Network coding aware queue management in multi-rate wireless networks

In this thesis we focus on network coding for unicast flows, in particular we take into consideration the COPE architecture. We study what happens when two nodes transmit with different rates and we propose a Markov chain to model this scenario. Furthermore, we propose a queue management algorithm to increase the coding opportunity and the throughput of the network. In COPE, a node codes two or more packets together when packets are headed to different nexthops. When there are just packets for the same nexthop, a node loses a coding opportunity. The queue management algorithm increases the coding opportunity prioritizing the channel access of sender nodes based on the queue information and on PER of the links. We simulate this algorithm on top of COPE in a multi rate scenario with NS 2 and we show that our algorithm yields throughput gains of up to 57\% compared to COP

A semantic methodology for (un)structured digital evidences analysis

Nowadays, more than ever, digital forensics activities are involved in any criminal, civil or military investigation and represent a fundamental tool to support cyber-security. Investigators use a variety of techniques and proprietary software forensic applications to examine the copy of digital devices, searching hidden, deleted, encrypted, or damaged files or folders. Any evidence found is carefully analysed and documented in a "finding report" in preparation for legal proceedings that involve discovery, depositions, or actual litigation. The aim is to discover and analyse patterns of fraudulent activities. In this work, a new methodology is proposed to support investigators during the analysis process, correlating evidences found through different forensic tools. The methodology was implemented through a system able to add semantic assertion to data generated by forensics tools during extraction processes. These assertions enable more effective access to relevant information and enhanced retrieval and reasoning capabilities

A fault tolerant grid generation technique

Automatic and parallel mesh generation has been highlighted as a bottleneck for large scale automated Computational Fluid Dynamics analysis. The desire for large scale automated CFD is driven by the growing computational capabilities in large scale supercomputers. Unfortunately, as compute clusters grow in size, they also suffer more failures. Left unchecked, the increased frequency of failures may stymie any efforts to fully utilize these machines. This work aims to tackle one component required for automated large scale engineering analysis by developing a fault tolerant mesh generator. The mesh generator uses a novel com- munication layer written using the transport layer ZeroMQ and is made fault tolerant through an integrated in-memory checkpoint and recovery strategy. Benefits of using in-memory checkpoints vs traditional in-disk checkpoints are discussed. By relying on in-memory checkpointing, it is demonstrated that the mesh generator to be capable of generating Cartesian meshes in parallel. The generator continues to operate even while the compute cluster it is running suffers failures. The generator is shown to be high performing, including being capable of generating an 8.6 billion element mesh in just over 1 minute while creating multiple in-memory checkpoints

"With the quiet sturdy strength of the folk of an older time": an archaeological approach to time, place-making, and heritage construction at the Fairbanks House, Dedham, Massachusetts

Thesis (Ph.D.)--Boston UniversityHistoric houses function as the stages for, and central figures in, processes of place-making and heritage construction. I offer the case site of the Fairbanks House (completed in 1641) in Dedham, Massachusetts as the subject of my investigation into these issues. Touted as the "oldest timber frame house in North America," the Fairbanks House is widely regarded as a significant example of early colonial architecture in the United States; it has operated as a house museum since it was purchased by the Fairbanks Family in America, Inc. stewardship group in 1904. This study expands beyond antiquity to include all eight generations of Fairbanks families who lived on the property. I argue that longevity, and a durational perspective that links the past with the present, is equally vital to peoples' understanding and appreciation. I trace the biography of the Fairbanks House from its creation in the early 17th century to its current use as a heritage site. This perspective emphasizes the continued saliency of accumulated individual decisions and actions, reified by both material culture and immaterial processes such as tradition and memory. I use archaeological, architectural, documentary, and oral sources to reconstruct the landscape of the Fairbanks farm and I demonstrate how residents made day-to-day choices, such as land purchases or neighborly socializing, to improve their socio-economic standing and establish a future for their children. In doing so for eight generations, they established a legacy that was celebrated beginning in the 19th century, when Fairbanks women living in the house promoted their family's history through storytelling and published media. These processes of heritage construction remain continuous and personal, as shown by the results of an ethnographic study that I designed, which reveals that Fairbanks House museum visitors define historicity not through specific facts about the Fairbanks family but through their own narratives based on their engagement with the site's material culture. In addition to providing an important example of how generations of modestly-successful New England farmers adapted their surroundings to fit their values and goals, this study positions local house museums as dynamic spaces for creative, personal engagements with the past

Peto\u27s Paradox and the Evolution of Cancer Suppression

In order to successfully build and maintain a multicellular body, somatic cells must be constrained from proliferating uncontrollably and destroying the organism. If all mammalian cells were equally susceptible to oncogenic mutations and had identical tumor suppressor mechanisms, one would expect that the risk of cancer would be proportional to the body size and lifespan of a species. This is because a greater number of cells and cell divisions over a lifetime would increase the chance of accumulating mutations that result in malignant transformation. Peto’s paradox is the clash between the theory that cancer incidence should increase with body size and lifespan, and the observation that it does not. In this thesis, I present the first comprehensive survey of empirical evidence across mammals in support of Peto’s paradox in addition to computational models that explore the numerous hypotheses that may help resolve the paradox. I provide a detailed examination of tumor suppression in African elephants (Loxodonta africana) and show that the genome contains redundant copies of the tumor suppressor gene TP53. I give evidence that these redundant copies are actively transcribed and also observe an increased apoptotic response after exposure to ionizing radiation, which may be linked to the expression of these genes. Few genomes of large, long-lived organisms are currently available, which motivated my work to provide the sequence and de novo assembly of the humpback whale (Megaptera novaeangliae) genome. In this genome, I discovered a set of tumor suppressor genes that have evolved at an accelerated rate along the whale lineage, which is suggestive of adaptation. Additionally, I find one gene that has undergone convergent evolution between the African elephant and the humpback whale. The overarching goal of my research is to gain a better understanding of how evolution has suppressed cancer in large, long-lived organisms in the hopes of ultimately developing improved cancer prevention in humans

Blown to Bits: Your Life, Liberty, and Happiness After the Digital Explosion

382 p.Libro ElectrónicoEach of us has been in the computing field for more than 40 years. The book is the product of a lifetime of observing and participating in the changes it has brought. Each of us has been both a teacher and a learner in the field. This book emerged from a general education course we have taught at Harvard, but it is not a textbook. We wrote this book to share what wisdom we have with as many people as we can reach. We try to paint a big picture, with dozens of illuminating anecdotes as the brushstrokes. We aim to entertain you at the same time as we provoke your thinking.Preface Chapter 1 Digital Explosion Why Is It Happening, and What Is at Stake? The Explosion of Bits, and Everything Else The Koans of Bits Good and Ill, Promise and Peril Chapter 2 Naked in the Sunlight Privacy Lost, Privacy Abandoned 1984 Is Here, and We Like It Footprints and Fingerprints Why We Lost Our Privacy, or Gave It Away Little Brother Is Watching Big Brother, Abroad and in the U.S. Technology Change and Lifestyle Change Beyond Privacy Chapter 3 Ghosts in the Machine Secrets and Surprises of Electronic Documents What You See Is Not What the Computer Knows Representation, Reality, and Illusion Hiding Information in Images The Scary Secrets of Old Disks Chapter 4 Needles in the Haystack Google and Other Brokers in the Bits Bazaar Found After Seventy Years The Library and the Bazaar The Fall of Hierarchy It Matters How It Works Who Pays, and for What? Search Is Power You Searched for WHAT? Tracking Searches Regulating or Replacing the Brokers Chapter 5 Secret Bits How Codes Became Unbreakable Encryption in the Hands of Terrorists, and Everyone Else Historical Cryptography Lessons for the Internet Age Secrecy Changes Forever Cryptography for Everyone Cryptography Unsettled Chapter 6 Balance Toppled Who Owns the Bits? Automated Crimes—Automated Justice NET Act Makes Sharing a Crime The Peer-to-Peer Upheaval Sharing Goes Decentralized Authorized Use Only Forbidden Technology Copyright Koyaanisqatsi: Life Out of Balance The Limits of Property Chapter 7 You Can’t Say That on the Internet Guarding the Frontiers of Digital Expression Do You Know Where Your Child Is on the Web Tonight? Metaphors for Something Unlike Anything Else Publisher or Distributor? Neither Liberty nor Security The Nastiest Place on Earth The Most Participatory Form of Mass Speech Protecting Good Samaritans—and a Few Bad Ones Laws of Unintended Consequences Can the Internet Be Like a Magazine Store? Let Your Fingers Do the Stalking Like an Annoying Telephone Call? Digital Protection, Digital Censorship—and Self-Censorship Chapter 8 Bits in the Air Old Metaphors, New Technologies, and Free Speech Censoring the President How Broadcasting Became Regulated The Path to Spectrum Deregulation What Does the Future Hold for Radio? Conclusion After the Explosion Bits Lighting Up the World A Few Bits in Conclusion Appendix The Internet as System and Spirit The Internet as a Communication System The Internet Spirit Endnotes Inde