Analog property checkers: a DDR2 case study

The formal specification component of verification can be exported to simulation through the idea of property checkers. The essence of this approach is the automatic construction of an observer from the specification in the form of a program that can be interfaced with a simulator and alert the user if the property is violated by a simulation trace. Although not complete, this lighter approach to formal verification has been effectively used in software and digital hardware to detect errors. Recently, the idea of property checkers has been extended to analog and mixed-signal systems. In this paper, we apply the property-based checking methodology to an industrial and realistic example of a DDR2 memory interface. The properties describing the DDR2 analog behavior are expressed in the formal specification language stl/psl in form of assertions. The simulation traces generated from an actual DDR2 interface design are checked with respect to the stl/psl assertions using the amt tool. The focus of this paper is on the translation of the official (informal and descriptive) specification of two non-trivial DDR2 properties into stl/psl assertions. We study both the benefits and the current limits of such approac

BREAKOUT DIALOG ANALYSIS FOR WEB CONFERENCING APPLICATIONS

Video conferencing applications typically only allow one person to talk at a time. This is perfect for meetings that are presentations, but may not be acceptable for virtual social events (e.g., happy hours ) or brainstorming type meetings where, in the physical world, people naturally break off to have smaller, more intimate meetings to discuss a specific topic. Recent advancements to video conferencing applications have enabled users to create sub-meetings where smaller discussions can take place within a greater meeting. However, these sub-meetings restrict users to only seeing and hearing the participants within that sub-meeting without any context of the other discussions occurring at the same time. Techniques herein may provide for displaying a list of the top words being used in different sub-meetings, which can help users to determine the topics being discussed and decide which sub-meeting they may desire to join

PROXIMITY BASED MEETING DIAL-IN

A solution is provided that leverages a digital proximity-based mechanism to determine that a meeting is taking place and then to automatically trigger a notification (with a close group of colleagues) so that others may also join the meeting remotely

VISUAL FIDUCIALS FOR PRIVACY AND SECURITY

It can be difficult and time-consuming to maintain personal security and privacy while participating on-line video experiences. Many modifications can be provided post-production but this is unrealistic in the real-time world in which video/camera systems are often utilized. Presented herein is a technique for using a Quick Response (QR) code or other similar encoding mechanism within the field of view of a video/camera solution as a means to provide real-time/in-stream configuration of privacy and security zones. The encoding mechanism would contain all information necessary to define these zones. Once detected within the field of view, these zones would remain in effect until actively disabled

Real-time observation of epitaxial graphene domain reorientation.

Graphene films grown by vapour deposition tend to be polycrystalline due to the nucleation and growth of islands with different in-plane orientations. Here, using low-energy electron microscopy, we find that micron-sized graphene islands on Ir(111) rotate to a preferred orientation during thermal annealing. We observe three alignment mechanisms: the simultaneous growth of aligned domains and dissolution of rotated domains, that is, 'ripening'; domain boundary motion within islands; and continuous lattice rotation of entire domains. By measuring the relative growth velocity of domains during ripening, we estimate that the driving force for alignment is on the order of 0.1 meV per C atom and increases with rotation angle. A simple model of the orientation-dependent energy associated with the moiré corrugation of the graphene sheet due to local variations in the graphene-substrate interaction reproduces the results. This work suggests new strategies for improving the van der Waals epitaxy of 2D materials

Helium isotope variations in peridotite, gabbro and basalt from the Kane Oceanic Core Complex

The Kane Oceanic Core Complex (OCC) is a valuable window into crustal architecture and chemical composition of the lithosphere beneath a slow-spreading ocean ridge. A suite of > 30 samples (comprised of whole rocks, mineral separates and basalt glasses) has been analyzed for ³He/⁴He isotope ratios and He concentrations. Gas extraction experiments included crushing in vacuum, step heating and fusion in a high-vacuum furnace. We found ³He/⁴He in the two freshest peridotites (harzburgite and olivine websterite) to be identical to ratios measured in basalt glasses collected from the Kane fracture zone-ridge axis intersection (8.4–8.7 R[subscript A]). Notably, the freshest and least deformed peridotite (a porphyroclastic harzburgite) has the highest helium content of any of the OCC ultramafic rocks (170 ncc STP/g), while the majority of its helium (70%) is released only upon melting. Lower helium contents (1-45 ncc STP/g) and more variable ³He/⁴He (2.0-6.3 R[subscript A]) are found in other more altered/deformed peridotite samples (whole rocks, clinopyroxene and orthopyroxene separates). For example, three mylonitized peridotites have lower helium contents compared to the less deformed peridotites. Troctolite intrusions from the Adam and Eve Domes appear to record very late-stage melt impregnation fed through dunite conduits near the MOHO. ³He/⁴He in these troctolites overlaps with values in the fresh peridotites and axial basalts, but extends to slightly higher values (8.6-9.0 RA). Collectively, fresh Kane peridotites and troctolites having He concentrations above 10 ncc STP/g show ³He/⁴He ratios of 8.4-9.0 RA that are higher than the median value (8.0-8.2 R[subscript A]) for mid-ocean ridge basalts. This suggests that domains of depleted upper mantle in the Kane region tend to have ³He/⁴He ratios of 9 RA or higher, similar to what is observed in the most trace-element depleted MORBs globally. Kane gabbroic rocks are more variable in 3He/⁴He. A subset of gabbros show systematically lower ³He/4He ratios (0.9-7.2 R[subscript A]), with He concentrations of 1-24 ncc STP/g, reflecting the increased importance of atmospheric and radiogenic components in several cases. Nonetheless, two whole rock gabbroic samples plus an amphibole separate have ³He/⁴He ratios of 7.6-8.0 R[subscript A] and He contents between 13 and 57 ncc STP/g. Variation in the sampling of a lithologically heterogeneous mantle source by the partial melting process may account for the observed ³He/⁴He variability of 7.6-9.0 R[subscript A] in peridotite, gabbro and basalt in the Kane area

New Insights into Mantle Dynamics from Helium Isotopes and Argon Geochronology

Earth’s mantle extends to nearly 3000 km depth, comprises >80 % of Earth’s total volume, and has the largest influence on the primordial and radiogenic heat budget. Despite its importance, the structure and composition of the mantle is still debated. There are three primary models for Earth’s mantle structure that contain some degree of overlap. First, the Burke model invokes both small scale convection in the upper mantle coupled with larger scale, whole mantle convection. This model implies that long lived intraplate volcanic island chains are derived from upwelling plumes that originate near the edges of thermochemical piles in the lower mantle, while smaller and more ephemeral volcanic provinces originate from melting in the upper mantle. Second, the Courtillot model is similar to the Burke model, except multiple plume types exist, some originating from the core-mantle boundary and some separating from massive lower mantle upwellings that stall near the mantle transition zone at 400-660 km. Third, the Anderson model invokes upper and lower mantle isolation throughout Earth’s history, with volcanism originating through melting of a chemically heterogeneous upper mantle. The origin and evolution of intraplate volcanism are therefore central to understanding the dynamics and evolution of the mantle. In this dissertation, I present new constraints on Earth’s mantle using geochemical, geochronological and geodynamical investigations of intraplate volcanism in both continental and oceanic settings. The first study focuses on the origin of the enigmatic intraplate volcanic fields (harrats) of Saudi Arabia. Helium isotope compositions and trace element concentrations were determined for mantle xenoliths and lava flows from Harrat Hutaymah, plus ³He/⁴He in several xenoliths from Harrat Al Birk, Al Kishb, and Ithnayn. Harrat Hutaymah is the most northeastern Arabian volcanic field, found off of the main axis of Arabian volcanism, referred to as the Makkah-Medinah-Nafud (MMN) line. Hutaymah has uniform ³He/⁴He of 7.5 Rᴀ (where Rᴀ is the atmospheric ratio) in nearly all xenolith types. The uniformity is explained by volatile equilibration between the xenoliths and the host magma through the trapping of fluids/gases along grain defects during magma ascent, followed by re-annealing at lower pressure. Anhydrous spinel lherzolites from Hutaymah, Ithnanyn and Al Birk are notably different, having lower ³He/⁴He of 6.8 Rᴀ and distinctly depleted light rare earth element signatures. The widespread presence of this 6.8 Rᴀ signature in the lherzolites appears to be representative of the Arabian Proterozoic lithosphere prior to any metasomatic overprinting associated with later volcanic/tectonic activity. The origin of volcanism associated with the harrats located off the MMN line appears to involve mixing of delaminated, ancient enriched lithosphere with shallow depleted asthenosphere. Elevated ³He/⁴He signatures associated with a deep mantle plume origin are absent in the peripheral harrats, although they appear to be weakly present in some volcanic formations along the MMN line. The second study investigated intraplate volcanism in the Marquesas Islands, French Polynesia. This archipelago represents the surface expression of a low buoyancy flux mantle plume in a region of oceanic lithosphere marked by deep seated fracture zones. The Marquesas plume appears to contain an intrinsically large isotopic and chemical heterogeneity, both geographically and through time. The study uses ³He/⁴He results, major and trace element compositions of whole rocks, ⁴⁰Ar/³⁹Ar age determinations, and chemical analyses of olivine-hosted melt inclusions (OHMIs). The new results indicate that magmas feeding Marquesas volcanism are chemically diverse and are derived by melting of small-scale heterogeneities in the source regions. Variation in Cl/K among the OHMIs suggests that both the melting of recycled altered crust and interaction of magmas with brine at shallow levels potentially affects the lavas erupted in this region. Lavas at Hiva Oa show an increase in ³He/⁴He from shield (8.3 Rᴀ; 2.6 Ma) to late-shield stage (10.4-14.5 Rᴀ; 2.2 Ma), followed by a slight decrease (9.0-11.4 Rᴀ) during the post-shield phase (10 Rᴀ) are restricted to the central islands of Nuku Hiva and Hiva Oa in the Marquesas chain, suggesting a concentrically zoned mantle plume that has primitive and hot material concentrated near its central axis. The third study provides a refined history of the Rurutu hotspot, a long-lived mantle plume situated beneath the Pacific plate. Provided are new ⁴⁰Ar/³⁹Ar age determinations for seamounts from the Tuvalu Islands region of the west Pacific. These islands and seamounts range in age from 64 to 47 Ma and are isotopically similar to some young volcanoes in the Cook-Austral region. Using age constrained seamounts from the Rurutu chain (0-10 Ma; 47-72 Ma) in combination with the Pacific Louisville hotspot (0-79 Ma) and Hawaiian hotspot (0-78 Ma), the relative motions of these hotspots were computed. These motions confirm that Hawaii is unique, having an abrupt, southward plume drift from 60-47 Ma, while both Louisville and Rurutu show similar, eastward trending motions. Using geodynamic models of plume motions based primarily on seismic tomography and mantle viscosity models, the conditions required to account for the observed motions were tested. The relative motions are best reproduced when the plumes are both rooted near the core-mantle boundary and have roots that are able to move by mantle flow. However, none of the model parameters can properly reproduce the rapid motions of the Hawaiian hotspot, indicating additional processes may be responsible. The relative hotspot motions cannot be reproduced when the plumes are sourced at the upper/lower mantle boundary and thus indicate a deeper origin for long-lived plumes. The studies presented herein generally support the Burke model for mantle structure. The results from age-progressive Pacific intraplate volcanism support a plume source that is derived from dense thermochemical piles in the lower mantle. These source regions have somewhat mobile edges and contain a component of primitive material. Geochemical results for the Arabian volcanic fields indicate that secondary convection in the upper mantle may generate melts near the lithosphere-asthenosphere boundary, and therefore also be a cause of intraplate volcanism

Analog Property Checkers: A Ddr2 Case Study

The formal specification component of verification can be exported to simulation through the idea of property checkers. The essence of this approach is the automatic construction of an observer from the specification in the form of a program that can be interfaced with a simulator and alert the user if the property is violated by a simulation trace. Although not complete, this lighter approach to formal verification has been effectively used in software and digital hardware to detect errors. Recently, the idea of property checkers has been extended to analog and mixed-signal systems. In this paper, we apply the property-based checking methodology to an industrial and realistic example of a DDR2 memory interface. The properties describing the DDR2 analog behavior are expressed in the formal specification language stl/psl in form of assertions. The simulation traces generated from an actual DDR2 interface design are checked with respect to the stl/psl assertions using the amt tool. The focus of this paper is on the translation of the official (informal and descriptive) specification of two non-trivial DDR2 properties into stl/psl assertions. We study both the benefits and the current limits of such approach

GazeGPT: Augmenting Human Capabilities using Gaze-contingent Contextual AI for Smart Eyewear

Multimodal large language models (LMMs) excel in world knowledge and problem-solving abilities. Through the use of a world-facing camera and contextual AI, emerging smart accessories aim to provide a seamless interface between humans and LMMs. Yet, these wearable computing systems lack an understanding of the user's attention. We introduce GazeGPT as a new user interaction paradigm for contextual AI. GazeGPT uses eye tracking to help the LMM understand which object in the world-facing camera view a user is paying attention to. Using extensive user evaluations, we show that this gaze-contingent mechanism is a faster and more accurate pointing mechanism than alternatives; that it augments human capabilities by significantly improving their accuracy in a dog-breed classification task; and that it is consistently ranked as more natural than head- or body-driven selection mechanisms for contextual AI. Moreover, we prototype a variety of application scenarios that suggest GazeGPT could be of significant value to users as part of future AI-driven personal assistants.Comment: Project video: https://youtu.be/AuDFHHTK_m