• Journal of KIISE:Software and Applications
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• v.28 no.3
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• pp.249-261
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• 2001

웹 기반의 워크플로우 시스템은 기업간 전자상거래에 필수적인 요소로 부각되고 있다. 그러나 상이한 벤더들에 의해 제작된 워크플로우 엔진들은 상호운영성이 보장되지 않기 때문에 전자상거래의 제기능을 발휘하지 못한다. 이와 같은 문제를 해결하기 위한 노력으로 WfMC(Workflow Management Coalition)에서는 워크플로우 시스템간의 상호운영성을 위한 기본 명세를 제공하고 있으나, 인터넷상에서의 구체적인 활용방안은 제시되지 못하고 있다. 본 논문에서는 워크플로우 시스템 사이의 데이타 교환을 위한 프레임워크(WDEF : Workflow Data Exchange Framwork)를 제시한다. WDEF는 데이타 레지스트리를 중심으로 하여 워크플로우간 상호운영성을 제공하기 위한 메타데이타를 기술하고, 네트워크 상의 자원을 기술하기 위한 기반 기술인 RDF(Resource Description Framework)를 이용하여 워크플로우간의 메시지를 구성한다. 데이타 레지스트리를 이용함으로써, WDEF는 WfMC에서 정의하는 워크플로우 상호운영성을 위한 요구조건들을 모두 수용하면서 보다 확장성 있고 유연한 구조를 가지며, RDF에 기반한 자동적인 XML 인코딩을 통해 전자 상거래에 이용되는 다른 XML문서와도 완벽한 호환성을 가진다.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.197-208
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• 2003

Abstract Workflow is not appropriately applied to coordinated execution of applications(steps) that comprise business process such as a collaborative series of tasks because of the lacks of network infra, standard of information exchange and data consistency management with conflict mode of shared data. Particularly we have not mentioned the problem which can be occurred by shared data with conflict mode. In this paper, to handle data consistency in the process of rollback for failure handling or recovery policy, we have classified rollback dependency into three types such as implicit rollback dependency in a transactional workflow, implicit rollback dependency in collaborative transactional workflows and explicit rollback dependency in collaborative transactional workflows. Also, we have proposed the rollback dependency compiler that determines above three types of rollback dependency. A workflow designer specifies the workflow schema and the resources accessed by the steps from a global database of resources. The rollback dependency compiler generates the enhanced workflow schema with the rollback dependency specification. The run-time system interprets this specification and executes the rollback policy with data consistency if failure of steps is occurred. After all, this paper can offer better correctness and performance than state-of-the-art WFMSs.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.232-242
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• 2005

This paper concerns automatic hardware synthesis from data flow graph (DFG) specification for fast HW/SW cosynthesis. A node in BFG represents a coarse grain block such as FIR and DCT and a port in a block may consume multiple data samples per invocation, which distinguishes our approach from behavioral synthesis and complicates the problem. In the presented design methodology, a dataflow graph with specified algorithm can be mapped to various hardware structures according to the resource allocation and schedule information. This simplifies the management of the area/performance tradeoff in hardware design and widens the design space of hardware implementation of a dataflow graph compared with the previous approaches. Through experiments with some examples, the usefulness of the proposed technique is demonstrated.

• Journal of KIISE:Databases
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• v.27 no.4
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• pp.613-626
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• 2000

전통적인 워크플로우 패러다임에 있어서는 하나의 워크플로우가 자동으로 실행되기 위해서는 사전에 해당 워크플로우 탬플릿이 정의되어야 한다. 하지만 많은 경우에 있어서 프로세스 생성시에 전체 워크플로우를 명확하게 정의 할 수 없는 상황이 발생한다. 그러한 경우에는 워크플로우 파편을 통합하여 유도되는 것이 적절하다. 워크플로우 관리시스템이 그러한 상황에 대처하기 위해서는 실행 중에 워크플로우를 정의하는 기능을 갖출 필요가 있다. 본 논문에서는 워크플로우 관리시스템에서 실행 중 워크플로우 정의 기능을 어떻게 수용할 것인지에 관해서 소개하고 그러한 기능을 수용하는 워크플로우 관리 시스템이 어떠한 구조이어야 하는지에 관해서 논의한다. 본 논문에서는 또한 실행 중 워크플로우 정의를 위한 세가지 워크플로우 파편 템플릿이 소개되며 이것들로부터 전체 워크플로우를 유도하는 알고리즘이 고안되었다. 실행 중 워크플로우 정의 기능을 구현하기 위해서는 커넥터 메커니즘이 고안되었으며 이것의 구조와 기능도 소개된다.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.9_10
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• pp.429-440
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• 2008

As embedded system becomes more complex, software development becomes more important in the entire design process. Most embedded applications consist of multi -tasks, that are executed in parallel. So, dataflow model that expresses concurrency naturally is preferred than sequential programming language to develop multitask software. For the execution of multitasking codes, operating system is essential to schedule multi-tasks and to deal with the communication between tasks. But, it is needed to execute multitasking code without as when the target hardware platform cannot execute as or target platforms are candidates of design space exploration, because it is very costly to port as for all candidate platforms of DSE. For this reason, we propose the serialized multitasking code generation technique from dataflow specification. In the proposed technique, a task is specified with dataflow model, and generated as a C code. Code generation consists of two steps: First, a block in a task is generated as a separate function. Second, generated functions are scheduled by a multitasking scheduler that is also generated automatically. To make it easy to write customized scheduler manually, the data structure and information of each task are defined. With the preliminary experiment of DivX player, it is confirmed that the generated code from the proposed framework is efficiently and correctly executed on the target system.

• Journal of KIISE:Databases
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• v.27 no.4
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• pp.604-612
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• 2000

시간 제약을 가지는 워트플로우에서 만약 워크플로우 인스턴스가 마감 시간 안에 종료되지 못하면, 워크플로우 관리 시스템은 보상 처리와 같은 예외적인 조치들을 취할 것이다. 이러 한 상황은 시스템에게 과부하를 주기 때문에 워크플로우 처리의 성능을 저하시킨다. 이에 본 논문에서는 고성능 워크플로우 인스턴스들의 수를 증가시킬 수 있는 새로운 기법을 제안 한다. 그리고 임계경로에 속하는 각 임계 액티비티의 처리 용량을 향상시키기 위해 최소 중 복 서버의 개수를 결정하는 방법을 제안한다. 마지막으로, 실험들을 통하여 본 논문에서 제 안된 기법의 유용함을 보인다.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.310-319
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• 2003

Workflow is defined as the automation of a business process, and consists of interrelated workflow tasks. Because many modem business processes nay involve activities that are geographically distributed between different departments or organizations, workflow inherently has the characteristics of distribution. In distributed workflow systems, each workflow task performs its assigned role by utilizing information resources placed at some hosts, and then transmits workflow execution control to the next tasks in a workflow definition. Hence, it is very important to appropriately allocate workflow tasks to hosts for high performance workflow processing. In this paper, we propose a multilevel workflow graph partitioning scheme for efficient placement of workflow tasks. This method can improve the performance of workflow processing by minimizing the remote communication costs occurred during workflow execution.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.395-405
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• 2001

In this paper, we analyze workflow management system in programming language aspects. Many workflow characteristics such as workflow relevant data, workflow control structures, and workflow application invocations are studied and compared with those of distributed parallel programs. Although there exist minor differences between them, we found that there exist surprisingly many analogies between them. Based on this observation, we suggest to view workflow management system as distributed parallel program development platform. This new view on workflow management system provides users consistent view on workflow and workflow management system and with this view workflow management system designer can cope with arbitrary requests from the users keeping design consistency. Moreover the analogy between workflow and program provides a basis to apply program analysis techniques to the analysis of workflow.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.677-687
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• 2001

The critical path has been widely applied to many areas of computer engineering especially a directed acyclic graph. Its concept can also be useful in the context of a workflow. The workflow critical path is defined as a path which has the longest average execution time from the start activity to the end activity of workflow. Because there can be several concurrently executed workflow instances for a specific workflow a new method to determine the critical path should be developed. In this paper we specify our workflow queuing network model from which we can easily analyze many workflow characteristics. Based on this workflow model. we propose a method to identify the critical path In addition, we show come workflow areas which can utilze the critical path.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.5
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• pp.375-384
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• 2004

The Grid is new infrastructure to provide computing environment for grand challenge research by sharing large-scale resources. Currently the Globus becomes a de facto standard middleware to construct Grid and supports core services such as resource management, security, data transfer, information services, and so on. However, it still needs more works and researches to satisfy requirements from various grid applications. A workflow management is becoming a main service as one of the important grid services for complex grid applications. We propose a Meta Scheduling Framework (MSF) in this paper. The MSF provides a XML-based Job Control Markup Language (JCML) for describing information and procedures of grid applications, and a workflow management service for scheduling the job using the JCML and for processing the job effectively.