Verifying Reliability Properties Using the Hyperball Abstract Domain

The 3D thermal convection in the Boussinesq approximation with heating from below and dynamo in the cube are considered. We study dependence of the convection intensity and magnetic field generation on the latitude in $\beta$-plane approximation. It is shown that kinetic energy gradually increases from the poles to the equator more than order of magnitude. The model predicts the strong azimuthal thermal wind, which direction depends on the sign of the thermal convective fluctuations. The spatial scale of the arising flow is comparable to the scale of the physical domain. The magnetic energy increases as well, however dynamo efficiency, i.e., the ratio of the magnetic energy to the kinetic one decreases to the equator. This effect can explain predominance of the dipole configuration of the magnetic field observed in the planets and stars. The approach is useful for modeling of the magnetohydrodynamic turbulence in planetary cores and stellar convective zones.

The proposed homogenization methodology applies to periodic electromagnetic structures (photonic crystals and metamaterials), treated on two main spatial scales in the frequency domain. Fields on the fine scale are approximated via a set of Bloch modes, with a respective set of generalized plane waves on the coarse scale. From this general setup, one derives a hierarchy of models, from quasi-static to nonlocal, with various trade-offs between accuracy, applicability to various illumination conditions, and simplicity. Nonlocal models can improve the accuracy of homogenization by an order of magnitude.

The article presents experience in using the concrete Teamcenter - Variation Analysis system application to assess the accuracy of mechanical assemblies. When creating a geometric model of the product to be designed, modern CAD systems show the nominal geometry of a displayed part or mounting assembly with all the necessary annotations. It is natural that all necessary tolerances for linear and angular dimensions and also shape and location tolerances are assigned. But as a result of the statistical variation of the assigned tolerances, there are situations when individual parts, being classified as fit, are not assembled, or assembly defects are found just in the course of operation or repair of the finished product.Of all tolerances assigned at the design stage, it is necessary to emphasize the tolerances in face flatness, squareness, and parallelism and other tolerances of shape and location. The fact is that these tolerances ultimately determine the accuracy of an assembled product. Indeed, if the mating-in-the-assembly flat faces turn out to be insufficiently flat, this misalignment “brings to nought” all the efforts to achieve high accuracy of the parts to be joined. Repeated tests have shown that when assessing the individual contributions to a total error, the assembly inaccuracies turn out to be an order of magnitude more significant than errors in manufacturing of individual parts. The described Variation Analysis application is used to assess assembling inaccuracies.When analysing the individual parts, the described application can be effectively used to calculate dimension chains (direct and inverse problem). As is customary in many modern CAT systems, the Variation Analysis application takes into account the statistical variation of all the tolerances described. The user has to set the law of probability density distribution for all assigned tolerances in the intermediate items of the dimensional chain, and to perform a numerical experiment to simulate the entire parent population of random events. As a result, the obtained probability density distribution curve has a magnitude we are interested in, taking into account the statistical variation of tolerances in the intermediate items and the errors that occur during the product assembly. Moreover, the user can also have a certain protocol in which the system gives information on contribution that one or another assigned tolerance makes to the total error. This allows making efficacious corrections to the tolerances in order to obtain useful results.

The freshwater reservoir effect is a potential problem when radiocarbon dating fish bones, shells, human bones, or food crusts on pottery from sites near rivers or lakes. The reservoir age in hardwater rivers can be up to several thousand years and may be highly variable. Accurate 14C dating of freshwater-based samples requires knowing the order of magnitude of the reservoir effect and its degree of variability. Measurements on modern riverine materials may not give a single reservoir age correction that can be applied to archaeological samples, but they show the order of magnitude and variability that can also be expected for the past. This knowledge will be applied to the dating of food crusts on pottery from the Mesolithic sites Kayhude at the Alster River and Schlamersdorf at the Trave River, both in Schleswig-Holstein, northern Germany.

A new three-scale model to describe the coupling between pH-dependent flows and transient ion transport including sorption phenomena in kaolinite clays is proposed. The kaolinite is characterized by three separate nano-micro and macroscopic length scales. The (micro)-scale consists of micro-pores saturated by an aqueous solution containing four monovalent ionic species (Na+, H+, Cl−, OH−) and charged solid particles surrounded by thin electrical double layers. The movement of the ions is governed by the Nernst-Planck equations and the influence of the double layers upon the flow is dictated by the Helmholtz–Smoluchowski slip boundary condition in the tangential velocity. In addition, sorption interface conditions for ion transport are postulated in the sense of Auriault and Lewandowska (Eur. J. Mech. A 15:681–704, 1996) to capture the immobilization of the ions in the electrical double layer and on particle surface due to protonation/deprotonation reactions. The intensity of sorption relative to diffusion effects is quantified by the Damkohler number, whose order of magnitude is estimated by invoking the nanoscopic modeling of the thin EDL based on Poisson–Boltzmann problem for the local electric potential coupled with a non-linear surface charge density with constitutive law dictated by the protonation/deprotonation reactions. The two-scale nano/micro model including sorption and slip boundary condition is homogenized to the core scale leading to a derivation of macroscopic governing equations.

A new concept is presented in this paper of quasi-dynamic cell formation for the design of a cellular manufacturing system, based on analysing the fact that static and dynamic cell formation could not reflect the real situation of a modern cellular manufacturing system. Further, workforce resources are integrated into quasi-dynamic cell formation and thus a quasi-dynamic dual-resource cell-formation problem is proposed. For solving this problem, this paper first establishes a non-linear mixed integer programming model, where inter-cell and intra-cell material cost, machine relocation cost, worker operation time, loss in batch quality and worker salary are to be minimised. Then, a multi-objective GA is developed to solve this model. Finally, a real life case study is conducted to validate the proposed model and algorithm. The actual operation results show that the case enterprise significantly decreases its material handling cost and workforce number and obviously increases its product quality after carrying out the obtained scheme.

The modern VLSI systems that demand high reliability require carefully-designed power/ground network to provide stable power supply. Though the power supply connection is verified before tapeout, it is quite difficult to evaluate its actual quality and reliability after fabrication. This paper proposes a novel way to evaluate the power supply network based on the measurement of magnetic field emission from LSI. The proposed method estimates the actual current flow from the magnetic field measurement results, and enables us to find defects or design faults such as VIA/wire disconnections and/or current concentration with low cost. Experimental result using an electromagnetic field simulator demonstrate that the proposed method precisely estimates the current flow in the supply network and clearly indicates the VIA fault location. To verify the feasibility of the proposed method with actual measurement results, the test structure is designed and fabricated in 0.18 μm 1P5M CMOS process.

The verifiable encryption of bits is the main computational step that is needed to prepare ballots in many practical voting protocols. Its computational load can also be a practical bottleneck, preventing the deployment of some protocols or requiring the use of computing clusters.We investigate the question of producing many verifiably encrypted bits in an efficient and portable way, using as a baseline the protocol that is in use in essentially all modern voting systems and libraries supporting homomorphic voting, including ElectionGuard, a state-of-the-art open source voting SDK deployed in government elections. Combining fixed base exponentiation techniques and new encryption and ZK proof mechanisms, we obtain speed-ups by more than one order of magnitude against standard implementations. Our exploration requires balancing conflicting optimization strategies, and the use of asymptotically less efficient protocols that turn out to be very effective in practice. Several of our proposed improvements are now on the ElectionGuard roadmap.

Hydrolysis of Aspirin Studied by Spectrophotometric and Fluorometric Variable-Temperature Kinetics

Analytics on modern data analytic and data warehouse systems often need to run large complex queries on increasingly complex database schemas. A lot of progress has been made on executing such complex queries using techniques like scale out query processing, hardware accelerators like GPUs and code generation techniques. However, optimization of such queries remains a challenge. Existing optimal solutions either cannot be effectively parallelized, or are inefficient while doing a lot of unnecessary work. In this demonstration, we present our system, GPU-QO, which aims to demonstrate query optimization techniques for large analytical queries using GPUs. We first demonstrate Massively Parallel Dynamic Programming (MPDP) – a novel query optimization technique that can run on GPUs to generate optimal plans in a (massively) parallel and efficient manner. We then showcase IDP2-MPDP and UnionDP – two heuristic techniques, again using GPUs, that can even optimize queries containing 1000s of joins. Furthermore, we compare our techniques with current state-of-the-art solutions, and demonstrate how our techniques can reduce optimization time for optimal solutions by nearly two orders of magnitude and produce much better query plans for heuristics (up to 7x).

The dynamics of modern hybrid power systems are characterized by behaviors at different timescales, typically separated by several orders of magnitude. In this paper we apply the envelope-following method to hybrid power systems simulations, in which single-phase and three-phase representations of a power system co-occur. This simulation method is well suited for handling coexisting behaviors occurring at different timescales. Compared to the simulation approaches present in the literature, the envelope-following method does not need to continuously switch between two separate simulation engines, but rather automatically handles instantaneous variations in the dynamics of the system, such as faults or topology changes. Additionally, given the vast penetration of power electronic components in modern electricity networks, employing the envelope-following method allows using a vast array of numerical algorithms that have been developed over the years to simulate electrical and electronic circuits. The proposed approach is validated by means of power systems case studies of increasing complexity.

Low-complexity and high-performance low-density parity-check (LDPC) decoders are highly demanded in various modern communication and storage systems. In this paper, a novel hard-decision decoding algorithm, called tabu-list random-penalty gradient descent bit-flipping (TRGDBF) algorithm, is proposed. Compared to the state-of-the-art hard-decision algorithms, the TRGDBF algorithm has much better error-correction performance due to several algorithmic improvements. First, a random-penalty term is introduced to the inversion function to help the decoder escape from trapping sets, which are the main causes of the error-floor phenomenon. Second, a tabu-list is employed to improve the decoding efficiency. Numerical results show that the TRGDBF algorithm can achieve up to two orders of magnitude better error-correction performance than the probabilistic gradient descent bit-flipping (PGDBF) algorithm and reduce the average iteration count by about 15%. In addition, a well-optimized hardware architecture is developed to implement the TRGDBF algorithm. Algorithmic transformation and architecture optimization are well explored to reduce the hardware complexity and latency. Synthesis results show that the TRGDBF decoder can work at a higher frequency and offer a larger throughput than the PGDBF decoder.

The installation of phasor measurement units (PMUs) in the power grids is mainly focused on the transmission systems. Researchers are continuously working on the PMUs for its installation in the transmission system. But, now due to the advancement in distribution system, i.e., for smart distribution system, a device is going to be installed which creates real-time synchrophasor data from the consumer voltage level, called μPMUs, which could provide new insight into modern power systems. These units can be created more cheaply, an order of magnitude less, than current commercial PMUs. For this reason, many more μPMUs could be deployed and provide a much higher resolution of the distribution grid. So, in this paper, the concepts like why we need micro-PMUs and its block diagram are explained. This paper also discusses the applications for synchrophasor technology in distribution systems.

A commercial pulsed-IV system is used to test a GaN HEMT with the purpose of extracting exponential time constants used for dynamic electro-thermal and charge-carrier trapping models. The time constants of these different physical phenomena can not only vary by many orders of magnitude, but also have regions of overlap. Self-heating and trapping are common phenomena affecting GaN HEMTs, thus characterization and understanding these dynamics is critical for developing accurate compact models. We investigated the approach of recording the drain current transient response under a careful selection of the bias conditions, to approximately separate the two phenomena to derive useful estimate of the different associated time constants. Modeling of these time constants is of concern for modulated signal processing, where they fall within typical bandwidths of modern communication systems.

Soft errors are one-time events that corrupt the state of a computing system but not its overall functionality. Large supercomputers are especially susceptible to soft errors because of their large number of components. Soft errors can generally be detected offline through the comparison of the final computation results of two duplicated computations, but this approach often introduces significant overhead. This paper presents Online-ABFT, a simple but efficient online soft error detection technique that can detect soft errors in the widely used Krylov subspace iterative methods in the middle of the program execution so that the computation efficiency can be improved through the termination of the corrupted computation in a timely manner soon after a soft error occurs. Based on a simple verification of orthogonality and residual, Online-ABFT is easy to implement and highly efficient. Experimental results demonstrate that, when this online error detection approach is used together with checkpointing, it improves the time to obtain correct results by up to several orders of magnitude over the traditional offline approach.