• Journal of the Korea Society of Computer and Information
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• v.19 no.9
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• pp.177-184
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• 2014

This study suggested the necessity of efficient volunteer management plan and continuous volunteer expansion plan to enhance the continuity of volunteer activity by local government and induce more systematic and stable volunteer activity. As a prior concrete plans for volunteer expansion, this study suggested establishing the incentive for expanding continuous volunteers through coexisting and cooperation, enhancing the propulsion will and providing an institutional strategy of local and metropolitan government heads, improving volunteer's internal capability, and reinforcing administrative support and financial aid. Also this study emphasized the effectiveness of various volunteer-related matters such as daring support and investment to drastically expand continuous volunteers and their activities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.1
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• pp.55-62
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• 2009

Relatively low cycle performance of a conventional $CO_2$ system is partly due to significant increase in friction loss in the expansion process, since the pressure drop across the expansion device is considerably large compared to a conventional refrigeration cycle. To recover friction loss and increase refrigeration effect by providing isentropic expansion, a rotary vane type expander has been designed. Performance of the designed expander has been investigated by numerical simulation. With the pressure condition of 9 MPa/4.5 MPa and inlet temperature of $35^{\circ}C$, volumetric, isentropic, and mechanical efficiencies of the expander are calculated to be 58.1%, 101.1%, and 78.8%, respectively, resulting in total expander efficiency of 46.3%. With this expander, COP of a $CO_2$ refrigeration cycle is estimated to be improved by about 14%.

• Journal of The Korea Institute of Healthcare Architecture
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• v.7 no.1
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• pp.45-55
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• 2001

In the 20th Century, the genera1 hospitals in Korea had changed in Qualitative and Quantitative aspects, The former would include such as the development of medical skills, equipments, and network system, The expansion of hospital space, increased numbers of hospitals and greater demands of medical attention from the public would be included in the latter, These various changes have been related to external forces such as the growth of the population, the changes in medical policy, the growth of G.N.P, the continuing discovery of new illnesses, the changes in architecture policy, and et cetera. Particularly, the hospitals built in 1970's and 80's have been expanded and renovated to cover the shortage of space, aged facilities, and the changes in hospital atmosphere. Thus, we hope that this study would provide appropriate data for master plans for new medical facilities as well as expansion and renovation data for old ones.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.574-575
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• 2007

This paper proposes a method for choosing the best transmission system expansion plan using nodal/bus delivery marginal rate criterion ($BMR_k$) defined newly in this paper. The objective method minimizes a total cost which is an investment budget for constructing new transmission lines subject to the $BMR_k$ which means a nodal deterministic reliability level requirement at specified load point. The proposed method models the transmission system expansion problem as an integer programming problem. It solves for the optimal strategy using a branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Test results on an existing 21-bus system are included in the paper. It demonstrated the suitability of the proposed method for solving the transmission system expansion planning problem in competitive electricity market environment.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.297-300
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• 2004

This paper proposes a method for choosing the best composite power system expansion plan considering probabilistic reliability criterion. The proposed method was modeled as the minimization of the investment budget (economics) for constructing new transmission lines subject to not only deterministic(demand constraint) but also probabilistic reliability criterion(LOLE) with considering the uncertainties of the system elements. This is achieved by modeling the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a probabilistic theory based branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Although the proposed method is applied to a simple sample study, the test results demonstrate a fact that the proposed method is suitable for solving the power system expansion planning problem subject to practical uncertainties for future.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.68-71
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• 2009

All-IP network requires change of the existing IP network engineering methods as the convergence service market between communication and broadcasting industries using IP network is growing rapidly. Especially the video services like IPTV require more strict transmission quality and higher bandwidth than the existing data services. So it is difficult to design All-IP network by the over-provisioning method which used to be used for the existing IP network design. It also requires a heavy investment which becomes one of big obstacles to the IPTV service expansion. In order to reduce the investment costs, it is required to design an optimized network by maximizing the utilization of the network resources and at the same time maintaining the customer satisfaction in terms of service quality. In this paper, we first analyze the effects of IPTV traffic on the existing internet. Then we compare two traffic engineering technologies, which are dimensioning without admission control and dimensioning with admission control, on the All-IP network design by simulation. Finally, we suggest cost effectiveness of traffic engineering technologies for designing the All-IP network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.727-734
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• 2008

Recently, Network technology evolve out of expansion a scale of Network and development various Service. also Hacking skill. We have applied to various Security Systems to make a counterattack on this hacking skill. and A Firewall among these security systems is very effective a defense against in the Outbound Network attack. so we need certainly a Firewall to protect a network. But this Conventional Firewall has an directly effect on reduction to the Performance and Security of Inbound Network. and have no effect on a Inner Network Attacking. In this paper, I propose to a "Functional Firewall" as a Secure Objects for the enhancement Performance and Security of Inbound Network.

• Journal of The Korean Association For Science Education
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• v.40 no.6
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• pp.631-648
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• 2020

As an attempt to consider what to pay attention to in science learning, this study was conducted with the aim of discussing the meaning of science learning as a heterogeneous network. As a result of theoretical investigation, the characteristics of the heterogeneous network were described in three aspects: heterogeneous composition, existence by relations, and construction and change by translation. And it was discussed that science learning also has these characteristics of heterogeneous network. Relating to what to pay attention to in science learning, it was also discussed that science learning as a heterogeneous network requires us to pay attention to the elevation of things, the concept as a punctualized heterogeneous network, and the construction and expansion of heterogeneous network with neonadeuri of 'unripe' and 'ripe'. Finally, several suggestions for the science learning were given.

• Information and Communications Magazine
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• v.9 no.1
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• pp.37-42
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• 1992

This paper presents a multi-purpose digital exchange which can be used as a private branch exchange(PBX) or a rural exchange(RX) or an exchange for the private special network. This new idea provides various features, reduced cost of installation and operation, easy expansion, replacement and relocation or reuse for another purpose at other locations.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.135-146
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• 2004

For improving the effectiveness of travel information, some rational paths are needed to provide them to users driving in real road network. To meet it, k-shortest path algorithms have been used in general. Although the k-shortest path algorithm can provide several alternative paths, it has inherent limit of heavy overlapping among derived paths, which nay lead to incorrect travel information to the users. In case of considering the network consisting of several turn prohibitions popularly adopted in real world network, it makes difficult for the traditional network optimization technique to deal with. Banned and penalized turns are not described appropriately for in the standard node/link method of network definition with intersections represented by nodes only. Such problem could be solved by expansion technique adding extra links and nodes to the network for describing turn penalties, but this method could not apply to large networks as well as dynamic case due to its overwhelming additional works. This paper proposes a link-based shortest path algorithm for the travel information in real road network where exists turn prohibitions. It enables to provide efficient alternative paths under consideration of overlaps among paths. The algorithm builds each path based on the degree of overlapping between each path and stops building new path when the degree of overlapping ratio exceeds its criterion. Because proposed algorithm builds the shortest path based on the link-end cost instead or node cost and constructs path between origin and destination by link connection, the network expansion does not require. Thus it is possible to save the time or network modification and of computer running. Some numerical examples are used for test of the model proposed in the paper.