• Korean Journal of Radiology
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• 제22권8호
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• pp.1341-1351
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• 2021

Objective: To compare the quality of various polychromatic and monochromatic images with or without using an iterative metal artifact reduction algorithm (iMAR) obtained from a dual-energy computed tomography (CT) to evaluate total knee arthroplasty. Materials and Methods: We included 58 patients (28 male and 30 female; mean age [range], 71.4 [61-83] years) who underwent 74 knee examinations after total knee arthroplasty using dual-energy CT. CT image sets consisted of polychromatic image sets that linearly blended 80 kVp and tin-filtered 140 kVp using weighting factors of 0.4, 0, and -0.3, and monochromatic images at 130, 150, 170, and 190 keV. These image sets were obtained with and without applying iMAR, creating a total of 14 image sets. Two readers qualitatively ranked the image quality (1 [lowest quality] through 14 [highest quality]). Volumes of high- and low-density artifacts and contrast-to-noise ratios (CNRs) between the bone and fat tissue were quantitatively measured in a subset of 25 knees unaffected by metal artifacts. Results: iMAR-applied, polychromatic images using weighting factors of -0.3 and 0.0 (P_-0.3i and P_0.0i, respectively) showed the highest image-quality rank scores (median of 14 for both by one reader and 13 and 14, respectively, by the other reader; p < 0.001). All iMAR-applied image series showed higher rank scores than the iMAR-unapplied ones. The smallest volumes of low-density artifacts were found in P_-0.3i, P_0.0i, and iMAR-applied monochromatic images at 130 keV. The smallest volumes of high-density artifacts were noted in P_-0.3i. The CNRs were best in polychromatic images using a weighting factor of 0.4 with or without iMAR application, followed by polychromatic images using a weighting factor of 0.0 with or without iMAR application. Conclusion: Polychromatic images combined with iMAR application, P_-0.3i and P_0.0i, provided better image qualities and substantial metal artifact reduction compared with other image sets.

• Imaging Science in Dentistry
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• 제41권4호
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• pp.177-181
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• 2011

Pyknodysostosis is a rare autosomal recessive disorder characterized by the post natal onset of short limbs, short stature, and generalized hyperostosis along with acro-osteolysis with sclerosis of the terminal phalanges, a feature that is considered essentially pathognomonic. Other features include persistence of fontanelles, delayed closure of sutures, wormian bones, absence of frontal sinuses, and obtuse mandibular gonial angle with relative mandibular prognathism. We report a case of 17-year-old girl who presented with a chief complaint of retention of deciduous teeth. General physical examination demonstrated short stature, frontal and parietal bossing, depressed nasal bridge, beaked nose, hypoplastic midface, wrinkled skin over the finger tips, and nail abnormalities. Radiographs showed multiple impacted permanent and supernumerary teeth, hypoplastic paranasal sinuses with acro-osteolysis of terminal phalanges, and open fontanelles, and sutures along with wormian bones in the lambdoidal region.

• 대한수학회보
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• 제56권4호
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• pp.939-959
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• 2019

Using generalized graded crossed products, we give necessary and sufficient conditions for a simple algebra over a Henselian valued field (under some hypotheses) to have Kummer subfields. This study generalizes some known works. We also study many properties of generalized graded crossed products and conditions for embedding a graded simple algebra into a matrix algebra of a graded division ring.

• 대한수학회논문집
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• 제37권4호
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• pp.1099-1129
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• 2022

In this paper, we establish Liouville type theorems for the fractional powers of multidimensional Bessel operators extending the results given in [6]. In order to do this, we consider the distributional point of view of fractional Bessel operators studied in [12].

• 한국재료학회지
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• 제11권9호
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• pp.721-726
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• 2001

Directional solidification experiments have been carried out at the solidification rates from 0.5 to 50$\mu\textrm{m}$/s in Mar M-247LC superalloy in which several important liquid properties were estimated by analyzing the interface stability and temperature gradient at the solid/liquid interface. The diffusion coefficient in the liquid was estimated by employing the constitutional supercooling criterion. The temperature gradients changed with solidification rates and latent heat of solidification. The thermal conductivities of solid and liquid could be estimated by heat flux balance at the solid liquid interface.

• 생명과학회지
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• 제9권2호
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• pp.176-181
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• 1999

본 연구는 누에(Bombyx mori)에서 cloning한 BomMAR의 염기서열을 기초로 하여 곤충 MLE(mariner-like ele-ment)의 계통분석을 통한 누에의 분자적 계통 관계를 이해하고자 수행하였다. 전체 10 종의 MLE중에서 15%의 낮은 상동성을 보이는 인간 MLE(Hsmarl)을 제외한 9종의 MLE의 DNA 염기서열을 이용한 UPGMA 분석 결과, BmoMAR을 포함한 10종의 MLE가 세 가지의 subfamily 로 grouping되는 것을 알 수 있었으며, 누에는 genetic distance 0.4332에서 같은 lepidoptera(나비목) 의 H. cecropia, almond moth, webworm 및 microcaddisfly와 함께 grouping 되었다. 따라서 이와 같은 결과는 MLE가 곤충의 계통분석에 유용한 molecular tool이 될 수 있음을 보여준다.

• 정보처리학회논문지A
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• 제13A권1호
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• pp.79-86
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• 2006

최근 인간의 다양성과 SNP과의 연관연구에 드는 비용을 줄이기 위해서, 최소의 tagSNP을 선택하는 문제를 해결하기 위한 연구가 이루어지고 있다. 일반적으로 많은 수의 SNP들을 여러 블록으로 분할하여 각 블록 내에서 tagSNP을 선택하는 접근방법이 사용되고 있다. 본 논문에서 구현된 MarSel은 기존의 블록분할 접근 방법의 문제로 볼 수 있는 생물학적 의미의 부족을 해결하고자, 연관불균형(Linkage Disequilibrium, LD)의 개념을 도입한 시스템이다. 기존의 접근방법에서는 생물학적으로 재조합(recombination)이 일어나지 않는 연속된 구간에서도 여러 블록으로 나누어지는 문제가 생겼던 반면, MarSel에서는 연관불균형 계수 |D'|에 의해서 연속된 구간이 하나의 블록으로 유지된 상태에서 tagSNP을 선택하게 된다. 또한 MarSel에서는 각 블록 내에서 tagSNP을 선택 할 때에 엔트로피(entropy) 기반의 최적해 알고리즘을 이용함으로써 최소한의 tagSNP 선택을 보장하게 되며, 기존의 구현된 시스템들보다 더 많은 양의 데이터를 효율적으로 처리할 수 있도록 구현되었기 때문에 염색체 레벨의 연관 연구도 가능하게 해준다.

• Journal of Plant Biotechnology
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• 제1권1호
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• pp.46-55
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• 1999

The expressed sequence tags(ESTs) from immature seed of rice, Oryza sativa cv Milyang 23, were partially sequenced and analyzed by homology. As of 1998, the partial sequences of about 6,600 cDNA clones were analyzed from normal and normalized immature seed cDNA libraries. About 2,200 ESTs were putatively identified by BLASTX deduced amino acid sequence homology analysis. About 20% of them were putatively identified as storage proteins. Also the clones were highly homologous to genes involved particularly in starch biosynthesis, glycolysis, signal transduction and defenses. Compared to 35% of redundancy in the ESTs of normal cDNA library, that from the substracted library was 15%. The Korea Rice Genome Network is maintained to provide the updated information of sequences, their homologies and sequence alignments of ESTs. For the stable expression of transgene in rice, diverse vectors were developed for overexpression, targeting and gene dosage effect with transit peptides (Tp) and matrix attachment region (MAR) sequence from chicken lysozyme locus. The rice calli were transformed via Agrobacterium tumefaciens LBA4404(pSB1) with the triparental mating technique and selected by herbicide resistance. The green fluorescent protein(GFP) gene in expression vector under the control of rbcS promoter-Tp was overexpressed upto 10 % of the total soluble protein. In addition, the Tp-sGFP fusion protein was properly processed during translocation into chloroplast. The expression of sGFP in the presence of MAR sequences was analyzed with Northern and immunoblot analysis. All the lines in which sGFP transgene with MAR sequence, showed position independent and copy number-dependent expression, while the lines without MAR showed the varied level of expression with the integration site. Thus the MAR sequence significantly reduced the variation in transgene expression between independent transformants.

• 대한방사선기술학회지:방사선기술과학
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• 제43권2호
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• pp.79-85
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• 2020

The influence of metal artifact in CT image depends on the type of metal materialsm, the reconstruction algorithm, and scan parameters. The presence of metal artifacts was quantitatively evaluated by applying the standard and MAR algorithms through the phantom study. In the change of tube voltage applied the standard algorithm, metal artifact decreased to 44.9% for 80 vs 120 kVp, 24% for 100 vs 120 kVp, while the image taken at 140 kVp increased the artifact by 19% compared to 120 kVp. When the tube current was increased from 100 to 300 mA, there was no significant difference in the CT value and noise. Black band and white strike artifacts occurred up to 65.9% in the adjacent ROI of the metal driver, whereas titanium screw produced lesser metal artifact than that of the metal driver. The combination of 120kVp or higher tube voltage-standard algorithm was effective in removing black band artifacts as well as white streak by high density materials. However, MAR reconstruction algorithm was useful in improving image quality under the environment of low kVp and high density materials, without increase of radiation exposure.

• 한국정보통신학회논문지
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• 제6권1호
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• pp.55-61
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• 2002

실시간 인터넷 멀티미디어 서비스들은 고속의 데이터 전송과 QoS, 멀티캐스트를 요구한다. 인터넷의 하부구조인 ATM 망에서 IP 멀티캐스트를 지원하기 위한 방안으로 MARS가 제안되었으며, 또한 최선형 서비스 기반의 인터넷에서 서비스의 품질을 보장하기 위하여 자원예약 신호 프로토콜인 RSVP가 제안되었다. 본 논문에서는 단일 MCS기반의 MARS가 가지는 단점들을 보완하기 위해 2개 이상의 MCS를 가지는 다중 MCS MARS기반의 ATM 망에서 클러스터내의 ATM 호스트가 특정 IP 멀티캐스트 그룹에 가입할 경우MARS가 종단간 전송지연을 최소화하는 MCS를 할당하여 송신자와 수신자간에 최소의 전송지연을 가질 수 있도록 하였다. 그리고 자원을 예약하기 위한 Resv메시지를 MARS가 수신했을 때 자원예약 메시지를 처리할 수 있도록 그 기능이 확장된 MARS는 유지하고 있는 MCS 관리 table을 참조하여 MCS를 재 선정함으로써 MCS가 유지하고 있는 병합된 QoS를 변경시키지 않고 MARS와 MCS의 처리 부하를 줄일 수 있는 방안을 제시하고자 한다.