1,721,454 research outputs found
(correspondence) Azhar Ali
No full text都留からMahmood宛 Azhar Ali宛書簡あり。4件書簡オリジナルの所在: 一橋大学経済研究所資料室都留重人氏より寄贈1-A-2-15/2
Design of LDPC Decoder for Error Correction in Memory Devices
No full textNAND flash memories are used in large number of electronic devices for storing data. The ever increasing demand of the high storage in these devices has resulted in high density NAND flash memories. The high density is achieved through the process of continuous technology scaling and the use of multilevel cell (MLC) technology. In multilevel cell technology more than one bits are stored in a single cell of the flash memory. However, this increased storage density has come at a price of reduced reliability. The raw bit error rate has increased rapidly in high density flash memories, therefore, demanding more powerful error correcting codes. The bit error rate (BER) requirements in NAND flash memories are reported to be 10^−13 to 10^−16, after applying the error correcting code. The current practice is to use the hard decision error correcting codes in NAND flash memories, such as BCH codes. However, as the raw bit error rate is getting worse, these hard decision codes will not be able to achieve the BER requirements of these memories. Therefore, more powerful error correcting codes with soft decision decoding algorithm are required. Among the soft decision codes, low density parity check codes (LDPC) can be a promising candidate for error correction in high density NAND flash memories due to their excellent error correction performance close to the Shannon limit. LDPC codes employed in NAND flash memories have large block lengths and very high code rate and should show good error correcting and error floor performance. Evaluating the error floor performance of these codes at very low frame error rates, typically around 10^−9 to 10^−10, require the use of high speed hardware simulators. Due to the reconfigurability and high speed, field programmable gate arrays (FPGAs) are largely used for evaluating the performance of LDPC codes. This thesis presents an FPGA based simulator system for evaluating the error correction and error floor performance of regular quasi cyclic (QC) LDPC Codes, for the application of large page size MLC NAND flash memories. Particularly, we targeted the algebraic QC-LDPC codes, which have high code rates and good error correcting and error floor performance. A generalized, high throughput and resource efficient hardware implementation of the QC-LDPC encoder and the decoder is given on FPGA. The proposed decoder can decode any regular QC-LDPC code including very high circulant weight QC-LDPC codes, such as euclidean geometry (EG) LDPC codes. The generalized and high throughput implementation of such large circulant weight QC-LDPC codes is not reported previously in the open literature. Moreover, the encoder and decoder hardware implementations are given on FPGA for very large page size (8 KB) of NAND flash memory, which are also not dealt previously in the open literature. A high speed and high quality floating point additive white Gaussian noise channel is implemented on FPGA using the high level synthesis method. The high level synthesis is used to rapidly prototype the channel on FPGA and to lower the development time of the LDPC simulator system. The very low consumption of the logic resources by the channel also enabled us to instantiate many channel modules in parallel, resulting in high throughput of the simulator. This thesis also presents the FPGA implementation and simulation results of two algebraic QC-LDPC codes for the page size 8 KB of NAND flash memory. Simulation results show good error correcting and error floor performance of the developed codes making them a promising candidate for error correction in NAND flash memorie
Mahir Seni Khat, seni kaligrafi mengikut pengkaedahan jawi
Full text linkBuku ini dirangka sbg latihan pengukuhan kpd seni kalingrafi yg diajar di peringkat sekolah.Buku ini dipersembahkan dlm bentuk tulisan jawi berdasarkan pengkaedahan jawi baharu.Kombinasi antara seni kalingrafi dgn pengkaedahan jawi baharu perlu dijalin supaya nilai seni lebih menyerlah dan kefahaman tentang ejaan jawi yg betul dapat diperkukuh.Contoh dan latihan yg disediakan juga sesuai dijadikan bahan rangsangan yg menarik serta berkesan
FPGA accelerator of algebraic quasi cyclic LDPC codes for NAND flash memories
Full text linkIn this article, the authors implement an FPGA simulator that accelerates the performance evaluation of very long QC-LDPC codes, and present a novel 8-KB LDPC code for NAND flash memory with better performance
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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