48 research outputs found
Tactics for Reasoning modulo AC in Coq
We present a set of tools for rewriting modulo associativity and
commutativity (AC) in Coq, solving a long-standing practical problem. We use
two building blocks: first, an extensible reflexive decision procedure for
equality modulo AC; second, an OCaml plug-in for pattern matching modulo AC. We
handle associative only operations, neutral elements, uninterpreted function
symbols, and user-defined equivalence relations. By relying on type-classes for
the reification phase, we can infer these properties automatically, so that
end-users do not need to specify which operation is A or AC, or which constant
is a neutral element.Comment: 16
Tuning-Range Extension Strategies for Varactor-Based Frequency-Reconfigurable Antennas
OnlinePublTuning range extension strategies for varactor-based frequency-reconfigurable planar patch antennas are presented. The three tuning range optimization methods described in the paper include cooptimization of antenna dimensions and varactor properties, exploitation of multiple radiation modes, and reduction of parasitic capacitance. The first two strategies are emphasized by briefly reviewing two previously reported wide tuning range frequency-agile planar antennas. Importantly, the influence of parasitic capacitance on reducing the tuning range of the varactor-based frequency-reconfigurable antennas is then demonstrated by examining two antennas. The three tuning range extension methods are then combined to further expand the frequency tuning range of a reported frequency-reconfigurable antenna. The antenna has been re-designed, fabricated and experimentally characterized to demonstrate enhanced performance, which validates the proposed techniques, and their simultaneous application to reconfigurable antenna designs.Quoc Hung Dang, Nghia Nguyen-Trong, Christophe Fumeaux, Shengjian Jammy Che
Prevalence of Antibodies against Avian Influenza A (H5N1) Virus among Cullers and Poultry Workers in Ho Chi Minh City, 2005
Vortex structure in d-density wave scenario of pseudogap
We investigate the vortex structure assuming the d-density wave scenario of
the pseudogap. We discuss the profiles of the order parameters in the vicinity
of the vortex, effective vortex charge and the local density of states. We find
a pronounced modification of these quantities when compared to a purely
superconducting case. Results have been obtained for a clean system as well as
in the presence of a nonmagnetic impurity. We show that the competition between
superconductivity and the density wave may explain some experimental data
recently obtained for high-temperature superconductors. In particular, we show
that the d-density wave scenario explains the asymmetry of the gap observed in
the vicinity of the vortex core.Comment: 8 pages, 10 figure
Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network
Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism
PRINCIPLES OF COMPENSATION FOR HARM CAUSED BY A SOURCE OF INCREASED DANGER UNDER CIVIL LAW OF VIETNAM
Agent-based simulation for production planning and control in consideration of disruption events
An agent-based simulation (ABS) as a computer supported decision-making tool is presented for planning and evaluating job shop production. The presented approach focuses on short-term production planning and control. It allows planners to design and modify their models by describing all activities of workers and machines regarding operations related to the manufacturing process and tasks aided in the production. The simulated model was used for analyzing different operation modes and control strategies dealing with disruption events including machine breakdown, worker absence, and product defect. This provides an easy-to-implement simulation result through a description of coordinated actions and interactions of system resources. A case study for a remanufacturing job-shop shows effects of disruption events and reaction plans on the system performances
Developing the competence of organizing experiential activities for pre-service teachers – The case in Vietnam
Investing on human capital via enhancement of educational quality as one of the important factors to promote economic development all over the world. Basically, it is important to enhance pre-service teachers of primary education with necessary professional competences to implement teaching activities at primary schools. Based on relevant research on experiential activities, professional competence development for pre-service teachers of primary education and the general education curriculum in the case of Vietnam, the article develops a competency framework for organizing experiential learning activities for pre-service teachers of primary education in the context of education curriculum innovation; and simultaneously suggested fundamental solutions to improve pre-service teachers’ competence in organizing experiential activities. To achieve these above-mentioned goals, some research methods are used by the researchers including document analysis, pedagogical observation, and educational experience summarizing method
Impedance control of a hydraulically actuated robotic excavator
In robotic excavation, hybrid position/force control has been proposed for bucket digging trajectory following. In hybrid position/force control, the control mode is required to switch between position- and force-control depending on whether the bucket is in free space or in contact with the soil during the process. Alternatively, impedance control can be applied such that one control mode is employed in both free and constrained motion. This paper presents a robust sliding controller that implements impedance control for a backhoe excavator. The control law consists of three components: an equivalent control, a switching control and a tuning control. Given an excavation task in world space, inverse kinematic and dynamic models are used to convert the task into a desired digging trajectory in joint space. The proposed controller is applied to provide good tracking performance with attenuated vibration at bucket-soil contact points. From the control signals and the joint angles of the excavator, the piston position and ram force of each hydraulic cylinder for the axis control of the boom, arm, and bucket can be determined. The problem is then how to find the control voltage applied to each servovalve to achieve force and position tracking of each electrohydraulic system for the axis motion of the boom, arm, and bucket. With an observer-based compensation for disturbance force including hydraulic friction, tracking of the piston ram force and position is guaranteed using robust sliding control. High performance and strong robustness can be obtained as demonstrated by simulation and experiments performed on a hydraulically actuated robotic excavator. The results obtained suggest that the proposed control technique can provide robust performance when employed in autonomous excavation with soil contact considerations.