• Journal of applied mathematics & informatics
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• v.7 no.3
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• pp.861-873
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• 2000

Rate-based flow control plays an important role for efficient traffic management of Available Bit Rate(ABR) services. We deal with the problem of the buffer dimension for rate-based ABR control. In this paper, we analyze the Allowed Cell Rate(ACR) of a source and the queue size in a steady state. First, we investigate the effect of the number of active sources on the behavior of the ACR and the maximum queue size. Reflecting the effect of this real scenes, we determine the optimal buffer size and buffer threshold. Furthermore, our analytic results are compared with the case when the effect of the number of active sources is disregarded.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.243-251
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• 2012

Under the power-based capture model, a transmission is successfully received at the destination, even in the presence of other transmissions and background noise, if the received signal-to-interference-plus-noise ratio exceeds a capture threshold. We evaluate the spectral efficiency of simple multi-user channels by combining the basic capture model with a communication-theoretic model. The result is a more refined capture model that incorporates key system design parameters (such as achievable bit rate, target bit error rate, channel bandwidth, and modulation signal constellations) that are absent from the basic capture model. The relationships among these parameters can serve as a tool for optimizing the network performance.

• Transactions of Materials Processing
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• v.19 no.7
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• pp.393-398
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• 2010

This paper investigates the effect of material properties on the formability of sheet metals based on the Marciniak-Kuczynski model (M-K model). The hardening behavior of the material is modeled as the Hollomon model with the strain rate effect. The yield surfaces are constructed with Hosford79 yield function. The material properties considered in this study include the R-value, the strain hardening exponent, the strain rate hardening exponent, and the crystal structure of the material. The effect of the crystal structure on formability is roughly expressed as the change of the yield surface by varying the value of the exponent in Hosford79 yield function. Results show that the R-value affects neither the magnitude nor the shape of right hand side of forming limit diagrams (FLDs). Higher strain hardening exponent and higher strain rate hardening exponent improve the formability of sheet metals because they stabilize the forming processes.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.177-184
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• 2005

Recently, the engineering designer of injection mould has become more and more dependent on the CAE. In the design factors of injection mould, the shrinkage rate should be considered as one of the important performances to produce the reliable products. therefore the shrinkage rate can be mostly calculated by the MoldFlow and Pro-engineering. in the design process. However it is not easy to predict the shrinkage rate of a plastic injection mold in its design process because the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models, DACE model, based on the Kriging in order to optimize the shrinkage rate of electric microwave oven window is used in lieu of the original models, facilitating design optimization.

• Journal of Surface Science and Engineering
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• v.32 no.2
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• pp.83-92
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• 1999

GaN etching was performed using planar inductively coupled $Cl_2$-based plasmas and the effects of main process parameters on the characteristics of the plasmas and their relations to GaN etch rates were studied. Also, the GaN etch mechanism was investigated using a Langmuir probe and optical emission spectroscopy (OES) during the etching, and X-ray photoelectron spectroscopy (XPS) of the etched surfaces. The GaN etch rates increased with the increase of chlorine radical density and ion energy, and a vertical etch profile haying the etch rate close to 4000 $\AA$/min could be obtained. The addition of 10% Ar to $Cl_2$ gas increased the GaN etch rate and the addition of Ar (more than 20%) and HBr generally reduced the GaN etch rate. The GaN etch rate appeared to be more affected by the chemical reaction between Cl radicals and GaN compared to the physical sputtering itself under the sufficient ion bombardments to break GaN bonds.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.304-305
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• 2018

Development of waterproof methods and materials resulted in the huge changes in waterproof construction materials. In consequence, the construction-standard-production-rate underwent overall revision in 2018. Especially, from the development of the specification standard and construction methods, the waterproof construction which had lower applicability in the existing construction production rate was revised. The construction methods which did not have applicability were removed. In addition, as there was a material difference based on parts, the constructionstandard-production-rate was revised by distinguishing vertical part and floor. Furthermore, by suggesting more clear work extent, the practicability in creating the standard for calculation of the estimated price in the construction field will increase.

• Hwankyungkyoyuk
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• v.17 no.1
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• pp.133-143
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• 2004

This study aims to explore the ways in spreading and maturing of environmental Education(EE) in secondary school. To deal with this issue, researchers investigate the actual conditions of EE and grope for the ways in spreading and maturing of EE. According to investigation, the selecting rate of environment subject in secondary school is about 3%(compared selecting rate of other subject matters) in 2003. Based on the result, this study suggests followings. First, sequencing strategy of EE curriculum will be expected very efficaciously. Secondly, there is need to empasize daily experiences of EE beyond the formal subject matter. Thirdly and ultimately, thers is need to reform school curriculum centered EE. Moreover, there is need to empasize teacher education for the environment not only pre service but also in-service teacher training.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.65-76
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• 2014

In this article, a new model based on Lomax distribution is introduced. This new model is both useful and practical in areas such as economic, reliability and life testing. Some statistical properties of this model are presented including moments, hazard rate, reversed hazard rate, mean residual life and mean inactivity time functions, among others. It is also shown that the distributions of the new model are ordered with respect to the strongest likelihood ratio ordering. The method of moment and maximum likelihood estimation are used to estimates the unknown parameters. Simulation is utilized to calculate the unknown shape parameter and to study its properties. Finally, to illustrate the concepts, the appropriateness of the new model for real data sets are included.

• Asia pacific journal of information systems
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• v.4 no.1
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• pp.3-31
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• 1994

Potential employers considering locations for production or service facilities typically equire detailed advance knowledge of the wages they will be expected to offer for workers in various occupational categories. The State of Missouri s Department of Labor and Industrial Relations is often contacted by organizations requesting such information. The current wage rate survey approach, initiated in 1988, allows the Department to predict an appropriate wage rate for a given occupation in certain counties, adjusted for changes in the Consumer Price Index (CPI). However, both Department employees and firms have indicated that improved prediction responsiveness and accuracy are desirable. A major deficiency of the current approach is its inability to predict wages for unsurveyed counties. This paper describes a knowledge-based system (KBS), currently in the prototype testing stage, that is expected to supplement the wage rate survey in the near future.

• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.214-222
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• 2008

Bode principle is applied to carry out traffic control for rate based ATM network, which guarantees the higher buffer utilization, buffer overflow-free, and well utilization of bandwidth. The principle confirms the relationship between the threshold of buffer queue and the network bandwidth, as well as the relationship between the threshold of buffer and source input rate. Theoretic warrant of the buffer threshold is proposed. The reference range of source input rate is provided in theory, which makes the source end respond to the change of network state rapidly and dynamically, and then the effect of time delay to the traffic control is avoided. Simulation results show that the better steady and dynamic performances of networks are obtained by Bode principle.