• 한국지반공학회지:지반
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• 제9권1호
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• pp.59-68
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• 1993

In deep excavations for creation of underground spaces, it would be difficult to predict earth pressure, especially multilayered ground including rock strata. The earth pressures and displacements on the retention walls are measured by load cell, strain gauge and inclinometer which were installed at struts or anchors at 4 deep excavation sites in Seoul area. In this paper, the measured earth pressure from the struts or anchors are compared with Peck's empirical values, and the coefficient of the earth pressures for each strata and horizontal wall displacement are investigated. The coefficient of earth pressure distribution, a(0.65zka), in the flexible and the rigid walls was about 74% and 88% of Peck's value respecitively. The measured earth pressure distributions for the 4 sites showed about 70%∼80% of Peck's empirical values and the average earth pressure coefficients based on the measured data were 0.3 for the felted layer, 0.23 for the weathered rock and 0.19 for the weak rock. The maximum w리1 displacements were found to be less 0.2% of excavation depth.

• Journal of the Korean Wood Science and Technology
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• 제19권3호
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• pp.35-44
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• 1991

In this study, thickness 40mm glulams were composed of thickness 5mm, 10mm Quercus laminas and Pinus koraiensis laminas to study on the effect of load variation on transition of neutral axis of laminated veneer lumber(LVL). The transition of neutral axis was examined by strain variation, which was checked by strain gauge. amplifier, recorder, and strain meter. The elasticity of glulam was estimated by E = $\Sigma(E_i\;I_ i)$/I and this estimated elasticity values were compared with the elasticity values of glulam in bending. The result obtained can be summarized as follows: 1. The location of neutral axis of glulam was effected by glulam composition methods 2. The neutral axis did not shift by load variation within proportional limit. 3. The estimated elasticity of glulam by E = $\Sigma(E_i\;I_ i)$/I showed much lower value than the elasticity of glulam in bending.

• Journal of Welding and Joining
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• 제19권5호
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• pp.548-554
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• 2001

The restraint force is required an accurate measurement and analysis to protect weldment from residual stress. Also, this residual stress caused by clacks in weldments are often observed in the weldments of large size nozzles or radial tanks after welding. This paper is preformed on the study of evaluation of welding restraint forces using load cell with STS thin plate which are using pressure vessel steel in the industry field. As a result of this study, as the welding currents are higher and the welding speeds are more slowly, the magnitude of restraint force in process of the flat plate welding hows to be more large. Also, the temperature in process of melting is increasingly rising, then the restraint forces exhibit the compressive forces, whereas the restraint forces during cooling represent extensional force.

• 제어로봇시스템학회논문지
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• 제19권11호
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• pp.991-997
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• 2013

In this paper, we propose a CFWC (CCD and fuzzy PID based width control) scheme to obtain the desired delivery width margin of a vertical rolling mill in hot strip process. A WMS(width measurement system) is composed of two line scan cameras, an edge detection algorithm, a glitch filter, and so on. A dynamic model of the mill is derived from a gauge meter equation in order to design the fuzzy PID controller. The controller is a self-learning structure to select the PID gains from the error and error rate of the width margin. The effectiveness of the proposed CFWC is verified from simulation results under a width disturbance of the entry in the mill. Using a field test, we show that the performance of the width control is improved by the proposed control scheme.

• Earthquakes and Structures
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• 제21권6호
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• pp.653-667
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• 2021

In this study, cyclic loading tests were conducted on the precast concrete (PC) wide beam (WB)-column joints. Two beam-column joint specimens were fabricated with the arrangement and anchorage details of the reinforcing bars penetrating the beam and column as variables. Through a cyclic loading test, the lateral load-story drift ratio responses, seismic performance characteristics (e.g., ductility, overstrength factor), energy dissipation, strength and stiffness degradations of each specimen were compared and analyzed based on the various indices and the current structural codes (ACI 318-19 and ACI 374.1-05 report). In addition, the shear lag effect was confirmed through the gauge values of the PC beam, and the differences in seismic performance between the specimens were identified on that basis.

• 한국제4기학회지
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• 제14권2호
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• pp.87-99
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• 2000

설악산에서 작성된 8개 지역 연륜연대기 중 강수량 복원에 적합한 대승폭포 인근 2개 지역(해발고 700~900m)의 연륜연대기를 이용하여 253년간 (A.D. 1746~A.D. 1998)의 5월~6월 총강수량을 복원하였다. 1765~1800년(최장 가뭄), 1835~1845년, 1890~1910년, 1920~1940년, 1980~1995년이 건조기로 나타났으며, 1810~1830년, 1860~1890년, 1950~1970년이 습윤한 시기로 나타났다. 장기간으로 보았을 때, 18세기 후반기는 건조한 기간이었으며, 19세기의 5월~6월 총강수량이 250mm로 20세기의 231mm보다 많아 19세기가 20세기보다 상대적으로 습윤하였음을 알 수 있었다. 강수량 변화폭이 19세기가 20세기보다 큰 것으로 관찰되었다. 전 기간에 걸친 주요한 건습 주기는 단기간은 3년, 장기간은 60~80년으로 조사되었다. 서울지방의 측우기 자료와는 1800년대 초를 제외하곤 대체로 일치하였다.

• 한국강구조학회 논문집
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• 제26권3호
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• pp.231-240
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• 2014

축방향 인장력을 받는 T-stub은 T-stub과 긴결재의 재료적 물성 특성, T-stub의 기하학적 형상, 긴결재의 직경과 체결력 등의 변화에 의하여 상이한 거동특성을 나타낸다. 이러한 변화의 영향으로 T-stub은 T-stub 플랜지의 휨항복 후 소성파괴, T-stub 필릿부의 휨항복과 긴결재 파단, 긴결재의 파단 등과 같은 세 가지 파괴양상을 나타낸다. 일반적으로 T-stub 플랜지의 두께가 얇고 긴결재의 게이지 거리가 긴 T-stub은 플랜지의 휨항복 후 소성화에 의하여 T-stub 플랜지의 두께가 두껍고 긴결재의 게이지 거리가 짧은 T-stub보다 에너지소산능력이 우수하다. 이 연구는 T-stub 체결에 사용된 긴결재가 T-stub의 에너지소산능력에 미치는 영향을 파악하기 위하여 3차원 비선형 유한요소 해석을 진행하였다. T-stub 해석모델의 긴결재로는 F10T-M20 고장력볼트와 ${\varnothing}19.05mm$(3/4inch)인 SMA 강봉을 모델링하였고, T-stub의 기하학적 형상은 T-stub 필릿부의 휨항복과 긴결재 파단의 파괴를 나타내도록 선택하였다.

• 대한치과보철학회지
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• 제34권4호
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• pp.746-754
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• 1996

개교증, 절연부 파절, 변색등 심미적 요인으로 라미네이트를 설측연장시 연장길이에 따른 파절강도를 알아보기위해 발거된 60개의 상악 전치의 순면에 3개의 seating form을 형성하고sheet wax를 사용하여 가로 5mm $^*$세로 5mm $^*$두께 0.9mm의 block을 형성하고, 각 군에 따라 I군 : 0.5mm, II군 : 1mm, III군 : 2mm, IV군 : 0mm로 설측 연장 길이를 달리하여 block을 형성 이를 인상채득하여 내화모형을 제작하였다. 여기에 라미네이트용 도재를 2회에 걸쳐 축성 통법대로 소성 제작하였다. block에 맞추어 contouring하고, 내화매몰재를 제거 sandblast처리를 시행하였다. 그후 레진시멘트로 합착하였다. 절치간 각도를 127도로 특별히 제작된 holding device를 이용하여 인스트론 만능시험기에 시편을 거상하고, 분당 0.5mm cross head speed로 파절강도를 측정하여 다음과 같은 결과를 얻었다. 1. 각 군의 평균파절강도는 대조군인 설면으로 연장치 않은 IV군에서 86.95Mpa, 0.5mm 연장한 I군에서 44.98Mpa, 1.0mm연장한 II군에서 27.47Mpa, 2.0mm연장한 III군에서 19.61Mpa의 순으로 나타났다. 2. 모든 실험군 사이에는 통계적으로 유의성 있는 차이를 나타냈고(p<0.01), 이러한 실험 결과로 미루어 보아 라미네이트 디자인시, 설면으로 연장치 않거나, 절연부의 피개가 불가피한 경우에는 설면으로 0.5mm 연장하는 것이 파절 강도면에서 유리하다고 사료된다.

• 교육시설 논문지
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• 제19권4호
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• pp.11-19
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• 2012

The purpose of this study is to gauge the level of awareness of elementary, middle school, and highschool teachers regarding teaching-learning activities, learning space, and support for technology-based instruction in current and future school education, thereby providing essential data for seeking future improvements in the learning environment. Towards this end, a survey questionnaire (sectionalized into teaching-learning activities, learning space, and support for technology-based instruction) was developed. Subsequently the survey was administered to a random sampling of elementary, middle school, and highschool teachers in the Kyonggi, Kangwon, and Chonra Provinces. An in-depth analysis was conducted on the 797 questionnaire responses thus attained, focusing on the teachers' level of awareness regarding teaching-learning activities, learning space, and support for technology-based instruction, the correlation of the findings of the three areas in question, and the differences of the findings according to the circumstances of those surveyed. Based on the results, the authors of this study propose the following: First, that school administrators take into account the level of awareness of frontline teachers regarding teaching-learning activities, learning space, support for technology-based instruction. Second, efforts should be made to establish a safe and secure learning environment conducive to the synergic interplay of the three areas in question, by realizing true ICT in the classroom. Third, teachers in the classroom must endeavor to achieve a meaningful synthesis between educational programs and teaching-learning activities, as well as to serve as harbingers of improvements in the way we conduct the business of education.

• 한국환경과학회지
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• 제19권11호
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• pp.1375-1384
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• 2010

Growth in population and urbanization has progressively increased the loading of pollutants from nonpoint sources as well as point sources. Especially in case of road regions such as city trunk road, national road and highway are rainfall and pollutants runoff intensive landuses since they are impervious and emit a lot of pollutants from vehicle activity. This research was conducted to investigate the nonpoint sources concentration and quantifying stormwater pollutants which are contained in rainfall runoff water. Three different monitoring sites in Jinju and Changwon city were equipped with an automatic rainfall gauge and flow meter for measuring rainfall and the volume of rainfall runoff. In the case of average EMC value, city trunk road was shown the highest value in target water quality items like as BOD, COD, SS, TN and TP. Or the amount of runoff loads by water quality items showed the highest value in city trunk road. And runoff load in city trunk road was 43.8 times high value compared to highway by value of city trunk road $356.7 mg/m^2$, highway $8.150 mg/m^2$, national road $19.99 mg/m^2$ in the case of BOD.