John R. Metzner

Generating an autocorrelated sequence of random variates without distorting their distribution

Using moving averages to introduce autocorrelation into a sequence of pseudorandom variables will most often distort the shape of the distribution. When the correlation coefficients are to be zero from some lag onward, it is possible to compensate for most of the distortion by starting with variates from another distribution. It is shown how to calculate the moving average coefficients and the parameters of the basic sequence so as to achieve the desired autocorrelation while retaining fidelity with the desired distribution to four moments. The moving average approach yields an internal generation method having quite modest storage requirements.

PROGRAMMING LANGUAGE FEATURES

Processors exist for a variety of decision table languages. This chapter discusses these characteristics. The features are grouped into five categories according to their sphere of primary impact: outer language, syntax, semantics, implementation, and convenience. The group of features is concerned with the surrounding languages that may contain decision tables as linguistic elements. The simplest and common type of outer language consists of an existing programming language to which decision tables have been grafted. The decision tables are treated as blocks of imperative code in the programming language. The programming language is augmented with new verbs to facilitate transfers of control to and from the blocks represented by tables. The same procedure-oriented programming language is used within the decision tables as the base language. It is the object language produced by pre-processor implementations. This ubiquitous programming language is called the host language of the decision table programming system.

An inherently parlle large grained data flow environment

A parallel programming environment based on data flow is described. Programming in the environment involves use with an interactive graphic editor which facilitates the construction of a program graph consisting of modules, ports, paths and triggers. Parallelism is inherent since data presence allows many modules to execute concurrently. The graph is executed directly without transformation to traditional representations. The environment supports programming at a very high level as opposed to parallelism at the individual instruction level.

Development of a parallel algorithmic language (abstract only)

Rolla* - A new style of programming is needed to meet the increased demands of computational speed. A software system based on dataflow and designed to use parallelism in future architectures is envisioned. The language model is designed so that any algorithm can be easily communicated to both man and machine. The basic entity of the model is that of units which are interconnected by a series of data paths like pipes. A unit is any process, file or device capable of consuming or supplying data. Consuming and supplying pairs are categorized by the type of flow of data between units. A notation has been developed to express the dataflow graphs which exposes the parallel nature of the model. Ports, index numbers and process names allow an unambiguous representation of the graphs and support nesting to any level. Further research is being done in the area of unit description and dataflow control.

Contesting (Panel Discussion)

Contest activity can be staged in a wide variety of ways and the features of a contest design can be drawn from wide spectra of possibilities. The participants can be brought together for the contest or can stay home and send their programs to the contest; they can be from any level of expertise from high school student to professional programmer. A contest can reward producing a solution program in the shortest time or can be scored on bases like originality and program quality; it can focus upon any aspect of the programming process from algorithm synthesis to debugging or program modification. The panel will expose and explore the ranges of possible contest design features by describing the structures and workings of contests they have supervised. Each of the features mentioned above is represented in the contest experience of one or more members of this panel. The experiences gained in a diverse set of contests will be related to base a discussion of problems encountered and drawbacks noted as well as of strong points and alternative contest features that have been brought to mind but not yet tried out. The set of contests includes ACMs Regional and National Contests at the collegiate level for teams of four in a batch environment, team selection and training contests, an interactive BASIC contest for teams, the interactive individual contest at the 1977 NCC, a countywide contest for teams of high school students, and the well-established AEDS mail-in contest for secondary students.

CHAPTER 4 – GENERALIZATION

Publisher Summary This chapter presents an incomplete exploration of the possibilities for the development of decision table programming through generalizing the features because neither the diversity nor the extent of that development is limited. An evaluation of features is involved: some are rejected as counterproductive to improvement, and others adjudged unproductive. It is not possible to separate the processes of generalization and innovation. In the form of transplants of familiar concepts into different settings, innovation enters as inspiration to generalization and as exemplification of it. Many of the improvements can be used in alternative forms and ways or may be considered for optional inclusion in decision table programming systems. Judgments on the appropriate forms of features or the desirability of their inclusion can be made during design, in the light of goals, constraints, and other features selected.

CHAPTER 2 – SEMIOTICS

Publisher Summary This chapter discusses semiotics. Like most other languages, decision table languages have multiple dialects, which fall into two groups depending upon whether they are used for human-to-human communication or for human-to-machine communication. Documentation languages tend to be informal and may include graphic devices such as flow charts, while programming languages are defined by their processors. In all decision table languages, the decision table appears as a language element. Even in the languages that appear to consist of decision tables, there must be an outer language mechanism for grouping sets of related tables and indicating the one that is to be operative first. This outer language contains a syntactic type allowing the syntactic description of permissible decision tables to be separated from the syntactic description of the remainder of the outer language. It is appropriate to consider the syntax for a single, isolated decision table. The semantics of outer language, decision tables, and base language are partially separable. The outer language determines the semantic context of the invocation of each decision table and that of the resulting execution of the actions it selects.

CHAPTER 5 – DESIGN IMPLICATIONS

Publisher Summary The features of decision table programming systems cannot be evaluated outside a system context. The contribution of a particular feature toward the goals and purposes of the entire system is conditioned by its operation in conjunction with the other features comprising the programming system. The situation, termed as the system designers dilemma, leads to an iterative procedure in which a starting point is chosen, and components are then added, deleted, and exchanged until no improvement can be obtained. The starting system is a minimal set of essential components. Because only limited backtracking is performed, the remaining components are examined in order of decreasing anticipated value to the system. The selection of essential features and the ordering of the remainder are subjective even though conditioned by the goals and constraints of the entire system. This chapter presents a relative evaluation of the features of decision table programming by estimating the point at which they would enter the iterative design process.