Journal of Science and Technique
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ADAPTIVE REVERSIBLE DATA HIDING METHOD USING BITMAP CLASSIFICATION STRATEGY FOR AMBTC-COMPRESSED IMAGES
Get PDFReversible data hiding (RDH) has attracted significant attention from researchers. Absolute Moment Block Truncation Coding (AMBTC) compressed image is a popular cover medium in RDH schemes due to its simplicity and high compression ratio. Nevertheless, most AMBTC-based RDH schemes produce stego images that cannot be decoded by standard AMBTC decoders because they use reconstructed pixels to embed data. Although some AMBTC-based RDH schemes generate stego images compatible with AMBTC decoders, their embedding capacity (EC) is limited. To address this issue, in this paper, a high-capacity AMBTC-based RDH scheme compatible with standard decoders is proposed. In this scheme, an effective bitmap classification technique is developed and employed to ensure reversibility and enhance the embedding payload. Furthermore, the proposed scheme provides the ability to adaptively balance the trade-off between hiding the payload and the perceptual quality of stego images by utilizing two predefined thresholds. Experimental results demonstrate that the proposed scheme outperforms related approaches in both embedding payload and visual quality
EXPERIMENTAL RESEARCH ON THE PROPAGATION PARAMETERS OF EXPLOSIVE STRESS WAVE IN CORAL CONCRETE
Get PDFThis study investigates the propagation of stress waves in coral concrete material under explosive conditions. The experimental system was designed to analyze the stress wave characteristics in coral concrete, focusing on the velocity and attenuation of the stress waves as they pass through the material. The study used explosive charges placed at specific depths within boreholes to generate the stress waves, with pressure sensors deployed to record the intensity of the waves at different distances from the center of the explosion. The results obtained are the stress wave intensity over time at different distances from the center of the explosion. Using regression analysis, the propagation velocity of the stress waves was determined, and the attenuation coefficient was calculated based on distance. It was found that the blast-induced stress wave attenuation coefficient in coral concrete with a compressive strength class equivalent to B22.5 is 1.272, while the propagation velocity of the blast-induced stress wave ranges between 3658 m/s and 3817 m/s, with a minimal measurement error of 1.18%. These findings provide valuable insights into the dynamic behavior of coral concrete, contributing to the establishment of formulas for calculating stress wave intensity and blast loading in coral concrete
SYNTHESIS OF 2,4,6,8,10,12-HEXABENZYL-2,4,6,12-HEXAAZATETRACYCLO DODECANE USING MELAMINIUM TRI(HYDROGENSULFATE) AS A SOLID ACID CATALYST
Get PDFIn this article, we successfully synthesized 2,4,6,8,10,12-hexabenzyl-2,4,6,12-hexaazatetracyclo dodecane (HBIW) through a condensation reaction using melaminium tri(hydrogensulfate) as a solid acid catalyst. The structural characteristics of the product were determined using modern analytical methods: IR, DSC, NMR, and HPLC. Factors influencing the yield of the HBIW synthesis reaction were examined, including catalysts and catalyst amount. The results show that using melaminium tri(hydrogensulfate) as a solid catalyst at 10% mol of glyoxal, yields an optimal yield of 89.86%
HIGHLY SELECTIVE NO2 GAS SENSOR OPERATING AT ROOM TEMPERATURE WITH PPB-LEVEL DETECTION SENSITIVITY BASED ON ZnO NANOPARTICLES
Get PDFIn this work, we reported a high-selectivity nitrogen dioxide (NO2) gas sensor that operates directly at room temperature without catalyst or illumination. The NO2 gas sensor was based on ZnO nanoparticles, which were synthesized using a simple solution method, ensuring scalability in mass production. Crucially, the sensor exhibited high sensitivity and selectivity towards NO2, achieving parts-per-billion (ppb) level detection limits. At 23°C, the sensor showed a sensitivity of 4.2 % with the response time and recovery time are 120 s and 185 s, respectively, under 5 ppb NO2, while the interaction with other gases such as H2S, NH3, SO2, CH4, C3H8, and CO2 was negligible. This room-temperature, easily fabricated sensor offered a promising solution for cost-effective, real-time NO2 monitoring in various applications, particularly those requiring high sensitivity at low NO2 concentrations
DEVELOPMENT OF A POWER CONTROL ALGORITHM BASED ON THROUGHPUT WINDOW FOR WIRELESS BODY AREA NETWORKS
Get PDFSensors in Wireless Body Area Networks (WBANs) require low power consumption to ensure continuous long-term operation while maintaining accurate and stable data transmission. This article proposes a novel power control algorithm that significantly improves energy efficiency for WBAN sensors compared to existing schemes. The proposed “Throughput Window-based Power Control” (TWC) algorithm ensures that the sensor’s throughput remains within a predefined range, aligning with system requirements. Simulation results demonstrate that TWC not only significantly reduces energy consumption but also maintains stable communication performance with high reliability under the unique transmission conditions of WBANs. In particular, TWC achieves the highest average energy efficiency, which is 1.5 times higher than the Max-Min Power Control (MMC) algorithm and 7.5 times higher than the No Power Control (NPC) scenario. Moreover, TWC yields the lowest average power consumption, reaching 0.75 times that of MMC and only 0.3 times that of NPC. Compared to MMC and NPC, TWC offers superior energy-saving capability while ensuring quality of service. These findings support the development of energy-autonomous WBAN models that meet the requirements of advanced health monitoring applications
INTRUSION DETECTION USING NETWORK FLOW FEATURE FOR SOFTWARE-DEFINED NETWORKS
Get PDFIn recent years, Software-Defined Networking (SDN) is a new network architecture that has been gaining popularity. This promises to simplify network control and management with centralized control of the network, but it also increases the risk of a single point of failure (SPOF) in the network. To mitigate SPOF, more cyber security research is needed on SDN networks. On the other hand, intrusion detection systems (IDSs) play a crucial role in SDN security by dealing with external threats. Machine learning-based IDSs are well-suited for SDN because they can be trained on a centralized controller. However, there is limited research on SDN intrusion detection systems. Existing literature often treats SDN intrusion detection as similar to intrusion detection in traditional computer systems. This approach can be problematic because SDN networks have different characteristics than traditional computer systems. In this paper, we propose a new method for SDN intrusion detection using machine learning. Our method addresses the problem of data imbalance, which is a common problem with machine learning datasets. We also evaluate our method on the most recent public SDN intrusion detection dataset. Our results show that our method can achieve high accuracy and low false alarm rates. Finally, we evaluate the performance of our method in two different SDN scenarios: with and without load balancing. Our results show that our method can achieve high performance in both scenarios
ENHANCE STEREO VISUAL ODOMETRY PERFORMANCE BY REMOVING UNSTABLE FEATURES
Get PDFVisual odometry includes two important stages: 1) feature extraction and 2) pose estimation. The performance of visual odometry is dependent on the quality of features including the number of features, the percentage of the correct matching, and the location of detected features. Usually, RANSAC method has been used in pose estimation to remove outlier and select a good set of features that provide higher accuracy. However, in the case the higher wrong matches, the RANSAC seems to be failing. This article proposes the removing unstable feature method by deep learning-based object detection. The proposed method evaluated on the KITTI dataset shows a higher accuracy 6 - 8% compared to the conventional method
INVARIANT ZERO-WATERMARKING ALGORITHM IN DWT-DCT DOMAIN USING ROBUST FEATURES MATCHING
Get PDFIn order to protect the copyright of the digital contents, the robust watermarking techniques are employed based on frequency domains or combined frequency domains. Another techniques, called zero-watermarking which does not modify the original image to embed the watermark but create a watermark from its robust features, is a useful technique for resolving the tension between robustness and invisibility. In this paper, we propose a new zero-watermarking algorithm based on discrete wavelet transform and discrete cosine transform domain with significant feature points matching for improving the robustness. In our proposed method, the original image is firstly separated into three components (Y, Cr, Cb), then its Y-component is performed with discrete wavelet transform, afterwards its LL3 is transformed with discrete cosine transform. To generate the master share of the original image, the DCT-based image is binarized. After performing the Arnold transformation on the watermark, the owner share is generated by taking the XOR operation on the scrambled watermark and master share. The robustness of the our proposed algorithm for imaging processes is analyzed, and the results show that the proposed algorithm is robust to common signal processing such as noise, filtering, JPEG compression, geometric attacks such as rotation, scaling, translation and so on
LOAD-BEARING CAPACITY OF STEEL PIPE PILES IN CORAL GRAVELLY SAND CONSIDERING THE EFFECT OF HELICAL PLATE DISTANCE
Get PDFConstruction projects on geological grounds, particularly coral reefs, hold significant importance for national security, defense, and marine economic development. However, the application of new technologies and enhanced pile foundation structures in these projects has been limited. This study focuses on researching and evaluating the correlation between the load capacity of traditional steel pipe piles, which are supplemented with two helical plates, and the variations in the distance of these helical plates along the depth of the pile in coral gravelly-sand using Mohr-Coulomb model by finite element method. The results of this study conclude that the load-bearing capacity of piles with two helical plates is 2.1 to 3.3 times higher than that of traditional plain round piles. In addition, a calculation function for the load-bearing capacity of the improved steel single-pipe pile in relation to the appropriate distance for the helical plates is proposed. This function is essential for projects built under the geological conditions of coral and the typical hydrological properties found in the offshore seas and islands of Vietnam
NGHIÊN CỨU TỔNG HỢP LUẬT ĐIỀU KHIỂN TRƯỢT CHO THIẾT BỊ BAY VỚI HỆ THỐNG DẪN VÀ ĐIỀU KHIỂN TÍCH HỢP
Get PDFThiết bị bay (TBB) có khả năng tấn công và tiêu diệt các mục tiêu đường không đang được nhiều nước trên thế giới sản xuất và đưa vào sử dụng. Bài báo đề xuất tổng hợp hệ thống dẫn và điều khiển tích hợp mới cho TBB dựa trên cơ sở điều khiển trượt (SMGC) nhằm nâng cao chất lượng vòng điều khiển và ứng dụng cho các loại TBB hiện đại với khả năng cơ động cao. Bài báo nghiên cứu so sánh hệ SMGC với hệ thống thông thường sử dụng hai vòng dẫn và điều khiển độc lập SMG-SMC, từ đó đánh giá ưu, nhược điểm cũng như chất lượng và độ chính xác của hệ thống tích hợp mới được tổng hợp. Kết quả bài báo cho thấy hệ thống tích hợp sử dụng điều khiển trượt có chất lượng tốt hơn và có ưu điểm đáng kể trong trường hợp tiếp cận mục tiêu có tính cơ động cao, độ trượt thấp hơn và góc lệch cánh lái ít bị dao động khi so sánh với hệ thống dẫn và điều khiển thông thường