• Journal of Digital Convergence
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• v.15 no.7
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• pp.375-382
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• 2017

Human resources required in society of knowledge and information are those who not only learn about knowledge and information but also apply those acquired sources to creatively trouble-shoot issues through independent or cooperative relationship. This study is to clarify that there is a positive effect from use of on-line game by youth as youth may have an opportunity to learn the competence required by present and future society of knowledge and information. Moreover, this study is to propose that positive competence may be acquired through on-line game and that the systematic device is required to show the classification of competence from game under characteristics of users. For upright settlement of gaming culture, game companies and the government are required to cooperate actively. Therefore, it is expected that the data from this study will be used as basis of studies of development of youth on-line game competence Quotient to grant upright gaming culture and youth on-line game competence Quotient.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.46.3-46.3
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• 2016

We present the ALMA Cycle 2 results "Two New SiO Maser Sources in High-Mass Star-Forming Regions" which was published in the Astrophysical Journal (Vol. 826, P157, 2016). Silicon monoxide (SiO) masers are rare in star forming regions, with the exception of five known SiO maser sources. However, we detected two new SiO maser sources from infrared loud clumps of the high-mass star forming regions G19.61-0.23 and G75.78+0.34 using the KVN single dish. High angular resolution observations with ALMA and JVLA toward G19.61-0.23 suggest that the deeply embedded young stellar object (YSO) of SMA 1 is powering the SiO masers. In addition, the SiO v=1, J=1-0 line shows four spike features while the v=2 maser shows combined features of one spike and broad wing components, implying energetic activities of the YSO of SMA 1 in the G19.61-0.23 hot molecular core. The SiO v=0, J=2-1 emission shows bipolar outflows in NE-SW direction with respect to the center of the SiO maser source. A high angular resolution map of the SiO v=1, J=2-1 maser in G75.78+0.34 shows that the SiO maser is associated with the CORE source at the earliest stage of high-mass star formation. Therefore, the newly detected SiO masers and their associated outflows will provide good probes for investigating this early high-mass star formation.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.39.3-39.3
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• 2017

To see scientific potential of MIRIS Paschen-${\alpha}$ ($Pa{\alpha}$) Galactic Plane Survey (MIPAPS), we have selected a portion, Galactic longitude from $+96^{\circ}$ to $116^{\circ}$, and inspected $Pa{\alpha}$ detections for 212 sources in WISE H II region catalog. We also list up $35Pa{\alpha}$ large features and $32Pa{\alpha}$ point-like blobs, which have not been cataloged in WISE catalog. For all the sources, we have performed the photometry of $Pa{\alpha}$ emission line, and obtained their $Pa{\alpha}$ intensities and $Pa{\alpha}$ fluxes. For the quantitative comparison, we also make the $H{\alpha}$ mosaic image of the same region by using IPHAS data which have been globally calibrated and released recently. Comparing MIPAPS $Pa{\alpha}$ fluxes with the IPHAS $H{\alpha}$ fluxes enables us to estimate dust extinction and spectral types of ionizing sources. We present the results for some sources.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.236.1-236.1
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• 2012

We conducted simultaneous 22GHz water maser and 44GHz class I methanol maser surveys of newly-identified 282 H2 emission features from the $2.122{\mu}m$ H2 narrowband image survey in the Galactic plane (UWISH2 project) using Korea VLBI Network (KVN) 21-m radio telescopes. We detected 16 and 13 new water and methanol maser sources, respectively. This result indicates that at least ~5% of the H2 emission features originate from young stellar objects (YSOs) that are in the right physical condition to produce the water and methanol masers. The masers are closely related to the current outflow activities in the Galactic plane. The power sources of these 23 diffused/collimated H2 emission features (six sources are detected for both masers) are likely to be intermediate-to high-mass YSOs, based on a comparison with the maser luminosities of other well-studied YSOs. Both maser velocities are mostly close to their own systemic velocities within 5 km/s, even though water masers generally show larger variabilities in the line intensities, velocities, and shapes than methanol masers. We also discovered three new water maser sources with high-velocity components: ~25 km/s red-shifted CMHO019, ~50 km/s blue-shifted CMHO132, and ~120 km/s blue-shifted CMHO182. In particular, we propose that the dominant blue-shifted water maser of CHMO182 could become a unique laboratory for the study of high-mass stellar jet and their accelerations.

• 전기의세계
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• v.18 no.6
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• pp.9-22
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• 1969

This thesis has suggested a method of applying the Maximum Principle of Pontryagin to the optimal control of distributive electrical networks. In general, electrical networks consist of branches, nodes, sources and loads. The effective values of steady state currents and voltages are independent of time but only expressed as the functions of position. Moreover, most of the node voltages and branch currents are not predetermined, that is, initially unknown, and their inherent loop characteristics satisfy only Kirchhoff's current and voltage laws. The Maximum Principle, however, needs the initial fixed values of all state variables for its standand way of application. In spite of this inconsistency this thesis has undertaken to suggest a new approach to the successful solution of the above mentioned networks by introducing scaling factors and a state variable change technique which transform the boundary-value unknown problem into the boundary-value partially fixed and partially free problem. For the examples of applying the method suggested, the control problems for minimizing copper quantity in a distribution line have been solved with voltage drop constraint imposed on. In the case of uniform load distribution it has been shown that the optimal wire diameter of the distribution line is reciprocally proportional to the root of distance. For the same load pattern as above the wire diameter giving the minimum copper loss in the distribution line has been shown to be reciprocally proportional to distance.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.75-80
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• 2012

In this paper a realistic bounding method for flooding analysis following rupture of large size of thanks and piping is defined. Mass and energy release during main feedwater line break accident is analyzed with RETRAN code. It is modeled that the main feed water control valve is closed in 5.0 seconds after reactor trip. In result of the analysis, largest mass and energy is discharged at 70% reactor power. The flood sources for main feedwater room are calculated when piping failure occurs in the high energy line and medium energy line. Based on the result of flood level (1.43m), it is investigated that all of the safety-related environmental qualification equipments are well located above the flood level.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1054-1062
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• 1991

In this paper a communication system using direct sequence spread spectrum (DS/SS) technique is constructed to transmit burst format data over power line channel with impulsive noise and narrowband interferences. Fast code synchronization is acquired by digital matched filter and data decision is accomplished by sampling pulses. In order to examine the performance of the power line communication system, but error rate and packet loss rate are measured over the simulation channel with various noise sources. When the packet composed of 1-bit preamble and 63-bit data is transmitted under very high burst impulsive noise, the bit error rate is about 10$^3$-10$^4$ and the packet loss rate is below 0.07.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.1
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• pp.1-10
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• 1989

The sensitivity analysis is a method to quantify to what extent the output of a model changes with the values of input parameters. This will lead to increase model accuracy through measurement validation. Three line source air quality models, HIWAY 2, PAL, and CALINE 3 were selected for this study. The input parameters analysed included wind speed, wind direction, stability, emission rate, mixing height, receptor distance, initial dispersion coefficient, surface roughness, and averaging time. It turned out that PAL model generally showed higher concentration than other two models, and that between CALINE 3 and HIWAY 2, CALINE 3 showed higher concentration than HIWAY 2 model near the line sources, but beyond a certain downwind distances HIWAY 2 model showed higher concentration. The modesl were very sensitive to wind speed especially in the range of 0 $\sim$ 1 m/s and to wind direction near the parallel wind to streets. In case of emission rate, the output concentration was directly proportional to these input parameters. And the sensitivity of the input parameters such as stability, mixing height, initial dispersion coefficient, surface roughness, and averaging time were not very significant.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1791-1795
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• 2007

Small ions generated at conductor corona sources remain in the atmosphere until they recombine with ions of opposite polarity, attach to aerosols, or make contact with an object. Ion current density is major factor to design conductor configuration of DC overhead transmission line. Several techniques have been used to measure the ion current of HVDC overhead transmission line. In this study, the ion current density was measured by a plate electrode made of a metal flat board at DC corona cage. The sensitivity of the plate electrode is $0.156uA/m^2/V$. To obtain an useful database on corona discharge, it is necessary to do corona test on several kinds of conductor bundles. Therefore, a number of experiments were conducted on several kinds of conductor bundles. To reliably analyze ion effects, corona cage test data were obtained over a long period of time under various weather conditions and expressed as a statistical distribution. Ion current density distribution in foul weather shows a significant increase in levels over the corresponding fair weather. Based on this results, we evaluated the environmental characteristic caused by ion flow of three candidated conductor bundles.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.5
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• pp.511-515
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• 2013

A Monte Carlo (MC) simulation study has been done in order to investigate the effects of line-edge-roughness (LER) induced by either 1P1E (single-patterning and single-etching) or 2P2E (double-patterning and double-etching) on fully-depleted silicon-on-insulator (FDSOI) tri-gate metal-oxide-semiconductor field-effect transistors (MOSFETs). Three parameters for characterizing the LER profile [i.e., root-mean square deviation (${\sigma}$), correlation length (${\zeta}$), and fractal dimension (D)] are extracted from the image-processed scanning electron microscopy (SEM) image for each photolithography method. It is experimentally verified that two parameters (i.e., ${\sigma}$ and D) are almost the same in each case, but the correlation length in the 2P2E case is longer than that in the 1P1E case. The 2P2E-LER-induced $V_TH$ variation in FDSOI tri-gate MOSFETs is smaller than the 1P1E-LER-induced $V_TH$ variation. The total random variation in $V_TH$, however, is very dependent on the other major random variation sources, such as random dopant fluctuation (RDF) and work-function variation (WFV).