• 대한치과보철학회지
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• 제29권1호
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• pp.73-89
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• 1991

Impression ragistration is an improtant and difficult phase of prosthodontic treatment procedures and a tray of appropriate size and shape is essential to obtain the accurate impression. Particularly, in edentulous patients, the size and forms of their residual alveolar ridges are different from one another. Therefore, in this study, various measurements were taken on the edentulous models. And the measurements were analyzed and compared with one another. The results were as follows ; 1. The mean of denture bearing area was $32.86cm^2$ in the upper jaws, $24.20cm^2$ in the lower jaws and the variation of denture bearing area was greater in the upper than in the lower jaws and in males than in females. 2. The mean of A-P(anteroposterior) ridge length was 48.72mm in the upper jaws, 53.05mm in the lower jaws and that of males was longer than that of females. 3. The mean of most posterior ridge width was 47.23mm in the upper jaws, 58.03mm in the lower jaws and the difference of that between males and females was least in both jaws. 4. In the upper jaws, the mean of ridge width was 29.66mm on anterior 1/4, 42.79mm on middle, 48.95mm on posterior 1/4 line and the mean of palatal height was 4.56mm on anterior 1/4, 10.01mm on middle, 10.84mm on posterior 1/4 line. 5. In the lower jaws, the mean of ridge width was 33.24mm on anterior 1/4, 50.19mm on middle, 59.16mm on posterior 1/4 line and the mean of lingual ridge height was 5.49mm on anterior 1/4, 9.16mm on middle, 16.72mm on posterior 1/4 line. 6. The correlation coefficient(=r) between denture bearing area and A-P ridge length was 0.83 in the upper jaws and 0.75 in the lower jaws. The corelation between denture bearing area and AP ridge length was statistically significant, but, between denture bearing area and A-P ridge length and between A-P ridge length and the most posterior ridge width was not statistically significant in both jaws. 7. Alveolar ridge forms were classified into three(ovoid, "u" shape, and "v"shape) categories. In the upper jaws, ovoid was 66%, "u" shape was 24%, and "v" shape was 10%, in the lower jaws, ovoid was 66.7%, "u" shape was 20%, and "v" shape was 13.3%.

• 한국전자통신학회논문지
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• 제19권1호
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• pp.19-24
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• 2024

본 논문에서는 기존의 접힌 도파관의 내부 구조물을 Y형으로 대체하여 도파관의 차단주파수를 낮춘 접힌 Ridge 도파관(FRWG)을 제안하였다. 제안된 FRWG는 역 Ridge 도파관으로 등가될 수 있는데, 측면의 높이를 줄였을 때 측면의 길이가 증가하여 동일한 크기의 도파관에 비해 차단주파수를 절반 이하로 줄일 수 있다. 논문에서는 길이 40mm, 높이 20mm의 도파관에 폭 2mm의 Y형 구조물을 넣어 1.996GHz의 차단주파수를 갖는 FRWG를 설계하였다. 또한, 제안된 도파관을 활용하기 위한 SMA 커넥터와의 트랜지션이 설계되었다. 트랜지션은 커넥터의 신호선과의 커패시턴스를 최적화하여 2.064 ~ 3.050GHz 대역에서 VSWR 2:1 이하의 특성을 나타내었다. 제안된 FRWG는 도파관 구조를 이용한 다양한 소자의 소형화에 응용할 수 있다.

• 융합신호처리학회논문지
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• 제6권2호
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• pp.67-73
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• 2005

최근 개인인증 기술에 대한 요구가 증가하고 있다. 지문인식은 이 요구에 대응하여 광범위하게 사용되고 있는 생체인식 기법중의 하나이다. 본 연구에서는 특징점의 융선형태 정보를 이용한 지문매칭 알고리즘을 제시한다. 여기서 융선형태는 1차원 이산신호로 표현되어 사용된다. 본 알고리즘은 다음의 절차로 처리된다. 먼저, 입력지문과 등록지문의 모든 특징점에서 융선을 1차원 이산신호로 표현하여 융선형태 정보를 얻는다. 그리고 두 지문에서 유사한 융선형태를 갖는 특징점쌍을 구한 후 이로부터 두 지문의 회전각도와 이동변위의 후보를 구한다. 이 후보들로부터 군집화 기법을 통해 최종적인 회전각도와 이동변위를 얻어 입력지문에 대해 정렬을 수행한다. 마지막으로 정렬된 입력지문과 등록지문사이에 일치되는 특징점쌍을 찾아 매칭률을 계산한다. 실험결과 $0.79\%$의 FAR에서 $18.0\%$의 FRR를 달성하였다.

• 대한치과의사협회지
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• 제57권12호
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• pp.768-777
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• 2019

Alveolar bone resorption are unpredictable and always occur after tooth extraction. Such bone resorption causes insufficient alveolar ridge which make implant placement difficult. There are many techniques to increase the alveolar ridge. Representative procedures include ridge split, guided bone regeneration, bone graft using autogenous block bone, and alveolar distraction. In each procedure, there are indications and complications. Depending on the shape and the width of bone defects, we can choose procedures for horizontal bone augmentation and vertical bone augmentation.

• 한국항해학회지
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• 제22권4호
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• pp.37-44
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• 1998

This paper presents a procedure for automated extraction of ridge shadows in noisy gray images. This procedure mainly consists of 1) a deformable model which is designed basing upon the knowledge about the shape of shadows and is expected to be useful in extracting ridge shadows especially located in low signal to noise ratio background, and 2) the scale space scheme which is also useful even if there is less information about the size and the positions of ridge shadows in advance. This procedure is applied to artificial images and its performance is evaluated experimentally.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.100-100
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• 2022

This study was conducted in 2021 using Kwangpyeongok and Gangdaok, that showed good yield performance both under upland and lowland conditions in the previous year. The experiments were carried out by sowing on April 22, May 14, May 30, June 19, and July 10, with aim to determine optimum sowing date in central region of Korea. The growing degree days (GDD) required to read the flowering stage were 1375.5-1725.3℃ for upland and 1582.7-1982.4℃ for lowland condition. The lowest GDD was observed in July 10 sowing regardless of ridge formation both under lowland and upland conditions for Kwangpyeongok. However, Gangdaok showed the lowest GDD under no-ridge in lowland and high-ridge in upland, both of which were sown on June 19. The difference in GDD between no-ridge and high-ridge treatment was little depending on the sowing date. In both lowland and upland, there was no significant difference between no-ridge and high-ridge treatments in stover dry matter, ear dry matter, and TDN between no-ridge and high-ridge treatments. Under upland condition, no significant difference in biomass and TDN was observed among sowing date treatments and between varieties. Under lowland condition, biomass production was severely reduced in May 30 sowing treatment, whereas no varietal difference was observed. Reduced biomass in May 30 sowing treatment may be due to excess waterlogging and lodging by rainfall.

• Journal of the korean society of oceanography
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• 제32권4호
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• pp.181-190
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• 1997

A large subtidal sand ridge (Jungang Satoe) in Asan Bay, on the west coast of Korea, was studied in order to understand the morphology and sediment transport trend in a macrotidal setting, by means of analyzing sediment samples, current data, side-scan sonographs and seismic profiles. The ridge is about 15 km long and 2-5 km wide, with a relief of about 15 m. It is elongated in the flow direction of flood (SE) and ebb (NW) tidal currents, but asymmetrical in cross section. The western and southwestern side of the ridge is characterized by relatively gentle slopes averaging 0.4$^{\circ}$, whereas on the northeastern side, relatively steep slopes were mapped with 1.6$^{\circ}$ slope angles. Tidal currents associated with the ridge are very strong; maximum surface velo-cities range from neap values of 50 cm/s to spring values of 130 cm/s. The shear velocities during flood and ebb are strong enough to erode and transport sands on the ridge. Sand waves and megaripples (dunes) are the most common bedforms produced by the tidal currents, which show regional differences in shape and size on the ridge. The distribution pattern of these bedforms in-dicates that the flood tidal currents are dominant on the offshore (northwest) side of the ridge, whereas the onsho.e (southeast) side of the ridge is ebb-dominated. The sand transport path as inferred from bedform orientations is directed toward the ridge crest on the flanks, whereas on the crest, it is near-longitudinal to the ridge axis. The convergent, upslope movement of sands on the ridge flanks appears to be important in sand ridge building and maintenance. A significant ridge migration toward the northeast can be suspected on the basis of the ridge morphology, which may cause offshore hazards for navigation.

• 한국해양공학회지
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• 제16권1호
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• pp.27-35
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• 2002

The interaction of grounded ice ridges with underlying seabed is one of the major considerations in the design of Arctic pipeline system. Previously several ice scour models were developed by researchers to describe the ice scour-seabed interaction mechanism. In view of possible improvements, a comparative study of those ice scour models is performed and their limitation in modeling is discussed. Simple laboratory tests are carried out and then the shape pattern of deposited soil around the ice model is newly defined. Unlike the rectangular idealization of an ice block, in this modified ice scour model, trapezoidal cross sections are assumed to represent the typical shape of an ice ridge based on the field observation data. With the horizontal and vertical motion of ice model, the ice scour depth and soil reacting forces on seabed are calculated with varying the keel angle of an ice ridge.

• 한국해양학회지
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• 제29권3호
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• pp.278-286
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• 1994

서해 경기만은 조류방향과 대체로 일치하는 조류성사퇴가 해저면에 발달하고 있으 며, 또 하나의 사퇴구조가 탄성과 퇴적단위내에 매몰되어 나타난다. 이돌 사퇴의 발생 기원과 퇴적환경규명을 위해 팔미도 부근의 사퇴해역에서 획득된 고해상도 탄성피자 료, 표층퇴적물, 주상퇴적물에 대한 정밀 분석 및 연구가 실시되었다. 팔미도 부근의 사퇴 발달해역은 3개의 탄성과 퇴적단위로 구분되며 (unit A, B, C), 각 퇴적단위내에 는 각각 하나의 사퇴가 나타난다(ridge A, B, C). 최상부 퇴적단위내의 사퇴 A 는 조 류방향과 대체로 평행한 북동-남서방향으로 발달하고 있으며 (41$^{\circ}$), 남동방향을 향하 는 사층리 반사구조가 나타난다. 이는 사퇴가 점차 남쪽방향으로 이동되고 있음을 시 사하고 있다. 퇴적단위 B는 하나의 사퇴(ridge B)와 수로충진 구조로 이루어져 있으 며, 사퇴 A와 비교할 때 대체로 유사한 방향, 규모, 내부구조 등을 보이고 있다. 이러 한 사실은 퇴적단위 B가 현재보다 수심의 약 10 m 낮았던 시기에 현재와 유사한 환경 에서 사질퇴적물의 이동에 의해 사퇴 B가 형성되었으며, 해수면이 상승하면서 세립질 퇴적물이 사퇴의 골짜기에 퇴적되어, 수로와 유사한 형태 또는 수평층리된 형태의 수 로충진구조를 나타내는 것으로 해석된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.628-631
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• 1988

This paper describes a fingerprint classification on the basis of feature points(whorl, core) and feature vector and uses a syntactic approach to identify the shape of flow line around the core. Fingerprint image is divided into 8 by 8 subregions and fingerprint region is separated from background. For each subregion of fingerprint region, the dominant ridge direction is obtained to use the slit window quantized in 8 direction and relaxation is performed to correct ridge direction code. Feature points(whorl, core, delta) are found from the ridge direction code. First classification procedure divides the types of fingerprint into 4 class based on whorl and cores. The shape of flow line around the core is obtained by tracing for the fingerprint which has one core or two core and is represented as string. If the string is acceptable by LR(1) parser, feature vector is obtained from feature points(whorl, core, delta) and the shape of flow line around the core. Feature vector is used hierarchically and linearly to classify fingerprint again. The experiment resulted in 97.3 percentages of sucessful classification for 71 fingerprint impressions.