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61.
Jon M. Conrad 《Journal of Bioeconomics》1999,1(2):205-217
Consider an offshore fishing grounds of size K. Suppose the grounds has been overfished to the point that net revenue has been driven to zero and the fishery is in open access equilibrium at (X, Y). A marine sanctuary, where fishing is prohibited, is then created. Suppose the marine sanctuary is of size K2 and that fishing is allowed on a smaller grounds, now of size K1, where K1 + K2 = K. In the first, deterministic, model, the present value of net revenue from the grounds-sanctuary system is maximized subject to migration (diffusion) of fish from the sanctuary to the grounds. The size of the sanctuary is varied, the system is re-optimized, and the populations levels, harvest, and value of the fishery is compared to the 'no-sanctuary' optimum, and the open access equilibrium. In the deterministic model, a marine sanctuary reduces the present value of the fishery relative to the 'ideal' of optimal management of the original grounds. In the second model net growth is subject to stochastic fluctuation. Simulation demonstrates the ability of a marine sanctuary to reduce the variation in biomass on the fishing grounds. Variance reduction in fishable biomass is examined for different-sized sanctuaries when net growth on the grounds and in the sanctuary fluctuate independently and when they are perfectly correlated. For the stochastic model of this paper, sanctuaries ranging in size from 60 to 40% of the original grounds (0.6 K2/K 0.4) had the ability to lower variation in fishable biomass compared to the no sanctuary case. For a sanctuary equal to or greater than 70% of the original grounds (K2 0.7K), net revenue would be nonpositive and there would be no incentive to fish. 相似文献
62.
This paper explores the relationship between concentration, output and trade usingtheory and empirical analysis of matched data on 82 manufacturing industries in seven countries. It finds that the higher is domestic concentration in an industry compared to international concentration, the lower is the domestic share of world output and thesmaller are net exports. This relationship persists even when industries with high levelsof concentration are excluded. 相似文献
63.
以山东滨化集团热力公司二期项目锅炉补给水二期2x100t/h反渗透扩建工程为背景,结合锅炉补给水处理的主要工艺方案特征,基于招标博弈为前提,分析了电厂水处理系统方案优化的新途径。 相似文献
64.
65.
芳烃联合装置的设计优化 总被引:2,自引:0,他引:2
曹坚 《石油化工技术经济》2004,20(6):17-22
以某石化公司拟新建的450kt/a对二甲苯芳烃联合装置为个案,从技术和经济评价两方面对几个不同处理量的工艺装置的组合方案进行了设计计算,探讨了利用富含芳烃的乙烯裂解汽油作为芳烃原料的可行性和优越性。 相似文献
66.
Zeus Guevara Edmundo Molina-Pérez Edith X. M. García Vanessa Pérez-Cirera 《Economic Systems Research》2019,31(2):178-205
The North-America Free Trade Agreement (NAFTA) has brought together the economies of Canada, Mexico, and the US into forming one of the largest trading blocs worldwide (within the top CO2 emitters). However, the current global protectionist discourse threatens the agreement. This paper analyzes the energy and energy-related CO2 emission relationships between NAFTA countries in 2014 to gain insights into the climate change implications of current integration and the possible cancelation of the agreement. The analysis is performed with a multi-regional version of the multi-factor energy input–output model. The results show that NAFTA has not built a single integrated energy system, though it has helped reduce energy-related CO2 emissions. Moreover, if NAFTA is not revoked, further integration would depend on the capacity of the Mexican energy sector to converge to the performance of its trade partners’ energy sectors. Conversely, a broken deal would induce negative environmental externalities. 相似文献
67.
68.
Beatriz Junquera Jesús Ángel del Brío 《Technology Analysis & Strategic Management》2017,29(10):1139-1152
This paper aims to thoroughly look into the effects of the differences between the diverse leadership styles on innovative outputs (intensive, efficient and eco-efficient) in Spanish industrial companies. A questionnaire for the factories was sent and was received between the months of September 2013 and June 2014. A total of 142 valid questionnaires were received. Several regression models were used in the empirical analysis. The results show that charismatic leadership positively induces an intensive innovative output, at the same time as it improves firms’ eco-efficient innovative output. Likewise, the individualised consideration that characterises transformational leadership makes this leadership style produce positive results on the whole group of innovative outputs considered. At the other end of the leadership spectrum, the transactional style causes negative effects on the relationship between innovative activity and innovative outputs, and more specifically, on the efficient innovative output. 相似文献
69.
为了降低制造业的生产成本,提高收益,在分析生产物流配线闲置和超载成本的基础上,采用粒子群算法对其进行优化,并利用模糊自适应改进惯性权值,通过实证研究表明该方法实用,可操作性强,可以有效降低制造业生产物流成本,具有广泛的应用价值。 相似文献
70.
系统建立了三维仿真框架,建立了三维空间属性模型和非空间属性模型,分别对空间数据和非空间数据进行储存和管理。并建立了Hardy-Cross迭代模型和离散反馈型神经网络模型优化通风网络模型。并以C#语言来实现系统的功能。 相似文献