34,149 research outputs found
uFLIP: Understanding Flash IO Patterns
Does the advent of flash devices constitute a radical change for secondary
storage? How should database systems adapt to this new form of secondary
storage? Before we can answer these questions, we need to fully understand the
performance characteristics of flash devices. More specifically, we want to
establish what kind of IOs should be favored (or avoided) when designing
algorithms and architectures for flash-based systems. In this paper, we focus
on flash IO patterns, that capture relevant distribution of IOs in time and
space, and our goal is to quantify their performance. We define uFLIP, a
benchmark for measuring the response time of flash IO patterns. We also present
a benchmarking methodology which takes into account the particular
characteristics of flash devices. Finally, we present the results obtained by
measuring eleven flash devices, and derive a set of design hints that should
drive the development of flash-based systems on current devices.Comment: CIDR 200
Safety in Combat Sports: Is Boxing Safer?
Combat sports are widely regarded as one of the most dangerous sports or activities an athlete can participate in. Leading the way in terms of popularity is the sport of boxing and Mixed Martial Arts (MMA). The resounding consensus among combat sports fans and athletes is that the sport of boxing is the safest option, but with the more recent discovery of Chronic traumatic encephalopathy (CTE) and the brain damage that occurs because of repeated strikes to the head, it appears that boxing is the most dangerous combat sport. The reason for my research project is to see what sport is in fact is the most dangerous and what makes it so detrimental to an athlete’s health. Scientific breakthroughs and testing have been developing regarding the effects of the human brain after receiving blows to the head and concussions all together. Keywords: Combat Sports, CT
B+-tree Index Optimization by Exploiting Internal Parallelism of Flash-based Solid State Drives
Previous research addressed the potential problems of the hard-disk oriented
design of DBMSs of flashSSDs. In this paper, we focus on exploiting potential
benefits of flashSSDs. First, we examine the internal parallelism issues of
flashSSDs by conducting benchmarks to various flashSSDs. Then, we suggest
algorithm-design principles in order to best benefit from the internal
parallelism. We present a new I/O request concept, called psync I/O that can
exploit the internal parallelism of flashSSDs in a single process. Based on
these ideas, we introduce B+-tree optimization methods in order to utilize
internal parallelism. By integrating the results of these methods, we present a
B+-tree variant, PIO B-tree. We confirmed that each optimization method
substantially enhances the index performance. Consequently, PIO B-tree enhanced
B+-tree's insert performance by a factor of up to 16.3, while improving
point-search performance by a factor of 1.2. The range search of PIO B-tree was
up to 5 times faster than that of the B+-tree. Moreover, PIO B-tree
outperformed other flash-aware indexes in various synthetic workloads. We also
confirmed that PIO B-tree outperforms B+-tree in index traces collected inside
the Postgresql DBMS with TPC-C benchmark.Comment: VLDB201
Why Tangibility Matters: A Design Case Study of At-Risk Children Learning to Read and Spell
Tangibles may be effective for reading applications. Letters can be represented as 3D physical objects. Words are spatially organized collections of letters. We explore how tangibility impacts reading and spelling acquisition for young Anglophone children who have dyslexia. We describe our theory-based design rationale and present a mixedmethods case study of eight children using our PhonoBlocks system. All children made significant gains in reading and spelling on trained and untrained (new) words, and could apply all spelling rules a month later. We discuss the design features of our system that contributed to effective learning processes, resulting in successful learning outcomes: dynamic colour cues embedded in 3D letters, which can draw attention to how letter(s) position changes their sounds; and the form of 3D tangible letters, which can enforce correct letter orientation and enable epistemic strategies in letter organization that simplify spelling tasks. We conclude with design guidelines for tangible reading systems
Eight is not enough: a historical, cultural, and philosophical analysis of the flash mob
In 2003, writer and cultural critic Bill Wasik stunned the world with his newest experiment, the MOB Project, which flooded the streets of New York City with strange performances quickly labeled “flash mobs” by participants and local media. With the goal of understanding the communicative purpose and function of these new performance events, this project analyzes the flash mob through the lenses of performance studies, rhetorical studies, cultural studies, and continental philosophy. Drawing from genealogical research, rhetorical analyses, and critical philosophy, I argue the flash mob is a new form of performance serving as a locus of community, creativity, and politics in an age overrun by spectacle and surveillance. Moreover, whether created as complex communal in-jokes or a modern form of cultural critique, flash mobs act as elaborate pranks played out within the quasi-public realm of the capitalist city, exposing its heretofore unrealized methods of operation. Through a critical application of the theories of philosophers Michel de Certeau, Michel Foucault, Gilles Deleuze and Felix Guattari, I analyze the ability of Bill Wasik’s flash mobs to highlight the dominant strategies of surveillance, standardization, and structure operating within the capitalist system. In so doing, I explore the tactical nature of the flash mob as a performance event
- …