• ETRI Journal
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• v.22 no.3
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• pp.19-26
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• 2000

We describe a detailed numerical scheme to calculate electron transport in quantum wires using the Green function formalism combined with tight-binding orbital basis. As an example of the application, we study the electron transport in a Si nanowire containing a finite potential barrier. The effects of nonzero bias, temperature, and disorder on the barrier-induced oscillatory conductance are investigated within the context of coherent transport model. The oscillatory behavior of the conductance as a function of the Fermi energy is found to be highly sensitive to sample disorder and limited to a very low temperature and a small bias range.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.437-443
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• 1988

We calculate the distribution of the current on the strip by the incident waves on the infinite conducting strip line. The boundary equations represented as the spatial domain function become very complicated equations including convolution integral. Transformed it to the spectral domain, we have a very simple equation is composed by some algebraic multiplication of the current density function and Green's function. the acceleration of iteration procedure is achieved by Kastner's method. The result of iteration gives us the optimum value when it satisfies the iteration stop condition presented in this paper. We confirmed that the induced current density distribution on the stripline has been changed as variaties of the width.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.21-36
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• 2023

As a solution to environmental issues, such as climate change response, the carbon neutrality strategy, urban heat islands, fine dust, and biodiversity enhancement, the value of urban green spaces and trees are becoming important, and various studies dealing with the effects of trees for environmental improvement are being conducted. This study comprehensively considers the preceding studies on planting tree species, planting structure, planting density, and planting base to propose a direction for the planting renewal of green areas in urban parks and applies the findings to a renewal plan to improve the urban environment through landscaping trees. A field survey was conducted on the planting status of Seoul Children's Grand Park, a large-scale neighborhood park in Seoul, and based on the survey data, a planting function evaluation was conducted, and areas needing improvement in planting function were identified. The planting function evaluation was carried out considering the park function setting, planting concept according to spatial function, and planting status. As a result of the study, the direction of planting renewal according to functional change was derived for each stage of planting function evaluation. Increasing the green area ratio is a priority in setting up park functions, but user convenience should also be considered. As a concept of planting, visual landscape planting involves planting species with beautiful tree shapes, high carbon absorption, and fine dust reduction effects. Ecological landscape planting should create a multi-layered planting site on a slope. Buffer planting should be created as multi-layered forests to improve carbon absorption and fine dust reduction effects. Green planting should consist of broad-leaved trees and herbaceous layers and aim for the natural planting of herbaceous species. For plant species, species with high urban environment improvement effects, local native species, and wild bird preferred species should be selected. As for the planting structure, landscape planting sites and green planting sites should be composed of trees, shrubs, and trees and herbaceous layers that emphasize ecology or require multi-layered buffer functions. A higher standard is applied based on the planting interval for planting density. Installing a rainwater recycling facility and using soil loam for the planting base improves performance. The results of this study are meaningful in that they can be applied to derive areas needing functional improvement by performing planting function evaluation when planning planting renewal of aging urban parks and can suggest renewal directions that reflect the paradigm of functional change of created green areas.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.334-341
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• 2001

The provision of QoS control is a key of the successful deployment of multimedia networks. Buffer management plays an important role in QoS control. Therefore, this paper proposes a novel QoS buffer management algorithm named GREEN (Global Random Early Estimation for Nipping), which extends the concepts of ERD (early random drop) and RED (random early detection). Specifically, GREEN enhances the concept of "Random" to "Global Random" by globally considering the random probability function. It also enhances the concept of "Early" to "Early Esti mation" by early estimating the network status. For performance evaluation, except compared with RED, extensive simulation cases are performed to probe the characteristics of GREEN.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.313-316
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• 2007

The purpose of this paper is the development of measurement algorithm for green-sheet based on the digital image processing technique. The Low Temperature Co-fired Ceramic(LTCC) technology can be employed to produce multilayer circuits with the help of single tapes, which are used to apply conductive, dielectric and/or resistive pastes on. These single green-sheets must be laminated together and fired at the same time. Main function of the green-sheet film measurement algorithm is to measure the position and size of the punching hole in each single layer. The line scan camera coupled with motorized X-Y stage is used. In order to measure the entire film area using several scanning steps, an overlapping method is used.

• Structural Engineering and Mechanics
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• v.78 no.2
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• pp.145-161
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• 2021

Dynamic compaction of Aluminum powder using gas detonation forming technique was investigated. The experiments were carried out on four different conditions of total pre-detonation pressure. The effects of the initial powder mass and grain particle size on the green density and strength of compacted specimens were investigated. The relationships between the mentioned powder design parameters and the final features of specimens were characterized using Response Surface Methodology (RSM). Artificial Neural Network (ANN) models using the Group Method of Data Handling (GMDH) algorithm were also developed to predict the green density and green strength of compacted specimens. Furthermore, the desirability function was employed for multi-objective optimization purposes. The obtained optimal solutions were verified with three new experiments and ANN models. The obtained experimental results corresponding to the best optimal setting with the desirability of 1 are 2714 kg·m-3 and 21.5 MPa for the green density and green strength, respectively, which are very close to the predicted values.

• Biomedical Science Letters
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• v.28 no.1
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• pp.50-57
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• 2022

In this study, we tried to examine the possibility of developing a dental product such as tooth decay prevention and oral hygiene by manufacturing a natural polymer film for oral use. Natural polymer films were prepared from shark byproduct extract (SBE) and gellan gum (GG). As an antibacterial substance, the antibacterial activity of green tea extract against tooth decay-causing bacteria was measured. An film was prepared by adding green tea extract to the composition of SBE and GG. The mechanical, solubility, moisture content and antibacterial function of the prepared film were investigated in detail. Also, the incorporation of GTE into the SBE/GG film improved the physical performance of the film. Increasing the content of GTE improved the antioxidant and antibacterial properties of the film. Formulation of antimicrobial SBE/GG film containing green tea extract was established and these results evidently showed potential for cavity prevention products application.

• Advances in concrete construction
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• v.1 no.4
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• pp.319-340
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• 2013

This paper presents a comparative study on the double-K fracture parameters of concrete obtained using four existing analytical methods such as Gauss-Chebyshev integral method, simplified Green's function method, weight function method and simplified equivalent cohesive force method. Two specimen geometries: three point bend test and compact tension specimen for sizes 100-500 mm at initial notch length to depth ratios 0.25 and 0.4 are used for the comparative study. The required input parameters for determining the double-K fracture parameters are derived from the developed fictitious crack model. It is found that the cohesive toughness and initial cracking toughness determined using weight function method and simplified equivalent cohesive force method agree well with those obtained using Gauss-Chebyshev integral method whereas these fracture parameters determined using simplified Green's function method deviates more than by 11% and 20% respectively as compared with those obtained using Gauss-Chebyshev integral method. It is also shown that all the fracture parameters related with double-K model are size dependent.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.81-87
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• 2004

The objective of our research was an international comparison focusing on studies conducted on parks and green spaces undertaken in Japan and Korea. We also aim to clarify the similarities and differences between the two countries and consider the key features of the researches on the field of landscape architecture. We compared the recent trends of Japanese institute with Korean observed in the theme of research papers adopt title of them. The research period spanned approximately twenty years, from 1980 to 2003. We employed the Table of Contents information search system to research academic journal articles and to select the journals that included articles with the key words [park(s)] or [green space(s)] in their title. We chronologically arranged the journals for each country, based on the total number of journals and classification categories. We then conducted a comparative examination among the two countries. We also contributed information on the circumstances behind the formulation or amendment of some policies and laws and we checked the results against the research trend. Among the selected journals, the number of papers was the highest by the Institute of Landscape Architecture. But the reason for increase of the number of papers on green spaces in Japanese journals was not published by the Institute of Landscape Architecture but by the City Planning Institute and the Architecture Institute. In Japan, the papers on parks categorized under historical study were the highest among all categories. On the other hand, in Korean journals, papers on parks categorized under historical study were few. A similar trend was recognized in papers on green spaces. Every society is concerned with the study of function and effect. However, some exact differences have been observed by category classification. In Japan, the percentage of function and effect papers on parks was less than those on green spaces. In Korea, both percentages for these groups were high. The category of system and policy accounted for $17\%$ of the papers on green spaces in Korea. This result was higher than the number of papers on green spaces and parks in Japan and parks in Korea. Recently, the number of papers focusing on large-scale green space system has decreased in Japan. The trend in the study of parks and green spaces on a regional scale or at an individual level will be closely monitored. Systems and modeling studies have been focusing in Korea. The understanding between the administration and the citizens was peculiar to each country.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.3
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• pp.442-447
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• 1998

Visible photoluminescence (PL) has been observed generally in the blue and green spectral region from anodically etched porous Ge as well as spark processed Ge. Porous Ge which is prepared by anodic etching without UV light illumination displays the PL peak max of 52 nm (2.38 eV), while porous Ge with UV light illumination exhibits PL peak blue shift to a 470 nm (2.63 eV). Spark processed Ge shows a PL peak max of 520 nm with shoulder peaks at 420 nm and 610nm. The values of energy shift as a function of decreasing temperature between 300 K and 20 K is 0.53 and $1.89\;meVK^{-1}$ for anodic etched Ge without UV illumination and with UV illumination, respectively. On the contrary, no continuous blue shift of PL peak as a function of decreasing temperature is observed for the green luminescing spark processed Ge. From the results of PL as a function of temperature the origin of blue and green luminescing anodically etched Ge as well as spark processed Ge is discussed.