• Polymer(Korea)
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• v.36 no.4
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• pp.542-548
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• 2012

Morphological characteristics and formation of symmetric polystyrene-block-poly(1,4-butadiene) copolymer (PS-b-PBD) in thin films upon solvent-annealing were investigated by using atomic force microscopy (AFM). The thin films solvent-annealed in cyclohexane revealed the perforated lamellae of poly(1,4-butadiene) in the matrix of polystyrene while those solvent-annealed in n-hexane exhibited highly disordered patterns. Interestingly, when the thin films of PS-b-PBD were solvent-annealed with binary mixtures of cyclohexane and n-hexane, the morphological transition from the perforated lameallae to the perpendicularly-oriented lamellae of poly(1,4-butadiene) could be induced by changing the mixing ratio of both solvents. We also demonstrated that after microdomians of poly(1,4-butadiene) were successfully degraded by UV-$O_3$, linear poly(dimethyl siloxane) chains were back-filled into the etched regions of the thin film and then converted to silica nano-objects by oxygen plasma treatments.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.97-101
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• 2011

Interplanetary space between Sun and Earth is area of flowing very fast solar wind which is contained X ray, flare, corona mass, etc. occurred Sun surface to Earth. This solar wind is affected directly to Earth magnetosphere and ionosphere so that this bring out broadcasting and communication interruptions, satellite operation obstacles and power gird defects and etc..Solar wind flow in interplanetary space is measured as solar wind speed, density and direction by measuring scintillation value to be produced during radio source is passed through solar wind. The wider effective collective areas and the more radio sources, accuracy of solar wind measuring is got higher. Function test was performed using 3 tiles which was manufactured as prototype. Restriction of quantity of tiles, test was performed to confirm whether measured beam pattern is complied with requirement or not. In this paper, it is shown design and their specification of ground interplanetary radio measurement system as well as technical issues and resolutions which were raised during design phase. Also result of function verification test using prototype is suggested. It is confirmed that measured beam pattern was met with requirement.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.446-457
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• 2020

Crescentic sand bar in the coastal zone of eastern Korea is a common morphological feature and the rhythmic patterns exist constantly except for high wave energy events. However, four consecutive typhoons that directly and indirectly affected the East Sea of Korea from September to October in 2019 impacted the formation of longshore uniform sand bar and overall shoreline retreats (approx. 2 m) although repetitive erosion and accretion patterns exist near the shoreline. Widely used XBeach to predict storm erosions in the beach is utilized to investigate the morphological response to a series of storms and each storm impact (NE-E wave incidence). Several calibration processes for improved XBeach modeling are conducted by recently reported calibration methods and the optimal calibration set obtained is applied to the numerical simulation. Using observed wave, tide, and pre & post-storm bathymetries data with optimal calibration set for XBeach input, XBeach successfully reproduces erosion and accretion patterns near MSL (BSS = 0.77 (Erosion profile), 0.87 (Accretion profile)) and observed the formation of the longshore uniform sandbar. As a result of analysis of simulated total sediment transport vectors and bed level changes at each storm peak Hs, the incident wave direction contributes considerable impact to the behavior of crescentic sandbar. Moreover, not only the wave height but also storm duration affects the magnitude of the sediment transport. However, model results suggest that additional calibration processes are needed to predict the exact crest position of bar and bed level changes across the inner surfzone.

• The Journal of Bigdata
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• v.7 no.2
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• pp.235-244
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• 2022

The rental history data of public bicycles in Seoul were analyzed to examine how pandemic phenomena such as COVID-19 caused changes in people's micro mobility. Data for 2019 and 2021 were compared and analyzed by dividing them before and after COVID-19. Data were collected from public data portal sites, and data marts were created for in-depth analysis. In order to compare the changes in the two periods, the riding direction type dimension and the rental station type dimension were added, and the derived variables (rotation rate per unit, riding speed) were newly created. There is no significant difference in the average rental time before and after COVID-19, but the average rental distance and average usage speed decreased. Even in the mobility of Ttareungi, you can see the slow rhythm of daily life. On weekdays, the usage rate was the highest during commuting hours even before COVID-19, but it increased rapidly after COVID-19. It can be interpreted that people who are concerned about infection prefer Ttareungi to village buses as a means of micro-mobility. The results of data mart-based visualization and analysis proposed in this study will be able to provide insight into public bicycle operation and policy development. In future studies, it is necessary to combine SNS data such as Twitter and Instagram with public bicycle rental history data. It is expected that the value of related research can be improved by examining the behavior of bike users in various places.

• Journal of the Economic Geographical Society of Korea
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• v.27 no.3
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• pp.155-173
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• 2024

Using Regional Employment Survey, this article analyzes the widening employment gap between Capital and Non-Capital regions since the 2008 global financial crisis through describing the spatial distribution of employment by industry and occupation, calculating the regional downward employment rate of university graduates, and estimating the regional distribution of employment growth in terms of wage distribution, and then statistically analyzes the effect of the declining manufacturing employment in the Non-Capital region since the mid-2010s on total employment change. The results from these analyses are as follows. First, since the mid-2000s, the share of producer services and white-collar jobs has increased in the Capital region. Second, the Non-Capital region has a higher share of non-regular workers relative to wage workers than the Capital region. Third, while the downward employment rate has increased in the Non-Capital region since the mid-2010s, it has risen very modestly or stagnated in the Capital region. Fourth, in terms of wage distribution, the pattern of employment growth since the mid-2010s has been U-shaped, a typical polarized pattern of simultaneous growth in low- and high-wage jobs and decline in middle-wage jobs in the Non-Capital region, while in the Capital region it has been L-shaped with the sides reversed, driven by growth in high-wage jobs. Fifth, this employment polarization in the Non-Capital region since the mid-2010s is associated with employment changes in manufacturing, which accounts for a large share of middle wage jobs. Finally, according to the analysis of the effect of regional manufacturing employment changes on total employment changes since the mid-2010s, declines in manufacturing employment reduce the region's regular employment rate and have a larger negative employment effect in the Non-Capital region. Based on these findings, some policy issues are discussed including the branch plant economy regime based on spatial separation of conception and execution, the mix of geographic and skill mobility, the need to improve employability and jobs through human capital accumulation, and short- and long-term responses to employment fluctuations.

• Spatial Information Research
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• v.20 no.4
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• pp.69-82
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• 2012

The purpose of this study was to identify structural properties of C.B.D and to provide direction that required for the plan and its development by analyzing land use patterns and its characteristics in the center of the city. In this study, the future planning elements and detailed land use of Seoul was analyzed, in regard to the spatial structural hierarchy and the function of downtown, by investigation of its current urban spatial structure. First, the characteristic of the land-use for merchandising facilities is that it is developed from west to east along the Jong-ro, Myungdong and Namdaemun, it shows high rate of the facilities along the horizontal axis. The large market area on this district would be the reason to the high rate of mechandising facilities. Second, the characteristic of the land-use for business facilities is that it is highly rated on the area passing through the Sejong-ro and Seoul station. The analysis result of our investigation is that the projects executed by Seoul city such as 'downtown maintenance planning' and 'downtown recreation program' strengthened functions of business and merchandising and promoted downtown shopping, leisure, tourism functions resulting activation of nearby market place and evaluated as maintaing the centrality of downtown Seoul well.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.414-422
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• 2011

The paper is for top and bottom symmetrical phase controlled loop antenna using for multi-media devices. We developed a top and bottom phase control loop pattern arrangement methods for loop antenna in mobile devices like as a cell phone and PCS, WCDMA. In the loop antenna pattern, arrange close adhesive the loop antenna pattern $180^{\circ}$ cycle in wave length, the radiated electro-magnetic wave from close adhesive loop pattern in $180^{\circ}$ become to coherent wave than the phase controlled loop antenna has high efficiency and high radiation gain. To acquire a wide band width on phase controlled loop antenna, we arrange a top and bottom symmetrical architecture loop pattern that bas a $180^{\circ}$ wave length in each layer. Top and bottom each layer bas a U form pattern separated $90^{\circ}$ wave length each other. This architecture cause a well balanced electro-magnetic flow control that acquired wide bandwidth resonance response in loop pattern antenna. In experiment, we designed a WCDMA mobile multi-media antenna in $40mm{\times}6mm$ area thickness 0.2mm, in that passive experiment the radiation efficiency is over 50% and over 0dBi radiation average gain was acquired, in the active experiment in real multi-media device we acquired -4dBi average gain and 43% transmit/receive efficiency.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.3
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• pp.379-395
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• 2006

The purpose of this study is to analyze the spatial characteristics of travel patterns and travel behaviors of transit users in the Metropolitan Seoul area. We apply the data mining techniques to explore the travel patterns of transit users from the T-money card database which has been produced over 10,000,000 transaction records per day. The database contains the information of locations and times of origin, transfer, and destination points for each transaction as well as the informations of transit modes taken via the transaction. We develop an data mining algorithm to explore traversal patterns from the enormous information. The algorithm determines the travel sequences of each passenger, and produce the volumes of support on each points (stops) of transportation networks in the Metropolitan Seoul area. In order to visualize the spatial patterns of travel demands for transit systems we apply GIS techniques, and attempt to investigate the spatial characteristics of travel patterns and travel demand. Subway stops located in the Gangnam area appear the highest peak for the travel origin and destination, while the CBD in the Gangbuk stands at the second position. Two or three sub-peaks appear at the densely populated residential areas developed as the high-rise apartment complex. Subway stations located along the Subway Line 2, especially from Guro to Samsung receive heavy travel demand (total support), while bus stops located at the CBD in the Gangbuk stands the highest travel demand by bus.

• Journal of The Korean Association of Information Education
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• v.20 no.4
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• pp.387-400
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• 2016

In preparation for the adoption of software(SW) education in Korea by 2018, this study examined Korean teachers' perceptions and attitudes toward SW education and their relationship with teacher characteristics. By using the Stages of Concern Questionnaire, we conducted a survey of 92 teachers who participated in an introductory level of SW teacher training. The findings indicated that 1) the teachers' profile follows the typical nonuser pattern focusing on more self-concern, with the strongest intensity at Stage 0-Unconcerned and 1-Informational concern and the lowest at Stage 4-Consequence. However, teachers' stages of concern differed from the teachers' characteristics. Male teachers exhibited more concerns at Stage 4-Consequences, Stage 5-Collaboration, and Stage 6-Refocusing than female teachers. In addition, the teachers with higher SW proficiency, SW training experiences, and longer SW teaching experience showed higher intensity at Stage 4, 5, and 6 than their counterparts. The study suggests that the implementation of SW education would be effective and facilitated when teachers receive on-going and appropriate interventions and educational supports based on their individual concerns.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.3
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• pp.31-38
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• 2005

This paper proposes an implementation method of intelligent characters that can properly adapt to action patterns of opponent characters in fighting games by using genetic algorithm. For this intelligent characters, past actions patterns of opponent characters should be included in the learning process. To verify the effectiveness of the proposed method, two types of experiments are performed and their results are compared. In first experiment(exp-1), intelligent characters consider current action and its step of an opponent character. In second experiment (exp-2), on the other hands, they take past actions of an opponent characters into account additionally. As a performance index, the ratio of score obtained by an intelligent character to that of an opponent character is adopted. Experimental results shows that even if the performance index of exp-1 is better than that of exp-2 at the beginning of stages, but the performance index of exp-2 outperforms that of exp-1 as stages go on. Moreover, optimum solutions are always found in all experimental cases in exp-2. Futhermore, intelligent characters in exp-2 could learn moving actions (forward and backward) and waiting actions for getting more scores through self evolution.