• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권2호
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• pp.155-160
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• 2004

In this paper, we describe the results of a study on the edge enhancement of X-ray images by using their fuzzy system representation. A set of gray scale X-ray images was generated using the EGS4 computer code. An aluminum plate or a lead plate with three parallel strips taken out has been used as the object with the thickness and the width of the plate, and the gap between the two strips varied. We started with a comparative study on a set of the fuzzy sets for their applicability as the input fuzzy sets for the fuzzy system representation of the gray scale images. Then we describe how the fuzzy system is used to sharpen the edges. Our algorithm is based on adding the magnitude of the gradient not to the pixel value of concern but rather to the nearest neighboring pixel in the direction of the gradient. We show that this algorithm is better in maintaining the spatial resolution of the original image after the edge enhancement.

• 한국지역지리학회지
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• 제13권3호
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• pp.254-270
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• 2007

지역혁신체제론은 지역의 혁신적 발전을 유도하여 지역간 경제적 불균형 문제를 해결하는데 유용한 규범적 이론으로 널리 받아들여지고 있다. 그러나 다양한 경험적 연구가 축적되고 있음에도 불구하고, 지역혁신체제론 자체에 대한 심층적이고 비판적인 연구는 부족한 실정이다. 이 논문은 지역혁신체제론의 형성과 발달과정에서 나타난 특색을 이론과 현실정책의 양방향에서 고찰해 봄으로써 본 이론에 대한 이해의 폭을 넓히고자 한다. 이를 통하여 본 이론이 추구하는 가치의 문제를 탐구하고, 이론과 현실사이에서 나타나는 괴리를 발견하며 이를 비판적으로 고찰하고자 한다.

• 품질경영학회지
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• 제41권2호
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• pp.289-300
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• 2013

Purpose: The results of prior studies investigating main effects between diversity and team performance are neither clear nor consistent. This study seeks to provide more evidence for a direct link between these two. The present study also attempts to close a gap in the literature by examining conflict as a moderator of the relationship between diversity and team performance. Methods: As suggested by Williams and O'Reilly(1998), this study examines the effects of perception levels of three specific types of diversity (social category diversity, value diversity, and informational diversity) and two contextual moderators (task conflict and relationship conflict) on team performance. Results: The results show that perception levels of all three types of diversity are significantly related to team performance in the current sample of 313. Results also indicate that relationship conflict significantly interacted with the perception levels of diversity in relating to team performance. Results for task conflict, however, fails to support the hypothesis. Conclusion: The results suggest that the effects of diversity on team functioning depend on how diversity is perceived by team members, rather than actual diversity seen by team members. Theoretical and practical implications are reviewed, and limitations of the study and suggestions for future research are addressed.

• Progress in Superconductivity
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• 제3권2호
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• pp.140-145
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• 2002

An enhancement of the c-axis differential conductance around the zero-bias voltage near the superconducting transition temperature $T_{c}$ has been observed in $Au/Bi_2$$Sr_2$$CaCu_2$$O_{8+x}$ junctions. We attribute such an enhancement to the Andreev reflection (AR) between the surface Cu-O bilayer with suppressed superconductivity and the next superconducting Cu-O bilayer. The continuous evolution of the differential conductance, from gap like depression to an AR-like peak structure, around the zero-bias voltage points to weakening of the barrier strength of the nonsuperconducting layer between adjacent Cu-O bilayers as temperature approaches $T_{c}$ from below. The peak structure disappeared just below the bulk $T_{c}$ value of underdoped Bi2212 single crystals, whereas it survived up to ~1 K above $T_{c}$ in Junctions prepared on slightly overdosed crystals. According to a recently proposed theoretical consideration, a wider temperature range of the AR a bone $T_{c}$ is expected in the underdoped regime when phase-incoherent preformed pairs emerge in the pseudogap state. Our result is in contradiction to the preformed pair scenario. scenario.o.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.402-403
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• 2014

Damping of multi-span tube with loose supports according to the finite support clearances is investigated through the experimental modal analysis. Loose intermediate support leads to strong nonlinearity in tube dynamics, provides statistical nature, and increases tube damping through impacting and friction at the supports. Fraction of critical damping was estimated by the modal curve fitting to parameter estimation from the measured frequency response functions. Magnitude of random excitation force, which can reproduce the in-situ excitation in operating environment, was maintained as constant value with a fine tolerance during vibration testing. Range of input force was carefully selected to cover from the low magnitude excitation for linearly behaved tube motion to high magnitude of force for nonlinearly-behaved tube motion. Estimated critical damping ratio shows scatters in data and tends to increase as the magnitude of rising force and decrease with upward frequency variation. Larger size of support gap increases multi-span tube damping for high magnitude of excitation.

• 한국정보통신학회논문지
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• 제15권10호
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• pp.2065-2071
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• 2011

본 논문에서는 마이크로스트립 선로 공진기와 입출력 단자의 결합 위치에 따른 공진기의 외적 양호도를 위상 특성을 이용하여 구하는 방법을 제시한다. 마이크로파 필터 설계에서 단자 접속 구조로 많이 이용되는 접합 선로 구조와 결합 선로 구조에 대해 단자의 위치와 선로의 폭과 간격에 따른 결과를 제시한다. 이 방법으로 정확한 $Q_e$ 값을 얻을 수 있었고, 이 결과는 결합공진기 필터 설계에 응용될 수 있다.

• Journal of Magnetics
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• 제13권4호
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• pp.115-119
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• 2008

The authors predicted that $Co_2HfSi$, a $Co_2$-based full Heusler alloy, is being a half-metallic ferromagnet by first-principles calculations using the all electron full-potential linearized augmented plane wave method which adopts the generalized gradient approximation. The integer value of the calculated total magnetic moment of 2.00 ${\mu}_B$ per formula unit and a spin gap of 0.69 eV in spin down state confirmed the half-metallicity of bulk $Co_2HfSi$. For the $Co_2HfSi$(001) surface, we considered two possible surface terminations, namely, Co terminated and HfSi terminated surfaces. It was found that half-metallicity was retained at the HfSi-terminated surface but not at the Co-terminated surface. The magnetic moment of surface Co atoms in the Co-terminated surface was slightly lower than that of Co atoms in deep inner-layers, whereas the magnetic moments of Hf and Si atoms at the HfSi-terminated surface were almost same as those in deep inner-layers.

• International Journal of Human Ecology
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• 제17권2호
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• pp.17-30
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• 2016

This study was conducted to make a policy proposal for Korean grandparent-grandchildren families, analyzing what adversities adolescent grandchildren suffer when living in a grandparent-grandchild family, the types of Korean families and how family resilience appears as family power. In order to conduct this study, 20 consenting adolescents were selected for an interview from grandparent-grandchildren families recommended by the U City Healthy Family Support Center. This study suggests the following conclusions. First, we discussed divorce, death, financial bankruptcy related stress, economic difficulties in the present family, accidents involving family members of a grandparent-grandchild family, grandparents' serious disease, death, family conflicts and family comparisons with friends. Second, in the domain of family resilience, desire to maintain the family appeared as a Korean value. In addition, efforts to bond as an emotional family and grandchildren's attitudes of gratitude to grandparents are also expressed. However, family conversation appears weak due to the generation gap between adolescents and grandparents or complications from family stress. Third, the resilience in the family organization appeared weak since there are relatively insufficient socio-economic resources to support the family. This study makes several suggestions for family policies and shows the necessity to develop policies that reflect the needs of grandchildren and grandparents.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.492-495
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• 1987

In this study, PLZT ceramics were fabricated by freeze-drying and normal sintering method. The compositional rate of specimen was selected 9/65/35 (La/Zr/Ti) which have good optical and dielectric properties, sintering time was varied 1, 10, 30, 40, 50, 55, 60 and 65 hr at $1250^{\circ}C$. After sintering, the optical and dielectric properties were investigated with the grain size. As the result of the experiment, freeze-dried powder appeared particle size less than 1 um. The relative dielectric constant was increased linearly with the sintering time, specimen which sintered for 65 hr had the highest value, 5780. Grain was grown with increasing time, in the case of specimen sintered for 60 hr, the grain size was 8.4 um. Transmittance was increased with the grain size. In the case of 8.4 um grain size, the transmittance was 56 %. Curie temperature was decreased linearly by the surface-layer effect of space-charge, in the case of grain size which were 1.8 um and 8.4 um, appeared at $100^{\circ}C$ and $80^{\circ}C$, respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.98-102
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• 2000

Ferroelectric PZT heterolayered thin films were fabricated by spin coating method on the Pt/Ti/SiO2/Si substrate using PZT(10/90) and PZT(90/10) m7etal alkoxide solutions. All PZT heterolayered films showed a homogeneous grain structures without presence of rosette structure. It can be assumed that the lower PZT layers played a role of nucleation site for the formation of the upper PZT layer. Pb-deficient PZT phase was formed at PZT/Pt interface due to the diffusion of Pb element into a Pt bottom electrode. The relative dielectric constant and the dielectric loss of the PZT-6 film were 567 and 3.6%, respectively. Increasing the number of coatings, remanent polarization and coercive field were decreased and the values of the PZT-6 heterolayered film were $7.18\muC/cm^2$ and 68.5kV/cm, respectively. Leakage current densities were increased with increasing the number of coatings, and the value of the PZT-4 film was about $7\times10-8A/cm^2$ at 0.05MV/cm.