• The Journal of Sustainable Design and Educational Environment Research
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• v.17 no.3
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• pp.26-34
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• 2018

This research is a pre-research to find out profit module of 20 students in a classroom. I researched the widths of passages in the 30 classrooms of 5 elementary schools in Nothern Kyeonggi-do. I found the conclusions as follows. 1st, the area of 1 student's unit is $650(W){\times}950(D)$ 2nd, most of classrooms' students table placements are one-way types(77%). U-types are 13%. group study-types are 7% 3rd, The width between blackboard and front student's table is 2.08m. The width of passage between back seat and backboard is 1.12m. The width of passage between side wall and near student's table is 0.89m. The width of passage between window and near student's table is 0.74m. The width of vertical passage(A) between student's tables is 0.68m. The width of vertical passage(B) between student's tables is 0.7m. 4th, The area of teachers' is $2.1m{\sim}2.25m{\times}2.1m=4.41{\sim}4.73m^2$

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.694-701
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• 2018

Larger crack widths can be observed more in FRP-reinforced concrete members than in steel-reinforced concrete members as a result of the lower elastic modulus and bond strength of FRP reinforcement. The ACI 440.1R-15 design guide provides equations derived as the maximum bar spacing to control the crack widths indirectly. On the other hand, it is not concerned with long-term effects on the crack control design provisions. This study provides suggestions for how to incorporate time-dependent effects into the crack width equation. The work presented herein includes the results from 8 beams composed of four rectangular and T-shaped FRP-reinforced concrete beams tested for one year under four-point bending. Over a one year period, the crack widths increased as much as 2.6~3.0 times in GFRP and AFRP-reinforced specimens and 1.1~1.4 times in the CFRP-reinforced specimens compared to steel-reinforced specimens. In addition, the average multiple for crack width at one year relative to the instantaneous crack width upon the application of the sustained load was 2.4 in the specimens with a rectangular section and 3.1 in the specimens with a T-shaped section. As a result, it is recommended conservatively that the time-dependent coefficient be taken as 2.5 for the rectangular beams and 3.5 for T-beams.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.4
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• pp.60-69
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• 2020

This research is a preliminary study to find out the module of 20 students in a classroom. This research investigated the widths of passages in the 30 classrooms of 5 elementary schools in Namyangju City, Korea. The conclusions were as follows: First, the area of unit for 1 student was 650 (W) × 950 (D). Second, the desk placements for most classrooms were one-way types (87%), and group-study types constituted 13%. Third, the width between the blackboard and the very front desk was 2.17 m. The width of passage between the very back seat and the backside lockers was 1.32 m. The width of passage between the sidewall and the nearby desk was 0.8 m. The width of passage between the window and the nearby desk was 0.8 m. The average widths of 2 vertical passages between the desks were respectively 0.67 m and 0.68 m. Fourth, the area of the teacher was 2.1-2.25 m × 2.16 m = 4.5-4.8 ㎡.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.135-141
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• 2014

In this paper, the device design guideline to reduce the threshold voltage variation with fin width in junctionless MuGFET has been suggested. It has been observed that the threshold voltage variation was increased with increase of fin width in junctionless MuGFETs. To reduce the threshold voltage variation with fin width in junctionless MuGFETs, 3-dimensional device simulation with different gate dielectric materials, silicon film thickness, and an optimized fin number has been performed. The simulation results showed that the threshold voltage variation can be reduced by the gate dielectric materials with a high dielectric constant such as $La_2O_3$ and the silicon film with ultra-thin thickness even though the fin width is increased. Particularly, the reduction of the threshold voltage variation and the subthreshold slope by reducing the fin width and increasing the fin numbers is known the optimized device design guideline in junctionless MuGFETs.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1266-1270
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• 2006

최근 도시개발이나 주택단지개발사업의 경우 토지이용의 극대화 및 경제적인 측면에서 저류지의 면적을 충분히 확보하기 어려우므로 첨두홍수량 조절방식인 하도외(off-line) 저류지가 검토되고 일부 설치되고 있으며, 증가된 홍수량을 저류지로 전환하는 방법에는 일반적으로 횡월류위어가 이용되고 있다. 현재 off-line 저류지 횡월류량 산정시 사용되고 있는 De Marchi공식의 유량계수를 0.623이라는 고정된 값을 사용하고 있으나, 횡월류위어의 유량계수는 본류 흐름 조건 및 위어의 기하학적 조건에 따라 달라지기 때문에 이에 대한 문제점을 갖고 있다. 또한 횡월류부의 적정폭이 제시되어 있지 않으므로 계획빈도 이상의 수위가 전량 저류지로 유입되는지 이에 대한 실험 및 검증이 요구된다. 본 연구에서는 수리실험을 통하여 설계빈도 이상의 초과홍수량을 전량 월류시킬 목적으로 사용되는 off-line 저류지 횡월류위어의 적정폭을 산정하고, 본류 흐름 조건 및 위어의 기하학적 조건 등을 고려한 횡월류위어의 유량계수를 산정하였다. 적정폭 산정 결과 본 실험조건에서는 횡월류 위어폭이 본류폭의 6배인 3.6m(L/B=6.0)이상일 때 모든 조건에서 위어정점부 이상의 수위에 대한 유량을 전량 월류시킬 수 있는 것으로 나타났다. L/B=6.0일 때 $Fr_u,\;W/y_u$와 $S_o$를 고려한 중회귀분석을 통해 off-line 저류지에 적합한 횡월류 위어의 유량계수식을 제안하였으며, off-line 저류지의 횡월류위어 설계시 활용할 수 있을 것으로 판단된다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.919-928
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• 2010

Four patterns for width adjustment were studied with an aim to increase the width-adjustment speed in continuous casting. The main goals are to minimize the actuating force of a WAM actuator, to develop a deformation analysis model of a solidified shell in the mold, and to induce the main limit factor for the speedup of width adjustment. On the basis of the width-adjustment experiment, the notable features of four patterns types were considered, and we compared the corresponding actuating forces. For comparing the driving forces of the patterns, during the experiment, the same casting speed was maintained for each pattern. To optimize the parameter of the deformation analysis model of the solidified shell, the experiment results were applied to them. To speed up width adjustment and to reduce the driving force, we controlled the pattern parameters. The most effective pattern was the fast-mode pattern, and the taper was the main parameter that helped reduce the driving forces during the motion of the actuator.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.1
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• pp.8-14
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• 2012

The device performances of n-channel MuGFET with different fin numbers and fin widths but the total effective channel width is constant have been characterized. Two kinds of Pi-gate devices with fin number=16, fin width=55nm, and fin number=14, fin width=80nm have been used in characterization. The threshold voltage, effective electron mobility, threshold voltage roll-off, inverse subthreshold slope, PBTI, hot carrier degradation, and drain breakdown voltage have been characterized. From the measured results, the short channel effects have been reduced for narrow fin width and large fin numbers. PBTI degradation was more significant in devices with large fin number and narrow fin width but hot carrier degradation was similar for both devices. The drain breakdown voltage was higher for devices with narrow fin width and large fin numbers. With considering the short channel effects and device degradation, the devices with narrow fin width and large fin numbers are desirable in the device layout of MuGFETs.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.2
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• pp.116-122
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• 2015

A simulation is applied to evaluate sea surface observations such as wave heights and surface currents by using a microwave Doppler radar. It is reported that the microwave irradiation width on the sea surface and Fourier transform time taken to sample data for frequency analysis affect Doppler spectra. To investigate the influences by these parameters, Doppler spectra are simulated with various numerical sea surface waves with currents. From the results, in the case of the microwave irradiation width is five times smaller than the wavelength of the sea surface wave, and the Fourier transform time is also five times shorter than the period of the sea surface wave, there is a possibility to measure wave heights accurately with a Doppler radar. In addition, relative surface currents can be estimated by analysis of long Fourier transform time. The simulation results showed the appropriate observing conditions with a microwave Doppler radar.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.122-123
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• 2010

2000~2009년 동안 격월로 관측한 수온 관측 자료를 분석하여 표층 수온이 10년 동안 약 $1{\sim}1.9^{\circ}C$ 상승하는 경향을 관찰하였다. 상승폭이 해역마다 약간의 차이를 보이고 있는데 부산해역은 약 $1.5^{\circ}C$, 여수해역은 약 $1.7^{\circ}C$, 제주북부에서도 약 $1.7^{\circ}C$의 상승폭을 보임으로서 남해 동쪽보다는 서쪽해역의 상승폭이 약간 높게 나타났다. 남해 연안수의 평균 수온이 증가하는 추세경향으로 미루어 볼 때 남해 수온전선이 약해지게 되어 결과적으로 연안쪽으로 밀릴 것으로 추정된다. 제주도 모슬포는 약 $1.9^{\circ}C$ 가 상승하였으며 제주도 성산포는 2004~2009년 동안 약 $1.2^{\circ}C$ 상승하는 추세를 보였다. 이와 같은 수온의 변동성은 조위관측소에서 관측된 수온에서도 확인할 수 있는데 부산은 $0.2^{\circ}C$/8년, 여수 $0.4^{\circ}C$/10년, 제주북부는 $1.5^{\circ}C$/10년, 모슬포와 성산포는 $1^{\circ}C$/6년, 서귀포는 $1.7^{\circ}C$/8년 상승폭을 보인다. 조위관측소의 수온 상승폭보다 한국연안해류조사의 수온 상승폭이 약간 높게 나타나고 있는데 이는 관측소의 위치가 해안가에 있는 반면 연안해류조사는 선박을 이용하여 외해쪽에서 수온을 관측하기 때문에 고온 고염의 대마난류(Tsushima Warm Current) 영향을 더 많이 받았기 때문으로 볼 수 있다. 해수의 수온 상승 현상은 증가율이 약간 낮기는 하지만 50m 수심에서도 나타나고 있다. 부산해역, 여수해역, 제주북부 해역은 모두 약 $1.2^{\circ}C$의 상승폭을 보였으며, 제주도 성산포는 약 $1.1^{\circ}C$인 반면, 모슬포 해역에서는 약 $1.5^{\circ}C$로 상승추이가 크게 나타났다. 이와 같이 남해 연안수가 표층과 저층에서 동반 상승했다는 것은 대마난류의 세력이 강해졌다는 것을 보여주는 지시자(indicator)로서 최근 제주도와 남부지방의 기후온난화와 관련이 있을 것으로 추정된다. 하지만 상승률은 관측기간이 길어질수록 작아지는 경향이 있기 때문에 남해의 물리적 특성 변화를 보다 명확히 규명하기 위해서는 좀 더 장기적인 자료가 필요하다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.481-485
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• 2002

In this study, we fabricated the PBH-LD by meltback method using the LPE. The PBH-LDs are analyzed the leakage current that flows through leakage current path like the p-n diode and p-n-p-n current blocking layer. We observed the variation of threshold current with the leakage width $W_{ι}$. As a consequence, we confirmed that the threshold current became low in the decrease of the leakage width and in the increase of the ratio of specific resistivity of leakage region to active region. We also compared between the calculated threshold current in the absence of leakage region and the measured threshold current in the device. As a result, the ratio of specific resistivity was about 0.5 in the measured LDs, which have the width of a active layer of 1.4${\mu}{\textrm}{m}$ and leakage width of 0.6${\mu}{\textrm}{m}$.