• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.50-55
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• 2013

The smart grid is a next-generation power grid to create a new value-added information technology. Power providers and consumers exchange information in real-time bi-directional, and optimize energy efficiency with using the smart grid. This paper describes the concept of demand response of the communication system used in the protocol communication model of the smart grid.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.559-562
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• 2008

In this paper we propose a lock-in detection method for portable sensor systems and demonstrate with the portable detection module that has high sensitivity and robustness against the noise. The simple portable sensor module is manufactured using MCU(Micro Contorl Unit), OPAMP, MOSFET and a pair of infrared sensor. Manufactured sensor module is testified in the noisy environment caused by an external light and an white noise source. Without any type of band pass filters, we recover a signal of 33 $mV_{p-p}$ in 80 $mV_{p-p}$ white noise and get the DR(Dynamic Reserve) of 14 dB.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.583-588
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• 2008

A spacecraft propulsion system utilizing the energy of the solar wind was reviewed. The first plasma sail concept was proposed by Prof. Winglee in 2000, and that was called M2P2(mini-magnetospheric plasmapropulsion). However, the first M2P2 design adopting a small(20-cm-diamter) coil and a small helicon plasma source design was criticized by Dr. Khazanov in 2003. He insisted that: 1) MHD is not an appropriate approximation to describe the M2P2 design by Winglee, and with ion kinetic simulation, it was shown that the M2P2 design could provide only negligible thrust; 2) considerably larger sails(than that Winglee proposed) would be required to tap the energy of the solar wind. We started our plasma ssail study in 2003, and it is shown that moderately sized magnetic sails can produce sub-Newton-class thrust in the ion inertial scale(${\sim}70$ km). Currently, we are continuing our efforts to make a feasibly sized plasma sail(Magnetoplasma sail) by optimizing the magnetic field inflation process Winglee proposed.

• Biomolecules & Therapeutics
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• v.27 no.2
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• pp.145-151
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• 2019

Methamphetamine (METH) acts strongly on the nervous system and damages neurons and is known to cause neurodegenerative diseases such as Alzheimer's and Parkinson's. Flavonoids, polyphenolic compounds present in green tea, red wine and several fruits exhibit antioxidant properties that protect neurons from oxidative damage and promote neuronal survival. Especially, epicatechin (EC) is a powerful flavonoid with antibacterial, antiviral, antitumor and antimutagenic effects as well as antioxidant effects. We therefore investigated whether EC could prevent METH-induced neurotoxicity using HT22 hippocampal neuronal cells. EC reduced METH-induced cell death of HT22 cells. In addition, we observed that EC abrogated the activation of ERK, p38 and inhibited the expression of CHOP and DR4. EC also reduced METH-induced ROS accumulation and MMP. These results suggest that EC may protect HT22 hippocampal neurons against METH-induced cell death by reducing ER stress and mitochondrial damage.

• Development and Reproduction
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• v.23 no.2
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• pp.101-110
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• 2019

Melatonin is a pineal hormone that is synthesized and released at night under the light and dark cycles of a day. Its effects on the reproductive activities have well been established by the administration through various routes in photoperiodic animals. It was also identified in plants and named phytomelatonin. The capacity of the phytomelatonin was investigated in this investigation whether it affects the reproductive function in male golden hamster. As expected, animals housed in long photoperiod (long photoperiod, LP>12.5 hours of lights in a day) had large testes and animals kept in short photoperiod ($$SP{\leq_-}12.5$$ hours of lights in a day) showed remarkably reduced testes. The dietary supplement with melatonin itself induced the complete involution of testes. Pistachios that were reported to contain a large amount of melatonin demonstrated no effects at all in male golden hamsters. These results suggest that dietary supplement containing melatonin-rich foodstuff used in this investigation may not be enough to affect the reproductive endocrine system in male golden hamsters.

• Journal of Auto-vehicle Safety Association
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• v.15 no.4
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• pp.71-78
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• 2023

This study presents the direction of data triggers and elements to be recorded in automated vehicles in the future in relation to the event data recorder (EDR) and data storage system for automated driving (DSSAD). It does not distinguish between the EDR and DSSAD, but suggests data triggers and elements in preparation for overall automated vehicle accidents and dangerous situations. To propose, the current status of discussions on EDR/DSSAD internationally and the case of investigating accidents with automated vehicles under temporary driving licenses in Korea were analyzed. Based on the analysis, the direction of data triggers and elements of the EDR/DSSAD of automated vehicles were presented.

• Nonlinear Functional Analysis and Applications
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• v.29 no.2
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• pp.597-620
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• 2024

In this study, the conformable fractional derivative(CFD) of order 𝝔 in conjunction with the LC operator of orderρ is used to develop the model of the transmission of the A(H1N1) influenza infection. A brand-new A(H1N1) influenza infection model is presented, with a population split into four different compartments. Fixed point theorems were used to prove the existence of the solutions and uniqueness of this model. The basic reproduction number R₀ was determined. The least and most sensitive variables that could alter R₀ were then determined using normalized forward sensitivity indices. Through numerical simulations carried out with the aid of the Adams-Moulton approach, the study also investigated the effects of numerous biological characteristics on the system. The findings demonstrated that if 𝝔 < 1 and ρ < 1 under the CFD, also the findings demonstrated that if 𝝔 = 1 and ρ = 1 under the CFD, the A(H1N1) influenza infection will not vanish.

• Korean Journal of Digital Imaging in Medicine
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• v.9 no.2
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• pp.5-9
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• 2007

As developing the medical treatment image portion with the change of these times, PACS, which is able to digitalize image portion data, has a lot of data-based image data. Applying this PACS, we would like to settle down RNSXI(real-name shooting X -ray of inspector) system. We interviewed with P ACS's operators of university hospitals which is using PACS in Seoul about the present conditions whether using of RNSXI or not. And we inquired the RNSXI equipments, applying PACS database, and Interface conditions undertook to do in our hospital. All university hospitals in Seoul are set up the P ACS system. But no hospital use the RNSXI. In our hospital, we can check inspector' name or initials who exposure x-ray with the PACS Viewer by looking over equipments(CR, DR, US, MG, MR, CT) and Interface of the DICOM Header data. However, some equipments like RF and Angio can not check inspector' name or initials. Under the Film/System environment, RNSXI system has been used frequently like that inspector's signature or initial added to a patient data. Though the digital medical treatment was developed, RNSXI system was declined. It is necessary to using RNSXI system in order to improving radiologists' rights, even if it is not under the application of the medical treatment image laws. If RNSXI system use, radiologists should specialize in their major and the Repeat rate should be reduced. In environment of PACS, RNSXI system can be used by linking both the equipments and the Interface with a production enterprise of P ACS. Therefore RNSXI system applying the P ACS datebase should settle down in our medical system for being provided lots of data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.245-249
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• 2004

In this paper, we have proposed a clock recovery algorithm of Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio(OFDM/QPSK-DMR) system using Band Limited-Pulse Shaping Filter(BL-PSF) and compared the clock phase error variance of OFDM/QPSK-DMR system with that of single carrier DMR system. The OFDM/QPSK-DMR system using windowing method requires training sequence or Cyclic Prefix (CP) to synchronize the clock phase of received signal. But transmit efficient is increased in our proposed DMR system because of no using redundant data such as training sequence or CP. The proposed clock recovery algorithm is simply realized in the OFDM/QPSK-DMR system using BL-PSF. The simulation results confirm that the proposed clock recovery algorithm has the same clock phase error variance performance in a single carrier DR system under Additive White Gaussian Noise(AWGN) environment.

• Journal of Internet Computing and Services
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• v.2 no.3
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• pp.19-25
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• 2001

An educational system using computers was first conceptualized by Dr. Donald Bitzer in the University of Illinois in the late 1950s. Since the PLATO system was developed in 1961, multilateral research were made for the last 30 years. Especially, the development of Internet and Information Technology has contributed to the advancement of the distance education system. This system has greatly changed the existing educational paradigm, As the result, new education system is being realized, This study suggests a distance education system based on ‘push’ technique, which is a means of active information transmission, In this system, the ‘push’ technique is combined with the existing distance education system. Through the combination, learning contents can be provided for learners without connecting the DB on the Internet. In addition, the process of getting new information is real-timed operation. Also, the treatment of item; and the algorithm of level-based item evaluation are devised in consideration of various levels of learners, so that evaluation of items appropriate to the levels of learners can be accomplished.