• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.3 s.303
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• pp.1-8
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• 2005

At IETF (Internet Engineering Task Force), recently RFC3775, RFC3776 documents about the mobile IPv6 were standardized by IETF (Internet Engineering Task Force). Those specifications propose that during the roaming, the mobile node sends securely the binding update to the home agent and the correspondent node after setting the security association between Mobile Node and Home Agent. But there is no secure bootstrapping method between a mobile node and a home agent at the two RFC documents. This paper proposed a method for the secure bootstrapping between a mobile node and a home agent. This makes the authentication, binding update, home agent assignment, security association distribution through the AAA-based secure channel between mobile node and home agent. And the proposed method was analyzed in the view of the procedure, round trip and security strength.

• Phonetics and Speech Sciences
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• v.10 no.1
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• pp.33-38
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• 2018

Although deep neural network-based acoustic models have greatly improved the performance of automatic speech recognition (ASR), reverberation still degrades the performance of distant speech recognition in indoor environments. In this paper, we adopt the DenseNet, which has shown great performance results in image classification tasks, to improve the performance of reverberant speech recognition. The DenseNet enables the deep convolutional neural network (CNN) to be effectively trained by concatenating feature maps in each convolutional layer. In addition, we extend the concept of multi-resolution CNN to multi-resolution DenseNet for robust speech recognition in reverberant environments. We evaluate the performance of reverberant speech recognition on the single-channel ASR task in reverberant voice enhancement and recognition benchmark (REVERB) challenge 2014. According to the experimental results, the DenseNet-based acoustic models show better performance than do the conventional CNN-based ones, and the multi-resolution DenseNet provides additional performance improvement.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.47-52
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• 2010

The low power of ultra-wideband (UWB) signal makes the acquisition of UWB signal be a more challenging task. In this paper, we propose the method of high order template signal technique that reduces the synchronization time. Experimental results are presented to show the improvements of performance in the mean acquisition time (MAT) and the probability of detection. The performance compared with the serial search, the truly random search and the random permutation search. It is shown that over typical UWB multipath channels, a random permutation search scheme may yield lower MAT than serial search.

• Journal of Distribution Research
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• v.9 no.1
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• pp.1-24
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• 2004

As the dot-com companies realize the importance of the traditional business operations such as product distribution and sourcing, the task of balancing business strategy and operations between electronic commerce and"bricks St mortar"channels is an ongoing challenge. However, there are no generic recipes for formulating business strategy that optimally bridges the physical and virtual operations. In order to provide some guidelines, this study examines the big 3 retailers in Korea, and their"clicks ＆ mortar"strategy, assessing how the activities of each channel are integrated to achieve the synergy effect. This study analyzes the differences in the pattern of integration among the three retailers and traces the causes of those differences. It also figures out the relationship between the degree of integration and performance variables such as growth and cost. Finally. it defines the essential constraints on the process of integration along with managerial implications.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.1
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• pp.20-27
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• 2010

Modeling is essential to simulate the operation of integrated circuit (IC) before its fabrication. Seeing a large number of Metal-Oxide-Silicon Field-Effect-Transistor (MOSFET) models available, it has become important to understand them and compare them for their pros and cons. The task becomes equally difficult when the complexity of these models becomes very high. The paper reviews the mainstream models with their physical relevance and their comparisons. Major short-channel and quantum effects in the models are outlined. Emphasis is set upon the latest compact models like BSIM, MOS Models 9/11, EKV, SP etc.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.511-516
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• 2013

Bladder cancer is the seventh most common cancer in men that smoke, and the incidence of disease increases with age. The mechanism of occurrence has not yet been established. Potassium channels have been linked with cell proliferation. Some two-pore domain $K^+$ channels (K2P), such as TASK3 and TREK1, have recently been shown to be overexpressed in cancer cells. Here we focused on the relationship between cell growth and the mechanosensitive K2P channel, TREK2, in the human bladder cancer cell line, 253J. We confirmed that TREK2 was expressed in bladder cancer cell lines by Western blot and quantitative real-time PCR. Using the patch-clamp technique, the mechanosensitive TREK2 channel was recorded in the presence of symmetrical 150 mM KCl solutions. In 253J cells, the TREK2 channel was activated by polyunsaturated fatty acids, intracellular acidosis at -60 mV and mechanical stretch at -40 mV or 40 mV. Furthermore, small interfering RNA (siRNA)-mediated TREK2 knockdown resulted in a slight depolarization from $-19.9mV{\pm}0.8$ (n=116) to $-8.5mV{\pm}1.4$ (n=74) and decreased proliferation of 253J cells, compared to negative control siRNA. 253J cells treated with TREK2 siRNA showed a significant increase in the expression of cell cycle boundary proteins p21 and p53 and also a remarkable decrease in protein expression of cyclins D1 and D3. Taken together, the TREK2 channel is present in bladder cancer cell lines and may, at least in part, contribute to cell cycle-dependent growth.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.2
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• pp.122-129
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• 2019

Predicting heat transfer from the inner wall of the combustion chamber of the liquid rocket is a very difficult task. Several complex processes, such as convection, radiation and conduction must be taken into consideration. Usually commercial programs are used for the analysis of this processes. However, commercial programs are not a perfect solution, because of the long calculation times and a burdening data-input work. In this study, we developed and implemented one - dimensional thermal analysis. This technique can be easily used on the initial stage. The design of the combustion chamber's cooling channel of the steam generator designed using developed technique. In order to compare experimental and theoretical data, the combustion test was performed. Obtained experimental data for the coolant temperature differ from the theoretical prediction by only 8.5%.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.1
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• pp.52-74
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• 1989

In general, the state of system can be effected by external noise and observed only through a noisy channel. Therefore we use the estimation technigue for the information of state of the system effected by noise. There are many filters such as kalman-Buchy filter, kalman filter, Extended Kalman filter algorithm, cononlinear, extended Kalman filter algorithm to the estimation of parameters is very useful and has a long history. Also a considerable number of applications of this method has been reported. In this paper, the robot control system is treated in stochastic optimal control because of the robots doing a complicated and accurate task in inapproate environment. We have conclusion that error covariance is converged and the stability of filtering is obtained.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.6-16
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• 2008

An instable wireless channel condition causes more packet losses and retransmissions due to interference, fading, station mobility, and so on. Therefore video streaming service over a wireless networks is a challenging task because of the changes in the wireless channel conditions and time-constraints characteristics of the video streaming services. To provide efficient video streaming over a wireless networks, QoS-enhanced MAC protocol, IEEE 802.11e, is standardized recently. Tn this paper, we propose a new network-adaptive H.264 video streaming mechanism in the IEEE 802.11e wireless networks. To improve the quality of video streaming services, video stream has to adapt to the changes in the wireless channel conditions. The wireless channel conditions are estimated by the packet loss probability and informed to the application layer by the cross-layering. According to the wireless channel information, the video streaming application filters out the low-priority data. This adaptation mechanism efficiently uses system resources because it drops the low-priority data in advance. Therefore, our cross-layer design can provide improved video streaming services to the end-user. Through the implementation and performance evaluation, we prove that the proposed mechanism improves the QoS of the video streaming by providing the smoothed playback.

• Publications of The Korean Astronomical Society
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• v.28 no.1
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• pp.7-13
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• 2013

We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the 'background' task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using 'background' task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.