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.     

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.     

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.     

Real time animation of dynamic processes

Animation and simulation processes are facilitated by the use of high level graphic languages. The results of these processes are not generally available in real time, developing of microfilm delaying the screening of the process until some time after the computer run.A technique is described which overcomes this problem whilst still allowing the use of a high level graphical language.The addition of a single feature to a ‘static’ graphical language has transformed it into a ‘dynamic’ graphical language allowing real time illustration of time varying processes.The technique is not restricted to the language described but may well be employed by other high level graphical languages.     

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.     

Outsourcing strategy in two-stage call centers

This paper considers ‘two-stage’ call centers where some incoming calls are completed by first service while others require an additional second service. Although this type of call center is not uncommon, it has not been dealt with, if any, in the call center literature. In this paper, we introduce the concept of the ‘two-stage’ call center and discuss its features. Furthermore, we develop an effective outsourcing strategy in ‘two-stage’ call centers. To this end, we model ‘two-stage’ service system and propose several call routing structures. The structures are compared through numerical test and conventional queueing theories form the theoretical basis of our study.     

An ethnographic, action-based approach to human experience in virtual environments

This paper addresses a sensitive issue, of presence experienced by people interacting with a virtual environment (VE). Understanding ‘presence’, both theoretically and empirically, is important for designers interested in building effective computer-mediated environments for learning and work activities. The concept of presence has been treated mostly as a state of mind, to be investigated through ‘objective’ and ‘subjective’ measurement devices. The authors propose to add a different approach, which can address presence as an action-based process. This approach considers presence as the ongoing result of the actions performed in an environment and the local and cultural resources deployed by actors. In this sense, ‘presence’ can be captured by monitoring the sequence of participants’ actions and the aspects of the environment that are involved in this process; discourse/interaction analysis represents a fitting method for this goal. Sequences of interaction with a virtual library are used to illustrate some core aspects of an ethnographic, action-based approach to presence, such as the action possibilities envisaged by participants, the configuration of the virtual objects, the norms that regulate the interaction, the resources that are imported in the VE. These aspects are a necessary step to understand users’ presence in the VE and to plan consequent interventions to ameliorate the design of the interface.     

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].     

‘Light’ and ‘heavy’ work in the housekeeping service of a hospital

Work is organized based in part on the perceptions, by managers and workers, of workers, their abilities and the characteristics of the work to be done. Physical tasks in factories and services have often been divided into ‘light’ and ‘heavy’, a division that often corresponds formally or informally to gender. We have observed the work of cleaners on wards and in offices in an acute-care hospital, using several indicators of workload to identify and characterize typical work situations. ‘Heavy’ work was characterized by neutral postures, walking, repetitive movements involving the articulations of the upper limb pushing a 1-6 kg (wet or dry) mop, with occasional more intense effort. ‘Light’ work was characterized by flexed postures, walking, rapid repetitive movements involving the articulations of the upper limb and light weights (dusting) or 1-3 kg weights (emptying wastebaskets), with more occasional intense effort. We did not discover any compelling reason to divide cleaning into ‘light’ and ‘heavy’ work. Task assignment by sex may appear to be a solution to excessive job demands which would be better addressed by job re-design.     

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.     

An innovative software architecture to improve information flow from CAM to CNC

Over the years, machine tool evolution has allowed faster equipment, using new configurations, to manufacture parts that were almost impossible to machine in the past. Despite this tremendous evolution in machine and control technologies, the metalworking industry is still using the old ISO 6983 G-Codes programming interface to control the motion of these machines. This programming interface is not the most flexible or most appropriate for use by new open-architecture machine controllers and object-oriented high-level machining interfaces such as ISO 14649 (STEP-NC). This work proposes an innovative language, the ‘Base Numerical Control Language (BNCL),’ which is based on a low-level simple instruction set-like approach. The architecture is designed around two concepts: the BNCL virtual machine, which acts as a virtual microprocessor, and the BNCL virtual hardware, which is an abstraction of the machine tool. The language is characterised by its simplicity and flexibility, two qualities that are critical in a market in which the capabilities and performance of machines are constantly improving. The proposed architectural concepts are validated through various computer simulation and physical tests, including performance throughput, trajectory driving, and CNC controller extension capabilities.     

A linear-complexity reparameterisation strategy for the hierarchical bootstrapping of capabilities within perception–action architectures

Perception–action (PA) architectures are capable of solving a number of problems associated with artificial cognition, in particular, difficulties concerned with framing and symbol grounding. Existing PA algorithms tend to be ‘horizontal’ in the sense that learners maintain their prior percept–motor competences unchanged throughout learning. We here present a methodology for simultaneous ‘horizontal’ and ‘vertical’ perception–action learning in which there additionally exists the capability for incremental accumulation of novel percept–motor competences in a hierarchical fashion.The proposed learning mechanism commences with a set of primitive ‘innate’ capabilities and progressively modifies itself via recursive generalising of parametric spaces within the linked perceptual and motor domains so as to represent environmental affordances in maximally-compact manner. Efficient reparameterising of the percept domain is here accomplished by the exploratory elimination of dimensional redundancy and environmental context.Experimental results demonstrate that this approach exhibits an approximately linear increase in computational requirements when learning in a typical unconstrained environment, as compared with at least polynomially-increasing requirements for a classical perception–action system.     

Browsing a document collection represented in two- and three-dimensional virtual information space

This paper reports a study of information retrieval performance using an interface in which documents were represented by objects in a virtual environment. Spatial location was determined by semantic content, with inter-object distance representing semantic similarity of documents. The quality of spatial-semantic mapping was manipulated as was the number of dimensions (two versus three) in which document nodes were arranged. Participants were required to browse the information space and identify all documents relevant to a specified topic. Results indicated that participants were able to use three-dimensional spatial mapping of semantic information to facilitate task performance, with performance being better when the quality of the mapping was higher. Strategy differences were identified, with participants adopting a more ‘exhaustive’ approach when searching two-dimensional node arrangements, and a more ‘focused’ approach for three-dimensional arrangements. Cognitive ability was not strongly associated with task performance, but participants of relatively lower cognitive ability tended to out-perform those of higher cognitive ability in three-dimensional conditions. Possible reasons for these findings are discussed.     

Multi-console intelligent satellite graphics

The Department of the Army has undertaken the development of a graphics design system in order to satisfy a variety of engineering requirements. The system is being developed under the overall project, entitled: “Multidisciplined Engineering Design Evaluation and Analysis (MEDEA).” Goals inherent to the developing system are: hardware independence for local processors and graphic consoles, network orientation for resource sharing: multi-user independent operation and reasonable reaction to satisfy attention requests.The approach taken to realize these goals is one that provides a multi-program, multi-task environment. The environment is provided by an interrupt driven Multi-task Operating System (MTOS) that operates on a priority scheme to govern program execution and resource allocation. The priority system is dynamic in nature and governed by ‘static’, ‘relative’, and ‘time’ factors.Graphic processing is supported at the terminal. Large scale computations are supported remotely at large mainframes. Communications between the terminal and the remote mainframe are managed by a MEDEA Interface program resident at the remote site. The MEDEA interface resolves the peculiarities of the host system and allows the terminal graphic applications to view remote mainframe computational resources in a standard fashion.The hardware comprising the MEDEA design terminal is centered around an intelligent satellite terminal Ipporting a cluster of non-homogeneous graphic consoles. Test bed for the MEDEA design terminal has been implemented and will be used to debug and tune the MTOS system. define the minimum hardware configuration and provide a realistic production environment during system development.     

Flooding and Drying in Discontinuous Galerkin Finite-Element Discretizations of Shallow-Water Equations. Part 1: One Dimension

Free boundaries in shallow-water equations demarcate the time-dependent water line between ‘‘flooded’’ and ‘‘dry’’ regions. We present a novel numerical algorithm to treat flooding and drying in a formally second-order explicit space discontinuous Galerkin finite-element discretization of the one-dimensional or symmetric shallow-water equations. The algorithm uses fixed Eulerian flooded elements and a mixed Eulerian–Lagrangian element at each free boundary. When the time step is suitably restricted, we show that the mean water depth is positive. This time-step restriction is based on an analysis of the discretized continuity equation while using the HLLC flux. The algorithm and its implementation are tested in comparison with a large and relevant suite of known exact solutions. The essence of the flooding and drying algorithm pivots around the analysis of a continuity equation with a fluid velocity and a pseudodensity (in the shallow water case the depth). It therefore also applies, for example, to space discontinuous Galerkin finite-element discretizations of the compressible Euler equations in which vacuum regions emerge, in analogy of the above dry regions. We believe that the approach presented can be extended to finite-volume discretizations with similar mean level and slope reconstruction.This revised version was published online in July 2005 with corrected volume and issue numbers.     

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 influence of self-esteem and locus of control on perceived email-related stress

Electronic mail has become an indispensable tool in business and academia, and personal use is increasing every day. However, there is also evidence that Email, unlike more traditional communication media, can exert a powerful hold over its users and that many computer users experience stress as a direct result of email-related pressure. This paper develops a three-fold typology of orientations to email: ‘relaxed’, ‘driven’ and ‘stressed’. It further investigates whether the personality traits of self-esteem and locus of control are associated with email-related stress. It finds that low self-esteem is associated with the ‘driven’ orientation. It further suggests that the ‘stressed’ orientation may be related to how distractive email is perceived to be, compared with other forms of communication.     

Synchrony vs Asynchrony in Communication Primitives

We study, from the expressiveness point of view, the impact of synchrony in the communication primitives that arise when combining together some common and useful programming features like arity of data, communication medium and possibility of pattern matching. For some primitives, we show how their synchronous version can be encoded in their asynchronous counterpart via a fully abstract encoding, thus proving that the two versions have the same expressive power. For the remaining primitives, we prove that no ‘reasonable’ encoding can exist, thus proving that synchrony adds expressiveness to the language.     

A vapor extraction teaching module based on AIRFLOW/SVE

This is the fourth in a series of papers exploring the application of professional quality software to environmental engineering education. Jennings (1997) discussed how the differences between ‘professional’ and ‘educational’ software should translate into software attributes and illustrated many of these attributes using the bioremediation package BIO1D (Srinivasan and Mercer, 1989). Jennings and Kuhlman (1997) illustrated more of these attributes using the MATHCAD 6.0 (Mathsoft, Inc., 1995) electronic book air pollution modeling package GAUSSIAN MODELS 1.1 (Zannetti, 1995). Most recently, Mesania and Jennings (1997) illustrated the power of a ‘pseudo-CAD’ user interface using the landfill hydraulic analysis program Help Model for Windows—HMfW v2.05 (Grace Dearborne, Inc., 1993). This paper concentrates on the power of using a true CAD user interface. This is done using the AIRFLOW/SVE (Guiguer et al., 1995) which evaluates vapor extraction soil remediation. Example simulations are presented to illustrate the power of CAD interfaces to express complex problems and to present results in easily comprehended graphics. Examples are also presented to illustrate how this package can help students identify successful applications of vapor extraction remediation.     

A universality advantage of stochastic excitation signals for adaptive control

Adaptive control schemes usually depend on estimation of system parameters, which in turn depends excitation of modes associated with these parameters. Such excitation is supplied by plant noise, the adaptive control signal itself, and any external excitation such as a reference signal. In this note, it is shown that there is a universality advantage for any externally applied signal to be stochastic rather than deterministic. The crucial property of a stochastic signal exploited in this note is its unpredictability by any causal system, such as an adaptive control scheme. When such unpredictable signals excite an adaptive control scheme, there is no need to deliberately constrain the adaptation to be ‘slow’ or ‘excitation maintaining’ to ensure adequate identification.