• Horticultural Science & Technology
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• v.35 no.3
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• pp.373-380
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• 2017

Amaryllis ($Hippeastrum{\times}johnsonii$) is commonly propagated by three methods: seeds, offset bulblets, and twin scaling. Since the number and size of bulblets produced by these methods are low, we conducted an experiment to evaluate different bulb cutting methods for propagation. For this purpose, bulbs (circumference of 30 - 35 cm) were sectioned or notched into 8, 12, or 16 segments or twin-scaled into 48, 72, or 96 segments for bulblet formation. Our results show that the largest number of bulblets was produced by the twin scaling method, but they take longer to grow to a final, commercial size. Sectioning and notching resulted in larger, but fewer bulblets than twin-scaling. Compared to notching, sectioning provided more space for the bulblets to grow, and is therefore the recommended method. While increasing the number of sections cut from a single bulb resulted in a larger number of bulblets, the diameter of the bulblets decreased. Therefore, sectioning the bulb into 8 segments was the best method for producing an acceptable number of vigorous bulblets.

• Kyungpook Mathematical Journal
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• v.56 no.4
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• pp.1191-1205
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• 2016

The emergence of various Internet worms, including the stand-alone Code Red worm that caused a distributed denial of service (DDoS), has prompted many studies on their propagation speed to minimize potential damages. Many studies, however, assume the same probabilities for initially infected nodes to infect each node during their propagation, which do not reflect accurate Internet worm propagation modelling. Thus, this paper analyzes how Internet worm propagation speed varies according to the number of vulnerable hosts directly connected to infected hosts as well as the link costs between infected and vulnerable hosts. A mathematical model based on centrality theory is proposed to analyze and simulate the effects of degree centrality values and closeness centrality values representing the connectivity of nodes in a large-scale network environment on Internet worm propagation speed.

• Bulletin of the Society of Naval Architects of Korea
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• v.12 no.2
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• pp.43-58
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• 1975

There are many reports on fatigue crack of metallic materials but most of them relate crack propagation rate to stress intensity factor. The problem of crack propagation is not yet clarified, especially the bridge between micro and macro phenomena In this experiment rotating bending fatigue tests have been carried out with smoothed specimen of rolled steel plates including 0.2% carbon under application of three stress conditions to investigate the slip band and the crack propagation behaviour. The results obtained are as follows; 1) The length of cracks which have grown at initial crack tips can be expressed as follows; $l=Ae^{BNr}$(A,B: constant, $N_r$: cycle ratio) $\frac{dl}{dN}=\frac{AB}{N_f}{\cdot}e^{BNr}$($N_f$:fatigue life) 2) The ratio of slipped grain number to total grain number is $S_f=7{\sigma}-5.6$-5.6{\sigma}_c$($\sigma$: stress amplitude) (${\sigma}_c$: fatigue limit) 3) When the fatigue process transfers from Stage I to Stage II, the crack which propagates into specimen changes its direction from that of the maximum shear stress to the direction of perpendicular to principal stress and this is same in the circumferential direction of specimen. the crack propagation behaviors of both sides of a crack are different each other when they approach to the grain boundary.

• Structural Engineering and Mechanics
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• v.70 no.1
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• pp.55-66
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• 2019

This work deals with the size-dependent wave propagation analysis of functionally graded (FG) anisotropic nanoplates based on a nonlocal strain gradient refined plate model. The present model incorporates two scale coefficients to examine wave dispersion relations more accurately. Material properties of FG anisotropic nanoplates are exponentially varying in the z-direction. In order to solve the governing equations for bulk waves, an analytical method is performed and wave frequencies and phase velocities are obtained as a function of wave number. The influences of several important parameters such as material graduation exponent, geometry, Winkler-Pasternak foundation parameters and wave number on the wave propagation of FG anisotropic nanoplates resting on the elastic foundation are investigated and discussed in detail. It is concluded that these parameters play significant roles on the wave propagation behavior of the nanoplates. From the best knowledge of authors, it is the first time that FG nanoplate made of anisotropic materials is investigated, so, presented numerical results can serve as benchmarks for future analysis of such structures.

• Journal of Information Processing Systems
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• v.16 no.3
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• pp.699-717
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• 2020

Propagation time on permissionless blockchain plays a significant role in terms of stability and performance in the decentralized systems. A large number of activities are disseminated to the whole nodes in the decentralized peer-to-peer network, thus causing propagation delay. The stability of the system is our concern in the first place. The propagation delay opens up opportunities for attackers to apply their protocol. Either by accelerating or decelerating the propagation time directly without proper calculation, it brings numerous negative impacts to the entire blockchain system. In this paper, we thoroughly review and elaborate on several parameters related to the propagation time in such a system. We describe our findings in terms of data communication, transaction propagation, and the possibility of an interference attack that caused an extra propagation time. Furthermore, we present the influence of block size, consensus, and blockchain scalability, including the relation of parameters. In the last session, we remark several points associated with the propagation time and use cases to avoid dilemmas in the light of the experiments and literary works.

• The Journal of Information Technology
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• v.2 no.2
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• pp.145-161
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• 1999

This paper proposes a high speed back propagation neural networks which uses the residue number system. making the high speed operation possible without carry propagation Consisting of MAC(Multiplication and Accumulation) operator unit using Residue number system and sigmoid function operator unit using Mixed Residue Conversion is designed, The Designed circuits are descripted by VHDL and synthesized by Compass tools. Result of simulations shows that critical path delay time is about 19nsec and the size can be reduced to 40% compared to the neural networks implemented by the real number operation unit. The proposed design circuits can be implemented in parallel distributed processing system with desired real time processing.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.1
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• pp.36-43
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• 2015

Since the crack generation and its propagation caused by welding defects is one of the main hull damage patterns, the simulation of crack propagation process has an important significance for ship safety. Based on interface element method, a finite element model to simulate crack propagation is studied in the paper. A Lennard-Jones type potential function is employed to define potential energy of the interface element. Tensile tests of steel flat plates with initial central crack are carried out. Surface energy density and spring critical stress that are suitable for the simulation of crack propagation are determined by comparing numerical calculation and tests results. Based on a large number of simulation results, the curve of simulation correction parameter plotted against the crack length is calculated.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.5
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• pp.81-87
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• 1994

This paper proposes a divider structure that combines a carry-propagation-free division algorithm using RSD number system and a self-timed ring structure. The self-timed ring structure enables the divider to compute at a speed comparable to that of combinational array dividers with less silicon area. By exploiting the carry-propagation-free division algorithm, we can achieve further reduction of silicon area and computation time. The algorithm and structure of the proposed divider have been successfully verified through VHDL modeling and simulation. Preliminary experimental results show the effectiveness of the algorithm and structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.141-145
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• 1998

This paper CMOS full adder design method based on carry-propagation-free addition trees and a circuit technique, so called multiple-valued current-mode (MVCM) circuits. The carry-paopagation-free addition method uses a redundant digit sets called redundant positive-digit number representations. The carry-propagation-free addition is by three steps, and the adder can be designed directly and efficiently from the algorithm using MVCM circuit. We demonstrate the effectiveness of the proposed method through simulation(SPICE).

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.1-8
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• 2007

Although the Java bytecode has numerous advantages. there ate also shortcomings such as slow execution speed and difficulty in analysis. Therefore. in order for the Java class file to be effectively executed under the execution environment such as the network, it is necessary to convert it into optimized code. We implements CTOC. CTOC generated CFG using the existing bytecode then created the SSA Form for analysis and optimization. However. due to insertion or the ${\phi}$-function in the process of conversion into the SSA Form, the number of nodes increased. As a means of reducing the number of nodes, we performed copy propagation, which is an optimization method applicable to the SSA form. Copy propagation is the process of a value of a variable being topied to another variable. There are cases where conversion due to copy propagation alone does not yield significant effects. However, when variables are not used in the later optimization stages, copy propagation provides a means for eliminating the copy statement for the corresponding variable, making it an important step. This paper shows the copy propagation to obtain a more optimized code in SSA Form.