• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.189-197
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• 2008

ENS-2 simulator is the most widely-used simulator in the research of wired/wireless communication. Since an IEEE 802.11 module has been implemented in NS-2. much research using this module has been done for various MAC layer functions. The most important problem in terms of performance is the hidden terminal problem. To solve this problem, the solutions using a busy-tone such as BTMA, DBTMA, etc. have been proposed. In order to be able to use a busy-tone, channels using the frequency bandwidth except the frequency bandwidth of the data channel is required for the collision prevention, and a MAC layer has to be able to menage such multiple channels. In this research, we implement a module that can use a busy-tone in NS-2, implement a modified RI-BTMA by applying the implemented module, and verify its performance.

• Progress in Medical Physics
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• v.27 no.1
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• pp.37-45
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• 2016

In proton therapy, in vivo proton beam range verification is very important to deliver conformal dose to the target volume and minimize unnecessary dose to normal tissue. For this purpose, a multi-slit prompt-gamma camera module made of 24 scintillation detectors and 24-channel signal processing system is under development. In the present study, we have developed and tested a dual-mode signal processing system, which can operate in the energy calibration mode and the fast data acquisition mode, to process the signals from the 24 scintillation detectors. As a result of performance test, using the energy calibration mode, we were able to perform energy calibration for the 24 scintillation detectors at the same time and determine the discrimination levels for the detector channels. Further, using the fast data acquisition mode, we were able to measure a prompt-gamma distribution induced by a 45 MeV proton beam. The measured prompt gamma distribution was found similar to the proton dose distribution at the distal fall-off region, and the estimated beam range was $17.13{\pm}0.76mm$, which is close to the proton beam range of 16.15 mm measured by an EBT film.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.31-38
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• 2009

To improve the image quality and lower the power consumption of the mobile applications, it is the one of the best candidate to control the backlight unit of the LCD module with ambient light. Ambient light sensor and readout circuit were integrated in LCD panel for the mobile applications, and we designed them with LTPS TFT. We proposed noble start-up correction in order to correct the variation of the photo sensors in each panel. We used time-to-digital method for converting photo current to digital data. To effectively merge time-to-digital method with start-up correction, we proposed noble dual slope correction method. The entire readout circuit was designed and estimated with LTPS TFT process. The readout circuit has very simple and stable structure and timing, so it is suitable for LTPS TFT process. The readout circuit can correct the variation of the photo sensors without an additional equipment, and it outputs the 4-levels digital data per decade for input luminance that has a dynamic range of 60dB. The readout rate is 100 times/sec, and the linearity error for digital conversion is less than 18%.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.927-930
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• 2003

In this paper, a design of processor IP for TCP/IP protocol stack is described. The processor consists of input and output buffer memory with dual bank structure, 32-bit RISC microprocessor core, DMA unit with on-the-fly checksum capability. To handle the various modes of TCP/IP protocol, hardware and software co-design approach is used rather than the conventional state machine based design. To eliminate delay time due to the data transfer and checksum operation, DAM module which can execute the checksum operation on-the-fly along with data transfer operation is adopted. By programming the on-chip code ROM of RISC processor differently. the designed stack processor can support the packet format conversion operations required in the various TCP/IP protocols.

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.2
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• pp.1-10
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• 2012

Clothing design is one of design products for human, the end user and corresponds to artifacts. Sometimes artifacts with one mono module exist, and so does artifacts assembled and combined with multi modules of same shape and size or various shapes and sizes and thus all design products can be understood by modularity concept. The purpose of this study was to make a new suggestion for the clothing design and production of high uniqueness and creativity by reviewing and synthesizing the foundation of clothing modularity concept as the original clothing design figures from the history have shown various modularity concept evolution from mono module to multi module stages. The methods of this study were to identify clothing modularity and analyze the type, evolving direction, and category of clothing modularity, and the value of clothing modularization design through comprehensive literature reviews on topic-related books and theses. The original clothing figures with Significance from the clothing history were analyzed in evolution sequence for application direction and value of clothing modularity in flat pattern. Clothing modularity in ancient clothing figures was classified as three types of the fixed, drapery, and straight lined in evolving direction from clothing of mono module to flat patterned clothing. The direction of clothing modularity was identified as mono- dual-triple-multi into another level of multi modularity after intentional devolution. The categorization of clothing modularity was identified in terms of clothing flat construction, clothing design construction, and clothing form modeling. The value of clothing modularization design using clothing modularity was identified as economical efficiency, convenience, promptitude, adaptability, functionality, and creativity.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.491-494
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• 2003

This paper presents a new conceptual electromagnetic induction eddy current-based stainless steel plate spiral type heater for heat exchanger or Dual Packs Heater in hot water producer, boiler steamer and super heated steamer, which is more suitable and acceptable for new generation consumer power applications. In addition, all active clamped edge resonant PWM high frequency inverter using trench gate IGBTs power module can operate under a principle oi zero voltage soft communication with PWM is developed and demonstrated for a high efficient Induction heated hot water producer and boiler in the consumer power applications. This consumer induction heater power appliance using active clamp soft switching PWM high frequency inverter is evaluated and discussed on the basis of the simulation and experimental results.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.207-209
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• 2019

This paper proposes a grid-tied photovoltaic (PV) system, consisting of Voltage-fed dual-active-bridge (DAB) dc-dc converter with single phase inverter. The proposed converter allows a small dc-link capacitor, so that system reliability can be improved by replacing electrolytic capacitors with film capacitors. The double line frequency free maximum power point tracking (MPPT) is also realized in the proposed converter by using Ripple Correlation method. First of all, to eliminate the double line frequency ripple which influence the reduction of DC source capacitance, control is developed. Then, a designing of Current control in DQ frame is analyzed and to fulfill the international harmonics standards such as IEEE 519 and P1547, $3^{rd}$ harmonic in the grid is directly compensated by the feedforward terms generated by the PR controller with the grid current in stationary frame to achieve desire Total Harmonic Distortion (THD). 5-kW PV converter and inverter module with a small dc-link film capacitor was built in the laboratory with the proposed control and MPPT algorithm. Experimental results are given to validate the converter performance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.67-73
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• 2013

The conversion of solar radiation into electrical energy by Photo-Voltaic (PV) effect is a very promising technology, being clean, silent and reliable, with very small maintenance costs and small ecological impact. The output power produced by the PV panels depends strongly on the incident light radiation. The continuous modification of the sun-earth relative position determines a continuously changing of incident radiation on a fixed PV panel. The point of maximum received energy is reached when the direction of solar radiation is perpendicular on the panel surface. Thus an increase of the output energy of a given PV panel can be obtained by mounting the panel on a solar tracking device that follows the sun trajectory. Tracking systems that have two axes and follow the sun closely at all times during the day are currently the most popular. This paper presents research conducted into the performance of Solar tracking system with photosensors. The results show that an optimized dual-axis tracking system with photosensor performance and analysis. From the obtained results, it is seen that the sun tracking system improves the energy and energy efficiency of the PV panel.ti-junction CPV module promises to accelerate growth in photovoltaic power generation.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.5
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• pp.249-254
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• 2013

In this paper we propose nonlinear control system for automatic unmanned vehicle using a RC (Radio Controlled) car which is usually controlled by a remote controller. In the proposed system, a RC car is dissembled and reassembled with several parts enabling it to be controlled by an android mobile platform with Bluetooth communication. In our system, an android mobile smartphone is mounted on the RC car and plays an important role as an eye of the car. The proposed system automatically controls the RC car to follow a lane that we draw on the floor of our laboratory. Also, the proposed RC car system can also be controlled manually using the accelerometer sensor of a smartphone through a Bluetooth module. Our proposed system that has both manual mode and automatic mode consists of several components; a microprocessor unit, a Bluetooth serial interface module, a smartphone, a dual motor controller and a RC toy car. We are now in the development of a group driving system in which one car follows the front car that tracks a lane automatically.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.9
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• pp.26-34
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• 1998

This paper presents a characterization method for faults of circuit patterns on MCM(Multichip Module) or PCB(Printed Circuit Board) substrates with electron beams of a SEM(Scanning Electron Microscope) by inducing voltage contrast on the signal line. The experimentation employes dual potential electron beams for the fault characterization of circuit patterns with a commercial SEM without modifying its structure. The testing procedure utilizes only one electron gun for the generation of dual potential electron beams by two different accelerating voltages, one for charging electron beam which introduces the yield of secondary electron $\delta$ < 1 and the other for reading beam which introduces $\delta$ > 1. Reading beam can read open's/short's of a specific net among many test nets, simultaneously discharging during the reading process for the next step, by removing its voltage contrast. The experimental results of testing the copper signal lines on glass-epoxy substrates showed that the state of open's/short's had generated the brightness contrast due to the voltage contrast on the surface of copper conductor line, when the net had charged with charging electron beams of 7KV accelerating voltages and then read with scanning reading electron beams of 2KV accelerating voltages in 10 seconds. The experimental results with Au pads of a IC die and Au plated Cu pads of BGA substrates provided the simple test method of circuit lines with 7KV charging electron beam and 2KV reading beam. Thus the characterization method showed that we can test open and short circuits of the net nondestructively by using dual potential electron beams with one SEM gun.