Miracle-dz/UniFAR-FTUs huggingface dataset:
Prediction of hot zone-center optical phonons in laser-irradiated molybdenum disulfide with a semiconductor multitemperature model

Previous multitemperature model (MTM) resolving phonon temperatures at the polarization level and measurements have uncovered remarkable nonequilibrium among different phonon polarizations in laser irradiated graphene and metals. Here, we develop a semiconductor-specific MTM (SC-MTM) by including electron-hole pair generation, diffusion, and recombination, and show that a phonon polarization-level model does not yield observable polarization-based nonequilibrium in laser-irradiated molybdenum disulfide (MoS$_2$). In contrast, appreciable nonequilibrium is predicted between zone-center optical phonons and the other modes. The momentum-based nonequilibrium ratio is found to increase with decreasing laser spot size and interaction with a substrate. This finding is relevant to the understanding of the energy relaxation process in two-dimensional optoelectronic devices and Raman measurements of thermal transport.
Violet: Architecturally Exposed Orchestration, Movement, and Placement for Generalized Deep Learning

Deep learning and hardware for it has garnered immense academic and industry interest in the past 5 years, with many novel proposals. However, the state-of-art remains NVIDIA’s TensorCore-based systems that provide top-of-line performance and coverage across a wide-spectrum of deep learning applications. In this paper, we ﬁrst identify four key problems any new DL solution must solve: 1) Data orchestration, 2) Data movement, 3) Work placement and blending these to achieve 4) Coverage across different types of DL applications. With this as a guide, we propose Violet, a novel architecture with roots in multicore SIMD which balances the responsibilities for these four problems between the architecture, microarchitecture and software stack. Compared to the NVIDIA A100 GPU, we ﬁnd Violet achieves geo-mean 2.4X/10.6X and 2.1X/9.5X performance/efﬁciency for inference and training across the MLPerf benchmark suite. We present detailed operator-level analysis of the MLPerf benchmark suite, extracting out key behaviors – with implications for architecture research beyond this paper, that underpin the speedup and efﬁciency. Overall, this paper motivates the im-portance of balance, that the break down of responsibilities must be thought through carefully in order to compete with incumbent architecture designs.
Sound Scattering of a Plane Wave from a Nonabsorbing Sphere

Sound scattering from a sphere of arbitrary size is treated theoretically when the acoustic properties of the sphere are near those of the surrounding medium. Closed form analytic expressions are found for the reflectivity and total cross section. These expressions become exact only in the limit as the ratio of the densities and ratio of the speeds approach unity, but it is shown that for ratios as large as 5/4 and probably as large as 3/2 the approximate reflectivity and total cross section compare favorably with results of exact calculation. Calculations of reflectivity and total cross section, which would require weeks if made from the exact solution of the wave equation, may be completed in a few hours using the approximate closed form expressions.
On wavelet methods for estimating smooth functions

Without assuming any prior knowledge of wavelet methods, we develop theory describing their performance as estimators of smooth functions. The linear part of the wavelet estimator is discussed by analogy with classical kernel methods. Concise formulae are developed for its bias, variance and mean square error. These quantities oscillate somewhat erratically on a wavelength that is equivalent to the bandwidth, reflecting the irregular numerical fluctuations that are observed in practice. Nevertheless, the contributions of these oscillations to mean integrated square error tend to dampen one another out, even over very small intervals, with the result that mean integrated square error properties of linear wavelet methods are much closer to those of kernel methods than is perhaps reasonable, given the local behaviour. We illustrate the adaptive qualities of the nonlinear component of a wavelet estimator by describing its performance when the target function is smooth but has high-frequency oscillations. It is shown that the nonlinear component automatically adapts to changing local conditions, to the extent of achieving (except for a logarithmic factor) the same convergence rate as the optimal linear estimator, but without a need to adjust the underlying bandwidth. This makes explicitly clear the way in which the linear part of the estimator takes care of the 'average' characteristics of the unknown curve, while the nonlinear part corrects for more erratic fluctuations, in a manner which is virtually independent of the construction of the linear part.
Classes of Strongly Stabilizing Bandpass Controllers for Flexible Structures

This paper proposes different design strategies of robust controllers for high-order plants. The design is tailored on the structure of the equations resulting from modeling flexible structures by using modal coordinates. Moreover, the control laws have some characteristics which make them specially suited for active vibration reduction, such as strong stabilization property and bandpass frequency shape. The approach is also targeted the case of more sensors than actuators, which is very frequent in practical applications. Indeed, actuators are often rather heavy and bulky, while small and light sensors may be placed more freely. In such cases, sensors can be usefully placed in the locations where the primary force fields act on the structure, so as to provide the controller with a direct information on the disturbance effects in terms of structural vibrations. Eventually, this approach may lead to uncolocated control strategies. The design problem is here solved by resorting to a Linear Matrix Inequality technique, which allows also to select the performance weights based on different design requirements, for example, a suitable bandpass frequency shape. Experimental results are presented for a vibration reduction problem of a stiffened aeronautical panel controlled by piezoelectric actuators.
Discovery, implications and initial use of semi-synthetic organisms with an expanded genetic alphabet/code

Much recent interest has focused on developing proteins for human use, such as in medicine. However, natural proteins are made up of only a limited number of canonical amino acids with limited functionalities, and this makes the discovery of variants with some functions difficult. The ability to recombinantly express proteins containing non-canonical amino acids (ncAAs) with properties selected to impart the protein with desired properties is expected to dramatically improve the discovery of proteins with different functions. Perhaps the most straightforward approach to such an expansion of the genetic code is through expansion of the genetic alphabet, so that new codon/anticodon pairs can be created to assign to ncAAs. In this review, I briefly summarize more than 20 years of effort leading ultimately to the discovery of synthetic nucleotides that pair to form an unnatural base pair, which when incorporated into DNA, is stably maintained, transcribed and used to translate proteins in Escherichia coli. In addition to discussing wide ranging conceptual implications, I also describe ongoing efforts at the pharmaceutical company Sanofi to employ the resulting ‘semi-synthetic organisms' or SSOs, for the production of next-generation protein therapeutics. This article is part of the theme issue ‘Reactivity and mechanism in chemical and synthetic biology’.
Capturing the free energy of transition state stabilization: insights from the inhibition of mandelate racemase

Mandelate racemase (MR) catalyses the Mg2+-dependent interconversion of (R)- and (S)-mandelate. To effect catalysis, MR stabilizes the altered substrate in the transition state (TS) by approximately 26 kcal mol–1 (–ΔGtx), such that the upper limit of the virtual dissociation constant of the enzyme-TS complex is 2 × 10–19 M. Designing TS analogue inhibitors that capture a significant amount of ΔGtx for binding presents a challenge since there are a limited number of protein binding determinants that interact with the substrate and the structural simplicity of mandelate constrains the number of possible isostructural variations. Indeed, current intermediate/TS analogue inhibitors of MR capture less than or equal to 30% of ΔGtx because they fail to fully capitalize on electrostatic interactions with the metal ion, and the strength and number of all available electrostatic and H-bond interactions with binding determinants present at the TS. Surprisingly, phenylboronic acid (PBA), 2-formyl-PBA, and para-chloro-PBA capture 31–38% of ΔGtx. The boronic acid group interacts with the Mg2+ ion and multiple binding determinants that effect TS stabilization. Inhibitors capable of forming multiple interactions can exploit the cooperative interactions that contribute to optimum binding of the TS. Hence, maximizing interactions with multiple binding determinants is integral to effective TS analogue inhibitor design. This article is part of the theme issue ‘Reactivity and mechanism in chemical and synthetic biology’.
Outcomes after Anterior Interosseous Nerve to Ulnar Motor Nerve Transfer

Abstract Background Ulnar nerve lesions proximal to the elbow can result in loss of intrinsic muscle function of the hand. The anterior interosseous nerve (AIN) to deep motor branch of the ulnar nerve (DBUN) transfer has been demonstrated to provide intrinsic muscle reinnervation, thereby preventing clawing and improving pinch and grip strength. The purpose of this study was to evaluate the efficacy of the AIN to DBUN transfer in restoring intrinsic muscle function for patients with traumatic ulnar nerve lesions. Methods We performed a prospective, multi-institutional study of outcomes following AIN to DBUN transfer for high ulnar nerve injuries. Twelve patients were identified, nine of which were enrolled in the study. The mean time from injury to surgery was 15 weeks. Results At final follow-up (mean postoperative follow-up 18 months + 15.5), clawing was observed in all nine patients with metacarpophalangeal joint hyperextension of the ring finger averaging 8.9 degrees (+ 10.8) and small finger averaging 14.6 degrees (+ 12.5). Grip strength of the affected hand was 27% of the unaffected extremity. Pinch strength of the affected hand was 29% of the unaffected extremity. None of our patients experienced claw prevention after either end-to-end ( n = 4) or end-to-side ( n = 5) AIN to DBUN transfer. Conclusion We conclude that, in traumatic high ulnar nerve injuries, the AIN to DBUN transfer does not provide adequate intrinsic muscle reinnervation to prevent clawing and normalize grip and pinch strength.
Theory of metal‐insulator‐semiconductor solar cells

Recent reports in the literature indicate that the introduction of an interfacial oxide layer in a Schottky barrier can greatly increase the photovoltaic conversion efficiency of such devices. We propose an explanation for the operation of such solar cells based on the concept that they are minority‐carrier nonequilibrium MIS tunnel diodes. Calculations of efficiency as a function of insulator thickness, substrate carrier concentration, surfaces states, and oxide charge are presented. These indicate that a maximum theoretical efficiency of 21% is possible under AM2 illumination for high substrate doping and low interface defect density.
Two-scale solution for tripped turbulent boundary layer

Abstract Recent findings on the Reynolds-number-dependent behaviour of near-wall turbulence in terms of the ‘foot-printing’ of outer large-scale structures call for a new modelling development. A two-scale framework was proposed to couple a local fine-mesh solution with a global coarse-mesh solution by He (Intl J. Numer. Meth. Fluids, vol. 86, 2018, pp. 655–677). The methodology was implemented and demonstrated by Chen & He (J. Fluid Mech, vol. 933, 2022, p. A47) for a canonical turbulent channel flow, where the mesh-count scaling with Reynolds number is potentially reduced from $O(R{e^2})$ for a conventional wall-resolved large-eddy simulation (WRLES) to $O(R{e^1})$. The present work extends the two-scale method to turbulent boundary layers. A two-dimensional roughness element is used to trip a turbulent boundary layer. It is observed that large-scale disturbances originating at the trip have a much shorter lifetime and weaker foot-printing signatures on near-wall flow compared to those long streaky coherent structures in well-developed wall-bounded turbulent flows. Modal analyses show that the impact of trip-induced large scales can be adequately captured by a locally embedded fine-mesh block. For the tripped turbulent boundary layer, a Chebyshev block-spectral mapping is adopted to propagate source terms from the local fine-mesh blocks to the global coarse-mesh domain, driving to a target solution for the upscaled equations. The computed mean statistics and energy spectra are in good agreement with corresponding experimental data, WRLES and direct numerical simulation (DNS) results. The overall mesh count–$Re$ scaling is estimated to reduce from $O(R{e^{1.8}})$ for the full wall-resolved LES to $O(R{e^{0.9}})$ for the present two-scale solution.
Strain self-amplification is larger than vortex stretching due to an invariant relation of filtered velocity gradients

Abstract A relation among invariants of filtered velocity gradients with two different filter sizes is derived. Based on this relation and physical reasoning, it is shown analytically that strain self-amplification contributes more to energy transfer than vortex stretching in homogeneous turbulence, as observed in recent numerical investigations of homogeneous isotropic turbulence. We note that the invariant relation studied and hence the inequality between strain self-amplification and vortex stretching apply to all homogeneous flows, not restricted to isotropic turbulence.
C-Cube

Recent innovations significantly advance the communication capabilities of backscatter networks, while energy harvesting remains the bottleneck of these backscatters. To tackle this problem, existing studies explore distributed beamforming techniques to beam enhanced energy for a battery-free tag. However, they cannot concurrently transfer high-density power to multiple tags since the system is unable to estimate accurate channel state information (CSI). In this paper, we argue that by deploying a lightweight beamforming helper, we can push the limit of CSI estimation with negligible overhead on the tag. The big gap between the wireless charging threshold and the CSI estimation sensitivity can provide stable estimation result of CSI for the charging system even the signal experiences double fading. On this basis, we propose C-Cube, a concurrent charging system for backscatter networks. C-Cube employs distributed beamforming with the help of CSI to indicate the phase alignment process. To bring it into practice, we design a cold start scheme to activate tags by transmitting a distributed orthogonal frequency (DOF) signal. Moreover, to ensure all tags' CSIs have been successfully received, a spatial-based CSI classifier is explored in C-Cube. We further align the beamforming phase to optimize a novel metric called relative power, instead of the received power metric. The new metric can eliminate the impact of the unknown tag-to-helper channel. We implement our system with USRP/GNURadio platform and customized tags in a real environment. C-Cube can achieve the same coverage as the state-of-the-art and reduce the charge time by 44.1% and 30.2%.
Making a Type Difference: Subtraction on Intersection Types as Generalized Record Operations

In programming languages with records, objects, or traits, it is common to have operators that allow dropping, updating or renaming some components. These operators are useful for programmers to explicitly deal with conflicts and override or update some components. While such operators have been studied for record types, little work has been done to generalize and study their theory for other types. This paper shows that, given subtyping and disjointness relations, we can specify and derive algorithmic implementations for a general type difference operator that works for other types, including function types, record types and intersection types. When defined in this way, the type difference algebra has many desired properties that are expected from a subtraction operator. Together with a generic merge operator, using type difference we can generalize many operations on records formalized in the literature. To illustrate the usefulness of type difference we create an intermediate calculus with a rich set of operators on expressions of arbitrary type, and demonstrate applications of these operators in CP, a prototype language for Compositional Programming. The semantics of the calculus is given by elaborating into a calculus with disjoint intersection types and a merge operator. We have implemented type difference and all the operators in the CP language. Moreover, all the calculi and related proofs are mechanically formalized in the Coq theorem prover.
Helping Users Debug Trigger-Action Programs

Trigger-action programming (TAP) empowers a wide array of users to automate Internet of Things (IoT) devices. However, it can be challenging for users to create completely correct trigger-action programs (TAPs) on the first try, necessitating debugging. While TAP has received substantial research attention, TAP debugging has not. In this paper, we present the first empirical study of users' end-to-end TAP debugging process, focusing on obstacles users face in debugging TAPs and how well users ultimately fix incorrect automations. To enable this study, we added TAP capabilities to an existing 3-D smart home simulator. Thirty remote participants spent a total of 84 hours debugging TAPs using this simulator. Without additional support, participants were often unable to fix buggy TAPs due to a series of obstacles we document. However, we also found that two novel tools we developed helped participants overcome many of these obstacles and more successfully debug TAPs. These tools collect either implicit or explicit feedback from users about automations that should or should not have happened in the past, using a SAT-solving-based algorithm we developed to automatically modify the TAPs to account for this feedback.
A Partial Order View of Message-Passing Communication Models

There is a wide variety of message-passing communication models, ranging from synchronous "rendez-vous" communications to fully asynchronous/out-of-order communications. For large-scale distributed systems, the communication model is determined by the transport layer of the network, and a few classes of orders of message delivery (FIFO, causally ordered) have been identified in the early days of distributed computing. For local-scale message-passing applications, e.g., running on a single machine, the communication model may be determined by the actual implementation of message buffers and by how FIFO queues are used. While large-scale communication models, such as causal ordering, are defined by logical axioms, local-scale models are often defined by an operational semantics. In this work, we connect these two approaches, and we present a unified hierarchy of communication models encompassing both large-scale and local-scale models, based on their concurrent behaviors. We also show that all the communication models we consider can be axiomatized in the monadic second order logic, and may therefore benefit from several bounded verification techniques based on bounded special treewidth.
Single-Source-Single-Target Interleaved-Dyck Reachability via Integer Linear Programming

An interleaved-Dyck (InterDyck) language consists of the interleaving of two or more Dyck languages, where each Dyck language represents a set of strings of balanced parentheses.InterDyck-reachability is a fundamental framework for program analyzers that simultaneously track multiple properly-matched pairs of actions such as call/return, lock/unlock, or write-data/read-data.Existing InterDyck-reachability algorithms are based on the well-known tabulation technique. This paper presents a new perspective on solving InterDyck-reachability. Our key observation is that for the single-source-single-target InterDyck-reachability variant, it is feasible to summarize all paths from the source node to the target node based on path expressions. Therefore, InterDyck-reachability becomes an InterDyck-path-recognition problem over path expressions. Instead of computing summary edges as in traditional tabulation algorithms, this new perspective enables us to express InterDyck-reachability as a parenthesis-counting problem, which can be naturally formulated via integer linear programming (ILP). We implemented our ILP-based algorithm and performed extensive evaluations based on two client analyses (a reachability analysis for concurrent programs and a taint analysis). In particular, we evaluated our algorithm against two types of algorithms: (1) the general all-pairs InterDyck-reachability algorithms based on linear conjunctive language (LCL) reachability and synchronized pushdown system (SPDS) reachability, and (2) two domain-specific algorithms for both client analyses. The experimental results are encouraging. Our algorithm achieves 1.42×, 28.24×, and 11.76× speedup for the concurrency-analysis benchmarks compared to all-pair LCL-reachability, SPDS-reachability, and domain-specific tools, respectively; 1.2×, 69.9×, and 0.98× speedup for the taint-analysis benchmarks. Moreover, the algorithm also provides precision improvements, particularly for taint analysis, where it achieves 4.55%, 11.1%, and 6.8% improvement, respectively.
Grisette: Symbolic Compilation as a Functional Programming Library

The development of constraint solvers simplified automated reasoning about programs and shifted the engineering burden to implementing symbolic compilation tools that translate programs into efficiently solvable constraints. We describe Grisette, a reusable symbolic evaluation framework for implementing domain-specific symbolic compilers. Grisette evaluates all execution paths and merges their states into a normal form that avoids making guards mutually exclusive. This ordered-guards representation reduces the constraint size 5-fold and the solving time more than 2-fold. Grisette is designed entirely as a library, which sidesteps the complications of lifting the host language into the symbolic domain. Grisette is purely functional, enabling memoization of symbolic compilation as well as monadic integration with host libraries. Grisette is statically typed, which allows catching programming errors at compile time rather than delaying their detection to the constraint solver. We implemented Grisette in Haskell and evaluated it on benchmarks that stress both the symbolic evaluation and constraint solving.