896,069 research outputs found

    Decision modelling tools for utilities in the deregulated energy market

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    This thesis examines the impact of the deregulation of the energy market on decision making and optimisation in utilities and demonstrates how decision support applications can solve specific encountered tasks in this context. The themes of the thesis are presented in different frameworks in order to clarify the complex decision making and optimisation environment where new sources of uncertainties arise due to the convergence of energy markets, globalisation of energy business and increasing competition. This thesis reflects the changes in the decision making and planning environment of European energy companies during the period from 1995 to 2004. It also follows the development of computational performance and evolution of energy information systems during the same period. Specifically, this thesis consists of studies at several levels of the decision making hierarchy ranging from top-level strategic decision problems to specific optimisation algorithms. On the other hand, the studies also follow the progress of the liberalised energy market from the monopolistic era to the fully competitive market with new trading instruments and issues like emissions trading. This thesis suggests that there is an increasing need for optimisation and multiple criteria decision making methods, and that new approaches based on the use of operations research are welcome as the deregulation proceeds and uncertainties increase. Technically, the optimisation applications presented are based on Lagrangian relaxation techniques and the dedicated Power Simplex algorithm supplemented with stochastic scenario analysis for decision support, a heuristic method to allocate common benefits and potential losses of coalitions of power companies, and an advanced Branch-and-Bound algorithm to solve efficiently non-convex optimisation problems. The optimisation problems are part of the operational and tactical decision making process that has become very complex in the recent years. Similarly, strategic decision support has also faced new challenges. This thesis introduces two applications involving multiple criteria decision making methods. The first application explores the decision making problem caused by the introduction of 'green' electricity that creates additional value for renewable energy. In this problem the stochastic multi-criteria acceptability analysis method (SMAA) is applied. The second strategic multi-criteria decision making study discusses two different energy-related operations research problems: the elements of risk analysis in the energy field and the evaluation of different choices with a decision support tool accommodating incomplete preference information to help energy companies to select a proper risk management system. The application is based on the rank inclusion in criteria hierarchies (RICH) method.reviewe

    Classification and quantification of risk factors and treatment strategies for ocular hypertension and primary open-angle glaucoma

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    AIM: A systematic synthesis of the existing research evidence in the field of POAG is an appropriate methodological approach to achieve the aim of improved overall management of the disease. In the present study we focused on evidence on risk factors other than intraocular pressure (IOP) that are potentially modifiable and/or could be used for timely identification of people at high risk of POAG; and on relative efficacy, tolerability and cost-effectiveness profile of mono-compound topical IOP-lowering medications in treatment of POAG/OHT. METHODS: Systematic review of systematic reviews/meta-analysis of primary prognostic studies and randomized controlled trials (RCTs). A thorough and sensitive search of Medline, Scopus and Cochrane Databases was performed. Methodological quality of reviews and quality of evidence were assessed using the AMSTAR checklist and the GRADE system, respectively. Comprehensive Meta-Analysis softaware version 2.2.064 2011 ( Biostat Inc., Englewood, NJ, USA) and SAS for Windows 9.2 (SAS Institute Inc., Cary, NC, USA) (macros for multiple modifier meta-regression) were used for data analyses. Conclusions were based on the evaluation of the best available evidence. RESULTS: 3606 records were identified through two different search strategies; 25 studies met the inclusion criteria for evaluation of POAG risk factors and 16 for the evaluation of efficacy and safety of mono-compound topical IOP-lowering drugs. Only six reviews achieved an overall "moderate” quality of evidence. Reviews dealing with risk factors were of low quality in general, whereas individual studies indicated that there were no association between smoking and POAG and a weakly increased risk of POAG in diabetic women. “Moderate quality” reviews dealing with therapy indicate that prostaglandin analogues (PGAs) should be considered equivalent regarding efficacy, but latanoprost is relevantly better tolerated than bimatoprost or latanoprost. Non-PGA compounds do not relevantly differ between each other in either efficacy or safety. Timolol and brimonidine are relevantly less effective than all PGAs. The same is true for CAI vs. bimatoprost. Regarding tolerability, timolol is superior to all PGAs and brimonidine and CAI are superior to bimatoprost. Conclusion: Several potential risk factors for POAG apart from IOP were identified, however, no conclusion regarding their contribution could be drawn as the available information derives from low quality evidence. Available evidence of mono-compound IOP-lowering medications in treatment of POAG/OHT was identified. Moderate quality evidence indicates latanoprost as a mono-compound topical treatment with a most favourable trade-off between benefits and harms

    A Framework for Assessing Environmental Incidents in Coastal Areas: A Case Study in the Southeastern Coastal Area of Vietnam

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    As developing dynamic regions, coastal areas have a high potential for environmental incidents, especially chemical spills, which may permanently threaten livelihoods and coastal ecosystems. Establishing an appropriate methodological framework for assessing environmental incidents in coastal areas, ensuring increased predictability and minimising potential consequences is a trend of interest to scientists. In this study, the environmental risk assessment model was applied to develop a framework for assessing environmental incidents in coastal areas due to chemical spills from the mainland based on hazard, exposure and vulnerability factors (i.e., sensitivity and adaptability). Using the multiple criteria decision-making (MCDM) method approach, suitable criteria, their optimal weights and the risk factors were determined. Modelling, remote sensing, and geographic information system (GIS) methods were used simultaneously for data collection, evaluation, and mapping. A case study was conducted in the coastal area of southeastern Vietnam, which comprises 27 subregions. These were classified into four environmental incident levels: low, medium, high, and extreme. Their prevalence was 70.37%, 3.70%, 7.41%, and 18.52% in the rainy season, and 74.07%, 7.41%, 7.41%, and 11.11% in the dry season, respectively. Based on analysis results and consultation with managers and experts, pertinent and practical solutions were proposed to reduce the risk of environmental incidents in subregions with high and extreme incident levels. Our results are expected to support policymakers in decision-making related to the sustainable development of the study area and complete the methodology framework for assessing environmental incidents in coastal areas due to multiple hazards

    Sustainability experiments in the agri-food system : uncovering the factors of new governance and collaboration success

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    In recent years, research, society and industry recognize the need to transform the agri-food system towards sustainability. Within this process, sustainability experiments play a crucial role in transforming the structure, culture and practices. In literature, much attention is given to new business models, even if the transformation of conventional firms toward sustainability may offer opportunities to accelerate the transformation. Further acceleration could be achieved through collaboration of multiple actors across the agri-food system, but this calls for a systems approach. Therefore, we developed and applied a new sustainability experiment systems approach (SESA) consisting of an analytical framework that allows a reflective evaluation and cross-case analysis of multi-actor governance networks based on business and learning evaluation criteria. We performed a cross-case analysis of four agri-food sustainability experiments in Flanders to test and validate SESA. Hereby, the key factors of the success of collaboration and its performance were identified at the beginning of a sustainability experiment. Some of the key factors identified were risk sharing and the drivers to participate. We are convinced that these results may be used as an analytical tool for researchers, a tool to support and design new initiatives for policymakers, and a reflective tool for participating actors

    Multi crteria decision making and its applications : a literature review

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    This paper presents current techniques used in Multi Criteria Decision Making (MCDM) and their applications. Two basic approaches for MCDM, namely Artificial Intelligence MCDM (AIMCDM) and Classical MCDM (CMCDM) are discussed and investigated. Recent articles from international journals related to MCDM are collected and analyzed to find which approach is more common than the other in MCDM. Also, which area these techniques are applied to. Those articles are appearing in journals for the year 2008 only. This paper provides evidence that currently, both AIMCDM and CMCDM are equally common in MCDM

    The fiscal case for working with troubled families: analysis and evidence on the costs of troubled families to government

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    Recommender Thermometer for Measuring the Preparedness for Flood Resilience Management

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    A range of various thermometers and similar scales are employed in different human and resilience management activities: Distress Thermometer, Panic Thermometer, Fear Thermometer, fire danger rating, hurricane scales, earthquake scales (Richter Magnitude Scale, Mercalli Scale), Anxiety Thermometer, Help Thermometer, Problem Thermometer, Emotion Thermometer, Depression Thermometer, the Torino scale (assessing asteroid/comet impact prediction), Excessive Heat Watch, etc. Extensive financing of the preparedness for flood resilience management with overheated full-scale resilience management might be compared to someone ill running a fever of 41°C. As the financial crisis hits and resilience management financing cools down it reminds a sick person whose body temperature is too low. The degree indicated by the Recommender Thermometer for Measuring the Preparedness for Flood Resilience Management with a scale between Tmin=34,0° and Tmax=42,0° shows either cool or overheated preparedness for flood resilience management. The formalized presentation of this research shows how changes in the micro, meso and macro environment of resilience management and the extent to which the goals pursued by various interested parties are met cause corresponding changes in the “temperature” of the preparedness for resilience management. Global innovative aspects of the Recommender Thermometer developed by the authors of this paper are, primarily, its capacity to measure the “temperature” of the preparedness for flood resilience management automatically, to compile multiple alternative recommendations (preparedness for floods, including preparing your home for floods, taking precautions against a threat of floods, retrofitting for flood-prone areas, checking your house insurance; preparedness for bushfires, preparedness for cyclones, preparedness for severe storms, preparedness for heat waves, etc.) customised for a specific user, to perform multiple criteria analysis of the recommendations, and to select the ten most rational ones for that user. Across the world, no other system offers these functions yet. The Recommender Thermometer was developed and fine-tuned in the course of the Android (Academic Network for Disaster Resilience to Optimise educational Development) project

    A Decision Making System for Selecting Sustainable Technologies for Retail Buildings

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    CIB Publication 382: Selected papers presented at the CIB World Building Congres Construction and Society, Brisbane 5-9 May 2013 Papers from the Designated Session TG66 - Energy and the Built EnvironmentThe implementation of sustainable technologies can improve the energy and carbon efficiency of existing retail buildings. However, the selection of an appropriate sustainable technology is a complex task due to the large number of technological alternatives and decision criteria that need to be considered. Also, there exist series of uncertainties that are associated with the use of sustainable technologies, but have to be evaluated to achieve realistic and transparent results. The selection of sustainable technology is therefore most challenging. An earlier study was conducted with UK experienced practitioners including clients/developers, engineers, contractors and suppliers to identify the drivers and barriers for the use of sustainable technologies in UK retail construction. One major barrier identified from the study was the lack of a decision making tool, highlighted by both construction professionals and stakeholders in the retail industry. The large number of alternatives and potential solutions require a decision support method to be implemented. Information data on the economic variables, energy performance and impact on the environment of these systems is presently affected by vagueness and lack of knowledge. To deal with this high level of complexity and uncertainty an evaluation support approach is needed. This paper aims to develop a decision making framework to assist both retailers and construction professionals to define and evaluate the selection of sustainable technological options for delivering retail buildings. The research was carried out through a combination of a critical literature review and a survey-based study using expert opinions of retailers and contractors. The developed framework of decision criteria should provide a sustainable technology model to assist both construction professionals and stakeholders in the retail industry to systematically and effectively select the most appropriate technology. This approach should make the decision progression more transparent and facilitate sustainable development of retail buildings in achieving the carbon targets set by the UK and other governments

    VR-PMS: a new approach for performance measurement and management of industrial systems

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    A new performance measurement and management framework based on value and risk is proposed. The proposed framework is applied to the modelling and evaluation of the a priori performance evaluation of manufacturing processes and to deciding on their alternatives. For this reason, it consistently integrates concepts relevant to objectives, activity, and risk in a single framework comprising a conceptual value/risk model, and it conceptualises the idea of value- and risk based performance management in a process context. In addition, a methodological framework is developed to provide guidelines for the decision-makers or performance evaluators of the processes. To facilitate the performance measurement and management process, this latter framework is organized in four phases: context establishment, performance modelling, performance assessment, and decision-making. Each phase of the framework is then instrumented with state of-the-art quantitative analysis tools and methods. For process design and evaluation, the deliverable of the value- and risk-based performance measurement and management system (VR-PMS) is a set of ranked solutions (i.e. alternative business processes) evaluated against the developed value and risk indicators. The proposed VR-PMS is illustrated with a case study from discrete parts manufacturing but is indeed applicable to a wide range of processes or systems
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