• Journal of the Korea Convergence Society
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• v.8 no.5
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• pp.19-28
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• 2017

In this paper, we propose a method to reduce the difference in image characteristics when multiple camera images are captured for virtual space production. Sixty-four images were used by cross-mounting eight bodies and lenses, respectively. Image analysis compares and analyzes the standard deviation of the histogram and pixel distribution values. As a result of the analysis, it shows different image characteristics depending on the lens or image sensor, though it is a camera of the same model. In this paper, we have adjusted the distribution of the overall brightness value of the image to compensate for this difference. As a result, the average deviation was the maximum of (Indoor: 6.89, outdoor: 24.23), we obtained images with almost no deviation (Indoor: maximum 0.42, outdoor: maximum: 2.73). In the future, we will study and apply more accurate image analysis methods than image brightness distribution.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.147-153
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• 2014

In this paper, we present a non-dyadic lens distortion correction model and image restoration method based on local self-similarity to remove jagging and blurring artifacts in the peripheral region of the geometrically corrected image. The proposed method can be applied in various application areas including vehicle real-view cameras, visual surveillance systems, and medical imaging systems.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1341-1348
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• 2013

To solve the classification problems, various data mining techniques have been applied to database marketing, credit scoring and market forecasting. In this paper, we compare various techniques such as bagging, boosting, LASSO, random forest and support vector machine with the daily lens transaction data. The classical techniques-decision tree, logistic regression-are used too. The experiment shows that the random forest has a little smaller misclassification rate and standard error than those of other methods. The performance of the SVM is good in the sense of misclassfication rate and bad in the sense of standard error. Taking the model interpretation and computing time into consideration, we conclude that the LASSO gives the best result.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.1
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• pp.73-82
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• 1997

This paper discusses the design and implementation of parabola, lens, and $32{\times}8$ rectangular microstrip patch array antennas at 77GHz for vehicular radar applications. The parabola size was $7{\times}10$ cm and the f/D was 0.263. Open waveguide(WR-12) was utilized as the feed antenna. Two types of lens antennas with f/D=0.5 were investigated ; one was a plano-convex and the other was a double-convex. A patch array antenna was designed using a transmission line model and experimented. Comparing the theoretical values with the measured ones for four antennas, the results were agreed well in 3 dB BW and radiation patterns, while the gain of the patch array antenna was degraded as much as -25 dB due to the feed network and microstrip-to-coax-to-waveguide transition losses.

• Korean Journal of Optics and Photonics
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• v.17 no.2
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• pp.113-119
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• 2006

We need a good image of the retina of the human eye in order to inspect or cure it. In this work, an optical system design for a retinal camera is studied and the finite schematic eye model made by Sang Gee Kim and Sung Chan Park is used. The optical system is composed of four lens groups. The rays of the entire object field are collected on the center by the 1st group and the objective is imaged by all the other groups. The image is detected by the CCD array and displayed by a monitor The 1st lens group is employed singlet and other groups are employed triplets. Ray aberrations, spot diagrams, diffraction line spread functions and MTFs are calculated for optical performance assessment. This design may be very useful for the development of a retinal camera with high performance.

• Journal of Intelligence and Information Systems
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• v.9 no.3
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• pp.117-135
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• 2003

This study is to propose a procedure solving scale problem of traditional collaborative filtering (CF) approach. The CF approach generally uses some similarity measures like correlation coefficient. So, as the user of the Website increases, the complexity of computation increases exponentially. To solve the scale problem, this study suggests a clustering model-based approach using Self-Organizing Map (SOM) and RFM (Recency, Frequency, Momentary) method. SOM clusters users into some user groups. The preference score of each item in a group is computed using RFM method. The items are sorted and stored in their preference score order. If an active user logins in the system, SOM determines a user group according to the user's characteristics. And the system recommends items to the user using the stored information for the group. If the user evaluates the recommended items, the system determines whether it will be updated or not. Experimental results applied to MovieLens dataset show that the proposed method outperforms than the traditional CF method comparatively in the recommendation performance and the computation complexity.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.13-29
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• 2001

A mathematical model was proposed to analyze the vibration of diaphragm, such as the contact lenses fitted on the eyes, being subjected to the external sinusoidal pressure. The model incorporates the differential equations and their numerical solution program, based on the wave equations. Turbo-C and graphic software, formulated to describe the dependence of the various parameters involved in the vibration. The model predicts the radial distribution of amplitude, frequency dependence of both average displacement amplitude and the power of diaphragm whose edge is being either simply supported or rigidly clamped in vibration. The effect of variables such as thickness, radius, damping coefficients on the vibration characteristics was illustrated by the computer simulation of the derived program. As the frequency of driving pressure increases above the certain value determined by the boundary conditions and parameters the wave shape or pattern changes from simple arc to belly or loops having double antinode. It seems that the effect of outer antinode progressively increases as the frequency increases. If this kind of phenomena occurs to the contact lens on the cornea in vivo, it may cause an abnormal correction power in the lenses or pull off the eye due the increased rise of outer part of the lens.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.3
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• pp.547-561
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• 1999

The purpose of this study was to determine which nursing activities are performed for patients in each of the nine KDRGs and to examine common nursing activities between patients with the nine KDRGs and special nursing activities which were not common to patients with the nine KDRGs. The study will provide basic data for estimation of nursing fees. The nine KDRGs in model project are Lens procedures, tonsillectomy, &/or adenoidectomy, appendectomy &/or not complicate principal diagnosis, vaginal delivery, cesarean section, anal & stomal procedures, inguinal & femoral hernia, uterine & adneza procedure for nonmalignancy, and simple pneumonia & pleurisy. To determine the nursing activities for each of the nine KDRG, checklists of nursing activities in each nine KDRG were developed from the literature and a total of 115 records of patients 'who were diagnosed and discharged between January and April, 1999 from a tertiary medical center. Nursing activities for each of the nine KDRG were verified through two consecutive content analyses. The results of study are followed as: 1. The checklists of nursing activities developed included direct and indirect nursing activities, for a total of 241 nursing activities. Direct nursing consisted of physical, educational, emotional-socioecomomic-spiritual nursing in 17 areas. Indirect nursing had four areas. 2. Through the two consecutive content analyses, 197 nursing activities were selected, having item CVIs of .83 or more. Those included 81 nursing activities for Lens procedures, 95 for Tonsillectomy &/or Adenoidectomy. 93 in Appendectomy &/or not complicated principal diagnosis, 155 for vaginal delivery, 172 for cesarean section, 89 for anal & stomal procedures, 93 for inguinal & femoral hernia, 108 for uterine & adneza procedures for non-malignancy, and 68 for simple pneumonia & pleurisy. 3. Nursing activities for each of the nine KDRG were compared. Activities with 80% or higher commonality within the nine KDRGs consisted of 86 of 197 nursing activities for the total designated common nursing activities, 30 common nursing activities for patients in the operation group, 45 common activities for patients in the delivery Group. Special nursing activities not common within the nine KDRGs were : 3 for Lens procedures, 1 for Tonsillectomy &/or Adenoidectomy. 2 for Appendectomy &/or not complicated principal diagnosis, 27 for vaginal delivery, 21 for Cesarean section, 6 for anal & stomal procedures, 3 for inguinal & femoral hernia, 16 for uterine & adneza procedure for non-malignancy, 8 for simple pneumonia & pleurisy. In this study, nursing activities for each of the nine KDRGs verified through two consecutive content analyses are those that are performed in the hospital. And, nursing activities for each of the nine KDRGs included all nursing activities from hospital admission to discharge. So. the checklists consisted of nursing activities that allow for an estimation of nursing fees under PPS. The classification of nursing activities in the study will provide a reference for the development of a nursing activity classification.

• Journal of The Korean Association For Science Education
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• v.41 no.2
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• pp.155-169
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• 2021

This study aims at exploring the features of science teaching orientation (STO) and its relationships with other PCK (pedagogical content knowledge) components. To do this, based on the definition of STO by Friedrichsen, Driel, & Abell(2011) and PCK model by Magnusson, Krajcik, & Borko(1999), we observed one experienced elementary teacher's science lessons for 21 lesson hours (10 hours of 'Motion of Objects' and 11 hours of 'Light and Lens') and carried out qualitative analyses of the data obtained from lessons observation, teacher interviews, and CoRe (content representation) responses. We analyzed the teacher's three aspects of STO (i.e. beliefs about the goals and purpose of science teaching, beliefs about the nature of science, and beliefs about science teaching and learning) which can converge into an overall STO of 'inquiry'. And these aspects of STO appear to interact differently with four PCK components (i.e. curriculum knowledge, learner knowledge, instructional knowledge, and assessment knowledge) depending on the topic of the lesson. It is hoped that this in-depth understanding of the features of STO and its relationship with other PCK components would provide useful information on how to monitor and improve STO and PCK of elementary teachers.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.9-14
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• 2009

In this work applicability of a sharp-interface model to well-scale problems is examined. In coastal areas one of the main concerns in groundwater development is saltwater intrusion. To determine the saltwater intrusion at a well one needs to evaluate the saltwater content from a pumping well. We conducted laboratory sand-tank experiments to determine if a sharp-interface model can simulate the saltwater content of a pumping well. Lateral saltwater intrusion experiments and freshwater lens experiments are conducted. A partially penetrating well and a fully penetrating well are used. Comparison between numerical results and observation results indicates that the sharp-interface model can determine saltwater contents reasonably well. We conclude that a sharp-interface model can be applied to well-scale groundwater flow problems in coastal areas.