A multiple dispatch and partial backup hypercube queuing model to analyze emergency medical systems on highways

The hypercube is a spatially distributed queuing model based on Markovian analysis approximations, used to analyze the configuration and operation of server-to-customer emergency systems. In the present study we adapted the model to analyze emergency medical systems (EMS) on highways, which operate within particular dispatching policies. The study takes into consideration that: the emergency calls are of different types; the servers are distinct (e.g., rescue ambulances, medical vehicles); only certain servers in the system can service calls in a given region (partial backup); and, depending on the type of call, one or more identical or distinct servers are immediately dispatched to service such calls (multiple dispatch). We also consider that the arriving calls take place either along the highway or at the home location of a server – in which case the server does not need to travel to the call location. Finally, we analyzed the computational results of applying such an approach to the case study of an EMS operating on Brazilian highways.     

Loading optimization of palletized products on trucks

In this paper we analyze the application of an optimization model to solve problems of arranging products (packed in boxes) on pallets, and arranging loaded pallets on trucks. Initially the model is applied to solve thousands of randomly generated experiments. Then, in order to assess the effectiveness of the solutions in practice, the model is applied to two Brazilian case studies: a food company distribution center and a large wholesale distribution center. We also discuss the use of this approach for optimizing the sizes of packages, pallets and trucks. In particular, we analyze the performance of the Brazilian standard pallet (PBR), adopted by the Brazilian Association of Supermarkets (ABRAS) and recommended by the Brazilian Logistics Association (ASLOG), in comparison with other standard pallets. By examining not only the loading of products on pallets, but also the loading of pallets on trucks, we can obtain global utilization indices which are useful to evaluate the economical performance of unit load systems in the logistics chain of a company.     

Getting fourteen for the price of one! Understanding the factors that influence land value and how they affect biodiversity conservation in central Brazil

Biodiversity policies are suffering an implementation crisis; the roots are deeply entrenched in the unfair competition between the public and private interests for suitable versus available land. In this article we propose a value-based equivalence method for compensation for the 20% compulsory reserves in the Taquari River sub-catchments, as legally required for central savannas of Brazil. Using regression techniques we analyzed 106 land deals in the Pantanal's watershed and identified the most significant variables influencing land value. We argue that the commonly used area-for-area, compensation mechanism, where 1 ha of compulsory reserve is missing, requires another hectare protected in the same catchments, instead of counteract habitat loss, is in fact harmful to biodiversity, stimulating progressive habitat destruction. We identified the economic forces behind deforestation and habitat fragmentation in the central savannahs of Brazil and proposed a market-based approach to counteract these forces using tools already available in environmental economics. We suggest that a dollar-for-dollar reference to determine land equivalence and compensation can better counter-balance the incremental losses from habitat destruction, while providing objectivity and transparency for trading alternatives.     

On the index tracking and the statistical arbitrage choosing the stocks by means of cointegration: the role of stock picking

In this paper, we propose a new methology for Index Tracking (IT) by means of cointegration which provides some significant improvements on that field. As the quality of the tracking portfolio (TP) depends highly on the stock selection procedure, we propose picking the stocks using a model selection technique based on optimizing the cointegration level of the TP and the benchmark index instead of selecting, as in previous papers the assets by ad hoc decisions. To illustrate an empirical application of these techniques we use daily closing prices in the Dow Jones Industrial Average (DJIA) index over two different periods; one period which goes from 1 January 1990 to 31 December 2001 previously used by other authors, and the bear and a turmoil period, which goes from January 2007 to May 2012, inside the current financial crisis. Using only five assets we are able to successfully track the DJIA index and our results improve the IT technique based on cointegration that chooses stocks with maximum capitalization level. We also have compared our results with a more traditional procedure based on correlation and again our results reveal superiority. The empirical illustration not only has been focused on the TP itself, but has also been extended to tracking the index with an added profitability of 5, 10, 15 or 20% and to long-short strategies, producing profitable results.     

Non-homogeneous servers in emergency medical systems: Practical applications using the hypercube queueing model

In this paper, we study the effects of considering homogeneous versus non-homogeneous servers in applications of the hypercube queueing model. This is important since approximate methods available for solving the model for homogeneous servers are computationally much less time-consuming than the exact methods required for the non-homogeneous case. Illustrative examples are initially presented to show the degree to which using homogeneous versus non-homogeneous servers can differ. Then, two ambulance deployment applications dealing with Brazilian emergency medical systems, in a city and along a highway, are analyzed. The basic operational characteristics of non-homogeneous systems were compared to the respective predictions produced under the simplifying assumption of homogeneous servers. It was found that, even when the degree of non-homogeneity of the servers is not highly significant, homogeneity may lead to poor predictions of the actual operational characteristics of non-homogeneous systems.     

Economic Analysis of the Policy for Accreditation of Dairy Farms Free of Bovine Brucellosis and Tuberculosis: Challenges for Small and Large Producers in Brazil

One of the cornerstones of the National Program for Control and Eradication of Bovine Brucellosis and Tuberculosis in Brazil is the voluntary accreditation of free herds. We developed a stochastic cost–benefit analysis model for two types of dairy herds (high yield Holstein‐Zebu crossbred females and lower productivity smaller scale herds) to identify the technical and economic constraints of this process. The initial prevalence of infected animals and the impact of the disease in the structure and performance of the herd were derived from secondary data. Information on the costs and benefits of herd sanitation were compiled into a cost–benefit model at the herd level. The last step consisted of a scenario simulation to evaluate the impact of alternative policies to the certification process. For each scenario, we calculate the probability over time of a Benefit–Cost Ratio greater than 1 and of an Internal Rate of Return above 1% (the discount rate used in the model). Results show that larger and more intensive dairy farms, and also herds affected by brucellosis compared with tuberculosis‐positive herds, are more likely to achieve financial gains from the certification investment. The compensation for culled animals is important in the initial phase of herd sanitation and the premium payment on milk would help farmers to achieve a return on the investment over time. The model can be adapted to different and dynamic production, epidemiological and economic settings.     

Does management accounting play role in planning process?

This study examines the relationship between management accounting and planning profiles in Brazilian companies. The main goal is to understand the consequences of not including a fully structured management accounting scheme in the planning process. The authors conducted a field research among medium and large-sized companies, using a probabilistic sample from a population of 2281 companies. Using analytic hierarchy process (AHP) and statistical cluster analysis, the authors grouped the entities' strategic budget planning processes into five profiles, after which the authors applied statistical tests to assess the five clusters. The study concludes that poor or fully implemented strategic and budget-planning processes relate to the management accounting profiles of the Brazilian organizations studied.