• 한국방사선학회논문지
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• 제5권6호
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• pp.309-313
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• 2011

과산화테크네슘($^{99m}Tc$-pertechnetate)을 이용한 갑상선 검사에서 갑상선 섭취율 측정과 갑상선 스캔을 위해 두 번의 정맥주사와 두 번의 대기시간이 필요하다. 이를 해결하기 위해 감쇄필터(Attenuation Filter)를 이용하여 과산화테그네슘($^{99m}Tc$-pertechnetate)의 1회 정맥주사로 갑상선 섭취율과 스캔을 동시검사 할 수 있는 방법을 연구하고자 하였다. 그에 따른 결과로는 감쇄필터를 사용하지 않은 그룹과 사용한 그룹간의 유의한 상관관계로 나타났다. 따라서 1회 주사를 통한 갑상선 섭취율 측정과 스캔을 동시에 할 수 있게 되어 임상에서 많이 활용될 것으로 사료된다.

• 대한핵의학회지
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• 제17권2호
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• pp.57-62
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• 1983

Diuretic renal scan, a modified method of conventional radionuclide renography by administration of intravenous furosemide was performed in 54 patients with suspected urinary tract obstruction. Two showed normal responses, 41 showed increased washout patterns, and the remainder 15 revealed no changes in response to the furosemide administration. IVP was done in 34 patients. In comparision to the diuretic renal scan, the following results were obtained. 1) Patients with normal results by the scan, showed normal IVP findings also. 2) 10 patients who showed delayed excretory patterns not influenced by the diuretics administration. 9 patients revealed obstructive lesions and hydronephrotic changes, and CPN was diagnosed for the remainder one and the one patient without obstruction was diagnosed as chronic pyelonephritis. 3) 22 patients showed positive results to the diuretics. Among them 10 patients had positive results in IVP. but, were not related to the speed of decrement of the renal activity after the furosemide administration.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1255-1258
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• 2008

Roll to roll (R2R) system, known as 'web processing', is the process of producing these electronic devices on a roll of flexible plastic. With the need of improved performance and productivity in R2R industry, effective control and on-line supervision for web quality is essential. In this report, we present a system for on-line measurement of wrinkles, one of defects incurring due to compressive stresses developed in the web. This system is able to capture an image generated when a well defined line shape laser beam passes through a transparent web. The system calculates 3D shape information, including the height of the wrinkle on the web, and displays the images for the shape information of the web in real time. By using area scan camera and machine vision laser, this system takes more advantages of setting up as a simple and low cost system compared to the line scan camera systems that widely used in web manufacturing. Specific calibration method and analysis on the achievable accuracy will be discussed.

• 대한의용생체공학회:의공학회지
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• 제3권1호
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• pp.35-42
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• 1982

The objective of this phantom study is to develop a digital method for improving the lateral resolution of B-scan ultrasonographic images irs medical application of ultrasound. By utilizing a discrete state-space modeling approach and Kalman-Buch method for analysis of the transducer's beam profile and the measurement and sampling noise, a stable recursive restoration of the object image was obtained for improved lateral resolution. The point spread function (PSF) was measured for the reflective signals after scanning the small pins located along the depth of interest. One major advantage of the present recursive scheme over the transform method is in its applicability for the space-variant imaging, such as in the case of the rotational movement of transducer.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.151-159
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• 2014

Computed tomography (CT) is one of the most widely used medical imaging modality. However, substantial x-ray dose exposed to the human subject during the CT scan is a great concern. Region-of-interest (ROI) CT is considered to be a possible solution for its potential to reduce the x-ray dose to the human subject. In most of ROI-CT scans, the ROI is set to a circular shape whose diameter is often considerably smaller than the full field-of-view (FOV). However, an arbitrarily shaped ROI is very desirable to reduce the x-ray dose more than the circularly shaped ROI can do. We propose a new method to make a non-circular convex-shaped ROI along with the image reconstruction method. To make a ROI with an arbitrary convex shape, dynamic collimations are necessary to minimize the x-ray dose at each angle of view. In addition to the dynamic collimation, we get the ROI projection data with slightly lower sampling rate in the view direction to further reduce the x-ray dose. We reconstruct images from the ROI projection data in the compressed sensing (CS) framework assisted by the exterior projection data acquired from the pilot scan to set the ROI. To validate the proposed method, we used the experimental micro-CT projection data after truncating them to simulate the dynamic collimation. The reconstructed ROI images showed little errors as compared to the images reconstructed from the full-FOV scan data as well as little artifacts inside the ROI. We expect the proposed method can significantly reduce the x-ray dose in CT scans if the dynamic collimation is realized in real CT machines.

• Journal of Welding and Joining
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• 제21권2호
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• pp.102-110
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• 2003

A visual sensor consisted of polygonal mirror, laser, and CCD camera was proposed to measure the distance to the weld joint for recognizing the joint shape. To scan the laser beam of the sensor onto an object, 8-facet polygonal mirror was used as the rotating mirror. By locating the laser and the camera at axi-symmetrical positions around the mirror, the synchronized-scan condition could be satisfied even when the mirror was set to rotate through one direction continuously, which could remove the inertia effect of the conventional oscillating-mirror methods. The mathematical modelling of the proposed sensor with the optical triangulation method made it possible to derive the relation between the position of an image on the camera and the one of a laser light on the object. Through the geometrical simulation of the proposed sensor with the principal of reflection and virtual image, the optical path of a laser light could be predicted. The position and direction of the CCD camera were determined based on the Scheimpflug's condition to fit the focus of any image reflected from an object within the field of view. The results of modelling and simulation revealed that the proposed visual sensor could be used to recognize the weld joint and its vicinity located within the range of the field of view and the resolution. (Received February 19, 2003)

• Advances in biomechanics and applications
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• 제1권1호
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• pp.67-76
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• 2014

Bone properties are one of the key components when constructing models that can simulate the mechanical behavior of a mandible. Due to the complexity of the structure, the tooth, ligaments, different bones etc., some simplifications are often considered and bone properties are one of them. The objective of this study is to understand if a simplification of the problem is possible and assess its influence on mandible behavior. A cadaveric toothless mandible was used to build three computational models from CT scan information: a full cortical bone model; a cortical and cancellous bone model, and a model where the Young's modulus was obtained as function of the pixel value in a CT scan. Twelve muscle forces were applied on the mandible. Results showed that although all the models presented the same type of global behavior and proximity in some locations, the influence of cancellous bone can be seen in strain distribution. The different Young's modulus defined by the CT scan gray scale influenced the maximum and minimum strains. For modeling general behavior, a full cortical bone model can be effective. However, when cancellous bone is included, maximum values in thin regions increase the strain distribution. Results revealed that when properties are assigned to the gray scale some peaks could occur which did not represent the real situation.

• 한국통신학회논문지
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• 제22권9호
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• pp.2080-2089
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• 1997

최근 급격히 발전된 컴퓨터 기술에 힘입어 다양한 분야에서의 멀티미디어 데이터 처리가 가능하게 되었다. 그러나, 기존의 디스크 저장 시스템으로 멀티미디어의 특징을 수용하기에는 무리가 있다. 현재, 몇몇의 연구에서 멀티미디어 저장에 관한 향상된 기술을 소개하였고, 그 중 Bocheck는 엑세스 주기와 단위가 동일한 다중스트림의 분할 저장 기법을 제안하였으나, 서로 상이한 주기를 갖는 연속 미디어의 스트림에 관해서는 고려되지 않았다. 이 논문에서는 조회 주기가 서로 상이한 스트림을 고정된 몇 개의 블록으로 할당하는 방안을 제안하고 주어진 다중스트림을 m개의 시퀀스로 스케줄링시 그 가능성을 분석하였으며, 기존의 Scan-EDF와 디스크 분할 저장 방식과 비교하기 위해서 시뮬레이션을 행하였다.

• 한국의상디자인학회지
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• 제22권1호
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• pp.1-13
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• 2020

The purpose of this study is to create a 3D avatar from 3D human body shape data using the CLO 3D virtual clothing program and to verify the feasibility of avatar production using the virtual clothing system for verifying size and shape. The research method was to select one virtual representative model that is the closest to the mean size of each body item for each age group. Using the 3D human body scan shape of a 40-69 years old male was applied to the CLO 3D virtual wearing system. Using the CLO 3D Avatar conversion menu, we verified the feasibility of creating a 3D avatar that reproduces the human body scan shape. In the dimension comparison between the 3D avatar and the fictitious representative model, the dimension difference was noticeable in height, circumference, and length. However, as a result, the converted 3D avatar showed less than a 5% difference in most human dimensions. In addition, since the body shape and posture were reproduced similarly, the utilization of the avatar was verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1623-1627
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• 2002

If the ambient temperature rises in AC PDP, some of the discharged cells arc turned off because of the addressing failure. Particularly, the addressing failure at the last scan line is more serious than at the first scan line. The failure is accompanied with delay of the address discharge and reduction of total charge involved. In order to compensate this kind of misfiling, the progressively increasing address voltage waveform is used instead of constant one. In this method, we found that the total charge and address time at the last scan line are similar to those of the first line. As a result, we can have stable discharge without misfiring even at the high ambient temperature.