• Advances in environmental research
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• v.4 no.2
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• pp.83-104
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• 2015

Air Quality Index (AQI) is a pointer to broadcast short term air quality. This paper presents one day ahead AQI forecasting on seasonal basis for three major cities in Maharashtra State, India by using Artificial Neural Networks (ANN) and Genetic Programming (GP). The meteorological observations & previous AQI from 2005-2008 are used to predict next day's AQI. It was observed that GP captures the phenomenon better than ANN and could also follow the peak values better than ANN. The overall performance of GP seems better as compared to ANN. Stochastic nature of the input parameters and the possibility of auto-correlation might have introduced time lag and subsequent errors in predictions. Spectral Analysis (SA) was used for characterization of the error introduced. Correlational dependency (serial dependency) was calculated for all 24 models prepared on seasonal basis. Particular lags (k) in all the models were removed by differencing the series, that is converting each i'th element of the series into its difference from the (i-k)"th element. New time series is generated for all seasonal models in synchronization with the original time line & evaluated using ANN and GP. The statistical analysis and comparison of GP and ANN models has been done. We have proposed a promising approach of use of GP coupled with SA for real time prediction of seasonal multicity AQI.

• Journal of the Korean Data and Information Science Society
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• v.24 no.2
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• pp.289-301
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• 2013

We analyze respondents' reaction to Obama's advertisement, titled 'Fix the Economy'. These respondents are divided into three groups of democratic party, republican party and independent group. By manipulating the skin complexion of the Obama photo, participants were either exposed to the dark or light version of the Obama photograph. In order to obtain decorrelated stationary data, we have applied the discrete Fourier transform to each curve and then we have applied Fan (1998)'s adaptive Neyman test to the discrete Fourier transformed data. As a result, a significant difference is found out only in the independent group.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1356-1363
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• 1999

In this paper, a new method for controlling the pointing device using EOG(electrooculogram) signal generated from eye movement was suggested. The basic idea of the method is to control the direction of pointer, as using the results of measuring each component of the horizontal EOG and the vertical EOG by angle of eye-gaze. As a practical example, pointing device controlling the personal computer's pointer is manufactured. The designed pointing device consists of pre-amplifier, A/D converter, serial transmission device and PC program. That is, first, the EOG is amplified by pre-amplifier. Secondly, the amplified EOG is digitized and transmitted to personal computer by PIC16C74A. Finally, the software for controlling the pointer on personal computer is programed. As the result, the measured horizontal EOG and vertical EOG by eye-gaze angle had high linearity; the correlation coefficients of the regression line were 0.998 and 0.996 respectively. And the developed pointing device is able to control the personal computer's pointer, and the average of the errors between the objective value and the observed value had 3.77% for horizontal axis and 5.85% for vertical axis. The pointing device developed in this study is able to control personal computer's pointer by subject's eye movement, that is, the user's intention. Furthermore, the algorithm of this study is applicable for many field, such as a new method remote control, a new wheelchair control and so forth.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.4
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• pp.64-69
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• 2009

This paper addresses the simulation methodology of signal integrity and power integrity for mobile display modules. The proposed technique can be applied to analyse a circuit module which consist of connector, FPCB and driver ICs. The recent demand of serial interconnection technology in the mobile display industry needs delicate impedance control of signal and power traces to prohibit system malfunctioning and to reduce electromagnetic field radiation. Based on the S-parameter and Z-parameter analysis, we analyse the correlation between frequency-domain and time-domain measurements. With multi-port macros, signal integrity can be included in power integrity analysis in time domain.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.293-296
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• 2007

In this paper, we propose the systolic array architecture for the vector median filter. In the color image processing, the vector signal (i.e. the color) consists of three elements, red, green and blue. The vector median filter is very effective to utilize the correlation among red, green and blue elements. The computational complexity of the proposed architecture for computing the vector median of N vector signals is (N+2) clock periods compared to the (3N+1) clock periods in the previous method. In addition to, the input vector signals can be loaded in serial in the proposed architecture. In the previous method, N input vector signals should be loaded to the vector median filter in parallel at the first clock. The proposed architecture is implemented with FPGA.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.441-448
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• 2012

This paper proposes a multiband Multi-Input Multi-output(MIMO) antenna for universal serial bus(USB) dongle application. The proposed MIMO antenna consists of a modified meander strip line and inverted L stub. The two radiating elements of the MIMO antenna are symmetrically placed with respect to the center of the ground plane. The fabricated antenna satisfied a VSWR below 3 and an efficiency over 35 % in the LTE band 13, 17(704 MHz-787 MHz), DCS/PCS/WCDMA band(1.71 GHz-2.17 GHz), and LTE band 7(2.5 GHz-2.7 GHz). The envelope correlation coefficient(ECC) has below 0.45 in the LTE band 13, 17 and 0.1 in the DCS/PCS/WCDMA band and LTE band 7, respectively.

• Journal of the Korean housing association
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• v.4 no.2
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• pp.1-9
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• 1993

This study is a basic research to analyze and estimate the light environment of the classroom by serial correlation of time. Its purpose lies in the comparison by time period in order In select floor for laboratory and to calculate the uniformity factor. The proving ground is T building in W university, Which is five floor of central hall type. The subject of investigating is eight classrooms, four rooms in South and North, from the second floor that is net influenced by the shelter. The results that compared and estimated them in the illumination of daylight, Uniformity factor, Daylight factor, are as follows1. The illumination of classroom in South and North is over 10001x, but the classroom in North is good and the classroom in South excellent.2. The uniformity factor of classroom in South is good and that of classroom in North is normal.3. The daylight factor of each classroom is over 5% but the classroom in South is above that in North. The classroom in South surpasses the classroom in North in the general light environment and the classroom in third and fourth floor is so better than that in second and fifth floor in the condition of laboratory In the uniformity factor, the classroom in fourth can be better than any classroom.

• Journal of Korean Foot and Ankle Society
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• v.17 no.4
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• pp.264-271
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• 2013

Purpose: We aimed to analyze the effect of fixation tightness of the syndesmotic screw and its indwelling period on the recurrence of the syndesmosis widening after screw removal and the clinical outcomes. Materials and Methods: Forty consecutive patients with acute syndesmotic injury were retrospectively reviewed. The tibiofibular clear space is measured by digitalized measurement tool on serial radiographs. We analyzed the effect of time from trauma to fixation, syndesmotic screw indwelling duration, and fixation methods. Residual symptoms at the last follow up were evaluated. The student t-test, correlation test, and chi-square test were used for statistical analysis. Results: Eighteen ankles (45%) had recurrent syndesmosis widening (greater than 5% compared to the contralateral side). Seven patients had pain and five had limitation of motion in the ankle joint. Fixation tightness had significant effect on reducing the recurrence while the severity of the initial widening, time to fixation, and duration of fixation did not affect the outcome. Conclusion: Tight fixation of syndesmotic screw is essential for achieving final syndesmotic stability and reducing recurrence.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.103-117
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• 2017

In longitudinal data analysis, the serial correlation of repeated outcomes must be taken into account using covariance matrix. Modeling of the covariance matrix is important to estimate the effect of covariates properly. However, It is challenging because there are many parameters in the matrix and the estimated covariance matrix should be positive definite. To overcome the restrictions, several Cholesky decomposition approaches for the covariance matrix were proposed: modified autoregressive (AR), moving average (MA), ARMA Cholesky decompositions. In this paper we review them and compare the performance of the approaches using simulation studies.

• Journal of Distribution Research
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• v.1 no.1
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• pp.83-107
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• 1996

The concern of external environment is growing up in the field of channel distribution. In the former channel distribution, the channel distribution environment is little bit unmoveable owing to a powerful manufacture control against poor distributor. Therefore intra-efficiency is channel member's core interest. The structure of channel governance, however, come to be changable because of the mature distributor power against manufacturer such as a Price Break, JIT of channel governance, and a serial of change. Accordingly, it is acceptable that the interest of external-environment of channel members' is more and more enlarged, and external-environment change in the channel distribution make the serious problems in intraorganizational system. Thus, it is meaningful that this study try to discover the consumer power as external environment factor and to find the best strategy to overcome this consumer power. Resource dependence theory, Transaction cost theory, Political Economic Approach, and Working partnership Approach are the theory foundation of the reasearch. Apparel franchise is a sample to analyse the hypothesis and correlation and multi-regression are a chief tools to estimate the hypothesis. Thus, the above results imply that a flexible governance is appropriate to consumer power, conflict is not intervening value between consumer power and channel governance, and the channel member's satisfaction can be confirmed in the flexible governance better than control governance.