• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.90-94
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• 2007

Location tracking automation of resources in construction industry is one of the most important procedures to improve construction project performance and reduce the period of construction. Recently, location tracking technologies have proven to be effective in tracking construction materials and equipment in real time through the instrumentality of RFID (Radio Frequency Identification). By using wireless communication and inter-working system between RFID and USN, it is possible that construction engineers receive the location information of construction resources without additional efforts that move the RFID reader to read tags periodically. In the inter-working system, RFID reader delivers the acquired materials information to sensor node which is connected by serial interface. Then sensor node transmits the received data to the data aggregation terminal that is a sink node. The data aggregation terminal can transmit collected data to construction manager who is out of construction site using infrastructure such as CDMA(Code Division Multiple Access) network. The combination model of the two system and field test scenarios are presented in this paper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.761-768
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• 2010

This paper presents an effective method to achieve the wideband waveform for high resolution SAR(Synthetic Aperture Radar) using the frequency multiplication technique. And also this paper analyzes the root causes for the spectral regrowth due to 3rd-order intermodulation in chirp bandwidth expansion scheme using quadrature modulator and frequency multipliers. The amplitude and phase imbalance requirement are defined based on the simulation results in terms of quadrature channel imbalance. This minimizes the degradation of range resolution, peak sidelobe ratio and integrated sidelobe ratio. The wideband chirp generator using the frequency multiplier and memory map scheme was manufactured and the compensation technique was presented to reduce the spectral regrowth of SAR waveform by minimizing the amplitude and phase imbalance. After I and Q channel imbalance adjustment, the carrier level reduces －28.7 dBm to －53.4 dBm. Chirp signal with 150 MHz bandwidth at S-band expands to 600 MHz bandwidth at X-band. The sidelobe levels are reduced by about 8 to 9 dB by compensating the amplitude balance between I and Q channels.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.1
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• pp.1-8
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• 1999

In recent years, concern has been raised about the technique of controlling electrical breakdown by using laser in many fields. Especially, laser has attracted much attention in the Electro-Discharge Machining(EDM) because of its many rrents. 1berefore, this research has been perfonred to obtain fundarrental data for the discharge guide technology by a pulsed Nd:YAG laser which can be awJied to discharge processing machining. 1be experilnnts of laser-guided de discharge have been carried out at low air pressure ranging from 0.2 to 20 torr. The minimum laser-guided de discharge voltage $V_{G.min}$ at the given pressures P and distances d between an anode and a cathode was rreasured It is found that $V_{G.min}$ is much lower than the natural discharge voltage $V_{ND}$, and the values of VGrrin and $V_{ND}$ as a function of P.d has a similar tendency. The laser output energy $E_{out}$ decreases with input pulse duration $t_p$ increasing, and the rrore the value of $t_p$ increases, the higher that of V$V_{G.min}$ is obtained because the number of photons N decreases with $t_p$ increasing. In addition, the laser-guided de discharge range and the discharge guide characteristics as laser outpIt $E_{out}$ was investigated.igated.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.73-78
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• 2005

본 연구에서는 서울시 한강에 위치한 교량을 대상으로 다양한 조망점에 따른 경관조명의 물리량을 측정하고 그 특성을 분석함으로써 동일한 연구대상에 대하여 조망점이 달라졌을 때 나타나는 물리적 변화를 통해 경관조명분야의 물리량평가방법론의 새로운 접근방법론을 제시하는 것이 목적이다. 이를 위하여 연구대상의 선정은 교량구조형식에 따라 분류하고. 경관조명이 설치된 교량 17개소 중 다양한 조망점과 현장측정의 편리성 등을 고려하여 광진교(거더교), 올림픽대교(사장교), 동작대교(트러스교), 동작대교(아치교)를 연구대상으로 선정하였다. 조망점은 한강둔치를 이용하는 방문객들이 바라보는 투시뷰, 교량주변 건축물에서 바라보는 건물뷰 그리고 교량 위를 이동하면서 바라보는 주행뷰로 구분하였다. 이러한 연구방법으로 도출된 결과는 동일한 경관조명연출을 토대로 교량별 조망점에 따른 휘도측정 및 분석에서 측정되는 각도, 거리, 방향에 따라 정형화된 비율은 아니지만 휘도값에 있어서 차이가 있다는 것을 확인 할 수 있었으며, 투시뷰와 건물뷰는 동일한 교량 구성요소를 갖고 있어 상호간 비교 분석이 가능하고 경관조명평가 요소로서 그 기능을 담당 할 수 있다고 판단되며, 주행뷰는 교량형식과 가로등의 영향을 많이 받으므로 평가요소로써 조망점을 활용하기에는 조금 더 깊은 연구가 선행되어야 할 것으로 보인다. 따라서 경관조명을 평가함에 있어 다양하게 바라보는 조망점은 조명연출로 인한 시각적 인식에 차이를 유발시킬 수 있어 경관조명을 평가할 때 다양한 조망점의 설정이 보다 객관적이고 정확한 분석이 가능할 것으로 판단된다.ridinium의 분포는 chlorophyll-a농도와 밀접한 관련성이 있었다. 담수적조의 현존량은 상류지역에서 $8.5\;{\times}\;10^3\;cell\;mL^L{-1}$로서 많았고, 댐부근의 하류지역($4.4\;{\times}\;10^2\;cell\;mL^L{-1}$)으로 갈수록 감소하는 양상을 보였다. 또한, 담수적조의 원인종으로 규조류 Synedra acus와 남조류 Microcystis aeruginosa도 소량관찰되었다. 저수지의 수질 부영양화 현상은 기존 경사사면형 농경지를 기반으로 조성되었으므로 저층으로부터 풍부한 영양환경을 내재하고 있었고, 담수 초기에 발생할 수 있는 가능성을 포함하고 있었다. 또한 유입수량의 부족과 현재 수질개선을 위해 적용하고 있는 수중폭기시설등의 물리적인 영향도 직 ${\cdot}$ 간접적으로 작용하였을 것으로 추정되었다 따라서 향후 이에 대한 중장기적인 모니터링이 필요하였고 유역과 저수지의 통합적인 수질관리계획 이 요구되었다.group으로, 용존산소량, 전기전도도, pH, 인산염이 정점 3, 4, 5에서 같은 group으로 묶였다.유의적인 CAT 활성 증가효과가 나타났고, 간조직의 시토졸 1획분에서는 대조군 대비 15${\sim}$27%의 CAT 활성 증가효과가 인정되었다. 이상의 결과에서 목초액의 장기간 투여는 간조직 중의 활성산소의 억제효과뿐만 아니라 방어시스템으로서 활성산소 제거효소의 역할도 충실히 수행하여 노화를 효과적으로 예방하고 억제할 수 있을 것으로 기

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.259-262
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• 2005

Ground resistance measurement is an elementary technique for the evaluation of grounding system. There are main environmental factors to consider for correct measurement but the problem is that it is practically most cases to measure ground resistance unable to know the factors. This paper presents a methodology toward true value of resistance in the unknown circumstances, utilizing the defined term 'variation rate' of potential difference curve appearing in the distance to a current probe as in the three point fall-of-potential method which comprises the characteristics of environmental factors. This methodology is a induced result from the previous demostrated studies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1087-1096
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• 2011

Vehicular Ad Hoc Network(VANET) using wireless network is offering the communications between vehicle and vehicle(V2V) or vehicle and infrastructure(V2I). VANET is being actively researched from industry field and university because of the rapid developments of the industry and vehicular automation. Information, collected from VANET, of velocity, acceleration, condition of road and environments provides various services related with safe drive to the drivers, so security over network is the inevitable factor. For the secure message authentication, a number of authentication proposals have been proposed. Among of them, a scheme, proposed by Jung, applying database search algorithm, Bloom filter, to RAISE scheme, is efficient authentication algorithm in a dense space. However, k-anonymity used for obtaining the accurate vehicular identification in the paper has a weak point. Whenever requesting the righteous identification, all hash value of messages are calculated. For this reason, as the number of car increases, a amount of hash operation increases exponentially. Moreover the paper does not provide a complete key exchange algorithm while the hand-over operation. In this paper, we use a Received Signal Strength Indicator(RSSI) based velocity and distance estimation algorithm to localize the identification and provide the secure and efficient algorithm in which the problem of hand-over algorithm is corrected.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5766-5772
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• 2011

This study was to investigate the change of gait temporal parameter and ankle joint moment between patients with achilles tendinitis and healthy people. Thus, the purpose of this study is to clarify biomechanical change of gait in patients with achilles tendinitis and to find risk factor for prevention of achilles tendinitis. We recruited 20 patients with an achilles tendinitis and 20 healthy people. While subjects shuttled 5 times on 13 m distance with comfortable pace, we examined gait function marker with three-dimensional gait analysis system. All subject outstepped center of forceplate during gait and calculated ankle joint moment using software. Obtained data was analyzed using SPSS 12.0 software. In results, we confirmed that patients with achilles tendinitis showed reduction of extension moment in early initial phase and reduction of flexion moment in mid-stance on hip joint. and reduction of flexion moment in early initial phase and reduction of extension moment in late phase on knee joint. And we identified that patients with achilles tendinitis showed reduction of dorsiflexion moment in early stance phase, maximal plantarflexion moment in mid stance phase, and dorsiflexion moment in late stance phase. Thus, there are biomechanical changes on gait in patients with achilles tendinitis compared to healthy people. And, in clinical settings, they should focus on changes of gait in patients with achilles tendinitis. Further study will be undertaken for the biomechanical changes of patietns with achilles tendinitis.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.2
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• pp.46-53
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• 2003

In order to analyze the movement characteristics of suspended solid(SS) in harbor construction, we investigate the generation and movement processes of the SS for the landfill construction by direct casting method and the grab dredging construction which is the most frequent process in harbor construction. We find that the SS is generated into a very high concentration right after the direct casting of landfill soil and continued up to 60 minutes in the landfill construction using the direct casting method with dredged materials by a ship of 700-tonnage. In the grab dredging construction, the SS is generated in a high density of concentration near at its source regardless of water depth, formed belt and diffused up to 700m along the trajectory of tidal current. Based on the result of the present study, it is recommended for the mitigation of SS generation that the silt protector be deployed near at construction site close enough to block the diffusion of SS and the body length of silt protector be long enough to mitigate the SS diffusion in the bottom layer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.148-154
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• 2020

This study examines room assignments to improve accessibility in a university dormitory depending on the student grade, taking into account frequency of using a certain common space. An integer programming model is presented to minimize the total moving distance from the common space to the students' rooms for accessibility. The model also constrains the maximum capacity of a room, and disallows different grade students to be assigned to the same room. This model is similar to a facility location problem used widely in the supply chain management field. Applying our optimization model to a small group at the dormitory of Unversity A as the case study, our results indicate that lower grade students are assigned rooms closer to the common space due to their higher frequency of using that space to guarantee high accessibility. Moreover, if higher grade students are prioritized to select their rooms, we suggest an objective function that imposes a penalty in cases when lower grade students select rooms with priority. Based on the results obtained, we propose assigning rooms to students in a dormitory by considering their complex requirements and convenience to use the common space.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.49-54
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• 2006

The X-ray unit developed by this study is to diagnose emergency cases which is too far from a hospital and to classify the patients. We have to use the X-ray in a ambulance or the scene of an accident where we cannot use the AC220 outlet because of the distance from a hospital as well. The X-ray unit developed has a characteristics as follows. First of all, as the unit has a condenser in itself where there is no electric supply, we can use the X-ray inspector in a mountain area or a island. Second, we can detect by digital detector the information taken by X-ray from DC 12[V] electricity and store as a form of file. A control circuit can secure the reliability of the X-ray unit by using the Pic16F84A X-ray and provide various functions. The X-ray unit which suits remote emergency system can be efficiently used for the emergent cases who is too far from a doctor and a hospital or in the situation where it is difficult to diagnose, transcribe and treat simultaneously.