• Ocean Systems Engineering
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• v.13 no.4
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• pp.349-365
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• 2023

Targeting a floating wave and offshore wind hybrid power generation system (FWWHybrid) designed in the Republic of Korea, this study examines the impact of the interaction, with multiple wave energy converters (WECs) placed on the platform, on platform motion. To investigate how the motion of WECs affects the behavior of the FWWHybrid platform, it was numerically compared with a scenario involving a 'single-body' system, where multiple WECs are constrained to the platform. In the case of FWWHybrid, because the platform and multiple WECs move in response to waves simultaneously as a 'multi-body' system, hydrodynamic interactions between these entities come into play. Additionally, the power take-off (PTO) mechanism between the platform and individual WECs is introduced for power production. First, the hydrostatic/dynamic coefficients required for numerical analysis were calculated in the frequency domain and then used in the time domain analysis. These simulations are performed using the extended HARP/CHARM3D code developed from previous studies. By conducting regular wave simulations, the response amplitude operator (RAO) for the platform of both single-body and multi-body scenarios was derived and subsequently compared. Next, to ascertain the difference in response in the real sea environment, this study also includes an analysis of irregular waves. As the floating body maintains its position through connection to a catenary mooring line, the impact of the slowly varying wave drift load cannot be disregarded. To assess the influence of the 2^nd-order wave exciting load, irregular wave simulations were conducted, dividing them into cases where it was not considered and cases where it was included. The analysis of multi-degree-of-freedom behavior confirmed that the action of multiple WECs had a substantial impact on the platform's response.

• Journal of the Korean Institute of Navigation
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• v.15 no.2
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• pp.39-47
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• 1991

As per the rapid development of world economics the marine traffic volume was increased accordingly and caused frequent disasters in human lives and natural environment in the consequence of accidents. As the result of the above they started to establish Vessel Traffic System(VTS) and separation scheme in waterway from 1960' to prevent the marin traffic accident but the problem of safety at sea appears now as neither fully defined nor sufficiently analysed. At the present, the dominant factor in establishing the strategy of marine traffic has been safety of navigation concerning only with the ship, but the risk of society derives almost wholly from the nature of cargo. To measure the degree of danger for each ship there is suggested concept of safety factor numbers denoting the level of latent danger in connection with ship and her cargo. In this paper, where the strategy of VTS is put on controlling density of safety factor for control area. it suggested algorithms how to assign the vessels and also to get optimal sequence of vessels located to a sector in the sense of minimizing the passage delay. For the formulation of problem, min max and 0-1 programming methods are applied and developed heuristic algorithm is presented with numerical example to improve the efficiency of calculation.

• Journal of the Korean housing association
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• v.17 no.4
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• pp.1-13
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• 2006

The purpose of the study was to identify the level of housing choice behavior by using the factors of residential satisfaction level, mobility motivation, and housing needs of potential purchasers in Bukgu New Housing Area, Ulsan. The survey used questionnaire from 326 households living in Bukgu and nearby area and analyzed using descriptive statistics. The research results showed low degree of residential satisfaction in storage space and neighborhood. The mobility motivations were improvement of physical environment improvement, education environment, walking road, view and lighting. The housing needs for indoor spaces showed to want more functional arrangement than the room size. The housing needs for outdoor spaces showed to want neighborhood environment in connection with the education or hospital facilities, the welfare facilities for pre-kindergarten children and elders and the leisure facilities. And the housing needs for facilities were floor furnishing for health, crime prevention system for safety needs, housekeeping appliance against environmental pollution, additional function for energy saving. The housing needs for common spaces showed that the residents preferred playing facilities by age group, exercise facilities, the community hall and the rest room which can do games or meetings.

• Journal of the Korean housing association
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• v.22 no.5
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• pp.37-46
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• 2011

Residential space has come to maintain a degree of specialization dependent upon the division of space according to function, while roles and functions have either expanded or ceased to exist corresponding to shifts in social values. However, various human behaviors connected to lifestyle habits and values are in fact becoming obsolete. This research will examine the mental, social, and functional aspects of the relationship between residential work spaces in modern homes and the sarangche as well as the communal space of daily and social life of the Chosun Dynasty to enhance the value and function of traditional residential space. As the boundary between family and work blurs with the home office environment of today, we are experiencing a deterioration of health and seeing problems in securing family domain as well as the prolonging of overwork. While the function of the traditional sarangchae encompassed a wider variety of activities than today's homes, the sarangchae achieved an efficient use of space divisions between rooms according to the particular purpose and situation. Accordingly, a reinterpretation of modern residential work space is needed through its connection to the sarangchae with consideration to the philosophy and values of the life of the noble class and the habits of our traditional lifestyle that have previously taken place within the sarangchae in an exterior space.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.4
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• pp.570-574
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• 2014

This paper proposes a wireless digital endoscope with a ultra-wide-angle view. Two key components are implemented to demonstrate the feasibility of the proposed endoscope. First, a ultra-wide-angle lens module with the field of view of 144 degree and F-number of 2.2 is designed and manufactured. Second, a wireless module for a high-speed video transfer is implemented using a USB device server and wireless LAN router. The wireless module can directly transfer a streaming video to a computer with the resolution of 1920x1080, frame rate of 30 fps, and data rate of 53.3 Mbps without an internet connection. Since the wireless module supports two USB devices, two spots can be simultaneously observed using the proposed endoscope.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1346-1349
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• 2004

In this paper, we have proposed the new link-weight calculating function using for routing decision in WDM networks. The proposed link-weight calculating functions includes following factors those are available wavelengths per link, distance loss, total wavelengths, and limited wavelength conversion. The calculated link-weight is applied into the algorithm of routing decision in order to determine the available lightpath that qualifies user requests. The objective is to improve the performance of wavelengths assignment with fast determining the suitable lightpath by using the proposed link-weights calculating function. The analytical model of WDM switching networks is introduced for numerical analysis. The link-weight calculating function is performed. Finally, the performance of proposed algorithm is displayed with numerical results in term of the blocking probability, the probability that connection requests from users are rejected due to there are no available lightpath to be assigned for them. It is also shown that the blocking probability is varied in depending on the number of available wavelengths and the degree of wavelength conversion. The numerical results also show that the proposed link-weight calculating function is more cost-effective choice for the routing decision in WDM switching networks.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.7
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• pp.685-696
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• 2011

An efficient laparoscope manipulator robot was designed to automatically control the position of laparoscope via a passive joint on end-effector position. The end position of the manipulator is controlled to have corresponding velocity defined in the global coordinate space using laparoscopic visual information. Desired spatial position of laparoscope was derived from detected positions of surgical instrument tips, then the clinical viewing plane was moved by visual servoing task. The laparoscope manipulator is advantageous for automatically maintaining clinically important views in the laparoscopic image without any additional operator. A laparoscope is mounted to a holder which is linked to four degree of freedom manipulator via universal joint-type passive rings connection. No change in the design of laparoscope or manipulator is necessary for its application to surgery assistant robot system. Expanded working space and surgical efficiency were accomplished by implementing slant linking structure between laparoscope and manipulator. To ensure reliable positioning accuracy and controllability, the motion of laparoscope in an abdominal space through trocar was inspected using geometrical analysis. A designed laparoscope manipulating robot system can be easily set up and controlled in an operation room since it has a few subsidiary devices such as a laparoscope light source regulator, a control PC, and a power supply.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.2
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• pp.240-253
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• 2012

In this paper we propose a protection mechanism for the debug port. While debug ports are useful tools for embedded device development and maintenance, they can also become potential attack tools for device hacking in case their usage is permitted to hackers with malicious intentions. The proposed approach prevents illicit use of debug ports by controlling access through user authentication, where the device generates and issues authentication token only to the server-authenticated users. An authentication token includes user access information which represents the user's permitted level of access and the maximum number of authentications allowed using the token. The device authenticates the user with the token and grants limited access based on the user's access level. The proposed approach improves the degree of overall security by removing the need to expose the device's secret key. Availability is also enhanced by not requiring server connection after the initial token generation and further by supporting flexible token transfer among predefined device groups. Low implementation cost is another benefit of the proposed approach, enabling it to be adopted to a wide range of environments in demand of debug port protection.

• Journal of the Korean Society of School Health
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• v.26 no.1
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• pp.34-44
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• 2013

Purpose: The purpose of this study is to identify the relationship between school adjustment and stress-coping styles among adolescents. Methods: This is a descriptive correlation survey using a convenience sample of 701 middle school students in Seoul, Gyeonggi, Incheon, Jeonbuk, and Gangwon province, Korea. The study's questionnaire included a scale of school adjustment and a scale of stress-coping style. The data analysis, using the SPSS 19.0 program, involved frequency, the mean and standard deviation, the t-test, ANOVA, the scheffe test, and the Pearson correlation coefficient. Results: Positive correlations were identified between positive stress-coping styles and the adjustment to school life of adolescents. The degree of school adjustment varied significantly according to the region, grade, attending private educational institutes after school or not, academic performance, daily study hours after school, and the hours students spend on gaming and Internet use a day. With regard to the behaviors to cope with stress, teenagers with a higher sense of life-satisfaction tended to show active coping behaviors, and female students were more likely to show positive or negative coping behaviors than mystic coping behaviors. Since adolescents' stress-coping styles showed connection with their adjustment to school, it is necessary to develop stress management programs to help middle school students adjust to school life. Conclusion: Based on the study's findings, it is important to develop programs which can help students adjust to school and learn how to cope with stress positively.

• Solar Energy
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• v.17 no.2
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• pp.3-11
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• 1997

In conventional heat and vent dryer, both sensible and latent heat could not be recovered from the exhaust air, but this problem could be solved by introducing a heat pump to a conventional dryer, having a connection with cooling, dehumidifying and heating of heat pump. In this work, HFC134a as a substitute refrigerant of CFC12 adopted in heat pump and a batch type is also introduced. The variables affected on the system performance are holding temperature of a drying chamber, bypass air ratio, degree of superheat and refrigerant flowrate, etc. The moisture contents were decreased curvilinearly in the range of $86{\sim}75%$ on the wet basis. Under the constant drying temperature, the face velocity plays an important role to the drying performance. The COPs are increased in accordance with the air velocity, on the other hand the SMERs are gradually decreased.