• 무역학회지
• /
• 제41권5호
• /
• pp.353-371
• /
• 2016

본 연구는 1980-2013년 기간 동안 한국 제조업 내 수출산업과 수입산업의 구조변화와 총요소 생산성의 변화를 분석하고 있다. 분석결과는 제조업 내 13개 산업 중 절반 이상의 산업이 수출입의 방향이 바뀌는 등 전반적으로 산업구조의 변화가 상당히 큰 폭으로 진행되어 왔음을 보여준다. 또 수입산업보다 수출산업에서 수출만이 아니라 생산도 크게 증가하였다. 이는 수출산업이 한국경제의 성장을 주도해 왔음을 보여준다. 또 어느 산업에서나 노동투입보다는 자본투입 증가율이 더 높은데, 이는 그간 생산방법이 보다 자본집약적인 형태로 변해 왔음을 말해준다. 마지막으로 총요소생산성 증가율도 수입산업보다는 수출산업에서 훨씬 더 높다. 패널회귀분석 결과도 수출산업에서 총요소생산성이 더 높음을 말해준다.

• Journal of Microbiology and Biotechnology
• /
• 제10권3호
• /
• pp.287-292
• /
• 2000

Recombinant Aspergillus niger was constructed to express and secrete a biologically active murine granulaocyte macrophage-colony stimulating factor (mGM-CSF). A 500 bp fragment encoding the signal peptide and terminator of glyceraldehyde-3-phosphate dehydrogenase (gpd). The hygromycin phosphotrasferase gene (hph) was used as a selection marker for the fungal transformants. An expression vector was introduced into A. niger ATCC 9642, and a Northern blot analysis indicated the presence of a considerable amount of transcripts from the introduced mGM-CSF. The biological activity of recombinant mGM-CSF (rmGM-CSF) isolated from the culture filtrate was confirmend by measuring the proliferationof the GM-CSF dependent FDC-P1 cell line. It appeared that rmGM-CSF was amenable to the proteolytic activity produced by A. niger, since biological actibity was only observed when the transformants were grown in a protease-repressing medium, and the activity of rmGM-CSF dramatically decreased with an increase of age of the culture. The yield of rmGM-CSF, as determined by ELISA. was 640 ng/l of culture filtrate. Accordingly, its specific activity is estimated to be approximately two-and-a-half times higher than that of a commercial preparation from E. coli.

• 한국전기전자재료학회논문지
• /
• 제30권9호
• /
• pp.551-557
• /
• 2017

It is extremely important to improve methodologies for the lifetime assessment of porcelain insulators. While there has been a considerable amount of work regarding the phenomena of lifetime distributions, most of the studies assume that aging distributions follow the Weibull distribution. However, the true underlying distribution is unknown, giving rise to unrealistic inferences, such as parameter estimations. In this article, we review several distributions that are commonly used in reliability and survival analysis, such as the exponential, Weibull, log-normal, and gamma distributions. Some properties, including the characteristics of failure rates of these distributions, are presented. We use a Bayesian approach for model selection and parameter estimation procedures. A well-known measure, called the Bayes factor, is used to find the most plausible model among several contending models. The posterior mean can be used as a parameter estimate for unknown parameters, once a model with the highest posterior probability is selected. Extensive simulation studies are performed to demonstrate our methodologies.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2001년도 추계학술대회 논문집
• /
• pp.282-286
• /
• 2001

In this study, CT specimens were prepared from spring steel(SUP9) processed shot peening which was room temperature, low temperature and high temperature experiment. And we got the following characteristics from fatigue crack growth test carried out in the environment of room, low temperature and high temperature at $25^{\circ}C$,$-30^{\circ}C$,$-50^{\circ}C$,$-70^{\circ}C$ and $-100^{\circ}C$ in the range of stress ratio of 0.05 by means of opening mode displacement. The threshold stress intensity factor range $\Delta K_{th}$ in the early stage of fatigue crack growth (Region I ) and stress intensity factor range $\Delta K$ in the stable of fatigue crack growth (Region II) was decreased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature and high temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권1호
• /
• pp.7-15
• /
• 2015

We have investigated electrical properties of graphene/Ge Schottky barrier diode (SBD) fabricated on Ge film epitaxially grown on Si substrate. When decreasing temperature, barrier height decreased and ideality factor increased, implying their strong temperature dependency. From the conventional Richardson plot, Richardson constant was much less than the theoretical value for n-type Ge. Assuming Gaussian distribution of Schottky barrier height with mean Schottky barrier height and standard deviation, Richardson constant extracted from the modified Richardson plot was comparable to the theoretical value for n-type Ge. Thus, the abnormal temperature dependent Schottky behavior of graphene/Ge SBD could be associated with a considerable deviation from the ideal thermionic emission caused by Schottky barrier inhomogeneities.

• 한국환경과학회지
• /
• 제13권3호
• /
• pp.233-244
• /
• 2004

This study was conducted to evaluate water quality in the Mankyung River using multivariate analysis. The analysis data which was surveyed from January 1996 to December 2002 in Mankyung river was aquired by the ministry of environment. Twelve water quality parameters were determined on each survey. The results were summarized as follow; Water quality in the Mankyung River could be explained up to 74.90% by four factors which were included in loading of organic matter and nutrients by the tributaries(43.28%), seasonal variation(10.40%), loading of pathogenic bacteria by domestic sewage of Gapcheon (12.41%) and internal metabolism in river(8.81%). The result of cluster analysis by station was classified into three group that has different water quality characteristics. Especially, Iksan river was appeared to considerable water quality characteristics against other station. In monthly cluster analysis, three group was classified by seasonal characteristics. Also, in yearly cluster analysis, three group was classified. It is necessary to control the pollutant loadings by domestic sewage and livestock waste for water quality management of Mankyung river.

• 한국정보통신학회논문지
• /
• 제14권7호
• /
• pp.1729-1736
• /
• 2010

비상업용 정부선박은 국가가 소유 운영하는 선박으로 군함과 마찬가지로 타국 재판관할권으로부터 면제된다. 이는 전통 국제법상의 주권면제이론에 따른 것으로, 국제법상 국가 행위나 재산은 타국의 재판권으로부터 면제되기 때문이다. 주권면제는 판례나 국가관행을 통해 확립된 일반 국제법상의 원칙이다. 문제는 우리 관할수역에서의 타국 비상업용 정부선박에 대한 관할권 제한은 해양안보적 측면에서 상당한 불안요인이 된다는 점이다. 왜냐하면 불순한 의도로 우리 관할수역에 들어와도 주권면제가 인정되기 때문에 그 대응에는 한계가 있을 수밖에 없다. 국제법이나 국제관례를 벗어난 관할권 집행은 국제사회의 비난은 물론 국가책임을 발생시키기 때문에 관련 국제규범의 정확한 이해 및 적용을 통한 합법적 권한행사가 중요하다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권6호
• /
• pp.1228-1236
• /
• 2001

In this study, CT specimens were prepared from ASTH A5l6 steel which was used for pressure vessel plates for moderate and lower temperature service. And we got the fellowing characteristics from fatigue crack growth test carried out in the environment of room and low temperature at $25^{\circ}C$ , $-30^{\circ}C$, $-60^{\circ}C$, $-80^{\circ}C$, $-100^{\circ}C$ and $-120^{\circ}C$ and in the range of stress ratio of 0.1, 0.3 by means of opening mode displacement. At the constant stress ratio, the Threshold stress intensity factor range ΔAKth in the early stage of fatigue crack growth (Region I) and stress intensity factor range $\DeltaK$ in the stable of fatigue crack growth (Region II) was increased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region. The straight line slope relation of logarithm da/dN-$\Delta$K in Region II that is, the fatigue clack growth exponent m increased with descending temperature at the constant stress ratio. It assumed that the fatigue crack growth rate da/dN is rapid in proportion to descend temperature in Region II and the cryogenic-brittleness greatly affect a material with decreasing temperature.

• Structural Engineering and Mechanics
• /
• 제63권1호
• /
• pp.77-88
• /
• 2017

Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.

• Nuclear Engineering and Technology
• /
• 제52권3호
• /
• pp.461-468
• /
• 2020

The improvements of the DeCART/MUSAD code system for uncertainty analysis of HTGR neutronic parameters are presented in this paper. The function for quantifying an uncertainty of critical-spectrumweighted few group cross section was implemented using the generalized adjoint B₁ equation solver. Though the changes between the infinite and critical spectra cause a considerable difference in the contribution by the graphite scattering cross section, it does not significantly affect the total uncertainty. To reduce the number of iterations of the generalized adjoint transport equation solver, the generalized adjoint B₁ solution was used as the initial value for it and the number of iterations decreased to 50%. To reflect the implicit uncertainty, the correction factor was derived with the resonance integral. Moreover, an additional correction factor for the double heterogeneity was derived with the effective cross section of the DH region and it reduces the difference from the complete uncertainty. The code system was examined with the MHTGR-350 Ex.II-2 3D core benchmark. The k_eff uncertainty for Ex.II-2a with only the fresh fuel block was similar to that of the block and the uncertainty for Ex.II-2b with the fresh fuel and the burnt fuel blocks was smaller than that of the fresh fuel block.