• 대한전자공학회논문지TC
• /
• 제41권7호
• /
• pp.1-8
• /
• 2004

본 논문에서는 IEEE 802.11a OFDM(Orthogonal Frequency Division Multiplexing) 기반의 MIMO(Multiple Input Multiple Output) 시스템에서 별도의 피드백 채널 없이 ARQ(Automatic Repeat Request) 신호를 이용한 적응변조 기법을 제안한다. 제안한 기법은 일정수의 ACK(Acknowledgement)를 수신하면 이전 패킷의 변조단계로부터 변조 단계를 올리고 일정수의 NACK(Non-acknowledgement)를 수신하면 변조단계를 낮춤으로써 최적의 변조율을 추정하는 기술로 간단하고 빠른 수렴 속도를 갖는 장점이 있다. MIMO 시스템 기반의 본 논문에서는 모든 안테나의 전송률을 동일하게 조절하는 SRC(Same Rate Control)기법과 안테나별로 독립적으로 전송률을 조절하는 IRC(Individual Rate Control) 기법을 제안한다. 다양한 모의실험을 통하여 제안한 적응변조 기법들이 변조 방식이 고정된 기법뿐 아니라 기존의 ARQ를 이용하는 적응변조 기법에 비해서도 좋은 전송 효율을 나타냄을 확인하였다.

• 한국인터넷방송통신학회논문지
• /
• 제12권2호
• /
• pp.189-197
• /
• 2012

고수준의 명세나 고수준의 프로그래밍 언어로 작성된 원시 코드를 이용하여 테스트 데이터를 생성하는 것이 일반적이다. 그러나 어떤 상황에서는 이러한 테스트 데이터 생성 정보가 항상 이용가능하지 않을 수 있다. 이 논문에서는 실행가능 목적코드를 바탕으로 테스트 데이터를 생성하는 방법을 제안한다. 제안된 방법은 정교한 목적 코드 분석을 필요로 하지 않은 매우 간단한 함수 최소화 기법을 사용하여 동적으로 테스트 데이터를 생성한다. 삼각형 분류 프로그램에 대한 실험을 통하여 분기 커버리지를 매우 효과적으로 달성함을 보인다.

• Journal of Chest Surgery
• /
• 제29권10호
• /
• pp.1152-1156
• /
• 1996

총 대퇴동맥 거대동맥류는 드문 질환이며, 수술 시기를 놓치면 하지 절단을 초래하거나 사망할수도 있기 때문에 적절한 시기에 반드시 수술적 치료를 하여야 한다. 환자는 72세 남자로 입원 20일 전부터 생긴, 좌측 서혜부 박동성 종괴를 주소로 입원하였다 전산화 단층 촬영과 디 지탈 감쇄조영술로 총 대퇴동맥 거대동맥류를 진단하고 응급수술을 시행하였다. 수술은 동맥류를 절제하고 표재성 및 심부 대퇴동맥을 PTFE (Gore-tex) 인조혈관을 이용하여 연결하였다. 동맥류 원인은 병리 조직검사상 동맥 경화성으로 밝혀졌다.

• 대한기계학회논문집A
• /
• 제24권5호
• /
• pp.1314-1322
• /
• 2000

The acoustic property of reactive type single expansion chamber can be analyzed by traditional plane wave theory. This theory can be applied in low frequency range and has good performance. But this theory can't include higher order modes, therefore another method is essential to analyze acoustic filter in high frequency range. Many researcher suggested the method that can concern higher order modes, and their methods are using mode matching technique. But there is no method that can be applied to the analysis of single expansion chamber with arbitrary inlet/outlet duct position and numbers of higher order modes of inlet/outlet duct and middle chamber. In this paper, the method which can analyze single expansion chamber with arbitrary inlet/outlet duct position and numbers of higher order modes of inlet/outlet duct and middle chamber using fundamental mode matching technique, was suggested and the predictions by this method was compared with those by the finite element method, and the influence of inlet/outlet location to acoustic performance of single expansion chamber is investigated and explained by higher order mode effects.

• 대한기계학회논문집
• /
• 제16권12호
• /
• pp.2298-2305
• /
• 1992

본 연구에서는 보의 종방향 강성치를 실제보다 훨씬 작은 횡방향 강성치 수준 으로 낮추어 시간 적분을 수행하는 대신, 종방향에 작용하는 힘을 분산시켜서 계산시 종방향 상대 변형을 억제하는 기법을 사용하였다. 또 여러개의 물체가 조인트에서 서로 연결되어 이루어진 다물체 도역학의 해는 운동 방정식과 기구학적 제한조건을 모 두 만족시켜야 하며, 상미분 방정식 해법용 시간 적분을 바로 적용할 수는 없다. 본 논문에서는 참고문헌(13)과 (14)에 소개된 반복계산법 및 계산가속기법에 의하여 Lag- range multiplier를 운동 방정식에서 소거한 후 시간 적분을 수행하는 방법을 사용한 다.

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

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1995년도 제12회 음성통신 및 신호처리 워크샵 논문집 (SCAS 12권 1호)
• /
• pp.242-245
• /
• 1995

• 대한치과보철학회:학술대회논문집
• /
• 대한치과보철학회 2006년도 춘계학술대회 및 제3차 한일 공동 국제 학술대회
• /
• pp.118-118
• /
• 2006

• Restorative Dentistry and Endodontics
• /
• 제43권1호
• /
• pp.9.1-9.6
• /
• 2018

The objective of this case report is to introduce a simple technique for simultaneously taking a closed-mouth impression and functionally generated path (FGP) for a full coverage crown restoration. A monolithic zirconia crown was the restoration of choice. An alginate impression of the abutment tooth was taken to fabricate a custom-made closed-mouth impression tray covering the abutment tooth and the adjacent teeth. The tray had an FGP table and an abutment tray in cameo and intaglio surfaces, respectively. The impression was taken with silicone impression material after adjusting the abutment tray and inscribing the FGP using self-curing acrylic resins. Plaster casts were made from the impression, and a zirconia crown was fabricated. The crown was cemented to the abutment tooth with minimal adjustments. This simple technique resulted in a well-fitting crown that accounted for mandibular movements. Using the custom closed-mouth impression tray incorporating an FGP table simultaneously aids in fabricating an accurately fitting restoration that incorporates harmonious mandibular movements using a single impression capture.

• 대한방사선기술학회지:방사선기술과학
• /
• 제21권1호
• /
• pp.29-34
• /
• 1998

The purpose of simple abdomen erect projection is to see the fluid level which indicates gastrointestinal ileus or free air due to perforation. we do not have to insist on low kVp technique in simple abdomen erect position as long as we can detect the fluid level and free air shadow. Therefore, the author tried to decrease patient dose by high kVp technique and to improve the image quality due to motion artifact by reduction of exposure time. [Methods] Experiment 1. * screen/film SRO1000/HRH * exposure factor : $140\;kvp{\pm}5\;kv$ with added filters, 200 mA, 0.01 sec * phantom : Acryles : 15.0 cm(equivalent to 17 cm body thickness) 17.5 cm(equivalent to 21 cm body thickness) 20.0 cm (equivalent to 25 cm body thickness) With the exposure factor for same film density($D=0.8{\pm}0.1$) and with the materials above, we tried to find out entrance skin dose and gonad dose for both male and female. Experiment 2. Burger's phantom radiography were checked to see whether there was any change of image quality according to the kVp and the added filters. Experiment 3. Using rotating meter(self made), we examined the motion artifact and the exposure time limitation. [Results and conculution] 1. Using high voltage technique of 140 kVp with added filter, Skin dose, testicle dose and ovary dose decrease to 89.3%, 47% and 71.4% respectively compare to 70 kVp technique, 2. No great changes of Burger's phantom image has detected as from 70 kVp to 140 kVp and the air hole size of Burger's phantom over 0.028 cc(Diameter 3 mm, hight 4 mm) can be distinghished. 3. 0.01 sec(1 pulse) exposure time is possible in the single phase full wave rectification that why we can quitely reduce the unsharness caused by patient's movement.