近十年国外旅游推荐系统的应用研究

利用网络进行在线信息搜索已成为旅游者在旅游前获取信息的主要渠道,然而随着互联网的普及发展以及电子商务网站的兴起,旅游者常常被淹没于大量的信息搜索和产品选择当中,而旅游推荐系统则是解决信息超载问题的有效方法。文章通过国外近十年的相关文献的收集整理,对旅游推荐系统的概念、应用及发展现状进行了分析,并重点对旅游推荐系统中的关键技术运用等进行了综述,指出旅游推荐系统应用的复杂性与特殊性,以及在旅游推荐系统中单纯利用基于协同过滤或基于内容过滤的技术的限制性而更多地采用基于知识的及混合的方法;探讨了旅游决策理论在推荐系统中的作用与应用;最后提出了旅游推荐系统的一般模型及未来研究热点,以期对国内旅游推荐系统的研究与应用有所借鉴。     

Assimilation of enterprise technology upgrades: a factor-based study

The purpose of this study is to gain a better understanding of the differences in the propensity of firms to initiate and commit to the assimilation of an enterprise technology upgrade. A research model is proposed that examines the influences that four technological and four organisational factors have on predicting assimilation of a technology upgrade. Results show that firms with a greater propensity to assimilate the new enterprise resource planning (ERP) version have a higher assessment of relative advantage, IS technical competence, and the strategic role of IS relative to those firms with a lower propensity to assimilate a new ERP version.     

Development of a multi-criteria spatial planning support system for growth potential modelling in the Western Cape,South Africa

Growth potential modelling is useful as it provides insight into which settlements in a region are likely to experience growth and which areas are likely to decline. However, growth potential modelling is an ill-structured problem as there is no universally-agreed set of criteria (parameters) that can be combined in a particular way (rules) to provide a definitive growth potential measure (solution). In this paper we address the ill-structured problem of growth potential modelling by combining multi-criteria decision making (MCDM), geographical information systems (GIS) and planning support systems (PPS) to generate a number of growth scenarios for settlements in Western Cape province of South Africa. A new framework and methodology for selecting, structuring and analysing multiple growth potential criteria is proposed. The framework, based on the principles of innovation potential and growth preconditions, was applied to demonstrate how it can be used to identify a series of candidate criteria relating to the growth potential of settlements. The criteria were subjected to a MCDM process involving criteria selection, weighting and normalisation. Two criteria sets, weighting schemes and normalisation methods were considered. Two different classification techniques were also evaluated. A total of 16 scenarios were generated using a newly-developed growth potential PPS (GPPSS). The paper shows how the GPPSS can be used to quantitatively and qualitatively assess the various scenarios and to select the most appropriate solution.     

Truck and trailer scheduling in a real world,dynamic and heterogeneous context

We present a new variant of the Vehicle Routing Problem based on a real industrial scenario. This VRP is dynamic and heavily constrained and uses time-windows, a heterogeneous vehicle fleet and multiple types of job. A constructive solver is developed and tested using dynamic simulation of real-world data from a leading Scottish haulier. Our experiments establish the efficiency and reliability of the method for this problem. Additionally, a methodology for evaluating policy changes through simulation is presented, showing that our technique supports operations and management. We establish that fleet size can be reduced or more jobs handled by the company.     

Organizational patterns of economies: an ecological perspective

A complex adaptive systems paradigm can be used to abridge theorizing in ecological and economic sciences. The paper discusses economic flows, connectivity and stability from the perspective of theoretical ecology. The global economy, by analogy with ecosystems, appears to self-organize as an ascendent system: most of the world trade is done among the tiny fraction of technologically advanced countries and trade interaction strength exhibits a power law with exponential decay. Small world behavior and preferential attachment characterizes interactions among economic agents. Industrial economies and the world economic system as a whole appear to evolve towards the ‘maximum power’ efficiency. Development that fosters efficiency in the maximum power sense (all the world becomes industrialized) implies a trade-off in socio-economic diversity, and may be antithetical to the stability of the global economy. If we take an ecological perspective, then the problem of global development does not reside in the realm of technology or global governance. It boils down to the question of required natural balance in living systems, the balance between organized complexity and overhead, the harmony between efficiency and adaptability.     

Absorption versus direct costing: the relevance of opportunity costs in the management of congested stochastic production systems

This paper investigates the relative performance of absorption versus direct costing procedures. Traditionally, absorption costing procedures have been defended on the basis of them acting as a proxy for hard to measure opportunity costs. We question the validity of this traditional defence by explicitly considering the extent to which absorption costing-based accounting calculations actually provide good proxies. Our analysis shows that in some situations absorption costing so over estimates opportunity costs that it would be preferable to use direct costing even though this implicitly assumes opportunity costs are zero. Thus, given that we establish that one can notalwaysuse the existence of opportunity costs as a defence for the adoption of absorption costing procedures we next identifyspecificconditions for which if satisfied, we can unambiguously defend the adoption of absorption costing. We develop an ‘open acceptance condition’ which if satisfied insures that a production system directed by absorption costs out performs a system based upon direct costs.     

Fractal structures and naive trading systems: Evidence from the spot US dollar/Japanese yen

This study investigates whether daily logarithmic returns on the spot US dollar/Japanese yen (USD/Yen) for the period 3 March 1987 to 8 September 1993 displayed an underlying fractal structure. The analysis employed a rescaled range (R/S) technique, and revealed USD/Yen persistence which favoured continued depreciation of the USD. The results suggest the presence of time or memory effects in the currency. These effects were arbitrageable by speculators who by holding long Yen positions were able to earn positive returns.     

The Impacts of Changes in Key Economic Variables on Crop Rotational Choices on Ontario Cash-Cropping Farms

This study is a sequel to one providing a methodological framework for evaluating the economic and soil-erosion effects associated with different crop rotational systems involving corn on southern Ontario cash-cropping farms. A multi-period linear programming (MPLP) model is used to estimate the impact on rational crop rotational choices, fam-level profitability and soil-erosion rates of having different values for the more important economic variables. The variables examined are relative cash-crop prices, fossil fuel energy-related production costs, discount rates, and values attached to soil lost through erosion. The MPLP model is solved in turn for each of a range of values for one of the economic variables at a time, the selection of values being based upon recent historical experience. Where no change in rotational system is prompted within the range, the MPLP model is used to find the value of each economic variable that would be required to trigger the choice of some alternative rotational system. Each of these model runs is performed for the case where yields of all crops over a 20-year time horizon are firstly assumed constant, and secondly assumed to suffer a cumulative decline. Cet article fait suite à une étude méthodologique dont le but a été d'valuer les effets économiques et érosifs de systémes de production produisant essentiellement du maïs en rotation avec d'autres cultures. Cette méthode d'analyse est appliquée à des exploitations agricoles localisées dans le Sud de I'Ontario et specialisées dans les cultures commerciales. Pour ce faire, un modéle linéaire multi-période (MPLP) est utilisé pour estimer I'impact d'un changement dans les principales variables économiques sur le choix des rotations culturales, le niveau de rentabilité des systémes de production et les taux d'érosion des sols. Les variables économiques prises en compte sont les prix relatifs des cultures commerciales, les coûts de production associés à la consommation d'énergie fossile, les taux d'actualisation et les pertes absolues en sol dues à l'érosion. Le modéle linéaire (MPLP) est de nouveaurésolu pour chaque variable économique en les paramétrisant sur un intervalle de valeurs selectionnées à partir de donntes historiques récentes. Lorsqu'il n'y a aucun changement dans la rotation culturale, le modéle détermine le niveau de chaque variable qui entrainerait la prise en considération d'une rotation culturale alternative. Toutes les simulations ont été effectuées sur une période de vingt ans en adoptant deux variantes sur I'tvolution des ren-dements des cultures commerciales: premierèment, les rendements restent constants durant toute la période, et deuxiémement, les rendements décroissent de maniére cumulative.     

Cost reductions or reputation enhancement as motives for mergers: The logic of multihospital systems

This paper examines two motives for the formation of local multihospital systems: cost reduction and reputation enhancement. Systems may reduce costs by eliminating redundancies and reducing administrative costs. Integration may also lower costs for consumers seeking consistently high qualiiy. We hypothesize that if systems achieve either cost or reputation benefits, then member hospitals will ‘look’ different from random collections of hospitals. We find that local systems do not appear to have lower costs but do appear to enjoy reputation benefits over nonsystem hospitals. Our findings challenge the assumptions behind popular health reform initiatives.     

The baggage system at Denver: prospects and lessons

This article discusses the fundamental design difficulties of the fully automated baggage system originally planned for the New Denver Airport, and their implications for airport and airline management. Theory, industrial experience, and the reality at Denver emphasize the difficulty of achieving acceptable standards of performance when novel, complex systems are operating near capacity. United Airlines will thus make the Denver system ‘work’ by drastically reducing its complexity and performance. Automated baggage systems are risky. Airlines and airports considering their use should assess their design cautiously and far in advance, and install redundant, supplemental systems from the start.