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1.
2.
《Socio》2021
Traffic congestion is an unpreventable problem to avoid in a transportation network and it has negative effects on traffic accident, time wasting, traffic delay and safety problem. Besides, in transportation networks, drivers do not want to deal with traffic jam while traversing between specified origin-destination pair. Therefore, traffic assignment (TA) is imperative to improve traffic management, transportation safety, time, and cost savings. System Optimum Traffic Assignment Problem (SOTAP) is a kind of TA model which aims to minimize the total system travel time on the network, and satisfies the flow conservation constraints. To model the SOTAP more realistically, the imprecise parameters can be taken as fuzzy. Therefore, in this paper, we focus on converting the conventional SOTAP to a fuzzy quadratic programming problem (QPP) which is named System Optimum Fuzzy Traffic Assignment Problem (SOFTAP). Here, link travel time is expressed with BPR function as generally used in the literature by converting to fuzzy except link-dependent parameters. Thus, the nonlinear objective function of SOFTAP is expressed in terms of fuzzy link flows and fuzzy link travel times. A solution approach from the literature is modified to the reconstructed SOFTAP. 相似文献
3.
建立产业共性技术研发外包博弈模型,从政府视角研究以共性技术产出最大化为目标的最优政府支持性研发外包合同,并对最优外包合同影响因素进行分析。研究表明:足够多的政府预算是共性技术政府支持性最优研发外包合同存在的前提,最优合同条款随政府预算的增大而增多,企业保留收益增大倒逼政府预算增加;企业最优知识技术投入与共性技术价值系数以及从研发中分享的收益份额正相关,与政府支付的固定研发费用负相关;政府最优知识技术投入与固定研发费用及单位投入成本系数负相关;企业最优投入与政府投入成本系数负相关,与政府投入对研发成功的贡献系数正相关,且企业最优投入随其研发能力的增强而加大。最后,根据研究结论,从政府预算、项目前景及支持性资源分配3个方面提出共性技术研发外包合同实施的政策建议。 相似文献
4.
机构投资者与政府补贴等优惠政策作为企业经营的重要资本来源和制度保障,势必对企业技术创新产生重要影响。以我国沪深两市战略性新兴上市企业2010-2015年面板数据为研究样本,对异质机构持股、政府补贴与企业技术创新的关系进行实证分析。结果发现:机构持股对企业技术创新没有显著影响,政府补贴可以促进机构持股对企业技术创新尤其是实质性技术创新产生显著正向影响;基金持股对企业技术创新存在显著负向影响,券商持股与QFII持股对企业技术创新分别存在不显著和显著正向影响;政府补贴能够降低基金持股对企业技术创新的负向影响,有效促进基金持股对企业技术创新的正向影响,并通过调节作用促进券商持股和QFII持股对企业技术创新产生更加显著的正向效应;政府补贴对基金持股与企业非实质性技术创新关系的正向调节作用更加显著,对券商持股和QFII持股与企业实质性技术创新关系的正向调节作用更加显著。 相似文献
5.
《International Journal of Forecasting》2019,35(1):80-99
This paper discusses the specifics of forecasting using factor-augmented predictive regressions under general loss functions. In line with the literature, we employ principal component analysis to extract factors from the set of predictors. In addition, we also extract information on the volatility of the series to be predicted, since the volatility is forecast-relevant under non-quadratic loss functions. We ensure asymptotic unbiasedness of the forecasts under the relevant loss by estimating the predictive regression through the minimization of the in-sample average loss. Finally, we select the most promising predictors for the series to be forecast by employing an information criterion that is tailored to the relevant loss. Using a large monthly data set for the US economy, we assess the proposed adjustments in a pseudo out-of-sample forecasting exercise for various variables. As expected, the use of estimation under the relevant loss is found to be effective. Using an additional volatility proxy as the predictor and conducting model selection that is tailored to the relevant loss function enhances the forecast performance significantly. 相似文献
6.
Funding for infrastructure projects recently shows that debt has a portion more than equity, triggering public debates. Therefore, leverage as an instrument to measure the ability and willingness of project sponsors to fund becomes the utmost importance to discuss. Relating to leverage, risk and government participation are two main factors that can explain the choice of funding decisions by the project sponsors. For this reason, this study would analyze the effect of risk and government participation on leverage through the two main sectors of infrastructure projects, namely the transportation sector and the energy sector, and derivating risk to political risk and financial risk. The objects of research were 976 infrastructure projects listed in the Asian Development Bank during 2007−2016. We use censored regression to examine the model by infrastructure sectors, both as individual and through interaction effects. The analysis showed that overall, leverage of infrastructure projects was rather influenced by financial risk than by political risk. However, the leverage of infrastructure projects in the transportation sector was more vulnerable to risk than that in other sectors. 相似文献
7.
从考察企业组织的敏捷性与交易成本的相互关系入手,对企业组织敏捷性的影响因素进行了剖析。详细分析了信息技术(IT)对提高企业组织敏捷性的作用机理。指出IT正是通过降低企业内、外部的交易成本、缩短流程时间、提高人的认识理性、扼制机会主义、促进企业组织结构、决策方式 相似文献
8.
Tim Power 《Revue internationale de statistique》2003,71(1):59-67
This paper outlines the ICT statistical developments that the ABS has undertaken over recent years. These developments have been on both the supply side (ICT industry) and the demand side (use of IT by sector). The content of ABS ICT surveys has changed significantly over the last few years and are expected to develop further in line with industry changes and emerging policy needs.
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field. 相似文献
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field. 相似文献
9.
Chikashi Tsuji 《Asia-Pacific Financial Markets》2003,10(2-3):163-185
The objective of this paper is to determine the best predictor of equity market crashes by focusing particularly on volatility and market liquidity. In finance, volatility has traditionally been regarded as the best measure of market risk. However, this paper shows that the forecast value of market liquidity, in particular our modified calculated market depth, predicts equity market crashes much more accurately than does the forecast values of EGARCH or Implied Volatility. 相似文献
10.
This paper demonstrates howadditional rents are generated in a fisherycharacterized by intraseasonal variation infish characteristics, including size,condition, and composition. Based on anexpanded conceptual model of the optimalharvest rule, fish characteristics affect preand post harvest production yields and outputprices. A dynamic empirical model, which uses asystem of quality characteristics and anhedonic equation, illustrates the complexrelationships and management choices associatedwith internalizing seafood qualitycharacteristics in a hake fishery. The modelretains the regulated open access managementsystem, but controls intertemporal andintersectoral quotas, production portfolios,and total allowable catch. Results demonstratethat including revenue-side effects frominternalizing fish quality can generatesignificantly greater rents and reduce therelative benefits of increased productionyields. If excluded, bioeconomic models canunderestimate the level of regulatory rentdissipation and overemphasize managementobjectives such as full utilization, whichcould misdirect processing decisions and resultin a suboptimal resource management plan.Implications for data collection,multidisciplinary analysis, and improvements inmarine resource management are discussed. 相似文献