• Asia pacific journal of information systems
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• 제8권3호
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• pp.21-36
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• 1998

Group collaborative systems are recently emerging to support a group of users engaged in common tasks such as group decision making, engineering design, or collaborative writing. Simultaneously, as communications networks and distributed database systems become core underlying architecture of the organization, the need of collaborative systems are gaining more attentions from industry. In such collaborative systems, as the shared objects may evolve constantly or change for operational purposes, providing the users with synchronized and consistent views of the shared object and maintaining the consistency between shared object and replicated objects are important to improve the overall productivity. This paper provides an change management framework for the group collaborative systems to facilitate managing dependency relationships between shared objects and dependents, and coordinating change and propagation activities in distributed computing environments. Specifically, the framework adopts an object-oriented database paradigm and presents several object constructs capturing dependency management and change notification mechanisms. And the proposed framework accommodates both persistent dependents such as replicated data and transient dependents such as various user views in a single formalism. A prototype system is developed on a commercial object-oriented database management system called OBJECTSTORE using the C++ programming language.

• 인터넷정보학회논문지
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• 제11권5호
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• pp.95-104
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• 2010

학습을 이해하는 새로운 패러다임으로 구성주의가 등장하면서 협력학습의 필요성이 강조되고 있다. 특히 교수와 학습에 대한 새로운 접근을 지원하는 테크놀로지로 온라인이 부각되면서 온라인 협력학습에 대한 관심이 증대하고 있다. 본 연구는 온라인 협력학습에서 하나의 주요한 요인인 학습과제 유형에 따른 협력학습 모형을 탐색하여 온라인 협력학습 실제에 도움을 주고자 하였다. 이를 위해 학습과제를 문제해결과제와 지식학습과제로 분류한 후, 학습과제 유형별로 적합한 온라인 협력학습 설계와 환경, 그리고 학습과정을 살펴보았다.

• 인터넷정보학회논문지
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• 제2권5호
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• pp.1-7
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• 2001

본 논문에서는 기업 내 사무업무 프로세스를 자동화하고 보다 효율적인 작업 환경 구축을 위하여 실시간 그룹 협업 지원 기술과 ICN 기반의 워크플로우 모델링 도구를 설계하고 구현한다. 모델링 도구는 그룹 단위의 실시간 협업 지원을 가능하게 하는 워크플로우 비즈니스 프로세스를 정의하므로 "그룹 ICN 에디터"라 부른다. 본 논문에서는 그룹 ICN 에디터가 여러 사용자가 동시에 작업이 가능하게 하기 위해 Flexible rJAMM을 이용하여 에디터를 구현한다. 에디터를 통하여 정의된 워크플로우 비즈니스 프로세스 모델들의 집합은 데이터베이스에 저장이 되고, WfMC에서 표준화한 워크플로우 프로세스 정의 언어(WPDL)로 변환되게 된다.로 변환되게 된다.

• 한국IT서비스학회지
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• 제6권2호
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• pp.113-123
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• 2007

In ubiquitous computing environment such as ubiquitous marketplace (u-market), there is a need of providing context-based personalization service while considering the nomadic user preference and corresponding requirements. To do so, the recommendation systems should deal with the tremendous amount of context data. Hence, the purpose of this paper is to propose a novel recommendation method which provides the products-group list of the customers in u-market based on the shopping intention and preferences. We have developed FREPIRS(FREquent Purchased Item-sets Recommendation Service), which makes recommendation listof product-group, not individual product. Collaborative filtering and apriori algorithm are adopted in FREPIRS to build product-group.

• Advances in aircraft and spacecraft science
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• 제4권3호
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• pp.297-316
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• 2017

With rapid growth in the complexity of large scale engineering systems, the application of multidisciplinary analysis and design optimization (MDO) in the engineering design process has garnered much attention. MDO addresses the challenge of integrating several different disciplines into the design process. Primary challenges of MDO include computational expense and poor scalability. The introduction of a distributed, collaborative computational environment results in better utilization of available computational resources, reducing the time to solution, and enhancing scalability. SORCER, a Java-based network-centric computing platform, enables analyses and design studies in a distributed collaborative computing environment. Two different optimization algorithms widely used in multidisciplinary engineering design-VTDIRECT95 and QNSTOP-are implemented on a SORCER grid. VTDIRECT95, a Fortran 95 implementation of D. R. Jones' algorithm DIRECT, is a highly parallelizable derivative-free deterministic global optimization algorithm. QNSTOP is a parallel quasi-Newton algorithm for stochastic optimization problems. The purpose of integrating VTDIRECT95 and QNSTOP into the SORCER framework is to provide load balancing among computational resources, resulting in a dynamically scalable process. Further, the federated computing paradigm implemented by SORCER manages distributed services in real time, thereby significantly speeding up the design process. Part 1 covers SORCER and the algorithms, Part 2 presents results for aircraft panel design with curvilinear stiffeners.

• Advances in aircraft and spacecraft science
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• 제4권3호
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• pp.317-334
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• 2017

With rapid growth in the complexity of large scale engineering systems, the application of multidisciplinary analysis and design optimization (MDO) in the engineering design process has garnered much attention. MDO addresses the challenge of integrating several different disciplines into the design process. Primary challenges of MDO include computational expense and poor scalability. The introduction of a distributed, collaborative computational environment results in better utilization of available computational resources, reducing the time to solution, and enhancing scalability. SORCER, a Java-based network-centric computing platform, enables analyses and design studies in a distributed collaborative computing environment. Two different optimization algorithms widely used in multidisciplinary engineering design-VTDIRECT95 and QNSTOP-are implemented on a SORCER grid. VTDIRECT95, a Fortran 95 implementation of D. R. Jones' algorithm DIRECT, is a highly parallelizable derivative-free deterministic global optimization algorithm. QNSTOP is a parallel quasi-Newton algorithm for stochastic optimization problems. The purpose of integrating VTDIRECT95 and QNSTOP into the SORCER framework is to provide load balancing among computational resources, resulting in a dynamically scalable process. Further, the federated computing paradigm implemented by SORCER manages distributed services in real time, thereby significantly speeding up the design process. Part 1 covers SORCER and the algorithms, Part 2 presents results for aircraft panel design with curvilinear stiffeners.

• Journal of Information Processing Systems
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• 제17권5호
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• pp.905-917
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• 2021

In recent years, edge computing technology consists of several Internet of Things (IoT) devices with embedded sensors that have improved significantly for monitoring, detection, and management in an environment where big data is commercialized. The main focus of edge computing is data optimization or task offloading due to data and task-intensive application development. However, existing offloading approaches do not consider correlations and associations between data and tasks involving edge computing. The extent of collaborative offloading segmented without considering the interaction between data and task can lead to data loss and delays when moving from edge to edge. This article proposes a range segmentation of dynamic offloading (RSDO) algorithm that isolates the offload range and collaborative edge node around the edge node function to address the offloading issue.The RSDO algorithm groups highly correlated data and tasks according to the cause of the overload and dynamically distributes offloading ranges according to the state of cooperating nodes. The segmentation improves the overall performance of edge nodes, balances edge computing, and solves data loss and average latency.

• 한국통신학회논문지
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• 제27권10C호
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• pp.1015-1026
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• 2002

최근 협력 시스템에 대한 연구가 증가되면서 협력 작업에 대한 연구와 더불어 협력 시스템 보안에 대한 연구가 중요시되고 있다. 협력 시스템에서 인증 및 암호화의 경우 기존의 정책을 사용하여 시스템의 견고성을 유지할 수 있다. 그러나 접근 제어 정책에서 기존의 정책을 그대로 사용하게 되는 경우 분산 환경, 개방된 네트워크, 다양한 주체와 객체의 존재로 인하여 협력 시스템은 신분, 직무, 그룹, 보안등급, 무결성 등급, 허가권을 포함해야 하는 다양한 접근상황을 고려해야 된다. 이 경우, 낮은 보안 등급의 주체가 높은 보안 등급의 객체로 접근을 허용 하거나, 높은 보안 등급의 주체가 낮은 보안 등급의 객체로 접근을 막아야 하는 복합적 상황을 해결하지 못한다. 더욱이 모든 접근상황을 제어하기 위하여 객체에 여러 접근제어 요소를 포함하여 접근 제어를 알고리즘화 할 경우 불필요한 상황을 모두 고려해야 하기 때문에 시스템의 성능 저하를 야기 시킨다. 이 같은 문제를 해결하기 위하여, 본 논문에서는 협력 시스템의 특징에 맞는 새로운 접근제어 프레임워크를 제안한다. 제안된 접근제어의 특징은 주체 및 객체에 다수의 접근 요소를 정의하여 기존 정책 보다 협력시스템과 같은 복합적인 상황에서 용이하게 적용되도록 하였다. 그리고 객체의 종류를 접근될 요소의 특징에 따라 세 가지로 구분하였고, 구분된 각 객체의 특징에 따라 알고리즘이 구현됨으로 빠르고 원활한 협력 작업이 수행되도록 하였다. 또한, 접근 요소 및 정책 변경이 용이하도록 확장성을 고려하였다. 모의실험 결과 다수의 접근 요소를 사용하였지만 시스템 성능은 접근 제어 정책을 적용하지 않았을 때와 큰 차이를 보이지 않았으며 복합적인 상황의 접근제어에서도 확실한 접근 제어가 가능했다.

• Asia pacific journal of information systems
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• 제10권2호
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• pp.51-69
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• 2000

Recently, as business problems become more complicated and require more precise quantitative results, large-scale model management systems are increasingly in demand for supporting the decision-making activities. In addition, as distributed computing over networks gains popularity, departmental computing systems are gradually adopted in an organization to facilitate collaboration of geographically dispersed multiple departments. In departmental collaborative model management systems, multiple departments share common models but approach them with different user-views depending on their departmental needs. Moreover, the shared models become evolved as their structures and the corresponding data sets change due to the dynamic nature of the operating environment and the inherent uncertainty associated with the problems. In such capacity, providing the multiple departmental users with synchronized and consistent views of the models is important to improve the overall productivity. In this paper, we propose a collaborative model management framework for coordinating model change and automatic user-view update in a departmental computing environment. To do so, we describes changes in the model and their effects occurred in departmental model management environments and identifies the constructs and processes for maintaining the consistency between a shared model and its departmental user-views. Especially, in this framework, generic model concept was adopted for accommodating diverse mathematical models in a uniform way in a modelbase and object-oriented database management systems(ODBMS) for combining the model management constructs and automatic user-view update mechanisms in a single formalism. A prototype object-oriented modeling environment was developed using an ODBMS called ObjectStore and $C^{++}$ programming language on Windows NT.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권6호
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• pp.2282-2303
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• 2021

To solve the problems of heavy computing load and system transmission pressure in energy internet (EI), we establish a three-tier cloud-edge integrated EI network based on a cloud-edge collaborative computing to achieve the tradeoff between energy consumption and the system delay. A joint optimization problem for resource allocation and task offloading in the threetier cloud-edge integrated EI network is formulated to minimize the total system cost under the constraints of the task scheduling binary variables of each sensor node, the maximum uplink transmit power of each sensor node, the limited computation capability of the sensor node and the maximum computation resource of each edge server, which is a Mixed Integer Non-linear Programming (MINLP) problem. To solve the problem, we propose a joint task offloading and resource allocation algorithm (JTOARA), which is decomposed into three subproblems including the uplink transmission power allocation sub-problem, the computation resource allocation sub-problem, and the offloading scheme selection subproblem. Then, the power allocation of each sensor node is achieved by bisection search algorithm, which has a fast convergence. While the computation resource allocation is derived by line optimization method and convex optimization theory. Finally, to achieve the optimal task offloading, we propose a cloud-edge collaborative computation offloading schemes based on game theory and prove the existence of Nash Equilibrium. The simulation results demonstrate that our proposed algorithm can improve output performance as comparing with the conventional algorithms, and its performance is close to the that of the enumerative algorithm.