Enabling Fine Sample Rate Settings in DSOs with Time-Interleaved ADCs

The time-base used by digital storage oscilloscopes allows limited selections of the sample rate, namely constrained to a few integer submultiples of the maximum sample rate. This limitation offers the advantage of simplifying the data transfer from the analog-to-digital converter to the acquisition memory, and of assuring stability performances, expressed in terms of absolute jitter, that are independent of the chosen sample rate. On the counterpart, it prevents an optimal usage of the memory resources of the oscilloscope and compels to post processing operations in several applications. A time-base that allows selecting the sample rate with very fine frequency resolution, in particular as a rational submultiple of the maximum rate, is proposed. The proposal addresses the oscilloscopes with time-interleaved converters, that require a dedicated and multifaceted approach with respect to architectures where a single monolithic converter is in charge of signal digitization. The proposed time-base allows selecting with fine frequency resolution sample rate values up to 200 GHz and beyond, still assuring jitter performances independent of the sample rate selection.

Развитие технологии настройки акустических систем при ультразвуковом контроле сварных соединений

The urgent task is improvement of the accuracy of diagnosing the linear part of pipelines, structures and equipment of pumping and compressor stations, tank batteries, tank farm complexes. Therewith, it is required not only to identify a defect with a given probability, but also to ensure measurement of its shape and dimensions with accuracy to be sufficient to perform analysis of structures for strength and durability. The article deals with certain possibilities for increasing the detectability of volumetric defects, such as knots, through improvement of the methods for setting parameters of ultrasound pulse-echo testing. The results of research in the field of improvement of the technology for setting advanced ultrasonic systems using phased array antennas are presented. Cylinder-shaped drilled holes of different orientations have been reviewed as artificial defects for setting sensitivity and time base of the flaw-detecting instrument. Following on the earlier published works, the expediency of using vertical cylindrical drilling for setting the equipment is additionally justified: such target is the easiest to manufacture, its parameters are verified much easier than, for example, the parameters of flatbottomed holes. Examples are given of the practical use of drills of various orientations for adjusting sensitivity of monitoring and determination of the indication length of local bulk defects of the base metal and welds. Актуальной является задача повышения точности диагностирования линейной части трубопроводов, сооружений и оборудования перекачивающих и компрессорных станций, резервуарных парков, нефтебаз. При этом требуется не просто выявить дефект с заданной вероятностью, но и обеспечить измерение его формы и размеров с точностью, достаточной для выполнения расчетов конструкций на прочность и долговечность. В статье рассмотрены некоторые возможности повышения выявляемости объемных дефектов типа свищей за счет совершенствования способов настройки параметров ультразвукового контроля эхо-методом. Представлены результаты исследований в области совершенствования технологии настройки современных ультразвуковых систем, использующих фазированные антенные решетки. В качестве искусственных дефектов для настройки чувствительности и временной развертки дефектоскопа рассмотрены цилиндрические сверления разной ориентации. В развитие ранее опубликованных работ обоснована целесообразность применения для настройки оборудования вертикального цилиндрического сверления: такая мишень наиболее проста в изготовлении, ее параметры поверяются значительно проще, чем, например, параметры плоскодонных отверстий. Приведены примеры практического использования сверлений различной ориентации для настройки чувствительности контроля и определения условной протяженности локальных объемных дефектов основного металла и сварных швов.

Employing of Object Tracking System in Public Surveillance Cameras to Enforce Quarantine and Social Distancing Using Parallel Machine Learning Techniques

Like many countries, Jordan has resorted to lockdown in an attempt to contain the outbreak of Coronavirus (Covid-19). A set of precautions such as quarantines, isolations, and social distancing were taken in order to tackle its rapid spread of Covid-19. However, the authorities were facing a serious issue with enforcing quarantine instructions and social distancing among its people. In this paper, a social distancing mentoring system has been designed to alert the authorities if any of the citizens violated the quarantine instructions and to detect the crowds and measure their social distancing using an object tracking technique that works in real-time base. This system utilises the widespread surveillance cameras that already exist in public places and outside many residential buildings. To ensure the effectiveness of this approach, the system uses cameras deployed on the campus of Al-Zaytoonah University of Jordan. The results showed the efficiency of this system in tracking people and determining the distances between them in accordance with public safety instructions. This work is the first approach to handle the classification challenges for moving objects using a shared-memory model of multicore techniques. Keywords: Covid-19, Parallel computing, Risk management, Social distancing, Tracking system.

Wireless Sensor Network-Based Mathematical Modeling for Communication Intelligent Monitoring System

Knowing the behavioral patterns of city residents is of great value in formulating and adjusting urban planning strategies, such as urban road planning, urban commercial development, and urban pedestrian flow control. Based on the high penetration rate of cell phones, it is possible to indirectly understand the behavior of city residents based on the call records of users. However, the behavioral patterns of large-scale users over a long period of time can present characteristics such as large dispersion, difficult to discover patterns, and difficult to explain behavioral patterns. In this paper, we design and implement a human behavior pattern analysis system based on massive mobile communication data based on serial data modeling method and visual analysis technology. For the problem that it is difficult to capture the behavioral patterns of residents in cities in call records, this paper constructs base station trajectories based on users’ cell phone call records and uses users’ long-time base station trajectories to mine users’ potential behavioral patterns. Since users with similar activity characteristics will exhibit similar base station trajectories, this paper focuses on the similarity between text sequences and base station trajectory sequences and combines the word embedding method in natural language processing to build a Cell2vec model to identify the semantics of base stations in cities. In order to obtain the group behavior patterns of users from the base station trajectories of group users, a user clustering method based on users’ regional mobile preferences is proposed, and the results are projected using the Stochastic Neighbor Embedding (t-SNE) algorithm to expose the clustering features of large-scale cell phone users in the low-dimensional space. To address the problem that user behavior patterns are difficult to interpret, a visual analysis model with group as well as regional semantics is designed for the spatial and temporal characteristics of user behavior. Among them, the clustering model uses the distance between scatter points to map the similarity between users, which helps analysts to explore the behavioral characteristics of group users.

Parametric Characterization and Analysis of Pounding Behavior Adjacent Multi-Storied Buildings of Varying Heights

Many past earthquake studies show that during strong vibrations, the adjacent building structures which are closely spaced to each other are vulnerable to severe damage when the adjacent buildings are not at an adequate distance to accommodate their relative displacements. The primary goal of this research is to find out the minimum separation gap between buildings of varying height at the same floor-to-floor height level. SAP 2000 software is used to analyze the structural behavior of building during the earthquake.Three building models are taken for the study, one is six floors (G+6) and another two are nine floors (G+9), and twelve floors (G+12) respectively. Six floors (G+6)& twelve floors (G+12) structures have the same floor to floor height and plan and same beam and column size (equal stiffness) and G+9 buildings have floor to floor height are same but different beam and column sizes (different stiffness). The linear dynamic (RSA) analysis method is used to calculate the response (Displacement, frequency at fundamental time, Base Shear) of the structure at different floors levels. Response (top story displacements) calculated from the response spectrum is compared with the provisions of seismic gap per story height given in IS 4326: 2005.

Method for Determining the Estimated Timing Uncertainty for Digital Sampling Instruments

The overall uncertainty in digital captured data points is often misunderstood in our organization and is typically accepted as only the manufacturer uncertainty specification of the time base clock typically on the order of 10-100 parts per million. The time base clock of digital sampling technologies is critically important to maintain timing control of the internal electronics and to achieve the specified sampling rate of the instrument. The time base clock must remain within the manufacturer specification tolerance throughout the calibration interval to assure accurate performance. However, the time base uncertainty does not adequately account for the additional measurement errors accompanying the capture and evaluation of the time values for any cardinal points of interest when periodically sampling analog waveforms generated by other instruments or Units Under Test (UUTs). The proposed methodology described here details a general approach used to estimate the magnitude of the digital instrument sampling error when capturing analog waveforms based upon the instrument sampling rate, the frequency of a nominally equivalent sinusoidal waveform, as well as, whether the time value of any cardinal points is selected by a ‘Next Point After’ or Interpolation method for our purposes. Finally, the overall estimated timing uncertainty is quantified by arithmetically combining the error contributions for the sampling rate, the cardinal point selection method, and the instrument time base specification. The results of this method aid in selecting the appropriate digital sampling technology based upon waveform rise time requirements and provide general engineering guidance. Since the estimated error is a portion of the sampling timestep interval, the percentage error could be significant based upon the measured rise time. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy National Nuclear Security Administration under contract DE-NA0003525.

Application of Comprehensive Geophysical Prospecting Method in Water Accumulation Exploration of Multilayer Goaf in Integrated Mine

A coal mine in Datong is an integrated mine. At present, there is goaf in the upper and lower part of the mining coal seam. There is a lot of ponding in the goaf, which has great potential safety hazards for production. In order to find out the scope and location of ponding in goaf, the comprehensive geophysical exploration method combining transient electromagnetic method and high-density resistivity method is used to carry out the research. Firstly, the time-base, turn-off time, receiving delay, current, superposition times, and other parameters of the instrument are tested on the surface of known goaf to obtain the best instrument parameters, and the parameters are used to verify the feasibility of the research scheme; then, the transient electromagnetic method is used for large-area exploration on the surface of the mine, the suspected goaf ponding area is found through comprehensive analysis, and the high-density resistivity exploration is arranged in the suspected goaf ponding area. According to the obtained results, the scope and location of the goaf ponding area are accurately located through comprehensive analysis. The results show that there are two goaf ponding areas in the exploration area, which are located above the 8# coal seam currently mined; the range and location of goaf ponding area can be accurately obtained by using the comprehensive geophysical method of high-density electrical method and transient electromagnetic method. This method can provide reference for mine water prevention and control in Datong area and has great practical significance to ensure coal mine safety production.

Analisis Kinerja Bangunan Gedung Tinggi Dengan Penambahan Dinding Geser (Studi Kasus: Bangunan 8 Lantai)

Shear walls in high-rise buildings serve to increase the resistance of high-rise buildings to lateral loads. This study aims to compare the structural performance of an existing 8 (eight) storey building designed as a special moment resisting frame structure against a building designed as a dual system, which consists of: structural vibration time, base shear force, displacement, and drift. Three configurations for shear walls are designed, as follows: (1) L-shaped located at the corner of one side of the building, totaling 2 (two) units (SW1); (2) L-shaped located at the four corners of the building totaling 4 (four) units (SW2); and 3) I-shaped located along the side of the building totaling 6 (six) units (SW3). Simulations are run using the Etabs by taking into account dead loads, live loads, and earthquake loads. The results show that the addition of shear walls can: (1) reduce the vibration period of the structure up to 62,55% in SW3, (2) increase the base shear force up to 86,34% in SW3, (3) reduce peak displacement up to 84,86% in SW3, and (4) reduce the drift between floors up to 89,58% in SW3. However, the SW2 is considered to be better applied to the building by taking into account the structural performance, effectiveness and efficiency factors.

Longitudinal Changes in Running Gait Asymmetries and Their Relationship to Personal Record Race Times in Collegiate Cross Country Runners

Minimizing between-limb asymmetries during running is often a goal of training, as increased asymmetries are related to decreased efficiency and increased energy expenditure. However, it is unknown if asymmetries change with increased running exposure or are related to actual race performance. The purpose of this study was to determine (1) if pre-season asymmetries changed year-to-year among collegiate cross country runners, and (2) if these asymmetries were associated with within-season personal records (PRs). Pre-season biomechanical test results and race performance data were analyzed for 54 unique runners (28 female) across six seasons, totaling 152 assessments (age: 19.1 (0.9) years, height: 1.71 (0.10) m, weight: 61.7 (7.7) kg (values = mean [standard deviation])). Biomechanical asymmetries included ground reaction forces; ground contact time; base of gait; foot inclination angle; and peak hip flexion, hip extension, hip adduction, pelvic drop, knee flexion, and ankle dorsiflexion. Year of collegiate eligibility was used to quantify training exposure. Asymmetries during running did not change across years of eligibility (p ≥ 0.12), except propulsive impulse, which decreased over time (p = 0.03). PR times were faster with decreased propulsive impulse asymmetry and increased AVLR and peak ankle dorsiflexion asymmetries. This is the first study to assess longitudinal asymmetries over time and provide potential targets for interventions aimed at modifying asymmetries to improve performance.