• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.201-210
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• 2023

Deep learning-based face verificattion model show high performance and are used in many fields, but there is a possibility the user's face image may be leaked in the process of inputting the face image to the model. Althoughde-identification technology exists as a method for minimizing the exposure of face features, there is a problemin that verification performance decreases when the existing technology is applied. In this paper, after combining the face features of other person, a de-identified face image is created through StyleGAN. In addition, we propose a method of optimizingthe combining ratio of features according to the face verification model using HopSkipJumpAttack. We visualize the images generated by the proposed method to check the de-identification performance, and evaluate the ability to maintain the performance of the face verification model through experiments. That is, face verification can be performed using the de-identified image generated through the proposed method, and leakage of face personal information can be prevented.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.498-512
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• 2010

Intra coding is an indispensable coding tool since it can provide random accessibility as well as error resiliency. However, it is the problem that intra coding has relatively low coding efficiency compared with inter coding in the area of video coding. Even though H.264/AVC has significantly improved the intra coding performance compared with previous video standards, H.264/AVC encoder complexity is significantly increased, which is not suitable for low bit rate interactive services. In this paper, a Voting-based Intra Mode Bit Skip (V-IMBS) scheme is proposed to improve coding efficiency as well as to reduce encoding time complexity using decoder-side prediction. In case that the decoder can determine the same prediction mode as what is chosen by the encoder, the encoder does not send that intra prediction mode; otherwise, the conventional H.264/AVC intra coding is performed. Simulation results reveal a performance increase up to 4.44% overall rate savings and 0.24 dB in peak signal-to-noise ratio while the frame encoding speed of proposed method is about 42.8% better than that of H.264/AVC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.1976-1985
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• 2015

The amount of packets in palyout buffer of video streaming receiver can be changed by network condition, and saturated and exhausted by the delay and jitter. Especially, if the amount of incoming video traffic exceeds the maximum allowed playout buffer, buffer overflow problem can be generated. It makes the deterioration of video image and the discontinuity of playout by skip phenomenon. Also, if the incoming packets are delayed by network confusion, the stop phenomenon of video image is made by buffering due to buffer underflow problem. To solve these problems, this paper proposes the video streaming receiver with token bucket scheme which automatically establishes the important parameters like token generation rate r and bucket maximum capacity c adapting to the pattern of video packets. The simulation results using network simulator-2 (NS-2) and joint scalable video model (JSVM) show that the proposed token bucket scheme with automatic establishment parameter provides better performance than the existing token bucket scheme with manual establishment parameter in terms of the generation number of overflow and underflow, packer loss rate, and peak signal to noise ratio (PSNR) in three test video sequences.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.66-75
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• 1999

In two-stroke engines, methods of evaluating scavenging effciency have been studied in parallel with trials for improvement of scavenging process. But simulating methods have a wide difference with difference with scavenging process in real engines and methods of evaluating scavening efficiency in real engines are very difficult and very expensive. This study shows that there is a possbility of evaluating scavenging efficiency in real engines very easily by analysis of in-cylinder pressure data. And as a characteristics two-stroke engines, the poly tropic indices in the process of compression are varies with degreeof scavenging and good representatives of scavenging efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.342-351
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• 2008

In this paper, a new handover procedure for OFDM-based multi-hop relay systems is proposed to reduce the handover overhead by distinguishing inter-cell handover event from intra-cell handover event at the level of physical layer using a hierarchical design concept of preamble. A Subcell ID concept for identifying RS in a cell is proposed in the design of hierarchical manner, in addition to the existing Cell ID for identifying BS. The decision on either inter-cell handover or intra-cell handover is made by the signal quality measure of CBINR(Carrier of BS to Interference and Noise Ratio) and CRINR(Carrier of RS to Interference and Noise Ratio), provided by the hierarchical preamble. The proposed handover procedure can simplify scanning procedure and skip/simplify network re-entry procedure (capability negotiation, authorization, registration), resulting in a significant reduction of handover overhead.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.448-461
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• 2011

H.264/AVC significantly outperforms the previous video coding standards with many new coding tools. Among these tools, several intra-block coding tools can particularly improve coding efficiency. For intra prediction, H.264/AVC supports most probable mode in the entropy coding process to reduce syntax elements indicating intra prediction modes and most probable mode selection ratio is very high. Also, in general, natural images and videos have many homogeneous regions whose high correlation with neighbouring blocks. In this paper, we propose intra prediction mode SKIP mode using decoder-side prediction to improve the coding efficiency. The proposed method is determined the optimal prediction mode using only neighbouring block's information and coded on the basis of the conventional prediction/transform coding. And the prediction modes are not send to decoder at all. Skipped intra prediction mode is determined by decoder. Experimental results show that the proposed method achieves coding gains of 1.40% for common intermediate format(CIF), 3.24% for 720p sequences against the H.264/AVC JM 17.0 reference software.

• Journal of Korean Medicine for Obesity Research
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• v.14 no.1
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• pp.29-35
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• 2014

Objectives: This study was to investigate how body-shape perception could influence to weight control practice both in normal and obese group. Methods: We used 2012 Korea National Health and Nutrition Examination Survey to analysis 1) weight control practices of population; 2) consistency between body-shape perception and body mass index; 3) comparison weight control practices between normal group and body mass index (BMI) obese group in perceptional obese group; 4) odds ratio of BMI obese group using herbal drugs for weight control practice in perceptional obese group. Results: We found that study population tends to choose exercise, dietary restriction, meal skip, health functional food, one-food, drug, herbal drug, fasting and self-medication in order of frequency to control weight. The agreement between body-shape perception and BMI within obese group was approximately 64% with 0.40 of Cohen's Kappa coefficient, ranging from 0.384 to 0.423. Within perceptional obese group, choosing each weight control practice methods ratios between normal BMI group and obese BMI group were not significantly different. Within perceptional obese group, obese BMI group showed significant odds ratio (2.58, 95% confidence intervals, 1.38~4.85) than normal BMI group in choosing herbal medication for weight loss when adjusting other variables. Conclusions: We concluded that body-shape perception might be an important factor for choosing weight control program, and roles of Korean medical doctors thought to be enhanced for using herbal medication for weight loss.

• Journal of IKEEE
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• v.5 no.1 s.8
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• pp.111-120
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• 2001

VC merging involves distinguishing cells from an identical merged VC label. Various approaches have been proposed to help this identification process. However, most of them incur additional buffering, protocol overhead and/or variable delay. They make the provision of QoS difficult to achieve. So it was proposed a merge capable scheduler to support VC-merging (VCMS). However, in situations where all VCs are to be merged or the incoming traffic load is very low, it could happen that there are not enough non-merging cells to snoop. In this situation the scheduler uses special control cells to fill the empty time slots out. Too many control cells can cause high cell loss ratio and an additional packet transfer delay. To overcome the drawbacks, we propose a Sequence Skipping(SS) method where the sequencers skip the empty queues and insert SS cells. We show SS method is suitable for VC-merging and can reduce the cell loss ratio and the mean packet transfer delay through simulations.

• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.598-605
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• 2009

This study was investigated to examine the dietary habits and satisfaction with a school lunch program for high school boys and girls. The survey was conducted on 416 students(208 boys and 208 girls) using questionnaire. Overall, 40.1% of the respondents reported that they skip breakfast, and more girls skipped breakfast than boys(p<0.05). The major reason for skipping meal was 'no enough time'(48.3%) and duration of meal appeared the highest ratio in '10~15 minutes'(51.7%) and boys having meal with 10 minutes were significantly higher than girls(p<0.001). When asked if they have an unbalanced diet, 58.8% responded "little bit do it but it depends on food". Vegetables were the foods most absent from an unbalanced diet. Additionally, 90% of all respondents takes a snack a day, and 21.5% of the respondents reported that snacks were the most preferable meals. In terms of a satisfaction with school meals, 70.6% of the respondents reported that they were "unsatisfied". Additionally, 43.5% of the students reported that they did not finish their soup. Moreover, 57.5% of the students reported that they were dissatisfied because that food was "not tasty". Based on the results of this study, the meal habits of the students were determined by various factors including gender. To ensure that boys and girls receive the proper nutrition, development of proper eating habits through school meals, nutrition education and a guidance during meal service should be achieved.

• Journal of Korea Multimedia Society
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• v.15 no.9
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• pp.1086-1092
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• 2012

In this paper, we propose the rate control scheme reducing frame skipping at low bit-rate. As the method considering lossy parts in the compressing process at the existing scheme, the proposed scheme is improved by subtracting the converted bits from the target bit-rate of the current frame. The converted bits are the value resulted from multiplying the ratio of the current frame MAD to the previous frame MAD by the compressed bits changed from the remaining values after compressing the previous frame.