Using system dynamics in a discrete-event simulation study of a manufacturing plant

Purpose - To provide an example of the use of system dynamics within the context of a discrete-event simulation study. Design/methodology/approach - A discrete-event simulation study of a production-planning facility in a gas cylinder-manufacturing plant is presented. The case study evidence incorporates questionnaire responses from sales managers involved in the order-scheduling process. Findings - As the project progressed it became clear that, although the discrete-event simulation would meet the objectives of the study in a technical sense, the organizational problem of "delivery performance" would not be solved by the discrete-event simulation study alone. The case shows how the qualitative outcomes of the discrete-event simulation study led to an analysis using the system dynamics technique. The system dynamics technique was able to model the decision-makers in the sales and production process and provide a deeper understanding of the performance of the system. Research limitations/implications - The case study describes a traditional discrete-event simulation study which incorporated an unplanned investigation using system dynamics. Further, case studies using a planned approach to showing consideration of organizational issues in discrete-event simulation studies are required. Then the role of both qualitative data in a discrete-event simulation study and the use of supplementary tools which incorporate organizational aspects may help generate a methodology for discrete-event simulation that incorporates human aspects and so improve its relevance for decision making. Practical implications - It is argued that system dynamics can provide a useful addition to the toolkit of the discrete-event simulation practitioner in helping them incorporate a human aspect in their analysis. Originality/value - Helps decision makers gain a broader perspective on the tools available to them by showing the use of system dynamics to supplement the use of discrete-event simulation. © Emerald Group Publishing Limited.

Reliability analysis for hazard and operability studies

Fault tree analysis is used as a tool within hazard and operability (Hazop) studies. The present study proposes a new methodology for obtaining the exact TOP event probability of coherent fault trees. The technique uses a top-down approach similar to that of FATRAM. This new Fault Tree Disjoint Reduction Algorithm resolves all the intermediate events in the tree except OR gates with basic event inputs so that a near minimal cut sets expression is obtained. Then Bennetts' disjoint technique is applied and remaining OR gates are resolved. The technique has been found to be appropriate as an alternative to Monte Carlo simulation methods when rare events are countered and exact results are needed. The algorithm has been developed in FORTRAN 77 on the Perq workstation as an addition to the Aston Hazop package. The Perq graphical environment enabled a friendly user interface to be created. The total package takes as its input cause and symptom equations using Lihou's form of coding and produces both drawings of fault trees and the Boolean sum of products expression into which reliability data can be substituted directly.

Functional neuroimaging and behavioural studies on global form processing in the human visual system

Magnetoencephalography (MEG), functional magnetic resonance imaging (fMRI) and behavioural experiments were used to investigate the neural processes underlying global form perception in human vision. Behavioural studies using Glass patterns examined sensitivity for detecting radial, rotational and horizontal structure. Neuroimaging experiments using either Glass patterns or arrays of Gabor patches determined the spatio-temporal neural responseto global form. MEG data were analysed using synthetic aperture magnetometry (SAM) to spatially map event-related cortical oscillatory power changes: the temporal sequencing of activity within a discrete cortical area was determined using a Morlet wavelet transform. A case study was conducted to determine the effects of strbismic amblyopia on global form processing: all other observers were normally-sighted. The main findings from normally-sighted observers were: 1) sensitivity to horizontal structure was less than for radial or rotational structure; 2) the neural response to global structure was a reduction in cortical oscillatory power (10-30 Hz) within a network of extrastriate areas, including V4 and V3a; 3) the extend of reduced cortical power was least for horizontal patters; 4) V1 was not identified as a region of peak activity with either MEG or fMRI. The main findings with the strabismic amblyope were: 1) sensitivity for detection of radial, rotational, and horizontal structure was reduced when viewed with the amblyopic- relative to the fellow- eye; 2) cortical power changes within V4 to the presentation of rotational Glass patterns were less when viewed with the amblyopic- compared with the fellow- eye. The main conclusions are: 1) a network of extrastriate cortical areas are involved in the analysis of global form, with the most prominent change in neural activity being a reduction in oscillatory power within the 10-30 Hz band; 2) in strabismic amblyopia, the neuronal assembly associated with form perception in extrastriate cortex may be dysfunctional, the nature of this dysfunction may be a change in the normal temporal pattern of neuronal discharges; 3) MEG, fMRI and behavioural measures support the notion that different neural processes underlie the perception of horizontal as opposed to radial or rotational structure.

(Re)examinando horizontes en los estudios feministas de traducción:¿hacia una tercera ola?

Los feminismos son una de esas teorías marco cuyas contribuciones son perceptibles en todos los ámbitos de la sociedad, incluidos los estudios de traducción. La materialización más evidente de esta interacción es el surgimiento, en los 80, de una corriente de traducción feminista en Canadá, capaz de colocar el género en el centro del debate sobre traducción. En la actualidad, y pese a las críticas y posteriores redefiniciones del concepto de traducción feminista, la propuesta canadiense sigue concibiéndose por lo general como paradigma de interacción entre feminismos y traducción. En este artículo propongo nuevas aproximaciones a la práctica de traducir y paratraducir desde los feminismos, dentro de una tercera ola de traducción feminista. Además, pretendo abrir el debate (re)examinando áreas de interés mutuo para los estudios de traducción y los feminismos en el plano conceptual, historiográfico y crítico, con el propósito de que sugieran nuevas líneas de investigación futura. Feminisms are one of those framework theories that have contributed powerfully to all areas of society, including Translation Studies. The most evident outcome of this interplay is the emergence, in the 1980s, of a Feminist Translation school in Canada, which placed gender in the spotlight. Despite criticism and subsequent redefinitions of the notion of feminist translation, the Canadian school is still generally regarded as the paradigm of interaction between feminisms and translation. The aim of this article is two-fold: firstly, to advance new approaches to the practice of translation and paratranslation from a feminist perspective (within the context of a third wave of feminist translation). Secondly, to open new debates by means of (re)examining topics of mutual interest for both Translation Studies and Feminisms on a conceptual, historical and critical plane, so that subsequent studies can be fostered. Feminisms are one of those framework theories that have contributed powerfully to all areas of society, including Translation Studies. The most evident outcome of this interplay is the emergence, in the 1980s, of a Feminist Translation school in Canada, which placed gender in the spotlight. Despite criticism and subsequent redefinitions of the notion of feminist translation, the Canadian school is still generally regarded as the paradigm of interaction between feminisms and translation. The aim of this article is two-fold: firstly, to advance new approaches to the practice of translation and paratranslation from a feminist perspective (within the context of a third wave of feminist translation). Secondly, to open new debates by means of (re)examining topics of mutual interest for both Translation Studies and Feminisms on a conceptual, historical and critical plane, so that subsequent studies can be fostered.

Empirical studies of corporate governance in China

The thesis aims to provide empirical studies towards Chinese corporate governance. Since China initially established its stock exchange system in the 1990s, it has gone through different stages of changes to become a more market-oriented system. Extensive studies have been conducted in Chinese corporate governance, however, many were theoretical discussion focusing on the early stages and there‘s a general lack of empirical analysis. This paper provides three empirical analysis of the Chinese corporate governance: the overall market discipline efficiency, the impact of capital structure on agency costs, the status of 2005- 2006 reform that substantially modified ownership structure of Chinese listed firms and separated ownership and control of listed firms. The three empirical studies were selected to reflect four key issues that need answering: the first empirical study, using event study to detect market discipline on a collective level. This study filled a gap in the Chinese stock market literature for being the first one ever using cross-market data to test market discipline. The second empirical study endeavoured to contribute to the existing corporate governance literature regarding capital structure and agency costs. Two conclusions can be made through this study: 1) for Chinese listed firms, higher gearing means higher asset turnover ratios and ROE, i.e. more debts seem to reduce agency costs; 2) concentration level of shares appears to be irrelevant with company performance, controlling shareholders didn‘t seem to commit to the improvement of corporate assets utilization or contribute to reducing agency costs. This study addressed a key issue in Chinese corporate governance since the state has significant shareholding in most big listed companies. The discussion of corporate governance in the Chinese context would be completely meaningless without discussing the state‘s role in corporate governance, given that about 2/3 of the almost all shares were non-circulating shares controlled by the state before the 2005-2006 overhaul ownership reform. The third study focused on the 2005-2006 reform of ownership of Chinese listed firms. By collecting large-scale data covering all 64 groups of Chinese listed companies went through the reform by the end of 2006 (accounting for about 97.86% and 96.76% of the total market value of Shanghai (SSE) and Shenzhen Stock Exchange (SZSE) respectively), a comprehensive study about the ownership reform was conducted. This would be first and most comprehensive empirical study in this area. The study of separated ownership and control of listed firm is the first study conducted using the ultimate ownership concept in Chinese context.

Performance management of event processing systems

This thesis is a study of performance management of Complex Event Processing (CEP) systems. Since CEP systems have distinct characteristics from other well-studied computer systems such as batch and online transaction processing systems and database-centric applications, these characteristics introduce new challenges and opportunities to the performance management for CEP systems. Methodologies used in benchmarking CEP systems in many performance studies focus on scaling the load injection, but not considering the impact of the functional capabilities of CEP systems. This thesis proposes the approach of evaluating the performance of CEP engines’ functional behaviours on events and develops a benchmark platform for CEP systems: CEPBen. The CEPBen benchmark platform is developed to explore the fundamental functional performance of event processing systems: filtering, transformation and event pattern detection. It is also designed to provide a flexible environment for exploring new metrics and influential factors for CEP systems and evaluating the performance of CEP systems. Studies on factors and new metrics are carried out using the CEPBen benchmark platform on Esper. Different measurement points of response time in performance management of CEP systems are discussed and response time of targeted event is proposed to be used as a metric for quality of service evaluation combining with the traditional response time in CEP systems. Maximum query load as a capacity indicator regarding to the complexity of queries and number of live objects in memory as a performance indicator regarding to the memory management are proposed in performance management of CEP systems. Query depth is studied as a performance factor that influences CEP system performance.

Medical students' personal experience of high-stakes failure:case studies using interpretative phenomenological analysis

Abstract (provisional): Background Failing a high-stakes assessment at medical school is a major event for those who go through the experience. Students who fail at medical school may be more likely to struggle in professional practice, therefore helping individuals overcome problems and respond appropriately is important. There is little understanding about what factors influence how individuals experience failure or make sense of the failing experience in remediation. The aim of this study was to investigate the complexity surrounding the failure experience from the student’s perspective using interpretative phenomenological analysis (IPA). Methods The accounts of 3 medical students who had failed final re-sit exams, were subjected to in-depth analysis using IPA methodology. IPA was used to analyse each transcript case-by-case allowing the researcher to make sense of the participant’s subjective world. The analysis process allowed the complexity surrounding the failure to be highlighted, alongside a narrative describing how students made sense of the experience. Results The circumstances surrounding students as they approached assessment and experienced failure at finals were a complex interaction between academic problems, personal problems (specifically finance and relationships), strained relationships with friends, family or faculty, and various mental health problems. Each student experienced multi-dimensional issues, each with their own individual combination of problems, but experienced remediation as a one-dimensional intervention with focus only on improving performance in written exams. What these students needed to be included was help with clinical skills, plus social and emotional support. Fear of termination of the their course was a barrier to open communication with staff. Conclusions These students’ experience of failure was complex. The experience of remediation is influenced by the way in which students make sense of failing. Generic remediation programmes may fail to meet the needs of students for whom personal, social and mental health issues are a part of the picture.

Medical management of diabetic retinopathy:fenofibrate and ACCORD eye studies

The approach of all ophthalmologists, diabetologists and general practitioners seeing patients with diabetic retinopathy should be that good control of blood glucose, blood pressure and plasma lipids are all essential components of modern medical management. The more recent data on the use of fenofibrate in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and The Action to Control Cardiovascular Risk in Diabetes (ACCORD) Eye studies is reviewed. In FIELD, fenofibrate (200 mg/day) reduced the requirements for laser therapy and prevented disease progression in patients with pre-existing diabetic retinopathy. In ACCORD Eye, fenofibrate (160 mg daily) with simvastatin resulted in a 40% reduction in the odds of retinopathy progressing over 4 years, compared with simvastatin alone. This occurred with an increase in HDL-cholesterol and a decrease in the serum triglyceride level in the fenofibrate group, as compared with the placebo group, and was independent of glycaemic control. We believe fenofibrate is effective in preventing progression of established diabetic retinopathy in type 2 diabetes and should be considered for patients with pre-proliferative diabetic retinopathy and/or diabetic maculopathy, particularly in those with macular oedema requiring laser. © 2011 Macmillan Publishers Limited All rights reserved.

The relationship between spoken language and speech and nonspeech processing in children with autism:a magnetic event-related field study

It has been proposed that language impairments in children with Autism Spectrum Disorders (ASD) stem from atypical neural processing of speech and/or nonspeech sounds. However, the strength of this proposal is compromised by the unreliable outcomes of previous studies of speech and nonspeech processing in ASD. The aim of this study was to determine whether there was an association between poor spoken language and atypical event-related field (ERF) responses to speech and nonspeech sounds in children with ASD (n = 14) and controls (n = 18). Data from this developmental population (ages 6-14) were analysed using a novel combination of methods to maximize the reliability of our findings while taking into consideration the heterogeneity of the ASD population. The results showed that poor spoken language scores were associated with atypical left hemisphere brain responses (200 to 400 ms) to both speech and nonspeech in the ASD group. These data support the idea that some children with ASD may have an immature auditory cortex that affects their ability to process both speech and nonspeech sounds. Their poor speech processing may impair their ability to process the speech of other people, and hence reduce their ability to learn the phonology, syntax, and semantics of their native language.