The design of a support department simulator for use in the design of manufacturing systems

Manufacturing firms are driven by competitive pressures to continually improve the effectiveness and efficiency of their organisations. For this reason, manufacturing engineers often implement changes to existing processes, or design new production facilities, with the expectation of making further gains in manufacturing system performance. This thesis relates to how the likely outcome of this type of decision should be predicted prior to its implementation. The thesis argues that since manufacturing systems must also interact with many other parts of an organisation, the expected performance improvements can often be significantly hampered by constraints that arise elsewhere in the business. As a result, decision-makers should attempt to predict just how well a proposed design will perform when these other factors, or 'support departments', are taken into consideration. However, the thesis also demonstrates that, in practice, where quantitative analysis is used to evaluate design decisions, the analysis model invariably ignores the potential impact of support functions on a system's overall performance. A more comprehensive modelling approach is therefore required. A study of how various business functions interact establishes that to properly represent the kind of delays that give rise to support department constraints, a model should actually portray the dynamic and stochastic behaviour of entities in both the manufacturing and non-manufacturing aspects of a business. This implies that computer simulation be used to model design decisions but current simulation software does not provide a sufficient range of functionality to enable the behaviour of all of these entities to be represented in this way. The main objective of the research has therefore been the development of a new simulator that will overcome limitations of existing software and so enable decision-makers to conduct a more holistic evaluation of design decisions. It is argued that the application of object-oriented techniques offers a potentially better way of fulfilling both the functional and ease-of-use issues relating to development of the new simulator. An object-oriented analysis and design of the system, called WBS/Office, are therefore presented that extends to modelling a firm's administrative and other support activities in the context of the manufacturing system design process. A particularly novel feature of the design is the ability for decision-makers to model how a firm's specific information and document processing requirements might hamper shop-floor performance. The simulator is primarily intended for modelling make-to-order batch manufacturing systems and the thesis presents example models created using a working version of WBS/Office that demonstrate the feasibility of using the system to analyse manufacturing system designs in this way.

Current practice and opinion in special schools for the maladjusted in England and Wales

This study seeks to describe current practice and opinion in schools for the maladjusted in England and Wales and to exarnlne how far this coincides with earlier descriptions. A review of the literature provides an account of this earlier work, and data accrued from questionnaires completed by 114 schools describe current practice and opinion. The study represents the most extensive empirical enquiry into the work of these schools since 1955 and provides a wide data basis for future research and assessment of progress and change. The data suggest that there is much communality of practice and opinion within the schools, with most schools emphasising their therapeutic rather than their educational purpose. The work is characterised by the wide use and perceived efficacy of warm, caring adult to child relationships, improvement of pupil self-image through success, and individual counselling and discussion, which permeate a structure of routine, discipline and educational concern. Specialised treatments are not used widely and involve only a minority of pupils. Practice tends to be in reference to conduct disordered pupils who are now perceived as the largest single disorder group within the schools, whereas previously neurotic disorders formed the largest single group. The majority of pupils are perceived as underachieving on entry and requiring remedial help: consequently the educational programme has a remedial bias. For staff, qualities of personality are considered to be more valuable than professional skills. The schools differ in the emphasis they allocate to one or more of four identified areas of treatment described as concern for pupils' needs; degree of pupil participation; theoretical orientation: and the use of external controls. There is a diminished reference to psychoanalytical theory and an increased reference to behaviourist theory relative to previous practice. Similarly, the use and perceived importance and effectiveness of pupil participation and unconditional affection has diminished.

A genetic algorithm to optimise the component placement process in the PCB assembly

In printed circuit board (PCB) assembly, the efficiency of the component placement process is dependent on two interrelated issues: the sequence of component placement, that is, the component sequencing problem, and the assignment of component types to feeders of the placement machine, that is, the feeder arrangement problem. In cases where some components with the same type are assigned to more than one feeder, the component retrieval problem should also be considered. Due to their inseparable relationship, a hybrid genetic algorithm is adopted to solve these three problems simultaneously for a type of PCB placement machines called the sequential pick-and-place (PAP) machine in this paper. The objective is to minimise the total distance travelled by the placement head for assembling all components on a PCB. Besides, the algorithm is compared with the methods proposed by other researchers in order to examine its effectiveness and efficiency.

Simulation based knowledge elicitation:effect of visual representation and model parameters

Since much knowledge is tacit, eliciting knowledge is a common bottleneck during the development of knowledge-based systems. Visual interactive simulation (VIS) has been proposed as a means for eliciting experts’ decision-making by getting them to interact with a visual simulation of the real system in which they work. In order to explore the effectiveness and efficiency of VIS based knowledge elicitation, an experiment has been carried out with decision-makers in a Ford Motor Company engine assembly plant. The model properties under investigation were the level of visual representation (2-dimensional, 2½-dimensional and 3-dimensional) and the model parameter settings (unadjusted and adjusted to represent more uncommon and extreme situations). The conclusion from the experiment is that using a 2-dimensional representation with adjusted parameter settings provides the better simulation-based means for eliciting knowledge, at least for the case modelled.

An Investigation of the Irish Road Haulage Industry’s External Environment

The movement of goods is of critical importance to an economy, especially one, which is dependent on international trade such as Ireland. Considering Irelands distribution of manufacturing and other organisations throughout the country, many firms are dependent upon road haulage effectiveness and efficiency. In recent times there has been somewhat of a growing unease in the road haulage industry in relation to increasing cost, squeezing profit margins even tighter. An understanding of the Irish road haulier’s business environment would undoubtedly shed greater light onto their situation. The paper addresses this issue with an analysis of the industry’s competitive environment. The first step of the research methodology was an intensive search for pertinent literature, from which a limited amount of information was obtained. A confined amount of primary research was then carried out. Purposive sampling was used to establish the required respondents. The techniques used were the research conversation approach in combination with semi-structured interviews. Following this a structured postal questionnaire was issued to obtain quantitative statistics. The preliminary results of which are outlined. The analysis identifies a number of issues within the Irish road haulage industry. The paper concludes with the findings that the Irish road haulage industry is at present a brutally competitive environment due to its fragmented nature and the power of its customers. It also identifies the need for further research in order to establish the validity of certain points and issues.

Attributed graph kernels using the Jensen-Tsallis q-differences

We propose a family of attributed graph kernels based on mutual information measures, i.e., the Jensen-Tsallis (JT) q-differences (for q  ∈ [1,2]) between probability distributions over the graphs. To this end, we first assign a probability to each vertex of the graph through a continuous-time quantum walk (CTQW). We then adopt the tree-index approach [1] to strengthen the original vertex labels, and we show how the CTQW can induce a probability distribution over these strengthened labels. We show that our JT kernel (for q  = 1) overcomes the shortcoming of discarding non-isomorphic substructures arising in the R-convolution kernels. Moreover, we prove that the proposed JT kernels generalize the Jensen-Shannon graph kernel [2] (for q = 1) and the classical subtree kernel [3] (for q = 2), respectively. Experimental evaluations demonstrate the effectiveness and efficiency of the JT kernels.

Quantum kernels for unattributed graphs using discrete-time quantum walks

In this paper, we develop a new family of graph kernels where the graph structure is probed by means of a discrete-time quantum walk. Given a pair of graphs, we let a quantum walk evolve on each graph and compute a density matrix with each walk. With the density matrices for the pair of graphs to hand, the kernel between the graphs is defined as the negative exponential of the quantum Jensen–Shannon divergence between their density matrices. In order to cope with large graph structures, we propose to construct a sparser version of the original graphs using the simplification method introduced in Qiu and Hancock (2007). To this end, we compute the minimum spanning tree over the commute time matrix of a graph. This spanning tree representation minimizes the number of edges of the original graph while preserving most of its structural information. The kernel between two graphs is then computed on their respective minimum spanning trees. We evaluate the performance of the proposed kernels on several standard graph datasets and we demonstrate their effectiveness and efficiency.

Carbon efficiency evaluation:an analytical framework using fuzzy DEA

Data Envelopment Analysis (DEA) is a powerful analytical technique for measuring the relative efficiency of alternatives based on their inputs and outputs. The alternatives can be in the form of countries who attempt to enhance their productivity and environmental efficiencies concurrently. However, when desirable outputs such as productivity increases, undesirable outputs increase as well (e.g. carbon emissions), thus making the performance evaluation questionable. In addition, traditional environmental efficiency has been typically measured by crisp input and output (desirable and undesirable). However, the input and output data, such as CO2 emissions, in real-world evaluation problems are often imprecise or ambiguous. This paper proposes a DEA-based framework where the input and output data are characterized by symmetrical and asymmetrical fuzzy numbers. The proposed method allows the environmental evaluation to be assessed at different levels of certainty. The validity of the proposed model has been tested and its usefulness is illustrated using two numerical examples. An application of energy efficiency among 23 European Union (EU) member countries is further presented to show the applicability and efficacy of the proposed approach under asymmetric fuzzy numbers.

Evaluation of research in efficiency and productivity:a survey and analysis of the first 30 years of scholarly literature in DEA

Since the original Data Envelopment Analysis (DEA) study by Charnes et al. [Measuring the efficiency of decision-making units. European Journal of Operational Research 1978;2(6):429–44], there has been rapid and continuous growth in the field. As a result, a considerable amount of published research has appeared, with a significant portion focused on DEA applications of efficiency and productivity in both public and private sector activities. While several bibliographic collections have been reported, a comprehensive listing and analysis of DEA research covering its first 30 years of history is not available. This paper thus presents an extensive, if not nearly complete, listing of DEA research covering theoretical developments as well as “real-world” applications from inception to the year 2007. A listing of the most utilized/relevant journals, a keyword analysis, and selected statistics are presented.

Assessing the effectiveness of business support services in England:evidence from a theory based evaluation

In England, publicly supported advice to small firms is organized primarily through the Business Link (BL) network. Using the programme theory underlying this business support, we develop four propositions and test these empirically using data from a new survey of over 3000 English SMEs. We find strong support for the value to BL operators of a high profile to boost take-up. We find support for the BL’s market segmentation that targets intensive assistance to younger firms and those with limited liability. Allowing for sample selection, we find no significant effects on growth from ‘other’ assistance but find a significant employment boost from intensive assistance. This partially supports the programme theory assertion that BL improves business growth and strongly supports the proposition that there are differential outcomes from intensive and other assistance. This suggests an improvement in the BL network, compared with earlier studies, notably Roper et al. (2001), Roper and Hart (2005).

Evaluation of DNA enzymes targeted against the RNA component of human telomerase

Glioblastoma Multiforme (GBM) is a highly malignant form of brain cancer for which there is currently no effective cure. Consequently, developing new therapies and elucidating effective targets is crucial for this fatal disease. In recent years, DNA enzymes, deoxyribonucleic acid molecules with enzymatic activity, have emerged. In the same manner as ribozymes, DNA enzymes are able to effect cleavage of RNA in a sequence-specific manner, and operate with catalytic efficiency. In this study, two DNA enzymes were designed to target the template region of human telomerase RNA (hTR), utilising the 10-23 and 8-17 catalytic motifs elucidated by Santoro and Joyce (1997). Telomerase is an RNA-dependent DNA polymerase, which stabilises telomere lengths by adding hexameric repeats (TTAGGG in humans) to chromosome termini, thus preventing the telomere shortening that usually occurs during mitotic cell division. Telomerase activity, whilst absent in normal somatic tissues, is present in almost 90% of all tumours. Thus, there is speculation that telomerase may be the much sought universal target for therapeutic intervention in cancer. In vitro cleavage assays showed both DNA enzymes to be catalytically competent. Unmodified phosphodiester (PO) backbone DNA enzymes were rapidly degraded in the presence of serum, with a half-life of 10 minutes. The common approach of introducing phosphorothioate (PS) linkages was used in an effort to overcome this instability. As a result of concurrent activity and stability studies on the DNA enzymes with various numbers of PS linkages, the DNA enzymes with a PO core and PS arms were chosen for use in further cell work. The cleavage activity of both was shown to be specific and affected by temperature, pH, MgCI2 concentration and enzyme concentration. Both DNA enzyme motifs reduced telomerase activity in cell lysates, as assessed by the telomerase repeat amplification protocol (TRAP) with an IC50 of 100nM. DNA enzymes being polyanionic molecules do not readily cross biological barriers. Cellular association of naked DNA enzyme was inefficient at less than 2%. Cellular delivery of the DNA enzymes was effectively improved using commercial cationic lipid formulations. However, the lipid-mediated delivery of DNA enzymes to U87-MG cells over a 4-hour period did not significantly inhibit cell proliferation compared to controls. This is possibly due to an expected lag period between the inhibition of telomere maintenance and cell death. Therefore, biodegradable polymer microspheres were investigated as a potential delivery option for prolonged and sustained delivery. In vitro release profiles showed that after an initial burst, sustained release of DNA enzymes was observed over 35 days. Finally, the efficacy and specificity of the DNA enzymes were demonstrated in a luciferase based reporter assay. Specific inhibition of luciferase expression was displayed at 10nM. Thus DNA enzymes have potential against endogenous cellular targets.

An evaluation of the effectiveness of intervention strategies for the promotion of health and safety performance in small firms

Recognition of the contribution of small firms to the UK economy has grown considerably since 1995 when this research first began. The poor record of small firms in managing health and safety effectively has caused concern, and efforts made to improve knowledge and awareness of the target group through various initiatives have had some success. This research thesis attempts to identify the range of intervention routes and methods available to reach the target group, and to consider ways of evaluating the outcome of such efforts. Various interventions were tested with small firms, including a Workshop; use of Questionnaires; short postal Reply Slip survey; leading to a closer evaluation of a specific industry- the Licensed Trade. Attitudes and beliefs of the sample were identified, and observations carried out to consider actions taken by workers and others in the workplace. These empirical research findings were used to develop the theme of Primary and Secondary interventions intended to change behaviours, and to confirm assumptions about what small firms currently do to manage health and safety risks. Guidance for small firms was developed as a Secondary intervention tool to support Primary interventions, such as inspection or insurance provision.

Rapid testing for group B streptococcus during labour: a test accuracy study with evaluation of acceptability and cost-effectiveness

OBJECTIVE: To determine the accuracy, acceptability and cost-effectiveness of polymerase chain reaction (PCR) and optical immunoassay (OIA) rapid tests for maternal group B streptococcal (GBS) colonisation at labour. DESIGN: A test accuracy study was used to determine the accuracy of rapid tests for GBS colonisation of women in labour. Acceptability of testing to participants was evaluated through a questionnaire administered after delivery, and acceptability to staff through focus groups. A decision-analytic model was constructed to assess the cost-effectiveness of various screening strategies. SETTING: Two large obstetric units in the UK. PARTICIPANTS: Women booked for delivery at the participating units other than those electing for a Caesarean delivery. INTERVENTIONS: Vaginal and rectal swabs were obtained at the onset of labour and the results of vaginal and rectal PCR and OIA (index) tests were compared with the reference standard of enriched culture of combined vaginal and rectal swabs. MAIN OUTCOME MEASURES: The accuracy of the index tests, the relative accuracies of tests on vaginal and rectal swabs and whether test accuracy varied according to the presence or absence of maternal risk factors. RESULTS: PCR was significantly more accurate than OIA for the detection of maternal GBS colonisation. Combined vaginal or rectal swab index tests were more sensitive than either test considered individually [combined swab sensitivity for PCR 84% (95% CI 79-88%); vaginal swab 58% (52-64%); rectal swab 71% (66-76%)]. The highest sensitivity for PCR came at the cost of lower specificity [combined specificity 87% (95% CI 85-89%); vaginal swab 92% (90-94%); rectal swab 92% (90-93%)]. The sensitivity and specificity of rapid tests varied according to the presence or absence of maternal risk factors, but not consistently. PCR results were determinants of neonatal GBS colonisation, but maternal risk factors were not. Overall levels of acceptability for rapid testing amongst participants were high. Vaginal swabs were more acceptable than rectal swabs. South Asian women were least likely to have participated in the study and were less happy with the sampling procedure and with the prospect of rapid testing as part of routine care. Midwives were generally positive towards rapid testing but had concerns that it might lead to overtreatment and unnecessary interference in births. Modelling analysis revealed that the most cost-effective strategy was to provide routine intravenous antibiotic prophylaxis (IAP) to all women without screening. Removing this strategy, which is unlikely to be acceptable to most women and midwives, resulted in screening, based on a culture test at 35-37 weeks' gestation, with the provision of antibiotics to all women who screened positive being most cost-effective, assuming that all women in premature labour would receive IAP. The results were sensitive to very small increases in costs and changes in other assumptions. Screening using a rapid test was not cost-effective based on its current sensitivity, specificity and cost. CONCLUSIONS: Neither rapid test was sufficiently accurate to recommend it for routine use in clinical practice. IAP directed by screening with enriched culture at 35-37 weeks' gestation is likely to be the most acceptable cost-effective strategy, although it is premature to suggest the implementation of this strategy at present.