Scheduling of non-repetitive lean manufacturing systems under uncertainty using intelligent agent simulation

World-class manufacturing paradigms emerge from specific types of manufacturing systems with which they remain associated until they are obsolete. Since its introduction the lean paradigm is almost exclusively implemented in repetitive manufacturing systems employing flow-shop layout configurations. Due to its inherent complexity and combinatorial nature, scheduling is one application domain whereby the implementation of manufacturing philosophies and best practices is particularly challenging. The study of the limited reported attempts to extend leanness into the scheduling of non-repetitive manufacturing systems with functional shop-floor configurations confirms that these works have adopted a similar approach which aims to transform the system mainly through reconfiguration in order to increase the degree of manufacturing repetitiveness and thus facilitate the adoption of leanness. This research proposes the use of leading edge intelligent agent simulation to extend the lean principles and techniques to the scheduling of non-repetitive production environments with functional layouts and no prior reconfiguration of any form. The simulated system is a dynamic job-shop with stochastic order arrivals and processing times operating under a variety of dispatching rules. The modelled job-shop is subject to uncertainty expressed in the form of high priority orders unexpectedly arriving at the system, order cancellations and machine breakdowns. The effect of the various forms of the stochastic disruptions considered in this study on system performance prior and post the introduction of leanness is analysed in terms of a number of time, due date and work-in-progress related performance metrics

Application of lean scheduling and production control in non-repetitive manufacturing systems using intelligent agent decision support

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Lean Manufacturing (LM) is widely accepted as a world-class manufacturing paradigm, its currency and superiority are manifested in numerous recent success stories. Most lean tools including Just-in-Time (JIT) were designed for repetitive serial production systems. This resulted in a substantial stream of research which dismissed a priori the suitability of LM for non-repetitive non-serial job-shops. The extension of LM into non-repetitive production systems is opposed on the basis of the sheer complexity of applying JIT pull production control in non-repetitive systems fabricating a high variety of products. However, the application of LM in job-shops is not unexplored. Studies proposing the extension of leanness into non-repetitive production systems have promoted the modification of pull control mechanisms or reconfiguration of job-shops into cellular manufacturing systems. This thesis sought to address the shortcomings of the aforementioned approaches. The contribution of this thesis to knowledge in the field of production and operations management is threefold: Firstly, a Multi-Agent System (MAS) is designed to directly apply pull production control to a good approximation of a real-life job-shop. The scale and complexity of the developed MAS prove that the application of pull production control in non-repetitive manufacturing systems is challenging, perplex and laborious. Secondly, the thesis examines three pull production control mechanisms namely, Kanban, Base Stock and Constant Work-in-Process (CONWIP) which it enhances so as to prevent system deadlocks, an issue largely unaddressed in the relevant literature. Having successfully tested the transferability of pull production control to non-repetitive manufacturing, the third contribution of this thesis is that it uses experimental and empirical data to examine the impact of pull production control on job-shop performance. The thesis identifies issues resulting from the application of pull control in job-shops which have implications for industry practice and concludes by outlining further research that can be undertaken in this direction

Definition of timing in the control of the 1st generation Lasioderma serricorne adults, inside tobacco stores, based on the development of the oocytes

Στην παρούσα εργασία μελετήθηκε με τη μέθοδο της διάνοιξης της κοιλιακής χώρας, η εξέλιξη των ωοθηκών του L. serricorne (F.) (Coleoptera: Anobiidae) των σταδίων της νύμφτις Tou θήλεως και του ακμαίου του ευρισκόμενου στο κελί της νύμφωσης. Ο προσδιορισμός του χρόνου σύζευξης και έναρξης της ωοτοκίας του L. serricorne σε συνδυασμό με την ου6ό ανάπτυξης, συνετέλεσαν στον καθορισμό του σωστού χρόνου εφαρμογής της πρώτες αποτελεσματικής επέμβασης εναντίον των ακμαίων της 1ης γενεάς.The development of the oocytes of pupae, females inside the pupal cell and after emergence of Lasioderma serricorne (F.) (Coleoptera: Anobiidae) was studied by dissecting their abdomen. The time of oocytes maturation as well as that of the starting of their oviposition, in combination with the insect’s developmental threshold was determined, aiming to time the 1st effective control against the emerging adults of the 1st generation

Is existing legislation fit-for-purpose to achieve Good Environmental Status in European seas?

Recent additions to marine environmental legislation are usually designed to fill gaps in protection and management, build on existing practices or correct deficiencies in previous instruments. Article 13 of the European Marine Strategy Framework Directive (MSFD) requires Member States to develop a Programme of Measures (PoM) by 2015, to meet the objective of Good Environmental Status (GES) for their waters by 2020. This review explores key maritime-related policies with the aim to identify the opportunities and threats that they pose for the achievement of GES. It specifically examines how Member States have relied on and will integrate existing legislation and policies to implement their PoM and the potential opportunities and difficulties associated with this. Using case studies of three Member States, other external impediments to achieving GES are discussed including uses and users of the marine environment who are not governed by the MSFD, and gives recommendations for overcoming barriers

Counterfeit purchase typologies during an economic crisis

Purpose-The economic crisis has become a global phenomenon, although in Europe it mostly affected the Mediterranean countries of Southern Europe. In times of economic stress, counterfeit products increase their market share. In this context this paper aims to explore, and attempt to explain, consumer perspectives on the purchasing of counterfeit brands. Methodology-The study utilized an e-mail based open ended questionnaire as its data collection method. The research used a sample of 83 participants belonging to generation Y (younger and older) and upper medium and high income class brackets. Findings-Purchasing behaviour of counterfeit products during the economic crisis enabled us to identify four types of consumers. Furthermore, the results indicated that some consumers have significant interest in counterfeits while some consumers show apathy or indifference towards counterfeiting. Furthermore, some consumers believe that the government’s economic austerity policies cause high level consumption of counterfeits while others consider the authorities to be responsible for counterfeiting, since they do not adequately tackle it. Research limitations/implications- This research is exploratory in nature and restricted to Greek generation Y consumers. Suggestions are presented regarding future studies and generalization of the findings. Practical implications- Implementation of law, joint communication campaigns and social media usage are the major implications for the stakeholders in the marketplace. Originality/value-This study extends the body of knowledge of purchasing behavior on non-deceptive counterfeit products by offering empirical findings from Greece, a country facing a severe economic crisis. To our knowledge this is the first study that explores counterfeit buying behaviour during an economic crisis perio

A Saxon Fish Weir and undated fish trap frames near Ashlett Creek, Hampshire, UK: static structures on a dynamic foreshore

This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.The remains of a wooden V-shaped fish weir and associated structures have been discovered near Ashlett Creek on the tidal mudflats of Southampton Water in Hampshire, southern Britain. Radiocarbon dating of oak roundwood stakes taken from the main weir structure date it to the middle Saxon period. Clusters of as-yet undated roundwood posts within the catchment area of the weir are interpreted as the frames for fish traps that are assumed to pre- or post-date the operational period of the weir itself. The weir is contemporary with wooden V-shaped fish weirs found elsewhere in southern and central Britain, and also Ireland, but its circular catchment ‘pound’ remains restricted, in these islands, to the Solent and Severn estuaries: it has a close parallel with another Saxon-era weir on the nearby Isle of Wight. It also shows striking structural similarities with examples in use today in Basse Normandy, on the southern shore of the English Channel. The paper discusses the function and operation of the weir, and places it in its social and historical context. Regressive cartography demonstrates that the structures have become exposed as a result of saltmarsh retreat in this area of Southampton Water since the 19th century. The radiocarbon dates returned for the posts demonstrate that this transgression of the marsh must have been preceded by a prolonged period of progradation, which covered and preserved the site; its subsequent re-exposure has negative implications for its survival.The fieldwork underpinning this research was carried out using equipment and facilities provided by the Centre for Maritime Archaeology of the University of Southampton. The authors themselves met incidental costs. Radiocarbon dating was financed from an internal University of Exeter research allowance