• Structural Engineering and Mechanics
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• v.12 no.6
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• pp.685-698
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• 2001

In this paper, a general method for the automatic search for Strut-and-Tie (S&T) models representative of possible resistant mechanisms in reinforced concrete elements is proposed. The representativeness criterion here adopted is inspired to the principle of minimum strain energy and requires the consistency of the model with a reference stress field. In particular, a highly indeterminate pin-jointed framework of a given layout is generated within the assigned geometry of the concrete element and an optimum truss is found by the minimisation of a suitable objective function. Such a function allows us to search the optimum truss according to a reference stress field deduced through a F.E.A. and assumed as representative of the given continuum. The theoretical principles and the mathematical formulation of the method are firstly explained; the search for a S&T model suitable for the design of a deep beam shows the method capability in handling the reference stress path. Finally, since the analysis may consider the structure as linear-elastic or cracked and non-linear in both the component materials, it is shown how the proposed procedure allows us to verify the possibilities of activation of the design model, oriented to the serviceability condition and deduced in the linear elastic field, by following the evolution of the resistant mechanisms in the cracked non-linear field up to the structural failure.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.632-638
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• 2002

In novelty detection, one attempts to discriminate abnormal patterns from normal ones. Novelty detection is quite difficult since, unlike usual two class classification problems, only normal patterns are available for training. Auto-Associative Multi-Layer Perceptron (AAMLP) has been shown to provide a good performance based upon the property that novel patterns usually have larger auto-associative errors. In this paper, we give a mathematical analysis of 2-layer AAMLP's output characteristics and empirical results of 2-layer and 4-layer AAMLPs. Various activation functions such as linear, saturated linear and sigmoid are compared. The 2-layer AAMLPs cannot identify non-linear boundaries while the 4-layer ones can. When the data distribution is multi-modal, then an ensemble of AAMLPs, each of which is trained with pre-clustered data is required. This paper contributes to understanding of AAMLP networks and leads to practical recommendations regarding its use.

• Journal of Multimedia Information System
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• v.3 no.3
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• pp.91-96
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• 2016

Network security is an interesting area in Information Technology. It has an important role for the manager monitor and control operating of the network. There are many techniques to help us prevent anomaly or malicious activities such as firewall configuration etc. Intrusion Detection System (IDS) is one of effective method help us reduce the cost to build. The more attacks occur, the more necessary intrusion detection needs. IDS is a software or hardware systems, even though is a combination of them. Its major role is detecting malicious activity. In recently, there are many researchers proposed techniques or algorithms to build a tool in this field. In this paper, we improve the performance of IDS. We explore and analyze the impact of activation functions applying to recurrent neural network model. We use to KDD cup dataset for our experiment. By our experimental results, we verify that our new tool of IDS is really significant in this field.

• Journal of the Korean institute of surface engineering
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• v.47 no.1
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• pp.48-52
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• 2014

Electric conductivities of $LaCl_3$-KCl binary melts have been measured by the Kohlausch bridge method over the range from their liquidus temperatures to about 1280 K. The electric conductivity increased with the content of KCl for all over the composition range of binary melts. The composition dependence of the electric conductivity and molar conductivity for the binary melt showed a non-linear relation from the additivity line, and the deviation showed a maximum value at about 60 mol.% KCl. The deviation implies the existence of complex ion of $LaCl^{4-}$ in the melt. Activation energy for electric conductivity of the binary melts decreased monotonously with increasing content of KCl.

• Journal of the Korean institute of surface engineering
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• v.39 no.6
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• pp.282-287
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• 2006

Viscosities of $LaCl_3-NaCl$ binary melts were measured by the capillary method over the range of their liquidus temperatures to about 1200K. The cell constant were determined by using pure water. The results obtained are summerized as follows: Viscosities were decreased with the content of NaCl for all over the composition range of binary melts. Composition - viscosity relation for the binary melts show a non-linear from the additivity line and the deviations shows a maximum at about 60 mol% NaCl. This suggests the existence of the complex ion of $LaCl_4^-$ in the melt. Activation energy for viscous flow of the binary melts decrease monotonously with the increasing content of NaCl.

• Bulletin of the Korean Chemical Society
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• v.21 no.5
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• pp.477-482
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• 2000

Phenyl group migration within protonated 1,2-diphenyl hydrazines has been studied theoretically using the semi-empirical AM1 method. This reaction proceeds through a 3-membered cyclic transition state and requires high activation energy. In the reactant, there was no resonance stabilization for the moving Z-ring, however, hammett $p_Z^+$ values are large due to the direct involvement of the Z-ring inthe reaction, and the development of a negative charge on the reaction center gives them a posifive value. In the case of the non-moving ring, $p_Y^+$ values are small and negative owing to the smaller positive charge increase in the reaction center. The cross-interaction constant, $p_YZ^+$, was obtained from the activation enthalpies, using the multipe linear regression methdo, and the interaction between two substituents, Y and Z, is examined.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.13-18
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• 2024

To develop flexible electrode materials for wearable devices, we investigated the electrochemical characteristics of carbon fibers tow according to pretreatment. And an electrochemical non-enzymatic sensor was fabricated using glucose as a target. The carbon fibers tow was pretreated through desizing and activation processes, and activation was performed in two ways: chemical oxidation and electrochemical oxidation. Surface morphology of carbon fibers tow samples was observed by SEM and their electrochemical characteristics and sensing performance were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Carbon fibers tow samples showed improved electrochemical properties such as reduced R_et, ΔE_p, and increased I_p through pretreatment. And similar electrochemical properties were obtained with both activation methods. We selected electrochemically activated carbon fibers tow as the final electrode material for application of electrochemical sensor. The non-enzymatic glucose sensor based on this electrode has an enhanced sensitivity of 0.744 A/mM (in a linear range of 0.09899~3.75423 mM) and 0.330 mA/mM (3.75423~50 mM), respectively. Through this study, the possibility of using carbon fibers tow was confirmed as an electrode material. It is expected to be used as basic research for development of high-performance flexible electrode materials.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.368-371
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• 1999

In this paper, we propose a neural network processor architecture with on-chip learning and with reconfigurability according to the data dependencies of the algorithm applied. For the neural network model applied, the proposed architecture can be configured into either SIMD or SRA(Systolic Ring Array) without my changing of on-chip configuration so as to obtain a high throughput. However, changing of system configuration can be controlled by user program. To process activation function, which needs amount of cycles to get its value, we design it by using PWL(Piece-Wise Linear) function approximation method. This unit has only single latency and the processing ability of non-linear function such as sigmoid gaussian function etc. And we verified the processing mechanism with EBP(Error Back-Propagation) model.

• Journal of the Korean institute of surface engineering
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• v.50 no.4
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• pp.237-243
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• 2017

We demonstrated the thin film deposition of sodium phosphorous oxynitride (NaPON) via RF magnetron sputtering of $Na_3PO_4$, as a solid-state Na-ion conductor similar to lithium phosphorous oxynitride (LiPON), which is a commonly used solid electrolyte. The deposited NaPON thin film was characterized by scanning electron microscopy, X-ray diffractometry, and electrochemical impedance spectroscopy, to investigate the feasibility of the solid-state electrolyte in several different cell configurations. The key properties of a solidstate electrolyte, i.e., ionic conductivity and activation energy, were estimated from the complex non-linear least square fitting of the measured impedance spectra at various temperatures in the range of $27-90^{\circ}C$. The ionic conductivity of the NaPON film was measured to be $8.73{\times}10^{-6}S\;cm^{-1}$ at $27^{\circ}C$, which was comparable to that of the LiPON film. The activation energy was estimated to be 0.164 eV, which was lower than that of the LiPON film (0.672 eV). The obtained values encourage the use of a NaPON thin film in the future as a reasonable solid-state electrolyte.

• Journal of the Korean Chemical Society
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• v.36 no.1
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• pp.113-124
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• 1992

The pattern recognition methods of chemometrics have been applied to multivariate data, for which ninety four Korean ancient glass pieces have been determined for 12 elements by neutron activation analysis. For the purpose, principal component analysis and non-linear mapping have been used as the unsupervised learning methods. As the result, the glass samples have been classified into 6 classes. The SIMCA (statistical isolinear multiple component analysis), adopted as a supervised learning method, has been applied to the 6 training set and the test set. The results of the 6 training set were in accord with the results by principal component analysis and non-linear mapping. For test set, 17 of 33 samples were each allocated to one of the 6 training set.