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The conventional approach to developing expert systems views the domain of application as being formally defined. This view often leads to practical problems when expert systems are built using this approach. This paper examines the implications and problems of the formal approach to expert system design and proposes an alternative approach based on the concept of semi-formal domains. This approach, which draws on the work of socio-technical information systems, provides guidelines which can be used for the design of successful expert systems.  相似文献   

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Many efforts in the area of computer security have been drawn to attribute-based access control (ABAC). Compared to other adopted models, ABAC provides more granularity, scalability, and flexibility. This makes it a valuable access control system candidate for securing platforms and environments used for coordination and cooperation among organizations and communities, especially over open networks such as the Internet. On the other hand, the basic ABAC model lacks provisions for context, trust and privacy issues, all of which are becoming increasingly critical, particularly in high performance distributed collaboration environments. This paper presents an extended access control model based on attributes associated with objects and subjects. It incorporates trust and privacy issues in order to make access control decisions sensitive to the cross-organizational collaboration context. Several aspects of the proposed model are implemented and illustrated by a case study that shows realistic ABAC policies in the domain of distributed multiple organizations crisis management systems. Furthermore, the paper shows a collaborative graphical tool that enables the actors in the emergency management system to make better decisions. The prototype shows how it guarantees the privacy of object’s attributes, taking into account the trust of the subjects. This tool incorporates a decision engine that relies on attribute based policies and dynamic trust and privacy evaluation. The resulting platform demonstrates the integration of the ABAC model, the evolving context, and the attributes of actors and resources.  相似文献   

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Most of the projects which envision knowledge dissemination create and use a unique knowledge base, where all items acquired are organized according to a simple classification. This kind of ‘centralized’ approach shows some inconsistencies in relation to many of the theories about the creation of knowledge and its dissemination. Due to them, distribution and sociability are essential characteristics for the creation and sharing of knowledge. This incoherence partially explains the reason which leads many users into abandoning this kind of system because they have to adapt themselves to a classification and a rigid structure to represent pieces of knowledge. On the other hand, a lot of tacit knowledge and interaction possibilities are lost in this centralized vision. So, based on the advantages of a distributed approach for knowledge dissemination and the improvement of interaction, we designed and constructed the Mobile Exchange of Knowledge (MEK). This approach involves, in a mobile way, the exchanging of knowledge among people who share the same interests. Some issues like ad-hoc networks, social networks, location prediction and distributed knowledge management are also related to the MEK concept. However, to verify how effective our idea is, we conducted an experiment in the geographical space of a university in Brazil where we analyzed the movements of students and also their interest and willingness to share knowledge items.  相似文献   

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Maturity is defined as a measure to evaluate the capabilities of an organization in regards to a certain discipline. The Collaborative Planning Process is a very complex process and Coordination mechanisms are especially relevant in this field to align the plans of the supply chain members. The objective of this paper is to develop a maturity model and a methodology to perform assessment for the Structural Elements of Coordination Mechanisms in the Collaborative Planning Process. Structural elements are specified in order to characterize coordination mechanisms in a collaborative planning context and they have been defined as key areas to be assessed by the maturity model. The identified structural elements are: number of decision-makers, collaboration level, interdependence relationships nature, interdependence relationships type, number of coordination mechanisms, information exchanged, information processing, decision sequence characteristics and stopping criteria. Structural elements are assessed using the scheme of five levels: Initial, Repeatable, Defined, Managed and Optimized. This proposal has been applied to a ceramic tile company and the results are also reported.  相似文献   

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Collaborative learning is perceived as an important component of Information Communication Technologies (ICT) integration in schools. The purpose of this study was to examine an initiative of the Ministry of Education that promoted intra-school and inter-school digital collaborative learning projects. The participants were 159 district ICT leaders, who designed 37 digital collaborative projects containing 73 learning activities to promote inter-school student interactions. The study was conducted within the qualitative research paradigm through analysis of digital collaborative learning activities. Additionally, the participants were required to share their experiences regarding digital collaboration through an open-ended online questionnaire. The thematic analysis revealed all four levels of the SAMR model, rating pedagogical changes during technological integration; the most common were the model's two middle levels: Augmentation and Modification. Moreover, we explored the degree of teamwork (information sharing, cooperation, or collaboration), complexity of collaboration (intra-school vs. inter-school) and sustainability of collaborative learning within the school culture. Most of the activities reflected the cooperation level of teamwork, while in the highest level—collaboration was less common. Surprisingly, complexity of collaboration and its sustainability in school culture were negatively interconnected. Regarding the extent of collaboration, some activities were categorized as “Islands of innovation,” the majority were comprehensive and conducted on the organizational level, while only few involved the wider community-parents or other stakeholders. Based on the bottom-up analysis of pedagogical changes in digital collaboration activities, we suggested a comprehensive e-CSAMR framework. The implications for educational theory and practice are discussed.  相似文献   

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This paper addresses the problem of dynamics analysis in optical networks from a system control perspective. A general framework for finding the transfer matrix representation of an optical network is developed, based on linear fractional transformations. Under the natural assumption of equal time-delay for all channels in a link, the network transfer matrix is simplified such that channel cross-coupling is evidenced. The optical network stability problem is then reformulated as a robust stability problem and stability conditions are developed by applying μ-analysis.  相似文献   

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In this paper, a self-recurrent wavelet neural network (SRWNN)-based indirect adaptive control architecture is modified for performing speed control of a motion platform. The transient behaviour of the original learning algorithm has been improved by modifying the learning rate updates. The contribution of the proposed modification has been verified via both simulations and experiments. Moreover, the performance of the proposed architecture is compared with robust RST designs performed on a similar benchmark system, to show that via adaptive nonlinear control, it is possible to obtain a fast step response without degrading the robustness of a multi-body mechanical system. Finally, the architecture is further improved so as to possess structural learning for populating the SRWNNs automatically, rather than employing static network structures, and simulation results are provided to show the performance of the proposed structural learning algorithm.  相似文献   

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Abstract. The term 'complex informated domain' refers to a work environment characterized by high complexity and onerous cognitive demands, in which the management of a remote process is mediated by an information system (IS). Such work environments are typical of highly technical domains, such as industrial process control, but as computer-based information systems penetrate ever deeper into modern businesses, all organizations are taking on the same 'informated' characteristics. This paper reports an experiment using a rich simulation ('a microworld'), which attempted to throw light on human–machine dynamics in such complex environments. Two issues were investigated: the state of the subject (fatigue induced by sleep loss) and the degree of operator control (empowerment) afforded by the IS interface. Results showed that sleep deprivation led to no degradation in overt performance but, contrary to expectations, lower performance was associated with high control operation. A detailed qualitative analysis showed the high control interface to encourage a more proactive control style, whereas fatigue intensified primitive, reactive strategies. The findings emphasize that cognition is a goal-directed, adaptive system not simply an information-processing mechanism. A model of cognitive dynamics is outlined that distinguishes a hierarchy of control levels: anxiety defences, reactive control and strategic control. In general, the experiment shows the potential value to IS research of the microworld paradigm as a tool for developing theory and exploring key design issues.  相似文献   

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The Land Transformation Model (LTM), which couples geographic information systems (GIS) with artificial neural networks (ANNs) to forecast land use changes, is presented here. A variety of social, political, and environmental factors contribute to the model's predictor variables of land use change. This paper presents a version of the LTM parameterized for Michigan's Grand Traverse Bay Watershed and explores how factors such as roads, highways, residential streets, rivers, Great Lakes coastlines, recreational facilities, inland lakes, agricultural density, and quality of views can influence urbanization patterns in this coastal watershed. ANNs are used to learn the patterns of development in the region and test the predictive capacity of the model, while GIS is used to develop the spatial, predictor drivers and perform spatial analysis on the results. The predictive ability of the model improved at larger scales when assessed using a moving scalable window metric. Finally, the individual contribution of each predictor variable was examined and shown to vary across spatial scales. At the smallest scales, quality views were the strongest predictor variable. We interpreted the multi-scale influences of land use change, illustrating the relative influences of site (e.g. quality of views, residential streets) and situation (e.g. highways and county roads) variables at different scales.  相似文献   

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We apply activity theory (AT) to design adaptive e-learning systems (AeLS). AT is a framework to study human’s behavior at learning; whereas, AeLS enhance students’ apprenticeship by the personalization of teaching–learning experiences. AeLS depict users’ traits and predicts learning outcomes. The approach was successfully tested: Experimental group took lectures chosen by the anticipation AT principle; whilst, control group received randomly selected lectures. Learning achieved by experimental group reveals a correlation quite significant and high positive; but, for control group the correlation it is not significant and medium positive. We conclude: AT is a useful framework to design AeLS and provide student-centered education.  相似文献   

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