• Title/Summary/Keyword: presumption

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Layer Interface Analysis of Multi-Layered Soils by Numerical Methods (수치해석에 의한 다층토 압밀의 경계요소면 해석)

  • 김팔규;류권일;구기욱;남상규
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.349-356
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    • 1999
  • In general, the term soft ground includes clayey soils, which have large compressibility and small shear resistance due to the external load. All process of consolidation in compressible soils can be explained in terms of a transfer of load from an incompressible pore-water to a compressible soil structure. Therefore, one of the most important subjects about the characteristics of the time-dependent consolidation of the clay foundation by the change of load may be the presumption of the final settlement caused by consolidation and the degree of consolidation according to the time. The problems of discontinuous layer interface are very important in the algorithm and programming for the analysis of multi-layered soils using a numerical analysis, finite difference method. Better results can be obtained by the Process for discontinuous layer interface, since it can help consolidation analysis to model the actual ground. The purpose of this paper Provides an efficient computer algorithm based on numerical analysis using finite difference method(F.D.M.) which account for multi-layered soils to determine the degree of consolidation and excess pore pressures relative to time and positions more realistically.

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The Effects of Joining Factors on Strength of Al 6061 Alloy in FSW (Al 6061 합금의 마찰교반용접 시 접합변수가 강도에 미치는 영향)

  • Kang, Dae-Min;Lee, Dai-Yeal;Park, Kyoung-Do
    • Journal of Power System Engineering
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    • v.21 no.5
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    • pp.86-91
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    • 2017
  • Friction Stir Welding (FSW) is useful technique to join aluminum alloy with energy efficient and environment friendly. In this paper, the design of experiment with three-way factorial design was adopted for optimum conditions of welding variables in the FSW of Al 6061 alloy. Tools of shoulder diameter of 9, 12, 15 mm and pin length of 1.5 mm were used. Also the material's dimension for welding were $2{\times}100{\times}150mm$, and the tensile specimens were worked by water-jet technique. Welding variables were shoulder diameter, rotating speed and travel speed of tool. From the results of this work, the welding factor influenced on yield strength most was travel speed and the optimum condition for FSW was predicted as the shoulder diameter of 15 mm, welding speed of 500 mm/min and rotating speed of 2,000 rpm. Also the presumption range of yield strength at optimal condition of reliability 99% was estimated to $207.19{\pm}9.91MPa$.

A Study on Non-propagating Crack in Fatigue Behavior of Pure Titanium (공업용 순 티타늄의 피로거동에서 정류균열에 관한 연구)

  • Kim, Dong-Yeol;Kim, Jin-Hak;Kim, Min-Geon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.4 s.175
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    • pp.1001-1006
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    • 2000
  • To verify the existing theory, non-propagating crack(NPC) does not exist in Ti which fulfills the good conditions for being of NPC, NPC detection in Ti was tried out. Also, the conception of fatigue limit in Ti and a main cause for NPC being were inquired. NPC was detected in both sharp notch root ( $\rho$=0.02mm) and micro pit (diameter = 0.25mm) which held fast to the end under stressing of fatigue limit. Therefore, the existing theory was identified as mistake. But, NPC can not be detected in smooth specimen. This fact would be due to the presumption that NPC is very small or crack does not initiate in smooth specimen. Anyway, the fatigue limit of Ti does not correspond to critical stress of crack initiation but correspond to critical stress of NPC growth. Measurement on the COD of NPC in Ti showed that the crack tip was closed even under the peak stress level at fatigue limit. But, after stress relieving annealing crack tip was opened. Consequently, compressive residual stress which is induced around the crack tip is considered to be the factor causing the NPC being.

The Ways to Utilize Teaching Materials for Gifted Students' Creativity Improvement (영재학생의 창의성 신장을 위한 교수매체의 활용 방안)

  • Bang, Seung-Jin;Lee, Sang-Wun
    • Communications of Mathematical Education
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    • v.21 no.1 s.29
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    • pp.81-105
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    • 2007
  • We need questions that have various answers, not one answer by just mechanical calculation, to improve students' creativity. Such questions usually require inquiry, presumption, logical inference and a variety of problem solving tactics. These questions will be even more effective when they can provide students with multiple experiences by making them engage in lots of activities. We have to make use of diverse teaching aids and tools, or teaching materials in order to get these results. This research searches for teaching materials which improve gifted students' creativity as well as the ways to utilize 4D Frame. Furthermore we intend to present the ways to put such materials and 4D frame into practical use.

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Studies on the Comparison of Physicochemical Properties and the Presumption of Sensory Quality of Japonica Rice Varieties Cultivated in Korea and Japan (한국과 일본의 자포니카종 쌀에 대한 이화학적 특성의 비교 및 관능품질의 추정에 관한 연구)

  • 홍원표;이성갑;박승남
    • The Korean Journal of Food And Nutrition
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    • v.14 no.6
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    • pp.596-604
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    • 2001
  • Twelve varieties of Korean rice and ten varieties of Japanese rice were selected. After being milled. they were analyzed about various physicochemical properties such as moisture, protein and amylose, a -amylase activity, gelatinization properties. And after being cooked with proper amount of water texture and other physical properties were measured by Texturometer, Tensipresser and Rheolograph-micro. Finally the sensory evaluation test was carried out. The results were as follows. 1. In case of protein contents, amylose contents and $\alpha$-amylase activity, Korean rice had a slightly higher value than Japanese As a consequence. Korean rice showed a little stronger hardness and a little weaker stickiness compared with Japanese rice. 2. Amylose contents showed very high correlation with other physicochemical properties and peak viscosity and gelatinization temperature of RVA, the ratio of stickiness to hardness( -Hl/Hl ) of Texturometer and the tan $\delta$(the ratio of dynamic loss to dynamic viscoelasticity) of Rheolograph-micro showed high correlation with other analyzed properties. 3. The ( -/+)work balance of low compression test(25% ) of Tensipresser analysis(texture analysis on the surface of cooked rice) and tan f of Rheolograph-micro showed very high correlation with sensory evaluation results. By using this parameters as major independent variables, some trials to derive high confidence multiple regression equations were accomplished. By the equations it would be possible to make an approximate pre-estimate of eating quality for unknown japonica rice.

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Cultural Exchange and Its Externalities on Korea-Africa Relations: How Does the Korean Wave Affect the Perception and Purchasing Behavior of African Consumers?

  • Ochieng, Haggai Kennedy;Kim, Sungsoo
    • East Asian Economic Review
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    • v.23 no.4
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    • pp.381-407
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    • 2019
  • The Korean wave has become a global phenomenon whose effect has been widely studied in Asia, Europe and the US. However the presumption of cultural distance makes it appear unlikely that the Korean wave could gain traction among African consumers of cultural products. As such, a dearth of evidence exists on the effects of the wave in Africa. This paper examines the effect of the wave in East African countries employing both descriptive and Probit model analyses. The results show that, contrary to conventional beliefs, most Africans surveyed perceive value proximity with Korea through the values conveyed in Korean dramas, movies and music. Confucius values, such as filial piety, family love and respect for the elderly are the most appealing to the East African audience. Importantly, contact with Korean wave contents contributes to the respondents' disposition to form favorable attitude towards Korea. The African consumers of Korea's cultural products are equally likely to purchase other Korean commercial products. These results remotely suggest that Hallyu may be a tool for advancing Korea's soft power towards Africa and could generate positive economic externalities.

Global Value Chain in East Asia Under "New Normal": Ideology- Technology-Institution Nexus

  • Choi, Byung-il
    • East Asian Economic Review
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    • v.24 no.1
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    • pp.3-30
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    • 2020
  • This paper analyzes how the current Global Value Chain (GVC) of East Asia has been established, and attempts to project the future trajectory of GVC under New Normal in the global trading system. For this purpose, the framework of Ideology-Technology-Institution nexus is presented with focus on the dynamics of interplay between ideology and technology, duly recognizing the dual-aspect of technology- a platform for business and also for national defense. The paper analyzes how the Information and Communication Technology (ICT) of the 1990s played a role of "facilitator" in shaping the GVC of East Asia, where China plays 'factory for final assembly' and the US plays 'the largest consumer'. Under New Normal, digital technology is likely to play the opposite role of "disrupting" the GVC of East Asia, unlike ICT. The paper explores the mechanism behind this great disruption. What is driving New Normal is the US-China power competition, seeking for dominance in East Asia and beyond. This paper argues that New Normal is not temporary shock, but will last for some time. Under this presumption, the paper presents three scenarios for the future trajectory of GVC in East Asia.

THE ORBIT DETERMINATION OF LEO SATELLITES USING EXTENDED KALMAN FILTER (확장 칼만 필터를 이용한 LEO 위성의 궤도결정 방법)

  • 손건호;김광렬;최규홍
    • Journal of Astronomy and Space Sciences
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    • v.12 no.1
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    • pp.133-142
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    • 1995
  • We studied the nonlinear estimation problem of extended Kalman filter and appled this method to LEO satellite system. Through this method the performance of extended Kalman filter was analyzed. There were certain presumption taken; J2 and atmospheric drag were simply considered in the dynamic model of LEO satellite and the system noise error of $\sigma_r$=150m, $\sigma_r$=10m/s was presumed in the observation data. As results of this simulation, the overall state estimation errors of extended Kalman filter were within the presumed error range and also the ability of performance was maximized when the condition was the state process noise Q has the 1/10 level of covariance matrix Po.

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Intractable Hiccup as the Presenting Symptom of Cavernous Hemangioma in the Medulla Oblongata : A Case Report and Literature Review

  • Lee, Kyung-Hwa;Moon, Kyung-Sub;Jung, Min-Young;Jung, Shin
    • Journal of Korean Neurosurgical Society
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    • v.55 no.6
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    • pp.379-382
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    • 2014
  • A case of intractable hiccup developed by cavernous hemangioma in the medulla oblongata is reported. There have been only five previously reported cases of medullary cavernoma that triggered intractable hiccup. The patient was a 28-year-old man who was presented with intractable hiccup for 15 days. It developed suddenly, then aggravated progressively and did not respond to any types of medication. On magnetic resonance images, a well-demarcated and non-enhancing mass with hemorrhagic changes was noted in the left medulla oblongata. Intraoperative findings showed that the lesion was fully embedded within the brain stem and pathology confirmed the diagnosis of cavernous hemangioma. The hiccup resolved completely after the operation. Based on the presumption that the medullary cavernoma may trigger intractable hiccup by displacing or compression the hiccup arc of the dorsolateral medulla, surgical excision can eliminate the symptoms, even in the case totally buried in brainstem.