在线健康社区中用户回帖行为影响机理研究

 在线社交网络的持续发展和公民健康意识的不断增强促进了在线健康社区的兴起和繁荣。健康社区为用户提供了一个获取医疗资源并分享知识、经验和情感的开放式平台。由于其在为用户和患者提供丰富的医疗信息和知识资源、满足用户间的社交需求等方面表现突出，近年来，国内外在线健康社区都出现了蓬勃发展的态势。        在社区的各种行为中，发帖和回帖是社区中用户社交行为的重要体现，是维系社区繁荣的根本，因此对社区中用户回帖行为的影响机理进行研究具有重要的意义。        以糖尿病在线健康社区甜蜜家园网站为研究对象，基于该网站2015年1月~6月的社区发帖和回帖数据以及所有用户的个人信息数据，构建健康社区的用户回帖有向网络，该网络包含边和节点两部分属性信息；运用指数随机图模型，探讨该网络中网络结构和节点属性对回帖网络形成的影响机理。        研究结果表明，回帖网络同时具有互惠性和传递性特征，互惠性表明社区中的用户倾向于互相回帖，传递性表明该网络有很好的发展潜力。节点属性对用户回帖行为的影响机制较为复杂，其中，用户倾向于对同质性(类型同质性)用户回帖；社会资本(如好友数量、活跃度)高的用户能获得更高的回帖概率；大量给他人回帖的用户和新用户更易获得他人的回帖。        研究结果进一步丰富了在线健康社区中用户行为机理的研究范式，以及电子健康、在线社交网络、健康社区、论坛回帖行为等领域的研究，并对社区的管理有一定的启示作用；有利于指导社区的设计机制，如鼓励新人多发帖、引导有较大影响力的用户(如管理者和活跃度高的用户)发帖互动、进一步促进同质用户间的信息交流等，这些机制进一步促进和引导论坛中用户间的信息交互，对论坛持续繁荣发挥重要作用。     

量化自我的效应及其对消费者参与行为的影响机制

 对亚健康等社会问题的担忧以及商业性智能应用和可穿戴量化设备的出现和推广，使越来越多的消费者参与量化自我，追踪测量自我活动水平和健康状况等。学界和业界对消费者的量化自我关注趋增，已有研究明确了量化自我概念内涵和类型，强调量化自我对优化和管控消费者行为具有积极效用。但已有研究并未探明量化自我对消费者活动参与行为的影响及其内在机制，且尚未形成整合的消费者量化自我分析框架。        构建整合的理论框架，以探明量化自我效应及其影响消费者活动参与行为的心理机制，对量化自我过程中消费者的行为反应作出合理解释，从个体认知差异视角出发，基于认知失调理论，结合消费者的自尊水平与测量反馈感知不一致，对量化自我影响消费者活动参与行为的心理机制进行分析，探讨量化对消费者活动参与绩效的影响、感知不一致和自尊水平对消费者提升量化活动参与绩效意愿的影响，以及消费者自我概念清晰性对该影响的中介效应。运用实验研究方法，采用测量阅读页数的实验研究设计，借助方差分析和Bootstrap方法检验量化自我效应及其影响消费者活动参与行为的内在机制，明确消费者自尊水平与感知不一致的交互作用以及自我概念清晰性的中介机制。        研究结果表明，与非量化情景相比，量化自我将增进消费者活动参与绩效，量化将使消费者更易感知到先前未觉的目标预期与实际行为的不一致。当存在量化条件时，消费者往往会主动选择参与量化自我。量化自我过程中，消费者的自尊水平与测量反馈感知不一致同时影响其提升量化活动参与绩效的意愿，且自我概念清晰性在这一过程中起中介作用。当感知到积极不一致时，低自尊消费者较高自尊消费者的自我概念清晰性更低，且低自尊消费者对积极感知不一致反应越强烈，其自我概念清晰性越低，继而提升量化活动参与绩效的意愿越强；当感知到消极不一致时，高自尊消费者比低自尊消费者的自我概念清晰性更低，且高自尊消费者对消极感知不一致反应越强烈，其自我概念清晰性越低，继而提升量化活动参与绩效的意愿越强。        研究结果在丰富相关理论、深入理解量化自我内在机制的同时，对企业驱动消费者参与量化活动、科学设计和开发产品、呈现和传递信息等具有重要实践意义。     

离职倾向与行为表现的关系：自我效能感和主动性人格的调节作用

  员工离职一直以来是理论界和实务界关注的热点，对员工离职的研究主要聚焦于员工离职倾向和离职行为，并主要从个体和情景因素探讨员工离职倾向或离职行为的影响因素，但具有离职倾向却未发生实际离职行为的员工在组织中表现如何，还有待进一步研究。         根据计划行为理论，个体会基于自己的内在倾向采取相应的行为，但是内在倾向与行为之间的关系受到一定的约束，尤其受到个体是否能够决定或控制这种行为的影响。自我效能感反映了个体认为自己能够处理问题的信心，主动性人格则反映了个体是否具有按照自己的意愿采取行为的自主权，二者均反映了个体对行为的控制度。构建以离职倾向为前因变量，以自我效能感和主动性人格为调节变量，以任务绩效、帮助行为和反生产行为为结果变量的理论模型。基于886名员工和231名配对领导的两阶段数据，使用Mplus 7.0进行数据分析和假设检验。为避免领导评价的嵌套效应，采用三明治分析方法进行分析。         研究结果表明，①自我效能感正向调节离职倾向与反生产行为的正向关系，即高自我效能感的员工在相同水平离职倾向下会做出更多反生产行为；②主动性人格正向调节离职倾向与任务绩效的负向关系，即高主动性人格的员工在相同水平离职倾向下表现出更差的任务绩效；③主动性人格正向调节离职倾向与帮助行为的负向关系，即高主动性人格的员工在相同水平离职倾向下会做出更少帮助行为；④主动性人格正向调节离职倾向与反生产行为的正向关系，即高主动性人格的个体在相同水平离职倾向下会做出更多反生产行为。         研究发现离职意愿提高员工反生产行为，在产生离职倾向后高自我效能感和高主动人格的员工更会有消极表现。研究结果启示管理者需多观察员工行为，把握员工离职倾向，重视主动性人格可能存在的消极作用，引导主动性人格的员工发挥积极作用。     

应用特征与个体特质双重视角下移动购物持续使用意愿研究

 移动购物是提供购物服务的一种移动商务模式,它真正实现移动与购物的完美结合。随着移动购物的普及,移动购物用户的持续使用问题引起普遍关注。现有用户的留存率不仅影响移动购物企业的盈利水平,也是衡量企业是否成功的重要标准。因此,研究用户持续使用意愿的影响因素,对于移动购物企业在当前激烈竞争中保持优势有重要意义。        基于沉浸理论、隐私计算理论和已有的相关研究,聚焦用户移动购物的体验,从移动购物应用特征和用户个体特质双重视角出发,将移动购物的用户体验划分为沉浸体验特性、沉浸体验权衡状态、沉浸体验结果3个阶段,构建移动购物用户持续使用意愿影响因素三阶段模型;采用问卷调查法,运用Spss 19.0和Amos 22.0对收集的346份有效数据进行结构方程路径分析,以验证提出的研究假设。        研究结果表明,体现移动购物应用特征方面的感知质量、感知交互和感知愉悦显著提高用户信任,感知愉悦的影响最大,感知质量和感知愉悦显著缓解用户的隐私担忧;体现用户个体特质的涉入度和自我效能对用户信任产生积极影响,专注度和涉入度能够缓解用户对个人隐私的担忧;用户通过信任和隐私担忧的权衡决定是否持续使用该移动购物应用,且信任和隐私担忧通过影响自我披露意愿间接影响用户持续使用意愿。        研究结论不仅为学者全面而深入探究移动购物用户持续使用意愿提供了理论依据,还为移动应用开发商和移动服务商开发设计有效的移动购物应用,提高现有用户的留存率,进而促进移动购物企业盈利提供了一些对策和建议。     

理性+情感：Apple Pay使用意愿的实证研究

  基于理性认知的经典技术接受理论已经难以全面解析用户对于支付服务的使用行为和意愿,与此同时,用户附着在各种移动支付服务上的情感却存在很大的差异,对于一些新兴小众产品,用户投射在其上的情感强度很可能潜在地成为其在商业上取得成功的关键。作为一种小众支付服务的Apple Pay,自上市以来,用户的使用意愿低一直是其发展过程中遇到的最大问题,因此,有必要研究情感因素与理性因素如何相互作用并影响用户对Apple Pay的使用意愿。         基于计划行为理论,结合情感依恋视角,构建用户对Apple Pay使用意愿的理论模型,并探究情感依恋影响用户使用意愿的机制。为验证研究假设,在线收集202份有效问卷,采用SmartPLS 2.0软件进行实证分析。         研究结果表明,①感知收益、社会规范和移动支付经验对用户使用Apple Pay的意愿有显著的正向影响;②情感依恋对用户使用Apple Pay的意愿有显著的直接作用,还会显著削弱感知收益和移动支付经验对用户使用Apple Pay意愿的正向作用,并边际增强社会规范与用户使用Apple Pay意愿之间的关系。         在理论层面,界定了情感依恋对于用户采纳Apple Pay的影响,在一定程度上拓展了技术接受理论,并将情感依恋和计划行为理论统一到一个理论框架内。同时揭示了情感依恋会降低用户采纳Apple Pay时的条件要求,可以为后续对非理性因素的研究提供思路。在管理实践层面,研究结果也对Apple Pay这类小众产品在技术趋同而又竞争激烈环境下的推广具有重要的指导意义。     

上级发展性反馈与创造力：一个被调节的中介模型

 在当前复杂和快速变革的环境中,创造力对组织获取竞争优势至关重要。作为与创造力相关联的重要因素,研究者们对于领导行为对创造力的作用保持了长期的关注。反馈不仅是领导者日常行为的重要组成部分之一,也是组织中常用的激励和行为矫正工具。        以自我效能理论和关系认同理论为基础,从领导和组织成员互动视角,探讨上级发展性反馈对组织成员创造力的影响及其内在机制。采用问卷调查方法,通过3阶段分时序方式,收集来自某综合性重点大学所属科研团队的442位科研人员及其领导的配对数据,运用层次回归和Bootstrap方法进行数据分析和假设验证。        研究结果表明,①上级发展性反馈正向影响组织成员创造力;②创新自我效能部分中介上级发展性反馈与组织成员创造力之间的关系;③组织成员对领导的关系认同感调节上级发展性反馈与创新自我效能之间的关系,并进一步调节创新自我效能在上级发展性反馈与组织成员创造力之间的中介作用,即当组织成员对领导的关系认同感高时创新自我效能的中介作用显著,而当关系认同感低时创新自我效能的中介作用不显著。        研究结果在一定程度上扩展了对于领导反馈与创造力间关系的理解,丰富了上级发展性反馈影响创造力的内在机制的探索,发现了上级发展性反馈影响组织成员创造力的重要边界之一,也一定程度上丰富了关系认同理论的运用范围,领导者可以通过提供发展性反馈以及与组织成员建立良好的关系来促进其创造力。     

用户生成内容的图文匹配对消费者感知有用性的影响

 互联网带来的“信息爆炸”使消费者更频繁地借助用户生成内容获取产品信息和产品使用体验。用户生成内容的感知效应和劝说效应深刻地影响着消费者的购买决策，感知效应增加了消费者对产品或服务的感知，劝说效应增加了消费者的购买意愿。Web 2.0时代，网络口碑的主要形式为图片评论和文字评论，目前图文结合的用户生成内容作为网络口碑的新形式受到广泛关注。        从图文一致性和图文位置关系两个视角剖析图文结合的用户生成内容对消费者感知有用性的影响，为增加研究结果的内部效度，采用情景模拟实验法，通过4个实验，借助SPSS统计分析软件对实验数据进行处理，均以中国某高校的本科学生作为样本。        根据双重通道编码理论，研究1验证图文结合的用户生成内容是更有效的网络口碑传播形式。研究2从图片类型出发，检验消费者感知有用性的差异，并验证产品类别对图文结合的用户生成内容与消费者感知有用性之间的调节作用。结果表明，对于享乐型产品，社会型图片比功能型文本对消费者更有用；对于实用型产品，功能型图片比功能型文本和社会型文本对消费者来说更有用。研究3以图文的空间距离作为自变量、以消费者感知有用性作为因变量进行研究，结果表明，与图文远离呈现的用户生成内容相比，当消费者浏览的是图文临近呈现的用户生成内容时，其感知有用性更高。研究4在研究3的基础上对图文位置关系进行深入研究，结果表明，如果消费者更关注文本信息，左图右文的图文位置关系更有助于消费者理解产品信息；如果消费者更关注图片信息，上图下文的图文位置关系更有用；如果消费者对文本和图片信息都比较关注，右图左文或下图上文的图文位置关系更有用。        研究结果不仅对深化和完善图文结合的用户生成内容相关理论具有理论意义，而且对指导营销者和电子商务网站进行营销创新、增强营销效果和帮助消费者了解产品信息有重要的现实意义。     

员工优势使用对创新行为 的影响机制研究

  随着积极心理学的发展,优势理论受到学者们的广泛关注。优势使用理论作为优势理论的核心内容,它认为个体优势使用不仅能够提升个体的幸福感、工作投入、自我效能感和绩效,而且还能降低个体的工作压力和缺勤率。尽管大量的研究表明员工优势使用有益于员工的成长和发展,但是员工优势使用与创新行为之间关系的研究还未受到应有的重视。         以工作要求资源理论为理论基础,在中国情景下探讨员工优势使用与创新行为之间的关系以及创新自我效能感和创新时间压力在两者之间的中介作用。采用问卷调查方法在3个时间点收集数据,共得到226份工作在中国各类型企业中的有效员工样本。通过Spss 22.0软件采用多元线性回归和Bootstrap检验方法,对构建的员工优势使用对创新行为影响机制模型进行验证。         研究结果表明,员工优势使用对员工创新行为和创新自我效能感有显著的正向影响,对创新时间压力有显著的负向影响;员工优势使用不仅能够通过促进创新自我效能感提升创新行为,而且还能通过降低创新时间压力对创新行为产生影响。         研究结果为员工创新行为驱动力研究提供了新视角;进一步丰富了员工优势使用的影响效应研究;有助于深入理解员工优势使用与创新行为之间的转化机制以及打开两者之间关系的黑箱,拓展员工优势与创新关系理论的跨群体适用性;有助于丰富工作要求资源理论的应用范围和内涵。对于如何构建和执行基于优势的人力资源管理实践以及如何管理员工的创新自我效能感和创新时间压力以便促进员工创新行为具有重要的意义。     

基于多源大数据的个性化推荐系统效果研究

  个性化推荐系统已成为各大电商向消费者提供个性化购物体验的重要工具之一,通过推荐系统,商家可以提高收入和消费者满意度。但传统推荐系统通常只利用消费者在当前网站的历史信息推荐个性化商品,无法获得消费者在其他网站的数据来优化推荐效果。大数据时代,一些第三方公司抓住机遇,利用不同公司的多源大数据提供更好的个性化推荐服务。然而,这种新型的推荐系统对消费者购物行为的影响存在极大的未知性。         探究基于多源大数据的个性化推荐系统对消费者购物行为的影响。为了建立推荐系统与消费者购物行为之间的因果关系,采用实地实验有效地避免传统研究方法存在的内生性问题,并具有较好的外部有效性。一方面,基于内部数据和外部数据构造解释性变量,探究内部数据特征和外部数据特征与推荐效果之间的关系;另一方面,通过检验消费者特征与内外部数据的推荐效果间的交互效应,进一步分析外部数据和内部数据的推荐效果如何随消费者的特征变化,帮助企业更好地利用多源大数据提升推荐效果。         研究结果表明,基于内部数据的推荐系统能够显著提升消费者点击个性化推荐商品的概率,可以降低消费者决策时间,激励消费者浏览更多的商品。外部数据的推荐效果不仅与外部公司网站的用户数量相关,也会受到外部网站与当前网站的关联程度的影响。消费者特征对基于内部数据和外部数据的推荐效果起调节作用,如果消费者是当前网站的老用户,利用该消费者在当前网站的内部数据提供个性化推荐的效果更佳。         通过分析基于多源大数据的推荐效果对消费者购物行为的影响,进一步完善个性化推荐领域的理论框架。研究结果对如何利用多源数据构建更加有效的推荐系统具有重要指导价值,并为不同网站之间的数据共享机制提供重要的管理建议。     

强制情景下最终用户的采纳意愿研究

 中国人口老龄化已经进入快速发展期，为提高养老院的医疗服务质量，养老机构在医疗信息系统上投入了大量的财力和人力，但使用的效率并不高。象征接受被认为是导致医疗信息系统无法实现其预期效用的根源，因此识别老人们象征接受的影响因素进而制定相应的管理策略已然变得十分迫切。        选取一家公办养老院和一家民办养老院作为研究对象，调查对象为养老院内的老人。采用现场发放问卷和现场回收的方式获取数据，以提高问卷的回收率。为避免共同方法偏差对研究结果的影响，采用分时间段的问卷调查法，对336位老人展开为期6个月的问卷调查。使用SPSS 20.0和AMOS 21.0对数据进行探索性因子分析、验证性因子分析、描述性统计分析和内部一致性分析等，采用多层线性分析和总效应调节分析法验证认知失调在象征接受与采纳意愿之间的中介效应和任务价值在象征接受与认知失调之间的调节作用，以探讨强制用户使用医疗信息系统后，用户认知转变的过程机制以及采纳意愿形成的边界条件。        研究结果表明，在医疗信息系统实施过程中，对于服从个性较强的人，管理者的职位权力能直接导致用户象征性采纳行为，继而在用户内部出现认知失调的情绪，经过一个试用期，认知失调才能完全消失，最终产生实质性的采纳意愿；用户的任务价值对认知失调情绪起关键性的消除作用。对于服从性较弱的人，他们并没有经历认知失调，其象征性采纳可以直接转化为实质性采纳。        研究结果有助于厘清强迫服从情景下用户认知转变的内在机制，通过个体差异与组织情景交互视角，探讨医疗信息系统采纳意愿形成的边界条件，对养老院的管理者有效消除医疗信息系统实施过程中的抗拒心理、提升系统的使用效率具有实践意义。     

Criteria for selecting a production control philosophy

Logistic objectives constitute a compromise between having short leadtimes and a low volume of work in progress on the one hand and a high resource loading and due date obligation on the other. Miscellaneous production planning approaches offered today provide different combinations of logistic objectives for satisfying a manufacturing strategy. To combine the strength of the various approaches into a unified system, a new approach based on a dynamic and distributed production planning methodology is proposed. To customize the approach, various analyses and specifications have to be made and for that reason some important characteristics and criteria for analysing production control philosophies will be given.     

The social construction of the meaning of acute stressors: a qualitative study of the personal accounts of police officers using a stress counselling service

The police profession is one in which acute stressors are encountered more frequently than in other occupations. Using the personal accounts of 35 police officers attending an in-house stress counselling clinic, the aim of the present study was to provide a qualitative examination of how the institutional context of policing influenced the ways in which acute stressors signified to individual police officers experiencing felt distress. Using the framework of Rational Emotive Behaviour Therapy as an analytical tool, it is argued that beliefs contributing to the experience of felt distress are related to the way in which policing as both an identity and an activity is constructed through the police organizational culture. Not only do these constructions influence the ways in which officers perceive themselves and their environments, but they also operate at the collective level to 'normalize' some emotional responses and to 'pathologize' others which, it is argued, could impact upon the outcomes of interventions such as stress counselling.     

The moderating role of social support in Karasek's job strain model

This paper examines whether social support is a boundary-determining criterion in the job strain model of Karasek (1979). The particular focus is the extent to which different sources of social support, work overload and task control influence job satisfaction, depersonalization and supervisor assessments of work performance. Hypotheses are tested using prospective survey data from 80 clerical staff in a university setting. Results revealed 3-way interactions among levels of support (supervisor, co-worker, non-work), perceived task control and work overload on levels of work performance and employee adjustment (self-report). After controlling for levels of negative affect in all analyses, there was evidence that high levels of supervisor support mitigated against the negative effects of high strain jobs on levels of job satisfaction and reduced reported levels of depersonalization. Moreover, high levels of non-work support and co-worker support also mitigated against the negative effects of high strain jobs on levels of work performance. The results are discussed in terms of the importance of social support networks both at, and beyond, the work context.     

Job insecurity, coping resources and personality dispositions in occupational strain

This paper presents research on the relationships between the work-related stressor of perceived job insecurity and various indicators of occupational strain, taking into account employees' personality dispositions (trait negative and positive affectivity) and coping resources. Respondents were 222 Australian public servants surveyed during organizational restructuring that involved downsizing and threat to job certainty. The research was formulated within an adaptation of Osipow, Doty, and Spokane's (1985) framework of stress-strain-coping that included the possible direct as well as moderating effects of personality dispositions in reporting occupational strain (Parkes, 1990). Findings from hierarchical regression analyses indicate consistent significant independent effects of personality dispositions, coping resources and perceived job insecurity on various indicators of strain. There was also support for the moderating roles of negative affectivity and self-care in the relation between perceived job insecurity and physical strain. Implications for the role of dispositional factors, especially negative affectivity, and the utility of various coping resources in accounting for occupational strain in times of threatened job security are discussed.     

Introduction to Special Section on Sensitivity Analysis and Summary of NCSU/USDA Workshop on Sensitivity Analysis

This guest editorial is a summary of the NCSU/USDA Workshop on Sensitivity Analysis held June 11–12, 2001 at North Carolina State University and sponsored by the U.S. Department of Agriculture's Office of Risk Assessment and Cost Benefit Analysis. The objective of the workshop was to learn across disciplines in identifying, evaluating, and recommending sensitivity analysis methods and practices for application to food‐safety process risk models. The workshop included presentations regarding the Hazard Assessment and Critical Control Points (HACCP) framework used in food‐safety risk assessment, a survey of sensitivity analysis methods, invited white papers on sensitivity analysis, and invited case studies regarding risk assessment of microbial pathogens in food. Based on the sharing of interdisciplinary information represented by the presentations, the workshop participants, divided into breakout sessions, responded to three trigger questions: What are the key criteria for sensitivity analysis methods applied to food‐safety risk assessment? What sensitivity analysis methods are most promising for application to food safety and risk assessment? and What are the key needs for implementation and demonstration of such methods? The workshop produced agreement regarding key criteria for sensitivity analysis methods and the need to use two or more methods to try to obtain robust insights. Recommendations were made regarding a guideline document to assist practitioners in selecting, applying, interpreting, and reporting the results of sensitivity analysis.     

Job stress, job strain, and psychological withdrawal among Dutch university staff: towards a dualprocess model for the effects of occupational stress

This study examined the antecedents of job strain (emotional exhaustion, health complaints) and withdrawal behaviour (e.g. lowered organizational commitment) among a cross-sectional sample of 131 academic staff members of the law department of a large Dutch university. Conservation of resources theory (Hobfoll, 1989) provided the theoretical background for this study. Strains and withdrawal behaviours were expected to be most prominent among those who reported having few resources and/or who reported high job demands. Structural equation modelling revealed that this was indeed the case. As predicted, differential patterns of effects emerged for job demands and job resources. Analysis of the effects of four job-specific stressors revealed that especially the structural aspects of a staff member's teaching task (e.g. the number of students in their classes) contributed strongly to perceived job demands. Theoretical and practical implications of the study are discussed.     

Distinguishing traumatic, vicarious and routine operational stressor exposure and attendant adverse consequences in a sample of police officers

Problems in studying occupational stress within the police service are identified and the paucity of work on operational duties as potential stressors are discussed. The present study reports the results of a factor analysis of operational stressors (N = 601 serving British police officers) that revealed three factors: exposure to death and disaster; violence and injury; sexual crime. These were demonstrated to be reliable scales and were included in logistic regression models together with a range of demographic and psychological variables. Models were applied to men and women separately, which showed there to be different predictors of the likelihood of suffering distress (measured by the General Health Questionnaire, GHQ) in terms of the officer's gender and operational role. Overall the model for women officers was better at predicting psychological distress than that for men. These findings are related to aspects of the police occupational culture. Further discussion is offered that conceptualizes police operational stressors as traumatic, routine and vicarious. Finally, some implications are drawn for the provision of stress intervention in the light of this differentiation.     

Dermal Uptake of 18 Dilute Aqueous Chemicals: In Vivo Disappearance‐Method Measures Greatly Exceed In Vitro‐Based Predictions

Average rates of total dermal uptake (K_up) from short‐term (e.g., bathing) contact with dilute aqueous organic chemicals (DAOCs) are typically estimated from steady‐state in vitro diffusion‐cell measures of chemical permeability (K_p) through skin into receptor solution. Widely used (“PCR‐vitro”) methods estimate K_up by applying diffusion theory to increase K_p predictions made by a physico‐chemical regression (PCR) model that was fit to a large set of K_p measures. Here, K_up predictions for 18 DAOCs made by three PCR‐vitro models (EPA, NIOSH, and MH) were compared to previous in vivo measures obtained by methods unlikely to underestimate K_up. A new PCR model fit to all 18 measures is accurate to within approximately threefold (r = 0.91, p < 10^?5), but the PCR‐vitro predictions (r > 0.63) all tend to underestimate the K_up measures by mean factors (UF, and p value for testing UF = 1) of 10 (EPA, p < 10^?6), 11 (NIOSH, p < 10^?8), and 6.2 (MH, p = 0.018). For all three PCR‐vitro models, log(UF) correlates negatively with molecular weight (r² = 0.31 to 0.84, p = 0.017 to < 10^?6) but not with log(vapor pressure) as an additional predictor (p > 0.05), so vapor pressure appears not to explain the significant in vivo/PCR‐vitro discrepancy. Until this discrepancy is explained, careful in vivo measures of K_up should be obtained for more chemicals, the expanded in vivo database should be compared to in vitro‐based predictions, and in vivo data should be considered in assessing aqueous dermal exposure and its uncertainty.     

Systems Resilience for Multihazard Environments: Definition,Metrics, and Valuation for Decision Making

The United Nations Office for Disaster Risk Reduction reported that the 2011 natural disasters, including the earthquake and tsunami that struck Japan, resulted in $366 billion in direct damages and 29,782 fatalities worldwide. Storms and floods accounted for up to 70% of the 302 natural disasters worldwide in 2011, with earthquakes producing the greatest number of fatalities. Average annual losses in the United States amount to about $55 billion. Enhancing community and system resilience could lead to massive savings through risk reduction and expeditious recovery. The rational management of such reduction and recovery is facilitated by an appropriate definition of resilience and associated metrics. In this article, a resilience definition is provided that meets a set of requirements with clear relationships to the metrics of the relevant abstract notions of reliability and risk. Those metrics also meet logically consistent requirements drawn from measure theory, and provide a sound basis for the development of effective decision‐making tools for multihazard environments. Improving the resiliency of a system to meet target levels requires the examination of system enhancement alternatives in economic terms, within a decision‐making framework. Relevant decision analysis methods would typically require the examination of resilience based on its valuation by society at large. The article provides methods for valuation and benefit‐cost analysis based on concepts from risk analysis and management.     

UNIX系统性能监控简述及shell系统资源统计程序

本文简要阐述了unix系统中(主要以IBM的AIX为例)进行系统性能管理的几种命令行工具,并通过编写shell实例程序,运用其中提到的工具实现系统资源利用率的统计程序,为做好unix系统管理和调优提供参考.