• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.62.2-62.2
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• 2019

The ADF-S (AKARI Deep Field - South) toward South Ecliptic Pole is one of the deep survey fields designed for the study of Extragalactic Background Light (EBL). The deep extragalactic survey was initiated by AKARI far-infrared deep observations. Other space missions (e.g., Euclid, NISS, SPHEREx) will perform the deep observations in the ADF-S. Based upon the recent optical survey with KMTNet, we can identify the optical counterparts for dusty star-forming galaxies such as ULIRG, DOG, SMG. Among them, the Dust-Obscured Galaxies (hereafter DOGs with f(24um)/f(R) > 1,000) in the heavily obscured system are expected to play an important role in the formation of most massive galaxies. We have newly discovered ~100 DOGs in ~12 sq. deg. of the ADF-S from our optical survey with KMTNet. We also confirmed that some of DOGs host the most luminous AGN for their black hole masses through the near-infrared spectroscopic follow-ups. Here, we report the properties of high-z hyperluminous DOGs in the ADF-S.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.56.2-56.2
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• 2019

Measurement of the location of the baryon acoustic oscillation (BAO) feature in the clustering of galaxies has proven to be a robust and precise method to measure the expansion of the Universe. The best constraints so far have been provided from spectroscopic surveys because the errors on the redshift obtained from spectroscopy are minimal. This in turn means that the errors along the line-of-sight are reduced and so one can expect constraints on both angular diameter distance $D_A$ and expansion rate $H^{-1}$. But, future surveys will probe a larger part of the sky and go to deeper redshifts, which correspond to more number of galaxies. Analysing each galaxy using spectroscopy, which is a time consuming task, will not be practically possible. So, photometry will be the most convenient way to measure redshifts for future surveys such as LSST, Euclid, etc. The advantage of photometry is measuring the redshift of vast number of galaxies in a single exposure, but the disadvantage are the errors associated with the measured redshifts. Using a wedge approach, wherein the clustering is split into different wedges along the line-of-sight ${\pi}$ and across the line-of-sight ${\sigma}$, we show that the BAO information can be recovered even for photometric catalogues with errors along the line-of-sight. This means that we can get cosmological distance constraints even if we don't have spectroscopic information.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.31.4-32
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• 2018

The ADF-S (AKARI Deep Field - South) toward South Ecliptic Pole is one of the deep survey fields designed for the study of Cosmic Infrared Background (CIB). Owing to the easy accessibility with space missions and its low background brightness, the deep extragalactic survey was initiated by AKARI deep far-infrared observations and it will be performed by other future missions (e.g., Euclid, NISS, SPHEREx). The recent optical survey with KMTNet enabled us to identify the optical counterparts for dusty star-forming galaxies such as ULIRG, DOG, SMG. In addition, the NISS will perform the valuable spectro-photometric survey in the ADF-S. Those multi-wavelength data sets helps to trace the major galaxy population contributing to the CIB. Here, we introduce the extragalactic survey with the NISS and report the current status of the multi-wavelength extragalactic studies in the ADF-S.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.47.2-47.2
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• 2021

Focusing on both small separations and baryonic acoustic oscillation scales, the cosmic evolution of the clustering properties of peak, void, wall, and filament-type critical points is measured using two-point correlation functions in ΛCDM dark matter simulations as a function of their relative rarity. A qualitative comparison to the corresponding theory for Gaussian random fields allows us to understand the following observed features: (i) the appearance of an exclusion zone at small separation, whose size depends both on rarity and signature (i.e. the number of negative eigenvalues) of the critical points involved; (ii) the amplification of the baryonic acoustic oscillation bump with rarity and its reversal for cross-correlations involving negatively biased critical points; (iii) the orientation-dependent small-separation divergence of the cross-correlations of peaks and filaments (respectively voids and walls) that reflects the relative loci of such points in the filament's (respectively wall's) eigenframe. The (cross-) correlations involving the most non-linear critical points (peaks, voids) display significant variation with redshift, while those involving less non-linear critical points seem mostly insensitive to redshift evolution, which should prove advantageous to model. The ratios of distances to the maxima of the peak-to-wall and peak-to-void over that of the peak-to-filament cross-correlation are ~2-√~2 and ~3-√~3WJ, respectively, which could be interpreted as the cosmic crystal being on average close to a cubic lattice. The insensitivity to redshift evolution suggests that the absolute and relative clustering of critical points could become a topologically robust alternative to standard clustering techniques when analysing upcoming surveys such as Euclid or Large Synoptic Survey Telescope (LSST).

• Journal of Korea Technology Innovation Society
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• v.16 no.4
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• pp.937-953
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• 2013

The theoretical discussion of generation process and development directions of economic fluctuations are actively discussed. This study describes the economic changes applied to empirical research on economic volatility in Korea under the economic theory of network theory [Acemoglu, et al. 2012, 2010]. For the three years in 2000, 2005, and 2010, the network analysis were applied to industry input-output tables. The research results show that the network economic structures in Korea is shifted from a high connectivity among sectors to a lower connectivity. Also, the impact of key industries and the mutual connectivity of input and out among industrial sectors are weaken. Implications for industry and technology policy are derived form the study results.

• Journal of Educational Research in Mathematics
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• v.16 no.1
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• pp.1-23
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• 2006

It is regarded as critical to analyse and re-appreciate Euclidean geometry for the sake of improving school geometry This study, a critical analysis of demonstrative plane geometry in current secondary school mathematics with an eye to the viewpoints of 'Elements of Geometry', is conducted with this purpose in mind. Firstly, the 'Elements' is analysed in terms of its educational purpose, concrete contents and approaching method, with a review of the history of its teaching. Secondly, the 'Elemens de Geometrie' by Clairaut and the 'histo-genetic approach' in teaching geometry, mainly the one proposed by Branford, are analysed. Thirdly, the basic assumption, contents and structure of the current textbooks taught in secondary schools are analysed according to the hypothetical construction, ordering and grouping of theorems, presentations of proofs, statements of definitions and exercises. The change of the development of contents over time is also reviewed, with a focus on the proportional relations of geometric figures. Lastly, tile complementary way of integrating the two 'Elements' is explored.

• Journal of the Korean School Mathematics Society
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• v.10 no.3
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• pp.341-351
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• 2007

The primary purpose of this treatise is to suggest the solutions as follows for the errors concerning the triangle determination and congruence in every Korean mathematics textbook for 7th graders: showing that SsA, along with SSS, SAS, ASA, should also be included as the condition for triangle determination, congruence and similarity; proving that contrary to what has been believed, minimality applies only to congruence and similarity but not to determination; examining related Euclidean propositions; discussing the confusion about the characteristics of determination and congruence; and considering the negative effects of giving definite figures in construction education. The secondary purpose is to analyze the significance of triangle determinant that is not dealt with in either Euclid's Elements or the text books in the U.S. or Japan, and suggest a way to effectively deal with triangle determination and congruence in education.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.81-88
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• 2004

In this paper, we designed the outer encoder/decoder for the terrestrial DMB that is an advanced digital broadcasting standard, implemented, and verified by using ALTERA FPGA. In the encoder part, it was created the parity bytes (16 bytes) from the input packet (188by1e) of MPEG-2 TS and the encoded data was distributed output by the convolutional interleaver for Preventing burst errors. In the decoder part, It was proposed the algorithm that detects synchronous character suitable to DMB in transmitted data from the encoder. The circuit complexity in RS decoder was reduced by applying a modified Euclid's algorithm. This system has a capability to correct error of the maximum 8 bytes in a packet. After the outer encoder/decoder algorithm was verified by using C language, described in VHDL and implemented in the ALTERA FPGA chips.

• Journal of Educational Research in Mathematics
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• v.10 no.2
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• pp.263-277
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• 2000

mathematics holds a key position among the subject-matters of school education. Nevertheless, beyond Its Instrumental one, humanity-educational value of mathematics for the general public has been under estimated. For the past fifty years, in the our country there has not been enough systematic and profound examination and discussion concerning the goals of mathematics education in order to establish the philosophy of mathematics education. Thus, in this thesis we argue how mathematics education could contribute to the humanity education. For this, we examine how western educational theorists have emphasized the value of mathematics as humanity education and how their theories have been reflected in the goals of the modern mathematics education. First of all, we discuss Platonism as a philosophical basis of the traditional mathematics teaching mainly with Euclid's "Elements" since the ancient Greece and the relationship between mathematics education and humanity education in the light of this traditional thought. Next, we examine the thoughts of Pestalozzi, Harbert, Froebel who provided the theoretical basis for the public education since 19th century, and discuss the value of mathematics teaching in their humanistic educational thoughts. Also we examine the humanistic value of mathematics education in Dewey's educational philosophy, which criticized the traditional western ethics and epistemology, and established instrumen talism. Further, we analyze how such a philosophy of mathematics teaching is reflected mathematics education of 20th century, and confirm that the formation of Dewey's rational intelligence is one of the central aims of mathematics education of late 20th century. Finally, we discuss the ideals of humanistic mathematics education ; develop ment of the rational intelligence via 'doing knowledge'and change of mind via 'looking knowledge'. In this paper identify the humanistic values of mathematics education through the historical examination of the philosophies of mathematics education, and we could find significance as a fundamental study for one of the most important problems which Korean mathematics educational society confronts, that is establishing the philosophy of mathematics education.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1216-1224
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• 1988

In this paper, it is presented element generation, addition, multiplication and division algorithm over GF ($2^m$) to calculate multiple-valued logic function. The results of addition and multiplication among these algorithms are applied to the current mode CMOS circuits with ROM structure to design of adder and multiplier on GF ($2^m$). Table-lookup and Euclid's algorithm are required the computation in large quentities when multiple-valued logic functions are developed on GF ($2^m$). On the contrary the presented operation algorithms are prefered to the conventional methods since they are processed without relation to increasing degree m in the general purpose computer. Also, the presened logic circuits are suited for the circuit design of the symmetric multiplevalued truth-tables and they can be implemented addition and multiplication on GF ($2^m$) simultaueously.