• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.22-24
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• 1996

Small size DC motor control method for portable drug delivery system has been developed to be used for the actuator of insulins pump. The control method gives the controllabilities both in high speed(40-50 revolution per second(rps)) DC motor drive and also in low speed(0.5-1rps). In low speed mode DC motor is controlled to act like stepping motor and in high speed to optimize power consumption. To control both mode modified bang bang control is suggested. Using this method small size DC motor(spec.) speed is controlled from 0.2 rps to 50 rps. Experimental setup is developed using micro-processor(PIC16C73, Micro Chips co., USA), motor turns checking circuitry, small size DC motor for pager(SM1012, Samhong co., Korea) and gear box. Results from experiment meet need for vailable load condition which is require for portable drug delivery system.

• Journal of Institute of Convergence Technology
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• v.2 no.1
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• pp.1-6
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• 2012

The cold chain system in South-East Asia is requiring to maintain freshness of refrigerated or frozen food. In this study, Thermal storage system using Phase change material (PCM) was developed and evaluated its performance about temperature and cold keeping time. For various application of cold chain system, we developed portable cold box, cold roll container and freezing station. Keeping time on laboratory tests of portable cold box in case of refrigeration and freezing were 6 hours and 4 hours, respectively. Cold container was developed to 2.5 ton scale. Evaluation in Indonesia, it was showed to keep the setting temperature of $-10^{\circ}C$ over 40 hours at $30^{\circ}C$ of ambient air. Freezing station using PCM was kept over 24 hours under $-20^{\circ}C$.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.83-90
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• 2018

Recently, many people have suffered from insomnia, labor loss, cognitive decline, and mental illness. The solution to this problem is almost entirely cognitive therapy or medication, but it is not recommended in the long term due to side effects and dependency problems. Therefore, in this paper, we propose a neuro feedback system based on portable EEG that helps induce sleeping. We design and evaluate the EEG classifier, which is the most important function to implement the system, and propose an optimized classifier modeling method for various factors that can affect performance. When using the proposed classifier, we could distinguish 97.9% of awakening and sleep phase in portable EEG.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1436-1442
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• 2015

In recently the world trend of security system for shipping transport is much more important and stronger, so following the world trend, there is development to security system of shipping transport for national security logistics system construction. it is still ongoing. For the world trend of security system, there is attempt of portable radiation detection, which is possible to get detection of nuclide in south Korea.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.23-27
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• 2008

This study is to evaluate the tool life of portable beveler which have various cooling system. It was compared with 3 different bevelers which has each other cooling system. Beveler A has no cooling system, beveler B has the cooling system for only inside of body, and beveler C has the cooling system for both the cutter and inside of body. The temperature of beveler A cutter surface had been continuously increasing as processing, but the rising tendency of temperature of beveler B cutter surface has slightly changed. In case of beveler C, the temperature is maintained. The tool life of beveler C is about 105m which is around 400% of beveler A(25m), and around 130% of beveler B(80m).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.678-681
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• 2003

In this paper, we aims to develop a microcontroll er-based portable pulse oximeter using Compact Flash Interface. First, portable pulse oxineter system is designed to record 2 channel of biosignals simultaneously, including 1 channel of SpO$_2$ and 1 channel of pulse rate. It is very small and portable. Besides, the system makes it possible to measure a patients condition without an additional medical equipment. We tried to solve the problems generated by a patient's motion. That is, we added an analog circuit to a traditional pulse oximeter in order to eliminate the change of the base line. And we used 2D sector algorithm. As present, SpO$_2$ modules are completed. But there are still many further development needed in order to enhance the function. Especially, compact flash interface remains the most to complete. Second, ECG monitoring system uses almost same as present 3-lead ECG system. But we focus on the analog part, especially in filter. The proposed filter is composed of two parts. One is a filter to remove the power-line interface. The other is a filter to remove the baseline drift. A filter to remove the power-line and the baseline drift is necessarily used in the ECG system. The implemented filter have three features; minimizing the distortion in DC component, removing the harmonic component of power-line frequency. Using compact flash interface, we can easily transfer a patient's personal information and the measured signal data to a network based server environment. That means, it is possible to implement a patient's monitoring system with low cost.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.41-45
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• 2016

The technology of supplying the electric power by wireless power transfer (WPT) is expected for the next generation power feeding system since it can supply the power to portable devices without any connectors through large air gap. As such a technology based on strongly coupled electromagnetic resonators is possible to deliver the large power and recharge them seamlessly; it has been considered as a noble option to wireless power charging system in the various power applications. Recently, various HTS wires have now been manufactured for demonstrations of transmission cables, motors, MAGLEV, and other electrical power components. However, since the HTS magnets have a lower index n value intrinsically, they are required to be charged from external power system through leads or internal power system. The portable area is limited as well as the cryogen system is bulkier. Thus, we proposed a novel design of wireless power charging system for superconducting HTS magnet (WPC4SM) based on resonance coupling method. As the novel system makes possible a wireless power charging using copper resonance coupled coils, it enables to portable charging conveniently in the superconducting applications. This paper presented the conceptual design and operating characteristics of WPC4SM using different shapes' copper resonance coil. The proposed system consists of four components; RF generator of 370 kHz, copper resonance coupling coils, impedance matching (IM) subsystem and HTS magnet including rectifier system.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.389-395
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• 2007

It is necessary to research on wireless position determination technology that enables location based services on Portable Internet. In this paper, I consider the position determination technology based on TDOA belong to trilateration method. That is using the difference of relative distance between base stations and terminal due to the time difference of arrival of downlink signal. In order to design the positioning server, This paper reviews the related research on current status of wireless position determination technology based on TDOA on Portable Internet. And then, it is suggested that system architecture, network interface, the calculation model for position determination, which are adapted to circumstance of portable Internet. Through this research on the positioning server, it is expected to guarantee that low cost and high efficiency of wireless positioning server on Portable Internet will be developed.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.455-459
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• 2013

The fuel processor for the portable fuel cell includes multi-step processes consisting of hydrogen generator, heat generator and several CO clean-up stages. One of requirements of the fuel processor for portable fuel cell system is a rapid start-up time. Especially, the warm-up time for WGS reactor is crucial factors for total start-up time. In this paper, active heating protocol, which is the heating protocol of WGS reactor supplied by the oxidation of CO rich reformate in the initial stage, is used for a rapid start-up. The air stream fed to the inlet of WGS reactor rapidly oxidize the CO rich reformate in the WGS reactor. Therefore, CO concentration in reformate quickly stabilized at the desired concentration without CO surges.

• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.113-120
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• 2013

Nowadays, the medical system towards patients changes into the medical services. As the human rights are improved and the capitalism is enlarged, the rights and needs of patients are gradually increasing. Also, based on this change, several systems in hospitals are revised according to the convenience and needs of patients. Thus, the cases of mobile portable among examinations are getting augmented. Because the number of mobile portable examinations in patient's room, intensive care unit, operating room and recovery room increases, neighboring patients are unnecessarily exposed to radiation so that the examination is legally regulated. Hospitals have to specify that "In case that the examination is taken out of the operating room, emergency room or intensive care units, the portable medical X-ray protective blocks should be set" in accordance with the standards of radiation protective facility in diagnostic radiological system. Some keep this regulation well, but mostly they do not keep. In this study, we shielded around the Collimator where the radiation is detected and then checked the change of dose regarding that of angles in portable tube and collimator before and after shielding. Moreover, we tried to figure out the effects of shielding on dose according to the distance change between patients' beds. As a result, the neighboring areas around the collimator are affected by the shielding. After shielding, the radiation is blocked 20% more than doing nothing. When doing the portable examination, the exposure doses are increased $0^{\circ}C$, $90^{\circ}C$ and $45^{\circ}C$ in order. At the time when the angle is set, the change of doses around the collimator decline after shielding. In addition, the exposure doses related to the distance of beds are less at 1m than 0.5m. In consideration of the shielding effects, putting the beds as far as possible is the best way to block the radiation, which is close to 100%. Next thing is shielding the collimator and its effect is about 20%, and it is more or less 10% by controlling the angles. When taking the portable examination, it is better to keep the patients and guardians far enough away to reduce the exposure doses. However, in case that the bed is fixed and the patient cannot move, it is suggested to shield around the collimator. Furthermore, $90^{\circ}C$ of collimator and tube is recommended. If it is not possible, the examination should be taken at $0^{\circ}C$ and $45^{\circ}C$ is better to be disallowed. The radiation-related workers should be aware of above results, and apply them to themselves in practice. Also, it is recommended to carry out researches and try hard to figure out the ways of reducing the exposure doses and shielding the radiation effectively.