• Journal of the Korean Institute of Educational Facilities
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• v.23 no.1
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• pp.43-54
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• 2016

The purpose of this study was to survey teachers' perception of classroom space utilization through analyzing the physical environment of elementary school classrooms (56 classrooms in 10 schools). Most of the teachers arranged desks in the two person parallel type (sectional layout : standard type) for their classes. Although the number was small, some classrooms used the T type, H type, U type, group type, and the teachers of such cases used these layouts for children's play activities or group learning. Some teachers changed the desk layout depending on the contents of learning or for different atmosphere of class, but about 40% of the teachers used the same classroom layout without any change during a semester. When the teachers' perception of classroom space utilization was examined according to the type and change of desk layout, the quantity and characteristics of posts, the position of posting spaces, and the size of activity spaces in the classroom, most of the teachers tended to be conventional without any characteristic, and only 16% of them were relatively active in utilizing classroom spaces. In addition, teachers of a relatively small class were more active in utilizing classroom spaces. In particular, perception was very low to utilize the classroom as a space for children's life or play activities or various types of learning. These findings suggest that it is necessary to improve teachers' perception of classroom space utilization in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.536-542
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• 2011

For efficient utilization of spectrum resources in TV white space after DTV transition, FCC allowed usage of the spectrum for CR system. The CR system is required to cognize channel usage state for utilizing the unused spectrum in TV white space which coexists various primary and secondary systems. In the meantime, as a demand for high throughput communication had been increased recently, CR systems also consider to adopt channel bonding technology, thus spectrum sensing for channel bonded system is essentially required. In this paper, we propose a novel spectrum sensing algorithm for channel bonding system using a single channel receiver. For IEEE 802.l1af signal, the proposed algorithm provide detection probability of 90% with false alarm probability 10% at SNR -18dB for single channel system and at SNR -7dB for 8 channel bonded system, respectively. Utilizing the proposed scheme, we can detect channel bonded signal using only a single receiver, therefore system overhead for spectrum sensing can be reduced significantly.

• Journal of Astronomy and Space Sciences
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• v.33 no.2
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• pp.101-104
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• 2016

More than 100 γ−ray pulsars have been discovered by the Fermi Gamma-ray Space Telescope. With a significantly enlarged sample size, it is possible to compare the properties of different classes. Radio-quiet (RQ) γ−ray pulsars form a distinct population, and various studies have shown that the properties of the RQ population can be intrinsically different from those of radio-loud (RL) pulsars. Utilizing these differences, it is possible to further classify the pulsar-like unidentified γ−ray sources into sub-groups. In this study, we suggest the possibility of distinguishing RQ/RL pulsars by their spectral shape. We compute the probabilities of a pulsar to be RQ or RL for a given spectral curvature. This can provide a key to the estimation of the intrinsic fraction of radio-quietness in the γ−ray pulsar population, which can place a tight constraint on the emission geometry.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.168-175
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• 2002

The hydraulic acoustic attenuator fur an automotive active suspension system is so highly nonlinear and of high order that the analysis in time-domain has been performed quite little. In this paper, a state-space representation of the dynamics for a hydraulic attenuator was presented utilizing the electrical analogy. And the results of experiment were compared with those of simulation to validate the state-space model proposed. The comparison revealed that the state-space model proposed is practically applicable to estimate the dynamic responses of the hydraulic attenuator in time-domain.

• Korean Institute of Interior Design Journal
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• v.27 no.1
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• pp.39-47
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• 2018

This study is intended to suggest an improvement scheme of activating container multiplex cultural space through an analysis of container architecture characteristics and a survey of user satisfaction, focusing on container multiplex cultural space located in Seoul city. Hence, the elements of multiplex cultural space and the characteristics of container architecture were deduced and analyzed through precedent study and literature review relating to multiplex cultural space and container architecture, and then an analysis framework was established with items to measure the user satisfaction. Based on this, a questionnaire was created, and users were surveyed through on-site visit. The results of analyzing the container multiplex cultural space users' satisfaction are as follows. First, in order to increase user satisfaction, it is necessary to highlight visual element. Second, there is necessity for distinct space configuration, such as connection, stack and extension by utilizing the fixed specifications, the characteristics of container. Third, there is necessity for extended space where people feel a sense of openness. Fourth, it should be improved so that air is well circulated by installing glass, operable window, etc. In further research, it is thought necessary to make a study of commercial space and facilities inside university besides multiplex cultural space.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.253-257
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• 2008

In this paper, the performance of generic orthogonal space-time block codes (OSTBCs) introduced by Alamouti [2], Tarokh [3], and Su and Xia [11] is analyzed. We first define one-dimensional component symbol error function (ODSEF) from the exact expression of the pairwise error probability of an OSTBC. Utilizing the ODSEF and the bit error probability (BEP) expression for quadrature amplitude modulation (QAM) introduced by Cho and Yoon [9], the exact closed-form expressions for the BEP of linear OSTBCs with QAM in quasi-static Rayleigh fading channel are derived. We also derive the exact closed-form of the BEP for some OSTBCs which have at least one message symbol transmitted with unequal power via all transmit antennas.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.58.1-58.1
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• 2016

During the year 2016 the newly installed NYSC (National Youth Science Center) 1m optical telescope was officially commissioned. Calls for future observational programmes were announced. During test observations we carried out an observational project aimed at follow-up observations of transiting extrasolar planets. To predict future transits we developed the "TransitSearch" code implemented in Python utilizing transit information from the Open Exoplanet Catalogue. During three nights in April and June 2016 we observed planetary transits of HAT-P-3b and TrES-3b. Preliminary light curves of the transit events are presented alongside with best-fit models. From this experience we plan to improve the optical alignment and photometric performance by operating the 1m NYSC telescope in a strongly out-of-focus mode for transit observations.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.38.2-38.2
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• 2021

We, on behalf of Korean Gemini Office (KGO), present the comprehensive knowledge on the Gemini Band 3 program and introduce KGO's activities to promote research of Korean community utilizing Band 3 programs. We first describe the role and realities of Band 3 programs in comparison with Band 1 and 2. Then, we will provide useful suggestions for preparing Band 3 programs and introduce a few selected cases that successfully use the Band 3 time. In addition to Band 3, we will briefly summarize other proposal opportunities including the Fast Turnaround and Poor Weather Proposals.

• Journal of applied mathematics & informatics
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• v.42 no.2
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• pp.237-243
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• 2024

A similarity transformation of a solution of the Cauchy problem for the linear difference equation in Hilbert space has been studied. In this manuscript, we obtain necessary and sufficient conditions for linear equivalence of the discrete semigroup of operators, generated by the solution of the difference equation utilizing four Canonical semigroups.

• The Pure and Applied Mathematics
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• v.26 no.4
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• pp.289-303
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• 2019

We study the existence and uniqueness of fixed point for isotone mappings of any number of arguments under Mizoguchi-Takahashi contraction on a complete metric space endowed with a partial order. As an application of our result we study the existence and uniqueness of the solution to integral equation. The results we obtain generalize, extend and unify several very recent related results in the literature.