41,715 research outputs found

    System Dynamics in Food Quality Certifications: Development of an Audit Integrity System

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    Due to the complex structure of certification schemes the risk of flaws and scandals is generally high. It has further increased by several developments during the last years. With regard to their potential effects, it is questionable whether the certification approaches are actually able to detect deficiencies within the system and thus prevent crises which may lead to its breakdown. Hence, the ability of a standard to meet its objectives of food quality and safety needs to be enforced. In this contribution we launch the implementation of a controlling tool which automatically monitors audit quality based on information of the respective data bases. By analysing possible negative influences, opportunistic behaviour can thus be detected.certification, quality assurance systems, risk oriented auditing approach, Food Consumption/Nutrition/Food Safety, Food Security and Poverty,

    Modelling the feedback effects of reconfiguring health services

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    The shift in the balance of health care, bringing services ‘closer to home’, is a well-established trend, which has been motivated by the desire to improve the provision of services. However, these efforts may be undermined by the improvements in access stimulating demand. Existing analyses of this trend have been limited to isolated parts of the system with calls to control demand with stricter clinical guidelines or to meet demand with capacity increases. By failing to appreciate the underlying feedback mechanisms, these interventions may only have a limited effect. We demonstrate the contribution offered by system dynamics modelling by presenting a study of two cases of the shift in cardiac catheterization services in the UK. We hypothesize the effects of the shifts in services and produce model output that is not inconsistent with real world data. Our model encompasses several mechanisms by which demand is stimulated. We use the model to clarify the roles for stricter clinical guidelines and capacity increases, and to demonstrate the potential benefits of changing the goals that drive activity

    Marketing competition on a new product introduction - a structural analysis using systems thinking

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    Launching a new product on the market is a strategic activity that needs specific investments and a specific organisation. There are multiple factors that determine the success of a new product on the market but their direct effects are not often very well observable (marketing for example). With this study, we analysed the systemic structure underlying the dynamics related to the introduction of a new product on the market. In particular, we built a qualitative model based on the systems thinking methodology of causal-loop diagrams (CLDs), starting from the main structure and assumptions of the well-known Bass model. The model provides a systemic perspective on the interdependencies among various aspects that interact in important organisational areas. The presented causal-loop diagram tries to describe the systems structure which is intrinsic to the introduction and diffusion of a new product on the market, and how ultimately the related dynamics could be manage

    The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

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    The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb--Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.Comment: 55 pages, 82 figure

    Identifying Success Factors in Construction Projects: A Case Study

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    © 2015 by the Project Management Institute. Published online in Wiley Online Library. Defining "project success" has been of interest for many years, and recent developments combine multiple measurable and psychosocial factors that add to this definition. There has also been research into success factors, but little research into the causal chains through which success emerges. Following the multi-dimensionality of "success," this article shows how success factors combine in complex interactions; it describes factors contributing to project performance by a company working on two major construction programs and shows how to map and analyze paths from root causes to success criteria. The study also identifies some specific factors - some generic, some context-dependent - none of these is uncommon but here they come together synergistically

    Simulation analysis of the consequences of shifting the balance of health care: a system dynamics approach

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    Objectives: The shift in the balance of health care, bringing services 'closer to home', is a well-established trend. This study sought to provide insight into the consequences of this trend, in particular the stimulation of demand, by exploring the underlying feedback structure. Methods: We constructed a simulation model using the system dynamics method, which is specifically designed for the analysis of feedback structure. The model was calibrated to two cases of the shift in cardiac catheterization services in the UK. Data sources included archival data, observations and interviews with senior health care professionals. Key model outputs were the basic trends displayed by waiting lists, average waiting times, cumulative patient referrals, cumulative patient activity and cumulative overall costs. Results: Demand was stimulated in both cases via several different mechanisms. We revealed the roles for clinical guidelines and capacity changes, and the typical responses to imbalances between supply and demand. Our analysis also demonstrated the potential benefits of changing the goals that drive activity by seeking a waiting list goal rather than a waiting time goal. Conclusions: Appreciating the wider consequences of shifting the balance of care is essential if services are to be improved overall. The underlying feedback mechanisms of both intended and unintended effects need to be understood. Using a systemic approach, more effective policies may be designed through coordinated programmes rather than isolated initiatives, which may have only a limited impact
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