• Journal of Korea Multimedia Society
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• v.11 no.7
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• pp.956-965
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• 2008

H.264/AVC is the newest video coding standard of ITU-T VCEG and the ISO/IEC MPEG, offering a significant performance improvement over previous video coding standards. However, the computational complexity of H.264/AVC is drastically increased because of new technologies such as intra prediction, variable block size, quarter-pels motion estimation/compensation, etc. In this paper, we propose a fast intra prediction scheme which has two step processing. The first step is a fast block size decision which can be calculated only in one block without considering all cases of $4{\times}4$ block and $16{\times}16$ block. The complexity of the intra prediction can be reduced by using boundary difference values of macroblock. After selecting the block size, we can make mode decision using the neighbouring reference pixels and representative pixels of the block in the second step. The experimental results show that the proposed algorithm saved on the average 41.5% encoding time without any significant PSNR losses.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.75-78
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• 2001

본 논문은 통계청에서 실시하는 인구주택 총조사로부터 획득된 각 개인의 직업 및 직종을 기술하고 있는 자연어를 입력받아 입력된 자연어가 의미하는 한국 표준 산업/구업 분류 코드의 후보들을 생성하는 산업/직업 코드 분류 도구를 제안한다. 코드 분류는 분류할 코드를 문서 범주로 간주하면 문서 분류와 동일한 문제로 생각할 수 있다. 하지만 본 산업/직업 코드 분류 문제는 입력되는 자연어의 길이가 한 두 문장 정도로 매우 짧아 문서 분류에 사용될 자질들이 개수가 주어 기존의 문서 분류 기법을 적용하기 어렵다. 이에 본 논문은 표준 코드를 기술하고 있는 내용을 미리 색인하고 입력된 자연어로부터 질의어를 생성하여 벡터공간모델로 질의어를 검색후 질의어와 일치율이 가장 높은 코드들을 분류될 후보 코드로 계시하는 정보검색 기법을 이용한 산업/직업 코드 분류 도구를 개발하였다.

• Communications for Statistical Applications and Methods
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• v.16 no.4
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• pp.595-603
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• 2009

Typically the standard optimal allocation method distributes the sample for each stratum considering survey cost. In case of varying survey cost for each survey unit, we need to consider more practical allocation method. In other words, according to characteristics of an individual unit, we consider the optimal dynamic allocation method which first selects the survey unit having maximum value of benefit cost ratio. In terms of this, the proposed allocation method is different from standard optimal allocation method which allocate samples for each stratum and selects the random sample according to each size of sample. This paper is considered the dynamic optimal allocation method for the stratified randomized response technique which surveys for sensitive characteristic of survey units such as drug abuse, abortion, alcoholic. We prove the practical usefulness of proposed method using the numerical example.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.210-219
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• 2015

This paper describes a new quantitative process for evaluating the roughness of discontinuity, which is suggested as a qualitative criteria in RMR or Q-system. For this purpose, the Delphi method which is one of the surveying methods was introduced. The selected panels were asked to evaluate the roughness of discontinuities on the Web which was hosted by authors in advance. A total of 3 surveys were performed using JRCs suggested by Barton and Choubey as well as Ai generated by the Monte Carlo simulations. After each survey, the results were provided to all panels for comparing their decisions to others. As surveys proceeded, better consensus and convergence were achieved. With a good agreement of panels on roughness classification, the quantitative criteria for roughness of discontinuity in RMR and Q-system was established in this study.

• The Korean Journal of Applied Statistics
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• v.27 no.5
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• pp.667-679
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• 2014

National Health Insurance Service(NHIS) provide care-plans for beneficiaries in the long-term care insurance(LTCI) systems that help them use LTC services appropriately. The care-plan includes recommendations for the most adequate type of care (gold standard) for beneficiaries. This study develops a decision-support system to determine the appropriate type of care plan. To develop a model, we used a data set that well-trained assessors in the NHIS investigated as a gold standard for beneficiaries: nursing home care, home-visit care, home-visit bathing, home-visit nursing, or day and night care. The decision-support system was established through a decision-tree model, because it may be easy to explain the algorithm of a decision-support system to working groups and policy makers. Our results might be useful in evidence-based care planning in an LTCI system and contribute to the efficient use of LTC services.

• Journal of the Korean Society of Radiology
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• v.10 no.1
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• pp.21-28
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• 2016

This study tries to evaluate the usefulness CSI treatment. Compare the standard technique and simple technique, using the volume region of a high dose of Field joints (hot spot) or low dose regions (cold Spot). In patients who agreed to this study, obtain CT image using CT simulator skull to pelvis region. Standard Technique were performed on the movement of the joint radiation field range and simple technique has set a treatment plan to secure the radiation field range and analyzed treatment planning. Under analysis standard technique occurred the area of the high dose(Hot Spot) for the area overlapping the field and simple technique showing a uniform doses. CI indices of standard technique and simple technique was 1.6~3, 1.6~1.87, CN indices was 0.32~0.53, 0.46~0.51 and HI indices was 0.11~0.33, 0.2~0.26. Therefore, adjacent to part of the dose distribution junction more equally than simple technique compared to the Standard Technique. Compare the dose distribution patterns using CI, CN, HI indices, showed a uniform dose distribution in the simple technique. so, simple technique was determined appropriate treatment the CSI.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.792-801
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• 2016

Standard Penetration Test (SPT) and Cone Penetration Test (CPT) are widely used in geotechnical investigation methods for railway roadbed. However, SPT can not be used on the Railway track, since the equipment may contact to the electric lines. However, a portable equipment can be used for geotechnical investigation without electrical hazard. Dynamic Cone Penetrometer (DCP) is one of representative portable equipments. A normal portable DCP has usually not enough driving energy and the rigidity of cone-rod, so it is impossible to investigate the required investigate penetration depth. In this study, The adaptability of Pagani cone test which is one of portable dynamic cone penetrometer is studied and compared with SPT-N data. As a result of this study, the proposed correlation factors between Pagani cone test and SPT-N values after corrections is 1.48 for sandy soil and 1.33 for clayey soil.

• Proceedings of the KSRS Conference
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• 2001.03a
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• pp.77-81
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• 2001

2000년 4월, 강원도 삼척일대에 크게 발생한 산불지역에 대해서 Landsat TM 인공위성 영상자료를 이용하여 산불의 피해지역을 조사분석하였다. 산불발생 전과 후의 2시기 위성영상을 이용하여 변화탐지 기법의 하나인 화상간차이법을 적용하였다. 분석결과 산불 발생지역의 탐지에는 NDVI를 유도하고 그 차이를 이용하는 것이 가장 탁월한 것으로 나타났다. 산불 피해지역을 구분하는 임계값을 표준편차$\times$0.9로 하였을 때, 현지조사 결과에 대한 전체정확도는 93.8%, 카파계수는 0.82로 매우 높았다.

• Information and Communications Magazine
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• v.24 no.6
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• pp.67-75
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• 2007

최근 다양한 멀티미디어 응용 및 시나리오가 등장함에 따라 멀티캐스트 전송 기법의 중요성이 더욱 부각되고 있다. 본고에서는 무선랜의 MAC 계층 멀티캐스트 기법에 초점을 맞추어 현재 IEEE 802.11 표준에서 정의하는 멀티캐스트 기법은 어떻게 동작하며 그 한계점은 무엇인지 살펴본다. 그리고 본고에서 명시된 문제점을 해결하기 위하여 활용 가능한 IEEE 802.11 무선랜 MAC 계층의 다양한 멀티캐스트 기법 중 대표적인 관련 연구들과 그 문제점을 함께 알아본다. 마지막으로 효율적인 IEEE 802.11 MAC 계층 멀티캐스트 기법을 설계할 때 고려해야 할 요구 사항을 정리한다.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.163-170
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• 2001

Purpose : The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Materials and Methods : Four human cancer cell lines - PCI-1, SNU-1066, NCI-H630 and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy. For clonogenic assay, cells in $25\;cm^2$ flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for $10\~14$ days. For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. Results : There was minimal variation in the values gained from these two methods with the standard deviation generally less than $5\%$, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the $R^2$ value of $0.975\~0.992$ between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than $30\%$). For cells with low plating efficiency (less than $30\%$), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was after 6 doubling times for the results compatible with those of clonogenic assay, at least after 4 doubling times was required for valid results. In consideration of practical limits of assay (12 days, in this study) cells with doubling time more than 3 days were inappropriate for application. Conclusion : In conclusion, it is found that MTT assay can successfully replace clonogenic assay of tested cancer cell lines after irradiation only if MTT assay was undertaken with optimal assay conditions that included plating efficiency of each cell line and doubling time at least.