Diagnostic Messages Research Articles

Software and transputer system design for high speed grading of agricultural produce

This paper reports some of the work done under a LINK (Design of High Speed Machinery Programme) project aimed at increasing the speed of produce grading. The computer platform was a transputer network with two special purpose hardware units and this paper covers the software system design and the organisation of the network topology. The software was designed on a modular basis and each module had facilities for sending diagnostic messages, timing sections of code, and sending debugging data through the system. The network topology reflected the flow of produce through the mechanical system and is basically a pipeline architecture with three parallel data streams. Timing requirements are discussed and results presented showing that the system will allow complex processing of data at throughputs of up to 80 objects per second.

A knowledge-based alarm processor for an energy management system

A novel station-oriented knowledge-based alarm processor prototype is presented. The knowledge-based system accesses a configuration database that contains information on both the topology of the power system and symbolic data values. Forward chaining rules are used to form hypothese when state changes occur on the power system. Backward chaining rules are used then attempt to prove each hypothesis using the current facts and the configuration database. Metalevel control rules improve system performance by selecting goals and doing context switching during the inference process. A rule-based management system is also introduced. The knowledge-based system continuously analyzes and processes SCADA (supervisory control and data acquisition) alarms in real time, presenting diagnostic messages to the power system operators without requiring any information from the operators. The prototype, written in the C programming language, resides on a stand-along computer with a data interface to the SCADA system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Control of Complex Industrial Processes — A Survey

The rapid growth of computerized information services with their easy, low cost accessibility via personal computers has greatly diminished the value of the traditional survey paper. In twenty minutes a search for papers on the subject of this survey disclosed ninety–one documented applications of control of complex industrial processes (See bibliography). Seventy–two of these discussed only the theory and methodology of the application. Twelve did not even give this much information discussing only the control theory which might be applicable. Only two of the remaining references gave a clear statement of the objectives of the control system and the degree to which they were achieved. In both cases, only partial success was realized. Unfortunately, the reasons for not accomplishing full success and plans as to how to improve the system were not discussed.It is this author's opinion that reporting on applications with -- at best -- in-complete information and inconclusive results is of marginal value to the IFAC community. Instead, the author has interviewed colleagues in process control to get information pertinent to the success or failure of classes of applications of control of complex industrial processes. Distributed and other advanced control computers are now being applied to complex industrial processes on a routine basis.But the system configurations and strategies being implemented with these powerful new technologies rarely do more than scratch the surface of the available hardware capabilities or control theory There are systems that document process performance and produce management reports, calculate values of variables such as composition or enthalpy that cannot be directly measured, show operators living pictures of the processor in full color using attention-attracting tricks ranging from three-dimensional representations to cartoon symbols, and offer control system designers configuration tools such as menu– driven choices of strategies and touchpad creation of process flow diagrams. And, there are hardware and software packages that offer fault–tolerant operation with diagnostic messages to assist maintenance people in finding and replacing failed components, networks that allow process computers and management information systems to freely exchange information, and programs that find the optimum tuning constants for three-mode controllers. But the flexibility inherent in the equipment is not being utilized effectively for departing from the constraints of control oriented toward single loops, nor for performing the calculations needed to utilize sophisticated process models for optimal multi-loop and other advanced control algorithms. And the ability of individual intelligent system modules to communicate with one another for control strategy integration and plant-wide coordination and optimization are not being employed meaningfully in spite of numerous opportunities to do so.

The Micro8 microcode assembler

This paper describes Micro8, a commercially-available microcode assembler written in ISO standard Pascal to enhance portability. Micro8 is designed to be a useful tool for both bit-slice and discrete logic designs. Considerable flexibility in definition of the microinstruction is provided to support both vertical and horizontal microwords. Debugging assistance is included in the form of a symbol cross reference listing, a map of control store locations, and diagnostic messages. Various features provided by the assembler are described, as are examples of typical microprogram sections.

A computer language for reducing activation analysis data

A program, written in FORTRAN, is described that defines a language for reducing activation analysis data. Communications are effected through commands, and these can be given in almost any order. Consistency checks are done and diagnostic messages are printed automatically to guard against the incorrect use of the commands. Default options on the commands allow instructions to be expressed concisely while providing a capability to specify details for the data reduction process. The program has been implemented on a UNIVAC 1108 computer.

The architecture of an ALGOL 60 computer implemented with distributed processors

In conventional computer systems, the computer hardware does not actually execute the user's source program. Instead, a software compiler and link editor transform the program into low level machine code which is executed by the hardware. This mapping from a high-level language to a von Neumann instruction set is a. Computationally costly because compilers and link editors are big and slow. b. Inefficient because the object code is generally poor. c. Error prone because compilers and link editors are difficult to design, debug, and maintain. Furthermore, diagnostic messages for execution errors (an arithmetic overflow for example) are either cryptic and require the user to be familiar with the machine language (i.e., a dump), or the object code generated must require considerable run time overhead to permit run time errors to refer back to the users source program (i.e., pointers and tables, etc.).

Compaction of diagnostic messages for compilers

AbstractThe use of a space optimal storage scheme for compiler diagnostic messages is described. The space reduction achievable through word coding may be predicted in terms of text length, vocabulary size and average word length. A method of word or phrase selection is discussed. Illustration is made by application to the FORTRAN FTN and COBOL compilers under the operating system KRONOS for the CDC 6400 computer.

Simulation of the steady-state and dynamic behaviour of multiple effect evaporation plants. Part 1: steady-state simulation

A computer program for design and evaluation calculations of general multiple effect evaporation plants has been developed. The computer program, called INDUNS, is based on the principles of modular composition of flowsheets of evaporation plants. With the aid of a unit cell, flowsheets of arbitrary complexity are easily handled. Flowsheet data is entered via a special connection matrix. Input of data for known variables, such as physical properties, is made by a set of mnemonic symbols in order to facilitate the input procedure. These symbols are also used in the data output procedure, thus giving a very clear output matrix. All input data is carefully examined by INDUNS. When errors are detected, self-explanatory diagnostic messages are printed out. Thus, the risk of feeding INDUNS with wrong or incomplete data is small. INDUNS has been thoroughly tested in calculations of industrial plants, in the sugar as well as in the pulp and paper industry. Recently, several runs were carried out in the design of a number of Swedish black liquor evaporation plants. In these calculations, a special subfunction for the estimation of the overall heat transfer coefficients was used, developed at the Department of Chemical Engineering at Chalmers University of Technology. The results from these calculations show that INDUNS is easy to handle even for very complicated plants. They also show that relatively little effort and reasonably short computer running times are required to carry out a series of alternative design calculations using an initially given set of data.

Quick compiler construction using uniform code generators

AbstractThis paper describes our experience in using a common set of code generating subroutines as the basis for compilers of ALGOL W, ALGOL 60 and subsets of PL/I and COBOL. The advantages of using a common set of primitives for implementing more than one compiler include: (1) greatly reduced effort to implement additional languages; (2) simplified maintenance of the generated compilers; (3) standardized diagnostic messages for all compilers implemented using this system; and (4) simplified documentation of the compilers.

The Generation Of Diagnostic Messages

AbstractThe techniques for the production of diagnostic messages through the use of a message generator are reviewed briefly. A detailed description of the implementation of such a message generator for the PLUTO PL/I student compiler is presented. Statistics on the performance of this generator are presented to show that significant savings in storage space are obtained while maintaining a very high level of program detail reporting in the diagnostic messages.

A step toward automatic analysis of student programming errors in a batch environment

The object of this investigation is to develop a method for the automatic collection of meaningful statistical information about the causes of program resubmittal in a batch-processing environment. Successive versions of a given program are compared statement-by-statement in order to isolate minor changes made in the program. All statements inserted, substituted, or deleted are examined in terms of (1) the type of statement (i.e. DO, IF, etc.), (2) the number of consecutive statements involved in the change, and (3) how many times the program has already been submitted (the number of “tries”). One thousand and one hundred and ten programs are analyzed in this manner. The method is intended to be used, in conjunction with detailed study of selected cases and with further experimentation in completely controlled situations, to improve programming instruction and manuals, to produce better diagnostic messages, to aid in the design of new compilers, and eventually, to provide means for automatic correction of trivial mistakes.

Information Management System: The Natural Dialogue System

The natural dialogue system (NDS) is a software system designed to permit the easy implementation of time-shared computer programs which employ sophisticated forms of man-machine dialogue to converse with members of a nonprogrammer user audience. The heart of the system is a syntax-directed translator which recognizes user input messages and translates them into an internal text of integers for use by the program. NDS allows the language designer to specify the syntax of the statements in his language, the form of their translations, methods for diagnosing errors in user's input, diagnostic messages to be generated, and the style of dialogue which will exist between the programs and their users. This is accomplished through a dialogue description and a language description consisting of syntactic specification elements with semantic procedures embedded within them. Use of NDS allows the language designer to produce an interactive language which is tailor-made for both his users and his programs. NDS relieves the language designer of the necessity of writing a complex message analyzer, thereby substantially reducing the effort required to produce systems that offer these forms of man-machine dialogue. Furthermore, use of NDS allows such systems to be implemented by less sophisticated programming talent than would otherwise be necessary.

Design and Application of Static Logic Directors

A digital computer program written by Westinghouse engineers aids the design of new static logic systems for metal mills. The computer program accepts logic equations specifying the functions to be performed. The program generates circuit drawings of logic circuitry plus paper tape for controlling an automatic wiring machine. The automatic wiring machine wires the back panel receptacles for plug-in cards which contain the integrated-circuit AND/NAND logic elements. The design engineer determines functional requirements to be performed by the logic circuits. He expresses these requirements in convenient logic statement form and adds comments on circuit functioning. Logic and comment statements are keypunched for input to the computer. The computer analyzes the equations, converts the functions to AND/ NAND logic circuits and generates the punched-paper tape required by the automatic wiring machine. In addition, the computer generates the circuit diagrams showing the actual AND/NAND circuits with complete (JIC) cross references and comments on circuit functioning. During computer processing diagnostic messages are generated to aid in finding design errors. Only one type of logic board is used in the new static logic system to perform all logic functions. This reduces maintenance to mere board replacement and greatly reduces spare board inventory. Triac outputs are featured in addition to normal contact closure outputs. Traic is a static ac switch which can operate pilot-operated solenoid valves, contactors, indicating lights, and other common ac loads. The logic system combines the advantages of fully wired integrated-circuit logic with the convenience and accuracy of computer aided design.

Common phrases and minimum-space text storage

A method for saving storage space for text strings, such as compiler diagnostic messages, is described. The method relies on hand selection of a set of text strings which are common to one or more messages. These phrases are then stored only once. The storage technique gives rise to a mathematical optimization problem: determine how each message should use the available phrases to minimize its storage requirement. This problem is nontrivial when phrases which overlap exist. However, a dynamic programming algorithm is presented which solves the problem in time which grows linearly with the number of characters in the text. Algorithm 444 applies to this paper.

A flexible computer program for calculations in emission-spectrographic analysis

A computer program has been written in FORTRAN IV to evaluate for spectrochemical analysis spectral information stored on photographic plates. With this program, ratios of line intensities are calculated from microphotometer readings; it includes the computation of the emulsion calibration function using either the two-step or seven-step method. A formatless data input technique is employed and use is made of descriptive headings and labels to facilitate the introduction of data. These headings and the codes used for labelling the readings are chosen so as to be readily understood by the spectrographer. The program is characterised by considerable flexibility with regard to the number of spectra and number of analytical and internal standard lines that can be used. The maximum number of spectra that can be evaluated is sixty and up to nineteen analytical lines can be present in each spectrum. The program contains many data checks, together with appropriate diagnostic messages, which are designed to avoid the presence of undetected errors in the results.