• 전자공학회논문지CI
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• 제42권4호
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• pp.33-42
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• 2005

본 논문에서는 소속 함수와 신경망을 이용한 유전자 발현 정보의 분류 기법을 제안한다. 유전자 발현은 유전자가 mRNA와 생체의 기능을 일으키게 하는 단백질을 만들어내는 과정이다. 유전자 발현에 대한 정보는 유전자의 기능을 밝히고 유전자간의 상관 관계를 알아내는데 중요한 역할을 한다. 이러한 유전자 발현 연구를 위한 정보를 대량으로 신속하게 얻을 수 있는 도구가 DNA 칩이다. DNA 칩으로 얻은 수백$\~$수천개의 데이터는 그 데이터만으로는 의미를 갖지 못한다. 따라서 유전자 발현정도에 따라 수치적으로 획득된 데이터에서 의미적인 특성을 찾아내기 위해서는 클러스터링 방법이 필요하다. 본 논문에서는 수많은 유전자 데이터 중에서 주요 정보를 포함한 것으로 판단되는 유전자 데이터를 피셔 기준에 의하여 선택한다. 이때 선택된 데이터들이 클러스터링에 효과적인 데이터라고 보장할 수 없으므로, 클러스터링 성능을 저해하는 유전자 데이터의 영향력을 감소시키기 위해서 소속 함수를 이용하여 특징값을 계산하고, 계산된 특징값으로 얻은 특징 벡터들을 적용하여 역전파 신경망 학습을 수행한다. 본 논문에서 제안한 유전자 발현 정보의 분류 결과로 얻은 클러스터링의 성능은 기존의 연구 결과와 비교했을 때 다양한 유전자 데이터에 대하여 향상된 인식율을 보이는 것을 확인할 수 있었다.

• Journal of Korea Trade
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• 제25권2호
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• pp.95-110
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• 2021

Purpose - This paper intends to conduct theoretical analysis and empirical test on the action mechanism of South Korea-China trade and South Korea's FDI to China on green total factor productivity, so as to provide a new perspective and ideas for the improvement of China's green total factor productivity and promote the high-quality development of China's economy Design/methodology - This paper uses the data of 30 provinces, autonomous regions and municipalities in China from 2004 to 2017 as the research sample, adopts the GML index method of SBM Directional Distance Function to measure GTFP, and analyzes the influence of South Korea-China trade and FDI from South Korea on China's GTFP. Findings - Trade is conducive to promoting technological progress, which has a significant promotion effect on China's green total factor productivity. While FDI has a significant inhibitory effect on China's green total factor productivity, which verifies the "pollution haven" hypothesis. In addition, such influence has certain regional overall heterogeneity. Trade has a more significant promoting effect on GTFP in eastern coastal areas, while FDI has a more significant inhibitory effect on GTFP in central and western inland areas. The interaction between trade and FDI is conducive to the improvement of green total factor productivity, indicating that the benign mechanism of trade and FDI has been formed. Urbanization, industrial structure, human resource level and investment in science and technology are all conducive to the improvement of GTFP. Originality/value - Through theoretical analysis and empirical test on the action mechanism of South Korea-China trade and South Korea's FDI on green total factor productivity, this paper provides a solid theoretical foundation for the further development of China-South Korea economic and trade cooperation in the future.

• 사회복지연구
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• 제44권2호
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• pp.327-358
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• 2013

본 연구는 노년기 인지기능과 일상생활기능장애 변화양상을 분석하고, 이에 대한 인구사회학적 요인의 영향력을 검증하는 것을 목적으로 하였다. 특히 인지손상정도에 따라 변화양상과 인구사회학적 요인의 영향력이 다를 것이라는 가정 하에, 정상인지를 가진 지역사회 거주노인에서 이후 6년여의 추적조사 기간 동안 치매가 발생한 집단(치매발생집단)과 정상인지를 유지하고 있는 집단(정상유지집단)에 따른 차이를 분석하는 것에 초점을 두었다. 분석 자료는 경기도 연천지역에 거주하는 65세 이상 노인 966명을 대상으로 3년여 간격으로 3회 추적 조사된 역학조사 자료를 사용하였다. 자료 분석은 구조방정식모형을 활용한 잠재성장모형(Latent growth model)과 다중집단분석(Multi-group analysis)을 실시하였으며, 통계프로그램은 AMOS 18.0을 사용하였다. 연구 결과, 치매발생집단은 치매로 진단되기 수년 전부터 정상유지집단에 비해 인지기능이 유의하게 낮을 뿐 아니라 이후 인지저하가 약 3.5배가량 빠르게 진행되었다. 일상생활기능장애 궤적의 경우 초기에는 집단 간 유의한 차이가 없다가, 이후 치매발생집단의 일상생활기능장애가 정상유지집단에 비해 약 3배가량 더 급속히 악화되는 것으로 나타났다. 인지기능과 일상생활기능장애에 대한 인구사회학적 요인의 영향력을 살펴본 결과, 인지저하는 여성에서 더 급격한 반면, 일상생활기능저하는 남성에서 더 현저하게 나타났으며, 생애초기에 결정되는 학력이 생애후기의 인지기능에 강력한 영향력을 갖는 것으로 나타났다. 이러한 연구결과에 근거하여 노년기 인지기능과 일상생활기능장애에 대한 개입에서 주목해야 할 고위험군과 그에 대한 실천적 함의를 논의하였다.

• Geomechanics and Engineering
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• 제21권5호
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• pp.423-432
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• 2020

Hydraulic conductivity is one of the engineering properties of soil. This study focusses on the influence of cement content on the hydraulic conductivity of cemented sand, which is investigated based on the results from numerical analysis and laboratory testing. For numerical analysis the cemented samples were scanned using X-ray Computed Tomography (CT) while laboratory testing was carried out using a triaxial setup. Numerical analysis enables us to simulate flow through the sample and provides insight to the microstructure. It quantifies the pore volume, proportion of interconnected voids and pore size distribution in both cemented and uncemented samples, which could be computed only through empirical equations in case of laboratory testing. With reduction in global voids, the interconnecting voids within the samples also reduce with cement content. Gamma cumulative distribution function is used to predict the percentage of voids lesser than a given pore volume. Finally, the results obtained from both numerical analysis and laboratory testing are compared.

• Journal of Power Electronics
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• 제8권1호
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• pp.10-22
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• 2008

The wind-driven doubly fed induction generator (DFIG) is currently under pressure to be more grid-compatible. The main concern is the fault ride-through (FRT) requirement to keep the generator connected to the grid during faults. In response to this, the paper introduces a novel model and new control scheme for the DFIG. The model provides a means of direct stator power control and considers the stator transients. On the basis of the derived model, a robust linear quadratic (LQ) controller is synthesized. The control law has proportional and integral actions and takes account of one sample delay in the input owing to the microprocessor's execution time. Further, the influence of the grid voltage imperfection is mitigated using frequency shaped cost functional method. Compensation of the rotor current pulsations is proposed to improve the FRT capability as well as the generator performance under grid voltage unbalance. As a consequence, the control system can achieve i) fast direct power control without instability risk, ii) alleviation of the problems associated with the DFIG operation under unbalanced grid voltage, and iii) high probability of successful grid FRT. The effectiveness of the proposed solution is confirmed through simulation studies on 2MW DFIG.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.137-140
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• 1993

Electrical properties and thermal annealing effects of $C_{22}$-quinolium(TCNQ) Langmuir-Blodgett(LB) films were studied. Typical current-voltage(I-V) characteristics along the perpendicular direction chow an anomalous behavior of breakdown near the electric-field strength of $10^{6}$V/cm. To see the thermal influence of the specimen, current was measured as a function of temperature(20∼$180^{\circ}C$). It shows that the current increases about 4 orders of magnitude near 60∼$70^{\circ}C$ and remains constant far a while up to ∼$150^{\circ}C$ and then suddenly drops. Such increase of current near 60∼$70^{\circ}C$ seems tn be related to a softness of alkyl chains. Besides the electrical measurements, UV/visible absorption(300∼800 nm) of the thermally annealed sample was measured to see the internal-structure change. It is found that there are four characteristic peaks. At 494 nm, the optical absorption of the thermally annealed specimen at $60^{\circ}C$ starts increase and stays almost constant upto∼ $140^{\circ}C$. And eventually it disappears above $180^{\circ}C$. After heat treatment of the specimen up to $150^{\circ}C$, Uv/visible absorption was measured while cooling.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1573-1576
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• 2003

The quality of bundles is closely related with the apparent thickness. Especially the variation of apparent thickness of bundle determines the qualify of the plane structure made or the bundle such as surface evenness, pore size, and the shape of air-gap, etc.,. This study is dealing with the development of a new measuring system of the thickness of bundle or cross-section by determining the size of the shadow of the object covered by a laser slit beam. Also the measured signal is characterized in terms of the correlogram, the irregularity in wavelength. The correlogram for the irregularity of several sample types could be represented by a sinusoidal function with exponentially decaying amplitude. Moreover, influence of the measuring speed on the signal and the characteristic differences according to the different types of bundle are investigated.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.33-40
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• 2020

The main aim of the study is to test a house pricing model by combining hedonic and asset-based pricing models. An understanding of the relationship between house pricing and its return (the rental income) helps to establish houses as a significant asset class. The model tested the relationship between house pricing (dependent variable) and the house attributes (independent variables) derived from Freeman's framework of housing attributes. This study uses a large data-set of 1,899 sample of new, high-end houses purchased between 2016 and 2019 collected from the national capital region of India (Delhi-NCR). The algorithm was built in R-Script, and stepwise multiple linear regression was used to analyze the model. The analysis of the model proves that the three significant variables, namely, carpet area, pay-off, and annual maintenance charges explain the price function. Further, the model is statistically fit. The major contribution of the study is to understand the key factors and their influence on the house pricing. The model will be helpful in risk assessment in the housing investment and enhance the chances of investment. Policy-makers can use information about the underlying valuation drivers of the house prices to stabilize the market and also in framing the tax policies.

• 패션비즈니스
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• 제18권5호
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• pp.82-98
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• 2014

The influence from the increased income and aging society has amplified the interest in the well-being trend and health. People tend to enjoy sports and outdoor life. The development of smart clothing containing heating function to help maintain body temperature has been actively researched after the mid 2000s. However, the domestic study on heating clothing is severely limited. Practical study on designing heating clothing which can be commercialized is needed. The purpose of this study is to develop a commercialized detachable heating vest design through collaboration with a heating vest manufacturer. The results of this study are as follows: 1) Conducted the interview with manufacturer and a demand survey with consumers in order to develop the heating vest design. 2) Developed heating vest design that reflected the wants in the demand survey and sketched the prototype of detachable heating vest. 3) Made a sample of the heating vest and tested the wearability to illustrate the result of this study. Overall, the wearing test result showed high satisfaction for both gender.

• Macromolecular Research
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• 제16권6호
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• pp.561-566
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• 2008

NR composites with different curing systems were aged thermally at 60, 70, 80, and $90^{\circ}C$ for 2-185 days in a convection oven, and the changes in the crosslink density were investigated as a function of the accelerated thermal aging. The overall crosslink densities increased with increasing aging time irrespective of the aging temperatures and curing systems. The changes in crosslink density were enhanced by increasing the aging temperature. The degree of the increased crosslink density was in the following order: "the conventional cure system > the semi-EV system > the EV system". For short term thermal aging, the change in crosslink density with the aging time was complicated, particularly for low temperature aging. The activation energies of the change in crosslink density with thermal aging using the conventional and semi-EV cure systems increased and then remained relatively constant with increasing aging time, whereas that of the specimen with an EV cure system tended to increase linearly. The experimental results were explained by the dissociation of the existing polysulfidic linkages and the formation of new cross links through the crosslinking-related chemicals remaining in the sample.