• 한국음향학회지
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• 제18권4호
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• pp.23-30
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• 1999

본 연구에서는 통과대역폭, 리플, 저지대역 감쇠도의 필터특성을 고려하여 주어진 입력사양에 부합하는 withdrawal SAW 필터의 새로운 최적화 알고리즘을 개발하고자 하였다. 필터의 성능해석을 위해 델타함수 모델을 이용하였으며, 대표적인 필터구조로서 균일한 입력 IDT에 대해 출력단을 withdrawal weighting하는 경우를 선정, 해석하였다. 이를 위해 여덟개의 설계변수를 선정하였으며 각각의 변화가 성능변수에 미치는 영향을 고려하여 세 단계를 거쳐 최적화 알고리즘을 완성하였다. 첫 단계에서는 삽입손실을 고려하여 입출력 전극수와 형상의 규격을 결정하고 다음 단계에서는 위상반전 방법을 이용하여 대역폭을 조절하며, 마지막 단계에서는 전극을 추가, 제거하는 방법을 통해 저지대역의 특성규격을 만족시켰다. 본 연구를 통해 제시하는 새로운 withdrawal weighting 필터 설계방법은 기존의 설계 방법들과는 달리 통과대역폭, 리플. 저지대역 억압도, 삽입손실 등의 필터특성을 동시에 고려하며 주어진 입력사양에 부합하는 필터를 최적화할 수 있다.

• Archives of Plastic Surgery
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• 제46권2호
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• pp.129-134
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• 2019

Background Nipple-areolar complex (NAC) reconstruction is the final stage of breast reconstruction. Ideal reconstruction of the NAC requires symmetry in position, size, shape, texture, pigmentation, and permanent projection, and although many technical descriptions of NAC reconstruction exist in the medical literature, there is no gold standard technique. The technique devised by the authors is very versatile, with excellent results, and it enables 1-step reconstruction with optimal results in terms of shape and nipple projection. Methods Our technique consists of a combination of modified local flaps and a full-thickness skin graft. Patients were observed for 18 months to estimate the amount of retraction. This procedure was performed in 40 patients, four of them bilaterally. The duration of the follow-up was 30 months. Complications occurred in 10% of patients, and included infections (5%), ischemia (2.5%), and hematoma (2.5%). Results No cases of total nipple necrosis were reported. The NAC shape remained optimal in all cases, with a very small reduction of the vertical and horizontal diameters of the areola, which maintained its designed round shape well, and negligible retraction in the diameter and projection of the nipple. Conclusions The oval technique represents a major step forward, involving a combination of existing techniques, such as the C-V flap and the cutaneous graft, to achieve excellent results regarding areola shape and nipple projection, significantly reducing the cases of nipple ischemia. These results were substantially obtained through subcutaneous equatorial sutures, skin grafting, and flattening of the apexes of the flap.

• 한국정보통신학회논문지
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• 제14권9호
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• pp.2143-2149
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• 2010

본 논문에서는 지리정보 라우팅 프로토콜 중 가장 잘 알려진 GPSR의 성능을 향상시키기 위한 에이전트 기반의 로드 분산 알고리즘을 제안한다. 제안된 방법은 싱크 노드 주변 노드 중에 하나를 에이전트 노드로 설정하고 데이터 패킷을 싱크로 직접 전송하는 대신에 에이전트 노드에게 전송하고 이 패킷들은 에이전트 노드에 의하여 싱크로 전달되게 하게 함으로써 트래픽의 분산을 자동적으로 유도한다. 또한, 데이터 포워딩시에는 위치 정보뿐만 아니라 주변 노드의 현재 버퍼 사용량을 기준으로 다음 홉을 선택하게 함으로써 혼잡을 효율적으로 예방함으로써 로드 분산을 수행한다. 이러한 기능들은 패킷의 손실의 줄이게 되고 결국 패킷 전송 성공률이 높아지게 된다. 제안된 메커니즘의 성능 평가를 위하여 싱크노드로의 연결 수와 홉 수에 따른 패킷 전송 성공율을 측정한 결과 기존 GPSR 프로토콜에 비하여 향상된 성능을 확인하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.51-54
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• 2007

The purpose of this paper is the development of measurement algorithm for green-sheet based on the digital image processing technique. The Low Temperature Cofired Ceramic (LTCC) technology can be defined as a way to produce multilayer circuits with the help of single tapes, which are used to apply conductive, dielectric and / or resistive pastes on. These single green-sheets have to be laminated together and fired in one step all. Main functionality of the green-sheet film measurement algorithm is to measure the position and size of the punching hole in each single layer. The line scan camera coupled with motorized X-Y stage is used for developing the algorithm. In order to measure the entire film area using several scanning steps, the overlapping method is used. In the process of development of the algorithm based on the image processing and analysis, strong background technology and know-how have been accumulated.

• 전력전자학회논문지
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• 제18권4호
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• pp.376-386
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• 2013

This paper proposes an improved Maximum Power Point Tracking method and design methods of unmanned solar vehicle system by parts of hardware, unmanned driving control and power conversion. The hardware design is offered on the weight reduction and structural reliability by using structural analysis software. The technique of curve fitting is applied to unmanned control system due to minimizing the vehicle's behavior. Furthermore, lateral controller applying actuator dynamics is robust enough to prevent performance degradation by measurement noise regarding position and heading angle. The power conversion system contains battery charger system and tapped-inductor boost converter. In the battery charger system, variable step-size MPPT is conducted for quick response of maximum power point tracking. The validity of the proposed algorithm are verified by simulations and experiments.

• 한국광학회지
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• 제10권5호
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• pp.364-368
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• 1999

일반적으로 LSU(Laser Scanning Unit)는 LD모듈(Laser Diode, 콜리메이팅 렌즈, 슬릿), 실린더 렌즈 고속회전하는 PM(Polygon Mirror), f$\theta$렌즈와 같은 광부품들과 이들을 취부하는 Housing으로 구성되어져 있다. 먼저 본 논문에서는 당사에서 자체적으로 광설계된 LSU 시작품(시작(試作品)을 측정/평가하기 위해 평가항목들에 관해 살펴 보았다. 당사에서 시제작된 LSU의 특징은 LSU의 핵심부품인 f$\theta$렌즈가 2단가압형 저압사출방식으로 제작되었다는 것이다. LSU의 평가항목들은 BSH(Beam Scan Head)를 LMC(Linear Motion Controller)위에 장착해서 비교적 간단히 측정 할 수 있었고, 측정결과 600DPI(Dots Per Inch) 성능을 만족함을 확인할 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1256-1259
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• 2002

In this paper, we have proposed license plate recognition system for multi-national vehicle license plate using geometric features along with hybrid and seven segment pattern vectors. In the proposed system, we suggested to find horizontal and vertical relation after going through preparation process with inputted real-time license plate image of Korea and Japan, and then to classify license plate with using characteristic and geometric information of license plates. It classifies the extracted license plate images into letters and numbers, such as local name, local number, classification character and license consecutive numbers, and recognize license plate of Korea and Japan by applying hybrid and seven segments pattern vectors to classified letter and number region. License plate extraction step of the proposed system uses width and length information along with relative rate of Korean and Japanese license plate. Moreover, it exactly segmentation by letters with using each letter and number position information within license plate region, and recognizes Korean and Japanese license plates by applying hybrid and seven segment pattern vectors, containing characteristics related to letter size and movement within segmented letter area. As the result of testing the proposed system in real experiment, it recognized regardless of external lighting conditions as well as classifying license plates by nations, Korea and Japan. We have developed a system, recognizing regardless of inputted structural character of vehicle licenses and external environment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.71-73
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• 1995

For the accurate analysis of induction motors driven by PWM-type inverter, a time-stepping finite element method is presented in this paper. Since the PWM-type source voltage is not sinusoidal, the time harmonic method can not be used. Therefore, we used a time-stepping method, where the space harmonics due to the slot structure can be analyzed and each time-step size is determined from each increase of rotor position. As a numerical example, an induction motor of 20 Hp, 3 phase and 6 pole is analyzed. First, numerical results of the time-stepping finite element analysis are compared to those of conventional equivated circuit analysts. Next, the stator current characteristic obtained from PWM voltage source is compared to that from sinusoidal voltage source.

• Archives of Plastic Surgery
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• 제48권2호
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• pp.179-184
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• 2021

Women attach great importance to the presence of a three-dimensional nipple upon completion of the breast reconstruction process. To meet patients' expectations, nipple-areolar complex reconstruction should achieve symmetry in position, size, shape, texture, and color, as well as minimizing donor-site morbidity. However, it is well known that regardless of the reconstructive technique, loss of nipple projection can be reasonably expected. We developed and evaluated a quick, simple, and innovative technique using injectable Integra Flowable Wound Matrix to increase nipple projection after reconstruction. Twenty breast cancer patients who underwent nipple reconstruction resulting in unsatisfactory projection were enrolled in our retrospective study. Nipple projection was measured at the time of surgery and after 6 and 12 months. A visual analogue scale was used to assess patients' satisfaction. Our technique yielded reliable results in terms of the long-lasting maintenance of nipple projection. This method is high-priced, but cost-effective, since one kit may suffice for three patients. Furthermore, our patients were very appreciative of this technique as a single-step, minimally invasive, painless procedure with no reported necessity of re-intervention.

• 한국정보통신학회논문지
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• 제7권3호
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• pp.568-576
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• 2003

본 논문에서는 계층적 탐색기법을 이용한 동적 배경에서의 이동물체 추적 알고리즘을 제안하였다. 제안한 알고리즘은 초기모델 생성단계와 이동물체 추적 단계로 구성되었으며, 이전프레임에 비해 이동 거리가 큰 경우에도 안정적으로 추적할 수 있었다. 그리고, 카메라의 흔들림과 추적물체의 3차원 운동으로 인한 형태 변화에도 전체 프레임에서 효과적으로 추적을 할 수 있었고, 이동물체의 정확한 위치를 검출하여 추적시간을 단축할 수 있었다. 정합모델과 윤곽선 영상에 사이에 이동물체의 유사도 판정은 Partial Hausdorff 거리를 이용하여 평가하였다. 제안한 알고리즘의 타당성 검토를 위해 도로에서 주행하는 차량을 대상으로 이동물체 검출 및 추적 실험을 한 결과 정합횟수는 평균 28.21회이고, 프레임 당 정합시간은 평균 53.21 ms로 제안한 알고리즘의 우수성을 입증하였다. 추적위치와 실체위치를 비교하여 그 평균 자승오차를 계산한 결과 E=1.148임을 알 수 있었다. 차량의 크기, 색상 및 형태가 다른 경우 도로의 색과 차이가 있는 차량들은 98.66%의 추적 성능을 나타냈으며, 검정색 또는 적색 등과 같은 차량은 흑백 영상에서 도로의 색과 유사하여 배경의 영향을 많이 받으므로 95.33%이었고, 전체 평균은 97%로 우수한 추적 성능을 나타내었다.