King Sing Cheung

A petri-net-based synthesis methodology for use-case-driven system design

In use-case-driven system design, one need to derive from a set of use cases an integrated system design that meets at least two objectives. First, the system design must be consistent with the use cases in the sense that the functionalities of the use cases are exactly reflected. Second, the system design must be correct in the sense that the system is free from errors such as deadlock and capacity overflow. The latter is especially important for systems involving some concurrent, sequential, asynchronous, competitive and coordinated processes, such as manufacturing systems. In this paper, we propose a synthesis methodology for use-case-driven system design whereby both objectives are satisfied. In our methodology, use cases are specified as labelled Petri nets, in which the conditions, events and their causal relationships are explicitly represented. A system design is then derived by synthesising these nets into a single consistent whole. Our methodology has two distinctive features, namely, a formal specification of use cases and a rigorous and systematic process for deriving a system design whose correctness and consistency can be optimally achieved. We specifically show its application to manufacturing system design. Promising results are obtained.

A review of e-learning platforms in the age of e-learning 2.0

Online communication is changing the way instructors and learners interact and learn. Today, apart from providing an information repository or a place to search for resources, the new Web 2.0 allows us to find other people, exchange ideas and thoughts, demonstrate creativity and create new knowledge. Based on Web 2.0, e-learning 2.0 has evolved to provide a constructivist learning environment. In this paper, Web 2.0 applications, such as wikis, social bookmarking and podcasts, are reviewed on how they can provide a rich, interactive, user-friendly application platform effectively. The platform would allow teachers and trainers to empower learners and create exciting new learning opportunities. It is more desirable if Web 2.0 technologies can be well integrated into traditional e-learning platforms such as WebCT and blackboard.

A comparison of WebCT, blackboard and moodle for the teaching and learning of continuing education courses

WebCT, Blackboard and MOODLE are three well-known web-based teaming management systems widely used in higher education. This paper compares them functionally, with a special focus on their usage in the teaching and teaming of continuing education courses which are characterised by short duration, few face-to-face contact hours, part-time or distance teaming mode, less coherent student community, less structured but flexible curriculum, flexible study schedules and flexible performance assessment. It is found that all three teaming management systems support curriculum design, communication and discussion, performance assessment and course administration, but at different levels of sophistication. In terms of functionality, WebCT and Blackboard are better than MOODLE, and WebCT is the best. WebCT allows greater flexibility in designing course curriculum and study schedules, which is especially suitable for continuing education courses. With many communication and discussion features, WebCT facilitates active participation among instructors and students of continuing education courses, and allows more varieties in designing teaming materials and resources such as the use of multimedia. The performance assessment and grading functions are also flexible enough to meet the special requirements of a wide spread of continuing education courses.

New characterization for live and reversible augmented marked graphs

erved Augmented marked graphs were first introduced Chu [1]. Based on siphons and mathematical progr ming, Chu found a number of properties of augmen marked graphs pertaining to their liveness and versibility. In recent years, augmented marked gra are often used in manufacturing system design [2 A major reason is that augmented marked graphs h many desirable properties, especially on their liven and reversibility. In this paper, based on some kno properties reported in the literature, we propos new characterization for live and reversible augmen marked graphs. The new characterization provide simpler necessary and sufficient condition for effici checking of their liveness and reversibility, where only a small subset of minimal siphons which can identified through cycles are considered. A manuf turing system example is used for illustration.

Instructional Design Practices for Blended Learning

In recent years, with the advances of the Internet and e-learning technologies, a blended mode of learning, which effectively combines the traditional face-to-face learning and e-learning, has evolved. Yet, this blended learning mode is not widely adopted in higher education. One major reason is that teachers are not familiar with the practices of designing courses under the blended learning environment. This paper investigates the instructional design practices for blended learning. Key steps in the instructional design process are proposed. The whole process begins with writing the course overview and re-designing the lesson plan. Following a blended learning course template, the face-to-face learning elements and e-learning elements are specified. Lesson materials and resources are then developed as learning objects to be launched onto a learning management system. Continuous review is required.

Students’ needs of e-courses as complement to traditional learning: A Japanese studies e-course case

With rapid technological development and strong needs from the students, many institutes have introduced e-learning components to complement traditional face-to-face teaching. This paper investigates the usefulness of different sessions of an alpha Japanese e-learning system based on the survey conducted by the ITS Unit of the HKU SPACE. The learners were asked to test the system and gave feedback in the questionnaire. By examining their likeness to the system and the relative popular sections, features which feed the learnerspsila needs are known. It gives us some insights and direction for future e-learning development. The results of the survey are generally positive and most of the respondents rated the Japanese e-learning system high. It is concluded from the results that learners generally found the Japanese e-learning system helpful to their studies and more specifically, functions like sound emission, flash and videos were relatively helpful in the eyes of learners.

Consistency Analysis on Lifecycle Model and Interaction Model

Two separate models, lifecycle model and interaction model, are generally adopted for specifying object behaviour in object-oriented system development. In this paper, we propose a Petri net-based formal method for analysing consistency between the two models at the logical level. This contributes to improving the consistency in the specification of object behaviour.

Compositional Synthesis of Augmented Marked Graphs

Augmented marked graphs possess some structural characteristics which are desirable for modelling shared-resource systems. This paper investigates the compositional synthesis of augmented marked graphs via a set of common resource places. It is shown that the synthesis preserves boundedness and conservativeness while liveness and reversibility can be preserved under a pretty simple condition. This can be applied to component-based system design, where a system is synthesised from a set of subsystems via common resources. By modelling the subsystems as augmented marked graphs and synthesising them via the corresponding resource places, based on the property-preserving features of this compositional synthesis, the properties of the integrated system can be readily derived.

Student participation index: Student assessment in online courses

Online courses have been widely used to support teaching and learning in higher education. It is essential to develop methods to properly assess students in online course usages. This paper proposes a student participation index for assessing students in online courses. The index consists of a number of components, such as pages viewed and forum questions read and posted, and associated weights. It has the benefits of being non-course-specific, non-subjective, extendible and flexible. The development of the index and how it is used to evaluate students are described in the paper. Results indicate that students with higher index usually achieve better grades and vice versa.

Some Principles for Good Practices of E-learning in Continuing Education Institutions

Electronic learning (e-learning) has become widely adopted in universities and education institutions. This paper summarizes our experience in practicing e-learning in a continuing education institution. Based on our experience, some principles for good e-learning practices are proposed. In brief, e-learning should be more than an e-learning platform. E-learning should be pedagogy driven instead of technology driven. It should be positioned as to complement traditional learning. An e-learning platform need not be developed in-house, and commercialization of an e-learning platform is likely in vain. E-learning should be well integrated with IT support services, and e-course development should be the concerted efforts of both academic and IT staff.