• Journal of Oral Medicine and Pain
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• 제23권1호
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• pp.85-99
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• 1998

In order to estimate the tooth-age by degree of attrition, the author has studied 605 stone models from 1996 to 1997. All of the attrition were classified and analyzed by 8 degrees. The result were as follows : 1. The degree of attrition in male was higher than that in female for same age group and especially, canine and first premolar showed the most prominent difference in sex. 2. The most severe attrition in posterior teeth was first molar followed by second molar, first premolar and second premolar in decreasing order of sequence. 3. The coefficient of correlation and relation equations by the degree of attrition were obtained.

• Journal of applied mathematics & informatics
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• 제36권3_4호
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• pp.307-315
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• 2018

Let G be a simple connected graph with n vertices and m edges, with a sequence of vertex degrees $d_1{\geq}d_2{\geq}{\cdots}{\geq}d_n$ > 0. A vertex-degree topological index, referred to as harmonic index, is defined as $H={\sum{_{i{\sim}j}}{\frac{2}{d_i+d_j}}$, where i ~ j denotes the adjacency of vertices i and j. Lower and upper bounds of the index H are obtained.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.686-691
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• 2010

Flash boiling takes place when the thermodynamic state of the liquid deviates from its saturation limit over which the liquid temperature exceeds by a certain degree of superheat. The liquid jet introduced into the lower pressure zone than the liquid saturation pressure experiences a sequence of the atomization and disintegrated into numerous faster and smaller droplets. In the present study spray characteristics for a flash swirl spray were experimentally investigated. Injectant temperature is raised by a high frequency dielectric heating method and local spray characteristics are instantly measured by Global Sizing Velocimetry (GSV, TSI Inc.). Dependence of dimensionless superheat degree and injection pressure on total and local SMDs and mean droplet size is quantitatively examined. The flash swirl spray has the relation in the injection pressure and nozzle diameter in order to determine the spray quality, including the dimensionless superheat degree. Small droplets occur in the void core and local droplet size distributions largely depend on the dimensionless superheat degree and the injection pressure.

• Journal of Life Science
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• 제10권1호
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• pp.32-36
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• 2000

Solitary long terminal repeats(LTRs) of human endogenous retrovirus K family(HERV-K) have been found to be coexpressed with sequences of closely located genes. It has been suggested that HERV-K LTR-like elements entered the primate genome approximately 33-40 million years ago. WE investigated the presence of HERV-K LTR elements in New World monkeys using PCR amplification. Six LTR elements of HERV-K family were identified from New World monkeys, represented by the squirrel and night monkeys. They showed a high degree of sequence homology(96-99%) with the human-specific HERV-K LTR elements. Phylogenetic analysis reveals that an LTR element (SM-1) from the squirrel monkey and another LTR element (NM-1) from the night monkey are very closely related to the human-specific HERV-K LTR elements with low degree of divergence. This finding suggests that some of LTR elements of HERV-K family have recently been proliferated in New World monkeys. A sequence in chromosome Xq26(AL034407) \ulcorner contains an HERV-K LTR element was shown to be present in the human genome, but is absent in the bonobo, chimpanzee, gorilla, orangutan, and gibbon. It has more than 99% homology to other human-specific HERV-K LTR elements. This sequence thus represents and isolated insertion of an evolving class of elements that may have made a particular contribution to human genomic plasticity.

• 대한치과교정학회지
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• 제46권1호
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• pp.3-12
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• 2016

Objective: The purpose of this study was to compare the precision of three-dimensional (3D) images acquired using iTero$^{(R)}$(Align Technology Inc., San Jose, CA, USA) and Trios$^{(R)}$(3Shape Dental Systems, Copenhagen, Denmark) digital intraoral scanners, and to evaluate the effects of the severity of tooth irregularities and scanning sequence on precision. Methods: Dental arch models were fabricated with differing degrees of tooth irregularity and divided into 2 groups based on scanning sequence. To assess their precision, images were superimposed and an optimized superimposition algorithm was employed to measure any 3D deviation. The t-test, paired t-test, and one-way ANOVA were performed (p < 0.05) for statistical analysis. Results: The iTero$^{(R)}$ and Trios$^{(R)}$ systems showed no statistically significant difference in precision among models with differing degrees of tooth irregularity. However, there were statistically significant differences in the precision of the 2 scanners when the starting points of scanning were different. The iTero$^{(R)}$ scanner (mean deviation, $29.84{\pm}12.08{\mu}m$) proved to be less precise than the Trios$^{(R)}$ scanner ($22.17{\pm}4.47{\mu}m$). Conclusions: The precision of 3D images differed according to the degree of tooth irregularity, scanning sequence, and scanner type. However, from a clinical standpoint, both scanners were highly accurate regardless of the degree of tooth irregularity.

• 한국안전학회지
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• 제27권6호
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• pp.192-204
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• 2012

For a severe accident of nuclear power plant, an approach to estimation of the radiological source term using a severe accident code(MELCOR) has been proposed. Although the MELCOR code has a capability to estimate the radiological source term, it has been hardly utilized for the radiological consequence analysis mainly due to a lack of understanding on the relevant function employed in MELCOR and severe accident phenomena. In order to estimate the severe accident source term to be linked with the radiological consequence analysis, this study proposes 4-step procedure: (1) selection of plant condition leading to a severe accident(i.e., accident sequence), (2) analysis of the relevant severe accident code, (3) investigation of the code analysis results and post-processing, and (4) generation of radiological source term information for the consequence analysis. The feasibility study of the present approach to an early containment failure sequence caused by a fast station blackout(SBO) of a reference plant (OPR-1000), showed that while the MELCOR code has an integrated capability for severe accident and source term analysis, it has a large degree of uncertainty in quantifying the radiological source term. Key insights obtained from the present study were: (1) key parameters employed in a typical code for the consequence analysis(i.e., MACCS) could be generated by MELCOR code; (2) the MELOCR code simulation for an assessment of the selected accident sequence has a large degree of uncertainty in determining the accident scenario and severe accident phenomena; and (3) the generation of source term information for the consequence analysis relies on an expert opinion in both areas of severe accident analysis and consequence analysis. Nevertheless, the MELCOR code had a great advantage in estimating the radiological source term such as reflection of the current state of art in the area of severe accident and radiological source term.

• 한국전자통신학회논문지
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• 제7권2호
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• pp.263-269
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• 2012

CDMA는 여러 사용자가 시간과 주파수를 공유하면서 각 사용자에게 확산코드라고 하는 서로 다른 의사잡음수열(pseudonoise sequence)을 할당한다. 각 사용자는 할당된 확산코드를 이용하여 송신할 신호를 변조한다. 신호를 변조하는데 사용하는 코드를 선택하는 것은 CDMA 시스템의 수행능력을 결정하는 데 있어 매우 중요하다. 왜냐하면 품질이 좋은 수열은 사용자들 사이의 신호들의 간섭을 줄이고 신호를 잘 복호할 수 있도록 하기 때문이다. 수신자는 데이터를 복호하기 위해 수신된 부호를 동기화한다. 서로 독립인 코드를 사용하는 것은 동시 다중접속을 가능하게 한다. 본 논문에서는 확산 스펙트럼 통신에서 다중접속 충돌을 최소화하고, 시스템의 보안을 증가시키고 사용자의 수를 늘이는데 도움을 주는 비선형 수열을 생성하고 상호상관관계를 분석한다.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.214-221
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• 1998

A Brevibacterium ammoniagenes gene coding for glucose/mannose-specific enzyme II ($EII^{Glc}$) of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) was cloned by complementing an Escherichia coli mutation affecting a ptsG gene, and the complete DNA nucleotide sequence was determined. The cloned gene was identified to be a ptsG, which enables the E. coli transportment to use glucose more efficiently than mannose as the sole carbon source in an M9 minimal medium. The ptsG gene of B. ammoniagenes consists of an open reading frame of 1,983 nucleotides putatively encoding a polypeptide of 661 amino acid residues and a TAA stop codon. The deduced amino acid sequence of the B. ammoniagenes $EII^{Glc}$ shows, at $46\%$, the highest degree of sequence similarity with the Corynebacterium glutamicum EII specific for both glucose and mannose. In addition, the $EII^{Glc}$ shares approximately $30\%$ sequence similarities with sucrose-specific and ${\beta}$-glucoside-specific EIIs of the several bacteria belonging to the glucose-PTS class. The 161-amino-acid C-terminal sequence of $EII^{Glc}$ is also similar to that of E. coli enzyme $IIA^{Glc}$, specific for glucose ($EIIA^{Glc}$). The B. ammoniagenes $EII^{Glc}$ consists of three domains; a hydrophobic region (EIIC) and two hydrophilic regions (EIIA, EIIB). The arrangement of structural domains, IIBCA, of the $EII^{Glc}$ is identical to those of EIIs specific for sucrose or ${\beta}$-glucoside. While the domain IIA was removed from the B. ammoniagenes $EII^{Glc}$ the remaining domains IIBC were found to restore the glucose and mannose-utilizing capacity of E. coli mutant lacking $EII^{Glc}$ activity with $EIIA^{Glc}$ of the E. coli mutant. $EII^{Glc}$ contains a histidine residue and a cysteine residue which are putative phosphorylation sites for the protein.

• 한국정보과학회논문지:데이타베이스
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• 제32권6호
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• pp.628-640
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• 2005

많은 웹 응용 영역에 XML이 적용되면서 트랜잭션의 변경과 접근에 대한 고립성을 만족시키는 XML 문서에 대한 병행수행은 중요한 이슈가 되고 있다. DTD(혹은 XML 스키마)의 규칙을 잘 지키는 문서를 유효한 XML 문서라 하는데, 유효한 XML 문서에 대한 갱신 연산은 연산 후의 XML 문서가 원래 DTD의 규칙을 그대로 유지해야하는 유효성 문제를 앉고 있다. 일반적인 유효성 검증 방법은 갱신 후의 XML 문서 전체에 대해 유효성을 검증하는 방법이다. 그러나, 위에서 언급한 유효성 검증 방법은 낮은 병행수행의 결과를 낳는다. 따라서, XML 문서의 유효성 검증 범위를 최소화하면서 높은 병행수행 정도를 보이는 새로운 유형성 검증 방법과 로킹 방법이 요구된다. 본 논문은 유효성 검증의 검증 범위를 최소화 시켜 유효성 검증이 효율적으로 수행될 수 있는 시퀀스 그룹 검증 기법을 제안한다. 또한 이 검증 기법의 정확성을 보장하면서 로킹되는 데이타 아이템의 수를 최소화 할 수 있는 경계 로킹 기법을 제안한다. 마지막으로 제안된 유효성 검증 기법과 경계 로킹 기법이 기존의 방법에 비해 트랜잭션의 병행수행 성능을 향상시키고 있음을 실험을 통해 보인다.

• Journal of Welding and Joining
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• 제28권4호
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• pp.33-40
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• 2010

The purpose of this study is to establish a predictive equation of transverse residual stress at the thick FCA butt weldment of large container vessel. The variables used were restraint degree, yield strength of base material, thickness of weldment and welding heat input. Restraint degree at the thick weldment of container ship having the various welding sequence was calculated using FEA. From the result, the H-type specimen was designed to reproduce the level of restraint degree at the actual weldment of containership. Based on the results, the predictive equations of the mean value and the distribution of transverse residual stress at each location of the weldment were established using dimensional analysis and multiple-regression method. The predictive equations were verified by comparing with those measured by XRD in the actual weldment of the ship.