• Journal of Astronomy and Space Sciences
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• v.39 no.3
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• pp.117-126
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• 2022

The Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is one of the scientific instruments for the Compact Advanced Satellite 500-3 (CAS 500-3) which is planned to be launched by Korean Space Launch Vehicle in 2024. The main scientific objective of IAMMAP is to understand the complicated correlation between the equatorial electro-jet (EEJ) and the equatorial ionization anomaly (EIA) which play important roles in the dynamics of the ionospheric plasma in the dayside equator region. IAMMAP consists of an impedance probe (IP) for precise plasma measurement and magnetometers for EEJ current estimation. The designated sun-synchronous orbit along the quasi-meridional plane makes the instrument suitable for studying the EIA and EEJ. The newly-devised IP is expected to obtain the electron density of the ionosphere with unprecedented precision by measuring the upper-hybrid frequency (f_UHR) of the ionospheric plasma, which is not affected by the satellite geometry, the spacecraft potential, or contamination unlike conventional Langmuir probes. A set of temperature-tolerant precision fluxgate magnetometers, called Adaptive In-phase MAGnetometer, is employed also for studying the complicated current system in the ionosphere and magnetosphere, which is particularly related with the EEJ caused by the potential difference along the zonal direction.

• Journal of Powder Materials
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• v.20 no.4
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• pp.302-307
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• 2013

A5J32-T4 and A5052-H32 dissimilar aluminum alloy plates with thickness of 1.6 and 1.5 mm were welded by friction stir lap welding (FSLW). The FSLW were studied using different probe length tool and various welding conditions which is rotation speed of 1000, 1500 rpm and welding speed of 100 to 600 mm/min and material arrangement, respectively. The effects of plunge depth of tool and welding conditions on tensile properties and weld nugget formation. The results showed that three type nugget shapes such as hooking, void, sound have been observed with revolutionary pitch. This plunge depth and material arrangement were found to effect on the void and hooking formation, which in turn significantly influenced the mechanical properties. The maximum joint efficiency of the FSLWed plates was about 90% compared to base metal, A5052-H32 when the A5052-H32 was positioned upper plate and plunge depth was positioned at near interface between upper and lower plates.

• Proceedings of the Botanical Society of Korea Conference
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• 1985.08b
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• pp.73-81
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• 1985

We have previously isolated OsMADS4 gene that is a member of the class B MADS box genes from rice. In this study, another member of the class B MADS box genes was isolated from rice flower by the yeast two-hybrid screening method using OsMADS4 as bait. RNA blot analyses revealed that the clone, OsMADS16, was expressed in the second and third whorls, whereas the OsMADS4 transcripts were present in the second, third, and fourth whorls. These expression patterns of the OsMADS16 and OsMADS4 genes are very similar with those of AP3 and PI, the class B genes of Arabidopsis, respectively. In the yeast two-hybrid system, OsMADS4 interacted only with OsMADS16 among several rice MADS genes investigated, suggesting that OsMADS4 and OsMADS16 function as a heterodimer in specifying sepal and petal identities. We have also isolated OsMADS6 gene using OsMADS1 as a probe. Both are members of the AGL2 MADS family. Various MADS genes that encode for protein-protein interaction partners of the OsMADS6 protein were isolated by the yeast two-hybrid screening method. A majority of these genes belong to the AGL2 family. Sequence Homology, expression pattern, and ectopic expression phenotypes indicated that one of the interaction partners, OsMADS14, appears to be homologous to API, the class A MADS gene of Arabidopsis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.4
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• pp.73-79
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• 2015

Enhanced bandwidths of the GPS microstrip patch antennas applied by a Wilkinson power divider and a quadrature hybrid were compared. The square patch was designed, and fed by the two port probes for the circuit application. The Wilkinson power divider and quadrature hybrid circuit were designed, and applied to the patch antenna. The designed patch and two circuits were implemented on the FR4 board, and combined together. The measurement of the bandwidth within a voltage standing wave ratio (VSWR) of 2: 1 were 36.5% (1,200~1,775 MHz) in the case of the Wilkinson power divider and 29.84% (1,230~1,700 MHz) in the case of the quadrature hybrid. Axial ratios (AR) in 3dB were 17.14% bandwidth (1,360~1,630 MHz) and 15.87% bandwidth (1,400~1,650 MHz), respectively. The application of the Wilkinson power divider is wider than that of the quadrature hybrid. The peak gains in the anechoic chamber at the GPS center frequency were measured as 2.84 dBi and 2.75 dBi, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.630-638
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• 2005

As real-time media applications based on IP multicast networks spread widely, the end-to-end QoS (quality of service) provisioning for these applications have become very important. To guarantee the end-to-end QoS of multi-party media applications, it is essential to monitor the time-varying status of both network metrics (i.e., delay, jitter and loss) and system metrics (i.e., CPU and memory utilization). In this paper, targeting the multicast-enabled AG (Access Grid) group collaboration tool based on multi-Party real-time media services, a hybrid monitoring scheme that can monitor the status of both multicast network and node system is investigated. It combines active monitoring and passive monitoring approaches to measure multicast network. The active monitoring measures network-layer metrics (i.e., network condition) with probe packets while the passive monitoring checks application-layer metrics (i.e., user traffic condition by analyzing RTCP packets). In addition, it measures node system metrics from system API. By comparing these hybrid results, we attempt to pinpoint the causes of performance degradation and explore corresponding reactions to improve the end-to-end performance. The experimental results show that the proposed hybrid monitoring can provide useful information to coordinate the performance improvement of multi-party real-time media applications.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.173-184
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• 2018

As the portable traffic information collection system using probe vehicles spreads, it is becoming possible to collect road hazard information such as portholes, falling objects, and road surface freezing using in-vehicle sensors in addition to existing traffic information. In this study, we developed a integration and decision algorithm that integrates time and space in real time when multiple probe vehicles detect events such as road hazard information based on GPS coordinates. The core function of the algorithm is to determine whether the road hazard information generated at a specific point is the same point from the result of detecting multiple GPS probes with different GPS coordinates, Generating the data, (3) continuously determining whether the generated event data is valid, and (4) ending the event when the road hazard situation ends. For this purpose, the road risk information collected by the probe vehicle was processed in real time to achieve the conditional probability, and the validity of the event was verified by continuously updating the road risk information collected by the probe vehicle. It is considered that the developed hybrid processing algorithm can be applied to probe-based traffic information collection and event information processing such as C-ITS and autonomous driving car in the future.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.5 no.1
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• pp.43-59
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• 2006

A compact and broadband $4\times1$ array antenna was developed for 3G smart antenna system testbed. The $4\times1$ uniform linear away antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% $(VSWR\leq1.5)$, 21.78% $(VSWR\leq2)$ with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.7 no.1
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• pp.41-58
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• 2007

A compact and broadband $4{\times}1$ array antenna was developed for 3G smart antenna system testbed. The $4{\times}1$ uniform linear array antenna was designed to operate at 1.885 to 2.2GHz with a total bandwidth of 315MHz. The array elements were based on the novel broadband L-probe fed inverted hybrid E-H (LIEH) shaped microstrip patch, which offers 22% size reduction to the conventional rectangular microstrip patch antenna. For steering the antenna beam, a commercial variable attenuator (KAT1D04SA002), a variable phase shifter (KPH350SC00) with four units each, and the corporate 4-ways Wilkinson power divider which was fabricated in-house were integrated to form the beamforming feed network. The developed antenna has an impedance bandwidth of 17.32% ($VSWR{\leq}1.5$), 21.78% ($VSWR{\leq}2$) with respect to center frequency 2.02GHz and with an achievable gain of 11.9dBi. The design antenna offer a broadband, compact and mobile solution for a 3G smart antenna testbed to fully characterized the IMT-2000 radio specifications and system performances.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.560-570
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• 2005

In this paper, a microelectrode away DNA chip was fabricated on glass slide using photolithography technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5' end were immobilized on the gold electrodes by DNA arrayer utilizing the affinity between gold and sulfu. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Cyclic voltammetry in 5mA ferricyanide/ferrocyanide solution at 100 mV/s confirmed the immobilization of probe DNA on the gold electrodes. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 concentrated at the electrode surface through association with formed hybrid. It suggested that this DNA chip could recognize the sequence specific genes. It suggested that multichannel electrochemical DNA microarray is useful to develop a portable device for clinical gene diagnostic system.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.92.2-92.2
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• 2011

In view of the planned NASA's and ESA's Solar Probe Plus and Solar Orbiter missions, respectively, to probe the inner heliosphere and the Sun's corona, it is timely to investigate outstanding problems associated with the solar wind. Among them is the temperature anisotropy problem. As the solar wind expands into the interplanetary space, the density and magnetic field decreases radially, thus leading to temperature anisotropy ($T_{\parallel}{\gg}T_{\perp}$). However, the measured temperature anisotropy can at times be characterized by $T_{\perp}$ > $T_{\parallel}$, while at other times the measured $T_{\parallel}/T_{\perp}$ is much milder than predicted by adiabatic theory. Physical reasons remain poorly understood. This notwithstanding, it is known from plasma physics that for $T_{\perp}$ > $T_{\parallel}$ electromagnetic ion-cyclotron (EMIC) and mirror instabilities are excited, while for $T_{\parallel}$ > $T_{\perp}$, fire-hose instability is excited. By constructing the threshold conditions for various instabilities, one may construct a closure relation that may be useful for modeling the solar wind. In the present paper we discuss theoretical construction of the anisotropy-beta relation by means of quasi-linear theories of these instabilities. The present work complements previous efforts on the basis of linear theory, hybrid simulations, and empirical fits of observations.