• Journal of Integrative Natural Science
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• v.8 no.4
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• pp.258-266
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• 2015

Xanthine Oxidase is an enzyme, which oxidizes hypoxanthine to xanthine, and xanthine to uric acid. It is widely distributed throughout various organs including the liver, gut, lung, kidney, heart, brain and plasma. It is involved in gout pathogenesis. In this study, we have performed Comparative Molecular Field Analysis (CoMFA) on a series of 2-(indol-5-yl) thiazole derivatives as xanthine oxidase (XO) inhibitors to identify the structural variations with their inhibitory activities. Ligand based CoMFA models were generated based on atom-by-atom matching alignment. In atom-by-atom matching, the bioactive conformation of highly active molecule 11 was generated using systematic search. Compounds were aligned using the bioactive conformation and it is used for model generation. Different CoMFA models were generated using different alignments and the best model yielded a cross-validated $q^2$ of 0.698 with five components and non-cross-validated correlation coefficient ($r^2$) of 0.992 with Fisher value as 236.431, and an estimated standard error of 0.068. The predictive ability of the best CoMFA models was found to be $r^2_{pred}$0.653. The CoMFA study revealed that the $R_3$ position of the structure is important in influencing the biological activity of the inhibitors. Electro positive groups and bulkier substituents in this position enhance the biological activity.

• Korean Journal of Computational Design and Engineering
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• v.17 no.5
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• pp.364-374
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• 2012

In this paper, we proposed a data structure to represent structural components of solid rocket motors (SRM) in an automated design program. To propose the data structure, we searched the necessary functions for the automated design program should have. In order to design the structural components of solid rocket motors sufficiently with a design program, it should have the functions to represent the shapes of the components, the drawing and analysis models, the design variables, various product structures, interferences, characteristic properties, design equations, and tightening sets. By modifying the data structure of an element object that is a general purpose data structure to represent a general component of a product, a new data structure was proposed to satisfy all the necessary functions with optimum. Finally, a design program for the structural components of solid rocket motors was developed successfully with the proposed data structure.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.2
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• pp.8-14
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• 2008

Solid Rocket Motor(SRM) has advantages such as - high specific impulse, operational safety and simplicity in design and manufacturing process but thrust magnitude can't be controlled. For studying of pintle nozzle that can control the thrust magnitude of SRM, cold flow test and numerical analysis about needle type pintle shape were performed and results were presented in this paper. As the results of this study, pintle tip's shape and nozzle contour were important design parameters because thrust performance and variable thrust range of pintle nozzle depend on them. Especially, the thrust of needle typed pintle nozzle adopted in this test was predicted 13% higher than normal nozzle without pintle.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.16-19
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• 2002

This study was carried out to establish the standardized analysis method in order to decide accurate concentrations of hazardous metals in the air. Acid decomposition method used usually was compared to microwave digestion method. Comparing results of tested background concentration in blank filter, we found that the magnitude of element concentration was Na, Ca, K, Mg, Al and Ba by order. The element concentrations of Glass fiber filter were higher than those of Quartz fiber filter, and the number of undetected components in Glass fiber filter was lower than that in Quartz fiber filter. Thus it is supposed that the concentration of background elements in Glass fiber filter was higher than those in Quartz fiber filter The extraction rate of microwave digestion method was superior to those of acid decomposition method during the test of blank filter as well as SRM of NIST. In case of the SRM of NIST, the average extraction efficiency of acid decomposition Method and microwave pretreatment is 53.8∼82.7％, 81.3∼97.1％, respectively. This result might be caused by the closed system of Microwave, which make outflow and loss of components less. Also microwave digestion method has other merits such as the minimization of time, reagents, and contamination. Furthermore, if the extraction condition, extraction time and used acids are optimized, the better results will be represented.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.571-579
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• 2010

This paper reviews and analyzes converters for SRM(Switched Reluctance Motor) drive. Conventional classification focuses on the number of power switches and diodes. It is easy to find the number of semiconductors and the cost by counting the number of active components, but it does not show the important characteristics of a power converter. The voltage ratings for the power switches and diodes are also difficult to identify. This paper proposes a switched reluctance (SR) converter configuration that is classified based on the commutation type and magnetic energy path. The converter has three parts: utility interface, front-end circuit, and power converter. Based on the overview on the conventional SR drive, the most important characteristic of the converter is determined by the topology of front-end in conjunction with the power converter. An SR converter has two parts: front-end and power converter. Inasmuch as the capacitive front-end is widely used for voltage source converters, this paper focuses on topologies for the front-end.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.289-294
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• 2007

Solid Rocket Motor(SRM) has advantages such as - high specific impulse, operational safety and simplicity in design and manufacturing process, but thrust magnitude can't be controlled. For studying of pintle nozzle that can control the thrust magnitude of SRM, cold flow test and numerical analysis about needle type pintle shape were performed and results were presented in this paper. As the results of this study, pintle tip's shape and nozzle contour were important design parameters because thrust performance and variable thrust range of pintle nozzle depend on them. Especially, the thrust of needle typed pintle nozzle adopted in this test was predicted 13% higher than normal nozzle without pintle.

• ETRI Journal
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• v.27 no.6
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• pp.747-758
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• 2005

The problem of selection among competing models has been a fundamental issue in statistical data analysis. Good fits to data can be misleading since they can result from properties of the model that have nothing to do with it being a close approximation to the source distribution of interest (for example, overfitting). In this study we focus on the preference among models from a family of polynomial regressors. Three decades of research has spawned a number of plausible techniques for the selection of models, namely, Akaike's Finite Prediction Error (FPE) and Information Criterion (AIC), Schwartz's criterion (SCH), Generalized Cross Validation (GCV), Wallace's Minimum Message Length (MML), Minimum Description Length (MDL), and Vapnik's Structural Risk Minimization (SRM). The fundamental similarity between all these principles is their attempt to define an appropriate balance between the complexity of models and their ability to explain the data. This paper presents an empirical study of the above principles in the context of model selection, where the models under consideration are univariate polynomials. The paper includes a detailed empirical evaluation of the model selection methods on six target functions, with varying sample sizes and added Gaussian noise. The results from the study appear to provide strong evidence in support of the MML- and SRM- based methods over the other standard approaches (FPE, AIC, SCH and GCV).

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.1-9
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• 2016

In this study, two types of switched reluctance motors (SRMs) with segmental rotors are presented in detail. The first is a 6/5 segmental rotor type, whereas the second is a 12/8 segmental rotor type. Both motor types have the same stator, rotor, and winding configurations. The stator is constructed with special stator poles, namely, exclusively designed exciting and auxiliary poles. The rotor is constructed from a series of discrete segments, each of which is embedded into the nonmagnetic isolator. The windings are only wound on the exciting poles, and no winding is wound on the auxiliary poles. Given these configurations, short flux paths and high flux-linkage utilization rate are achieved in the proposed motors, which may reduce the magnetomotive force requirement and increase the electrical utilization of a machine. To verify the effectiveness of the proposed motors, their characteristics, such as magnetic flux distribution, flux-linkage, torque, radial force, and efficiency, are analyzed and compared with those of a conventional 12/8 SRM. Meanwhile, two prototypes, one for each proposed segmental rotor type, are also designed and manufactured. Finally, the validity of the proposed motors is further verified by test results.

• Journal of Power Electronics
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• v.11 no.6
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• pp.856-863
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• 2011

In this paper a novel method of the Ant Colony Optimization algorithm for rotor position estimation in Switched Reluctance Motors is presented. The data provided by the initial assumptions is one of the important aspects used to solve the problems relative to an Ant Colony algorithm. Considering the nature of a real ant colony, it was found that the ants have no primary data for deducing which is the shortest path in their initial iteration. They also do not have the ability to see the food sources at a distance. According to this point of view, a novel method is presented in which the rotor pole position relative to the corresponding stator pole in a switched reluctance motor is estimated with high accuracy using the active and inactive phase parameters. This new method gives acceptable results such as a desirable convergence together with an optimized and stable response. To the best knowledge of the authors, such an analysis has not been carried out previously.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.7
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• pp.2225-2238
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• 2022

For advanced healthcare services, a variety of agents should maintain reliable connections with the manager and communicate personal health and medical information. The ISO/IEEE 11073 standards provide convenient interoperability and the optimized exchange protocol (OEP) supports efficient communication for devices. However, the standard does not specify secure communication, and sensitive personal information is easily exposed through attacks. Malicious attacks may lead to the worst results owing to service errors, service suspension, and deliberate delays. All possible attacks on the communication are analyzed in detail, and the damage is specifically identified. In this study, novel secure communication schemes over the 20601 OEP are proposed by introducing an authentication process while maintaining compatibility with existing devices. The agent performs a secure association with the manager for mutual authentication. However, communication with mutual authentication is not completely free from attacks. Message encryption schemes are proposed for concrete security. The authentication process and secure communication schemes between the secure registered agent (SRA) and the secure registered manager (SRM) are implemented and verified. The experimental analysis shows that the complexities of the SRA and SRM are not significantly different from those of the existing agent and manager.