The complexity of influence maximization problem in the deterministic linear threshold model

The influence maximization is an important problem in the field of social network. Informally it is to select few people to be activated in a social network such that their aggregated influence can make as many as possible people active. Kempe et al. gave a $(1-{1 \over e})$ -approximation algorithm for this problem in the linear threshold model and the independent cascade model. In addition, Chen et al. proved that the exact computation of the influence given a seed set is #P-hard in the linear threshold model. Both of the two models are based on randomized propagation, however such information might be obtained by surveys and data mining techniques. This will make great difference on the complexity of the problem. In this note, we study the complexity of the influence maximization problem in deterministic linear threshold model. We show that in the deterministic linear threshold model, there is no n ^1??? -factor polynomial time approximation for the problem unless P=NP. We also show that the exact computation of the influence given a seed set can be solved in polynomial time.     

Begegnung als ethische Maxime und Intervention im Coaching

Just as there is no universal understanding of what constitutes Coaching, there are no generally accepted ethical standards within Coaching. Opinions as to ethics within Coaching spring largely from the various ??Schools?? which transmit Coaching methods. Coaches working with J. L. Moreno??s Psychodrama follow the ethical and philosophical outlook contained in the analysis of creativity, spontaneity, the ??Social Atom?? and in the method, process orientated ??Encounter?? as understood by Moreno and Buber. That which they have internalised as ethical maxim and the Encounter method, is also understood to be a fundamental intervention.     

Der Einfluss von Kognition und Affekt auf Unternehmensgründungsentscheidungen: Eine vergleichende Analyse von Angestellten und Unternehmern

The relationship between individuals?? entrepreneurial behavior and objective situational characteristics of an entrepreneurial opportunity??individual-opportunity nexus??lies in the focus of entrepreneurship research. The role of subjective appraisals and affective influences in the pre-entrepreneurial process was neglected in this context so far. On the basis of a questionnaire experiment with two different samples of employees and entrepreneurs, our results confirm central assumptions of cognitive appraisal and emotion theories. The subjective appraisals of objective entrepreneurial opportunities better predict entrepreneurial evaluation and exploitation decisions than the objective characteristics of the entrepreneurial opportunity. Furthermore, the results show in addition to an inverse direct effect of negative affect that the relationship between the entrepreneurial evaluation and exploitation is negatively moderated by negative affect. Our analyses indicate that the two subsamples show differences in their cognitive processes, but that they are still generally comparable. The affective influences on the pre-entrepreneurial process, however, demonstrate no group specific differences. These results extend the individual-opportunity-nexus-paradigm that is based on objective characteristics by examining the meaning of subjective appraisals and affective reactions and therefore the intersection of individuals and entrepreneurial opportunities.     

中国文化背景下的组织人际和谐

采用问卷调查法,以中国3家企业340名员工为研究对象,以公平理论和社会交换理论为研究框架,提出领导公平、信息公平与组织人际和谐关系的研究模型。构建结构方程和层次回归模型,利用PASW STATISTICS 18.0和LISREL 8.80分析软件,采用探索性因子分析和验证性因子分析对组织人际和谐的三维结构观点进行检验,应用层级回归分析方法探讨领导公平、信息公平及其交互项对组织人际和谐的影响。研究结果表明,领导公平和信息公平对工具和谐具有显著的正向影响,但其交互项不显著;领导公平对价值和谐具有显著的负向影响,而信息公平对价值和谐具有显著的正向影响,交互效应显著;领导公平和信息公平对和谐阻碍的影响不显著,但其交互效应显著。     

中国股市限价指令簿的流动性提供研究

限价指令簿的流动性提供能力是描述其信息效率的主要指标。以上证180指数成分股的高频交易数据为样本,采用离散度和交易成本两个指标描述限价指令簿的流动性提供能力,并分别在市场和个股水平上分析其影响因素。研究结果表明,当预期市场波动增加时,限价指令簿的离散度上升,深度下降,供给的流动性减少,导致未来更高的真实波动。也就是说,流动性可以充当传递波动信息的管道,使投资者对未来波动率的预期成为现实,并主导实际市场波动。过去的市场走向是影响流动性供给的另一个重要因素,特别是当市场下滑时,限价指令簿的流动性供给将显著减少。在个股水平上,波动率和收益主要影响流动性的系统部分。     

Estimating Traffic Emissions Using Demographic and Socio-Economic Variables in 18 Chilean Urban Areas

A macro-scale methodology for vehicle emissions estimation is described. The methodology is based on both correlations between activity level and PM, CO, THC and NO _x vehicle emissions and relationships between demographic and socio-economic variables and transportation activity level. First, pollutant emissions were correlated with transportation activity, expressed as vehicle-km/year, using existing data collected from mobile sources emission inventories in nine urban cities of Chile. Second, demographic and socio-economic variables were pre-selected from those that could intuitively be correlated with vehicle activity level and considering the data availability. Using the individual R ² correlation coefficient as variable selection criterion, population, the number of vehicles, fuel consumption, gross domestic product, average family incomes and road kilometers were finally chosen. A different set of explicative variables was considered for different vehicle categories, based on the selection criterion above mentioned. Then, correlation functions between these variables and transport activity were obtained by non-linear Gauss–Newton least square method. This methodology was applied to eighteen provinces of the country obtaining total annual emission for mobile sources, divided into six main vehicles categories.     

The Capability Approach and Fuzzy Poverty Measures: An Application to the South African Context

One way of making the capability approach (CA) operational uses fuzzy poverty measures. In this paper, we present a new approach to applying these measures in the South African context using responses to a questionnaire on ‘The Essentials of Life’ in conjunction with a methodology for dealing with the vagueness of poverty. Our results suggest very low cut-offs for people or households to classify as definitely poor for some social indicators. These cut-offs are far lower than those Klasen used in his application of the CA. The attempt to apply the CA using Cheli and Lemmi’s ‘totally fuzzy and relative’ poverty measure in conjunction with our approach to specifying cut-offs can lead to incoherence. This measure can, nonetheless, be useful when social indicators have a ‘relativist component’. While the Cerioli and Zani measure does not lead to such incoherence, it also has a serious weakness.     

The educational attainment of second-generation immigrants in The Netherland

Since the mid-1960s the Netherlands has had a positive net immigration, mainly because of man power recruitment from Turkey and Morocco and immigration from the former Dutch colony of Surinam. Immigrants havea weak labor market position, which is related to their educational leveland language skills. Children and grandchildren of immigrants are expected to have a better chance of integration into Dutch society. In this paper we investigate whether this is true with respect to the educational attainment of second-generation immigrants from Turkey, Morocco, Surinam and the Dutch Antilles.The authors thank an anonymous referee and both editors for helpful comments. Responsible editors: David Card and Christoph M. Schmidt.