• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 405
  • 49
  • 49
  • 21
  • 19
  • 12
  • 11
  • 10
  • 9
  • 8
  • 8
  • 6
  • 5
  • 4
  • 4
  • Tagged with
  • 684
  • 343
  • 268
  • 84
  • 68
  • 68
  • 62
  • 55
  • 54
  • 54
  • 50
  • 47
  • 47
  • 46
  • 45
  • 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.
21

Inequality, early school-leavers and adult basic education

Stephey, Merle Edward. January 1900 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 164-190).
22

Educational stratification in Viet Nam during the evolution and devolution of socialism /

Nguyen, Lan Phuong. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 336-348).
23

A Comparative Study of the Equalization and the Foundation Program of Finance in the Schools of Jones County, Texas

Martin, Samuel Dean January 1950 (has links)
The problem of this study is to compare the effects of the Equalization Fund Program of 1948-1949 and the Foundation School Program of 1949-1950 upon the public schools in Jones County, Texas. The purpose of the investigation was to determine specifically the effects of the new financial plan as related to the three preceding phases of the educational program.
24

An analysis of attitudes pertaining to the equality of opportunity to play sports and sport engagement of fifth- and eighth-grade students in an inner city, urban, and suburban setting /

Mixon, Lawrence Bruce January 1981 (has links)
No description available.
25

Automatic Modulation Classication and Blind Equalization for Cognitive Radios

Ramkumar, Barathram 08 September 2011 (has links)
Cognitive Radio (CR) is an emerging wireless communications technology that addresses the inefficiency of current radio spectrum usage. CR also supports the evolution of existing wireless applications and the development of new civilian and military applications. In military and public safety applications, there is no information available about the signal present in a frequency band and hence there is a need for a CR receiver to identify the modulation format employed in the signal. The automatic modulation classifier (AMC) is an important signal processing component that helps the CR in identifying the modulation format employed in the detected signal. AMC algorithms developed so far can classify only signals from a single user present in a frequency band. In a typical CR scenario, there is a possibility that more than one user is present in a frequency band and hence it is necessary to develop an AMC that can classify signals from multiple users simultaneously. One of the main objectives of this dissertation is to develop robust multiuser AMC's for CR. It will be shown later that multiple antennas are required at the receiver for classifying multiple signals. The use of multiple antennas at the transmitter and receiver is known as a Multi Input Multi Output (MIMO) communication system. By using multiple antennas at the receiver, apart from classifying signals from multiple users, the CR can harness the advantages offered by classical MIMO communication techniques like higher data rate, reliability, and an extended coverage area. While MIMO CR will provide numerous benefits, there are some significant challenges in applying conventional MIMO theory to CR. In this dissertation, open problems in applying classical MIMO techniques to a CR scenario are addressed. A blind equalizer is another important signal processing component that a CR must possess since there are no training or pilot signals available in many applications. In a typical wireless communication environment the transmitted signals are subjected to noise and multipath fading. Multipath fading not only affects the performance of symbol detection by causing inter symbol interference (ISI) but also affects the performance of the AMC. The equalizer is a signal processing component that removes ISI from the received signal, thus improving the symbol detection performance. In a conventional wireless communication system, training or pilot sequences are usually available for designing the equalizer. When a training sequence is available, equalizer parameters are adapted by minimizing the well known cost function called mean square error (MSE). When a training sequence is not available, blind equalization algorithms adapt the parameters of the blind equalizer by minimizing cost functions that exploit the higher order statistics of the received signal. These cost functions are non convex and hence the blind equalizer has the potential to converge to a local minimum. Convergence to a local minimum not only affects symbol detection performance but also affects the performance of the AMC. Robust blind equalizers can be designed if the performance of the AMC is also considered while adapting equalizer parameters. In this dissertation we also develop Single Input Single Output (SISO) and MIMO blind equalizers where the performance of the AMC is also considered while adapting the equalizer parameters. / Ph. D.
26

Signal Enhancement in Wireless Communications Systems / Signalförbättring i trådlösa telekommunikationssytem

Nordberg, Jörgen January 2002 (has links)
Digital Wireless communications has been one of the fastest growing communication techniques during the last decade. Today there exists several different communication systems that use wireless techniques. They share one common property that they transmit data through a radio interface. The radio channel is a tough channel that will both distort and disturb the transmitted signal in various ways. In Jörgen Nordberg's PhD-thesis "Signal Enhancement in Wireless Communications Systems" several different signal enhancement schemes are presented. They have the objective to minimize the impact of the channel. The main part of this thesis presents work on interference cancellation, i.e. how to reduce the impact of other interfering signals on the channel of interest. This is achieved by utilizing the spatial domain, i.e. the receiver is using several antennas to receive the transmitted signals. By using a multitude of antennas techniques like spatial diversity, adaptive antenna arrays, signal separation and beamforming can be applied to combat the interfering signals. In the single antenna case there is often a need to do channel equalization. Since, channel equalization is an inverse filtering, it will often result in estimation of equalization filter parameters of very high order. To reduce the both the complexity and improve the convergence speed of the equalization filter parameter estimation subband processing techniques can be used. In this case the received signal is separated up into different frequency bands (subbands) and decimated according to the bandwidth of the signal. The channel equalization problem is then solved for each subband at a lower sampling rate. Hence, the channel equalization problem is transformed from estimating the parameters of a high order filter into estimating several filter of much lower order. / Ett av områdena inom telekommunikation som har ökat mest de senaste åren är radio kommunikation. Det finns många olika varianter av trådlösa radio system, men de har alla en sak gemensamt, de överför information/data via ett radiogränssnitt. Signaler som sänds över en radiokanal kommer på grund av många olika anledningar att bli störda eller distorderade. I Jörgen Nordbergs doktorsavhandling ?Signal Enhancement in Wireless Communication Systems? presenteras flera metoder för att förbättra kvaliten i de mottagna signalerna vilket ger betydande kvalitetsförbättring. Huvuddelen av denna doktorsavhandling behandlar interferensundertrycking, d.v.s. hur man undertrycker oönskad störning på den egna radiokanalen. Dessa metoder är baserade på användning av flera antenner i mottagaren. Genom att ta emot signalerna med flera antenner så kan metoder såsom diversitetskombinering, adaptiva antenner, lobformning, signal separation användas för att förbättra kvaliteten i den mottagna signalen. Om mottagaren har en antenn så behövs oftast kanalutjämning för att förbättra den mottagna signalen och undertrycka intersymbolinterferens. Eftersom kanalutjämning är en typ av inversfiltrering leder detta ofta till estimering av filterparametrar av hög ordning. Estimeringsproblem av hög ordning leder ofta till komplexitetsproblem och konvergensproblem hos estimerings algoritmen. För att motverka dessa problem så presenteras i denna avhandling en kanalutjämnare som är baserad på subbandsteknik. I denna kanalutjämnare så delas den mottagna signalen upp i flera frekvensband (subband) som decimeras till en takt som motsvarar subbandets bandbredd varefter filterparametrarna estimeras i denna lägre takt. Därvid har estimeringsproblemet delats upp i flera små problem som kan hanteras enklare.
27

Utjämningsskatten och dess effekter på investeringsutgiften : Fallet Danderyds Kommun

Ulasevich, Veronika January 2013 (has links)
For a long time economic tax equalization system in Sweden has been creating dispute between Swedish communities. Despite the main purpose of the system - to reduce disparities and create equal economic opportunities for all communities – some regions were not satisfied. The main purpose of this study is to determine what extant has equalization tax on investment spending of Danderyd municipality during 2000-2010 year period. The study is based on annual reports and personal interviews. The theoretical frame of the investigation is founded on Fjertorp's classification of investments and public choice theory. The investigation shows that there were no significant changes neither in investment spending or equalization tax during 2000-2010 period, even after the last changes of economic tax equalizations system in 2005. This study also showed that the equalization tax had no impact on investment spending in Danderyd community during 2000-2010 year period. In my opinion negative attitude towards tax equalization system occurs because of ideology and politics as whole.
28

Design and analysis of iteratively decodable codes for ISI channels

Doan, Dung Ngoc 01 November 2005 (has links)
Recent advancements in iterative processing have allowed communication systems to perform close to capacity limits withmanageable complexity.For manychannels such as the AWGN and flat fading channels, codes that perform only a fraction of a dB from the capacity have been designed in the literature. In this dissertation, we will focus on the design and analysis of near-capacity achieving codes for another important class of channels, namely inter-symbol interference (ISI)channels. We propose various coding schemes such as low-density parity-check (LDPC) codes, parallel and serial concatenations for ISI channels when there is no spectral shaping used at the transmitter. The design and analysis techniques use the idea of extrinsic information transfer (EXIT) function matching and provide insights into the performance of different codes and receiver structures. We then present a coding scheme which is the concatenation of an LDPC code with a spectral shaping block code designed to be matched to the channel??s spectrum. We will discuss how to design the shaping code and the outer LDPC code. We will show that spectral shaping matched codes can be used for the parallel concatenation to achieve near capacity performance. We will also discuss the capacity of multiple antenna ISI channels. We study the effects of transmitter and receiver diversities and noisy channel state information on channel capacity.
29

Design and analysis of iteratively decodable codes for ISI channels

Doan, Dung Ngoc 01 November 2005 (has links)
Recent advancements in iterative processing have allowed communication systems to perform close to capacity limits withmanageable complexity.For manychannels such as the AWGN and flat fading channels, codes that perform only a fraction of a dB from the capacity have been designed in the literature. In this dissertation, we will focus on the design and analysis of near-capacity achieving codes for another important class of channels, namely inter-symbol interference (ISI)channels. We propose various coding schemes such as low-density parity-check (LDPC) codes, parallel and serial concatenations for ISI channels when there is no spectral shaping used at the transmitter. The design and analysis techniques use the idea of extrinsic information transfer (EXIT) function matching and provide insights into the performance of different codes and receiver structures. We then present a coding scheme which is the concatenation of an LDPC code with a spectral shaping block code designed to be matched to the channel??s spectrum. We will discuss how to design the shaping code and the outer LDPC code. We will show that spectral shaping matched codes can be used for the parallel concatenation to achieve near capacity performance. We will also discuss the capacity of multiple antenna ISI channels. We study the effects of transmitter and receiver diversities and noisy channel state information on channel capacity.
30

Equity to adequacy a historical analysis of the litigations of Abbeville v. The State of South Carolina /

Costner, Charles Alexander. January 2009 (has links)
Thesis (Ph.D.) -- Clemson University, 2009. / Includes bibliographical references (leaves 114-118). Also available online.

Page generated in 0.1126 seconds