• Water Engineering Research
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• 제3권2호
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• pp.85-92
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• 2002

There has been continuous efforts to manage water resources for the required water quality criterion at river channel in Korea. However, we could obtain the partial improvement only for the point sources such as, waste waters from urban and factory site through the water quality management. Therefore, it is strongly needed that the best management practice throughout the river basin fur water quality management including non-point sources pollutant loads. This problem should be resolved by recognizing the non-point sources pollutant loads from the upstream river basin to the outlet of the basin depends on the landuse and soil type characteristics of the river basin using the computer simulation by a distributed model based on the detailed investigation and application of Geographic Information System (GIS). The purpose of this study is consisted of the three major distributions, which are the investigation of spread non-point sources pollutants throughout the river basin, development of the base maps to represent and interpret the input and outputs of the distributed simulation model, and prediction of non-point sources pollutant loads at the outlet of a up-stream river basin using Agricultural Non-Point Sources Model (AGNPS). For the validation purpose, the Seom-Jin River basin was selected with two flood events in 1998. The results of this application showed that the use of combined a distributed model and an application of GIS was very effective fur the best water resources and quality management practice throughout the river basin

• 대한조선학회논문집
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• 제49권3호
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• pp.254-263
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• 2012

The survivability of warship is assessed by susceptibility, vulnerability and recoverability. Essentially, a vulnerability assessment is a measure of the effectiveness of a warship to resist hostile weapon effects. Considering the shot line and its penetration effect on the warship, present study introduces the procedural aspects of vulnerability assessments of warship. Present study also considers the prediction of penetration damage to a target caused by the impact of projectiles. It reflects the interaction between the weapon and the target from a perspective of vulnerable area method and COVART model. The shotline and tracing calculation have been directly integrated into the vulnerability assessment method based on the penetration equation empirically obtained. A simplified geometric description of the desired target and specification of a threat type is incorporated with the penetration effect. This study describes how to expand the vulnerable area assessment method to the penetration effect. Finally, an example shows that the proposed method can provide the vulnerability parameters of the warship or its component under threat being hit through tracing the shotline path thereby enabling the vulnerability calculation. In addition, the proposed procedure enabling the calculation of the component's multi-hit vulnerability introduces a propulsion system in dealing with redundant Non-overlapping components.

• 대한의용생체공학회:의공학회지
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• 제36권1호
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• pp.16-21
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• 2015

Indocyanine green(ICG) and 5-aminolevulinic acid(5-ALA) have been widely used to mark blood vessels or tumors. However, fluorescent dye detection systems were designed to use one type of dyes only. In this study, we proposed a detection system capable of detecting Indocyanine green and 5-aminolevulinic acid. Multiple filters and light sources are integrated into a single system. In this study, we performed analysis of fluorescent dyes and configured a detection system. During the analysis, it was found that Indocyanine green and 5-aminolevulinic acid have the maximum intensity at $40{\mu}M$. We designed light source for fluorescent dyes and conducted compatibility test using a commercial surgical microscope. The fluorescent dye detection system was configured based on the experimental results. The developed system successfully detects Indocyanine green and 5-aminolevulinic acid. Therefore, more efficient surgical operations can be achieved using both fluorescent dyes at the same time. We expect that the developed system can increase the survival rate of patients.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.379-387
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• 2015

A custom power device provides an integrated solution to the present problems that are faced by the utilities and power distribution. In this paper, a new controller is designed which is connected to a multiconverter unified power quality conditioner (MC-UPQC) for improving the power quality issues adopted modified synchronous reference frame (MSRF) theory with Fuzzy logic control (FLC) technique. This newly designed controller is connected to a source in order to compensate voltage and current in two feeders. The expanded concept of UPQC is multi converter-UPQC; this system has a two-series voltage source inverter and one shunt voltage source inverter connected back to back. This configuration will helps mitigate any type of voltage / current fluctuations and power factor correction in power distribution network to improve power quality issues. In the proposed system the power can be conveyed from one feeder to another in order to mitigate the voltage sag, swell, interruption and transient response of the system. The control strategies of multi converter- UPQC are designed based on the modified synchronous reference frame theory with fuzzy logic controller. The fast dynamics response of dc link capacitor is achieved with the help of Fuzzy logic controller. Different types of fault conditions are taken and simulated for the analysis and the results are compared with the conventional method. The relevant simulation and compensation performance analysis of the proposed multi converter-UPQC with fuzzy logic controller is performed.

• International Journal of Fluid Machinery and Systems
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• 제6권2호
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• pp.105-112
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• 2013

The application of contra-rotating rotors for higher specific speed pump has been proposed in our studies, which is in principle effective for reducing the rotational speed and/or the pump size under the same specification of conventional axial flow pump. In the previous experiments of our prototype, the cavitation inception at the tip region of the rear rotor rather than that of the front rotor and the strong potential interaction from the suction surface of the rear rotor blade to the pressure surface of the front one were observed, indicating the possibility to further improve the pump performance by optimizing rotational speed combination between the two rotors. The present research aims at the design of rear rotor with lower rotational speed. Considering the fact that the incoming flow velocity defects at the tip region of the rear rotor, an integrated inflow model of 'forced vortex' and 'free vortex' is employed. The variation of maximum camber location from hub to tip as well as other related considerations are also taken into account for further performance improvement. The ideas cited above are separately or comprehensively applied in the design of three types of rear rotor, which are subsequently simulated in ANSYS CFX to evaluate the related pump performance and therefore the whole low speed design idea. Finally, the experimental validation is carried out on one type to offer further proofs for the availability of the whole design method.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.237.1-237.1
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• 2010

Recent developments such as concern over global warming, depletion of fossil fuels and increase in energy demands by the increasing world population has eventually lead to mass production of electricity using renewable sources. Ocean contains energy in form of thermal energy and mechanical energy: thermal energy from solar radiation and mechanical energy from the waves and tides. The current paper looks at generating power using waves. The primary objective of the present study is to maximize the primary energy conversion (first stage conversion) of the base model by making some design changes. The model entire consisted of a numerical wave tank and the turbine section. The turbine section had three components; front guide nozzle, augmentation channel and the rear chamber. The augmentation channel further consisted of a front nozzle, rear nozzle and an internal fluid region representing the turbine housing. Different front guide nozzle configuration and rear chamber design were studied. As mentioned, a numerical wave tank was utilized to generate waves of desired properties and later the turbine section was integrated. The waves in the numerical wave tank were generated by a piston type wave maker which was located at the wave tank inlet. The inlet which was modeled as a plate wall which moved sinusoidally with the general function, $x=asin{\omega}t$. In addition to primary energy conversion, observation of flow characteristics, pressure and the velocity in the augmentation channel, rear chamber as well as the front guide nozzle are presented in the paper. The analysis was performed using the commercial code of the ANSYS-CFX. The base model recorded water power of 29.9 W. After making the changes, the best model obtained water power of 37.1 W which represents an increase of approximately 24% in water power and primary energy conversion.

• 전자공학회논문지CI
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• 제42권2호
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• pp.39-48
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• 2005

본 논문은 기존의 인터넷이나 유선 온라인을 이용하여 멀티미디어 원격제어 시스템을 설계 및 구현하였다. 또한 응용 프로그램(EzPlay PC-EPG)을 개발하여 사용자 환경에 적합한 편의성을 제공한다. 멀티미디어 원격 제어 시스템은 USB 타입으로 연결된 PC/TV 통합 무선 송${\cdot}$수신으로 구성되어 있으며, EzPlay 응용 프로그램은 PC/TV 모니터 화면에 적합한 UI 모드 환경을 제공하여 다양한 컨텐츠론 이용한 수 있는 편리한 시스템이다. 제안된 방법은 신호 탐지 제어 이론에 기반을 둔 응용 프로그램으로 인터넷 망을 이용하여 실시간 재생, 예약 녹화, 저장을 하는 기능을 가진다. PC-EPG 시스템은 서버/클라이언트 형태의 웹 프로그램으로 구현되며 클라이언트 컴퓨터의 데이터 저장은 TCP/IP를 통행 Visual C++/MFC 프로그램으로 구현된 클라이언트 프로그램에서 수신처리 된다. 또한 사용자의 필요성에 따라서 프로그램 데이터베이스를 구축하여 정보를 제공하는 지능형 프로그램 기능을 포함한다.

• 항공우주시스템공학회지
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• 제14권5호
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• pp.83-90
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• 2020

재난·재해는 우리 사회의 인명과 재산에 막대한 피해를 주고 있으며, 국가적으로 해결해야 할 사회문제로서 인식되고 있다. 사물인터넷, 인공지능, 드론(무인기), 빅 데이터와 같은 4차 산업혁명 기술들은 과학·기술적 사회문제해결 도구로서 재난·안전산업 분야에도 흡수되면서 사회 전반에 영향을 미치고 있다. 국내 무인기 관련 29개 기관/기업은 재난치안 현장에서 운용 가능한 멀티콥터형 소형무인기 통합시스템 구축('17~'20)을 완료할 예정이다. 본 논문은 국가 재난대응 체계의 전략 자산으로서 재난치안용 무인기의 중장기적인 발전 방향을 고찰하고자 한다. 먼저, 재난안전 산업 및 정책 동향을 분석하고, 소형무인기 개발현황 및 향후계획, 부족기술 확보, 경쟁력 강화 방안 고찰을 통해 개발전략, 특화임무, 플랫폼, 통신, 관제, 운용 측면에서 재난치안용 무인기의 단계별 연구개발 방향을 제안한다.

• 대한인간공학회지
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• 제36권5호
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• pp.535-543
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• 2017

Objective: This study was designed to identify factors affecting pilots' +Gz tolerance recovery from +Gz induced exhaustion. Background: +Gz tolerance of pilots has been considered as a crucial factor to fly the modern high performance fighter aircrafts. However, the factors affecting pilots' G-tolerance recovery from +Gz induced exhaustion have not been examined in the acceleration research community. Method: A centrifuge profile consisting of a high +Gz run for pilot's exhaustion and a low +Gz run for pilot's recovery and another high +Gz runs for pilot's second exhaustion was designed. The subjects' +Gz tolerance recovery ratio was measured by ratio of second high +Gz run time to the first high +Gz run time. The subjects' +Gz tolerance recovery rate was measured by dividing the subjects' +Gz tolerance recovery ratio by the low +Gz run time. The subjects' G-tolerance recovery rate was analyzed with respect to the subjects' personal factors including subjects' anthropometric and physiologic characteristics, flight time, flying aircraft type and so on. Results: The subjects' previous three-month flight hours (r=-0.336, p=0.039), six-month flight hours (r=-0.403, p=0.012) and one-year flight hours (r=-0.329, p= 0.044) correlated with the subjects' G-tolerance recovery rate. Conclusion: The subjects' G-tolerance recovery rate is clearly related to the subjects' previous flight hours. However, the subjects' anthropometric and physiologic characteristics do not show any statistically significant correlation with the subjects' G-tolerance recovery rate. Application: This research provides a safety critical insight to aviation community by identifying the factors to affect the gravity-induced loss of consciousness (GLOC) of pilots.

• 동아시아경상학회지
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• 제2권4호
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• pp.56-64
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• 2014

Today, travelers are provided large amount information which includes Web sites and tourist magazines about introduction of tourist spot. Many approaches have been proposed to analyze the large amount of available information with the aim of discovering the most popular Points of Tourist Interest and routes. However, it is not easy for users to process the information in a short time. Therefore travelers prefer to receive pertinent information easier and have that information presented in a clear and concise manner. Whether you are looking for banks by company, foreign exchange services, free wireless hotspots, touristic attractions, campsites, supermarkets, restaurants, cinemas, The aim of POI Tourism Services is to enable tourists to find spots that only the locals know, giving the tourists opportunity to the tourists to explore new areas of the place like never before. This paper proposes find the scope for a personalized service for tourist "Special Interest Tourism" recommendation for tourists who travel within India & for the benefit of Foreign Nationals who visit the country. The major focus of the study is to understand the demand for such a service being integrated into the conventional tour package. The major findings made during the course of the show that the market for "Special Interest Tourism" based services stands at approximately 63%. Travel today is mainly for the people from the middle income group having a fixed budget while traveling and would like economic travel solutions that fit their budget. This accounts for a major part of the market for the service. Most tourist prefer to go on week end getaways or trips that last more than a week, this means that a specialized trip plan based on the travelers interests is feasible with these type of travelers. Maximum demand for "Special Interest Tourism" based services would be during the festive seasons.