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by Dilip Kumar Bhattacharya
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The paper discusses an economically viable way of controlling biomass of a vegetable plant population under the use of fertilizer in a given span of time under a given budget of expenditure. The span of time is divided in some suitable consecutive periods of equal duration P, called cohorts. The treatment is done on the available population of plant at the beginning of each cohort for a suitable time; the continuous dynamics in the change of biomass for this time period is governed by an ordinary differential equation involving total effort exerted in treating the initial population. Taking this improved value at the end of the time period as the initial value, the biomass of the population is allowed to move under its normal continuous dynamics given by Logistic growth equation for the rest of the time of that cohort.  The final concentration of the biomass at the end of the first cohort is obtained by following the above two types of dynamics. This is also considered as the starting biomass for the next cohort. The same process adopted for the first cohort is repeated for calculating the improvement of the biomass in the second cohort and the whole process is repeated till the end of the final cohort is reached. Next an objective function is formed for the given span of time. This measures the net profit in getting improvement in the weight of the biomass less the cost involved in the process of improving the weight of the biomass for the given period of time. As the analysis is done in considering different cohorts at regular intervals of time, so it is a discrete model. As within each cohort, the dynamics takes place continuously, so it is a continuous model too. As a whole, the model is found to be a continuous- discrete model. Hence method of optimal control for continuous-discrete model is used to determine how the treatment at the starting of each cohort be adjusted, depending on the allocated budget, so that the total net profit is maximum.
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by Sofia Bartolomeu, Madalena S. Malhadas, João Ribeiro, Paulo C. Leitão, João M. Dias
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The South China Sea region, and particularly the Malacca and Singapore Straits, are known by the complex tidal dynamics, which is influenced by the tidal propagation from Pacific and Indian Oceans. In spite of the dynamic complexity, the region is very relevant economically, especially concerning the growing oil drilling activities. To give support to accidental oil spill prevention and response, an operational oil spill forecast system was developed for the Strait of Malacca. The hydrodynamic system validation revealed good results, in general. However, besides all the modeling efforts, some discrepancies between observed and predicted sea levels were identified, mainly during neap tide and for specific tide-gauges. Therefore, the main aim of this study consists in researching the origin of these discrepancies by comparing predictions with available data and exploring their relation with the MeteOcean processes of the region. Initially sea level data for eight tide gauges was explored to get a general overview of the local tidal dynamics, and then the model performance for astronomic tide was assessed. Analysis of meteorological tides was also performed for three tide-gauges located in the Singapore and Malacca Strait, which are under the influence of the northeast or southwest monsoons. The results show that the differences between the observed and predicted sea levels in Singapore Strait are usually due to discrepancies in the meteorological tide induced by the surface wind stress acting over the Taiwan-Singapore axis, while in the Malacca Strait are mainly related with model limitations in reproducing the astronomical tide.
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Articles

by V.M. Markova, Victor Churashev
54 Views, 0 PDF Downloads

It is shown that topical issue is the solution of problems of enhancement of structure electro and heat generations in regions of Russia, including through synchronization of schemes electro and heat supplies. It causes the necessity of integration to municipal level power engineering into development plans for big power industry that causes gain of a role of the distributed power engineering (including the cogeneration installations). The carried-out serial calculations for comparative assessment of a row of technologies of the small-scale distributed power generation in the Novosibirsk and Kemerovo regions allowed to select the perspective directions of diversification of energetic branch. 

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by Jingyi Yan, Xiyao Zhong, Wenming YAN
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In the process of promoting modern hospital management system, the two basic issues repeatedly thought and constantly researched are: what kind of modern hospital management system will be established and how to establish modern hospital management system. Seen from current status, modern hospital management system is arranged by public hospital system making modern hospital and management system match socialist market economic system, meanwhile, modern hospital management mode is also the target mode Chinese public hospitals constantly reform. Three comparatively outstanding features and requirements of modern hospital management are systematic power release, effective governance and scientific management. The features can be specified, that is to say, in the aspect of organization form, modern hospital management system belongs to one special public legal person system, power release of systematism is made by this system; From the aspect of system equipment, modern hospital management system includes one series of interrelated governance mechanism to conduct effective governance; From the aspect of management behavior, modern hospital management system means scientific, refined and professional management of public hospitals to realize the feature of scientific management. 

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by Yanhong Zhao
47 Views, 0 PDF Downloads

 In the business process of each enterprise, logistics management plays a vital role which directly affects the economic strength of the enterprise.With the continuous development of the market economy in China, the effective control of the logistics links can improve the economic and market competitiveness of the enterprises to a certain extent. According to the current status of enterprise logistics management, the article studies the problem existing in logistics management and puts forward effective solutions to the problems.

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