• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.605-619
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• 2010

Caching of frequently accessed data in multi-hop ad hoc environment is a technique that can improve data access performance and availability. Cooperative caching, which allows sharing and coordination of cached data among several clients, can further en-hance the potential of caching techniques. In this paper, we propose a fuzzy cooperative caching scheme in mobile ad hoc networks. The cache management of the proposed caching scheme not only uses adaptively CacheData or CachePath based on data sim-ilarity and data utility, but also uses the replacement manager based on data pro t. Also, the proposed caching scheme uses a prefetch manager. When the TTL of the cached data expires, the prefetch manager evaluates the popularity index of the data. If the popularity index is larger than a threshold, the data is prefetched. Otherwise, its space is released. The performance of the proposed scheme is evaluated analytically and is compared to that of other cooperative caching schemes.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.522-534
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• 2017

According to the characteristics of salvo attack for the multiple flight vehicles (MFV), the design of cooperative guidance law can be converted into the consensus problem of multi-vehicle system through the concept of multi-agent cooperative control. The flight vehicles can be divided into leader and followers depending on different functions, and the flight conditions of leader are independent of the ones of followers. The consensus problem of leader-follower multi-vehicle system is researched by graph theory, and the consensus protocol is also presented. Meanwhile, the finite time guidance law is designed for the flight vehicles via the finite time control method, and the system stability is also analyzed. Whereby, the guidance law can guarantee the line of sight (LOS) angular rates converge to zero in finite time, and hence the cooperative attack of the MFV can be realized. The effectiveness of the designed cooperative guidance method is validated through the simulation with a stationary target and a moving target, respectively.

• Journal of the Korean Society of School Health
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• v.35 no.3
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• pp.113-122
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• 2022

Purpose: The purpose of this study was to identify the effects of applying jigsaw cooperative learning to basic nursing practicums on self-directed learning ability, self-efficacy, and learning outcomes. Methods: This study was based on a non-equivalent control group design, and the subjects were nursing students. The study allocated 30 people in the experimental group and 30 people in the control group, and jigsaw cooperative learning was applied to the experimental group for 2 hours every week for a total of 8 weeks. The traditional educational method was applied to the control group. The collected data were analyzed using SPSS v26.0. Results: The experimental group to which jigsaw cooperative learning was applied showed statistically significant differences in self-directed learning ability (F=4.49, p=.038), self-efficacy (F=6.15, p=.016), and learning outcomes (F=19.48, p<.001) compared to the control group. Conclusion: By applying jigsaw cooperative learning to basic nursing practicums, this study confirmed its effect not only on the effective domain such as self-directed learning ability and self-efficacy, but also on learning outcomes in the practical domain. We propose future studies apply jigsaw cooperative learning to various practice classes to achieve learning outcomes that focus on cultivating students' practical capabilities.

• Korean Journal of Computational Design and Engineering
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• v.13 no.6
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• pp.412-420
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• 2008

In order to design the large complex structures like VLFS (Very Large Floating Structures), it is essential the cooperation between the experts in various fields; structural engineering expert, fluid mechanics expert, mooring system engineer, and so on. This paper describes the development of an integrated system to support the cooperative design between various experts and project manager. This integrated system is designed to be operated in Web environment and it contains the support of design DB and 3D graphical tool, negotiation tool for task allocation, and various engineering supporting tools for each design step. The user group of this system can be classified as Project Manager, Engineering Expert, DB Builder, and System Administrator. All of the engineering data is saved after and during the process of the design projects and all participants can be connected by Internet without the limit of time or space constraints.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.06a
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• pp.83-88
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• 1997

In this study, we focus on precise and natural cooperative object manipulation in a virtual space. We introduce two virtually expanded physical laws-virtual mechanical equilibrium on a rigid object and exclusive object arrangement-to create realistic cooperative manipulation. We have built a trial system according to our proposed design. The method is expected to allow users to exchange intended manipulation by haptic and visual channels.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.137-148
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• 2011

Different from the traditional client-server model, it is possible for participants in a cooperative distributed system to get quality services regardless of the number of participants in the system since they voluntarily pool or share their resources in order to achieve their common goal. However, some selfish participants try to avoid providing their resources while still enjoying the benefits offered by the system, which is termed free-riding. The results of free-riding in cooperative distributed systems lead to system collapse because the system capacity (per participant) decreases as the number of free-riders increases, widely known as the tragedy of commons. As a consequence, designing an efficient incentive mechanism to prevent free-riding is mandatory for a successful cooperative distributed system. Because of the importance of incentive mechanisms in cooperative distributed system, a myriad of incentives mechanisms have been proposed without a standard for performance evaluation. This paper draws general incentive design considerations which can be used as performance metrics through an extensive survey on this literature, providing future researchers with guidelines for the effective incentive design in cooperative distributed systems.

• Journal of the Korean Society of Costume
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• v.58 no.6
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• pp.110-123
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• 2008

The objectives of this study are to define the fundamental notions of collaboration in design field. The results of this study are summarized as follows: Firstly, collaboration means a cooperative work which are cooperatively done by collabarator and collaboratee on the equal status within a certain period of time, based on core ability of each of them. This cooperative work is presented with a visual image based on the identity of participants, and it creates an added value. Collaboration is different from convergence and hybrid in the methodological aspects and from brand alliance and strategic alliance in the aspects of the subject of project. Secondly, collaboration has been developing through step of using the specific ability, step of sharing each core abilities, and step of fusing their identities, in a view of the sphere of cooperative work and the intimate relations in reciprocity. Thirdly, according to strategic purpose, collaboration can be classified into value ascending collaboration, image changing collaboration, business-field extension collaboration, and event collaboration. Fourthly, production methods of collaboration consist of limited edition method, premium line method, common line method, producing a collaborative product, and so on. Fifthly, differentiation effect, image upgrade effect, production of higher value-added products, sale increase, diversification of business, sharing the targets, and promotion effect are achievable through collaboration. Sixthly, to make progress in collaboration successfully, the compatibility of combination between collaborator and collaboratee, the superiority of collaboratee, definitude of collaboration, the fit method of collaboration, the novelty of collatoration, possibility of issuing of collaboration, and perfection of collabo-product must be the points which deserve our attention.

• Journal of Engineering Education Research
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• v.13 no.2
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• pp.33-37
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• 2010

This paper deals with the introduction of capstone design project by team activities in Department of Electronics and Communication Engineering, Korea Maritime University. This course is referred to as Creative Engineering Design for spring semester of 4th-year undergraduates. The course focuses on creative thinking and cooperative mind to students by learning engineering design skills, realizing their idea through design project and recognizing practicality of their systems. The intent of the course is to provide a true "capstone" experience, where students can combine their skills to achieve the successful completion of a project. This paper describes class process and evaluation method, and cooperative works with mentees and industrial mentors connected through Hanium network for IT mentoring activities.

• Architectural research
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• v.13 no.3
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• pp.31-40
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• 2011

Profit-keeping behaviors naturally occur in the market to satisfy consumers, and the logic behind it lies in the economies of scale. On the flip side, some commodities transacted in the market are not available or can not be easily acquired unless the demand is high enough. Under this proposition, some consumers rise and find their own solution to meet the services at a reasonable cost or at an adequate level. The commonly adopted way is to establish a cooperative, and it stirs purchasing power by pooling resources and further bargains price and service quality. As a consumer cooperative, housing cooperatives notably found in rural towns enable the elderly to continue independent living. This study is to take a closer look at residential life of the rural elderly in housing cooperatives. Utilizing in-depth focus group interviews with 40 residents in four housing cooperatives, this qualitative research draws main factors affecting the decision to move in, residential assessment, and strengths and weakness of living in a housing cooperative. The primary factor influencing the moving decision is to continue to independent living in a familiar community, and the bottom line is planning ahead. Frailty and bereavement are found to be the leading occasions for them to move. The participants are satisfied with the independent living arrangement, and particularly, cited such features as safety and security, elderly-friendly design, common spaces, freedom, social activities and efficient living. Also, it is stated that some cooperative natures such as control over the property and giving a voice on management render positive impacts on the satisfaction with communal living. In spite of all the benefits and strengths, participants face with a public notion that an independent living arrangement like a housing cooperative has never done before in rural towns, so that most people recognize it as part of dependent living arrangements like nursing home.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.301-308
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• 2017

This paper proposes a disturbance observer based controller design method for generating and yawing control of windturbine with two cooperative generators. Windturbine system with two cooperative generators is a distinct structure in which the wind energy supplied by blade axis is converted into electrical energy by two cooperative generators. In this structure, two generators can be controlled independently and therefore they can generate power, simultaneously performing yawing control of nacelle without extra yawing mechanism by cooperatively controlling generating load in appropriate manner. Using this structural trait, this paper designs a disturbance observer based controller that enables the windturbine system with cooperative generators to generate and yaw stably, and verifies the performance of the controller experimentally by applying it to a small-scale windturbine system with the same structure.