Automatic train control based on magnetic bridge

This system of automatic train control employs an alternating magnetic Wheatstone bridge for receiving stop indications from inert track inductors, whereby air brakes of a train approaching a danger zone are operated to stop the train. The bridge is a reversible variocoupled transformer, and the inductor is a flux-reverser and phase shifter. A “reflector” reactor at the signal permits clear indications of the train control and prevents false clear indications if the cable between the reflector and the inductor should become short-circuited. The magnetic bridge is adaptable to many uses in other industries, and is extensively used for detecting vehicles in street traffic control systems.     

Stabilization of carrier-frequency servomechanisms. II. Design formulae for proportional-derivative networks

In an alternating current servomechanism, the error is proportional to the modulation envelope of a modulated-carrier error signal. It is shown in part I that for stability and fidelity of the servo, it is highly desirable that the effect of the controller includes a proportional-derivative action on the modulation envelope. This action may be obtained with various forms of RC networks, including the parallel “T,” bridge “T,” and Wien Bridge forms.This part contains detailed design procedures and tables of values for the various types of proportional-derivative networks. Several forms of parallel “T” networks arise from the fact that there are five independent time constants in the network, while in order to realize the desired transfer characteristic it is necessary to impose only four conditions. It is indicated how the remaining degree of freedom may be used to obtain the most suitable input and output impedances for the source and load impedances with which the parallel “T” is to be used. The derivations for the parallel “T” formulae are given in an Appendix.Tolerance requirements on the components of parallel “T” and bridge “T” networks are derived. If ±1 per cent components are used at 60 cycles, the resonant frequency will lie between 56.4 and 63.6 cycles, and the notch width (rejection band width) will be within ±0.99 cps. of the correct value. In order to guarantee that the phase shift at 60 cycles is within ±10°, the percentage deviation of each part must be less than ($\text{9.0}\text{T}{}_{\mathrm{d}}\text{ω}{}_0$), where ω₀ is the carrier angular frequency, T_d the derivative time constant.     

“Context” in healthcare information technology resistance: A systematic review of extant literature and agenda for future research

Resistance to Healthcare Information Technologies (HIT) continues to be a major challenge that hampers the realization of benefits. Attending to the noted significance of “context” in IT resistance, we carried out this review to understand how the “context” of healthcare in the extant HIT resistance literature has been studied. Based on a review of HIT resistance across 19 IS journals and 5 major IS conferences we organize and summarize the literature around the interaction of people, practice, and technology and provide several significant possibilities for future research.     

担忧和期待：关于“全面放开竞争性领域商品服务和价格”的政策述评

党的十八届五中全会指出,全面深化改革的一项重要任务,即完善社会主义市场经济体制建立市场决定价格机制。就社会主义市场经济而言,“全面放开竞争性领域商品服务和价格”是价格改革中的“关键性战役”,面对“全面放开”之后的担忧和期待,本文从“政府说了算”还是“市场说了算”,“收”“放”之“困”从何而来,“经济新常态”下的必然选择,未来政策走向及经济影响四个方面论述了市场经济条件下全面实现市场决定价格机制的作用和意义。     

“美国国防高级研究计划局”（DARPA）如何跨越“死亡之谷”?

“死亡之谷”是发明到产品之间的鸿沟,“美国高级研究计划局”（DARPA）在短短50多年时间里,为世界带来了互联网、GPS等技术与产品,常常成功跨越鸿沟。从产业发展角度,跨越“死亡之谷”需要物质、智力和社会等三种资本,还要跨越技术培育和转移各个关键阶段。DARPA利用其独特的政治地位、雄厚的资金和有远见的战略思想,依靠优秀项目官员、办公室主任和局长的协同合作,以及长年培育的“DARPA社区”,一次次成功跨越“死亡之谷”。近年,DARPA为缩短跨越“死亡之谷”的时间,还采取了“众包”等一系列新举措,最后总结了DARPA成功跨越“死亡之谷”的关键。     

基于创业学课程实施动态教学模式

创新与创业的社会高潮使得创业教育日趋升温。传授创业课程的关键在于教师能否构建一个全新的教学模式,并发展创新一套适合创业课程的教学方法,来培养学生充满自信、自强和勤奋好学的“毅力”;诱发学生参与教学的“活力”;造就学生自主创业的“能力”;培育学生团结、友爱、协作的“团队精神”;开启学生洞察创新与创业的意识。为此本文针对如何在创业学课程中实施动态教学模式进行了专题探讨。     

Antecedents of resistance to enterprise systems: The IT leadership perspective

The objective of this study is to determine the resistance antecedents to enterprise systems. Thus, by reviewing the extant literature with respect to resistance behavior to information systems, a theoretical model containing the factors that influence user resistance behavior to enterprise systems was compiled. Then, via a web survey, 169 valid questionnaires filled out by Brazilian IT managers who had already implemented enterprise resource planning (ERP) systems were obtained. From there, the research drew on factor analysis and structural equation modeling techniques to refine and test the proposed model. It was found that “systems” and “personal inclination” factors explain about 49% of the variance related to resistance to enterprise systems. The former factor reveals that the characteristics of the enterprise system to be implemented can lead to resistance to implementation per se, whereas the latter suggests that individuals with an inherent bias to resist change might make the implementation of a new ERP system difficult.     

The impact of the customer relationship management on the organization performance

Customer Relationship Management (CRM) is a very important growing business practice in today's environment. It is used for managing the interaction between a company and its future and current customers. CRM approach's task is analyzing data about the history of customers with a company. It focuses on a way to retain customers, therefore it helps the growth of sales. This leads to improvement of company's business relationship with customers. Current study's goal is to determine how technology, organizational capability, customer orientation, and customer knowledge management influence CRM success. We try to see that how the performance of an organization is affected by the achievement of CRM. For testing the hypotheses, Partial Least Squares Structural Equation Modeling (PLS-SEM) was adopted. Results have indicated that the success of CRM is highly influenced through “information technology use”, also “customer orientation”, “organizational capability”, and “customer knowledge management” are related to CRM success. Finally, along with the future research avenues and limitations, study implications and findings are discussed.     

“金属材料焊接”课堂改革与创新实践

金属材料焊接课程是焊接技术与自动化专业的专业核心课程之一,该文以现代学徒制试点专业建设为契机进行了课程改革,提出以就业为导向的"三引入"教学内容改革、"三联系"的教学方法与教学手段改革以及突出"四个结合"、树立开放的教育教学观。课程改革效果显著,培养了一支优秀的教学团队。     

Technological paradigms and technological trajectories: A suggested interpretation of the determinants and directions of technical change

The procedures and the nature of “technologies” are suggested to be broadly similar to those which characterize “science”. In particular, there appear to be “technological paradigms” (or research programmes) performing a similar role to “scientific paradigms” (or research programmes). The model tries to account for both continuous changes and discontinuities in technological innovation. Continuous changes are often related to progress along a technological trajectory defined by a technological paradigm, while discontinuities are associated with the emergence of a new paradigm. One-directional explanations of the innovative process, and in particular those assuming “the market” as the prime mover, are inadequate to explain the emergence of new technological paradigms. The origin of the latter stems from the interplay between scientific advances, economic factors, institutional variables, and unsolved difficulties on established technological paths. The model tries to establish a sufficiently general framework which accounts for all these factors and to define the process of selection of new technological paradigms among a greater set of notionally possible ones.The history of a technology is contextual to the history of the industrial structures associated with that technology. The emergence of a new paradigm is often related to new “schumpeterian” companies, while its establishment often shows also a process of oligopolistic stabilization.     

Stabilization of carrier-frequency servomechanisms. III. Methods of obtaining required carrier phase-shift

In a servomechanism using a two-phase alternating current control motor, a 90° difference is required in the phases of the carrier-frequency voltages applied to the fixed and control windings. This part describes and compares various methods of obtaining the phase difference.The question of the possibility of a phase-shifting proportional-derivative parallel “T” is answered in the negative, by the result that in any parallel “T” transfer characteristic, if the quadratic factor in the numerator is of the proportional-derivative form at the correct resonant frequency, the amount of phase shift which may be obtained from the remaining portion of the transfer characteristic is less than are tan $\text{(}\text{2}\text{n}\text{)}$, where n is twice the carrier frequency divided by notch width. Thus for values of n high enough to have an appreciable stabilizing effect, the maximum obtainable intrinsic phase shift is negligible.In order to obtain a large phase shift it is necessary to add either a series input or a load impedance to the parallel “T,” or to use a phase-shifting network preceding or following the parallel “T.” Formulae and design charts are given for determination of the values of the components of phase lag networks.The method of calculation of tolerance requirements on the components, in terms of allowable deviation from the correct phase, is illustrated by an example of a phase lag network used in conjunction with a bridge “T” proportional-derivative network.     

Robust stability testing function for a complex interval family of fractional-order polynomials

The robust stability of a family of interval fractional-order systems with complex coefficients is investigated in this study. The concept of “a family of interval fractional-order systems with complex coefficients” means that the characteristic function of a control system can be of both commensurate and non-commensurate orders, the coefficients of the characteristic function can be uncertain parameters, and may be complex numbers. At first, a simple graphical procedure is presented for robust stability analysis. The “robust stability testing function” is then extended to look at the robust conditions. To the best of the authors’ knowledge, no auxiliary function for analyzing the robust stability of the systems under investigation has been introduced until now. Moreover, lower and upper frequency bounds are provided which are useful to improve the computational efficiency of testing the robust stability conditions. Eventually, to verify the results, analytical examples and numerical simulations are provided.     

On the orthogonal factorization and its updating in band- structured matrix computations

A systematic study on the problems encountered in the orthogonal factorization of a general band-structured matrix and its updating subject to a rank-one modification of the original matrix is given. A selective set of efficient algorithms is described. A set of strategies suitable for devising an “optimal” algorithm is also presented with some applications.     

礼物馈赠中的普罗米修斯之惑——以黄金大米全球推广为例

转基因产品黄金大米是一种可救助困顿人群的礼物,却遭遇推广的重重阻力。这是由于:(1)本体层面上,黄金大米尚未有力回应作为增益性基因产品的文化质疑,以及它用解决单纯饥荒的思维难以对抗现实中具体而复杂的制度性饥荒;(2)社会层面,推广者构成的转译网络中不适当的利益觊觎、搭便车行为、新种子带来的经济和规则风险潜在威胁地方农业和农民的利益等。这表明,我们需要辅以多角度的审慎考量,这样才能使黄金大米之类的转基因食品真正发挥造福全人类之礼物功效,消除普罗米修斯之惑。     

An empirical testing of user stereotypes of information retrieval systems

Stereotyping is a technique used in many information systems to represent user groups and/or to generate initial individual user models. However, there has been a lack of evidence on the accuracy of their use in representing users. We propose a formal evaluation method to test the accuracy or homogeneity of the stereotypes that are based on users' explicit characteristics. Using the method, the results of an empirical testing on 11 common user stereotypes of information retrieval (IR) systems are reported. The participants' memberships in the stereotypes were predicted using discriminant analysis, based on their IR knowledge. The actual membership and the predicted membership of each stereotype were compared. The data show that “librarians/IR professionals” is an accurate stereotype in representing its members, while some others, such as “undergraduate students” and “social sciences/humanities” users, are not accurate stereotypes. The data also demonstrate that based on the user's IR knowledge a stereotype can be made more accurate or homogeneous. The results show the promise that our method can help better detect the differences among stereotype members, and help with better stereotype design and user modeling. We assume that accurate stereotypes have better performance in user modeling and thus the system performance.Limitations and future directions of the study are discussed.     

Competing roles of intention and habit in predicting behavior: A comprehensive literature review,synthesis, and longitudinal field study

Achieving the promised benefits of a new technology is closely tied to its sustained use. The dominant approach has been to predict use based on behavioral intention. Central to this approach is the assumption that use comes from conscious decision making, resulting from “thinking”, “reflecting”, and “cognition”. However, related work has shown that, over time and with increasing experience, use becomes habitual (routine, automatic) and when this happens, it is not subject to conscious decision making. This paper extends the technology adoption and use literature by testing the relative effects of intention and habit as determinants of use. We conducted a longitudinal field study over the period of one year, with 4 points of measurement in 7 organizations among 1235 users, to examine the effects of intention and habit from the formative stage of experience with a new technology through to an established, stable stage. The results provided strong support for habit as a predictor of use, especially over time, as use became well-rehearsed, and habit was a stronger determinant of use than intention was. In fact, habit dominates intention as a predictor of use, as experience increases. We discuss key implications for research and practice.     

基于“睡美人”文献识别的高校学术论文价值挖掘方法研究——以东北大学为例

[目的/意义]研究“睡美人”文献的识别方法,对尽早发现重要科技成就及其发明人、加快科技成果转化以及完善学术评价方法等均具有重要意义。[方法/过程]针对高校学术论文成果评价这一特定场景,提出“先客观指标粗筛、后多维参数细选”的研究思路,组合使用K值算法和三指标法,对东北大学发表于Web of Science核心合集的论文样本集进行了“睡美人”文献挖掘的实证研究。[结果/结论]该方法共识别出12篇“睡美人”文献,并对其被引特征、期刊特征、睡眠特征、内容特征等因素进行了分析。实获数据处理结果表明了该方法的有效性,相关研究方法和结果可对东北大学学术论文评价提供重要参考。     

CC-Qual: A holistic scale to assess customer perceptions of service quality of collaborative consumption services

The paper defines and validates a scale—CC-Qual—to assess the quality of services provided through a Collaborative Consumption (CC) model.The authors have borrowed a set of items arranged in eight dimensions from the literature on CC. A panel of selected practitioners (seven CEOs of CC companies) assisted in the design of the questionnaire, which was launched in June 2018. A sample of 127 questionnaires was used for exploratory factor analysis. A second sample of 301 users was used for confirmatory analysis using EQS 6.4 software.A scale of 21 items gathered under five dimensions is proposed. Accordingly, the perceived quality in CC is composed of five dimensions: three of them related to the interaction with the platform (“site organization”, “platform responsiveness and agility” and “legal protection and trustworthiness”), another related to the perceived quality of the peer service supplier (“peer service provider”) and the last one to assess the encounters with other consumers and with the person who provides the service (“social interaction”).This study provides a useful measure for the assessment of the perceived quality of CC services, regardless of the activity sector. This instrument might assist managers for both assessing and benchmarking. The instrument also provides independent and reliable information for customers.     

社会地位、政府角色认知与公共服务满意度--基于 CGSS2013的结构方程分析

利用中国综合社会调查（CGSS）2013数据,构建公共服务满意度的结构方程模型。对全国5266个居民样本分析发现,民众社会地位越高,越倾向于“大政府”。而在控制社会地位和公共服务质量感知的情况下,民众赞同“大政府”的倾向越强,其公共服务满意度越高。在此基础上提出加强对民众思想观念的塑造和引导可以有效提高公共服务满意度,降低政府公共服务供给压力。     

The new production of legitimacy: STI policy discourses beyond the contract metaphor

Science, technology and innovation (STI) policy is borne by a set of historically contingent concepts, models, and metaphors. From around 1950 to 1980, its language was dominated by the contract metaphor and the linear model of innovation, both of which have catered for beliefs in stability, orderliness, and distinct social roles for scientists and policymakers. While prominent new models of the 1990s (mode 2, post-normal science, triple helix) had challenged the old contract metaphor, they remained experts’ brainchildren. After 2000, in contrast, we observe the emergence and pluralization of several new and powerful concepts. Building on conceptual history and cognitive linguistics, we analyze three of these new concepts: “frontier research,” “grand challenges,” and “responsible research and innovation” (RRI). Whereas the “frontier” and “grand challenges” convey many layered historical meanings, a distinct metaphorical appeal, and have become popularized beyond expert’s communities, the RRI discourse, though the most ambitious one, has not yet shaken off its roots in the bureaucratic structures of the European Commission. Finally, we discuss which conceptual and metaphorical properties enable the career of STI policy discourses in the 21st century.