Resource management (RM) is a critical action in systems with limited resources such as sensor networks. Efficient RM depends heavily upon the availability of accurate information on the state of available resources. ...
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ISBN:
(纸本)9781479913534
Resource management (RM) is a critical action in systems with limited resources such as sensor networks. Efficient RM depends heavily upon the availability of accurate information on the state of available resources. However, exchange of state information incurs an overhead on the system. In this paper, the sensing and computing resource management in sensor networks is considered. A lossless, distributedsource-coding framework is presented to model the exchange of state information. The framework enables the characterization of the interplay between the performance and overhead of RM by leveraging the correlation among the state information of various nodes. Moreover, the proposed framework enables an improved estimate of the lower bound for the minimum control overhead necessary to accurately describe the state of nodes in the network. This improvement is achieved by exploiting the correlation among the state information of nodes as well as the available information on prior resource allocation actions as side information.
The ability to efficiently switch from one pre-encoded video stream to another is a valuable attribute for a variety of interactive streaming applications, such as switching among streams of the same video encoded in ...
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ISBN:
(纸本)9781479923410
The ability to efficiently switch from one pre-encoded video stream to another is a valuable attribute for a variety of interactive streaming applications, such as switching among streams of the same video encoded in different bit-rates for real-time bandwidth adaptation, or view-switching among videos capturing the same dynamic 3D scene but from different viewpoints. It is well known that intracoded I-frames can be used at switch boundaries to facilitate streamswitching. However, the size of an I-frame is large, making frequent insertion impractical. A recent proposal towards a more efficient stream-switching mechanism is distributed source coding (DSC), which exploits worst-case correlation between a set of potential predictor frames in the decoder buffer (called side information (SI) frames) and a target frame to lower encoding rate. However, the conventional use of bit-plane and channel coding means the encoding and decoding complexity of DSC frames is large. In this paper, we pursue a novel approach to the stream-switching problem based on the concept of "signal merging", using piecewise constant (pwc) function as the merge operator. Specifically, we propose a new merge mode for a code block, where for each k-th transform coefficient in the block, we encode appropriate step size and horizontal shift parameters at the encoder, so that the resulting floor function at the decoder can map corresponding coefficients from any SI frame to the same reconstructed value, resulting in an identically merged signal. The selection of shift parameter per coefficient, as well as coding modes between intra and merge per block, are optimized in a rate-distortion (RD) optimal manner. Experiments show encouraging coding gain over a previous implementation of DSC frame at low-to mid-bitrates at reduced computation complexity.
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 tr...
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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.
A novel codeword quantization algorithm based on message-passing using a low density generator matrix formulation is proposed and analyzed. The scheme is a seemingly subtle variant on a recently proposed "truthin...
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ISBN:
(纸本)9781467352390;9781467352376
A novel codeword quantization algorithm based on message-passing using a low density generator matrix formulation is proposed and analyzed. The scheme is a seemingly subtle variant on a recently proposed "truthiness" propagation algorithm, but one which affords a more explicit connection to a modified Bethe free energy function. Applications to distributedcoding in sensor networks are also included in the simulation examples, where the algorithm is observed to outperform conventional LDPC belief propagation decoding using side information, in a practical setting when the reliability of the side information diminishes.
In this paper, we study the problem of correlated data gathering in wireless sensor networks. An opportunistic routing protocol joint with opportunistic network coding is proposed for correlated data gathering. In ord...
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ISBN:
(纸本)9781467361873
In this paper, we study the problem of correlated data gathering in wireless sensor networks. An opportunistic routing protocol joint with opportunistic network coding is proposed for correlated data gathering. In order to reduce the total transmission, we introduce the expected number of coded transmission (ECTX) as metric for the routing selection. Moreover, we also define the coding gain for the network nodes to count the coding opportunistic, with which the throughput of the wireless sensor network is further increased. Numerical simulations are conducted for performance analysis with the proposed routing scheme.
We consider a distributed source coding system in which several observations must be encoded separately and communicated to the decoder by using limited transmission rate. We introduce a robust distributedcoding sche...
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We consider a distributed source coding system in which several observations must be encoded separately and communicated to the decoder by using limited transmission rate. We introduce a robust distributedcoding scheme which flexibly trades off between system robustness and compression efficiency. The optimality of this coding scheme is proved for various special cases.
This letter develops codes for the scenario in which users with correlated messages are to encipher and compress their mess' ages without collaboration and without the use of cryptographic keys or other secret mat...
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This letter develops codes for the scenario in which users with correlated messages are to encipher and compress their mess' ages without collaboration and without the use of cryptographic keys or other secret materials. We consider an eavesdropper that has access to an encoded message and in addition, some side-information in the form of uncoded symbols corresponding to the encoded message. Our codes are an extension of distributed source coding using syndromes (DISCUS) with the additional requirement of providing secrecy for the scenario described above. We state a secrecy condition that the subcodes of DISCUS must satisfy, and develop a general encoding algorithm meeting these conditions. We analyze the performance of the proposed code for the case of multiple eavesdropped messages.
Media authentication and tampering localization are important in content delivery via untrusted intermediaries, such as peer-to-peer (P2P) file sharing. Many differently encoded versions of a media file might exist. O...
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ISBN:
(纸本)9781424417650
Media authentication and tampering localization are important in content delivery via untrusted intermediaries, such as peer-to-peer (P2P) file sharing. Many differently encoded versions of a media file might exist. Our previous work applied distributed source coding to authenticate the legitimate diversity of encoded images and also localize the tampered regions in an inauthentic image. The authentication/localization decoder was supplied with a Slepian-Wolf encoded image projection as authentication data. We extend our scheme to localize tampering in contrast and brightness adjusted images using an Expectation Maximization algorithm at the decoder. Experimental results demonstrate that tampered image blocks can be identified with high probability using data of only a few hundred bytes for a 512x512 image.
A novel compression method for interferential multispectral images based on distributed source coding is proposed. Slepian-Wolf and Wyner-Ziv theorems on sourcecoding with side information are taken as the basic codi...
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ISBN:
(纸本)9780819473042
A novel compression method for interferential multispectral images based on distributed source coding is proposed. Slepian-Wolf and Wyner-Ziv theorems on sourcecoding with side information are taken as the basic coding principles. In our system, a rate control solution is proposed to avoid the feedback channel used in many practical distributed source coding solutions. The residual statistics between corresponding coefficients in original frame and the side information frame is assumed to be modeled by Laplacian distribution. We estimate the distribution parameter on line at the encoder at subband levels. The experimental results show that our method outperforms significantly over JPEG2000, especially at medium and low bit rates,the method can obtain about 5dB gains than JPEG2000, and the subjective quality is obviously enhanced.
This paper presents a reduced-reference image quality assessment scheme using distributed source coding for remotely monitoring image quality. In our scheme, an image server extracts a feature vector from the original...
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ISBN:
(纸本)9781424425709
This paper presents a reduced-reference image quality assessment scheme using distributed source coding for remotely monitoring image quality. In our scheme, an image server extracts a feature vector from the original image and transmits its Slepian-Wolf syndrome using an LDPC encoder. With the rate of the Slepian-Wolf bitstream chosen according to a predetermined admissible image quality, the receiver can reconstruct the feature vector using its received image, as side information, as long as the quality is higher than the admissible quality. Thus the receiver can determine the received image quality using the reconstructed feature vector. Simulation results show that distributed source coding can reduce the bit-rate of the feature vector by 50% and achieve better compression performance than conventional sourcecoding.
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