95 research outputs found
Experimental investigation of the influence of wire offset and composition on complex profile WEDM of Ti6Al4V using trim-pass strategy
No full textWire electric discharge machining (WEDM) is an important non-traditional manufacturing technique for industries processing hard-to-machine materials. It can produce complex shapes with high dimensional accuracy and surface finish. Ti6Al4V is frequently used in biomedical applications such as surgical implants, dentistry, and orthopedic wires. All these applications require machining complex profiles with high accuracy in terms of dimensions and surface properties. Multi-pass machining is a proven technique for minimizing the damage on the machined surface but increasing the number of passes lowers the productivity. Hence, careful selection of wire offset value for trim cutting is crucial to maintain process efficiency and keep the number of passes minimum. The objective of this study is to investigate the effect of wire offset in multi-pass machining on surface integrity, dimensional accuracy, and cutting speed in complex WEDM of Ti6Al4V and limit the number of trim passes to one. In addition, effect of electrode composition on machining responses is studied for three different types of wires (uncoated brass, Broncocut-W, and Topas Plus X). Experimental results indicate that a single trim cut at an offset value of 0.11mmprovides better surface finish and minimum recast layer. Surface roughness of 1.31 mu m is obtained using brass wire: 16.5% and 18.6% less than for Broncocut-W and Topas plus X, respectively. Similarly, recast layer of 8.183 mu m attained by brass wire is smaller than 8.98 mu m, and 10.041 mu m produced by the other wires. The uncoated brass wire has proved to be the best electrode for surface finish, recast layer thickness, and dimensional accuracy of the machined profile. However, Bronococut-W wire has performed better in terms of cutting speed
Probabilistic and Risk Analysis ofChannel Allocation Schemes,based on Markov Chain Model,used for Next Generation Networks
No full textA Comparative Study of Physical and Chemical Method for Separation of Benzoic Acid from Industrial Waste Stream
No full textUsing image steganography for providing enhanced medical data security
No full textRecently, image steganography is being considered as an alternative method for securing medical data to avoid medical related cybercrimes. This paper proposes a new image steganography approach for securing medical data. Swapped Huffman tree coding is used to apply lossless compression and manifold encryption to the payload before embedding into the cover image. Additionally, only edge regions of the cover image are used to embed the secret data which offers high imperceptibility. The results show that the proposed method ensures confidentiality and secrecy of patient information while maintaining imperceptibility
Channel resource allocation and availability prediction in hybrid access femtocells
No full textIn this paper, three channel assignment models are proposed for channel resource allocation in femtocells. The models proposed are based on the Markov chain process. According to the access mechanisms in femtocells, the Third-Generation Partnership Project (3GPP) has described two kinds of users in the femtocell application; open users and the closed subscriber group (CSG). In hybrid access mechanism for femtocells, both CSG users and open users are usually referred as subscribers and non-subscribers respectively. So, in this work, for all the proposed models, the CSG and open users are categorized into two groups; the subscriber group (SG) and the non-subscriber group (NSG) respectively. The proposed models provide priority based channel resource allocation strategies between the SG and NSG. Furthermore, the focus of this research is to provide variable channel resource sharing among the SG and NSG to keep the wastage of channel resources minimum for better quality of service (QoS). The analysis is conducted in terms of channel resource blocking management for all the models and to validate the analysis, simulations are performed at the end of this paper. Further, channel resource blocking prediction, based on the blocking probability results for SG and NSG users, is also provided at the end. The prediction is done through risk analysis using the @ Risk tool. The simulations are provided in two parts; 1) the probability curves for SG and NSG against the total number of channels and 2) the risk analysis results for blocked channels prediction using the @ Risk tool
Quality assessment for wireless capsule endoscopy videos compressed via HEVC: From diagnostic quality to visual perception
No full textMaintaining the quality of medical images and videos is an essential part of the e-services provided by the healthcare sector. The convergence of modern communication systems and the healthcare industry necessitates the provision of better quality of service and experience by the service provider. Recent inclusion and standardization of the high efficiency video coder (HEVC) has made it possible for medical data to be compressed and transmitted over wireless networks with minimal compromise of the quality. Quality evaluation and assessment of these medical videos transmitted over wireless networks is another important research area that requires further exploration and attention. In this paper, we have conducted an in-depth study of video quality assessment for compressed wireless capsule endoscopy (WCE) videos. Our study includes the performance evaluation of several state-of-the-art objective video quality metrics in terms of determining the quality of compressed WCE videos. Subjective video quality experiments were conducted with the assistance of experts and non-experts in order to predict the diagnostic and visual quality of these medical videos, respectively. The evaluation of the metrics is based on three major performance metrics that include, correlation between the subjective and objective scores, relative statistical performance and computation time. Results show that the metrics information fidelity criterion (IFC), visual information fidelity-(VIF) and especially pixel based VIF stand out as best performing metrics. Furthermore, our paper reports the performance of HEVC compression on medical videos and according to the results, it performs optimally in preserving the diagnostic and visual quality of WCE videos at Quantization Parameter (QP) values of up to 35 and 37 respectively
A Novel No-Reference Metric for Estimating the Impact of Frame Freezing Artifacts on Perceptual Quality of Streamed Videos
No full textOnline monitoring of multimedia networks is required to ensure seamless and ubiquitous delivery of services to the end users. Quality of multimedia content, such as video streams, often gets degraded due to network losses such as packet loss. Frame freezing artifacts are introduced in a video stream when packet loss or packet delay takes place. Estimating the perceptual impact of these artifacts on quality of experience of end users helps service providers to maintain quality of service. In this paper, we have presented a novel no-reference video quality metric, which measures the impact of frame freezing due to packet loss and delay in video streaming networks. The proposed metric is based on several features that directly impact the quality of experience of end users. These features, including motion characteristics of videos, are calculated using the temporal information between video frames and then combined mathematically to form a video quality metric. Different weights are assigned to different features for better performance of the proposed metric. With detailed experiments, we have shown that our method outperforms other contemporary methods in terms of high accuracy and low computation time in frame freeze detection, low root mean square values, high coefficient of determination, and high correlation between subjective and objective measurements. We have used five video databases for our model's evaluation and validation. Furthermore, we have shown that our method is statistically superior to the other models in comparison
An intrusion oriented heuristic for efficient resource management in end-to-end wireless video surveillance systems
No full textThis paper presents an intrusion oriented heuristic for wireless video surveillance systems that jointly controls the frame rate (FR), spatial or video resolution (VR), and compression level of videos prior to transmission leading to minimum bandwidth and storage consumption. In the proposed model, video streams are transmitted in high quality, with high FR and VR, only when an intrusion is detected, hence saving substantial amount of bandwidth and storage for durations when no intrusion is detected. Results for the proposed model in terms of bandwidth and storage efficiency, using H. 264 and H. 265 video encoders, are also shown
Impulse noise mitigation using precoded SCFDMA for uplink PLC systems
No full textThis article presents a new transceiver structure for uplink power line communication (PLC) system based on single carrier frequency division multiple access (SCFDMA) for the mitigation of inherent PLC noise i.e. impulse noise. Moreover, SCFDMA also promises low PAPR values than the conventional orthogonal frequency division multiple access (OFDMA). Furthermore, this work also suggests the employment of linear precoding via Walsh Hadamard transform (WHT) and Zadoff Chu transform (ZCT) to improve the transceiver performance. Adaptive bit loading is also recommended instead of fixed loading to circumvent the channel impairments. Performance of the proposed transceiver in terms of bit error rate (BER) and peak to average power ratio (PAPR) is evaluated in the form of simulations. Results demonstrate that the proposed transceiver for uplink PLC systems perform better than the conventional transceiver design in the presence of additive white Gaussian noise (AWGN) and impulse noise
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