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1.
《Ergonomics》2012,55(9):832-859
The use of dedicated bus shoulders is a key method for implementing bus rapid transit (BRT) in areas that do not have the space for additional infrastructure. However, the narrow width of the bus shoulder and the need to anticipate traffic hazards in the adjacent lane can both be significant stressors for bus drivers. Bus driver mental workload and stress in response to these conditions should be a significant concern both for operational safety and driver health. This pilot study evaluated the potential stressors of traffic density and shoulder width in the context of an express BRT service in a large US metropolitan area. In addition, the study considered the potential role of a prototype lane support system (LSS) to support vehicle control within the narrow shoulder boundaries. Ten experienced bus drivers drove an actual route with an instrumented bus equipped with and without LSS. Self-reported effort was recorded along with performance measures of speed and position control relevant to mobility and safety objectives. Bus drivers did note stressors in the BRT environment and the prototype LSS. However, the use of the shoulder during high-density traffic conditions did improve mobility. Moreover, the LSS did enhance safety on the shoulder when there was high-density traffic in the adjacent lane. However, there was no evidence that the LSS reduced bus driver workload while operating in the narrow shoulder. Future research should consider the impact of BRT operations and support systems on bus driver mental workload and stress, and support the deployment of such devices for bus operations on shoulders during high traffic volumes. 相似文献
2.
张晓杰 《自动化与仪器仪表》2008,(1):60-62
介绍了几种最新的测量仪器控制系统总线技术,分析了其主要性能、特点以及给测量仪器和控制系统带来的影响,探讨了GPIB与其它总线组合使用时仪器系统的未来发展. 相似文献
3.
The information fusion field has recently been attracting a lot of interest within the scientific community, as it provides, through the combination of different sources of heterogeneous information, a fuller and/or more precise understanding of the real world than can be gained considering the above sources separately. One of the fundamental aims of computer systems, and especially decision support systems, is to assure that the quality of the information they process is high. There are many different approaches for this purpose, including information fusion. Information fusion is currently one of the most promising methods. It is particularly useful under circumstances where quality might be compromised, for example, either intrinsically due to imperfect information (vagueness, uncertainty, …) or because of limited resources (energy, time, …). In response to this goal, a wide range of research has been undertaken over recent years. To date, the literature reviews in this field have focused on problem-specific issues and have been circumscribed to certain system types. Therefore, there is no holistic and systematic knowledge of the state of the art to help establish the steps to be taken in the future. In particular, aspects like what impact different information fusion methods have on information quality, how information quality is characterised, measured and evaluated in different application domains depending on the problem data type or whether fusion is designed as a flexible process capable of adapting to changing system circumstances and their intrinsically limited resources have not been addressed. This paper aims precisely to review the literature on research into the use of information fusion techniques specifically to improve information quality, analysing the above issues in order to identify a series of challenges and research directions, which are presented in this paper. 相似文献
4.
周前柏 《计算机测量与控制》2015,23(11):16-16
电动静液作动器是飞机操纵系统的关键部件,要求有较好的速度平稳性。系统内存在泄漏非线性和摩擦非线性等影响速度平稳性的因素。滑模控制可以有效抑制系统内非线性因素的影响,但是由于抖振现象的存在限制了速度平稳性的进一步提升。针对固定切换增益的滑模控制方法的不足,提出一种基于变结构滤波器的自适应滑模控制方法。采用变结构滤波器估计系统状态信息,估计的系统状态信息用于构建滑模面,采用自适应切换增益来导出控制率,有效减小了抖振幅度。仿真结果证明了自适应滑模控制方法的有效性,采用这种方法提高了电动静液作动器的速度平稳性。 相似文献
5.
A new approach to clamping workpieces for the machining process has been developed. The new approach is based on the identification of the workpiece stiffness, during the machining process, which enables the fixturing system to determine whether the clamping force should be changed. Using this approach, a three-fingered intelligent automated flexible fixturing system for planar objects has been successfully designed and implemented. The conventional and traditional clamping methods use a hydraulic vise to clamp workpieces with a fixed amount of clamping forces. This often causes the workpieces to deform under such force, thus contributing to machining error. It is therefore desirable to control the clamping force according to the progress of the machining process. The implementation of this approach to the three-fingered automated flexible fixturing system enhances the system’s ability to achieve intelligent clamping force control and deal with abnormal machining, thus making the system intelligent. A thin ring-shaped workpiece was successfully used as an example to demonstrate the feasibility and validity of this approach. It also demonstrates that the developed system can be used in the highly automated manufacturing system of the future. 相似文献
6.
Marcantonio Catelani Author VitaeLorenzo CianiAuthor Vitae Valeria L. Scarano Author VitaeAlessandro BacioccolaAuthor Vitae 《Computer Standards & Interfaces》2011,33(2):152-158
Software plays an increasingly important role in complex systems, especially for high-tech applications involved in important fields, such as transportation, financial management, communication, biomedical applications and so on. For these systems, performances such as efficient operation, fault tolerance, safety and security have to be guaranteed by the software structure, whose quality in use is assuming a growing importance from the industrial point of view. The basic problem is that the complexity of the task which software has to perform has often grown more quickly than hardware. In addition, unlike hardware, software cannot break or wear out, but can fail during its life cycle (dynamic defects) [1]. Software problems, essentially, have to be solved with quality assurance tools such as configuration management, testing procedures, quality data reporting systems and so on [2]. In this context, the paper proposes a new approach concerning the automated software testing as an aid to maximize the test plan coverage within the time available and also to increase software reliability and quality in use [3]. In this paper a method which combines accelerated automated tests for the study of software regression and memory overflow will be shown, in order to guarantee software with both a high quality level and a decrease of the testing time. The software will be tested by using test sequences reproducing the actual operating conditions and accelerated stress level. Moreover the research wishes to define some parameters of the software life and to show the generality of the proposed technique. 相似文献
7.
Cell formation is the first step in the design of cellular manufacturing systems. In this study, an efficient tabu search algorithm based on a similarity coefficient is proposed to solve the cell formation problem with alternative process routings and machine reliability considerations. In the proposed algorithm, good initial solutions are first generated and later on improved by a tabu search algorithm combining the mutation operator and an effective neighborhood solution searching mechanism. Computational experiences from test problems show that the proposed approach is extremely effective and efficient. When compared with the mathematical programming approach which took three hours to solve problems, the proposed algorithm is able to produce optimal solutions in less than 2 s. 相似文献
8.
With the development of intelligent manufacturing, production scheduling and preventive maintenance are widely applied in industry to enhance production efficiency and machine reliability. Therefore, according to the different processing states and the physical degradation phenomena of the machine, this paper proposes an accurate maintenance (AM) model based on reliability intervals, which have different maintenance activities in diverse intervals and overcome the shortcoming of the single reliability threshold maintenance model used in the past. Combining the flexible job-shop scheduling problem (FJSP), an integrated multiobjective optimization model is established with production scheduling and accurate maintenance. To strengthen the ability of the evolutionary algorithm to solve the presented model/problem, we propose a novel genetic algorithm, named the approximate nondominated sorting genetic algorithm III (ANSGA-III), which is inspired by NSGA-III. To improve the performance of the Pareto dominance principle, the local search, the elite storage for the original algorithm, the approximate dominance principle, the variable neighborhood search, and the elite preservation strategy are proposed. Then, we employ a scheduling example to verify and evaluate the availability of the above three improved operations and the proposed algorithm. Next, we compare ANSGA-III against five recently proposed algorithms, representing the state-of-the-art on similar problems. Finally, we apply ANSGA-III to solve the integrated optimization model, and the results reveal that the machine can maintain higher availability and reliability when compared to other models in our experiments. Consequently, the superiority of the proposed model based on accurate maintenance of reliability intervals is demonstrated, and the optimal reliability threshold between the yellow and red areas is found to be 0.82. 相似文献
9.
This paper analyses driver trust and performance when using adaptive cruise control (ACC) in a situation involving a truck cutting into the lane in front of the ACC-equipped vehicle. The study was carried out using a mini driving simulator and a simulated ACC whose reference speed and time headway (THW) were preset to 130 km/h and 1.5 s, respectively. Questionnaires were used to analyse driver trust. Two kinds of drivers emerge from the analysis of driver behaviour during the cut-in situation: drivers who reclaimed control from the ACC before the device began to regulate the THW with regard to the truck, and drivers who braked after the device had begun its regulation. The latter demonstrated a higher level of trust in the ACC device itself while the former had a higher level of trust in the cooperation with the device. These findings are discussed in terms of over-reliance and well-calibrated trust. 相似文献
10.
《The Journal of Strategic Information Systems》2006,15(1):29-50
The contribution of IT to business performance has been studied from two main perspectives: a ‘strategy as positioning perspective,’ which underlines a market power imperative, and a resource-based view perspective, which conceptualizes the enterprise as a ‘bundle of unique resources.’ The objective of the present study is to improve our understanding of the contribution of IT to firm performance in building upon the complementarity between the two perspectives. To do so, a model proposed by [Spanos, Y.E., Lioukas, S. 2001. An examination into the causal logic of rent generation: contrasting Porter's competitive strategy framework and the resource-based perspective. Strategic Management Journal 22(10), 907–934], which comprises both a competitive strategy framework and the resource-based perspective was adapted to reflect the role played by IT. More precisely, the model encapsulates the effects of both IT support for business strategy and IT support for firm assets on firm performance. To test the model, a survey of 96 small- and medium-sized enterprises (SME) was conducted. 相似文献
11.
Human Computer Interaction (HCI) is a research field which aims to improve the relationship between users and interactive computer systems. A main objective of this research area is to make the user experience more pleasant and efficient, minimizing the barrier between the users׳ cognition of what they want to accomplish and the computer׳s understanding of the user׳s tasks, by means of user-friendly, useful and usable designs. A bad HCI design is one of the main reasons behind user rejection of computer-based applications, which in turn produces loss of productivity and economy in industrial environments.In the eHealth domain, user rejection of computer-based systems is a major barrier to exploiting the maximum benefit from those applications developed to support the treatment of diseases, and in the worst cases a poor design in these systems may cause deterioration in the clinical condition of the patient. Thus, a high level of personalisation of the system according to users׳ needs is extremely important, making it easy to use and contributing to the system׳s efficacy, which in turn facilitates the empowerment of the target users. Ideally, the content offered through the interactive sessions in these applications should be continuously assessed and adapted to the changing condition of the patient. A good HCI design and development can improve the acceptance of these applications and contribute to promoting better adherence levels to the treatment, preventing the patient from further relapses.In this work, we present a mechanism to provide personalised and adaptive daily interactive sessions focused on the treatment of patients with Major Depression. These sessions are able to automatically adapt the content and length of the sessions to obtain personalised and varied sessions in order to encourage the continuous and long-term use of the system. The tailored adaptation of session content is supported by decision-making processes based on: (i) clinical requirements; (ii) the patient’s historical data; and (iii) current responses from the patient. We have evaluated our system through two different methodologies: the first one performing a set of simulations producing different sessions from changing input conditions, in order to assess different levels of adaptability and variability of the session content offered by the system. The second evaluation process involved a set of patients who used the system for 14–28 days and answered a questionnaire to provide feedback about the perceived level of adaptability and variability produced by the system. The obtained results in both evaluations indicated good levels of adaptability and variability in the content of the sessions according to the input conditions. 相似文献
12.
The bursting phenomenon in a Nussbaum-type regulator is discussed. Its cause is associated with some properties of the equilibrium manifold. A σ-modification factor is introduced, and the resulting equilibrium set is completely characterized using linearization techniques. Local robustness against bounded disturbances is proved by Malkin's Theorem, and verified by simulation. 相似文献
13.
14.
《Journal of Visual Languages and Computing》2014,25(4):346-362
The flexibility offered by dynamically typed programming languages has been appropriately used to develop specific scenarios where dynamic adaptability is an important issue. This has made some existing statically typed languages gradually incorporate more dynamic features to their implementations. As a result, there are some programming languages considered hybrid dynamically and statically typed. However, these languages do not perform static type inference on a dynamically typed code, lacking those common features provided when a statically typed code is used. This lack is also present in the corresponding IDEs that, when a dynamically typed code is used, do not provide the services offered for static typing. We have customized an IDE for a hybrid language that statically infers type information of dynamically typed code. By using this type information, we show how the IDE can provide a set of appealing services that the existing approaches do not support, such as compile-time type error detection, code completion, transition from dynamically to statically typed code (and vice versa), and significant runtime performance optimizations. We have evaluated the programmer׳s performance improvement obtained with our IDE, and compared it with similar approaches. 相似文献
15.
Taylor polynomial Approximation and Adaptive Passivity‐Based Control Applied to the Level Regulation of a Conical Tank
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Juan Carlos Travieso‐Torres Manuel A. Duarte‐Mermoud Orlando Beytía‐Cancino 《Asian journal of control》2017,19(5):1722-1730
The techniques of Taylor polynomial approximation (TPA) and adaptive passivity‐based controller (APBC) are combined in this study and applied to the level regulation of a conical tank. The design and comparative experimental results with a classical PI controller are presented. After combining these two approaches a robust adaptive controller named TPA–APBC, which is simpler than the classical APBC and PI controller, is obtained. This new TPA–APBC preserves the stability of the overall system after assuming that the nonlinear system is unknown and that it can be suitably represented by a first‐order linear model with unknown parameters. 相似文献
16.
This work presents modeling, driving and classical speed control techniques for the switched reluctance motor. The aim is to improve the computational model, the control response and the machine efficiency. A parametric regression model was used to find the inductance profile of the switched reluctance motor and from the new inductance profile model. The drive and control techniques are shown: (i) with speed control acting on the excitation voltage and fixed switching angles, (ii) with speed control acting on the switching angles and fixed excitation voltage and (iii) with speed control acting on the excitation voltage, in this case, with dynamic switching angles and controller parameters. The inductance profile is represented by expression and inserted into the machine computer model, allowing greater precision and low computational cost. The speed control acting on the excitation voltage with dynamic controller parameters and dynamic switching angles allowed: (i) shorter response time for a wide range of control, (ii) higher efficiency, (iii) low computational cost and (iv) simplified implementation and maintenance. The techniques proposed in this work obtained precision of the computational model with respect to the system (in workbench) and optimized parameters in a wide range of the speed control, allowing an improvement of switched reluctance motor efficiency. 相似文献
17.
付学敏 《网络安全技术与应用》2014,(1):194-195
我国正处于一个信息技术不断发展,科技水平不断提高的阶段。在这样的社会背景下,多媒体技术越来越广泛地应用于社会的各个环节,在高级职业技术学校的英语教学中也不例外。如何能够借助计算机多媒体技术来提高高级职业技术学校的英语听说教学水平,成为了各个高职学校关注的重点。合理利用计算机多媒体资源能够实现学生听说能力的提高,丰富课堂。本文将围绕该问题展开探究。 相似文献
18.
董巍 《网络安全技术与应用》2014,(11):170-170
现在的社会是信息社会,大范围的信息交流需要借助信息技术技术的运用。现在的高校学习越来越重视了信息技术的学习,信息技术教学是高校为社会输送信息技术人才的重要的方式,在现在的高校信息技术教学中,互助教学是信息技术课堂上常用的教学方式。本文将从信息技术课堂上互助教学的必要性出发,分析互助教学运用中应注意的问题,以及互助教学在高校信息技术教学如何运用。 相似文献
19.
Dave Barker-Plummer 《Journal of Automated Reasoning》1992,8(3):311-344
A major outstanding problem in automated theorem proving research is determining the appropriate use of definitions and previously
proved theorems within a proof. Presenting the theorem prover with only the formulae that are necessary for the proof might
be viewed as ‘cheating’ and requires that the user prove the theorem ahead of time. In real world applications of theorem
proving, this is almost certain to be infeasible. On the other hand providing the prover with all formulae that might be relevant
rapidly swamps the prover with unnecessary information. A technique for the selective retrieval of formulae based on features
of those formulae and the conjecture at hand is required to solve this problem.
In this paper I describe an abstraction-based technique which addresses this problem. Implicit hypotheses such as definitions,
axioms and previously proved theorems are stored in a database which may be accessed by a heuristic rule of inference calledgazing. Before accessing this database the gazing rule plans the use of these formulae in a hierarchy of abstraction spaces. When
the planning phase is complete, the system can use the indicated formulae with some confidence that they are relevant to the
proof.
Since the technique is abstraction-based, no guarantee that the plant will be eventually applicable or successful can be made.
However, because the plans are built by considering increasing amounts of detail, the number of ways in which the application
of a plan can fail is limited. Plan failures may be ‘patched’ in a uniform way. 相似文献
20.
Nicolas Michinov Éric Anquetil Estelle Michinov 《Journal of Computer Assisted Learning》2020,36(6):1026-1037
Peer Instruction is an active learning method widely used in higher education, whereby students answer a series of questions twice, once before and once after peer discussion. There is an ongoing debate as to whether a collective feedback should be given after the students' initial answer, and if so, how the frequently observed group conformity can be avoided. This study examined whether guiding on the use of this feedback can reduce group conformity and improve learning using an interactive learning environment to administer a new type of quiz using graphics, and delivering collective feedback to the whole class in a novel heatmap format. In the experimental group, the teacher told the students that the answer indicated by the heatmap was not necessarily the correct one; this information was not given to students in the control group. Results revealed that guided students were less likely to adopt the (incorrect) majority answer than the non-guided students, and consequently, they were more likely to improve their learning by reaching an agreement about the correct answer through discussion with their peers. These findings suggest that guiding students in their use of collective feedback may have a crucial role in Peer Instruction. 相似文献