• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.837-844
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• 2017

The weir to regulate water level in a tide generation tank is above and below carried by two electric cylinders which are mounted on right and left of weir itself. In this case, a movement difference between right and left cylinder causes unbalance of weir and friction between weir and guide. And then, the weir will not be sent to target point. In this study, a synchronous control system is developed to take accurate and quick equilibrium of the weir. The control system based on cross coupled structure consists of two I-PD controllers and a lead compensator. Each of the I-PD controllers is designed in order that the electric cylinder may exactly follow the reference signal without overshoot and input saturation. And the lead compensator is designed to achieve stable and accurate synchronization. Finally, the simulation result shows that the designed synchronous control system is effective for elimination of synchronous error.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.68-74
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• 2018

All transparent UV photodetector based on ZnO was fabricated with structure of NiO/ZnO/$SnO_2$/ITO by using RF and DC magnetron sputtering system. ZnO was deposited with 4 inch ZnO target (purity 99.99%) for a quality film. In order to build p-n junction up, p-type NiO was formed on n-type ZnO by using reactive sputtering method. The indium tin oxide (ITO) which is transparent conducting oxide (TCO) was applied as a transparent electrode for transporting electrons. To improve the UV photodetector performance, a functional $SnO_2$ layer was selected as an electron transporting and hole blocking layer, which actively controls the carrier movement, between ZnO and ITO. The photodetector (NiO/ZnO/$SnO_2$/ITO) shows transmittance over 50% as similar as the transmittance of a general device (NiO/ZnO/ITO) due to the high transmittance of $SnO_2$ for broad wavelengths. The functional $SnO_2$ layer for band alignment effectively enhances the photo-current to be $15{\mu}A{\cdot}cm^{-2}$ (from $7{\mu}A{\cdot}cm^{-2}$ of without $SnO_2$) with the quick photo-responses of rise time (0.83 ms) and fall time (15.14 ms). We demonstrated the all transparent UV photodetector based on ZnO and suggest the route for effective designs to enhance performance for transparent photoelectric applications.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.515-521
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• 2007

To increase the stevedore efficiency and service level at container terminal, it is essential to reduce working time of container crane which has a bottle neck in the logistic flow of container. The working speed and safety are required to be improved by controlling the movement of the trolley as quick as possible without big overshoot and any residual swing motion of container in the vicinity of target position. This paper presents optimal state feedback control using RCGAs in the case of existing constrained conditions

• The Journal of Society for e-Business Studies
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• v.22 no.4
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• pp.103-115
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• 2017

Globally, frequency and scale of natural disasters are growing, also the damage is increasing. In view of the damage by natural disasters for several years, it is true that Korea is not free from such damages. In this paper, we propose a process to efficiently manage recovery resources in case of disaster damage. We utilize the IoT technology to detect the resource status in real time, and configure the process so that the state and movement of the recovery resource can be grasped in real time through the resource activity recognition module. In addition, we designed the database that is necessary to actualize it, and developed and experimented resource activity recognition module using smart-phone sensors. This will contribute to building a quick and efficient disaster response system.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.1
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• pp.56-63
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• 2003

This paper introduces a vision based autonomous mini mobile robot that is an approach to produce real autonomous vehicle. Previous autonomous vehicles are dependent on PC, because of complexity of designing hardware, difficulty of installation and abundant calculations. In this paper, we present an autonomous motile robot system that has abilities of accurate steering, quick movement in high speed and intelligent recognition as a stand-alone system using a mono camera. The proposed system has been implemented on mini track of which width is 25~30cm, and length is about 200cm. Test robot can run at average 32.9km/h speed on straight lane and average 22.3km/h speed on curved lane with 30~40m radius. This system provides a model of autonomous mobile robot adapted a lane recognition algorithm in odor to make real autonomous vehicle easily.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.719-728
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• 2009

In this study, a training program was conducted to improve the performance of the basic movement of the basket-to-handstand mount. After completion of the training program, the kinematic comparison of the before and after effects were investigated to provide scientific data about this technique. It is recommended that during P1, the center of body mass at the back should push the hip joint to flex quickly, and the shoulder joint should be maintained at a maximum angle. During P2, the body's center of mass must be accelerated so as to create enough momentum to rise efficiently for this, quick extension of both the hip and the shoulder is required. For safety during P3, it is advised that the speed upwards must be increased and that the hands, shoulders, and hip joint must be extended, as in the posture of a handstand. These results stress to coaches the importance of the bodies speed during the ascent in the motion.

• Journal of the Korean Geosynthetics Society
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• v.10 no.1
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• pp.43-51
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• 2011

Pile-supported embankment is one of the reinforcing methods to minimize damage due to the severe subsidence and lateral flow when soft clay ground is supported with embankment. pile-supported embankment mainly penetrates soft ground into the bearing stratum in order to support surcharge load which minimizes the subsidence and lateral flow due to the surcharge load. The aim of this research is to review quantitatively reinforcing effect of pile-supported embankment which is installed in soft clay ground. From the model test, it reproduced the ground movement with regard to the non-reinforced and reinforcing embankment-pile and also analyzed stabilizing effects of lateral flow due to the pile-supported embankment. With regard to the case of installing pile-supported embankment, its were analyzed stabilizing effects of lateral flow in cases of quick-load and slow-load to make different surcharge load.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.117-130
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• 2013

It is a difficult thing to administer a various task in the construction site because, the person placing an order are eagerly demanding for the reduction of project duration as the trend of construction are becoming larger and international. The advanced country have made an effort to development PMIS based on the Web, which to exchanges a various construction information such as Time Management/Construction Management/Resource Management/Document Management to solve these problems since 2000. However, the expectation to develop a smart PMIS that can deal with a more quick change of a various process are becoming lager as the lively supply of IT equipment such as smart phone and table PC. The research are aim to develop the next generation smart PMIS, which is link with the table PC and smart phone for a site manager to use the system based on the web in the movement. Also, it has an object in view to introduce the development process and the major function of the next generation PMIS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.5
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• pp.303-313
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• 2019

After a disaster happens in urban areas, many people need support for a quick evacuation. This work aims to develop a method for the calculation of the most feasible evacuation route inside buildings. In the methodology we simplify the geometry of the structural and non structural elements from the BIM (Building Information Modeling) to store them in a spatial database which follows standards to support vector data. Then, we apply the multicriteria analysis with the allocation of prioritization values and weight factors validated through the AHP (Analytic Hierarchy Process), in order to obtain the Importance Index S(n) of the elements. The criteria consider security conditions and distribution of the building's facilities. The S(n) is included as additional heuristic data for the calculation of the evacuation route through an algorithm developed as a variant of the $A^*$ pathfinding, The experimental results in the simulation of evacuation scenarios for vulnerable people in healthy physical conditions and for the elderly group, shown that the conditions about the wide of routes, restricted areas, vulnerable elements, floor roughness and location of facilities in the building applied in the multicriteria analysis has a high influence on the processing of the developed variant of $A^*$ algorithm. The criteria modify the evacuation route, because they considers as the most feasible route, the safest instead of the shortest, for the simulation of evacuation scenarios for people in healthy physical conditions. Likewise, they consider the route with the location of facilities for the movement of the elderly like the most feasible in the simulation of evacuation route for the transit of the elderly group. These results are important for the assessment of the decision makers to select between the shortest or safest route like the feasible for search and rescue activities.

• Journal of Navigation and Port Research
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• v.47 no.2
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• pp.106-119
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• 2023

Due to global decarbonization movement and tightening of maritime emissions restrictions, the shipping industry is going to switch to alternative fuels. Among candidates of alternative fuel, methanol is promising for decreasing SOx and CO2 emissions, resulting in minimum climate change and meeting the goal of green shipping. In this study, a novel combined system of direct methanol solid oxide fuel cells (SOFC), proton exchange membrane fuel cells (PEMFC), gas turbine (GT), and organic Rankine cycle (ORC) targeted for marine vessels was proposed. The SOFC is the main power generator of the system, whereas the GT and PEMFC could recover waste heat from the SOFC to generate useful power and increase waste heat utilizing efficiency of the system. Thermodynamics model of the combined system and each component were established and analyzed. Energy and exergy efficiencies of subsystems and the entire system were estimated with participation of the first and second laws of thermodynamics. The energy and exergy efficiencies of the overall multigeneration system were estimated to be 76.2% and 30.3%, respectively. The combination of GT and PEMFC increased the energy efficiency by 18.91% compared to the SOFC stand-alone system. By changing the methanol distribution ratio from 0.05 to 0.4, energy and exergy efficiencies decreased by 15.49% and 5.41%, respectively. During the starting up and maneuvering period of vessels, a quick response from the power supply system and propulsion plant is necessary. Utilization of PEMFC coupled with SOFC has remarkable meaning and benefits.