• 제어로봇시스템학회논문지
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• 제19권11호
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• pp.984-990
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• 2013

Pick and placement systems need high speeds and reliability for the position alignment process of semiconductor packages in picking up and placing them on placement trays. Image processing is usually adopted for position aligning where finding out the most suitable method is considered most important aspect of the process. This paper proposes a method for judging the performance of different image processing algorithms based on the PCI (Process Capability Index). The PCI is an index which represents the error distribution acquired from many experimental data. The bigger the index, the more reliable the results or the lower the deviation. Two compared and candidate methods are Hough Transform and PCA (Principal Component Analysis), both of which are very suitable for oblong or rectangular type packages such as BGA's. Comparing the two approaches through a CPI with enough experimental results leads to the conclusion that the PCA is much better than the Hough Transform in not only reliability, but also processing speed.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.18-21
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• 2020

Undetected wafer slip during the lift pin-down motion in semiconductor equipment may affect the center to edge variation, wafer warpage, and pattern misalignment in plasma equipment. Direct measuring of the amount of wafer slip inside the plasma process chamber is not feasible because of the hardware space limitation inside the plasma chamber. In this paper, we demonstrated a practice for the wafer lift pin-up and down motions with respect to the gear ratio, operating voltage, and pulse width modulation to maintain accurate wafer position using remote control linear servo motor with an experimentally designed chamber mockup. We noticed that the pin moving velocity and gear ratio are the most influencing parameters to be control, and the step-wised position control algorithm showed the most suitable for the reduction of wafer slip.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.865-868
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• 2005

This paper presents analysis of dynamic characteristics of a high-speed milling spindle with a built-in motor. The spindle system with a built-in motor can be used to simplify the structure of machine tools. to improve tire machining flexibility of machine. tools, and to perform the high speed machining. In this system the shaft is usually assumed as a rigid rotor. In the spindle system design, it is very important to improve modal characteristics, and modal analysis is performed in the first place. Therefore in this paper, on the assumption that supporting bearings of spindle was selected most suitable condition, analyzed dynamic characteristics of a high-speed spindle according to its position. Optimal design was applicated to select most suitable position of bearings. Considered tile mass and stiffness effects of the built-in motor's rotor are analyzed by numerical method. The result shows the natural frequency of 1st bending mode of spindle.

• International Journal of Precision Engineering and Manufacturing
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• 제4권1호
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• pp.43-48
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• 2003

A linear laser-vision sensor called ‘Perception TriCam Contour' is mounted on an industrial robot and often used for various application of the robot such as the position correction and the inspection of a part. In this paper, a sensor center position calibration is presented for the most accurate use of the robot-Perceptron system. The obtained algorithm is suitable for on-site calibration in an industrial application environment. The calibration algorithm requires the joint sensor readings, and the Perceptron sensor measurements on a specially devised jig which is essential for this calibration process. The algorithm is implemented on the Hyundai 7602 AP robot, and Perceptron's measurement accuracy is increased up to less than 1.4mm.

• 한국도로학회논문집
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• 제19권6호
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• pp.31-36
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• 2017

PURPOSES : The computational fluid dynamics of flow and fine particles in a road were set to determine the insert flow and occurrence characteristics. METHODS : The road extension was 100 m with two lanes. A one-ton truck traveled a 50-m distance. After a noise barrier was installed on one side of the road, the flow and a collision analysis were tested. RESULTS : The flow that occurred was 5 m/s beside the vehicle, and fine particulate was $5.0{\times}10^2{\mu}g/m^3$ after 20 m from the exhaust vent. CONCLUSIONS : After a collision analysis of the fine particulate on the noise barrier to find the most suitable position of the filter panel in height, the bottom 1 m was the most optimum position because 88.1% of the distribution was concentrated there.

• 한국항해항만학회지
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• 제37권4호
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• pp.351-357
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• 2013

우리나라는 전 세계적으로 많은 원유를 수입하는 국가 중 하나이다. 그리고 국내 몇몇 항들은 수입한 원유를 육상시설로 이송하기 위한 원유브이를 운영하고 있다. 이러한 상황에서 최근 울산항은 울산 신항의 개발에 따른 방파제 신설로 기존에 설치되어 있는 원유브이를 이설하고, 추가적으로 1기의 원유브이를 신설할 예정이다. 이에 따라 이설 및 신설하고자 하는 원유브이의 최적 위치 설정이 필요하게 되었는데 현재 국내외적으로 원유브이 위치 설정에 대하여 체계적이고 일관된 기준이 수립되어 있지 않은 실정이다. 이에 본 연구에서는 국내외 원유브이 설치 운영 사례에 관한 선행 연구 자료를 분석 검토하고, 관련 기관 및 전문가 의견 수렴 결과를 바탕으로 한 분배율을 제시하고, 단순가중치 첨가법(SAW)을 이용하여 원유브이 설치 기준을 제시하고자 한다.

• 한국기계가공학회지
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• 제1권1호
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• pp.5-14
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• 2002

Hemisphere shapes were machined for different tool paths and machining conditions with ball endmill cutters. It was also found out how feedrate affect the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Tool deflection, cutting forces and shape accuracy were measured according to the inclination position of the sculptured surface. As the decreasing of inclination position angle, the tool deflection was increased due to the decreased cutting speed when the cutting edge is approaching toward the center. Tool deflection when upward cutting IS obtained less than that of downward cutting and down-milling in upward cutting showed the least tool deflection for the sculptured surface. For down-milling, the cutting resistance of the side wall direction is larger than that of feed direction. It was found that the tool deflection is getting better as tool path is going to far from the center for convex surface.

• Journal of Chest Surgery
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• 제15권2호
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• pp.188-193
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• 1982

Between 1967 and 1980, a total of 99 patients with a benign stricture of esophagus, resulting from a chemical burn, underwent a reconstructive procedure in which various segments of colon were used to bridge the gap between the cervical esophagus and the stomach. There were 42 males and 57 females and most were in their twenties and thirties. The most frequent site of the stricture was upper 1/3 of the thoracic esophagus [48.5%] and the next most common site was the low cervical esophagus [23.2%]. In 89 cases, the right colon with or without the terminal ileum was used as the conduit in an isoperistaltic manner and in 10, the left colon was used in an antiperistaltic position, because the right colon was not suitable as the conduit. There was a higher incidence of regurgitation [90% vs 0%], leakage at cervical anastomosis [80% vs 27%] and stenosis at anastomotic site [70% vs 15%] in an antiperistaltic left colon anastomosis, as compared to isoperistaltic right colon anastomosis. This was felt to be due to the orad peristaltic motion of the transplanted colon which acted as a functional obstruction distal to the esophagocolic suture line, resulting in breakdown of the anastomosis, leakage and eventual stenosis at the site of anastomosis. In conclusion, colon is useful and effective conduit as an esophageal substitute. Either the right or the left colon can be used for this purpose, provided that it is placed in an isoperistaltic position to minimize some of the complications listed above.

• 약학회지
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• 제6권2호
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• pp.23-28
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• 1962

To reduce the errors, in the microdetermination of carbon and hydrogen, by the electrical automatic combustion apparatus, measured the errors due to the positions of sample in the carbon and hydrogen combustion tube. The samples used are glucose, acetanilide, phenacetin and diazoaminobenzene. Experimented positions of samples were 3cm, 5cm, 7cm, and 9cm from the front edge of the long stationary burner. In this experiment, it was found that the most suitable position of sample in the carbon and hydrogen combustion tube is 8cm from the long stationary burner.

• 구강회복응용과학지
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• 제17권4호
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• pp.275-282
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• 2001

Centric relation is defined the horizontal position between maxilla and mandible when condylar head of mandible is positioned adequately in mandibular fossa. The most recent concept of centric relation position is defined as the mandibular position in which the condyles are in their most superoanterior position in the articular fossa, resting against the posterior slope of the articular eminences, with the articular disk properly interposed. To be suitable as a reference point during occlusal management, a mandibular position of centric relation has to be functionally acceptable to the patient and clinically reproducible and achievable during everyday practice. There are numerous methods for determination of centric relation, and in this study we used three of them, Gothic arch tracing(Group I), leaf gauge(Group II), and anterior jig(Group III). The subjects were 10, 8 men and 2 women, age-ranged from 23 to 26 years old, had no prosthetics in thier mouth, and had no sign and symptom of temporomandibular disorders. We gained three occlusal records using each method, and then the degree of the reproducibility was examined with split cast technique. In this study the reproducibility of centric relation using split cast technique was greater in the order of Group I(mean 1.6), Group II(mean 1.4), and Group III(mean 1.3), but there was no significant differences among them statistically(p>0.05).