• 무역상무연구
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• 제35권
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• pp.3-38
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• 2007

As we know, D-terms which are constituted with DAF delivered the goods in a border place, DES delivered the goods on board a vessel at a vessel specified port on the buyer's side, DEQ delivered the goods on the quay on the buyer's side as the specified place, DDU and DDP delivered the good at the stipulated place at the agreed place or point, mean arrival contracts. DAF is designed mainly for railway carriage, DES and DEQ are designed mainly for vessel shipment, DDU and DDP are designed mainly for multimodal transportation. In spite of their original purpose of revision. They have in themselves many problems on notable points on application in practice. Therefore, in order to magnify their use, through revision of Incoterms, DAF is restricted to railway carriage, DES and DEQ are restricted to be used only for charter shipments. Particularly transport documents which seller should supply the buyer with under DDU and DDP are documents for ownership and possession rights to the goods loaded when executed in negotiable form like as CIF.

• International Journal of Fluid Machinery and Systems
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• 제3권1호
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• pp.29-38
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• 2010

This paper presents a procedure for the design optimization of a centrifugal compressor. The centrifugal compressor consists of a centrifugal impeller, vaneless diffuser and volute. And, optimization techniques based on the radial basis neural network method are used to optimize the impeller of a centrifugal compressor. The Latin-hypercube sampling of design-of-experiments is used to generate the thirty design points within design spaces. Three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model are discretized by using finite volume approximations and solved on hexahedral grids to evaluate the objective function of the total-to-total pressure ratio. Four variables defining the impeller hub and shroud contours are selected as design variables in this optimization. The results of optimization show that the total-to-total pressure ratio of the optimized shape at the design flow coefficient is enhanced by 2.46% and the total-to-total pressure ratios at the off-design points are also improved significantly by the design optimization.

• 산업경영시스템학회지
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• 제21권48호
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• pp.37-52
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• 1998

In many distribution systems important cost reductions and/or service improvements may be achieved by adopting an efficient inventory policy and proper selection of facilities. These efficiency improvements and service enhancements clearly require an integrated approach towards various logistical planning functions. The areas of inventory control and transportation planning need to be closely coordinated. The purpose of this paper is to construct an integrated model that can minimize the total cost of the transportation and inventory systems between multiple origin and destination points, where in origin point i has the supply of commodities and in destination point j requires the commodities. In this case, demands of the destination points are assumed random variables which have a known probability distribution. Using the lot-size reorder-point policy and the safety stock level that minimize total cost we find optimal distribution centers which transport the commodities to the destination points and suggest an optimal inventory policy to the selected distribution center. We also show if a demand greater than one unit will occur at a particular time, we describe the approximate optional replenishment policy from computational results of this lot-size reorder-point policy. This model is formulated as a 0-1 nonlinear integer programming problem. To solve the problem, this paper proposes heuristic computational procedures and a computer program with UNIX C language. In the usefulness review, we show the meaning and validity of the proposed model and exhibit the results of a comparison between our approach and the traditional approach, respectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.774-777
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• 2003

Importance of railway safety has drawn much attention with the growth of its contribution to the modernized society as a massive transport, high speed transportation system. Hence, safety regulations and organizations for railway vehicles are reviewed. The present status of domestic metro transit system is considered and compared with that of foreign countries. Some controversial points are raised and countermeasures are proposed.

• 한국항만경제학회지
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• 제27권1호
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• pp.247-262
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• 2011

본 논문은 광양항의 발전전략을 수립하기 위하여 SWOT/AHP분석을 실시하고자 한다. SWOT분석은 보통 전략수립단계에 있어서 내 외부 환경을 분석하기 위해서 사용된다. SWOT/AHP분석은 Kurttila et al(2000)이 SWOT분석의 유용성을 개선하기 위해 제안한 방법으로 SWOT분석의 결과는 단순히 SWOT그룹 내에 어떤 요인들이 있는가를 확인하는 것에 불과하다. 따라서 AHP분석과 결합함으로써 SWOT분석에서 도출된 요인들에 대한 상대적인 중요도를 평가하여 전략수립에 활용하는데 목적이 있다. 분석결과를 요약하면, SWOT그룹의 상대적 중요도는 기회(0.376), 강점(0.259), 위협(0.206), 약점(0.159) 순으로 나타났다. 다음으로 SWOT요인 별로 살펴보면, 강점요인의 상대적 중요도에서는 저렴한 화물처리비용(0.383), 우수한 항만입지(0.347), 광범위한 배후지(0.270) 순으로 나타났다. 약점요인의 상대적 중요도는 효율적인 통관시스템 미비(0.511), 복합운송 연계성 미비(0.315), 항만전문인력의 부족(0.173) 순으로 나타났다. 기회요인의 상대적 중요도는 각종 인프라 구축으로 수송체계 개선(0.461), 주변지역에 대한 연관산업단지 개발지속(0.326), 동북아지역의 물동량 증가추세(0.214) 순으로 나타났다. 위협요인의 상대적 중요도는 각종 인프라 구축으로 수송체계 개선(0.411), 주변항만과의 경쟁(0.400), 복합운송업체의 영세성(0.189) 순으로 나타났다. 평가대상이 되는 각 그룹별 세부요인들의 종합순위를 얻기 위하여 의사결정 항목들의 상대적 중요도를 종합화하였다. SWOT그룹별 세부속성요인들의 최종 중요도(가중치) 결과를 살펴보면, 기회요인 속하는 각종 인프라구축으로 인한 수송체계 개선(0.173), 주변지역에 대한 연관산업단지 개발지속(0.123)이 가장 높은 중요도를 보였고, 저렴한 화물처리비용, 우수한 항만입지, 항만운영의 융통성 결여, 주변항만과의 경쟁, 효율적 통관시스템 미비의 순으로 나타났다.

• 한국ITS학회 논문지
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• 제23권3호
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• pp.67-79
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• 2024

최근 키오스크, 스마트폰 등과 같은 디지털 기기의 활용 범위가 확대됨에 따라, 교통 분야에서도 교통수단 선택, 경로 및 도착 정보 확인 등 디지털 정보를 활용한 서비스가 활발하게 제공되고 있다. 본 연구는 디지털 기반 교통서비스 이용 시 사용자가 경험하는 불편함 경험 여부에 따른 이동성과의 관계를 분석하였다. 또한 이동성 영향요인에서 기술 활용 능력을 조절 변수로 선정하고 그에 대한 효과에 대해 검증하였으며, 결과는 다음과 같다. 첫째, 연구대상자의 특성에 따라 불편함을 경험한 비율은 16.4%, 이동성은 평균 48.4점이며, 기술 활용 능력은 3.78점인 것으로 나타났다. 둘째, 디지털 기반 교통서비스 불편함 경험은 종속변수인 이동성과 통계적으로 유의한 관계를 보이며, 정(+)의 관계를 보이는 것으로 분석되었다. 셋째, 기술 활용 능력의 조절 효과를 확인한 결과, 이동성과 유의한 정(+)의 관계를 보이는 것으로 도출되었다. 본 연구는 기술 활용 능력이 이동성에 미치는 영향에 대해 분석하여 제시함으로써 디지털 기반 교통서비스 이용 활성화와 디지털 격차 해소의 필요성에 대한 정책적 기초자료로 활용될 수 있다.

• 한국수정란이식학회지
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• 제26권3호
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• pp.165-169
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• 2011

The present study investigated the physiological evaluation of cloned mini-pigs in a transportable isolator. Transportable isolator was designed and manufactured by our research team for transporting gnotobiotic pig. Until now, no previous reports are available regarding the physiological activities and harmful effects when pigs were transported in this isolator. Five cloned mini-pigs of 1~2 year (s) old female with a body weight between 80~90 kg were used. The effects of transportable isolator on stress-related hormone, adrenocorticotrophic hormone (ACTH) and cortisol levels, and heart rate were evaluated. In addition, it was also examined the effects of transportable isolator on blood chemistry factors (alanine aminotransferase: ALT, aspartate aminotransferase: AST, blood urea nitrogen: BUN, glucose, and creatinine). Blood was sampled just before the beginning of transport (T0), at the end of transport (30min after the transport; T1), and 30 min after the end of transport (T2). At the same time, heart rate was also evaluated. As a result, heart rate had no significant (p>0.05) differences at the various-time points of study (T0, T1, T2). However, heart rate was slightly higher than normal range in T1 and T2. The ACTH level was higher than normal range. Whereas, the cortisol level was lower than normal range. There were no statistical significant differences both ACTH and cortisol level between different time groups. Also, there were no significant differences in blood chemistry factors. Therefore, our present study shows that transportable isolator has no harmful effect on stress and physiological condition in cloned mini-pigs.

• 미생물학회지
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• 제48권2호
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• pp.57-65
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• 2012

인은 인지질, 탄수화물 및 핵산 등의 생분자 합성에 필요한 원소이다. 세균은 외부환경으로부터 인산이나 인산을 포함하는 영양소를 흡수하여 인을 얻고, 세포대사에 사용되고 남은 인산은 polyphosphate 형태로 저장한다. 현재까지 알려진 다섯 개의 인산 수송 시스템 중, 인산에 특이적으로 높은 친화력을 갖는 Pst 시스템이 가장 중요한 역할을 하며, 그 발현은 세포외부 인산 농도에 반응하는 PhoB-PhoR two component 신호전달 시스템에 의해 조절된다. 반응 조절 단백질 PhoB는 인산 대사뿐 아니라 이와 관계없는 유전자들의 전사를 조절하는 것으로 알려졌으며, 따라서 PhoB의 활성이 조절되지 않으면 많은 종류의 다른 표현형이 나타난다. 본 총설은 각 인산 수송 시스템의 기능이 결여된 세균의 표현형에 대한 최근 연구 결과를 토대로 다음과 같은 내용을 기술하였다. 첫째, 세포 내부 인산의 적정 농도 유지를 위한 인산 수송 시스템들의 역할, 둘째, 인산뿐 아니라 여타 환경 신호와 관련된 수송 시스템의 다양한 표현형, 그리고 마지막으로, 수송 시스템들 간 혹은 그 조절자들 간의 표현형 중복을 분류하여 제시하였다. 이러한 내용은 결국 세균의 대사, 적응반응 및 병원성 발현에 미치는 인산 항상성의 중요성을 강조한다.

• 한국지반환경공학회 논문집
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• 제15권4호
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• pp.13-27
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• 2014

Catchments soil erosion, one of the most serious problems in the mountainous environment of the world, consists of a complex phenomenon involving the detachment of individual soil particles from the soil mass and their transport, storage and overland flow of rainfall, and infiltration. Sediment size distribution during erosion processes appear to depend on many factors such as rainfall characteristics, vegetation cover, hydraulic flow, soil properties and slope. This study involved laboratory flume experiments carried out under simulated rainfall in a 3.0 m long ${\times}$ 0.8 m wide ${\times}$ 0.7 m deep flume, set at $17^{\circ}$ slope. Five experimental cases, consisting of twelve experiments using three different sediments with two different rainfall conditions, are reported. The experiments consisted of detailed observations of particle size distribution of the out-flow sediment. Sediment water mixture out-flow hydrograph and sediment mass out-flow rate over time, moisture profiles at different points within the soil domain, and seepage outflow were also reported. Moisture profiles, seepage outflow, and movement of overland flow were clearly found to be controlled by water retention function and hydraulic function of the soil. The difference of grain size distribution of original soil bed and the out-flow sediment was found to be insignificant in the cases of uniform sediment used experiments. However, in the cases of non-uniform sediment used experiments the outflow sediment was found to be coarser than the original soil domain. The results indicated that the sediment transport mechanism is the combination of particle segregation, suspension/saltation and rolling along the travel distance.

• Wind and Structures
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• 제20권5호
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• pp.643-660
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• 2015

The wind tunnel test of large-scale sectional model and computational fluid dynamics (CFD) are employed for the purpose of studying the aerodynamic appendices and mechanism on suppression for the vortex-induced vibration (VIV). This paper takes the HongKong-Zhuhai-Macao Bridge as an example to conduct the wind tunnel test of large-scale sectional model. The results of wind tunnel test show that it is the crash barrier that induces the vertical VIV. CFD numerical simulation results show that the distance between the curb and crash barrier is not long enough to accelerate the flow velocity between them, resulting in an approximate stagnation region forming behind those two, where the continuous vortex-shedding occurs, giving rise to the vertical VIV in the end. According to the above, 3 types of wind fairing (trapezoidal, airfoil and smaller airfoil) are proposed to accelerate the flow velocity between the crash barrier and curb in order to avoid the continuous vortex-shedding. Both of the CFD numerical simulation and the velocity field measurement show that the flow velocity of all the measuring points in case of the section with airfoil wind fairing, can be increased greatly compared to the results of original section, and the energy is reduced considerably at the natural frequency, indicating that the wind fairing do accelerate the flow velocity behind the crash barrier. Wind tunnel tests in case of the sections with three different countermeasures mentioned above are conducted and the results compared with the original section show that all the three different countermeasures can be used to control VIV to varying degrees.