Channel coding for high speed links

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2008.Includes bibliographical references (p. 139-144).This thesis explores the benefit of channel coding for high-speed backplane or chip-to-chip interconnects, referred to as the high-speed links. Although both power-constrained and bandwidth-limited, the high-speed links need to support data rates in the Gbps range at low error probabilities. Modeling the high-speed link as a communication system with noise and intersymbol interference (ISI), this work identifies three operating regimes based on the underlying dominant error mechanisms. The resulting framework is used to identify the conditions under which standard error control codes perform optimally, incur an impractically large overhead, or provide the optimal performance in the form of a single parity check code. For the regime where the standard error control codes are impractical, this thesis introduces low-complexity block codes, termed pattern-eliminating codes (PEC), which achieve a potentially large performance improvement over channels with residual ISI. The codes are systematic, require no decoding and allow for simple encoding. They can also be additionally endowed with a (0, n - 1) run-length-limiting property. The simulation results show that the simplest PEC can provide error-rate reductions of several orders of magnitude, even with rate penalty taken into account. It is also shown that channel conditioning, such as equalization, can have a large effect on the code performance and potentially large gains can be derived from optimizing the equalizer jointly with a pattern-eliminating code. Although the performance of a pattern-eliminating code is given by a closed-form expression, the channel memory and the low error rates of interest render accurate simulation of standard error-correcting codes impractical. This work proposes performance estimation techniques for coded high-speed links, based on the underlying regimes of operation.(cont)It also introduces an efficient algorithm for computing accurate marginal probability distributions of signals in a coded high-speed link.by Natasa Blitvic.S.M

Performance Analysis of Preemption Algorithms in an IDNX Circuit Switch Communications Network

Access to communication networks is increasing rapidly. The increase access to these networks results in delays and at times loss of data. At times of peak traffic or when trunks or nodes are down, very important customers\u27 communications requirements are not met. One way to combat this problem is to prioritize the network and provide different levels of grade of service (GOS) for each priority. Call preemption provides an effective method of obtaining different levels of GOS. This research seeks to design the best circuit switch communications network preemption model for the DoD by analyzing previously developed preemption algorithms. Four simulation network models are developed. The grades of service per priority are obtained as the network capacity decreases and as the calls generated in node 0 increases. The analysis of preemption network models is based on the grade of service, average number of preemptions, and average network bandwidth. The networks are simulated under the same input parameters. The analysis showed that preemption can significantly lower the grade of service for high priority customers in a congested network. The best configuration preemption model depends on the bandwidth flexibility of the network and the goals of the communications network organization

Photonic Non-destructive Measurement Methods for Investigating the Evolution of Polar Firn and Ice

When snow falls on glaciers or ice sheets, it persists for many tens, hundreds and sometimes thousands of years before becoming ice. The granular material in between fresh snow and glacial ice is known as firn and is generally 50 to 100 m thick over polar ice sheets. The compaction mechanism of firn into ice (called densification) has important glaciological ramifications in determination of ice sheet stability and related sea level rise effects via remote sensing altimetry. Firn densification is also important for correctly interpreting ice core paleoclimate records, especially those analyzing gases trapped in air bubbles within the glacial ice. Densification is thought to depend strongly on microstructure: the sizes, shapes, orientations and inter-particle bonds of the ice grains that make up polar firn. Microstructure-dependent densification is poorly understood and occurs in the region where two-thirds of the overall densification takes place. This work focuses on developing non-destructive methods for simultaneously evaluating changes in both the bulk density and microstructure of polar firn to better understand structuredependent densification processes. The first method is an automated density gauge which uses gamma-ray transmission methods to non-destructively produce high resolution (3.3 mm) and high precision (±4 kg m-3) density profiles of firn and ice cores. This instrument was used to collect a density profile for the first 160 m of the West Antarctic Ice Sheet Divide WDC06A deep ice core. The second method involves optical scattering measurements on firn and ice cores to determine the important microstructural parameters of ice grain and air bubble size and air-ice interface surface area. These measurements are modeled using both Monte Carlo radiative transfer and ray-tracing geometric optics methods, and are then tested against experiment using digital photography of the WDC06A core. Combining the results of both bulk density and optical scattering measurements for the same core reveals that microstructure-dependent densification did occur at this site and is readily detectable by purely photonic methods. This work lays the theoretical and experimental foundations for a novel, non-destructive and field deployable instrument for further study of structure-dependent firn densification

Reduction of mobile phone interference in tele-ECG monitoring.

by Hung King Fai Kevin.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.Includes bibliographical references (leaves 82-85 (2nd gp.)).Abstracts in English and Chinese.ACKNOWLEDGEMENT --- p.iiABSTRACT --- p.iii摘要 --- p.vTABLE OF CONTENTS --- p.viChapter CHAPTER 1 --- INTRODUCTION --- p.1Chapter 1.1 --- OBJECTIVES --- p.1Chapter 1.2 --- NEED FOR PATIENT-MONITORING SYSTEM --- p.1Chapter 1.2.1 --- Aging Population --- p.1Chapter 1.2.2 --- Increasing Population with Heart Diseases --- p.2Chapter 1.3 --- ECG BASICS --- p.3Chapter 1.4 --- EXISITING ECG-MONITORING TECHNOLOGIES --- p.4Chapter 1.5 --- CHALLENGES IN PATIENT-MONITORING --- p.5Chapter 1.6 --- DEVELOPMENT OF AN ECG-MONITORING SYSTEM --- p.6Chapter 1.6.1 --- Overall Structure --- p.6Chapter 1.6.2 --- Considerations --- p.7Chapter CHAPTER 2 --- EMI FILTERS IN ECG ACQUISITION CIRCUIT --- p.8Chapter 2.1 --- OVERVIEW OF NOISE SOURCES IN ECG ACQUISITION --- p.8Chapter 2.1.1 --- Other Biopotentials --- p.8Chapter 2.1.2 --- Motion Artifact --- p.8Chapter 2.1.3 --- Power-line Interference --- p.10Chapter 2.1.4 --- High-Frequency Electromagnetic Interference --- p.15Chapter 2.2 --- EMI FILTERS --- p.16Chapter 2.2.1 --- Introduction to EMI Filters --- p.16Chapter 2.2.2 --- Types of EMI Filter --- p.17Chapter 2.2.3 --- EMI Filters in ECG Monitoring --- p.21Chapter 2.3 --- MODELING OF INTERFERENCE IN ECG-MONITORING SYSTEM --- p.22Chapter 2.3.1 --- Model and Parameters --- p.22Chapter 2.3.2 --- Method --- p.24Chapter 2.3.2 --- Results --- p.27Chapter 2.3.3 --- Discussion --- p.30Chapter 2.4 --- BUILDING AN ECG ACQUISITION CIRCUIT WITH EMI FILTERS --- p.30Chapter 2.4.1 --- Purpose --- p.30Chapter 2.4.2 --- Experimental Setup and Method --- p.30Chapter 2.4.3 --- Results --- p.32Chapter 2.4.4 --- Discussion --- p.46Chapter CHAPTER 3 --- ADAPTIVE FILTER --- p.48Chapter 3.1 --- OBJECTIVE --- p.48Chapter 3.2 --- INTRODUCTION TO ADAPTIVE FILTER --- p.48Chapter 3.3 --- METHOD --- p.50Chapter 3.4 --- RESULTS --- p.52Chapter 3.5 --- DISCUSSION --- p.57Chapter CHAPTER 4 --- WAP-BASED TELEMEDICINE APPLICATIONS --- p.59Chapter 4.1 --- INTRODUCTION TO TELEMEDICINE --- p.59Chapter 4.2 --- INTRODUCTION TO WAP --- p.59Chapter 4.3 --- WAP APPLICATIONS --- p.60Chapter 4.4 --- SYSTEM IMPLEMENTATION --- p.63Chapter 4.4.1 --- Overall Structure --- p.63Chapter 4.4.2 --- Relational Database --- p.63Chapter 4.4.3 --- Program Flow --- p.64Chapter 4.4.4 --- ECG Browsing and Feature Extraction --- p.70Chapter 4.5 --- EMULATION --- p.72Chapter 4.6 --- EXPERIENCE WITH WAP PHONE --- p.74Chapter 4.7 --- DISCUSSION AND CONCLUSION --- p.75Chapter CHAPTER 5: --- CONCLUSION AND FUTURE WORK --- p.77Chapter 5.1 --- CONCLUSION --- p.77Chapter 5.2 --- FUTURE WORK --- p.77Chapter 5.3 --- MARKET ANALYSIS --- p.79BIBLIOGRAPHY --- p.8

Catalog of particles and fields data 1966-1973

For abstract, see N75-24211

The Glass Jaw. The Presence of Incivility, Conflict, and Bullying in Disempowering Workplaces: A Study of Middle-Level Managers in HEIs

Middle-level managers at HEIs experience stress-related conflicts that include incivility and bullying. There is a gap in the literature regarding middle-level managers’ contributions to improving interpersonal relationships in the workplace and the type of conflict-management training most suited to middle-level managers in HEIs when incivility, conflict, and bullying are present. This qualitative design study sought to understand conflict management from the perspective of HEI middle-level managers within the manager-to-subordinate relationship. The study examined the lived experiences of 10 HEI middle-level managers with coded data revealing four overall themes: structural challenges, sources of conflict, conflict training, and managing conflict. The results of this study showed that middle-level managers did not utilize knowledge obtained in conflict-management training, instead preferring to create their conflictmanagement tactics and strategies. The study’s results may help increase knowledge of conflict management for middle-level managers in HEIs and a greater understanding of the tools needed to work through incivility and bullying

Faith in view: religion and pirituality in factual British television 2000-2009

This thesis explores the nature of, and developments in, the coverage of religion and spirituality in factual British television programming 2000-2009, focusing on mainstream terrestrial networks (BBC, ITV, Channel 4, Five) with a public service remit. The study employs a mixed-method approach with an emphasis on discourse. Working within a broadly Critical Discourse Analysis (CDA) framework, it explores discourses around religion/spirituality, identity and nationality across a range of environments – from the programmes themselves to audience discussion (in focus groups, questionnaires, forum and Twitter discussions, YouTube comments and blogs) and industry accounts of production (in policies, guidelines, publicity and interviews with several of those involved at different stages of the production process). The theoretical context of this study includes debates over the ‘secularisation thesis’, the rise of ‘fundamentalism’, the individualisation of religion and the apparent interest in ‘spirituality’ as opposed to ‘religion’, the role of public service broadcasting, issues of media representation of minorities, and developments within British factual television genres. The study concludes that, despite public service commitments, there is a lack of diversity in the portrayal of religion and spirituality within mainstream factual British television, with Christianity, Islam and Atheism dominating coverage. All faiths are represented by a limited repertoire of signifiers. Audiences, both those who have been researched for this study and those who feature in research by the broadcasters and Ofcom, often complain about what they perceive as 'misrepresentation', whilst at the same time discussing 'other' people in stereotypical terms. Within all of the discursive contexts studied, there is a construction of Britain as a liberal, tolerant, moderate place, where spiritual/religious belief is acceptable as long as it operates within particular parameters. When beliefs and practices do not conform to these standards, they are exoticised, ridiculed or presented as dangerous, and often linked to other nations, thus emphasising how they are not a British way of expressing one's spirituality. However, I argue that the problematic nature of these constructions is in part a result of the complex interaction between audiences, programme makers, policy, academic discourse and media texts. Each area of discourse informs the other, replicating and reinforcing notions of Britishness, religion and spirituality across multiple contexts

The Political Economy of Large-Scale Land Acquisition in Sierra Leone: An Empirical Application of a Computable General Political Economy Equilibrium Modelling Approach

The transfer of large areas of agricultural land from small-holder farmers to international investors, particularly in Sub-Saharan Africa, has become one of the mostly contested topics in International development circles. Even though there is a broad agreement among both critics and opponents that these land transfers have profound welfare implications, there is a dearth in the academic literature about their distributional and welfare effects at both the household and country level. Moreover, beyond pure economic anaylsis, political economy analysis have rarely been provided. This thesis, which is comprised of four articles, attempts to fill these gaps by adopting a Computational General Political Economy Equilibrium (CGPE) Modelling approach to undertake an empirical political economy analysis of the role of political preferences, policy beliefs and political power in the large-scale land acquisition policy processes in Sierra Leone. It also undertakes a quantitative assessment of the distributional and welfare effects of large-scale land acquisition at both the household and country level in Sierra Leone. Our results suggest that even though some stakeholders put extremely high political weight on maximizing the profit of large-scale land investors, land market policies are not driven by land grabber preferences. Furthermore, land market policies would be only significantly inefficient if small-scale farmers hold rational expectation beliefs. These findings have significant implications for development institutions, and donor organisations seeking to promote stakeholder engagements and bolster evidence-based policy making in developing countries like Sierra Leone. We suggest that, to overcome the wide variance in the estimated policy beliefs among key policy stakeholders, a transdisciplinary research apprroach that allows for the scientifc and political community to interact and narrow policy belief differences, is required

Standardized development of computer software. Part 2: Standards

This monograph contains standards for software development and engineering. The book sets forth rules for design, specification, coding, testing, documentation, and quality assurance audits of software; it also contains detailed outlines for the documentation to be produced

Probabilistic accident consequence uncertainty analysis -- Uncertainty assessment for internal dosimetry. Volume 2: Appendices

The development of two new probabilistic accident consequence codes, MACCS and COSYMA, was completed in 1990. These codes estimate the consequence from the accidental releases of radiological material from hypothesized accidents at nuclear installations. In 1991, the US Nuclear Regulatory Commission and the Commission of the European Communities began cosponsoring a joint uncertainty analysis of the two codes. The ultimate objective of this joint effort was to systematically develop credible and traceable uncertainty distributions for the respective code input variables. A formal expert judgment elicitation and evaluation process was identified as the best technology available for developing a library of uncertainty distributions for these consequence parameters. This report focuses on the results of the study to develop distribution for variables related to the MACCS and COSYMA internal dosimetry models. This volume contains appendices that include (1) a summary of the MACCS and COSYMA consequence codes, (2) the elicitation questionnaires and case structures, (3) the rationales and results for the panel on internal dosimetry, (4) short biographies of the experts, and (5) the aggregated results of their responses