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921.
煤矿自燃发火是煤矿重大灾害之一,在开采易自燃煤层时,对煤层自燃发火进行综合防治,对保证煤矿安全生产来说意义重大。本文重点介绍河西采区11171综采工作面采用综合防灭火措施开展自燃防灭火情况。 相似文献
922.
923.
主体功能区划是功能属性更为突出的综合性区域规划,用来规范空间开发秩序,形成合理的空间开发结构。运用指数评价法,选取可利用土地资源、可利用水资源等8个可度量指标,以及调控指标项战略选择,形成覆盖全县域国土空间综合评价的指数,同时对一些重要的参数进行测算,根据反馈结果对区划过程和方案进行优化,划分主体功能类型,提出区划方案。 相似文献
924.
The Prebisch–Singer hypothesis in economics asserts that over time the relative price of primary goods relative to manufactured goods should experience a downward trend. To test the hypothesis, we must first establish the unit root properties of the relative price term and then regress the stationary series on a trend term. We use the quantile unit root test which allows for both smooth unknown numbers and the form of breaks in the trend function through a Fourier function to show that the relative price of 23 out of 24 primary goods is stationary. However, the Prebisch–Singer hypothesis is supported only in half of the primary commodities. 相似文献
925.
生物沼气为生物质能源中最为普及的一种,由于其分散性、小型化和就地取材适合农村发展。文章运用成本——效益函数,通过将农村沼气发展具有代表性地区的实地调研情况与函数的理论前提进行对比分析后发现,发展大中型沼气项目更适合农村实际,从而提出下一阶段农村沼气的发展模式。 相似文献
926.
In this paper, we consider that the working environment has certain states, and in every state, the parameters of quality
characteristics are different. Thus, if we set the characteristics parameters in a specified state, these parameters will
change to another state. To describe this situation, we use a mixture of normal distributions, which comprise a flexible and
powerful statistical-based modeling tool in practice. Under the step loss function and the piecewise linear loss function,
we select the optimal means for the proposed manufacturing process. 相似文献
927.
This paper proposes a multi-prize “reverse” nested lottery contest model, which can be viewed as the “mirror image” of the conventional nested lottery contest of Clark and Riis (1996a). The reverse-lottery contest model determines winners by selecting losers based on contestants’ one-shot effort through a hypothetical sequence of lotteries. We provide a microfoundation for the reverse-lottery contest from a perspective of (simultaneous) noisy performance ranking and establish that the model is underpinned by a unique performance evaluation rule. We further demonstrate that the noisy-ranking model can be interpreted intuitively as a “worst-shot” contest, in which contestants’ performances are evaluated based on their most severe mistakes. The reverse-lottery contest model thus depicts a great variety of widely observed competitive activities of this nature. A handy closed-form solution for a symmetric equilibrium of the reverse-lottery contest is obtained. We show that the winner-take-all principle continues to hold in reverse-lottery contests. Moreover, we find that a reverse-lottery contest elicits more effort than a conventional lottery contest whenever the prizes available to contestants are relatively scarce. 相似文献
928.
This paper discusses the family of life distributions with failure rate functions which decrease initially until a change point and remain constant thereafter. The paper focuses on the estimation for the change point of the failure rate function. While point estimation of the change point of the failure rate function has been discussed by some authors, one can hardly find any existing work on the interval estimation of the change point. In this paper, a method for constructing approximate confidence intervals for the change point is proposed. The proposed approximate confidence intervals are based on the number of failed test items at or before a fixed inspection time. Received: September 1999 相似文献
929.
We consider a supply chain where multiple members are serially connected. The decision is to determine the ordering quantity of a member to the next upstream member in the supply chain. The basic cost model is similar to the newsvendor problem with additional consideration to safety stock. This paper presents optimal approaches for coordination of the supply chain under both complete and partial information sharing in order to maximize the total expected benefit. For complete information sharing we develop an optimal coordination algorithm. For partial information sharing, we propose an optimal coordination algorithm based on the Alternating Direction Method and the Diagonal Quadratic Approximation Method. A numerical example is discussed to show the optimal convergence of ordering quantities and discuss the properties of the proposed algorithms. 相似文献
930.
《Food Policy》2019
Implementation of internationally recommended policy options for obesity prevention has generally been slow and inadequate globally, and, as such, it is important to understand barriers and enablers to policy action in the area. This study aimed to apply political science theories to understand influences on the adoption of Menu Kilojoule Labelling Legislation in Victoria, Australia over the period 2009–2017. Data collection included 13 in-depth semi-structured interviews with participants of the policy development and decision-making processes, analysis of 68 policy documents, and field note observations. Data were analysed using established political science theories: the Advocacy Coalition Framework (ACF) and the Multiple Streams Theory (MST). There were numerous and interrelating factors that influenced the Menu Kilojoule Labelling Legislative policy processes. Barriers to policy reform included electoral turnover, a dominance of neoliberal ideology, and policy maker concerns regarding potential food industry backlash. Key enablers to eventual policy change included the accumulation of evidence on policy effectiveness and feasibility of implementation, increased recognition of the importance of tackling the issue, as well as reductions in political risks achieved, in part, through relatively long consultation and negotiation processes. Findings highlight several tactics that can be used to secure similar policy change in future, including generation, dissemination and translation of implementation evidence, effective mobilisation of supporters, and negotiation and consultation processes that can reduce the degree of opposition to proposed policies. 相似文献