• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.352-359
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• 2010

In recent years, the market has shown increasing interest in pump-turbines. The prompt availability of pumped storage plants and the benefits to the power system achieved by peak lopping, providing reserve capacity, and rapid response in frequency control are providing a growing advantage. In this context, there is a need to develop pumpturbines that can reliably withstand dynamic operation modes, fast changes of discharge rate by adjusting the variable diffuser vanes, as well as fast changes from pumping to turbine operation. In the first part of the present study, various flow patterns linked to operation of a pump-turbine system are discussed. In this context, pump and turbine modes are presented separately and different load cases are shown in each operating mode. In order to create modern, competitive pump-turbine designs, this study further explains what design challenges should be considered in defining the geometry of a pump-turbine impeller. The second part of the paper describes an innovative, staggered approach to impeller development, applied to a low head pump-turbine project. The first level of the process consists of optimization strategies based on evolutionary algorithms together with 3D in-viscid flow analysis. In the next stage, the hydraulic behavior of both pump mode and turbine mode is evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Finally, the progress in hydraulic design is demonstrated by model test results that show a significant improvement in hydraulic performance compared to an existing reference design.

• 한국해양공학회지
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• 제20권3호
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• pp.82-87
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• 2006

An approach to model a high-speed monohull vessel is introduced. The high-speed monohull form belonging to the category of multihull is drawing new attention, due to the rapidly growing trend of fast passenger ships and military purpose. Multihull forms are much thinner in their overall shape, compared to those of the conventional commercial vessels. Moreover, the parent hull forms are not readily obtainable when a new design is intended, which makes it hard to perform various technical calculations in terms of hull optimization, hydrodynamic computation, structural design, and so forth. In this paper, a parametric technique is used to design a high-speed hull form. To model a hull form, NURBS (Non Uniform Rational B-Spline) representation is used. The goal of research is to provide a fast and convenient tool to design an initial hull form with fewer parameters available in the early design stage. The technique employed in this paper will be applied to the design of multihull forms, such as catamaran, trimaran, and semi-swath.

• 한국작물학회지
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• 제26권1호
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• pp.103-109
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• 1981

담배의 엽탈락, 품질 및 수량에 미치는 석회와 붕사의 영향을 알고자 시험한 결과를 요약하면 다음과 같다. 1. 엽탈락 이식후 40～80일에 많이 발생되며 불위엽에서 상위엽으로 진행된다. 2. 석회의 시용은 엽탈락을 조장하나 붕사는 엽탈락을 현저히 감소시켰다. 3. 석회의 시용은 전당, Lignin, 붕소함량을 감소시키며 붕사시용은 붕소와 Lignin 함량을 증가시킨다. 4. 붕사의 1년시용으로 엽탈락의 완전방지는 어려웠다. 5. 석회와 붕사의 시용량은 각각 120kg/10a,1.2kg/10a가 엽탈락방지와 품질, 수량성으로 보아 적정시용량으로 인정되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.930-933
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• 2005

Non-destructive inspection techniques using laser have been breading their application areas as well as growing their measurement skills together with the rapid development of circumferential technology like fiber optics. computer and image processing The ESPI technique is already on the stage of on-line testing with commercial products in developed country nations. Especially, this technique is expected to be applied to the nuclear industry, automobile and aerospace because it is proper for the vibration measurement and it can be applied to objects of a high temperature. This paper describes the use of the ESPI system for measuring vibration patterns on the reflecting objects. Using this system, high-quality Jo fringes for identifying mode shapes are displayed. A bias vibration is introduced into the reference beam to shift the Jo fringes so that fringe shift algorithms can be used to determine vibration amplitude. Using this method. amplitude fields for vibrating objects were obtained directly from the time-average interferometer recorded by the ESPI system.

• Kidney Research and Clinical Practice
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• 제35권2호
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• pp.69-77
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• 2016

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, and its pathogenesis is complex and has not yet been fully elucidated. Abnormal glucose and lipid metabolism is key to understanding the pathogenesis of DN, which can develop in both type 1 and type 2 diabetes. A hallmark of this disease is the accumulation of glucose and lipids in renal cells, resulting in oxidative and endoplasmic reticulum stress, intracellular hypoxia, and inflammation, eventually leading to glomerulosclerosis and interstitial fibrosis. There is a growing body of evidence demonstrating that dysregulation of 50 adenosine monophosphate-activated protein kinase (AMPK), an enzyme that plays a principal role in cell growth and cellular energy homeostasis, in relevant tissues is a key component of the development of metabolic syndrome and type 2 diabetes mellitus; thus, targeting this enzyme may ameliorate some pathologic features of this disease. AMPK regulates the coordination of anabolic processes, with its activation proven to improve glucose and lipid homeostasis in insulin-resistant animal models, as well as demonstrating mitochondrial biogenesis and antitumor activity. In this review, we discuss new findings regarding the role of AMPK in the pathogenesis of DN and offer suggestions for feasible clinical use and future studies of the role of AMPK activators in this disorder.

• 한국IT서비스학회지
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• 제20권4호
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• pp.81-93
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• 2021

In the era of artificial intelligence, the use of 'artificial intelligence-based services' has been diversified by combining various smart devices, big data, and voice recognition technology with artificial intelligence. From the perspective of IT services, these services are important technology that cause a paradigm shift from display-centered to voice-centered, and from passive to active IT-based services. This study seeks to find a solution to the current situation where AI assistant service is still in its beginning stage, despite having been ten years since its release and having a growing number of consumer touch points. Accordingly, we categorized the functions of AI assistant services and identified the degree of importance and satisfaction of services recognized by actual users. In order to define the 'ideal' services of AI assistant, seven experts from AI assistant-related industry have participated in the interview. Based on this result, we investigated the importance and satisfaction of services perceived by actual users of AI assistant services. As a result of IPA (Importance Performance Analysis). we find out which services are potentially 'keep', 'concentrate', 'low priority', or 'overkill' and provide various implications from the findings.

• 한국군사과학기술학회지
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• 제21권6호
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• pp.894-903
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• 2018

In the case of helicopters, the development of parts technology is rapidly changing, and the complexity is rapidly increasing. Particularly, the surge of various electric and electronic systems is recognized as a problem that is directly related to the safety of the helicopter. Due to these problems, there is a growing interest in reliability evaluation in the face of the problem of confirming and certifying the reliability of parts in the development stage. In this paper, the analysis of the failure mechanism of the wiper system was carried out, and the priority and importance of each failure mode were checked by using the results, and major stress factors were derived and the corresponding acceleration model was selected. Also, the accelerated lifetime test time was calculated according to the life test time, acceleration status and acceleration level of the steady state by using the selected acceleration model and characteristic values.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.157-159
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• 2019

홀로그램 기술은 3차원 객체의 생성, 전송, 재생 관점에서 기술 개발이 활발히 수행되고 있지만 현재 여러 가지 한계로 인하여 답보상태에 머물러 있다. VR, AR을 넘어 새로운 기술의 요구에 부합하기 위해 중간 단계로 유사홀로그램 시장이 성장하고 있는 추세다. 홀로그램의 기술의 핵심은 point cloud 형태의 방대한 3차원 데이터를 생성하고 그 방대한 데이터를 통신망을 통해 실시간으로 전송하여 목적지에서 원본과 같이 재생하는 것이다. 본 연구에서는 방대한 3차원 데이터를 실시간으로 전송하기 위한 방법으로 생성된 3차원 객체 정보의 특징점을 전송하여 목적지에서 원본과 비슷한 형태의 객체로 재생하는 방법에 대해 연구한다.

• 디지털융복합연구
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• 제17권11호
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• pp.517-522
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• 2019

많은 비즈니스에서 챗봇은 사용자의 질문에 가장 즉각적이고 직접적인 피드백으로 제공함으로써 사용자 경험을 높여가고 있으며 그 활용 영역이 커져가고 있다. 본 연구에서는 챗봇의 정의를 비롯해 명령방식, 기능, 플랫폼에 따른 세 가지 유형을 구분되는 요소에 따라 분류해 보았다. 그 과정에서 기능적 구분 요소는 패턴인식, 자연어처리, 시멘틱 웹, 텍스트 마이닝, 상황인식 컴퓨팅의 기능적 부분의 핵심 기술 요소가 챗봇 UX를 위해 필요하지만 현재 단계에서의 한계도 알 수 있었다. 이를 바탕으로 더 나은 사용자 경험을 위한 챗봇의 UX요소를 페이스북, 스카이프, 텔레그램, 구글어이스턴트를 대상으로 분석하였으며 카드와 같은 기본 UI요소와 빠른 응답, 명령, 영구 메뉴의 적용이 사용자 경험요소로 필요함을 알 수 있었다.

• 한국농촌건축학회논문집
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• 제22권4호
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• pp.71-78
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• 2020

Today, the whole world is going through a big chaos due to the COVID-19, but paradoxically, the emergence of COVID-19 has been leading to the need for sustainable development, such as Green New Deal that can improve global warming and carbon emissions, and the need for sustainable architecture is growing bigger and bigger in the architectural field as well. The level of CLT buildings in Korea is at a very rudimentary stage, while CLT buildings remedying existing wooden buildings are getting the spotlight among European countries for sustainable architecture. This study was conducted to categorize structure layer compositions of overseas CLT buildings and analyze architectural techniques and materials applied by collecting and analyzing information about CLT structure layer compositions of overseas CLT building-related institutions, companies and cases. When classifying structure layer compositions of foreign CLT buildings depending on the roles of layers. it was revealed that exterior wall structure layers were combined and organized within a sequence of external finishing, ventilation, waterproof, board, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing, sloped roof structure layers were external finishing, ventilation, waterproof, board, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing, flat roof structure layers were external finishing, ventilation, waterproof, planking wood, external insulation, waterproof, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing.