ETRI JournalPub Date : 2024-04-20DOI: 10.4218/etrij.2023-0401
Yan Shi, Dongqing Zhao, Yue Wu
{"title":"Hybrid intelligent reflective surfaces and relay assisted secure transmission scheme with power allocation","authors":"Yan Shi, Dongqing Zhao, Yue Wu","doi":"10.4218/etrij.2023-0401","DOIUrl":"10.4218/etrij.2023-0401","url":null,"abstract":"<p>To improve the security and reliability of communication transmissions, this study proposes a novel hybrid secure scheme that combines a decode-and-forward (DF) relay and an intelligent reflecting surface (IRS) for downlinking multiple-input single-output systems. The proposal maximizes the minimum achievable secrecy rate by utilizing alternating optimization algorithms to derive the closed-form solution of the beamforming vector, obtain the optimal power allocation factor with the successive convex approximation method, and obtain the optimal phase-shift matrix with the semi-definite relaxation method. The simulation results demonstrate that our approach outperforms state-of-the-art solutions using only the IRS or DF relay. Moreover, performance improves at a high signal-to-noise when increasing the number of IRSs. Notably, a proper power allocation is important to achieve optimal performance.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"47 1","pages":"158-166"},"PeriodicalIF":1.3,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0401","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140679246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-04-16DOI: 10.4218/etrij.2023-0285
Joonsun Auh, Changsik Cho, Seon-tae Kim
{"title":"Improved contrastive learning model via identification of false-negatives in self-supervised learning","authors":"Joonsun Auh, Changsik Cho, Seon-tae Kim","doi":"10.4218/etrij.2023-0285","DOIUrl":"10.4218/etrij.2023-0285","url":null,"abstract":"<p>Self-supervised learning is a method that learns the data representation through unlabeled data. It is efficient because it learns from large-scale unlabeled data and through continuous research, performance comparable to supervised learning has been reached. Contrastive learning, a type of self-supervised learning algorithm, utilizes data similarity to perform instance-level learning within an embedding space. However, it suffers from the problem of false-negatives, which are the misclassification of data class during training the data representation. They result in loss of information and deteriorate the performance of the model. This study employed cosine similarity and temperature simultaneously to identify false-negatives and mitigate their impact to improve the performance of the contrastive learning model. The proposed method exhibited a performance improvement of up to 2.7% compared with the existing algorithm on the CIFAR-100 dataset. Improved performance on other datasets such as CIFAR-10 and ImageNet was also observed.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"46 6","pages":"1020-1029"},"PeriodicalIF":1.3,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0285","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140697047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-04-12DOI: 10.4218/etrij.2023-0249
Hyemi Kim, Junghyun Kim, Jihyun Park, Seongwoo Kim, Chanjin Park, Wonyoung Yoo
{"title":"Background music monitoring framework and dataset for TV broadcast audio","authors":"Hyemi Kim, Junghyun Kim, Jihyun Park, Seongwoo Kim, Chanjin Park, Wonyoung Yoo","doi":"10.4218/etrij.2023-0249","DOIUrl":"10.4218/etrij.2023-0249","url":null,"abstract":"<p>Music identification is widely regarded as a solved problem for music searching in quiet environments, but its performance tends to degrade in TV broadcast audio owing to the presence of dialogue or sound effects. In addition, constructing an accurate dataset for measuring the performance of background music monitoring in TV broadcast audio is challenging. We propose a framework for monitoring background music by automatic identification and introduce a background music cue sheet. The framework comprises three main components: music identification, music–speech separation, and music detection. In addition, we introduce the Cue-K-Drama dataset, which includes reference songs, audio tracks from 60 episodes of five Korean TV drama series, and corresponding cue sheets that provide the start and end timestamps of background music. Experimental results on the constructed and existing datasets demonstrate that the proposed framework, which incorporates music identification with music–speech separation and music detection, effectively enhances TV broadcast audio monitoring.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"46 4","pages":"697-707"},"PeriodicalIF":1.3,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0249","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140596641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-04-12DOI: 10.4218/etrij.2023-0375
YoungMin Ko, SunWoo Ko, YoungSoo Kim
{"title":"Generative autoencoder to prevent overregularization of variational autoencoder","authors":"YoungMin Ko, SunWoo Ko, YoungSoo Kim","doi":"10.4218/etrij.2023-0375","DOIUrl":"10.4218/etrij.2023-0375","url":null,"abstract":"<p>In machine learning, data scarcity is a common problem, and generative models have the potential to solve it. The variational autoencoder is a generative model that performs variational inference to estimate a low-dimensional posterior distribution given high-dimensional data. Specifically, it optimizes the evidence lower bound from regularization and reconstruction terms, but the two terms are imbalanced in general. If the reconstruction error is not sufficiently small to belong to the population, the generative model performance cannot be guaranteed. We propose a generative autoencoder (GAE) that uses an autoencoder to first minimize the reconstruction error and then estimate the distribution using latent vectors mapped onto a lower dimension through the encoder. We compare the Fréchet inception distances scores of the proposed GAE and nine other variational autoencoders on the MNIST, Fashion MNIST, CIFAR10, and SVHN datasets. The proposed GAE consistently outperforms the other methods on the MNIST (44.30), Fashion MNIST (196.34), and SVHN (77.53) datasets.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"47 1","pages":"80-89"},"PeriodicalIF":1.3,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140596643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-04-08DOI: 10.4218/etrij.2023-0448
Yuchan Gao, Jing Su, Jia Li, Shenglong Wang, Chao Li
{"title":"A neural network framework based on ConvNeXt for side-channel hardware Trojan detection","authors":"Yuchan Gao, Jing Su, Jia Li, Shenglong Wang, Chao Li","doi":"10.4218/etrij.2023-0448","DOIUrl":"10.4218/etrij.2023-0448","url":null,"abstract":"<p>Researchers in the field of hardware security have been dedicated to the study of hardware Trojan detection. Among the various approaches, side-channel detection methods are widely used because of their high detection accuracy and fewer constraints. However, most side-channel detection methods cannot make full use of side-channel information. In this paper, we propose a framework that utilizes the continuous wavelet transform to convert time-series information and employs an improved ConvNeXt network to detect hardware Trojans. This detection framework first converts one-dimensional time-series information into a two-dimensional time–frequency map using the continuous wavelet transform to leverage frequency information in electromagnetic side-channel signals. Then, the two-dimensional time–frequency map is fed into the improved ConvNeXt network, which increases the weight of the informative parts in the two-dimensional time–frequency map and enhances detection efficiency. The results indicate that the method proposed in this paper significantly improves the accuracy of hardware Trojan detection.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"47 2","pages":"338-349"},"PeriodicalIF":1.3,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0448","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140596752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-04-05DOI: 10.4218/etrij.2023-0250
Sung-Jae Chang, Hyeon-Seok Jeong, Hyun-Wook Jung, Su-Min Choi, Il-Gyu Choi, Youn-Sub Noh, Seong-Il Kim, Sang-Heung Lee, Ho-Kyun Ahn, Dong Min Kang, Dae-Hyun Kim, Jong-Won Lim
{"title":"Effects of parasitic gate capacitance and gate resistance on radiofrequency performance in LG = 0.15 μm GaN high-electron-mobility transistors for X-band applications","authors":"Sung-Jae Chang, Hyeon-Seok Jeong, Hyun-Wook Jung, Su-Min Choi, Il-Gyu Choi, Youn-Sub Noh, Seong-Il Kim, Sang-Heung Lee, Ho-Kyun Ahn, Dong Min Kang, Dae-Hyun Kim, Jong-Won Lim","doi":"10.4218/etrij.2023-0250","DOIUrl":"10.4218/etrij.2023-0250","url":null,"abstract":"<p>The effects of the parasitic gate capacitance and gate resistance (<i>R</i><sub>g</sub>) on the radiofrequency (RF) performance are investigated in <i>L</i><sub>G</sub> = 0.15 μm GaN high-electron-mobility transistors with T-gate head size ranging from 0.83 to 1.08 μm. When the device characteristics are compared, the difference in DC characteristics is negligible. The RF performance in terms of the current-gain cut-off frequency (<i>f</i><sub>T</sub>) and maximum oscillation frequency (<i>f</i><sub>max</sub>) substantially depend on the T-gate head size. For clarifying the T-gate head size dependence, small-signal modeling is conducted to extract the parasitic gate capacitance and <i>R</i><sub>g</sub>. When the T-gate head size is reduced from 1.08 to 0.83 μm, <i>R</i><sub>g</sub> increases by 82%, while <i>f</i><sub>T</sub> and <i>f</i><sub>max</sub> improve by 27% and 26%, respectively, because the parasitic gate–source and gate–drain capacitances reduce by 19% and 43%, respectively. Therefore, minimizing the parasitic gate capacitance is more effective that reducing <i>R</i><sub>g</sub> in our transistor design and fabrication, leading to improved RF performance when reducing the T-gate head size.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"46 6","pages":"1090-1102"},"PeriodicalIF":1.3,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0250","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140596732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-04-02DOI: 10.4218/etrij.2023-0397
Chan Young Jung, Yun Jang
{"title":"Small dataset augmentation with radial basis function approximation for causal discovery using constraint-based method","authors":"Chan Young Jung, Yun Jang","doi":"10.4218/etrij.2023-0397","DOIUrl":"10.4218/etrij.2023-0397","url":null,"abstract":"<p>Causal analysis involves analysis and discovery. We consider causal discovery, which implies learning and discovering causal structures from available data, owing to the significance of interpreting causal relationships in various fields. Research on causal discovery has been primarily focused on constraint- and score-based interpretable methods rather than on methods based on complex deep learning models. However, identifying causal relationships in real-world datasets remains challenging. Numerous studies have been conducted using small datasets with established ground truths. Moreover, constraint-based methods are based on conditional independence tests. However, such tests have a lower statistical power when applied to small datasets. To solve the small sample size problem, we propose a model that generates a continuous function from available samples using radial basis function approximation. We address the problem by extracting data from the generated continuous function and evaluate the proposed method on both real and synthetic datasets generated by structural equation modeling. The proposed method outperforms constraint-based methods using only small datasets.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"47 1","pages":"90-101"},"PeriodicalIF":1.3,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0397","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140596642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-03-22DOI: 10.4218/etrij.2023-0389
Khuong Ho-Van
{"title":"Performance analysis of transmit antenna selection and maximum-ratio combining in overlay networks powered by harvested energy","authors":"Khuong Ho-Van","doi":"10.4218/etrij.2023-0389","DOIUrl":"10.4218/etrij.2023-0389","url":null,"abstract":"<p>We aim to improve both the energy harvesting efficiency and communication reliability of overlay networks powered by harvested energy. To this end, multiple antennas are considered to collect energy efficiently and perform reliable decoding by selecting the transmitting antenna and applying maximum-ratio combining. To further improve communication reliability, nonorthogonal multiple access (NOMA)-relied decoding is applied to the secondary receiver. For performance evaluation, exact formulas for the secondary/primary outage probability are derived in a closed form. The evaluation results show that the proposed method substantially outperforms a baseline without the NOMA-relied decoding in all the system settings. The performance of the proposed method is determined by multiple specifications and optimized by allocating the times for energy harvesting and information processing.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"46 6","pages":"987-997"},"PeriodicalIF":1.3,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0389","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-03-22DOI: 10.4218/etrij.2023-0300
Hayder S. R. Hujijo, Muhammad Ilyas
{"title":"Enhancing spectral efficiency with low complexity filtered-orthogonal frequency division multiplexing in visible light communication system","authors":"Hayder S. R. Hujijo, Muhammad Ilyas","doi":"10.4218/etrij.2023-0300","DOIUrl":"10.4218/etrij.2023-0300","url":null,"abstract":"<p>The filtered-orthogonal frequency division multiplexing (F-OFDM) scheme has gained attention as a promising solution in the field of visible light communication (VLC) systems. One crucial aspect in VLC is the conversion of the complex F-OFDM signal into a real signal that corresponds with direct detection and intensity modulation. Traditionally, achieving a real F-OFDM signal has involved imposing Hermitian symmetry (HS) on the samples of the Inverse Fast Fourier transform (IFFT), which requires 2N-point IFFT and obtains an N-point FFT, thus adding complexity. In this study, a novel approach is presented and implemented, aiming to enhance spectral efficiency and reduce system complexity by generating a real F-OFDM signal without relying on HS. This approach is then compared with HS-free (HSF)-OFDM, direct current biased optical OFDM, and asymmetrically clipped optical OFDM. The suggested method offers a remarkable improvement of ~50% in the required IFFT/FFT volume. Consequently, this method reduces hardware complexity and power usage compared with the traditional F-OFDM method. Moreover, regarding error rates, the proposed method demonstrates better spectral efficiency than HSF-OFDM.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"46 6","pages":"1007-1019"},"PeriodicalIF":1.3,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0300","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ETRI JournalPub Date : 2024-03-22DOI: 10.4218/etrij.2023-0123
Husnu Baris Baydargil, Jangsik Park, Ibrahim Furkan Ince
{"title":"Anomaly-based Alzheimer's disease detection using entropy-based probability Positron Emission Tomography images","authors":"Husnu Baris Baydargil, Jangsik Park, Ibrahim Furkan Ince","doi":"10.4218/etrij.2023-0123","DOIUrl":"10.4218/etrij.2023-0123","url":null,"abstract":"<p>Deep neural networks trained on labeled medical data face major challenges owing to the economic costs of data acquisition through expensive medical imaging devices, expert labor for data annotation, and large datasets to achieve optimal model performance. The heterogeneity of diseases, such as Alzheimer's disease, further complicates deep learning because the test cases may substantially differ from the training data, possibly increasing the rate of false positives. We propose a reconstruction-based self-supervised anomaly detection model to overcome these challenges. It has a dual-subnetwork encoder that enhances feature encoding augmented by skip connections to the decoder for improving the gradient flow. The novel encoder captures local and global features to improve image reconstruction. In addition, we introduce an entropy-based image conversion method. Extensive evaluations show that the proposed model outperforms benchmark models in anomaly detection and classification using an encoder. The supervised and unsupervised models show improved performances when trained with data preprocessed using the proposed image conversion method.</p>","PeriodicalId":11901,"journal":{"name":"ETRI Journal","volume":"46 3","pages":"513-525"},"PeriodicalIF":1.4,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.4218/etrij.2023-0123","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}