• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.82-98
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• 2019

The importance of spatial information is rapidly rising. In particular, 3D spatial information construction and modeling for Real World Objects, such as smart cities and digital twins, has become an important core technology. The constructed 3D spatial information is used in various fields such as land management, landscape analysis, environment and welfare service. Three-dimensional modeling with image has the hig visibility and reality of objects by generating texturing. However, some texturing might have occlusion area inevitably generated due to physical deposits such as roadside trees, adjacent objects, vehicles, banners, etc. at the time of acquiring image Such occlusion area is a major cause of the deterioration of reality and accuracy of the constructed 3D modeling. Various studies have been conducted to solve the occlusion area. Recently the researches of deep learning algorithm have been conducted for detecting and resolving the occlusion area. For deep learning algorithm, sufficient training data is required, and the collected training data quality directly affects the performance and the result of the deep learning. Therefore, this study analyzed the ability of detecting the occlusion area of the image using various image quality to verify the performance and the result of deep learning according to the quality of the learning data. An image containing an object that causes occlusion is generated for each artificial and quantified image quality and applied to the implemented deep learning algorithm. The study found that the image quality for adjusting brightness was lower at 0.56 detection ratio for brighter images and that the image quality for pixel size and artificial noise control decreased rapidly from images adjusted from the main image to the middle level. In the F-measure performance evaluation method, the change in noise-controlled image resolution was the highest at 0.53 points. The ability to detect occlusion zones by image quality will be used as a valuable criterion for actual application of deep learning in the future. In the acquiring image, it is expected to contribute a lot to the practical application of deep learning by providing a certain level of image acquisition.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.3
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• pp.247-262
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• 2022

In domestic tunnels, it is mandatory to install CCTVs in tunnels longer than 200 m which are also recommended by installation of a CCTV-based automatic accident detection system. In general, the CCTVs in the tunnel are installed at a low height as well as near by the moving vehicles due to the spatial limitation of tunnel structure, so a severe perspective effect takes place in the distance of installed CCTV and moving vehicles. Because of this effect, conventional CCTV-based accident detection systems in tunnel are known in general to be very hard to achieve the performance in detection of unexpected accidents such as stop or reversely moving vehicles, person on the road and fires, especially far from 100 m. Therefore, in this study, the region of interest is set up and a new concept of inverse perspective transformation technique is introduced. Since moving vehicles in the transformed image is enlarged proportionally to the distance from CCTV, it is possible to achieve consistency in object detection and identification of actual speed of moving vehicles in distance. To show this aspect, two datasets in the same conditions are composed with the original and the transformed images of CCTV in tunnel, respectively. A comparison of variation of appearance speed and size of moving vehicles in distance are made. Then, the performances of the object detection in distance are compared with respect to the both trained deep-learning models. As a result, the model case with the transformed images are able to achieve consistent performance in object and accident detections in distance even by 200 m.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.565-578
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• 2000

The aim of this study was development of the Straight-Wire Appliance(SWA) suitable lot the treatment or Korean. To accomplish the object of this study, Korean adult with normal occlusion were selected with following criteria : 1) no functional abnormality in the craniofacial area, 2) good dental arch form and posterior occlusal relationship, 3) Angle Class I occlusal relationship, 4) no experience of orthodontic, nor prosthodontic treatment, especially, no dental treatment on labial and buccal surfaces of teeth, 5) good racial profile. Impression were taken for upper and lower dental arches or the selected normal occlusion samples and the orthodontic dental stone models were fabricated. 5 well-trained orthodontists had examined the acquired dental stone models to select study samples which satisfy the Six keys to optimal occlusion of Andrews. 155 pairs of dental stone models (92 pairs of Male, 63 of Female) were finally selected. 3 dimensional digitization were performed with the Coordinate Measuring Machine(CMM, MPC802, WEGU-Messtechnik, Germany) and measuring of Angulation, Inclination, In-and-Out, Molar offset angle and Arch form were accomplished with a measuring software to achieve data for the development of SWA. Before the measurement, error study was performed on the 3 dimensional digitization with CMM, and the analysis of reliability of computerized measuring method adapted in this study and conventional manual method Presented by Andrews was performed. Results of this study were as to)lows : 1. Equi-distance digitization with mesh size 0.25 mm, 0.5 mm and 1.0 mm were acceptable in 3 dimensional digitization of dental stone model with the CMM, and the digitization with 1.0 mm mesh size was recommendable in terms of efficiency. 2. Computerized measuring method with 3 dimensional digitization was more reliable than manual measuring method of Andrews. 3. Data were collected for the development of SWA suitable for the morphological characteristics of Korean with the computerized measuring method with 3 dimensional digitization.

• Journal of Korean Foot and Ankle Society
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• v.20 no.4
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• pp.163-169
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• 2016

Purpose: To investigate the measured values of the talus in Koreans. Materials and Methods: We measured 88 tali from 44 cadavers that have been donated between December 2012 and December 2015. Of the cadavers, 27 were male and 17 were female. Their mean age was 73 years. The length and width of the talus were measured using a digital goniometer and vernier caliper. Results: The values of cadaveric measurement, mean maximal width and length, width and length of the dome anterior, width and length of the posterior facet, height and length of the trochlear medial facet, and height and length of the trochlear lateral facet were $43.6{\pm}2.6mm$, $56.5{\pm}3.3mm$, $32.5{\pm}2.0mm$, $42.2{\pm}2.7mm$, $22.2{\pm}2.2mm$, $34.7{\pm}2.0mm$, $15.3{\pm}1.3mm$, $33.3{\pm}2.9mm$, $25.3{\pm}3.3mm$, and $30.8{\pm}2.4mm$ for men and $38.9{\pm}1.6mm$, $53.6{\pm}2.4mm$, $27.9{\pm}2.1mm$, $37.4{\pm}3.2mm$, $20.6{\pm}0.8mm$, $31.9{\pm}1.2mm$, $13.6{\pm}2.6mm$, $28.4{\pm}2.5mm$, $24.9{\pm}2.1mm$, and $28.9{\pm}1.4mm$ for women, respectively. The size of the talus showed an accuracy of 86% when anteroposterior diameter was greater than 59 mm. A difference in the size of the right and left talus was not observed. The mean inclination and declination angles were $24.4^{\circ}{\pm}4.2^{\circ}$ and $28.2^{\circ}{\pm}5.4^{\circ}$ for men, and $24.6^{\circ}{\pm}3.6^{\circ}$ and $24.7^{\circ}{\pm}6.7^{\circ}$ for women (p=0.980, p=0.018), respectively, at least $15^{\circ}$, which showed a big difference for every object up to $37^{\circ}$. Conclusion: This paper, to the best of our knowledge, is the first study to measure the talus in Koreans. There were differences by gender and ethnicity in the in measured talus values. The measurements were smaller than European-Americans and greater than Japanese.

• Progress in Medical Physics
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• v.23 no.2
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• pp.81-90
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• 2012

The effect of setup uncertainties on CTV dose and the correlation between setup uncertainties and setup margin were evaluated by Monte Carlo based numerical simulation. Patient specific information of IMRT treatment plan for rectal cancer designed on the VARIAN Eclipse planning system was utilized for the Monte Carlo simulation program including the planned dose distribution and tumor volume information of a rectal cancer patient. The simulation program was developed for the purpose of the study on Linux environment using open source packages, GNU C++ and ROOT data analysis framework. All misalignments of patient setup were assumed to follow the central limit theorem. Thus systematic and random errors were generated according to the gaussian statistics with a given standard deviation as simulation input parameter. After the setup error simulations, the change of dose in CTV volume was analyzed with the simulation result. In order to verify the conventional margin recipe, the correlation between setup error and setup margin was compared with the margin formula developed on three dimensional conformal radiation therapy. The simulation was performed total 2,000 times for each simulation input of systematic and random errors independently. The size of standard deviation for generating patient setup errors was changed from 1 mm to 10 mm with 1 mm step. In case for the systematic error the minimum dose on CTV $D_{min}^{stat{\cdot}}$ was decreased from 100.4 to 72.50% and the mean dose $\bar{D}_{syst{\cdot}}$ was decreased from 100.45% to 97.88%. However the standard deviation of dose distribution in CTV volume was increased from 0.02% to 3.33%. The effect of random error gave the same result of a reduction of mean and minimum dose to CTV volume. It was found that the minimum dose on CTV volume $D_{min}^{rand{\cdot}}$ was reduced from 100.45% to 94.80% and the mean dose to CTV $\bar{D}_{rand{\cdot}}$ was decreased from 100.46% to 97.87%. Like systematic error, the standard deviation of CTV dose ${\Delta}D_{rand}$ was increased from 0.01% to 0.63%. After calculating a size of margin for each systematic and random error the "population ratio" was introduced and applied to verify margin recipe. It was found that the conventional margin formula satisfy margin object on IMRT treatment for rectal cancer. It is considered that the developed Monte-carlo based simulation program might be useful to study for patient setup error and dose coverage in CTV volume due to variations of margin size and setup error.

• Journal of vocational education research
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• v.37 no.2
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• pp.39-75
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• 2018

The purpose of this study is to verify the general characteristics in the previous studies and the magnitude of the correlation between the learner's satisfaction and the academic achievement in the education and training program. To do this, we searched relevant literature from 2000 to 2016, and conducted a systematic review of the literature on the final 31 studies through the selection criteria and quality evaluation. Among them, 27 meta-analysis of the literature was conducted. The finding of the study were as follows. First, a total of 31 studies were conducted from 2000 to 2016, and more than half of them(16) were conducted for the last 4 years(2009~2012). In terms of education and training students, there are 18 college students, 9 workers, and 4 elementary students in order of study. In terms of methods, 15 collective education, 14 distance education, 2 blended education. In terms of learner's participation, 22 the general participation, 9 the active participation. Second, as a result of the meta-analysis, the magnitude of the correlation between satisfaction and achievement was moderate(ZCOR=.297, 95%: CI .210~.383). Third, as a result of verifying the difference in the magnitude of the correlation effect between satisfaction and achievement according to the characteristics of the education and training program, there was no difference between the groups in the student object and education method, but there was a difference in the magnitude of the correlation effect depending on the participant type(Q=15.40, df=1, p<.0001). The active participation showed a correlation effect size larger(ZCOR=.588, 95%: CI .422~.754). The effect size of the general participation was lower than the median(ZCOR=.211, 95%: CI .12 ~.300).

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.305-322
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• 2005

Watermarking is a widely employed method tn protecting copyright of a digital image, the owner's unique image is embedded into the original image. Strengthened level of watermark insertion would help enhance its resilience in the process of extraction even from various distortions of transformation on the image size or resolution. However, its level, at the same time, should be moderated enough not to reach human visibility. Finding a balance between these two is crucial in watermarking. For the algorithm for watermarking, the predefined strength of a watermark, computed from the physical difference between the original and embedded images, is applied to all images uniformal. The mean brightness or contrast of the surrounding images, other than the absolute brightness of an object, could affect human sensitivity for object detection. In the present study, we examined whether the detectability for watermark noise might be attired by image statistics: mean brightness and contrast of the image. As the first step to examine their effect, we made rune fundamental images with varied brightness and control of the original image. For each fundamental image, detectability for watermark noise was measured. The results showed that the strength ot watermark node for detection increased as tile brightness and contrast of the fundamental image were increased. We have fitted the data to a regression line which can be used to estimate the strength of watermark of a given image with a certain brightness and contrast. Although we need to take other required factors into consideration in directly applying this formula to actual watermarking algorithm, an adaptive watermarking algorithm could be built on this formula with image statistics, such as brightness and contrast.

• Journal of the Korean Geographical Society
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• v.28 no.3
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• pp.247-267
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• 1993

According to developing international economy since the World War II, the increase and competition of the national business is so empha-sized tht both the interest and the necessity about marine transportation playing the impor-thant role of international transportation are increased. Today, the container transportation, as called the innovation of marine transport has been prevailed since the 1970's. The purpose of this paper is to grasp the spatial structure of the hinterlands and forelands, its object is export container cargo at Pusan Export Port, as known for the transportation node of modern containerlization. In this study, for the purpose of grasping the relation between hinterlands and forelands of Korean export container cargo, first, I researched the transition of carloading about container cargo, the bistribution channel of cargo, the change of the items of container and the carlo-adings about transport route, secondly, I used the cluster analysis so as to group hinterlands according to the items of goods and forelands. The object of the analysis is container cargo of Choyang Line, Hanjin Shipping and Hyundai Merchant Marine of National Frag Carriers. The source materials used in this study are Trucking Data of Hanjin Co., Container Ren-tal Data of Samik Transport Co. and Transpor-ting Present Condition Tables of Hyundai Mer-chant Marine. 1. There are two kinds of the transport classi-fied by its form: FCL and LCL. In Pusan Con-tainer Export, a lot of textile goods, clothings and furniture, compound, electric goods, and so on are dealed with but the rate of occupation of the transport is getting lower while that of occupation of equipment, papers and agricultu-ral, mineral and livestock industry higher. 2. In 1990, the transports of container cargo in Korea consist of 7 services and round-the world lines. We can list North America lines, East-South Asian lines, Japan lines and Inter European lines, in order of the quantity of tran-sport form the largest to the smaller. We can have another list that Japan lines, North Ame-rica lines and East-South lines in order of the rate participation of national flag carriers, be-cacuse Korean foreign trade lay disproportionate emphasis on East-South Asian lines. Japan lines among them is the biggest import-export market. Since the rationlization policy of marine tran-sport in 1984, each of national flag carriers have its own lines. Hanjin Shipping predominates over North America lines, Choyang Line over New Zealand, Inter European and Austria lines and Hyundai Merchant Marine over Center-South America lines, in terms of the volume of transport. And small-to-medium sized shippers are prevailing in lines which are adjacent to Korea, Such as Japan lines and East-South Asian lines. 3. In relation to hinterlands and forelands of Choyang Line, the light industry goods, electric goods and machinary produced in Seoul and Pusan are exported to the major ports in Europe and Japan, the same produces in Suwon, Ulsan, Kumi are exported to European Ports, and those in Incheon and Kwangju Austrian and Japanese ports, and those in the rest regions to the major port in Japan. 4. In relation to hinterlands and forelands of Hanjin Shipping, the light industry goods pro-ducing in Seoul and Pusan, the electric goods and machinary in Incheon and Pyeongteck, are exported to New York and Los Angeles. Electric goods and machinary Masan, Anyang, Cheona, Cheongju and Incheon, Electric goods machinary and light industry goods in Kwangju and non mental goods in Pohang, are exported New York, Los Angeles and Oakland. 5. In relation to hinterlands and forelands of Hyundai Merchant Marine, the region of Seoul, Pusan and Incheon closely related with the main ports in U.S.A. The rest regions with Montreal. The hinterlands of export container cargo can be classified by its export items into three kinds: the large city, industrial city and the rest city. Choyang Line's forelands are European lines, Japan lines and Austria lines, and Hanjin Shipping's forelands are North America lines, and Hyundai Merchant Marine's forelands are North America lines and Japan line. 3 National flag carriers' major forelands are determined by the size of port and the shipper's convenient use of the port terminal.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.603-612
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• 2020

This study has a purpose to look into the effect of the relationship between the Tube current (mA) and SOD(Source to Object Distance), which is a parameter of lower limb angiography examination, and the dilution rate of the contrast medium concentration (300, 320, 350) on the image. To that end, using 3 mm vessel model water phantom, a vessel model custom made in the size of peripheral vessel diameter, this study measured relationships between change of parameters, such as tube current (mA), SOD and varying concentrations (300, 320, 350) of contrast medium dilution into SNR and CNR values while analyzing the coefficients of variance(cv<10). The software used to measure SNR and CNR values was Image J 1.50i from NIH (National Institutes of Health, USA). MPV (mean pixel value) and SD (standard deviation) were used after verifying numerically the image signal for region of interest (ROI) and background on phantom from the DICOM (digital imaging and communications in medicine) 3.0 file transmitted to PACS. As to contrast medium dilution by the change of tube current, when 146 mA and 102 mA were compared, For both SNR and CNR, the coefficient of variation value was less than 10 until the section of CM: N/S dilution (100% ~ 30% : 70%) but CM: N/S dilution rate (20%: 80% ~ 10% : 90%) the coefficient of variation was 10 or more. As to contrast medium dilution by concentration for SOD change, when SOD's (32.5 cm and 22.5 cm) were compared,For both SNR and CNR, the coefficient of variation value was less than 10 until the section of CM: N/S dilution (100% ~ 30% : 70%) but CM: N/S dilution rate (20%: 80% ~ 10% : 90%) the coefficient of variation was 10 or more. As to contrast medium dilution by concentration for SOD change, when SOD's (32.5 cm and 12.5 cm) were compared,For both SNR and CNR, the coefficient of variation value was less than 10 until the section of CM: N/S dilution (100% ~ 30% : 70%) but CM: N/S dilution rate (20%: 80% ~ 10% : 90%) the coefficient of variation was 10 or more. As a result, set a low tube current value in other tests or procedures including peripheral angiography of the lower extremities in the intervention, and make the table as close as possible to the image receiver, and adjust the contrast agent concentration (300) to CM: N/S dilution (30%: 70%). ) Is suggested as the most efficient way to obtain images with an appropriate concentration while simultaneously reducing the burden on the kidney and the burden on exposure.

• Tunnel and Underground Space
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• v.31 no.5
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• pp.374-384
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• 2021

In this study, we propose a new approach for automatic fracture detection in CT scan images of rock specimens. This approach is built on top of two-stage object detection deep learning algorithm called Faster R-CNN with a major modification of using rotated bounding box. The use of rotated bounding box plays a key role in the future work to overcome several inherent difficulties of fracture segmentation relating to the heterogeneity of uninterested background (i.e., minerals) and the variation in size and shape of fracture. Comparing to the commonly used bounding box (i.e., axis-align bounding box), rotated bounding box shows a greater adaptability to fit with the elongated shape of fracture, such that minimizing the ratio of background within the bounding box. Besides, an additional benefit of rotated bounding box is that it can provide relative information on the orientation and length of fracture without the further segmentation and measurement step. To validate the applicability of the proposed approach, we train and test our approach with a number of CT image sets of fractured granite specimens with highly heterogeneous background and other rocks such as sandstone and shale. The result demonstrates that our approach can lead to the encouraging results on fracture detection with the mean average precision (mAP) up to 0.89 and also outperform the conventional approach in terms of background-to-object ratio within the bounding box.