• 한국전기전자재료학회논문지
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• 제36권2호
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• pp.136-142
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• 2023

In the past, the efficiency of solar cells had been increased in order to increase the efficiency of solar modules. However, in recent years, in order to increase output in the solar industry and market, the competitiveness of solar cells based on large-area solar cells and multi-bus bar has been increasing. Multi-busbar solar module is a technology to reduce power loss by increasing the number and width of the front busbar of the solar cell and reducing the current value delivered by the busbar by half through half-cutting. In the case of the existing M2 (156.75×156.75 mm²) solar cell, even with a half-cut, power loss could be sufficiently reduced, but as the area of the solar cell is enlarged to more than M6 (166×166 mm²), the need for more divisions emerged. This affected not only solar cells but also inverters required for module array configuration. Therefore, in this study, the electrical characteristics of a large-area solar cell and after division were extracted using Griddler simulation. The output characteristics of the module were predicted by applying the solar cell parameters after division to PSPice, and a guideline for the large-area solar module design was presented according to the number of divisions of the large-area solar cell.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.239-240
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• 2012

With advancements in semiconductor device technologies, manufacturing processes are getting more complex and it became more difficult to maintain tighter process control. As the number of processing step increased for fabricating complex chip structure, potential fault inducing factors are prevail and their allowable margins are continuously reduced. Therefore, one of the key to success in semiconductor manufacturing is highly accurate and fast fault detection and classification at each stage to reduce any undesired variation and identify the cause of the fault. Sensors in the equipment are used to monitor the state of the process. The idea is that whenever there is a fault in the process, it appears as some variation in the output from any of the sensors monitoring the process. These sensors may refer to information about pressure, RF power or gas flow and etc. in the equipment. By relating the data from these sensors to the process condition, any abnormality in the process can be identified, but it still holds some degree of certainty. Our hypothesis in this research is to capture the features of equipment condition data from healthy process library. We can use the health data as a reference for upcoming processes and this is made possible by mathematically modeling of the acquired data. In this work we demonstrate the use of recurrent neural network (RNN) has been used. RNN is a dynamic neural network that makes the output as a function of previous inputs. In our case we have etch equipment tool set data, consisting of 22 parameters and 9 runs. This data was first synchronized using the Dynamic Time Warping (DTW) algorithm. The synchronized data from the sensors in the form of time series is then provided to RNN which trains and restructures itself according to the input and then predicts a value, one step ahead in time, which depends on the past values of data. Eight runs of process data were used to train the network, while in order to check the performance of the network, one run was used as a test input. Next, a mean squared error based probability generating function was used to assign probability of fault in each parameter by comparing the predicted and actual values of the data. In the future we will make use of the Bayesian Networks to classify the detected faults. Bayesian Networks use directed acyclic graphs that relate different parameters through their conditional dependencies in order to find inference among them. The relationships between parameters from the data will be used to generate the structure of Bayesian Network and then posterior probability of different faults will be calculated using inference algorithms.

• 한국전산구조공학회논문집
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• 제30권4호
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• pp.329-334
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• 2017

다양한 산업 분야의 구조물은 여러 부구조의 조합으로 구성되며, 시스템의 자유도 또한 무수히 많다. 높은 복잡성을 가지는 구조물의 해석 및 계산 효율을 향상시키기 위해서 해석 모델의 단순화 및 자유도 축소가 요구된다. 지난 50여 년 동안 규모가 큰 공학적 문제를 단순화하기 위해 다양한 부분구조화 기법들이 개발되어 왔다. 이러한 부분구조화 기법들은 Newton-Raphson 알고리즘 등과 같은 반복계산을 동반하는 비선형 구조해석 문제 해석에 매우 효과적이다. 본 논문에서는 기 개발된 비선형 부분구조화 기법 중의 하나인 모드미분(modal derivatives)을 이용하여 기하비선형 보의 모델 축소에 적용하고자 한다. 모드미분은 모드 기반 축소 기저의 2차항의 형태로, 선형모드의 조합으로 근사 가능한 변위벡터를 미소변위에 대한 Taylor 급수를 통해 확인할 수 있으며, 시스템의 고유치 문제를 모드 좌표로 미분을 함으로써 얻어진다. 모드미분에는 비선형 접선 강성행렬의 미분을 포함하고 있으며, 이는 유한차분법 등의 근사를 통해 계산할 수 있다. 제안된 방법론은 기하학적 비선형 문제에 우수한 성능을 보이는 동시회전 유한요소법에 적용하였다. 수치예제를 통해 보의 경계가 수평으로 움직일 수 있는 문제에서는 기존의 모드축소기법이 매우 비효율적임을 알 수 있었다. 한편 모드미분을 이용한 축소기법은 다양한 경계조건에 대하여 우수한 성능을 보임을 확인하였다.

• 한국환경과학회지
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• 제19권5호
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• pp.591-605
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• 2010

This study were to simulate major criteria air pollutants and estimate regional source-receptor relationship using air quality prediction model (TAPM ; The Air Pollution Model) in the Seoul Metropolitan area. Source-receptor relationship was estimated by contribution of each region to other regions and region itself through dividing the Seoul metropolitan area into five regions. According to administrative boundary, region I and region II were Seoul and Incheon in order. Gyeonggi was divided into three regions by directions like southern(region III), northern(IV) and eastern(V) area. Gridded emissions ($1km{\times}1km$) by Clean Air Pollicy Support System (CAPSS) of National Institute of Environmental Research (NIER) was prepared for TAPM simulation. The operational weather prediction system, Regional Data Assimilation and Prediction System (RDAPS) operated by the Korean Meteorology Administration (KMA) was used for the regional weather forecasting with 30km grid resolution. Modeling period was 5 continuous days for each season with non-precipitation. The results showed that region I was the most air-polluted area and it was 3~4 times more polluted region than other regions for $NO_2$, $SO_2$ and PM10. Contributions of $SO_2$ $NO_2$ and PM10 to region I, II and III were more than 50 percent for their own sources. However region IV and V were mostly affected by sources of region I, II and III. When emissions of all regions were assumed to reduce 10 and 20 percent separately, air pollution of each region was reduced linearly and the contributions of reduction scenario were similar to those of base case. As input emissions were reduced according to different ratio - region I 40 percent, region II and III 20 percent, region IV and V 10 percent, air pollutions of region I and III were decreased remarkably. The contributions to region I, II, III were also reduced for their own sources. However, region I, II and III affected more regions IV and V. Shortly, graded reduction of emission could be more effective to control air pollution in emission imbalanced area.

• 한국전산구조공학회논문집
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• 제22권1호
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• pp.73-79
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• 2009

본 논문에서는 승객 보호용으로 지하철 역사에 설치된 PSD(승강장 스크린 도어)의 상부 헤더박스 내에 부착되어 개폐용 유리문을 지지하는 알루미늄 구동(레일)부재에 대한 구조해석과 최적설계를 수행하였다. 구동부재의 볼트 체결부에 대한 엄밀한 구조해석을 위하여 물리적 현상과 일치하도록 상세 유한요소 모델링하여 해석의 정확도를 높였다. 또한 유리문이 구동부재에 걸려 있으면서 개폐될 때 발생하는 하중의 이동상태를 고려한 구조해석 결과, 설계 목표치인 내구 수명 20년이 만족되었다. 구동부재 단면의 단면 길이를 설계변수로 하고 설계제약조건(응력의 최소화, 중량의 감소)에 만족할 수 있도록 반응표면법을 적용한 최적화를 수행하여 15%의 감량 결과를 도출하였다.

• Coupled systems mechanics
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• 제9권4호
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• pp.359-379
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• 2020

Due to susceptibility of bridges in the past earthquakes, vulnerability assessment and strengthening of bridges has gained a particular significance. The objective of the present study is to employ an analytical method for the development of fragility curves, as well as to investigate the effect of strengthening on the RC box-girder bridges. Since fragility curves are used for pre-and post-earthquake planning, this paper has attempted to adopt the most reliable modeling assumptions in order to increase the reliability. Furthermore, to acknowledge the interaction of soil, abutment and pile, the effect of different strengthening methods, such as using steel jacketing and FRP layers, the effect of increase in the bridge pier diameter, and the effect of vertical component of earthquake on the vulnerability of bridges in this study, a three-span RC box-girder bridge was modeled in 9 different cases. Nonlinear dynamic analyses were carried out on the studied bridges subjected to 100 ground motion records via OpenSEES platform. Therefore, the fragility curves were plotted and compared in the four damage states. The results revealed that once the interaction of soil and abutment and the vertical component of the earthquake are accounted for in the calculations, the median fragility is reduced, implying that the bridge becomes more vulnerable. It was also confirmed that steel jackets and FRP layers are suitable methods for pier strengthening which reduces the vulnerability of the bridge.

• 대한전자공학회논문지TC
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• 제44권2호
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• pp.1-5
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• 2007

파장분할다중화방식(WDM - Wavelength Division Multiplexing) 네트워크는 차세대 전송망으로서 주목받고 있다. WDM네트워크는 IP, SONET, ATM 과 같은 클라이언트층에 광경로를 통한 circuit-switching을 제공함으로해서 전송속도의 향상, 트래픽 패턴에 따른 토폴로지 재구성등을 가능하게 한다. 광경로들의 집합으로서 가상 토폴로지가 정의되는데, 각각의 광경로를 정의하는 광학 스위치들이 재구성 가능하기 때문에, 가상 토폴로지도 재구성 가능하게 된다. 이러한 WDM 네트워크의 특징은 클라이언트 층이 요구하는 트래픽 패턴에 따라 가상 토폴로지를 재구성함으로서 네트워크 성능을 최적화 시킬 수 있게 한다. 본 논문에서는 시간에 따라 변화하는 트래픽 패턴 하에서 가상 토폴로지를 재구성하면서, 각 광경로의 트래픽에 대한 로드벨런싱을 하는 기법을 제시한다. 이 기법은 기존의 기법들과는 달리 미래의 트래픽 패턴을 알고 있다는 가정을 필요로 하지않는다. 제안된 기법의 성능을 평가하기 위해 시뮬레이션을 수행하였으며, 시뮬레이션을 위하여 실제 백본 네트워크에서의 트래픽율의 측정을 통한 트래픽 모델링을 하였다. 제안된 기법과 이전 기법과의 광경로에 대한 표준편차의 비교를 통해, 제안된 기법이 이전 기법보다 로드벨런싱에 있어 성능향상을 보여준다는 것을 알 수 있었다.

• 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.