Stop Frequency Research Articles

Collaborative optimization of multi-modal transport solutions for urban-rural bus routes.

Faced with the land use heterogeneity and trip distribution non-equilibrium along the corridor connecting urban district and rural area, the operation characteristics of the all-stop bus, the express bus and the shuttle bus running on the transportation corridor should be given full consideration, as well as the tradeoff between passenger trip cost and bus operation cost during the peak-hour period. In order to realize the reliable decision of bus resources configuration for urban-rural public transportation, a bi-objective programming model of multi-modal urban-rural bus operation scheme is established, where the decision variables include the departure frequency of different bus modals, the terminals of shuttle buses, and the stop scheme of express buses, under the constraints of departure interval, passenger volume, vehicle occupancy, section capacity usage and modal competition. To validate the feasibility of proposed optimization model, an urban-rural bus corridor from Rural Jasmine Ecological Park in Hanjiang District to West Xiangyang Bridge in Songqiao Town was chosen as a study case, and the operation organization scheme of three bus modals were solved by the mathematical solver Lingo using mixed integer programming. Meanwhile, the scheme differences under different subobjective weights were discussed, taking into account the uncertain passenger demand and operation supply. The result shows that the increase of passenger trip cost weight will increase the departure frequency of all three bus modals, while the increase of operation cost weight will decrease the total operating vehicles, but the stop frequency at middle stations for express buses will increase accordingly. Compared to the current operation scheme, the optimized scheme can greatly enhance the section capacity usage at a slight sacrifice of passenger trip time with fewer bus vehicles.

Bayesian Interim Analysis and Efficiency of Phase III Randomized Trials.

Improving the efficiency of interim assessments in phase III trials should reduce trial costs, hasten the approval of efficacious therapies, and mitigate patient exposure to disadvantageous randomizations. We hypothesized that in silico Bayesian early stopping rules improve the efficiency of phase III trials compared with the original frequentist analysis without compromising overall interpretation. Cross-sectional analysis. 230 randomized phase III oncology trials enrolling 184,752 participants. Individual patient-level data were manually reconstructed from primary endpoint Kaplan-Meier curves. Trial accruals were simulated 100 times per trial and leveraged published patient outcomes such that only the accrual dynamics, and not the patient outcomes, were randomly varied. Early stopping was triggered per simulation if interim analysis demonstrated ≥ 85% probability of minimum clinically important difference/3 for efficacy or futility. Trial-level early closure was defined by stopping frequencies ≥ 0.75. A total of 12,451 simulations (54%) met early stopping criteria. Trial-level early stopping frequency was highly predictive of the published outcome (OR, 7.24; posterior probability of association, >99.99%; AUC, 0.91; P < 0.0001). Trial-level early closure was recommended for 82 trials (36%), including 62 trials (76%) which had performed frequentist interim analysis. Bayesian early stopping rules were 96% sensitive (95% CI, 91% to 98%) for detecting trials with a primary endpoint difference, and there was a high level of agreement in overall trial interpretation (Bayesian Cohen's κ, 0.95; 95% CrI, 0.92 to 0.99). However, Bayesian interim analysis was associated with >99.99% posterior probability of reducing patient enrollment requirements ( P < 0.0001), with an estimated cumulative enrollment reduction of 20,543 patients (11%; 89 patients averaged equally over all studied trials) and an estimated cumulative cost savings of 851 million USD (3.7 million USD averaged equally over all studied trials). Bayesian interim analyses may improve randomized trial efficiency by reducing enrollment requirements without compromising trial interpretation. Increased utilization of Bayesian interim analysis has the potential to reduce costs of late-phase trials, reduce patient exposures to ineffective therapies, and accelerate approvals of effective therapies. Question: What are the effects of Bayesian early stopping rules on the efficiency of phase III randomized oncology trials?Findings: Individual-patient level outcomes were reconstructed for 184,752 patients from 230 trials. Compared with the original interim analysis strategy, in silico Bayesian interim analysis reduced patient enrollment requirements and preserved the original trial interpretation. Meaning: Bayesian interim analysis may improve the efficiency of conducting randomized trials, leading to reduced costs, reduced exposure of patients to disadvantageous treatments, and accelerated approval of efficacious therapies.

Preparation and properties of gel-type low-temperature phase change materials

In the context of the dual‑carbon target, there is a high emphasis on the energy efficiency of traditional mechanical cold storage systems with significant power consumption. Additionally, the implementation of time-of-use electricity pricing has played a crucial role in driving the rapid advancement of energy storage technology. The application of energy storage technology in cold storage can significantly reduce the energy consumption of the refrigeration system, save operating costs by shifting peak demand to valleys, and reduce start and stop frequencies. Therefore, studying phase-change materials with high latent heat, low cost, and good performance for cold storage is of great practical application in cold storage. The paper developed four types of gel-type phase-change cold storage materials with high latent heat, low cost, and good cycle stability. These materials mainly consist of NH4Cl, KCl, and deionized water. The phase transition temperature ranges from −18 to −21 °C, the latent heat of phase change is approximately 260 to 289 J/g, and the thermal conductivity ranges from 0.58 to 0.60 W/(m·K), which can meet the cooling demand of cold storage facilities. Furthermore, by comparing the phase transition temperature, latent heat value of phase change, and cyclic stability, a gel-type PCM with good comprehensive properties was selected for corrosion and corrosion inhibition studies with five common metal samples in welded and non-welded forms. The results showed that material B2 had slight corrosion on 1060 aluminum, 6061 aluminum, and 304 stainless steels, but no obvious corrosion phenomenon was found on 316 stainless steels. The corrosion rate of the material on red copper was the highest, and the corrosion was too strong. In addition, the corrosion of welded parts is more serious than that of non-welded parts, and the welding points are more susceptible to corrosion. Adding the corrosion inhibitor BTA to material B2 can reduce the corrosion rate of red copper by more than 94 %.

Research on Implementation of a PWM Generation Algorithm for Train Stationary Stopping Frequency

In industrial electronic equipment or communication equipment, a reference clock should be generated for stable operation of the equipment, which requires precise and stable reference frequency generation. As a method for generating this reference frequency, an analog method called PLL (phase locked-loop) has been devised and widely used. However, in order to make a more precise and stable reference frequency simple and economical, a DDS (direct digital synthesizer) has been developed. In this paper, we propose a stable and accurate method to generate a low frequency of the PWM method via pure logic circuit configuration without a microprocessor for digital reference frequency generation. Depending on the electronic communication equipment, the required reference frequency varies from a low frequency to a very high frequency. The reference frequency synthesis required in these frequency bands has been studied in various ways, but in industries such as railways, the low-frequency band based on the DDS method is used. In particular, it is very important to operate without a single operating error or failure in order to obtain information for stopping the train. Therefore, it is necessary to design a pure logic method that excludes a stored program type processor that minimizes the possibility of temporary interruption due to disturbance such as surge or high voltage. Therefore, through this study, the algorithm is implemented so that the duty ratio is output at 50:50, the circuit is configured so that two target frequencies are generated at the same time, and the performance is verified by generating the low-frequency band used for stopping the railway train. It was confirmed that the accuracy and stability were improved compared to the analog method used for stopping the railway train, and it was verified that the frequency resolution was superior to the similar results obtained in the digital frequency synthesis field so far.

(Invited) Ratchet Based Ion Pumps for Selective Ion Separations

Even though highly selective ion pumps are found in the membrane of every living cell, artificial ion selective separation is a longstanding unmet challenge in science and engineering. The development of a membrane-based ion separation technology can drive a dramatic progress in a wide range of applications such as: water treatment, bio-medical devices, extraction of precious metals from sea water, chemical sensors, solar fuels and more. In this contribution we report the experimental demonstration of ion pumps based on a electronic ratchet mechanism.Electronic ratchets are devices that utilize a temporal modulation of a spatially asymmetric electric field to drive steady state current. Like peristaltic pumps, where the pump mechanism is not in direct contact with the pumped fluid, electronic ratchets induce a net current with no direct charge transport between the power source and the pumped charge carriers. Thus, electronic ratchets can be used to pump ions in steady state with no electrochemical reactions between the power source and the pumped ions resulting in an 'all-electric' ion pump.Ratchet-based ion pumps (RBIPs) were fabricated by coating the two surfaces of nano-porous alumina wafers with gold, thus forming nano-porous capacitor-like devices. The electric field within the nano-pores is modulated by oscillating the capacitor voltage. Thus, when immersed in a solution, ions within the pores experience a modulating electric field resulting in ratchet-based ion pumping. The RBIPs performance was studied for various input signals, geometries, and solutions. RBIPs were shown to drive ionic current densities of several uA/cm^2 even when opposed by an electrostatic force. A significant ratchet action was observed with input signal amplitudes as low as 0.1V thus demonstrating that RBIPs can drive an ionic current with no associated redox reactions.An important hallmark of ratchets is the ability to invert the direction of particle flow with a change in the input signal frequency. The stopping frequency, which is the frequency at which the particle flux changes its direction, is determined by the potential distribution and particles transport properties. As a result, for a given ratchet, there can be a frequency at which particles with the same charge, but different diffusion coefficients, are transported in opposite directions. This concept, that was never applied to ion separations, can enable the extraction of ions with extremely low relative concentrations if their diffusion coefficient is even slightly different from the main ions in the solution. We show by simulation, that for the prevalent ions in water, ions with a relative diffusion coefficient difference as small as 1% can be driven to opposite directions with a velocity difference as high as 1.2 mm/s. Since the direction of ion transport is determined by the input signal frequency, the sorting properties can be tuned in real time providing a simple fit-to-purpose solution for a variety of ion separations applications. Figure 1

Single cell transcriptomics reveals UAR codon reassignment in Palmarella salina (Metopida, Armophorea) and confirms Armophorida belongs to APM clade

Anaerobes have emerged in several major lineages of ciliates, but the number of independent transitions to anaerobiosis among ciliates is unknown. The APM clade (Armophorea, Muranotrichea, Parablepharismea) represents the largest clade of obligate anaerobes among ciliates and contains free-living marine and freshwater representatives as well as gut endobionts of animals. The evolution of APM group has only recently started getting attention, and our knowledge on its phylogeny and genetics is still limited to a fraction of taxa. While ciliates portray a wide array of alternatives to the standard genetic code across numerous classes, the APM ciliates were considered to be the largest group using exclusively standard nuclear genetic code. In this study, we present a pan-ciliate phylogenomic analysis with emphasis on the APM clade, bringing the first phylogenomic analysis of the family Tropidoatractidae (Armophorea) and confirming the position of Armophorida within Armophorea. We include five newly sequenced single cell transcriptomes from marine, freshwater, and endobiotic APM ciliates – Palmarella salina, Anteclevelandella constricta, Nyctotherus sp., Caenomorpha medusula, and Thigmothrix strigosa. We report the first discovery of an alternative nuclear genetic code among APM ciliates, used by Palmarella salina (Tropidoatractidae, Armophorea), but not by its close relative, Tropidoatractus sp., and provide a comparative analysis of stop codon identity and frequency indicating the precedency to the UAG codon loss/reassignment over the UAA codon reassignment in the specific ancestor of Palmarella. Comparative genomic and proteomic studies of this group may help explain the constraints that underlie UAR stop-to-sense reassignment, the most frequent type of alternative nuclear genetic code, not only in ciliates, but eukaryotes in general.

Objective evaluation of voice quality by intermittent recording of sound on English voice

Continuous sound surveillance have the problem of unintentionally recording conversational content. On the other hand, if only coarse features are stored so that speech cannot be recovered, the use of the accumulated recorded information is very limited. In this study, we propose a method to record raw background sounds while making the conversational content inaudible by periodically repeating recording and stopping. In this presentation, we will show the results of an objective evaluation using a speech recognition model by varying the ratio of recording time and the recording stop frequency. The results showed that the recording time ratio can be maximized by selecting appropriate recording stop frequency even for the same objective voice quality.

Older adults exhibit declines in instrumental activities of daily living during a virtual grocery shopping task

Introduction: The successful performance of instrumental activities of daily living (IADLs) is critical in maintaining independence for older adults. Traditional IADL questionnaires and performance-based assessments are time consuming, potentially unreliable, and fail to adequately consider the interplay between cognitive and motor performance in completing IADLs. The Cleveland Clinic Virtual Reality Shopping (CC-VRS) platform was developed to objectively quantify IADL performance through the characterization of cognitive, motor, and cognitive-motor function. The CC-VRS combines an immersive virtual grocery store with an omnidirectional treadmill to create a scenario in which the user physically navigates through a virtual environment. The primary aim of this project was to determine the known-group validity of the CC-VRS platform to characterize IADL performance in healthy older adults and young adults.Methods: Twenty healthy young (n = 10) and older (n = 10) adults completed the Basic and Complex CC-VRS scenarios. Position data from VR trackers on the hands, waist, and feet were used to quantify motor performance. Cognitive and dual-task performance were automatically calculated by the application during specific shopping sub-tasks.Results: Older adults exhibited significantly worse performance on multiple cognitive, motor, and dual-task outcomes of the CC-VRS (e. g., average walking speed, number of list activations, and stopping frequency).Discussion: The CC-VRS successfully discriminated IADL performance between young and healthy older adults. The complex realistic environment of the CC-VRS, combined with simultaneous evaluation of motor and cognitive performance, has the potential to more accurately characterize IADL performance by identifying subtle functional deficits that may precede neurological disease.

Eco-Speed Harmonization with Partially Connected and Automated Traffic at an Isolated Intersection

This paper proposed an eco-speed harmonization method at intersections. It is able to reduce carbon emissions by controlling partially connected and automated traffic and signal timing. It has the following features: (i) traffic emission reduction enhancement at various demand levels; (ii) traffic emission achievement while improving the mobility of entire traffic at intersections; (iii) enhanced traffic emission reduction with the help of a small portion of connected and automated vehicles; and (iv) potential implementations in the near feature. To validate the effectiveness, the proposed method is evaluated against a state-of-the-art strategy. Sensitivity analysis is conducted under various demand levels and market penetration rates (MPRs) of connected and automated vehicles (CAVs). The result shows that the proposed method outperforms and has the benefits of traffic emission reduction, throughput improvement, and stop frequency reduction. The proposed method demonstrates consistent performance across all demand levels and CAVs’ MPR. The proposed approach can achieve a reduction in emissions ranging from 4% to 61%, an average increase in throughput of around 14.91%, and a decrease in the stop frequency of at least 26%. This provides the foundation for future CAVs-based eco-approaching strategies.

Polarization–Insensitive Angularly Stable Compact Triple Band Stop Frequency Selective Surface for Shielding Electromagnetic Radiations

Polarization–Insensitive Angularly Stable Compact Triple Band Stop Frequency Selective Surface for Shielding Electromagnetic Radiations

Trajectory of health care resources among adults stopping or reducing treatment frequency of botulinum toxin for chronic migraine treatment in Alberta, Canada.

Understand health resource, medication use, and cost of adults with chronic migraine who received guideline-recommended onabotulinumtoxinA (botulinum toxin) treatment frequency and then continued or reduced/stopped. Botulinum toxin may be a beneficial treatment for chronic migraine; the trajectory of health resources utilization among those with continued or reduced/stopped use is unclear. A retrospective population-based cohort study utilizing administrative data from Alberta, Canada (2012-2020), was performed. A cohort of adults who received ≥5 botulinum toxin treatment cycles for chronic migraine over 18 months (6-month run-in; 1-year pre-index period) were grouped into those who (1) continued use (≥3 treatments/year), or (2) stopped or reduced use (stopped for 6 months then received 0 or 1-2 treatments/year, respectively) over a 1-year post-index period. Health resources and medication use were described, and pre-post costs were assessed. A second cohort that received ≥3 treatments/year immediately followed by 1 year of stopped or reduced use was considered in sensitivity analysis. Pre-post health resource, medication use, and costs were similar among those with continued use (n = 3336). Among those who stopped or reduced use (n = 1099; 756 stopped, 343 reduced), health resource, medication use, and costs were lower in the post- (total median per-person cost [IQR]: all-cause $4851 [$8090]; migraine-related $835 [$1915]) versus pre- (all-cause $6096 [$7207]; migraine-related $2995 [$1950]) index period (estimated cost ratios [95% CI]: total all-cause 0.86 [0.79, 0.95]; total migraine-related 0.44 [0.40, 0.48]). In the second cohort (n = 3763), return to continued use (≥3 treatments/year) occurred in up to 70.4% in those with reduced use. Of adults treated with botulinum toxin for chronic migraine, 75.2% had continued use, stable health resource and medication use, and costs over a 2 year period. In those that stopped/reduced use, the observed lower health resource and migraine medication use may indicate improved symptom control, but the resumption of guideline-recommended treatment intervals after reduced use was common.

Determination of Organic Acids in Cucumber Leaves by Solid Phase Extraction–Electrospray Ionization–Ion Mobility Spectrometry (SPE-ESI-IMS)

A solid phase extraction-electrospray ionization-ion mobility spectrometry (SPE-ESI-IMS) method was developed to determine six organic acids in cucumber leaves. The multiplexing IMS using correlation technique was adopted to optimize the signal-to-noise ratio (SNR) and resolution. 90% methanol/water was selected to be the solvent, the flow rate was 120 µL·h−1, the stop frequency of ion gate was 5000 Hz, the ion gate opening period was 0.1 ms, the air flow velocity was 2.0 L·min−1, the electrospray voltage was 3.5 kV, and the drift tube temperature was 90 °C. The cucumber leaves were treated with ultrasound in 50% methanol/water. The analytes were subsequently eluted from an SPE cartridge with 0.1 mol·L−1 HCl, and the extract was neutralized to pH 2–3 with ammonia before freeze-drying. SPE-ESI-IMS enabled the effective determination of citric acid, fumaric acid, lactic acid, malic acid, pyruvic acid, and succinic acid based upon the drift time. The limits of detection were from 0.008 µg·mL−1 to 0.2 µg·mL−1, and the recoveries of spiked samples were from 87.00% to 107.20%. The convenient, sensitive, and efficient developed SPE-ESI-IMS method may be applicable for the determination of organic acids in leaves.

Statistical study of type III bursts and associated HXR emissions

Context. Flare-accelerated electrons may produce closely temporarily related hard X-ray (HXR) emission while interacting with the dense solar atmosphere and radio type III bursts when propagating from the low corona to the interplanetary medium. The link between these emissions has been studied in previous studies. We present here new results on the correlation between the number and spectrum of HXR-producing electrons and the type III characteristics (flux, starting frequency). Aims. The aim of this study is to extend the results from previous statistical studies of radio type III bursts and associated HXR emissions: in particular, to determine what kind of correlation, if any, exists between the HXR-emitting electron numbers and the radio flux, as well as whether any correlations between the electron numbers or energy spectra are deduced from associated HXR emissions and type III starting (stopping) frequencies. Methods. This study is based on thirteen years of data between 2002 and 2014. We shortlisted ≃200 events with a close temporal association between HXR emissions and radio type III bursts in the 450–150 MHz range. We used X-ray flare observations from RHESSI and Fermi/GBM to calculate the number of electrons giving rise to the observed X-ray flux and observations from the Nançay Radioheliograph to calculate the peak radio flux at different frequencies in the 450–150 MHz range. Under the assumption of thick-target emissions, the number of HXR-producing electrons and their energy spectra were computed. The correlation between electron numbers, power-law indices, and the peak radio fluxes at different frequencies were analysed as well as potential correlations between the electron numbers and starting frequency of the radio burst. Bootstrap analysis for the correlation coefficients was performed to quantify the statistical significance of the fit. Results. The correlation between the number of HXR electrons and the peak flux of the type III emission decreases with increasing frequency. This correlation is larger when considering the electron number above 20 keV rather than the electron number above 10 keV. A weak anti-correlation is also found between the absolute value of the electron spectral index and the peak radio flux at 228 MHz. A rough correlation is found between the HXR-producing electron number above 20 keV and the type III starting frequency. This correlation is smaller if the electron number above 10 keV is considered. All the results are discussed in the framework of results from previous studies and in the context of numerical simulations of bump-in-tail instabilities and subsequent radio emissions.

Collaborative optimization for train stop planning and train timetabling on high-speed railways based on passenger demand.

In recent years, with increasing passenger travel demand, high-speed railways have developed rapidly. The stop planning and timetabling problems are the core contents of high-speed railway transport planning and have important practical significance for improving efficiency of passenger travel and railway operation Dong et al. (2020). This study proposes a collaborative optimization approach that can be divided into two phases. In the first phase, a mixed-integer nonlinear programming model is constructed to obtain a stop plan by minimizing the total passenger travel time. The constraints of passenger origin-destination (OD) demand, train capacity, and stop frequency are considered in the first phase. In the second phase, the train timetable is optimized after the stop plan is obtained. A multiobjective mixed-integer linear optimization model is formulated by minimizing the total train travel time and the deviation between the expected and actual departure times from the origin station for all trains. Multiple types of trains and more refined headways are considered in the timetabling model. Finally, the approach is applied to China's high-speed railway, and the GUROBI optimizer is used to solve the models in the above two stages. By analyzing the results, the total passenger travel time and train travel time decreased by 2.81% and 3.34% respectively. The proposed method generates a more efficient solution for the railway system.

Hierarchical re-entrant honeycomb metamaterial for energy absorption and vibration insulation

A novel hierarchical re-entrant honeycomb metamaterial is proposed by integrating the re-entrant honeycomb (RH) with square unit cell and named as square re-entrant honeycomb (SRH). The novel hierarchical re-entrant honeycomb can not only improve energy absorption capacity but also present better vibration insulation compared with traditional RH structure. Dynamic crushing behaviors of the SRH structures are investigated theoretically and numerically. The theoretical plateau stress is in good agreement with the numerical plateau stress. Meanwhile, the deformation modes and energy absorption capacity of RH and square re-entrant honeycombs (SRHs) are compared under different impact velocities. The results show that the plateau stress and the specific energy absorption (SEA) of SRHs is higher than RH. Moreover, the vibration isolation capability of the SRHs is studied using finite element analysis. In particular, the introduction of square unit cells expand the band gap, especially in the low frequency range. By adjusting the size of oscillators, the starting and stopping frequencies of band gaps are lower effectively and the number of band gaps is increased. The results indicate that the introduction of the mass inclusions can improve the band gap characteristics of the SRH, which produce local resonance effect and the local resonance type band gap. It also appears multiple band gaps at the same time. In addition, the introduction of the mass inclusions also improves the SEA of the SRH under high-velocity crushing. This work may benefit structural vibration isolation and protection design, which provides a new thought for design and development of advanced multi-functional composite structures and materials in the engineering.

Association of Antipsychotic-Related Weight Gain With Treatment Adherence and Switching Using Electronic Medical Records Data.

Objective: To leverage electronic health record (EHR) data to explore the relationship between weight gain and antipsychotic adherence among patients with schizophrenia and bipolar disorder (BD). Methods: EHR data were used to identify individuals with at least 60 days of continuous antipsychotic use between 2005 and 2019. Patients were diagnosed with schizophrenia, schizoaffective disorder, BD, or neither diagnosis (psychiatric controls). We examined the association of weight gain in the first 90 days with the proportion of days covered (PDC) with an antipsychotic and with the frequency of medication switching or stopping. Results: We identified 590 adults with schizophrenia or schizoaffective disorder, 819 adults with BD, and 642 psychiatric controls. In the first 90 days, the percentages of patients with a PDC ≥ 0.80 were 76.8% (schizophrenia), 77.1% (BD), and 70.7% (controls). Logistic regression models revealed that weight gain of ≥ 7% trended toward being significantly associated with greater adherence in the first 90 days (odds ratio = 1.29, P = .077) and was significantly associated with an increased likelihood of a medication switch in the first 180 days (odds ratio = 1.60, P = .003). Discussion: Patients whose weight increased by 7% or more in the first 90 days were more adherent but were also more likely to switch medications during the first 180 days.

Accounting for Heterogeneity in Stop Frequency Models of Work Tours Using Latent Class Poisson Models

Stop frequency models, as one of the elements of activity based models, represent an important part of travel behavior. Unobserved heterogeneity across the travelers should be taken into consideration to prevent biasedness and inconsistency in the estimated parameters in the stop frequency models. Additionally, previous studies on the stop frequency have mostly been done in larger metropolitan areas and less attention has been paid to the areas with less population. This study addresses these gaps by using 2012 travel data from a medium sized U.S. urban area using the work tour for the case study. Stop in the work tour were classified into three groups of outbound leg, work based subtour, and inbound leg of the commutes. Latent Class Poisson Regression Models were used to analyze the data. The results indicate the presence of heterogeneity across the commuters. Using latent class models significantly improves the predictive power of the models compared to regular one class Poisson regression models. In contrast to one class Poisson models, gender becomes insignificant in predicting the number of tours when unobserved heterogeneity is accounted for. The commuters are associated with increased stops on their work based subtour when the employment density of service-related occupations increases in their work zone, but employment density of retail employment does not significantly contribute to the stop making likelihood of the commuters. Additionally, an increase in the number of work tours was associated with fewer stops on the inbound leg of the commute. The results of this study suggest the consideration of unobserved heterogeneity in the stop frequency models and help transportation agencies and policy makers make better inferences from such models.

The Impact of Socio-Economic, Land Use, and Travel Related Variables on Escort and Non-Escort Intermediate Stops on Work Tours

Stop frequency prediction model is one of the components of the activity-based travel demand models. Most of the previous studies have considered stops during commutes regardless of their purposes. This approach does not yield the contribution of the explanatory variables to the likelihood of making stops of different purposes. Besides, most of the former studies have been conducted in larger metropolitan areas. This study attempts to cover these gaps by using 2012 travel data of Fargo-Moorhead medium-sized US metropolitan area and classifying stops on work tours into escort, non-escort, and a combination of all stops. The results of logit models indicate that personal characteristics of the commuters do not contribute to the escort stop participation likelihood. In addition, household size variables have a large impact on the likelihood of participating in escort stops and participating in the combined stops on the outbound leg of the commutes. Contrary to several previous studies, the significance and sign of the coefficient of income level vary for different stop purposes. Commuters seemed to be more likely to make more than one non-escort stop close to their workplace on the outbound legs of their commutes. The general results suggest separating the stop purposes yields more illustrative results rather than using one model for the combined stops.

Evaluation of an assistance system supporting older pedestrians' road crossing in virtual reality and in a real-world field test.

Older pedestrians are at a high risk of becoming victims of car accidents because they tend not to pay sufficient attention to upcoming traffic. Within our research project, an assistance system for older pedestrians has been developed. It detects the street and communicates with the users through a vibrotactile interface. Two evaluation studies have been carried out in order to understand the potential benefits and drawbacks of the developed assistance system. One study was conducted in a virtual environment (VR) with 23 participants, aged 65+. The other experiment was a field test in a real street environment with 26 participants, aged 65+. Objective dependent variables in both experiments were checking for traffic (operationalized via head tracking) and stopping in front of the street (VR study), i.e., approaching time (field test). Workload and acceptance served as subjective dependent variables. Analysis of the VR experiment showed significantly more head rotation with the assistance system than without it, as well as significantly more with cars than without cars. The same was true for the frequency of stopping. No significant difference was found concerning workload. With regard to acceptance, the majority of participants indicated that the system was supportive and able to reduce risks in traffic. In the field test, results for head rotation confirmed the findings of the VR study. Analysis showed a marginally significant higher head rotation frequency with the alarm system than without, and significantly different patterns of checking for traffic at marked and unmarked crossings. However, unlike in the VR study, no differences were found in approaching time with and without the assistance system. Approaching time was slower at marked crossings. No difference was found with regard to workload, meaning the use of the assistance system did not increase the subjectively perceived workload of participants. Analysis of the acceptance questionnaire showed a positive attachment to the assistance system. However, most reported that they did not experience any advantage from the use of the system, and expressed no intention to buy such a system for themselves.

Highly Angularly Stable Dual-Band Stop FSS for Blocking Satellite Downlink Frequencies

High angular stability dual-band (C- and X-band) stop frequency selective surface based spatial filter is proposed in this article for blocking the satellite downlink frequencies. The unit cell of the structure consists of vertical and horizontal dipoles having two folded arms. The transmission coefficient of the filter in the designated satellite frequency bands, i.e., 3.7–4.2 GHz and 7.25–7.75 GHz has been obtained less than −10 dB. The current distribution and the equivalent circuit model of the unit cell have been illustrated to explain the resonance behavior and response of the filter. The proposed structure gives a stable response up to 85° of oblique incidence for both TE and TM polarizations. A prototype of the proposed structure has been fabricated, experimentally tested, and validated with simulation results.