• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.229-236
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• 2019

This study proposes a DC-DC converter topology of solid-state transformer for low-voltage DC distribution. The proposed topology consists of a voltage balancer and bipolar DC-DC converter. The voltage and current equations are obtained on the basis of switching states to design the controller. The open-loop gain of the controller is achieved using the derived voltage and current equations. The controller gain is selected through the frequency analysis of the loop gain. The inductance and capacitance are calculated considering the voltage and current ripples. The prototype is fabricated in accordance with the designed system parameters. The proposed topology and designed controller are verified through simulation and experiment.

• Smart Structures and Systems
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• v.33 no.6
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• pp.431-447
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• 2024

The Hybrid Mass Damper (HMD) has proven effective in mitigating vibrations in high-rise structures subject to seismic and wind-induced excitations. One derivative configuration of the HMD mounts an Active Mass Damper (AMD) atop a Tuned Mass Damper (TMD). However, the control efficacy of such HMDs may be compromised when confronted with loads that exceed their design parameters. Additionally, the confined structural space within high-rise structures often limits the feasibility and economic viability of retrofitting HMD systems. This study introduces an Acceleration-based Fuzzy Power Approach Rate Sliding Mode Control (AFP-SMC) algorithm aimed at enhancing the control efficacy of HMDs while minimizing their stroke and force output requirements. Employing the Canton Tower as a research prototype, an analytical model incorporating HMDs was established, and a comparative analysis between the AFP-SMC and Linear Quadratic Gaussian (LQG) control algorithms was conducted for efficacy. The control performance of the AFP-SMC control algorithm under different control parameter variations was investigated. Furthermore, by experimentally assessing the AMD subsystem within the Canton Tower, friction and ripple force formulas were derived to bolster the analytical model, thereby validating the robustness of the AFP-SMC algorithm. The results show that the proposed AFP-SMC algorithm effectively reduces the vibration response of the structure and the stroke and control force output of HMDs, and exhibits superior overall control performance and robustness compared to the LQG algorithm.

• The Journal of Information Technology
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• v.10 no.3
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• pp.93-120
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• 2007

A Smart Home is a technically expanded from home network that gives us a comfortable life. But still there is a problem such as mal function of devices and intrusions by malicious parties since it is based on home network. The intrusion by malicious parties causes a critical problem to the individual's privacy. Therefore to take legal actions against to the intruders, the intrusion evidence collecting and managing technology are widely researched in the world. The evidence collecting technology uses the system which was damaged by intruders and that system is used as evidence materials in the court of justice. However the collected evidences are easily modified and damaged in the gathering evidence process, the evidence analysis process and in the court. That's why we have to prove the evidence's integrity to be valuably used in the court. In this paper, we propose a mechanism for securing the reliability and the integrity of digital evidence that can properly support the Computer Forensics. The proposed mechanism shares and manages the digital evidence through mutual authenticating the damaged system, evidence collecting system, evidence managing system and the court(TTP: Trusted Third Party) and provides a secure access control model to establish the secure evidence management policy which assures that the collected evidence has the corresponded legal effect.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.217-219
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• 2004

In recent years, the smart card is wifely applied for wireless communication, tracking, transportation logistics, diagnostic monitoring, access control and security. RF-ID system is universally applicable. Passive RF-ID system consists from reader and passive tag. The reader transmits energy and simple information to a tag by wireless and the power from the reader is transformed for controller, FRAM and Bluetooth module. in this paper, an analysis and design of smart card for the transmission of the car movement data is presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.607-612
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• 2017

IT convergence with agriculture and livestock farming are expected to bring more efficiency and quality improvement in producing, distributing, consuming of agricultural products with the aid of information processing and autonomous control technologies of the IT area. The standardization work for smart farming and livestock farming based on networks is just at the beginning stage. And also, it is capable of coping with environment and technical problems with the actualized IT convergence case for agriculture. Hence, more studies on each point are required to finish the works including amendments and enhancements. More interests are expected to attain the successful results that ultimately contribute to innovate in the lifestyle. In this paper, it is analyzed strategy item and consider the actualized IT convergence case for agriculture and livestock, namely Smart Farming and Smart livestock Farming as a solution to cope the presented problems. In addition, suggest to ICT standardization road map for future planning.

• Smart Structures and Systems
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• v.2 no.1
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• pp.61-80
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• 2006

The concept of structural vibration control is to absorb vibration energy of the structure by introducing auxiliary devices. Various types of structural vibration control theories and devices have been recently developed and introduced into mechanical systems. One of such devices is damper employing controllable fluids such as ElectroRheological (ER) or MagnetoRheological (MR) fluids. MagnetoRheological (MR) materials are suspensions of fine magnetizable ferromagnetic particles in a non-magnetic medium exhibiting controllable rheological behaviour in the presence of an applied magnetic field. This paper presents the modelling of an MRfluid damper. The damper model is developed based on Newtonian shear flow and Bingham plastic shear flow models. The geometric parameters are varied to get the optimised damper characteristics. The numerical analysis is carried out to estimate the damping coefficient and damping force. The analytical results are compared with the experimental results. The results confirm that MR damper is one of the most promising new semi-active devices for structural vibration control.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.392-397
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• 2015

Recently computer games have been widely spread. For the purpose of studying brain activities, EEG was measured during the computer game and analyzed in terms of channels and frequency bands. EEG data were obtained during the resting state and game immersion. Then the power spectra of alpha, beta and theta bands were computed. During game immersion, the ratio between theta / alpha could effectively differentiate between rest and game immersion. Changes in brain activity (26~53%) were observed in the parietal and occipital lobes. Interestingly, immersion shows different features compared to concentration. The state of game immersion could be detected. Therefore, it is possible to utilize the state of immersion as one of the game parameters or to generate a control signal that may be used to provide a warning message or abort the game when the situation of the excessive indulgence in the game reaches. EEG can be applied as smart interface for computer game.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.3B
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• pp.212-219
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• 2002

In this paper, how to perform beamforming and power control for the systems with smart antennas is introduced in consideration of macro-diversity, and cell capacity of the systems is analyzed. In the result, as the number of the base stations linked to mobiles increases, capacity increases in the reverse link. On the other hand, macro diversity causes capacity loss in forward link. It is expected that the result of this work may be used in designing the next generation mobile communication systems for high quality services such as multi media data and wireless internet etc.

• Journal of Drive and Control
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• v.19 no.4
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• pp.54-61
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• 2022

This is a basic study analyzing emissions of an agricultural tractor during tillage operations. In this study, CO, THC, NOx, and PM considered as emission factor were analyzed during plow and rotary tillage operation by the tractor. Engine torque and rotational speed were measured through ECU. Engine power was calculated using engine torque and rotational speed. The emissions was calculated based on the number of units, rated power, load factor, and operating time. Results showed that the load factor was calculated almost twice, which was higher than 0.48. It was also observed that the emission of the tractor was variable for different agricultural operations because tractor loads were different based on operations. There was a difference in emissions due to differences in plow and rotary working hours. To estimate the emission of agricultural tractor based field operations in detail, it is necessary to consider TAF (Transient Adjustment Factor) and DFA (Deterioration factor). In the future, TAF and DFA will be considered to estimate emissions of the agricultural tractor. Finally, results of this study can contribute to the literature to estimate tractor emissions accurately.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.44-52
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• 2003

Shape memory alloys (SMA) are often used in smart structures as active components. Their ability to provide large recovery forces and displacements has been useful in many applications, including devices for artificial muscles, active structural acoustic control, and shape control. Based on the 3-dimensional SMA constitutive equation in this paper, the radial displacement control of externally pressurized circular and semicircular composite cylinders under external pressure with a thin SMA layer bonded on its inner surface or inserted between composite layers in investigated using 3-dimensional finite element analysis. Upon actuation through resistive heating, SMAs start to transform from martensitic into austenitic state, simultaneously recover the prestrain, and thus cause the composite cylinders to go back to their original shapes of the cylinder cross-sections.