• Journal of the Korea Computer Graphics Society
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• v.19 no.1
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• pp.21-25
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• 2013

In this paper, we consider a physics-based 2D flight simulation game where users can easily control realistic flight of a vehicle equipped with two thrusters that allow vertical takeoff and vertical landing. The flight vehicle can be manipulated by directly controlling the thrusting force at each thruster using a pair of analog input devices such as joysticks. However, it might require too much practice to make aerobatic flying solely with this kind of control. We propose a set of fly-by-wire methods that provide easy-to-use, intuitive control of a VTVL vehicle. Based on PD controllers, the proposed methods allow users to specify the velocity or position of the vehicle directly. Furthermore, they are easy to understand and simple to implement. We expect that the proposed vehicle model and control mechanism could be used in various 2D games.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.4
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• pp.165-171
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• 2018

In this study, the shape of the flow control structure within a DVR was designed for heat dissipation of the CPU. The proposed design consists of three thin metal plates, which directly controls the air flow inside the DVR box and forces the air to pass through the CPU, thereby efficiently dissipating heat from the CPU. The shape of the structure was determined using parametric studies. To verify the design result, we carried out a three-dimensional time dependent numerical analysis using a commercial fluid dynamics analysis package FlowVision. As a result of experiments with a real DVR equipment, it is confirmed that the temperature of the CPU is significantly reduced compared to the initial model.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.1
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• pp.37-45
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• 1994

A method of optimal active and reactive power control for economic operation in electrical power system is presented in this paper. The major features and techniques of this paper are as follows: 1) The method presented for obtaining the equivalent active power balance equation applying the sparse Jacobian matrix of power flow equation instead of using B constant as active power Balance equation considering transmission loss, and for determining directly optimal active power allocation without repeating calculations. 2) More reasonable and economic profit by minimizing total fuel cost of thermal power plants instead of using transmission loss as objective function of reactive Power control can be achieved. 3) Particularly in reactive power control, computing time can be considerably reduced by using Fuzzy Linear Programming instead of using conventional Linear Programming.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.62-71
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• 2009

In this paper, an improved drive method of piezoelectric PZT stack actuator for micro-positioning system is proposed and the performances are evaluated. This type of amplifier is based on switching technology efficiently handling the arbitrary regenerative energy from the piezoelectric actuator. The conventional voltage-feedback control method has the THD of -32dB (${\approx}2.5%$) with 100mHz sinusoidal reference, which means that the positioning performance in linearity degrades due to the hysteretic relationship between actuator voltage and the displacement. This paper proposed an improved charge-controlling method, which utilizes differential information of charge reference instead of integrating the actuator's current. The current waveform has THD under -40dBV (=1%) and the displacement waveform nearly -52dB (${\approx}0.25%$), which means that the positioning performance is very excellent. Finally, another method of the displacement feedback control has better performance than the voltage method, however there exists a limitation in performance of the system.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.69-73
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• 2014

Recent interest in the worldwide energy to increase, and energy savings of the energy for effective operation of the IT technology there is a demand. By using a low-power LED energy efficient energy use worldwide for a variety of studies have been conducted. In Korea, 20-30% of the domestic electricity consumption corresponding to the illumination in order to conserve energy used by various sensors associated with illumination control studies are underway. That is the next generation of energy began to pay attention to the LED light source, LED and Arduino In this paper, an ultrasonic sensor to control and want to maximize the energy efficiency of the management. Paper, the user is directly operating the separate controller that controls the LED light, instead of being recognized through human body detection LED light on / off to control the experiment and study verified. In this paper, we develop an interface that also allows them to maximize the efficiency of energy management and efficiency, accompanied by expansion of commercialization can be achieved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.188-194
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• 2006

Since the late 1920's possibility of commercial hydroponics was testified practically. Hydroponics is used as environmentally friendly agriculture production system recently with high effectiveness. Now that existing irrigation control systems such as time control or solar radiation control cannot satisfy stable water content in root substrates, the needs for new irrigation system keep increasing. In this paper, we proposed environmentally friendly automatic irrigation management system by employing automation system based on electronic control system, which could solve problems based on manual irrigation management system. In addition, it suggested to be applied to any crops and will be able to overcome existing limit in irrigation by measuring the water content of root substrate in realtime.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.4
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• pp.337-350
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• 2004

Because of a security problem and not enough IPv4 address space, the home network has been made up of private network, and it has been separated from Internet. This fact prevents people in Internet from controlling and monitoring home appliances. So, this paper designs and Implements the UPnP Proxy System which offers functions for users to control and monitor home appliances. When users are in the outside of the home network, they do not know which devices were connected in the home network because the advertisement messages of UPnP devices would not be delivered to the outside of the home network. Also, users cannot access devices directly, and their control messages are not delivered into the home network. So, this paper designs and implements the UPnP Proxy System to solve these problems. The merit of the system is that users can control and monitor home appliances in realtime using presentation web documents with the HTTP push technology.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.144-144
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• 2012

스퍼터링 기술은 타겟 사용 효율 및 증착률 향상 개념에서의 소스 특성향상과, 증착 기판으로 이동하는 스퍼터링 입자량 및 이온화율 제어를 통한 코팅 박막의 특성향상 등 크게 두 축을 중심으로 발전되어 왔다. 특히 소스 특성 향상 관점에서 고진공에서의 스퍼터링 기술, 듀얼 마그네크론 스퍼터링 및 무빙 마그네트론 스퍼터링 기술 및 원통형 스퍼터링 기술이 개발되어왔으며, 코팅 박막의 특성 향상과 관련하여서는 스퍼터링 방전 내 플라즈마의 밀도의 증대 및 기판 입사 입자의 에너지 제어를 통한 박막의 치밀도 향상 연구가 많이 이루어져, UBM 또는 ICP 결합 스퍼터링 및 Arc-스퍼터링 혼합공정이 연구되어 왔다. 박막 증착에서 박막의 물성을 조절하는 주요인자는, 기판에 입사하는 입자의 에너지로, 그 조절 범위가 좁고 넓음에 따라 활용 가능한 코팅 공정의 window가 설정된다. 지난 15년간 증착박막의 물성 향상을 위하여 스퍼터링 소스의 제어 관점이 아닌 전원적 관점에서 스퍼터된 입자의 에너지 제어를 MF(kHz), Pulse 전원 사용을 통해 이루어져 왔고, 특히 High Impulse Pulse를 이용한 HiPIMS 기법이 연구개발과 시장의 이해가 잘 어울려져 많은 발전을 이루고 있다. HiPIMS 공정은 박막의 물성을 제어하는 관점을 스퍼터링에 사용되는 보조 가스인 Ar 이온에 의존하지 않고, 직접 스퍼터된 입자의 이온화를 증대시키고, 이 이온화된 입자를 활용하여 증착 박막의 치밀성 및 반응성을 증대시켜, 박막특성을 제어하는 기술이다. HiPIMS의 경우, 초기 개발 당시에는 고에너지, 고이온화의 금속 이온을 대량 생성할 수 있다는 이론적 배경에서 연구되었다. 그러나 연구 개발이 진행되면서, 박막의 물성과 증착률 등 상반된 특성이 나타나면서 이에 대한 전원장치의 개량이나 스퍼터링 소스의 개선 등 다양한 개발 연구들이 요구되고 있다. 재료연구소에서는 스퍼터링 기술에서 가장 문제가 되고 있는 타겟 사용효율화 관점 및 스퍼트된 입자의 이온화률 증대에 대한 두 가지 문제를 동시에 해결할 수 있는 방안으로 고밀도 플라즈마를 이용한 스퍼터링 기술을 개발하고 있다. 본 발표에서는 이러한 HiPIMS의 연구 개발 동향과 고밀도 플라즈마를 이용한 스퍼터링 기술에 대한 연구 동향을 발표하고자 한다.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.27-34
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• 2018

In this study, the generating of torque regarding the Control Moment Gyro (CMG) is proportional to the angular velocity of gimbal. This is the case because gimbal affects the attitude control of the satellite directly, and it is necessary to reduce the incidence of torque ripple of gimbal. In this paper, the cause of the torque ripple of gimbal is reviewed and mathematically modeled by assuming the friction imbalance of bearing, the magnetic field and the phase current imbalance of the motor. We are able to confidently estimate the modeling parameters of gimbal disturbance using a constant speed test, and then analyze the influence of applying feedforward control to our modeling. Additionally, the simulation results show that the torque ripple and angular velocity fluctuations are reduced when apply this modeling to the identified study parameters. Finally, we present the disturbance reduction technique using our disturbance modeling.

• Smart Media Journal
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• v.12 no.7
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• pp.27-42
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• 2023

The development of cloud services and IoT technology has radically changed the cloud environment, and has evolved into a new concept called fog computing and F2C (fog-to-cloud). However, as heterogeneous cloud/fog layers are integrated, problems of access control and security management for end users and edge devices may occur. In this paper, an F2C-based IoT smart health monitoring system architecture was designed to operate a medical information service that can quickly respond to medical emergencies. In addition, a role-based service access control technology was proposed to enhance the security of user's personal health information and sensor information during service interoperability. Through simulation, it was shown that role-based access control is achieved by sharing role registration and user role token issuance information through blockchain. End users can receive services from the device with the fastest response time, and by performing service access control according to roles, direct access to data can be minimized and security for personal information can be enhanced.