Meat and fish consumption patterns in Saudi Arabia

This study analyses the demand for meat (beef, chicken and lamb) and fish in Saudi Arabia in a system-wide framework using data for the period 1985–2010. A preliminary data analysis reveals that, in Saudi Arabia, the relative consumption of beef, chicken and fish has a positive growth, while lamb has a negative growth. The average relative price growth rates of beef, chicken and fish are negative, while that of lamb is positive. The expenditure shares of beef, chicken and fish have increased while that of lamb has fallen. The estimation results of the demand system reveal that there is an autonomous trend out of lamb into beef, chicken and fish. The implied income elasticities indicate that beef, lamb and fish are considered to be luxuries, while chicken is a necessity. The demand for all meat products and fish are price inelastic. These elasticities are key inputs for policy analysts in terms of devising policies in relation to meat production, meat imports, taxation and food security issues in Saudi Arabia. The usefulness of the implied elasticities is demonstrated by simulating the consumption of beef, chicken, lamb and fish under various policy scenarios.     

Towards proactive airport security management: Supporting decision making through systematic threat scenario assessment

An airport is the gateway which facilitates access to air transport. As a reaction to very diverse attacks on the air transport system during the last decades a broad range of security measures has been introduced to mitigate possible threats. The challenge to provide a trouble free experience for the passenger and, at the same time, to operate more efficiently calls for a proactive approach. This requires the definition of future requirements that allow an adaptation of the security system. When dealing with uncertainty that future-oriented decisions inevitably display, it is important to gain as much knowledge as possible about a system's general structure. The approach described in this paper systematically documents elements and relationships of the airport security system. It consists of threat scenario elements as well as security measures. The development of a software tool, the so-called Scenario Builder, is described and its application for the identification of possible future threats explained. The presented approach offers intuitive access to the underlying structure of the airport security system. It provides decision makers with a possibility to interact with the system and anticipate effects of threat development, thereby enabling robust, future-oriented decisions.     

Energy futures: Diversity and the need for assessment

In energy policy and energy research, decisions have to be made about the technologies and infrastructures that may be used to provide and distribute energy in future times, some of which are very distant. Frequently, energy futures such as predictions of the energy demand or energy scenarios are used for decision-support in this field. The diversity of energy futures, however, threatens any possibility for orientation, could lead to disorientation instead of helping more rational decision-making and could be used for ideological purpose. In this paper, we investigate concepts and approaches for scrutinizing, comparing and assessing the various energy futures from an epistemological point of view. Following the analysis of the structure of (energy) futures we will conclude that comparisons and assessments of energy futures should be made through processes of scrutiny and assessment, looking into the ingredients which have been used in constructing the respective futures, and into the process of their composition. Providing much more insight into the cognitive and normative structure of energy futures is required for allowing a more transparent and deliberative societal debate about future energy systems.     

Governing the transition to low-carbon futures: A critical survey of energy scenarios for 2050

There is a growing scientific consensus that limiting the increase in global average temperature to around 2 °C above pre-industrial levels is necessary to avoid unacceptable impact on the climate system. This requires that the developed countries’ emissions are radically reduced during the next 40 years. Energy scenario studies provide insights on the societal transitions that might be implied by such low-carbon futures, and in this paper we discuss how a greater attention to different governance and institutional issues can complement future scenario exercises. The analysis is based on a critical review of 20 quantitative and qualitative scenario studies, all of relevance for meeting long-term climate policy objectives. The paper: (a) analyzes some key differences in energy technology mixes and primary energy use patterns across these studies; (b) briefly explores the extent and the nature of the societal challenges and policy responses implied; and (c) discusses a number of important implications for the design and scope of future scenario studies. Our review shows that in previous scenario studies the main attention is typically paid to analyzing the impact of well-defined and uniform policy instruments, while fewer studies factor in the role of institutional change in achieving different energy futures. We therefore point towards a number of strategies of integrating issues of transition governance into future scenario analyses, and argue for a closer synthesis of qualitative and quantitative scenario building.     

多隔间车辆路径问题研究综述

随着不能混装货物需要同时进行配送要求的出现,以及现代物流中待运产品多样性特征的产生,多隔间车辆路径问题(MCVRP)于近年来逐渐受到关注。文章首先归纳了多隔间车辆路径问题的应用场景,并阐述了每种场景下使用多隔间车辆运输不相容货物的优点。然后,根据问题特征,对多隔间车辆路径问题研究进行归纳分类并就每类研究问题分别予以综述。最后,针对多隔间车辆路径问题在当前形势下面临的新挑战进行展望,并提出五个新的研究方向。     

Guest Editorial

Abstract

While some Internet-only retailers survive and prosper, for most, multichannel retailing provides a sustainable and attractive blend of new and existing retail formats. The complementary roles of stores and Internet are frequently noted, yet the renewed significance of catalogues is often ignored. This paper is based upon a survey of 2,341 shoppers across three product sectors and three shopping scenarios, identifying their relative utilization of, and attitudes towards, stores, catalogues and the Internet.

Principal component analysis and multi-attribute analysis (MAA) scores summarize attitudes across the three channels, sectors and motivational scenarios. Four major components in channel choice emerge consistently: risk reduction, product value, ease of shopping and experiential. K-Means clustering on preference and behavioural variables identifies the truly multichannel shopper segment. Key characteristics of these shoppers are summarized, demonstrating that the multichannel shopper comprises a large and mainstream segment. Implications are identified for retailers and researchers.     

Improving Electricity Market Price Forecasting with Factor Models for the Optimal Generation Bid

In liberalized electricity markets, the electricity generation companies usually manage their production by developing hourly bids that are sent to the day‐ahead market. As the prices at which the energy will be purchased are unknown until the end of the bidding process, forecasting of spot prices has become an essential element in electricity management strategies. In this article, we apply forecasting factor models to the market framework in Spain and Portugal and study their performance. Although their goodness of fit is similar to that of autoregressive integrated moving average models, they are easier to implement. The second part of the paper uses the spot‐price forecasting model to generate inputs for a stochastic programming model, which is then used to determine the company's optimal generation bid. The resulting optimal bidding curves are presented and analyzed in the context of the Iberian day‐ahead electricity market.     

基于工作过程的“企业所得税报税实务”课程开发与探究

企业所得税是税收实务教学中的难点,企业所得税的会计核算及纳税申报又是实务操作中的难点,基于工作过程系统化的职业课程设计理念,我们开发了＂企业所得税报税实务＂课程,本文论述了该课程的开发背景、课程设计、教学实施以及考核评价等内容。     

Convergence of Romanian and Europe Union agriculture – evolution and prospective assessment

This paper presents forecasts related to the evolution of agricultural production in Romania, relative to the European Union average and to other countries (France, Germany, and Hungary) while taking into consideration the production potential of Romanian agriculture and opportunities to mobilize certain additional financial sources intended for the growth of intermediate consumption and implicitly of the value of agricultural production. This undertaking is designed to identify the degree to which over the next 20 years, Romania can come closer to agricultural performance, standard of living and food quality levels of developed European countries. Current disparities are significant, and there is no promise that they will be eliminated or at least not for all indicators, as structural problems related to Romanian agriculture at this time can be addressed only over the long term. We use historical data drawn from national and international statistical databases and forecast of their evolution using power regression functions. For French, German, Hungarian and European Union-27 average values, the historical growth rate has been preserved, and we develop three scenarios (pessimistic, realistic and optimistic) for Romania based on annual growth rates of 3%, 3.5% and 4%. On the basis of these work assumptions, we forecast agricultural production value, gross added value and intermediate consumption per hectare of agricultural area utilized. From these indicators we find that by maintaining the same historical development rate for all countries, Romania cannot reach the average European Union-27 level or levels for the other countries studied (France, Germany and Hungary) until 2038. A realistic scenario that takes into account an annual growth rate of 3.5% would allow for the elimination of disparities while taking into account a new evolutionary perspective on agricultural production with new production structures based on the following factors: amalgamation of land, expansion of irrigated surfaces, growth of animal production shares, development of agricultural research, expansion of financing opportunities.