The impact of mid-block crossing on urban arterial operational characteristics using multimodal microscopic simulation approach

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

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Virus Transmission Risk in Urban Rail Systems: Microscopic Simulation-Based Analysis of Spatio-Temporal Characteristics

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211010181 ◽

2021 ◽

pp. 036119812110101

Author(s):

Jiali Zhou ◽

Haris N. Koutsopoulos

Keyword(s):

Public Transportation ◽

Virus Transmission ◽

Flow Characteristics ◽

Transportation Systems ◽

Transmission Risk ◽

Microscopic Simulation ◽

Spatial And Temporal Patterns ◽

Subway System ◽

Public Transportation Systems ◽

The Impact

The transmission risk of airborne diseases in public transportation systems is a concern. This paper proposes a modified Wells-Riley model for risk analysis in public transportation systems to capture the passenger flow characteristics, including spatial and temporal patterns, in the number of boarding and alighting passengers, and in number of infectors. The model is used to assess overall risk as a function of origin–destination flows, actual operations, and factors such as mask-wearing and ventilation. The model is integrated with a microscopic simulation model of subway operations (SimMETRO). Using actual data from a subway system, a case study explores the impact of different factors on transmission risk, including mask-wearing, ventilation rates, infectiousness levels of disease, and carrier rates. In general, mask-wearing and ventilation are effective under various demand levels, infectiousness levels, and carrier rates. Mask-wearing is more effective in mitigating risks. Impacts from operations and service frequency are also evaluated, emphasizing the importance of maintaining reliable, frequent operations in lowering transmission risks. Risk spatial patterns are also explored, highlighting locations of higher risk.

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A Novel Design of Landing Gear Oleo Strut Damper Using MR Fluid for Aircraft and UAV’s

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.225.275 ◽

2012 ◽

Vol 225 ◽

pp. 275-280

Author(s):

Chandra B. Asthana ◽

Rama B. Bhat

Keyword(s):

Shock Absorber ◽

Fluid Viscosity ◽

Simulation Approach ◽

Body Frame ◽

Mr Fluid ◽

Orifice Area ◽

Aerial Vehicle ◽

Impact Kinetic Energy ◽

The Impact ◽

Novel Design

Most landing gears used in aircraft employ very efficient oleo-pneumatic dampers to absorb and dissipate the impact kinetic energy of the aircraft body frame. A single-acting shock absorber is most commonly used in the oleo strut that has a metering pin extending through the orifice, which can vary the orifice area upon compression and extension of the strut. This variation is adjusted by shaping the metering pin so that the strut load is fairly constant under dynamic loading. In this paper, it is proposed to further change the damping coefficient as a function of time in order to achieve a semi-active control of the aircraft vibrations during landing by using Magnetorheological (MR) fluid in the Oleo. With the metering pin designed for a nominal flight condition, further variation in the fluid viscosity would help achieve the optimal performance in off-nominal flight conditions. A simulation approach is employed to show the effect of different profiles for viscosity variation in the MR fluid. The utility of such a damper can be very well exploited to include different criteria such as the landing distance after touchdown. This type of system can be used also in Unmanned Aerial Vehicle (UAV) application where the focus of design may be to accomplish the task without the consideration of passenger comfort.

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Parameter Sensitivity Analysis of a Cooperative Dynamic Bus Lane System With Connected Vehicles

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211035758 ◽

2021 ◽

pp. 036119812110357

Author(s):

Meng Xie ◽

Michael Winsor ◽

Tao Ma ◽

Andreas Rau ◽

Fritz Busch ◽

...

Keyword(s):

Travel Time ◽

Transition Period ◽

Penetration Rate ◽

Simulation Models ◽

Driving Behavior ◽

Connected Vehicles ◽

Microscopic Simulation ◽

Communication Range ◽

Bus Lane ◽

The Impact

This paper aims to evaluate the sensitivity of the proposed cooperative dynamic bus lane system with microscopic traffic simulation models. The system creates a flexible bus priority lane that is only activated on demand at an appropriate time with advanced information and communication technologies, which can maximize the use of road space. A decentralized multi-lane cooperative algorithm is developed and implemented in a microscopic simulation environment to coordinate lane changing, gap acceptance, and car-following driving behavior for the connected vehicles (CVs) on the bus lane and the adjacent lanes. The key parameters for the sensitivity study include the penetration rate and communication range of CVs, considering the transition period and gradual uptake of CVs. Multiple scenarios are developed and compared to analyze the impact of key parameters on the system’s performance, such as total saved travel time of all passengers and travel time variation among buses and private vehicles. The microscopic simulation models showed that the cooperative dynamic bus lane system is significantly sensitive to the variations of the penetration rate and the communication range in a congested traffic state. With a CV system and a communication range of 150 m, buses obtain maximum benefits with minimal impacts on private vehicles in the study simulation. The safety concerns induced by cooperative driving behavior are also discussed in this paper.

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The New Regulator in Town: The Effect of Walmart's Sustainability Mandate on Supplier Shareholder Value

Journal of Marketing ◽

10.1509/jm.16.0276 ◽

2018 ◽

Vol 82 (2) ◽

pp. 124-141 ◽

Cited By ~ 13

Author(s):

Katrijn Gielens ◽

Inge Geyskens ◽

Barbara Deleersnyder ◽

Max Nohe

Keyword(s):

Brand Equity ◽

Shareholder Value ◽

Abnormal Returns ◽

Short Term ◽

Power Sources ◽

Expert Power ◽

Operational Characteristics ◽

Countervailing Power ◽

Cost Efficient ◽

The Impact

Suppliers are increasingly being forced by dominant retailers to clean up their supply chains. These retailers argue that their sustainability mandates may translate into profits for suppliers, but many suppliers are cynical about these mandates because the onus to undertake the required investments is on them while potential gains may be usurped by the mandating retailer. We examine whether supplier fears are justified by studying the impact of Walmart's sustainability mandate on its suppliers’ (short-term) shareholder value. Although about two-thirds of suppliers are indeed financially harmed, approximately one-third benefit. To delve deeper into this variation, we relate suppliers’ short-term abnormal returns to Walmart's appropriation power and explore whether and to what extent a supplier's referent and expert power sources, derived from its marketing and operational characteristics, respectively, can counteract Walmart's appropriation attempts. We find that the supplier's marketing characteristics (its environmental reputation, brand equity, and advertising) provide it with the countervailing power needed to resist Walmart's appropriation attempts. In contrast, cost-efficient suppliers and suppliers that invest heavily in R&D have more difficulty withstanding Walmart's squeeze attempts.

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Mechatronic System’s Permeable Materials with Controlled Porosity

Journal of Engineering Sciences ◽

10.21272/jes.2021.8(1).c6 ◽

2021 ◽

Vol 8 (1) ◽

pp. C45-C49

Author(s):

O. Povstyanoy ◽

A. MacMillan

Keyword(s):

Process Equipment ◽

Mechatronic System ◽

Porosity Distribution ◽

Operational Characteristics ◽

Controlled Porosity ◽

Permeable Powder Material ◽

Design And Manufacture ◽

The Impact ◽

Technical Products

Up-to-date directions in the development of modern industry increase the requirements for the quality of technical products. The design and manufacture of competitive process equipment require accuracy, productivity, and efficiency. Therefore, in this article, a new mechatronic system has been designed and developed to help porous, permeable materials with predicted porosity have been produced. The research aims to develop a mechatronic system for technology optimization in manufacturing permeable porous materials with controlled properties. As a result, the method of computer modeling of porous, permeable materials was developed. It allows us to consider the peculiarities of porosity distribution and radial velocity in radial isostatic compression. Additionally, a new mechatronic system for producing permeable materials allows us to determine the porosity distribution and particular characteristics of permeable powder material. The proposed approach allows us to evaluate the impact of technological modes on the main operational characteristics.

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The impact of nonresponse in different survey stages on the precision of prevalence estimates for multi-stage survey studies

BMC Research Notes ◽

10.1186/s13104-021-05840-0 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Ming Ma ◽

Sophie Rosenberg ◽

Alexander M. Kaizer

Keyword(s):

Survey Research ◽

State Level ◽

Simulation Approach ◽

Multi Stage ◽

Margin Of Error ◽

Prevalence Estimates ◽

Three Stages ◽

Nonresponse Rate ◽

The Mean ◽

The Impact

Abstract Objective While it is known that nonresponse might produce biased results and impair the precision of results in survey research studies, the pattern of the impact on the precision of estimates due to the nonresponse in different survey stages is historically overlooked. Having this type of information is essential when creating recruitment plans. This study proposes to examine and compare the effect of nonresponse in different stages on the precision of prevalence estimates in multi-stage survey studies. Based on data from a state level survey, a simulation approach was used to generate datasets with different nonresponse rates in three stages. The margin of error was then compared between the datasets with nonresponse at three different survey stages for 12 outcomes. Results At the same nonresponse rate, the mean margin of error was greater for the data with nonresponse at higher stages. Additionally, as the nonresponse rate increased, precision was more inflated within the data with higher stage nonresponse. This suggests that the effort used to recruit the primary sampling units is more crucial to improve the precision of estimates in multi-stage survey studies.

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Measuring Market Risk of Commercial Banks Implementing VaR with Historical Simulation Approach

10.47260/jafb/1144 ◽

2021 ◽

pp. 79-99

Author(s):

Minhaz-Ul Haq

Keyword(s):

Stock Prices ◽

Commercial Banks ◽

Value At Risk ◽

First Generation ◽

Market Risk ◽

Jel Classification ◽

Simulation Approach ◽

Share Prices ◽

Historical Simulation ◽

The Impact

This paper attempts to picture the impact of the market risk of ten commercial banks located in Bangladesh with the help of a non-parametric model known as the Historical Simulation Approach over the course of eight years. These banks' daily stock prices were used as inputs and analyzed in Microsoft Excel by means of Percentile and LN function. The study revealed market risk exposure as third, second-and first-generation banks from the least to the highest. It also pointed out the ups and downs of these banks' share prices in the selected period. Further analysis showed the portfolio VaR estimation for different time intervals. JEL classification numbers: G32. Keywords: Value-at-risk, Historical Simulation, Market Risk, Confidence Interval.

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