. The unit commitment problem is to determine the schedule of power generating units and the generating level of each unit. The objective is to minimize the operational cost which is given by the sum of the fuel cost and the start‐up cost. In this paper we propose a new algorithm for the stochastic unit commitment problem which is based on column generation approach. The algorithm continues adding schedules from the dual solution of the restricted linear master program until the algorithm cannot generate new schedules. The schedule generation problem is solved by the calculation of dynamic programming on the scenario tree.     

Automation of cytokine flow cytometry assays

Cytokine flow cytometry (CFC) is a multiparameter assay of antigen-specific T cell function, potentially useful in the monitoring of experimental vaccines and progression of infectious diseases and cancer. Automation of CFC assays would greatly facilitate their use in clinical trials and involves several components. We describe here the migration of these assays to 96-well plates, the use of sample-handling robotics, and the use of lyophilized antigen and antibody plates to help automate CFC. Together, these elements can produce an integrated system capable of walkaway automation of an entire assay, resulting in the reproducible processing of potentially hundreds of samples per day. Implementation of such systems has begun to be undertaken by our group and others.