• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.191-196
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• 2011

In this study simple and sensitive high performance liquid chromatographic method using a commercially available column, was developed and validated for the determination of zolpidem tartrate in human plasma. The developed method with suitable validation was applied to a bioequivalence study of two different kinds of zolpidem tartrate. Two different formulations containing 10 mg of zolpidem tartate (CAS : 99294-93-6) were compared in 24 healthy male volunteers in order to compare the bioavailability and prove the bioequivalence. The study was performed in an open, single dose randomized, 2-sequence, cross-over design in 24 healthy male volunteers with a one-week washout period. Blood samples for pharmacokinetic profiling were drawn at selected times during 12 h. The mean $AUC_{0-12h}$, $C_{max}$, $T_{max}$ and $T_{1/2}$ were $676.6{\pm}223.4$ $ng{\cdot}h{\cdot}mL^{-1}$, $177.4{\pm}34.2$ $ng{\cdot}mL^{-1}$, and $0.8{\pm}0.4$ and $3.5{\pm}2.1$, respectively, for the test formulations, and $640.7{\pm}186.6$ $ng{\cdot}h{\cdot}mL^{-1}$, $193.0{\pm}64.5$ $ng{\cdot}mL^{-1}$, and $0.9{\pm}0.4$ and $2.7{\pm}0.9$, respectively, for the reference formulation. Both primary target parameters $AUC_{0-12h}$ and $C_{max}$ were log-transformed and tested parametrically by analysis of variance (ANOVA). 90% confidence intervals of $AUC_{0-12h}$ and $C_{max}$ were in the range of acceptable limits of bioequivalence (80-125%). Based on these results, the two formulations of zolpidem tartate are considered to be bioequivalent.

• Journal of the Korean association of regional geographers
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• v.22 no.1
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• pp.251-266
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• 2016

Intelligent interpolation methods such as dasymetric mapping are considered to be the best way to disaggregate zone-based population data by observing and utilizing the internal variation within each source zone. This research reviews the advantages and problems of the dasymetric mapping method, and presents a geographically weighted regression (GWR) based method to take into consideration the spatial heterogeneity of population density - land cover relationship. The locally adaptive intelligent interpolation method is able to make use of readily available ancillary information in the public domain without the need for additional data processing. In the case study, we use the preclassified National Land Cover Dataset 2011 to test the performance of the proposed method (i.e. the GWR-based multi-class dasymetric method) compared to four other popular population estimation methods (i.e. areal weighting interpolation, pycnophylactic interpolation, binary dasymetric method, and globally fitted ordinary least squares (OLS) based multi-class dasymetric method). The GWR-based multi-class dasymetric method outperforms all other methods. It is attributed to the fact that spatial heterogeneity is accounted for in the process of determining density parameters for land cover classes.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.218-224
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• 2012

Recently, as the needs of developing the micro autonomous underwater vehicle (AUV) are increasing, the acquisition of the elementary technology is urgent. While they mostly utilizes information of the forward looking sonar (FLS) in conventional studies of the local path control as an elementary technology, it is desirable to use the obstacle avoidance sonar (OAS) because the size of the FLS is not suitable for the micro AUV. In brief, the local path control system based on the OAS for the micro AUV operates with the following problems: the OAS offers low bearing resolution and local range information, it requires the system that has reduced power consumption to extend the mission execution time, and it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent local path control algorithm based on the beam modeling of OAS with the evolution strategy (ES) and the fuzzy logic controller (FLC), is proposed. To verify the performance and analyze the characteristic of the proposed algorithm, the course control of the underwater flight vehicle (UFV) is performed in the horizontal plane. Simulation results show that the feasibility of real application and the necessity of additional work in the proposed algorithm.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.1
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• pp.1-6
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• 2014

In this study, we propose optimized RBFNNs based on night vision face recognition simulator with the aid of $(2D)^2$ PCA algorithm. It is difficult to obtain the night image for performing face recognition due to low brightness in case of image acquired through CCD camera at night. For this reason, a night vision camera is used to get images at night. Ada-Boost algorithm is also used for the detection of face images on both face and non-face image area. And the minimization of distortion phenomenon of the images is carried out by using the histogram equalization. These high-dimensional images are reduced to low-dimensional images by using $(2D)^2$ PCA algorithm. Face recognition is performed through polynomial-based RBFNNs classifier, and the essential design parameters of the classifiers are optimized by means of Differential Evolution(DE). The performance evaluation of the optimized RBFNNs based on $(2D)^2$ PCA is carried out with the aid of night vision face recognition system and IC&CI Lab data.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.7
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• pp.970-976
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• 2007

In this study, Polynomial Network Pattern Classifier(PNC) based on Fuzzy Inference Mechanism is designed and its parameters such as learning rate, momentum coefficient and fuzzification coefficient are optimized by means of Particle Swarm Optimization. The proposed PNC employes a partition function created by Fuzzy C-means(FCM) clustering as an activation function in hidden layer and polynomials weights between hidden layer and output layer. Using polynomials weights can help to improve the characteristic of the linear classification of basic neural networks classifier. In the viewpoint of linguistic analysis, the proposed classifier is expressed as a collection of "If-then" fuzzy rules. Namely, architecture of networks is constructed by three functional modules that are condition part, conclusion part and inference part. The condition part relates to the partition function of input space using FCM clustering. In the conclusion part, a polynomial function caries out the presentation of a partitioned local space. Lastly, the output of networks is gotten by fuzzy inference in the inference part. The proposed PNC generates a nonlinear discernment function in the output space and has the better performance of pattern classification as a classifier, because of the characteristic of polynomial based fuzzy inference of PNC.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.163-168
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• 2015

In this paper, 433/865MHz dual band antenna is proposed by using IFA structure of a PCB antenna, the performance was improved by changing of the space between the feed point and short strip, varying the gap between the radiator and the ground plane and adding the branch line in the proposed antenna. To confirm the characteristics of the antenna parameters, HFSS from ANSYS Inc. was used for the analysis. RFID frequency band of ISO-18000-7 is 433MHz and EU-RFID frequency band of ISO-18000-6 is from 865.5 to 867.5MHz. Each of the 433/865MHz bandwidth of the proposed antenna is 5.2MHz and 18.2MHz. The maximum 433MHz antenna gain is -5.74dBi, the maximum 865MHz antenna gain is -3.36dBi. The Jig size of the proposed antenna is $60{\times}44{\times}1mm$ and the size of the antenna area $44{\times}21mm$. The results proved the possibility of the practical use on 433/865MHz by using the IFA structure that came from comparing and analyzing the measured and simulated data of the antenna.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.60-69
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• 2000

This paper describes a single-chip full-custom implementation of pipelined adaptive decision-feedback equalizer(PADFE) using a 0.25-${\mu}m$ CMOS technology for wide-band wireless digital communication systems. To enhance the throughput rate of ADFE, two pipeline stages are inserted into the critical path of the ADFE by using delayed least-mean-square(DLMS) algorithm. Redundant binary (RB) arithmetic is applied to all the data processing of the PADFE including filter taps and coefficient update blocks. When compared with conventional methods based on two's complement arithmetic, the proposed approach reduces arithmetic complexity, as well as results in a very simple complex-valued filter structure, thus suitable for VLSI implementation. The design parameters including pipeline stage, filter tap, coefficient and internal bit-width, and equalization performance such as bit error rate (BER) and convergence speed are analyzed by algorithm-level simulation using COSSAP. The single-chip PADFE contains about 205,000 transistors on an area of about $1.96\times1.35-mm^2$. Simulation results show that it can safely operate with 200-MHz clock frequency at 2.5-V supply, and its estimated power dissipation is about 890-mW. Test results show that the fabricated chip works functionally well.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.196-208
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• 2007

An analytical model is proposed for an optically controlled Metal Semiconductor Field Effect Transistor (MESFET), known as Optical Field Effect Transistor (OPFET) considering the diffusion fabrication process. The electrical parameters such as threshold voltage, drain-source current, gate capacitances and switching response have been determined for the dark and various illuminated conditions. The Photovoltaic effect due to photogenerated carriers under illumination is shown to modulate the channel cross-section, which in turn significantly changes the threshold voltage, drainsource current, the gate capacitances and the device switching speed. The threshold voltage $V_T$ is reduced under optical illumination condition, which leads the device to change the device property from enhancement mode to depletion mode depending on photon impurity flux density. The resulting I-V characteristics show that the drain-source current IDS for different gate-source voltage $V_{gs}$ is significantly increased with optical illumination for photon flux densities of ${\Phi}=10^{15}\;and\;10^{17}/cm^2s$ compared to the dark condition. Further more, the drain-source current as a function of drain-source voltage $V_{DS}$ is evaluated to find the I-V characteristics for various pinch-off voltages $V_P$ for optimization of impurity flux density $Q_{Diff}$ by diffusion process. The resulting I-V characteristics also show that the diffusion process introduces less process-induced damage compared to ion implantation, which suffers from current reduction due to a large number of defects introduced by the ion implantation process. Further the results show significant increase in gate-source capacitance $C_{gs}$ and gate-drain capacitance $C_{gd}$ for optical illuminations, where the photo-induced voltage has a significant role on gate capacitances. The switching time ${\tau}$ of the OPFET device is computed for dark and illumination conditions. The switching time ${\tau}$ is greatly reduced by optical illumination and is also a function of device active layer thickness and corresponding impurity flux density $Q_{Diff}$. Thus it is shown that the diffusion process shows great potential for improvement of optoelectronic devices in quantum efficiency and other performance areas.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.19-27
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• 2010

Aging and severe environments are major causes of damage in reinforced concrete (RC) structures such as buildings and bridges. Deterioration such as concrete cracks, corrosion of steel, and deformation of structural members can significantly degrade the structural performance and safety. Therefore, effective and easy-to-use methods are desired for repairing and strengthening such concrete structures. Various methods for strengthening and rehabilitation of RC structures have been developed in the past several decades. Recently, FRP composite materials have emerged as a cost-effective alternative to the conventional materials for repairing, strengthening, and retrofitting deteriorating/deficient concrete structures, by externally bonding FRP laminates to concrete structural members. The main purpose of this study is to investigate the effectiveness of adaptive neuro-fuzzy inference system (ANFIS) in predicting behavior of circular type concrete column retrofitted with FRP. To construct training and testing dataset, experiment results for the specimens which have different retrofit profile are used. Retrofit ratio, strength of existing concrete, thickness, number of layer, stiffness, ultimate strength of fiber and size of specimens are selected as input parameters to predict strength, strain, and stiffness of post-yielding modulus. These proposed ANFIS models show reliable increased accuracy in predicting constitutive properties of concrete retrofitted by FRP, compared to the constitutive models suggested by other researchers.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.503-511
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• 2008

This paper presents the results of an analytical and experimental study on the performance of reinforced concrete beams subjected to pure torsion. The main parameters of the experimental tests were amount of torsional reinforcement and the ratio of the transverse torsional reinforcement to the longitudinal torsional reinforcement. The test results indicated that the maximum amount of torsional reinforcement required in ACI 318-05 code underestimated almost twice as much as the observed maximum amount of torsional reinforcement. Comparisons between the tested and calculated torsional behaviors of the 102 beams showed that the torsional failure modes of ACI 318-05 code disagreed with the observed failure modes. In addition, the torsion provisions in ACI 318-05 code overestimate the torsional strength of the RC beams in which relatively large amount of torsional reinforcement were reinforced, while underestimate for the beams with small amount of torsional reinforcement. This discrepancy between the theoretical ultimate torsional strength as given by the ACI 318-05 code and the experimental one can be due to neglecting the tension stiffening effect and the contribution of the torsional strength by concrete.