• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.773-776
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• 2008

The corrosion of steel in concrete is significant in marine environment. Marine bridges are readily deteriorated due to the exposure to marine environment. Salt damage is one of the most detrimental causes to concrete bridges and port structures. Especially, the splash and tidal zones around water line are comparatively important in terms of safety and life-time point of view. During the last several decades, cathodic protection (cp) has been commonly accepted as an effective technique for corrosion control in concrete structures. Zn-mesh sacrificial anode has been recently developed and started to apply to the bridge column cp in marine condition. The detailed parameters regarding Zn-mesh cp technique, however, have not well understood. This study is to investigate how much Zn-mesh cp influences along the concrete column at elevated temperature. About 100cm column specimens with eight of 10cm segment rebars have been used to measure the variation of cp potential with the distance from Zn-mesh anode at both 10$^{\circ}$C and 40$^{\circ}$C in natural seawater. The cp potential change and current diminishment along the column specimens have been discussed for the optimum design of cp by Zn-mesh sacrificial anode

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1856-1864
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• 2015

In this paper, the localization algorithm for improving the accuracy of the positioning using the Wi-Fi fingerprint using the normal distribution probability and the built-in typed accelerometer sensor, the gyroscope sensor of smartphone in the indoor environment is proposed. The experiments for analyzing the performance of the proposed algorithm were carried out at the region of the horizontal and vertical 20m * 10m in the engineering school building of our university, and the performance of the proposed algorithm is compared with the fingerprint and the DR (dead reckoning) while user is moving according to the assigned region. As a result, the maximum error distance in the proposed algorithm was decreased to 2cm and 36cm compared with two algorithms, respectively. In addition to this, the maximum error distance was also less than compared with two algorithms as 16.64cm and 36.25cm, respectively. It can be seen that the fingerprint map searching time of the proposed algorithm was also reduced to 0.15 seconds compared with two algorithms.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.182-188
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• 2008

The MLC(multi leaf collimator) in charge of important role in radiation therapy field recently have been exchanging from shielding block into it rapidly, owing to being convenient. However, MLC can be occurred the leakage dose of inter_leaves and the error of algorithm in imput and output from digital signal. We compared the difference of imput method to MLC made by Varian Cop. with the error and effective field induced by MLC shaper and film scanner based on XimaVision value as using MLC layer of various shapes. According to comparing standard value with them to basic MLC layer (test1-5), MLC shaper was $0{\sim}0.29cm$, $0.23{\sim}3.59cm^2$ and film scanner was $0{\sim}0.78cm$, $0.24{\sim}3.89cm^2$. At the MLC layer to be applied in clinic, MLC shaper was $0{\sim}0.54cm$, $0.04{\sim}1.68cm^2$ and film scanner was $0{\sim}0.78cm$, $0.24{\sim}3.89cm^2$. The more distance and field from axis of central line increase, the more bigger the error value increases. There is a few mm error from standard point at the process which imput various information to apply MLC in clinic. and effective field did not have variation of monitor unit and dose owing to being a few cm2 error against real field. But there are some problem to shield critical organs because some part of target volume induced by the movement of organs can be not included, therefore we have to pay attention on the process to imput MLC layer

• Korean Journal of Construction Engineering and Management
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• v.20 no.3
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• pp.22-30
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• 2019

The purpose of this study is to derive basic data of the Guaranteed Maximum Price(GMP) process and to present specimens that can be used at the time of execution of CM at Risk project in South Korea. CM at Risk project is issued in South Korea, but the actual data is lack. On the other hand, CM at Risk project is universalized and the market of the CM at Risk is steadily growing. Because of that, in this study, The United States cases was selected as a sample. GMP consists of CM's fee, CM contingency, project direct cost, project indirect cost, allowance. GMP negotiations are performed before the end of design completion, and after 3 rounds of estimation comparison, preliminary GMP is confirmed. GMP can be multiple contract and it is useful for Procurement of long lead materials and early construction. If the actual cost is lower than expected GMP, sharing of the saving is an option since the conflict of interests between the client and the contractor can occur.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.619-626
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• 2012

One-way Network-RTK(Real Time Kinematics) is considered as a method which can satisfy moving vehicle's recently-required high accuracy and mobility. When we use one-way Network RTK for vehicle navigation, multiple cells-based system is required to provide the service continuously in wide area. The rover which moves through various cells inevitably experiences a correction discontinuity, which is not eliminated by the DD(Double Difference) method and to cause 13cm(horizontal) and 48cm(vertical) position error. We suggest three solutions to reduce this discontinuity, which are identification of master RS with neighbor networks, duplication of communication module to receive corrections from other cells, and ambiguity adjustment between neighbor cells. All of our suggestions reduce the error to 1/4 wavelength in measurement and 3cm in position-domain, and we suggest the ambiguity adjustment is the best when we consider the extendibility of service area and the cost of rover device.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.298-299
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• 2018

The construction liability type CM has been introduced in the form of a pilot project through public institutions since 2017 since it was introduced in the term of construction responsibility type construction project management in the Basic Law of Construction Industry in 2011 with the aim of improving the constitution of the Korean construction industry and strengthening global competitiveness. Through the introduction of construction-responsible CM, the government intends to change the paradigm of the overall construction industry, including design and construction, construction costs, disputes between stakeholders, and transparency of business. In this regard, the study aims to compare and analyze the evaluation methods on the bidding guide that public institutions (LH) are currently using to select companies in order to lay the foundations for successful construction of construction-responsible CM ordering methods.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.27-31
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• 2003

최근 해외시장에서는 Single Point Responsibility 개념의 선호와 프로세스사업관리능력의 중요성으로 건설사업관리 (Construction Management: 이하 CM)방식이 프로젝트 조달의 중요한 방안으로 사용되며 국내에서도 최근 CM 발주량의 획기적인 증가추세로 사업수행능력 향상을 위한 도구 개발이 절실하다. 가장 유용한 도구로는 국내${\cdot}$외 CM 수행사례 분석을 통해 이에 저해되는 요인과 모범사례 등을 파악하여 산업계로 하여금 체계적 점검과 벤치마킹을 통해 수행능력을 제고할 수 있는 핵심성공요인과 Best Practice의 보급 발간이다. 따라서 본 논문은 최근 감사원에 의해 모범선행사례로 선정된 무주 하천 1,2급 수해복구 건설사업관리 용역에 대한 CM성과를 분석하여 핵심성공요인과 Best Practice를 제공하는 것을 주요 목표로 한다. 본 CM용역에서는 무엇보다도 무주군내 수해복구공사에 CM 사업방식을 도입한 것은 현명하고 진취적이며 시기 적절한 일이라고 판단되며 이러한 선도적 기자체의 의욕적인 시도가 지방에서 수행되는 공공공사의 수준을 한 차원 높이는 계기가 됨은 물론 항구적인 복구공사기법의 하나로 정착하기를 기대한다. 또한 산업계는 CM관련 중심기관을 통하여 이러한 모범사례의 연속적인 분석과 보급을 통해 산업계 전반적인 CM수준을, 제고하여 국내외 CM확대 적용의 기반을 조속히 조성할 수 있기를 바란다.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.190-197
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• 1997

This study was conducted to determine the optimum hydroponic system and nutrient solution for promoting the growth and flowering of hydroponically grown carnation. DFT (deep flow technique) and NFT (nutrient film technique) systems were employed and four kinds of nutrient solution, which are Cooper solution, Yamasaki solution, balanced nutrient solution by Japanese Horticultural Experiment Station and PTG solution in the Netherlands were used and compared. pH was lowest in the PTG solution compared to the other nutrient solutions used. Plant height was highest in the DFT system in the plot of PTG solution as of 53.0 cm at 88 days after transplanting, while lowest in NFT system with Cooper solution. Stem diameter was more thickened in NFT system with PTG solution as of 7.2 mm at 88 days after transplanting. Days to flowering was shortened to 122.3 days in NFT system when PTG solution was used. This results suggested a combination of NFT system with PTG solution as optimum hydroponic system and nutrient solution for cut carnation production. Further trials as to the management of nutrient solution by glowing stages should be followed.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.131-142
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• 2012

Since CM for Fee has been introduced in domestic market of construction industry, Construction Management(CM) has been familiar with one of the established delivery systems in Korea. However, CM(CM for Fee) construction market has been stagnant consistently due to recent economic recessions. The fundamental causes of the current depression of CM construction market are highly related to the social/environmental factors(such as owner's negative perception about CM services, exclusive formation of the CM markets, unfeasible fee and limitations on technology developments in CM services) and the shortage of institutions associated with CM. Accordingly, fundamental improvements on the CM environment are required. This study suggests the feasible methods for improvement on CM system based on fundamental analysis of problems related to the environmental factors by conducting a delphi technique with professional personnels on various positions in CM markets.

• The Journal of Korean Society for Radiation Therapy
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• v.13 no.1
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• pp.126-129
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• 2001

I. 목적 : Half beam을 이용하여 인접한 조사면 치료시, 경계부위에서 발생할 수 있는 Jaw Position에 의한 기하학적 오차는 정확한 선량전달에 문제를 일으킨다. 이에 본 저자는 QA용 필름을 이용하여 조사면 setting 방법과 조작자간의 오차를 분석하고 이를 최소화할 수 있는 방법을 찾고자 한다. II. 대상 및 방법 : 본 실험은 6MV선(CL2100C, Varian, USA)을 대상으로 하였으며, 폴리스틸렌팬톰($25{\times}25cm2$)을 SSD 100 cm으로 고정한 후, 측정용 필름(X-omat V2, Kodak, USA)을 5 cm 깊이에 위치 시켜 조사면의 중심에서 경계를 이루는 비대칭 조사면 ($0/7.5{\times}15,7.5/0{\times}15 cm$)을 쌍으로 조사하였다. 조사된 필름은 자동현상기를 이용하여 현상한 후 농도계(Densitometer, Multidata, USA)를 이용하여 중심축상에서의 농도분포를 측정하여 인접한 조사면에서의 오차를 분석하였다. 조작방법과 조작자간의 오차를 분석하기 위하여 5명의 방사선사를 대상으로 auto및 manual set-up을 실시하였고 각 방법의 평균 오차를 분석하기 위해 5회 반복하였다. III. 결과 : 필름 농도곡선을 이용하여 두 조사면이 만나는 경계에서의 오차를 분석한 결과, remote console set-up의 경우 주변 조사면에 비해 $-0.16{\pm}3.44\%$, pendant방식에서는 $+5.04{\pm}4.37\%$로 나타났고, 조작자간의 유의성이 관찰되었다. IV. 결론 : 비대칭 조사면을 이용한 근접 조사면의 치료시 pendant 방식보다 remote console 방식에서 오차가 적 게 나타나므로 Auto set-up 기능의 이용은 치료시에 조사면 경계에서의 선량 오차를 최소한으로 줄이는데 도움이 될 것으로 생각된다. 또한 manual 방식으로 set-up 시 오차의 편차가 크게 나타나므로 치료시에 세심한 주의가 필요할 것으로 사료된다.