• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.592-602
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• 2014

In the Integrated Gasification Combined Cycle (IGCC), the stability of the gasifier has strong influences on the rest of the plant as it supplies the feed to the rest of the power generation system. In order to ensure a safe and stable operation of the entrained-flow gasifier and for protection of the gasifier wall from the high internal temperature, the solid slag layer thickness should be regulated tightly but its control is hampered by the lack of on-line measurement for it. In this study, a previously published dynamic simulation model of a Shell-type gasifier is reproduced and two different linear model predictive control strategies are simulated and compared for multivariable control of the entrained-flow gasifier. The first approach is to control a measured secondary variable as a surrogate to the unmeasured slag thickness. The control results of this approach depended strongly on the unmeasured disturbance type. In other words, the slag thickness could not be controlled tightly for a certain type of unmeasured disturbance. The second approach is to estimate the unmeasured slag thickness through the Kalman filter and to use the estimate to predict and control the slag thickness directly. Using the second approach, the slag thickness could be controlled well regardless of the type of unmeasured disturbances.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.1
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• pp.47-55
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• 2005

This work describes an 8b 240 MS/s CMOS ADC as one of embedded core cells for high-performance displays requiring low power and small size at high speed. The proposed ADC uses externally connected pins only for analog inputs, digital outputs, and supplies. The ADC employs (1) a two-step pipelined architecture to optimize power and chip size at the target sampling frequency of 240 MHz, (2) advanced bootstrapping techniques to achieve high signal bandwidth in the input SHA, and (3) RC filter-based on-chip I/V references to improve noise performance with a power-off function added for portable applications. The prototype ADC is implemented in a 0.18 um CMOS and simultaneously integrated in a DVD system with dual-mode inputs. The measured DNL and INL are within 0.49 LSB and 0.69 LSB, respectively. The prototype ADC shows the SFDR of 53 dB for a 10 MHz input sinewave at 240 MS/s while maintaining the SNDR exceeding 38 dB and the SFDR exceeding 50 dB for input frequencies up to the Nyquist frequency at 240 MS/s. The ADC consumes, 104 mW at 240 MS/s and the active die area is 1.36 ㎟.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.27-34
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• 2010

In a test duct with closed configuration, particle removal performance of an edge-plate type electrostatic precipitator (ESP) was evaluated at a high flow rate in $CO_2$ rich environments by changing gap distances between collection plates, concentrations of $CO_2$, particle sizes, types of electrodes, and types of power supplies. At the same experimental conditions, collection efficiency of particles with the mean particle size, 300 nm, decreased as the gap distance and $CO_2$ concentration increased because of low electrostatic force and low discharged current. In addition, as the particle size increased, the efficiency increased because of high charging rate of the large particles. With the electrode type which has higher surface area of a discharging plate and with the power supply which applied 25 kHz-pulsed DC voltages, the removal efficiency was high even in rich $CO_2$ condition due to high electrostatic force at the same power consumption.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.93-102
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• 2018

This paper reports a Surge Protective Device (SPD) that is used to protect an automatic metering interface (AMI) power supplies of communication equipment on a low-voltage distribution system from a lightning current. The surge protective device (SPD) can be classified as one-port SPDs and two-port SPDs with decoupling elements depending on the connection type. The protection of internal systems against the lightning current may require a systematic approach consisting of coordinated SPDs. To deal with this, the definition of a lightning protection zone (LPZ) was studied and interpreted through a theoretical review. Because the lightning current resulting from a lightning surge is considerably high, there is limited protection from one SPD; therefore, coordinated cascaded MOV-based SPDs are installed to solve this problem. Regarding the power grid mentioned in this paper, a class II SPD for the low-voltage distribution system installed on the border of LPZ1 and LPZ2, which establish a protection coordination with the Arrester (LA, SA) that corresponds to the LPZO installed on the MOF stage connected to one system were designed to protect various communication (control) equipment, including the automatic meter reading system inside the branch-type electric supply panel of a building, not the incoming side of one system. In addition, performance-related tests were done by a comparison with the existing method through testing, and the optimal design was achieved for the 1-port SPD that uses a series connection and can bleed load current without any decoupling element.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.581-584
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• 2009

Recently, the cameras which used for observation are installed in children protection area and local crime prevention area in order to protect life and property and by its work being recognized and are installed more. Normal cameras have cost problem to observe multiple area and detail, because they can observe only one place. PTZ camera can observe multiple area by moving focus by schedule or remote control, but it can't automatically move the focus of it to the place where event occurred, because it can't recognize the place. In this study, we can monitor multiple area effectively, by installing a wireless sensor node equipped with temperature, lighting, gas and human detection sensor to each area, to monitor many place low-price and actively and to move the focus of PTZ camera to preset position, and send recorded video to the user, when the various sensor data received from wireless sensors in observation area are to be determined abnormal by analyzing. In addition, at night we can record a scene using infrared, but to reduce power consumption of lighting system which are installed to improve resolution, it supplies power to the lighting system when event occurred. So we were able to implement low power green monitoring system.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.103-113
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• 2014

Bargain position and trust are core issues in supply chain management, yet the effect of bargain position on trust remains to be undetermined. The purpose of this research is to present theoretical and methodological hurdles for the relationship among various bargain positions and trust, and develops a set of hypotheses about the asymmetric effect of bargain position on trust in supply chain network. An analytical tool to analyze nonlinear effects on a response surface is introduced. Based on the data collected through a survey of firms participating in Project Supply chain, a set of hypotheses is tested. The analysis results support the prediction that the bargain position perceived by the buyers have asymmetric effects on trust toward supplies, and provide more fine-grained accounts on the relationships among bargain power, bargain position and trust in a supply chain network.

• Journal of Korea Multimedia Society
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• v.18 no.5
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• pp.652-662
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• 2015

It is necessary to develop small, implantable bio-telemetry systems which can measure and transmit patients' bio-signals from internal body to external receiver. When measuring bio-signals, like electrical bio-signals, acoustic bio-signal measurement has also a big clinical usefulness. But, sound signal has larger frequency bandwidth than any other bio-signals. When considering these issues, a wireless telemetry system which has rapid data transmission rate proportional to wide frequency bandwidth is necessary to be developed. The bluetooth module is used to overcome the data rate limitation caused by the large frequency bandwidth. In this paper, a novel multimedia bluetooth biotelemetry system was developed which consists of transmitter module located in the body and receiver device located outside of the body. The transmitter consists of microphone, bluetooth, and wireless charging device. And the receiver consists of bluetooth and codec system. The sound inside the skin is captured by microphone and sent to receiver by bluetooth while charging. The wireless charging system constantly supplies the electric power to the system. To verify the performance of the developed system, an in vitro experiment has been performed. The results show that the proposed biotelemetry system has ability to acquire the sound signals under the skin.

• Fashion & Textile Research Journal
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• v.19 no.2
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• pp.221-229
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• 2017

This study researched the needs of smart fashion items using energy harvesting for outdoor wearers and surveyed the application areas and design preferences for energy-harvesting systems based on outdoor activities. A total of 217 subjects were surveyed. Subjects who had at least 3 years of experience in outdoor activities were selected in order to increase the reliability of the research results. The survey investigated lifestyles based on outdoor activities, outdoor clothing and electronic equipment usage, purchase style, utilization plan, and design preference for energy-harvesting clothing and supplies. The results showed that 62.7% of the respondents had experience in outdoor activities for more than five years. 96.3% of the subjects carried electronic equipment, and 179 participants(82.5%) experienced discomfort due to battery consumption/dead batteries during outdoor activities. 78.4% were interested in smat fashion items using energy-harvesting technology, and the energy-conversion technology that was useful for outdoor activities was "kinetic energy"(74.7%). Participants showed a high preference for a detachable type(30.9%) and a city type(69.1%) that can be worn in outdoor activities as well as in general life. The preferred location of the electric power-charging device was the "Hem area of top garment"(35.9%), and the reason for this selection was that it was easy to operate and did not interfere with movement. The data from this paper can be used as a basis for product planning and product design for energy-harvesting apparel designers and supply developers for outdoor clothing.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.25-31
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• 2017

This paper presents a 270/540/750/1500-Mb/s serial-data transmitter realized in a $0.13-{\mu}m$ CMOS technology for the applications of video data transmission. A low-cost RG-58 copper cable(5C-HFBT-RG6T) is exploited as a transmission medium connected to a single BNC connector, which shows cable loss 45 dB in maximum at 1.5 GHz. RLGC modeling provides an equivalent circuit for SPICE simulations of which characteristics are very similar to the measured cable loss. The loss can be compensated by pre-emphasis at transmitter and equalization at receiver if needed. Measurements of the proposed transmitter chip demonstrate the operations of 270-Mb/s, 540-Mb/s, 750-Mb/s and 1.5-Gb/s, and provide the output voltage levels of $370mV_{pp}$ at 1.5 Gb/s even with the pre-emphasis turned-off. The total power consumption is 104 mW from 1.2/3.3-V supplies and the chip occupies the area of $1.65{\times}0.9mm^2$.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.4
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• pp.277-285
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• 2001

We developed a compact, 10 kWe, purifier-integrated reformer which supplies hydrogen for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by palladium alloy membrane and catalytic combustion by noble metal coated wire-mesh catalyst were combined with the conventional methanol steam reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems. In this system, steam reforming, hydrogen purification, and catalytic combustion take place all in a single reactor so that the whole system is compact and easy to operate. The module produces $8.2Nm^3/hr$ of 99.999% or higher purity hydrogen with CO impurity less than 10 ppm, which is equivalent to 10 kWe when PEMFC has 45 % efficiency. Thermal efficiency of the module is 81 % and the power density of the module is 1.6 L/kWe. As the results of experiments, cold-start time has been measured about 20 minutes. Response time of hydrogen production to the change of the feed rate has been within 1 minutes.