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961.
The paper sets out to offer an alternative to the function/argument approach to the most essential aspects of natural language meanings. That is, we question the assumption that semantic completeness (of, e.g., propositions) or incompleteness (of, e.g., predicates) exactly replicate the corresponding grammatical concepts (of, e.g., sentences and verbs, respectively). We argue that even if one gives up this assumption, it is still possible to keep the compositionality of the semantic interpretation of simple predicate/argument structures. In our opinion, compositionality presupposes that we are able to compare arbitrary meanings in term of information content. This is why our proposal relies on an ‘intrinsically’ type free algebraic semantic theory. The basic entities in our models are neither individuals, nor eventualities, nor their properties, but ‘pieces of evidence’ for believing in the ‘truth’ or ‘existence’ or ‘identity’ of any kind of phenomenon. Our formal language contains a single binary non-associative constructor used for creating structured complex terms representing arbitrary phenomena. We give a finite Hilbert-style axiomatisation and a decision algorithm for the entailment problem of the suggested system.  相似文献   
962.
This paper defines a type of constrained artificial neural network (ANN) that enables analytical certification arguments whilst retaining valuable performance characteristics. Previous work has defined a safety lifecycle for ANNs without detailing a specific neural model. Building on this previous work, the underpinning of the devised model is based upon an existing neuro-fuzzy system called the fuzzy self-organising map (FSOM). The FSOM is type of ‘hybrid’ ANN which allows behaviour to be described qualitatively and quantitatively using meaningful expressions. Safety of the FSOM is argued through adherence to safety requirements—derived from hazard analysis and expressed using safety constraints. The approach enables the construction of compelling (product-based) arguments for mitigation of potential failure modes associated with the FSOM. The constrained FSOM has been termed a ‘safety critical artificial neural network’ (SCANN). The SCANN can be used for non-linear function approximation and allows certified learning and generalisation for high criticality roles. A discussion of benefits for real-world applications is also presented.  相似文献   
963.
This paper addresses the utilization of traces taken from MPI applications to do simulation-based performance studies of parallel computing systems. Different mechanisms to capture traces are discussed, pointing out important limitations of some of them. One of these limitations is the invisibility of message interchanges in collective operations, which is circumvented modifying a trace-capturing library. During a simulation, trace records must be simulated in causal order, to fully comply with application semantics. Alternatives to follow this order, and the risks of not following it, are presented and discussed. The techniques introduced in this paper have been implemented in an in-house developed simulation environment, which is used in two example studies to show its usefulness: an evaluation of alternatives for interconnection network design, and a performance prediction study in which traces from one machine are used to estimate the execution times of applications running in a different machine.  相似文献   
964.
The rate of scientific discovery can be accelerated through computation and visualization. This acceleration results from the synergy of expertise, computing tools, and hardware for enabling high-performance computation, information science, and visualization that is provided by a team of computation and visualization scientists collaborating in a peer-to-peer effort with the research scientists.In the context of this discussion, high performance refers to capabilities beyond the current state of the art in desktop computing. To be effective in this arena, a team comprising a critical mass of talent, parallel computing techniques, visualization algorithms, advanced visualization hardware, and a recurring investment is required to stay beyond the desktop capabilities.This article describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing and visualization to accelerate condensate modeling, (2) fluid flow in porous materials and in other complex geometries, (3) flows in suspensions, (4) x-ray absorption, (5) dielectric breakdown modeling, and (6) dendritic growth in alloys.  相似文献   
965.
油井深抽过泵产液剖面测试技术   总被引:1,自引:0,他引:1  
为准确找出油井的出水层段,研究了深抽过泵产液剖面测试技术。该工艺技术在油井检泵作业施工期间.进行,在井下2000m以内套管上悬挂空心测试抽汲泵,通过油管驱动深抽产液,测试仪器从油管下入并过泵柱塞到达测试层段,进行不停抽测试,得到产液剖面资料,判断出主产水层,进行有针对性的卡堵水作业。适用于斜井、稠油井、螺杆泵井、电潜泵井、水力泵井等无法进行环空测试的油井。在华北油田成功实施了50余井次,为油田开发方案的判定提供了较为准确的资料。  相似文献   
966.
We compare the performance of three major programming models on a modern, 64-processor hardware cache-coherent machine, one of the two major types of platforms upon which high-performance computing is converging. We focus on applications that are either regular, predictable or at least do not require fine-grained dynamic replication of irregularly accessed data. Within this class, we use programs with a range of important communication patterns. We examine whether the basic parallel algorithm and communication structuring approaches needed for best performance are similar or different among the models, whether some models have substantial performance advantages over others as problem size and number of processors change, what the sources of these performance differences are, where the programs spend their time, and whether substantial improvements can be obtained by modifying either the application programming interfaces or the implementations of the programming models on this type of tightly-coupled multiprocessor platform.  相似文献   
967.
以辽宁省西丰县诚信水库水资源论证为例,通过对新建建设项目取水、用水、退水的合理性以及对水环境和他人合法权益的影响进行综合分析论证,探讨了建设项目取水的保证程度,提出了新建中小型水库水资源论证的方法。  相似文献   
968.
尚灵 《山东冶金》2001,23(3):41-43
在满足工艺技术要求的前提条件下,通过对350m^3高炉冲渣转鼓滤渣在数的理论计算,选择并适合系统运行数据,证明了系统的可行性,保证了系统在设计工艺参数、设备参数状态下的正常运行。  相似文献   
969.
M. Das 《ISA transactions》2009,48(1):122-131
Modern day process control uses digital controllers which are based on the principle of distributed rather than centralized control. Distributing controllers, sensors and actuators across a plant entails considerable wiring which can be reduced substantially by integrating the components of a control loop over a network. The other advantages include greater flexibility and higher reliability with lower hardware redundancy. The controllers and sensors are on a network and can take over the function of a failed component automatically, without the need of manual reconfiguration, thus eliminating the need of having a redundant component for each and every component. Though elaborate techniques have been developed for Single Input Single Output (SISO) systems, the major challenge lies in extending these ideas to control a practical process plant where de-centralized control is actually achieved through control of individual SISO control loops derived through de-coupling of the original system. Multiple loops increase network load and hence the sampling times associated with the control loops and makes synchronization difficult. This paper presents a methodology by which network based process control can be applied to practical process plants, with a simple direct synchronization mechanism.  相似文献   
970.
介绍了PC机群系统的主要特性及其相关技术。介绍了构造高可用、高流量、可扩展机群系统的硬件要求、系统软件及编程环境 ,讨论了在其上分布并行计算的一些概念和需要解决的问题。  相似文献   
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