• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.259-263
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• 2006

Development and maintenance of forests are very important at Korea which has mountainous topography of more than 60% of the national territory. Under the circumstances, variety period's data is being required for the continuous monitoring of forest area. In this study, change of forests type was analyzed using Landsat TM satellite image which have multi-spectral bands. Furthermore, change detection system for forests type was constructed on web for the periodical monitoring. By using this system, everyone can easily use for the monitoring of forest type's periodical change.

• Journal of the Korean Institute of Navigation
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• v.15 no.2
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• pp.87-96
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• 1991

The change of water level at Mokpo Harbour and its adjacent coastal area due to the construction of the Youngsan Estuary Barrage and the Third Land Reclamation Work of estuary barren had been roughly expected. Periodical floods, which occur 2 times per month, are also being observed at the low lying commercial areas near the Mokpo Old Harbor. Although it is said that the highest tidal current component among the tidal current records at the approaching channel to Mokpo Harbor is reduced to 6 kts, because of the esturary barrage, they do not give any precise statement or a deep analysis for the flooding and periodical water level change under certain environmental conditions. Moreover, they never tried the analysis of development plan considering the natural disaster such as typhoon or other extreme conditions. Thus, it is necessary to collect and analyze the data related to floodings, harbor oscillations, currents, and water quality , etc. because of the development considering the extreme condition. Thus, it is necessary to collect and analyze the data related to floodings, harbor oscillations, currents, and water quality, etc. because of the development considering the extreme condition and to evaluate the field observation and measurement, including the numerical model simulation based on the scientific approaches. This study deals the problem of the water level change among the integrated analyses of the coastal area changes. The result can be used for the integrated planning to give a strong foundation and it will contribute to the development of local area.

• The Research Journal of the Costume Culture
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• v.16 no.4
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• pp.735-747
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• 2008

This study was about the fashion model's images during the periods of time. Also, this was to know the model's role and fields they had worked in and to investigate the specializing courses to get advice from their diversities, specialties and activities. The method of the study was used the qualitative analysis from the relative books, theses from university graduates, the related society newsletters, fashion magazines that were printed periodical/non-periodical, and others. As a result, the glamourous image was the most famous in the twenties and thirties, and the elegant image mainly in the forties and fifths. The images were more diverse in the nineties through the girlish images of the sixties, and the sexy image with good health of the seventies and eighties. Baby faces became the ideal of models in the new century. The images of the models become popular and disappear rapidly due to the change of major trend with the change of the society's environment. Under the situation, they must take good care of their images and self-control themselves to keep a positive view of fashion models to the public, and they must have ambition as a fashion icon and make their own exclusive fields in various parts.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.3
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• pp.1-9
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• 2015

The purpose of this paper is to analysis on periodical changes of rural houses of Korean-Chinese people residing in Yanbian area, China focused on periodical changes of floor plans according to Chinese government's policies and regulations influencing on rural houses. Changes of floor plans are classified into four periods; immigrating settled period, 1960-1970s, 1980-1990s, and after 2000. Total number of 67 cases were analyzed that data was collected 48 cases of literature studies and 19 cases of field study in Yanbian, China. The results are as followings. In immigrating settled period, floor plans of the rural houses have tended to be continued the pattern of the Korean traditional rural houses. Nevertheless China was changed socialism system, rarely floor plans were influenced by the system during this period. From 1960s to 1970s, the livestock and rural mechanization are influenced by the "People's Commune" policy. The "Barn" and "Mill" were converted into "warehouse". The residential part consists of one Jeongji (space mixed dinning and kitchen) and one to three of Ondolbang (room). From 1980s to 1990s influenced by the policies of "Cultural Revolution", "Birth Control" and "Chinese Economic Reform", the Korean traditional customs like "elders first" and "distinction between the male and female have been gradually vanished. Meanwhile, spaces of the rural houses have consisted of Jeongji, big Utppang (room), and warehouse. Each space is opened and mutual. Since 2000, influenced by the policy of a "new Socialist Countryside Construction", the bathroom and kitchen are added in interior spaces, the life style in rural houses has been changed as for both the sedentary style and western style.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.138-141
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• 2003

Recently reinforcement learning has attracted attention of many researchers because of its simple and flexible learning ability for any environments. And so far many reinforcement learning methods have been proposed such as Q-learning, actor-critic, stochastic gradient ascent method and so on. The reinforcement learning system is able to adapt to changes of the environment because of the mutual action with it. However when the environment changes periodically, it is not able to adapt to its change well. In this paper we propose the reinforcement learning system that is able to adapt to periodical changes of the environment by introducing the time-varying parameters to be adjusted. It is shown that the proposed method works well through the simulation study of the maze problem with aisle that opens and closes periodically, although the conventional method with constant parameters to be adjusted does not works well in such environment.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.677-684
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• 2010

Backlashes of gears provide gears for good lubrication and for removal of the interference between teeth by the wear and manufacturing errors. The backlash is the strong nonlinear factor to gears. This study deals with nonlinear modeling of helical gears with backlash. Excitation of helical gears comes from torque variation, the tooth surface error, and the periodical change of mesh stiffness. To study the effect of torque fluctuation, equation of motion for the single degree of freedom torsional model of helical gears with the periodical change of mesh stiffness and the backlash was derived. The Newmark beta method and the Newton-Raphson method were used to obtain the nonlinear behaviors of mesh forces of helical gears. All excitation frequencies initially caused the tooth separation and single-sided impacts of the gear pair and eventually led to the normal tooth contact. However, some special excitation frequencies caused the single-sided impacts in the entire time as well as the initial time. Damping increase reduced the duration of single-sided impacts, and the backlash increase caused those in the entire time domain.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.397-407
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• 2016

This study analyzed the efficiency change and the factors affecting productivity change for the six railway operation corporations that are local public enterprises; study was performed with the DEA-CCR Model and Malmquist Productivity Index, using data collected from 2010 to 2014. Since it was not feasible to collect data on the operating expenses and the number of employees of each of the lines, the efficiencies of each operation corporation were analyzed by integrating the operation corporations, and the Malmquist Productivity Index was used to investigate the trend of the periodical productivity change. Average efficiency for urban railway operation corporations was found to be higher in the case of the bigger corporations. In 2014, the Seoul Metro and the Daejeon Metropolitan Express Transit Corporations were analyzed and found to be the most efficient operation corporations. The Malmquist Productivity Index was used to determine the periodical change; the average MPI was 1.06, with a continuous increase of productivity. The analysis showed that changes of technology were generally more obvious than change of technology efficiency for all six operation corporations.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.4
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• pp.55-65
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• 2012

Urban traditional housing is a type of the urban housing which have developed by itself from the traditional vernacular houses and it has continued with a traditional feature in the westernization and modernization affection of Korea. Also, the urban traditional housing is still one of the housing in the present and it makes a urban village with a rich culture benefit and fresh natural environment. The purpose of this study is to analyze the periodical characteristics of urban traditional house in korea's provincial town Gyeongju. The local range is Hwang-Nam Hanok Conservation Area in Gyeongju and the period range is 1874~2000s. So the first period from 1874 to 1909, the second period is 1910 to 1945, the third period is 1946 to 1969, the fourth period is 1970s, and the fifth period is since the 1980s. This classification will be considered of the social phenomenon at the time. The total number of target houses are 8 houses. They were analyzed by layout, floor plan, and elevation characteristics of urban traditional house. For structure of this study, Chapter 1, establishes the goal and range of study. Chapter 2, 3, examines distinctions of urban traditional house with traditional house, and meaning of urban traditional house, and transition of urban traditional house. Chapter 4, establishes formality to analysis, and performed from plan to elevation analysis, observation survey, and interview through door-to-door survey, and clarifies trend and characteristic of urban traditional house's change by integrating the results, and Chapter 5, is results integrating the above studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1353-1356
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• 2009

As a method obtaining linear thrust force for the magnet wheel producing a strong traction torque, the concept of magnetic shield is suggested and compared with the existing approaches. Specially, as the magnet wheel, in which the permanent magnets rotate mechanically instead of ac driving to make traveling field, is physically similar with the rotary induction motor, there is a periodical force ripple in tangential direction as well as normal direction. But, the force ripple can be suppressed from a shape change of the shield plate. Namely, the change brings out a change of entry and exit effect of the circumferential field for the magnet wheel. The feasibility of the shield concept is verified from simulation and experiment.

• Journal of the Korean Society of Costume
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• v.52 no.1
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• pp.159-173
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• 2002

The subject of the paper is for the study about the implication and the changes of design and functions in the underwear by the change of the times from late 19c until present time. Researching on documents and magazine's articles, and interviewing with women older than 60s is used for the period of previous 1960s. researching on documents, advertising, newspaper, and interviewing with the persons concerned is used for the period of after 1960s. Analysis showed periodical change in underwear is divided into that the changes of the time is divided into 1890-1950 start to Westernization in underwear, 1957-1969 Ready made in underwear. 1950-1969 Variety in underwear, 1980-1989 Fashioning, functioning in underwear, 1990-present Withdrawing from fundamental notion in underwear. The time of 1890-l950 showed the biggest change in an external form in underwear. In 1950-1969, notions of beauty in underwear ultimately swatch from Oriental sense to Western sense, In 70s, underwear achieved the early stage of fashioning. In 80s, Underwear became one of fashion item. In 90s, underwear achieved higher quality and variety. The basic notion of underwear was destroyed by exposing underwear.