• The Journal of Engineering Research
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• v.5 no.1
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• pp.73-87
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• 2004

The synthesis and crystallization of amorphous calcium carbonate($CaCO_3$.$nH_2 O$) obtained from gas-liquid reaction between aqueous solution of calcium hydroxide and carbon dioxide at 15~$50^{\circ}C$ are investigated by electrical conductometry, XRD and TEM. The results are as follows: The initial reaction products prior to the formation of precipitated calcium carbonate is amorphous calcium carbonate. The electrical conductivity values in the slurry are decreased during the formation of amorphous calcium carbonate which covers particle surface of calcium hydroxide and retard the dissolution of calcium hydroxide into the solution. that amorphous calcium carbonate is unstable in the aqueous solution and crystallizes finally to calcite by the through-solution reaction. While amorphous calcium carbonate crystallizes into chain-like calcite, the conductivity values are recovered rapidly and the apparent viscosity of slurry containing higher concentration of calcium hydroxide increase. At below pH 9.5, chain-like calcite separates into individual particles to form precipitated calcium carbonate. The formation and synthetic temperature range of amorphous calcium carbonate is most suitable a primary decreasing step(a-step) at $15^{\circ}C$ in the electrical conductometry.

• Journal of Oral Medicine and Pain
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• v.26 no.1
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• pp.87-93
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• 2001

SOX9과 SRY 유전자는 척추동물에서 남성고환의 형성을 유도하는 요소로 알려졌다. SOX9 유전자는 SRY related HMG box gene중 하나로 유전질환의 XY성전환 및 성을 결정하는 데에 관여하며 성결정시기에 그 양에 따른 성전환 발생등 연구가 진행되고 있다. 그러나 이 유전자가 성별판정에 유용할 지는 확실치 않다. 반면 SRY 유전자는 포유동물에서의 배형성시기 고환형성을 결정하는 Y염색체 유전자로 남성에만 존재하고 여성에는 존재 않는다. 현재까지 이을 이용하여 법의학적 검체에서 남성판별에 유용하게 사용되고 있다. 본 실험에서는 X, Y와 같은 성염색체가 아닌 상동염색체상에 있으면서 SRY 유전자와 더불어 남성고환을 결정하는 또다른 요소로서의 기능을 가진 SOX9 유전자를 치아에서 검출하여 법의학적 성별판정에 유용할 수 있는지 알아보고자 본 연구를 수행하였다. 남녀각각 5개의 치아에서 치수와 상아질을 분리한 후 DNA를 추출하여 SOX9과 SRY 유전자의 특이적인 시발체를 제작하고 중합효소연쇄반응을 시행하여 증폭하고 전기영동을 시행하였다. 그 결과 SOX9 유전자는 남녀모두에서 유전자가 검출되었고, SOX9 유전자산물과 SRY 유전자를 혼합하여 사용시 남자에서만 유전자가 검출되었다. 이는 법의치과학적 성별판정에 있어 SOX9 유전자는 사람의 치아에서는 남녀 모두 존재하며 남녀 구별을 위한 성별판정에는 이용할 수 없으며 SRY 유전자와 함께 적용시 남성 특이적 SRY 유전자 검사중 발생할 수 있는 가성 음성 반응여부를 확인하는 데 유용할 것으로 사료된다.

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.47-53
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• 2000

Brown과 Proschan의 수리모형과 이를 일반화한 Lee와 Seoh의 시스템 수리모형이 고려된다. Brown과 Proschan의 수리모형은 시스템의 고장시 완전수리가 확률 p로, 불완전수리가 확률 1-p로 이루어지는 모형이고, Lee와 Seoh의 수리모형은 시스템 고장시 완전수리와 불완전수리의 선택이 마르코프 연쇄과정에 따라 결정되는 모형이다. 본 논문에서는, 완전수리비용과 불완전수리비용을 고려한 후, 시스템의 수명분포가 지수분포, 균일분포, Weibull분포인 경우로 나누어, 위 두 시스템 수리모형에서의 최적화가 연구된다.

• Journal of Korea Water Resources Association
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• v.35 no.5
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• pp.583-595
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• 2002

The purposes of this study are to perform the management and monitoring of droughts for Mokpo area via the monthly Palmer index(PDSI), the data is obtained from the Mokpo meteorological station, and the used data are in the period of 1906 to 1999. Monthly Palmer index is classified into 7 stochastic classes and its dynamic change of monthly transition probability estimated by Markov chain is investigated. We also estimate the steady state probability of the classified PDSI. The 4th class shows the highest frequency of 49.6% out of 7 classes and the 7th class which is the most extreme drought show that a stochastic transition probability is more or less larger than an empirical one. Also, we found that the monthly steady state probability could be used for the forecasting of changing pattern of drought magnitude for the study area.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.3
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• pp.13-22
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• 2014

This article investigates the effects of prior firm founding experience, prior firm's performance, same industry matters, entrepreneurship communities or educations on subsequent firm performance. This study also explores whether same industry matters and entrepreneurship communities or educations have interaction effects between entrepreneurial experience and subsequent firm performance. The results show that prior firm founding experience and prior firm's performance have a positive effect on subsequent firm performance. The rest of variables have no significant direct effects on firm performance. However, same industry matters and entrepreneurship communities or educations have interaction effects of entrepreneurial experience on firm performance. Based on results of this empirical study, this study draws some implications that entrepreneurs can become serial entrepreneurs and experience entrepreneurial success.

• Journal of Genetic Medicine
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• v.5 no.1
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• pp.15-20
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• 2008

Purpose : Large exon deletions in the DMD gene are found in about 60% of DMD/BMD patients. Multiplex PCR has been employed to detect the deletion mutation, which frequently generates noise PCR products due to the presence of multiple primers in a single reaction as well as the stringency of PCR conditions. This often leads to a false-negative or false-positive result. To address this problematic issue, we introduced the dual primer oligonucleotide (DPO) system. DPO contains two separate priming regions joined by a polydeoxyinosine linker that results in high PCR specificity even under suboptimal PCR conditions. Methods : We tested 50 healthy male controls, 50 patients with deletion mutation as deletion-positive patient controls, and 20 patients with no deletions as deletion-negative patient controls using DPO-multiplex PCR. Both the presence and extent of deletion were verified by simplex PCR spanning the promoter region (PM) and 18 exons including exons 3, 4, 6, 8, 12, 13, 17, 19, 43-48, 50-52, and 60 in all 120 controls. Results : DPO-multiplex PCR showed 100% sensitivity and specificity for the detection a deletion. However, it showed 97.1% sensitivity and 100% specificity for determining the extent of deletions. Conclusion : The DPO-multiplex PCR method is a useful molecular test to detect large deletions of DMD for the diagnosis of patients with DMD/BMD because it is easy to perform, fast, and cost-effective and has excellent sensitivity and specificity.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.171-183
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• 2007

Urban transport demand is derived from activity participation. A variety of individual daily activities based on the decisions on activity participation result in collective spatial behavior. The travel derived from the effort to overcome the spatially distributed locations of adjacent activities represents the detailed structural relationships among activities. An activity-based approach provides an important framework of analyzing contemporary urban daily life in the sense that it studies the interaction between individuals' daily decision making and social practice in time and space, on the one hand, and socio-spatial environment on the other. The current study identifies representative patterns of urban daily activity implementations and analyzes the correlation between representative patterns and individuals' characteristics and contextual characteristics. The study shows that urban daily activity patterns can be grouped in a limited number of representative patterns, which are systematically correlated with socio-spatial characteristics. The results provide related transportation policy implications.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.203-211
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• 2023

A Markov chain Monte Carlo (MCMC) simulation is proposed for probabilistic full waveform inversion (FWI) in a layered half-space. Dynamic responses on the half-space surface are estimated using the thin-layer method when a harmonic vertical force is applied. Subsequently, a posterior probability distribution function and the corresponding objective function are formulated to minimize the difference between estimations and observed data as well as that of model parameters from prior information. Based on the gradient of the objective function, a proposal distribution and an acceptance probability for MCMC samples are proposed. The proposed MCMC simulation is applied to several layered half-space examples. It is demonstrated that the proposed MCMC simulation for probabilistic FWI can estimate probabilistic material properties such as the shear-wave velocities of a layered half-space.

• Journal of Korean Philosophical Society
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• v.126
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• pp.295-320
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• 2013

This thesis amis to demonstrate basically that language has the potential enough to be able to determine human's belief, attitude and behavior for Spinoza. As long as the language could be conceived with the potential to do, then it is very important in human community. And it is through dynamic and changeable, not fixed state, that meaning of this language is revealed. For Spinoza, even sign and its meaning compose one language system, but both of which are different from the other community. Because language as sign used in a specific society is articulated expression of body image, each imagination as idea is necessarily followed by its sign. This fact makes us say that language express imaginal knowledge. But language should not be considered as an means to express adequate idea of it. By the reason that order of meaning is only determined by the connection of signs, and that of meanings, each meaning of sign is not fixed. In this respect, certain meaning is changeable on account of changing new order of ideas. Through re-arranging new order of meaning, language could express more adequate and better idea than before. but what the most important fact is that it is not sufficient to express adequate idea by the means of language. Power of language determining human's belief and attitude does not depend on whether meaning of sign is true or not, but on hegemony of order of meaning. with this regard, this world could be seen as battle area of conflicting for orders of meaning. The more members accept newly created rational thought through newly arranged words, the more new views of value gain power. Solidarity of man using common language can change the world. For this purpose, first step depends on freedom of thought, freedom of deliverance of thought in which spinoza insists through A Theological - Political Treatise.

• The Korean Journal of Financial Management
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• v.14 no.1
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• pp.75-105
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• 1997

최근 수년사이 우리나라 경제의 근간을 이루고 있는 중소기업의 부도사태가 갈수륵 확산되는 양상을 보이고 있다. 이로 인해 귀중한 경제자원이 사장되는가 하면 종업원이 실직을 당하고 부도기업과 거래해온 계열 및 하청업체들도 연쇄부도에 휩싸임으로써 연관산업은 물론 지역경제 및 국가경제에까지 큰 손실을 끼치고 있다. 따라서 어떻게 중소기업의 부도를 예방하고 그 피해를 최소화할 수 있느냐 하는 문제는 초미의 관심사로 대두됐다. 본 연구는 이같은 관점에서 중소기업부실화의 효율적인 예방대책마련에 필수적인 근거자료를 제시하는데 초점을 맞추고 있다. 이를 위해 설문조사를 실시하고 정책의 우선순위결정을 위한 통계적 모형인 AHP(analytical hierarchy process)모형을 이용해 설문조사내용을 분석한바, 부실화원인간의 계층적 구조가 파악되고 원인별 영향도가 계량화되고 있다. 이러한 연구결과는 부실화예방을 위한 정책의 우선순위결정이 가능함을 보여주는 것이다. 또 부실화연구에 새로운 접근방법을 구사한 점도 특기할만하다.