• Journal of Digital Contents Society
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• v.3 no.2
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• pp.221-233
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• 2002

In this paper, we present integer programming models and algorithms for the Capacitated Facility Location-Allocation Problem (CFLP). The models and algorithms can be used for the design of logistics networks and for the location of telecommunication facilities. We are given a set of candidate facility installation sites, one type of facility for each candidate site with its capacity and installation cost, a set of customers with their demand requirement, and flow cost for one unit of demand flow from each customer to each candidate site. (CFLP) is to determine the number of facilities for each candidate site and the set of customers which are connected to each site with minimum cost, while satisfying the demand requirement of each customer and constraints imposed on the allocation of customers to facilities. We present two integer programming models for (CFLP), and devise a branch-and-cut algorithm and a branch-and-price algorithm for the problem.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.77-83
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• 2015

Block Truncation Coding, or BTC, is a type of lossy image compression technique for grayscale images. It divides the original images into blocks and then reduces the number of grey levels in each block to compute the mean and standard deviation. BTC has also been adapted to video compression. Another variation of BTC is Absolute Moment Block Truncation Coding. AMBTC is computationally simpler than BTC. In this paper, we proposed new image compression method based on BTC, which is applied patterns to improve compression rate and image quality. This method make two codebooks to extract 36 and 64 patterns from the highest frequency patterns in BTC. When you are compressing an image, you compare many block patterns to that of codebook and use to compress indexes of identical patterns. We experiment our proposed scheme with 36 patterns and the experimental results showed the compression rate of 1.37 bpp. In this paper, our proposed scheme showed higher compression rate rather than that of BTC. In experiment, we used standard images for the performance evaluation.

• Restorative Dentistry and Endodontics
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• v.26 no.6
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• pp.499-506
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• 2001

불완전하게 충전되거나 충전이 되지않은 isthmus는 다근치에 있어서 근관치료의 높은 실패율을 나타낸다 따라서 본 연구의 목적은 isthmus를 갖는 근관을 골라 근관계의 기구조작을 시행하고 여러 가지 근관충전 방법을 이용하여 근관을 충전한 다음 근단부 형성시 적절한 파일의 크기와 치근단부의 밀폐효과를 각 부위별로 비교평가 해보고자 하는 것이다. Isthmus를 갖는 66개의 발거한 치아를 대상으로 기구조작을 통하여 근관확대를 완성하고 무작위로 각각 20개씩 3군으로 분류한 다음 아래와 같은 방법으로 근관을 충전하였다. : A군 측방가압충전법으로 충전한 군, B군 Continuous wave 충전법으로 충전한 군, C군 MicroSeal$^{TM}$을 이용하여 충전한 군. 나머지 6개의 치아는 3개씩 양성대조군과 음성대조군으로 정하였으며 기구조작 후 근관은 충전하지 않은 채로 두었다. 대조군을 제외한 모든 군은 각각 제조회사의 지시에 따라 근관충전한 후 각 시편의 치근단부 2mm를 제외하고 나머지 부위는 두겹의 nail polish를 발라주었으며 2% methylene blue용액에 침잠시켰다 일주일 후 꺼내어 흐르는 물에 깨끗이 세척한 다음 치근단 부위에서부터 1mm씩 잘라가면서 20배의 배율에서 염색액의 침투정도를 평가하였다. 염색액의 침투정도는 다음과 같이 평가되었다. A군과 B군에서는 많은 수의 시편에서 4mm 이상의 절단면에 염색액의 침투를 보인 반면 C군에서는 단지 3mm절단면에서 총 20개 중 3개의 시편에서 염색액의 침투를 보였을 뿐 그 이상의 절단면에서는 염색액의 침투를 보이지 않았다. 뿐만 아니라 isthmus를 갖는 제2형 근관계의 근단부 형성은 40번 크기보다는 큰 MAF가 요구되는 것으로 나타났다. 이러한 결과를 비추어볼 때 isthmus를 갖는 다근치에서 근관충전시 적어도 40번 이상의 MAF로 근단부 형성을 한 후, 열가소성 Continuous wave 충전법과 MicroSeal$^{TM}$을 이용한 근관충전법이 기존의 측방가압충전법 보다는 효과적인 것으로 나타났다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.747-756
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• 2008

The purpose of this paper is to investigate the effect of the important parameters on the transfer length during the dynamic flame cutting of tendon experimentally. The considered parameters were strand diameter, concrete cover thickness, stirrup, debonding strand and release method. Ten pretensioned concete beam specimens were cast and tested. Time history curves for the axial strain of tendon were measured by electrical resistance strain gauges mounted on the strands. Experimental results indicated that large dynamic shock effects occurred near cut-end during the sudden release. The prestressing forces are dependent on the parameters above considered. The ratio of residual prestressing forces of 12.7 mm strands is greater than 15.2 mm strands. Using debonding strand and gradual release are more efficient for applying prestressing forces.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1722-1725
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• 2003

절연물에 가해지는 열화 중에서 열 사이클(Thermal cycle) 열화를 모사하기 위하여, 대형 터빈 발전기 수냉각 고정자 권선용 바를 대상으로 IEEE Std 1310 규격에 따라 200 사이클의 열 사이클 열화 시험을 수행하였다. 바에 대한 절연 특성을 분석하기 위하여 시험 수행 전후의 Tan ${\delta}$ 및 Tip-up(%, ${\Delta}$ Tan ${\delta}$), 부분방전의 최대 방전량 등을 측정하였고 또한 바를 절단하여 절연물 내의 박리와 도체와 절연물 간의 분리 등을 점검하였다. 최종적으로는 절연파괴 시험을 수행하여 절연파괴 강도를 측정하였다. 시험 결과 초기 절연 특성상의 현저한 변화는 없었으며 양호한 특성을 보였다.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.148-156
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• 2020

The purpose of this study was to compare the success rates of two pulp capping materials, Biodentine™ and RetroMTA^®, used for partial pulpotomy in permanent molars after carious exposures and to compare the final restorative outcome of using composite resin to that of using a stainless steel crown. We studied children who were diagnosed with dental caries of permanent molars and underwent partial pulpotomy. The patients were followed up for more than 1 year. Clinical and radiographic evaluation were used to evaluate the success of each treatment. Fisher's exact test was used to compare the outcomes of two groups. For pulp capping agents, the success rate of using RetroMTA^® was lower than that of using Biodentine™(p < 0.05). Final restoration with composite resin was less successful than restoration with an stainless steel crown(p < 0.05). In combination of pulp capping agents and final restoration material, RetroMTA^®-composite resin shows the lowest success rate(p < 0.05).

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.55-63
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• 2002

Purpose : We investigated the predictive values of relative CBV measured with perfusion MR imaging, and relative CBF measured with SPECT for tissue outcome in acute ischemic stroke. Material and Methods : Thirteen patients, who had acute unilateral middle cerebral artery occlusion, underwent perfusion MR imaging, and $^{99m}Tc-HMPAO$ SPECT within 6 hours after the onset of symptoms. Lesion-to-contralateral ratios of perfusion parameters were measured, and best cut-off values of both parameter ratios with their accuracy to discriminate between regions with and without evolving infarction were calculated. Results : Mean relative CBV ratios in regions with evolving infarction and without evolving infarction were $0.58{\pm}0.27$ and $0.9{\pm}0.17$ (p < 0.001), and mean relative CBF ratios in those regions were $0.41{\pm}0.22$ and $0.71{\pm}0.14$ (p < 0.001). The best cutoff values to discriminate between regions with and without evolving infarction were estimated to be 0.80 for relative CBV ratio and 0.56 for relative CBF ratio. The sensitivity, specificity and efficiency of each cutoff value were 80.6, 87.5, 82.7% for relative CBV ratio, and 72.2, 75.0, 73.0% for relative CBF ratio (p > 0.05 between two parameters). Conclusion Measurement of relative CBV and relative CBE may be useful in predicting tissue outcome in acute ischemic stroke.

• Polymer(Korea)
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• v.33 no.4
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• pp.319-325
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• 2009

The solution polymerization was conducted to synthesize pressure sensitive adhesive for polarizer film using acrylic monomers. 2-Ethylhexylacrylate, butylacrylate, acrylic acid were used as acrylic monomers. The ratio was 2-ethylliexylacrylate:butylacrylate:acrylic acid=25:50:3.6 by reflecting $-40^{\circ}C$ of glass transition temperature in the pressure sensitive adhesive. When 1 wt% of coupling agent was added to the polymerized pressure sensitive adhesive, the light transmissivity was significantly increased. This result is due to the enhancement of adhesive power against liquid crystal cell by Si-O bond of coupling agents. Cross-linking agent was added by 0.5, 1.0, and 1.5 wt% with respect to the synthesized polymer. Initial tackiness decreased, while cohesion increased with increasing crosslinking agent. In the analysis of contact angle, the increase of crosslinking agents yielded the enhancement of surface energy, resulting in the decrease of contact angle. From the measurement of heat resistance, the acrylic pressure sensitive adhesive showed excellent heat resistance regardless of change in temperature and contents in crosslinking agent. In the observation of a cutting plane, the increased crosslinking agent represented a smoother and cleaner section. Comprehensively, the optimum additive amount of crosslinking agent was determined to be 1.0 wt% to monomer.

• Korean Journal of Plant Tissue Culture
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• v.28 no.2
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• pp.103-108
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• 2001

The in vitro plantlets of cassava (Manihot esculenta Crantz cv. MColl 22) could be regenerated from nodal explant cultures in a liquid MS basal medium containing 0.01 mg/L zeatin for 2 weeks. The plantlets of 1.5∼2.5 cm in shoot length were transplanted to a glass bottle containing fine sand and acclimated under non-sterile conditions after excising their intact roots by: 1) prune leaving roots base of 1∼1.5 cm; 2) complete removal of roots; and 3) cutting off the rooting zone. The majority of in vitro-formed intact roots continued growth after transferred to soil, and all of the damaged roots stopped further growth. The plantlets with excised roots began to develop new roots within 7∼10 days after being transferred to a glass bottle, and a few of the pruned roots developed lateral roots from the remaining portion. Pruning and removal of in vitro roots resulted in a high survival rate (>87%), and did not significantly affect ex vitro root regeneration and acclimation, but the plantlets in which the rooting zone had been cut-off showed 73% survival rate. Pruning or removal of in vitro roots before transfer of plantlets is recommended for useful method of commercial micropropagation because of easier handling and high survival rate of plantlets.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.23-30
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• 1996

대략 36,000 base pairs (bp)의 두 가닥짜리 DNA를 지놈으로 가진 사람 아데노바이러스 (Ad)는 DNA 상동성(相同性) 및 생물학적/생화학적 성격이 특이한 49개의 혈청형이 알려져 있는데, 이들 대부분의 Ad가 영유아군 및 면역능이 저하된 성인에서 치사적 결과를 초래할 수 있다. Ad의 세포향성(向性)(tropism)은 매우 다양하여 종류에 따라 상기도 감염, 각결막염, 영유아 장염등을 유발하는데 최근 Ad의 다양한 병원성에 대한 원인을 분자생물학적 수준에서 규명하려는 노력의 일환으로 지역에 따라 주되게 출현하는 Ad형 규명이 활발히 이루어지고 있다. Ad 동정/확인은 표면을 이루고 있는 group 공통항원인 hexon 단백질을 탐지하는 효소면역 측정법 (EIA)에 의하며, Ad형별은 Ad fiber의 세포독성 중화시험에의 한다. 그러나, 세포독성 중화시험이 엄청난 노동력 및 시간을 요구하면서도 민감도/특이도가 만족스럽지 못하여 이를 개선하기 위하여 검체 또는 세포배양에서 Ad DNA를 추출하여 제한효소 절단형태를 비교하는 방법이 개발되었는데 이는 세포배양에 잘 자라지 않는 바이러스주의 형별뿐만 아니라 지역 분리주들의 지놈 변형주를 관찰하는 분자생물학적/분자역학적 연구에도 도움이 되고 있다. 국내에는 Ad와 관련된 소아장염의 빈도가 rotavirus에 의한 것 다음으로 빈번한데도 Ad40/41외에 주되게 출현하는 장내 Ad형들이 전혀 규명된 바 없고, 한국형 Ad들의 지놈형태가 전혀 보고된 바가 없다. 또한 세계적으로 Ad형별 조사지역이 늘어감에 따라 유아장염과 연관된 Ad 역시 Ad40, 41이 외의 형들이 Ad40, 41을 능가하는 것으로 보고되고 있는 지역도 있으나 국내에서는 Ad40, 41이외의 형들은 그 역학적 중요도가 전혀 알려져 있지 않다. 이로서 본 연구의 목적은 Ad주들에 특이 중화항체를 이용한 세포독성 중화시험과 Ad DNA 절단법을 적용하여 한국형 장내 Ad주들의 형별을 처음으로 시도함과 동시에 1989-1991사이 출현한 Ad들의 유전적 변형을 관찰하려는 것이었다. 두 방법 모두 사용하였을 때 주되게 출현하는 장내 Ad형들은 Ad4l, Ad2, Ad7, Ad5, 및 Ad40이었다. Ad40/41-양성 검체를 제외한 Ad hexon-EIA양성들의 77.5%를 형별 할 수 있었던 Ad DNA의 제한효소 절단방법은 형들간의 교차중화로 특이성이 낮았던 중화방법 (47.5%)보다 매우 효율적이어서 두 가지 방법을 함께 적응하였을 때는 40주중의 81.5%인 35주를 형별 할 수 있었다. 또한Ad DNA 제한 효소 절단방법은 Ad7 변이주 (Ad7b)도 탐지 할 수 있었다.