• Structural Engineering and Mechanics
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• 제26권1호
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• pp.15-30
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• 2007

In the paper, one focuses on the problem of duality in non-linear programming, applied to the solution of no-tension problems by means of Limit Analysis (LA) theorems for Not Resisting Tension (NRT) models. In details, one demonstrates that, starting from the application of the duality theory to the non-linear program defined by the static theorem approach for a discrete NRT model, this procedure results in the definition of a dual problem that has a significant physical meaning: the formulation of the kinematic theorem.

• Biomolecules & Therapeutics
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• 제5권1호
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• pp.82-86
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• 1997

Pharmacokinetics of a new capsaicin analog, DA-5018 were evaluated after a subcutaneous injection or topical application of $[^{14}C]$--labelled or unlabelled DA-5018 to rats and rabbits. After subcutaneous injection of $_{14}$c-labelled or unlabelled DA-5018, 0.5 mg/kg (equivalent to DA-5018) to rats, the plasma total activity peaked at 2 hr with the terminal half life of 5.34 hr, however, unlabelled-DA-5018 peaked at 1 hr with the terminal half life of 1.26 hr. Moreover, the AUC (0.726 versus 0.2337g hr/ml) and MRT (7.82 versus 3.55 hr) increased significantly based on total radioactivity compared with intact DA-5018. Above data indicated that DA-5018 is extensively metabolized in rats and the terminal half- life of the metabolite(5) had a longer half-life than that of DA-5018. The cumulative percentages of biliary excretion of dose after subcutaneous injection of $[^{14}C]$DA-5018 was 40.2%, however, the value was only 2.14% when unlabelled DA-5018 was injected. After topical application of 0.1% or 0.3% $_{14}$C-labelled or unlabelled DA-5018 cream, 500 mg/kg to rats, the plasma and tissue concentrations except applied skin were under the detection limit. After consecutive 7 days topical application of unlabelled DA-5018, 0.1% and 0.3% cream to rats, the plasma concentrations were also under the detection limit. But the urinary excretion of DA-5018 was significantly increased by repeated topical administration. After topical application of unlabelled DA-5018, 0.1% and 0.3% cream to rabbits, the plasma and urine concentrations were under the detection limit. Above data indicated that the skin permeation of DA-5018 was lower and the metabolism of DA-5018 was higher in rabbits than that in rats.

• 자동차안전학회지
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• 제7권4호
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• pp.26-30
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• 2015

Exceeding the speed limit during vehicle driving is a key factor in the severity of lots of road accidents, and SLIF(Speed Limit Information Function) application is in the initial phase in Korea. SLIF helps the drivers to observe a speed limit when they are driving by providing alert and informing the current limit speed information based on external data using camera and/or digital map, for that reason, environmental conditions could be causes of SLIF malfunctions. In this study, design adequacy analysis of SLIF in respect of false recognition as the Korea traffic environment has been performed. As tentative results, road conditions and structure of speed limit sign as well as system performance often caused misrecognition.

• Structural Engineering and Mechanics
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• 제50권2호
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• pp.201-214
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• 2014

Due to the confinement effects, Steel-Straps Tensioning Technique (SSTT) can significantly enhance the strength and ductility of high-strength concrete (HSC) members (Moghaddam et al. 2008). However, the enhancement especially in strength may result in slender member and more susceptible to instability (Jiang and Teng 2012a). This instability is particularly significant in HSC member as it inherent the brittle nature of the material (Galano et al. 2008). The current slenderness limit expression used in the design is mainly derived from the experiment and analysis results based on Normal strength concrete (NSC) column and therefore the direct application of these slenderness limit expressions to the HSC column is being questioned. Besides, a particular slenderness limit for the SSTT-confined HSC column which incorporated the pre-tensioned force and multilayers effects is not yet available. Hence, an analytical study was carried out in the view of developing a simple equation in order to determine the slenderness limit for HSC column confined with SSTT. Based on the analytical results, it was concluded that the existing slenderness limit expressions used in the design are appropriate for neither HSC columns nor SSTT-confined HSC columns. In this paper, a slenderness limit expression which has incorporated the SSTT-confinement effects is proposed. The proposed expression can also be applied to unconfined HSC columns.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.28-35
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• 2005

It is now well recognized that the ultimate limit state approach is a much better basis for design and strength assessment of ships and offshore structures since it is difficult to determine the realistic margin of safety using the traditional allowable working stress approach on the basis of linear elastic method solutions together with buckling strengthchecks adjusted by a simple plasticity correction. This paper outlines ALPS theory for ultimate limit state assessment of ship structures. ALPS is a computer software which stands for nonlinear Analysis of Large Plated Structures. Application examples of ALPS program to ultimate limit state assessment of plates, stiffened panels and ship hull girders are presented. A benchmark study is made by a comparison with the ALPS solutions with other methods including class rule formulae, nonlinear finite element methods and experimental results. Future trends on ultimate limit state assessment of ship structures are addresse[1]

• 산업기술연구
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• 제18권
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• pp.203-208
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• 1998

Fatigue tests were performed to examine the 4 parameter method for specimens prepared by various heat treatment which resulted in different mechanical properties. Obtained main results are as follows. (1) Samples treated by austempering did not show the expected improvement of fatigue limit although hardness and strength increased. This is attributed to the fact that defect sensitivities of materials increase as increasing of hardness and tensile strength, it is also shown that the graphites acting as stress concentration place become larger by austempering heat treatment than by normal annealing. (2) It is very reasonable to predict the fatigue limit of ductile irons with 4 parameter method based on ${\sigma}_{TS}$, $H_v$, ${\Delta}K_{th}$ and ${\sqrt{area}}_{max}$. (3) The half-austempering treatment appeared to be more useful than the full-austempering method to improve the fatigue limit in the spheroidal graphite cast iron with multi defective material.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.50-52
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• 2008

We have limited the transfer power to capital area below a certain level which is called "The Capital Area Transfer Power Limit", and calculated on every Thursday for the application next week. This level is very important in our network operation, because if this level is not set properly, our power network can be fallen under great danger in case of a fault among the transfer power line. But the calculation procedure for the limit level is so complicated and iterative that it mace us spend much time and do much work. So, when a sudden trip of the related facility to the limit level we can't recalculate the limit level fast enough. And this can drop our network reliability below our standards, therefore our network can be dangerous. To avoid this kind of problems, we have figured out a method to calculate simply the limit level. That method uses the index related to the level. We think this method can make short of the calculation procedures for the level. This paper deals with the simplified method for the calculation of the level limit.

• 소성∙가공
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• 제14권6호
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• pp.527-532
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• 2005

Among the failure modes which can occur in tube hydroforming such as wrinkling, bursting or buckling, the bursting by local instability under excessive tensile stresses is irrecoverable phenomenon. Thus, the accurate prediction of bursting condition plays an important role in producing the successfully hydroformed part without any defects. As the classical forming limit criteria, strain-based forming limit diagram (FLD) has widely used to predict the failure in sheet metal forming. However, it is known that the FLD is extremely dependant on strain path throughout the forming process. Furthermore, The application of FLD to hydroforming process, where strain path is no longer linear throughout forming process, may lead to misunderstanding for fracture initiation. In this work, stress-based forming limit diagram (FLSD), which is strain path-independent and more general, was applied to prediction of forming limit in tube hydroforming. Combined with the analytical FLSD determined from plastic instability theory, finite element analyses were carried out to find out the state of stresses during hydroforming operation, and then FLSD is utilized as forming limit criterion. In addition, the approach is verified by a series of bulge tests in view of bursting pressure and shows a good agreement. Consequently, it is shown that the approach proposed in this paper will provide a feasible method to satisfy the increasing practical demands for judging the forming severity in hydroforming processes.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.92-96
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• 2005

Among the failure modes which can be occurred in tube hydroforming such as wrinkling, bursting or buckling, the bursting by local instability under excessive tensile stresses is irrecoverable phenomenon. Thus, the accurate prediction of bursting condition plays an important role in producing the successfully hydroformed part without any defects. As the classical forming limit criteria, strain-based forming limit diagram has widely used to predict the failure in sheet metal forming. However, it is known that the FLD is extremely dependant on strain path throughout the forming process. Furthermore, the path-dependent limitation of FLD makes the application to hydroforming process, where strain path is no longer linear throughout forming process, more careful. In this work, stress-based forming limit diagram (FLSD), which is strain path-independent and more general, was applied to prediction of forming limit in tube hydroforming. Combined with the analytical FLSD determined from plastic instability theory, finite element analyses were carried out to find out Ihe state of stresses during hydroforming operation, and then FLSD is utilized as forming limit criterion. In addition, the approach is verified with a series of bulge tests in view of bursting pressure and shows a good agreement. Consequently, it is shown that the approach proposed in this paper will provide a feasible method to satisfy the increasing practical demands for judging the farming severity in hydroforming processes.

• IEIE Transactions on Smart Processing and Computing
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• 제4권4호
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• pp.237-250
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• 2015

This paper describes a hardware-oriented algorithm and its conceptual implementation in a real-time speed limit traffic sign detection system on an automotive-oriented field-programmable gate array (FPGA). It solves the training and color dependence problems found in other research, which saw reduced recognition accuracy under unlearned conditions when color has changed. The algorithm is applicable to various platforms, such as color or grayscale cameras, high-resolution (4K) or low-resolution (VGA) cameras, and high-end or low-end FPGAs. It is also robust under various conditions, such as daytime, night time, and on rainy nights, and is adaptable to various countries' speed limit traffic sign systems. The speed limit traffic sign candidates on each grayscale video frame are detected through two simple computational stages using global luminosity and local pixel direction. Pipeline implementation using results-sharing on overlap, application of a RAM-based shift register, and optimization of scan window sizes results in a small but high-performance implementation. The proposed system matches the processing speed requirement for a 60 fps system. The speed limit traffic sign recognition system achieves better than 98% accuracy in detection and recognition, even under difficult conditions such as rainy nights, and is implementable on the low-end, low-cost Xilinx Zynq automotive Z7020 FPGA.