Bifurcations of optimal vector fields in the shallow lake model

The solution structure of the set of optimal solutions of the shallow lake problem, a problem of optimal pollution management, is studied as we vary the values of the system parameters: the natural resilience, the relative importance of the resource for social welfare and the future discount rate. We find parameter values at which qualitative changes occur. Using theoretical results on the bifurcations of the solution structure to infinite horizon optimization problems obtained earlier, we give a fairly complete bifurcation analysis of the shallow lake problem. In particular, we show how the increase of the discount rate affects the parameter regions where an oligotrophic steady state, corresponding to low pollution level, is globally stable or locally stable under optimal dynamics. Asymptotically, an increase of the discount rate can be offset with a proportional increase of the relative social weight of the resource.

A Question of Evidence: A Critique of Risk Assessment Models Used in the Justice System

This report explores the problems with the present state of risk assessment in the justice field as we at NCCD see them. The critique offered here is the result of many conversations with others in the justice community as well as a review of predictive research conducted in other fields. We recognize that much of what is presented is contrary to current understanding and acceptance, but we hope that it clarifies what evidence is required for the designation of best practice

The Instrumental Genesis of Collective Activity. The Case of an ERP Implementation in a Large Electricity Producer

Collective activity should be a focal subject to study organizational dynamics, particularly in relation with the implementation of management systems such as ERPs. Collective activity is analyzed here as an ongoing dialogical construction by actors. It is always mediated by signs and particularly by instruments. To design and adapt collective activity, a reflexive dialogical exchange between actors, a “collective activity about collective activity”, mediated by instruments, is necessary: we call it “the instrumental genesis of collective activity”. We analyze the case of an ERP implementation at EDF, a large electricity company, in the purchase and procurement area of the production division. The design and implementation of the new system was not clearly viewed as the instrumental genesis of collective activity. Difficulties appeared particularly for cross-functional cooperation and for the construction of new professional profiles of competence. In the light of this case, we suggest that key conditions for the intelligibility and the actionability of collective activity are the establishment of communities and the hybridization of professional competences.Collective Activity; Collective Sensemaking; Community; Dialogical; ERP; Instruments; Instrumental Genesis of Activity; Interpretation; Sign

Environmental impact assessment of electricity production by photovoltaic system using GEOSS recommendations on interoperability

International audienceWithin the Architecture Implementation Pilot (AIP-3) of GEOSS, we have developed a scenario called "environmental impact assessment of the production, transportation and use of energy for the photovoltaic (PV) sector through Life Cycle Assessment (LCA)". It aims at providing decision-makers and policy-planners with reliable and geo-localized knowledge of several impacts induced by various technologies of the PV sector. The scenario is implemented in the GEOSS Common Infrastructure (GCI) and benefits from the GEOSS interoperability arrangements. The FP7-co-funded EnerGEO project provides a GEOSS compliant Catalogue Service for the Web (CSW) that permits to discover the Web Processing Service (WPS) allowing computation of the environmental impact. A WebGIS client provided by the FP7-co-funded GENESIS platform allows users to interact with geospatial data and computation processes. This scenario has proven to be an efficient tool to disseminate knowledge on environmental impacts related to PV because of the GEOSS capabilities in interoperability

Creativity: Can Artistic Perspectives Contribute to Management Questions?

Today creativity is considered as a necessity in ail aspects of management. This working paper mirrors the artistic and managerial conceptions of creativity. Although there are shared points in bath applications, however deep-seated and radically opposed traits account for the divergence between the two fields. This exploratory analysis opens up new research questions and insights into practices.Creativity; Management; Art

Impact of working capital management on the profitability of smes through cash operation cycles in Kumasi

A business ought to be able to breed an adequate amount of cash and cash equivalent to meet its short-term liabilities if it is to carry on and develop in business. For that reason, working capital management which helps an entity to, efficiently and effectively manage current assets and liabilities is a key factor in the company’s long-term success; without working capital, the non- current assets will not function. The better the degree to which current assets exceed current liability, the more solvent or liquid a company is likely to be. This paper observes the relationship between working capital management practices of small and medium enterprises (SMEs) and the performance and profitability of these businesses in the Kumasi Metropolis distinctively Asafo, to evaluate key ratios of industries of such working capital management policies in ensuring that current assets meets current liabilities, to assess the degree to which management of SMEs are dedicated to the effective and efficient management of working capital. The implication of the findings is that the government of Ghana should pursue policies aimed at encouraging training and improving the managerial skills of SME owner/managers as well as creating the enabling environment for the development of improved modern technologies to transform the business processes of these vital industries

Intelligent design of manufacturing systems.

The design of a manufacturing system is normally performed in two distinct stages, i.e. steady state design and dynamic state design. Within each system design stage a variety of decisions need to be made of which essential ones are the determination of the product range to be manufactured, the layout of equipment on the shopfloor, allocation of work tasks to workstations, planning of aggregate capacity requirements and determining the lot sizes to be processed. This research work has examined the individual problem areas listed above in order to identify the efficiency of current solution techniques and to determine the problems experienced with their use. It has been identified that for each design problem. although there are an assortment of solution techniques available, the majority of these techniques are unable to generate optimal or near optimal solutions to problems of a practical size. In addition, a variety of limitations have been identified that restrict the use of existing techniques. For example, existing methods are limited with respect to the external conditions over which they are applicable and/or cannot enable qualitative or subjective judgements of experienced personnel to influence solution outcomes. An investigation of optimization techniques has been carried out which indicated that genetic algorithms offer great potential in solving the variety of problem areas involved in manufacturing systems design. This research has, therefore, concentrated on testing the use of genetic algorithms to make individual manufacturing design decisions. In particular, the ability of genetic algorithms to generate better solutions than existing techniques has been examined and their ability to overcome the range of limitations that exist with current solution techniques. IIFor each problem area, a typical solution has been coded in terms of a genetic algorithm structure, a suitable objective function constructed and experiments performed to identify the most suitable operators and operator parameter values to use. The best solution generated using these parameters has then been compared with the solution derived using a traditional solution technique. In addition, from the range of experiments undertaken the underlying relationships have been identified between problem characteristics and optimality of operator types and parameter values. The results of the research have identified that genetic algorithms could provide an improved solution technique for all manufacturing design decision areas investigated. In most areas genetic algorithms identified lower cost solutions and overcame many of the limitations of existing techniques

Optimising economic, environmental, and social objectives: a goal-programming approach in the food sector

The business-decision environment is increasingly complicated by the emergence of competing economic, environmental, and social goals, a notion typified by the current pressures of global economic instability and climate-change targets. Trade-offs are often unclear and contributions by different actors and stakeholders in the supply chain may be unequal but, due to the interdependencies between businesses and stakeholders in relation to total environmental or social impact, a whole chain, simultaneous, and strategic approach is required. After a review of relevant literature and the identification of knowledge gaps, the author introduces and illustrates the use of goal programming as a technique that could facilitate this approach and uses real case evidence for alternative food supply chain strategies, at local, regional, and national levels. It is shown that the method can simplify a complex simultaneous decision situation into a useful and constructive decision and planning framework. Results show how a priori beliefs may be challenged and how operational and resource efficiency could be improved through the use of such a model, which enables a broad stakeholder appreciation and the opportunity to explore and test new environmental or social challenges