This paper presents prediction intervals for the multiple linear regression model after forward selection. The prediction interval is for a future value of the response variable Yf given a p×1 vector of predictors xf

Ce travail est dédié à l'analyse, la conception et l'évaluation des performances des schémas de codage de réseaux pour les systèmes des communications multi-terminaux. Nous étudions en premier lieu le protocole « compute-and-forward » dans le canal à accès multiples. Nous proposons un critère de construction de codes de réseaux efficaces pour cette stratégie basé sur la résolution d'un problème du vecteur le plus court d'un réseau de points. En addition, nous développons de nouveaux algorithmes de décodage prouvés numériquement plus performants que le décodeur existant du CF. La deuxième partie concerne l'implémentation du protocole CF dans le canal à relais bidirectionnel et le canal à sources et relais multiples. Nous développons des algorithmes de construction de schémas de codage pour le CF et évaluons théoriquement et par simulations numériques leurs performances. La dernière partie concerne le canal MIMO distribué et en particulier une nouvelle architecture de décodeurs « integer forcing » inspirés par le protocole CF. Nous proposons de nouveaux algorithmes de construction des paramètres optimaux de ces décodeurs et montrons par simulations qu'ils apportent un gain significatif par rapport aux récepteurs linéaires existants / This work is dedicated to the analysis, design and performance evaluation of physical layer network coding strategies in multiuser communication systems. The first part is devoted to study the compute-and-forward protocol in the basic multiple access channel. For this strategy, we propose an optimal solution to design efficient network codes based on solving a lattice shortest vector problem. Moreover, we derive novel bounds on the ergodic rate and the outage probability for the CF operating in fast and slow fading channels respectively. Besides, we develop novel decoding algorithms proved numerically to outperform the traditional decoding scheme for the CF. The second part is dedicated to the design and end-to-end performance evaluation of network codes for the CF and the analog network coding in the two-way relay channel and the multi-source multi-relay channel. For each network model we study the decoding at the relay nodes and the end destination, propose search algorithms for optimal network codes for the CF and evaluate, theoretically and numerically, the end-to-end error rate and achievable transmission rate. In the last part, we study new decoders for the distributed MIMO channel termed integer forcing (if). Inspired by the CF, if receivers take advantage of the interference provided by the wireless medium to decode integer linear combinations of the original codewords. We develop in our work efficient algorithms to select optimal if receivers parameters allowing to outperform existing suboptimal linear receivers

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The Internet and web service have become the most popularly platform and application of the Client-Server model due to the universality of the network recently years. Its growth is too fast to imagine the effect, many traditional service changes into web service stage by stage, and the load of the servers become more and more heavy. In the situation the server architecture must be adapted oppositely. The web cluster architecture has the best suit of the scalability, reliability and high performance requirement, was used extensively. We have designed and implemented a mechanism termed Content-aware Distributor, which is a software module for kernel-level extension, to effectively support content-based routing. This paper is based on the achievement of the software-based Content-aware Distributor; we deliver some high repetition and fixity tasks to the hardware module, instead of the software module, to expect the hardware module could share the load of the software module and speedup the packet processing. We design and implement the hardware-based packet forwarding mechanism, by the analyze result from the software module; partition three major functions into three Engines: The Analyze Engine, which is responsible to identify and analyze the header of the packet, and decide the packet needs to be send to the upper layer or forwarded; The Lookup Engine, which is responsible to lookup the address of the table which stores the data of packet modification; and the Update Engine, used to modify the packet header as soon as possible then transfer to the send queue. We use an algorithm termed Patch to fast calculate the checksums; it causes the packet length independence modification. For the implementation, we use the Verilog HDL and EDA tools of Altera Corporation to accomplish the whole design. Simulation and evaluation the performance of processing the minimum packets, by operation at 50MHz system clock; our mechanism is faster double times than the packet receiving of two Fast Ethernet ports. From the resule we know our hardware mechanism is not only sharing the load of the upper layer, but also speedup the packet forwarding.

Underwater stationary targets are objects under the water that can¡¦t move autonomously. Apparatus feasible for detecting underwater stationary targets includes: optics, acoustics and geophysical instruments. The objective of this study was to investigate engineering characteristics of the battleship reef and other reefs deployed off Hai-Kou, Ping-Dong County, by the application of an integrated underwater surveying system. A total of four surveys were conducted. i.e., the 14th of April 2004, the 20th of July 2006, the 3rd of Mar. 2007 and the 30th of Oct. 2007. The investigation were completed using primarily the sidescan soner, along with other auxiliaries such as magnetometer and single beam echo sounder. Based on a mutual consideration of the results of the first survey in April 2004, the battleship on the seafloor was identified as Jong-Rong battleship. The battleship was sitting on the seabed in an upright condition at depths of 32 to 42m below the sea surface. A chain cable was catenated from the stern of the battleship down to the seabed. In addition, a large number of cubic artificial reefs were spreaded around. A comparision of results obtained during the first and the third survey indicated that the battleship was undergone a displacement of 250m. The significant displacement of the battleship was correlated with a medium magnitude typhoon passed by on the 3rd of Dec. 2004 and the 17th of May 2006 (i.e., Nanmadol and Chanchu Typhoon). The second and the third survey indicated that the battleship was¡¦t moved by earthquake on the 26th of Dec. 2006 (i.e., Herng Chuen earthquake)with magnitude of seven. A comparison of the third and the fourth surveys suggested that the battleship¡¦s bow was moved to the north for an extra 20m. This movement is correlated with a typhoon passed by in Aug. 2007(i.e., Pabuk Typhoon). However, a detailed investigation of the sonographs indicated that there are very limited relative displacement between the battleship and cement artificial reefs that scattered around the battleship. Therefore, further investigations are needed to verify this tautative conclusion. Based on sidescan soner imagery collected in four surveys between 2004 and 2007. the location of various type of artifical reefs at Hai-Kou artifical reef site were investigated. Except the battleship reef, all the orther types of reefs which include steel reef, electric-pole reef and cement reef were not displaced by either typhoon or earthquake. Under the influence of typhoon waves, the battleship reef was displaced for a distance of 250m.

A circuit design of baseband transceiver for direct sequence ultra-wide band system is presented in this thesis. A low complexity Viterbi decoder is also proposed. This Viterbi decoder circuit is based on compare-select-add unit and trace-forward architecture. The decision bit operator is reduced to one adder and this can lower down the hardware complexity. Further, two trace-forward operators are used in the survivor management unit. Only two single port SRAM¡¦s with a length of T are applied for reducing the area of memory. The chip is implemented by TSMC standard 0.18-£gm 1P6M CMOS process with core area 1.061 ¡Ñ 1.069 mm2. The post-layout simulation with 1.8V supply at 25 shows that the proposed direct sequence ultra-wide band system of baseband transceiver chip can work above 141 MHz with 86.41 mW power dissipation.

Induction logging is a well-developed geophysical method with multiple applications. It has been used extensively in academic research as well as in industry. Induction logging is a controlled-source electromagnetic (CSEM) exploration method. It characterizes geologic formations through the measurements of induced magnetics fields. The purpose of this research project is to better understand induction logs and the effects fractured geologic formations have on them. Computer modeling is used to generate synthetic logs for analysis in this research project. The original program required certain modifications to fit this research project’s goals. The computer program, Seatem is based on the finite element method. It is able to use a layered Earth model that is the basis for the synthetic log analysis. The geologic layers in this model are assigned various conductivities and also have the option of being assigned a geologic roughness value. The geologic roughness parameter is used to simulate fractured rocks in the subsurface. The synthetic logs generated by the modified Seatem program produce some encouraging results. In a thinning bed analysis, it is shown that as a conductive bed is thinned in a step-size procedure, the resulting induction log underestimates the actual conductivity of the layer. It also shows that the boundary layers around the thinned layer are better characterized in the log. The next synthetic log was calculated for a fractured resistive layer. This log shows that as the layer becomes more fractured, there is an increase in the underestimation of the actual conductivity. This layer is then thinned down and another synthetic log is calculated. The resulting log shows similar traits to the thinning bed analysis and shows an underestimation of the apparent conductivity. The same procedure is performed for a fractured conductive layer. The analysis produce similar results; however, that are much more drastic changes in the induction logs. As the unit becomes more fractured, the apparent conductivity is lower then the actual conductivity, as in the resistive case. However, smaller increases in the roughness parameter produced more severe underestimations than larger increases in the roughness parameter did for the resistive layer.

Zugl.: Leipzig, Univ., Diplomarbeit, 2006