• Macromolecular Research
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• v.15 no.5
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• pp.437-442
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• 2007

Poly(ethylene glycol) methyl ether (PEG)-poly(${\beta}$-amino ester) (PAE) block copolymers were synthesized using a Michael-type step polymerization, and the construction of pH-sensitive polymeric micelles (PM) investigated. The ${\beta}$-amino ester block of the block copolymers functioned as a pH-sensitive moiety as well as a hydrophobic block in relation to the ionization of PAE, while PEG acted as a hydrophilic block, regardless of ionization. The synthesized polymers were characterized using $^1H-NMR$, with their molecular weights measured using gel permeation chromatography. The $pK_b$ values of the pH-sensitive polymers were measured using a titration method. The pH-sensitivity and critical micelle concentration (CMC) of the block copolymers in PBS solution were estimated using fluorescence spectroscopy. The pH dependent micellization behaviors with various bisacrylate esters varied within a narrow pH range. The critical micelle concentration at pH 7.4 decreased from 0.032 to 0.004 mg/mL on increasing the number of methyl group in the bisacrylate from 4 to 10. Also, the particle size of the block copolymer micelles was determined using dynamic light scattering (DLS). The DLS results revealed the micelles had an average size below 100 nm. These pH-sensitive polymeric micelles may be good carriers for the delivery of an anticancer drug.

• Land and Housing Review
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• v.11 no.1
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• pp.109-116
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• 2020

This study aims to establish an approach to assess urban flood vulnerability by identifying social characteristics such as the road transportation and the vulnerable groups. Assessment procedures comprise three steps as: (1) composing the assessment criteria to reflect the urban characteristics; (2) calculating the weight; and (3) evaluating the vulnerability. The criteria were adopted by Delphi survey technique. Four criteria as land cover, residents, vulnerable areas, and disaster response were adopted in the current study. To determine the weight set of criteria, subjective and objective methods were combined. The weight set was determined using the combined method which reflects the Delphi method and Entropy analysis. In the process of data-based construction, GIS tools wwere used to extract administrative unit materials such as land cover, road status, and slope. Data on population and other social criteria were collected through the National Statistical Office and the Seoul Metropolitan statistical data. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) technique, which uses materials from cell units in order to rank the closest distance to the best case and the farthest distance from the worst case by calculating the distances to the area of assessment, was applied to assess. The study area was the Dorimcheon basin, a flood special treatment area of Seoul city. The results from the current study indicates that the established urban flood vulnerability assessment approach is able to predict the inherent vulnerable factors in urban regions and to propose the area of priority control.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.53-65
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• 2012

This study was performed to investigate the currents status of the sexual assaults on women public transportation users and to provide solutions in order to provide safe transportation services to women. Data was collected through in-depth interviews with career women in Gyeonggi-do. The main purpose of the interview was to understand their experiences about sexual assaults while using public transport and to investigate the extent to which their experiences affected their transportation-related behaviors. The effects of various related transport policies on women behaviors were also analyzed by estimating structural equation models. The results showed that among them, CCTV, accessible warning bells, and more police presence seemed to be more effective, but that woman-only sections were not as effective as others in reducing the number of crimes. The results implied that individual subjective norms and their perceived behavioral control, behavior intention were important factors. Based on these results, we recommended additional policies more effective in sexual crime reduction.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.223-234
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• 1998

Recently, the interests of the construction of the permeable submerged breakwaters have been increased to preserve and to improve the coastal environment, and to control the incident waves and littoral transport. It is very important to predict the wave transformation precisely over the permeable submerged breakwaters. This study discusses nonlinear wave transformation and characteristics by using BEM based on the frequency domain method of the 3rd-order Stokes waves. The Dupuit-Forchheimer formula is applied to the analysis of the fluid resistance of rubble stones, and the equation about equivalent linear frictional coefficient is newly modified based on the Lorentz's condition for the equivalent work. The numerical results are compared with the experimental ones for verification. These two results give a close agreement each other. It is confirmed that the present method of the 3rd-order Stokes waves estimates more precisely than that of the 2nd-order Stokes waves.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.475-481
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• 2006

The major problem in closing water like lakes and ponds in Korea is that because they are exposed to surrounding, so easily polluted. The pollution in closing water can be caused by not only artificial factor like sewage but also natural factor like elution from sediment. For insurance of safe and satisfied water source, lots of studies and projects are now going on. In this study, we examined the behavior and effect of microbubble ($3{\sim}10{\mu}m$) produced by device called O.S.D (Oxygen Solubillization Device) in small size pond. The value of oxygen transfer coefficient ($K_La$) was 0.68/min independently of air flow rate, 6.5 times higher than commercial aeration stone and the variation of nitrogen concentration was $0.008NO_3/O_2$, DO concentration was potentially saturated for 24 hr. From the results of pilot plant, SOD of experiment (O.S.D) and control were $12.18gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ and $47.95gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ respectively. In conclusion, because O.S.D has extraordinary physico-chemical characteristics, it can contribute to improvement of both the waterbody and the sediment environment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.202-208
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• 2006

The goal of this study is to develop knowledge representation method for the construction and evaluation of ontology for diagnosis in oriental medicine. To develop the expert system for decision making on diagnosis and treatment, the systematic and structural knowledge which can be processible in EMR(Electronic Medical Record) must be precedent, and the Computational Process which control the system as well. This study set up an ontology as a trial model to represent the oriental medical knowledge into the machine processible one. Protege 2.1 has been used to build the ontology, and the serialization format of our ontology is the XML document based on OWL. The components of oriental medical diagnosis was arranged with the combination of symptoms which belong to the certain symptom patterns. Then natural language which expresses the oriental medical diagnosis components were converted into the logical sentence, and individual characteristic symptoms into each values of specific properties. In addition to the study, the diagnosis software for oriental medicine was developed and it used the ontology which we developed. Sequently, we tested the software to confirm the appropriateness of ontology. The result of the test shows that diagnostic questions are automatically formulated according to the diagnosis components of this ontology and that as such diagnostic results are induced. Therefore, the ontology system in this study will be efficient to develop the diagnosis program and useful as a tool for doctors to make decision. But, it is not recommendable to apply the system to the clinical environment until the clear diagnosis standards are introduced, and the more reliable diagnosis program can be developed based on the more appropriate ontology mentioned above.

• Journal of Internet Computing and Services
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• v.10 no.6
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• pp.159-171
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• 2009

The objective of this research is to explore a method to utilize a programmable robot, as a potential learning tool in the elementary school's curricula. Due to their programmability and operational ease of use, programmable robots are among digital toys that today offer specially instructive features. In this research, we developed the robot game-based project contents as a tool for teaching the elementary school children to learn the algorithm, the essential part of computer programming. The LEGO material, selected as the construction kit for robot, consists of a mechanical assembly system, a set of sensors and actuators, a central control unit, a programming environment. The project requires the children to complete 3 separate tasks, each of which is developed based on the principles of algorithm. The classroom feedback supports that the robotic experiences provided the children with fun and absorption. It is likely that implementing learning with robot in regular classroom in elementary school can bring new possibilities to the educational system, provided that a thorough preparation backs up the plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3240-3250
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• 2014

This study aims to draw a correlation in the choice of automobiles as the preferred mode of personal transport in relation to three factors: 5Ds, urban form and individual-level characteristics. The analysis result shows that the control at the individual level is required to analyze effective urban character and urban form elements to decrease the car choice and the 5Ds demonstrate meaningful relation to decreasing the car choice. However, it may be concluded that the density and the diversity, well-known elements in decreasing the car choice among Western cities do not show relatively large impact on Korean cities.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.21-28
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• 2008

The CFT (Concrete Filled Steel Tube) columns became popular in high rise building construction due to not only its composite effect but also economic advantage. However, it has been pointed out in various previous researches that the current practice in CFT columns may lead the steel tube to probable local buckling at critical sections of the columns right after yielding. To resolve such a problem, the TR-CFT (Transversely Reinforced Concrete Filled Steel Tube) column is proposed to control or at least delay the local buckling state at the critical section by wrapping the CFT columns with carbon fiber sheet. The validity of the proposed column system is validated through the present paper by observing the experimental performance and comparing it with the analytical prediction of the TR-CFT columns with hish strength concrete. It is also shown that the current design code provisions such as ACI-318, in which the contribution of concrete confining effect filled in steel tube is not appropriately accounted for, may contain too much conservatism.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.851-856
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• 2008

Construction of large-scale container ports with the productivity improvements in container cranes shortened time of staying port to increase the level of service it harbors efforts accelerated. About container crane system exerted on the input, which is designed to look good performance considering the states feedback control system. The states observer designed of container cranes state variables that are expected to measurement noise or particular measurement signal. In the status of existing research, the feedback gain matrix and the state observer gain matrix are searched by being separated solving. But the feedback gain matrix and the state observer gain matrix are searched by RCGAs at once that be used robust search method in this paper.