• Education of Primary School Mathematics
• /
• v.12 no.1
• /
• pp.21-30
• /
• 2009

National university of education here in Korea have had a special purpose training competent primary school teacher hoping our nation and society so far. We can guess how students are educated and which direction focuses on education in college or university if we see the curriculum of the university. But the content of mathematics curriculum which is currently operated in ten university of education is a little different according to the major subject (pure mathematics, subject matters and so on)of the faculty or situation of the university. The purpose of this study is to get some suggestive points for the development of mathematics program and lecture assessment system which are appropriate training primary school teacher of future oriented as a special purpose university with looking around of lecture assessment system as well as comparing and looking around of the curriculum which are establishing at the auckland college of education there in the New Zealand and mathematics education department here in Daegu national university of education.

• School Mathematics
• /
• v.6 no.4
• /
• pp.345-359
• /
• 2004

Many researchers have studied students' error patterns in learning mathematics but the results haven't much effected on teaching situation. This paper is to find out how the results have been reflected on 6th and 7th Korean elementary school mathematics textbooks, workbooks, and teachers' guide books. The focuses of analysis are the four; (a)Type of materials, (b)Type of problems, (c)Type of errors and number of rela- ted problems, and (d)organization and explanation type. Results indicate that both 6th and 7th materials don't use effectively students' error patterns to teach computation, in particular, 7th textbooks scarcely treat them. It suggests that we should grope a way to use the fruitful results of this area to teach mathematics effectively.

• Journal of Science of Art and Design
• /
• v.3
• /
• pp.62-86
• /
• 2001

This study is based on theoretical background about movements of visual communication highlighted in digital age. Such movements are variously expressed in animation with the advancement of media, and their expression has great effect on visual art. Artists' concern and endeavor about movement expression techniques have been continued by impressionism, expressionism, futurism, cubism closely related with the birth of movie from late 19th century to early 20th century. At that time, stationary 2D space in plane screen couldn't express movement or time directly. Later, artists and designers have attempted to approach illusions in pictures or 4 dimension and movements by 2D or 3D computer graphics. The visual image in present digital age is to see, to hear, to feel by timing, so it is necessary for the most efficient way of message communication. And then, it is the time to start new, scientific, and creative study about production techniques of animation and expression of movements, since domestic animation productions are rapidly changed from cell to digital. The aim of this study is to clarify the motive of movement by theoretical inquiry of animation. Various aspects of animation as synthetic art have been examined by mathematical, scientific, and philosophical viewpoint. The results will be useful to the expression of motions for maximization of emotional effect in animation production or basic data of virtual simulation about certain situation. Therefore, such study should be managed as multidisciplinary research in the rapidly changing visual culture paradigm. namely, animation includes much more imaginative & creative power than simple function or techniques, so it has to be recognized as special synthetic art(visual art) constructing an area, the formative art with philosophical viewpoint and scientific principles.

• The Korean Journal of Applied Statistics
• /
• v.33 no.4
• /
• pp.421-437
• /
• 2020

This paper implemented a method to predict the fertility rate, mortality rate, and international migration rate using the R program, which has been widely used in recent years, that calculates population projection by substituting the results into the Leslie matrix. In particular, the generalization log gamma model for the fertility rate by Kaneko (2003), LC-ER model for mortality rate by Li et al. (2013), and functional data model for international migration rates proposed by Ramsay and Silverman (2005) and Hyndman and Booth (2008), Hyndman et al. (2013) can be directly demonstrated with R programs. Demography and bayesPop have been introduced as a representative demographic package implemented in R; however, it can be analyzed only for data uploaded to Human Mortality Database (HMD) and Human Fertility Database (HFD) with data changes and modifications requiring application of other data. In particular, in Korea, there is a limitation in applying this package because it is provided only for short-term data in HMD. This paper introduces an R program that can reflect this situation and the different patterns of low fertility, aging, migration of domestic and foreigners in Korea, and derives a population projection for the year 2117.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.31 no.5
• /
• pp.86-94
• /
• 1999

Alkaline peroxide bleaching of chemi-mechanical pulp is a very complicated system where various process factors affect the bleacing performance and pulp properties. Traditional onefactor-at a time method is ineffective and costly infinding the optimal bleaching conditions. In this study, statistical experimental design and multiple regression method wre used to investigated the interactions among various bleaching factors and to find out the possbile maximal brightness development during one stage alkaline peroxide bleacing of TMP. The TMP was made from 10% Korean red pine and 90% Korean spruce and had an initial brightness of 54.5% ISO. the TMP was pretreated with EDTA(0.5% on O.D. pulp, 3% pulp consistency, 30$^{\circ}C$ for 60 minutes) and bleached in a 2 L Mark V Quantum Reactor at 750 rmp, 7.5% of bleaching consistency and with 0.05% magnesium sulfate addition. The ranges of chemical factors studied , based on oven-ried pulp, were 1-5% for hydrogen peroxide, 1-4% for sodium hydroxide and 1-4% for sodium silicate. The rages of reaction temperature and time were 50-90$^{\circ}C$ and 40-180minutes respectively. Interactions of hydrogen peroxide with alkali , time with temperature ature, alkali with time and silicate with temperature were found to be significant which means that hydrogen peroxide bleaching will be favored at stable concentration of perhydroxyl ion, relatively short time and low temperature, and high level of silicate. Mathematical model which has good predictability for target brightness in one stage peroxide bleaching can also be established easily. Base ion the model, maximal brightness of 70% ISO was found to at 50$^{\circ}C$ and 50 minutes by chemical additions of 5% for hydrogen peroxide, 3.2-3.4% for sodium hydroxide and 4% for silicate based on O.D. pulp. However, this result might not be suitable for situation where furnishes are different from ours, or different pretreatment is used, or bleaching carried out at different pulp consistency. In these cases it will be good to re-investigate the process by a similar methodology as was used in this study.

• Journal of Korea Multimedia Society
• /
• v.23 no.6
• /
• pp.772-783
• /
• 2020

Tsunami is a frightful natural disaster that causes severe damages worldwide. To minimize the damage, South Korea has built a tsunami warning system and designated evacuation sites in the east and south coasts. However, such countermeasures have not been verified whether they are adequate to minimize casualties since tsunami rarely occurs in South Korea. Recently, due to increasing earthquakes in the west coast of Japan, the likelihood of South Korea entering the damage area of tsunami rises; thus, in this paper, we develops a simulator based on Unity game engine to simulate the evacuation from tsunami. In order to increase the fidelity of the simulation results, the simulator applies a tsunami simulation model that analyzes coastal inundation based on cellular automata. In addition, the objects included in tsunami evacuation, such as humans, are modeled as an agent model that determines the situation and acts itself, based on the discrete-event system specification (DEVS), a mathematical formalism for describing a discrete event system. The tsunami simulation model and agent models are integrated and visualized in the simulator using Unity game engine. As an example of the use of this simulator, we verify the existing tsunami evacuation site in Gwangalli Beach in Busan and suggest the optimal alternative site minimizing casualties.

• Journal of Engineering Education Research
• /
• v.1 no.1
• /
• pp.80-85
• /
• 1998

Yak-yong Jung discussed technology for the first time in Korea, 195 years ago, in his [Ki-ye-lon](the Theory of Techne: 1802) in which he investigated the essence and the developmental aspect of technology and the ways to promote technology. As a man of the 19th century when the West was being transformed into an industrial society by the Industrial Revolution, Jung suggested various ways to reform his nation an agricultural society. Although they were not accepted by the Dynasty, consideration of the social and economic situation and the world history at that time shows that they were very innovative. This study aims at defining Jung's view of technology, centering around [Ki-ye-lon](the Theory of Techne), and discusses what the technological education should emphasize in the future, that is to say: mathematical and scientific principles, the utility of technology, its developmental aspect, technological policy.

• Structural Engineering and Mechanics
• /
• v.9 no.3
• /
• pp.241-256
• /
• 2000

The major sources of energy dissipation in steel frames with partially restrained (PR) connections are evaluated. Available experimental results are used to verify the mathematical model used in this study. The verified model is then used to quantify the energy dissipation in PR connections due to hysteretic behavior, due to viscous damping and at plastic hinges if they are formed. Observations are made for two load conditions: a sinusoidal load applied at the top of the frame, and a sinusoidal ground acceleration applied at the base of the frame representing a seismic loading condition. This analytical study confirms the general behavior, observed during experimental investigations, that PR connections reduce the overall stiffness of frames, but add a major source of energy dissipation. As the connections become stiffer, the contribution of PR connections in dissipating energy becomes less significant. A connection with a T ratio (representing its stiffness) of at least 0.9 should not be considered as fully restrained as is commonly assumed, since the energy dissipation characteristics are different. The flexibility of PR connections alters the fundamental frequency of the frame. Depending on the situation, it may bring the frame closer to or further from the resonance condition. If the frame approaches the resonance condition, the effect of damping is expected to be very important. However, if the frame moves away from the resonance condition, the energy dissipation at the PR connections is expected to be significant with an increase in the deformation of the frame, particularly for low damping values. For low damping values, the dissipation of energy at plastic hinges is comparable to that due to viscous damping, and increases as the frame approaches failure. For the range of parameters considered in this study, the energy dissipations at the PR connections and at the plastic hinges are of the same order of magnitude. The study quantitatively confirms the general observations made in experimental investigations for steel frames with PR connections; however, proper consideration of the stiffness of PR connections and other dynamic properties is essential in predicting the dynamic behavior.

• Proceedings of the KSPS conference
• /
• 1996.10a
• /
• pp.274-274
• /
• 1996

This presents the preliminary results from work in progress of a paired study of the acquisition of voiceless stops by Spanish speakers learning English, and American English speakers learning Spanish. For this study the hypothesis was that the American speakers would have no difficulty suppressing the aspiration in Spanish unaspirated stops; the Spanish speakers would have difficulty acquiring the aspiration necessary for English voiceless stops, according to Eckman's Markedness Differential Hypothesis. The null hypothesis was proved. All subjects were given the same set of disyllabic real words of English and Spanish in carrier phrases. The tokens analyzed in this report are limited to word-initial voiceless stops, followed by a low back vowel in stressed syllables. Tokens were randomized and then arranged in a list with the words appearing three separate times. Aspiration was measured from the burst to the onset of voicing(VOT). Both the first language (Ll) tokens and second language (L2) tokens were compared for each speaker and between the two groups of language speakers. Results indicate that the Spanish speakers, as a group, were able to reach the accepted target language VOT of English, but English speakers were not able to reach the accepted range for Spanish, in spite of statistically significant changes of p<.OOl by speakers in both groups of learners. A closer analysis of the speech samples revealed wide variability within the speech of native speakers of English. Not only is variability in English due to the wide range of VOT (120 msecs. for English labials, for example) but individual speakers showed different patterns. These results are revealing for the demands requied in experimental designs and the number of speakers and tokens requied for an adequate description of different languages. In addition, a simple report of means will not distinguish the speakers and the respective language learning situation; measurements must also include the RANGE of acceptability of VOT for phonetic segments. This has immediate consequences for the learning and teaching of foreign languages involving aspirated stops. In addition, the labelling of spoken language in speech technology is shown to be inadequate without a fuller mathematical description.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.26 no.1
• /
• pp.89-96
• /
• 2016

TDOA(time delay of arrival) position estimate from acoustic measurement of artillery shell impact is studied in order to develop a targeting evaluation system. Impact position is calculated from the intersections of hyperbolic estimates based on the least square Taylor series method. The mathematical process of Taylor series estimation is known to be robust. However, the concern lays with the accuracy because it is sensitive to the bias caused by the randomness of measurement situation. The measurement error typically occurs from the distortion of waveform, change of travelling path, and sensor position error. For outdoor measurement, a consideration should be made on the atmospheric condition such as temperature and wind which can possibly change the trajectories of rays of sound. It produces wrong propagation time events accordingly. Ray tracing and optimization techniques are introduced in this study to minimize the bias induced by the ray of sound. The numerical simulation shows that the atmospheric correction improves the estimation accuracy.