• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.643-646
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• 2007

As increase of the land price at downtown area, it makes people more and more interested of improving the space utilization such as makes buildings bigger, deeper and higher. Therefore, the importance of the underground construction which is the basic principle has been increased. As constructors have to complete underground construction as soon as possible with the minimum costs, they concentrate on the whole process of underground structure. Although they makes every these efforts, construction failure still happen because of the uncertainty of the condition of soil and the unexpected danger of underground construction. To make matter worse, there are only some examples without detailed information like 'how much this breakdown damage to the construction?' so it is the anther problem that most of people doesn't recognize the economical negative impact of underground structure breakdown. This report would make people understood the importance and risk of the underground construction by showing some analysis which was assumed from the real accidents.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.1039-1042
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• 2007

The number of vehicle has been increased due to growth of economy. Consequently, the needs for parking area has been increasing. there is a serious problem in aged-apartments. It result from observing a parking lot law at that times. That is the reason why residents demand parking lot expansion. Parking lot addition is being studied on a lots different standpoint to solve the present parking lot condition. Parking lot expansion is limited by housing complex characteristics. This study analyzed the housing complex characteristics of aged-apartment. It is analyzed that the number of house holders, distance between buildings, and level of site for finding housing complex characteristics. The result are as follows. the complex lower than 300 households is about 35% in the Number of households. The buildings which has a moving distance from 41m to 50 is nearly 23%. Them the 멕스둣 house located on the flat is 82%. This study will become a reference data for the parking lot expansion.

• KIEAE Journal
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• v.10 no.5
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• pp.159-164
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• 2010

High-rising buildings are a sort of solution to recent cities. Till now real estate development was concentrated in new development on vacant lots, and it resulted urban sprawl. Generally large cities are confronted with the exodus of industry and population from city. High-rising buildings solve many problems associated with this problem. The purpose of this research is to identify the effect of super high-rise mixed use building project process on apartment price. For this study, the hypothesis is that price of apartments is influenced by project process of super high-rise mixed use building. The study concerned 4 variations of project process that is building permits stage, sale stage, construction starting stage and stage of moving into building. The target projects of buildings are selected by number of floor(over 40 floors) and construction time. And 48 apartment complex are selected around super high-rise mixed use building. This study uses hedonic price function to analysis effect of project process of super high-rise mixed use building. A price of apartments is defined as a dependent variable. Characteristics of residence, complex, district and super high-rise building are defined as independent variables. The results are as follows; first, there is no error in price model of this study. Second, it is found that apartment price was influenced negatively by building permit stage and sale stage of super high-rise mixed use building. But that was influenced positively by construction starting stage and stage of moving into building of that. Third, as the project process of super high-rise mixed use building was proceeded, price of apartments was increased.

• KIEAE Journal
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• v.11 no.2
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• pp.75-82
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• 2011

In Korea, the ratio of population in urban areas used to be only 50.1% in 1970, but with the value risen to 90.8% in 2009, urbanization is going on rapidly. Urbanization, which occurs by the rampantly planted buildings, has become major source of raising building density, changing wind direction and reducing wind amount, and such reductions are affecting even inside the building. In each year, among the total energy consumption in Korea, residential portion takes up significant ratio, and specifically the ratio of apartment house is shown to be highest. In order to solve such problem, many studies are being conducted for the improvement of natural ventilation performance. The natural ventilation performance of apartment house are significantly determined by the characteristics of external and internal structure, but in macroscopic perspective, the performance is established fundamentally by the layout characteristics of the main building of the apartment house in preparation for wind conditions. So far researches on raising the thermal comfort through elevation of ventilation performance have been conducted actively, but many of them propose only theoretical concepts deduced through wind path analysis, and do not include any indicator to measure ventilation performance simply only with area data from layout planning stage. Therefore, in this study, gap ratio a wind field measuring indicator was developed, and after the ventilation characteristics by layout types and main building uniformity were identified, the scope of gap ratio efficient for ventilation and that of uniformity were clarified, followed by verification through simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.631-639
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• 2016

Wi-Fi Direct standard technology has been widely deployed on the recently manufactured products such as smart phone, smart monitor, TV, set-top box, and gaming console, and it was published from Wi-Fi Alliance with the name of Wi-Fi Peer-to-Peer Technical Specifications (v1.4, 2014) for direct connection on the wireless communication environment. However, the connection process of this standard needs 5 to 10 seconds so it can lead to user's inconvenience as well as long delay for connection. From the focus of that this problem was derived from long discovery process composed of Scan and Find, as a result, the proposed scheme on this paper modified and adapted Scan and Find processes with reassembling steps of them for reducing the connection delay. In addition, the analysis and experiments were progressed for the evaluations of the proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.220-230
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• 2011

Mobile RFID which integrates mobile network with RFID technique is the technique to get the information of products by transmitting the identifier through mobile network after reading the identifier of RFID tag. It attached on the equipment as the mobile phone. However, mobile RFID has the privacy-related problem among requested secure problems required from the existing RFID. In this paper, the random key created by mobile RFID reader and Tag during the inter-certificating and initialization procedure for mobile RFID users to receive tag information from backend server securely is divided into random sizes and any information on the tag which requires the protection of privacy shouldn't be provided to anyone. In performance analysis, previous protocol used modulo operation in registration and login computation. But the proposed protocol has higher efficiency in saving space and computation volume than MARP scheme and Kim. et. al scheme because our protocol is accomplished by mutual authentication and registering user information through one-way hash function.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8B
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• pp.954-961
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• 2011

To apply Wi-Fi technique to the Broadcast field, we have to study features of IEEE 802.11 Broadcast packet. IEEE 802.11 Broadcast technique cannot guarantee successful packet delivery than IEEE 802.11 Unicast. A promising solution to this problem is the use of FEC(Forward Error Correction) mechanisms. However, the adjustment of the FEC redundancy rate is not a trivial issue due to the dynamic wireless environment. In order to explore the above issues we conducted an experimental study of the packet loss behavior of the IEEE 802.11g protocol. In order to study, we implemented a broadcast test bed. Based on the experimental results, we provide guidelines on wireless lan parameters(packet size, transmission rate(11g), background traffic). From this experimental study, we provide FEC redundancy rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.3
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• pp.143-150
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• 2014

In this paper, we propose an energy efficient and delay guaranteed node scheduling scheme inspired by biological systems, which have gained considerable attention as a computing and problem solving technique. With the identification of analogies between cellular signaling systems and WSN systems, we formulate a new mathematical model that considers the networking challenges of WSNs. The proposed bio-inspired algorithm determines the state of the sensor node, as required by each application and as determined by the local environmental conditions and the states of the adjacent nodes. A control analysis shows that the proposed bio-inspired scheme guarantees the system stability by controlling the parameters of each node. Simulation results also indicate that the proposed scheme provides significant energy savings, as well as reliable delay guarantees by controlling the states of the sensor nodes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1078-1087
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• 2014

In the conventional centralized mobility management schemes, it can lead to single points of failure, occurrence of a bottleneck, since all data and control are concentrated on the mobility anchor which is located in home network. In the current research of distributed mobility management, it is doing research into distributed mobility management which is supported by distributed mobility anchors. Such schemes do not consider a failure of the mobility anchor. However, it could be an issue under tactical environment since it occur non-service problem due to anchor movement, maintenance, failure, etc. In this paper, we proposed new DMM scheme named T-DMM(Tactical-Distributed Mobility Management) which can support handover even if mobility anchor breaks down. From the numerical analysis, we evaluate signaling cost and handover latency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.2
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• pp.209-216
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• 2013

In this paper, we design and analyze digital retrodirective array antenna (RDA) system in 60GHz wireless communication for low power consumption and high quality. Digital RDA can automatically make beam toward source without information about the direction of incoming signal, this system is able to do low power communication thanks to increased signal to interference noise ratio (SINR) because making the beam toward source can reduce interference signals. The frequency offset seriously arises when millimetric wave band like 60GHz is used to communicate for high-speed transmission. The proposed system is robustly designed to frequency offset through designing digital phase lock loop in order to solve the problem of frequency offset. In this paper, we analyze the performance of the proposed system according to the number of array antenna and frequency offset. striking space.