To enhance the security of Internet of Medical Things (IoMT) systems against cyber threats, we introduce a Multi-Level Blockchain Infrastructure combined with a Differentiated Communication Strategy for real-time medical data transmission, utilizing an embedded hardware setup to provide cost-effective solution for resource-limited environments. The workflow of Multi-Level Blockchain Architecture is proposed, incorporating an embedded hardware-driven K-Nearest Neighbours (KNN) algorithm for diagnosing real-time Electrocardiogram (ECG) signals, with Rivest-Shamir-Adleman (RSA) encryption protocol to secure medical records. The simulations are performed using MIT-BIH arrhythmia and normal sinus rhythm datasets. The feature extraction algorithm, incorporated with optimized KNN model, demonstrated promising results for each emergency classification class. The evaluation metrics for Healthy, E1, and E2 classes showed an accuracy of 91.1%, 88.9%, 84.4%; precision of 78.9%, 100%, 75%; and specificity of 86.7%, 100%, 86.7%, respectively. The feasibility of executing optimized algorithms on Arduino platform is confirmed through computational complexity, execution time, and memory requirement. The proposed system architecture provides a robust solution for enhancing IoMT security, strengthening the confidentiality, integrity, and authenticity of medical data, safeguarding against cyber threats. Additionally, the simple embedded hardware setup offers a user-friendly solution, making it well-suited for resource-constrained surroundings.

In this poster we are proposing our ongoing research work on introducing a novel technique for a secured remote health monitoring system for heart patients. This involves integrating a "Multi-Level Blockchain Infrastructure" to ensure the security of confidential medical records. Also, we are proposing a "Differentiated Communication Strategy" for real-time medical data transmission by employing a KNN Machine Learning Algorithm. Moreover, we are introducing an "Embedded Hardware Based Medical Data Encryption Method" to simplify the computational complexity at the patient's end and to ensure the confidentiality of their medical records.

In this paper, we propose a novel Joint Steganography-Source-Channel Coding (JS2C2) scheme for scalable physiological signal transmission in wireless networks. Our goal is to secure patient's confidential data in medical signal by using Unequally Steganography Embedding and progressively transmit it by Joint Source-Channel Coding, limiting the extent of end to end distortion in the received signal, while abating transmission energy. The main contribution of this paper lies in the inherently joint design of the physiological signal steganography coding and transmission by taking advantage of the unequal importance among different segments of the physiological data. Higher steganography coding level and more robust source-channel coding will protect those highly important segments of the physiological data. Therefore, data integrity and transmission efficiency can be achieved in a resilient way. Simulation results demonstrate that USE attains low distortion (Wavelet-based Weighted Percent Root-mean-squared Difference, i.e. WWPRD2C2.

The continued growth and popularity of IoT-based wearables coupled with wireless body area sensor network (BASN) communication architectures continues to gain widespread adoption for e-Health applications. Challenges facing the adoption of this vision require e- Health communication architectures for wearable IoT/BASNs to make effective use of bandwidth, energy stores for extended continuous transmission of physiological data, mitigation of computational burden when analyzing the data in the cloud at a global scale and, most importantly, ensuring the features of clinical significance in the biomedical signal are not compromised. In this paper, we present a novel physiologically-aware communication architecture to address these challenges for wearable IoT/BASNs for e-Health applications. The architecture works by extracting patient health state using local in-node pre-diagnosis (or pre-screening) to help guide the operation of the communication architecture in deciding when data should be transmitted, its type and format, and given quality. This latter property on preserving signal 'quality' is central to the architecture, which employs a feature-based diagnostic distortion measure to ensure retention of features of clinical significance during source coding in order to guarantee their reconstruction; a notion which carries greater emphasis for biomedical signals as opposed to ordinary multimedia signals. Simulation work of the architecture is presented in MATLAB using Electrocardiograph (ECG) signals from PhysioNet's ECG database, where it is demonstrated energy savings are realized by a factor of 30 with a reduction in biomedical data volume as high as 86% for tested cases while preserving clinical features.

In this paper, an innovative idea of secure and energy efficient electrocardiogram steganography based on Discrete Wavelet Transform (DWT) is proposed, in which different important ECG data are steganographed with variable embedding strengths so that the reconstructed ECG signal quality is preserved. Incorporating the proposed Unequal Steganography Embedding (USE) with Unequal Error Protection (UEP), the proposed scheme further improves transmission performance in terms of ECG signal quality, ensures the confidentiality as well as reliability of a user's data, and makes the transmission more energy efficient. Simulation results demonstrate that USE attains very low distortion (WWPRD less than 0.45 %). Furthermore, high correlation between host and stego ECG and ECG data remains diagnosable after steganography. Based on our literature reviews, the reliability, robustness, and energy efficiency of this proposed method are unmatched in comparison with any other published methods.

In this work, the advantages of coupling biomedical signal compressors with clinical feature-based distortion measures are demonstrated. Such a coupling allow biomedical signal compressors to self-establish hard limits with regards to choices surrounding compression ratios, or `quality settings', a compressor can safely choose from to guarantee that features of clinical significance are protected so that their reconstruction remains clinically relevant. This coupling allows biomedical signal compressors to operate in an unsupervised manner, since it is demonstrated that establishing hard limits that are applied equally to all signals does not allow one to maximize and/or strike a balance between compression ratio and signal fidelity. Such mechanisms can be employed in communication architectures in wearable body area sensor networks (BASNs) for emerging Internet of Things (IoT) applications for autonomous tasks. While feature-based distortion measures such as the Clinical Distortion Index (CDI), and the Weighted Distortion Measure (WDD) already exist, we demonstrate the viability of our work by proposing a generalizable feature-based distortion measure we call the Diagnostic Distortion Measure (DDM), which offers several benefits that address a few shortcomings present in the CDI and WDD in real-time applications for unsupervised self-guided compressors. Experimental results show successful application of our DDM with ECG signals from the PhysioNet database.

With rapid development in mobile devices with high quality image and video processing capabilities, it is desirable or necessary to implement steganography technology within such devices in some applications such as source authentication. In this paper, we propose a method of implementing information hiding within a video with less processing time and memory requirement. The message to be secretly communicated is hidden in the video by modifying blocks of Discrete Wavelet Transform coefficients of feature regions. We choose corners as specific features. The localizable capability of both corner detection algorithm and the Discrete Wavelet Transform makes it possible for the entire embedding method to be localized. This makes the entire process of steganography computationally faster and memory efficient. Our simulations show that the proposed method has a processing time that is up to 2.6 times more efficient, in average, than other traditional methods without incurring memory overhead.

Lost audio packet steganography (LACK) is a steganography technique established on the VoIP network. LACK provides a high-capacity covert channel over VoIP network by artificially delaying and dropping a number of packets in use to convey stegnogram. However, the increasing loss of packets will hurt the quality of the VoIP service. The quality deterioration will not only affect the legitimate VoIP service but also constrain the capacity of the covert channel. Discrete spring transform (DST) is proven to be a way to eliminate the perceptual redundancy in the multimedia signal. In this paper, the DST is applied on the LACK so that the perceptual redundancy of the voice frames is suppressed. In this way, the less redundant VoIP frames with perceptual equivalent quality can be transmitted in a channel whose capacity is squeezed by the established covert channel. As a result, the VoIP perceptual quality can be maintained with the existence of the covert channel. Meanwhile, the proposed DST-based method demonstrates the possibilities in exploiting the perceptual space of the multimedia signal. The simulation results show that the DST on LACK achieves up to 24 % more capacity over the LACK scheme.

Digital audio signal provides a large capacity for embedding hidden messages using digital steganography techniques. How to prevent hazardous steganography embedding on the Internet becomes an important task in the field of network security. For the Internet environment, the steganography attack method is required to be generic and real time. An active warden-based attack method is potential to be a generic method for the steganography attack. A discrete spring transform (DST)-based generic active warden steganography attack framework has been proposed by us. In this paper, based on the DST, a real-time steganography attack method is proposed. The potential unauthorized hidden message is removed in a real-time manner when uploading or downloading the audio signal. The real-time signal perceptual quality control is achieved by the automatic feedback from the objective audio quality evaluation model. The attack parameters are adaptively changed to reach a balance between the attack performance and the audio signal quality. The simulation results validate the proposed method in terms of the steganography attack performance and the audio signal quality after the attack. Copyright © 2014 John Wiley & Sons, Ltd.

There have been many robust image steganography methods that are invented in recent decades. However, this technique also may be used by malicious users to transmit dangerous information through the Internet beyond the control of the security agencies. How to detect and/or block potentially dangerous information transmission on the Internet through billions of images while not affecting the normal digital images becomes a challenging problem. Existing steganalysis methods or steganography attacking methods cannot be used for analyzing a large volume of digital images in a short time. In this paper, we propose an effective steganography attacking method that is not limited by the types of the steganography method. The proposed method can process the digital images to remove the potentially dangerous hidden information while keeping the digital image in a high visual quality. Inspired by the way in which printers and scanners work, our method decouples the human visual perception and the digital image's numerical values. It causes the numerical values of the image to change dramatically, and then the hidden information are largely damaged, while at the same time, the visual image quality can be maintained. Our experimental results have demonstrated that the peak signal-to-noise ratio of images can be above 32dB while the stego data are destroyed. Copyright © 2016 John Wiley & Sons, Ltd.

In order to prevent harmful secret information sharing by steganography, a new active-warden countermeasure approach against steganography is proposed in this paper. Differently from the other countermeasure approaches presented in current literature which need to have some knowledge of the steganographic algorithms to be attacked, our proposed method is a generic method which is independent of any particular steganography methods being utilized. In other words, our approach blindly attacks the steganography without any prior knowledge of the used algorithms or their existence. In general, the hidden information is embedded in a carrier by adjusting the coefficients of the audio or image. In our method, by exploiting the large margin between the numerical value and visual perception of the images, large amounts of visually non-detectable distortions are incurred in the image. As a result, the hidden message is destroyed by this method while the perceptual quality of the image is maintained. Inspired by the print-scan process in which most of the steganographic methods cannot survive, a transform called Discrete Spring Transform (DST) is proposed in this paper as the foundation of our attack algorithm. An image geometrization method is also developed to reconstruct the image in this paper. The simulation results have demonstrated that the PSNR of the attacked image is above 30dB with a high perceptive quality while the BER of the hidden steganographic message in the attacked image is above 0.5.

In wireless sensor networks, nodes periodically wake up and sleep in order to reduce their energy consumption. One challenge in this scenario is how to coordinate the sender and receiver so that they can wake up and sleep at the same pace to maintain connectivity. In this paper, we present a synchronization method that has very low energy consumption overhead yet high-precision synchronization performance. Different from existing synchronization methods, it does not need to correct the offsets and skews of the clocks of nodes. Instead, our proposed method takes advantage of the fact that the time interval between two transmitted beacons is the same as the time interval between two received beacons, since the propagation and coding delay can be assumed to be similar in these two transmissions. Thus, the receiver and the sender can be synchronized using their individual clocks. Based on this key idea, our synchronization method can overcome the offset and drift issue without modifying the clocks. This paper focuses on the theoretical analysis to evaluate this proposed method. The closed-form expression of the error limits for our method has been obtained. Also, the correctness of the theoretical analysis has been verified by our experimental results.

The growth of the Internet and online social media, especially in recent years, also gave rise to a proliferation of online multimedia content creation and distribution. The use of modern steganography methods - the art of hiding information within multimedia - presents an unprecedented opportunity for malicious uses of these materials. Therefore, developing an effective technique to avoid the distribution of secret data is a significant problem that is addressed in this paper for digital images. We introduce a novel algorithm to remove the steganography information embedded in an image without changing the quality of the image and with no prior knowledge of the utilized steganography technique. Our new algorithm called Adaptive Threshold Displacement (ATD) is applied to images in the spatial domain. ATD divides the whole image into different segments and within a given segment, some pixels are displaced according to their contents as well as their neighboring pixel values. For evaluating the effectiveness of our proposed algorithm, we apply ATD to different images that contain hidden information, embedded using two different widely used steganography techniques. The presented results show that virtually all of the hidden information is destroyed by our proposed ATD algorithm, with a retrieval BER of over 40% in average. However, the quality of the images does not change and the PSNR of the resulting images is above 32 dB.

In this paper, we present and investigate a method to multimedia steganography removal methodand remove multimedia steganography in digital audio data. Among the existing steganography methods that can be used to hide secret data in digital audio carriers, the Spread Spectrum methods are among the most effective and robust for embedding steganography data. Though there are currently a few research efforts on removing or destroying steganography in multimedia, there have been very few efforts on removing steganography from audio. In this paper, we have introduced a simple but very effective anti-steganography approach for removing hidden information from digital audio data embedded using Spread Spectrum methods. The main concept in our approach is to leverage limited pseudo-random shuffling of the samples in the audio stream so that the synchronization information necessary for decoding Spread Spectrum steganography information cannot be attained. Our simulation results in this paper have demonstrated great performance in removing audio steganography by achieving a 50% bit error rate after applying our anti-steganography approach to the digital audio data while maintaining the audio quality.

Digital steganography is often divided into two categories of research: steganographer and attacker, where a steganographer attempts to successfully hide the existence of hidden data and an attacker attempts to uncover and destroy said data. Often steganographic attacks utilize passive techniques, where the attacker monitors messages and alters or destroys the cover media only if the media is suspected to contain a message. Passive attacks are much more prevalent than active attacks for a variety of reasons. Generally passive attacks are more efficient and effective in determining the existence of hidden data in a given cover media, however, most passive attacks are not generic enough to detect the presence of a hidden message outside of a very small subset of steganographic algorithms. Conversely, current active attacks are very cost effective and often severely degrade or destroy the quality of the cover media. In this paper, we propose a novel active steganographic attack called the Discrete Spring Transform (DST). The concept of the DST attack is that of likening the cover media to a spring, in that it can be physically altered or manipulated in a manner of ways, while the basic structure and integrity of the spring is preserved despite these alterations. Since many steganographic schemes rely on the fact that the cover media remains somewhat stable the DST is effective in destroying the stego media for such types of steganographic algorithms. It follows that the DST is an effective and highly adaptable active attack that can be applied to a variety of cover media, including video. We will demonstrate that the attack is capable of defeating next-generation steganographic algorithms, including motion-vector steganography and RST-resilient algorithms by increasing the Bit Error Rate (BER) of the steganographic algorithm to approximately 0.5 while maintaining the quality of the cover media, where the Peak Signal-to-Noise Ratio (PSNR) of the image-derived media always remains above 30db.

The significant development of cell phone and mobile network in recent years leads to some security concerns caused by increasing capacity of the networks and the large margin of the multimedia data. Audio steganography is a proven way to hide information in digital audio signals, where many schemes have been effective at hiding large amounts of data. In order to prevent the malicious threat of the audio steganog-raphy, the countermeasure of audio steganography is also an important topic. In this paper, we propose a novel steganographic attack which can defeat audio steganography algorithms while maintaining an acceptable audio distortion level. The attacking method is based on a proposed transform called discrete spring transform. Similar to the time scale modification, the spring transform disables the synchronization of the hidden information. Furthermore, the proposed method has some advantages over the traditional time scale modification, therefore the steganography method which can resist to the time scale modification still can be defeated by the proposed method. The simulation results show that the proposed method successfully defeat some audio steganography methods which are resistant to the time scale modification with subjective auditory quality score no worse than -0.1.

In this paper, we have investigated Covert Channels in 3GPP LTE-A (Long Term Evolution-Advanced) for identifying headers and extension fields where covert data can be hidden in covert communications. We also discuss the covert channel capacity for LTE-A where the specific fields in the headers of the MAC (Medium Access Control), RLC (Radio Link Control) and PDCP (Packet Data Convergence Protocol) layers are analyzed. We review different scenarios of channel coding rate, modulation schemes and channel bandwidths and present our results.

In this paper, we introduce a novel algorithm to destroy the steganographic information embedded in an image without changing the quality of the image and with no prior knowledge of the used steganography scheme. We propose the new Neighbor Class Displacement (NCD) algorithm, which arranges the pixels of an image into a given number of classes. The elements of two specific classes are substituted with each other based on different conditions related to the content of the class elements. For evaluating the effectiveness of our attack, we apply NCD to different steganographically modified images to remove the embedded hidden information. Our results show that over 40% of the steganography bits are toggled in natural images by our proposed attack algorithm, which means the hidden information is removed effectively. Additionally, the visual quality of the images does not change and the PSNR of the original and attacked images is above 32 dB. We compare our attack to other signal processing and geometrical attacks and show that our NCD scheme outperforms other steganography attack algorithms while maintaining the quality of the host image.

Watermarking is one of the most effective tools to countering multimedia content tampering and digital piracy. However, due to widespread availability of watermarking tools and the ease of distribution via Internet, the misuse of watermarking algorithms adapted to distribute malicious information as well as industrial and government secrets is not only possible but prevalent. Therefore, it becomes critical that such embedded data be removed from the multimedia without degrading the quality. In this paper, we propose a general removal method to remove watermarks from images based on pseudorandom desynchronization by selective pixel removal. This method does not assume nor require any prior information about image, watermark or embedding algorithm. We have shown that our method can achieve on average a 50% BER, effectively removing all watermark information without degrading the visual quality of the images.

In this paper, we propose a fast, simple and efficient image codec applicable for embedded processing systems. Among the existing image coding methods, wavelet quad-tree is a foundation leading to an efficient structure to encode images. By searching significant coefficients along quadtrees, an embedded efficient code can be obtained. In this work, we exploit hierarchical relations of the quad-tree structure in terms of searching entropy and present a quadtree searching model that is very close to the searching entropy. By applying this model, our codec surpasses SPIHT [1] by 0.2-0.4 db over wide code rates, and its performance is comparable to SPIHT with arithmetic coding and JPEG2000 [2]. With no additional overhead of arithmetic coding, our code is much faster and simpler than SPIHT with adaptive arithmetic coding and the more complicated JPEG2000 algorithms. This is a critical factor sought in embedded processing in communication systems where energy consumption and speed are priority concerns. Our simulation results demonstrate that the proposed codec is about twice as fast with very low computational overheads and comparable coding performances than existing algorithms.

Joint exploration of intra/inter-video coding versatility in signal processing domain and signature/hash diversity in the information security domain has not been well investigated in the literature. In this paper, we show multimedia stream authentication quality can be improved significantly by exploring these diversities. Specifically, we propose a new rate distortion framework by considering intra/inter-signature/hash diversity to simultaneously provide video service quality, communication rate efficiency and video content integrity for wireless video streaming. This research aims to provide a unique fusion of inter/intra video coding versatility and signature/hash authentication diversity to provide video authentication and traffic control. The results based on simulations demonstrate the effectiveness of the proposed scheme in achieving video robust authentication quality with limited rate constraint.

Reducing transmission energy consumption is one of the most critical research issues in the area of Wireless Sensor Networks (WSNs). In this paper, we present our scheme for employing collaborative signal enhancement to achieve energy efficient image transmissions in WSNs. A collaborative signal enhancement approach is compelling due to its capability of saving individual energy consumption by spreading total transmission consumption over multiple sensors. Individual packets describing an embedded wavelet-encoded image exhibit a significantly unequal contribution towards image quality. By leveraging this fact we develop a strategy of appropriately selecting the number of collaborative sensors for each packet transmission in order to achieve the highest possible image quality given a restricted transmission energy consumption budget. Experimental results show that our proposed approach can provide about 2dB higher image quality under the same energy budget compared with the state-of-the-art collaborative transmission scheme in WSN literature.

In this paper, we propose an innovative low-cost biometric authentication scheme based on uniformed Gaussian mixture model (GMM) for secure communications within wireless body area sensor networks (WBASNs), to obviate the cost-prohibitive key exchange problem. In this approach, the sender Inter Pulse Interval (IPI) information is selected as the biometric key for authentication, and a statistical based signing scheme is developed using the uniformed GMM. Experimental analysis shows that the proposed approach effectively protects the communication channels in WBASN with a low computational complexity, significantly removing the need for secret key exchange and critical time synchronization overheads.

In this paper we present a novel approach that leverages overlap regions of images from different wireless sensors for mutual authentication of the transmitted images. We present our theoretical analysis for this approach and derive the authenticity ratio for a binary symmetric channel. Our results show that by selecting appropriate authenticity constraints and appropriate numbers of overlap region packets, a significant improvement of the authentication success probability can be achieved compared to traditional image authentication approaches.

Wireless multimedia sensor networks (WMSNs) support many acoustic applications for audio surveillance, animal tracking/vocalization, human health monitoring, etc. However, resource constraints in sensor networks (such as limited battery power, bandwidth/computation capability, etc.) pose challenges for the quality and security of audio data transmission and processing. The security is a critical issue since audio information can be accessed or even manipulated in WMSNs. In order to ensure security, audio quality and energy efficiency, we propose an index-based selective audio encryption scheme for WMSNs. The scheme protects data transmissions by incorporating both resource allocation and selective encryption based on modified discrete cosine transform (MDCT). In this proposed scheme, the audio data importance is leveraged using the MDCT audio index, and wireless audio data transmission proceeds with energy efficient selective encryption. The simulation results show that the proposed approach offers a significant gain in terms of energy efficiency, encryption performance and audio transmission quality.

Selective encryption for video streaming was proposed for efficient multimedia content protection. However, the issues on joint optimization of video quality, content protection, and communication energy efficiency in a wireless sensor network (WSN) have not been fully addressed in the literature. In this paper, we propose a scheme to optimize the energy, distortion, and encryption performance of video streaming in WSNs. The contribution of this work is twofold. First, a channel-aware selective encryption approach is proposed to minimize the extra encryption dependency overhead at the application layer. Second, an unequal error protection (UEP)-based network resource allocation scheme is proposed to improve the communication efficiency at the lower layers. Simulation experiments demonstrate that the proposed joint selective encryption and resource allocation scheme can improve the video transmission quality significantly with guaranteed content protection and energy efficiency.

Media integrity, transmission quality, and energy efficiency are critical for secure wireless image streaming in a wireless multimedia sensor network (WMSN). However, conventional data authentication and resource allocation schemes cannot be applied directly to WMSN due to the constraints on limited energy and computing resources. In this paper, we propose a quality-driven scheme to optimize stream authentication and unequal error protection (UEP) jointly. This scheme can provide digital image authentication, image transmission quality optimization, and high energy efficiency for WMSN. The contribution of this research is two-fold as summarized below. First, a new resource allocation-aware greedy stream authentication approach is proposed to simplify the authentication process. Second, an authentication-aware wireless network resource allocation scheme is developed to reduce image distortion and energy consumption in transmission. The scheme is studied by unequally protected image packets with the consideration of coding and authentication dependency. Simulation results demonstrate that the proposed scheme achieves a performance gain of 3 ~ 5 dB in terms of authenticated image distortion.

A cross layer Unequal Error Protection (UEP) scheme based upon the multimedia position-value (P-V) partitioning has been recently proposed to only improve energy-distortion performance in Wireless Multimedia Sensor Networks (WMSN). There is also a great potential to adapt this UEP scheme into multimedia stream integrity protection. However, performance gains in multimedia transmissions with considerations of energy, distortion, and authentication in WMSN is a challenge. This difficulty results from the media codec dependency on both the content of multimedia stream authentication and protection on the integrity process itself. In this article, we propose a novel scheme which optimally matches the application layer multimedia codec dependency to both lower layer resource allocation requirements and the upper layer stream authentication. The goal of this scheme is to optimize the integrity and quality performance gain within energy constraint. The contribution of the proposed approach is two folds. Firstly, a stream authentication scheme matched with P-V codec dependency is proposed which significantly reduces additional authentication dependency overhead. Secondly, a new resource allocation scheme is proposed to improve energy-distortion-authentication performance with regard to codec dependency. Simulation studies demonstrate that the proposed scheme significantly impacts achieving multimedia transmission quality with energy efficiency and authentication assurance.

Transmissions of large sized images can be a bottleneck for a wireless sensor network (WSN) due to its limited resources. Security can be another concern. This paper proposes a collaborative transmission scheme for image sensors to utilize inter-sensor correlations to decide the transmission and security sharing patterns based on the path diversities. Our proposed approach for secret image sharing on multiple node-disjoint paths for image delivery is to achieve high security without any key distribution and management, and thus the key management related problems do not exist. The energy efficiency is another major contribution made in this paper. This scheme does not only allow each image sensor to transmit optimal fractions of overlapped images through appropriate transmission paths in an energy-efficient way, but also provides unequal protection to overlapped image regions by path selections and adaptive bit error rate (BER) requirement. The simulation results show that the proposed scheme can achieve considerable gains in terms of network lifetime extension, image transmission security enhancement, image quality improvement, and energy efficiency for wireless sensor networks.

Distributed Source Coding (DSC) is an effective means in reducing data redundancy in Wireless Sensor Networks (WSNs). However, the issues on designing multirate DSC with multirate transmission in WSNs have not been well addressed in the literature. In this paper, we propose a cross-layer approach to achieve optimal DSC data quality while assuring energy efficiency and latency requirement through adjusting multirate DSC data dependencies and network multirate transmission parameters jointly. Specifically, the DSC coding dependency among multirate source coding sensors are fine-tuned to balance compression efficiency and transmission robustness. Transmission rate and retransmission limit on each wireless link are optimized accordingly to achieve Unequal Error Protection (UEP) among inter-dependent DSC streams. Simulation studies demonstrate that the proposed scheme ensures satisfactory DSC data quality and energy efficiency.

Abstract In this paper, we propose an innovative adaptive secure image delivery approach, to achieve effective and efficient image encryption based on an optimal transmission rate in terms of energy efficiency in wireless sensor networks (WSN). Our contribution is three folds—First, the proposed component based selective encryption scheme achieves high image security, while incurring little encryption overhead; furthermore, the proposed adaptive encryption scheme achieve the best security effort within delay bound; finally, the proposed transmission rate optimization improves energy efficiency, and feeds back effective path capacity parameters for adaptive encryption. Simulation results show a significant gain in both energy efficiency and security based on the proposed approach for image secure transmissions in WSN. Copyright © 2007 John Wiley & Sons, Ltd.

Multimedia delivery over Wireless Sensor Networks (WSNs) is energy critical. In this paper, we study an energy constrained cross layer optimization scheme to improve digital image quality in cross polarization discrimination (XPD) based Multiple Input Multiple Output (MIMO) WSNs. The contribution of this research can be summarized in three parts. First, link layer energy consumption and packet loss ratio in multirate XPD based MIMO WSN are modeled. Secondly, XPD based modulation optimization cross link and physical layer is proposed, achieving considerable energy efficiency. Finally, a new Position-Value (P- V) based Unequal Error Protection (UEP) scheme is studied and discussed in XPD MIMO WSNs, with more efficient resource allocation compared to traditional approaches. Simulation results show the proposed modulation optimization scheme improves energy efficiency considerably, and position based UEP achieves significant distortion-energy gain compared with traditional layer based resource allocation schemes in XPD MIMO WSNs.

A secure image transmission mechanism is necessary when malicious intruders intend to access and modify content delivery over wireless networks. To assure data integrity, authentication is required for multimedia data delivered over wireless image sensor networks. Watermarking technique is an effective vehicle to assert and assure the image data authentications. There have been recent works reported on watermarking, but few with the consideration of energy cost in terms of the data communication and processing, which is a key constraint to many embedded systems and wireless sensor networks. Most watermarking systems only target at minimizing watermarked image distortion and increasing robustness at the source coding site for lossy image processing. The watermarked image distortion caused by error-prone wireless environments during transmission has not been fully considered. In this paper, an innovative energy-aware adaptive watermarking scheme for realtime image delivery is proposed in wireless multimedia sensor networks. This new scheme allocates network resource to protect the watermarked image transmission while embedding watermark coding redundancies into the images. Dynamic watermark thresholds are applied to be adaptive to the network condition (packet loss ratio) and the inter-frame correlation is exploited to reduce processing delay. The simulation results show that the proposed adaptive watermark system can achieve considerable energy efficiency and assure the data integrity.

Joint consideration of energy efficiency, multimedia quality and media authenticity has largely been overlooked in the studies of secure wireless multimedia streaming. In this paper, we propose an authentication - resource allocation framework for secure transmission of multimedia streaming over energy constrained wireless networks. The contributions of this research can be summarized in three aspects. Firstly, a hash chain based stream level authentication scheme compatible for JPEG2000 compression standard is proposed. Secondly, link layer energy- distortion is modeled, and the energy-distortion convex hull is efficiently identified, which significantly reduces optimization complexity. Finally, an authentication oriented resource allocation scheme is proposed based on the proposed authentication scheme and link layer energy-distortion convex hull, where the authenticated image quality is optimized according to energy budget constraints.

Image transmissions in Wireless Multimedia Sensor Networks (WMSNs) are often energy constrained. They also have requirement on distortion minimization, which may be achieved through Unequal Error Protection (UEP) based communication approaches. In related literature with regard to wireless multimedia transmissions, significantly different importance levels between image-pixel-position information and image-pixel-value information have not been fully exploited by existing UEP schemes. In this paper, we propose an innovative image-pixel-position information based resource allocation scheme to optimize image transmission quality with strict energy budget constraint for image applications in WMSNs, and it works by exploring these uniquely different importance levels among image data streams. Network resources are optimally allocated cross PHY, MAC and APP layers regarding inter-segment dependency, and energy efficiency is assured while the image transmission quality is optimized. Simulation results have demonstrated the effectiveness of the proposed approach in achieving the optimal image quality and energy efficiency. The performance gain in terms of distortion reduction is especially prominent with strict energy budget constraints and lower image compression ratios.

The advancement in Distributed Source Coding (DSC) for mission-driven wireless sensor networks (WSNs) has opened a new vista for its wide applications in multiple correlated sensor networks such as real time target tracking and environment monitoring. The features of the DSC applications offer many potential opportunities for sensor networks to utilize multirate transmissions for network performance enhancement. In this paper, we propose a methodology for cross-layer optimization between routing and DSC in WSNs, and we introduce a multirate based routing scheme for mission-driven DSC applications that can considerably extend network lifetime. The proposed scheme adopts the rate assignment based on residual energy and employs a joint rate and energy scheduling mechanism to meet the end-to-end transmission rate demand, information precision requirement, and energy constraints in the networks adopting DSC. This approach is different from the traditional multirate research in link adaptation, where the focus was to increase channel throughput based on rate adaptation from variable channel conditions. The objective of this work is not to utilize multirate for increasing channel throughput, but to exploit multirate capability for routing optimization in DSC based applications with consideration for energy consumption. We also introduce the concept of "Energy Usage Scheduling (EUS)" to optimize the energy usage based on the rate constraints and DSC application needs. Simulation results show that the proposed scheme can achieve a significantly longer network lifetime than that reported in the literature.

Many Sensor applications such as monitoring and surveillance may require image sensor array to conduct collaborative image transmissions in Wireless Sensor Network (WSN). The large size image transmission in WSN is a bottleneck due to the limited energy resources. In this paper, we propose an optimal scheme for image sensors to utilize inter-sensor correlations to decide transmission patterns based on a Multi-Rate Least Cost Path (MRLCP) routing scheme, which achieves high energy efficiencies and longer network lifetime. This optimization scheme allows each image sensor to transmit optimal fractions of the overlapped images through appropriate ratebased routing paths. A specific genetic algorithm is designed to solve such discrete optimization problem. The simulation results show that the proposed image transmission scheme can achieve considerable gains in terms of the WSN energy efficiency and network lifetime extension.

Many sensor applications such as monitoring and surveillance may require image sensor array to conduct collaborative image transmissions in wireless sensor networks (WSN). The large size image transmissions cause bottlenecks in WSN due to the limited energy resources and network capacity. In this paper, we propose a collaborative transmission scheme for image sensors to utilize inter-sensor correlations to decide transmission patterns based on transmission path diversities, which achieves minimal energy consumption, balanced sensor lifetime and required image quality. This optimization scheme not only allows each image sensor to transmit optimal fractions of the overlapped images through appropriate transmission paths in energy-efficient way, but also provides unequal protection on the overlap image regions through path selections and resource allocations to achieve good transmission image quality. The simulation results show that the proposed image transmission scheme can achieve considerable gains in terms of the network lifetime extension, image distortion reduction, and energy efficiency.

In image transmission applications over wireless sensor networks (WSN), energy efficiency and image quality are both important factors for joint optimization. In this paper, we propose a new position-value (P-V) oriented cross layer optimization approach to minimize energy consumption with distortion bounds for image transmission applications in WSN, by exploring importance level diversity for position-magnitude information. To put more effort on transmitting important position information and relatively less effort on unimportant magnitude information, desirable BER, ARQ retry limit, transmission rate and distortion reduction of image are jointly optimized cross PHY, MAC and APP layers, and image quality is assured while energy consumption is minimized. Simulation results demonstrate the effectiveness of the proposed approach in achieving energy efficiency while maintaining image quality.

Recent advances in distributed source coding (DSC) for mission-driven wireless sensor networks (WSN) are related to the coding for multiple correlated sensors in applications such as real time target tracking and environment monitoring. The characteristic of these DSC applications provides significant potential opportunities in the associated sensor network to utilize multirate transmissions for enhancing network performance. In this paper, we study a methodology for interplay optimization between routing and DSC in WSN, and propose a novel multirate based routing scheme for mission-driven DSC applications that considerably extends network lifetime. The proposed scheme adopts the rate assignment based on the residual energy, and employs a joint rate and energy scheduling mechanism to meet the end-to-end transmission rate constraint, information precision requirement, and the energy constraints in the network for DSC. Simulation results show that this multirate based routing scheme achieves significantly longer network lifetime compared to other existing research in WSN for DSC applications.

Many Sensor applications such as monitoring and surveillance may require image sensor array to conduct collaborative image transmissions in Wireless Sensor Network (WSN). The large size image transmission in WSN is a bottleneck due to the limited energy resources. In this paper, we propose an optimal scheme for image sensors to utilize inter-sensor correlations to decide transmission patterns based on a Multi-Level Rate-Oriented routing (MLRR) routing scheme, which achieves high energy efficiencies and longer network lifetime. This optimization scheme allows each image sensor to transmit optimal fractions of the overlapped images through appropriate multiple Rate-Oriented routing paths. The simulation results by using GA algorithm show that the proposed image transmission scheme can achieve considerable gains in terms of the WSN energy efficiency and network lifetime extension.

Selective encryption for secure image transmission is an important ongoing research area which aims to scramble the critical information correlation and inter-dependency within final image compression bit streams. However, how to take Unequal Error Protection (UEP) method for transmitting partially encrypted image data in error-prone communication channels is still an open research problem in Wireless Sensor Networks (WSN). In this paper, we propose a new cross layer optimization approach for energy efficient delivery of selectively encrypted images in WSN while assuring image quality. In the proposed approach, identified importance levels of diversity for encrypted procession blocks as well as position-value (P-V) information are extensively explored within image compression and encryption bit streams. Desirable BER, ARQ retry limit, transmission rate are jointly optimized across PHY, MAC and APP layers regarding the image distortion reduction bound and communication energy efficiency. Both image quality and security are assured while energy consumption is minimized. Simulations results have shown significant gain in image security assurance and transmission quality achievement with energy efficient communications in WSN.

This paper proposes a new tiered heterogeneous wireless image sensor network for real-time unobtrusive species detection and video cataloguing based on a new hierarchically scalarized-character oriented detection (HIS-CODE) algorithm and architecture. An experimented test bed has been set up at the Omaha Henry Doorly Zoo, and data collected over wireless network from this test bed has been processed and classified based on the proposed HIS-CODE. This work contributes to a novel integration in wireless sensor networks with the in-network distributed image recognition functionality, especially with the consideration of wildlife species image recognitions.

Image sensors' digital transmissions are significant challenge to the Wireless Sensor Networks (WSN) due to resource constraints. In this paper, we propose a novel position-value (P-V) oriented multirate image transmissions approach called Image Component Multirate Transmissions (ICMT) over WSN. This method adapts different reliable levels of transmissions to various P-V segmented components within the compressed image bit stream. Simulation results show that the proposed scheme achieves high energy efficiency in WSN while enhancing the image transmission quality.

Signal processing applications such as Distributed Source Coding (DSC) in Wireless Sensor Network (WSN) are often multirate in nature, which provide additional significant opportunities in WSN design for achieving energy efficiency. In this paper, we analyze the DSC traffic for signal processing applications in multirate WSN and propose a novel rate oriented approach with MAC and PHY cross layer utilization to achieve high energy efficiency. Simulation results show that the proposed approach achieves significant energy efficiency by a factor of three while maintaining the transmission quality in WSN. This approach can be easily extended to other WSN MAC and PHY designs, providing multirate service to application layer to allow achieving higher energy efficiency

Distributed source coding (DSC) based signal processing applications involve data transmissions at multirates in wireless sensor network (WSN). In this paper, we propose a novel cross layer approach in WSN to achieve energy efficiency using multirates desirable for the DSC based signal processing applications and current network conditions. Our approach can be summarized into two parts: first, energy efficient multirate MAC-PHY supporting DSC applications; and second, rate oriented interaction of MAC-PHY and DSC applications. Multirate MAC-PHY utilizes desirable bit error rate (BER), channel attenuation, corresponding modulation schemes, and multirate requirements, to determine the minimum desirable transmission power. Rate oriented interaction provides optimal transmission rates feedback to interact with DSC applications, making DSC applications adaptively adjust information coding rate according to network conditions. This interactive approach achieves further energy saving significantly by making the DSC application aware of WSN conditions. Besides DSC, this work can be easily extended to other multirate signal processing applications in WSN.

The designs of application specific integrated circuits and/or multiprocessor systems are usually required in order to improve the performance of multidimensional applications such as digital-image processing and computer vision. Wavelet-based algorithms have been found promising among these applications due to the features of hierarchical signal analysis and multiresolution analysis. Because of the large size of multidimensional input data, off-chip random access memory (RAM) based systems have ever been necessary for calculating algorithms in these applications, where either memory address pointers or data preprocessing and rearrangements in off-chip memories are employed. This paper establishes and follows novel concepts in data dependence analysis for generalized and arbitrarily multidimensional wavelet-based algorithms, i.e., the wavelet-adjacent field and the super wavelet-dependence vector. Based on them, a series of novel nonlinear I/O data space transformations for variable localization and dependence graph regularization for wavelet algorithms is proposed. It leads to general designs of non-RAM-based architectures for wavelet-based algorithms where off-chip communications for intermediate calculation results are eliminated without preprocessing or rearranging input data.

Although the notion of the parallelism in multidimensional applications has existed for a long time, it is so far unknown what the bound (if any) of inter-iteration parallelism in multirate multidimensional digital signal processing (DSP) algorithms is, and whether the maximum inter-iteration parallelism can be achieved for arbitrary multirate data flow algorithms. This paper explores the bound of inter-iteration parallelism within rate-balanced multirate multidimensional DSP algorithms and proves that this parallelism can always be achieved in hardware system given the availability of a large number of processors and the interconnections between them.

In wireless sensor networks, each sensor node is normally powered by batteries without replenish. Radio operations of a sensor node is a big user of the limited energy. This situation is further exaggerated by retransmissions caused by a time-varying channel. Therefore, how to design an energy efficient sensor MAC is one of the most important issues in sensor networks. Unlike other reported work utilizing a fixed frame size, we propose a new approach to enhance the energy efficiency by introducing an optimal frame size predictor into the sensor MAC, combating the unfavorable time-varying channel quality. We also propose a new sensor MAC to balance goodput performance and energy efficiency, as well as keep fairness among different nodes. Simulation results show that the proposed sensor MAC can largely reduce the average number of transmissions. Therefore, the energy efficiency can be improved by at least 10%, still keeping the same good throughput performance. The proposed sensor MAC can be easily implemented in practical.