The response of U.S. natural gas futures and spot prices to storage change surprises: Fundamental information and the effect of escalating physical gas production

We study the behavior of U.S. natural gas futures and spot prices on and around the weekly announcements by the U.S. Energy Information Administration of the amount of natural gas in storage. We identify an inverse empirical relation between changes in futures prices and surprises in the change in natural gas in storage and that this relation is not driven by the absolute size of the surprise. The evidence also indicates prices react first in the futures market for natural gas with that information then flowing to the spot market. Post 2005, corresponding to a period of significant increases in the production of natural gas in the United States, the response of prices to storage surprises was larger in absolute value. No evidence is found of economically meaningful reactions to the surprise other than on the date the storage news is released. The results demonstrate the importance of fundamental information in the formation of natural gas prices.     

Implications of domestic price insulation for global food price behavior

Rapid changes in global food prices in recent years are widely viewed as a serious threat to global development. While various sources of price instability in agriculture have been identified, little attention appears to have been given to the importance of changes in trade policies that insulate domestic prices from world markets as a source of volatility in world prices. A contribution of this paper is to show that these interventions are dynamically more complex than simple proportional insulation. Insulation against an initial price increase in world prices increases the magnitude of that increase, while subsequent adjustments to the level of protection change the fundamental nature of price volatility. We find such policies are widespread and increase the volatility of world prices while not reducing the volatility of domestic prices because of the collective action problem involved in this form of policy intervention.     

《药品储存与养护》教学改革与实践

目的:为培养适合企业发展需求的新型药品储存与养护人员提供参考。方法:通过调查研究了解企业需求、分析岗位职业能力要求,确定教学目标;以药品保管员、养护员岗位职业能力培养为核心,构建课程教学模块、探索有效的教学方法及合理的教学效果评价方法。结果与结论:明确了新时期企业对药品保管员、养护员的要求并确立了课程教学目标,构建出以岗位职业能力培养为核心的教学模块,摸索出适应职业能力形成的有效教学方法及全面、客观、合理的教学效果评价标准与方法,为培养适合企业发展要求的新型药品保管员与养护员提供有益的参考。     

基于ArcSDE和SQL Server 2005的城乡动态监测集成数据库的构建——以义乌市城乡动态监测集成数据库为例

海量城乡动态监测数据的组织和管理是城乡动态监测亟待解决的问题。本文以义乌市城乡动态监测集成数据库为例,在对城乡动态监测集成数据库特点进行深入分析的基础上,介绍了基于ArcSDE和SQL Server 2005的城乡动态监测集成数据库设计及构建流程,并对城乡动态监测数据分类与编码、数据库逻辑设计及数据库存储设计进行了详细阐述。     

Impact of metal silos on households’ maize storage,storage losses and food security: An application of a propensity score matching

Maize is the most important food staple in Eastern and Southern Africa, with a highly seasonal production but relatively constant consumption over the year. Farmers have to store maize to bridge seasons, for food security and to protect against price fluctuations. However, the traditional storage methods do not protect grain well, resulting in large postharvest losses. Hermetically sealed metal silos kill storage pests by oxygen deprivation without pesticides. Popular in Central America, they are now being promoted in Africa, but their impact here has not yet been studied. This study used propensity score matching to evaluate the impact of metal silos on duration of maize storage, loss abatement, cost of storage, and household food security. Metal silo adopters (N = 116) were matched with non-adopting farmers from a representative sample of 1340 households covering the major maize-growing zones in Kenya. The major effect of the metal silos was an almost complete elimination of losses due to insect pests, saving farmers an average of 150–200 kg of grain, worth KSh9750 (US$130). Metal silo adopters also spent about KSh340 less on storage insecticides. Adopters were able to store their maize for 1.8–2.4 months longer, and to sell their surplus after five months at good prices, instead of having to sell right after the harvest. The period of inadequate food provision among adopters was reduced by more than one month. We conclude that metal silos are effective in reducing grain losses due to maize-storage insects, and that they have a large impact on the welfare and food security of farm households. The initial cost of metal silos is high (KSh20,000/1.8 ton) and therefore policies to increase access to credit, to reduce the cost of sheet metal, and to promote collective action can improve their uptake by smallholder farmers.     

New batch construction heuristics to optimise the performance of order picking systems

Two new batch construction heuristics called K-means Batching (KMB) and Self-organisation Map Batching (SOMB) are developed and verified by simulation experiments. Both KMB and SOMB have a preferment of superior performance in total travel distance and average picking vehicle utility, and even a conspicuous improvement in total CPU running time. Besides, this paper investigates the overall performance of order picking systems integrating storage assignment, order batching and picker routing to find the optimal policy combinations under different order types. The sensitivity analysis is performed to distinguish the relative importance of the various strategies to enhance the performance of operations management.     

云存储网盘综合性能评定

网盘是网络与存储技术结合的产物,已成为企业和个人存储和共享信息资源的重要工具,云存储技术的应用与无线网络的普及,为网盘发展带来了新前景。目前,国内外网盘品牌颇多且各具特色,本文选择国内现流行的五款产品,运用层次分析法评定其综合性能,发现高传输速度为网盘商带来竞争优势。     

基于ESCP范式下的我国新能源储能产业发展战略研究

在分析我国新能源储能产业发展现状的基础上,试图从产业环境和政府政策角度出发,改进并运用SCP框架,对当前我国新能源储能产业环境、市场结构、运营商策略行为、市场绩效以及储能产业政策进行综合分析。分析表明,目前我国新能源储能产业虽取得了一定的发展,但仍存在的国家重视力度不够、产业集中度过高、进入壁垒大、投资回报机制不健全技术人才缺乏、科技创新资金投入不足及产业规模偏小等问题,因此只有发现发展过程中所存在的问题,才能为储能产业的高效、健康、持续发展提供相关建议并制定出我国新能源储能产业发展战略。     

iSDS: a self-configurable software-defined storage system for enterprise

ABSTRACT

Storage is one of the most important aspects of IT infrastructure for various enterprises. But, enterprises are interested in more than just data storage; they are interested in such things as more reliable data protection, higher performance and reduced resource consumption. Traditional enterprise-grade storage satisfies these requirements at high cost. It is because traditional enterprise-grade storage is usually designed and constructed by customised field-programmable gate array to achieve high-end functionality. However, in this ever-changing environment, enterprises request storage with more flexible deployment and at lower cost. Moreover, the rise of new application fields, such as social media, big data, video streaming service etc., makes operational tasks for administrators more complex. In this article, a new storage system called intelligent software-defined storage (iSDS), based on software-defined storage, is described. More specifically, this approach advocates using software to replace features provided by traditional customised chips. To alleviate the management burden, it also advocates applying machine learning to automatically configure storage to meet dynamic requirements of workloads running on storage. This article focuses on the analysis feature of iSDS cluster by detailing its architecture and design.     

中国粮食仓储的历史与展望

粮食仓储作为中国历史发展中的重要载体,对于社会的繁荣、稳定和发展具有重要意义。本文主要论述了中国古代和现代粮食仓储的发展历史及其价值,并对粮食仓储未来的发展进行展望。