• Journal of the Korean Wood Science and Technology
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• 제18권2호
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• pp.67-78
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• 1990

This study was performed to determine the characteristics of physical and mechanical properties of domestic wood based materials; plywood, particleboard, medium density fiberboard. Main items of tested properties were panel size, moisture content, water absorption, linear expansion and thickness swelling, glue bond shear strength, bending properties(stress at proportional limit, modulus of rupture. modulus of elasticity), tensile strength, screw holding strength, and internal bond as neccessary. the results were discussed mainly with Korean Standards. The obtained conclusions are as follows; 1. Length and width of 3mm thin plywood(3-ply) and 12mm thick plywood(7-ply) were satished with KS-standard, but thicknesses of these panels were not- passed tolerance limit except one of eight makers. 2. Length and width of particleboard and medium density fiberboard were greater than the tolerance limit value of KS standard, but the thicknesses of these panels were passed this value. 3. Moisture contents of 12mm thick and 3mm thin plywood were satisfied with KS-standard except one mill made 3mm thin plywood. 4. Moisture absortion of plywood was not passed tolerance limit of KS-standard but particleboard was satisfied with this standard value. 5. Dry and wet shear strengths in glue bond of 3mm thin plywood were not reached to KS-standard, but those of 12mm thick plywood were sufficiently satisfied with KS standrad. 6. Modulus of ruptures, parallel to grain and perpendicular to grain of plywood, and particleboard and medium density fiberboard were satisfied with KS-standard. 7. Tensile strengths, parallel to grain and perpendicular to grain of plywood were satisfied with allowance stress of US product standard PS 1-74. 8. Screw holding strength of particleboard was not reached to KS standard, but internal bond was satisfied with KS standard.

• 한국지능시스템학회논문지
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• 제22권1호
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• pp.49-55
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• 2012

전역 클럭 없이 외부 입력에 따라서 값이 변하는 비동기 카운터는 우주용 메모리 등 현대 디지털 시스템에서 널리 사용된다. 본 논문에서는 우주 방사능 누적에 기인하는 크리티컬 레이스 고장이 존재하는 비동기 카운터를 위한 고장 극복 기법을 제안한다. 크리티컬 레이스는 비동기 디지털 회로 설계 과정에서 발생하는 대표적인 고장으로서 회로의 다음 안정 상태가 고정되지 않고 여러 값 중 하나로 나오는 비결정적인 특성을 보인다. 이번 연구에서는 비동기 순차 머신에 대한 교정 제어 기법을 이용하여 크리티컬 레이스를 극복할 수 있는 상태 피드백 제어기의 설계 과정을 제시한다. 또한 비동기 카운터 교정 제어 시스템을 VHDL 코드로 구현하고 실험을 통하여 제안된 제어 시스템이 크리티컬 레이스 고장을 극복하는 과정을 예시한다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2003년도 제10차 국제학술회의 및 추계정기 학술발표회
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• pp.43-43
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• 2003

Multiple regression equations (Rehman et al. 2000) have been developed to predict the salinity tolerance of Acacia seeds, expressed as the I$\sub$50/ (the concentration of NaCl required to reduce final germination to 50% of the control value in DW). Accurate predictions can be made using one or more chemical and biological seed parameters. In this study the theoretical effect of varying final germination percentage in distilled water, germination rate in distilled water. (Rate), Ca$\^$2+/ or K$\^$+/ contents and their ratios, as independent factors or related factors, on the predicted salinity tolerance (I$\sub$50/) of Acacia species was investigated. Simulation of the effects of changing final germination, rate, calcium and potassium suggest the possibility of practical application of these results to modify the salinity tolerance of seeds. The predicted I$\sub$50/ increased with increasing final germination. Similarly, the higher the rate of germination, the higher the predicted salt tolerance of Acacia species. The Ca$\^$2+/ content of seeds was found to be positively correlated with I$\sub$50/. Species with higher Ca$\^$2+/ contents had a higher I$\sub$50/. This suggests that I$\sub$50/ might be increased by increasing the Ca$\^$2+/ contents of seeds by pretreatment with calcium salts or by supplying these to the mother plants.

• 원예과학기술지
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• 제32권2호
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• pp.142-148
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• 2014

Effect of silicon (Si) nutrition on growth and temperature stress tolerance of Nephrolepis exaltata 'Corditas' grown in a soilless substrate was examined. In vitro-grown acclimatized plantlets were transplanted into the pots containing a coir-based substrate. A nutrient solution containing 0, 50, or $100mg{\cdot}L^{-1}$ Si was supplied through a drip-irrigation system. After 5 months of cultiv ation, S i-treated and -untreated p lants were grown at 10, 25, or $40{\pm}1^{\circ}C$ under a 12 h photoperiod with $530{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and 60% RH. After 7 days, chlorophyll content and chlorophyll fluorescence parameters were measured. Silicon nutrition had a negative effect on growth characteristics of N. exaltata 'Corditas'. However, Si-treated plants had more tolerance to temperature stress than the control plants. The Fv/Fm value was not significantly different when the plants were exposed to $25^{\circ}C$. However, significant difference in Fv/Fm was recorded when plants were exposed to 10 or $40^{\circ}C$. Thus, Fv/Fm could be used as an indicator of low and high temperature tolerance in ferns. The present study also suggests that application of Si may be used to enhance temperature tolerance of ferns.

• 품질경영학회지
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• 제24권1호
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• pp.50-60
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• 1996

Though the quality characteristics within a specified tolerance are equally desired quality there is a difference in conformance between a specification limit and a target value. In this paper we propose a measure of process capability that takes into account the degree of conformance to a target value as well as the process variation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.959-964
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• 1993

We developed fault diagnosis fuzzy expert system for ACS(Advanced Control System). ACS is a DCS(Distributed Control System) with advanced control algorithm fault tolerance capabilities, fault diagnosis functions, and so on. Fuzzy expert system developed for an ACS in this paper gives an operator alarm signal depending on the state of process value and manipulated value, and the cause of alarm in real time. Simple experiment result with several rules for the-fault-diagnosis of drum level loop in Seoul-Power-Plant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1205-1208
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• 1996

This paper proposes balanced model reduction of non-minimum phase plant. The algorithm presented in this paper is to convert high-order non-minimum phase plant into low-oder minimum phase plant using balanced model reduction. Balanced model reduction requires the error bound that Hankel singular value produces. This algorithm shows the tolerance that admits the method of this paper.

• 제어로봇시스템학회지
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• 제10권3호
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• pp.21-26
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• 2004

Structured singular value (SSV)는 robust stability와 robust performance를 매우 엄밀하게 다루기 위해 고안되었다 (Doyle, 1982; Safonov, 1982). 이 엄밀성으로 제어시스템의 설계 및 분석에 광범위하게 사용되고 있다. 강건제어의 단초를 이루었으며 loop failure tolerance, decentralized integral controllability (Campo and Morari. 1994), D-stability (Lee and Edgar, 2001) 등에 SSY가 사용되고 있다. SSV의 중요성이 알려짐에 따라 이것에 관한 많은 연구가 있었다(Fan et at., 1991 ; Pacltard and Pander, 1993), 그러나 이 값의 계산은 매우 어려운 NP-hard인 것으로 판명되었으며 (Braatz et al.. 1994). 실수 불확실 변수에 대한 SSV의 경우 원하는 오차범위 내로 근사 값을 구하는 것도 마찬가지 인 것으로 밝혀졌다(Fu, 1997).(중략)

• 한국지반공학회지:지반
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• 제11권2호
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• pp.99-106
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• 1995

기본적인 성질 평가와 많은 실내실험을 통해 우리나라에서 부산되는 석탄재는 이제 실용화 단계에 있지만, 가장 문제 제기가 되고 있는 부분은 환경적 특성 검토이다. 본 연구에서는 석탄재 발생량의 대부분을 차지하고 있는, 역학적 특성이 열악한 fly ash.를 대상으로 우리나라 환경기 준에 의하여 폐기물 분류를 분석 확인하구 매립 및 대규모 토공재 등 건설재료로 처리 또는 사용하였을 시 오염물질 배출허용기준에 의한 문제점이 있는가를 검토하기 위하여 회분식 용출시험에 의하여 수소이온농도 및 오염물질 함유량을 조사.분석해 보았다. 그 결과 fly ash는 일반폐기물로 분류됨을 확인하였고, fly ash의 PH는 오염 물질 배출허용 기준치보다 알칼리성을 강하게 띠고 있어 문제가 되고 있으나 이는 산성화된 토양을 중성화하는 토량개량재로서 fly ash의 역할을 기대할 수 있으며, 그 외에는 오염물질 배출허용 기준치에 훨씬 못 미치는 것으로 나타나고 있다. 더구나 석탄재의 열악한 역학적 특성을 개량하기 위하여 사용되는 정도의 소량의 첨가제(시멘트 또는 석회 등)에 의하여 강도 및 내구성 증가, 투수성 억제는 물론 문제가 되는 수소이온농도가 오염물질 배출허용기준(pH 5.8~8.6) 이하로 낮아져, 석탄재의 건설재료로서의 활용에 있어 환경적인 문제의 여지는 없을 것으로 여겨진다.

• 산업경영시스템학회지
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• 제41권4호
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• pp.91-100
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• 2018

The setting of values on door hinge mounting compensation for door assembly tolerance is a constant quality issue in vehicle production. Generally, heuristic methods are used in satisfying appropriate door gap and level difference, flushness to improve quality. However, these methods are influenced by the engineer's skills and working environment and result an increasement of development costs. In order to solve these problems, the system which suggests hinge mounting compensation value using CAE (Computer Aided Engineering) analysis is proposed in this study. A structural analysis model was constructed to predict the door gap and level difference, flushness through CAE based on CAD (Computer Aided Design) data. The deformations of 6-degrees of freedom which can occur in real vehicle doors was considered using a stiffness model which utilize an analysis model. The analysis model was verified using 3D scanning of real vehicle door hinge deformation. Then, system model which applying the structural analysis model suggested the final adjustment amount of the hinge mounting to obtain the target door gap and the level difference by inputting the measured value. The proposed system was validated using the simulation and showed a reliability in vehicle hinge mounting compensation process. This study suggests the possibility of using the CAE analysis for setting values of hinge mounting compensation in actual vehicle production.