Avoiding Knotty Structures in Design: Schematic Functional Programming

Designers in general have used diagrams and sketches to help in the process of creation. This is particularly so for system designers whose output is a set of programs. It would seem reasonable that the conversion of diagrams directly into a program would be desirable and yet the work of Green and Petre [3–4, 13] and Citrin [2] has placed doubt on the viability of graphical programming notations. Some of this work is reviewed in this paper. The use of secondary notation and the matc–mismatch hypothesis is reconsidered in the light of functional programming. It is proposed that much of the criticism of graphical notation is due to the imperative (or process orientated) nature of programming. Many of the limitations observed in using graphical notation are lifted when functional programming is used. Eight engineering dimensions and four engineering relationships (coherences) are proposed to describe programming environments (including notation). The source of ‘knotty structures’ is identified as embedded ‘if then else’ or ‘if’ statements. On analysing both imperative and functional programs it was found that imperative programs used an order of magnitude larger number of ‘if’s than functional programs. The key to the success of a functional language as a general representation as well as its coherence with a graphical notation comes from its unique extensibility. Support for these arguments is drawn from examples of a schematic programming language used for industrial scale projects. It is concluded that the marriage between a functional language and its graphical representation overcomes most of the original criticisms of graphical programming. It is demonstrated that this combination makes a viable and expressive tool for industrial-sized applications.     

Control and design problems in material processing—how can process systems engineers contribute to material processing?

‘Process control and systems engineering’ is not just a subject of study for controlling and designing ‘a plant’ and/or ‘a unit operation’. It also deals with any control and design problems related to physical and chemical phenomena occurring in short time-scale and at nano, meso as well as micro-scale levels. In materials processing, controlling the material structure is of primary importance for realizing high material performance and functions. The phenomena determining the material structure often involve phase separation and/or occur on the surface of the materials, at small level and in short time-scale. To control these phenomena, the current feedback design schemes, where controlled variables are measured by ‘externally equipped sensors’ and fed back to a ‘externally designed controller’, are no longer effective due to the shortness of time and smallness of spatial scales of the objects. Making reference to two novel polymer-processing processes, a micro-cellular polymeric foaming process and surface coating injection-molding process, we discuss how process control and process systems engineers can contribute to controlling the structure of materials.     

EPS: An ‘elementary’ programming system for the Delft Parallel Processor

A programming system for synchronous parallel processors, like the DPP-84 working in synchronous mode, is proposed. In EPS a program consists of a collection of well-defined and separate units, described in a conventional procedure-oriented language like PASCAL or MODULA-2. The connection between the ‘elementary’ program units is laid in a supervisory ‘configuration’ program, which defines both the spatial and time relations between the units. The concept of ‘virtual’ parallel processing is introduced, which enables the construction of logical parallel programs, independent of the number of processing elements actually available.     

The stuttering principle revisited

It is known that LTL formulae without the ‘next’ operator are invariant under the so-called stutter equivalence of words. In this paper we extend this principle to general LTL formulae with given nesting depths of both ‘next’ and ‘until’ operators. This allows us to prove the semantical strictness of three natural hierarchies of LTL formulae, which are parametrized either by the nesting depth of just one of the two operators, or by both of them. Further, we provide an effective characterization of languages definable by LTL formulae with a bounded nesting depth of the ‘next’ operator.This paper is a revised and extended version of [6].     

Leogo: An Equal Opportunity User Interface for Programming

Leogo is a novel programming environment supporting an ‘equal opportunity’ user interface which allows users to express their programming tasks through any mixture of three concurrently active programming paradigms: by direct-manipulation using ‘programming by demonstration’, by clicking buttons and dragging sliders in an iconic language and by typing commands in a normal text-based language. Equal opportunity ensures that the effects of any interface action are simultaneously displayed across each of the three paradigms—input expressions in one paradigm cause output of equivalent expressions in the other two paradigms. Leogo is designed to promote programming skills in primary and junior schools, but the interface properties it demonstrates are applicable to a wide range of novel programming environments. Leogo's motivation, design, development and preliminary usability study are described.     

Miro: visual specification of security

Miro is a set of languages and tools that support the visual specification of file system security. Two visual languages are presented: the instance language, which allows specification of file system access, and the constraint language, which allows specification of security policies. Miro visual languages and tools are used to specify security configurations. A visual language is one whose entities are graphical, such as boxes and arrows, specifying means stating independently of any implementation the desired properties of a system. Security means file system protection: ensuring that files are protected from unauthorized access and granting privileges to some users, but not others. Tools implemented and examples of how these languages can be applied to real security specification problems are described     

Logic programming for process planning in the domain of sheet metal forming with progressive dies

In this work an intelligent system pertaining to sheet metal part and process design has been developed, storing knowledge and prescribing ways to use this knowledge according to the ‘programming in logic’ paradigm. The sheet metal parts covered by the software are those having U shape and being manufactured by bending (folding), cutting and piercing with particular emphasis on progressive dies. The use envisaged and corresponding parts of the system are: checking the part design for manufacturability, planning process phases, and checking the configuration of press tools involved. Particular attention is paid to the presentation of knowledge that has been gathered from handbooks and verified / enhanced in industry. This is first presented in natural language and then its formal representation in Prolog is described and explained by examples. Part design and press tool checking knowledge is relatively straightforward to represent and structure ‘linearly’. Process planning knowledge is based on patterns that are captured in lists and activated in a case-by-case fashion exploiting the power of Prolog. Validation of the system was conducted using examples from industry.     

A sensitivity formula for risk-sensitive cost and the actor–critic algorithm

We propose for risk sensitive control of finite Markov chains a counterpart of the popular ‘actor–critic’ algorithm for classical Markov decision processes. The algorithm is based on a ‘sensitivity formula’ for the risk sensitive cost and is shown to converge with probability one to the desired solution. The proof technique is an adaptation of the ordinary differential equations approach for the analysis of two time-scale stochastic approximation algorithms.     

The role of student learning styles, gender, attitudes and perceptions on information and communication technology assisted learning

The present study adopts an illuminative approach to evaluate students’ initial attitudes towards the use of information and communication technology (ICT). Ninety-nine undergraduate science students participated in this study and their learning styles were classified according to Honey and Mumford (1986) (Honey, P., Mumford, A., 1986. The Manual of Learning styles. Peter Honey, 10 Linden Avenue, Maidenhead) learning style questionnaire. Student learning styles were classified as activist, reflector, theorist, or pragmatist. No significant difference in learning styles was observed between genders and between student cohorts. Six dimensions to student attitudes toward ICT were identified as follows; ‘comfort’, ‘interactivity’, ‘self-satisfaction’, ‘value new technology’, ‘experience’ and ‘context’. Students exhibited low scores in the attitude dimensions of ‘value new technology’, ‘interactivity’ and ‘context’ indicating that they were uncomfortable with computers, were unhappy about the lack of personal contact and would prefer to learn in a more traditional mode. A significant, though weak, negative correlation between the ‘theorist’ and the ‘interactivity’ and ‘context’ attitude dimensions was also observed. In addition, based on the results of this study it appears that first year students exhibit a more positive perception of ICT supported learning than second and third year students. Though the use of ICT in higher education is becoming more widespread based on the results of this study student use of the technology may be limited by a negative attitude toward a style of teaching which is not consistent with their past learning experiences.     

The design and implementation of the GINO 3D graphics software package

The design and implementation of a general purpose graphics software package (GINO) is described. GINO provides facilities for 3D graphics (co-ordinate transformation, clipping, intensity modulation) but is organized so that 2D facilities form a clean subset. It is device independent, permitting use of refresh CRT displays, storage tube displays and plotters. A characteristic feature is the use of small satellite computers attached to a large multiaccess computer (ATLAS 2) GINO takes the form of a subroutine library accessible from FORTRAN and other languages, and the case for this level of graphics software is argued. The reasons for not using a mandatory graphical data structure are also discussed. GINO is not biased towards any particular style of interaction, but two techniques are described; one based on the light pen and the other on teletype command languages Efficiency of implementation is achieved without loss of flexibility by use of a systems programming language (SAL).     

Towards a Programming Language for Interaction Nets

Interaction nets were introduced almost 15 years ago. Since then they have been put forward as both a graphical programming paradigm and as an intermediate language into which we can compile other languages. Whichever way we use interaction nets, a problem remains in that the language is very primitive. Drawing an analogy with functional programming, we have the λ-calculus but we are missing the functional programming language: syntactic sugar, language constructs, data-structures, etc. The purpose of this paper is to make a first step towards defining such a programming language for interaction nets.     

A new class of intelligent knowledge-based systems with an optimisation-based inference engine

In this paper we describe a new class of intelligent knowledge-based system (IKBS) which can be used principally for managerial decision making applications. This class of applications often requires a framework for knowledge acquisition which allows the system to use the knowledge of several experts. In addition, since in most business decision making the objective is maximise profits, there is a need for an inference engine which allows optimisation to be carried out. The new class of IKBS which is described in this paper has both these properties, i.e., the ability to use the knowledge of multiple experts in a convenient way and an inference engine which by performing optimisations is able to pick out the profit maximising decisions. As an illustration of these concepts, a system for allocation decision making is described. The system ‘Retail-opt’ allows the user to solve problems like allocation of space in retail outlets, allocation of space in mail order catalogues, pricing policy decisions for discounted airline tickets, etc. In the paper, the basic concepts behind ‘Retail-opt’ are described and an application of ‘Retail-opt’ to the problem of retail space allocation in a Scandinavian Department Store is given. A number of other systems which use these concepts for more complicated competitive decision making situations are also described.     

Implementation of visual languages using pattern‐based specifications

The implementation of visual languages requires a wide range of conceptual and technical knowledge from issues of user interface design and graphical implementation to aspects of analysis and transformation for languages in general. We present a powerful toolset that incorporates such knowledge. Our toolset generates editors from high‐level specifications. A language is specified by identifying certain patterns in the language structure and selecting a visual representation from a set of precoined solutions. Visual programs are represented by attributed abstract trees. Therefore, further phases of processing visual programs can be generated by state‐of‐the‐art tools for language implementation. We demonstrate that even challenging visual languages can be implemented with reasonably little effort and with rather limited technical knowledge. The approach is suitable for a large variety of visual language styles. Copyright © 2003 John Wiley & Sons, Ltd.     

A qualitative temporal information system for process control

A general system is presented in this paper which supports the expression of relative temporal knowledge in process control and management. This system allows knowledge of Allen's temporal relations over time elements, which may be both intervals and points. The objectives and characteristics of two major temporal attributes, i.e. ‘transaction time’ and ‘valid time’, are described. A graphical representation for the temporal network is presented, and inference over the network may be made by means of a consistency checker in terms of the graphical representation. An illustrative example of the system as applied to process control and management is provided.     

Bridging the gap between the Kodak and the Flickr generations: A novel interaction technique for collocated photo sharing

Passing around stacks of paper photographs while sitting around a table is one of the key social practices defining what is commonly referred to as the ‘Kodak Generation’. Due to the way digital photographs are stored and handled, this practice does not translate well to the ‘Flickr Generation’, where collocated photo sharing often involves the (wireless) transmission of a photo from one mobile device to another. In order to facilitate ‘cross-generation’ sharing without enforcing either practice, it is desirable to bridge this gap in a way that incorporates familiar aspects of both.In this paper, we discuss a novel interaction technique that addresses some of the constraints introduced by current communication technology, and that enables photo sharing in a way, which resembles the passing of stacks of paper photographs. This technique is based on dynamically generated spatial regions around mobile devices and has been evaluated through two user studies. The results we obtained indicate that our technique is easy to learn and as fast, or faster than, current technology such as transmitting photos between devices using Bluetooth. In addition, we found evidence of different sharing techniques influencing social practice around photo sharing. The use of our technique resulted in a more inclusive and group-oriented behavior in contrast to Bluetooth photo sharing, which resulted in a more fractured setting composed of sub-groups.     

Implementation of Biometric Systems — Security and Privacy Considerations

As biometric systems are deployed within security systems, or as part of identification programs, implementation issues relating to security and privacy need to be considered. The role of a biometric system is to recognize (or not) an individual through specific physiological or behavioral traits. The use of the word ‘recognize’ is significant — defined in the Oxford Dictionary as “identify as already known”. In other words, a biometric system does not establish the identity of an individual in any way, it merely recognizes that they are who they say they are (in a verification or a ‘positive identification’ system), or that they were not previously known to the system (in a ‘negative identification’ system, for example, to avoid double enrollment in a welfare system). This tie between the actual identity of an individual and the use of biometrics is subtle and provokes much debate, particularly relating to privacy and other societal issues. This paper seeks to clarify come of these issues by providing a framework, and by distinguishing between technology and societal issues.     

Robust control of a class of uncertain nonlinear systems

This paper considers the robust control of a class of nonlinear systems with real time-varying parameter uncertainty. Interest is focused on the design of linear dynamic output feedback control and two problems are addressed. The first one is the robust stabilization and the other is the problem of robust performance in an H_∞ sense. A technique is proposed for designing stabilizing controllers for both problems by converting them into ‘scaled’ H_∞ control problems which do not involve parameter uncertainty.