• 한국지하수토양환경학회지:지하수토양환경
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• 제22권6호
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• pp.66-73
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• 2017

Empirical erosion models like Universal Soil Loss Equation (USLE) models have been widely used to make spatially distributed soil erosion vulnerability maps. Even if the models detect vulnerable sites relatively well utilizing big data related to climate, geography, geology, land use, etc within study domains, they do not adequately describe the physical process of soil erosion on the ground surface caused by rainfall or overland flow. In other words, such models are still powerful tools to distinguish the erosion-prone areas at large scale, but physics-based models are necessary to better analyze soil erosion and deposition as well as the eroded particle transport. In this study a physics-based soil erosion modeling system was developed to produce both runoff and sediment yield time series at watershed scale and reflect them in the erosion and deposition maps. The developed modeling system consists of 3 sub-systems: rainfall pre-processor, geography pre-processor, and main modeling processor. For modeling system validation, we applied the system for various erosion cases, in particular, rainfall-runoff-sediment yield simulation and estimation of probable maximum sediment (PMS) correlated with probable maximum rainfall (PMP). The system provided acceptable performances of both applications.

• 대한의용생체공학회:의공학회지
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• 제26권1호
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• pp.43-47
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• 2005

We have developed a small bore x-ray CT for small animal imaging with a linear x-ray detector array and small-scale slip rings. The linear x-ray detector array consists of 1024 elements of 400□m×400□m with a gadolinium oxysulfide (GOS) scintillator on top of them. To avoid use of expensive large diameter slip rings for projection data transmission from the X­ray detector to the image reconstruction system, we used the wireless LAN technology. The projection data are temporally stored in the data acquisition system residing on the rotating gantry during the scan and they are transmitted to the image reconstruction system after the scan. With the wireless LAN technology, we only needed to use small-scale slip rings to deliver the AC electric power to the X-ray generator and the power supply on the rotating gantry. The performances of the small animal CT system, such as SNR, contrast, and spatial resolution, have been evaluated through experiments using various phantoms. It has been experimentally found that the SNR is almost linearly proportional to the tube current and tube voltage, and the minimum resolvable contrast is less than 30 CT numbers at 40kVp/3.0㎃. The spatial resolution of the small animal CT system has been found to be about 0.9Ip/㎜. Postmortem images of a piglet is also presented.

• 한국항해항만학회지
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• 제32권10호
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• pp.777-783
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• 2008

입자영상속도계(PIV)의 해석에 웨이블릿 변환을 적용하여 정성적인 유동정보뿐만 아니라 공간분해능을 갖는 정량적인 속도장 정보를 제공하고 있다 이 기법은 기포유동(bubbly flow)과 같은 다상(multi-phase)의 유동구조를 해석하는 데도 유용하게 살일 수 있다. 본 연구에서는 기체와 액체의 이상유동(two-pase flow)에 PIV기법을 적용하고 이산 웨이블릿 변환을 사용하여 유장해석을 수행함으로써, 기포를 포함한 속도장 특성과 유동특성을 조사한다.

• 의학교육논단
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• 제18권2호
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• pp.90-98
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• 2016

Assessment tools for non-academic qualities such as ethics frequently employ hypothetical scenarios to lay out a contextual framework underlying the corresponding criteria of assessment. Due to the context-specific nature of the assessment criteria, details of the scenarios become very important in obtaining accurate results. This study aims to explore how medical school applicants differ in ethical decision making depending on the types of ethical dilemma scenarios, and how they correlate with academic achievements after admission. In 2014, all 82 applicants invited for an admission interview for a graduate-entry program were asked to complete a questionnaire comprised of 13 hypothetical scenarios. There were three domains (unethical business decisions, unethical academic decisions, and sexual quid pro quos) and participants were made to choose between the profitable-but-unethical choice or the unprofitable-but-ethical choice, using a four-point Likert-type scale. On average, tendencies toward unethical decisions were lowest for sexual favors ($1.34{\pm}0.46$), and highest for gaining academic advantages ($2.22{\pm}0.56$). Unethical decisions for academic advantages and sexual benefits showed significant correlation respectively with the female gender and those who graduated from overseas universities. In addition, the propensity for choosing unethical academic decisions was significantly correlated with high academic achievements in medical school (r=0.396). Not only does this study demonstrate that different levels of ethical decision making depend on the scenarios, but also those differences may be a determinant factor in subsequent academic performances in medical school. In conclusion, given the possible influence of the details of the hypothetical scenarios to the applicant's responses, careful consideration must be given during their development.

• 한국항만경제학회지
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• 제31권2호
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• pp.1-21
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• 2015

본 연구는 최근 10여 년간의 한중일 3국간의 무역량 증대 및 관광객 증가 현상과 함께, 한중 및 한일 카페리항로의 시장여건 변화를 고찰하고자 함이 목적이다. 한중 및 한일 카페리항로는 각각 상이한 발전 역사를 가져왔으며 상품 서비스의 라이프싸이클 이론에 있어서 시장여건이 상이하다. 기존 관련 연구들이 개별적인 항로를 대상으로 분절된 시각으로 카페리시장을 연구한 까닭으로, 우리나라 국제카페리 항로의 시장여건에 대한 보다 체계적이고 종합적인 이해가 부족하였다고 보인다. 이러한 배경에서 본 논문은 2000년 이후 2012년 사이의 한중 및 한일 카페리항로의 시장현황을 조사하고 카페리선사의 경영성과를 평가하였으며, 카페리항로별 시장여건 변화에 대한 통계적 분석을 실시하였다. 마지막으로 한중 및 한일 카페리항로의 시장 수명주기별 단계를 진단하고 향후 전망에 대하여 고찰하였다. 연구의 성과로는 카페리항로별로 화물 및 여객 수요의 향후 전망은 다소 상이하였으며, 전반적으로 성장둔화 및 침체가 예상되었고, 경쟁하는 수송수단간의 상관관계분석에서도 항로별 상이한 시장환경에 처한 것으로 분석되었다. 하지만 선사경영 성과분석에서 두 항로 환경은 성장성과 수익성이 나빠졌다는 점이 공통적이었다. 분석결과를 종합적으로 보면 한중항로는 성장기에서 성숙기 단계로 진입하고 한일 항로는 성숙기 심화 중으로 판단되고, 각 항로는 상이한 시장여건에 대응할 발전전략을 구축함이 시급하다고 주장하였다.

• 산업경영시스템학회지
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• 제38권4호
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• pp.168-176
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• 2015

Trends of integrating products and services lead to the emergence of Product-Service System (PSS). To implement and embody a PSS solution in new product development, a comprehensive design framework is allowed designers to facilitate the design factors of the PSS in complex business environments. A physical product, containing functionalities for services, is the role of medium between customers and a manufactures. Customers can access those metaphysical interfaces to utilize the product fully or expand its performances. The PSS is aiming to prolong its lifecycle while maintaining its expected quality. Since the quality can be represented as a measure which belongs to user's perspective, guaranteeing certain level of quality can be interpreted to sustaining customer satisfaction. The objective of this paper is to propose a PSS design framework to identify design factors for developing products and services by integrating object-oriented concepts and blueprinting in context of a business ecosystem. The proposed model is developed based on relationship products and services matching with their design factors. The products and the services are then brought together to form a PSS. Functions and processes can be categorized to identify the design factors in different levels using the object-oriented concepts. Objected-oriented concepts provide PSS analysis tools for describing a business process or a workflow process in the PSS. The blueprint is used to identify the relationships between the products functions and the service processes that are offered as part of a job. To demonstrate of the effectiveness of the proposed model, we use a case study involving a smart phone.

• 대한조선학회논문집
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• 제41권3호
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• pp.60-71
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• 2004

Nowadays, We have had a growing interest in high-speed vessels' because it is very important to save time and cost in marine transportation. The development of hull form for high-speed vessels is high priority to secure the competitive power for the transportation of cargos. Therefore, the demand of the high-speed vessels is gradually increased, but the conventional hull forms are limited by rapidly increasing resistance upon the increase of ship speed in high-speed region. Therefore, new concepts for the hull form of high-speed vessels have been requested. One of the derived hull forms for that demand is the hull form of trimaran type. Trimaran has a very slender main hull as compared with conventional single hull so that is reduced in wave resistance. The slender main hull has the undesirable characteristics of stability, but two side hulls make up for the week points in the stability. That is, trimaran is able to have desirable performances for the resistance and stability. In this paper, for the design of 200TEU class container vessel with trimaran type, which will be cruised in Yellow-Sea region, firstly a preliminary hull is designed, and the model test is carried out with the variation of side hull position. From the experience of the preliminary hull form design, an improved hull form for the 200TEU container are designed, and the model tests are carried out. Also, a numerical computation technique is adopted for the simulation of flow phenomena around the designed hull forms. The final hull form is compared with existing ships for the resistance performance from the computation with computer and ship model tests.

• 대한조선학회논문집
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• 제46권6호
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• pp.667-674
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• 2009

The researches on the development of composite material underwater vehicle propeller have been actively attempted for the reduction of radiation noise with outstanding damping effects. Composite material propellers have almost been designed and produced by the foreign experts, and it is difficult to obtain the related informations about their flow, vibration, material characteristics because they are treated as the secrets with close relationship to the military technology, especially in the case of underwater vehicles. For the security of domestic manufacture of composite material propeller and the comparison and examination of its performance and radiation noise characteristics with those of German CONTUR composite material propeller, two propellers were self-produced according to the fiber weaving and array using compressible molding process and their self performances and radiation noise characteristics were measured. The mean fluctuations of blade tip of self-produced composite material propeller were increased and the radiation noises in the low frequency band were reduced compared to those of CONTUR, which could be estimated as the change of material characteristics and also be thought to be used for the future research informations.

• 한국인터넷방송통신학회논문지
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• 제21권6호
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• pp.117-122
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• 2021

자율주행은 자동차가 사람 없이 운전할 수 있도록 해 주며 최근 인공지능 기술의 발전에 힘입어 매우 활발히 연구되고 있다. 인공지능 기술 중에서도 특히 심층 강화 학습이 가장 효과적으로 사용되는데 이를 위해서는 적절한 활성화 함수를 이용한 신경망 구축이 필수적이다. 여태껏 많은 활성화 함수가 제시됐으나 적용 분야에 따라 서로 다른 성능을 보여주었다. 본 논문은 교차로에서 자율주행을 학습하기 위해 심층 강화 학습을 사용할 때 어떤 활성화 함수를 사용하는 것이 효과적인지 성능을 비교 평가한다. 이를 위해 평가에서 사용할 성능 메트릭을 정의하고 각 활성화 함수에 따른 메트릭의 값을 그래프로 비교하였다. 그 결과 Mish를 사용할 경우 보상이 다른 활성화 함수보다 평균적으로 높은 것을 알 수 있었고 보상이 가장 낮은 활성화 함수와의 차이는 9.8%였다.

• 한국콘텐츠학회논문지
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• 제21권6호
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• pp.197-206
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• 2021

이 연구는 대구·경북 대학들이 지역신문에 게재한 광고들을 대상으로 게재 구조와 메시지를 살펴보았다. 2020년 7월 1일부터 1차 수시모집기간 이전인 9월 22일까지 지역신문과 한국대학신문에 게재된 지역 대학의 신문광고를 전수 조사하였다. 그 결과, 대학들은 매일신문, 영남일보, 경북일보, 대구일보, 대구신문 등의 순서로 광고 게재를 선호하였다. 이를 지역단위로 나누어 다시 분석해보니, 대학들은 대구와 포항 지역에 소재한 신문을 선호하였다. 둘째, 산학협력과 대학기본역량진단 그리고 특성화 관련 단어들이 광고 메시지의 상위에 등장하였다. 이를 4년제와 2, 3년제로 나누어 분석한 결과, 4년제는 중장기 발전계획을 드러낸 소구가 더 자주 등장하였다. 반면 2, 3년제 대학은 가시적인 성과를 강조한 소구를 빈번하게 사용하였다. 이 연구에서는 대구·경북을 중심으로 광고를 통해 대학과 신문의 관계를 파악하고, 급변하는 환경 속에 발맞춰 변화한 대학 광고의 메시지를 분석했다.