• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.1051-1057
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• 2013

In this study, an automatic surface-strain measurement system called "ASIAS-bio" has been developed. This system can be used even in cases in which it is very difficult to apply a regular grid pattern necessary for measuring surface-strain, such as curved or uneven surfaces; surfaces damaged by corrosion or contamination; or soft materials such as rubber, foam, and biological tissues. This system works independently of the measurement conditions including the material and its surface condition, grid pattern and size, grid marking method, and degree of deformation. A comparison between the strain distributions of the sheet metal parts measured by using this system and those obtained by a commercial system showed that this system was sufficiently reliable. In addition, the deformation of the swine joint capsule and human knee skin was measured by using this system to demonstrate its usefulness.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.435-444
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• 2013

ATSC terrestrial DTV system can support high data rates for HDTV(High Definition Television) service, but it suffers from significant performance degradation caused by multipath fading. Thus, it is necessary to analyze multipath fading effects in order to enhance the DTV reception performance. Generally, DTV channel profile can be obtained by auto-correlation between reference pseudo random signal and received DTV signal. However, in the ATSC terrestrial DTV system, the estimation performance of DTV channel profile may be decreased due to the VSB modulation features. In this paper, improved DTV channel profile measurement technique is analyzed and proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4341-4348
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• 2012

This paper presents a web-based real-time monitoring system for a photobioreactor using an WiFi wireless network. An WiFi interface can support high speed data transfer, up to 11Mbps and it can be compatible with commercial wireless LAN environment. Thus, the proposed cell culture based on WiFi network can be easily applied to the reconfigurable system and real-time monitoring system. In this paper, we integrate the commercial WiFi module to the various bio-sensors and sensor control board to configure the wireless network. After we evaluate application S/W for monitoring the environment within incubator, we verify the proposed sensor networks for a cell culture system and its monitoring system. This result can be applicable for various bio-applications that require the network configuration and real-time monitoring system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1036-1055
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• 1992

In this paper the feedback linearization of the valve-controlled nonlinear hydraulic velocity control system and the implementation of the digital state feedback controller is studied. The $C^{\infty}$ nonlinear transfomation to the electro-hydraulic velocity control system, which transforms nonlinear system to linear equivalent one, is obtained. It is shown that this transformation is global one. The digital controller to this linearized model is obtained by using the one-step ahead state estimator and implemented to real plant. The proposed implementation method is easier than the other proposed methods and it is possible to control in real time. The experiment and simulation study show that the implementation of the digital state feedback controller based on the feedback linearized model is successful..

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.475-481
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• 2014

The aim of this work was to develop the gamma camera system for small animal gamma imaging and environmental radiation monitoring imaging using a parallel hole collimator and pinhole collimator. The small gamma camera system consists of a CsI(Tl) scintillation crystal with 6 mm in thickness and $50{\times}50mm$ in area coupled with a Hamamatsu H8500C PSPMT, are resistive charge divider, pre-amplifiers, charge amplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a computer for control and display. We have developed a radiation monitoring system composed of a combined pinhole gamma camera and a charge-coupled devices (CCD) camera. The results demonstrated that the parallel hole collimator and pinhole collimator gamma camera designed in this study could be utilized to perform small animal imaging and environmental radiation monitoring system. Consequently in this paper, we proved that our gamma detector system is reliable for a gamma camera which can be used as small animal imaging and environmental radiation monitoring system.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.175-181
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• 2016

This paper introduces a heave compensation system for offshore crane when it gets unexpected disturbances and external force. The dynamic model consists of crane assumed to be the rigid body, hydraulic driven winch, elastic rope and payload. To keep the payload from moving up and down, PD control algorithm is applied. By using the control, the oscillating amplitude of the payload is reduced. Also by using the estimated values involved with time-delay, the relative motion of payload in heave direction is dramatically shortened. This paper shows using the control algorithm with estimated value having time-delay 0.1 second is enough to heave compensation system.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.205-215
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• 2002

In this paper the Dynamic Minislot Reservation Protocol(DMRP) in which the control channel is divided into contention-less and contention minislots in order to reduce re-transmission probability in multicasting is proposed. In the network, earth node has two pairs of transceivers. A transceiver consisting of a fixed transmitter and a fixed receiver is used to control packet registration and the other transceiver is used to transmit data. Two types f transceivers for data transmission are considered : one is FT-TR(Fixed Transmitter-Tunable Receiver) and the other is TT-TR(Tunable Transmitter-Tunable Receiver). In the analysis, FT-TR and TT-TR single-hop passive star networks are compared. As results, we conclude that the DMRP protocol with dynamically divided control channel has improved the system performance such as throughput and system delay regardless of traffic type or network structure.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.82-87
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• 2011

Heat transfer oils are used in applications such as heating systems of chemical plant, refinery heat exchange systems, gas plant process, injection molding systems, and pulp and paper processing. These oils are extremely stable and resistance to thermal and oxidative degradation. In the event of a spill or accidental release of heat transfer oils, it can be ignite easily when there is an ignition source. This paper discusses the flammability and thermal stabilities of new and used oils. The flammability of the oils are assessed by measuring changes in flash point and auto ignition temperature. The thermal stability of oils are evaluated by the thermal screening unit ($TS^u$) and the differential scanning calorimeter (DSC). From the experimental results, it is suggested to give fire hazard characteristics to safe precautions for the proper use and treatment of heat transfer oils.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.503-508
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• 2003

Since surgical treatment of the spine should overcome neurological compromises, the operative procedures need to be carefully planned and carried out with high degree of precision. Percutaneous vertebroplasty is a surgical procedure that was introduced for the treatment of compression fracture of the vertebrae. This procedure includes puncturing vertebrae and filling with polymethylmethacrylate (PMMA). Recent studies have shown that the procedure could provide structural reinforcement for the osteoporotic vertebrae while being minimally invasive and safe with immediate relief of pain. However, failures of treatment due to excessive PMMA volume injection have been reported as one of complications in vertebroplasty. It is believed that the control of PMMA volume is one of the most critical factors that can reduce the incidence of complications. Therefore, clinical success of vertebroplasty can be dependent on the volume of PMMA injection for a given patient. In this study, the optimal volume of PMMA injection for vertebroplasty was predicted based on the image analysis of a given patient.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.429-438
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• 2004

In this paper, a decision-feedback coherent code tracking loop is designed for WCDMA systems and its performance is analyzed in terms of jitter variance considering the effect of phase and symbol estimation errors for both AWGN and fading environments. An analytical closed-form formula for jitter variance is Int derived for AWGN environments as a function of a pulse-shaping filter, timing offset, signal-to-interference ratio, and loop bandwidth while involving the phase estimation error and bit error rate, and the upper bound of jitter variance is derived for fading environments. Finally a second-order coherent code tracking loop is designed with the DPCH frame format #13 of the WCDHA forward link selected as a target system, and its performance is evaluated by the closed-form formula and compared with the simulation results for both AWGN and Rayleigh fading environments.