关于我国企业竞争活动反应特性的相关关系研究

本文通过对竞争活动特性的实证分析论证了竞争反应数量及竞争反应迟延与各竞争特性、企业性质以及部分行业之间的关系。结论认为:一项竞争活动影响竞争者的数量以及该活动对于竞争者的战略重要性与竞争反应数量和速度呈正相关关系;战略活动和高竞争执行条件与竞争反应数量和速度呈负相关关系,相反,战术活动和低竞争执行条件却与竞争反应数量和速度呈正相关关系;国有企业对于竞争活动的反应无论从速度和数量上都低于私有企业。     

Pharmacovigilance in Clinical Trials: Current Practice and Challenges

In view of the MENA increasing participation in multinational trials and the increasing number of national/regional trials, this article explores potential areas of pharmacovigilance, requiring reform and provides recommendations for building a robust safety reporting system. Regulatory silence on expedited reporting requirements creates confusion for local sites that are part of multinational trials. Not allowing waiver for serious adverse events that are protocol specified or are study endpoints, along with lack of emphasis on causality as reporting criteria, adds substantial burden of uninformative cases for regulatory review. Despite global focus on Development Safety Update Report, local regulators are not yet insistent on real-time update of a drug’s cumulative safety profile. Issues like reporting requirements for generic trials, pregnancy reporting and lenient timeline for death/life-threatening events need attention. Finally, the need to formulate an all-encompassing local pharmacovigilance guideline, in sync with global practice cannot be overemphasized.     

Signal extraction goodness-of-fit diagnostic tests under model parameter uncertainty: Formulations and empirical evaluation

We present a time-domain goodness-of-fit (gof) diagnostic test that is based on signal-extraction variances for nonstationary time series. This diagnostic test extends the time-domain gof statistic of Maravall (2003 Maravall, A. (2003). A class of diagnostics in the ARIMA-model-based decomposition of a time series. Memorandum, Bank of Spain. Available at http://www.bde.es/servicio/software/tramo/diagnosticsamb.pdf [Google Scholar]) by taking into account the effects of model parameter uncertainty, utilizing theoretical results of McElroy and Holan (2009 McElroy, T., Holan, S. (2009). A local spectral approach for assessing time series model misspeci?cation. Journal of Multivariate Analysis 100:604–621.[Crossref], [Web of Science ®] , [Google Scholar]). We demonstrate that omitting this correction results in a severely undersized statistic. Adequate size and power are obtained in Monte Carlo studies for fairly short time series (10 to 15 years of monthly data). Our Monte Carlo studies of finite sample size and power consider different combinations of both signal and noise components using seasonal, trend, and irregular component models obtained via canonical decomposition. Details of the implementation appropriate for SARIMA models are given. We apply the gof diagnostic test statistics to several U.S. Census Bureau time series. The results generally corroborate the output of the automatic model selection procedure of the X-12-ARIMA software, which in contrast to our diagnostic test statistic does not involve hypothesis testing. We conclude that these diagnostic test statistics are a useful supplementary model-checking tool for practitioners engaged in the task of model-based seasonal adjustment.     

An Individual Mixed‐Evaluation Method for Career Intervention

Economic issues linked to career counseling are a cause for concern to policy makers in developed countries because they expect career practitioners to provide evidence of the efficiency of career counseling interventions. The aim of this study was to test an individual evaluation method mixing time series (outcomes) and life narrative (processes). The method used 5 items related to 1 client's career decision self‐efficacy and studied the evolution of those items throughout the intervention of 1 career counselor (43 days). Changepoint analysis helped in identifying the changes that have to be taken into account for time series and which are contextualized in the client's verbatim analysis. This mixed method highlighted that the career counselor's intervention increased the client's career decision self‐efficacy. Practitioners could use the methodology proposed in this article to evaluate their interventions. They could also report their practice to clients, employers, and decision makers.     

考虑零件三维装载约束带时间窗的循环取货路径问题研究

为提高车辆的可装载性,对考虑三维装载约束带时间窗的循环取货路径问题进行研究.在给定假设与约束条件的前提下,建立该问题的多目标数学模型,并设计用于问题求解的基于改进策略的启发式算法.数值实例的计算结果表明,该算法可有效求解考虑零件三维装载约束带时间窗的循环取货路径问题;且与时间窗优先法的求解结果相比,可大幅提高车辆的可装载性,并能有效减少不同车型车辆的投入数量.     

论后现代技术的品性和实践

以信息、语言、记忆工业和时间物体为代表的后现代技术,批判现代技术的机械化、商品化、功利化、权力化人类中心主义以及物化和异化带来的各类难以预测的事故和灾难。主张在非祛魅性、多元性、生态性和非决定论的后现代科学基础上,根除"技术官僚主义",推动后现代技术往更加人道、民主、自由、智慧和艺术的方向发展,将技术进一步人性化和真善美一体化,使其真正为新人民和全人类的文明服务。     

近三十年来《圆圆曲》研究综述

《圆圆曲》是吴伟业七言歌行的代表作之一。明末清初动荡的社会背景,陈圆圆风雨飘摇的身世遭际,引发了诗人的创作灵感,也赋予了该诗巨大的历史价值,故历来此法备受关注,研究成绩斐然。本文梳理了相关研究资料,试图从其历史真实性、创作时间、主题意旨、艺术手法,及与《长恨歌》等同类诗作的比较研究等方面,对近三十年来《圆圆曲》的研究现状做一综述,以期在总结中理清脉络,进而寻求新的学术研究空间。     

A Blueprint for Full Collective Flood Risk Estimation: Demonstration for European River Flooding

Floods are a natural hazard evolving in space and time according to meteorological and river basin dynamics, so that a single flood event can affect different regions over the event duration. This physical mechanism introduces spatio‐temporal relationships between flood records and losses at different locations over a given time window that should be taken into account for an effective assessment of the collective flood risk. However, since extreme floods are rare events, the limited number of historical records usually prevents a reliable frequency analysis. To overcome this limit, we move from the analysis of extreme events to the modeling of continuous stream flow records preserving spatio‐temporal correlation structures of the entire process, and making a more efficient use of the information provided by continuous flow records. The approach is based on the dynamic copula framework, which allows for splitting the modeling of spatio‐temporal properties by coupling suitable time series models accounting for temporal dynamics, and multivariate distributions describing spatial dependence. The model is applied to 490 stream flow sequences recorded across 10 of the largest river basins in central and eastern Europe (Danube, Rhine, Elbe, Oder, Waser, Meuse, Rhone, Seine, Loire, and Garonne). Using available proxy data to quantify local flood exposure and vulnerability, we show that the temporal dependence exerts a key role in reproducing interannual persistence, and thus magnitude and frequency of annual proxy flood losses aggregated at a basin‐wide scale, while copulas allow the preservation of the spatial dependence of losses at weekly and annual time scales.     

Information geodesics for gamma models of communication clustering

Recently, Akyildiz called for further work on non-Poisson models for communication arrivals in distributed networks such as cellular phone systems. The basic ‘random’ model for stochastic events is the Poisson process; for events on a line this resuits in an exponential disiribuuon of intervals between events. Network designers and managers need too monotor and quantify call clustering in order to optimize resaurce usage; the natural reference state from which to measure departures is that arising from a Poisson, process of calls. Here we consider gamma distributions, which contain exponential distributions as a special case. The surface representing gamma models has a natural Riemannian information metric and we obtain some geodesic sprays for this metric. The exponential distributions form a 1-dimensional subspace of the 2-dimensional space of all gamma distributions, so we have an isometric embedding of the random model as a subspace of the gamma models. This geometry may provide an appropriate structure on which to represent clustering as quantifiable departures from randomness and on which to impose dynamic control algorithms to optimize traffic at receiving nodes in distributed communication networks. In practice, we may expect correlation between call arrival times and call duration, reflecting for example peaks of different users of internet services. This would give rise to a twisted product of two surfaces with the twisting controlled by the correlation. Though bivariate gamma models do exist, such as Kibble's, none has tractabie information geometry nor sufficiently general marginal gammas,but a simulation method of approach is suggested.