1,452 research outputs found
Probabilistic modeling of noise transfer characteristics in digital circuits
Device scaling, the driving force of CMOS technology, led to continuous
decrease in the energy level representing logic states. The resulting small
noise margins in combination with increasing problems regarding the supply
voltage stability and process variability creates a design conflict between
efficiency and reliability. This conflict is expected to rise more in future
technologies. Current research approaches on fault-tolerance architectures
and countermeasures at circuit level, unfortunately, cause a significant
area and energy penalty without guaranteeing absence of errors. To overcome
this problem, it seems to be attractive to tolerate bit errors at circuit
level and employ error handling methods at higher system levels. To do this,
an estimate of the bit error rate (BER) at circuit level is necessary. Due
to the size of the circuits, Monte Carlo simulation suffers from impractical
runtimes. Therefore the needed modeling scheme is proposed. The model allows
a probabilistic estimation of error rates at circuit level taking into
account statistical effects ranging from supply noise and electromagnetic
coupling to process variability within reasonable runtimes
Managing the patient with episodic sinus tachycardia and orthostatic intolerance
Patients with episodic sinus tachycardia and associated orthostatic intolerance present a diagnostic and management dilemma to the clinician. We define this group of disorders to include sinus node reentrant tachycardia (SNRT), inappropriate sinus tachycardia (IAST), and postural orthostatic tachycardia syndrome (POTS). After a brief review of the current understanding of the pathophysiology and epidemiology of this group of disorders, we focus on the diagnosis and management of IAST and POTS. Our approach attempts to recognize the considerable overlap in pathophysiology and clinical presentation between these two heterogeneous conditions. Thus, we focus on a mechanism-based workup and therapeutic approach. Sinus tachycardia related to identifiable causes should first be ruled out in these patients. Next, a basic cardiovascular and autonomic workup is suggested to exclude structural heart disease, identify a putative diagnosis, and guide therapy. We review both nonpharmacologic and pharmacologic therapy, with a focus on recent advances. Larger randomized control trials and further mechanistic studies will help refine management in the future
Quantitative comparison of performance analysis techniques for modular and generic network-on-chip
NoC-specific parameters feature a huge impact on performance and implementation costs of NoC. Hence, performance and cost evaluation of these parameter-dependent NoC is crucial in different design-stages but the requirements on performance analysis differ from stage to stage. In an early design-stage an analysis technique featuring reduced complexity and limited accuracy can be applied, whereas in subsequent design-stages more accurate techniques are required. <br><br> In this work several performance analysis techniques at different levels of abstraction are presented and quantitatively compared. These techniques include a static performance analysis using timing-models, a Colored Petri Net-based approach, VHDL- and SystemC-based simulators and an FPGA-based emulator. Conducting NoC-experiments with NoC-sizes from 9 to 36 functional units and various traffic patterns, characteristics of these experiments concerning accuracy, complexity and effort are derived. <br><br> The performance analysis techniques discussed here are quantitatively evaluated and finally assigned to the appropriate design-stages in an automated NoC-design-flow
Memorial to Charles Alexander Baskerville (1928â2009)
Charles Alexander Baskerville captured our imagination, as a senior colleague in the practice of engineering geology in New York City. âCharlieâ held the seat of master Big Apple Geologist during his matured career. He was the source, he knew the possibilities, he was aware of the pitfalls of this most geologically complex of American cities. His final work was his greatest reachâthe four bedrock geologic quadrangles of the city. Baskerville mapped New York City for more than fifty years. He was sought and given access to sites of bedrock and bedrock/ overburden interface on the various capitol construction projects undertaken by the City of New York including City Water Tunnel #3.
Charles Baskerville had a vision and a sense of duty about his profession: to make the most of his opportunity to practice and to teach applied geology in one of the most difficult of all territories known to geologistsâAmericaâs largest city. Professor Baskerville fully knew that the geologic complexities of New York City will never be known to the degree to which new and renovated engineered works can be insulated from huge potentials of cost impacts related to geologic conditions. What he did to improve this situation was to make the most of his determination to solve the emerging riddles and to teach many other geologists, engineers, and public officials to pay attention to what each generation of Big Apple geologists have left us as their legacy. Charlie will hold that record for the foreseeable future, for he worked smart, hard, and gave of his time and knowledge freely and openly
TUNNEL GEOLOGY AS SEEN BY GEOLOGISTS: MANHATTAN, NEW YORK CITY
Current exploratory boring operations in and around Manhattan, New York City are providing geologists and geotechnical engineers with a plethora of new and interesting geological information, which has not been previously reported. The rocks encountered, mostly medium to high-grade metamorphic rocks, with both mafic and felsic intrusives, are highly variable in competency and mechanical durability. One of the most frequently encountered rock types is a garnetiferous-muscovite-biotite schist which grades into schistose gneiss and displays a wide variety of structural, compositional, and textural attributes. Metamorphic minerals showing the variable degree of metamorphism include graphite, talc, garnet, kyanite, tourmaline, emory, and occasionally sillimanite. The presence of magnetite-rich zones within the muscovite-garnet schist suggests a mechanism for the concentration of iron during metamorphism. Concentrations of garnet both in the schist and intrusive pegmatite is perhaps indicative of anatectic melting of the protolith. Marble is the dominant rock type east of CAMERON\u27S LINE and it varies from pure white calcitic to dolomitic coarsely crystalline marble, to siliceous calcitic to dolomitic marble. In places, highly pyrite-rich zones, perhaps suggesting hydrothermal alteration of the parent rock due to subsequent mineral-rich fluid flow, are observed. The timing of the sulfide-rich fluid-flow through the original bedrock is yet to be determined. Partial dissolution of marble at various depths has resulted in void (cave) formation and has posed a threat to the boring operations. Rocks of lower abundance include amphibolite, granodiorite, quartzite, serpentinite, and aplite. The overall structural fabric is controlled by the Taconic and Acadian Orogenic events and manifested in the development of characteristic foliation, joint patterns, intrusives, and the degree of metamorphism of the protoliths
Hasbara 2.0: Israelâs Public Diplomacy in the Digital Age
The Internet has been a counter-public space for Palestinian liberation politics for over a decade, and digital technologies have become an increasingly important tool for solidarity groups across the world. However, the Israeli state and Zionist supporters worldwide are harnessing the same technologies and platforms to mobilize technology primarily to increase pro-Israel sentiments. The aims of this article are to examine hasbara [Israeli public diplomacy] through an exploration of similar diplomacy programmes; to illustrate how social media have affected the basic algorithms of hasbara; and to probe the assertions of hasbara in the light of pro-Palestinian solidarity. Through a study of public diplomacy, this article critically analyzes hasbara as a site of contestation and a method that is hampered by contradictions. On the one hand, there has been a massive growth in hasbara in recent yearsâindicated by the increase in funding for it and by its professionalized and centralized character; and on the other hand, hasbara has attracted sharp critiques in Israel for its reputed failures. To understand this contradiction, hasbara must be placed within the context of Israelâs settler-colonialism, which sets the state apart from other âpost-conflictâ states. This article reviews the methods utilized in hasbara, as well as their readjustment in the context of recent wars. Events in 2014 illustrate that hasbara actually destabilizes Israelâs diplomacy. Online journalism and the suppression of solidarity for Palestine together stimulate more criticism and, in turn, help to shift public opinion. Paradoxically, therefore, adjustments (âhasbara 2.0â) have underlined the image of Israel as a colonial power engaged in violent occupation
- âŠ