• 한국항해항만학회지
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• 제34권1호
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• pp.65-70
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• 2010

워터프런트의 온화한 기후특성과 함께 자연이나 개방성 그리고 그러한 것들을 포함하는 축제성이 시민 생활환경의 질 향상이라는 요구에 대응하기에 적합한 공간이라는 특징 때문에 부산에서는 해안지역 워터프런트의 개발이 수익의 극대화를 위해 초고층 건축물 위주로 개발이 진행되고 있다. 그러나 이러한 초고층 위주의 개발은 토지피복의 변화와 더불어 풍속을 약화시키기 때문에 개발에 의해 기후특성이 변화될 가능성이 크다고 할 수 있다. 본 연구에서는 초고층 개발에 따른 워터프런트의 기후변화를 파악하기 위해 최근 초고층 건축물 위주의 개발이 집중되고 있는 부산의 해운대 지역을 대상으로 개발 전후의 기후특성을 비교 검토하여 개발 이후 해운대의 겨울에 따뜻하고 여름에 시원한 해안지역 기후특성이 변화하여 여름의 기온상승이 현저하며 열대야일수가 증가하였음을 밝혔다.

• Advances in aircraft and spacecraft science
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• 제6권4호
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• pp.333-348
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• 2019

Low fuel regression rate is the main drawback of hybrid rocket which should be overcome. One of the improvement techniques to this problem is usage of a solid fuel grain with a complicated geometry port, which has been promoted owing to the recent development of additive manufacturing technologies. In the design of a hybrid rocket fuel grain with a complicated geometry port, the understanding of fuel regression behavior is very important. Numerical investigations of fuel regression behavior requires a capturing method of solid fuel surface, i.e. gas-solid interface. In this study, level set method is employed as such a method and the preliminary numerical tool for capturing a hybrid rocket solid fuel surface is developed. At first, to test the adequacy of the numerical modeling, the simulation results for circular port are compared to the experimental results in open literature. The regression rates and oxidizer to fuel ratios show good agreements between the simulations and the experiments, after passing enough time. However, during the early period of combustion, there are the discrepancies between the simulations and the experiments, owing to transient phenomena. Second, the simulations of complicated geometry ports are demonstrated. In this preliminary step, a star shape is employed as complicated geometry of port. The slot number effect in star port is investigated. The regression rate decreases with increasing the slot number, except for the star port with many slots (8 slots) in the latter half of combustion. The oxidizer to fuel ratio increases with increasing the slot number.

• 한국항해학회지
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• 제14권3호
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• pp.15-33
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• 1990

In recent years, propellers with various blade configurations such as highly skewed propellers are often fitted to ships from the viewpoint of reduction of vibration and noise. In the design of such propellers, design charts based on methodical series tests are to be complemented by theoretical calculations for accurate estimation of propeller open-water characteristics. The author intended to develop a method to estimate propeller open-water characteristics based on Quasi -Vortex - Lattice Method originally developed by Lan for solving planar thin wings, The Quasi - Vortex - Lattice Method has the simplicity and flexibility of Vortex - Lattice Method. Its accuracy is comparable to that of the Vortex - Lattice Method. Converged solution can be obtained with a small number of control points and further, leading edge suction force can be calculated directly. In the present paper, a numerical method to estimate propeller open-water characteristics based on the Quasi - Vortex - Lattice Method is reviewed and its application to marine propellers is described in detail. Comparison of propeller open-water characteristics obtained by the present method with experimental data showed good agreement for a wide variety of propellers including highly skewed propellers.

• 한국기록관리학회지
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• 제14권3호
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• pp.127-151
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• 2014

이 연구에서는 '항구도시 부산'이라는 이미지를 형성하는 데 큰 역할을 한 부산항은 부산의 대표적인 로컬리티 공간이므로 부산항과 인근지역의 경관에 관한 사진, 엽서 등 이미지 기록을 중심으로 <부산항 사진 아카이브>를 구축하는 과정과 방법을 구체적으로 기술함으로써 로컬리티의 재현방법론을 확산하고 공유하고자 한다. 사진, 엽서 등 이미지 기록, 즉 사진기록의 특성을 문자 위주의 텍스트 기록과 비교하여 그 특성을 살펴보고, 이미지 기록의 대중 친화적인 특성에 주목하여 부산항에 관한 사진, 엽서 등의 이미지 기록을 수집하여 오픈소스 기록관리 소프트웨어 가운데 사진의 전시에 적합한 오메카(Omeka)를 이용하여 사진 아카이브를 실험적으로 구축해 보았다. 그 과정과 방법을 보면, 먼저 아카이브 구축 목적에 따른 개발 원칙을 세우고, 기록 수집을 위한 기초조사를 실시하였다. 부산항 관련 기록 소장기관과 개인소장가 등의 저작권 동의를 얻어서 원본 또는 파일을 수집하였다. 이후 수집한 기록은 더블린코어에 따라 기술하였으며, 시기에 따른 컬렉션을 구성하고 기록을 정리하였다. 부산항의 공간적 성격을 교통공간, 역사공간, 산업공간, 생활공간으로 구분하고, 11개 전시주제를 구상하였다. 전시의 보기로 교통공간의 부관연락선을 제시하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.259-264
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• 2000

The functions of the plug valve are the control of flow rate as well closing and opening pipe lines. Analyses on the flow characteristics in plug valve port are required to improve the performance and safety at severe operating conditions such as high-pressure and high-temperature. In this study, numerical analyses are carried out with varying the opening rate (fraction of the full open to close) of the valve and the shapes of valve Uk: straight, convex, concave and mixed shapes. The parameters influencing the flow characteristics in the valve are the discharge coefficient( $C_v$) and the resistance coefficient( K). Therefore, the distributions of static pressure, velocity vector and stream lines are investigated, and $C_v$ and K are calculated in each opening rate and shape. In case of full open, the static pressure passed through the valve port has almost been recovered. However, in case of other opening rates, the pressure does not permanently regained due to pressure drop leading to loss. This phenomenon in each shape of the valve shows the different behaviors. Calculation results show that the mixed shape has the best flow attribute.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.141-152
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• 1999

This study aims at advancing waterfront planning and development of North Harbor of Pusan and attempting to establish an identity through the analysis and case studies of waterfront development of foreign countries. This study is based on Pusan urban harbor plan and the case study which was investigated the relational port with an urban area to find a model of development method and procedure of urban waterfront renewal, The approach of this study is to classify diversified cases and to suggest elements after reviewing successful cases. The point in the waterfront development plan of North Harbor of Pusan is how to secure an amenity on the edge and provides a comprehensive theoretical base such as skyline, coastline, green area, accessibility, scenery, landmark, open space, and so on. The result of this study is useful for the planner to develop more and systematic approaches which could utilize waterfront. Waterfront development will be a new chance of urban development for Pusan.

• Journal of Gastric Cancer
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• 제24권1호
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• pp.57-68
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• 2024

Reduced-port gastrectomy (RPG) includes all procedures derived from various efforts to minimize surgical invasiveness, with single-incision laparoscopic gastrectomy (SILG) being the ultimate reduced-port technique. However, there are challenges related to its feasibility, oncological validity, training, and education. This review describes the current issues and challenges, as well as the future prospects of RPG for gastric cancer. Gastrectomy, which started as an open surgery, has evolved into a laparoscopic surgery. With the advancements in laparoscopic technology, SILG has been used to minimize surgical scarring. However, owing to the technical difficulties of SILG, cases involving the addition of 1 trocar or needle grasper alongside the multichannel port have also been reported. Additionally, 3-port laparoscopic gastrectomy (3PLG) using only 3 trocars is also being performed. RPG, as a concept, includes a range of approaches such as SILG, 2-port laparoscopic gastrectomy, and 3PLG. These techniques aimed to reduce the number of ports or incisions required for laparoscopic gastrectomy. Despite technical difficulties, RPGs offer numerous advantages, including minimal invasiveness, excellent cosmetic outcomes, and the potential for improved postoperative recovery, such as reduced length of hospital stay and post-operative pain. It could be considered similar to conventional laparoscopic gastrectomy, and may not be oncologically inferior. Ongoing studies, such as the KLASS 12, are required to gain further insights.

• Journal of Gastric Cancer
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• 제23권3호
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• pp.487-498
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• 2023

Purpose: Reduced port surgery (RPS) for gastric cancer has been frequently reported in distal gastrectomies but rarely in total gastrectomies. This study aimed to determine the feasibility of 3-port totally laparoscopic total gastrectomy (TLTG) with overlapping esophagojejunal (EJ) anastomosis. Materials and Methods: A total of 81 patients who underwent curative TLTG for gastric cancer (36 and 45 patients with 3-port and 5-port TLTG, respectively) were evaluated. All 3-port TLTG procedures were performed with the same method as 5-port TLTG, including EJ anastomosis with the intracorporeal overlap method using a linear stapler, except for the number of ports and assistants. Short-term outcomes, including the number of lymph nodes (LNs) harvested by station and postoperative complications, were analyzed retrospectively. Results: Clinical characteristics were not significantly different among the groups, except that the 3-port TLTG group was younger and had a lower rate of pulmonary comorbidity. There were no cases of open conversion or additional port placement. All operative details and the number of harvested LNs did not differ between the groups, but the rate of suprapancreatic LN harvest was higher in the 3-port TLTG group. No significant differences were observed in the overall complication rates between the 2 groups. Conclusions: Three-port TLTG with overlapping EJ anastomoses using a linear stapler is a feasible RPS procedure for total gastrectomy to treat gastric cancer.

• Structural Engineering and Mechanics
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• 제12권6호
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• pp.615-632
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• 2001

Ductility of open piled wharves under reversed cyclic loads has been investigated. Experimental testing of five wharf models having a scale of about 1:4 was conducted under the application of horizontal reversed cyclic loading. The experiments were designed to focus on the horizontal ultimate load, ductility and failure mode of the considered wharf models. Nonlinear numerical analyses using the finite element method were also performed on numerical models representing the experimentally tested wharves. The results of the experimental tests showed that open piled wharves possessed favourable ductile behaviour and that their load bearing capacity did not depreciate until a ductility factor of 3 to 4 was reached. The numerical analysis showed that the relative rotation that took place at the joints between the steel piles and the R.C. beam was responsible for a considerable portion of the total horizontal deformation of the wharves. Therefore, it was concluded that introducing the joint stiffness in calculating the deformations of open piled wharves was important to achieve reasonable accuracy.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.221-226
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• 2006

Around 2002, the United States Coast Guard (USCG) identified a need to re-capitalize their Reference Station (RS) and Integrity Monitor (IM) equipment used in the Nationwide Differential Global Position System (NDGPS). Commercially available off-the-shelf differential RS and IM equipment lacked the open architecture required to support long-term goals that include future system improvements such as use of new civil frequencies on L2 and L5 and realization of a higher rate NDGPS beacon data channel intended to support RTK. The first step in preparing for this future NDGPS was to port current RTCM SC-104 compatible RS and IM functionality onto an open architecture PC-based platform. Trimble's product Charisma is a PC-based RS and IM software designed to meet these USCG goals. In fact USCG engineers provided key designs and design insights throughout the development. We cannot overstate the contribution of the USCG engineers. Fundamental requirements for this effort were that it be sufficiently flexible in hardware and software design to support fluid growth and exploitation of new signals and technologies as they become available, yet remain backward compatible with legacy user receivers and existing site hardware and system architecture. These fundamental goals placed an implicit adaptability requirement on the design of the replacement RS and IM. Additionally, project engineers were to remain focused on sustaining the high level of differential GPS service that 1.5 million legacy users have come to depend on. This paper will present new hardware and software (i.e., Trimble's Charisma software) architecture for the next generation NDGPS RS and IM. This innovative approach to engineering on an open architecture PC-based platform allows the system to continue to fulfill legacy NDGPS system requirements and allows the USCG and others to pursue a scalable hardware re-capitalization strategy. We will use the USCG's recapitalization project to explain the essential role of the Charisma software.