• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.157-163
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• 2017

Due to economic development and advancement of medical science, an aging society where the proportion of the elderly population increases is coming. Korea's aging speed is growing rapidly compared to that of other developed countries. The physical and mental abilities of elderly people with aging are getting worse more and more. They want a kind of auxiliary system in order to mitigate and prevent their weakness. The supplementary system can greatly contribute to improving the quality of life for elderly people. In particular, some devices that include muscle strengthening and cognitive and balance ability enhancement are useful for the most older people. In this paper, we introduce a development of human care contents based rehabilitation equipment to enhance these functions, and present its usability evaluation. The evaluation is conducted for rehabilitation specialists as well as expected users and their results are analyzed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.5-12
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• 2000

As a semiconductor material for electronic devices operated under extreme environmental conditions, silicon carbides (SiCs) have been intensively studied because of their excellent electrical, thermal and other physical properties. The growth characteristics of single- crystalline 6H-SiC homoepitaxial layers grown by a thermal chemical vapor deposition (CVD) were investigated. Especially, the successful growth condition of 6H-SiC homoepitaxial layers using a SiC-uncoated graphite susceptor that utilized Mo-plates was obtained. The CVD growth was performed in an RF-induction heated atmospheric pressure chamber and carried out using off-oriented ($3.5^{\circ}$tilt) substrates from the (0001) basal plane in the <110> direction with the Si-face side of the wafer. In order to investigate the crystallinity of grown epilayers, Nomarski optical microscopy, transmittance spectra, Raman spectroscopy, XRD, Photoluninescence (PL) and transmission electron microscopy (TEM) were utilized. The best quality of 6H-SiC homoepitaxial layers was observed in conditions of growth temperature $1500^{\circ}C$ and C/Si flow ratio 2.0 of $C_3H_8$ 0.2 sccm & $SiH_4$ 0.3 sccm.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2955-2960
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• 2010

Spiro-type orange phosphorescent host materials, 9-diphenylphosphine oxide-spiro[fluorene-7,9'-benzofluorene] (OPH-1P) and 5-diphenylphosphine oxide-spiro[fluorene-7,9'-benzofluorene] (OPH-2P) were successfully prepared by a lithiation reaction followed by a phosphination reaction with diphenylphosphinic chloride. The EL characteristics of OPH-1P and OPH-2P as orange host materials doped with iridium(III) bis(2-phenylquinoline)acetylacetonate ($Ir(pq)_2acac$) were evaluated. The electroluminescence spectra of the ITO (150 nm)/DNTPD (60 nm)/NPB (30 nm)/OPH-1P or OPH-2P: $Ir(pq)_2acac$ (30 nm)/BCP (5 nm)/$Alq_3$ (20 nm)/LiF (1 nm)/Al (200 nm) devices show a narrow emission band with a full width at half maximum of 75 nm and $\lambda_{max}$ = 596 nm. The device obtained from OPH-1P doped with 3% $Ir(pq)_2acac$ showed an orange color purity of (0.580, 0.385) and an efficiency of (14 cd/A at 7.0 V). The ability of the OPH-P series to combine a high triple energy with a low operating voltage is attributed to the inductive effect of the P=O moieties and subsequent energy lowering of the LUMO, resulting in the enhancement of both the electron injection and transport in the device. The overall result is a device with an EQE > 8% at high brightness, but operating voltage of less than 6.4 V, as compared to the literature voltages of ~10 V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.86-93
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• 2010

This paper presents the guideline for enhancing the reliability and availability of SAS with IEC 61850 based IEDs in real power system. The IEC 61850 standard communication networks and systems allow utilities to consider new designs for substations applicable both new substation and refurbishments. The existing solutions are based on hardwired interface between the primary substation equipment and the secondary protection, monitoring, control and recording devices. All over the world, lots of projects at different stages of realization have been reported during the last year leading to a rapid maturation of the associated technologies. At present, IEC 61850 is becoming a popular communication standard for the substation automation system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.2
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• pp.135-140
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• 2011

Currently, studies have show that the network related energy consumption are increasing. and part of overall energy consumption of our society are too. So, that is important to look for energy-efficient network applications and protocols. A most of network energy consumption are due to network edge devices. in this paper, in order to cut down the emissions of carbon dioxide from ICT business, which contributes 2% of the global energy consumption, it is necessary to understand energy consumption in peer-to-peer system. In this paper, in this paper we propose a architecture based on the introduction of a p2p proxy. The model is analyzed analytically and numerically to reveal how these factors influence the overall power consumption in both steady state and flash crowd information exchange scenarios. Specifically, our results show that the proxy-based solution can provide up to 50% reduction in the energy consumption and, at the same time, a significant reduction in the average file download time.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.1-10
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• 2006

Ubiquitous computing, a new type of network environment has been generating much interest recently and has been actively studied. In ubiquitous computing, the sensor network which consists of low electric power ad-hoc network-based sensors and sensor nodes, is particularly the most important factor The sensor network serves as the mediator between ubiquitous computing and the actual environment. Related studies are focused on network . management through lightweight hardware using RFID. However, to apply these to actual environment, more practical scenarios as well as more secured studies equipped with secures and efficiency features are needed. Therefore, this study aims to build a wireless network based on PTD for multi users, which provides the largest utility in individual networks, and propose an appropriate management method. The proposed method is designed to enhance security and efficiency related to various services required in wireless networks, based on the reliable peripheral devices for users or pm. using pm, which has been applied to electronic commerce transactions in existing papers, this study also proposed an appropriate management method that is suitable for a dynamic environment and setting a temporary group to provide various services.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.401-406
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• 2015

Getter is a class of materials used in absorbing gases such as hydrogen and moisture in microelectronics or semiconductor devices to operate properly. In this study, we developed a new device structure consisting of porous anodized alumina films on textured silicon wafer, which have cost efficiency in materials and processing aspects. Anodic aluminum oxide (AAO) with controlled pore sizes can be applied to a high-efficiency moisture absorber due to the high surface area and OH- saturated surface property. The moisture sorption capacity was 2.02% (RH=35%), obtained by analyzing isothermal adsorption/desorption curve.

• Management & Information Systems Review
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• v.32 no.3
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• pp.247-261
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• 2013

Recently, the smart phone, a carrying along terminal connection technology such as Galaxytap/iPad etc. evolves, and supply is increasing rapidly, is included for smart phone because various sensor technologies are developed and service application that is acted in terminal with this is accompanied and grow. Continuously 4 generation to 3 Gs, Wibro Wireless network technology of communications a LTE technology from that is constructed, environment for Ubiquitous realization is being constructed fast. Therefore, in this paper it can inquire state of electronic, furniture devices through apartment complex web server and gear that control groove network at smart phone, and control, and confirms home state prevention of crimes state, and video inquiry of position that CCTV is placed in apartment complex was available. And it proposed integrated smart apartment with parking system and medical system using RFID system in ubiquitous environment.

• Journal of Convergence Society for SMB
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• v.6 no.3
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• pp.21-27
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• 2016

In this paper, we introduce the PB/MC-CDMA (Partial Block/Multi-Carrier-Code Division Multiple Access) system to mitigate inter-cell interference (ICI) and enhance user capacity in the small cell environment. In 5G mobile communications, the number of devices connected to the network is expected to increase exponentially with the expansion of the IoT (Internet of Things) services. In addition, each device is expected to be required by the various data rates by their content types. In LTE/LTE-A, there are some limitations that large scale connectivity and supporting various data rates. Therefore, we introduce a PB/MC-CDMA physical layer system which is suitable for the small cell environment, and evaluate the performance in the multi cell environment which is affected by ICI. Through computer simulation results, we demonstrate the effectiveness of PB/MC-CDMA for the small cell environment.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.249-253
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• 2009

This paper dealt with the insulation evaluation by a measurement of partial discharge(PD) on traction motors used in a hybrid vehicle. The PD method has been accepted as an effective and a non-destructive. technique to evaluate insulation performance of low-voltage electric and electronic devices. In this paper, the PD measurement system which was manufactured with a coupling network, a low noise amplifier, and an associated electronics is described. The PD measurement system has the frequency bandwidth of $1[MHz]{\sim}30[MHz]$ at -3 [dB] and the stable sensitivity of 19 [mV/pC] for the traction motor. From the experimental results, discharge inception voltage (DIV) and apparent charge (q) were $1,100[V_{rms}]$ and 105 [pC] for the used motor, and $1,400[V_{rms}]$ and 84 [pC] for the new one. By comparing the DIV and q, we could evaluate the insulation condition for the traction motors.