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Author: David J. Helfand
Publisher: Columbia University Press
ISBN: 0231558686
Category : Science
Languages : en
Pages : 350
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Book Description
Atoms are unfathomably tiny. It takes fifteen million trillion of them to make up a single poppy seed—give or take a few billion. And there’s hardly anything to them: atoms are more than 99.9999999999 percent empty space. Yet scientists have learned to count these slivers of near nothingness with precision and to peer into their internal states. In looking so closely, we have learned that atoms, because of their inimitable signatures and imperturbable internal clocks, are little archives holding the secrets of the past. David J. Helfand reconstructs the history of the universe—back to its first microsecond 13.8 billion years ago—with the help of atoms. He shows how, by using detectors and reactors, microscopes and telescopes, we can decode the tales these infinitesimal particles tell, answering questions such as: Is a medieval illustrated prayer book real or forged? How did maize cultivation spread from the highlands of central Mexico to New England? What was Earth’s climate like before humans emerged? Where can we find clues to identify the culprit in the demise of the dinosaurs? When did our planet and solar system form? Can we trace the births of atoms in the cores of massive stars or even glimpse the origins of the universe itself? A lively and inviting introduction to the building blocks of everything we know, The Universal Timekeepers demonstrates the power of science to unveil the mysteries of unreachably remote times and places.
Author: David J. Helfand
Publisher: Columbia University Press
ISBN: 0231558686
Category : Science
Languages : en
Pages : 350
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Book Description
Atoms are unfathomably tiny. It takes fifteen million trillion of them to make up a single poppy seed—give or take a few billion. And there’s hardly anything to them: atoms are more than 99.9999999999 percent empty space. Yet scientists have learned to count these slivers of near nothingness with precision and to peer into their internal states. In looking so closely, we have learned that atoms, because of their inimitable signatures and imperturbable internal clocks, are little archives holding the secrets of the past. David J. Helfand reconstructs the history of the universe—back to its first microsecond 13.8 billion years ago—with the help of atoms. He shows how, by using detectors and reactors, microscopes and telescopes, we can decode the tales these infinitesimal particles tell, answering questions such as: Is a medieval illustrated prayer book real or forged? How did maize cultivation spread from the highlands of central Mexico to New England? What was Earth’s climate like before humans emerged? Where can we find clues to identify the culprit in the demise of the dinosaurs? When did our planet and solar system form? Can we trace the births of atoms in the cores of massive stars or even glimpse the origins of the universe itself? A lively and inviting introduction to the building blocks of everything we know, The Universal Timekeepers demonstrates the power of science to unveil the mysteries of unreachably remote times and places.
Author: Willis Isbister Milham
Publisher:
ISBN:
Category : Clocks and watches
Languages : en
Pages : 650
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Book Description
Author: Truls Wyller
Publisher: Reaktion Books
ISBN: 1789142725
Category : Philosophy
Languages : en
Pages : 153
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Book Description
We refer to time constantly, and we compulsively measure its passing—but do we know what it actually is? In What Is Time?, Truls Wyller enquires into time’s complex nature, juxtaposing the latest scientific theories with our personal experience of chronology. The book examines the notion of time in physics, history, religion, anthropology, philosophy, and literature, and Wyller concludes by proposing his own theory of time: that the temporal character of any series of events is essentially practical and derived from human life. Written from a philosophical perspective, What Is Time? gives an accessible, rounded portrait of the nature of time, and it is essential reading for those who wish to gain a deeper understanding of the motion of our everyday existence.
Author: Chad Orzel
Publisher: BenBella Books
ISBN: 1953295940
Category : Science
Languages : en
Pages : 305
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Book Description
2022 NATIONAL INDIE EXCELLENCE AWARDS WINNER — HISTORY: GENERAL ". . . inherently interesting, unique, and highly recommended addition to personal, professional, community, college, and academic library Physics of Time & Scientific Measurement history collections, and supplemental curriculum studies lists.” —Midwest Book Review "A wonderful look into understanding and recording time, Orzel’s latest is appropriate for all readers who are curious about those ticks and tocks that mark nearly every aspect of our lives." —Booklist “A thorough, enjoyable exploration of the history and science behind measuring time.” —Foreword Reviews It’s all a matter of time—literally. From the movements of the spheres to the slipperiness of relativity, the story of science unfolds through the fascinating history of humanity’s efforts to keep time. Our modern lives are ruled by clocks and watches, smartphone apps and calendar programs. While our gadgets may be new, however, the drive to measure and master time is anything but—and in A Brief History of Timekeeping, Chad Orzel traces the path from Stonehenge to your smartphone. Predating written language and marching on through human history, the desire for ever-better timekeeping has spurred technological innovation and sparked theories that radically reshaped our understanding of the universe and our place in it. Orzel, a physicist and the bestselling author of Breakfast with Einstein and How to Teach Quantum Physics to Your Dog continues his tradition of demystifying thorny scientific concepts by using the clocks and calendars central to our everyday activities as a jumping-off point to explore the science underlying the ways we keep track of our time. Ancient solstice markers (which still work perfectly 5,000 years later) depend on the basic astrophysics of our solar system; mechanical clocks owe their development to Newtonian physics; and the ultra-precise atomic timekeeping that enables GPS hinges on the predictable oddities of quantum mechanics. Along the way, Orzel visits the delicate negotiations involved in Gregorian calendar reform, the intricate and entirely unique system employed by the Maya, and how the problem of synchronizing clocks at different locations ultimately required us to abandon the idea of time as an absolute and universal quantity. Sharp and engaging, A Brief History of Timekeeping is a story not just about the science of sundials, sandglasses, and mechanical clocks, but also the politics of calendars and time zones, the philosophy of measurement, and the nature of space and time itself. For those interested in science, technology, or history, or anyone who’s ever wondered about the instruments that divide our days into moments: the time you spend reading this book may fly, and it is certain to be well spent.
Author: Scott Alan Johnston
Publisher: McGill-Queen's Press - MQUP
ISBN: 0228009634
Category : Science
Languages : en
Pages : 304
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Book Description
Until the nineteenth century all time was local time. On foot or on horseback, it was impossible to travel fast enough to care that noon was a few minutes earlier or later from one town to the next. The invention of railways and telegraphs, however, created a newly interconnected world where suddenly the time differences between cities mattered. The Clocks Are Telling Lies is an exploration of why we tell time the way we do, demonstrating that organizing a new global time system was no simple task. Standard time, envisioned by railway engineers such as Sandford Fleming, clashed with universal time, promoted by astronomers. When both sides met in 1884 at the International Meridian Conference in Washington, DC, to debate the best way to organize time, disagreement abounded. If scientific and engineering experts could not agree, how would the public? Following some of the key players in the debate, Scott Johnston reveals how people dealt with the contradictions in global timekeeping in surprising ways – from zealots like Charles Piazzi Smyth, who campaigned for the Great Pyramid to serve as the prime meridian, to Maria Belville, who sold the time door to door in Victorian London, to Moraviantown and other Indigenous communities that used timekeeping to fight for autonomy. Drawing from a wide range of primary sources, The Clocks Are Telling Lies offers a thought-provoking narrative that centres people and politics, rather than technology, in the vibrant story of global time telling.
Author: M. Shawn Petersen
Publisher: Simon and Schuster
ISBN: 1582707081
Category : Juvenile Fiction
Languages : en
Pages : 363
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Book Description
A middle-grade fantasy novel about a half-angel, half-mermaid discovering her identity and fighting to protect the Laws of the Universe and the fate of the realms of land, sea and sky from the forces of evil. From the shore, the sky, and the depths of the sea, an epic adventure awaits. Stella Merriss has never felt like she belonged anywhere—her family was always on the run. During a daring escape her parents suddenly disappear into stormy, shark-infested waters. Alone and unsure of her future, she learns the truth: that she’s actually half angel, half mermaid. Stella has no choice but to join an elite angel apprenticeship program where—despite having to hide her illegal dual nature—she finally feels as though she has found a home. But villainous forces are gathering to strike against Stella’s newfound home and attack the three Timekeepers who spin and weave the fateful Thread of Life. Evil Lord Sylvain and his army will stop at nothing to corrupt the Laws of the Universe and bend them toward his own vile agenda. A child of land, sea, and sky is the only obstacle standing in his way. In this battle between good and evil, Stella and her friends must defend against the armies of Lord Sylvain or see the realms of land, sea, and sky plunged into chaos.
Author: National Measurement Laboratory (U.S.). Time and Frequency Division
Publisher:
ISBN:
Category : Frequencies of oscillating systems
Languages : en
Pages : 272
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Book Description
Author: C. S. Unnikrishnan
Publisher: CRC Press
ISBN: 1000522717
Category : Science
Languages : en
Pages : 374
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Book Description
This book is unique and exceptional in dealing with the notion of physical time rigorously, both logically and empirically. The central theme is the intimate relation between physical time and cosmic gravity. It establishes and explains, in an accessible manner, the one crucial physical fact that has been missed in the development of modern physics—that the enormous gravity of the matter and energy in the Universe is the controller and cause of the relativistic time. The material in the book is accurate and free of the ambiguities in the discussion of time and its modifications (dilation), synchronization of clocks, and simultaneity. The contents go beyond the current theories of relativity that fail to incorporate the cosmic gravity in their structure. The discussion of clocks in satellite navigational systems (like the GPS) is the most complete and accurate. The book offers several new insights, and it is the only available treatise on the complete physical truth about time. The contents are addressed to a wide range of readers, from general readers and students to experienced researchers, and will also appeal well to philosophers and historians of physics. This book has the enabling quality to deal with difficult questions about physical time, with unprecedented clarity and without paradoxes.
Author: Hermann Kopetz
Publisher: Springer Science & Business Media
ISBN: 0306470551
Category : Computers
Languages : en
Pages : 347
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Book Description
7. 6 Performance Comparison: ET versus TT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 7. 7 The Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Points to Remember . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 Bibliographic Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Review Questions and Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 Chapter 8: The Time-Triggered Protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 8. 1 Introduction to Time-Triggered Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 8. 2 Overview of the TTP/C Protocol Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 8. 3 TheBasic CNI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 Internal Operation of TTP/C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 8. 4 8. 5 TTP/A for Field Bus Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Points to Remember. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Bibliographic Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 Review Questions and Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 Chapter 9: Input/Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 9. 1 The Dual Role of Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 9. 2 Agreement Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 9. 3 Sampling and Polling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 9. 4 Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 9. 5 Sensors and Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 9. 6 Physical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Points to Remember. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Bibliographic Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Review Questions and Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Chapter 10: Real-Time Operating Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 10. 1 Task Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 10. 2 Interprocess Communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 10. 3 Time Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 10. 4 Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 10. 5 A Case Study: ERCOS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 Points to Remember. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 Bibliographic Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 Review Questions and Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 Chapter 11: Real-Time Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227 11. 1 The Scheduling Problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 11. 2 The Adversary Argument. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 11. 3 Dynamic Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 x TABLE OF CONTENTS 11. 4 Static Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 Points to Remember. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 Bibliographic Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Review Questions and Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Chapter 12: Validation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 12. 1 Building aConvincing Safety Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 12. 2 Formal Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248 12. 3 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Author: Steven P. Snyder
Publisher: Xlibris Corporation
ISBN: 147716488X
Category : Science
Languages : en
Pages : 467
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Book Description
Fragile Smile Book I
