• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.605-607
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• 2004

A class D digital audio amplifier with small size, low cost, and high quality is positively necessary in the multimedia era made of home theater system and the digital audio broadcasting (DAB). It is impossible to analyze the stability of the digital audio amplifier, which is based on the PWM signal processing. To solve this problem, the digital audio amplifier is analyzed using variable structure control theory which is one of nonlinear system theories. Moreover, the magnitude and the frequency of ripple signal, which generated by hysteresis in the comparator, is obtained using describing function which is useful to represent the input-output relation of nonlinear system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.357-365
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• 2003

The major problems with the conventional neural network, especially Back Propagation Neural Network, arise from the necessity of many training data for neural network learning and ambiguity in the relation of neural network structure to the convergence of solution. In this paper, the PNN is used as a pattern classifier to detect the damage of structure to avoid those drawbacks of the conventional neural network. In the PNN-based pattern classification problems, the probability density function for patterns is usually assumed by Gaussian distribution. But, in this paper, several probability density functions are investigated in order to select the most approriate one for structural damage assessment.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2299-2301
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• 1998

In this paper, a modified RBF (Radial Basis Function) neural network structure is suggested for the prediction of time series with non-linear, non-stationary characteristics. Conventional RBF neural network predicting time series by using past outputs is for sensing the trajectory of the time series and for reacting when there exists strong relation between input and hidden neuron's RBF center. But this response is highly sensitive to level and trend of time serieses. In order to overcome such dependencies, hidden neurons are modified to react to the increments of input variable and multiplied by increments(or decrements) of out puts for prediction. When the suggested structure is applied to prediction of Lorenz equation, and Rossler equation, improved performances are obtainable.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.212-212
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• 2015

So far, geomorphologic dispersion due to the heterogeneity characteristics of flow paths in a basin has been demonstrated as a major factor affecting to the hydrologic response function of a catchment. This effect has considered by many previous studies taking into account flow path length factors, especially in the application of width function. Based upon the analysis of topographic index, another important geomorphologic factor extracted from DEM data, this work presents a new factor named saturation to evaluate its effects to the formation of the well-known instantaneous unit hydrograph (IUH) in Nash model and drainage structure in a river basin. First, the geomorphologic parameters corresponding to different saturation conditions are computed from DEM data with the support of GIS software. Then, in the combination of hydrologic and geomorphologic data, effective rainfall in each saturation degree and the Nash parameters are calculated using excel. Finally, the verification process with direct runoff data is conducted using Fortran programming. This process is applied to five sub-watersheds in Bocheong catchment ($485.21km^2$) in Korea where the necessary data are available and believable. The results from this approach will improve researchers and students'understandings about the relationship between rainfall and runoff and its relation with drainage structure within a catchment.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.5-12
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• 2004

The data transformation between XML and Relation Database is made through the Principle of mapping bewtween them. There are two ways to access SQL Server, one is to assign SQL query to URL and the other is to use template file. MS-SQL server takes advantage of OpenXML function to transform the results of executing SQL query into XML documents. That is, OpenXML first makes node tree and then transforms row set data of XML documents into XML data of relation type. In order to insert XML data into database data. data is extracted from parsing XML documents using sp_xml_preparedocument procedure, and then the document structure is mapped into tree structure and stored in a table of database. Consequently, Data transformation between XML and Relation Database is made through mapping bewtween them. This article proposes the principle of mapping between XML and Relation Database and then shows the implementation of transformation between them so that it introduces the possibilty of bringing the extension and efficiency of data and various effects.

• The Journal of Industrial Distribution & Business
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• v.8 no.1
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• pp.5-13
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• 2017

Purpose - In this article, a dynamic model like a VAR is an appropriate choice for estimating the possible interrelationship between ownership structure and firm performance as a dynamic process. Research design, data, and methodology - Data of this work are collected from Chinese stock exchange including 350 Chinese-listed firms during the period of 1999-2012. We hypothesize that this interrelationship dynamically exists between ownership structure and firm performance. To examine the correlation, a panel Vector Auto-regression (PVAR) approach generated by GMM method is utilized to test the possible dynamic relation embedded in corporate governance. Another two dynamic analysis solutions such as orthogonalized impulse-response function and variance decomposition are also used simultaneously. Results - Findings of this study indicate the evidence that dynamically endogenous relationship exists between ownership structure and firm performance. Further, there is a dynamical correlation between investment and performance. Impulse response and variance decomposition illustrate that impact of a shock to variables themselves is the main source for their variability. Conclusions - The conclusion in this study is that there is a bidirectional and inter-temporal effect between proportion of ownership and corporate performance for a long run in accordance with impulse response function. Overall, our results suggest that corporate governance in China is more market oriented.

• Clinical and Experimental Reproductive Medicine
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• v.8 no.2
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• pp.29-33
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• 1981

Vesectomy has been increased as a popular method of birth control because it is simpler than other methods for men. But the vasectomy results in several problems such as relation to effect changes on the structure and function of the reproductive organ. The fate of non-ejaculated spermatozoa is postulated by some authors that those are disappeared by a progress of dissolution and reabsorption in the epididymis, and we have attempted to prove the true state of sperm-acrosome on the fine structure in vasectomized rats. The results were as follows: 1. Apical segments of the acrosome were swollen similar to the shape of club in many spermatozoa. 2. Discontinuities of the outer and inner acrosomal membranes were occasionally noted and there were complete losses of acrosomes in the certain place. 3. There was no evidence of significant changes in the nuclear structure, nor dilatation of the subacrosomal space. 4. Vasectomy might effect destructive changes in the acrosomes of the non-ejaculated spermatozoa in situ.

• Journal of Sasang Constitutional Medicine
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• v.12 no.2
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• pp.17-33
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• 2000

Purpose of this study is to investigate the correlation between Sung-Jung' concept of Sasang Constitutional Medicine and Brain. So, After studying the meaning of Sung-Jung' concept of Sasang Constitutional Medicine, I made a comparative study through the structure, function, development of Brain. The conclusions were as follows. 1. Human's brain acts a rational, control his actions. and It manage human body's physiology and pathology. and It perceive his surroundings, express his emotion through comprehension, synthesis, judgement about information from various fields. and It's abnormality bring about a spiritual, bodily injury. Therefore, human's brain have many correlation with Sung-Jung' concept of Sasang Constitutional Medicine. 2. Neocortex' function have many correlation with Sung' concept of Hearing-Sight-Smell-Taste (聽視嗅味=sensation=a highly mental capacity) through Ear-Eye-Nose-Mouse(耳目鼻?). 3. Limbic-system'function have many correlation with Jung' concept of Sorrow-Anger-Pleasure-Joy(哀怒喜榮=emotion) through Lung-Spleen-Liver-Kidney(肺脾肝腎) 4. Brain-stem' function have many correlation with vitalistic concept through Qui of Sorrow - Anger - Pleasure - Joy(哀怒喜樂之氣)' rise and fall. 5. Relation of emotions and diseases through Limbic system and Autonomic nervous system have many correlation with relation of Sung-Jung and diseases of Sasang Constitutional Medicine 6. Left-hemisphere' function that has superior power of verbal, analysis, logicality, consideration have many correlation with tendency of Soeumin and Taeumin. and Right-hemisphere' function that has superior power of emotion, non-verbal, imagination, spatial perception have many correlation with tendency of Soyangin and Taeyangin.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.183-188
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• 2005

Parallel processing in block cryptographic algorithm is difficult, because Feistel structure that is basis structure of block cryptographic algorithm is sequential processing structure. Therefore this paper changes these sequential processing structure and Feistel structure made parallel processing to be possible. This paper that apply this modified structure designed DES that have parallel Feistel structure. Proposed parallel Feistel structure could prove greatly block cryptographic algorithm's performance such as DES and so on that could not but have trade-off relation the data processing speed and data security interval because block cryptographic algorithm can not use pipeline method because of itself structural problem. Therefore, modified Feistel structure is going to display more superior security function and processing ability of high speed than now in case apply way that is proposed to SEED, AES's Rijndael, Twofish etc. that apply Feistel structure.

• International Journal of Automotive Technology
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• v.6 no.1
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• pp.45-52
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• 2005

Interrupted creep tests for investigating the structural degradation during creep were conducted for a Mod.9Cr-1Mo steel in the range of stress from 71 to 167 MPa and temperature from 873 to 923 K. The change of hardness and tempered martensitic lath width was measured in grip and gauge parts of interrupted creep specimens. The lath structure was thermally stable in static conditions. However, it was not stable during creep, and the structural change was enhanced by creep strain. The relation between the change in lath width and creep strain was described quantitatively. The change in Vickers hardness was expressed by a single valued function of creep LCR(life consumption ratio). Based on the empirical relation between strain and lath width, a model was proposed to describe the relation between change in hardness and creep LCR. The comparison of the model with the empirical relation suggests that about 65% of hardness loss is due to the decrease of dislocation density accompanied by the movement of lath boundaries. The role of precipitates on subboundaries was discussed in connection with the abnormal subgrain growth appearing in low stress regime.