Reusable tools for user modelling

This paper refines the notion of reusability of tools for user modelling by defining three layers of reusable tools. It then reviews several research projects that have developed such reusable tools, GUMS, GUMAC, BGP-MS, um and UMT. Finally it summarises the current state of research into reusable tools in terms of these systems.This work is supported by Telecom (Australia) Grant Reference Y05/04/34 and BLO/02/02/89.     

Performance simulation tools

Understanding the performance of microprocessors, multiprocessors, and distributed computers requires studying them in isolation as well as observing their interaction with the entire system architecture     

Advanced tools for data conversion and database cost modelling

We consider two topics important to the database administrator: data conversion and database cost modelling. Suitable tools for these topics have been missing or their capabilities are insufficient in many practical situations today. We discuss approaches, principles, concepts and techniques, that can be used to manage these complex issues and pay special attention to factors that can be used to improve software which, in turn, provides the database administrator with a convenient and flexible interface.     

Supply network modelling and simulation methodology

Supply network management in today’s business climate characterized by high uncertainty, globalization of business, outsourcing, shorter product life-cycles, and high customer expectations is extremely challenging. Simulation can be a valuable tool for supply network analysis, planning, optimization, evaluation, and risk management. This paper presents a methodology for modelling both structure and dynamics of complex supply networks based on process approach. It also describes the model-driven simulation methodology and the main components of the simulation software solution: model database, process library, knowledge base, and execution engine. Finally, simulation results of the case supply network are presented.     

Efficient 6DOF tools for free-form surface modelling

In this paper we introduce a virtual integrated surface modeller (VISM) equipped with two advanced tools for 3D surface modelling in virtual reality (VR). VISM has been implemented thinking that the immediate visual feedback greatly improve complex surface modelling and also creativity. The proposed new tools are progressive skinning (PS) and curve-over-surface shaping (COSS), both implemented on a bimanual virtual environment. PS lets the designer generate a new surface by interactively and automatically adding section curves to a non-uniform rational B-spline surface. COSS is based on curve-over-a-surface progressive constraining in order to deform an area of an existent surface. Efficient numerical solutions are proposed to achieve true interactive modelling sessions.     

Graphical simulation environments for modelling and simulation of integrative physiology

Guyton’s original integrative physiology model was a milestone in integrative physiology, combining significant physiological knowledge with an engineering perspective to develop a computational diagrammatic model. It is still used in research and teaching, with a small number of variants on the model also in circulation. However, though new research has added significantly to the knowledge represented by Guyton’s model, and significant advances have been made in computing and simulation software, an accepted common platform to integrate this new knowledge has not emerged. This paper discusses the issues in the selection of a suitable platform, together with a number of current possibilities, and suggests a graphical computing environment for modelling and simulation. By way of example, a validated version of Guyton’s 1992 model, implemented in the ubiquitous Simulink environment, is presented which provides a hierarchical representation amenable to extension and suitable for teaching and research uses. It is designed to appeal to the biomedical engineer and physiologist alike.     

Behavioural equivalence in simulation modelling

Discrete event simulation has grown up as a practical technique for estimating the quantitative behaviour of systems, where direct measurement is undesirable or impractical. It is also used to understand the detailed functional behaviour of such systems. Its theory is largely that of experimental science, centering on statistical approaches to validation, rather than on the verification of detailed behaviour. On the other hand, much work has been done on understanding and proving functional properties of systems, using techniques of formal specification and concurrency modelling. This article presents an approach to understanding equivalence of behaviour of discrete event simulation models, using a technique from the concurrency world, Milner’s Calculus of Communicating Systems (CCS). This yields a significant advance over the main previous work, Schruben and Yücesan’s simulation graphs. CCS allows for the use of observational equivalence, which can capture a more flexible, behavioural notion of equivalence than the structural equivalence defined there.A common framework based on the process view of models is constructed, using a hierarchical graphical modelling language (Extended Activity Diagrams). This language is shown to map onto both the major constructs of the DEMOS discrete event simulation language and the corresponding CCS models. A graphically driven tool based on such a framework is presented, which generates both types of models. Using the CCS model, behavioural equivalences and differences in simulation models are demonstrated.     

Enhancing simulation efficiency with analytical tools

Some means of combining both computer simulation and analytical techniques are described to mutually enhance their efficiency as design tools and to motivate those involved in engineering design. To consider using such combinations in the included example, the parameter plane stability analysis technique is described briefly and extended beyond that reported in the literature. To increase its utility (through a simple set of recursive formulas) and its applicability (through the portrayal of the effect of varying the sampling period of the computer), the numerical values that were rapidly selected by analysis were needed. This obviated the need for “cut-and-try” methods to choose the numerical values, thereby saving both time and computer utilization.     

Cellular processing tools for high-performance simulation

Cellular automata offer a powerful modeling approach for complex systems in which global behavior arises from the collective effect of many locally interacting, simple components. Several tools based on CA are providing meaningful results for real-world applications. Cellular automata represent an efficient paradigm for the computer solution of important problems in science and engineering. Moreover, the CA model lets researchers effectively use parallel computers to achieve scalable performance. As researchers use parallel computers to solve scientific problems, they will need problem representations (paradigms) for this class of computers. Abstract mathematical models that offer an implicitly parallel representation of problems better match those architectures, but could benefit from new high-level languages, environments, and techniques. The three should support all the development steps of computational science applications while hiding architectural details from users. Computational science is also an interdisciplinary field in which many areas converge, and developing applications in this field requires the cooperation of people from different domains. Modeling and simulation using parallel cellular methods helps researchers cooperate by offering both a way to code an algorithm and an integrated environment for developing software     

A system for compartmental modelling and simulation

The paper describes a software package for modelling and simulating compartmental systems based upon a generalisation of the equations of compartmental systems. The aim is a versatile package which can be used for rapid model development. Its use is first illustrated in a number of simple classical examples. The power of the software--and more generally the methodology--is demonstrated by showing its application in developing a model-based system for insulin planning for diabetic patients. The software has been written in Pascal and runs on IBM PC and compatible computers.     

A review of Web-based simulation and supporting tools

The area of Web-based simulation (the integration of the Web with the field of simulation) (WBS) has grown since the mid-1990s. The Web itself has evolved rapidly, and current Web-related research areas include Web 2.0, service-oriented architectures and the Semantic Web. This paper gives a review of the area of WBS, exploring the advantages and disadvantages of WBS over classical simulation systems, a classification of different sub- and related-areas of WBS, an exploration of technologies that enable WBS, and the evolution of the Web in terms of its relationship to WBS.     

Spatial methane emission modelling from wetlands using geospatial tools

Wetland ecosystems have acquired importance among the scientific community because of their role in biogeochemical cycling and as source and sink of greenhouse gas emissions particularly methane (CH₄) in addition to the ecosystem services that they provide. To estimate the CH₄ emission from wetlands in spatial domain, models incorporating the geospatial tools are required. Accordingly, main focus of this study is to demonstrate the utility of geospatial techniques in assessing the spatial CH₄ emission variability from four different regions of Uttar Pradesh (UP), India, namely, Western, Central, Bundelkhand, and Eastern regions deploying Semi-Automated Empirical CH₄ emission Model (SEMEModel) using Moderate Resolution Imaging Spectro-radiometer data of 2010–2012. SEMEModel is a three-tier model which determines the CH₄ emissions in spatial domain as a function of remote sensing (RS) and Geographic Information System (GIS) derived wetland components including wetland area and corresponding temperature factors coupled with point CH₄ emission coefficients developed via field measurements. Results of the study have shown that eastern region of UP exhibited maximum estimated/modelled CH₄ emissions (43.10 Gg yr^?1) as compared to other regions due to more area being under wetlands whereas central region was found to be the least contributor (0.266 Gg yr^?1) due to the fact that it has minimum wetland area (0.40%) among all the regions. It was observed that estimated/modelled CH₄ emissions depicted an increase by 4.96 orders of magnitude in 2010–2011 and 4.04 orders of magnitude in 2011–2012 when estimated by applying literature-based global CH₄ emission coefficients for UP in place of CH₄ flux values derived in field. It signifies that the upscaling of CH₄ flux values using literature-based CH₄ flux values of one region to another region may not reflect actual values. Therefore, this study not only helps to improve accuracy of CH₄ emission estimates from wetlands but also credibly adjudges that integration of CH₄ flux field measurements with modern tools of RS and GIS will immensely assist to reduce the uncertainties in CH₄ emission predictions done over larger regions.     

Robot modelling — the tools needed for optimal design and utilization

There exists a recognized need to predict the actions of a robot or robot-type system. This paper investigates the requirements of the designers and users of such equipment and attempts to evaluate current work in this field. Much of the work being attempted is essentially novel and the aim is to minimize duplication and to concentrate effort in relevant areas.     

Object-oriented modelling and simulation for broadband network design

Various broadband networks have been planned and installed in recent years due to the increasing demand for new media applications and services. Since a nation-wide broadband network or national backbone as information superhighway requires an astronomical amount of investment, optimum design of the broadband network is very important. The design of the broadband network is very complicated and one has to consider network topology, resource capacities, routing schemes, and call admission control schemes as well as various traffic types.In this paper, an object-oriented (OO) approach is proposed for modelling and simulation of broadband networks for the purpose of analysis and design. An OO model which represents object and behaviour is presented with the broadband bursty traffics being modeled at the burst and call levels. The proposed OO modelling approach is applied to a backbone network design problem in Korea for demonstrating its validity and usefulness.     

Fuzzy modelling and simulation for aggregate production planning

The market demands and financial constraints in medium- to long-term production planning are often subject to uncertainties. As an extension of the author's previous paper, this paper focuses on a formulation and simulation analysis for multi-product aggregate production-planning problems with fuzzy demands and fuzzy capacities. The fuzzy production–inventory balance equation is formulated as a soft equation and can be interpreted as the possibility level of meeting the market demands, which is more meaningful and accepted by the practitioner than the previous one. With this interpretation, a fuzzy multi-product aggregate production-planning model is transformed into a parametric programming model. A simulation of a practical instance is conducted to illustrate the model and demonstrate the performance and effect of various parameters on the optimal aggregate production plan. The proposed formulation and simulation analysis can help the decision-maker make a reasonable and preferred aggregate plan to guarantee feasibility of the downstream family disaggregation plans.     

Qualitative modelling and simulation by piecewise linear analysis

Since applications of expert systems were typical in domains with no well defined models, qualitative methods for modelling and reasoning were soon developed. Most current qualitative reasoning programs derive the qualitative behaviour of a system by simulating a hand-crafted qualitative version of the differential equation that caracterizes the model of a system. This paper describes a method to construct a family of piecewise linear dynamical systems from the qualitative information contained in a model. We apply the dynamical system theory to deduce results about the behaviour of the family of dynamical systems constructed as a consequence of the qualitative model.