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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Coded modulation techniques with bit interleaving and iterative processing for impulsive noise channels

Bui, Trung Quang 22 August 2006 (has links)
Power line communications (PLC) surfers performance degradation due mainly to impulsive noise interference generated by electrical appliances. This thesis studies coded modulation techniques to improve the spectral efficiency and error performance of PLC. Considered in the first part is the application of bit-interleaved coded modulation with iterative decoding (BICM-ID) in class-A impulsive noise environment. In particular, the optimal soft-output demodulator and its suboptimal version are presented for an additive class-A noise (AWAN) channel so that iterative demodulation and decoding can be performed at the receiver. The effect of signal mapping on the error performance of BICM-ID systems in impulsive noise is then investigated, with both computer simulations and a tight error bound on the asymptotic performance. Extrinsic information transfer (EXIT) chart analysis is performed to illustrate the convergence properties of different mappings. The superior performance of BICMID compared to orthogonal frequency-division multiplexing (OFDM) is also clearly demonstrated.<p>Motivated by the successes of both BICM-ID and OFDM in improving the error performance of communications systems in impulsive noise environment, the second part of this thesis introduces a novel scheme of bit-interleaved coded OFDM with iterative decoding (BI-COFDM-ID) over the class-A impulsive noise channel. Here, an iterative receiver composed of outer and inner iteration loops is first described in detail. Error performance improvements of the proposed iterative receiver with different iteration strategies are presented and discussed. Performance comparisons of BI-COFDM-ID, BICM-ID and iteratively decoded OFDM are made to illustrate the superiority of BI-COFDM-ID. The effect of signal mapping on the error performance of BI-COFDM-ID is also studied.
92

Understanding reading comprehension : multiple and focused strategy interventions for struggling adolescent readers

Yee, Nikki L. 13 April 2010 (has links)
The purpose of this study was to investigate methods for improving reading comprehension among struggling adolescent readers. More specifically, this study was concerned with: the effectiveness of pull-out intervention for reading outcomes in this population; the most effective type of intervention; and the contributions of instructional method to reading comprehension after decoding has been removed. These questions were answered with the help of 29 students from a rural school division in Saskatchewan who volunteered to participate in testing and various forms of reading intervention for a period of four to five weeks. Students were placed into one of three groups: the MSI group practiced decoding and learned six comprehension strategies; the FSI group practiced decoding and learned just two comprehension strategies; and the control group who participated in their typical education program. In sum, the analysis produced the following results:<p> 1.Pull-out intervention (pre-test M = 6.00; post-test M = 7.33) did not offer a statistically significant advantage over the typical classroom setting (pre-test M = 7.00; post-test M = 7.05) when attempting to remediate reading comprehension;<p> 2.Participants in the MSI group demonstrated significant improvement on measures of decoding (p = .001; ©¯p2 = .75);<p> 3.Although statistical testing did not reveal significant results, effect sizes were large for: participants in the MSI group on measures of fluency (©¯p2 = .39); participants in the FSI group on measures of fluency (©¯p2 = .53) and the Oral Reading Quotient (©¯p2 = .37); participants in the control group on measures of decoding (©¯p2 = .21), comprehension (©¯p2 = .38), fluency (©¯p2 = .32), and the Oral Reading Quotient (©¯p2 = .50); and<p> 4.Decoding accounted for a statistically significant 15.4% of the unique variance in post-test comprehension scores (p = .03), but differences in grouping contributed a negligible amount (p = .1; R2 change = .004).
93

Fokus på mottagarna? : En analys av Krisberedskapsmyndighetens forskningsrapporter vid kriskommunikation

Gunningberg, Sara January 2007 (has links)
SAMMANFATTNING Denna studie är en analys av Krisberedskapsmyndighetens forskningsrapporter ifråga om deras perspektiv på mottagarna vid kriskommunikation. Studien har två syften, dels att undersöka vilken roll forskarna ger mottagarna i de nuvarande studierna, dels att reflektera hur forskningen skulle kunna kompletteras i framtiden. Krisberedskapsmyndigheten är den myndighet som ansvarar för att vara samordnande myndighet i en krissituation, planera inför kommande kriser och att samla in kunskap om kriser. Denna studie använder sig av mottagarperspektivet encoding/decoding för att undersöka Krisberedskapsmyndighetens forskningsrapporter. Encoding/decoding perspektivet ser på mottagarna som aktiva och komplexa i tolkningen av meddelanden. Perspektivet menar att olika mottagare kan tolka information på olika sätt beroende på vilken bakgrund mottagaren har. Jag har även tagit upp grundbegreppen för kriskommunikation, vad samhällsvetenskaplig forskning innebär och kriterier för Krisberedskapsmyndighetens forskningsfinansiering för att få en ökad förståelse för rapporterna. För att komma fram till studiens resultat har jag använt mig av metoden sekundäranalys och har valt ut sju rapporter från Krisberedskapsmyndigheten och Styrelsen för psykologiskt försvar. Studiens resultat visar att flera av forskningsrapporterna förenklar mottagarnas roll då kriskommunikation undersöks. Detta får konsekvensen att flera av rapporterna är sändarinriktade. Jag har reflekterat i hur Krisberedskapsmyndigheten kan utveckla forskningen kring kriskommunikation och mottagarna, och det handlar främst om att göra fler mottagarstudier och att ge mottagarna en mer komplex roll. Min studie visar på att det finns fyra forskningsområden som kan undersökas ytterligare; mottagarnas tolkning av sändarens kommunikation, mottagarnas kommunikation med varandra, mottagarnas kommunikation med myndigheter och medier och medierna som något mer än en informationskanal. Genom denna studie har jag visat på att det finns outforskade områden som är relevanta för kriskommunikationen. Jag ifrågasätter främst Krisberedskapsmyndigheten för frånvaron av dessa outforskade områden. Uppdraget hos myndigheten är mycket sändarinriktad och jag reflekterar omkring att det kan vara en orsak till att de flesta av forskningsrapporterna har inriktning på sändarna. Jag antyder att Krisberedskapsmyndighetens rapporter har drag av processkolan som ser på kommunikation som en styrd överföring av budskap från sändare till mottagare. Fokus i rapporterna ligger nämligen någon annanstans än på mottagarna och deras komplexitet vilket jag ser som ett problem.
94

A Low-power Convolutional Decoder with Error Detection Ability

Yeh, Wei-ting 03 August 2010 (has links)
In wireless communication systems, we may encounter many problems. One of the main issues is noise interference. To overcome the problem, the sender can use the Convolutional coding method to encode the data, and the receiver can utilize the Viterbi algorithm for decoding and correction purposes. Due to the high complexity of the Viterbi algorithm, the VLSI structure of Viterbi decoder will consume large amounts of power, leading the portable devices to short standby time and high operating temperature. In order to solve these problems we have to design a low power decoder. As a matter of fact, the Viterbi decoder can be actually shutdown when no noise interference exists. As a consequence, we use a detection circuit to determine whether the signal is influenced by noise. If the signal is interfered, we choose the Viterbi decoder to perform the decoding process. Otherwise, we utilize a low cost decoder to lessen the power consumed at the receiver end. In addition, dynamic adjustment of SMU module is also developed and implemented in the proposed decoder. SMU module consumes the most power in Viterbi decoder. So, our developed and goal is to reduce the usage of SMU module. If noise distribution is not so dense, we don¡¦t have to use high decoding ability to decode section data. Therefore, the registers in SMU can be decreased. Clock gating technique is adopted in this thesis to shutdown these idle registers to reduce the power consumption of SMU. The proposed decoder has been implemented and synthesized using the Artisan TSMC 0.13£gm standard cell library. Compared with the traditional Viterbi decoder, the proposed decoder can achieve 25% and nearly 60% power saving when the SNR is 1dB and 8dB respectively, with 6% area reduction. According to the above experimental results, we can say that the proposed decoder is able to reduce power consumption.
95

Variable length pattern coding for power reduction in off-chip data buses

Venkitasubramanian Iyer, Jayakrishnan 15 May 2009 (has links)
Off-chip buses consume a huge fraction (20%-40%) of the system power. Hence, techniques such as increasing bus widths, transition encoding etc. have been used for power reduction on off-chip data buses. Since capacitances at the I/O pads and interwire capacitances contribute significantly to increase in power, encoding/decoding schemes have been developed to reduce switching activity of the off-chip bus lines, thus reducing power. Frequent-Value Encoding(FVE) [1], Frequent Value Encoding with Xor (FVExor) [1] and VALVE [2] are some of the better known encoding schemes but they still have scope for improvement. This thesis addresses the problem of power reduction in off-chip data buses by encoding variable number (1 to 4) of fixed-size (32-bit) data values (variable length patterns) which exhibit temporal locality. This characteristic enables us to cache these patterns using 64-entry CAM at the encoder and 64-entry SRAM at the decoder. Whenever a pattern match occurs a 2-bit code indicating the index of the match is sent. If a variable length pattern match occurs then the code and unmatched portion of data is sent. We implemented our scheme, Variable Length Pattern Coding (VLPC) for various integer and floating point benchmarks and have seen 6% to 49% encodable patterns in these benchmarks. Based on the experiments on simplescalar and our analysis in MATLAB, we obtained 4.88% to 40.11% reduction in transition activity for SPEC2000 benchmarks such as crafty, swim, mcf, applu, ammp etc. over unencoded data. This is 0.3% to 38.9% higher than that obtained using FVE, FVExor [1] and VALVE [2] encoding schemes. Finally, we have designed a low-power custom CAM and SRAM using 45nm BSIM4 technology models which has been used to verify lower latency of data matching and storing.
96

MP3 Decoding Software Implementation for a DSP-enhanced Microcontroller

Chen, Shi-Wei 09 January 2004 (has links)
Multimedia workloads have always held an important role in embedded applications. Products are multifarious, such as various modeling mobile phone, MP3 player which is deft and convenient to carry and PDA which is popular with workers. We touch them all the time in our life. So these kinds of products are usually not high price. If their design cost and production cost are lower than others, then they can earn profits in this competition market. In so much multimedia applications, the most popular MP3 is our research goal. The design methods of multimedia audio application are using high performance CPU or combining general purpose processor with a DSP. Their performance satisfied the demand of multimedia application really, but the system hardware cost will increase at the same time. It is not the best solution in embedded products which emphasizing that low cost is better than high performance. So, my thesis will focus on MP3 algorithm optimization. We analyzed MP3 decoder algorithms, and found out the key operation. Using the SIMD operation feature of low cost multimedia processor development from our lab (It¡¦s named ME-MCU) to accelerate the processor speed. Then, I don¡¦t need a strong CPU or DSP, and I also can complete the MP3 decode operations as well. When I optimized the MP3 algorithm, I hope to provide some suggestion for ME-MCU modification. And the multimedia application will more agree with ME-MCU.
97

A New Viterbi Algorithm with Adaptive Path Reduction Method

Yamazato, Takaya, Sasase, Iwao, Mori, Shinsaku 09 1900 (has links)
No description available.
98

Decoding of the Gendered Implications in Love Songs

Tai, Wei-Ting 10 September 2008 (has links)
Love has been one of the most important issues in human life for all time. It means strong emotional and physical connections and lets people indulge themselves in its joy, depression, anticipation, and striving. Among popular music nowadays, there are always descriptions about love in most of songs, which called ¡§Love Songs¡¨. The goal of this study is to observe how the users interpret the gendered implications in love songs when they are listening to them. Furthermore, this study tries to find out the relation between users¡¦ interpretations of love songs and their love experiences and imaginations. Adopting the method of in-depth interviewing, this study interviewed 11 college students and collected related information. Through analyzing the interpretation toward specific love song lyrics of these interviewees and their explanations about their own love experiences and imaginations, this study finds that users will think about the gendered implications in the specific love song lyrics they chose when they are engaging in love song decoding. At the same time, they show their understanding toward the mainstream gender discourse. With the comparisons between users¡¦ decoding and mainstream gender discourse, this study categorizes the decoding of love songs of users into three positions: preferred, negotiated, and oppositional/ critical. Meanwhile, users will connect their love experiences and imagination about love relationship to the characters and plots in love songs, expressing their attitudes to the characters, including of identification, denial, projection, and question. Besides, study finds that there is a two-way interactive relationship between users; love songs decoding and their love experiences and imaginations. That is, not only users¡¦ love experiences and imaginations would influence their interpretations of love songs, users¡¦ interpretations of love songs would also influence their imaginations and anticipations toward love
99

Fokus på mottagarna? : En analys av Krisberedskapsmyndighetens forskningsrapporter vid kriskommunikation

Gunningberg, Sara January 2007 (has links)
<p>SAMMANFATTNING</p><p>Denna studie är en analys av Krisberedskapsmyndighetens forskningsrapporter ifråga om deras perspektiv på mottagarna vid kriskommunikation. Studien har två syften, dels att undersöka vilken roll forskarna ger mottagarna i de nuvarande studierna, dels att reflektera hur forskningen skulle kunna kompletteras i framtiden. Krisberedskapsmyndigheten är den myndighet som ansvarar för att vara samordnande myndighet i en krissituation, planera inför kommande kriser och att samla in kunskap om kriser.</p><p>Denna studie använder sig av mottagarperspektivet encoding/decoding för att undersöka Krisberedskapsmyndighetens forskningsrapporter. Encoding/decoding perspektivet ser på mottagarna som aktiva och komplexa i tolkningen av meddelanden. Perspektivet menar att</p><p>olika mottagare kan tolka information på olika sätt beroende på vilken bakgrund mottagaren har. Jag har även tagit upp grundbegreppen för kriskommunikation, vad samhällsvetenskaplig forskning innebär och kriterier för Krisberedskapsmyndighetens forskningsfinansiering för att få en ökad förståelse för rapporterna. För att komma fram till studiens resultat har jag använt mig av metoden sekundäranalys och har valt ut sju rapporter från Krisberedskapsmyndigheten och Styrelsen för psykologiskt försvar.</p><p>Studiens resultat visar att flera av forskningsrapporterna förenklar mottagarnas roll då kriskommunikation undersöks. Detta får konsekvensen att flera av rapporterna är sändarinriktade. Jag har reflekterat i hur Krisberedskapsmyndigheten kan utveckla forskningen kring kriskommunikation och mottagarna, och det handlar främst om att göra fler mottagarstudier och att ge mottagarna en mer komplex roll. Min studie visar på att det finns fyra forskningsområden som kan undersökas ytterligare; mottagarnas tolkning av sändarens kommunikation, mottagarnas kommunikation med varandra, mottagarnas kommunikation med myndigheter och medier och medierna som något mer än en informationskanal.</p><p>Genom denna studie har jag visat på att det finns outforskade områden som är relevanta för kriskommunikationen. Jag ifrågasätter främst Krisberedskapsmyndigheten för frånvaron av dessa outforskade områden.</p><p>Uppdraget hos myndigheten är mycket sändarinriktad och jag reflekterar omkring att det kan vara en orsak till att de flesta av forskningsrapporterna har inriktning på sändarna. Jag antyder att Krisberedskapsmyndighetens rapporter har drag av processkolan som ser på kommunikation som en styrd överföring av budskap från sändare till mottagare. Fokus i rapporterna ligger nämligen någon annanstans än på mottagarna och deras komplexitet vilket jag ser som ett problem.</p>
100

Pulse Position Modulation using BICM-ID for FSO Channels

Kumar, Kuldeep 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / We investigate pulse position modulation (PPM) and multipulse PPM (MPPM) for free space op- tical channels using bit interleaved coded modulation with iterative decoding. Data bits are first encoded by using a non recursive convolutional code and the coded bits after an interleaver are modulated before transmission. Iterative decoding is performed at the receiver. Optimized mapping is designed for MPPM. A genetic algorithm is used to find the optimized mapping for MPPM. Our simulation results show that a significant improvement in the error performance can be achieved by using optimized mapping and iterative decoding at the receiver.

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