• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.10
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• pp.67-74
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• 2007

Turbo code, a kind of channel coding technique, has ben used in the field of digital mobile communication system if the number of iterations is increased in the several channel environments, my further iteration results in very little improvement, and requires much delay and computation in proportion to the number of iterations. In this paper, it proposes an efficient stopping rules for the iteration process in turbo decoding. By using absolute mean values for the LLR difference values between the first and second decoder in the present decoding process, the proposed algorithm can largely reduce the average number of iterations without BER performance degradation in all SNR regions. As a result of simulation, the average number of iterations of proposed algorithm is reduced by about $18.25%{\sim}20.58%$ compared to SDR algerian in the lower SNR region, and is reduced by about $22.96%{\sim}28.74%$ compared to method using variance values of extrinsic information in the upper SNR region.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.946-948
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• 2005

H.264/AVC는 SoC/IEC MPEG와 ITU-T Video Coding Experts Group에서 함께 발표한 비디오 코딩을 위한 가장 최근의 표준이다. 기존의 표준들 보다 적은 비트로 높은 압축률과 좋은 화질을 제공하고 있다. 그러나 1/4 화소 움직임 예측과 보상의 지원과 7가지의 가변블록에 대한 움직임예측과 블록모드별 RD(Rate-Distortion)를 수행하고 CAVLC등 H.264/AVC 표준에서 채택한 여러 가지 비디오 압축방식으로 인해 그 복잡도가 훨씬 증가하였다. 이 논문에서 H.264/AVC의 복호화기에서 복잡도의 약 $40\%$ 이상을 차지하는 움직임보상 모듈을 효율적으로 수행하고 최적화하기 위한 방법을 제안한다. 예측된 모션벡터에 따라 창조하는 프레임에서 매크로블록을 만들어 내는 움직임 보상 과정을 수행하는 데 있어서 접근 지연시간이 큰 외부 메모리 창조를 선인출 메커니즘을 이용하여 미리 예측하여 수행함으로써 전체 수행시간을 줄이는 기법을 적용하였다. 이를 통하여 가변길이 복호화 모듈과 움직임 보상모듈을 수정하여 반복적으로 읽고, 쓰기를 수행해야 하는 횟수를 줄였다. 실험 결과 본 논문에서 제안하는 방법을 이용하여 복호화 과정을 수행했을 때 PSNR(Peak Signal to Noise Ratio)의 손실은 전혀 없으면서 복호화기의 전체 실행시간을 약 $5\%$ 향상시키고, 핵심 모듈인 움직임 보상과정에서 약 $20\%$ 정도 실행시간을 향상시키는 등 높은 성능 향상을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.215-218
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• 2007

모바일 환경에서는 상향링크와 하향링크의 대역폭이 비대칭적이며 전력이 한정되어 있기 때문에 효율적인 데이터 전송기술로 브로드캐스팅 방법이 연구되어 왔다. 브로드캐스트에서 인덱스를 사용하면 원하는 데이터가 언제 방송되는지를 알 수 있어 튜닝 시간을 줄이고, 전력의 소비를 줄이는 효과가 있다. 지금까지 연구된 싱글 채널 인덱스 기법들은 모든 데이터 아이템이 동일한 확률로 접근되는 flat 브로드캐스트 방송에 적합한 인덱스 기법들이다. 데이터 아이템에 대한 접근 확률이 편향되는 경우에는 멀티디스크 방송 기법을 사용해야 효과적이지만, 기존의 인덱스 기법들은 인덱스가 한 방송 주기 내에서 반복되어 방송되는 데이터 아이템을 가리킬 수 없기 때문에 멀티디스크 방송 기법에는 효과적이지 않다. 본 논문에서는 싱글 채널 인덱스 기법으로서 멀티디스크 방송에 적용되는 인덱스 기법인 MDEI (Multi-disk Exponential Index) 기법을 제안한다. 제안 하는 MDEI 기법은 각 디스크 별로 인덱스를 구성하기 때문에 데이터에 대한 접근확률이 편향되는 경우에 멀티디스크 방송을 기반으로 이 인덱스 기법을 사용하면 flat 브로드캐스트를 사용하는 다른 인덱스 기법을 사용했을 때보다 평균 접근지연시간 시간을 크게 줄일 수 있다. 실험 결과는 데이터에 대한 접근 확률이 편향된 환경에서 MDEI가 평균 접근지연시간에 있어서 매우 좋은 성능을 갖는 것을 보여준다.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.409-417
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• 2016

The purpose of this study was to demonstrate the effect on the degree of fatigue and accuracy of cardiopulmonary resuscitation according to the different time delays (3 minutes, 4 minutes). Carrying out repeated measures of variance (repeated ANOVA), we have shown that time effect (F = 7.835, p <.01) and group effect (F = 8.695, p<.01) and the interaction effect between time and group (F = 12.582, p<.001) were all statistically significant. It means, in the test of the main effect of group and time (3 minutes, 4 minutes) using the Bonferroni method, it turned out that the amount of lactic acid of the experimental group was larger than that of the control group (p<.01), and there was no difference until 3 minutes, but the difference of the amount of lactic acid was shown between before the experiment and after 4 minutes, and between 3 minutes and 4 minutes (p <.05), respectively. Then, in the result of the corresponding sample t-test, for comparing the according to the measurement time, the accuracy after 3 minutes became higher than the case of 4 minutes (t = 4.584, p <.001). Therefore, before 119 arrives performing cardiopulmonary resuscitation for emergency, rescuers need to perform cardiopulmonary resuscitation alternating with others before 3 minutes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.149-157
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• 2006

Turbo code, a kind of error correction coding technique, has been used in the field of digital mobile communication system. As the number of iterations increases, it can achieves remarkable BER performance over AWGN channel environment. However, if the number of iterations is increased in the several channel environments, any further iteration results in very little improvement, and requires much delay and computation in proportion to the number of iterations. To solve this problems, it is necessary to device an efficient criterion to stop the iteration process and prevent unnecessary delay and computation. In this paper, it proposes an efficient and simple criterion for stopping the iteration process in turbo decoding. By using variance values of LLR in turbo decoder, the proposed algerian can largely reduce the average number of iterations without BER performance degradation in all SNR regions. As a result of simulation, the average number of iterations in the upper SNR region is reduced by about $34.66%{\sim}41.33%$ compared to method using variance values of extrinsic information. the average number of iterations in the lower SNR region is reduced by about $13.93%{\sim}14.45%$ compared to CE algorithm and about $13.23%{\sim}14.26%$ compared to SDR algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.143-149
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• 2006

Turbo code, a kind of error correction coding technique, has been used in the field of digital mobile communication system. As the number of iterations increases, it can achieves remarkable BER performance over AWGN channel environment. However, if the number of iterations is increased in the several channel environments, any further iteration results in very little improvement, and requires much delay and computation in proportion to the number of iterations. To solve this problems, it is necessary to device an efficient criterion to stop the iteration process and prevent unnecessary delay and computation. In this paper, it proposes an efficient and simple criterion for stopping the iteration process in turbo decoding. By using sign changed ratio of extrinsic information values in turbo decoder, the proposed algorithm can largely reduce the average number of iterations without BER performance degradation. As a result of simulations, the average number of iterations is reduced by about $12.48%{\sim}22.22%$ compared to CE algorithm and about $20.43%{\sim}54.02%$ compared to SDR algorithm.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.60-65
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• 2000

Biosorptions of Cr and Pb were evaluated for 23 species of marine algae collected from a Korean coast. Among a variety of species for biosorbent potential, Sargassum species showed higher uptake capacity for Cr and Pb. An adsorption equilibrium was reached in about 1 hr for Cr and 30 min for Pb. The maximum uptake capacity was136.0 mg Cr/g biomass and 232.5 mg Pb/g biomass, respectively. In Pb biosorption in the column packed with Sargassum tbunbertii, 300 and 200 bed Tolumes at the concentration of 50 mg/L in feed solution were processed at the column residence time of 5 and 10 min before the column breakthrough point occurred. The elutions with 0.1 M HCl solution were more than $95{\%}$. The high efficiency of continous biesorntion and elution (3 cycles) indicated that Sargassum thunbergii was an effective biosorbent for Pb recovery.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.3
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• pp.71-80
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• 2021

The selection of an appropriate neural network algorithm is an important step for accurate data prediction in machine learning. Many algorithms based on basic artificial neural networks have been devised to efficiently predict future data. These networks include deep neural networks (DNNs), recurrent neural networks (RNNs), long short-term memory (LSTM) networks, and gated recurrent unit (GRU) neural networks. Developers face difficulties when choosing among these networks because sufficient information on their performance is unavailable. To alleviate this difficulty, we evaluated the performance of each algorithm by comparing their errors and processing times. Each neural network model was trained using a tax dataset, and the trained model was used for data prediction to compare accuracies among the various algorithms. Furthermore, the effects of activation functions and various optimizers on the performance of the models were analyzed The experimental results show that the GRU and LSTM algorithms yields the lowest prediction error with an average RMSE of 0.12 and an average R2 score of 0.78 and 0.75 respectively, and the basic DNN model achieves the lowest processing time but highest average RMSE of 0.163. Furthermore, the Adam optimizer yields the best performance (with DNN, GRU, and LSTM) in terms of error and the worst performance in terms of processing time. The findings of this study are thus expected to be useful for scientists and developers.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.757-768
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• 2002

These study were conducted to determine the effects of a whole or steam-flaked corn based diet on rumen microbial fermentation in vitro and ruminal metabolism in the Korean Native Goat(KNG) in vivo. The experiments consisted of two dietary treatments: control, steam-flaked corn(SFC) based diet(80%) + rice straw mixed(20%)(SFCR); 100% whole corn based diet(WC). The first experiment was conducted to investigate the effect of whole corn on ruminal metabolism in vitro for 0 to 48 h. pH values were optimally maintained during incubation time, and were not significantly different between treatments. Gas production of SFCR was significantly higher than WC(p<0.01). $NH_3$-N concentration tended to increase for WC, but not significantly different between treatments. The mean value of total volatile fatty acid concentration of WC was significantly lower than SFCR(p<0.01), but SFCR and WC linearly increased as the time of incubation approached 48 h. Mean value of acetate concentration of SFCR was significantly higher than WC(p<0.01). Propionate concentration of WC for the total incubation time was significantly higher than SFCR(p<0.01). The digestibility of dry matter was not significantly different between treatments, but SFCR was somewhat higher than WC. The second experiment was conducted to effect of whole shelled corn based diet on rumen metabolism in KNG. pH values tended to decrease through all treatments. There was not a significantly difference between treatments. Microbial protein yield of SFCR was significantly higher than WC(p<0.01). $NH_3$-N concentration of WC was significantly (p<0.01) higher than SFCR. Total VFA and propionate concentration of WC was significantly higher than SFCR(p<0.01), but acetate concentrate of WC was not significantly higher than SFCR. The mean value of total lactate concentration was significantly(p<0.01) different but the value of SFCR and WC were lower than the average concentration of acidosis. In sacco DM disappearance rate of SFC was significantly(p<0.01) higher than WC.

• Korean Journal of Cognitive Science
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• v.21 no.2
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• pp.253-282
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• 2010

Two experiments were conducted to explore the effects of anaphora and demonstrative ellipsis on reference resolution. This study assumed that two type of ellipsis could be sensitive to antecedents' saliency: the reverse typicality and mention order of antecedents. The muti-task approach measured the antecedent's activation level and processing load for the conflict resolution of theories of anaphoric resolution. In Experiment 1, using ellipsis for anaphora, participants read a series of sentence pairs by self-paced and performed a probe recognition test. The results showed the main effects of antecedent's typicality and mention order in both tasks. In Experiment 2, using noun phrase without demonstrative for anaphora, participants read a series of sentence pairs by self-paced and performed a probe recognition test. The results showed main effects of mention order of antecedents for probe recognition task only. The first antecedent was recognized faster than the second one. The results of two experiments suggested that anaphora type and antecedent's saliency were dynamically interact in reference resolution for Korean.