• 한국도서관정보학회지
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• 제45권3호
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• pp.441-462
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• 2014

본 연구는 최근 문헌정보학에 대두되고 있는 정보코먼스 및 러닝코먼스에 대한 개념과 차이점을 분석하고 일본 공공도서관의 러닝코먼스화 사례연구를 통하여 공공도서관의 러닝코먼스화 방향에 관한 시사점을 얻고자 하였다. 러닝코먼스화 분석을 위해 러닝코먼스의 구성요소를 이론적으로 정리해보고, 공공도서관에 적합한 분석의 틀을 설계하고 일본의 공공도서관에 대한 사례분석을 실시하였다. 사례 분석의 결과, 도서관이 정보의 도구에 의해 주도된 정보 코먼스를 넘어 본연의 학습기능으로 돌아가고 있음을 보여주고 있다. 또한 러닝코먼스를 지향하는 공공도서관이 해야 할 미래 과제에 대한 시사점을 던져주고 있다.

• 전력전자학회논문지
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• 제21권3호
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• pp.254-259
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• 2016

Recently, DC distribution systems have become a hot issue because of the increase in digital loads and DC generation systems according to the expansion of renewable energy technologies. To obtain the practical usage of DC electricity, safety should be guaranteed. The main concerns for safety are twofold: one side is human protection against electric shocks, and the other is facility protection from short faults. "Effects of current on human beings and livestock" (IEC 60479) defines a human body impedance model in electric shock conditions that consists of resistive components and capacitive components. Although the human body impedance model properly works in AC electricity, it does not well match with the electric shock behavior in DC electricity. In this study, the contradiction of the human body impedance model defined by IEC 60479 in case of DC electricity is shown through experiments for the human body. From the analysis of experimental results, a novel unified human body impedance model in electric shock conditions is proposed. This model consists of resistive components, capacitive components, and an inductance component. The proposed human impedance model matches well for AC and DC electricity environments in simulation and experiment.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권6호
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• pp.784-791
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• 2004

본 논문에서는 퍼지논리에 기초한 Fisherface 얼굴인식 방법의 확장을 다룬다. Fisherface 얼굴인식 방법은 주성분 분석 기법만을 이용하는 경우에 비해 조명의 방향, 얼굴의 포즈, 감정과 같은 변동에 대해 민감하지 않은 장점을 가지고 있다. 그러나, Fisherface 방법을 포함한 얼굴인식의 다양한 방법들은 입력 벡터가 한 클래스에 할당되어질 때 그 클래스에서 소속의 정도를 0 또는 1로서 나타낸다. 따라서 이러한 방법들은 얼굴영상들이 조명이나 보는 각도로 인해 변형이 생기는 경우에 인식률이 저하되는 문제가 있다. 본 논문에서는 PCA에 의해 변환된 특징벡터에 퍼지 소속도를 할당하는 것으로, 퍼지 소속도는 퍼지 kNN(k-Nearest Neighbor)으로부터 얻어진다. 실험 결과 ORL, Yale 얼굴 데이타베이스에서 기존의 인식방법 보다 향상된 인식 성능을 보임을 알 수 있었다.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2003년도 제2차 연례학술대회 발표논문집
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• pp.133-138
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• 2003

The prediction of protein secondary structure has been an important bioinformatics tool that is an essential component of the template-based protein tertiary structure prediction process. It has been known that the predicted secondary structure information improves both the fold recognition performance and the alignment accuracy. In this paper, we describe several novel ideas that may improve the prediction accuracy. The main idea is motivated by an observation that the protein's structural information, especially when it is combined with the evolutionary information, significantly improves the accuracy of the predicted tertiary structure. From the non-redundant set of protein structures, we derive the 'potential' parameters for the protein secondary structure prediction that contains the structural information of proteins, by following the procedure similar to the way to derive the directional information table of GOR method. Those potential parameters are combined with the frequency matrices obtained by running PSI-BLAST to construct the feature vectors that are used to train the support vector machines (SVM) to build the secondary structure classifiers. Moreover, the problem of huge model file size, which is one of the known shortcomings of SVM, is partially overcome by reducing the size of training data by filtering out the redundancy not only at the protein level but also at the feature vector level. A preliminary result measured by the average three-state prediction accuracy is encouraging.

• 전기학회논문지
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• 제64권6호
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• pp.857-863
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• 2015

OF cable with excellent reliability and economic efficiency, has been used as the main cable of underground transmission in Korea. However, as XLPE cable is excellent in view points such as reduction of loss, convenience on the construction/operation, and manufacturing technology, it has been replaced as instead of OF cable. Also, when the aging occurs in some sections of OF cable, the section is replaced as XLPE cable without changing of whole cable line. However, there are some differences like electrical constants between both types of cables. Therefore if underground transmission system will be operated as combined connection composited of both cables, it should be proved that overvoltage is stable in steady and transient state. This paper describes the effectiveness of connection operation in combined OF and XLPE cable. For the evaluation of effectiveness, some important analysis such as sheath component voltage, lightning and switching overvoltage, single line-to-ground fault are carried out in steady and transient state. EMTP/ATPDraw is used for modeling and analysis of system.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1422-1431
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• 2015

The reliability of power system components can be affected by a numbers of factors such as the health level of components, external environment and operation environment of power systems. These factors also affect the electrical parameters of power system components for example the thermal capacity of a transmission element. The relationship of component reliability and power system is, therefore, a complex nonlinear function related to the above-mentioned factors. Traditional approaches for reliability assessment of power systems do not take the influence of these factors into account. The assessment results could not, therefore, reflect the short-term trend of the system reliability performance considering the influence of the key factors and provide the system dispatchers with enough information to make decent operational decisions. This paper discusses some of these important operational issues from the perspective of power system reliability. The discussions include operational reliability of power systems, reliability influence models for main performance parameters of components, time-varying reliability models of components, and a reliability assessment algorithm for power system operations considering the time-varying characteristic of various parameters. The significance of these discussions and applications of the proposed techniques are illustrated by case study results using the IEEE-RTS.

• 대한기계학회논문집A
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• 제21권11호
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• pp.1885-1895
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• 1997

As track density needs to increase to the order of 10, 000 tpi, the suspension has become a critical component in hard disk drives. One of the main obstacles to attain high track density is the structural resonances of the suspension in lateral direction. We investigate the suspension dynamics through the experimental modal analysis and the finite element method. An LDV (Laser Doppler Vibrometer) is employed to measure the response of the suspension which is excited by a shaker and an inpulse hammer for the free condition and the loaded condition, respectively. After comparing the experimental and numerical results, we study how the initial geometry of the bend region affects the suspension dynamics. It is found that the natural frequency of the sway mode decreases as the bend ratio and the bend angle increase. The shape of torsional mode changes as the mass of a slider increases, resulting in a local decrease in the natural frequency.

• 한국정밀공학회지
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• 제19권8호
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• pp.63-70
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• 2002

In end milling process, the undeformed chip section area and cutting forces vary periodically with phase change of the tool. However the real undeformed chip section area deviates from the geometrically ideal one owing to cutter runout and tool shape error. In this study, a method of estimating the real undeformed chip section area which reflects cutter runout and tool shape error was presented in up end milling process using measured cutting forces. The average specific cutting resistance, Ka is defined as the main cutting force component divided by the modified chip section area. Ka value becomes smaller as the helix angle increases from $30^circC \;to\;40\circC$. But it becomes larger as the helix angle increases from $40^\circ$to 50 . On one hand, the Ka value shows a tendency to decrease with increase of the modified chip section area and this tendency becomes distinct with smaller helix angle.

• 생약학회지
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• 제32권4호통권127호
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• pp.280-286
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• 2001

Epigallocathechin-3-gallate (EGCG), the main polyphenol component in green tea, inhibits angiogenesis, urokinase, and matalloproteinases, and EGCG also has the antioxidative property. Recent reports proposed that EGCG may modulate the immune response on allergy or asthma. Human nasal mucosal fibroblasts are a rich source of cytokines, inflammatory mediators, and chemokines. Chemokines are important for the recruitment of leukocytes to sites of infection, which is essential in host defense. The objective of this study was to investigate the effect of EGCG on the expression of the chemokines such as RANTES (regulated upon activation, normal T cell expressed and presumably secreted), eotaxin, and interleukin-8 (IL-8) in human nasal mucosal fibroblasts after stimulation with cytokines like IL-4, tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$, and $interferon-{\gamma}\;(IFN-{\gamma})$. To detect the expression of chemokine genes, RT-PCR was performed. Expressions of RANTES, eotaxin, and IL-8 mRNA stimulated with IL-4 and $TNF-{\alpha}$ were increased, respectively, while the expression of those genes incubated with $IFN-{\gamma}$ was similar pattern compared to control group. Analyses of chemokine genes of cells pretreated with EGCG showed that the expressions of eotaxin, and IL-8 genes stimulated $IFN-{\gamma}$ were higher compared with those not pretreated with EGCG.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.439-447
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• 2008

One of the key elements in efforts to minimize noise radiation from a powertrain is the knowledge of the main radiating component and the relation between the surface vibration of a powertrain and the sound pressure. In this research, the powertrain model is developed based on FEM(finite element method). This model is applied to the prediction of the vibration of a powertrain by using ADAMS and the radiation noise by using BEM(boundary element method). According to this numerical analysis, the surface vibration of a powertrain is investigated as a source of radiated noise. This surface vibration is caused by the 1st order natural vibration of the cylinder block and its mode shape is the torsion mode. Therefore, this mode shape is modified to reduce the surface vibration of the powertrain. The radiation noise of the modified powertrain is also reduced to $5{\sim}12\;dB$. This modification is very successful for the noise reduction based on the CAE technology.