• 산업공학
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• 제16권1호
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• pp.44-53
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• 2003

Ready-Mixed Concrete transportation business has been managed by the manual operation and intuitive decision making. This study is on the process improvement on ordering process, and allocation/transportation of trucks commuting between the batching plant and construction sites. Processes of order collection, job dispatch and allocation, and on-time-delivery are analysed and improved. The logistics control system, with GPS system, was developed and implemented based on the reconstructed processes. Performances are evaluated after improved business process and logistics system was applied, and it is shown that waiting time loss is decreased by 55%, and that efficiency is increased by 15%.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.430-440
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• 2009

Top-Base Foundation(TBF) was developed in Japan as a factory made concrete product. It is actively used in 6,000 sites by the end of 1980s in Japan and applied for a domestic patent in 1985. It is a shallow foundation whose effectiveness is proven by many relevant researchers and engineers. TBF was introduced to Korea in 1991 and has been applied mainly to architectural structures to date. Currently, the effectiveness in bearing capacity and settlement of TBF is being underestimated for civil engineering structures. Characteristics of Top-Base Foundation studied in Japan and Korea is known as follows: (1) as concrete part and crushed stone behave together, they perform the function of rigid mat; (2) the conical part and pile part of TBF disperses load by interaction with the crushed stone; (3) by preventing lateral strain and differential settlement on lower ground, it improves bearing capacity and constrains settlement at the same time. In Korea, it is used mostly in clayey soft grounds. The formula of bearing capacity and settlement of TBF suggested in Japan give the values of the underestimated. bearing capacity while its settlement is overestimated in comparison with the values measured from the field loading test. Therefore, in this study, the stress delivery mechanism of Top-Base Foundation developed in Japan and Floating Top Base developed in Korea is investigated through numerical analysis and laboratory model test.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.69-74
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• 1995

The primary purpose of this study is to investigate reusal techniques of fly ash of combined heat power plant in the construction field, which may contribute to the saving of construction materials and conservating environment. Firstly chemical and physical characteristics of fly ash is analysed. And then, the usability of the concrete is tested by investigating the flowablility and stength development through parameters of various replacement ratios with respect to different mixing conditions. Finally, the durability and mechanical properties(elastic modulus) of the concrete is tested. As the result of the study, the following conclusions are derived : (1) the quantity of the CaO in the fly ash is relatively high based on the chemical analysis, (2)the compressive strength ratio of the mortar is satisfied with the specification, but the unit water ratio increased, (3)high strength concrete of more than 400kg/$\textrm{cm}^2$ can be developed in the ranges of FA 30%, W/B 40%, (5)the slump loss with the elapsed time due to the delivery is decreased as the replacement ratio of the fly ash is increased, (6)the modulus of the elasticity is matched withn the specification of the Architectural Institute of Korea.

• Smart Structures and Systems
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• 제18권3호
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• pp.601-623
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• 2016

Precast concrete elements are widely used in the construction of buildings and civil infrastructures as they provide higher construction quality and requires less construction time. However, any abnormalities in precast concrete surfaces such as non-flatness or distortion, can influence the erection of the elements as well as the functional performance of the connections between elements. Thus, it is important to undertake surface flatness and distortion inspection (SFDI) on precast concrete elements before their delivery to the construction sites. The traditional methods of SFDI which are conducted manually or by contact-type devices are, however, time-consuming, labor-intensive and error-prone. To tackle these problems, this study proposes techniques for SFDI of precast concrete elements using laser scanning technology. The proposed techniques estimate the $F_F$ number to evaluate the surface flatness, and estimate three different measurements, warping, bowing, and differential elevation between adjacent elements, to evaluate the surface distortion. The proposed techniques were validated by experiments on four small scale test specimens manufactured by a 3D printer. The measured surface flatness and distortion from the laser scanned data were compared to the actual ones, which were obtained from the designed surface geometries of the specimens. The validation experiments show that the proposed techniques can evaluate the surface flatness and distortion effectively and accurately. Furthermore, scanning experiments on two actual precast concrete bridge deck panels were conducted and the proposed techniques were successfully applied to the scanned data of the panels.

• 한국구조물진단유지관리공학회 논문집
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• 제14권6호
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• pp.198-204
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• 2010

콘크리트 믹서트럭의 덮개는 레미콘 플랜트에서 공사 현장까지의 운반 도중 굳지 않은 콘크리트의 유동성이 저하하지 않도록 사용하는데, 설문 결과 일반시민들에게 더러운 이미지를 주고 있다. 이러한 이미지로 인해 건설 산업 전체의 이미지에도 영향을 미칠 것으로 예상하여 덮개의 효용성 여부를 밝히기 위해 레미콘을 현장에 대기시켜 둔 채 유동성을 비롯한 공기량, 콘크리트 온도변화 등의 현장 실험을 실시하였다. 또한 이와 비교를 위해 동일한 조건으로 실내 실험을 병행하여 결과를 도출하였다. 실험 결과, 믹서트럭의 덮개는 슬럼프 저하에 미치는 영향이 적은 것으로 나타났다. 공기량 변화는 덮개 유무에 관계없이 60분까지는 적정한 수준으로 품질에 큰 영향을 미치지 않는 것으로 나타났다. 또한 콘크리트 압축강도는 덮개 유무에 관계없이 90분까지의 시료의 경우에 목표설계기준강도에 모두 적합한 것으로 나타났다.

• Smart Structures and Systems
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• 제21권2호
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• pp.139-149
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• 2018

Understanding the current status of a construction project is necessary to achieve successful on-site management. Real-time information delivery is a major concern for construction industry practitioners in order to expedite decisions and discussions. We propose the use of a first personal view (FPV) system of a quadcopter drone as a tool for monitoring on-site status and communicating between construction participants. The most important function of the drone FPV system is its ability to visually monitor construction site situations in real time. An on-site management system process is developed, verified, and applied to several construction work tasks after determining factors that affect efficient construction management. The proposed system is expected to assist the construction manager in achieving high efficiency.

• 무역상무연구
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• 제12권
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• pp.133-162
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• 1999

The international sale transaction is in essence a sale of goods and presents all those commercial and legal problems in any sale of goods. As a result, A International sales contract imposes several duties on the parties : the seller must deliver the goods and transfer ownership in them, while the buyer must pay the price and take delivery of the goods. However, there are several problems which impede a active transaction between seller and buyer who have their places of business in other countries each other. Therefore, It is necessary to provide the concept on the conformity of goods in the Int'l Sale of Goods. Especially, In our consideration for the point of time when defects occurs, the existence of non-conformity of goods should be judged on the basis of time of delivery rather than time of contract. Moreover, The burden of proof about nonconformity of goods is another fact which make an international dispute between the contractual parties in an international trade. Thus, The consistency in the interpretation of law must be maintained betweened the warranty and seller's liability. In the Uniform Commercial Code and UN Convention, non-conformity of contract is made of contract liability. And in our civil and commercial law provisions of warranty should be understand as the special ones of the provisions of general non-performance of obligation liability. As a result, More concrete study of them is required because they may have a great influence especially on international trade. As a result, We should be our best in finding a helpful and systematic structure that the dualistic structure of nonperformance of obligation liability and warranty liability must be unified by studying the theories of English and American warranty and our legal system, as well as international practice and usage being used in an international trade.

• 한국경영과학회지
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• 제21권3호
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• pp.127-141
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• 1996

In this paper, we propose a 7-phase life cycle model which applies to Computer Integrated Manufacturing systems. The model emphasizes product design and manufacturing design activities of CIM to secure the critical success factors of CIM systems such as high quality, adaptability, productivity, and flexibility. It is argued that the product design aspect would be divided into three phases-conceptual design, embodiment design, and detialed design. The conceptual design phase is to build a conceptual model of the product based on requirements and specifications which reflect "the voice of the customer". THe embodiment design phase utilizes specific design tools such as DFM, CAE, and CAD, and results in a concrete model of the product and parts. The detailed design phase is to crete a working prototype of the product and design tools such as DFA. CAD and CAM are employed in this phase. The output of the product design activity is to be the input for the manufacturing design activity. Using the proposed model, one can effectively and efficiently manufacture a high-quality, low-cost product with short delivery time, and above all achieve customer'ssatisfaction.isfaction.

• 한국콘텐츠학회논문지
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• 제10권7호
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• pp.88-97
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• 2010

최근 유비쿼터스 기술의 발달과 도시의 패러다임 변화에 따라 효율적인 광고의 정보 전달을 위하여 첨단 기술과 매체간 융합을 통해 버스의 도착시간안내, 스마트폰을 활용한 광고 등 도시민들에게 더욱더 편리한 서비스를 제공하고 있다. 그러나 뉴미디어를 이용한 실시간 이동형광고의 경우 대용량 데이터의 전달방법과 통신료 부담 등의 어려움이 많아 이를 개선시키는 방법이 필요하다. 본 논문은 이러한 어려움을 극복하고자 연구 되었다. 이동형광고 중 u-버스광고 비즈니스 모델과 이동시 실시간 정보제공, 대용량 데이터전송 등 매체의 특성 분석을 통한 차별화 사업전략 방안을 제시하며, 운영센타에서 네트워크를 통해 차량 단말부를 통한 광고송출까지 구체적인 시스템 구축방안을 제시한다. 본 논문은 첨단기술과 다양한 매체와의 융합을 통한 실무적으로 활용 가능한 비즈니스모델로서 시사점을 제공한다는 측면에서 큰 의의가 있다.

• 한국통신학회논문지
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• 제37권4B호
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• pp.219-226
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• 2012

무선 센서 네트워크에서 위치기반 멀티캐스트 라우팅은 중복되어 전송되는 메시지 전송 횟수를 줄임으로써 무선 센서 네트워크망의 채널 용량과 수명을 증가시킬 수 있다. 하지만 기존의 위치기반 멀티캐스트 알고리즘들은 센서 노드의 위치만을 고려하여 패킷을 전송하기 때문에 장애물이나 다른 무선기기의 간섭영향이 존재하는 실제환경에서는 네트워크 성능이 저하될 수 있다. 이를 해결하기 위하여 본 논문에서는 간섭의 영향을 고려한 위치기반 멀티캐스트 알고리즘을 제안한다. 제안한 알고리즘에서 각 센서 노드는 간섭영향을 고려하여 각 링크에 패킷전송 시 소모되는 에너지를 계산하고 이를 바탕으로 간섭영향이 가장 적은 링크를 통해 멀티캐스트 패킷을 전송한다. 시뮬레이션 결과, 제안한 알고리즘은 기존 연구들에 비하여 패킷전송률과 에너지 소비 측면에서 향상된 성능을 보였다.