• Bulletin of the Korean Chemical Society
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• 제25권11호
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• pp.1621-1622
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• 2004

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2397-2400
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• 2012

• 한국정보시스템학회지:정보시스템연구
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• 제15권4호
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• pp.211-224
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• 2006

This study investigates the application of data mining techniques such as artificial neural networks, rough sets, and induction teaming to the intrusion detection systems. To maximize the effectiveness of data mining for intrusion detection systems, we introduced the asymmetric costs with false positive errors and false negative errors. And we present a method for intrusion detection systems to utilize the asymmetric costs of errors in data mining. The results of our empirical experiment show our intrusion detection model provides high accuracy in intrusion detection. In addition the approach using the asymmetric costs of errors in rough sets and neural networks is effective according to the change of threshold value. We found the threshold has most important role of intrusion detection model for decreasing the costs, which result from false negative errors.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.357-367
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• 2021

In general, common cause failures (CCFs) have been modeled with the assumption that components within the same group are symmetric. This assumption reduces the number of parameters required for the CCF probability estimation and allows us to use a parametric model, such as the alpha factor model. Although there are various asymmetric conditions in nuclear power plants (NPPs) to be addressed, the traditional CCF models are limited to symmetric conditions. Therefore, this paper proposes the copulabased CCF model to deal with asymmetric as well as symmetric CCFs. Once a joint distribution between the components is constructed using copulas, the proposed model is able to provide the probability of common cause basic events (CCBEs) by formulating a system of equations without symmetry assumptions. In addition, Bayesian inferences for the parameters of the marginal and copula distributions are introduced and Markov Chain Monte Carlo (MCMC) algorithms are employed to sample from the posterior distribution. Three example cases using simulated data, including asymmetry conditions in total failure probabilities and/or dependencies, are illustrated. Consequently, the copula-based CCF model provides appropriate estimates of CCFs for asymmetric conditions. This paper also discusses the limitations and notes on the proposed method.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1825-1826
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• 2012

• Journal of Power Electronics
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• 제17권1호
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• pp.222-231
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• 2017

In this paper, a new architecture for a cost-effective power conditioning systems (PCS) using a single-sourced asymmetric cascaded H-bridge multilevel inverter (MLI) for photovoltaic (PV) applications is proposed. The asymmetric MLI topology has a reduced number of parts compared to the symmetrical type for the same number of voltage level. However, the modulation index threshold related to the drop in the number of levels of the inverter output is higher than that of the symmetrical MLI. This problem results in a modulation index limitation which is relatively higher than that of the symmetrical MLI. Hence, an extra voltage pre-regulator becomes a necessary component in the PCS under a wide operating bias variation. In addition to pre-stage voltage regulation for the constant MLI dc-links, another auxiliary pre-regulator should provide isolation and voltage balance among the multiple H-bridge cells in the asymmetrical MLI as well as the symmetrical ones. The proposed PCS uses a single-ended DC-DC converter topology with a coupled inductor and charge-pump circuit to satisfy all of the aforementioned requirements. Since the proposed integrated-type voltage pre-regulator circuit uses only a single MOSFET switch and a single magnetic component, the size and cost of the PCS is an optimal trade-off. In addition, the voltage balance between the separate H-bridge cells is automatically maintained by the number of turns in the coupled inductor transformer regardless of the duty cycle, which eliminates the need for an extra voltage regulator for the auxiliary H-bridge in MLIs. The voltage balance is also maintained under the discontinuous conduction mode (DCM). Thus, the PCS is also operational during light load conditions. The proposed architecture can apply the module-integrated converter (MIC) concept to perform distributed MPPT. The proposed architecture is analyzed and verified for a 7-level asymmetric MLI, using simulation results and a hardware implementation.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1280-1282
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• 2010

A new chiral catalyst was synthesized and found that it could catalyzed the asymmetric Michael reaction of ketones with nitroolefins smoothly at room temperature, giving the desired adducts in 71 - 92% yields with excellent diastereoselectivities and high enantioselectivities (up to 95% ee).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권4호
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• pp.376-384
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• 2009

In this article, we demonstrate that the asymmetric key-based architecture for securing wireless sensor networks recently introduced by Haque et al. is insecure under impersonation attack, since it does not provide authentication semantics. In addition, we show that, for the scheme to work correctly, the resulting key distribution construction should be symmetric and group-wise.

• 전자공학회논문지B
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• 제33B권6호
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• pp.54-63
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• 1996

We propose a 3rd order blind equalizer that incorporates a new transform method using either square root operation ($\sqrt{x]$) or reciprocal operation (1/x) in order to transform symmetric distribution of PAM signals at the transmitter, to asymmetric one. At the receiver, either the square operation or the reciprocal operation is needed to recover the asymmetrically transformed signals to the original ones after eualization. The reslts of the computer simulation, using the new method are better than the existing transform method using natural logarithm operation by the maximum of 8 dB in MSE. In addition, as the skewness of the asymmetrically transformed distribution has small values, the performances are improved.

• Communications for Statistical Applications and Methods
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• 제13권3호
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• pp.777-786
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• 2006

Two factorial designs with quantitative factors are called geometrically equivalent if the design matrix of one can be transformed into the design matrix of the other by row and column permutations, and reversal of symbol order in one or more columns. Clark and Dean (2001) gave a sufficient and necessary condition (which we call the 'gCD condition') for two symmetric factorial designs with quantitative factors to be geometrically equivalent. This condition is based on the absolute value of the Euclidean(or Hamming) distance between pairs of design points. In this paper we extend the gCD condition to asymmetric designs. In addition, a modified algorithm is applied for checking the equivalence of two designs.