• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.84-96
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• 2013

Recently, architectural design has been changing from formal design to freeform design due to the digitalization of construction industry. Especially, the formal design has been accepted as a design trend recently and applied many times as a design concept in the architectural design competitions such as turn-key. However, various deflects such as water leak and cracks have been occurred because the traditional construction methods had been applied without any revision or adaptation of the formal construction method for the freeform building construction. Design and construction of freeform building has been developed as an new method in order to solve the problems and minimize the construction duration and cost for the freeform building. Therefore this research deduced the positive implications for developing freefrom envelope by analyzing the domestic and abroad cases and proposed the considerations during design and construction of the freeform envelope as follows. First, the freeform design should consider the constructability for the freeform envelope. Second, manufacturing technology for the two-way curvature of the unit panel should be developed. Third, exposed concrete form method should be developed for the freeform envelope of concrete. Forth, material characteristics, construction method and facility management should be considered in order to manage precipitation and keep water-proof according to the classification of the freeform envelope area.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2206-2217
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• 1971

Spillway and discharge channel of reservoirs require the Control of Large volume of water under high pressure. The energies at the downstream end of spillway or discharge channel are tremendous. Therefore, Some means of expending the energy of the high-velocity flow is required to prevent scour of the riverbed, minimize erosion, and prevent undermining structures or dam it self. This may be accomplished by Constructing an energy dissipator at the downstream end of spillway or discharge channel disigned to dissipated the excessive energy and establish safe flow Condition in the outlet channel. There are many types of energy dissipators, stilling basins are the most familar energy dissipator. In the stilling basin, most energies are dissipated by hydraulic jump. stilling basins have some length to cover hydraulic jump length. So stilling basins require much concrete works and high construction cost. Flip bucket type energy dissipators require less construction cost. If the streambed is composed of firm rock and it is certain that the scour will not progress upstream to the extent that the safety of the structure might be endangered, flip backet type energy dissipators are the most recommendable one. Following items are tested and studied with bucket radius, $R=7h_2$,(medium of $4h_2{\geqq}R{\geqq}10h_2$). 1. Allowable upstream channel slop of bucket. 2. Adequate bucket lip angle for good performance of flip bucket. Also followings are reviwed. 1. Scour by jet flow. 2. Negative pressure distribution and air movement below nappe flow. From the test and study, following results were obtained. 1. Upstream channel slope of bucket (S=H/L) should be 0.25<H/L<0.75 for good performance of flip bucket. 2. Adequated lip angle $30^{\circ}{\sim}40^{\circ}$ are more reliable than $20^{\circ}{\sim}30^{\circ}$ for the safety of structures.

• Journal of IKEEE
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• v.23 no.4
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• pp.1461-1464
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• 2019

In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.5
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• pp.219-224
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• 2015

In this paper, the designed fish robots DOMI ver1.0 is researched and development for aquarium underwater robot. The presented fish robot consists of the head, 1'st stage body, 2nd stage body and tail, which is connected two point driving joints. The model of the robot fish is analysis to maximize the momentum of the robot fish and the body of the robot is designed through the analysis of the biological fish swimming. Also, Lighthill was applied to the kinematics analysis of robot fish swimming algorithms, we are applied to the approximate method of the streamer model that utilizes techniques mimic the biological fish. The swimming robot has two operating mode such as manual and autonomous operation modes. In manual mode the fish robot is operated to using the RF transceiver, and in autonomous mode the robot is controlled by microprocessor board that is consist PSD sensor for the object recognition and avoidance. In order to the submerged and emerged, the robot has the bladder device in a head portion. The robot gravity center weight is transferred to a one-axis sliding and it is possible to the submerged and emerged of DOMI robot by the breath unit. It was verified by the performance test of this design robot DOMI ver1.0. It was confirmed that excellent performance, such as driving force, durability and water resistance through the underwater field test.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.891-894
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• 2008

This study was performed to investigate how to design, where to construct, why to degrade, what plan to use systematically the underground structures such as underpass, underground passageways. About 50% of the underground structures are located on Seoul, Kyungi-Do. In design of the underground structures such as underpass, underground passageways, the required conditions are defined. And also in construction stage, the conditions of soil, required structure depth, site characteristics, reasonable construction method, are investigated. In the selection of details for underground structure, the items mainly considered, are the wall and column type, the sidewalk type, anchoring-system type, the water-proofing method, entranc shape. The reason and the adequate measures for the degradation of concrete structure are also investigated. The initial cracking properties due to the thermal characteristic are considered. The state of the art report on the new technologies are reviewed. The recent project for the systematically application to the underground structures is reviewed.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.85-85
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• 2011

홍수기에 안전하고 정확한 유량측정을 통하여 물관리에 필요한 기초수문자료를 확보하고자 한국수자원공사에서 1993년도부터 홍수유량측정기술 확보를 위한 연구를 시작하였다. 그간의 연구성과를 바탕으로 1999년도에 하천의 유속을 비접촉식으로 측정할 수 있는 홍수용 전자파표면유속계를 개발하여 특허등록하였고 그와 동시에 이의 상품화를 추진하여 2010년도까지 75대를 보급하여 실무에서 이용하고 있다. 이동식인 홍수용 전자파표면유속계를 바탕으로 2001년도에는 고정식 실시간 홍수유량측정측정시스템을 개발하여 특허등록하였고, 이 시제품을 현재 용담 수자원시험유역의 동향지점에서 시험운영하고 있다. 또한, 현장 유량측정실무자들의 홍수용 전자파표면유속계 개선요구에 따라 편각용 전자파표면유속계 시제품을 개발하였으며, 이는 임의의 한 지점에 설치한 한 대의 장비로 좌우 여러 측선의 유속을 동시에 측정할 수 있는 다점 측정기능을 갖도록 성능을 개선하였다. 이에 따라 홍수시 유량측정에 소요되는 시간이 줄어들어 신속하게 유량측정을 완료할 수 있는 계기를 마련하였다. 이와 더불어 유속측정 범위를 확장하여 홍수시의 고유속 뿐만 아니라 0.5 m/s 이하의 저유속까지 측정할 수 있는 범용 전자파표면유속계의 시제품을 추가로 개발하였다. 이 장비는 최저유속 0.03 m/s의 측정을 실내시험을 통하여 입증하였다. 범용 전자파표면유속계는 상품화 시제품의 개발을 목표로 기존 시제품의 현장시험을 통하여 현장적용상의 문제점에 대한 해결에 주력하였다. 첫째, 평갈수용 전자파표면유속계의 사용편의를 개선하기 위하여 소형화 및 경량화를 추진하였고, 이를 위하여 사용주파수를 기존의 10 GHz에서 24 GHz로 변경함으로써 $35{\times}35\;cm$ 크기의 기존안테나를 $22{\times}22\;cm$ 크기로 소형화하였으며 송수신부의 무게는 기존 18 kg에서 3.3 kg으로 혁신적으로 줄이는데 성공하였다. 이를 위하여 안테나는 기존의 반사형안테나에서 도파관슬롯배열안테나로 변경하였다. 둘째, 측정값의 안정화를 위하여 안테나의 특성을 개선하여 부엽(side-lobe) 레벨 30 dB 이하 그리고 전후방비(front-back ratio) 50 dB 이하로 개선하여 안테나가 지향하는 방향 이외의 위치에서 반사되는 불필요한 신호를 줄였다. 또한 적응형 이득제어(adaptive gain control)기법의 채택으로 미소 신호에 대한 안정적 측정 및 과다 신호에 대한 능동적 감쇄를 할 수 있도록 시스템을 구성하여 전 유속범위에 대한 안정적 측정을 가능토록 설계 및 제작하였다. 셋째, 자가점검 기능을 탑재하여 유속측정 전에 기기의 상태에 대한 self test기능을 통하여 측정자가 기기의 상태를 사전에 파악 가능토록함으로써, 기기 오작동에 대한 능동 대처할 수 있도록 하였다. 이외에도 저전력 회로설계를 통하여 배터리 사용시간을 확장하였고, 기존의 전자파표면유속계가 가지고 있던 방습 및 방수에도 내성을 갖는 제품으로 설계하였으며 스마트기기를 이용한 무선측정 및 세련된 디자인 등 사용자의 요구사항을 충분히 반영하였다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.197-201
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• 2008

Conceptual cost estimates for domestic highway projects have generally been conducted using governmental unit-price references. Inaccuracies in governmental unit-price data has repeatedly addressed in the Korean construction industry which often lead to poor decision making and cost management practices. Thus, needs for developing a better way of conceptual cost estimating has been widely recognized. This research is considered as the first step in developing such model using real-world cost data based on actual construction activities. The data analyzed in this paper includes 41 P.S.C (Prestressed Concrete) Box bridges which broke into 4 categories based on construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). Actual design documents; including actual cost estimating documents, drawings and specifications were carefully reviewed to effectively break down cost structures for PSC girder bridges. Among more than 40 cost categories for each P.S.C girder bridge type, 7 of them were identified which accounted for more than 95% of total construction cost (ILM: 99.47%, MSS: 99.22%, FSM: 98.18%, and FCM: 98.12%). In order to validate the clustering of cost categories, the variation of each cost category has been investigated which resulted in between -1.16 % and 0.59%.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1528-1532
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• 2009

최근의 기상변화에 의한 이상 홍수와 유역의 도시화로 인한 불투수면적의 증가로 홍수시 유출량을 증가시켜 기존 하도의 적정소통량을 초과하는 홍수를 발생시키고 있다. 토지의 고도이용으로 하도의 하폭이 제한된 도시유역 초과 홍수에 대비할 수 있는 구조적 홍수관리방안은 제방 증고, 하천준설 등의 하천개수나 저류지 설치, 방수로 설치 등이 대표적이다. 주요 재해저감시설인 저류지는 개발사업에 의해 발생하는 증가된 유출량을 조절하는 개념으로서 도시홍수 재해경감의 목적으로 활용하기에는 설계기준 및 기술상의 이견이 최근 많이 제시되고 있다. 개발사업으로 인한 하류부의 영향에 대해 해당 사업지구에 국한하여 개발전의 유출량이하로 유지함을 목표로 하고 있으나 전체 유역차원의 검토는 이루어지지 않고 있어 저감효과가 의문시 되고 있다. 또한, 하류부 인근의 개발사업시행으로 저류지를 설치할 경우 사업대상지구의 홍수도달시간 변화가 발생하며, 전체 유역 첨두유량 발생시간과의 중첩현상으로 오히려 저류지 설치로 인해 본류 하천의 피해를 초래할 여지가 있다. 저류지 설치 위치에 따라 경제적, 치수적 효과가 달라진다는 점은 많은 연구의 결과로 알려져 왔다. 본 연구에서는 실제사업지구의 기존 재해영향 평가에서 저류지 설치에 의한 하류부 홍수량 증감에 대한 분석을 수행하고 저류지 면적 대비 전체유역면적 비율에 대하여 저류지 설치로 인한 홍수량 증감분석을 수행하였다. 홍수량 증감율은 저류지 설치에 따른 저감후 대비 저류지 설치전 본류하천 유역면적비가 31.17 이상인 경우, 저류지 설치에 따른 홍수량 저감후 대비 개발전 본류 하천 유역면적비가 27.05 이상인 경우에 홍수량이 증가하였다. 본 연구결과를 바탕으로 사업지구내 일률적인 저류지 설치계획보다는 추후 체계적인 저류지 계획을 위한 가이드라인 제시를 통해 합리적인 계획을 수립하여야 할 것으로 판단된다.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.288-298
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• 2000

Digital assets denote multimedia information that exists in the form of digitized materials such as images, audio, and video. The management of digital assets demands much effort because of a huge amount of storage space requirement and multidimensional characteristics of the information needed to describe their contents. In this paper, we design and implement a Digital Asset Manager that stores and manages digital assets efficiently. Among the various types of digital assets, we focus on the video asset which has the highest complexity. Our Digital Asset Manager provides various facilities for digital contents authoring applications. In the Digital Asset Manager, video assets are managed by using a hierarchical model in order to ensure efficient accesses to any part of a video asset. Our system also guarantees the independence from the storage platform, and provides a fast content-based similarity search method on the digital assets.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.155-165
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• 2013

Recently, geotextile tube method can be widely applied to the river, costal and marine in the construction field, such as embankment, groin, breakwater, dyke structures and so on, in advanced countries of the world. And that has been constructed at the temporary road for incheon, ilsan-bridge construction and coast erosion protection in republic of korea. Geotextile tube is a tube shaped geotextile product and hydraulic pumping filled with dredged soils. In this paper, the numerical analysis was performed to investigate the behavior of geotextile tube with various properties of material character, shape condition, construction pressure and so on. Also, the field test was conducted in order to identify the construction ability of Samangum waterproof embankment using geotextile tube. According to the applied of field test, geotextile tube was 65 m long and 4.0 m diameter. Also, the permeability coefficient and ultimate tensile strength of geotextile tube is $1.6{\times}10^{-1}$ cm/sec and 205.26 kN/m, respectively. As a result of filed test, when filled, geotextile tube does not attain the same as its unfilled theoretical diameter, but may reach approximately of 55 percent of the theoretical diameter. At the time, geotextile tubes were 12.56 m in circumference and filled to a height of about 2.2 m. This paper presents case study on field application and behavior analysis of the saemangum waterproof embankment donggin 1 division construction using geotextile tube.