• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.150-159
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• 2014

The latest video coding standard, HEVC can improve the coding efficiency significantly compared with the H.264/AVC. However the HEVC encoder requires much larger computational complexities. The longer 8-tap interpolation filter of the HEVC which is used in a non-integer motion estimation is one of the reasons and this paper aims to reduce the computational complexities. First of all, three shorter-tap interpolation filters for a motion estimation process are tested rather than the use of a standard interpolation filter. In addition, the fast searching strategies to reduce the number of comparisons for choosing the best non-integer motion vector are proposed. Finally, the interpolation process is selectively applied according to the searching strategy. By combining all of the techniques, the experimental results show that the encoding times can be reduced by 13.6%, 18.5% and 21.1% with the coding efficiency penalties of 0.7%, 1.5% and 2.5%, respectively. For the full-HD video sequences, the coding efficiency penalties are reduced to 0.4%, 1.1% and 1.6% at the same level of the encoding time savings, which shows the effectiveness of the proposed schemes for the high resolution video sequences.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.97-104
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• 2017

In this paper, we designed and fabricated the multi band Transceiver Assembly(TCA) for the Multi Channel Synthetic Aperture Radar(MCSAR) containing C-band, X-band, Ku-band and we researched to verify electrical performance of TCA. The transceiver consists of transmitters, receivers, signal selection modules for each band, and stability oscillator, frequency synthesizer, controller, power distributor. The transceiver has a receive path selection and bandwidth selection functions in accordance with the operating mode. And the transceiver can transmit and receive all three bands simultaneously, each band has a bandwidth of up to 300 MHz. Final transmission output of transceiver for each band is over 20 dBm to be suitable for driving the T/R module. Receiver bandwidth is selected according to the required function and receiver gain has approximately C-band 52 dB, X-band 50 dB, Ku-band 60 dB, the maximum noise figure of Ku-band V polarization is 4.28 dB in the whole band H, V polarization. As a result of the electrical performance test, a multi-band TCA is satisfied the property requirements of the MCSAR.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.95-111
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• 2021

As the population decreases in an aging society, the average age of drivers increases. Accordingly, the elderly at high risk of being in an accident need autonomous-driving vehicles. In order to secure driving safety on the road, several technologies to respond to various obstacles are required in those vehicles. Among them, technology is required to recognize static obstacles, such as poor road conditions, as well as dynamic obstacles, such as vehicles, bicycles, and people, that may be encountered while driving. In this study, we propose a deep neural network algorithm capable of simultaneously detecting these two types of obstacle. For this algorithm, we used 1,418 road images and produced annotation data that marks seven categories of dynamic obstacles and labels images to indicate road damage. As a result of training, dynamic obstacles were detected with an average accuracy of 46.22%, and road surface damage was detected with a mean intersection over union of 74.71%. In addition, the average elapsed time required to process a single image is 89ms, and this algorithm is suitable for personal mobility vehicles that are slower than ordinary vehicles. In the future, it is expected that driving safety with personal mobility vehicles will be improved by utilizing technology that detects road obstacles.

• Journal of the Korean Society of Radiology
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• v.9 no.6
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• pp.343-348
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• 2015

The purpose of this study is a comparison of forward planning(FP) and inverse planning(IP) of a radiosurgery procedure. 10 patients of acoustic schwannoma MR image were used for treatment plan. FP-1,2 and IP were established under the same condition. FP and IP were compared by number of shot, conformity index(CI), paddic conformity index(PCI), gradiant index(GI) and treatment time. On average the treatment plan produced by IP tool provided an improved or similar CI, PCI, GI and reduced treatment time as compared to the FP (CI;FP-1:0.85, FP-2:0.86, IP:0.94, PCI;FP-1:0.79, FP-2:0.81, IP:0.78, GI;FP-1:2.94, FP-2:2.94, IP:3.01). The inverse planning system provides a clinically useful plan while reducing the planning time and treatment time.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.2
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• pp.315-322
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• 1993

To evaluate of the relationship between the TMJ disorder and the vertical mandibular asymmetry, the author analyzed the differences between condylar heights, ramus heights and mandibular heights of both sides. All measurements were performed with a digital micrometer on the panoramic radiographs of 36 TMJ disorder patients and 30 normal control group. The differences were expressed in millimeters and percentage using the following formula; ｜(R-L)/(R+L)｜×100% The results were as follows : 1. The condylar height difference was greater of in patient group (1.86±1.66㎜) than that of in control group (1.22±0.85㎜)(p<0.05). But there was no significant difference in the condylar height ratio difference between patient group (11.67㎜11.44%) and control group (7.64±621%) (p>0.05). 2. The ramus height difference and ramus height ratio difference of patient group (4.52±3.70㎜, 4.39±3.49%) were greater than those of control group (2.64±2.13㎜, 2.46±2.02%)(p<0.05, p<0.01). 3. The mandibular height difference and mandibular height ratio difference of patient group (4.32±3.52㎜, 3.59±2.81%) were greater than those of control group (2.57±2.46㎜, 2.01±1.95%) (p<0.05). 4. The ratio difference in condylar height to ramus height and condylar height to mandibular height of patient group (5.01±4.13%, 3.36±2.88%) were greater than those of control group (2.33±1.78%, 1.90±1.40%) (p<0.01).

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.1-13
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• 2006

Three-dimensional (3-D) laser scans can provide a 3-D image of the face and it is efficient in examining specific structures of the craniofacial soft tissues. Due to the increasing concerns with the soft tissues and expansion of the treatment range, a need for 3-D soft tissue analysis has become urgent. Therefore, the purpose of this study was to evaluate the scanning error of the Vivid 900 (Minolta, Tokyo, Japan) 3-D laser scanner and Rapidform program (Inus Technology Inc., Seoul, Korea) and to evaluate the mean error and the magnification percentage of the image obtained from 3-D laser scans. In addition, soft tissue landmarks that are easy to designate and reproduce in 3-D images of normal, Class II and Class III malocclusion patients were obtained. The conclusions are as follows; scanning errors of the Vivid 900 3-D laser scanner using a manikin were 0.16 mm in the X axis, 0.15 mm in the Y axis, and 0.15 mm in the Z axis. In the comparison of actual measurements from the manikin and the 3-D image obtained from the Rapidform program, the mean error was 0.37 mm and the magnification was 0.66%. Except for the right soft tissue gonion from the 3-D image, errors of all soft tissue landmarks were within 2.0 mm. Glabella, soft tissue nasion, endocanthion, exocanthion, pronasale, subnasale, nasal alare, upper lip point, cheilion, lower lip point, soft tissue B point, soft tissue pogonion, soft tissue menton and preaurale had especially small errors. Therefore, the Rapidform program can be considered a clinically efficient tool to produce and measure 3-D images. The soft tissue landmarks proposed above are mostly anatomically important points which are also easily reproducible. These landmarks can be beneficial in 3-D diagnosis and analysis.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1479-1488
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• 2018

On September 3rd 2017, strong artificial seismic signals from North Korea were detected in KMA (Korea Meteorological Administration) seismic network. The location of the epicenter was estimated to be Punggye-ri nuclear test site and it was the most powerful to date. The event was not studied well due to accessibility and geodetic measurements. Therefore, we used remote sensing data to analyze surface changes around Mt. Mantap area. First of all, we tried to detect surface deformation using InSAR method with Advanced Land Observation Satellite-2 (ALOS-2). Even though ALOS-2 data used L-band long wavelength, it was not working well for this particular case because of decorrelation on interferogram. The main reason would be large deformation near the Mt. Mantap area. To overcome this limitation of decorrelation, we applied offset tracking method to measure deformation. However, this method is affected by window kernel size. So we applied various window sizes from 32 to 224 in 16 steps. We could retrieve 2D surface deformation of about 3 m in maximum in the west side of Mt. Mantap. Second, we used Pleiadas-A/B high resolution satellite optical images which were acquired before and after the 6th nuclear test. We detected widespread surface damage around the top of Mt. Mantap such as landslide and suspected collapse area. This phenomenon may be caused by a very strong underground nuclear explosion test. High-resolution satellite images could be used to analyze non-accessible area.

• Phonetics and Speech Sciences
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• v.10 no.1
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• pp.57-64
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• 2018

The purpose of the present study was to explore the radiological and acoustic characteristics of "Arae-a" (/${\cdot}$/) articulation in two male Jeju language speakers, focusing on selected measures in radiological images derived from computed tomography scans, as well as the first and the second formant measures in selected vowels. An elderly male speaker (a 78-year-old) and a young male speaker (a 34-year-old) participated in the study. During the production of four selected vowels, the shape of the vocal tract was identified, and selected measures were obtained from the elderly participant's computed tomography (CT) scans. For acoustic analysis, the participants were given a list of near-minimal pairs consisting of 112 words and asked to read them aloud. The results indicated that the "Arae-a" (/${\cdot}$/) articulation of the elderly speaker showed unique acoustic and radiological characteristics compared to other similar vowels, thus presenting substantial consistency with the descriptions of the "Hunminjeongeum Haeryebon." In contrast, the F1 and F2 measures of the young male's /${\cdot}$/ articulation were not distinguished from those of /ㅗ/. Current results, in part, support the scientific principles underlying the invention of "Arae-a," which reflects the shape of the vocal tract during production, and the necessity for further research.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.81-86
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• 2015

We fabricated a 3D knee joint model through the imaging processing. The 3D shape information is different depends on specific conditions when the shape of real knee joint is extracted from CT/MRI sliced images. The two types of joint models were fabricated by using 3D printer in order to analysis of joint movement by slight difference of 3D shape information. The compressive force experiments were performed by using knee joint model. As the results, the compressive forces were changed with respect to the difference of geometry. Consequently, feasibility test should be performed before developing biomimetic bioreactor.

• Imaging Science in Dentistry
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• v.31 no.3
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• pp.153-158
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• 2001

Purpose : To determine the head position that the superior border of the mandibular canal as well as mental foramen can be more clearly visualized in panoramic radiography Materials and Methods : Ten dry mandibles were radiographed bilaterally using PM 2002 CC panoramic machine. A 20 mm thick aluminium filter was added to the slit collimator to obtain radiographs with acceptable density. The specimens were tilted by 2, 4, 6, 8, and 10 degrees downward with and without radiopaque markers. Radiopaque markers were inserted into the mandibular canals and the mental canals of each side of the specimens to serve as reference image when assessing the radiographs. The visibility of the mandibular canal and the mental foramen was estimated by 4 observers on all radiographs. The obtained results were analyzed statistically. Results: Mandibular canals were significantly more clearly visible in the radiographs with 4 and 6 degree downward position on both sides (P<0.05). Mental foramens were significantly more clearly visible in the radiographs with 4, 6, and 8 degree downward on right side and 6 degree downward on left side (P<0.05). There was not significant difference between right and left sides. Conclusion: Panoramic radiographs with 4 to 6 degree downward tilting could be valuable in locating the mandibular canal as well as the mental foramen.