Stop Characteristics Research Articles

Does proximity to service providers impact punitivity in stop outcomes for individuals experiencing homelessness?

ABSTRACT The purpose of this study is to examine whether there is a relationship between the formality of police stop outcomes (e.g., no action v. citation) for stops involving individuals experiencing homelessness and the distance of the stop to service providers. We combine several datasets from the city of San Diego to assess our research question, including: police administrative data from the California Department of Justice, location datasets of food banks, homeless shelters, emergency medical and behavior facilities, and detox centers. Using logistic regressions, we model two outcomes – formality of a stop outcome and noncriminal transportation – with distance to within-city service providers and stop characteristics. We find that as proximity to detox facilities and food banks increases, the likelihood of formal outcomes also increases. Yet, when stops occur farther from emergency housing resources there is a reduction in the likelihood of formal outcomes. As the proximity from food banks increases there is also an increase in the likelihood of noncriminal/caretaking transport. Increasing police accessibility to service providers may reduce the use of formal justice-system outcomes in police encounters with individuals experiencing homelessness, which may also reduce the unintended consequences of entering the justice system for individuals experiencing homelessness.

Design of single layer bowtie wide band-stop frequency selective surface with angular stability for C-band applications

This paper presents the design and analysis of a single-layer wide band-stop frequency selective surface (FSS) tailored for C-band applications. The proposed FSS design employs a modified bow-tie unit cell structure that enhances band stop characteristics, resulting in improved performance compared to traditional FSS geometry. The design process involves numerical simulations and optimization techniques to achieve the desired frequency response. A modified bowtie element with FR4 substrate comprises the proposed FSS which exhibits a resonant frequency of 6.0 GHz with a wide bandwidth of 4.84–6.96 GHz (35.93 %) and act as a band stop filter. The FSS is analyzed in terms of its transmission coefficients, providing insight into its filtering properties. In addition, parametric studies of the unit cells are done. Furthermore, the angular stability of the proposed FSS is simulated with incident waves at various angles between 0° to 60° for both TE and TM modes. The proposed FSS presents C-band applications of WLAN, ISM/WiMAX, satellite communications, radar systems, shielding and communication devices, also enhancing filtering capabilities and system performance. The simulation results are well correlated with measurement results.

Identifying alternative stops for first and last-mile urban travel planning

Urban travelers today are seeking increasingly more information to plan their optimal trip, based on additional factors other than scheduled departure times. Still, some route planning applications provide a simple approach with a few parameter settings (e.g. to minimize travel time between two specific places at a certain time) and without any multimodal solutions. Our approach provides travelers with a set of non-dominated nearby stops that presents a number of traveler preferences in an easily comprehensible and quickly calculable manner. We display first and last-mile stops that fall on a Pareto front based on multiple criteria such as travel time, number of transfers, and frequency of service. Our algorithm combines stop and route-based information to quickly present the traveler with numerous nearby quality options for their itinerary decision making. We expand this algorithm to include multimodal itineraries with the incorporation of free-floating scooters to investigate the change in stop and itinerary characteristics. We then analyze the results on the star-shaped public transportation network of Göttingen, Germany, to show what advantages stops on the Pareto front have as well as demonstrate the increased effect on frequency and service lines when incorporating a broadened multimodal approach.

Experimental Investigation of Thermoacoustics and High-Frequency Combustion Dynamics with Band Stop Characteristics in a Pressurized Combustor

In combustor systems, thermoacoustic instabilities may occur and must be avoided for reliable operation. An acoustic network model can be used to predict the eigenfrequencies of the instabilities and the growth rate by incorporating the combustion dynamics with a flame transfer function (FTF). The FTF defines the interconnection between burner aerodynamics and the rate of combustion. In the current study, the method to measure the FTF in a pressurized combustor is explored. A siren unit, mounted in the fuel line, induced a fuel flow excitation of variable amplitude and high maximum frequency. This was performed here for pressurized conditions at 1.5 bar and 3 bar and at a thermal power of 125 kW and 250 kW. In addition to the experimental investigation, a 1-D acoustic network model approach is used. In the model, thermoviscous damping effects and reflection coefficients are incorporated. The model results compare well with experimental data, indicating that the proposed method to determine the FTF is reliable. In the approach, a combination of an FTF with a band stop approach and a network modeling approach was applied. The method provides a good match between experimentally observed behavior and an analytical approach and can be used for instability analysis.

Research Progress on the Dynamic Stability of Dry Gas Seals

Concerning the application of high-precision, enormous rotating equipment under harsh working conditions, the advantages of dry gas sealing technology are increasingly obvious. Herein, research on the dynamic stability of dry gas seals is reviewed based upon their operating mechanisms. The influence of the dry gas seal structure, vibration response, and dynamic followability on the reliability of the shaft end sealing system of rotating machinery is the focus of current dry gas sealing technology. This work reviews the research history; analyzes the key coefficient of the instability of the sealing system under external disturbances, and the existing research on stability models; discusses the influence of starting and stopping characteristics, working conditions, and groove parameters on the stability of dry gas seals; and points out the shortcomings in the existing research. In addition, potential developments in dynamic stability are proposed, including improving model accuracy, improving experimental techniques, or applying intelligent control and optimization methods to enhance the dynamic stability of the sealing system. Finally, the development prospects for dry gas sealing technology in intelligent monitoring and wide temperature range adaptations are discussed, and theoretical guidance for improving a dry gas seal system is provided.

Application of Public Transit AVL Data for Evaluation of Delay Variability

The travel time is the significant factor in evaluating efficiency and performance of public transit system. A greater percentage of travel time is accounted by bus stop delays which depends on passenger count, bus stop characteristics, traffic condition, bus performance, etc. Many of the Indian transit agencies store the passenger details stage wise not stop wise, which makes it difficult to evaluate delay variability at bus stop level. In this connection, Automatic Vehicle Location (AVL) data from Intelligent Transport System (ITS) implemented at Mysore, India is considered for evaluating bus stop delay variability. The collected data is used for estimating delay at five stops by adopting trajectory-based formulation. The probability distributions have been utilized to model the variability in delay. The performance has been analysed using Kolmogorov-Smirnov (KS) test. The daily variability of delay at bus stops has been evaluated using Coefficient of Variation (COV). The results of the performance evaluation of delay distributions show that the Generalized Extreme Value (GEV) distribution is the best descriptor of the delay variability in terms of accuracy, robustness, and survival capacity. In the absence of passenger data collection systems, method of evaluation of delay using AVL data presented in this study is helpful.

Aggregation Dispatch and Control Strategies for Multi-Type Loads in Industrial Parks

With the continuous expansion of renewable energy construction, the power system requires a larger-scale flexible dispatchable and controllable resource for power balance. Fully tapping into the power regulation capability of multi-type loads in industrial parks, making them a low-cost flexible dispatchable and controllable resource, is an effective approach to establish power regulation capability at scale in the new power system. However, the control characteristics of multi-type loads in industrial parks vary greatly, and their control delay characteristics, response speed, and sustainable response time are all different. Traditional dispatch and control methods cannot achieve precise control of the massive and multi-type loads in industrial parks. Therefore, this paper establishes unified models for the control characteristics of multi-type loads in industrial parks, quantitatively characterizes their control delay characteristics, start–stop characteristics, and control response speed. Based on this, the aggregated dispatch and control model and dispatch and control strategy for multi-type loads in industrial parks are developed, which provide a predictive control rate for individual loads considering the delay and segmented response characteristics to achieve precise aggregation control of multi-type loads in industrial parks. Simulation results show that the aggregated dispatch and control model and its aggregated dispatch and control strategy achieve precise control of multi-type loads in industrial parks. Flexible dispatchable and controllable loads can provide low-cost power regulation capability for the new power system.

Toolkit for the Assessment of Safety at Bus Stops

Safety at bus stops is a major concern of transit agencies. This research aimed to develop a data-driven method for estimating bus stop safety scores that will assist transit agencies in ranking and prioritizing bus stops for improvement considerations. This study presents a bus stop scoring methodology that uses a data-driven approach based on multiple data sources. The methodology was developed using six criteria: bus stop characteristics inventory, roadway characteristics inventory (RCI), land use and demographics, pedestrian crash frequency, annual average daily traffic, and annual ridership. Crash data were collected from SignalFour Analytics, and roadway characteristics data were retrieved from the Florida Department of Transportation RCI database. The Florida Geographic Data Library was used for retrieving census and land use data, while the Florida Transit Information System was employed to extract information on transit stops. A data-driven method was used to develop a priority list for improvements among the selected bus stops. The methodology was implemented in a case study including three transit agencies: Hillsborough Area Regional Transit Authority, Jacksonville Transportation Authority, and Miami-Dade Transit. A bus stop priority list was generated for each agency, with the highest-ranking bus stop location having the greatest need for safety improvements. Based on the analysis, safety measures that could improve safety at the highest-ranking bus stop locations include: installing a shelter, installing pedestrian safety features, conducting pedestrian safety outreach programs, and/or conducting further site investigation.

Representative truck activity patterns from anonymous mobile sensor data

• Anonymous Global Positioning System data can be mined for truck activity patterns. • Stop and trip characteristics of a truck represent its daily activity pattern. • Truck operational types can be represented by six unique daily activity patterns. With new sources of big data, it is increasingly possible to practically implement advanced freight forecasting models including activity-based and truck touring models. Such models improve upon traditional trip-based approaches by capturing freight behaviors sensitive to transportation policy and infrastructure changes. A persistent challenge with the use of big data in this context is the ability to generalize a set of representative behaviors to serve as the basis for model calibration and validation from anonymized data depicting the complex behaviors of the population. To address this challenge, we present a two-stage methodology to extract unique and representative freight activity patterns from passively collected truck Global Positioning System (GPS) data. The first stage involved a heuristic-based approach to derive a set of stop and trip characteristics from large-streams of GPS pings. The second stage employed data mining and machine learning techniques to discern common freight activity patterns from the set of defined features. The resulting activity pattern profiles, defined as chains of activities and their trajectories over time and space, allow us to maintain the anonymity of the trucks included in the GPS dataset while providing high-resolution travel profiles- a necessary condition for most data sharing agreements between public agencies and private data providers. These activity patterns serve as the critical, and currently missing, data needed to calibrate and validate advanced freight forecasting models. With more advanced forecasting models reflective of observed freight behaviors, we will be able to evaluate a wider spectrum of policy and infrastructure scenarios more accurately.

Field Stop (FS) Type IGBT Transient Temperature Characteristics: E-Thermal Simulation Approach

This research presents an electro-thermal simulation method for analyzing the transient temperature characteristics of Field Stop (FS) type Insulated Gate Bipolar Transistors (IGBTs). The method combines IGBT working principles and semiconductor physical principles to investigate the influence of internal excess carrier lifetime on the IGBT's transient temperature behavior. By conducting actual tests on an FS type IGBT switching transient working process, the research establishes an electro-thermal simulation method with improved accuracy and simplified parameter calculation.

Research on Crack Stop Characteristics of Integrally Stiffened Structure for Spacecraft Pressured Modules

Research on Crack Stop Characteristics of Integrally Stiffened Structure for Spacecraft Pressured Modules

Risk Area Identification Model of Bus Bay Stops Based on Distribution of Conflicts

Effective identification of the risk area of the bus bay stop is a prerequisite for the enhancement of traffic safety. This study proposes a method of identifying the risk area based on the distribution of traffic conflicts. Firstly, the traffic flow data of the bus stop is collected by drones and video recognition software, and the traffic flow characteristics of the bus stop are analyzed by the mathematical and statistical methods. Secondly, using the gray clustering evaluation theory, on the basis of the rasterization of the functional area of the bus bay stop, a risk level model based on the index system of conflict rate, conflict severity, and potential conflict risk is proposed. Finally, take a bus stop in Guangzhou as an example to verify the solution. The results show that the constructed model can effectively identify the risk areas of bus bay stops. The risk areas of the bus bay stops are concentrated in the middle and lower reaches of the bus stop, which proves that the impact of bus exiting the stop on the surrounding traffic is greater than the process of bus entering the stop; the traffic risk areas of lanes near the bus stop are concentrated, and the severity of conflicts is low. The traffic risk zone of the lane far away from the bus stop is widely distributed, and the severity of conflict is higher. The research results can provide a basis for the micro safety performance evaluation and safety optimization of bus bay stops, which has strong theoretical and practical significance.

Glottal stops do not constrain lexical access as do oral stops.

This study explores processing characteristics of a glottal stop in Maltese which occurs both as a phoneme and as an epenthetic stop for vowel-initial words. Experiment 1 shows that its hyperarticulation is not necessarily mapped onto an underlying form, although listeners may interpret it as underlying at a later processing stage. Experiment 2 shows that listeners’ experience with a particular speaker’s use of a glottal stop exclusively as a phoneme does not modulate competition patterns accordingly. Not only are vowel-initial words activated by [ʔ]-initial forms, but /ʔ/-initial words are also activated by vowel-initial forms, suggesting that lexical access is not constrained by an initial acoustic mismatch that involves a glottal stop. Experiment 3 reveals that the observed pattern is not generalizable to an oral stop /t/. We propose that glottal stops have a special status in lexical processing: it is prosodic in nature to be licensed by the prosodic structure.

Design and Synthesis of Multi-Mode Bandpass Filter for Wireless Applications

In this paper, a compact bandpass filter with improved band stop and band pass characteristics for wireless applications is built with four internal conductive poles in a single resonating cavity, which adds novel quad-resonating modes to the realization of band pass filter. This paper covers the design and testing of the S-band combline coaxial cavity filter which is beneficial in efficient filtering functions in wireless communication system design. The metallic cavity high Q coaxial resonators have the advantages of narrowband, low loss, better selectivity and high potential for power handling, as compared to microstrip filter in the application to determine the quality factor of motor oils. Furthermore, the tuning of coupling screws in the combline filter allows in frequency and bandwidth adjustments. An impedance bandwidth of 500 MHz (fractional bandwidth of 12.8%) has been achieved with an insertion loss of less than 2.5 dB and return loss of 18 dB at the resonant frequency. Four-pole resonating cavity filters have been developed with the center frequency of 4.5 GHz. Insert loss at 0 dB and estimated bandwidth at 850 MHz and a quality factor of 4.3 for the band pass frequencies between 4 and 8 GHz is seen in the simulated result.

A multi-chamber piezoelectric pump based on pumping unit with double circular piezoelectric unimorph actuators

For improving flow rate of multi-chamber piezoelectric pump with active valves, principle and structure of multi-chamber piezoelectric pump based on pumping unit with double circular piezoelectric unimorph actuators (CPUAs) are proposed. Double CPUAs are coaxially and symmetrically arranged on top and bottom of pump chamber and work in same frequency and phase at same time to provide driving force for pump. Two active piezoelectric valves with annular boundary are designed on left and right of pumping unit to ensure the multi-chamber piezoelectric pump bidirectionally pump fluid with high control accuracy and stop characteristics. Process compatible with printed circuit board (PCB) process is used to manufacture pump to ensure low cost. Flow rate model is established to numerically simulate flow characteristics of the pump. Pump is also experimentally tested and analyzed. Results show that proposed principle and structure can effectively improve flow rate and out pressure of multi-chamber piezoelectric pump with high control accuracy and stop characteristics of flow. Moreover, flow rate model can accurately describe its flow characteristics, which will be beneficial to design and optimize multi-chamber piezoelectric pumps with active valves. Proposed principle and structure of multi-chamber piezoelectric pumps with active valves have potential applications in complex microfluidic systems such as biochemical analysis, drug delivery and chip cooling.

Energy management and emission control for range extended electric vehicles

Range extended electric vehicles (REEVs), transition vehicles between combustion engine vehicles and electric vehicles, have been widely used due to their advantages of low fuel consumption and low emissions. By optimizing power management and after-treatment system control strategies, it is possible to achieve lower fuel consumption and emissions. This study proposes an integrated control method based on optimization strategies for the auxiliary power unit (APU) on/off system and energy management optimization for extended hybrid electric vehicles. The Elitist Nondominated Sorting Genetic Algorithm (NSGA-II) optimization method is used to determine the control parameters. In addition, considering the frequent start and stop characteristics of the APU caused by the optimization strategy, closed-loop control of the urea injection is established to solve the ammonia leakage problem. Due to their high computational efficiency, the proposed energy management and urea injection algorithms can be easily implemented in real time. The actual operating emissions of engines under the different strategies are tested on a semi-physical simulation platform, focusing on the analysis and comparison of NOx emissions. The conclusion has certain reference significance for vehicle production.

Low-profile, wideband dual-polarized 1 × 2 MIMO antenna with FSS decoupling technique

AbstractA low-profile, wideband dual-polarized 1 × 2 multiple-input-multiple-output (MIMO) antenna with frequency selective surface (FSS) decoupling technique is presented. Low profile is realized with two different artificial magnetic conductor (AMC) cells out of which one operates at 3.5 GHz and other with dual band at 3.1 and 4.5 GHz. The proposed antenna height is maintained at 0.125λ0 which is significantly reduced when compared with the conventional perfect electric conductor (PEC) ground plane. Wideband dual polarization is enabled by two pairs of bow-tie antenna elements surrounded by a square ring placed in the orthogonal orientation. To mitigate the near-field coupling in 1 × 2 MIMO an FSS wall is constructed with wide band stop characteristics from 2.85 to 4.75 GHz. Measured results show by inserting FSS wall vertically, coupling reduction is improved by 27 dB over the existing coupling and the antenna exhibits a bandwidth of 57.14% (2.95–4.95 GHz) for VSWR<2 with port isolation of more than 25 dB for entire band of operation.

Stop-and-frisk in New York City: Estimating racial disparities in post-stop outcomes

PurposeDetermine whether black and Latino pedestrians are more likely to be frisked or subjected to the use of force under New York City's stop-and-frisk program. MethodsInverse probability weighted regression adjustment and covariate exact matching were used on the New York City Police Department's stop-and-frisk data from 2008 to 2012 to estimate the average treatment effect on the treated (i.e. the effect of being black or Latino) on four post-stop outcomes (being frisked, being subjected to any force, being subjected to weapon force, and being subjected to non-weapon force). ResultsThe results show that being black or Latino is associated with being frisked and subjected to non-weapon force. Race and ethnicity are not associated with weapon force. ConclusionsResults are contextualized in terms of threat theory, administrative and organizational policy, and implicit bias. Because black and Latino pedestrians are still more likely to be frisked and subjected to non-weapon force after matching for relevant pedestrian and stop characteristics, particular attention is paid to the role of implicit bias.

Receding Horizon Cooperative Platoon Trajectory Planning on Corridors with Dynamic Traffic Signal

In this paper, a trajectory control approach using model predictive control is proposed for cooperative (automated) vehicles. This control approach optimizes accelerations of the controlled connected and automated vehicle (CAV) platoon along a corridor with signalized intersections. The objectives of the proposed approach are to maximize the throughput first and optimize comfort, travel delay, and fuel consumption simultaneously after that. The throughput is determined according to the maximal number of CAVs that can pass the intersection during the green phase. Safety is included by penalizing smaller gaps between CAVs in the running cost. The red phase is taken into account as a virtual vehicle at the stop-line during the red time, thus the safe gap penalty with the virtual vehicle causes the first-stopping vehicle to decelerate or even stop facing the red phase. The acceleration and speed are constrained within the upper and lower bounds. The proposed approach is flexible in dealing with platoon merging, splitting, stopping, and queue-discharging characteristics at signalized intersections. Finally, the proposed control approach is verified by simulation under a baseline scenario and four scenarios, which consider signal settings and the anticipation of the red phase. The simulation results demonstrate the benefits of the proposed control approach on fuel savings, compared with the state-of-art approach which used the virtual vehicle term without anticipation. The adjustments of signal parameters in Scenario 3 and Scenario 4 demonstrate the applicability of the control approach under actuated signal control.

Double-Layer Microstrip Band Stop Filters Etching Periodic Ring Electromagnetic Band Gap Structures

The electromagnetic band gap structure (EBGs) is widely used in microwave engineering, such as amplifiers, waveguides, microstrip filters, due to the fact of its excellent band stop characteristics. In this paper, three kinds of microstrip band stop filters were proposed which were etched with a hexagonal ring EBGs, octagonal ring EBGs and elliptical ring EBGs. Firstly, the etching coefficient of a band stop filter is proposed, and the performance of filters with different etching coefficient was analyzed. Secondly, the equivalent circuit of an EBGs band stop filter is proposed. By comparing the simulation results using advanced design system (ADS) and high frequency structure simulator (HFSS), it was found that the simulation results had the same −10 dB stopband width which verifies the correctness of the equivalent circuit model. Finally, three kinds of microstrip stopband filters were fabricated and measured. The experimental results of the −10 dB stopband width and resonant frequency were in good agreement with the simulation results. The −10 dB stopband fractional bandwidth of the three kinds of microstrip stopband filters was more than 63%. The proposed microstrip band stop filters can be widely used in microwave devices with a wide stopband.