• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.85-91
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• 2013

Purpose: The purpose of this study is to investigate difference between manifest refraction (MR) and cycloplegic refraction (CR) with age and myopic value. Methods: Manifest and cycloplegic refractions were carried out on the patients of 229 myopic patients ($25.3{\pm}11.9$ years old). Results: The average results from a pre- and a postcycloplegic refraction showed a reduction of 0.19 D in myopia, 0.02 D in astigmatism and $1.85^{\circ}$ in astigmatism direction. Change of myopic value was higher in 30~40 age. Total 73 eyes of 229 patients who showed 0.50 diopter (D) in spherical, and a high degree of myopia group showed a higher discrepancy rate. Conclusions: The results found in the comparison of the value of the manifest refraction and cycloplegic refractions showed changes of myopic value was not significant with age of patient, but the group of high degree of myopia showed higher discrepancy rate.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.481-483
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• 2001

최근 전자제품의 초소형화에 따라, PCB 기판위의 부품의 집적도를 높이기 위해, 기존의 리드대신 부품 밑면에 볼(ball)이 격자형태로 배열되어 있는 BGA(Ball Grid Array) 형태의 팩키지가 많이 사용되고 있다. 하지만, BGA의 구조상 한번 장착되면 외관검사가 불가능하므로, 장착전 BGA의 검사가 필수적이다. BGA의 검사항목중 가장 중요한 항목인 볼 높이검사를 실시간으로 하기 위해서는 고속 비접촉 3차원 측정기술이 요구된다. 본 논문에서는 일반카메라보다 100배이상 높이 프로파일 취득속도가 빠른 3D smart camera와 레이저 슬릿광(slit ray)을 이용하여 고속으로 BGA 볼의 3D 프로파일을 얻은 후, clipping과 morphological filter를 사용하여 인접한 볼표면에서의 난반사로 인한 에러 데이터를 보정하여 정확한 3D 영상을 취득할 수 있는 시스템을 소개한다.

• Journal of the Korean Society for Nondestructive Testing
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• v.3 no.2
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• pp.40-43
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• 1984

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.293-298
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• 2012

Purpose: We compared static retinoscopy in eyes opened with cycloplegic refraction depending on the hyperopia for school-aged children. Methods: There were 59 eyes (30 patients) who were divided into 3 groups - the mild hyperopia (+0.25 D ~ +1.00 D), moderate hyperopia (+1.25 D ~ +2.00 D) and high hyperopia (+2.25 D or more). They all had 0.8 visual acuity or more. Autorefraction and retinoscopy were performed prior to cycloplegic refraction, and then copmared with manifest refraction and cycloplegic refraction. Results: Hyperopia measured with static retinoscopy tends to be measured higher than manifest refraction for school-aged children. Changes of spherical power was statistically significant (p < 0.001). Changes of astigmatism was not statistically significant (p > 0.05). Conclusions: The difference between cycloplegic refraction and static retinoscopy was not significant for hyperopic school-aged children. The use of retinoscopy was limited for opticians because of legal constraints. The usage of static retinoscopy in eyes opened for optician should be generalized under the conditions not using the cycloplegic.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.331-337
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• 2014

Purpose: This is a comparative experimental study on the amount of phoria by the removal time of binocular fusion. In this study, three tests were used for phoria test like Howell test, Thorington test and developed 3D polarizing test. Methods: In this study, it was considered the removal time of binocular fusion for measuring phoria. The three methods were used for measuring quantity of phoria: Howell test, Thorington test and developed 3D Polarizing test. The measurements progressed quickly to avoid eye-strain. So we designed the test charts for marking 3D display modules and the apparatus inserted lenses, like Maddox lens and prism, which are compatible with three phoria tests. The phoria at the moment separation was measured when the binocular fusion was broken through the apparatus and the that at the stable separation was measured when activity of the separated two images like indicated box and figure on horizontal axis stopped. Results: There were statistically significant difference between quantity of phoria at moment separation and that at stable separation. Amount of phoria at moment separation was relatively larger than amount of that at stable separation. In result in exophoria, the quantity of phoria at moment separation was higher than that at stable separation, and in phoria measured by developed 3D polarizing test, it shows the similar results at two condition. Conclusions: For exophoria, the amount of phoria at moment separation of binocular fusion was relatively larger than that at stable separation. The amount of difference between phoria values at moment separation and that at stable separation was alike among three phoria tests. Usually in working, there is no distinction between moment separation and stable separation. But there were definitely the difference between two ways to separate binocular fusion. Therefore, it is need for writing on prescription test name for measuring phoria and condition of separation of binocular fusion.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.186-194
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• 2004

Purpose: Membranoproliferative glomeulonephritis(MPGN) has been diagnosed in an increasing number of asymptomatic cases. These cases have been detected by school urinary screening test even though the total cases of MPGN show a decreasing trend. We have analyzed the clinical and pathological characteristics of children with MPGN according to the clinical manifestations at the time of disease presentation. Methods: A total of 18 patients who had been diagnosed with idiopathic MPGN by percutaneous renal biopsy from January 1990 to February 2004 were involved in our study. The patients were divided into 2 groups as the school urinary screening(A) group and the symptomatic(S) group according to the clinical manifestations at the time of disease presentation. Results: Out of the total 18 patients, 8(44.4%) were in the S group and 10(55.6%) were in the A group. The mean serum total protein, albumin and $C_3$ levels in the S group were significantly lower than those levels of the A group, respectively($4.9{\pm}1.2\;g/dL,\;vs\;7.0{\pm}0.5\;g/dL\;P=0.002,\;2.8{\pm}0.9\;g/dL\;vs.\;4.1{\pm}0.3\;g/dL\;P=0.002,\;63.9{\pm}36.4\;mg/dL\;vs.\;100.8{\pm}39.5\;g/dL\;P=0.041$). The mean total protein amount of 24 hour collected urine in the S group were significantly higher than that of the A group($3684.0{\pm}2601.3\;mg/m^2\;vs.\;559.4{\pm}4.6.9\;mg/m^2$, respectively, P=0.001). Hypocomplementemia was observed in 11(61.1%) out of 18 patients at the time of disease onset, 7(87.5%) in the S group and 4(40%) in the A group. However the hypocomplementemia was decreased in 6(33.3%) out of 18 patients at the time of final follow-up, 3(37.5%) in the S group and 3(30%) in the A group. According to the pathologic type, hypocomplementemia was observed 8 patients(61.5%) with type I disease, 1 patients (100%) with type II disease, 2 patients(50%) in type III disease at the disease onset, but 4 patients(30.8%) in type I disease, 1 patient(100%) in type II disease, 1 patient(33.3%) with type III disease at the time of last follow-up. The incidence of cellular crescent formation and tubular atropy. as observed on light microscopy, were higher in the S group compared to the A group. Mean grade of capillary wall thickening and, mesangial proliferation were significantly higher in the S group. Conclusion: MPGN, as diagnosed in patients with only asymptomatic urinary abnormalities, has been increasing, it is more frequent in asymptomatic patients than in patients with presenting symptoms. Our result suggests that MPGN should be considered in the renal biopsy diagnosis regardless of serum $C_3$ level when urinary abnormalities are found by school urinary screening test.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.963-968
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• 2007

In this paper introduce Standard 3D object(Bounding-Volume). In 3D game very efficient control algorithm Using collision detection which controls the convenient of a game based on Standard 3D object specially collision-detection. This algorithm is designed LOD(Level-of-Detail) using Dynamic-Hierarchies of collision detection efficiency improvement in 3D object.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.6
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• pp.441-446
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• 2014

A 3D ultrasound image is desired in many medical examinations. However, the implementation of a 2D array, which is needed for a 3D image, is challenging with respect to fabrication, interconnection and cabling. A 2D sparse array, which needs fewer elements than a dense array, is a realistic way to achieve 3D images. Because the number of ways the elements can be placed in an array is extremely large, a method for optimizing the array configuration is needed. Previous research placed the target point far from the transducer array, making it impossible to optimize the array in the operating range. In our study, we focused on optimizing a 2D sparse array transducer for 3D imaging by using a simulated annealing method. We compared the far-field optimization method with the near-field optimization method by analyzing a point-spread function (PSF). The resolution of the optimized sparse array is comparable to that of the dense array.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.58-65
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• 2020

3D Models of offshore plant piping materials designed by 3D CAD systems are provided to the production processes in the form of 2D piping drawings and 2D piping installation drawings. In addition to the standard engineering information, the purchasing, procurement, manufacturing, installation, and inspection of raw materials are managed systematically in an integrated process control system. The existing integrated process management system can help reduce the processing time by managing the flow and progress of resources systematically, but it does not include 3D design model information. Hence, it is difficult to understand complicated pipe structures before installing the pipe. In addition, when design changes or immediate design modifications are required, it is difficult to find related data or exchange information quickly with each other. To solve this problem, an offshore plant-piping process-monitoring system was developed based on a 3D model. The 3D model-based piping monitoring system is based on Visual Studio 2017 C# and UNITY3D so that the piping-process work information can be linked to the 3D CAD model in real time. In addition, the 3D model could check the progress of the pipe installation process, such as block, size, and material, and the progress of functional inspection items, such as cleaning, hydraulic inspection, and pneumatic inspection.

• Journal of the Korean Society of Radiology
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• v.18 no.2
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• pp.127-133
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• 2024

The elbow joint is made up of three different bones. X-rays or other radiological exams are commonly used to diagnose elbow injuries or disorders caused by physical activity and external forces. Previous research on the elbow joint reported a new examination method that meets the imaging evaluation criteria in the tilt position by Z-axis elevation of the forearm. Therefore, this study aims to design an optimized instrument and develop an aid applicable to other upper extremity exams. After completing the 2D drawing and 3D modeling design, the final design divided into four parts was fabricated with a 3D printer using ABS plastic and assembled. The developed examination aid consists of a four-stage Z-axis elevation tilt angle function (0°, 5°, 10°, and 15°) and can rotate and fixate 360° in 1-degree increments. It was designed to withstand a maximum equivalent stress of 56.107 Pa and a displacement of 1.6548e-5 mm through structural analysis to address loading issues caused by cumulative frequency of use and physical utilization. In addition to X-ray exams of the elbow joint, the developed aid can be used for shoulder function tests by rotating the humerus and also be applied to MRI and CT exams as it is made of non-metallic materials. It will contribute to the accuracy and efficiency of medical imaging diagnosis through clinical applications of various devices and medical imaging exams in the future.