http://hdl.handle.net/10125/2048 Sat, 25 May 2013 12:56:41 GMT 2013-05-25T12:56:41Z http://hdl.handle.net/10125/20577 Thesis (Ph.D.)--University of Hawaii at Manoa, 2008.; Doubly GLDPC (DGLDPC) codes are proposed to compensate the rate loss of GLDPC codes. EXIT charts are used to analyze DGLDPC codes and EXIT functions for variable component codes are thoroughly discussed. Based on EXIT charts, differential evolution is used to optimize their threshold. Ensemble weight enumerators are generalized to protograph-based DGLDPC codes. Simulation results show that DGLDPC codes constructed based on these results can improve the performance of their LDPC and GLDPC counterparts in both the waterfall region and the error floor region.; Low-density parity-check (LDPC) codes have received significant attention due to their near-Shannon-limit error performance. The belief propagation (BP) algorithm is the best-known decoding algorithm for LDPC codes. However it often needs several tens or hundreds of iterations to converge. Although fast convergence BP algorithms have been proposed, there is neither an easy tool to analyze their performance nor a standard VLSI architecture to implement them. Moreover, there exists a trade-off between waterfall (i.e., threshold) and error floor (i.e., minimum pseudo distance) performances for LDPC codes. For generalized LDPC (GLDPC) codes, better minimum distance properties can be achieved, but at the expense of a rate loss.; This research investigates performance analysis and hardware implementation of LDPC codes using fast convergence algorithms. Closed-form extrinsic mutual information transfer (EXIT) functions for several fast convergence BP decoding algorithms are proposed. It is shown theoretically that these algorithms converge faster than standard BP, while the corresponding thresholds remain unchanged. Since these algorithms are of serial nature, their parallelization without compromising convergence speed and error performance is also investigated. This result is useful in hardware implementation because in practice partly parallel decoding schemes are often used. This result also sheds some light on how to group nodes in order to preserve performance. The VLSI architecture of a particular decoding algorithm for LDPC codes is proposed. This approach can be adopted in many standards to achieve a large throughput.; Includes bibliographical references (leaves 118-127).; Also available by subscription via World Wide Web; 127 leaves, bound 29 cm Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10125/20577 2008-01-01T00:00:00Z Wang, Yige http://hdl.handle.net/10125/20540 Thesis (Ph.D.)--University of Hawaii at Manoa, 2008.; Many low-profile, broadband antennas that operate in the relatively low frequency ranges desired for certain mobile RADAR and electronic warfare (EW) applications radiate bi-directionally. Thus, a low-profile, ultrawideband ground plane is clearly necessary to back these antennas and provide for enhanced performance. To achieve the desired performance with minimal limitations, it is logical to lean towards a hybrid design that implements a combination of ground plane options. With a hybrid approach ultrawideband operation can be achieved in a low-profile package.; This dissertation presents the design and analysis of a low-profile, ultrawideband hybrid EBG/ferrite structure. The hybrid structure consists of an EBG structure implemented with a slab of ferrite absorber resting on the backing of the structure. Reflectivity and phase simulation analyses indicate that the hybrid structure offers ultrawideband operation beginning in the hundreds of megahertz, achieving an operational bandwidth exceeding 40:1 starting at 120 MHz. Simulation analyses of the hybrid structure implemented with Raytheon's ultrawideband long slot array antenna further validate the performance of the hybrid structure. An equivalent circuit model of the hybrid structure was developed to provide a more in-depth understanding of the operation of the structure in regards to its dimensions and material properties. It is shown that unlike the circuit models for traditional EBG structures, the circuit model developed for the hybrid structure contains a resistance representing the permeability losses due to the ferrite. Additionally, it is shown that the inductive and resistive circuit components are frequency dependent and depend on the frequency dependent characteristics of the ferrite. A transverse electromagnetic (TEM) cell was designed and fabricated to experimentally analyze the performance of the hybrid structure. Presented experimental results of the reflectivity and phase analyses show good correlation with the simulated results. Experimental analyses of the surface-wave suppression capabilities of the hybrid structure indicate suppression of at least 20dB across the band and suppression exceeding 60dB in the "EBG structure" region of operation compared to an electric conductor. Thus, the implementation of the hybrid EBG/ferrite structure as a ground plane will allow for the practical and effective implementation of new ultrawideband antenna systems.; Includes bibliographical references (leaves 128-130).; Also available by subscription via World Wide Web; 130 leaves, bound 29 cm Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10125/20540 2008-01-01T00:00:00Z Bell, Jodie M http://hdl.handle.net/10125/11581 Typescript.; Thesis (Ph. D.)--University of Hawaii at Manoa, 1976.; Bibliography: leaves 132-133.; Microfiche.; xi, 133 leaves ill Thu, 01 Jan 1976 00:00:00 GMT http://hdl.handle.net/10125/11581 1976-01-01T00:00:00Z Minai, Viqar Ahmed http://hdl.handle.net/10125/11580 Typescript.; Thesis (Ph. D.)--University of Hawaii at Manoa, 1975.; Bibliography: leaves 226-230.; x, 230 leaves ill Wed, 01 Jan 1975 00:00:00 GMT http://hdl.handle.net/10125/11580 1975-01-01T00:00:00Z Jain, Nirmal http://hdl.handle.net/10125/11579 Typescript.; Thesis (Ph. D.)--University of Hawaii at Manoa, 1974.; Bibliography: leaves [112]-114.; iv, 114 leaves Tue, 01 Jan 1974 00:00:00 GMT http://hdl.handle.net/10125/11579 1974-01-01T00:00:00Z Yiu, Kai-Ping http://hdl.handle.net/10125/11578 Typescript.; Thesis (Ph. D.)--University of Hawaii at Manoa, 1974.; Bibliography: leaves 310-320.; xvi, 320 leaves ill Tue, 01 Jan 1974 00:00:00 GMT http://hdl.handle.net/10125/11578 1974-01-01T00:00:00Z Low, Nam Chong http://hdl.handle.net/10125/11577 Typescript.; Thesis (Ph. D.)--University of Hawaii,1970.; Bibliography: leaves [167]-169.; ix, 169 l illus., tables Thu, 01 Jan 1970 00:00:00 GMT http://hdl.handle.net/10125/11577 1970-01-01T00:00:00Z Kulikowski, Casimir Alexander http://hdl.handle.net/10125/11576 Thesis (Ph. D.)--University of Hawaii at Manoa, 2005.; Includes bibliographical references (leaves 125-129).; Also available by subscription via World Wide Web; xi, 129 leaves, bound ill. 29 cm Sat, 01 Jan 2005 00:00:00 GMT http://hdl.handle.net/10125/11576 2005-01-01T00:00:00Z Feng, Mu, 1974 http://hdl.handle.net/10125/11575 Thesis (Ph. D.)--University of Hawaii at Manoa, 2005.; Includes bibliographical references (leaves 105-109).; Also available by subscription via World Wide Web; xii, 109 leaves, bound ill., charts 29 cm Sat, 01 Jan 2005 00:00:00 GMT http://hdl.handle.net/10125/11575 2005-01-01T00:00:00Z Bahng, Seungjae http://hdl.handle.net/10125/11574 Thesis (Ph. D.)--University of Hawaii at Manoa, 2005.; Includes bibliographical references (leaves 84-89).; Also available by subscription via World Wide Web; xi, 89 leaves, bound ill. 29 cm Sat, 01 Jan 2005 00:00:00 GMT http://hdl.handle.net/10125/11574 2005-01-01T00:00:00Z Liu, Jianhan, 1974 http://hdl.handle.net/10125/11573 Thesis (Ph. D.)--University of Hawaii at Manoa, 2004.; Includes bibliographical references (leaves 118-126).; Also available by subscription via World Wide Web; x, 126 leaves, bound ill. 29 cm Thu, 01 Jan 2004 00:00:00 GMT http://hdl.handle.net/10125/11573 2004-01-01T00:00:00Z Talarico, Claudio http://hdl.handle.net/10125/9755 Thesis (Ph. D.)--University of Hawaii at Manoa, 1995.; Includes bibliographical references (leaves 220-227).; Microfiche.; xiii, 227 leaves, bound ill. (some col.) 29 cm Sun, 01 Jan 1995 00:00:00 GMT http://hdl.handle.net/10125/9755 1995-01-01T00:00:00Z Khan, Muhammad Javed Iqbal http://hdl.handle.net/10125/9754 Thesis (Ph. D.)--University of Hawaii at Manoa, 1995.; Includes bibliographical references (leaves 292-303).; Microfiche.; xxxii, 303 leaves, bound ill. 29 cm Sun, 01 Jan 1995 00:00:00 GMT http://hdl.handle.net/10125/9754 1995-01-01T00:00:00Z Rhee, DoJun http://hdl.handle.net/10125/9753 Thesis (Ph. D.)--University of Hawaii at Manoa, 1994.; Includes bibliographical references (leaves 199-209).; Microfiche.; xii, 209 leaves, bound ill. 29 cm Sat, 01 Jan 1994 00:00:00 GMT http://hdl.handle.net/10125/9753 1994-01-01T00:00:00Z Liu, Hui http://hdl.handle.net/10125/9752 Thesis (Ph. D.)--University of Hawaii at Manoa, 1994.; Includes bibliographical references (leaves 593-597).; Microfiche.; 2 v. (xliii, 597 leaves), bound ill. 29 cm Sat, 01 Jan 1994 00:00:00 GMT http://hdl.handle.net/10125/9752 1994-01-01T00:00:00Z Jiang, Fenglai http://hdl.handle.net/10125/9751 Thesis (Ph. D.)--University of Hawaii at Manoa, 1994.; Includes bibliographical references (leaves 177-182).; Microfiche.; xvii, 182 leaves, bound ill. 29 cm Sat, 01 Jan 1994 00:00:00 GMT http://hdl.handle.net/10125/9751 1994-01-01T00:00:00Z Fossorier, Marc P. C http://hdl.handle.net/10125/9750 Thesis (Ph. D.)--University of Hawaii at Manoa, 1994.; Includes bibliographical references (leaves 181-191).; Microfiche.; xvi, 191 leaves, bound ill. 29 cm Sat, 01 Jan 1994 00:00:00 GMT http://hdl.handle.net/10125/9750 1994-01-01T00:00:00Z Chêng, Tsê http://hdl.handle.net/10125/9749 Thesis (Ph. D.)--University of Hawaii at Manoa, 1994.; Includes bibliographical references (leaves 159-166).; Microfiche.; xiv, 166 leaves, bound ill. 29 cm Sat, 01 Jan 1994 00:00:00 GMT http://hdl.handle.net/10125/9749 1994-01-01T00:00:00Z Bist, Anurag http://hdl.handle.net/10125/9748 Thesis (Ph.D.)--University of Hawaii at Manoa, 1994.; Includes bibliographical references (leaves 212-216).; Microfiche.; xiii, 216 leaves, bound ill. 29 cm Sat, 01 Jan 1994 00:00:00 GMT http://hdl.handle.net/10125/9748 1994-01-01T00:00:00Z Rajpal, Sandeep http://hdl.handle.net/10125/9747 Thesis (Ph. D.)--University of Hawaii at Manoa, 1992.; Includes bibliographical references (leaves 111-117); Microfiche.; x, 117 leaves, bound ill. 29 cm Wed, 01 Jan 1992 00:00:00 GMT http://hdl.handle.net/10125/9747 1992-01-01T00:00:00Z Morelos-Zaragoza, Robert Henry