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1.
发电设备利用小时数变化的影响因素及变化趋势分析   总被引:5,自引:4,他引:1  
从1978-2008年我国发电设备利用小时数的统计数据,分析影响发电设备利用小时数的主要因素,认为发电设备利用小时数与GDP、发电装机增速等因素相关。对于我国发电小时数变动趋势、影响因素以及国际比较等方面的特点与规律进行了解析,并对规避投资风险、提高电力行业效率提出了建议。  相似文献   

2.
In most of the papers on inventory models operating in a random environment, the state of the environment in each period is assumed to be fully observed with perfect information. However, this assumption is not realistic in most real-life situations and we provide a remedy in this paper by assuming that the environment is only partially observed with imperfect information. We accomplish this by analyzing two formulations of single-item models with periodic-review and random supply in a random environment. In the first one, supply is random due to random capacity of production and random availability of transportation. We show that state-dependent base-stock policy is optimal if the capacity and all costs are observed, while demand and availability are unobserved. In the second model, we consider a model with random availability only with fixed-ordering cost. We show that state-dependent (s,S) policy is optimal if the availability process is observable.  相似文献   

3.
We use a county-level panel dataset from 2012 to 2018 to assess the impacts of various state policies on total and rural broadband availability in the United States. The primary dependent variable is the percentage of residents with access to 25 Megabits per second (MBPS) download and 3 MBPS upload speeds via a fixed connection, with alternative specifications considering other aspects of availability such as technology type and competition. We control for the main determinants of Internet availability such as income, education, age, and population density. Our policy variables come from the newly released State Broadband Policy Explorer from the Pew Charitable Trusts and individual contacts from the nationwide State Broadband Leaders Network. Our primary policies of interest are those related to: (1) availability of state-level funding, (2) existence of a state-level broadband office/task force with full-time employees, and (3) restrictions on municipal/cooperative broadband provision. We find a positive and significant impact of state-level funding programs on general (and fiber) broadband availability, and a negative impact of municipal/cooperative restrictions. The findings are similar when the analysis is restricted to the rural portions of counties.  相似文献   

4.
State and local governments have enacted different types of legislation aimed at improving broadband availability. Two unstudied policies of interest are: (1) “dig-once” policies requiring state-funded construction projects to notify local internet providers about the opportunity to bury conduit for easier wire installation in the future, and (2) permitting policies requiring an expeditious response from local jurisdictions regarding the installation of broadband equipment. We use the example of Iowa, which passed legislation on both of these topics in 2015 and compare trends in fiber broadband availability with that of states who did not pass such legislation. We also consider the potential impact on fixed wireless availability, which largely depends upon a fiber middle mile. We use coarsened exact matching at the census tract level to construct treated and control groups with similar pre-2015 demographic characteristics and broadband availability trends in Iowa and other states. Difference-in-difference regression analysis with the matched samples then assesses the policy impact on fiber and fixed wireless availability post-implementation. The results suggest that Iowa's policies increased fiber broadband availability by 2.4%–6.6% when considering eight model specifications which account for different criteria such as geographic region, other (non-dig-once or permitting) broadband policies, and federal funding received. The policies do not appear to have any effect on fixed wireless availability.  相似文献   

5.
6.
In addition to volatile fluctuations due to seasonal or regional factors, food security has two main components; access and availability. This paper presents a diagrammatical model to indicate how aquaculture, particularly private sector aquaculture, can contribute to these components of food security in sub-Sahara Africa. Food accessibility is increased when commercial aquaculture generates employment. Without such employment the poor might never translate their need for food into effective demand. Food availability is increased, either immediately when aquaculture output is sold in the domestic market, or later when the foreign exchange earned from aquaculture exports is used to import food.  相似文献   

7.
This paper estimates the effect of the expansion of broadband infrastructure, which enables high-speed Internet, on population development in panel of Finnish areas in the period 2010–2018. The study differs from previous studies in that it uses accurate statistics on the availability of broadband in 1 km * 1 km population grids. Therefore, the impact of broadband availability on rural development is evaluated more accurately than previously. The results of the Difference-in-difference (DiD) regression analysis show that the availability of broadband reduces depopulation of remote and sparsely populated rural areas. In this respect, the telecommunication policy in Finland has been successful, and the findings encourage the expansion of broadband infrastructure in rural areas.  相似文献   

8.
This paper tests the targeting efficacy of multilateral food aid at the level of nation states, exploring whether it stabilizes food availability in recipient economies, flows most to those with the greatest need, or both. We find that, unlike bilateral flows from the United States under PL 480, multilateral food aid distribution by the World Food Programme flows countercyclically, thereby stabilizing food availability in recipient economies. WFP flows also exhibit significant progressivity at the regional level, helping to resolve international inequalities in food availability per capita.  相似文献   

9.
A vision of improved telecommunications infrastructure leading to dramatic improvements in the economies and the quality of life in developing countries is now supported by an increasing body of evidence. Economic justification of the necessary investment depends on the availability of appropriate low cost technology, such as microprocessor-based digital satellite earth stations costing under $10000. Such technology is technically feasible, but its availability will depend on the emergence of a consensus among telecommunications lenders, borrowers and manufacturers that the benefits can be achieved and therefore the necessary mass market will emerge.  相似文献   

10.
风力发电机组性能考核方法探讨   总被引:2,自引:1,他引:1  
张瑞君 《电力技术经济》2011,23(11):70-72,77
功率曲线和可利用率2项指标可在总体上表征风电机组的经济和技术性能。通过对风电机组功率曲线和可利用率计算方法的分析,提出了一套实用性较强的风电机纽性能考核办法,以期为风电机组运行效果评价提供理论依据。  相似文献   

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