• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.277-285
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• 2005

In this paper, we propose the occupied bandwidth(OBW) measurement method for effectively measuring the 99 $\%$ OBW at monitoring station. In order to validate the measurement results obtained from the proposed measurement method, the modified adjacent channel power ratio(MACPR) is herein defined as the formula which was suitable for applying to the OBW measurement of 8-VSB DTV signals. It has been found that the MACPR is a good measurement parameter applicable for the proper site selection of monitoring station and the effective OBW measurement of 8-VSB DTV signals should be made for MACPR$\geq$35 dB with 600 measurement trials. The proposed measurement procedure is herein given and proven to effectively be applicable to the OBW measurement of terrestrial 8-VSB DTV signals on the air.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.19-27
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• 1999

This paper propose a contention resolution policy featuring dynamic change of the threshold for the occupancy of the input buffer for an input buffering ATM switching architecture and its hardware implementation strategy. The strategy is provided with the aim of the simple structure that achieves the reduction of the signal path and the power consumption. The threshold is changed dynamically every time slot based both the arrived of cells and the cell service resulting from the contention resolution. The performance on the cell loss of the proposed policy is performed and compared with the conventional policy under the diverse traffic conditions through both the analysis based ont the Markov chain and the simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.2
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• pp.99-113
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• 1992

In general, TDMA and FDMA have been used for multiple access communication methods. Recently. However, ALOHA and CSMA protocols came to exist as new schemes for VSAT data networks and LANs, respectively. These schemes are proven to be effective for packet switched communication systems that has bursty traffic but packet collisions. In this paper we analyze capture statistics arising from fading channels in packet radio communication systems in the context of ALOHA protocol. We derive general results of the exact form of capture probabilities and present numerical data for wide range of fading parameters. Since the capture probabilities are found to approach zero when the number of transmitted signals become larger, we are able to determine the achievable channel throughput by a least squares fitting of an exponential-type function to the probabilities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10A
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• pp.987-996
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• 2008

In this paper, the conventional anti-collision algorithms, such as Channel Monitoring algorithm and Pulse Protocol algorithm are analyzed. To decrease tag identification time, and increase system throughput and efficiency, we propose a new reader anti-collision algorithm, Pulse Protocol-based Hybrid Reader Anti-collision Algorithm, using Slot-occupied Probability under dense reader environment. The proposed algorithm uses Slot-occupied Probability to improve the performance of Pulse Protocol Algorithm. That is, A reader checks Slot-occupied Probability after generating random backoff time. If Slot-occupied Probability is greater than 0, it uses another new random backoff time to avoid reader collision. We also compare the performance of the proposed algorithm with those of Channel Monitoring and Pulse Protocol algorithms in respect of identification time system throughput, and system efficiency. Simulation results show that the proposed algorithm has an increment of 5% of identification time and system throughput as increasing the number of readers.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.493-501
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• 2014

An automated lifting vehicle(ALV) used in an automated container terminal is a type of unmanned vehicle that can self-lift a container as well as self-transport it to a destination. To operate a fleet of ALVs efficiently, one needs to be able to determine a minimum-time route to a given destination whenever an ALV is to start its transport job. To find a route free from any collision or deadlock, the occupation time of the ALV on each segment of the route should be carefully scheduled to avoid any such hazard. However, it is not easy because not only the travel times of ALVs are uncertain due to traffic condition but also the operation times of cranes en route are not predicted precisely. In this paper, we propose a routing method based on an ant colony optimization algorithm that takes into account these uncertainties. The result of simulation experiment shows that the proposed method can effectively find good routes under uncertainty.

• Korea Real Estate Review
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• v.28 no.1
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• pp.39-52
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• 2018

The purpose of this study was to analyze the housing tenure choice decisions of older households, with focus on the activity constraints of the householders. For analysis, the probit model based on the data of the householders over 55 years of age from the 2015 KLIPS data was implemented. The research findings indicate that the ownership choice probability decreases when the head of the household has activity or social activity constraints. If there is an activity restriction, it is considered that the possibility of self-residence will be low due to the increase in medical expenses, the possibility of participation in economic activities will be low, the possibility of early retirement will be high, and the income will decrease. Therefore, if the head of the household has a personal or social activity constraint, such case is more likely to be categorized as falling under the poor residential group. This result suggests that the activity constraint can be utilized as a useful index for the housing welfare policy considering physical vulnerability.

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.208-216
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• 1993

The territorial behavior of the naked goby, Gobiosoma bosci, was observed in 80-liter aquaria. Social behavior was observed for an extended time in daily observation periods. Individuals of G. bosci, regardless of size and sex, exhibited agonistic behavior. The aggresive behaviors of approaching, threatening, attacking, and fighting were recorded as agonistic behavior. All individuals are capable of changing their color and camouflaging themselves by matching the color of bottom. Especially, the resident and the intruder are of the same size, the fighting duration was prolonged and the variability of coloration was at its peak.

• 한국벤처창업학회:학술대회논문집
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• 2020.11a
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• pp.89-93
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• 2020

산업이 발전함에 따라 타인의 아이디어에 대한 가치가 점점 높게 인정되고 있다. 아이디어는 지식재산권으로 보호가 될 수 있으며, 특히 발명에 대한 아이디어는 특허로 보호된다. 특허법상 요건에 맞는 발명은 특허권으로 보호될 수 있고, 특허권으로 보호되는 발명은 특허권자만이 실시할 수 있는 독점적인 지위가 인정된다. 기업들은 새롭게 개발한 기술을 특허권으로 보호하기 위해 많은 노력을 기울이고 있는데, 이러한 특허가 기업의 매출에 영향을 미치는지를 분석하기 위해 다양한 연구들이 계속되고 있다. 본 연구의 목적 역시 중소기업이 개발한 새로운 기술에 대한 특허취득활동이 기업의 매출과 같은 경영성과와 기업이 속한 기술분야에서 시장점유율에 유의미한 영향을 미치는지를 조사하고, 시장점유율 상승이 기업의 매출증진에 매개효과를 일으킬 것인지, 기업이 속한 산업분류가 특허취득활동의 경영성과 등에 미치는 영향에 조절효과를 일으킬 것인지에 대해 분석 하는데 있다. 본 연구에서는 중소기업의 특허취득활동이 시장점유율과 경영성과에 미치는 영향을 분석하였다. 아울러 특허취득활동이 시장점유율과 경영성과에 미치는 영향력이 산업분류에 의해 조절되는지 여부과 시장점유율이 경영성과에 미치는 매개효과를 조사하였다.

• Archives of design research
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• v.18 no.4 s.62
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• pp.287-296
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• 2005

The street image in a business area is so much affected by Facade that the front side of a roadside building makes. Recently, for the indiscreet and intemperate advertising signboard of the front side of roadside buildings, a streetscape becomes more disordered than before, so now we need to do research about signboards of roadside buildings for a streetscape image. In this research, we focused on a streetscape with difference of occupation density of signboard in the business area via investigation and analysis about occupation density of signboards of the front side of roadside buildings, and we suggested optimum occupation density of signboards for supporting the road image positively. An object of research is the street in the business area that has many pedestrians and active passing zone of cars. We investigated and analyzed how to feel street images on the rate of occupation density of roadside building's signboards of in the chosen street. As a result of using an adjective that we use for estimating street view images for extraction of street images, we could know 2 factors. We named that one is the image of recognition, and the other is the image of feelings. We knew that signboard density of street of heavily recognized images is from 20% to 30% and, signboard density of street of heavily feeling images is from 50% to 60%. We also could know that people feel both images of recognition and images of feeling in specific density, 30 to 50%. Through this result of research, we can suggest Facade on signboard density with the recognition and the feeling and use images of the street view as materials to be more specific and more special.

• Aerospace Industry
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• v.53
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• pp.30-33
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• 1997

미국의 보잉사와 록히드의 양사가 여타 항공기 제조업자를 합병 혹은 흡수하여 사실상 맘모스 기업으로 발판을 굳힘에 따라 유럽세인 에어버스를 비호하는 유럽연합측이 실질적인 시장 독점을 위한 기업연합이라고 항의하는 등 국제 항공기 시장을 놓고 항공기 제조업계의 경쟁은 갈수록 치열해지고 있다. 한편 지난 6월의 파리 에어쇼를 전후하여 보잉사와 에어버스 양사는 민간 여객기 판매에 더욱 열을 올리고 있으며 그중에도 에어버스사의 세계 시장 절반 점유계획이 크게 돋보이고 있다. 이러한 세계시장의 열띈 기운을 배경으로 항공기 수요의 장기 전망과 시장점유동향에 대하여 그 개관을 알아 보기로 한다.