수중운동체 방사소음의 로이드 미러 효과 연구

강승희,Kang, Seung-Hee 한국음향학회 2021 韓國音響學會誌 Vol.40 No.4

The measurement of the Underwater Radiated Noise (URN) for the underwater vehicle should consider both the acoustic interference due to the surface reflection and the calculation of the Closet Point of Approach (CPA). In this paper, I tried to analyze the underwater vehicle's URN using the Lloyd's mirror effect. First, the theoretical Lloyd's mirror pattern was compared with the sea trial result, and the sea trial results corresponded well with the theoretical predicted pattern. And then the CPA distance could be estimated by the Lloyd's mirror pattern. As a results, acoustic source level shows the spectral fluctuation due to the acoustic interference of the Lloyd's mirror effect.

진도관리 자동화를 위한 자료수집기술(DAT) 선정 방법

강승희,정영수,Kang, Seung-Hee,Jung, Young-Soo 한국건설관리학회 2012 한국건설관리학회 논문집 Vol.13 No.1

건설 프로젝트의 성과 측정 및 관리에 있어 진도관리는 기본적이며 핵심적인 업무기능이다. 오랜 기간 동안 다양한 진도 관리 기법이 연구 개발되고 있음에도 불구하고, 자료수집을 위한 과도한 업무부담은 체계화된 진도관리의 장애요소로 지적되어 왔다. 최근 자료수집기술(Data Acquisition Technology, DAT)의 발전은 자동화된 진도관리의 기회를 제공하고 하고 있다. 그럼에도 불구하고 지금까지의 DAT 연구는 특정 공종 또는 특정 기술에 집중하고 있어, 건설사업 전체의 진도관리 자동화에 대한 연구는 이루어지지 않았다. 이러한 관점에서, 본 연구는 건설사업 공종별 최적의 DAT를 선정하는 방법론을 제안하였다. DAT 선정방법은 각 공종별 진도측정의 방법, 대상, 범위, 기술 등의 유형을 분류하여, 이를 DAT 특성별로 최적치를 도출하는 알고리즘으로 구성된다. 제안된 방법론의 검증을 위하여 사례 프로젝트를 이용한 기계적 분석을 실시하고 또한 실무자 평가를 수행한 결과, 대부분 공종에서 동일한 결과를 얻었다. 또한 사례현장 평가결과 중의 하나로서, 노무자의 층별 출입정보를 RFID를 활용하여 측정하는 것이 가장 효율적이며 가장 많은 공종에 적용이 가능한 것으로 나타났다. Progress measurement provides project participants with valuable information in terms of 'current status', 'corrective countermeasure', and 'forecast of future risks'. However, the managerial effort (or workload) required to acquire and maintain detailed progress data has been the major barrier to practical implementation. Even though recent efforts in utilizing data acquisition technologies (DATs) have actively attempted to automate the progress measurement process, previous DAT research has only been focused on limited construction tasks or selected technologies. This paper proposes a DAT selection algorithm that automatically assign an appropriate DAT for every commodity item for an entire constriction project. Five different criteria were identified and developed in order to comprehend specific requirements for automating the progress measurement of each commodity group. A case-study and also a survey from practitioners were conducted in order to validate the proposed methodology.

측풍 조건을 고려한 로터블레이드 형상의 공력성능에 대한 실험적 연구

강승희,유기완,Kang, Seung-Hee,Ryu, Ki-Wahn 한국항공운항학회 2017 한국항공운항학회지 Vol.25 No.2

In the present study, a wind tunnel test for a rotor-blade configuration was conducted to investigate a basic aerodynamic performance and a effect of the cross wind. The diameter of the configuration was 1.46 m and the test was carried out for both a clean and a tripped configurations. The boundary layer for the trip configuration was simulated by zig-zag tape and the test performed on constant-velocity and constant-rotational modes. It was shown that the test result for the tripped configuration reduces the maximum power coefficient by 9.4% ~ 12.1% compared to the clean one. Within $5^{\circ}$ of the flow angle, there is no significant loss of power, however, the coefficient is reduced by 5.3% ~ 36.7% in the range of $10^{\circ}{\sim}30^{\circ}$.

회전타원체 보빈 형상의 거동에 관한 연구

강승희,안성호,임완권,김혜웅,Kang, Seung-Hee,Ahn, Sung-Ho,Rim, One-Kwon,Kim, Hye-Ung 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.5

The initial trajectory of a spheroid configuration bobbin for precision guidance has been investigated by analyzing its aerodynamic load and six-degree-of-freedom motion. The effects of changes in the spheroidal head configuration, flow angle and lateral center-of-gravity offset are numerically studied using the commercial software "FLUENT". A wind tunnel test is also conducted to validate the numerical scheme and to examine effect of the Reynolds number on the flow around the bobbin. It is shown that the size of the separation bubble formed on the surface decreases significantly when the Reynolds number is varied between 110,000 and 140,000. At a zero flow angle, an oblate spheroidal head shows relatively moderate rotation while a prolate spheroidal head shows rapid rotation. The bobbin with a spherical head shape has little effect on the flow direction; however, the oblate bobbin is sensitive to the flow angle. The roll motion of the bobbin is greatly influenced by the lateral center-of-gravity offset and maximum dispersion is observed at half of the radius.

성인 남자의 의복구매동기와 자아개념과의 관계 연구

강승희,이명희 ( Seung Hee Kang,Myoung Hee Lee ) 대한가정학회 1993 Family and Environment Research Vol.31 No.1

CdSe/ZnS 나노결정 양자점 Pyrolysis 제조와 발광다이오드 소자로의 응용

강승희,키란쿠마르,손기철,허훈회,김경현,허철,김의태,Kang, Seung-Hee,Kumar, Kiran,Son, Kee-Chul,Huh, Hoon-Hoe,Kim, Kyung-Hyun,Huh, Chul,Kim, Eui-Tae 한국재료학회 2008 한국재료학회지 Vol.18 No.7

We report on the light-emitting diode (LED) characteristics of core-shell CdSe/ZnS nanocrystal quantum dots (QDs) embedded in $TiO_2$thin films on a Si substrate. A simple p-n junction could be formed when nanocrystal QDs on a p-type Si substrate were embedded in ${\sim}5\;nm$ thick $TiO_2$ thin film, which is inherently an n-type semiconductor. The $TiO_2$ thin film was deposited over QDs at $200^{\circ}C$ using plasma-enhanced metallorganic chemical vapor deposition. The LED structure of $TiO_2$/QDs/Si showed typical p-n diode currentvoltage and electroluminescence characteristics. The colloidal core-shell CdSe/ZnS QDs were synthesized via pyrolysis in the range of $220-280^{\circ}C$. Pyrolysis conditions were optimized through systematic studies as functions of synthesis temperature, reaction time, and surfactant amount.

MS에서 분리한 CPS1균 처리가 ‘Cardinal’ 장미 절화수명과 품질에 미치는 영향

강승희(Seung-Hee Kang),전윤태(Yun-Tae Chun),조경철(Kyung-Cheol Cho),지연태(Youn-Tae Chi),정순주(Soon-Ju Chung) 한국원예학회 2000 원예과학기술지 Vol.18 No.2

공학 전공 대학생의 창의성에 나타나는 성차

강승희(Seung-Hee Kang),윤소정(Sojung Yune) 한국기계가공학회 2015 한국기계가공학회지 Vol.14 No.5

Recently, it has been emphasized that more girls should be able to contribute to society in the engineering field. However, there is little research for understanding the psychological characteristics of female engineering students. We first must understand their capabilities in order to take advantage of the strengths of female engineering college students. Based on this understanding, it is necessary to provide future educational interventions for them. Therefore, the purpose of this study was to investigate the gender differences in creativity in engineering education. Additionally, we wanted to know whether the differences were domain-specific or domain-general differences. For this, we targeted 351 engineering students in Busan and Daegu. An integrated creativity test and engineering creativity test were carried out. It was found that female engineering students had lower scores on both the integrated creativity and engineering creativity tests than male students. These results suggest that we should develop and apply appropriate strategies to enhance the creativity of female students in engineering education.

B축 회전 기능을 갖춘 복합공구대 구조물의 정/동적 안정성에 관한 연구

강승희(Seung-Hee Kang),김재실(Chae-Sil Kim) 한국기계가공학회 2014 한국기계가공학회지 Vol.13 No.1

Techniques of tool posts are developing such that variable machining is possible using only one machine for the complication of a product"s shape and to reducethe machining time. In order to develop a mill turret with a variable machining function with the mounting of mill turret units on a B-axis tilting table, we determine the static/dynamic stability ofthe structure of the mill turret. To this end, a static structural analysis and a modal analysis wereconducted. From the results of the static structural analysis, the maximum stress was found to be less than the allowable stress. By the comparing the results of the modal analysis ofthe excitation frequencies ofthe mill turret, there wereno resonance regions found. Therefore, the mill turret with theB-axis tilting facility is shown to have good structural integrity.

폐쇄형 풍동 시험부내의 원형 실린더 유동에 대한 비정상 벽면효과 연구

강승희(Seung-Hee Kang),권오준(Oh Joon Kwon),홍승규(Seung-Kyu Hong) 한국항공우주학회 2005 韓國航空宇宙學會誌 Vol.33 No.7

풍동 시험부 비정상 벽면효과에 대한 연구를 위해 폐쇄형 시험부내의 원형 실린더 주위 유동장에 대한 수치적 연구를 수행하였다. 수치기법은 Roe의 flux-difference-splitting을 사용한 격자점 중심 유한체적법과 이중시간 전진 기법을 사용하는 내재적 시간적분법을 사용하였다. 계산 결과 폐쇄형 시험부에는 실린더 주위 비정상 유동장에 압력구배를 강화시켜 실린더의 양력 및 항력의 진폭을 크게 하고, 실린더 뒷전에서의 기저압력을 작게 하여 항력을 증가시키는 벽면효과가 있음을 확인하였다. 또한, 이러한 시험부 벽면은 실린더 와류 shedding 주파수를 커지게 하는 효과가 있다. 시험부 벽면에서의 압력은 벽면효과가 포함된 shedding 주파수를 기본으로 하는 고조파 현상을 보인다. For study on the unsteady wall interference effect, flows around a circular cylinder in closed test-section wind tunnels have been numerically investigated by solving compressible Navier-Stokes equations. The numerical scheme is based on a node-based finite-volume method with the Roe's flux-difference splitting and an implicit time-integration method coupled with dual time-step sub-iteration. The computed results showed that the unsteady pressure gradient over the cylinder is enhanced by the wall interference, and as a result the fluctuations of lift and drag are augmented. The drag is further increased because of the lower base pressure. The vortex shedding frequency is also increased by the wall interference. The pressure on the test section wall shows the harmonics having the shedding frequency contained in the wall effect.