• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1409-1413
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• 2013

This paper analyzed the change of subthreshold current for channel doping concentration of double gate(DG) MOSFET. Poisson's equation had been used to analyze the potential distribution in channel, and Gaussian function had been used as carrier distribution. The potential distribution was obtained as the analytical function of channel dimension, using the boundary condition. The subthreshold current had been analyzed for channel doping concentration, and projected range and standard projected deviation of Gaussian function. Since this analytical potential model was verified in the previous papers, we used this model to analyze the subthreshold current. As a result, we know the subthreshold current was influenced on parameters of Gaussian function and channel doping concentration for DGMOSFET.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1271-1278
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• 2020

Deep learning-based profiling side-channel analysis is a powerful analysis method that utilizes the neural network to profile the relationship between the side-channel information and the intermediate value. Since the neural network interprets each point of the signal in a different dimension, jitter makes it much hard that the neural network with dimension-wise weights learns the relationship. This paper shows that replacing the fully-connected layer of the traditional CNN (Convolutional Neural Network) with global average pooling (GAP) allows us to design the inherently robust neural network inherently for jitter. We experimented with the ChipWhisperer-Lite board to demonstrate the proposed method: as a result, the validation accuracy of the CNN with a fully-connected layer was only up to 1.4%; contrastively, the validation accuracy of the CNN with GAP was very high at up to 41.7%.

• Journal of Power System Engineering
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• v.17 no.1
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• pp.64-70
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• 2013

The heat transfer and friction factor characteristics of turbulent flows in three stationary channels have been investigated experimentally to check out the effect of divergence ratio. These are a constant cross-sectional channel and two diverging channels with ratio of divergence(Dho/Dhi) of 1.16 and 1.49. The measurement was conducted within the range of Reynolds numbers from 15,000 to 89,000 and the dimension of uniform cross-sectional test section is $100mm{\times}100mm$ at the cross section and 1,000 mm in length. The measurements of heat transfer coefficients and friction factors in the uniform channels were conducted as a reference. Because of the streamwise flow deceleration, the heat transfer and friction factor characteristics in the diverging channel were quite different from those of the constant cross-sectional channel. The effective friction factors and convective heat transfer coefficients increased with increasing the ratio of divergence of the channel.

• Korean Management Science Review
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• v.32 no.4
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• pp.135-153
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• 2015

In this paper, we intend to understand distinguishable SNS technology contributions for B2C commerce. In order to theorize this, we draw upon Technology-to-Performance chain (TPC) theory to develop the model that could explain how the technology value of the SNS could be realizable. For the purpose of capturing SNS technology effect to B2C channel effectiveness, on the basis of TPC theory, personal productivity is selected as a performance variable instead of satisfaction from SNS usage. Accordingly, as the antecedents of personal productivity, two variables of locatability and timeliness are extracted to reflect Task-technology-fit (TTF) dimension of performance precursors. For the utilization dimension of TPC framework, convenience and recreation tendency of the personal traits in shopping are included as the precursors of SNS utilization in the sense of reflecting utilitarian and hedonic value of SNS adoption. Empirical validation is conducted with reference to promotion and sales event on Facebook, which is chosen as the typical SNS based B2C commerce scenario. The data analysis result provide useful insights to further investigate the firm's SNS usage potentials for business applications.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.2 s.245
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• pp.157-163
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• 2006

Our research dealt with micro fabrication using micro forming process. The goal of the research was to establish the limit of forming process concerning the size of forming material and formed shape. Flat-rolled ultra thin metallic foils of pure copper(3.0 and $1.0{\mu}m$ in thickness)and stainless steel($2.5{\mu}m$ in thickness) were used for forming material. We obtained the various shapes of micro channels as using designed forming process. $12-14{\mu}m$ wide and $9{\mu}m$ deep channels were made on $3.0{\mu}m$ thick foil and $6{\mu}m$ wide and $3{\mu}m$deep channels were made on $1.0{\mu}m$ thick foil. Si wafer die for forming was fabricated by using etching technique. And the relation of etching time and die dimension was investigated for fabricating precisely die groove. For the forming, die and metal foil were vacuum packed and the forming was conducted with a cold isostatic press. The formed channels were examined in terms of their dimension, surface qualities and potential for defects. Base on the examinations, formability of ultra thin metallic foil was also discussed. Finally, we compared the forming result with simulation. The result of research showed that metal forming technology is promising to produce micro parts.

• Korean Journal of Acupuncture
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• v.20 no.3
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• pp.49-60
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• 2003

The aim of this study was to examine the effects of electroacupuncture(EA) at the PC6 (Naegwan) on normal humans using KarhunenLoeve decomposition method. Electroencephalogram(EEG) is a multi-scaled signal consisting of several components of time series with different dominant frequency ranges and different origins. EEG KarhunenLoeve decomposition method exibit site-specific and state-related differences in specific frequency bands. In this study, KarhunenLoeve decomposition method was used as a measure(D2) of complexity. 30 channel EEG study was carried out in 10 subjects (10 males; $age=21.4{\pm}0.5$ years). Results : We found that the average values and standard deviations of D2 at FP1, FP2, FTC1, FTC2, TT1, TT2, T4, TCP1, P3, P4, T6, OZ channel (p<0.05) were higher than during the acupuncture treatment, and the average values and standard deviations of D2 at F3, F8 channels(p<0.05) were lowered than during the acupuncture treatment. However, the comparison with that before and after the treatment shows no significant differences in all channels.

• Journal of The Korean Astronomical Society
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• v.41 no.6
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• pp.157-161
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• 2008

We have estimated the fractal dimension of the molecular clouds associated with the Hii region Sh 156 in the Outer Galaxy. We selected the $^{12}CO$ cube data from the FCRAO CO Survey of the Outer Galaxy. Using a developed code within IRAF, we identified slice-clouds (2-dimensional clouds in velocity-channel maps) with two threshold temperatures to estimate the fractal dimension. With the threshold temperatures of 1.8 K, and 3 K, we identified 317 slice-clouds and 217 slice-clouds, respectively. There seems to be a turn-over location in fractional dimension slope around NP (area; number of pixel) = 40. The fractal dimensions was estimated to be D = $1.5\;{\sim}\;1.53$ for $NP\;{\geq}\;40$, where $P\;{\propto}\;A^{D/2}$ (P is perimeter and A is area), which is slightly larger than other results. The sampling rate (spatial resolution) of observed data must be an important parameter when estimating fractal dimension. Fractal dimension is apparently invariant when varying the threshold temperatures applied to slice-clouds identification.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.475-479
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• 2010

The clipping value, defined as the log-likelihood ratio (LLR) in the case wherein all the list of candidates have the same binary value, is investigated, and an effective method to estimate it is presented for iterative tree search detection. The basic principle behind the method is that the clipping value of a channel bit is equal to the LLR of the maximum probability of correct decision of the bit to the corresponding probability of erroneous decision. In conjunction with multilevel bit mappings, the clipping value can be calculated with the parameters of the number of transmit antennas, $N_t$; number of bits per constellation point, $M_c$; and variance of the channel noise, $\sigma^2$, per real dimension in the Rayleigh fading channel. Analyses and simulations show that the bit error performance of the proposed method is better than that of the conventional fixed-value method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4759-4780
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• 2017

Full Dimension multiple input multiple output (FD-MIMO) architecture employs a planar array design at the Base Station (BS) to provide high order multi-user MIMO (MU-MIMO) via simultaneous data transmission to large number of users. With FD-MIMO, the BS can also adjust the beam direction in both elevation and azimuth direction to concentrate the energy on the user of interests while minimizing the interference leakage to co-scheduled users in the same cell or users in the neighboring cells. In a typical highly populated macrocell environment, modelling the elevation angular characteristics of three-dimensional (3D) channel is critical to understanding the performance limits of the FD-MIMO system. In this paper, we study the throughput performance of FD-MIMO system with varying elevation angular spread and inter-element spacing using a 3D spatial channel model. Our results show that for a typical urban scenario, horizontal beamforming with correlated antenna spacing achieves optimal performance but by restricting the spread of elevation angles of departure, elevation beamforming achieves high array gain with wide inter-element spacing. We also realize significant gains due to spatial array processing via modelling the elevation domain and varying the inter-element spacing for both the transmitter and receiver.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.350-350
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• 2010

Silicon carbide (SiC), one of the well known wide band gap semiconductors, shows high thermal conductivities, chemical inertness and breakdown energies. The design of normally-off 4H-SiC VJFETs [1] has been reported and 4H-SiC VJFETs with different lateral JFET channel opening dimensions have been studied [2]. In this work, 4H-SiC based VJFETs has been designed using the device simulator (ATLAS, Silvaco Data System, Inc). We varied the n-epi layer thickness (from $6\;{\mu}m$ to $10\;{\mu}m$) and the channel width (from $0.9\;{\mu}m$ to $1.2\;{\mu}m$), and investigated the static characteristics as blocking voltages, threshold voltages, on-resistances. We have shown that silicon carbide JFET structures of highly intensified blocking voltages with optimized figures of merit can thus be achieved by adjusting the epi layer thickness and channel width.