• 한국지능시스템학회논문지
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• 제23권3호
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• pp.268-274
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• 2013

임의의 비선형 시스템을 제어하기 위한 새로운 방법의 제어 알고리즘이 널리 보고되고 있으며, 그 유용성을 입증하기 위한 제어 대상 시스템으로 역진자 시스템이 널리 활용되고 있다. 본 논문에서는 스프링으로 연결된 2개의 차량에 장착된 역진자를 제어하는 알고리즘을 제시한다. 여기서 두 개의 차량 중 하나는 구동용, 다른 하나는 역진자를 장착한 무구동용이다. 이를 위한 시스템 모델링을 제시하고, 퍼지논리제어 시스템 기반의 양질의 제어기 설계를 제안한다. 본 논문에서는 퍼지논리제어기의 입력변수로 사용될 6개의 변수를 2개로 축소하기 위하여 LQR(Linar Quadratic Regulator) 기법을 도입하며, 이를 통하여 퍼지논리제어기 설계의 복잡성을 줄일 수 있음을 보인다. 더욱이 개선된 2-입력 퍼지논리제어기의 제어 규칙표가 skew-symmetric의 특성을 가지는 성질로부터 다시 단일입력 퍼지논리제어기 설계를 제안한다. 제안한 방법의 유용성을 입증하기 위하여 시뮬레이션을 수행하며, 이를 통하여 제안한 방법의 우수성을 입증한다.

• 한국자동차공학회논문집
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• 제24권3호
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• pp.302-309
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• 2016

Urea-SCR system is currently regarded as promising NOx reduction technology for diesel engines. SCR system has to achieve maximal NOx conversion in combination with minimal $NH_3$ slip. In this study, model based open loop control for urea injection was developed and assessed in the European Transient Cycle (ETC) for heavy duty diesel engine. On the basis of the transient modeling, the kinetic parameters of the $NH_3$ adsorption and desorption are calibrated with the experimental results performed over the zeolite based catalyst. $NH_3$ storage or surface coverage of SCR catalyst can not be measured directly and has to be calculated, which is taken into account as a control parameter in this model. In order to reduce $NH_3$ slip while maintaining NOx reduction, $NH_3$ storage control algorithm was applied to correct the basic urea quantity. If the actual $NH_3$ surface coverage is higher than the maximal $NH_3$ surface coverage, the urea injection quantity is significantly reduced in the ETC cycle. By applying this logic, the resulting $NH_3$ slip peak can be avoided effectively. With optimizing the kinetic parameters based on standard SCR reaction, it suggests that a simplified, less accurate model can be effective to evaluate the capability of model based control in the ETC cycle.

• 디자인학연구
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• 제14권4호
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• pp.127-136
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• 2001

The decay of the Old Chinese Dynasty, Tang in the 10th century caused the collapse of the political order of Southeast Asia and the neighboring countries began to try to go their own way. Japan abolished the system called "Yudangsa" and nourished the culture of Japanese style. The fang age had a respect of the′Japanese Character Culture", in which when we expressed the sound, they developed the Japanese letters ,that is, reduced Chinese characters, and systematized them as linguistic symbols and developed them into one of letter design styles. The Japanese letters which was mainly the media of the expression of the female literature were delicately shaped ′as natural materials, which finally resulted in Japan′s oldest letter modeling, Asite Letter Design Style. The Japanese letters were blended with ′Reeds around the Lake", "Sea Birds", "Birds′flying", and "Rocks", mixed with the overall shapes of the objects and assimilated into one part, and became a means for the main entertainment of the nobility such as "Singing Festival", "Conference", and "Ceremonial Events" According to the relics, the Japanese feeling of a small cosmos was represented with the fabulous skills of artifacts. In audition, "Play Painting"in the countryside is also a kind of Asite the ordinary people accepted as wit and satire. What we will have to notice is about exchange of the Chinese letter designs, when the thought focused ′on the letter design, Jobcheso was popular. The letter design Jobcheso is -a kind of letter design which represents -natural objects and was popular at the time of Yukjo Dynasty, and there are some documents of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to have been "Japanese Letter Jobcheso." Therefore, the purpose of this study is to look into the origin of the letter designs in the Chinese character culture circle, in terms of the letter design of Jobcheso.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 춘계학술대회 논문집
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• pp.385-390
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• 2005

LMTT(Linear Motor-based Transfer Technology)는 항만 자동화를 위한 수평 이송 시스템이며, 셔틀카(shuttle car)와 격자구조의 레일에 부착된 스테이터 모듈(stator module)로 구성된 PLMSL(Permanent Magnetic Linear Synchronous Motor)에 의해 구동된다. 본 논문에서는 LMTT시스템 부품인 이동체(mover)의 경량화를 위하여 직교배열표 및 크리깅 방법을 이용하여 최적설계를 수행한다. 설계변수로는 가로빔, 세로빔, 휠빔의 두께와 높이 방향의 치수를 결정하는 형상변수를 포함시켰다. 목적함수로는 중량, 제한조건 함수로는 안전율이 고려된 응력으로 설정하였다. 본 연구에서 제시된 방법으로 구한 최적해를 민감도기반 최적설계로 구해진 최적해와 비교, 검토하였다.

• Design & Manufacturing
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• 제1권1호
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• pp.7-11
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• 2007

The fabrication of precision optical components by deterministic CNC grinding is an area of great current interest. Replacement of the traditional, craftsman driven, optical fabrication process is essential to reduce costs and increase process flexibility and reliability. Moreover, CNC grinding is well suited to the fabrication of complex shapes such as aspheres, making it possible to design optical systems with fewer components and reduced weight. Current technology is capable of producing surfaces with less than 2 microns peak to valley error, 50 nm rms surface roughness, and less than 1 micron subsurface damage. Bound abrasive tools, in which the abrasive particles are fixed in a second (matrix) material, play an important part in achieving this performance. In this paper, the factors affecting the ultra-fine surface roughness and profile accuracy of machined surfaces of aspheric parts has been analyzed experimentally and theoretically and on ultra-precision aspheric grinding system and precise adjusting mechanism have been designed and manufactured. In the paper we report the results of experiments and modeling performed to examine the effects of machinability, occurring during grinding of optical surfaces, on the tool surface profile. Profiles of machined surface were measured by using SEM. In order to optimize grinding conditions of aspheric lens processing, we performed experiments by design of experiments.

• 대한토목학회논문집
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• 제3권1호
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• pp.13-24
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• 1983

장주기파(長週期波)에 의한 항내(港內)의 반응(反應)을 예측(豫測)하기 위하여 비선형(非線型) 편미분방정식(偏微分方程式)으로 표현(表現)되는 2차원(二次元) 부정류(不定流)의 운동방정식(運動方程式)과 연속방정식(連續方程式)을 확정(確定)하고, 이 식(式)들에 Abbott의 Implicit 형(型) 차분형(差分型)을 적용(適用)하여 유한(有限) 차분방정식(差分方程式)의 형태(形態)로 유도(誘導)한 후(後), double sweep 알고리즘에 의하여 해석(解析)하는 수학적(數學的) 모형(模型)을 개발(開發)하였다. 본(本) 모형(模型)은 임의(任意)의 파형(波形), 풍속(風速)과 수심(水深), 위도(緯度) 등(等)을 입력자료(入力資料)로 하여 임의(任意)의 지형(地形)을 가진 항내(港內)에서의 반응(反應)을 해석(解析)할 수 있도록 설계(設計)되었다. 특(特)히 파향(波向), 이송항(移送項), 항입구(港入口)로 되돌아 나오는 에너지의 방사현상(放射現象) 등(等)을 수치해석적(數値解析的)으로 처리(處理)하는 수법(手法)의 개발(開發)에 관(關)하여 연구(硏究)하였다. 본(本) 모형(模型)에 의한 해석결과치(解析結果値)는 1차원(次元) 및 2 차원(次元) 정진동(靜振動)(seiche) 수치실험(數値實驗)을 통(通)하여 검정(檢定)하였으며, Ippen과 Goda의 이론해석치(理論解析値) 및 실험결과치(實驗結果値)와 비교(比較)하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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• pp.1344-1367
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• 2014

Mobile traffic is increasing a masse because of the propagation of the Internet and the development of wireless mobile technology. Accordingly, the Network Local Mobility Management (NETLMM) working group [1] of the Internet Engineering Task Force (IETF) has standardized Proxy Mobile IPv6 (PMIPv6) [2] as a protocol for accomplishing the transmissibility of mobile terminals. PMIPv6 is a network-led IP-based mobility management protocol, which can control terminal mobility without depending on the type of access system or the capability of the terminal. By combining PMIPv6 and the mobility of Session Initiation Protocol (SIP), we can establish terminal mobility and session mobility through a more effective route. The mobility function can be improved and the overlap of function reduced as compared to that in the case of independent operation. PMIPv6 is appropriate for a non-real-time service using TCP, and SIP is appropriate for a real-time service using RTP/UDP. Thus, in the case of a terminal using both services, an effective mobility management is possible only by using PMIPv6 together with SIP. In order to manage mobility in this manner, researches on PMIPv6-SIP are in progress. In line with this trend, this paper suggests a new PMIPv6-SIP architecture where when a mobile terminal conducts a handover, a network-led handover while maintaining the session without the addition of a special function or middleware is possible along with effective performance evaluation through mathematical modeling by comparing the delay and the packet loss that occur during the handover to the Pure-SIP.

• 유통과학연구
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• 제15권3호
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• pp.81-89
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• 2017

Purpose - Universities are fostering the development of closer relationships with students due to the increase in competition among universities. Universities are placing greater emphasis on relationship quality as a source of competitive advantage. Thus relationship marketing has become an important strategic theme in higher education. The purpose of this study is to investigate the effects of faculty trustworthiness on relationship building process in the context of relationship marketing. For this study, faculty trustworthiness is divided into competence, benevolence, and integrity. And relationship development variables are composed of satisfaction, commitment, positive WOM, and negative WOM. Research design, data, and methodology - To empirically evaluate the proposed research model, this study was carried out using the survey with undergraduate students who were taking business courses. The 270 questionnaires were asked, and a total of 245 respondents provided complete and usable data. The sample consisted of 143 males(58.4%) and 102 females(41.6%). The variables of proposed model were measured on a 5-point Likert scale. The structural equation modeling analysis was used for the hypothesis test. Results - The overall fit of the model was acceptable(χ²=579.7(df=264, P=0.00), GFI=0.935, NFI=0.949, CFI=0.956, RMR=0.040). The results supported 6 hypotheses except for

and

. First, competence and benevolence were positively related to satisfaction, while integrity was not significant. A key result of the analysis was that benevolence has the strongest effect on satisfaction. Second, satisfaction had a positive impact on commitment and positive WOM but didn't significantly affect negative WOM. Third, commitment significantly enhanced positive WOM and reduced negative WOM. Conclusions - This study emphasizes the role of faculty trustworthiness based on a long-term relationship. And the findings suggest that the dimensions of faculty trustworthiness have differing effects on satisfaction. In particular, benevolence is found to be the most important factor. This study provides university managers with the following managerial implications. In order to increase the satisfaction of the students, university managers should focus on the faculty's competence and benevolence. Also, it is important that university managers take a relationship approach to maximize WOM effect.

• 한국추진공학회지
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• 제21권3호
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• pp.61-67
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• 2017

본 연구에서는 VOF 기법을 이용하여 3D 그레인 형상의 연소표면적을 계산하는 프로그램을 개발하고 연소표면적 결과를 이용하여 내탄도 성능해석을 수행하였다. 연소표면적 계산 수행 시 격자 크기, 난류화염속도, 단위 계산시간을 기초로 한 매개변수의 의존성을 확인하고, 상용 3D 모델링 소프트웨어를 이용하여 산출한 면적 결과와 비교하였다. 개발 프로그램으로 산출한 연소표면적 결과를 바탕으로 고체로켓모터의 내탄도 해석을 수행하였다. 임의의 추진제 조성으로 화학평형을 계산하고 시간에 따른 연소표면적 및 모터 내부 압력을 예측하였다. 웹(web) 연소 동안 평균 압력은 5.34 MPa 으로 기존 연구 결과와 약 20%의 차이를 보였다.

• 한국측량학회지
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• 제25권1호
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• pp.55-62
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• 2007

항공 라이다 데이터는 3차원 좌표로 표현된 점의 집합으로 대규모 지역의 지형측량을 신속하고 경제적으로 수행하여 고정밀의 수치지형모델을 제작하는데 사용된다. 특히 고정밀 수치지형모델 및 수치표고모델은 토목, 환경, 도시계획, 홍수모델 등에 있어서 정확한 예측과 분석을 가능하게 하며, 이로 인해 활용이 증가하고 있다. 항공 라이다 데이터로부터 수치지형모델을 제작하기 위해서는 건물, 식생 등과 같은 비지면점을 분류하고 제거하는 과정이 필요하다. 본 논문은 항공 라이다 데이터로부터 실세계를 구성하고 있는 지면점과 비지면점을 분류하는 필터링 방법을 제시하였다. 필더링 방법은 라이다 점 데이터를 높이 차이에 따라 분할하고, 분할된 점 데이터를 지면점과 비지면점으로 분류하는 과정으로 진행된다. 이러한 과정을 통해 건물, 식생 등과 같은 비지면점을 제거하고, 수치지형모델을 제작하기 위한 지면점을 추출하게 된다. 제시된 필터링 방법을 ISPRS의 Comparison of Filter(2003) 보고서에서 사용된 데이터에 적용하여 지면점과 비지면점의 분류 결과를 분석하였다.