• 한국산학기술학회논문지
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• 제15권7호
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• pp.4554-4561
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• 2014

최근에 기존의 컴퓨터 시스템에서 결함허용 분산 어플리케이션을 설계하는데 필요한 요소를 몇 개의 중요한 패러다임으로 구분하여 단순화 되어 왔다. 리더 선택 프로토콜은 그 중에서도 가장 눈에 띄고 비중 있는 프로토콜로 알려져 있다. 선택 프로토콜은 그룹통신이나, 데이터의 원자적인(atomic) 커밋(commit), 복제 데이터의 관리와 같은 프로토콜 코디네이터가 필요한 분야에서 기초적인 설계 초석으로 유용하게 이용 될 수 있기 때문이다. 그러나 이러한 유성성에도 불구하고 기지국 기반 무선 통신 환경에서 아직까지 리더 선택의 문제를 다룬 연구는 많지 않았다. 본 논문에서는 기지국 기반 무선 통신 환경에서 리더 선택 프로토콜을 위한 선택 알고리즘을 제시하고 설계하고자 한다. 또한 설계된 선택 알고리즘은 다른 알고리즘에 비해 결함허용 측면에서 매우 효율적임을 보인다.

• Journal of Ecology and Environment
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• 제41권3호
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• pp.99-106
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• 2017

Background: Plants over-expressing Arabidopsis ABF3 (abscisic acid-responsive element-binding factor 3) have enhanced tolerance to various environmental stresses, especially drought. Using terminal restriction fragment length polymorphism (T-RFLP) analysis, we compared the rhizosphere-associated structures of microbial communities for transgenic potato containing this gene and conventional "Jopoong" plants. Results: During a 2-year field experiment, fungal richness, evenness, and diversity varied by year, increasing in 2010 when a moderate water deficit occurred. By contrast, the bacterial richness decreased in 2010 while evenness and diversity were similar in both years. No significant difference was observed in any indices for either sampling time or plant line. Although the composition of the microbial communities (defined as T-RF profiles) changed according to year and sampling time, differences were not significant between the transgenic and control plants. Conclusions: The results in this study suggest that the insertion of ABF3 into potato has no detectable (by current T-RFLP technique) effects on rhizosphere communities, and that any possible influences, if any, can be masked by seasonal or yearly variations.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 제4회 압출 및 인발가공 심포지엄
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• pp.99-106
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• 2001

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die Insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.

• 대한기계학회논문집A
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• 제20권6호
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• pp.1743-1752
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• 1996

In this paper, a precision inspection technique using CAD/CAI integration is proposed for the parts having very thin and sharp 3 dimensional curve features. The technique begings with feature reconstruction of turbine blades which have 3 dimensional combined feometry, such as splines, and thin circles. The alifnment procedures consistsb of two phases-rough and fine phases : rough phase alignment is based on the conventional 6 point5s probing on the clear cut surfacef, and fine phase alignment is based on the intial measurement on the 3 dimensional curved parts using an lterative measurement feed-back least sequares technique for alignment. Forf the analysis of profile tolerance of parts, the actual measured points are obtained by finding the closet points on the CAD geometry by the developed subdivision technique and the Tschebycheff norm is applied based on iterative fashion, giving accurate profile tolerance value. The developed inspection technique is applied to practical procedures of blade manufacturing and demonstrated high performance.

• BMB Reports
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• 제41권3호
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• pp.204-209
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• 2008

The cDNAs encoding glutathione peroxidase (GPx) were cloned and sequenced from the liver of three Chinese carps with different tolerance to hepatotoxic microcystins, phyto-planktivorous silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis), and herbivorous grass carp (Ctenopharyngodon idellus). Using genome walker method, a 750 bp 5'-flanking region of the silver carp GPx gene was obtained, and several potential regulatory elements were identified in the promoter region of the GPx gene. The silver carp GPx gene was widely expressed in all tissues examined. Despite phylogenetic analysis, assigning this newly described carp GPx to the group of mammalian GPx2, the carp GPx seems more similar to GPx1 from a physiological point of view. The constitutive expression pattern of the three carp liver GPx gene, shows a positive relationship with their tolerance to microcystins.

• 한국생활과학회지
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• 제23권1호
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• pp.47-61
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• 2014

The purpose of this study was to identify the relationship among financial debt burden, psychological factors and financial stress. Data was collected by surveying 450 individuals who were over twenty years old, and 384 were used for the analysis. As the result, first, number of sources of debt, use of each debt, marital status/double income, housing, debt amount and financial stress were found to be significantly different among three groups(debt free, non risky, risky). In addition, marital status/double income, gender, housing and income were found to significantly influence to the probability of being one of the three groups. Second, level of debt burden, age, employment and income were found to significantly influence to financial stress, while psychological factors such as risk tolerance and self-control were not. It might be noteworthy that people in debt were likely to have higher level of stress, while the older, employed, and having higher income were likely to have lower level of stress. This study would provide useful information in terms of debt policy to relieve the financial stress.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.852-858
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• 2007

This paper investigates the dynamic characteristics of a tilted HDD spindle system with fluid dynamic bearings (FDBs). Tilting motion of a HDD spindle system may be caused by improper manufacturing tolerance, such as imperfect cylindricity between shaft and sleeve of FDBs, imperfect perpendicularity between shaft and thrust as well as the gyroscopic moment of the unbalanced mass of the rotating part. Tilting motion may result in the instability of the HDD spindle system and it may increase the disk run-out to limit memory capacity. This research proposes a modified Reynolds equation for the coupled journal and thrust FDBs to include the variable film thickness due to the cylindricity and the perpendicularity. Finite element method is used to solve the Reynolds equation for the pressure distribution. Reaction forces and friction torque are obtained by integrating the pressure and shear stress, respectively. The dynamic behavior is determined by solving the equations of a motion of a HDD spindle system in six degrees of freedom with the Runge-Kutta method to study whirling and tilting motions. This research shows that the cylindricity and the perpendicularity increase the tilting angle and whirl radius of the rotor.

• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1660-1669
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• 2015

The present study describes the gene cloning, overexpression and characterization of a novel nitrilase from hyperthermophilic bacterium Thermotoga maritima MSB8. The nitrilase gene consisted of 804 base pairs, encoding a protein of 268 amino acid residues with a molecular mass of 30.07 kDa after SDS-PAGE analysis. The optimal temperature and pH of the purified enzyme were 45℃ and 7.5, respectively. The enzyme demonstrated good temperature tolerance, with 40% residual activity after 60 min of heat treatment at 75℃. The kinetic constants V_max and K_m of this nitrilase toward 3-cyanopyridine were 3.12 μmol/min/mg and 7.63 mM, respectively. Furthermore, this novel nitrilase exhibited a broad spectrum toward the hydrolysis of the aliphatic nitriles among the tested substrates, and particularly was specific to aliphatic dinitriles like succinonitrile, which was distinguished from most nitrilases ever reported. The catalytic efficiency k_cat/K_m was 0.44 /mM/s toward succinonitrile. This distinct characteristic might enable this nitrilase to be a potential candidate for industrial applications for biosynthesis of carboxylic acid.

• Journal of Astronomy and Space Sciences
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• 제17권1호
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• pp.67-76
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• 2000

2002년에 발사 예정인 과학 위성 1호의 주 탑재체로 원자외선 분광기가 실릴 예정이다. 원자외선 분광기는 영상과 함께 분광의 기능을 함께 수행을 하게 되는데, 이를 위해 광학적인 요소로서 포물 원통 반사경, 슬릿, 타원형 회절 반사경, 그리고 MCP가 사용된다. 천문학적 관측 목표의 달성을 위한 각 광학 요소의 생산 오차와 위치 오차의 허용 한계를 구하였으며, 이 과정에서 도식적 단순화를 통해 민감도표를 해석하여 각 광학 요소의 조작 범위와 정밀도 등을 구하였다. 선형 오차의 경우 $15{\mu}m$, 각 오차의 경우 2' 이내의 정밀도로 광학적 요구 조건을 만족할 수 있을 것이다.

• Journal of Welding and Joining
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• 제22권6호
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• pp.19-24
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• 2004

The laser welding and its analysis of thin-sheet carbon steels were carried out with high power $CO_{2}$ laser. The main factor of weld quality of laser welding is gap and edge quality. This work was preformed to focus on the gap tolerance problem during laser welding. First, bead on plate welding of thin sheet was examined to investigate the effect of laser welding variables, and to obtain optimum welding condition. Butt welding was also carried out to show the effect of gap on the laser weldability of thin sheet. In order to investigate the effect of gap on formability of welded thin sheet, LDH test was caried out. At high welding speed, the partial penetration was obtained by low heat input. Otherwise, porosity was formed in the bead at low weld speed because of too much heat input. The optimum welding condition of welding was derived from bead width, penetration and hardness property. The maximum gap tolerance on laser welding was observed to be about 0.2mm. This gap size has good relationship with beam size of laser spot(about 0.3mm). The formability of welded sheet was about $80{\%}$ value of base metal and the gap size has not affected on the formability, although weld quality is dependent on the gap size.