• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1208-1222
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• 2014

Due to the low utilization and scarcity of frequency spectrum in current spectrum allocation methodology, cognitive radio networks (CRNs) have been proposed as a promising method to solve the problem, of which spectrum sensing is an important technology to utilize the precious spectrum resources. In order to protect the primary user from being interfered, most of the related works focus only on the restriction of the missed detection probability, which may causes over-protection of the primary user. Thus the interference probability is defined and the interference-aware sensing model is introduced in this paper. The interference-aware sensing model takes the spatial conditions into consideration, and can further improve the network performance with good spectrum reuse opportunity. Meanwhile, as so many fading factors affect the spectrum channel, errors are inevitably exist in the reporting channel in cooperative sensing, which is improper to be ignored. Motivated by the above, in this paper, we study the throughput tradeoff for interference-aware cognitive radio networks over imperfect reporting channel. For the cooperative spectrum sensing, the K-out-of-N fusion rule is used. By jointly optimizing the sensing time and the parameter K value, the maximum throughput can be achieved. Theoretical analysis is given to prove the feasibility of the optimization and computer simulations also shows that the maximum throughput can be achieved when the sensing time and the parameter of K value are both optimized.

• Journal of Communications and Networks
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• v.13 no.6
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• pp.664-677
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• 2011

In order to control interference and improve spectrum efficiency in the femtocell and macrocell overlaid system (FMOS), we propose a joint frequency bandwidth dynamic division, clustering and power control algorithm (JFCPA) for orthogonal-frequency-division-multiple access-based downlink FMOS. The overall system bandwidth is divided into three bands, and the macro-cellular coverage is divided into two areas according to the intensity of the interference from the macro base station to the femtocells, which are dynamically determined by using the JFCPA. A cluster is taken as the unit for frequency reuse among femtocells. We map the problem of clustering to the MAX k-CUT problem with the aim of eliminating the inter-femtocell collision interference, which is solved by a graph-based heuristic algorithm. Frequency bandwidth sharing or splitting between the femtocell tier and the macrocell tier is determined by a step-migration-algorithm-based power control. Simulations conducted to demonstrate the effectiveness of our proposed algorithm showed the frequency-reuse probability of the FMOS reuse band above 97.6% and at least 70% of the frequency bandwidth available for the macrocell tier, which means that the co-tier and the cross-tier interference were effectively controlled. Thus, high spectrum efficiency was achieved. The simulation results also clarified that the planning of frequency resource allocation in FMOS should take into account both the spatial density of femtocells and the interference suffered by them. Statistical results from our simulations also provide guidelines for actual FMOS planning.

• Journal of the Korean Geographical Society
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• v.30 no.3
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• pp.311-323
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• 1995

This study attempts to examine the location and district of elementary schools at Chongro-gu. For the convenience of the analysis, the data are analysed with the methods of GIS network model. For the purpose data was collected from Statistical Yearbook of Education in 1994 and Census of Housing and Population in 1990. Results may be summarized as follows. First of all, spatial pattern of elementary school at Chongro-gu shows outward diffusion because of problems, rising of land value, and out-migration of population in the area. Secondly, for the analysis of locational situation this paper uses the data such as population of 5-9 age, the number of housing, accessibility, and land value. The location of elementary school is ciassified into 4 types; the best area, better area, worse area, the worst area. The best area is Pyongchana-dong, Buam-dong, and Ewha-dong and the worst area is Chongro 1ga-dona, Chonaro 2ga-dong and Sechongno-dong. Thirdly, the alternative plans of school district are presented for the maximum equity and efficience, and security of school attendantes. The former emphasizes the minimization of commuting distance, the later emphasizes the minimization of the an comfortable facilities such as main streets in school district. Present school district which is based upon administrative dong should be changed to roadbased school district.

• Journal of the Korean association of regional geographers
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• v.8 no.4
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• pp.492-512
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• 2002

The daily life activities of primary school children have been increasingly diversified. This research examined the spatio-temporal characteristics of primary school children's daily life activities. The time allocation of primary school children's daily activities was monotonous. They tended to spend most of their time in school activities, private lessons after school, and studying at home. The daily trip to school has been diversified as the result the of increase in the number of double-income families, car owners, facilities for pastime, and educational facilities for private lessons after school. The selection of educational facilities for private lessons was strongly influenced by accessibility to the residence because of the limited time budget of primary school children and the controlled trip behavior by parents. The leisure activities were considered as a minor function and took place in the interval of performances of study-related activities. The high proportion of leisure activities was found in the indoor play. The amount of the time for leisure activity was very insufficient. The spatial range and time budget were strongly influenced by the institutional conditions of parents.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.328-331
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• 2007

In this paper, the capacity of the clustered response model for correlated MIMO-OFDM fading channel is investigated. We compare the capacities achieved by correlation at receiver and achieved by correlation at both the transmitter and the receiver for the case where the channel is known and unknown at the transmitter are considered. It is found that the capacity achieved by correlation at receiver is better than the other. It is also shown that the capacity using the water-filling methed is larger than that using the uniform power allocation due to the water-filling gain. But it is negligible when the number of clusters is over the maximum rank of the sum correlation matrix and SNR is high.

• Korean Institute of Interior Design Journal
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• v.17 no.6
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• pp.161-169
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• 2008

Recently, appearance is recognized as competitiveness as well as self expressing means, so understanding of general people have been rapidly changed. Also, since modem people have interest in an operation as well as various cosmetic treatment fields, a plastic surgery clinic is expanding its region to laser treatment and skin care for modem people. However, the plastic surgery clinic is not located in a building for only hospitals, but located in general neighborhood living facilities or an office building, so medical treatment is performed at the place. It is often found that a building plan can not conform to conditions that the hospital requires. This study is to understand a plane deciding factor of the plastic surgery clinic by analyzing it in a limit of building space and functional aspects of the plastic surgery clinic. A study method is first to investigate space composition according to the function, area allocation according to the function and a space privacy region after classifying study objects into large, middle, small scales so as to understand a functional role of the plastic surgery clinic, and secondly to analyze on the base of length of long and short edges of space and a moving line system after classifying common space types of the plastic surgery clinic through plane analysis of the study objects. As a result of the study, functional space difference according to the scale was shown, and the common space types were affected by length of the long and short edges, and it can influence space composition.

• Korean Journal of Social Welfare
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• v.69 no.4
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• pp.99-125
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• 2017

Recent social studies on space have focused on changing the social relations that activate in space. In general, these studies have been based on the concept of social space on which is grounded the power-relation analysis such as power, oppression, resource allocation, and so on. Social work practice has traditionally recognized the importance of the environment surrounding human beings. Nonetheless, social work practice has tended to comprehend space in a neutral and abstract way because it has insufficiently considered modern spatial theories. For this reason, this study focusing on Lefebvre's social space theory reviewed the contemporary discourses on space in the area of social work practice. Following the review, this study attempted to establish the concept of "Space-based Social Work Practice". Specifically, this study analyzed the actual cases in social work field and explored the applicability of "SSWP". According to the results, this study delivered the implications of Space-based Social Work Practice as an alternative method and suggested the practical direction of SSWP.

• Design Convergence Study
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• v.16 no.3
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• pp.103-118
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• 2017

It is expected that the integrated control service of the public sector will be increased for the safety of citizens in the future. Therefore, In this study, we analyzed the classification of CCTV control center and the characteristics of interior design. The survey was conducted at eight control centers in Seoul that were constructed since 2007 and analyzed according to the criteria of general matters, services, spatial basic information, spatial structure, and internal structure. The results of the survey are summarized as follows. Based on the results of the study, the Integrated Control Center is a space where the ratio of the physical environment is not high but performs important tasks for the citizens of the city, which are operated 24 hours a day, and security and security. It is characterized by the efficient space allocation for the treatment, the design of the moving line, and the connection according to the urgent work flow. The results of this study are expected to be used as basic data for other integrated control center environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.15-24
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• 2022

At present, there are few studies on signal control of pedestrian traffic flow and non-motor traffic flow at intersections. Research on the optimization scheme of mixed traffic flow signal control can coordinate and control the overall traffic flow of pedestrians, non-motor vehicles and motor vehicles, which is of great significance to improve the congestion at intersections. For the traffic optimization of intersections, this paper starts from two aspects: channelization optimization and phase design, and reduces the number of conflict points at intersections from spatial and temporal right-of-way allocation respectively. Taking the classical signal timing method as the theoretical basis, and aiming at ensuring the safety and time benefit of traffic travelers, a channelization optimization and signal control scheme of the intersection is proposed. The channelization and phase design methods of intersections with motor vehicles, non-motor vehicles and pedestrians as objects are discussed, and measures to improve the channelization optimization of intersections are proposed. A multi-objective optimization model of intersection signal control was established, and the model was solved based on NSGA-II algorithm.

• Journal of Environmental Impact Assessment
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• v.30 no.5
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• pp.297-304
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• 2021

The environmental impact assessment(EIA) project in Korea has undergone changes and revisions in various evaluation items for about 30 years after the introduction of the Environmental Conservation Act (1997). However, despite the importance of land use evaluation items under the current EIA Act, there are insufficient studies to consider. Therefore, this study focused on the land-use evaluation items based on the EIA guidelines, reviewed 90 of the evaluation documents and consultation documents, and tried to suggest implications and supplementary points forthe domestic EIA land-use evaluation items. As a result, the paradigm was changing from land efficiency centered on development in the past to land efficiency centered on the natural environment and resource conservation. However, in spite of the manual for fitting the paradigm change, opinions on the conservation of the natural environment are still being drawn in the consultation document, so it needs improvement. Two improvements in the impact assessment process suggested in this study are the establishment of standardized spatial data and a quantitative impact and reduction method evaluation tool based on it. In particular, there is a need for a plan evaluation tool for land use arrangement and distribution that can solve the needs of minimizing damage to the natural environment and securing green space and a green network.