• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.219-226
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• 2013

Organic semiconductor-based soft electronics has potential advantages for next-generation electronics and displays, which request mobile convenience, flexibility, light-weight, large area, etc. Organic field-effect transistors (OFET) are core elements for soft electronic applications, such as e-paper, e-book, smart card, RFID tag, photovoltaics, portable computer, sensor, memory, etc. An optimal multi-layered structure of organic semiconductor, insulator, and electrodes is required to achieve high-performance OFET. Since most organic semiconductors are self-assembled structures with weak van der Waals forces during film formation, their crystalline structures and orientation are significantly affected by environmental conditions, specifically, substrate properties of surface energy and roughness, changing the corresponding OFET. Organo-compatible insulators and surface treatments can induce the crystal structure and orientation of solution- or vacuum-processable organic semiconductors preferential to the charge-carrier transport in OFET.

• Archives of design research
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• v.17 no.4
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• pp.375-384
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• 2004

The general tendency of approach to Korean Design History has been focusing its primary interest on the grand story in relation to the problems of modernization in political, economical and social aspects of Korea. In the discourse of modernization, however, there are two sides immanent in the modernization: there is the formal, institutional and authoritative modernization developed inside the capitalistic mode of production and the informal, individual and cultural modernization manifested in the mode of everyday lives. Especially, despite the viewpoint of the latter being embossed as an alternative approach in various areas including the academic world of history since the collapse of socialism, the historical recognition of the phenomena of modern design by the Korean design historians is more like the 'history from the above' that exists at the level of the discourse outside the reality rather than the 'history from the below' that exists within the ordinary life. To grant a sense of balance in such frame of historical understanding, it requires the restructuring the design history of Korea through the cultural perspectives from having the representation of mundane lives realized by the voluntary design activity of the common people as research subjects. One of the methods to acquire an answer to such problem is decoding, in the manner of 'cultural history', the life-long domestic artifact made by Madame Yang, Gap Jo (currently 87 years of age) who is a model of typical Korean mother. Through the historical rumination on the traces of unpretentious lives of the people that has been buried under the grand narrative of the Korean Design History, a new era aimed for the historical prospect of Korean design as cultural history will be possible by excavating the petit yet multi-layered meaning of Korean designs.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.77-87
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• 2004

In this paper a back-propagation neural network model is developed to estimate the preconsolidation pressure of Korean soft soils based on 176 oedometer tests and 63 piezocone test results, which were compiled from 11 sites - western and southern parts of Korea. Only 147 data were used for the training of the neural network and 29 data, which were not used during the training phase, were used for the verification of trained network. Empirical and theoretical models were compared with the developed neural network model. A simple 4-4-9-1 multi-layered neural network has been developed. The cone tip resistance $q_T$ penetration pore pressure $u_2$, total overburden pressure $\sigma_{vo}$ and effective overburden pressure $\sigma'_{vo}$ were selected as input variables. The developed neural network model was validated by comparing the prediction results of the proposed neural network model for the new data which were not used for the training of the model with the measured preconsolidation pressures. It can also predict more precise and reliable preconsolidation pressures than the analytical and empirical model. Furthermore, it can be carefully concluded that neural network model can be used as a generalized model for prediction of preconsolidation pressure throughout Korea since developed model shows good performance for the new data which were not used in both training and testing data.

• Korean Journal of Cognitive Science
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• v.7 no.1
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• pp.57-74
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• 1996

This paper presents a comparison of recognition performance of the features used inthe recent handwritten korean character recognition.This research aims at providing the basis for feature selecion in order to improve not only the recognition rate but also the efficiency of recognition system.For the comparison of feature performace,we analyzed the characteristics of theose features and then,classified them into three rypes:global feature(image transformation)type,statistical feature type,and local/ topological feature type.For each type,we selected four or five features which seem more suitable to represent the characteristics of korean alphabet,and performed recongition experiments for the first consonant,horizontal vowel,and vertical vowel of a korean character, respectively.The classifier used in our experiments is a multi-layered perceptron with one hidden layer which is trained with backpropagation algorithm.The training and test data in the experiment are taken from 30sets of PE92. Experimental results show that 1)local/topological features outperform the other two type features in terms of recognition rates 2)mesh and projection features in statical feature type,walsh and DCT features in global feature type,and gradient and concavity features in local/topological feature type outperform the others in each type, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.536-543
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• 2016

The installation of grounding systems is important for the safe operation of power systems, and the soil resistivity is an important design consideration for such systems. It varies markedly with the soil type, moisture content and temperature. The Jeju geological structure is formed in a multi-layered structure characteristic of volcanic areas and, and the geological ground resistance values can appear even constructed the same areas ground system different from the soil structure. In this study, a mock-up system using representative soil from Jeju was constructed to analyze the variation of the grounding resistance. The mock-up system was configured using the Gauss-Newton algorithm inversion method to analyze the model numerically using the Wenner method through the soil resistivity measurements used to create the ground model. Also, we analyzed the change in the general ground resistance characteristics of the copper rod, copper pipe, and carbon rod that are used for grounding. The variation of the grounding resistance with the hydration status was found to be $2.9[{\Omega}]$, $16.5[{\Omega}]$ and $20.1[{\Omega}]$ for the copper rod, copper pipes, and carbon rod, respectively, and the influence of the ground moisture resistance of the carbon rod was found to be the lowest with a value of $141[{\Omega}]$.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.72-72
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• 2012

Lithium rechargeable batteries have been widely used as key power sources for portable devices for the last couple of decades. Their high energy density and power have allowed the proliferation of ever more complex portable devices such as cellular phones, laptops and PDA's. For larger scale applications, such as batteries in plug-in hybrid electric vehicles (PHEV) or power tools, higher standards of the battery, especially in term of the rate (power) capability and energy density, are required. In PHEV, the materials in the rechargeable battery must be able to charge and discharge (power capability) with sufficient speed to take advantage of regenerative braking and give the desirable power to accelerate the car. The driving mileage of the electric car is simply a function of the energy density of the batteries. Since the successful launch of recent Ni-MH (Nickel Metal Hydride)-based HEVs (Hybrid Electric Vehicles) in the market, there has been intense demand for the high power-capable Li battery with higher energy density and reduced cost to make HEV vehicles more efficient and reduce emissions. However, current Li rechargeable battery technology has to improve significantly to meet the requirements for HEV applications not to mention PHEV. In an effort to design and develop an advanced electrode material with high power and energy for Li rechargeable batteries, we approached to this in two different length scales - Atomic and Nano engineering of materials. In the atomic design of electrode materials, we have combined theoretical investigation using ab initio calculations with experimental realization. Based on fundamental understanding on Li diffusion, polaronic conduction, operating potential, electronic structure and atomic bonding nature of electrode materials by theoretical calculations, we could identify and define the problems of existing electrode materials, suggest possible strategy and experimentally improve the electrochemical property. This approach often leads to a design of completely new compounds with new crystal structures. In this seminar, I will talk about two examples of electrode material study under this approach; $LiNi_{0.5}Mn_{0.5}O_2$ based layered materials and olivine based multi-component systems. In the other scale of approach; nano engineering; the morphology of electrode materials are controlled in nano scales to explore new electrochemical properties arising from the limited length scales and nano scale electrode architecture. Power, energy and cycle stability are demonstrated to be sensitively affected by electrode architecture in nano scales. This part of story will be only given summarized in the talk.

• Archives of design research
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• v.14 no.3
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• pp.145-154
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• 2001

These days, the products like Walkman, mobile phone, notebook PC, PDA are moving together with our body, and in the imaginary world like internet, our other self, Avatar is moving in place of our body on the cyber world. These products are related with our human body, and when considering the ones, attached to the human body, and having the meaning of mental combination like these, as the combination of the human and the products, it is necessary to examine these products in approaching them with respect to the combination relation between the human and the products. As a result of examining we can understand that the products, said to combine with the human body, are coming oui steadily. and recently, the inclination on the combination and the movement appears strongly. As this background, there are a breakdown of dichotomy thought, mixed sexual imitation, cyber culture, techno culture. concept of informative nomands, phenomenon which the division of human and machine becomes vague. and the miniaturization of products. imitation of human, phenomenon that the Inclination on the combination with human is more accelerated by networking. These products combine with human body at each wearing type in the various forms. Its functions become multi-layered, and closer to the human body physically. or its communication becomes high·graded and, they have the recombined form through the existing products which the human has And, they communicate each other. have the strong fashionable property, and the characteristics like the imaginary product to imitate the human body and substitute for the human behave.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.2
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• pp.77-84
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• 2012

This study suggested the planting model of Zelkova serrata communities in the areas with the warmth index of both 80~100 and $100{\sim}120^{\circ}C{\cdot}month$. Warmth index was calculated with 449 weather points using inverse distance weighted interpolation method. The planting species were selected by correlation analysis between Z. serrata and each species of four or more frequency among the 36 relev$\acute{e}$ surveyed for this study. The result of this study is summarized as follows : Warmth index of Z. serrata communities was among $74{\sim}118^{\circ}C{\cdot}month$. Results of the correlation analysis between Z. serrata and each species observed that the Z. serrata belongs to the tree layer with warmth index of 80~100 and $100{\sim}120^{\circ}C{\cdot}month$. On the other hand, the species of Carpinus laxiflora, Quercus serrata, Prunus sargentii and Platycarya strobilacea appeared only in the tree layer with warmth index of $80{\sim}100^{\circ}C{\cdot}month$. Z. serrata and Styrax japonica appeared in the subtree layer with the warmth index of 80~100 and $100{\sim}120^{\circ}C{\cdot}month$, while Acer pseudosieboldianum, Lindera erythrocarpa, Acer mono, Quercus serrata, etc. appeared in the subtree layer with the warmth index of $80{\sim}100^{\circ}C{\cdot}month$. Z. serrata, Ligustrum obtusifolium, Lindera obtusiloba, Callicarpa japonica and Zanthoxylum schinifolium all appeared in the shrub layer with the warmth index of 80~100 and $100{\sim}120^{\circ}C{\cdot}month$. Lindera erythrocarpa, Orixa japonica, Staphylea bumalda, Akebia quinata and Sorbus alnifolia appeared in the shrub layer with the warmth index of $80{\sim}100^{\circ}C{\cdot}month$ and Styrax japonica and Stephanandra incisa appeared in the shrub layer with the warmth index of $100{\sim}120^{\circ}C{\cdot}month$, The numbers of each species planted in a $100m^2$ area of the Z. serrata community were suggested as follows : five in tree layer, five in subtree layer and nine in shrub layer. The average area of canopy are suggested to be about $86m^2$ for tree layer, $34m^2$ for subtree layer and $34m^2$ for shrub layer.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.327-331
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• 2020

In that this study is a subject and character of risk, emerging security covers non-military areas in addition to traditional military security: environmental security, human security, resource security, and cyber security. The rise of these risks is not only changing the phenomenon of the new expansion of security areas, but also the expansion of the number and scope of security entities and the aspect of security world politics. These risks are transnational security issues at the global level in terms of their nature and extent of the damage, as well as multi-layered ones that affect local and personal security issues at the regional and national levels. In addition to national actors, non-state actors such as international organizations, multinational corporations, and global civil society, and furthermore, technology and social systems themselves are causing risks. Therefore, to solve the new security problem, it is necessary to establish a middle-level and complex governance mechanism that is sought at the regional and global levels beyond the fragmented dimension of the occurrence of new security issues that have been overlooked in the existing frame of perception, and to predict and find ways to respond to new security paradigms that have been identified in a broader sense.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.328-336
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• 2002

Recently, new light curing unit utilizing the plasma xenon arc lamp is introduced. This curing unit is operated at relatively high intensity, so shortening the curing time significantly. The aim of this experiment was to estimate curing capability of plasma xenon arc lamp curing unit compared to traditional halogen lamp curing unit. Degree of conversion was evaluated by Raman spectroscopy after irradiation of specimens with halogen lamp curing unit(Optilux 150, Demetron, USA) for 20s, 40s, 60s and plasma xenon arc lamp curing unit(flipo, Lokki, France) for 2s, 3s, 6s. The results showed that strong light intensity of plasma xenon arc lamp curing unit did not compensate for short exposure time completely. So, Multi-layered curing within 2mm thickness and additional exposure time is recommanded when light-cured composite resin is polymerized with plasma xenon arc lamp curing unit.