Integration of task networks and cognitive user models using coloured Petri nets and its application to job design for safety and productivity

Changes of task demands due to unforeseen events and technological changes can cause variations in job design such as modifications to job procedures and task allocation. Failure to adapt to job design variations can lead to human errors that may have severe consequences for system safety. Existing techniques for task modelling cannot adequately model how task networks can be adapted to changing work conditions and task demands. Therefore, there is a need to integrate task networks with cognitive user models that indicate how operators process information, make decisions, or cope with suspended tasks and errors. The work described here presents a tool for integrating task and cognitive models using coloured Petri nets. The cognitive user model comprises two modules of attention management (selective and divided attention), a module of memory management of suspended tasks and a module of work organization. Performance Shaping Factors (e.g., workload, fatigue and mental-tracking load) are calculated at any point in time to take into account the context of work (e.g., competing activities, errors and suspended tasks). Different types of human error can be modelled for rule-based behaviours required in proceduralized work environments. Simulation analysis and formal analysis techniques can be applied to process control tasks to verify job procedures, workload management strategies and task allocation schemes in response to technological changes and unfamiliar events.     

An efficient approach to understanding and predicting the effects of multiple task characteristics on performance

Abstract

In ergonomics there is often a need to identify and predict the separate effects of multiple factors on performance. A cost-effective fractional factorial approach to understanding the relationship between task characteristics and task performance is presented. The method has been shown to provide sufficient independent variability to reveal and predict the effects of task characteristics on performance in two domains. The five steps outlined are: selection of performance measure, task characteristic identification, task design for user trials, data collection, regression model development and task characteristic analysis. The approach can be used for furthering knowledge of task performance, theoretical understanding, experimental control and prediction of task performance.

Practitioner Summary: A cost-effective method to identify and predict the separate effects of multiple factors on performance is presented. The five steps allow a better understanding of task factors during the design process.     

The effects of development process modeling and task uncertainty on development quality performance

We examine the impact of development process modeling on outcomes in software development projects, limiting our attention to process and product quality. Modeling the software development process requires a careful determination of tasks and their logical relationships. Essentially, the modeling is undertaken to establish a management framework of the project. We define and interrelate development process modeling, task uncertainty, and development outcomes, as assessed by product and process quality. A survey-based research design was used to collect data to prove our model. The results suggest that development process modeling is positively related to both product and process quality, while task uncertainty is negatively related to them. Development process modeling reduces the negative impact of task uncertainty on quality-oriented development outcomes. Development projects operating with high levels of task uncertainty should consider defining development process models that provide a framework for management of the project by establishing tasks and their logical interrelationships. Such a model should promote shared understanding of the work process among development constituents and enhance resource utilization efficiency.     

基于软件总线的星载系统软件结构的研究与设计

针对目前国内外星载系统软件可重构性较差的问题,提出了一种基于软件总线的星载系统软件结构。首先，介绍了软件总线和软构件的结构。其次，阐述了星载实时多任务操作系统中混合任务调度算法的设计。最后，对这个混合任务调度算法的正确性给出了证明。     

The development of a model and simulation of an aviation maintenance technician task performance

This paper describes the model of an aircraft maintenance technician (AMT) behaviour working in a real world environment and the application of this model in a computer simulation. The model was derived from the combination of two existing models of cognition (SHELL and RMC/PIPE), based on the paradigm of an information processing system. The simulation structure was developed by transforming the model into an action-execution structure and implementing this model in a computer program based on an object-oriented programming language. An error generation system was coupled to a simple taxonomy of causal correlations between socio-technical and contextual factors operating in an environment defined by a comprehensive task analysis. The simulator can be applied to many aviation maintenance tasks to assist in the design of aviation maintenance training systems through the analysis of the interaction of performance influencing factors and possible AMT performances during the execution of normal maintenance operations. A number of sample outputs from the simulator show the potential of the results to assist in training development. A discussion is also made of other potential applications and the future directions the simulator structure can take.     

A strategy for improving worker satisfaction and job attitudes in a repetitive industrial task: application of production standards and performance feedback

Worker satisfaction improved significantly as a consequence of the provision of the assigned and participative standards with performance feedback in a repetitive industrial production task. The maximum improvement in worker satisfaction was found for the participative standard and feedback condition. Only this condition had a significant positive effect on worker job attitudes. Monetary incentive, when provided with an assigned or participative standard with feedback, added no incremental worker satisfaction or job attitudes gain. The participative standard with feedback condition emerges as the optimum strategy for improving worker satisfaction and job attitudes in a repetitive industrial production task.     

The effects of topology and task complexity on digital‐speech‐desktop interface design and evaluation

Abstract— This study investigated user task performance in terms of three interface proposals (linear, hierarchical, and network type) and task complexities (single‐layered, double‐layered, and triple‐layered). Forty‐two participants (all male), aged 19–23 years, were recruited for the experiment. The results generated from this study reveal that the different degrees of task complexity interacted with the topological structures of the user interfaces. No difference was found among the three topological structures in the single‐layered task. A linear structure resulted in better user performance than network or hierarchical structures in the double‐layered task, while in the triple‐layered task both network and hierarchical structures resulted in better user performance than a linear topological structure. This study provides an example of the application of topological structures in interface design and evaluation. From a practical perspective, the results imply the necessity of alternative or parallel control systems (linear and hybrid topologies) so that the user can shift between structures according to task complexity.     

The effect of information availability in a user interface (UI) on in-vehicle task performance: A pilot study

When performing an in-vehicle operation, the information display is a crucial element that decides the operator's control behaviors. The interaction between information presentation and operator's in-vehicle task performance is critical for vehicle safety. The question arises: What is the optimum availability of information? The aim of this study is to investigate the relationships between different information availabilities and operation performances as operators interact with an in-vehicle user interface (UI) to complete a simulated train driving task. The results show that some types of information significantly affect the operator's task performance. Information that improved the task performances were closely associated with specific task requirements. The participants' task performance indicated that they had a better awareness of a task situation and were better at controlling their virtual vehicle when completing time and process-restricted tasks with limited, relevant information. These results support the conclusion that more information does not always promote accuracy and safety during the task completion.Relevance to industryThis study presents a unique insight into the information display of in-vehicle UI design for vehicle control. The information available within an in-vehicle interface should be optimized by performance assessments to provide more useful information; this has significant positive effect on operator performance from an accuracy and safety perspective. Thus, this study provides advice for designing an in-vehicle UI.     

Impact of information technology on users' work environment: A case of computer aided design (CAD) system implementation

Study of the possible impacts of a new information system or technology on its users is an important area of MIS research. Understanding and identifying favorable and unfavorable impacts of implementation on users should be helpful in developing better design guidelines and choices to take full advantage of the potential of information technology, while minimizing the possible negative consequences for users. This paper presents the details of impacts created by the implementation of a computer aided design (CAD) system for part designers at an automotive parts manufacturer. The paper employs equity–implementation (E–I) model as a framework to help identify and analyze the impacts of CAD technology implementation on part designers' work environment. The paper identifies changes in the designers' inputs and outcomes as a result of CAD implementation. On the whole the impacts were found to be favorable for designers, the manufacturing organization, and its customers. The paper concludes that the E–I model provides a useful framework to help assess the nature of impacts created by the new system. The reactions of designers to the new system were also found to be consistent with the E–I model.     

Analysis and design of a real-time manufacturing subsystem

The purpose of this paper is to present a system methodological approach to designing a computer based manufacturing subsystem. The subsystem, a manual job costing system, is explained and a summary of design procedures for converting this manual system to a computer based information system is provided.     

From generative fit to generative capacity: exploring an emerging dimension of information systems design and task performance

Information systems (IS) research has been long concerned with improving task-related performance. The concept of fit is often used to explain how system design can improve performance and overall value. So far, the literature has focused mainly on performance evaluation criteria that are based on measures of task efficiency, accuracy, or productivity. However, nowadays, productivity gain is no longer the single evaluation criterion. In many instances, computer systems are expected to enhance our creativity, reveal opportunities and open new vistas of uncharted frontiers.
To address this void, we introduce the concept of generativity in the context of IS design and develop two corresponding design considerations –'generative capacity' that refers to one's ability to produce something ingenious or at least new in a particular context, and 'generative fit' that refers to the extent to which an IT artefact is conducive to evoking and enhancing that generative capacity. We offer an extended view of the concept of fit and realign the prevailing approaches to human–computer interaction design with current leading-edge applications and users' expectations. Our findings guide systems designers who aim to enhance creative work, unstructured syntheses, serendipitous discoveries, and any other form of computer-aided tasks that involve unexplored outcomes or aim to enhance our ability to go boldly where no one has gone before.
In this paper, we explore the underpinnings of 'generative capacity' and argue that it should be included in the evaluation of task-related performance. Then, we briefly explore the role of fit in IS research, position 'generative fit' in that context, explain its role and impact on performance, and provide key design considerations that enhance generative fit. Finally, we demonstrate our thesis with an illustrative vignette of good generative fit, and conclude with ideas for further research.     

Contextualising design: Aspects of using usability context analysis and hierarchical task analysis for software design

Usability Context Analysis is part of ISO 9241-11 and, as such, is recommended for use in user-centred design. However, studies involving a critical assessment of usability context analysis within the software domain are scarce; this paper details two small studies that involved the use of usability context analysis (UCA) and hierarchical task analysis (HTA). The first system involved designing a small subsite of a larger website, while the second system was a small database designed as part of an exercise by UK university students. Post-design evaluation suggested that the use of both UCA and HTA, rather than one or the other, was beneficial in gathering and analysing user requirements.     

Contextualising design: Aspects of using usability context analysis and hierarchical task analysis for software design

Usability Context Analysis is part of ISO 9241-11 and, as such, is recommended for use in user-centred design. However, studies involving a critical assessment of usability context analysis within the software domain are scarce; this paper details two small studies that involved the use of usability context analysis (UCA) and hierarchical task analysis (HTA). The first system involved designing a small subsite of a larger website, while the second system was a small database designed as part of an exercise by UK university students. Post-design evaluation suggested that the use of both UCA and HTA, rather than one or the other, was beneficial in gathering and analysing user requirements.     

A computer aided design method for car form and its application based on shape parameters

In the early design stage, automotive modeling should both meet the requirements of aesthetics and engineering. Therefore, a vehicle CAD (computer aided design) model that can be easily adjusted by feedbacks is necessary. Based on CE-Bézier surface, this paper presents a set of algorithms for parametric segmentation and fairing surface generation in a car model. This model is defined by a simplified automotive template and relevant control points, shape parameters and segmentation parameters, which can be modified to alter the car form efficiently. With this model and the corresponding adjustment method, more than fifty various vehicle models are established in this research according to different parameters. And two methods for calculating similarity index between car models are constructed, which are suitable for brand design trend analysis and modelling design decisionmaking.     

The implications of cross-regional differences for the design of In-vehicle Information Systems: a comparison of Australian and Chinese drivers

The increasing global distribution of automobiles necessitates that the design of In-vehicle Information Systems (IVIS) is appropriate for the regions to which they are being exported. Differences between regions such as culture, environment and traffic context can influence the needs, usability and acceptance of IVIS. This paper describes two studies aimed at identifying regional differences in IVIS design needs and preferences across drivers from Australia and China to determine the impact of any differences on IVIS design. Using a questionnaire and interaction clinics, the influence of cultural values and driving patterns on drivers' preferences for, and comprehension of, surface- and interaction-level aspects of IVIS interfaces was explored. Similarities and differences were found between the two regional groups in terms of preferences for IVIS input control types and labels and in the comprehension of IVIS functions. Specifically, Chinese drivers preferred symbols and Chinese characters over English words and were less successful (compared to Australians) at comprehending English abbreviations, particularly for complex IVIS functions. Implications in terms of the current trend to introduce Western-styled interfaces into other regions with little or no adaptation are discussed.     

Software performance tuning of software product family architectures: Two case studies in the real-time embedded systems domain

Software performance is an important non-functional quality attribute and software performance evaluation is an essential activity in the software development process. Especially in embedded real-time systems, software design and evaluation are driven by the needs to optimize the limited resources, to respect time deadlines and, at the same time, to produce the best experience for end-users. Software product family architectures add additional requirements to the evaluation process. In this case, the evaluation includes the analysis of the optimizations and tradeoffs for the whole products in the family. Performance evaluation of software product family architectures requires knowledge and a clear understanding of different domains: software architecture assessments, software performance and software product family architecture. We have used a scenario-driven approach to evaluate performance and dynamic memory management efficiency in one Nokia software product family architecture. In this paper we present two case studies. Furthermore, we discuss the implications and tradeoffs of software performance against evolvability and maintenability in software product family architectures.     

基于聚类方法的软件设计与应用

通过对聚类算法和技术的研究,设计和研制了层系优化配套软件,并应用到油田的开发层系细分与优化.通过分析东辛地区沙河街组的沙二段8-11砂层组8个小层的实体属性,用研制的细分开发层系软件对辛16断块的层系进行划分与组合评价,最终优选出合理的开发层系组合,表明了聚类方法技术在油藏高含水期细分开发层系中的可行性和科学性.     

Effects of GSS interface and task type on group interaction: An empirical study

The effects of GSS interface and task type on group interaction are examined in this experimental study. A 2 × 2 factorial design is employed. Each treatment has eight groups. Two types of GSS interfaces are studied: icon-based and text-based. Two task types are investigated: intellective and preference. Three dependent variables are measured: efficiency of influence attempts, inequality of influence attempts, and dominance significance. Results of data analysis show that groups using icon-based interface achieve greater efficiency of influence attempts, greater equality of influence attempts, and less dominance significance than groups using text-based interface. Moreover, equality of influence attempts is greater for preference task groups than intellective task groups. These results suggest that an icon-based interface is a useful feature of a GSS, particularly when group members are novice computer users. GSS developers should, therefore, pay attention to interface design on top of the considerations for other GSS features.     

基于检查点和Rejuvenation的软件运行模型分析

近来的研究表明,长时间运行的通信软件往往存在老化现象。为防止软件老化引起的突发性系统停机,提高系统的可靠性,人们提出了一种预防性的软件容错策略,称为rejuvenation。由于它的过程复杂,总的停机成本仍然是可观的。检查点是一种轻量级的软件容错策略,其成本远小于rejuvenation的成本。该文通过合理结合rejuvenation和检查点技术,实现了降低总的系统停机成本的目的。文中给出了系统的Petri网模型,并结合实例进行了分析。