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At present, the Newmark Sliding Block Method is adopted as a seismic evaluation method of embankments in Japan. The threshold acceleration during shaking is supposed to be a constant in the Newmark Sliding Block Method. However, threshold acceleration can be varied during strong earthquake motions. In this study, several dynamic centrifuge model tests were carried out to investigate the threshold acceleration of embankments during the shaking. The compensation in the Newmark Sliding Block Method was proposed considering variations in threshold acceleration. The test data indicate that the threshold acceleration of the embankments has a tendency to decrease during an earthquake.

Traffic safety is important in reducing death and building a harmonious society. In addition to studies of accident incidences, the perception of driving risk is significant in guiding the implementation of appropriate driving countermeasures. Risk assessment can be conducted in real-time for traffic safety due to the rapid development of communication technology and computing capabilities. This paper aims at the problems of difficult calibration and inconsistent thresholds in the existing risk assessment methods. It proposes a risk assessment model based on the potential field to quantify the driving risk of vehicles. Firstly, virtual energy is proposed as an attribute considering vehicle sizes and velocity. Secondly, the driving risk surrogate(DRS) is proposed based on potential field theory to describe the risk degree of vehicles. Risk factors are quantified by establishing submodels, including an interactive vehicle risk surrogate, a restrictions risk surrogate, and a speed risk surrogate. To unify the risk threshold, acceleration for implementation guidance is derived from the risk field strength. Finally, a naturalistic driving dataset in Nanjing, China, is selected, and 3063 pairs of following naturalistic trajectories are screened out. Based on that, the proposed model and other models use for comparisons are calibrated through the improved particle optimization algorithm. Simulations prove that the proposed model performs better than other algorithms in risk perception and response, car-following trajectory, and velocity estimation. In addition, the proposed model exhibits better car-following ability than existing car-following models.

By using low-cost microcontrollers and TinyML, we investigate the feasibility of detecting potential early warning signs of domestic violence and other anti-social behaviors within the home. We created a machine learning model to determine if a door was closed aggressively by analyzing audio data and feeding this into a convolutional neural network to classify the sample. Under test conditions, with no background noise, accuracy of 88.89\% was achieved, declining to 87.50\% when assorted background noises were mixed in at a relative volume of 0.5 times that of the sample. The model is then deployed on an Arduino Nano BLE 33 Sense attached to the door, and only begins sampling once an acceleration greater than a predefined threshold acceleration is detected. The predictions made by the model can then be sent via BLE to another device, such as a smartphone of Raspberry Pi., Comment: In Proceedings of the 2022 IEEE/ACM Seventh International Conference on Internet-of-Things Design and Implementation (IoTDI) 2022

Fast and precise propagation of satellite orbits is required for mission design, orbit determination in support of operations and payload data analysis. This demand must also comply with the different accuracy requirements set by a growing variety of scientific and service missions. This contribution proposes a method to improve the computational performance of orbit propagators through an efficient numerical integration that meets the accuracy requirements set by the specific application. This is achieved by appropriately tuning the parameters of the numerical propagator (relative tolerance and maximum time step), establishing a threshold for the perturbing accelerations (Earth's gravitational potential, atmospheric drag, solar radiation pressure, third-body perturbations, relativistic correction to gravity) below which they can be neglected without altering the quality of the results and implementing an efficient and precise algorithm for the harmonic synthesis of the geo-potential and its first-order gradient. In particular, when performing the harmonic synthesis, the number of spherical harmonics to retain (i.e., the expansion degree) is determined by the accuracy requirement. Given that higher-order harmonics decay rapidly with altitude, the expansion degree necessary to meet the target accuracy decreases with height. To improve the computational efficiency, the number of degrees to retain is determined dynamically while the trajectory is being computed. The optimum expansion degree for each altitude is determined by ensuring that the truncation error of the harmonic synthesis is below the threshold acceleration. The work is a generalization to arbitrary orbits of a previous study that focused on communication satellites in geosynchronous inclined orbits. The method is presented and a set of test cases is analysed and discussed., Comment: 70th International Astronautical Congress (IAC), Washington D.C., USA, 21-25 October 2019. Paper IAC-19-C1.3.8

Vibratory installation of sheet piles is the most economic and suitable for the sandy soil because of its mechanism. However, the process induces excess pore pressure in saturated conditions leading to subsidence. This research focuses on the development of a tool-based solution to predict the excess pore pressure due to vibratory installation, which shall be verified by the postdiction of Kademuur Damrak measurements. This tool will help engineers quantify the impact of generated excess pore pressure on adjacent structures. The proposed work attempted to achieve its objective by answering the following main and sub research questions. How can the existing knowledge on generation and evolution of porewater pressure during vibratory installation be effectively integrated into a model/tool, which verified by the postdiction of Kademuur Damrak measurements, can practically estimate the porewater over-pressure during vibratory installations? • What are the parameters that influence the dissipation of the excess pore pressure? • How does the generation and dissipation of excess pore pressure vary in the liquefied zone from non-liquefied? • How can the vibration attenuation affect the generation of excess pore pressure in the sand? • What are the limitations and controlling parameters of this model or tool? The proposed work combines dynamic soil response and transient groundwater flow model to simulate the evolution of pore pressure due to vibratory loading. Based on the degree of modulus degradation due to the vibratory loading the soil, it is zoned into three. This is also termed as a multiscale computational framework. This allows for the formations liquefied and non-liquefied zone. The threshold acceleration of 0.1g - 0.3g must be available for the soil to liquefy [66]. The non- liquefied zone is fed by the groundwater flow from the liquefied zone. According to the Theis equation, head response due to constant pumping in an aquifer is influenced by the rate of discharge (V), sto

Fast and precise propagation of satellite orbits is required for mission design, orbit determination in support of operations and payload data analysis. This demand must also comply with the different accuracy requirements set by a growing variety of scientific and service missions. This contribution proposes a method to improve the computational performance of orbit propagators through an efficient numerical integration that meets the accuracy requirements set by the specific application. This is achieved by appropriately tuning the parameters of the numerical propagator (relative tolerance and maximum time step), establishing a threshold for the perturbing accelerations (Earth's gravitational potential, atmospheric drag, solar radiation pressure, third-body perturbations, relativistic correction to gravity) below which they can be neglected without altering the quality of the results and implementing an efficient and precise algorithm for the harmonic synthesis of the geo-potential and its first-order gradient. In particular, when performing the harmonic synthesis, the number of spherical harmonics to retain (i.e., the expansion degree) is determined by the accuracy requirement. Given that higher-order harmonics decay rapidly with altitude, the expansion degree necessary to meet the target accuracy decreases with height. To improve the computational efficiency, the number of degrees to retain is determined dynamically while the trajectory is being computed. The optimum expansion degree for each altitude is determined by ensuring that the truncation error of the harmonic synthesis is below the threshold acceleration. The work is a generalization to arbitrary orbits of a previous study that focused on communication satellites in geosynchronous inclined orbits. The method is presented and a set of test cases is analysed and discussed., Comment: 70th International Astronautical Congress (IAC), Washington D.C., USA, 21-25 October 2019. Paper IAC-19-C1.3.8

Vibratory installation of sheet piles is the most economic and suitable for the sandy soil because of its mechanism. However, the process induces excess pore pressure in saturated conditions leading to subsidence. This research focuses on the development of a tool-based solution to predict the excess pore pressure due to vibratory installation, which shall be verified by the postdiction of Kademuur Damrak measurements. This tool will help engineers quantify the impact of generated excess pore pressure on adjacent structures. The proposed work attempted to achieve its objective by answering the following main and sub research questions. How can the existing knowledge on generation and evolution of porewater pressure during vibratory installation be effectively integrated into a model/tool, which verified by the postdiction of Kademuur Damrak measurements, can practically estimate the porewater over-pressure during vibratory installations? • What are the parameters that influence the dissipation of the excess pore pressure? • How does the generation and dissipation of excess pore pressure vary in the liquefied zone from non-liquefied? • How can the vibration attenuation affect the generation of excess pore pressure in the sand? • What are the limitations and controlling parameters of this model or tool? The proposed work combines dynamic soil response and transient groundwater flow model to simulate the evolution of pore pressure due to vibratory loading. Based on the degree of modulus degradation due to the vibratory loading the soil, it is zoned into three. This is also termed as a multiscale computational framework. This allows for the formations liquefied and non-liquefied zone. The threshold acceleration of 0.1g - 0.3g must be available for the soil to liquefy [66]. The non- liquefied zone is fed by the groundwater flow from the liquefied zone. According to the Theis equation, head response due to constant pumping in an aquifer is influenced by the rate of discharge (V), sto

© Published under licence by IOP Publishing Ltd. We proposed an autoparametric excitation harvester employing a microfabricated leaf spring for the base beam and a synchronized switch harvesting on inductor (SSHI) interface. Our harvester achieved miniaturization, low threshold acceleration of the autoparametric excitation, and increase in output power, compared with the previous work. The base beam for amplifying the excitation was microfabricated from a stainless steel film, through the photolithography followed by the wet-chemical etching. To trigger the autoparametric excitation, the main and the base beams are designed such that the resonance frequency for the base beam becomes twice higher than that for the main beam. The resonance frequencies obtained in experiment for the main and the base beams were 26.6 and 53.1 Hz, respectively. This study employed a self-powered parallel SSHI interface, which can increase the piezoelectric voltage and thus the output power, consuming only a small portion of the harvested energy. The harvester connected with the self-powered SSHI interface successfully displayed the autoparametric excitation at acceleration greater than 1.0 m/s2, and the output power showed 1.12 mW at the frequency of 53.1 Hz under the acceleration of 2.0 m/s2, which is 1.43-fold increase over the standard AC-DC interface.

Microelectromechanical systems (MEMS) three-axis acceleration threshold sensors have been developed to measure acceleration threshold levels using voltage switching when the threshold is reached. Determining damping coefficients is important for categorizing how each threshold sensor or switch operates. Switches with different damping coefficients result in different mechanical impedances and response times. Analytical and numerical methods to model damping coefficient values based on empirical data are needed to characterize three-axis acceleration sensors; traditional methods use the displacement of an underdamped system to calculate the damping ratio. Mechanical switches are single output devices that distinguish whether closure occurs or not and lack a transduction mechanism to turn acceleration into a readable displacement signal. Thus, we have devised a more inventive technique to analyze a closed switch. A shock table and vibration testing produces a deterministic acceleration input to close an acceleration switch, which has a defined switch gap distance, and mathematical fitting using these deterministic values allows one to determine damping coefficients. By using both an analytical equation fit method and a numerical optimization program, the damping coefficients for MEMS three-axis threshold acceleration sensors were calculated from the results of the tests and design dimensions of the switches., The original document contains color images.

This paper deals with nearly inviscid, capillary?gravity, modulated waves parametrically excited by monochromatic horizontal vibrations in liquid containers whose width and depth are both large compared with the wavelength of the excited waves. A general linear amplitude equation is derived with appropriate boundary conditions that provides the threshold acceleration and associated spatiotemporal patterns, which compare very well with experimental measurements and visualizations. The primary instability is associated with a pair of complex Floquet multipliers that are close to (but strictly different from) ?1, meaning that the instability is not strictly (2:1) subharmonic. The resulting (quasi-periodic) waves are generally oblique, not perpendicular to the vibrating endwalls. The extension of the theory to other confined systems such as vibrating containers of arbitrary shape and vibrating drops is also considered.

This paper deals with nearly inviscid, capillary?gravity, modulated waves parametrically excited by monochromatic horizontal vibrations in liquid containers whose width and depth are both large compared with the wavelength of the excited waves. A general linear amplitude equation is derived with appropriate boundary conditions that provides the threshold acceleration and associated spatiotemporal patterns, which compare very well with experimental measurements and visualizations. The primary instability is associated with a pair of complex Floquet multipliers that are close to (but strictly different from) ?1, meaning that the instability is not strictly (2:1) subharmonic. The resulting (quasi-periodic) waves are generally oblique, not perpendicular to the vibrating endwalls. The extension of the theory to other confined systems such as vibrating containers of arbitrary shape and vibrating drops is also considered.

Globular clusters are useful to test the validity of Newtonian dynamics in the low acceleration regime typical of galaxies, without the complications of non-baryonic dark matter. Specifically, in absence of disturbing effects, e.g. tidal heating, their velocity dispersion is expected to vanish at large radii. If such behaviour is not observed, and in particular if, as observed in elliptical galaxies, the dispersion is found constant at large radii below a certain threshold acceleration, this might indicate a break down of Newtonian dynamics. To minimise the effects of tidal heating in this paper we study the velocity dispersion profile of two distant globular clusters, NGC 1851 and NGC 1904. The velocity dispersion profile is derived from accurate radial velocities measurements, obtained at the ESO 8m VLT telescope. Reliable data for 184 and 146 bona fide cluster star members, respectively for NGC 1851 and NGC 1904, were obtained. These data allow to trace the velocity dispersion profile up to ~2r0, where r0 is the radius at which the cluster internal acceleration of gravity is a0 = 10e-8 cm/s/s. It is found that in both clusters the velocity dispersion becomes constant beyond ~r0. These new results are fully in agreement with those found for other five globular clusters previously investigated as part of this project. Taken all together, these 7 clusters support the claim that the velocity dispersion is constant beyond r0, irrespectively of the specific physical properties of the clusters: mass, size, dynamical history, and distance from the Milky Way. The strong similarly with the constant velocity dispersion observed in elliptical galaxies beyond r0 is suggestive of a common origin for this phenomenon in the two class of objects, and might indicate a breakdown of Newtonian dynamics below a0., Comment: Accepted for publication by A&A main journal. 12 pages, 12 figures

Globular clusters are useful to test the validity of Newtonian dynamics in the low acceleration regime typical of galaxies, without the complications of non-baryonic dark matter. Specifically, in absence of disturbing effects, e.g. tidal heating, their velocity dispersion is expected to vanish at large radii. If such behaviour is not observed, and in particular if, as observed in elliptical galaxies, the dispersion is found constant at large radii below a certain threshold acceleration, this might indicate a break down of Newtonian dynamics. To minimise the effects of tidal heating in this paper we study the velocity dispersion profile of two distant globular clusters, NGC 1851 and NGC 1904. The velocity dispersion profile is derived from accurate radial velocities measurements, obtained at the ESO 8m VLT telescope. Reliable data for 184 and 146 bona fide cluster star members, respectively for NGC 1851 and NGC 1904, were obtained. These data allow to trace the velocity dispersion profile up to ~2r0, where r0 is the radius at which the cluster internal acceleration of gravity is a0 = 10e-8 cm/s/s. It is found that in both clusters the velocity dispersion becomes constant beyond ~r0. These new results are fully in agreement with those found for other five globular clusters previously investigated as part of this project. Taken all together, these 7 clusters support the claim that the velocity dispersion is constant beyond r0, irrespectively of the specific physical properties of the clusters: mass, size, dynamical history, and distance from the Milky Way. The strong similarly with the constant velocity dispersion observed in elliptical galaxies beyond r0 is suggestive of a common origin for this phenomenon in the two class of objects, and might indicate a breakdown of Newtonian dynamics below a0., Comment: Accepted for publication by A&A main journal. 12 pages, 12 figures

We consider the Floquet linear problem giving the threshold acceleration for the appearance of Faraday waves in large-aspect-ratio containers, without further restrictions on the values of the parameters. We classify all distinguished limits for varying values of the various parameters and simplify the exact problem in each limit. The resulting simplified problems either admit closed-form solutions or are solved numerically by the well-known method introduced by Kumar & Tuckerman (1994). Some comparisons are made with (a) the numerical solution of the original exact problem, (b) some ad hoc approximations in the literature, and (c) some experimental results.

We consider the Floquet linear problem giving the threshold acceleration for the appearance of Faraday waves in large-aspect-ratio containers, without further restrictions on the values of the parameters. We classify all distinguished limits for varying values of the various parameters and simplify the exact problem in each limit. The resulting simplified problems either admit closed-form solutions or are solved numerically by the well-known method introduced by Kumar & Tuckerman (1994). Some comparisons are made with (a) the numerical solution of the original exact problem, (b) some ad hoc approximations in the literature, and (c) some experimental results.

Micromechanical cantilever beam structures having a maximum length of 0.16 in. were designed, fabricated, and tested in six configurations for use as threshold acceleration sensors for projectile fuzes. Their small size and ability to be produced using monolithic fabrication techniques commonly used to make integrated circuits provides the possibility of incorporating multiswitch arrays into a single die surface area one hundredth of a square inch. Design, fabrication, and test details are provided for two triple-beam arrays of cantilever structures made from 3-micrometer-thick silicon dioxide. (Author)

This paper describes the application of a modified Newmarkian analysis method to the estimation of slope deformations during liquefaction-induced lateral spreading. The analysis method requires a pore-pressure history either predicted using a suitable constitutive model, or measured during a centrifuge or shaking-table test, to calculate the variation of threshold acceleration with time. Comparison of predicted displacements using this procedure and displacements measured in centrifuge mode1 tests with the same pore-pressure history shows good agreement.

Human-induced vibration has become a serious serviceability problem due to the larger opening of girder, lighter floor systems and longer spans designed and used in practice. Vibration tests were undertaken in laboratory to research the vibrational characteristics of the arch pre-stressed concrete truss (APT) system spanning 16.0 m. Results from ambient vibration, impulse excitations (heel-drop and jumping) and steady-state incentives (walking and running) were presented. Dynamic characteristics such as natural frequencies, damping ratios, mode shapes and acceleration responses were studied and checked against the existing codes. Experimental results show that the investigated APT girder possesses high fundamental frequency and low damping ratio. Moreover, the perception factors based on the root-mean-square acceleration, vibration dose value (VDV) and psychological comfort data were obtained. Lastly, the threshold accelerations and VDVs were suggested for evaluating the human-induced vibration.

運用光刻膠為注模的多次互不干擾金屬電鍍技術實現了慣性微型電學開關的低溫制造與封裝.電鍍技術的低溫過程可使微型開關直接成形于預先制作好的含有電子信號處理電路的基底上,加上同樣借助于低溫金屬電鍍技術的基于整個硅晶片的倒裝封裝,直接形成環繞各個器件的密封腔體.這一技術最終將使得模塊化生產成為現實.微型開關的高度和它的密封腔的高度可以分別控制.電子信號可以通過金屬互連線進入密封腔體.為了便于設計,建立了一個既簡單又相對準確的“彈簧質量塊”模型.以此設計的慣性開關,即使在未封裝的常溫、常壓條件下,均可工作109次以上.本文對密封腔體的強度和密封性,以及金屬互連線的可靠性,都作了詳細的檢測,各項指標均達到其各自的標準. Presented in this paper is a separate and non-interfering photoresist-molded, metal-electroplating technology for the low-temperature fabrication and packaging of inertia electrical micro-switch. The low temperature process of the electroplating technology allows eventual modular integration and wafer-level packaging of the micro-switches on active substrates containing pre-fabricated electronic signal-processing circuits. The height of the inertia micro-switch and that of its cavity are independently controlled. Metal leads are provided for electrical access to the sealed cavities. The switches are designed using a simple but accurate lumped spring-mass model. Un-encapsulated switches making over 100 million contacts are demonstrated in room ambient. Both the strength and the hermeticity of the sealed cavity are tested and reported.

Separate and non-interfering photo-resist molded metal-electroplating processes have been applied to the fabrication of inertia micro-switches and their wafer-level packaging in sealed cavities. The height of a switch and that of its cavity are independently controlled. The low process temperature allows eventual modular integration of switches on active substrates containing pre-fabricated electronic signal-processing circuits. The scheme also provides leads for electrical access to the sealed devices. The switches were designed using a simple but accurate lumped spring-mass model. With the application of an anti-stiction hydrophobic coating, un-encapsulated switches making over 100 million contacts have been demonstrated in room ambient. (C) 2003 Elsevier B.V. All rights reserved.

Separate and non-interfering photo-resist molded metal-electroplating processes have been applied to the fabrication of inertia micro-switches and their wafer-level packaging in sealed cavities. The height of a switch and that of its cavity are independently controlled. The low process temperature allows eventual modular integration of switches on active substrates containing pre-fabricated electronic signal-processing circuits. The scheme also provides leads for electrical access to the sealed devices. The switches were designed using a simple but accurate lumped spring-mass model. With the application of an anti-stiction hydrophobic coating, un-encapsulated switches making over 100 million contacts have been demonstrated in room ambient. (C) 2003 Elsevier B.V. All rights reserved.

Separate and non-interfering photo-resist molded metal-electroplating processes have been applied to the fabrication of inertia micro-switches and their wafer-level packaging in sealed cavities. The height of a switch and that of its cavity are independently controlled. The low process temperature allows eventual modular integration of switches on active substrates containing pre-fabricated electronic signal-processing circuits. The scheme also provides leads for electrical access to the sealed devices. The switches were designed using a simple but accurate lumped spring-mass model. With the application of an anti-stiction hydrophobic coating, un-encapsulated switches making over 100 million contacts have been demonstrated in room ambient. (C) 2003 Elsevier B.V. All rights reserved.

Inertia micro-switches have been designed and realized using a low-temperature metal-electroplating technology compatible with processed substrates containing micro-electronic circuits. A simple but accurate lumped spring-mass model is developed based on analytical and numerical analyses. Predictions of the behavior of switches with different geometric designs have been verified using both drop hammer and shaker tests. With the application of an anti-stiction hydrophobic coating, improved storage time and un-encapsulated switches making over 50 million contacts have been demonstrated in room ambient.

Inertia micro-switches have been designed and realized using a low-temperature metal-electroplating technology compatible with processed substrates containing micro-electronic circuits. A simple but accurate lumped spring-mass model is developed based on analytical and numerical analyses. Predictions of the behavior of switches with different geometric designs have been verified using both drop hammer and shaker tests. With the application of an anti-stiction hydrophobic coating, improved storage time and un-encapsulated switches making over 50 million contacts have been demonstrated in room ambient.

Inertia micro-switches have been designed and realized using a low-temperature metal-electroplating technology compatible with processed substrates containing micro-electronic circuits. A simple but accurate lumped spring-mass model is developed based on analytical and numerical analyses. Predictions of the behavior of switches with different geometric designs have been verified using both drop hammer and shaker tests. With the application of an anti-stiction hydrophobic coating, improved storage time and un-encapsulated switches making over 50 million contacts have been demonstrated in room ambient.