• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.83-90
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• 2007

Flow theory has been borrowed from psychology to address positive user experiences with computers and Internet. The flow experience in computer-mediated environment (CME) has been correlated to increased communication, loaming, exploratory behavior and positive affect. A comparative experiment between CME and traditional paper-pencil environment was conducted to verify whether particular environments or interfaces are more conducive to yielding flow among users. The results showed that there were no differences in flow dimensions except 'enjoyment' between CME and paper-pencil environment. But the distorted senses of time among users were significantly different between the media environments.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.102-107
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• 2007

Since the Matrix Pencil (MP) method can be performed to estimate multiple DOAs by using only single snapshot, this method is suitable for short data length or when the environment is dynamic. As the number of array increases, the computational load increases due to complex number computation. This paper presents an approach based on a unitary matrix pencil (MP) algorithm to reduce the computational load. Unitary transformation for the MP method has been suggested and formulated successfully. The computer simulation shows that the error rate of proposed method agree with that of MP for different SNR values.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8A
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• pp.741-747
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• 2011

Matrix Pencil method is one of the promising method to estimate DOA in non-stationary, multi-path coherent environment. Not only the Matrix Pencil Method offers better resolution than the conventional approach using covariance matrix, but also it is computationally very efficient. In this paper, we presented an effect of unbalanced data weighting in the formulation of the Matrix Pencil method. A new formulation has been suggested to mitigate the effect of unbalanced data weighting. Numerical simulation demonstrated that the proposed method can successfully eliminate the problem of unbalanced data weighting.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.3
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• pp.135-144
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• 2002

The purpose of this study is to examine the effects of computer-based creativity training. Four groups of vocational high school students totaling 151 were used as experimental subjects. Two dimensions of treatment were designed. One treatment dimension is the use of computer medium in education： computer based vs. paper-pencil setting of education. The second treatment dimension is the method of creativity training: technique-oriented training program vs. factor-oriented training program. Both a pretest and a post-test were administered to all participated students. The tests were composed of a Creative Figural Test and a Creative Product Test. After the pretest 8 sessions of creative training were delivered as intended in the design of the experiment. The Dost-test was arranged a week after the completion of the training sessions. The results of the study include： First, all the 4 groups showed certain amount of improvements in their scores of Creative Figural Test, while no improvements was observed in the creative product test score. Second, the technique-oriented creativity training was more effective than the factor-oriented under the context of computer-based education, and the factor-oriented training was more effective in the paper-pencil setting. The results suggest that different pedagogical approaches should be employed for computer-based training as compared to the paper-pencil education.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.782-790
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• 2014

In this paper, we apply the 2-D Matrix Pencil Method(MPM) to the estimation of the direction of arrival(DOA) of multiple signals of interest(SOIs) in bistatic MIMO radar. The 2-D MPM shows remarkable performance under a low SNR environment and low computational complexity to estimate the DOA of multiple SOIs. Also, it is possible to estimate the direction of departure(DOD) which is an angle from transmitter to target. To verify the proposed algorithm, we applied the proposed algorithm to a uniformly spaced linear array(ULA) and compared the RMSE(Root Mean Square Error) of DOA and DOD under the various SNR with those of the 2-D Capon algorithm.

• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.511-516
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• 1994

Parameter estimation techniques are discussed for the complex frequency analysis of an electromagnetic scatterer. The paper suggests how the Maximum Likelihood estimation technique can be applied for this purpose. Experiments on hypothetical data sets demonstrate that the Maximum Likelihood technique is better than the Pencil of Functions technique. Although there have been several techniques including MLE suggested as tools of the parameter estimation, the proposed method has strong advantages under the noise-contaminated sample data environment because it uses minimal dimension of system matrix that stands totally independent of the length of extracted data set.

• Journal of Educational Research in Mathematics
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• v.10 no.2
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• pp.279-300
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• 2000

This research investigated students' interaction in the environment with dynamic geometry software such as Cabri II, and GSP in order to understand and analyze why computer environment is a richer interaction field for developing children's explorative ability than other traditional paper-and-pencil environments. This research focused on 5th graders' interaction with topics of transformational geometry and similar figure and analyzed children's learning process and their interview results gotten through audio and video recording. Computer exploration with a dynamic software seems to be very helpful for elementary students to learn geometry. However, the effectiveness of the computer should be discussed with respected to its methodological validity of teachers to guide students' explorative activities with a dynamic software.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.93-100
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• 2004

In this paper, we describe the design, fabrication, and test results of a W-band FMCW radar for the metal target detection under the ground clutter environment. In order to detect metal targets on the ground, we used a single cassegrain antenna with the beamwidth of $1.45^{\circ}$ which forms pencil-beam footprint on the ground. A log envelope detector was applied to improve radar performance in the severe ground clutter known as Weibull and log normal clutter. The designed FMCW radar can acquire altitude information from the ground clutter with $\sigma_0=-23dB$ at the height of 160m. The fabricated W-band FMCW radar transmits 11 dBm power and the dynamic range of the receiver is from -106dBm to -30dBm. The performances of the fabricated sensors were tested out in the fields and detected a car target of 200m apart on the grass.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.239-247
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• 2018

Adaptive Beamforming (ABF) algorithm, which is a typical jammer suppression algorithm, guarantees the performance on the assumption that the jamming characteristics of the TDS (Training Data Sample) are stationary, which are obtained immediately before and after transmitting the pulse signal. Therefore, effective jammer suppression can not be expected when the jamming characteristics are non-stationary. In this paper, we propose a new jammer suppression algorithm, of which power spectrum fluctuates fast. In this case, we assume that the location of the jammer station is fixed during the processing time. By applying the MPM (Matrix Pencil Method) to the jamming signal in TDS, we can estimate jammer parameters such as power and incident angle, of which the power will vary fast in time or range bins after TDS. Though we assume that the jammer station is fixed, the estimated jammer's incident angle has an error due to the noise, which degrades the performance of the jammer suppression as the jammer power increases fast. Therefore, the jammer's incident angle should be re-estimated at each range bin after TDS. By using the re-estimated jammer's incident angle, we can construct new covariance matrix under the non-stationary jamming environment. Then, the optimum weight for the jammer suppression is obtained by inversing matrix estimation method based on the matrix projection with the estimated jammer parameters as variables. To verify the performance of the proposed algorithm, the SINR (signal-to-interference plus noise ratio) loss of the proposed algorithm is compared with that of the conventional ABF algorithm.

• The Mathematical Education
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• v.53 no.2
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• pp.163-184
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• 2014

The purpose of this study was to develop the assessment tools using graphing calculators for the assessment of the mathematical process which was emphasized in 2009 reformed mathematics curriculum. In this paper, we presented three sample calculator-based test items for the assessment of students' mathematical process abilities and scoring rubrics for the paper and pencil assessment and assessment based on observation on each item. In order to improve mathematics teachers' understanding of the assessment tools using graphing calculators and to show the procedures of assessment using technological devices, we also drew up assessment guidelines. We hope the results of the study contribute to the promotion of assessment environment encouraging the use of graphing calculators in assessments.