Raphael B. Yehezkael

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Our proposal has the following key features: 1) The separation of a distributed program into a pure algorithm (PurAl) and a distribution/communication declaration (DUAL). This yields flexible programs capable of handling different kinds of data/program distribution with no change to the pure algorithm. 2) Implicit or automatic handling of communication via(More)
First courses in computer science usually deal with sequential algorithms and programs. Unfortunately, this gets students accustomed to sequential thinking, making it hard for them to understand and effectively use parallelism later. On the other hand, because parallel programming is so difficult, introducing it at an early stage is impractical. So, my(More)
Techniques are presented for ensuring well-defined parallel and unordered sequential execution (flexible execution), where values read are independent of the permitted execution orders. This is done by refining the scope rules of variables and defining where they may be initialized, where they may be updated, and where they may be read. Given these refined(More)
As a deterministic parallel programming language that guarantees safety of parallel executions, EFL was designed to allow the embedding of parallel code blocks into a sequential host language program. An EFL pre-compiler, which is described here, has been implemented that translates EFL blocks into the host language. The EFL pre-compiler and runtime(More)
The purpose of this work is to classify parallel automata conflicts, to develop techniques for handling conflicts a-priori and a-posteriori, and to analyze the complexity of conflicts and other problems concerning parallel automata. Synchronous parallel automata having inputs and outputs, and which are useful for designing real time systems will be(More)
We present in this paper a methodology how to use 'Parallel Automaton' to set up the requirements, to specify and to execute small Computer Based Systems (CBS). A 'Parallel Automaton' is an extended form of the Mealy Machine. It handles a finite set of events (or variable conditions or clock conditions) which can occur in parallel, and performs a finite set(More)
This article presents an overview of a beginner's course on flexible algorithms. We briefly describe this notation's main features and present fragments from this course. The core algorithmic notation of flexible algorithms is based on functions with In parameters and Out parameters (but no In/Out parameters) and conditional statements. As in mathematics,(More)
We define and classify a family of parallel automata (for Real-Time and Telecommunication modeling) in the context of a synchronous execution. First, an abstract form of Parallel automata is proposed as a generalization of various "Extended-Finite-statesMachines" found in the literature. Then, two implementable forms of Parallel Automata are presented : A(More)
In an earlier paper (Yehezkael 1991), computational tests and a computer simulation were used to quantitatively assess inaccuracies of several price index formulae. In this paper the analytic approach for assessing these inaccuracies is developed and is found to be in good agreement with the estimates obtained computationally in our earlier paper. The(More)
Here flexible algorithms are used for teaching purposes in a course for beginners. Flexible algorithms have a simple notation and are multifaceted. They may be executed in a variety of orders, sequential or parallel, producing results independent of the execution order. They may be converted to sequential algorithms and to hardware block diagrams. They may(More)