基于复杂网络的产业核心技术识别预测研究——以能源产业为例

摘?要：立足情报研究视角,探索建立科学完整的科技文献信息挖掘及核心技术识别预测方法体系,揭示战略前沿领域的核心技术,明确核心技术的重点研发方向和潜在研发趋势。在界定核心技术概念及类型的基础上,利用文献知识聚类识别热点技术,通过RAKE算法抽取技术主要研究内容,以各项热点技术为节点构建复杂网络,通过节点二次聚类和可视化方法展现技术结构网络,采用结构洞理论分析网络和节点特性,从中遴选出关键技术;利用复杂网络链路预测算法,预测技术结构网络中的缺失边产生连接的可能性,判断现有热点技术未来的交叉融合,以此识别潜在新兴技术。以能源产业为例开展实践,对该领域的科技文献开展深入挖掘,揭示领域核心技术,初步验证了方法的可操作性和有效性。     

Assessing the impact of communication costs on international trade

Communication costs are frequently cited as an important determinant of trade costs. We test this relationship by incorporating alternative measures of communication costs in a model of bilateral trade. We find that international variations in communication costs indeed have a significant influence on trade patterns. Furthermore, estimates using disaggregated data reveal that communication costs are more important for trade in differentiated products than for trade in homogenous products.     

Hedging nontradable risks with transaction costs and price impact

A risk‐averse agent hedges her exposure to a nontradable risk factor U using a correlated traded asset S and accounts for the impact of her trades on both factors. The effect of the agent's trades on U is referred to as cross‐impact. By solving the agent's stochastic control problem, we obtain a closed‐form expression for the optimal strategy when the agent holds a linear position in U. When the exposure to the nontradable risk factor is nonlinear, we provide an approximation to the optimal strategy in closed‐form, and prove that the value function is correctly approximated by this strategy when cross‐impact and risk‐aversion are small. We further prove that when is nonlinear, the approximate optimal strategy can be written in terms of the optimal strategy for a linear exposure with the size of the position changing dynamically according to the exposure's “Delta” under a particular probability measure.     

The impact of transport costs on new venture internationalisation

This paper investigates the importance of transport costs in new venture internationalisation, i.e. of firms that start exporting before they are 3 years of age. It does so by merging two large international datasets, on the firm level (covering 49,584 firms) as well as on the country level (covering 154 countries). It is found that transport costs matter significantly for new venture internationalisation, for older firms’ decision to export, as well as the extent of the latter’s subsequent exports. Export costs, the quality of transport infrastructure and domestic logistics costs affect new venture internationalisation even when controlling for a range of standard determinants. New international ventures behave differently from older firms in two important ways: (1) Transport costs affect the probability that they will export but not the extent of their subsequent exports and (2) their probability of exporting is affected negatively by their networking, domestic success and ISO status, whilst in the case of older firms, these factors have a positive impact. Various recommendations for policy and further research are made.     

The impact of risk perceptions on the attitude toward multi-channel technologies

ABSTRACT

Several studies show that retailers experience favorable outcomes if consumers use multiple channels. Thus, retailers aim to encourage consumers to do so in a convenient way by offering multi-channel technologies (MCTs). However, not much is known about what affects a positive attitude toward such technologies. Our study investigates how different risk perceptions influence the attitude toward specific MCTs in comparison (check and reserve, click and collect, availability check). Moreover, we examine whether the customer’s general purchase channel preference moderates these effects. Results show that three risk dimensions have significant impacts on the attitude toward MCTs. These effects are generally worst for click and collect, as the negative effects (product quality and data risk) are highest, while the positive effect (product availability risk) is lowest, compared to the other two MCTs. Additionally, we generally find that the more a customer prefers buying via the online channel, the weaker the effects of the risk dimensions on the attitude are. Our findings provide implications on how to improve consumers’ attitudes toward the selected MCTs by influencing their perceptions of different risk dimensions.     

从生物学角度认识中国出生缺陷

出生缺陷严重影响出生人口素质,成为我国重大公共卫生问题.遗传因素、环境因素,以及二者的相互作用是导致出生缺陷发生的直接原因.以神经管畸形为例,分别从遗传易感性、表观遗传学改变、代谢组学特征及环境危险因素四个方面深入介绍了出生缺陷的发病机制;采用系统生物学观点和宏观社会科学相结合的手段,以科学理论为指导,科学技术为支撑,通过多角度,多层面相联合的方法,探讨我国出生缺陷三级预防发展的新趋势.     

The impact of early imprinting on the evolution of new venture networks

Given the argued importance of networks to new ventures, this paper is intended to fill a noted gap in the literature pertaining to the factors that influence the evolution of new ventures' alliance networks. Drawing on the imprinting literature, we propose that one has to look beyond the first partner per se, and instead focus on the extant relationships the initial partner has with other firms. More specifically, we argue and find that the network size and centrality of a new venture's initial alliance partner influence the subsequent size of the new venture's network.     

The impact of search costs on consumer behavior: A dynamic approach

Prices for grocery items differ across stores and time because of promotion periods. Consumers therefore have an incentive to search for the lowest prices. However, when a product is purchased infrequently, the effort to check the price every shopping trip might outweigh the benefit of spending less. I propose a structural model for storable goods that takes into account inventory holdings and search. The model is estimated using data on laundry detergent purchases. I find search costs play a large role in explaining purchase behavior, with consumers unaware of the price of detergent on 70 % of their shopping trips. Therefore, from the retailer’s point of view raising awareness of a promotion through advertising and displays is important. I also find a promotion for a particular product increases the consumer’s incentive to search. This change in incentives leads to an increase in category traffic, which from the store manager’s perspective is a desirable side effect of the promotion.     

Detecting the impact of market factors on sales takeoff times of analog cellular telephones

We use two approaches to model the hazard probability of the time-to-sales takeoff for cellular analog telephony to determine the impact of three market factors: price, number of competitors, and number of competing standards. We compare a fully parametric hazard model with discrete-time survival mixture analysis (DTSMA) in our study of data drawn from 70 countries from different economic sectors and geographic regions. Both approaches use control variables to capture observed heterogeneity. The possible relative advantage of DTSMA is its ability to recognize unobserved heterogeneity using latent classes. Failure to account for unobserved heterogeneity can cause underestimation of hazard probabilities; we investigate the change in inferences such an omission may cause. Applying DTSMA to this data set, we find that model parameters have appropriate signs and offer support for all three hypotheses: Relatively falling prices, relatively greater number of competitors, and relatively fewer competing standards are each associated with relatively higher hazard probabilities. In contrast, in the estimation of the fully parametric hazard model, we find that some parameters are wrongly signed, and only one hypothesis, the effect of competing standards, is supported.     

Increases in energy prices,costs of production,and plant size

A translog cost function is estimated for U.S. manufacturing in order to investigate plant size differences in responses to increases in energy prices. Smaller plants were more intensive users of energy in the early 1970s but were also better able to substitute out of energy and into other inputs during the first round of energy price increases. As a result, by the mid-1970s larger plants had become more intensive energy users. Thus, later energy price increases probably had a greater adverse impact on the production costs of larger plants in manufacturing.     

The impact of regulatory legislation on contractual costs risk and the form of contracts used in the UK and Republic of Ireland

The problem of contractual cost and quality risk within the public sector has been infrequently addressed within the EU regulated procurement environment. The view of Member States has been that concentration of buying power, standard conditions of contract and competitive bidding are the protective mechanism and cornerstones of regulated sector buyers. Aspects of the size of the ‘bidding pool’ and the influence of EU purchasing requirements are addressed and seen as largely unsatisfactorily addressed. This article provides an empirical analysis on two significant points:

• •that the UK and Republic of Ireland (ROI) public sector bodies have not significantly changed the type of contract (or contractual form) as a result of regulatory requirements.
• •that the form of contract adopted does not effectively address the cost and quality risks management may face once such contracts have been let.

     

Techno-economic case study on dedicated RAN for an intelligent transportation system: impact of the legislation-driven costs

Intelligent Transportation Systems (ITS) aim at improving daily travel experience. There are many promising communication technologies that could provide some ITS services. So far they have been predominantly evaluated from the technical point of view. This paper contributes a techno-economic evaluation of a case study on dedicated Radio Access Network (RAN) for public ITS. We analyze, calculate and compare Capital (CapEx) and Operational Expenditures (OpEx) for four different ITS-enabling wireless technologies: Ultra High Frequency standard, Wi-Fi 802.11n, Dedicated Short Range Communications (DSRC) 802.11p and LTE. This paper expands our results from Grigoryev et al. (2015). Here, we discuss in more details RAN planning and generalize legislation-driven cost influence on CapEx for DSRC and LTE deployments.     

异构蜂窝网络中用户关联与基站功率的协同优化

为实现异构蜂窝网络中宏基站和小基站之间的负载均衡,提出了一种基于效用函数最大化模型的用户关联机制和基站功率控制的协同优化方案。通过迭代算法求解该协同优化问题,首先在基站功率固定的情况下求得最佳用户关联策略,然后在所得的用户关联策略基础上通过Zoutendijk可行方向法求得基站最佳功率。通过协同优化获得的用户关联策略和基站功率控制实现了基站之间的负载均衡,通过降低宏基站功率和关闭闲置小基站降低了基站的能耗。仿真实验表明,所提方案和不实施功率控制的用户关联策略相比,实现了宏基站与小基站之间的负载均衡,降低了宏基站对小基站用户的干扰,提升了小基站用户的信号干扰噪声比,用户速率中位值提高了20%。     

The impact of different price promotions on customer retention

This paper investigates the impact of different price promotion effects regarding two different types of service cost (i.e., a joining fee vs. a monthly fee) on retention intentions for new customers in the long-term service industry. Based on the depreciation curve, mental accounting, and the escalation of commitment theory, we predict that customers’ retention intentions will be higher when they start using a service with a free monthly fee promotion rather than when they start it with a free joining fee promotion. This expectation was confirmed by five studies; experiments, customer survey, and secondary data. The theoretical and managerial implications are also discussed.     

The impact of different types of concernment on the consumption of organic food

Previous research has mainly focused on consumers' environmental values and attitudes to explain green consumption. However, it has been neglected how situational factors like the way a consumer is affected by the impacts of environmental pollution influence environmental attitudes and the demand for organic food products. To fill this void, we firstly introduce a taxonomy of different types of factual concernment and perceived concern. Factual concernment describes the manner in which a person is affected by the negative consequences of environmental pollution, whereas perceived concern expresses an anxious sense of interest. Building on that taxonomy, an experimental study analyses how four types of factual concernment (direct vs. indirect; material vs. immaterial) influence consumers' perceived concerns (in terms of environmental and health concern) as well as the readiness to gather information, the readiness to make sacrifices, the willingness to pay higher prices and purchase intentions. The study reveals that particularly direct concernment fosters the consumption of organic food. However, the study did not find any differences between the influences of material and immaterial concernment on the organic food purchase decision.     

The impact of basic human needs on the use of retailing self-service technologies: A study of self-determination theory

Self-service technologies (SSTs) are becoming increasingly popular in retailing contexts. Previous theories of SST adoption have largely ignored the basic human needs, such as competence, autonomy and relatedness, that drive customer motivation and the use of SSTs. We address this theoretical gap and examine self-determination theory (SDT) in the context of the supermarket self-checkout. Based on the argument proposed by SDT, self-determined motivation is hypothesized to mediate the relationships between autonomy, competence, and perceived anonymity, and the intention to use SSTs. Data collected from 361 respondents form a structural equation model and support these hypotheses. The current study is important as it helps understand the role of customers' participation in the self-service. Managerial and theoretical implications are suggested.     

不同通风方式对储粮降温保水的影响

通过比较不同的机械通风方式对小麦粮堆温度和水分的影响,确定经济有效的通风方式。     

The importance of understanding different complaint themes' impact on commitment

The research establishes that different complaint themes do not impact commitment with the same intensity. In other words, managers should not give the same amount of attention to all of the complaints received by the company. Thirty‐five complaints were recorded and eventually categorized into four groups. These groups were: (1) high price; (2) lacking a sense of community; (3) firm procedures; and (4) other. The fourth theme was labelled ‘other’ because of the heterogeneity that existed among the complaints that did not fit with the other three themes. These four themes were compared with each other concerning their effect on commitment. Because of the small sample size, a Kruskal‐Wallis test was used to analyse the data. Next, a post hoc test was conducted using a series of Mann‐Whitney tests. The results show that the theme with the most complaints (high price) did not have the biggest impact on commitment. Rather, another complaint (lacking a sense of community) demonstrated the largest impact on commitment. This research highlights the importance of analysing complaint groups with other relationship variables, and not just choosing the most frequently stated complaint as the area to improve an organization.     

New insights into the impact of the introduction of futures trading on stock price volatility

We examine whether, and to what extent, the introduction of trading in share futures contracts on individual stocks (i.e., individual share futures, or ISFs) has impacted on the systematic risk and volatility of the underlying shares. The use of ISFs allows a unique experimental design that complements existing work on index futures. Our major findings are as follows. First, we found a general reduction in systematic risk on individual stocks after the listing of futures. Second, we found evidence of a decline in unconditional volatility. Third, we found mixed evidence concerning the impact on conditional volatility. Fourth, the introduction of futures was found to impact on the market dynamics, as reflected by a change in the asymmetric volatility response, although the direction of that change is stock‐specific. In general, the results point to a number of features that are case‐specific and provide new insights into the mixed results that are typical of existing studies. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21:237–255, 2001