• 한국정밀공학회지
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• 제4권4호
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• pp.36-42
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• 1987

Very accurate calibration is needed to index tables which are necessary for precision angle measurement. The repeatability of index table is less than 0.2 second, so that attentions should be paid to choosing devices to be used in the calibration of index tables. The auto- collimators have been used in the calibration of index tables, but the repeatability of auto- collimators is bad compared with that of index table. In place of autocollimators, we described a method which uses electric comparators which are possessed by most precision measurement laboratories. Electric comparators are set to measure small angle displacement without interrupting the rotation of index tables and the signals of two electric comparators are added to remove the run-out errors of the shafts of index tables. Two index tables have been calibrated simulataneously by this method and the measurement data have been analyzed by the least squares method. We compare the calibration results with those of methods using autocollimator and auto- matic autocollimator and are able to know that the data of electric comparator method lie between the data of autocollimator methods. The repeatability of measurement is less than 0.02 second. The electric comparator method is economical and capable of reducing the uncertainty of the measurement.

• Industrial Engineering and Management Systems
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• 제13권4호
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• pp.454-462
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• 2014

Retention of possible churning customer is one of the most important issues in customer relationship management, so companies try to predict churn customers using their large-scale high-dimensional data. This study focuses on dealing with large data sets by reducing the dimensionality. By using six different dimension reduction methods-Principal Component Analysis (PCA), factor analysis (FA), locally linear embedding (LLE), local tangent space alignment (LTSA), locally preserving projections (LPP), and deep auto-encoder-our experiments apply each dimension reduction method to the training data, build a classification model using the mapped data and then measure the performance using hit rate to compare the dimension reduction methods. In the result, PCA shows good performance despite its simplicity, and the deep auto-encoder gives the best overall performance. These results can be explained by the characteristics of the churn prediction data that is highly correlated and overlapped over the classes. We also proposed a simple out-of-sample extension method for the nonlinear dimension reduction methods, LLE and LTSA, utilizing the characteristic of the data.

• Journal of Biosystems Engineering
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• 제33권1호
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• pp.58-62
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• 2008

The need for position information in agriculture is gradually increasing for precise control farm vehicle and effective manage farm land. Though geomagnetic sensor has a lot of merits in estimating heading angle of vehicle because of low costs and sensing ability of magnetic north, it is easy that sensor outputs are distorted in electro magnetic field environment. This study was conducted to develop geomagnetic compass which could be available in measuring relative position from reference point correcting output distorted by external electro magnetic field in a small scale field. Magnetic inducing sensor (PNI's Vector2X) which wound enamel coated copper coil on ferrite core in order to measure and correct earth magnetic field. Magnetic azimuth was corrected using the algorithm which estimated amount of magnetic distortion from the difference between each outputs of magnetic sensors that located on the cross shaped base. Developed auto-tuning magnetic sensor was showed less then 5% as bearing accuracy in the strong magnetic field.

• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.393-398
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• 2007

In this paper, we propose the development of Artificial Hippocampus Algorithm(AHA) which remodels a principle of brain of hippocampus. Hippocampus takes charge auto-associative memory and controlling functions of long-term or short-term memory strengthening. We organize auto-associative memory based 4 steps system (EC, DG CA3, and CA1) and improve speed of teaming by addition of modulator to long-term memory teaming. In hippocampus system, according to the 3 steps order, information applies statistical deviation on Dentate Gyrus region and is labeled to responsive pattern by adjustment of a good impression. In CA3 region, pattern is reorganized by auto-associative memory. In CA1 region, convergence of connection weight which is used long-term memory is learned fast a by neural network which is applied modulator. To measure performance of Artificial Hippocampus Algorithm, PCA(Principal Component Analysis) and LDA(Linear Discriminants Analysis) are applied to face images which are classified by pose, expression and picture quality. Next, we calculate feature vectors and learn by AHA. Finally, we confirm cognitive rate. The results of experiments, we can compare a proposed method of other methods, and we can confirm that the proposed method is superior to the existing method.

• 대한전자공학회논문지SD
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• 제44권3호
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• pp.12-19
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• 2007

본 논문에서는 피사체 인식 및 자동 선택이 가능한 모바일 폰 용 자동초점 알고리즘을 제안하였다. 제안된 알고리즘은 피사체 인식 단계와 목적물 자동 선택 단계로 구성된다. 피사체 인식 단계에서는 화면 전체에 배치된 다중 소형 측거점과 초점값 연산자를 사용하여 복수개의 피사체를 모바일 폰에 내장된 이미지 센서만을 사용하여 인식함으로써 기존의 적외선이나 초음파와 같은 외부 장치를 사용하는 방식과 달리 모바일 폰에서의 피사체 인식을 가능케 하고자 하였다 목적물 자동 선택 단계에서는 퍼지 멤버십 변수와 퍼지 추론을 통해 사용자가 촬영하고자 하는 목적물을 자동 선택하는데 이는 사진 기술이 없는 사용자라도 선명한 화질의 디지털 이미지를 획득할 수 있도록 하기 위함이다. 제안된 알고리즘은 프로그램 언어로 구현되었으며, 초점 거리 제어가 가능한 CCD 카메라와 PC를 사용하여 실시간으로 이미지를 분석, 검증하였다.

• 대한물리의학회지
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• 제11권4호
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• pp.27-32
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• 2016

PURPOSE: This study compared the immediate effect of a passive mobilization of upper cervical spine (Kaltenborn's joint mobilization) and an active upper cervical stretching (Olaf's Auto-stretching) on patients with neck pain and ROM. METHODS: Twenty-three subjects were randomized selected in the passive group (Kaltenborn's joint mobilization) included twelve subjects and the active group (Olaf's Auto-stretching) included eleven subjects. VAS (Visual Analogue Scale) was measured before and after neck rotation performance. DUALER IQ PRO (JTECH Medical, U.S.A.) was used to measure the neck ROM. Mean value of double measurement was used before performance and after performance. SPSS version 18 was used to compare values independent t-test and paired t-test were used to compare pain and ROM. RESULTS: There are significant difference in the pain and the ROM in both of two group (p<.05). But there are no significant difference pain and ROM between two groups. CONCLUSION: Both of the passive mobilization of upper cervical spine and the active upper cervical stretching are effected on symptom improvement of patients with neck pain reduction and ROM increasing. Especially active upper cervical stretching is more economical, because it has similar effects with the passive mobilization, help to maintain the treatment effect of therapist by themselves and can help to save medical expenses of patients.

• 한국정밀공학회지
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• 제13권3호
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• pp.42-48
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• 1996

In this paper, a position correction system of industrial robot for door-chassis assembly tast is developed in connection with the position correction algorithm shown in Part I. Tow notches and a hole of auto chassis are selected as the reference measure points and a vision based error detection algorithm is devised to measure in accuracy of less than 0.07mm. And also, the transformation between base and tool coordinates of the robot is shown to send the suitable correction quantities caaording to robot's option. The obtained algorithms were satisfactorily implemented for a real door-chassis model such that the system could accomplish visually acceptable door-chassis assembly task.

• 대한디지털의료영상학회논문지
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• 제3권1호
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• pp.126-132
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• 1997

Purpose : To apply to Program of Auto processor quality control after comparison of Film density variations with amendments to Auto density by using Check density program and Adjust density program of calibration mode into the Laser imager. Methods : Observe Check and Adjust density variations on the Control chart with standard step and value during seven months from December, 1995 to June, 1956 extending twice a week. (1) Measure density value on the steps after printing out 17-step sensitometric pattern of the Check density program. (2) In the same way, measure density values after amending density by using Adjust density program If they are exceeding allowable error limit. Results : In case of Check density program, the exceeding limit rates of Density difference(DD) and Middle density(MD) are: FL-IM3543 DD=75%. MD=72.5%, FL-IMD DD=0%. MD=30.8%(14.5%) After amending density by using Adjust density program, the exceeding limit rates of all both Laser imager were zero percent. The standard deviations are show lower FL-IM D than FL-IM3543 on the Check density control chart, but higher on the Adjust density control chart. Conclusion : (1) Check density variations by printingout sensitometric pattern extending once a week at least for quality control of the Laser imager. (2) In case of a dusty place, check the Laser beam transmission after cleaning Laser optical unit extending once a month. (3) Be sure to measure and check density values by using adjust density program if they are exceeding allowable error limit. (4) Maintain much better film density by performing the adjust density program even if check density values are existed within normal limit.

• 대한전자공학회논문지SP
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• 제48권2호
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• pp.80-87
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• 2011

본 논문은 잡음에 강인한 초점 값을 이용한 피사체 중심의 자동초점 알고리듬을 제안한다. 제안된 방법은 영상의 엔트로피를 이용하여 피사체가 존재하는 영역을 자동으로 추정함으로써, 배경에 의해 잘못된 자동초점 결과를 얻는 문제점을 개선하였다. 또한 이산 코사인 변환 계수를 분석하여 새로운 초점 값 계산 방법을 제안하였고, 실험결과를 통해 기존의 알고리듬에 비해 제안된 방법이 가우시안 잡음과 임펄스 잡음이 있는 경우에도 초점 값 특성이 강인함을 검증하였다. 제안하는 자동초점 알고리듬은 지능형 감시 시스템의 팬-틸트-줌 카메라 등에 적용 가능하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.286-288
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• 2003

Accidents at level crossing where railways and roads cross cause many casualties because of collision of cars etc and it also has a risk of the 2nd accident of trains. it is the most vulnerable point in the railway safety. Fundamental solution for accidents at level crossing is making the crossings cubic. but it can't be easily progressed because of environmental and financial difficulties. every kind of anti-accident measures are being strived for. one of the strived results is level crossing obstacle detector which automatically detects obstacles like defected cars etc in the middle of level crossing and transmits the information of obstacles to the approaching train. However present level crossing obstacle auto detector needs high expenses to be installed and has difficulties that lenses of beam transmitter, beam receiver should be cleaned in snowing winter. this document reviews level crossing obstacle auto detector using ultrasonic sensor to measure these difficulties.