Network Coding: Connections Between Information Theory And Estimation Theory

In this paper, we prove the existence of fundamental relations between information theory and estimation theory for network-coded flows. When the network is represented by a directed graph G=(V, E) and under the assumption of uncorrelated noise over information flows between the directed links connecting transmitters, switches (relays), and receivers. We unveil that there yet exist closed-form relations for the gradient of the mutual information with respect to different components of the system matrix M. On the one hand, this result opens a new class of problems casting further insights into effects of the network topology, topological changes when nodes are mobile, and the impact of errors and delays in certain links into the network capacity which can be further studied in scenarios where one source multi-sinks multicasts and multi-source multicast where the invertibility and the rank of matrix M plays a significant role in the decoding process and therefore, on the network capacity. On the other hand, it opens further research questions of finding precoding solutions adapted to the network level.Comment: IEEE Wireless Communications and Networking Conference (WCNC), April, 201

Piggybacking Codes for Network Coding: The High/Low SNR Regime

We propose a piggybacking scheme for network coding where strong source inputs piggyback the weaker ones, a scheme necessary and sufficient to achieve the cut-set upper bound at high/low-snr regime, a new asymptotically optimal operational regime for the multihop Amplify and Forward (AF) networks

Izin Isteri dalam Poligami Perspektif Undang Undang Nomor 1 Tahun 1974 Tentang Perkawinan

Pernikahan adalah suatu hubungan cinta , kasih sayang dan kesenangan , pernikahan sebagai sarana untuk menciptakan kasih sayang, serta perisai untuk suami dan istri dari bahaya kekejian. Dalam buku al-Hikmah konstitusi, wa Falsafatuh , Sheikh Ali Ahmad al - Jurjawi menjelaskan Imam Syafii pendapat bahwa laki-laki poligami harus benar-benar, tanpa persetujuan dari istri. Poligami harus dilakukan selama jika jumlah istri tidak lebih empat. Sementara itu, menurut Hanafi poligami dapat dilakukan tanpa izin dari istri, tapi diperlukan untuk melakukan keadilan diberkaitan dengan kepuasan psikis, seperti seks. Hukum yang berlaku di Indonesia suami yang akan menikhan diminta untuk mendapatkan izin poligami dari istri, sedangkan istri dalam hukum Islam bukan persyaratan dalam menahan poligam

Study On Barringtonia Asiatica Kurz

Telah dilakukan suatu penelitian tentang Barringtonia asiatica Kurz. Dua senyawa sapogenin telah dapat dipisahkan dari benih Barringtonia asiatica Kurz. Titik lebur mereka adalah 243-245°C untuk senyawa R1 dan 266-268°C untuk senyawa R2 . Spektrum IR menunjukkan bahwa senyawa R2 memiliki functional groups yang terdiri atas OH, CH, C = C, C -O -C dan CH3 sedangkan senyawa R1 me­miliki functional groups OH, C-H, C = C dan C-O-C dalam strukturnya

Reliability of Trigonometric Transform-based Multi-Carrier Scheme

This work is looking for a new physical layer of a multi-carrier wireless communication system to be implemented in low complexity way, resorting to suitable fast transform. The work presents and assesses a scheme based on Discrete Trigonometric Transform with appending symmetric redundancy either in each or multiple consecutive transformed blocks. A receiver front-end filter is proposed to enforce whole symmetry in the channel impulse response, and bank of one tap filter per sub-carrier is applied as an equalizer in the transform domain. The behaviour of the transceiver is studied in the context of practical impairments like fading channel, carrier frequency offset and narrow band interference. Moreover, the performance is evaluated in contrast with the state of art methods by means of computer simulations, and it has been found that the new scheme improves robustness and reliability of communication signal, and record lower peak to average power ratio. The study demonstrates that front-end matched filter effectively performs frequency synchronization to compensate the carrier frequency offset in the received signal

A Family of Hierarchical Encoding Techniques for Image and Video Communications

As the demand for image and video transmission and interactive multimedia applications continues to grow, scalable image and video compression that has robust behavior over unreliable channels are of increasing interest. These desktop applications require scalability as a main feature due to its heterogeneous nature, since participants in an interactive multimedia application have different needs and processing power. Also, the encoding and decoding algorithm complexity must be low due to the practical considerations of low-cost low-power receiver terminals. This requires image and video encoding techniques that jointly considers compression, scalability, robustness, and simplicity. In this dissertation, we present a family of image and video-encoding techniques, which are developed to support conferencing applications. We achieve scalability, robustness and low computational complexity by building our encoding techniques based on the quadtree and octree representation methods. First we developed an image encoding technique using the quadtree representation of images and vector quantization. We use a mean-removal technique to separate the means image and the difference image. The difference image is then encoded as a breadth first traversal of the quadtree corresponding to the image. Vector quantization is then used to compress the quadtree nodes based on the spatial locality of the quadtree data. Our next step was to use the quadtree-based image encoding technique as a base for developing a differential video encoding technique. We extended it to encode video by applying the well-known IPB technique to the image encoding system. Then, we explore another method of extending our image encoding technique to encode video streams. The basic idea was to use exactly the same three steps used in our image encoding technique, mean removal, conversion to tree structure, and vector quantization, and replace the quadtree structure with an octree structure. The octree is the three-dimensional equivalent of the quadtree. We divide the sequence of frames into groups and view each group as a three-dimensional object. By encoding frames together, we can obtain substantial savings in encoding time and better compression results. Finally, we combined both the differential quadtree and octree approaches to generate a new hybrid encoding technique. We encode one frame using the quadtree-based image encoding technique, and then encode the following group of frames as a differential octree based upon the first frame. Using a set of experiments, the quadtree-based image encoding and differential video encoding techniques were shown to provide reasonable compression in comparison with similar techniques, while the octree and hybrid video encoding techniques gave impressive compression results. Furthermore, we demonstrated that our encoding techniques are time efficient compared to the more common frequency based techniques. We also compare their scalability feature favorably with other well-known scalable techniques. Moreover, we demonstrated their ability to tolerate and conceal error. The new encoding techniques proved to be efficient methods of encoding for interactive multimedia applications