• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.1
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• pp.15-19
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• 2005

Conventional eddy current testing has been used for the detection of the defect-like fatigue crack in the conductive materials, such as aluminum, which uses a sinusoidal signal with very narrow frequency bandwidth, Whereas, the pulsed eddy current method uses a pulse signal with a broad bandwidth. This can allow multi-frequency eddy current testing, and the penetration depth is greater than that of the conventional eddy current testing. In this work, a pulsed eddy current instrument was developed for evaluating the metal loss. The developed instrument was composed of the pulse generator generating the maximum square pulse voltage of 40V, an amplifier controlled up to 52dB, an A/D converter of 16 bit and the sampling frequency of 20 MHz, and an industrial personal computer operated by the Windows program. A pulsed eddy current probe was designed as a pancake type in which the sensing roil was located inside the driving roil. The output signals of the sensing roil increased rapidly wich the step pulse driving voltage かn off, and the latter part of the sensing coil output voltage decreased exponentially with time. The decrement value of the output signals increased as the thickness of the aluminum test piece increased.

• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.343-350
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• 2003

This study was conducted to find out the coefficient relationships between intensity values of image processing and biological/physical parameters of soil in greenhouses. Soil images were obtained by an image processing system consisting of a personal computer and a CCD earners. A software written in Visual C$\^$++/ systematically integrated the functions of image capture, image processing, and image analysis. Image processing data of the soil samples were analyzed by the method of regression analysis. The results are as follows. For detecting soil density of unbroken soil samples, the highest correlation coefficients of 0.82 and 0.84, respectively were obtained fur R-value and S-value among image processing data while it was 0.97 for G-value. Considering the relationship between biological characteristics and image processing data of soil in greenhouse, the correlation was found generally low. For pH of unbroken soil sample, the correlation coefficients were found 0.87, 0.85, and 0.94, respectively with G, I, and H values of image processing data. In the case of bacteria, any correlation was not found with the image processing data For Actinomyctes, they were 0.86 and 0.85, respectively with G-value and B-value of image processing data showing high correlation coefficient compared to the other variables. The correlation coefficient between Fungi and H-value was shown 0.88, the highest among the variables higher than 0.8 while the other variables showed low correlation. For broken soil samples from greenhouse, the relation between biological parameter and image processing data were rarely shown in this study. The results of this study indicated that most of correlation coefficient between the variables were usually lower than 0.01. Accordingly, it was assumed that the soil should be used without broken to fairly estimate biological characteristics using CCD camera.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.172-180
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• 2001

A grape fruit is required for a lot of labor to harvest in time in Korea, since the fruit is cut and grabbed currently by hand. In foreign country, especially France, a grape harvester has been developed for processing to make wine out of a grape, not to eat a fresh grape fruit. However, a harvester which harvests to eat a fresh grape fruit has not been developed yet. Therefore, this study was designed and constructed to develope a image processing system for a fresh grape harvester. Its development involved the integration of a vision system along with an personal computer and two cameras. Grape recognition, which was able to found the accurate cutting position in three dimension by the end-effector, needed to find out the object from the background by using two different images from two cameras. Based on the results of this research the following conclusions were made: The model grape was located and measured within less than 1,100 mm from camera center, which means center between two cameras. The distance error of the calculated distance had the distance error within 5mm by using model image in the laboratory. The image processing system proved to be a reliable system for measuring the accurate distance between the camera center and the grape fruit. Also, difference between actual distance and calculated distance was found within 5 mm using stereo vision system in the field. Therefore, the image processing system would be mounted on a grape harvester to be founded to the position of the a grape fruit.

• Convergence Security Journal
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• v.5 no.2
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• pp.19-27
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• 2005

As home network is increasing to use, home network industry is developing too. Also, it is to be a popular subject in the network's topics. In this reasons, home network become a important thing because home gateway function is working between access network and home network. In the home network, it relates on the personal computer, home pad, and digital television. But, home gateway is not prepared standard point about techniques. Therefore, many kind of technique want to try for developing of home gateway's functions. Usually, we use ID/PASSWORD method in network control system. But, we found a lot of problems about classical network system while we experienced Jan/25 big trouble. We are considering about that home network system are using same network net. Therefore, seriously we have to check about security and safety at the home network's environment. This report focus on the home network's environment to control for using and efficiency and then it wants to find ways to protect from the internal and external attacks. Existing ID/PASSWORD method it used a electronic signature and the security against the approach from of external watch, the MIB structure of role base and the security of the Home network which leads the authority control which is safe even from the Home network inside it strengthened it used compared to it proposed.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.33-42
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• 1999

Geometrically standardized dental radiographs were taken. We prepared Digital Cu-Equivalent Image Analyzing System for quantitative assessment of mandible bone. Images of radiographs were digitized by means of Quick scanner and personal Mcquintosh computer. NIH image as software was used for analyzing images. A stepwedge composed of 10 steps of 0.1mm copper foil in thickness was used for reference material. This study evaluated the effects of step numbers of copper wedge adopted for calculating equation. kVp and exposure time on the coefficient of determination(r²)of the equation for conversion to Cu-equivalent image and the coefficient of variation and Cu-Eq value(mm) measured at each copper step and alveolar bone of the mandible. The results were as follows: 1. The coefficients of determination(r²) of 10 conversion equations ranged from 0.9996 to 0.9973(mean=0.9988) under 70kVp and 0.16 sec. exposure. The equation showed the highest r was Y=4.75614612-0.06300524x +0.00032367x² -0.00000060x³. 2. The value of r² became lower when the equation was calculated from the copper stepwedge including 1.0mm step. In case of including 0mm step for calculation. the value of r showed variability. 3. The coefficient of variation showed 0.11, 0.20 respectively at each copper step of 0.2, 0.1mm in thickness. Those of the other steps to 0.9 mm ranged from 0.06 to 0.09 in mean value. 4. The mean Cu-Eq value of alveolar bone was 0.14±0.02mm under optimal exposure. The values were lower than the mean under the exposures over 0.20sec. in 60kVp and over 0.16sec. in 70kVp. 5. Under the exposure condition of 60kVp 0.16sec.. the coefficient of variation showed 0.03. 0.05 respectively at each copper-step of 0.3, 0.2mm in thickness. The value of r² showed over 0.9991 from both 9 and 10 steps of copper. The Cu-Eq value and the coefficient of variation was 0.14±0.01mm and 0.07 at alveolar bone respectively. In summary. A clinical application of this system seemed to be useful for assessment of quantitative assessment of alveolar provided high coefficient of determination is obtained by the modified adoption of copper step numbers and the low coefficient of variation for the range of Cu-Equivalent value of alveolar bone from optimal kVp and exposure time for each x-ray machine.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.89-94
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• 2006

Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7 mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.516-530
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• 1999

The current clinical technique for occlusal vertical dimension recording is based on marking the skin reference points on the patient's face and measuring between these points using caliper-like device. And it is difficult to achieve reliable measurements by this technique because of movable soft tissue. The purpose of this study is to reveal the stability of skin reference points by comparing the relative movement between extra-oral skin reference points and intra-oral reference points using X-ray fluoroscope. 10 test subjects were divided into 2 groups : Group I (natural dentition) and Group II (denture-wearer whose vertical dimension was lost) and Group III consists of identical test subjects to Group II with their upper denture removed and record base inserted. Attaching the 3 mm diameter steel ball to nose tip, lower lip, chin and to existing denture (or record base), fluoroscopic examination and recording were taken during 2 jaw opening and closing movements. After subsequent digitization using personal computer, 1219 still pictures with 0.1 second interval were made. Using the 2 dimensional graphic software, measurements between reference points were executed. Dividing the entire jaw movement into 3 ranges (total, 1st half opening, 2nd half opening), rate of movement and relative movement between extra-oral and intra-oral reference points were calculated and statistically analyzed. The results of this study are as follows. 1 Within the same experimental group, no statistical difference was found in the stability of skin reference between lower lip point and chin point during total range of jaw opening and closing movement (p>.05) 2. In the first half range of jaw opening, statistical difference was found between Group I (natural dentition) and Group II (denture wearer) (p<.05) Group I has greater skin reference stability than Group II. 3. In the first half range of jaw opening, statistical difference was found between Group I and Group III (record base wearer) (p<.05). Group I has greater skin reference stability than Group III. 4. In the first half range of jaw opening, no statistical difference was found in the stability of skin reference between Group II and Group III (p>.05). 5. In the second half range of jaw opening, no statistical difference was found in the stability of skin reference between any experimental groups (p>.05). 6. In patients with their occlusal vertical dimension lost, employing other measuring references rather than skin is recommended because of low stability.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.329-338
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• 2014

Today, one of the important factors that determine the university rating is the employment rate. The jobseekers are using online or offline recruiting services in order to get the desired job information. There are lots of employment supporting systems as like web-based employment agencies and University's job centers, but they are focusing more on providing job information rather than on managing the employment support. In addition, those are insufficient to support business process associated with MOU companies, industry field training, mentoring processors, etc., and to continue to manage and to update the information (resume, personal statement, etc.) about the students which the companies want, and the information about the companies which jobseekers want. Therefore, it is required that the employment supporting system which not only storages the initial data (student and corporate information), but also assist the career placement. In this paper, we considered the specific employment rights management features of the existing employment support system, it could receive real-time job information in the smart phone, we presented the design and construction of the system linked to the Bachelor Information System.

• The Korean Journal of Applied Statistics
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• v.30 no.4
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• pp.603-613
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• 2017

Many people have recently posted about personal interests on social media. The development of the Internet and computer technology has enabled the storage of digital forms of documents that has resulted in an explosion of the amount of textual data generated; subsequently there is an increased demand for technology to create valuable information from a large number of documents. A text mining technique is often used since text-based data is mostly composed of unstructured forms that are not suitable for the application of statistical analysis or data mining techniques. This study analyzed the Meteorological Yearbook data of the Korea Meteorological Administration (KMA) with a text mining technique. First, a term dictionary was constructed through preprocessing and a term-document matrix was generated. This term dictionary was then used to calculate the annual frequency of term, and observe the change in relative frequency for frequently appearing words. We also used regression analysis to identify terms with increasing and decreasing trends. We analyzed the trends in the Meteorological Yearbook of the KMA and analyzed trends of weather related news, weather status, and status of work trends that the KMA focused on. This study is to provide useful information that can help analyze and improve the meteorological services and reflect meteorological policy.

• The Journal of Korean Medicine
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• v.17 no.1 s.31
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• pp.302-328
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• 1996

I . Objective and significance of the study To design a data acquisition chart, which facilitates data collection and analysis. The chart is also useful for solving problems that arise from personal variations in clinical symptoms and filling the knowledge base of an expert system. II. Content and scope 1. Collect the diagnosis knowledge of cerebrovacular diseases from doctors and analyze it. 2. Design a data acquisition chart. 3. Compare ODS and doctors with respect to their diagnosis results 4. Select patients who are determined to suffer from cerebrovascular diseases using CT(computed tomographic) scan, collect clinical data from them. III. Results and Application The chart be used for data collection and analysis in different medical hospitals, The results of data analysis facilitates collecting clinical data about other diseases and implementing the knowledge base. Also, the collected data serves as a tool for medical education, and cooperative diagnosis of oriental and western medical doctors.