• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.8
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• pp.1-6
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• 2011

In this paper, another analytical approach for dual-hop amplify-and-forward(AF) relay systems is proposed over Rayleigh fading channels. Previous approaches derived the moment generating function(MGF) by using the cumulative distribution function(CDF) or probability density function(PDF) of the received signal-to-noise ratio(SNR) for source-relay-destination(S-R-D) link. Then, the average symbol error rate is expressed based on derived MGFs. In this paper, another new approach is proposed. It means that the MGF is directly derived by utilizing PDFs of both source-relay(S-R) and relay-destination(R-D) links. Additionary, the newly derived MGF is compared and analyzed with previous ones. Furthermore, simulation results are presented to validate the accuracy of proposed analytical expression. Based on this, it is confirmed that the proposed analytical approach can be a another solution for dual-hop AF relay systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.1047-1054
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• 2012

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, and its risk increases with age. Conventionally, the way of detecting AF was the time·frequency domain analysis of RR variability. However, the detection of ECG signal is difficult because of the low amplitude of the P wave and the corruption by the noise. Also, the time·frequency domain analysis of RR variability has disadvantage to get the details of irregular RR interval rhythm. In this study, we describe an atrial fibrillation pattern analysis based on symbolization and information entropy. We transformed RR interval data into symbolic sequence through differential partition, analyzed RR interval pattern, quantified the complexity through Shannon entropy and detected atrial fibrillation. The detection algorithm was tested using the threshold between 10ms and 100ms on two databases, namely the MIT-BIH Atrial Fibrillation Database.

• Electronics and Telecommunications Trends
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• v.23 no.3
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• pp.106-118
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• 2008

본 고에서는 최근 표준화가 완료된 MPEG-A(ISO/IEC 23000) Part 9 DMB-AF의 표준화 배경 및 서비스 모델을 소개하고 기술적인 구성요소에 대해 설명한다. DMB-AF는 MPEG-4 Part 12 ISO Base Media File Format에 기반한 DMB 콘텐트 전용 파일 포맷으로, 다양한 종류의 지상파 DMB 및 위성 DMB 콘텐트를 체계적으로 표현하고 효과적으로 저장 및 접근하며 안전하게 보호/유통하기 위한 기술들이 포함되어 있다. 이러한 DMB-AF 표준은 다양한 DMB 콘텐트들을 적절히 연계하여 방통융합 환경에서 다양한 비즈니스 기회를 창출할 수 있는 공통의 프레임워크를 제공할 뿐 아니라, 저장매체를 매개로 하여 사용자가 원하는 시점에 원하는 프로그램을 원하는 장치에서 시청할 수 있도록 하는 DMB-Anytime 서비스를 가능하게 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.31-36
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• 2012

In this paper, we proposed spectrum sensing using cooperative relay to solve problem of sensing performance degradation due to CPE (Customer-Premises equipments) which causes low SNR (signal-to-noise ratio) problem. In cooperative communication system, AF (amplify-and-forward) and DF (decoded-and-forward) is widely used for relay mechanism. Also, it is expected that cooperative relay scheme guarantees the high sensing performance by its diversity gain. Based on these backgrounds, in this paper, we apply to cooperative relay scheme to the CR (Cognitive Radio) system, and simulation results show comparison of the sensing performance.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.364-367
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• 2009

The role of the low voltage circuit breakers that are installed just before the load is very important for safety. This paper presents a test and analysis of the instantaneous trip characteristics of the Low Voltage 30AF(Ampere Frame) Circuit Breakers, which can be expected to be used for improving the safety of the Low Voltage Circuit Breaker.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2317-2323
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• 2015

In this paper, we analyze the performance of dual-hop amplify-and-forward (AF) relaying in cooperative networks with partial relay selection. An AF relay gain considered in this paper includes channel-noise-assisted relay gain. Leveraging a received signal-to-noise ratio (SNR) model, we derive exact closed-form expressions for the probability density function (pdf) and cumulative distribution function (cdf) of the end-to-end SNR. Moreover, an exact closed-form expression of the ergodic capacity for dual-hop AF relaying with channel-noise-assisted relay gain and partial relay selection is investigated. The analytical results shown in this paper are confirmed by Monte-Carlo simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.487-494
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• 2010

This paper presents an OFDM-based dual-hop multi-relay system with best relay selection maximizing the mutual information. For the system either with decode-and-forward (DF) relays or with amplify-and-forward (AF) relays, we derive a lower-bound on the outage probability and the diversity order achievable in frequency selective fading channels and provide the outage capacity from simulation. Performance evaluation shows that both DF and AF provide the same diversity order as in the lower-bound but DF of which the outage probability is much closer to the lower-bound provides a better outage capacity than AF. It is also observed that the SNR gain of DF over AF gets larger as either the number of resolvable multipaths or the number of relay candidates increases, which makes DF relaying more favorable to the OFDM-based multi-relay system.

• The KIPS Transactions:PartD
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• v.14D no.5
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• pp.483-490
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• 2007

Recently mining techniques that analyze the data stream to discover potential information, have been widely studied. However, most of the researches based on the support are concerned with the frequent event, but ignore the infrequent event even if it is crucial. In this paper, we propose SM-AF method discovering association rules to an abnormal event. In considering the window that an abnormal event is sensed, SM-AF method can discover the association rules to the critical event, even if it is occurred infrequently. Also, SM-AF method can discover the significant rare itemsets associated with abnormal event and periodic event itemsets. Through analysis and experiments, we show that SM-AF method is superior to the previous methods of mining association rules.

• Analytical Science and Technology
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• v.30 no.1
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• pp.1-9
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• 2017

Starch is a mixture of amylose (AMY) and amylopectin (AMP) which are different in physical properties such as molar mass (M), rms radius ($R_g$) and hydrodynamic diameter ($d_H$). The rheological and functional properties of starch are influenced by various factors including the molecular size, molar mass distribution (MD) and the concentration ratio of AMY and AMP. It is also important to analyze proteinaceous material in starch as they affect the flavor and texture of food to which starch is added. In this study, asymmetrical flow field-flow fractionation (AF4) was employed for separation and quantitation of AMY and AMP in starches (Amaranth, potato, taros and quinoa). AF4 was coupled with a multi-angle light scattering (MALS) and a refractive index (RI) detector for determination of the absolute M, MD and molecular structure. It was found that AMP has the M and $R_g$ ranging $3.7{\times}10^7{\sim}6.5{\times}10^8g/mol$ and 84 ~ 250 nm, respectively. Also the existence of branch was confirmed in higher M. In addition, proteinaceous material in starch was analyzed by AF4 coupled with a fluorescence detector (FS) after fluorescence-labeling. AF4-FS with fluorescence-labelling showed a potential for investigation on existence of proteinaceous material and the interaction between proteinaceous material and polysaccharide in starch.

• Korean journal of food and cookery science
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• v.30 no.5
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• pp.540-546
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• 2014

This study was conducted to compare the commercial noodle flours (n=8) of each milling company in Korea. Eight noodle flour samples were classified into two types of flours, all-purpose flour (AF, n=4) and premium noodle flour (PF, n=4) and tested using general component analysis. Texture assessment and sensory test for doughs and noodles were performed. The dough strength was positively correlated with lower ash content, smaller particle size and longer formation time. Sensory evaluation found that weaker cooked noodle strength correlated with higher scores in preference and softness. As a result, it can be suggested that PF is better than AF in noodle making because PF has lower ash content and smaller particle size than AF. As such, flour characteristics that produce noodle flour of uniform quality can be obtained by combining flours with the above processing characteristics to fit the qualities desired.