44 research outputs found
A generic approach, employing information systems, for introducing manufacturing information systems in SME 's
This thesis presents an approach which the small and medium size firms can use in-house
to introduce manufacturing information systems. The approach developed is
generic and employs information system design and analysis techniques to guide
Small and Medium size Enterprises (SME's) from specification of their need, right
through to the implementation of an appropriate solution. Although there are
various tools and methodologies that are available for large organisations needs,
none are available for SME's. Therefore, the approach presented in this thesis
provides original and significant improvements on current practice.
The approach emphasises the importance of taking a company wide approach to
analyse systems throughout its various departments to establish bad practices and
system flaws which may impinge on the performance of the manufacturing
operations.
The research involved three independent stages. The first stage was the
identification of the problem which was realised from two sources: literature survey
and interviews with case study company managers. The second stage was the
development of a novel approach. The final stage included the validation of the
approach by implementing it in five different SMEs in the Devon and Cornwall
region.
Through the use of this work, company's are encouraged to improve ownership and
commitment to the manufacturing information systems by fully involving the
relevant company personnel in identifying and resolving various problems. The
approach proposed also helps managers understand how the various processes work
in other areas of company, and can subsequently lead to improvements in other
departments
Novel analysis and modelling methodologies applied to pultrusion and other processes
Often a manufacturing process may be a bottleneck or critical to a business. This thesis
focuses on the analysis and modelling of such processest, to both better understand them,
and to support the enhancement of quality or output capability of the process.
The main thrusts of this thesis therefore are:
To model inter-process physics, inter-relationships, and complex processes in a
manner that enables re-exploitation, re-interpretation and reuse of this knowledge and
generic elements e.g. using Object Oriented (00) & Qualitative Modelling (QM)
techniques. This involves the development of superior process models to capture
process complexity and reuse any generic elements; To demonstrate advanced modelling and simulation techniques (e.g. Artificial Neural
Networks(ANN), Rule-Based-Systems (RBS), and statistical modelling) on a number
of complex manufacturing case studies; To gain a better understanding of the physics and process inter-relationships exhibited
in a number of complex manufacturing processes (e.g. pultrusion, bioprocess, and
logistics) using analysis and modelling.
To these ends, both a novel Object Oriented Qualitative (Problem) Analysis (OOQA)
methodology, and a novel Artificial Neural Network Process Modelling (ANNPM)
methodology were developed and applied to a number of complex manufacturing case
studies- thermoset and thermoplastic pultrusion, bioprocess reactor, and a logistics
supply chain. It has been shown that these methodologies and the models developed support
capture of complex process inter-relationships, enable reuse of generic elements,
support effective variable selection for ANN models, and perform well as a predictor of
process properties. In particular the ANN pultrusion models, using laboratory data from
IKV, Aachen and Pera, Melton Mowbray, predicted product properties very well
A generic model for representing software development methods.
This thesis has adopted the premise that the use of a method offers a valuable contribution to the software development process. Many methods have not been adequately defined. This thesis is based on the hypothesis that it is possible to represent software development methods using a Generic Method Representation (GMR). This GMR includes the three basic components of the method, which are the product model, the process model and the heuristic model. The elements and interrelationships of these models are investigated. In addition to a graphical representation, a method specification language (MSL) is derived, to enhance the expressive and executable power of GMR. A three-stage knowledge acquisition model, known as IFV (inspection, fabrication and verification), is also introduced to elicit method semantics from the available acquisition media. Moreover, the key benefits of meta modelling, such as method comparison, fragment dissection, method evaluation and selection (or customisation) of a method, are highlighted. An application of GMR, that is the mapping to a practical metaCASE tool model, is also illustrated comprehensively to demonstrate the applicability of the approach
A formal technique for the logical design of organisational information systems.
SIGLEAvailable from British Library Document Supply Centre- DSC:D51992/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Knowledge based system development as an engineering process
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Knowledge Based System (KBS) development is a difficult and challenging task, in particular in knowledge intensive domains. The traditional view of knowledge engineering is one of mining experts' knowledge and somehow transforming it into a machine usable form. This process, in general, suffers from insufficient or misconstrued representation of experts' problem solving behaviour. It is also unstructured and unduly biased at an early stage by design and implementation issues - normally in the form of incremental prototyping.
We believe that both knowledge acquisition and KBS development for real life applications will require a 'structured' approach. This approach should harness a KBS developer's ability in extracting knowledge and developing systems. The structure should also be sufficiently flexible to allow the knowledge engineer to use his sense of creativity in developing a KBS. This thesis puts forward such a structured approach, in which KBS development is carried out in an engineering fashion. A process in which the worker is provided with an environment for developing knowledge based systems as an engineering process, as opposed to that of an artform or crafting.
The main emphasis of this work is that part of the process which deals with the analysis and design phases in developing KBS. The analysis is performed at an 'epistemological' level, not coloured by design or implementation issues. The output of this phase captures both an expert's problem solving capability, and the business constraints placed upon the intended system. This is then used by the design process in order to create an optimal, workable, and elegant design architecture for the ultimate system.Commission for the European Communities'
ESPRIT programme (Project Number 1098
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Analogical specification reuse during requirements analysis
This thesis investigates analogy as a paradigm for retrieving, understanding and customising reusable specifications during requirements engineering. Cooperation between software engineers and support tools is necessary for effective analogical reuse. Retrieval uses a computational implementation of analogical reasoning to search and match many reusable specifications. On the other hand understanding, transferring and adapting specifications requires cooperation between the tool and software engineer. Cooperative support was designed for less-experienced software engineers with most to gain from successful specification reuse. Deliverables from this research have implications for software engineering, artificial intelligence, cognitive science and human-computer interaction. Specification retrieval is founded on a framework of software engineering analogies. This framework includes a set of domain abstractions describing key facts about software engineering domains. A computational model of analogical reasoning which matches domain descriptions to these abstractions was designed, implemented and evaluated during user studies with a prototype reuse advisor. An intelligent dialogue acts as a front-end to this retrieval mechanism by acquiring key domain facts prior to retrieving domain abstractions. This dialogue was designed from empirical studies of software engineering behaviour during requirements capture and modelling. Design of support tools for specification understanding and transfer was based on cognitive task and reasoning models of software engineering behaviour during analogical reuse and mental models of analogical understanding. Two empirical studies of inexperienced software engineers identified problematic mental laziness manifest as specification copying. A third study of expert software engineers who successfully reused specifications identified strategies for effective reuse. Detailed findings from all three studies informed the design of tool-based support for specification understanding and transfer. Findings also have implications for the design of tools to support other requirements engineering activities
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Mathematical modelling of gas flow networks in pellet induratlon systems
The objective of this research is to develop a simulation software tool, GASFLO, which should evaluate pressure, flow and temperature distributions of process gas in pellet induration system networks. Pellet induration systems are complex industrial systems composed of heterogenous components. The magnitude of gas through leaks i.e. the air entering or leaving the system from the points other than the known exits, is substantial and it adversely effects the performance of induration process. These leaks are very difficult to measure because of the hostile environment in the plant. The modelling of such industrial systems requires a notable amount of experimentation so the tool has been designed to enable the user modeller to change the component models and solution algorithms easily.
The conventional methods for flow network simulation are based on process centred approach, mostly composed of homogeneous components. For ease of computation, the non-pipe elements are modelled with an approximate linear or non-linear generic equation, whose coefficients can simulate different states of the element. The resulting set of non-linear equations is linearised and solved simultaneously using some iterative method. By contrast, GASFLO is based on device centred or unit based approach, and uses a two level hierarchical solution algorithm. The pellet induration system network is first idealised into a connected graph of streams (sets of serially connected components) and nodes. At the top or coordination level the flow and pressure distributions satisfying the Kirchhoff's laws are evaluated for the connected graph. At the lower or component level the exact mathematical models of components ale computed, in order of their occurrence in respective streams, using coordination variables as parameters. The converged flows are used for the temperature computation. The solution algorithm requires partitioning of the connected graph into forest and coforest structures, for which secondary algorithms have been developed using specific heuristics relevant to the pellet induration systems. The rigorous application of software engineering techniques for the design and implementation of software, enabled the resolution of the complexity of the modelled system, embedded the characteristics of 'quality software' into the resulting code and benefits from object orientation, even though it is implemented in standard FORTRAN 77.
GASFLO predicted results are in a good agreement with the measured results, it has been validated for a real life pellet induration system. It has been applied to simulate several practical scenarios, like addition of extra wind boxes to the zones and to determine how the plant production can be increased by certain ratio, such simulations were not feasible otherwise. GASFLO takes less than a minute to simulate a real-life pellet induration system on a 486 PC. The combined simulation with an other software tool, INDSYS, which evaluates the heat distribution in the solids, is also feasible
A Formal Methodology for the Specification of Distributed Systems From an Object Perspective.
Distributed computing systems are systems in which multiple processors run independently by communicating with each other. The design of distributed systems is difficult to achieve as the execution patterns of distributed system are typically more complex than those of non-distributed computing systems. The application of object-oriented techniques to the design of distributed systems has the potential to increase the power of modeling and computing. A formal methodology which includes a specification language, developed from an object perspective, for the development of distributed systems is presented. The formal specification language, DOSL (Distributed Object-based Specification Language), represents the specification of distributed systems from an object perspective. DOSL has a hybrid format which combines the property-oriented approach and the model-oriented approach. In particular, it has strong features for message passing specification. The semantics of DOSL is defined formally by two operational semantics methods: transition systems and Petri nets. In addition, a formal object-based methodology for the specification of distributed systems is given. The methodology presents a framework for using the DOSL specification language and includes an integrated formalized method for identification of objects, their operations and behaviors from multiple modeling formats. The implementation of the methodology is supported by assistance with a knowledge base