This paper presents a determinstic sorting algorithm, called Sharesort, that sorts n records on an n processor hypercube, shuffle-exchange or cube-connected cycles in O(log n(log log n)2) time in the worst case. The a...
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ISBN:
(纸本)0897913612
This paper presents a determinstic sorting algorithm, called Sharesort, that sorts n records on an n processor hypercube, shuffle-exchange or cube-connected cycles in O(log n(log log n)2) time in the worst case. The algorithm requires only a constant amount of storage at each processor. The fastest previous deterministic algorithm for this problem was bitonic sort, which runs in O(log2 n) time.
Object-Oriented Methods, Formal Specification Languages, Component-Based Software Production... This is just a very short list of technologies proposed to solve a very old and, at the same time, very well-known proble...
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ISBN:
(纸本)3540378715
Object-Oriented Methods, Formal Specification Languages, Component-Based Software Production... This is just a very short list of technologies proposed to solve a very old and, at the same time, very well-known problem: how to produce software of quality. programming has been the key task during the last 40 years, and the results have not been successful yet. This work will explore the need of facing a sound software production process from a different perspective: the non-programming perspective, where by non-programming we mainly mean modeling. Instead of talking about Extreme programming, we will introduce a Extreme Non-programming (Extreme Modeling-Oriented) approach. We will base our ideas on the intensive work done during the last years, oriented to the objective of generating code from a higher-level system specification, normally represented as a Conceptual Schema. Nowadays, though, the hip around MDA has given a new push to these strategies. New methods propose sound model transformations which cover all the different steps of a sound software production process from an Information systems Engineering point of view. This must include Organizational Modeling, Requirements Engineering, Conceptual Modeling and Model-Based Code Generation techniques. In this context, it seems that the time of Model Transformation Technologies is finally here...
We combine mixed integer linear programming (MILP) and constraint programming (CP) to minimize tardiness in planning and scheduling. Tasks are allocated to facilities using MILP and scheduled using CP, and the two are...
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ISBN:
(纸本)3540292381
We combine mixed integer linear programming (MILP) and constraint programming (CP) to minimize tardiness in planning and scheduling. Tasks are allocated to facilities using MILP and scheduled using CP, and the two are linked via logic-based Benders decomposition. We consider two objectives: minimizing the number of late tasks, and minimizing total tardiness. Our main theoretical contribution is a relaxation of the cumulative scheduling subproblem, which is critical to performance. We obtain substantial computational speedups relative to the state of the art in both MILP and CR We also obtain much better solutions for problems that cannot be solved to optimality.
Decision tables are modeled by a harmonium in a manner similar to P. Smolensky's implementation of the two-resistor circuit problem on a harmonium (1984). The lower units consist of the condition combinations, whi...
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Decision tables are modeled by a harmonium in a manner similar to P. Smolensky's implementation of the two-resistor circuit problem on a harmonium (1984). The lower units consist of the condition combinations, while the knowledge atoms are the actions that are to be carried out in response to the outcome of the conditions. Representational and knowledge vectors are defined. In general, some of the components of these vectors are known and the completion problem consists in filling in the rest of the values that are maximally consistent with the fixed features. The model is described by using harmony theory as the measure of goodness to accomplish the completion task. A comparison with more traditional structures for representing decision tables is made. It is argued that the harmonium is a more flexible and robust model, especially when the environment contains imperfect or incomplete situations.
In January 1991 the National Center for Health Statistics (NCHS) distributed their first CD-ROM. On this CD-ROM, the NCHS released 1987 data from the National Health Interview Survey (NHIS). Before the final version o...
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ISBN:
(纸本)0780304829
In January 1991 the National Center for Health Statistics (NCHS) distributed their first CD-ROM. On this CD-ROM, the NCHS released 1987 data from the National Health Interview Survey (NHIS). Before the final version of the 1987 NHIS CD-ROM was distributed, an abbreviated CD-ROM was beta tested. The author presents some of the information obtained from the beta test, findings that focus on developing the user interfaces within the constraints of using a CD-ROM for statistics on a desktop computer. Findings from the beta test indicate that users benefit from five different interfaces that can be used in any sequence and with any frequency: paper documentation, online reference documents, dialogue boxes, help screens, and simultaneous translation of values and codes.
Poorly structured code is hard to maintain and read Program refactoring can improve code structure and thus make it easier to preserve and to discern the underlying design. However, refactoring is a difficult and time...
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ISBN:
(纸本)0769524656
Poorly structured code is hard to maintain and read Program refactoring can improve code structure and thus make it easier to preserve and to discern the underlying design. However, refactoring is a difficult and time-consuming process making it unattractive for many developers. An automated tool that could identify poorly structured code and make suggest ions would make the refactoring process easier. Although in general refactorings may be quite difficult to locate automatically, we show that many can be detected using low-cost, syntactic techniques. We have built a tool to locate refactorings in C# programs. Our experiments indicate that the tool has an excellent success rate in identifying refactorings.
Atomicity is an important generic specification that assures that a programmer can pretend blocks occur sequentially in any execution. We define a notion of atomicity based on causality. We model the control flow of a...
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ISBN:
(纸本)354037406X
Atomicity is an important generic specification that assures that a programmer can pretend blocks occur sequentially in any execution. We define a notion of atomicity based on causality. We model the control flow of a program with threads using a Petri net that naturally abstracts data, and faithfully captures the independence and interaction between threads. The causality between events in the partially ordered executions of the Petri net is used to define the notion of causal atomicity. We show that causal atomicity is a robust notion that many correct programs adopt, and show how we can effectively check causal atomicity using Petri net tools based on unfoldings, which exploit the concurrency in the net to yield automatic partial-order reduction in the state-space.
We explore the nature of the interaction between organisational culture and XP practice via three empirically-based case studies. The case studies cover a spectrum of organisational cultures. Our findings suggest that...
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ISBN:
(纸本)0769524877
We explore the nature of the interaction between organisational culture and XP practice via three empirically-based case studies. The case studies cover a spectrum of organisational cultures. Our findings suggest that XP can thrive in a range of organisational cultures and that the interaction between organisational culture and XP can be complex & subtle, with consequences for practice.
This paper describes a methodology for developing processor specific tools such as assemblers, disassemblers, processor simulators, compilers etc., using processor models in a generic way. The processor models are wri...
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ISBN:
(纸本)0769506682
This paper describes a methodology for developing processor specific tools such as assemblers, disassemblers, processor simulators, compilers etc., using processor models in a generic way. The processor models are written in a language called Sim-nML [1] which is powerful enough to capture the instruction set architecture of a processor. We describe a few tools in this paper which can be retargeted to any processor using the high level Sim-nML model of the processor.
A method for measuring data locality in four common sorting algorithms is investigated. A modification of the heap data structure exhibiting improved locality is also introduced.
ISBN:
(纸本)0897913485
A method for measuring data locality in four common sorting algorithms is investigated. A modification of the heap data structure exhibiting improved locality is also introduced.
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