• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.427-431
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• 1994

The objective of this paper is to provide an inventory control policy for the system that carries a single item with a multiple demand classes, when the demand is Poisson distributed random variable. The inventory control process includes the process of determining the reorder point, and the process of inventory control during the lead time. The goal of the optimization process is to achieve the service level of each demand class as well as the system-wide total service level at a preset desired service level while sustaining a minimum average inventory.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.71-73
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• 2003

본 논문에서는 RF Matcher 의 동작성능 개선을 위하여 RF Match 제어단의 제어 알고리즘과 하드웨어의 디지털화 방안에 대한 연구를 수행하였다. 개발된 제어단은 최적의 동작성능을 위하여 multi-preset, 이득제어 기능 등 다양한 부가 기능을 갖도록 설계/제작하였고, 또한 LCD 모듈의 설치를 통하여 RF Matcher의 실시간 상태 파악이 가능하도록 하였다. 개발된 제어단에 대한 실험결과로부터 RF 전력의 over/under shoot, 플라즈마 플리커 등의 현상이 제거되었고, 정합시간이 크게 단축되었음을 알 수 있었다.

• Journal of IKEEE
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• v.18 no.3
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• pp.409-419
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• 2014

This paper proposes a new temperature control algorithm and system configuration of the pTMS(personal Thermal Massage System). By controlling the pulse width of the PWM(Pulse Width Modulation), the temparature of the heating lamp can be controlled stably, which is indispensable to the massage function. This technology is also adapted to the 'thermal massage', 'thermal acupressure', 'thermal moxibustion' functions of medical equipments. The temperature could be set at between $40^{\circ}C{\sim}70^{\circ}C$ by increments of $5^{\circ}C$, the control could be made in real time by increments of $1^{\circ}C$, and the temperature is displayed on the monitor by triggering every 2 seconds. when the present temperature is equal to the preset temperature, the PWM signal is minimized, and when the present temperature is higher than the preset temperature, overheating is prevented by interrupting the PWM output signal. When the difference of temperature exceeds $4^{\circ}C$, the PWM control is maximized in order for the system to reach the target temperature within a short period of time.

• Journal of Yeungnam Medical Science
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• v.5 no.1
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• pp.105-110
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• 1988

The study was undertaken to determine the most adequate tidal volume when used volume preset ventilator during anesthesia. The thirty patients were received controlled mechanical ventilation with constant inspiratory pressure of 10cmH2O and respiratory frequency of 12/minute. The results were as follows : 1) The PH was $7.39{\pm}0.01$ and it is within normal limit. 2) The $PaCO_2$ was $34.0{\pm}0.6$ mmHg and it is a slightly hyperventilatory state. 3) The $PaO_2$ was $228.0{\pm}8.2$ mmHg. 4) The Buffer base was $20.7{\pm}0.3mEql$ and it is a slightly buffer base deficient state. From the above results. We concluded that if patients were fully relaxed during general anesthesia, it is desirable to maintain the inspiratory pressure of anesthetic mechanical ventilator to $10cmH_2O$ for adeguate alveolar ventilation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.291-298
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• 2017

In this paper, we derive the achievable degrees of freedom (DoF) for multiple-input multiple-output (MIMO) Z-interference channels (Z-IC) with reconfigurable antennas at the receivers, assuming that channel state information is not available at the transmitters. We propose a new linear scheme to align interfering signals and to decode desired signals through the designed preset mode switching pattern of reconfigurable antennas at the receivers. The key idea of our scheme is to use interfering signals as a side information at the interfered receiver by being silent at the corresponding transmitter during some time slots. Consequently, it is shown that the reconfigurable antennas at the receivers can bring a DoF gain if the number of preset modes is greater than the number of RF chains at the receivers.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.7-13
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• 2017

Robot performances in public places are conducted for the purpose of promoting robot technology and inducing interest in events, exhibitions, and streets instead of dedicated stages. This paper extracts robot images in real time from a robot operation in front of a green chroma key cloth, and synthesizes them on various stage images. A simple and robust method for extracting a foreground robot from a chroma key background without a user's preset is proposed. After increasing the color difference between the background and the foreground, this method automatically removes the background based on the histogram of the difference information, thereby eliminating the need for a user's preset. The simulation shows 98.8% of foreground extraction rate and experimental results demonstrate that the robots can effectively be extracted from the background.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.185-192
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• 2001

In SRM drive, the ON·OFF angles of each phase switch should be accurately controlled in order to control the torque and speed stably. The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor, that are used to provide the information of the rotor position and to control the SRM power circuit, respectively. However, as the speed increases, the amount of the switching angle deviation from the preset values is also increased. Therefore, the low cost encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper, As a result, a stable high speed SRM drive can be achieved by the high resolution switching angle control and it is verified from the experiments that the proposed encoder the logic controller can be a powerful candidate for the practical low cost SRM drive.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1067-1070
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• 2002

The maximum demand power management system(the demand controller) is an equipment for demand management. If the pre-estimated load is over the preset power, the demand controller make warnings and break the load circuit according to predefined priority. Then consumption power is maintained below the maximum demand power level. The DTU receives the control commands from demand controller, and then controls loads. In this paper, the power line cables are used for communication between the demand controller and DTUs and monitoring PC. The experiments show that the proposed system is compatible with the conventional system, and feasible for new or remodeling plant.

• ETRI Journal
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• v.35 no.5
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• pp.757-766
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• 2013

This paper deals with the estimation of the time of arrival (TOA) of ultra-wideband signals under IEEE 802.15.4a channel models. The proposed approach is based on a randomness test and consists of determining whether an autoregressive (AR) process modeling an energy frame is random or not by using a distance to measure the randomness. The proposed method uses a threshold that is derived analytically according to a preset false alarm probability. To highlight the effectiveness of the developed approach, simulation setups as well as real data experiments are conducted to assess the performance of the new TOA estimation algorithm. Thereby, the proposed method is compared with the cell averaging constant false alarm rate technique, the threshold comparison algorithm, and the technique based on maximum energy selection with search back. The obtained results are promising, considering both simulations and collected real-life data.

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.2
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• pp.74-81
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• 2008

This paper describes a low-cost omnidirectional camera system designed for the intruder detection capability of a security robot. Moving targets on sequential images are detected first by an adaptive background subtraction technique, and the targets are identified as intruders if they fail to enter a password within a preset time. A warning message is then sent to the owner's mobile phone. The owner can check scene pictures posted by the system on the web. The system developed worked well in experiments including a situation when the indoor lighting was suddenly changed.