• Title/Summary/Keyword: Standard section

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Performance Evaluation of Surface Textures on Concrete Pavement (콘크리트 거친면 마무리처리에 따른 공용성 평가)

  • Park, Kwon-Je;Mun, Jun-Beom;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.6 no.1 s.19
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    • pp.1-11
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    • 2004
  • This study tries to propose the most effective pavement texture method through the performance evaluation of variable texture methods. Noise 2$\sim$3dB is reduced in the section of uniform space 18m longitudinal tinning. This result is proved by comparing the magnitude of noise in two sections. The noise of 26mm longitudinal firming section is greater than that of 18mm section by 2$\sim$3dB(A). The skid resistances measured in all test section show the reasonable results. The roughness or all the test sections satisfies AASHTO roughness standard (PrI 16cm/km). The result or questionnaire survey about driving quality shows that the longitudinal tinning is the most effective method. As the result of a visual measurement, it is proved that the section applied uniform space 26mm longitudinal tinning and the general section applied uniform space 26mm transverse tinning could drain water effectively. As the result of analysis with the ranking method, the 18mm longitudinal tinning in selected as one of the most effective tinning methods. In addition, 26mm longitudinal tinning, random space transverse tinning, and transverse drag are selected in order.

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Uncertainty analysis for Section-by-Section method of ADCP discharge measurement based on GUM standard (GUM 표준안 기반 ADCP 지점 측정 방법 유량 측정 불확도 분석)

  • Kim, Dongsu;Kim, Jongmin;Byeon, Hyunhyuk;Kang, Junkoo
    • Journal of Korea Water Resources Association
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    • v.50 no.8
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    • pp.521-535
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    • 2017
  • Acoustic Doppler Current Profilers (ADCPs) have been widely utilized for assessing streamflow discharge, yet few comprehensive studies were conducted to evaluate discharge uncertainty in consideration of individual uncertainty components. It could be mostly because it was not easy to determine which uncertainty framework can be appropriate to rigorously analyze streamflow discharge driven by ADCPs. In this regard, considerable efforts have been made by scientific and engineering societies to develop a standardized theoretical framework for uncertainty analysis in hydrometry. One of the well-established UA methodology based on sound statistical and engineering concepts is Guide to the Expression of Uncertainty Measurement (GUM) adopted widely by various scientific and research communities. This research fundamentally adapted the GUM framework to assess individual uncertainty components of ADCP discharge measurements, and subsequently provided results of a customized experiment in a controllable real-scale artificial river channel. We focused particularly upon sensitivities of uncertainty components in the GUM framework driven by ADCPs direct measurements such as depths, edge distance, submerged depth, velocity gap, sampling time, repeatability, bed roughness and so on. Section-by-Section method for ADCP discharge measurement was applied for uncertainty analysis for this study. All of measurements were carefully compared with data using other instrumentations such as ADV to evaluate individual uncertainty components.

A Study on Standard Hanok Design for Rural (농촌 한옥 표준설계도 연구)

  • Kim, Jae-Ung
    • Journal of the Korean Institute of Rural Architecture
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    • v.18 no.1
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    • pp.19-28
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    • 2016
  • This research aimed to suggest a standard design that reflects Hanok design tendency, and present a selective design that can fulfill a building owner's intention beyond the simple function of building permit or report. In addition, this research attempted to become a standard by establishing a criterion in calculating the measurements of section design or primary framework members, in order to be a guideline for designing Hanok in different sizes and forms. The results are as follows. The building area of Hanok standard design was set to be below $85m^2$, with a straight type of $83.16m^2$ and an L-shape of $84.24m^2$. By dividing the plane into a straight type and L-shape, two straight types were suggested: 'general type' and 'large living room type.' The upper floor space, along with the main room and small room, was proposed as an option to be changed into a room where an underfloor heating is installed depending on the building owner's intention. In addition, a criterion for side design and calculation of framework measurements was suggested and applied, while a five-girder design without high pillars was suggested for material-assembling structure. Two types of pillars-circumference and square cylinder-were proposed for the building owner to choose from, and a pointed beam house and ikgong(orthogonally-projected bracket) house were suggested for pojak bracket structure so either of them could be chosen according to the building owner's taste and economic condition. Finally, the sectional size of main materials were divided according to the form of pojak bracket structure to be proposed.

Evaluation of Bonding Strength of Larch Cross-Laminated Timber

  • Song, Yo-Jin;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.44 no.4
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    • pp.607-615
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    • 2016
  • The delamination along the annual ring on the cross-section of laminae and the bonding strength according to the tangential angle between laminae were evaluated for the production of 3-ply cross-laminated timber (CLT) using domestic larch. Since there is no standard for CLT in Korea, the production and test of specimens for bonding strength followed the standard procedure of "Structural glued laminated timber" (KS F 3021). The standard specifies to exclude any measurement from the cracks of timbers resulted from drying or knots during delamination test of the glued laminated timbers. However, the failure of cross-sectional tissues along the annual rings was observed near the glue-line of all specimens during the delamination test. Because this phenomenon can generate defects in the CLT that may be exposed to various temperatures and relative humidities after the actual construction, the delamination percentage was measured by including this wood failure. As a result, the delamination percentage of the CLT which had been combined in such a way that the annual rings of outer lamina were directed inward was the lowest, which was around 13%, regardless of the annual ring direction of the middle lamina. On the other hand, the delamination percentage of the CLT which had been combined in such a way that the annual rings of outer lamina were directed outward was the highest, which was around 26%. Furthermore, end-split occurred in the outer lamina during the drying process of the boiling delamination test, which affected the delamination percentage. Therefore, the soaking delamination test was found to be more appropriate for evaluating the delamination strength of CLT. The block shear strength of larch CLT was $3.9{\pm}0.9$ MPa on average, which was 46% lower than the block shear strength requirement (7.1 MPa) of the standard, but satisfied the criteria of the block shear strength (3.5 MPa) of the European Standard (prEN 16351: 2013).

Phytochemical Standardization and Anti-Anxiety (Izterab-e-Nafsani) study of Aftimoon Hindi (Cuscuta reflexa Roxb.) on An Animal Model

  • Ara, Irfat;Kalam, Mohd Afsahul;Maqbool, Mudasir;Zehravi, Mehrukh
    • CELLMED
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    • v.11 no.3
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    • pp.14.1-14.9
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    • 2021
  • Background: Cuscuta reflexa Roxb is a member of the Cuscutaceae family, and in Unani medicine, it is known as Aftimoon. It is a parasitic plant that can be found growing abundantly on various host plants in India up to 3000 metres in altitude during the rainy season. Unani physicians have been using it for years to cure a variety of illnesses, including psychiatric illnesses like melancholia, schizophrenia, and epilepsy. It has been used to cure hepatitis, palpitations, and skin disorders, among other things. Objective of the study: To evaluate anti-anxiety effect of Cuscuta reflexa Roxb in Swiss Albino mice of either sex. Materials and Methods: A total of 24 Swiss Albino mice weighing 25-35 g were used in this study. Animals were chosen at random and held in their cages for at least 7 days in a standard setting. Group A was given regular saline as a vehicle, Group B was given a hydro alcoholic extract of the lower dose of the test drug, Group C was given a hydro alcoholic extract of the higher dose of the test drug, and Group D was given the standard drug Diazepam 5 mg/kg orally. Aftimoon as hydro alcoholic extract (200 mg/kg and 400 mg/kg body wt.) was given in single and double doses and observed for 7 days. Results: For each parameter in each category, mean and standard deviations were computed. For multiple group comparisons, a one-way ANOVA was used, followed by Turkey's post hoc test. (p<0.05) was used as the significance standard. Conclusion: These results advocate that the Aftimoon as double dose (400 mg/kg body wt.) revealed anti-anxiety effect similar to standard drug.

Applicability of Huff Model & ABM Method for Discharge Capacity of Sewer Pipe (하수관거 통수능 해석을 위한 Huff 모형과 ABM 법의 적용성 분석)

  • Hyun, Inhwan;Jeon, SeungHui;Kim, Dooil
    • Journal of Korean Society of Water and Wastewater
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    • v.36 no.4
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    • pp.229-237
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    • 2022
  • The sewer capacity design have been based on the Huff model or the rational equation in South Korea and often failed to determine optimal capacity, resulting in frequent urban flooding or over-sizing. A time distribution of rainfall (i.e., Huff or ABM method) could be used instead of a rainfall hyetograph obtained from statistical analysis of previous rainfalls. In this study, the Huff method and the ABM method, which predict the time distribution of rain intensity, which are widely used to calculate sewage pipe drainage capacity using the SWMM, were compared with the standard rainfall intensity hyetograph of Seoul. If the rainfall duration was 30 minutes to 180 minutes, the rainfall intensity value calculated by the Huff model tended to be less than the rainfall intensity value of the standard rainfall intensity in the initial 5-10 minutes. As a result, more than 10% to 30% of under-design would be made. In addition, the rainfall intensity value calculated by the Huff model from the section excluding the initial 5-10 minutes of rainfall to the rainfall duration was calculated larger than the value using the standard rainfall intensity equation, which would result in an over-design of 10% to 30%. In the case of a relatively long rainfall duration of 360 minutes (6 hours) to 1,440 minutes (24 hours), it showed an lower rainfall intensity of 60 to 90% in the early stages of rainfall, but the problem of under-design had been solved as the rainfall duration time had elapsed. On the other hand, in the alternating block method (ABM) method, it was found that the rainfall intensity at the entire period at each assumed rainfall duration accurately matched the standard rainfall intensity hyetograph of Seoul.

The Effect of Turbulence Penetration on the Thermal Stratification Phenomenon Caused by Coolant Leaking in a T-Branch of Square Cross-Section

  • Choi, Young-Don;Hong, Seok-Woo;Park, Min-Soo
    • International Journal of Air-Conditioning and Refrigeration
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    • v.11 no.2
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    • pp.51-60
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    • 2003
  • In the nuclear power plant, emergency core coolant system (ECCS) is furnished at reactor coolant system (RCS) in order to cool down high temperature water in case of emergency. However, in this coolant system, thermal stratification phenomenon can occur due to coolant leaking in the check valve. The thermal stratification produces excessive thermal stresses at the pipe wall so as to yield thermal fatigue crack (TFC) accident. In the present study, effects of turbulence penetration on the thermal stratification into T-branches with square cross-section in the modeled ECCS are analysed numerically. Standard k-$\varepsilon$ model is employed to calculate the Reynolds stresses in momentum equations. Results show that the length and strength of thermal stratification are primarily affected by the leak flow rate of coolant and the Reynolds number of duct. Turbulence penetration into the T-branch of ECCS shows two counteracting effects on the thermal stratification. Heat transport by turbulence penetration from main duct to leaking flow region may enhance thermal stratification while the turbulent diffusion may weaken it.

40-TFLOPS artificial intelligence processor with function-safe programmable many-cores for ISO26262 ASIL-D

  • Han, Jinho;Choi, Minseok;Kwon, Youngsu
    • ETRI Journal
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    • v.42 no.4
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    • pp.468-479
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    • 2020
  • The proposed AI processor architecture has high throughput for accelerating the neural network and reduces the external memory bandwidth required for processing the neural network. For achieving high throughput, the proposed super thread core (STC) includes 128 × 128 nano cores operating at the clock frequency of 1.2 GHz. The function-safe architecture is proposed for a fault-tolerance system such as an electronics system for autonomous cars. The general-purpose processor (GPP) core is integrated with STC for controlling the STC and processing the AI algorithm. It has a self-recovering cache and dynamic lockstep function. The function-safe design has proved the fault performance has ASIL D of ISO26262 standard fault tolerance levels. Therefore, the entire AI processor is fabricated via the 28-nm CMOS process as a prototype chip. Its peak computing performance is 40 TFLOPS at 1.2 GHz with the supply voltage of 1.1 V. The measured energy efficiency is 1.3 TOPS/W. A GPP for control with a function-safe design can have ISO26262 ASIL-D with the single-point fault-tolerance rate of 99.64%.

Fabrication of 3-Dimensional Microstructures using Digital Micromirror Device (Digital Micromirror Device 를 이용한 3차원 마이크로구조물 제작)

  • Choi, Jae-Won;Ha, Young-Myoung;Choi, Kyung-Hyun;Lee, Seok-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.11 s.188
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    • pp.116-125
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    • 2006
  • MEMS and LIGA technologies have been used for fabricating microstructures, but their shape is not 3D because of difficulty for preparation of many masks. To fabricate 3D microstructures, microstereolithography technology based on Digital Micromirror Device($DMD^{TM}$) was introduced. It has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D parts are fabricated by layer-by-layer according to 2D section sliced from STL file. The UV light source is illuminated to DMD which makes bitmap images of 2D section, and they are transferred and focused on resin surface. In this paper, we addressed optical design of microstereolithography system in consideration of light path according to DMD operation and image-forming on the resin surface using optical design program. To verify the performance of implemented microstereolithography system, 3D microstructures with complexity and high aspect ratio were fabricated.

Sensitivity of Dimensional Changes to Interfacial Friction over the Definite Range of Friction Factor in Ring Compression Test (링 압축시험에서 마찰인자 구간별 치수 변화의 민감도)

  • Lim, J.Y.;Noh, J.H.;Hwang, B.B.
    • Transactions of Materials Processing
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    • v.19 no.8
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    • pp.494-501
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    • 2010
  • The main objective of this study is to examine the sensitivity of calibration curves of FEA of ring compression test to frictional shear factor. Ring compression test has been investigated by measuring dimensional changes at different positions of ring specimen and they include the changes in internal diameter at the middle and top section of the specimen, outer diameter at the middle and top section, surface expansion at the top surface, respectively. Initial ring geometries employed in analysis maintain a fixed ratio of 6 : 3 : 2, i.e. outer diameter : inner diameter : thickness of the ring specimen, which is generally known as 'standard' specimen. A rigid plastic material for different work-hardening characteristics has been modeled for simulations using rigid-plastic finite element code. Analyses have been performed within a definite range of friction as well as over whole range of friction to show different sensitivities to the interfacial friction for different ranges of friction. The results of investigation in this study have been summarized in terms of a dimensionless gradient. It has been known from the results that the dimensional changes at different positions of ring specimen show different linearity and sensitivity to the frictional condition on the contact surface.