• Title/Summary/Keyword: school zone

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A study of teaching methods in middle school mathematics in consideration of the Zone of Proximal Development (근접발달영역을 고려한 중학교 수학의 학습지도방안 연구)

  • Kim, Sung-Kyung;Lee, Dong-Won
    • The Mathematical Education
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    • v.44 no.1 s.108
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    • pp.41-65
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    • 2005
  • In this paper we make an experiment in order to test whether the teaching method with the Zone of Proximal Development (ZPD) developed by Vygotsky can be more effective and well applied in the middle school pratces. Based on this investigation, we conclude that ZPD help to efficiently enhance the study of students, in particular, the inferior student group. Moreover, if we divide the student by more precise stoups, the ZPD will be more effective on teaching and learning in middle school. Lastly, we arrive at the conclusion that a continuous teaching with ZPD will improve the student attitude positively in solving mathematical problem even it does not appeared apparently on this test.

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DISSIMILAR FRICTION-STIR WELDING OF ALALLOY 1050 AND MGALLOY AZ31

  • Park, Seung Hwan C.;Masato Michiuchi;Yutaka S. Sato;Hiroyuki Kokawa
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.534-538
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    • 2002
  • Dissimilar friction stir welding of aluminum (AI) alloy 1050 and magnesium (Mg) alloy AZ31 was successfully done in the limited welding parameters. The dissimilar weld showed good quality and facility compared to conventional fusion weld. Transverse cross section perpendicular to the welding direction had no defects. The weld was divided into base material of Al alloy, an irregular shaped stir zone and base material of Mg alloy. The irregular shaped stir zone was roughly located around the initial weld center. The weld interface near plate surface shifted from initial weld centerline to the advancing side. Hardness profile of the weld was heterogeneous, and the hardness value of the stir zone was raised to about 150 Hv to 250 Hv. The mixed phase was identified to intermetallic compound $Mg_{17}$Al$_{12}$ using x-ray diffraction method, energy dispersive x-ray spectroscopy (EDX) and electron probe micro analysis (EPMA). The formation of intermetallic compound $Mg_{17}$Al$_{12}$ during FSW causes the remarkable increase in hardness value in the stir zone.one.

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A Study on Development of Interpretive Structure Modeling(ISM) for Potential Risk Factors in School Zone (ISM에 의한 어린이 보호구역의 잠재위험 요인 구조화 모형 구축)

  • Park, Yu Kyung;Chung, Hyun Jung;Kim, Young Ji;Kum, Ki Jung
    • International Journal of Highway Engineering
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    • v.14 no.6
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    • pp.93-101
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    • 2012
  • PURPOSES : This study is to develop ISM for potential risk factor in School Zone. METHODS : Based on the literature review, the Analytic Hierarchy Process (AHP) has been used most widely. However, it is difficult to apply in practice because the AHP results have the characteristics of the independence between each element and the interlayer can not explain the interrelationship. The Network Analysis Process (ANP) is possible to analyze the relationship between the elements and the network through the feedback. But, the reliability of the analysis fall because of complicated pair of comparison, also it is difficult to solve the super matrix. In this study, the complicated relationship between each element is inquired through the Interpretive Structural Modeling (ISM). RESULTS : The methodology of ISM is developed to remove the children's potential risk factors in school zone. CONCLUSIONS : It is possible to remove the children's potential risk factors from low level to high level step by step and improve safety. Through this, risk factors can be removed from the low-level, and upper-level will automatically improve.

Development of a Modular Structured Controller for a Commercial AUV (상업용 자율무인잠수정의 안전운행을 위한 모듈러 구조 제어기 개발)

  • Ji, Sang-Hoon;Jung, Yeon-Soo;Kim, Ji-Min;Lee, Beom-Hee;Woo, Jong-Sik;Joo, Young-Seok
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.331-334
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    • 2006
  • This paper deals with the ways how the AUV is composed of sub-modules to be fault-tolerant during the mission. The emergency situations can be classified into several parts according to the zones where the situations take place - sensor zone, actuator zone, interpreter zone, and communication zone. This paper explains how each element of emergency situation is detected, contained and treated, and as a result, introduce the modular structured AUV controller for the autonomous cruising.

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A study of learning attitude and problem-solving abilities of middle school students in consideration of the Zone of Proximal Development at after school class (방과 후 수업에서 근접발달영역을 고려한 수업이 학습태도와 문제해결력에 미치는 영향 연구 - 중학교 1학년 함수를 중심으로 -)

  • Lee, Joong-Kwoen;Kang, Ka-Young
    • Journal of the Korean School Mathematics Society
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    • v.14 no.4
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    • pp.519-538
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    • 2011
  • The purpose of this study is to test whether the teaching method with the Zone of Proximal Development (ZPD) proposed by Vygotsky can be more effective at learning attitudes and problem-solving abilities in the middle school's after school class. This study find that there is meaningful difference between before and after learning attitudes and problem-solving abilities of control group students. This results accord closely with expected of after school as mentioned earlier.

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Shaping Ability of Four Rotary Nickel-Titanium Instruments to Prepare Root Canal at Danger Zone (네 가지 전동 Ni-Ti 파일의 danger zone에서의 근관성형력)

  • Choi, Seok-Dong;Jin, Myoung-Uk;Kim, Ki-Ok;Kim, Sung-Kyo
    • Restorative Dentistry and Endodontics
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    • v.29 no.5
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    • pp.446-453
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    • 2004
  • The aim of this study was to evaluate the shaping abilities of four different rotary nickel-titanium instruments with anticurvature motion to prepare root canal at danger zone by measuring the change of dentin thickness in order to have techniques of safe preparation of canals with nickel-titanium files. Mesiobuccal and mesiolingual canals of forty mesial roots of extracted human lower molars were instrumented using the crown-down technique with ProFile, $GT^{TM}$ Rotary file, Quantec file and $ProTaper^{TM}$. In each root, one canal was prepared with a straight up-and-down motion and the other canal was with an anticurvature motion. Canals were instrumented until apical foramens were up to size of 30 by one operator. The muffle system was used to evaluate the root canal preparation. After superimposing the pre- and post-instrumentation canal. change in root dentin thickness was measured at the inner and outer sides of the canal at 1. 3, and 5 mm levels from the furcation. Data were analyzed using two-way ANOVA. Root dentin thickness at danger zone was significantly thinner than that at safe zone at all levels (p < 0.05). There was no significant difference in the change of root dentin thickness between the straight up-and-down and the anticurvature motions at both danger and safe zones in all groups (p > 0.05). ProTaper removed significantly more dentin than other files especially at furcal 3 mm level of danger and safe zones (p < 0.05) Therefore, it was concluded that anticurvature motion with nickel-titanium rotary instruments does not seem to be effective in danger zone of lower molars.

Estimation of Fatigue Life in Butt-Welded Zone of SM45C Steel Rod (강 봉(SM45C) 맞대기 용접부의 피로수명 평가)

  • Oh, Byung-Duck;Lee, Yong-Bok
    • Journal of Welding and Joining
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    • v.26 no.3
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    • pp.45-50
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    • 2008
  • SM45C steel rods being used generally for power transmission shafts and machine components was selected and welded by Butt-GMAW(Gas Metal Arc Welding) method. An estimation of fatigue life was studied by constructing S-N curve. Fatigue strength of base metal zone showed higher values than one of weld zone in low cycles between $10^4$ and $10^6$cycles. However, significant decrease in fatigue strength of base metal was found around $10^6$cycles, which were almost same as one of heat affected zone. This decrease was attributed that initial residual stress of the steel rods distributed by drawing process was diminished by continually applied load, and resulted in softening of base metal. The fatigue limit of the weld zone was highest in the boundary between deposited metal zone and heat affected zone, and followed by in the order of deposited metal zone, base metal zone, and heat affected zone. Based on these results, it is revealed that the stress for safety design of machine components using SM45C butt-welded steel rods must be selected within the region of the lowest fatigue limit of heat affected zone.

Analysis of Heating Energy in a Korean-Style Apartment Building 3 : The Effect of Room Condition Settings (한국형 아파트의 난방에너지 분석 3 :실내설정조건의 영향)

  • Park, Yoo-Won;Yoo, Ho-Seon;Hong, Hi-Ki
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.8
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    • pp.722-728
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    • 2005
  • The present paper deals with heating energy estimation in Korean-style apartments, paying special attention to the effect of room condition settings. Two types of heating modes are considered: continuous single-zone and scheduled multi-zone. In the latter, zones during unoccupied periods remain unconditioned. Also analyzed are sensitivities in heating energy with respect to the air change rate and the set temperature. The energy use is estimated with TRNSYS 15, a dynamic load calculation program. Heating energy for the actual residential condition (1.0 ACH and $24^{\circ}C$) appears to be nearly the same as that for a typical design standard (1.5 ACH and $20^{\circ}C$). The air change rate affects heating energy as sensitive]y as the set temperature. For all the simulated cases, the scheduled multi-zone heating mode is more energy-efficient than the continuous single-zone. Heating energy depends appreciably on the shading factor. It is expected that considerable heating energy for apartment houses can be saved by employing a multi-zone mode along with appropriate control devices.

Change in Fracture Toughness within Heat-Affected Zone of SA-Welded 9% Ni Steel (LNG 저장탱크 내조용 9% Ni강의 SAW 용접열영향부내 파괴인성 변화 평가)

  • Jang, Jae-Il;Lee, Jeong-Seok;Lee, Baek-U;Ju, Jang-Bok;Gwon, Dong-Il;Kim, U-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.3
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    • pp.528-536
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    • 2002
  • As one step for the safety performance of LNG storage tank, the change in fracture toughness within the X-grooved weld heat-affected zone (HAZ) of newly developed 9% Ni steel, which was submerged arc (SA)-welded, was investigated. Both crack initiation fracture toughness and crack arrest fracture toughness were evaluated by the crack tip opening displacement (CTOD) tests and compact crack arrest (CCA) tests. As the evaluated region approached the fusion line, each test result shorted different tendency, that is, crack initiation toughness decreased while crack arrest toughness increased. The results were discussed through the observation of the microstructural change.

Optimizing Zone-dependent Two-level Facility Location Problem (Zone을 고려한 2단계 시설배치 계획 최적화)

  • Lim, Sung-Hoon;Sung, Chang-Sup;Song, Sang-Hwa
    • IE interfaces
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    • v.24 no.4
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    • pp.341-350
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    • 2011
  • This paper considers a problem of locating both distribution centers and retailers in a zone-dependent two-level distribution network where either a distribution center or a retailer should be located in each zone. Customer demands of each zone should be satisfied directly from either its own distribution center or its own retailer being supplied from a distribution center of another zone. The objective of the proposed problem is to minimize total cost being composed of distribution center/retailer setup costs and transportation costs. In the analysis, the problem is proved to be NP-hard, so that a branch-and-bound algorithm is derived for the problem. Numerical experiments show that the proposed branch-and-bound algorithm provides the optimal solution efficiently for some small problems.