This paper proposes a dual-frequency polarization-multiplexed metasurface for Orbital angular momentum (OAM) divergence control using phased-array principles. Compared to FSS-Ioaded designs, the unit achieves ultrathin profile, full-phase coverage, and angle insensitivity. By implementing phased-array-based divergence tuning, we demonstrate four-channel high-purity vortex beams with equal divergence angles across modes. Fabricated prototypes validate the OAM control capability, showing good agreement between simulated and measured results. The design shows strong potential for vortex-beam communications and radar detection.
{"title":"A Metasurface Implementing Phased-Array-based Vortex Beam Divergence Control for Generating Four-Channel Equal Divergence Angle Vortex Beams","authors":"Zhiwei Wang;Yongzhong Zhu;Junwei Xu;Hanchu Zhou;Wenxuan Xie","doi":"10.23919/comex.2025XBL0114","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0114","url":null,"abstract":"This paper proposes a dual-frequency polarization-multiplexed metasurface for Orbital angular momentum (OAM) divergence control using phased-array principles. Compared to FSS-Ioaded designs, the unit achieves ultrathin profile, full-phase coverage, and angle insensitivity. By implementing phased-array-based divergence tuning, we demonstrate four-channel high-purity vortex beams with equal divergence angles across modes. Fabricated prototypes validate the OAM control capability, showing good agreement between simulated and measured results. The design shows strong potential for vortex-beam communications and radar detection.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 12","pages":"464-468"},"PeriodicalIF":0.3,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11202643","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To reduce the risks of natural disasters, proactive use of environmental data is important. However, securing electricity in rural areas is often challenging. Thus, IoT gateways powered by power-over-fiber (PoF) are required. In this work, we develop an intermittent IoT gateway by implementing a task-aware module operation algorithm suitable for intermittent IoT sensing with power-limited PoF. The algorithm selectively powers the necessary modules and minimizes their operating time during the active state. As a result, power consumption in the active state is reduced by 56% compared with previous work, in which almost all modules were activated. Furthermore, the algorithm suppresses the temperature increase of the transmitter, one of the most power-hungry modules, by ~ 11K.
{"title":"Task-Aware Module Operation in IoT Gateways Enabling Power and Temperature Reduction for Power-over-Fiber Application","authors":"Suguru Yamaoka;Masaki Mizuno;Youichi Fukada;Ryo Miyatake;Yoshihito Sakai;Masayoshi Sekiguchi;Tatsuya Shimada","doi":"10.23919/comex.2025XBL0110","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0110","url":null,"abstract":"To reduce the risks of natural disasters, proactive use of environmental data is important. However, securing electricity in rural areas is often challenging. Thus, IoT gateways powered by power-over-fiber (PoF) are required. In this work, we develop an intermittent IoT gateway by implementing a task-aware module operation algorithm suitable for intermittent IoT sensing with power-limited PoF. The algorithm selectively powers the necessary modules and minimizes their operating time during the active state. As a result, power consumption in the active state is reduced by 56% compared with previous work, in which almost all modules were activated. Furthermore, the algorithm suppresses the temperature increase of the transmitter, one of the most power-hungry modules, by ~ 11K.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 12","pages":"469-472"},"PeriodicalIF":0.3,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11202645","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.23919/comex.2025XBL0091
Thanh Trung Nguyen;Minh Hai Vu;Phi Le Nguyen;Kien Nguyen
Quick UDP Internet Connections (QUIC), an advanced IETF transport-layer protocol, offers several significant advantages over traditional TCP, including reduced latency, enhanced multiplexing capabilities, and strong security through built-in encryption and optimized handshake processes. Because of these benefits, even before its standardization in 2021, QUIC was widely deployed by major Internet companies such as Google and Facebook. Additionally, previous research has observed an increase in global adoption of QUIC. Motivated by this trend, we investigate QUIC deployment in Vietnam, particularly in the context of the country's rapid development, especially in the ICT sector. Specifically, we scan and analyze QUIC adoption using a Vietnamese IPv4 dataset. The scanning results indicate that QUIC adoption in Vietnam is in the early stages, with a low deployment rate of approximately 0.05% of all Vietnamese IPv4 addresses. Furthermore, we analyze active migration support, TLS encryption preferences, and visualize a map of QUIC adoption to track its ongoing deployment patterns. In addition, we conduct active measurements showing that QUIC achieves lower time to first byte (TTFB) and higher throughput than TCP in Wi-Fi networks, while offering competitive performance in mobile networks.
{"title":"Analysis and Visualization of QUIC Protocol Deployment in Vietnam","authors":"Thanh Trung Nguyen;Minh Hai Vu;Phi Le Nguyen;Kien Nguyen","doi":"10.23919/comex.2025XBL0091","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0091","url":null,"abstract":"Quick UDP Internet Connections (QUIC), an advanced IETF transport-layer protocol, offers several significant advantages over traditional TCP, including reduced latency, enhanced multiplexing capabilities, and strong security through built-in encryption and optimized handshake processes. Because of these benefits, even before its standardization in 2021, QUIC was widely deployed by major Internet companies such as Google and Facebook. Additionally, previous research has observed an increase in global adoption of QUIC. Motivated by this trend, we investigate QUIC deployment in Vietnam, particularly in the context of the country's rapid development, especially in the ICT sector. Specifically, we scan and analyze QUIC adoption using a Vietnamese IPv4 dataset. The scanning results indicate that QUIC adoption in Vietnam is in the early stages, with a low deployment rate of approximately 0.05% of all Vietnamese IPv4 addresses. Furthermore, we analyze active migration support, TLS encryption preferences, and visualize a map of QUIC adoption to track its ongoing deployment patterns. In addition, we conduct active measurements showing that QUIC achieves lower time to first byte (TTFB) and higher throughput than TCP in Wi-Fi networks, while offering competitive performance in mobile networks.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 11","pages":"415-418"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157906","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A propeller LED transmitter (P-Tx) further boosts image sensor communication (IS C) throughput by mounting LEDs on a rotating arm and encoding data via their On/Off state. Reducing the angular interval per bit increases data rate but also raises the risk of overlapping “light trails” and ensuing interference. To date, no analytical model has linked the control angle to inter-trail interference in P-Tx-based ISC. This paper proposes a fundamental model of light trail generation and blinking control conditions to prevent interference between adjacent light trails. In the proposed model, the luminous energy distribution on the image plane is calculated based on the LED rotation trajectory. We also provide preliminary experimental results to validate the proposed model.
{"title":"Theoretical Modeling and Interference Prevention of Light Trails for LED-Propeller Based Image Sensor Communication","authors":"Shin Asaoka;Shan Lu;Takaya Yamazato;Zhengqiang Tang","doi":"10.23919/comex.2025COL0011","DOIUrl":"https://doi.org/10.23919/comex.2025COL0011","url":null,"abstract":"A propeller LED transmitter (P-Tx) further boosts image sensor communication (IS C) throughput by mounting LEDs on a rotating arm and encoding data via their On/Off state. Reducing the angular interval per bit increases data rate but also raises the risk of overlapping “light trails” and ensuing interference. To date, no analytical model has linked the control angle to inter-trail interference in P-Tx-based ISC. This paper proposes a fundamental model of light trail generation and blinking control conditions to prevent interference between adjacent light trails. In the proposed model, the luminous energy distribution on the image plane is calculated based on the LED rotation trajectory. We also provide preliminary experimental results to validate the proposed model.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 12","pages":"436-440"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157908","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unmanned aerial vehicles (UAVs) are attracting attention for applications such as delivery services. In dense UAV traffic, efficient route management is critical for safe navigation. We previously proposed a distributed UAV management system based on a virtual circuit concept, where UAV routes are established over a multi-hop wireless network formed by devices installed in individual houses. To avoid collisions, the system reserves both UAV routes and their crossing links. However, as the number of UAVs increases, link availability decreases, leading to frequent route construction failures. This letter proposes an improved method that reserves only the links currently used by UAVs in flight and their crossing links. Simulation results confirm the effectiveness of the proposed method.
{"title":"OLSR-Based UAV Route Construction Method with Reservation of in-Flight and Crossing Links","authors":"Akito Maeda;Kiyoshi Ueda;Takumi Miyoshi;Taku Yamazaki;Ryo Yamamoto","doi":"10.23919/comex.2025XBL0095","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0095","url":null,"abstract":"Unmanned aerial vehicles (UAVs) are attracting attention for applications such as delivery services. In dense UAV traffic, efficient route management is critical for safe navigation. We previously proposed a distributed UAV management system based on a virtual circuit concept, where UAV routes are established over a multi-hop wireless network formed by devices installed in individual houses. To avoid collisions, the system reserves both UAV routes and their crossing links. However, as the number of UAVs increases, link availability decreases, leading to frequent route construction failures. This letter proposes an improved method that reserves only the links currently used by UAVs in flight and their crossing links. Simulation results confirm the effectiveness of the proposed method.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 11","pages":"390-392"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157911","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.23919/comex.2025XBL0102
Shugang Liu;Weihua Lei;Qiangguo Yu;Kun Xu
In this study, a lightweight semantic communication scheme is proposed to address the issues of large storage overhead and limited adaptability caused by the dynamic signal-to-noise ratio (SNR) variations in wireless channels, which necessitate storing multiple SNR-specific models in conventional semantic communication schemes. The scheme integrates ghost convolution (GC) and a global attention mechanism (GAM) module. Experimental results demonstrate: a 300% reduction in parameters, FLOPs, and model storage while maintaining comparable performance to conventional convolutional models; under the 3dB Gaussian channel, the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index Measure(SSIM) reach 27dB and 0.9 respectively; under the Rayleigh channel at identical SNR, PSNR and SSIM achieve 25dB and 0.8. The approach significantly reduces deep learning model complexity while preserving image reconstruction quality, effectively solving the multi-SNR adaptation versus storage trade-off, and establishing a new idea for the image semantic communication scheme.
{"title":"A Lightweight Image Transmission Scheme for Deep Learning-Based Semantic Communication","authors":"Shugang Liu;Weihua Lei;Qiangguo Yu;Kun Xu","doi":"10.23919/comex.2025XBL0102","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0102","url":null,"abstract":"In this study, a lightweight semantic communication scheme is proposed to address the issues of large storage overhead and limited adaptability caused by the dynamic signal-to-noise ratio (SNR) variations in wireless channels, which necessitate storing multiple SNR-specific models in conventional semantic communication schemes. The scheme integrates ghost convolution (GC) and a global attention mechanism (GAM) module. Experimental results demonstrate: a 300% reduction in parameters, FLOPs, and model storage while maintaining comparable performance to conventional convolutional models; under the 3dB Gaussian channel, the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index Measure(SSIM) reach 27dB and 0.9 respectively; under the Rayleigh channel at identical SNR, PSNR and SSIM achieve 25dB and 0.8. The approach significantly reduces deep learning model complexity while preserving image reconstruction quality, effectively solving the multi-SNR adaptation versus storage trade-off, and establishing a new idea for the image semantic communication scheme.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 11","pages":"402-405"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157907","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High transmission quality is essential for wireless communication. To meet this demand, we propose an approach to enhance the modulation method using Voronoi constellations (VCs) based on an $N$-dimensional lattice partition. Compared to traditional methods such as $M$-ary phase-shift keying ($M$-PSK) and $M$-ary quadrature amplitude modulation ($M$-QAM) on a two-dimensional plane, $N$-dimensional VCs offer a larger Euclidean distance between signal points, resulting in superior error rate performance in additive white Gaussian noise (AWGN) channels. To further improve performance in fading channels, we introduce new VCs that achieve diversity gain by rotating the constellation in $N$-dimensional space while preserving AWGN channel characteristics. Numerical results demonstrate that VCs achieve a 25 dB gain for QPSK and a 17 dB gain for 16QAM at a block error rate of 10−4 in a symbol-independent and identically distributed (i.i.d.) Rayleigh fading channel. Additionally, as the achieved diversity gain is influenced by fading variations, the effective range of these gains was clarified in accordance with the 5G New Radio (NR) radio interface.
{"title":"Performance Improvement of Voronoi Constellations by Multi-Dimensional Rotation for Fading Channels","authors":"Ryo Tozawa;Eiji Okamoto;Naoto Horiike;Tetsuya Yamamoto","doi":"10.23919/comex.2025XBL0106","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0106","url":null,"abstract":"High transmission quality is essential for wireless communication. To meet this demand, we propose an approach to enhance the modulation method using Voronoi constellations (VCs) based on an <tex>$N$</tex>-dimensional lattice partition. Compared to traditional methods such as <tex>$M$</tex>-ary phase-shift keying (<tex>$M$</tex>-PSK) and <tex>$M$</tex>-ary quadrature amplitude modulation (<tex>$M$</tex>-QAM) on a two-dimensional plane, <tex>$N$</tex>-dimensional VCs offer a larger Euclidean distance between signal points, resulting in superior error rate performance in additive white Gaussian noise (AWGN) channels. To further improve performance in fading channels, we introduce new VCs that achieve diversity gain by rotating the constellation in <tex>$N$</tex>-dimensional space while preserving AWGN channel characteristics. Numerical results demonstrate that VCs achieve a 25 dB gain for QPSK and a 17 dB gain for 16QAM at a block error rate of 10<sup>−4</sup> in a symbol-independent and identically distributed (i.i.d.) Rayleigh fading channel. Additionally, as the achieved diversity gain is influenced by fading variations, the effective range of these gains was clarified in accordance with the 5G New Radio (NR) radio interface.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 11","pages":"393-397"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157912","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.23919/comex.2025XBL0099
Takumi Senaha;Taito Baba;Takuya Asaka
Maximizing the bottleneck bandwidth of communication paths is a critical challenge for bandwidth-intensive applications. This study proposes a distributed-routing method based on ant colony optimization that dynamically adjusts pheromones according to locally learned path quality. The method's key feature is its ability to adapt to changing network conditions using local statistics, making it suitable for dynamic environments such as information-centric networking, where content sources change frequently. Simulation results indicate high convergence and effective selection of optimal paths with the proposed method.
{"title":"A Distributed Approach for Maximum-Bandwidth-Path Discovery Using Ant Colony Optimization","authors":"Takumi Senaha;Taito Baba;Takuya Asaka","doi":"10.23919/comex.2025XBL0099","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0099","url":null,"abstract":"Maximizing the bottleneck bandwidth of communication paths is a critical challenge for bandwidth-intensive applications. This study proposes a distributed-routing method based on ant colony optimization that dynamically adjusts pheromones according to locally learned path quality. The method's key feature is its ability to adapt to changing network conditions using local statistics, making it suitable for dynamic environments such as information-centric networking, where content sources change frequently. Simulation results indicate high convergence and effective selection of optimal paths with the proposed method.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 11","pages":"398-401"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157913","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.23919/comex.2025XBL0107
Lin Wang;Zhongqiang Luo;Lin Gao
To address the issues of contrast degradation and colour distortion in video images captured by the device in haze and other environments, the contrast-limited adaptive histogram equalization (CLAHE) algorithm is improved, and a joint bilateral filtering algorithm for image enhancement is proposed. The CLAHE algorithm and bilateral filtering algorithm are applied to the bright channel Y in the YUV colour space. The parallel pipeline architecture of the ZYNQ platform is utilized to combine RAM and FPGA to realize hardware and software synergy. The experimental results demonstrate that the algorithm has improved the peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), Underwater Image Quality Measure (UIQM), and Average Gradient (AG) and information entropy (IE) of the image. Consuming only 2.278 W on the FPGA, this hardware circuit falls into the low-power category.
{"title":"An Improved Video Dehazing Algorithm Based on ZYNQ Architecture","authors":"Lin Wang;Zhongqiang Luo;Lin Gao","doi":"10.23919/comex.2025XBL0107","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0107","url":null,"abstract":"To address the issues of contrast degradation and colour distortion in video images captured by the device in haze and other environments, the contrast-limited adaptive histogram equalization (CLAHE) algorithm is improved, and a joint bilateral filtering algorithm for image enhancement is proposed. The CLAHE algorithm and bilateral filtering algorithm are applied to the bright channel Y in the YUV colour space. The parallel pipeline architecture of the ZYNQ platform is utilized to combine RAM and FPGA to realize hardware and software synergy. The experimental results demonstrate that the algorithm has improved the peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), Underwater Image Quality Measure (UIQM), and Average Gradient (AG) and information entropy (IE) of the image. Consuming only 2.278 W on the FPGA, this hardware circuit falls into the low-power category.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"15 3","pages":"29-32"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157902","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147352572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we propose a text-based CAPTCHA that utilizes human visual completion to prevent automated programs from getting through, without affecting human cognition. This CAPTCHA requires users to enter the reading of the kanji strings, whose centers are hidden behind a black bar. This method makes it challenging for machines to recognize the characters, while still allowing humans to identify the original text through their visual completion ability. We evaluate both the usability and security of the proposed CAPTCHA. To assess usability, we observed how humans respond to the CAPTCHA challenge. For the security evaluation, we tested the machine's ability to read the kanji using a Convolutional Neural Network (CNN). The results showed that the proposed CAPTCHA achieves a success rate comparable to traditional CAPTCHAs, with a slightly shorter response time than a similar type of CAPTCHA. Furthermore, security experiments have shown that it exhibits a certain degree of resistance against simple convolutional neural networks.
{"title":"Evaluating the Usability and Security of the Text-Based CAPTCHA that Asks to Recognize Hidden Text with the Help of Human Visual Completion Function","authors":"Shotaro Usuzaki;Nobuya Takahashi;Taiki Kamada;Kentaro Aburada;Hisaaki Yamaba;Mirang Park;Naonobu Okazaki","doi":"10.23919/comex.2025COL0018","DOIUrl":"https://doi.org/10.23919/comex.2025COL0018","url":null,"abstract":"In this study, we propose a text-based CAPTCHA that utilizes human visual completion to prevent automated programs from getting through, without affecting human cognition. This CAPTCHA requires users to enter the reading of the kanji strings, whose centers are hidden behind a black bar. This method makes it challenging for machines to recognize the characters, while still allowing humans to identify the original text through their visual completion ability. We evaluate both the usability and security of the proposed CAPTCHA. To assess usability, we observed how humans respond to the CAPTCHA challenge. For the security evaluation, we tested the machine's ability to read the kanji using a Convolutional Neural Network (CNN). The results showed that the proposed CAPTCHA achieves a success rate comparable to traditional CAPTCHAs, with a slightly shorter response time than a similar type of CAPTCHA. Furthermore, security experiments have shown that it exhibits a certain degree of resistance against simple convolutional neural networks.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 12","pages":"441-444"},"PeriodicalIF":0.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11157905","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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