• International Journal of CAD/CAM
• /
• 제4권1호
• /
• pp.33-45
• /
• 2004

In this work, a rational procedure has been formulated for the selection of points approximating slice contours cut in LOM (Laminated Object manufacturing) with first order approximation. It is suggested that the number of points representing a slice contour can be 'minimised' or 'optmised' by equating the horizontal chordal deviation (HCD) to the user-defined surface form tolerance. It has been shown that such optimization leads to substantial reduction in slice height calculations and NC codes file size for cutting out the slices. Due to optimization, the number of contour points varies from layer to layer, so that points on successive layer contours have to be matched by four sided ruled surface patches and triangular patches. The technological problems associated with the cutting out of triangular patches have been addressed. A robust algorithm has been developed for the determination of slice height for optimum and arbitrary numbers of contour points with different strategies for error calculations. It has been shown that optimisation may even lead to detection and appropriate representation of elusive surface features. An index of optimisation has been defined and calculations of the same have been tabulated.

• 대한전자공학회논문지SP
• /
• 제49권2호
• /
• pp.8-17
• /
• 2012

본 논문에서는 박막의 삼차원 형상을 신속하게 획득하기 위한 새로운 방법을 제안한다. 기존의 반사광 측정 장치에 기반한 박막 측정 장비들은 170포인트에 대한 두께를 측정하는데 약 30분 이상의 시간이 요구되므로 박막의 전체적인 형상 정보를 신속하게 파악하는데 적합하지 않다. 제안하는 방법은 Canny 경계검출기를 이용하여 간섭무늬 영상으로부터 등고선을 검출하는 영상 분석법을 기반으로 한다. 검출된 등고선에 대한 절대적인 두께를 측정하고 Borgefors 거리변환 알고리즘을 이용한 보간 처리를 통해 등고선으로부터 높이 맵 정보를 추출한다. 추출된 높이 맵은 DirectX를 사용하여 높이 맵 지형처리 기법으로 삼차원 형상화 된다. 제안된 방법은 적은 수를 가지는 등고선에 대한 높이 정보만을 실측하게 되므로 약 5분의 수행시간으로 박막의 전반적인 삼차원두께 패턴 정보를 얻을 수 있다.

• 대한한의학회지
• /
• 제23권3호
• /
• pp.1-10
• /
• 2002

Objective: There exist gender differences in pulsatile contour waveform. Women have a greater age-related increase in left ventricular mass than do men and more likely to experience symptomatic heart failure after infarction. SDPTG (the second derivative of photoplethysmogram waveform) is a noninvasive method for evaluating the pulse wave and is correlated with age and other risk factors for atherosclerosis. We studied the effect of gender on SDPTG and made clear why the gender differences appear. Methods: To study the effects of effect factors, including height and blood pressure, on SDPTG in the fourth decade, data on height, weight, PTD (pulse transit distance), blood pressure, serum lipid levels, and SDPTG were collected in 115 laboratory healthy men and women. SDPTG is derived from double-differential processing of fingertip photoplethysmography and consists of a, b, c, and d waves in systole and an e wave in diastole; SDPTG aging index (AI) was calculated as (b-c-d-e)/a. Results: There were significant gender-related differences of SDPTG AI, height, and blood pressure. Age, height, and mean blood pressure were respectively and significantly correlated with SDPTG AI. SDPTG is dependent upon age, height, and blood pressure. Restricting analysis to SDPTG AI, age, height, and mean blood pressure, yielded that there were gender-related differences in SDPTG AI (P<0.05) which were derived from those of height (F<0.001, df=l, P=0.994). Conclusions: These new data may help to explain previous findings about age-related differences in pulsatile contour waveforms and why gender differences of SDPTG appear. The results of this study suggest that SDPTG AI, used for evaluation of biological vascular aging, should be calibrated by height as well as age and blood pressure.

• Wind and Structures
• /
• 제38권6호
• /
• pp.445-459
• /
• 2024

To model the aeroelasticity in vortex-induced vibrations (VIV) of slender tubular towers, this paper presents an approach where the aerodynamic damping distribution along the height of the structure is calculated not only as a function of the normalized lateral oscillation but also considering the local incoming wind velocity ratio to the critical velocity (velocity ratio). The three-dimensionality of aerodynamic damping depending on the tower's displacement and the velocity ratio has been observed in recent studies. A contour map model of aerodynamic damping is generated based on the forced vibration tests. A sectional calculation procedure based on the spectral method is developed by defining the aerodynamic damping locally at each increment of height. The proposed contour map model of aerodynamic damping and the sectional calculation procedure are validated with full-scale measurement data sets of a rotorless wind turbine tower, where good agreement between the prediction and measured values is obtained. The prediction of cross-wind response of the wind turbine tower is performed over a range of wind speeds which allows the estimation of resulting fatigue damage. The proposed model gives more realistic prediction in comparison to the approach included in current standards.

• 제어로봇시스템학회논문지
• /
• 제22권11호
• /
• pp.932-936
• /
• 2016

In this paper, we present a method for the inspection of diamond wheels. In total, six items, including height, radius, and angle, need to be checked during the manufacturing of a diamond wheel. Automatic inspection through image processing is presented in this paper. First, a contour corresponding to the boundary of the diamond wheel is extracted from an image. Next, control points are selected by processing the contour. Seven control points are detected and used for the computation of the required item. Detailed procedures for the computation of the height, radius, and angle using control points are presented in this paper. Experimental results show the feasibility of the presented method.

• 한국어교육
• /
• 제28권3호
• /
• pp.25-51
• /
• 2017

This study aimed to identify the differences in pitch perception between tonal and non-tonal language listeners. A total of 60 Korean and Chinese listeners participated in the perception test. A two-syllable nonsense word /paba/ was manipulated in five steps. The pitch height or contour on the second syllable was raised or lowered. Both groups were asked to select which of the two syllables had the higher pitch. The findings showed that the majority of Korean listeners (GK) perceived decreased pitch as each peak of the syllable was lowered and perceived increased pitch as it was raised, which means the pitch height is a primary perceptual cue for GK. However, Chinese listeners (GC) perceived sensitive pitch movements as the pitch contour changed. GC's perception may presumably be affected by the L1's tone sandhi. We found it reasonable to assume that language experience has a significant effect on the cross-linguistic perceptual differences between tone and non-tonal language listeners.

• Journal of Periodontal and Implant Science
• /
• 제54권2호
• /
• pp.108-121
• /
• 2024

Purpose: The aim of this study was to compare changes in soft and hard tissue and the histologic composition following early implant placement in sites with alveolar ridge preservation or spontaneous healing (SH), as well as implant performance up to 1 year after crown insertion. Methods: Thirty-five patients with either intact buccal bone plates or dehiscence of up to 50% following single-tooth extraction of incisors, canines, or premolars were included in the study. They were randomly assigned to undergo one of three procedures: deproteinized bovine bone mineral with 10% collagen (DBBM-C) covered by a collagen matrix (DBBM-C/CM), DBBM-C alone, or SH. At 8 weeks, implant placement was carried out, and cone-beam computed tomography scans and impressions were obtained for profilometric analysis. Patients were followed up after the final crown insertion and again at 1 year post-procedure. Results: Within the first 8 weeks following tooth extraction, the median height of the buccal soft tissue contour changed by -2.11 mm for the DBBM-C/CM group, -1.62 mm for the DBBM-C group, and -1.93 mm for the SH group. The corresponding height of the buccal mineralized tissue changed by -0.27 mm for the DBBM-C/CM group, -2.73 mm for the DBBM-C group, and -1.48 mm for the SH group. The median contour changes between crown insertion and 1 year were -0.19 mm in the DBBM-C/CM group, -0.09 mm in the DBBM-C group, and -0.29 mm in the SH group. Conclusions: Major vertical and horizontal ridge contour changes occurred, irrespective of the treatment modality, up to 8 weeks following tooth extraction. The DBBM-C/CM preserved more mineralized tissue throughout this period, despite a substantial reduction in the overall contour. All 3 protocols led to stable tissues for up to 1 year.

• The Journal of Advanced Prosthodontics
• /
• 제8권6호
• /
• pp.472-478
• /
• 2016

PURPOSE. The aim of this study was to analyze the shapes of lingual polished surfaces in lower complete dentures formed by polished surface impressions and to provide reference data for use when manufacturing edentulous trays and lower complete dentures. MATERIALS AND METHODS. Twenty-six patients with mandibular edentulism were studied. After lower wax dentures were fabricated, wax was removed from the lingual side of the wax denture and a lingual polished surface impression was obtained with tissue conditioner. The definitive denture was scanned with a three-dimensional scanner, and scanned images were obtained. At the cross-sections of the lingual frenum, lateral incisors, first premolars, first molars, and anterior border of the retromolar pads, three points were marked and eight measurements were taken. The Kruskal-Wallis test and a post hoc analysis with the Mann-Whitney test were performed. RESULTS. Each patient showed similar values for the same areas on the left and right sides without a statistically significant difference. The height of the contour of the lingual polished surface at the lingual frenum was halfway between the occlusal plane and lingual border, it moved gradually in a downward direction. The angle from the occlusal plane to the height of the contour of the lingual polished surface was increased as it progressed from the lingual frenum towards the retromolar pads. CONCLUSION. The shape of the mandibular lingual polished surface was convex at the lingual frenum, lateral incisors and gradually flattened towards the first molars and retromolar pads.

• 대한치과교정학회지
• /
• 제41권3호
• /
• pp.184-190
• /
• 2011

하악 절치부에서 보이는 총생은 하악 절치의 큰 MD/FL (mesiodistal/faciolingual) 인덱스와 관련이 있음이 보고되었다. 큰 MD/FL 인덱스를 보이는 절치에서 치간 삭제를 통해 근원심폭경을 줄여 MD/FL 인덱스를 줄이고 공간을 확보하는 방법이 정당화되기 위해서는 MD/FL 인덱스가 클수록 인접면 법랑질 두께가 더 두꺼워야 할 것이다. 본 연구의 목적은 하악 절치의 MD/FL 인덱스, 근원심폭경, 최대풍융부/치경부폭경비와 같은 치아의 형태적 요인과 인접면 법랑질 두께 사이에 상관관계가 있는지를 조사하는 것이었다. 발거된 하악 절치 40개에서 MD/FL 인덱스, 근원심폭경, 최대풍융부/치경부폭경비를 구하였으며, 근원심폭경을 구한 선상까지 순면을 연마하여 그 단면에서 법랑질 두께를 측정하였다. 치경부근원심폭경은 순면을 연마한 단면에서의 좌우측 백악법랑경계 사이의 폭경을 측정하였다. 이후 법랑질 두께와 MD/FL 인덱스, 근원심폭경, 최대풍융부/치경부폭경비의 상관관계를 조사하였다. 연구결과 하악 절치의 법랑질 두께는 편측에서 $0.75{\pm}0.07mm$였고, 근원심폭경은 $5.56{\pm}0.40mm$였다. 법랑질 두께와 근원심폭경 간에는 유의한 상관관계가 있었지만(R = 0.68), 법랑질 두께와 MD/FL 인덱스, 법랑질 두께와 최대풍융부/치경부폭경비 간에는 상관관계가 없었다. 이는 근원심폭경이 큰 치아에서는 치간 삭제를 더 많이 할 수 있지만, 동일한 근원심폭경을 갖는 절치들의 경우 MD/FL 인덱스가 큰 하악 절치 또는 최대풍융부/치경부폭경비가 커서 삼각형의 형태를 갖는 하악절치에서 치간 삭제를 더 많이 할 수는 없다는 것을 나타낸다.

• Journal of information and communication convergence engineering
• /
• 제6권1호
• /
• pp.100-104
• /
• 2008

Generally, it is difficult to find constant patterns on identifiers in a container image, since the identifiers are not normalized in color, size, and position, etc. and their shapes are damaged by external environmental factors. This paper distinguishes identifier areas from background noises and removes noises by using an ART2-based quantization method and general morphological information on the identifiers such as color, size, ratio of height to width, and a distance from other identifiers. Individual identifier is extracted by applying the 8-directional contour tracking method to each identifier area. This paper proposes a refined ART2-based RBF network and applies it to the recognition of identifiers. Through experiments with 300 container images, the proposed algorithm showed more improved accuracy of recognizing container identifiers than the others proposed previously, in spite of using shorter training time.