• 터널과지하공간
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• 제22권1호
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• pp.1-11
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• 2012

열에너지 저장은 고온 또는 저온의 열에너지를 임시 저장하는 것으로서 에너지 수요와 공급 사이의 불균형을 줄일 수 있고, 이를 통해 에너지를 절약하고 에너지 이용효율을 향상시킬 수 있다. 특히 간헐적으로 에너지를 생산하는 신재생에너지의 경우 에너지 저장 장치와의 조합은 필수적이다. 또한 지하 암반의 낮은 열전도도와 높은 열용량을 이용하여 지하에 열에너지를 저장하는 경우 열손실을 최소화하여 추가적인 효율 향상이 기대된다. 본 고에서는 지하 열에너지 저장 기술을 조사 분석하고 스웨덴에 암반공동내 열에너지 저장 사례를 소개하였다.

• Journal of information and communication convergence engineering
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• 제8권3호
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• pp.273-276
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• 2010

Opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• 교육시설
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• 제14권1호
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• pp.14-22
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• 2007

This study is to examine the present situation relating to the works for landscape architecture in the universities of Korea with the aim of efficient landscape architecture in university campus and to provide the fundamental data of the logical and organized approach to the plans for campus landscape architecture. A survey of the staffs for landscape architecture in 20 national universities all over the country was carried out on the lot utilization ratio of each university, the development of landscape architecture department and its professionals in universities, the establishing status of the plans for landscape architecture of each university, and the satisfaction level of landscape architecture staffs. The results show that most universities pay a little attention to the whole campus landscape architecture according as they don't conduct the systematic works for landscape architecture and some which are done partially attach importance only to maintenance work such as simple controls of open space and trees. As a consequence, the active utilization of potential lot on campus and the organization of professionals and specialized teams for landscape architecture should be realized in order to make the works for campus landscape architecture effective. Besides, in policies, it is thought that the development of general plans and budgets for landscape architecture at the stage of establishing the medium-and long-tenn growth schemes of the universities is required.

• International Journal of Fluid Machinery and Systems
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• 제7권1호
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• pp.1-6
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• 2014

The propellant acquisition vane (PAV) is a key part of a vane type surface tension propellant management device (PMD), which can manage the propellant effectively. In the present paper, the fluid transportation behaviors for five PAVs with different sections were investigated by using microgravity drop tower test. Further, numerical simulation for the propellant flow in a PMD under microgravity condition was also carried out based on VOF model, and showed the similar flow pattern for PAVs to the experiment. It is noted that the section geometry of PAVs is one of the main factors affecting the fluid transportation behavior of PMD. PAVs with bottom length ratio of 5/6 and 1/2 have larger propellant transportation velocity. Based on the experiments, there were two stages during the process of propellant transportation under microgravity environment: liquid relocation and steady transportation stage. It is also recognized that there is a linear correlation between liquid transportation velocity and relative time's square root. Those results can not only provide a guideline for optimization of new vane type PMDs, but also are helpful for fluid control applications in space environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4776-4798
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• 2015

The location selection of virtual machines in distributed cloud is difficult because of the physical resource distribution, allocation of multi-dimensional resources, and resource unit cost. In this study, we propose a multi-object virtual machine location selection algorithm (MOVMLSA) based on group information, doubly linked list structure and genetic algorithm. On the basis of the collaboration of multi-dimensional resources, a fitness function is designed using fuzzy logic control parameters, which can be used to optimize search space solutions. In the location selection process, an orderly information code based on group and resource information can be generated by adopting the memory mechanism of biological immune systems. This approach, along with the dominant elite strategy, enables the updating of the population. The tournament selection method is used to optimize the operator mechanisms of the single-point crossover and X-point mutation during the population selection. Such a method can be used to obtain an optimal solution for the rapid location selection of virtual machines. Experimental results show that the proposed algorithm is effective in reducing the number of used physical machines and in improving the resource utilization of physical machines. The algorithm improves the utilization degree of multi-dimensional resource synergy and reduces the comprehensive unit cost of resources.

• 한국멀티미디어학회논문지
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• 제21권4호
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• pp.499-512
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• 2018

The application of analytical techniques for the rational determination of problems arising from management science and corporate management. In a way that is the opposite of the repair plan that can predict accurate results is increasing utilization of the complex-based analysis methodology. In this study, we examined the application of physical space and the methodological utilization of the pedestrian model analysis that applied the simulation to the Health Checkup Center. The conclusions are as follows. First, the spatial analysis and measurement for empirical research has confirmed that the efficiency assessment through the pedestrian model simulation can lead to an objective evaluation. Second, it seems to be able to reduce the queue through a change in the number of services of the low-pressure and the hearing laboratory, the recovery room with a high proportion of male disturbances and relatively long use time. The third, the spatial density analysis and the time required to reduce the density change in comparative analysis, and the spatial layout changes, the increase in the capacity of 80 people, approximately 16 minutes to shorten the process duration.

• 한국도서관정보학회지
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• 제23권
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• pp.109-145
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• 1995

This study is to find out general problems a n.0, ppeared in the management and utilization of these and dissertation and to suggest some recommendations, through the survey and analysis on the Korean university libraries. Questionnaires were sent to 109 university libraries which offer master's and doctoral degrees, during the period between March 7 and March 27, 1995. Responded questionnaires of 91 libraries (about 83%) were processed using SAS. The results of this survey can be summarized as follows: 1. Most of Korean university libraries have the collections of theses and dissertations ranging from less than 10,000 volumes (27 libraries ; 32.1%) ; 10,000 to 30,000 volumes (20 libraries ; 25.0%) ; to more than 80,000 volumes (16 libraries ; 19.0%). The largest collection was around 200,000 volumes. 2. In the management of them, 35 libraries (38.5%) were active in collecting them, but 56 libraries (61.5%) were not active, mainly for the shortage of manpower and the space problems. In 62.6% of libraries, they are arranged with the books. And 51.3% of libraries process them in less than one month. 46 libraries (52.9%) computerize their system, and among them 40 libraries (87%) establish their own databases. 3. The collections of theses and dissertations are called by various name, including periodical room, theses room, reference reading room etc. reaching to 15 kinds. 71 libraries (78.0%) adopt open system, and 17 libraries closed system ; and 2 libraries (3.2%) partial open system. 62 libraries (68.1%) arrange them in the order of call number, while 20 libraries (31.9%) by other criteria.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.226-231
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• 2011

This study set out to review the air current fluidity in exhaust common ducts by installing an inlet pipe at a leisure space in the PS(Pipe Shaft)room for the sake of wind power generation with kitchen and bathroom exhaust common ducts of all the equipment and air conditioning shafts in high-rise apartment. The air current functionality of kitchen and bathroom exhaust common ducts was reviewed by analyzing wind velocity changes according to changes to the area of exhaust common ducts through a simulation, changes to the wind velocity of the kitchen hood by applying an external inlet pipe, changes to the usage factor of exhaust common ducts, and changes to wind velocity by altering the form of the ventilator at the bottom of the old exhaust common duct. It was a basic study on the utilization of exhaust wind velocity in exhaust common ducts.

• 대한지리학회지
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• 제34권3호
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• pp.247-264
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• 1999

In this study, I investigate how city parks have been created, and what are some characteristics of the location and function of 69 city parks in Tokyo. The city parks in Tokyo have been made in three patterns. The first is planned parks which have been created as a urban facilities considering the scales and types. The second is memorial parks which have been made to memorialize the national monumental event or to preserve natural and cultural resources. The third is public property parks which have been made by occurrence of public vacant land which is resulted from the grant of Royal Garden, restoration of public rented ground, producton of reclaimed land, utilization of dry river bed. The city parks can be classified in five patterns according to distance from CBD and park area. The first is central parks which have historical characteristics strongly. The second is planned parks that are specialized functionally. The third is large scale urban edge parks which are located in the edge of 23-Gu(district) in Tokyo. The fourth is hill parks which have natural characteristics strongly. The fifth is waterside parks that are located along a lake, a pond, a river, or artificial waterside facilities. From this study I have found out that a great effort has been made to activate the utilization of parks for residents in Tokyo, through mnagement goals and ways of parks, composition and chatacteristics of park facility resources, various Events, residents participation in undertaking of parks.

• 산업경영시스템학회지
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• 제46권1호
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• pp.68-75
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• 2023

In an automotive plant, an automated storage and retrieval system (ASRS) synchronizes material handling flows from a part production line to an auto-assembly line. The part production line transfers parts on small-/large-sized pallets. The products on pallets are temporarily stored on the ASRS, and the ASRS retrieves the products upon request from the auto-assembly line. Each ASRS aisle is equipped with narrow-/wide-width racks for two pallet sizes. An ASRS aisle with narrow-/wide-width racks improves both storage space utilization and crane utilization while requiring delicate ASRS aisle design, i.e., the locations of the narrow-/wide-width racks in an ASRS aisle, and proper operation policies affect the ASRS performance over demand fluctuations. We focus on operation policies involving a common storage zone using wide-width racks for two pallet sizes and a storage-retrieval job-change for a crane based on assembly-line batch size. We model a discrete-event simulation model and conduct extensive experiments to evaluate operation policies. The simulation results address the best ASRS aisle design and suggest the most effective operation policies for the aisle design.