• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.93-99
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• 2003

Various attempts have been made to explain the: pronounced seasonal and universal time (UT) variations of geomagnetic indices. As one of such attempts, we analyze the hourly-averaged auroral electroject indices obtained during the past 20 years. The AU and AL indices maximize during summer and equinoctial months, respectively. By normalizing the contribution of the solar conductivity enhancement to the AU index, or to the eastward electrojet, it is found that the AU also follows the same semiannual variation pattern of the AL index, suggesting that the electric field is the main modulator of the semiannual magnetic variation. The fact that the variation pattern of the yearly-mean AU index follows the mirror image of the AL index provides another indication that the electric field is the main modulator of magnetic disturbance. The pronounced UT variations of the auroral electrojet indices are also noted. To determine the magnetic activity dependence, the probability of recording a given activity level of AU and AL during each UT is examined. The UT variation of the AL index, thus obtained, shows a maximum at around 1200-1800 UT and a minimum around 0000-0800 UT particularly during winter. It is closely associated with the rotation of the geomagnetic pole around the rotational axis, which results in the change of the solar-originated ionospheric conductivity distribution over the polar region. On the other hand the UT variation is prominent during disturbed periods, indicating that the latitudinal mismatch between the AE stations and the auroral electrojet belt is responsible for it. Although not as prominent as the AL index, the probability distribution of the AU also shows two UT peaks. We confirm that the Dst index shows more prominent seasonal variation than the AE indices. However, the UT variation of the Dst index is only noticeable during the main phase of a magnetic storm. It is a combined result of the uneven distribution of the Dst stations and frequent developments of the partial ring current and substorm wedge current preferentially during the main phase.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.467-473
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• 2005

Calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized and accepted as a standard procedure. One of the commonly reported problems of calvarial bone graft is the contour defect caused by partial resorption of the graft. But, there are few reports that discuss the fate of the calvarial bone graft based on the quantitative data. In this article, the changes of grafted calvarial bone were evaluated using 3-dimensional computed tomography(CT). 9 patients were observed with the CT scans at 2mm thickness immediately after operation and at the time of last follow-up. The area of the bone defect was segmented on the 3-dimensional CT image and calculated by AnalyzeDirect 5.0 software. The immediate postoperative bone defect area of the recipient site and the donor site were $612.9mm^2$ and $441.5mm^2$, respectively, which became $1028.1mm^2$ and $268.8mm^2$, respectively at the last follow-up. In conclusion, the bone defect area was less increased on the donor site of calvarial bone graft than on the recipient site. And the CT scan is a valuable imaging method to assess and follow-up the clinical outcome of calvarial bone grafting.

• The Korean Journal of Pain
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• v.29 no.3
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• pp.185-188
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• 2016

The $12^{th}$ rib syndrome is a disease that causes pain between the upper abdomen and the lower chest. It is assumed that the impinging on the nerves between the ribs causes pain in the lower chest, upper abdomen, and flank. A 74-year-old female patient visited a pain clinic complaining of pain in her back, and left chest wall at a 7 on the 0-10 Numeric Rating scale (NRS). She had a lateral fixation at T12-L2, 6 years earlier. After the operation, she had multiple osteoporotic compression fractures. When the spine was bent, the patient complained about a sharp pain in the left mid-axillary line and radiating pain toward the abdomen. On physical examination, the $10^{th}$ rib was not felt, and an image of the rib-cage confirmed that the left $10^{th}$ rib was severed. When applying pressure from the legs to the $9^{th}$ rib of the patient, pain was reproduced. Therefore, the patient was diagnosed with $9^{th}$ rib syndrome, and ultrasound-guided $9^{th}$ and $10^{th}$ intercostal nerve blocks were performed around the tips of the severed $10^{th}$ rib. In addition, local anesthetics with triamcinolone were administered into the muscles beneath the $9^{th}$ rib at the point of the greatest tenderness. The patient's pain was reduced to NRS 2 point. In this case, it is suspected that the patient had a partial resection of the left $10^{th}$ rib in the past, and subsequent compression fractures at T8 and T9 led to the deformation of the rib cage, causing the tip of the remaining $10^{th}$ rib to impinge on the $9^{th}$ intercostal nerves, causing pain.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.632-642
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• 2005

This paper presents a new vertex selection scheme for the polygon-based contour approximation. In the proposed method, the entire contour is partitioned into partial segments and they are approximated adaptively with variable accuracy. The approximation accuracy of each segment is controlled based on its relative significance. By computing the relative significance with the texture degradation in the approximation error region, the visual quality enhancement in the reconstructed frames can be achieved under the same amount of the contour data. For this purpose, a decision rule for $d_{max}$ is derived based on inter-region contrasts. In addition, an adaptive vertex selection method using the derived rule is proposed. Experimental results are presented to show the superiority of the proposed method over conventional methods.

• Journal of the Korean Society for information Management
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• v.32 no.3
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• pp.377-396
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• 2015

This study proposed a key-frame automatic extraction method for video storyboard surrogates based on users' cognitive responses, EEG signals and discriminant analysis. Using twenty participants, we examined which ERP pattern is suitable for each step, assuming that there are five image recognition and process steps (stimuli attention, stimuli perception, memory retrieval, stimuli/memory comparison, relevance judgement). As a result, we found that each step has a suitable ERP pattern, such as N100, P200, N400, P3b, and P600. Moreover, we also found that the peak amplitude of left parietal lobe (P7) and the latency of FP2 are important variables in distinguishing among relevant, partial, and non-relevant frames. Using these variables, we conducted a discriminant analysis to classify between relevant and non-relevant frames.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.383-386
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• 2006

Several HTPB/AP and HTPB/AP/HMX propellants were investigated experimentally for ignition characteristics in subatmospheric pressure. The threshold ignition pressure was 4psia for HTPB/AP composite propellant. The partial replacement of AP in HTPB/AP composite propellant by $5\sim15%$ of HMX, HNIW showed improvements in the threshold pressure was below 0.4psia. This appears to be due to the exothermic dissociation characteristics of HMX and HNIW at lower temperature $(\sim220^{\circ}C)$ than that of AP. The ignition substance B/KNO3 was coated thinly on the propellant surface for better ignition effect. As a result, ignition delay time of 15% was improved. NC is applied to $B/KNO_3$ ignition substance as a secondary binder and $NC-B/KNO-3$ suspension solution is coated to the propellant surface.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.1 s.343
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• pp.79-84
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• 2006

This paper proposed a novel H.264 deblocking filter for low-power mobile multimedia SoCs. In H.264 deblocking filter, filtering can be skipped on some pixels when pixel value differences satisfy some specific conditions. Furthermore, whole filtering can be skipped when quantization parameter is less than 16. Based on these features, power consumption can be significantly reduced by shutting down deblocking filter partially or as a whole. The proposed deblocking filter can shut down partial or whole blocks with simple control circuits. Common hardware performs both horizontal filtering and vertical filtering. It was implemented in silicon chip using $0.35{\mu}m$ standard cell library technology. The gate count is about 20,000 gates. The maximum operation frequency is 108MHz. The maximum throughput is 30 frame/s with CCIR601 image format.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1433-1443
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• 1993

DCT(Discrete Cosine Transform) / IDCT(Inverse DCT) is widely used in various image compression and decompression systems as well as in DSP(Digital Signal Processing) applications. Since DCT/ IDCT is one of the most complicated part of the compression system, the performance of the system can be greatly enchanced by improving the speed of DCT/IDCT operation. In this thesis, we designed a DCT/IDCT core processor using module generator technique. By utilizing the partial sum and DA(Distributed Arithmetic) techniques, the DCT/ IDCT core processor is designed within small area. It is also designed to perform the IDCT(Inverse DCT) operation with little additional circuitry. The pipeline structure of the core processor enables the high performance, and the high accuracy of the DCT/IDCT operation is obtained by having fewer rounding stages. The proposed design is independent of design rules, and the number of the input bits and the accuracy of the internal calculation coa be easily adjusted due to the module generator technique. The accuracy of the processor satisfies the specifications in CCITT recommendation H, 261.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.1
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• pp.42-55
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• 2017

Since the phases and patterns of the climate adaptability of vegetation can greatly differ from region to region, an intensive pixel scale approach is required. In this study, Partial Least Squares (PLS) regression on satellite image-based vegetation index is conducted for to assess the effect of climate factors on vegetation productivity and to predict future productivity of forests vegetation in South Korea. The results indicate that the mean temperature of wettest quarter (Bio8), mean temperature of driest quarter (Bio9), and precipitation of driest month (Bio14) showed higher influence on vegetation productivity. The predicted 2050 EVI in future climate change scenario have declined on average, especially in high elevation zone. The results of this study can be used in productivity monitoring of climate-sensitive vegetation and estimation of changes in forest carbon storage under climate change.

• The Journal of Korean Association of Computer Education
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• v.10 no.2
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• pp.1-8
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• 2007

Although the core of national competitiveness in the knowledge information society lies in IT, school education at the moment is failing to execute systematic and organized computer education. Recently, the 7th on-demand partial amendment of educational curriculum at national level is being executed in full-scale. Educational curriculum for elementary and middle class at national level is the systematic and organized program for cultivation of competent persons in order to foster the desired image of human kind for the future society pursued by the nation. For such reason, stabilization of program for cultivation of competent persons for establishment of true IT superpower is not irrelevant with the 7th amendment of the educational curriculum. Therefore, this thesis shall look into the 7th national level education curriculum at level of general outline as well as their particulars, and present means of amendment of computer subject educational curriculum through the means connecting the issues raised in general outline and their particulars regarding the direction of the amendment of the national level educational curriculum for establishment of true IT superpower.