Computer integrated manufacturing (CIM) and the principle of business control

In response to the increasing international competitiveness, many manufacturing businesses are rethinking their management strategies and philosophies towards achieving a computer integrated environment. The explosive growth in Advanced Manufacturing Technology (AMI) has resulted in the formation of functional "Islands of Automation" such as Computer Aided Design (CAD), Computer Aided Manufacturing (CAM), Computer Aided Process Planning (CAPP) and Manufacturing Resources Planning (MRPII). This has resulted in an environment which has focussed areas of excellence and poor overall efficiency, co-ordination and control. The main role of Computer Integrated Manufacturing (CIM) is to integrate these islands of automation and develop a totally integrated and controlled environment. However, the various perceptions of CIM, although developing, remain focussed on a very narrow integration scope and have consequently resulted in mere linked islands of automation with little improvement in overall co-ordination and control. This thesis, that is the research described within, develops and examines a more holistic view of CIM, which is based on the integration of various business elements. One particular business element, namely control, has been shown to have a multi-facetted and underpinning relationship with the CIM philosophy. This relationship impacts various CIM system design aspects including the CIM business analysis and modelling technique, the specification of systems integration requirements, the CIM system architectural form and the degree of business redesign. The research findings show that fundamental changes to CIM system design are required; these are incorporated in a generic CIM design methodology. The affect and influence of this holistic view of CIM on a manufacturing business has been evaluated through various industrial case study applications. Based on the evidence obtained, it has been concluded that this holistic, control based approach to CIM can provide a greatly improved means of achieving a totally integrated and controlled business environment. This generic CIM methodology will therefore make a significant contribution to the planning, modelling, design and development of future CIM systems.

Aspects of the design and operation of production control systems in manufacturing industry

Computerised production control developments have concentrated on Manufacturing Resources Planning (MRP II) systems. The literature suggests however, that despite the massive investment in hardware, software and management education, successful implementation of such systems in manufacturing industries has proved difficult. This thesis reviews the development of production planning and control systems, in particular, investigates the causes of failures in implementing MRP/MRP II systems in industrial environments and argues that the centralised and top-down planning structure, as well as the routine operational methodology of such systems, is inherently prone to failure. The thesis reviews the control benefits of cellular manufacturing systems but concludes that in more dynamic manufacturing environments, techniques such as Kanban are inappropriate. The basic shortcomings of MRP II systems are highlighted and a new enhanced operational methodology based on distributed planning and control principles is introduced. Distributed Manufacturing Resources Planning (DMRP), was developed as a capacity sensitive production planning and control solution for cellular manufacturing environments. The system utilises cell based, independently operated MRP II systems, integrated into a plant-wide control system through a Local Area Network. The potential benefits of adopting the system in industrial environments is discussed and the results of computer simulation experiments to compare the performance of the DMRP system against the conventional MRP II systems presented. DMRP methodology is shown to offer significant potential advantages which include ease of implementation, cost effectiveness, capacity sensitivity, shorter manufacturing lead times, lower working in progress levels and improved customer service.

Cost effectiveness of production control systems

This thesis deals with the problems associated with the planning and control of production, with particular reference to a small aluminium die casting company. The main problem areas were identified as: (a) A need to be able to forecast the customers demands upon the company's facilities. (b) A need to produce a manufacturing programme in which the output of the foundry (or die casting section) was balanced with the available capacity in the machine shop. (c) The need to ensure that the resultant system enabled the company's operating budget to have a reasonable chance of being achieved. At the commencement of the research work the major customers were members of the automobile industry and had their own system of forecasting, from which they issued manufacturing schedules to their component suppliers, The errors in the forecast were analysed and the distributions noted. Using these distributions the customer's forecast was capable of being modified to enable his final demand to be met with a known degree of confidence. Before a manufacturing programme could be developed the actual manufacturing system had to be reviewed and it was found that as with many small companies there was a remarkable lack of formal control and written data. Relevant data with regards to the component and the manufacturing process had therefore to be collected and analysed. The foundry process was fixed but the secondary machining operations were analysed by a technique similar to Component Flow Analysis and as a result the machines were arranged in a series of flow lines. A system of manual production control was proposed and for comparison, a local computer bureau was approached and a system proposed incorporating the production of additional management information. These systems are compared and the relative merits discussed and a proposal made for implementation.

A critical evaluation of contrast susceptibility as a predictor of driving accident involvement

Contrast susceptibility is defined as the difference in visual acuity recorded for high and low contrast optotypes. Other researchers refer to this parameter as "normalised low contrast acuity". Pilot surveys have revealed that contrast susceptibility deficits are more strongly related to driving accident involvement than are deficits in high contrast visual acuity. It has been hypothesised that driving situation avoidance is purely based upon high contrast visual acuity. Hence, the relationship between high contrast visual acuity and accidents is masked by situation avoidance whilst drivers with contrast susceptibility deficits remain prone to accidents in poor visibility conditions. A national survey carried out to test this hypothesis provided no support for either the link between contrast susceptibility deficits and accidents involvement or the proposed hypothesis. Further, systematically worse contrast susceptibility scores emerged from vision screeners compared to wall mounted test charts. This discrepancy was not due to variations in test luminance or instrument myopia. Instead, optical imperfections inherent in vision screeners were considered to be responsible. Although contrast susceptibility is unlikely to provide a useful means of screening drivers' vision, previous research does provide support for its ability to detect visual deficits that may influence everyday tasks. In this respect, individual contrast susceptibility variations were found to reflect variations in the contrast sensitivity function - a parameter that provides a global estimate of human contrast sensitivity.

The formation and impact of hazard control policy:a study of the regulation of white lead paint in Britain

Government regulation of industrial hazards is examined in the context of the economic and technical processes of industrial development. Technical problems and costs of control are considered as factors in both the formation and impact of regulation. This thesis focuses on an historical case-study of the regulation of the hazard to painting workers from the use of lead pigments in paint. A regulatory strategy based on the prohibition of lead paints gained initial acceptance within the British state in 1911, but was subsequently rejected in favour of a strategy that allowed continued use of lead paint subject to hygiene precautions. The development of paint technology and its determinants, including concern about health hazards, are analysed, focusing on the innovation and diffusion into the paint industry of the major white pigments: white lead (PbC03 .PB(OH)2)and its substitutes. The process of regulatory development is examined, and the protracted and polarised regulatory d~bate contrasted to the prevailing 'consensual' methods of workplace regulation. The rejection of prohibition is analysed in terms of the different political and technical resources of those groups in conflict over this policy. This highlights the problems of consensus formation around such a strategy, and demonstrates certain constraints on state regulatory activity, particularly regarding industrial development. Member-states of the International Labour Organisation agreed to introduce partial prohibition of lead paint in 1921. Whether this was implemented is related to the economic importance of lead and non-lead metal and pigment industries to a nation. An analysis is made of the control of lead poisoning. The rate of control is related to the economic and technological trajectory of the regulated industry. Technical and organisational characteristics are considered as well as regulatory factors which range from voluntary compliance and informal pressures to direct legal requirements. The implications of this case-study for the analysis of the development and impacts of regulation are assessed.

Loss of Akt activity increases circulating soluble endoglin release in preeclampsia:identification of inter-dependency between Akt-1 and heme oxygenase-1

Aims - Endothelial dysfunction is a hallmark of preeclampsia. Desensitization of the phosphoinositide 3-kinase (PI3K)/Akt pathway underlies endothelial dysfunction and haeme oxygenase-1 (HO-1) is decreased in preeclampsia. To identify therapeutic targets, we sought to assess whether these two regulators act to suppress soluble endoglin (sEng), an antagonist of transforming growth factor-ß (TGF-ß) signalling, which is known to be elevated in preeclampsia. Methods and results - Vascular endothelial growth factor-A (VEGF-A), fibroblast growth factor (FGF-2), angiopoietin-1 (Ang-1), and insulin, which all activate the PI3K/Akt pathway, inhibited the release of sEng from endothelial cells. Inhibition of the PI3K/Akt pathway, by overexpression of phosphatase and tensin homolog (PTEN) or a dominant-negative isoform of Akt (Aktdn) induced sEng release from endothelial cells and prevented the inhibitory effect of VEGF-A. Conversely, overexpression of a constitutively active Akt (Aktmyr) inhibited PTEN and cytokine-induced sEng release. Systemic delivery of Aktmyr to mice significantly reduced circulating sEng, whereas Aktdn promoted sEng release. Phosphorylation of Akt was reduced in preeclamptic placenta and this correlated with the elevated level of circulating sEng. Knock-down of Akt using siRNA prevented HO-1-mediated inhibition of sEng release and reduced HO-1 expression. Furthermore, HO-1 null mice have reduced phosphorylated Akt in their organs and overexpression of Aktmyr failed to suppress the elevated levels of sEng detected in HO-1 null mice, indicating that HO-1 is required for the Akt-mediated inhibition of sEng. Conclusion - The loss of PI3K/Akt and/or HO-1 activity promotes sEng release and positive manipulation of these pathways offers a strategy to circumvent endothelial dysfunction.

New measures of job control, cognitive demand and production responsibility

Recent research has highlighted several job characteristics salient to employee well-being and behavior for which there are no adequate generally applicable measures. These include timing and method control, monitoring and problem-solving demand, and production responsibility. In this article, an attempt to develop measures of these constructs provided encouraging results. Confirmatory factor analyses applied to data from 2 samples of shop-floor employees showed a consistent fit to a common 5-factor measurement model. Scales corresponding to each of the dimensions showed satisfactory internal and test–retest reliabilities. As expected, the scales also discriminated between employees in different jobs and employees working with contrasting technologies.

Value of glycaemic control in diabetes

Full text: Several Lancet publications have questioned the value of glycaemic control in diabetic patients. For example, in their Comment (Sept 29, p 1103),1 John Cleland and Stephen Atkin state that “Improved glycaemic control is not a surrogate for effective care of patients who have diabetes”, and Victor Montori and colleagues (p 1104)2 claim that “HbA1c loses its validity as a surrogate marker when patients have a constellation of metabolic abnormalities”. We are concerned that the reaction against “glucocentricity” in the field of diabetes has gone too far. Even the UK's National Prescribing Centre website, carrying the National Health Service logo, includes comments that undermine the value of glycaemic control. For example, referring to the United Kingdom Prospective Diabetes Study (UKPDS), this site states that “Compared with ‘conventional control��� there was no benefit from tight control of blood glucose with sulphonylureas or insulin with regard to total mortality, diabetes-related death, macrovascular outcomes or microvascular outcomes, including all the most serious ones such as blindness or kidney failure”.3 It is well established that better glycaemic control reduces long-term microvascular complications in type 1 and type 2 diabetes.4 In type 2 diabetes, the UKPDS reported that a composite microvascular endpoint (retinopathy requiring photocoagulation, vitreous haemorrhage, and fatal or non-fatal renal failure) was reduced by 25% in patients randomised to intensive glucose control (p=0·0099).4 To imply that these are not patient-relevant outcomes is to distort the evidence. Many studies have also found that improved glycaemic control reduces macrovascular complications.5 Do not be misled: glycaemic control remains a crucial component in the care of people with diabetes. The authors have received research support and undertaken ad hoc consultancies and speaker engagements for several pharmaceutical companies.

What checkers actually check:an eye tracking study of inhibitory control and working memory

Background - Not only is compulsive checking the most common symptom in Obsessive Compulsive Disorder (OCD) with an estimated prevalence of 50–80% in patients, but approximately ~15% of the general population reveal subclinical checking tendencies that impact negatively on their performance in daily activities. Therefore, it is critical to understand how checking affects attention and memory in clinical as well as subclinical checkers. Eye fixations are commonly used as indicators for the distribution of attention but research in OCD has revealed mixed results at best. Methodology/Principal Finding - Here we report atypical eye movement patterns in subclinical checkers during an ecologically valid working memory (WM) manipulation. Our key manipulation was to present an intermediate probe during the delay period of the memory task, explicitly asking for the location of a letter, which, however, had not been part of the encoding set (i.e., misleading participants). Using eye movement measures we now provide evidence that high checkers’ inhibitory impairments for misleading information results in them checking the contents of WM in an atypical manner. Checkers fixate more often and for longer when misleading information is presented than non-checkers. Specifically, checkers spend more time checking stimulus locations as well as locations that had actually been empty during encoding. Conclusions/Significance - We conclude that these atypical eye movement patterns directly reflect internal checking of memory contents and we discuss the implications of our findings for the interpretation of behavioural and neuropsychological data. In addition our results highlight the importance of ecologically valid methodology for revealing the impact of detrimental attention and memory checking on eye movement patterns.

Application of computer control to the production of synthetic resins

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