• Journal of the Korean Chemical Society
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• v.14 no.1
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• pp.119-122
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• 1970

In those six kinds of diamine salt crystal of which their structures had already been determined up to date, commonly one molecule of diamine and two molecules of acid were combined; although the crystal of benzidine perchlorate, only one molecule each of benzidine and perchloric acid were combined. At the case of benzidine perchlorate, one molecule acts as the role of two molecules by coincidence of the center of symmetry point of both the lattice and molecule, and perchlorate ion is locating symmetrically between two -$NH_2$ groups of different benzidine molecule, therefore benzidine and acid could be combined together with 1:1 by mole ratio. When forming the salt with diamine and acid, the combining mole ratio would be determined in accordance with the relationship between the symmetry element that presented by the space group and the symmetry element of diamine salt melecule.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.265-270
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• 2005

This paper presents a new attitude stabilization and control of an unmanned helicopter based on neural network compensation. A systematic derivation on the dynamics of an unmanned small-scale helicopter is performed. Combined rotor-fuselage-tail dynamics is derived in body-fixed reference frame with its origin at the C.G. of the helicopter. And the resulting nonlinear equation of motion consists of 6-DOF air vehicle dynamics as well as the rotor flapping and engine torque equations. A simulation model was modified using the existing simulator for an unmanned helicopter dynamic model, which reflects the unmanned test helicopter(CNUHELI). The dynamic response of the refined model was compared with the flight test data. It can be shown that a good coincidence was accomplished between the real unmanned helicopter system and the mathematical model. This dynamic model was linearized for classical controller design using small perturbation method. A Neuro-PD control system was designed for both longitudinal and lateral flight modes, and the results were compared with the PD-only control response. Simulation results show that the proposed Neuro-PD control system demonstrates better performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.9
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• pp.1555-1561
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• 2003

Finite element analysis using modern constitutive equation is one of the most general tools to simulate the deformation behavior and to predict the life of the structure. Constitutive equation becomes complicated so as to predict the material behavior more accurately than the classical models. Because of the complexity of constitutive model, numerical treatment becomes so difficult that the calculation should be verified carefully. One-element tests, simple tension or simple shear, are usually used to verify the accuracy of finite element analysis using complicated constitutive model. Since this test is mainly focused on the time integration scheme, it is also necessary to verify the equilibrium iteration using material stiffness matrix and to compare FE results with solution of structures. In this investigation, viscoplastic solution of thick walled cylinder was derived considering axial constraints and was compared with the finite element analysis. All the numerical solutions showed a good coincidence with FE results. This numerical solution can be used as a verification tool for newly developed FE code with complicated constitutive model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.501-505
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• 2013

It is well known that monolithic glass has specific coincidence dip allowing transmittance of noise around the critical frequency. Laminated glass, made of a polyvinyle butyral(PVB) interlayer sandwiched by two panes of glass sheet, has long served for the advantage in noise attenuation properties as well as the safety purpose. More research on the improvement of sound insulation performance is needed, considering much of the noise is still transmitted through the glass. As a preliminary study, authors have made several test specimens, varied combinations of glass and interlayer film, to optimize the acoustic performance. Experimental investigation was carried out to study the sound transmission loss of test specimens in the reverberation chamber by using sound intensity method. Several new applications, instead of the existing PVB laminated glass, show better results in sound transmission loss and low temperature have a bad influence on the acoustic performance.

• Environmental Engineering Research
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• v.14 no.2
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• pp.111-119
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• 2009

A prototype GIS-based decision support system (DSS) was developed by using a database management system (DBMS), a model management system (MMS), a knowledge-based system (KBS), a graphical user interface (GUI), and a geographical information system (GIS). The method of selecting a dispersion model or a modeling scheme, originally devised by Park and Seok, was developed using our GIS-based DSS. The performances of candidate models or modeling schemes were evaluated by using a single index(statistical score) derived by applying fuzzy inference to statistical measures between the measured and predicted concentrations. The fumigation dispersion model performed better than the models such as industrial source complex short term model(ISCST) and atmospheric dispersion model system(ADMS) for the prediction of the ground level $SO_2$ (1 hr) concentration in a coastal area. However, its coincidence level between actual and calculated values was poor. The neural network models were found to improve the accuracy of predicted ground level $SO_2$ concentration significantly, compared to the fumigation models. The GIS-based DSS may serve as a useful tool for selecting the best prediction model, even for complex terrains.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.34.2-34.2
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• 2016

X-ray cavities are typically detected as surface brightness depression in X-ray diffuse emission from hot gas in high resolution X-ray images (i.e., Chandra and XMM-Newton). Showing the coincidence of location with radio jets, X-ray cavities imply that the radio jets interact with interstellar/intergalactic medium. It is important to understand them since they can be a clue of understanding AGN feedback to their host galaxies. To understand the physics of the AGN feedback, X-ray cavity has been actively studied while there are only a few statistical studies on X-ray cavity based on small or incomplete samples. Hence, a systematic study with a large sample is needed. With the condition of sufficient X-ray photons to detect surface brightness depression, we constructed a large sample of 133 galaxy clusters, galaxy groups, and individual galaxies to investigate X-ray cavities. We detected 201 cavities from 94 objects using two detection methods (i.e., beta-modeling and unsharp masking method), and confirmed the cavity size-distance relation over a large dynamical range. The size-distance relation does not vary for different environments (i.e., galaxy cluster, groups, and individual galaxies), suggesting that there is little environmental effect on the formation of X-ray cavity.

• Journal of the Korean Magnetics Society
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• v.18 no.2
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• pp.63-66
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• 2008

In order to the magnetization and magnetic entropy change for superparamagnetic ferrite nanoparticles, ultrafine cobalt ferrite particles were synthesized using a mircoemulsion method. The peak of X-ray diffraction pattern corresponds to a cubic spinel structure with the lattice constant 8.40 $\AA$. The average particle size, determined from X-ray diffraction line-broadening using Scherrer's, is 7.9 nm. The maximal magnetizations measured at 5 and 300 K are 24.3 emu/g and 17.2 emu/g, respectively. Superparamagnetic behavior of the sample is confirmed by the coincidence of the M vs. H/T plots at various temperatures. According to the thermodynamic theory, magnetic entropy change decreases with increasing temperature.

• The Korean Journal of Rehabilitation Nursing
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• v.6 no.1
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• pp.14-25
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• 2003

Purpose: To investigate nutritional status of inpatients by using subjective, and objective evaluation methods and to find the relationship between them. Method: The subjects were 101 inpatients with medical health problems at a university hospital. Nutritional status was evaluated by the Subjective Global Assessment(SGA) and physical assessment including percentage of weight loss, serum albumin, hemogloin, and hematocrit. Data were analyzed using frequency, percentage, mean, Kendall's tau. Results: Grouping by the SGA, 61.4% were classified as severe malnutrition group. When applying the objective methods(physical assessment), 1.9~42.6% were diagnosed as malnutrition each item. The percentage of weight loss during previous 1~6month(${\tau}=.43{\sim}.54$, P=.0001), serum albumin(${\tau}=-.26$, P=.0003), hemoglobin of male(${\tau}=-.38$, P=.0001), and hematocrit of male(${\tau}=-.34$, P=.0001) were significantly correlated with SGA score. The coincidence rate of nutrition evaluation between the objective methods and SGA were 27.7~35.6%, 20.8%, 47.5%, 58.4% in percentage of weight loss, albumin, hemoglobin, and hematocrit. Conclusion: These findings showed a majority of inpatients were exposed to the risk of malnutrition. We recommend to evaluate inpatients' nutritional status periodically and to develop nursing intervention to solve their nutritional problems.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.82-87
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• 2001

In this paper we described the generation method of interface logic which can be replace between IP and IP handshaking signal with asynchronous logic circuit. Especially, we suggest the new \"Waveform Conversion Algorithm : Wave2VHDL\", if only mixed asynchronous timing waveform suggested which level type input and pulse type input for handshaking, we can convert waveform to flowchart and then replaced with VHDL code according to converted flowchart. Also, we assure that asynchronous electronic circuits for IP interface are generated by applying extracted VHDL source code from suggested algorithm to conventional domestic/abroad CAD Tool, and then we proved that coincidence simulation result and suggested timing diagram.g diagram.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.705-706
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• 2006

Generally Short Circuit Test of transformers are tested according to IEEE std C57.12.00-2000, IEC 60076-5(2000-07), ES148(1998.6.26) or KS C4309(2003). But ES148(1998.6.26) is same as IEEE std C57. 12.00-2000 and KS C4309(2003) is revising coincidence with IEC 60076-5(2000-07). On this study condition of the transformers before short circuit test, calculation method for test current peak value, tolerance on the asymmetrical peak and r.m.s value, short circuit testing procedure, number of short circuit test, duration short circuit test, and detection of faults and evaluation of short circuit test result will be compared with ANSI and IEC.