• 대한교통학회지
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• 제28권4호
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• pp.177-186
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• 2010

본 논문의 주요 목적은 도로디자인에 관련한 지침, 즉 고속도로 진 출입구간에서 도로중앙에 위치한 다인승전용차로 진 출입구간까지의 거리에 대한 지침을 마련하는 것이다. 다인승전용차로는 일반적으로 고속도로 중앙에 위치하고, 고속도로차로를 가로질러 위빙(weaving)하여 진입할 수 있다. 위빙구간에서의 많은 차로변경은 교통용량(capacity)에 심각한 영향을 끼친다. 위빙구간에서 이러한 차로변경의 영향을 분석하기 위해서는 간격수락이론이 유용하게 이용될 수 있다. 본 논문은 간격수락이론을 이용하여 산출된 차량의 상충의 정도를 기초로 하여 교통용량을 산출한다. 차량의 상충 정도는 주어진 위빙거리에서 차량의 위빙에 대한 성공 확률의 함수로 표현된다. 간격수락이론에 기초하여 위빙거리에 대한 지침을 마련함에 있어서, 이 논문은 위빙거리의 증가가 교통용량의 증가를 유발하지 않는 점을 위빙에 최소로 요구되는 거리로 정한다.

• Steel and Composite Structures
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• 제26권6호
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• pp.793-808
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• 2018

In this study, the seismic performance of the connections between L-shaped columns composed of concrete-filled steel tubes (L-CFST columns) and H-beams used in high-rise steel frame structures was investigated. Seven full-scale specimens were tested under quasi-static cyclic loading. The variables studied in the tests included the joint type, the axial compression ratio, the presence of concrete, the width-to-thickness ratio and the internal extension length of the side plates. The hysteretic response, strength degradation, stiffness degradation, ductility, plastic rotation capacity, energy dissipation capacity and the strain distribution were evaluated at different load cycles. The test results indicated that both the corner and exterior joint specimens failed due to local buckling and crack within the beam flange adjacent to the end of the side plates. However, the failure modes of the interior joint specimens primarily included local buckling and crack at the end plates and curved corners of the beam flange. A design method was proposed for the flexural capacity of the end plate connection in the interior joint. Good agreement was observed between the theoretical and test results of both the yield and ultimate flexural capacity of the end plate connection.

• 한국지반공학회논문집
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• 제35권6호
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• pp.27-38
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• 2019

균질한 지반에서 말뚝의 지지력은 선단지지력과 주변마찰력의 합이며, 사질지반에서는 주변마찰력이 선단지지력보다 우세한 것으로 알려져 있다. 다수의 말뚝을 근접하여 설치하는 무리말뚝에서는 말뚝 하나하나의 지지력이 말뚝 상호간 간섭에 의해 달라질 수 있으므로, 말뚝의 근접도에 따라서 선단지지거동과 주변마찰거동의 변화를 정확하게 파악하여 말뚝을 설계해야 한다. 따라서 본 연구에서는 주면마찰거동의 영향을 배제한 상태에서 무리말뚝의 선단지지거동을 측정하기 위해 크기가 일정한 원형 토조에서 여러 가지 직경과 깊이로 말뚝을 설치하고 상대밀도가 균일한 모래지반을 조성한 후 선단지지력을 측정하여 무리말뚝의 근접도에 따른 영향을 확인하였다. 연구결과 말뚝의 선단저항력은 비교적 뚜렷하게 극한값을 나타냈다. 말뚝의 극한선단지지력은 주면마찰력과 말뚝의 직경에 의한 영향을 적게 받으며, 말뚝관입길이가 깊어질수록 일정한 값에 수렴하였다. 또한, 무리말뚝에서 인접한 말뚝이 말뚝 직경만큼 서로 이격되어 있으면 인접말뚝의 영향이 거의 없었다.

• 한국축산식품학회지
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• 제41권4호
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• pp.650-663
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• 2021

The objective of this study was to examine the relationship between meat quality attributes and the changes of sarcoplasmic protein acetylation and myofibrillar protein acetylation in lamb longissimus thoracis et lumborum muscles at different postmortem phases. Protein acetylation, color, pH, shear force, myofibril fragmentation index and cooking loss were measured. The total level of acetylated sarcoplasmic proteins showed a negative relation with pH, a positive relation with a^*, b^* and cooking loss at the pre-rigor phase. Sarcoplasmic proteins acetylation affected postmortem pH by regulating glycolysis, which in turn affects color and cooking loss. The total level of acetylated myofibrillar proteins showed a positive relation with shear force at the pre-rigor phase. Myofibrillar proteins acetylation affected meat tenderness by regulating muscle contraction. This study indicated that acetylation played a regulatory role of meat color, water-holding capacity, and tenderization process at early postmortem.

• 한국항해항만학회지
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• 제27권5호
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• pp.585-591
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• 2003

최근 동북아의 중심에 위치하는 지리적 이점을 살려 부산항 및 광양항을 동북아 중심항(Hub-Port)으로 육성하고자 하는 동북아 물류(Logistics)중심화 전략이 적극적으로 추진되고 있다. 이와 같은 상황에서 경의선 및 동해선의 남북철도 연결공사는 그 의미가 크다고 할 수 있으며, 이것은 부산항이 동북아와 유럽을 육로로 잇는 해상과 철도수송의 연계를 위한 이상적인 복합운송체계(Combined Transport System) 를 갖추는 것을 의미한다. 그러나 지금까지의 연구와 정책은 남북척도의 연결에만 초점을 두고 실제 TKR (Trans-Korean Railway)의 기종점(Origin-Destination)으로서 가장 중요한 역할을 수행해야 하는 부산항 철도시설의 능력에 대한 검토는 없었다. 따라서 본 연구에서는 부산항을 중심으로 한 척도수송의 실태와 문제점을 제시하며, 향후 컨테이너 물동량 증가에 따른 부산항의 철도시설 능력을 검토하고 분석한다. 그리고 철송시설 능력에 따른 물류비용과 사회적비용 분석을 통하여 대구-부산간 경부고속철도(Gung-Bu Trans Express)와 같은 시설확충의 중요성과 철도수송 활성화를 위한 현실적 개선 방안을 제시한다.

• 한국항만학회지
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• 제11권2호
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• pp.321-337
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• 1997

Rapid change in the technological environment of marine transportation and the development of the ocean shipping industry have fostered a revolution in the port system. This in turn has caused major changes in the function and use of port in Korea. Aside from this. Mokpo Port, however continues to decline, because the existing port facilities and related subsystem are already obsolete with no chance of regaining operational effectiveness and treatment for proper implementation. Although a few studies have been done on the Mokpo Port, has not been found, any reseach for the analytical approach to the transportation system of it. This paper aims to make an extensive analysis of the physical distribution system in Mokpo Port focusing on the coordination of subsystems such as navigational aids system, quay handling and transfer system, storage system and inland transport system. The base of introduced simulation tool here is the queueing theory. The overall findings are as follows; 1. Among those vessels called at Mokpo Port in 1994, the average size of oceangoing vessels is 4,922.1 G/T, and the domestic is 317.8 G/T. The average arrival interval and service time of the domestic vessels are 6.0 hours and 24.1 hours respectively marking the berth occupation rate over 100%. Those for oceangoing vessels are 34.5 hours, 120.0 hours and 37.2%. In order to maintainin the berth occupation rate to 70% the capacity considering the 1994 of domestic piers must be extended to 145% and oceangoing vessels must be increased to 165% year called. 2. The capacity of approaching channel is enough to handle the total traffic volume. 3. Tugs are sufficiently being provided to handle all ships requiring their services 4. The capacity of storage and inland transportation systems are sufficient to handle the throughput and the yard stroage utilization rate of No.1 $\cdots$ No.5 is 4.5% and No.6 1S 30% of 1993's. 5. The utilization rate of LLc(Level Looping Crane) and PNT(PNeumaTic) are 2.7% and 18.8%, respectively. Practical solution and proposal for improvement of Transportation System in Mokpo Port are as follows; 1. To avoid the congestion in domestic pier introduction of a new port operation system is necessary allowing the domestic vessel to use the oceangoing pier. 2. To establish the port management information system to improve the efficiency of port operation. 3. To build a new storage system for high valued cargos including modernization of the present storage and handling system. 4. To insure the safety of navigation in approaching channel, The Vessel Traffic System including separation scheme is introduced. 5. To interest enormously on public relation to ship owner's association, shippers and consignees by showing that they can save cost and ship turnaround time in order to promote the call to Mokpo Port. At last, to be strategically change the function of Mokpo Port to the Leisure, Fishing & Ferry as well as Maritime port.

• Agricultural and Biosystems Engineering
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• 제3권2호
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• pp.73-78
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• 2002

Cabbage is one of the most important vegetable in Korea. The cabbage production was mainly based on human labor A comprehensive research fur substituting the human labor by machines has been performed until now. In general, cabbage is cultivated on hillside in Korea. Picking up the harvested cabbages in field and carrying to a vehicle fur transportation are very laborious work. Manual transportation of cabbage is likely to damage the quality and is also a cause to increase the cost of cabbage production. This study was to develop and evaluate a prototype cabbage loader fur efficient and safe transportation of cabbage. The developed loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transportation and loading of cabbage in a steep field. The maximum loading weight of the loader was 1.0 ton. By using two sets of safety devices attached to the loader to avoid the roll-over in a steep field, the static rollover slopes were increased up to 34.0% and 37.4% fur the left and the rear direction, respectively The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The loading capacity of the loader was about 35 pallets/hr when picking up, carrying, and unloading two cabbage pallets for one loading operation. The loading capacity was more than 8 times in comparison with the conventional human labor. The developed loader could be used fur loading and carrying the other vegetables. The study suggested a possible approach for designing the field machines operated on hillside.

• 벤처창업연구
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• 제1권2호
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• pp.225-253
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• 2006

본 연구는 고속철도(Korea Train Express: KTX)의 지역간 교통수단으로의 역할과 기능을 충실히 하기 위해서 개선이 필요한 사항을 철도공사에 재직 중인 직원들을 대상으로 설문조사하여 분석하였다. 그 결과는 다음과 같다. 첫째, 건설교통부의 합리적인 지역간 교통배분 정책이 필요하다. 우리나라 중장거리권역 교통수단분담률에서 승용차와 고속철도의 비교우위 분기점은 대전과 대구 사이로 나타나고 있다. 고속철도의 경우 자동차 및 항공기와 경쟁구간인 서울${\sim}$대구 구간의 영업에 집중하고 단거리 구간에서의 경쟁은 가능한 피하는 것이 바람직 할 것으로 여겨진다. 둘째, KTX 경영개선을 통한 수요증대가 요구된다. 철도공사 직원들은 전문인력 양성과 전문인력 관리가 필요하다고 인식하고 있다. 그리고 고속철도의 운영정책은 운임결정에 대한 자율권 확보가 필요하다고 인식하고 있었다.

• Steel and Composite Structures
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• 제22권5호
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• pp.1019-1038
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• 2016

The use of high-strength concrete (HSC) in precast concrete segmental bridges (PCSBs) can minimize the superstructure geometry and reduce beam weight, which can accelerate the construction speed. Dry joints between the segments in PCSBs introduce discontinuity and require special attention in design and construction. Cracks in dry joints initiate more easily than those in epoxy joints in construction period or in service. Due to the higher rupture strength of HSC, the higher cracking resistance can be achieved. In this study, shear behavior of dry joints in PCSBs was investigated by experiments, especially focusing on cracking resistance and shear strength of HSC dry joints. It can be concluded that the use of HSC can improve the cracking resistance, shear strength, and ductility of monolithic, single-keyed and three-keyed specimens. The experimental results obtained from tests were compared with the AASHTO 2003 design provisions. The AASHTO 2003 provision underestimates the shear capacity of single-keyed dry joint C50 and C70 HSC specimens, underestimates the shear strength of three-keyed dry joint C70 HSC specimens, and overestimates the shear capacity of three-keyed dry joint C50 HSC specimens.

• Computers and Concrete
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• 제19권4호
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• pp.395-404
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• 2017

In this paper, the mechanical property of CFRP, BFRP, GFRP and their hybrid FRP was experimentally studied. The elastic modulus and tensile strength of CFRP, BFRP, GFRP and their hybrid FRP were tested. The experimental results showed that the elastic modulus of hybrid FRP agreed well with the theoretical rule of mixture, which means the property of hybrid composites are linear with the volumes of the corresponding components while the tensile strength did not. The bearing capacity, peak strain, stress-strain relationship of circular concrete columns confined by CFRP, BFRP, GFRP and hybrid FRP subjected to axial compression were recorded. And the confinement effect of hybrid FRP on concrete columns was analyzed. The test results showed that the bearing capacity and ductility of concrete columns were efficiently improved through hybrid FRP confinement. A strength model and a stress-strain relationship model of hybrid FRP confined concrete columns were proposed. The proposed stress-strain model was shown to be capable of providing accurate prediction of the axial compressive strength of hybrid FRP confined concrete compared with Teng et al. (2002) model, Karbhari and Gao (1997) model and Miyachi et al. (1999) model. The modified stress-strain model was also suitable for single FRP confinement cases and it was so concise in form and didn't have piecewise fitting, which would be easy for use in structural design.