数据中心计算环境应用承载能力评价

随着新型计算服务模式在数据中心的普及,针对如何有效评价其承载能力的问题,提出一种新的应用承载能力评价体系和评价模型,具体分析了网络、计算资源对服务环境的影响度,并给出了实例分析。实例分析结果表明,新的评价体系和评价模型可以有效评估计算服务模式对各类信息服务系统部署运行的应用承载能力,进而提升信息服务保障整体效益。     

Acoustic environment as an indicator of social and physical context

Acoustic environments provide many valuable cues for context-aware computing applications. From the acoustic environment we can infer the types of activity, communication modes and other actors involved in the activity. Environmental or background noise can be classified with a high degree of accuracy using recordings from microphones commonly found in PDAs and other consumer devices. We describe an acoustic environment recognition system incorporating an adaptive learning mechanism and its use in a noise tracker. We show how this information is exploited in a mobile context framework. To illustrate our approach we describe a context-aware multimodal weather forecasting service, which accepts spoken or written queries and presents forecast information in several forms, including email, voice and sign languages.

Hands-free administration of subjective workload scales: Acceptability in a surgical training environment

Introduction

Subjective workload measures are usually administered in a visual-manual format, either electronically or by paper and pencil. However, vocal responses to spoken queries may sometimes be preferable, for example when experimental manipulations require continuous manual responding or when participants have certain sensory/motor impairments. In the present study, we evaluated the acceptability of the hands-free administration of two subjective workload questionnaires - the NASA Task Load Index (NASA-TLX) and the Multiple Resources Questionnaire (MRQ) - in a surgical training environment where manual responding is often constrained.

Method

Sixty-four undergraduates performed fifteen 90-s trials of laparoscopic training tasks (five replications of 3 tasks - cannulation, ring transfer, and rope manipulation). Half of the participants provided workload ratings using a traditional paper-and-pencil version of the NASA-TLX and MRQ; the remainder used a vocal (hands-free) version of the questionnaires. A follow-up experiment extended the evaluation of the hands-free version to actual medical students in a Minimally Invasive Surgery (MIS) training facility.

Results

The NASA-TLX was scored in 2 ways - (1) the traditional procedure using participant-specific weights to combine its 6 subscales, and (2) a simplified procedure - the NASA Raw Task Load Index (NASA-RTLX) - using the unweighted mean of the subscale scores. Comparison of the scores obtained from the hands-free and written administration conditions yielded coefficients of equivalence of r = 0.85 (NASA-TLX) and r = 0.81 (NASA-RTLX). Equivalence estimates for the individual subscales ranged from r = 0.78 (“mental demand”) to r = 0.31 (“effort”). Both administration formats and scoring methods were equally sensitive to task and repetition effects. For the MRQ, the coefficient of equivalence for the hands-free and written versions was r = 0.96 when tested on undergraduates. However, the sensitivity of the hands-free MRQ to task demands (η_partial² = 0.138) was substantially less than that for the written version (η_partial² = 0.252). This potential shortcoming of the hands-free MRQ did not seem to generalize to medical students who showed robust task effects when using the hands-free MRQ (η_partial² = 0.396). A detailed analysis of the MRQ subscales also revealed differences that may be attributable to a “spillover” effect in which participants’ judgments about the demands of completing the questionnaires contaminated their judgments about the primary surgical training tasks.

Conclusion

Vocal versions of the NASA-TLX are acceptable alternatives to standard written formats when researchers wish to obtain global workload estimates. However, care should be used when interpreting the individual subscales if the object is to make comparisons between studies or conditions that use different administration modalities. For the MRQ, the vocal version was less sensitive to experimental manipulations than its written counterpart; however, when medical students rather than undergraduates used the vocal version, the instrument’s sensitivity increased well beyond that obtained with any other combination of administration modality and instrument in this study. Thus, the vocal version of the MRQ may be an acceptable workload assessment technique for selected populations, and it may even be a suitable substitute for the NASA-TLX.     

Learning about evaluation and assessment: teacher's use of folksonomies and ontologies in an online narrative environment

Building ontology in the domain of human sciences can be a difficult process because of the different meanings given to the same key concepts in these disciplines: in fact, shared meaning is an important element in knowledge construction between members of a community. In this paper, we propose a participatory social environment called ‘EduOntoWiki’ where academic experts in the field of educational sciences develop lightweight ontologies that members of multiple communities of practice (teachers, trainers, etc.) can modify and integrate using a folksonomic and storytelling approach. In this way, real‐life narrative contexts become precious ‘tagged’ alternative representations that can contribute to the ontology construction process. Experience of the environment gave possible indications regarding its use in teachers' training courses and as a useful tool to discuss evaluation and assessment issues in teachers' professional practice.     

复杂电磁环境雷达新型威胁信号建模与仿真

复杂电磁环境中雷达新型威胁信号相对传统威胁信号具有更强的相干性和隐蔽性,信号环境对雷达装备构成较大威胁。针对目前对该类环境信号干扰机理和数学模型欠缺系统性研究的问题,分析了环境的组成要素,并对典型的信号样式建立了数学模型。最后,研制开发了雷达信号环境全数字仿真模拟系统,在该系统上实现了信号模型的仿真验证。仿真结果表明了模型的合理性和有效性。     

WESTT (workload, error, situational awareness, time and teamwork): an analytical prototyping system for command and control

Modern developments in the use of information technology within command and control allow unprecedented scope for flexibility in the way teams deal with tasks. These developments, together with the increased recognition of the importance of knowledge management within teams present difficulties for the analyst in terms of evaluating the impacts of changes to task composition or team membership. In this paper an approach to this problem is presented that represents team behaviour in terms of three linked networks (representing task, social network structure and knowledge) within the integrative WESTT software tool. In addition, by automating analyses of workload and error based on the same data that generate the networks, WESTT allows the user to engage in the process of rapid and iterative “analytical prototyping”. For purposes of illustration an example of the use of this technique with regard to a simple tactical vignette is presented.     

Mental workload and cognitive task automaticity: an evaluation of subjective and time estimation metrics

Abstract

The evaluation of mental workload is becoming increasingly important in system design and analysis. The present study examined the structure and assessment of mental workload in performing decision and monitoring tasks by focusing on two mental workload measurements: subjective assessment and time estimation. The task required the assignment of a series of incoming customers to the shortest of three parallel service lines displayed on a computer monitor. The subject was either in charge of the customer assignment (manual mode) or was monitoring an automated system performing the same task (automatic mode). In both cases, the subjects were required to detect the non-optimal assignments that they or the computer had made. Time pressure was manipulated by the experimenter to create fast and slow conditions. The results revealed a multi-dimensional structure of mental workload and a multi-step process of subjective workload assessment. The results also indicated that subjective workload was more influenced by the subject's participatory mode than by the factor of task speed. The time estimation intervals produced while performing the decision and monitoring tasks had significantly greater length and larger variability than those produced while either performing no other tasks or performing a well practised customer assignment task. This result seemed to indicate that time estimation was sensitive to the presence of perceptual/cognitive demands, but not to response related activities to which behavioural automaticity has developed.     

Seeing through the mist: an evaluation of an iteratively designed head-up display,using a simulated degraded visual environment,to facilitate rotary-wing pilot situation awareness and workload

Cognition, Technology & Work - Degraded visual conditions present a great challenge to rotary-wing aircraft. These conditions can obscure cues used to interpret speed, location and approach....     

LoI: Efficient relevance evaluation and filtering for distributed simulation

In large-scale distributed simulation, thousands of objects keep moving and interacting in a virtual environment, which produces a mass of messages. High level architecture (HLA) is the prevailing standard for modeling and simulation. It specifies two publish-subscribe mechanisms for message filtering: class-based and value-based. However, the two mechanisms can only judge whether a message is relevant to a subscriber or not. Lacking of the ability to evaluate the relevance, all relevant messages are delivered with the same priority even when congestion occurs. It significantly limits the scalability and performance of distributed simulation. Aiming to solve the relevance evaluation problem, speed up message filtering, and filter more unnecessary messages, a new relevance evaluation mechanism Layer of Interest (LoI) was proposed by this paper. LoI defines a relevance classifier based on the impact of spatial distance on receiving attributes and attribute values. An adaptive publish-subscribe scheme was built on the basis of LoI. This scheme can abandon most irrelevant messages directly. Run-time infrastructure (RTI) can also apply congestion control by reducing the frequency of sending or receiving object messages based on each objects’ LoI. The experiment results verify the efficiency of message filtering and RTI congestion control. Supported by the National Basic Research Program of China (Grant No. 2009CB320805), the National Natural Science Foundation of China (Grant No. 60603084), and the National High-Tech Research & Development Program of China (Grant No. 2006AA01Z331)     

无线传感器网络关键技术及其仿真平台分析

对无线传感器网络技术特点进行了研究,分析了无线传感器网络研究的技术难点和重点.针对目前出现的各种仿真平台,如OPNET、OMNET++、NS2、TOSSIM等,分析研究了其技术特点并进行归纳性分类和概括,阐述了无线传感器网络仿真的重点评估指标,更好地推动无线传感器网络仿真研究的发展.     

Way-finding during a fire emergency: an experimental study in a virtual environment

The way-finding behaviour and response during a fire emergency in a virtual environment (VE) was experimentally investigated. Forty participants, divided into two groups, were required to find the emergency exit as soon as possible in a virtual hotel building because of a fire escape demand under condition 1 (VE without virtual fire, control group) and condition 2 (VE with virtual fire, treatment group). Compared to the control group, the treatment group induced significantly higher skin conductivity and heart rate, experienced more stress, took longer time to notice the evacuation signs, had quicker visual search and had a longer escape time to find the exit. These results indicated that the treatment condition induced higher physiological and psychological stress, and had influenced the escape behaviour compared to the control group. In practice, fire evacuation education and fire evacuation system design should consider the response characteristics in a fire emergency.     

Navigation in desktop virtual environments: an evaluation and recommendations for supporting usability

Virtual reality (VR) can provide useful tools for a variety of applications. However, for these tools to be effective, they must be easy to use. In virtual environments (VEs), usability is impaired by poorly designed navigation systems. Insufficient realism and missing physiological orientation and motion cues impair spatial learning in desktop VEs. Capabilities for navigation in a VE are far more varied than in reality; so much greater flexibility can be offered, but designing VEs with too many options can overwhelm users. To assist designers in building effective, usable navigation systems for VEs, navigation techniques must be evaluated to identify which features actually support users in accomplishing their tasks and which features create unnecessary problems.This study evaluates navigation in two different VEs to develop recommendations for the design of navigation systems in desktop VEs. The study consists of an objective assessment of navigation control dynamics, a guideline-based evaluation and a review of data collected during two experimental studies. The findings indicate that real-world constraints, specialised navigation techniques and feedback regarding location and direction of travel are needed to support navigation in desktop VEs.     

Quality management and the work environment: an empirical investigation in a public sector organization

The integration of quality management initiatives, particularly total quality management (TQM), and ergonomics has received increasing attention from scholars and practitioners. Above all, the question of how TQM programs relate to ergonomic aspects of organizational design and culture is at the center of this discussion. This study examines how elements of a "typical", Deming-inspired, TQM program in the public sector interact with the work environment. Elements of the TQM program were defined and measured using the Malcom Baldridge Award criteria. The specific elements examined were "Management Support of Quality", "Information and Analysis", "Human Resources", "Processes and Quality Results", and "Customer Focus and Satisfaction". The relationship between these TQM elements and the work environment were defined through five separate hypotheses. The work environment was described by the constructs "Supervisor Support", "Task Clarity", "Task Orientation", and "Innovation". Data were obtained through survey questionnaires administered to employees of four departments in a municipal government organization. Results supported three of the hypotheses, but produced some unanticipated outcomes with regard to the other two. Namely, "Management Support of Quality" was significantly related to "Supervisor Support", "Task Orientation", "Task Clarity" and "Innovation"; "Human Resources" was significantly related to "Supervisor Support"; "Processes and Quality Results" was significantly related to "Task Orientation" and "Innovation". Contrary to predicted "Information and Analysis" was negatively related to "Innovation", and "Customer Focus" was unrelated to any of the outcome variables. The relationships between these TQM elements and work environment dimensions are discussed. Implications for TQM and ergonomic practice are analyzed, and directions for future research proposed.     

Behavioural,physiological and psychological responses of passengers to the thermal environment of boarding a flight in winter

In practice, passengers actively respond to the thermal environment when they board an aircraft in winter, which is not considered in the current standards. In this study, the behavioural, physiological and psychological responses to the thermal environment were examined at 22 °C (with 68 subjects), 20 °C and 26 °C (with 32 subjects). The results showed that the three air temperature levels had significant effect on nozzle usage and clothing adjustment behaviours, surface skin temperature, and thermal sensation vote (TSV). The walking/waiting states prior to boarding the aircraft cabin had a significant effect on the proportion of jacket removal, TSV and thermal comfort vote. After 10 min in the aircraft cabin, the subjects maintained their comfort in a wider range of the thermal environment when the behavioural adjustments existed compared to when they did not. Thus, a suggestion was made for behavioural adjustments to be provided in aircraft cabins.

Practitioner Summary: Experimental investigation of human responses was conducted in an aircraft cabin. Analysis showed that the subjects maintained their comfort in a wider range of the thermal environment when the behavioural adjustments existed compared to when they did not. Thus, a suggestion was made for behavioural adjustments to be provided in aircraft cabins.     

基于INTERNET的成本效益评估模型与瞬时决策

介绍了基于INTERNET的成本效益评估模型,提出多BOM策略。并通过在一个ERP系统的开发实施中将评估模型与多BOM策略相结合的应用实例分析,提出了瞬时决策概念,对于以多品种、小批量为重要特点的塑胶及精细化工行业的生产经营管理决策有显著的指导意义。论文最后总结了化工过程系统实现信息化的一些基本原则与方法。     

The use of problem solving skills in computer-aided instruction: an evaluation

Abstract When computer programs are designed to elicit problem solving skills by the user, this basic premise should be tested in an objective manner. The Health and Fitness Assessment program was evaluated as an interactive program with a substantial emphasis on the problem solving process. A method of analysis known as protocol analysis was used to demonstrate that 72% of the interpretive statements made by users verified the use of higher level mental functions to interact with the computer. Other evaluative data aided in improving the design of the program.     

Occupational stress in submariners: The impact of isolated and confined work on psychological well-being

This study aimed to identify work-related and personal factors associated with occupational stress in submariners. Work and well-being questionnaires were distributed to 219 male submariners (mean age 34 years), as part of a larger cohort study involving a stratified sample of 4951 Royal Navy (RN) personnel. The stress rate in submariners was 40%; significantly higher than the stress rate in the general RN, although once demographic factors were controlled for in a matched control sample, this difference was no longer significant. A summary model accounted for 49% of the variance in submariner stress, with key differences emerging between the occupational factors associated with stress in submariners and in the general RN. The longitudinal nature of this study permits stress in submariners to be monitored over 5 years, which will provide valuable insights into the chronicity of stress in this specialised occupational group.

Statement of Relevance: This paper contributes to the current literature on the negative impact of working in isolated conditions. It is demonstrated that occupational stress in submarines can be partially explained using current theories of stress in the workplace. However, the constraints of a restricted environment introduce additional factors which can also be associated with occupational stress.     

Product concept evaluation and selection using data mining and domain ontology in a crowdsourcing environment

For product design and development, crowdsourcing shows huge potential for fostering creativity and has been regarded as one important approach to acquiring innovative concepts. Nevertheless, prior to the approach could be effectively implemented, the following challenges concerning crowdsourcing should be properly addressed: (1) burdensome concept review process to deal with a large amount of crowd-sourced design concepts; (2) insufficient consideration in integrating design knowledge and principles into existing data processing methods/algorithms for crowdsourcing; and (3) lack of a quantitative decision support process to identify better concepts. To tackle these problems, a product concept evaluation and selection approach, which comprises three modules, is proposed. These modules are respectively: (1) a data mining module to extract meaningful information from online crowd-sourced concepts; (2) a concept re-construction module to organize word tokens into a unified frame using domain ontology and extended design knowledge; and (3) a decision support module to select better concepts in a simplified manner. A pilot study on future PC (personal computer) design was conducted to demonstrate the proposed approach. The results show that the proposed approach is promising and may help to improve the concept review and evaluation efficiency; facilitate data processing using design knowledge; and enhance the reliability of concept selection decisions.     

Administrative evaluation and public sector reform: an analytic hierarchy process approach

The objective of this paper is to propose a rational approach to administrative evaluation, including one prospective way to delegate authorities from the public sector to alternative sectors in the process of public sector reform. Specifically, we show how to match projects of a local government with alternative sectors rationally by using the Analytic Hierarchy Process. The matching process consists of three steps: evaluating projects of a local government; characterizing alternative sectors; and deriving overall judgments. The results of this paper quantitatively clarify the evaluation of projects and the characteristic of sectors, and it is concluded that 35% of local government projects should be devolved from the public sector to alternative sectors.     

AI and computer-based methods in performance evaluation of sporting feats: an overview

Performance evaluation is a complex process, usually involving the analyses of large amounts of possibly subjective information. The complexity increases when the performances of more than one athlete are being evaluated. For example a coach in charge of twenty divers should be able to remember the strengths and weaknesses of each athlete. Given these difficulties, it is therefore not surprising that a number of computer-based systems have been developed to speed-up and improve the quality of performance evaluation. Most of these systems are visually based such that individuals working on performance analysis first record the motion in question by electronic means and then input these images into a computer for quantification and subsequent analysis. There seems to be enormous potential for AI (i.e. Artificial Intelligence) technologies to make a significant contribution in the analysis phase. Indeed AI technologies have been applied to performance evaluation in recent years, though their applicability has been limited for a variety of reasons. The main factor has been a lack of characterisation of the domain of performance evaluation. This paper reviews selected research and applications of computational models and AI technologies in particular in performance evaluation of sporting feats for individual based events.