Computing the Minimal U-Turn Offset for an Unsignalized Superstreet

2017 ◽  
Vol 2618 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Liu Xu ◽  
Xianfeng Yang ◽  
Gang-Len Chang
Keyword(s):  
Safety Assessment ◽  
Critical Role ◽  
Geometric Design ◽  
Safety Performance ◽  
Assessment Model ◽  
Traffic Dynamics ◽  
Convenient Tool ◽  
Proposed Model ◽  
Different Levels

Despite the extensive implementations of unsignalized superstreets in practice, reliable methodologies for their geometric design remain unavailable. In recognition of the critical role of the U-turn offset length design, this study proposed an applicable tool to help traffic professionals determine the minimum required offset length for safety needs. The proposed model offers a convenient tool to evaluate a candidate design on the basis of traffic dynamics and driver gap acceptance behavior. In addition, this model can be used to assess whether installation of signals is needed to accommodate growing traffic. With the use of the surrogate safety assessment model as an unbiased tool, this study evaluated the safety performance of one superstreet with varied U-turn offset lengths (i.e., 700, 1,100, and 1,500 ft). Comparisons of the results of different designs indicated that the safety performance of the superstreet would not be compromised if the U-turn offset was reduced from 1,500 to 1,100 ft. However, more severe crashes were observed when the U-turn offset length was 700 ft. Further extensive analyses on different levels of demand also confirmed the need to properly design the offset length in an unsignalized superstreet.

Critical Role of Supply Chain Decoupling Point in Mass Customisation from Its Upstream and Downstream Information Systems Point of View

2011 ◽  
pp. 185-196
Author(s):  
S. Saghiri
Keyword(s):  
Supply Chain ◽  
Information Systems ◽  
Critical Role ◽  
Point Of View ◽  
Information Flows ◽  
Mass Customisation ◽  
Different Types ◽  
Type Information ◽  
Different Levels

Concentrating on the role of supply chain decoupling point, this chapter introduces different levels of customisation and mass operations and three types of mass customisation. It argues that in each mass customisation type, information systems which are upstream and downstream of the decoupling point can be varied. Consequently, information flows in different types of mass customisation have been examined. This analysis is an endeavour to organise mass customisation information systems across the supply chain, while it can be a useful structure for future researches in this area as well.

Collaborative Market Making

2019 ◽  
pp. 287-312
Author(s):  
Pinar Ozcan ◽  
Kerem Gurses
Keyword(s):  
Critical Role ◽  
Future Research ◽  
Extensive Discussion ◽  
New Markets ◽  
Regulatory Uncertainty ◽  
Market Formation ◽  
Potential Impact ◽  
Interfirm Alliances ◽  
Different Levels

Extant work has identified many aspects of market formation including the mechanisms and processes associated with the origins of new markets and the trajectories of market emergence. However, the critical role of interfirm alliances in the formation of new markets still remains unexplored. This chapter brings forward interfirm alliances as a critical tool for firms to fuel the formation of new markets, which are often characterized by high levels of demand, supply, and regulatory uncertainty. To take a systematic look at the role of alliances in market formation, the chapter first describes the different alliance forms under the general categories of dyadic and multipartner alliances. Within these categories, the chapter discusses the potential impact of the respective alliance type on reducing different levels of uncertainty and catalyzing market emergence. It also provides an extensive discussion of the challenges that firms typically face within each type of alliance with regards to market formation. The chapter concludes with directions for future research in exploring alliances as tools for market formation.

Effect of different levels of bacterial probiotic on broilers performance

2003 ◽  
Vol 2003 ◽  
pp. 185-185
Author(s):  
M. R. Abdollahi ◽  
A. Kamyab ◽  
A. Bazzazzadekan ◽  
A. Nik-Khah ◽  
A. Z. Shahneh
Keyword(s):  
Alimentary Tract ◽  
Management Practices ◽  
Animal Health ◽  
Critical Role ◽  
Microbial Populations ◽  
Feed Management ◽  
Induced Changes ◽  
Symbiotic Organisms ◽  
Different Levels

The microbial populations in the gastrointestinal tracts of poultry play a key role in normal digestive processes and in maintaining animal health. Disease- and stress-induced changes in the physicochemical environment in the gastrointestinal tract, or simple changes in feed management practices can significantly influence the microbial populations and their effects on animal performance and health. In the last five decades, increased knowledge of the factors that influence the activities of microorganisms in the alimentary tract has helped to define the critical role of these symbiotic organisms. Probiotics, competitive exclusion and direct-fed microbial feed supplements can be used as a strategic tool for managing these microbial populations. The aim of this trial was study of effect of different levels of bacterial probiotic on broilers performance and some of blood factors.

scholarly journals Ground Risk Assessment of UAV Operations Based on Horizontal Distance Estimation under Uncertain Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yang Liu ◽  
Xuejun Zhang ◽  
Zhi Wang ◽  
Ziang Gao ◽  
Chang Liu
Keyword(s):  
Drag Force ◽  
Safety Assessment ◽  
Local Population ◽  
Assessment Model ◽  
Flying Height ◽  
Weather Data ◽  
Horizontal Distance ◽  
Proposed Model ◽  
Failure Point ◽  
The Impact

In this paper a ground safety assessment model is introduced based on the probability estimation of possible impact positions when unmanned aerial vehicle (UAV) crashes on the ground. By incorporating the random uncertainties during the descending process, risks associated with UAV’s ground crash are estimated accurately. The number of victims on the ground per flight hour is selected as the indicative index to evaluate the risk levels of the corresponding ground area. We mainly focus on the analysis of uncertainties that usually appear in drag coefficient which would generate a great amount of effects on the travelled horizontal distance from the failure point to the impact point on the ground, which further influences the possible impact positions. The drag force in the air, failure velocity of a UAV, and wind effects in the local area are all considered in the proposed model, as well as ground features, including sheltering effects on the ground, UAV parameter settings, and distribution of local population. Uncertainties in drag force when a UAV descends, UAV’s initial horizontal and vertical speeds at failure point, and local wind patterns are all considered as the indispensable factors in the proposed model. Especially the probability of fatality once hit by the UAV’s debris is explored to make the safety assessment more reliable and valuable. In the end, the actual UAV parameters and official historical weather data are used to estimate the risks in a real operation environment when a failure event happens at a legal flying height. Experimental results are given based on different types of UAVs and random effects in the descent. The results show that all the operations of all kinds of UAVs selected in the validation are so dangerous that the safety of people on the ground cannot be guaranteed, whose value is much bigger than the manned aircraft safety criterion 10−7.

scholarly journals Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation

2021 ◽  
Vol 13 (16) ◽  
pp. 8810
Author(s):  
Tullio Giuffrè ◽  
Anna Granà ◽  
Salvatore Trubia
Keyword(s):  
Autonomous Vehicles ◽  
Safety Assessment ◽  
Safety Evaluation ◽  
Simulation Models ◽  
Safety Performance ◽  
Assessment Model ◽  
Crash Data ◽  
Vehicle Trajectories ◽  
Traffic Conflicts ◽  
Surrogate Measures

The paper presents a microsimulation approach for assessing the safety performance of turbo-roundabouts where Cooperative Autonomous Vehicles “CAVs” have been introduced into the traffic mix alongside conventional vehicles “CVs”. Based on the analysis of vehicle trajectories from VISSIM and subsequent analysis of traffic conflicts through the Surrogate Safety Assessment Model (SSAM), the research aims to evaluate the safety benefits of turbo-roundabouts where the lanes are physically separated by raised curbs, compared to roundabouts without such curbs. The paper will then describe the methodological path followed to build VISSIM models of turbo-roundabouts with and without raised curbs in order to calibrate the simulation models and estimate the potential conflicts when a higher percentage of CAVs are introduced into the traffic mix. A criterion has been also proposed for setting properly the principal SSAM filters. The results confirmed both higher safety levels for turbo-roundabouts equipped with raised lane dividers compared to turbo-roundabout solutions without curbs, and better safety conditions under the traffic mix of CVs and CAVs. Therefore, it follows that, in absence of crash data including CAVs, the surrogate measures of safety are the only approach in which the safety performance of any roundabout or road entity can be evaluated.

Introduction of the Assessment Model of Nuclear Safety Culture

2014 ◽  
Vol 986-987 ◽  
pp. 334-338
Author(s):  
Jia Xu Zuo ◽  
Xu Xu ◽  
Jian She Chai ◽  
Chun Ming Zhang ◽  
Jian Ping Jing
Keyword(s):  
Safety Culture ◽  
Safety Assessment ◽  
External Environment ◽  
Nuclear Safety ◽  
Integrated System ◽  
Assessment Model ◽  
Fukushima Accident ◽  
Long Time ◽  
Environment Parameters ◽  
Different Levels

The nuclear safety became the more important after the Fukushima accident. The development of nuclear safety culture is one of the most effective methods to improve the safety. Also the assessment shows the level of the nuclear safety culture. The nuclear safety assessment model is described. The assessment model was described from its time and space, and it was also discussed from macro and micro levels. The internal and external environment parameters are considered and the assessment of different levels of safety culture is described. According to established principles of nuclear safety culture, the selection rules of the different levels evaluation indicators of nuclear safety culture are discussed too. And it is pointed that the assessment of nuclear safety culture is a long time project and an integrated system.

Let it flow: the role of seamlessness and the optimal experience on consumer word of mouth in omnichannel marketing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Paula Rodríguez-Torrico ◽  
Rebeca San José Cabezudo ◽  
Sonia San-Martín ◽  
Lauren Trabold Apadula
Keyword(s):  
Subjective Experience ◽  
Word Of Mouth ◽  
Critical Role ◽  
Flow State ◽  
Content Type ◽  
Mediation Analyses ◽  
Proposed Model ◽  
Shopping Experience ◽  
Positive Direct

PurposeOmnichannel consumers are more proactive, engage in longer shopping journeys and share their experiences. However, their postpurchase behavioral responses remain understudied. This paper aims to examine how a seamless omnichannel environment can contribute to a more optimal shopping experience (flow state) and the subsequent impact on the likelihood of generating mixed (positive and negative) word of mouth (WOM).Design/methodology/approachA controlled experiment was conducted with 220 participants to test the proposed model based on the stimulus–organism–response (S-O-R) model and flow theory. The authors conducted an analysis of variance, two regression analyses and two mediation analyses to test the hypotheses.FindingsThe results confirm a positive direct effect of a seamless environment on consumers' flow state and a positive (negative) direct impact of flow on the likelihood of generating positive (negative) WOM. Additionally, the results suggest that flow mediates the effect of a seamless environment on WOM.Originality/valueThis study contributes to omnichannel and WOM literature by exploring the critical role of seamlessness in consumers' subjective experience (flow state) and postpurchase behaviors (mixed WOM). In conjunction with the relevant theoretical contributions, these findings also offer guidelines for practitioners to manage the seamless environment and mixed WOM in the omnichannel context.

scholarly journals Evaluation of Roundabout Safety Performance through Surrogate Safety Measures from Microsimulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Orazio Giuffrè ◽  
Anna Granà ◽  
Maria Luisa Tumminello ◽  
Tullio Giuffrè ◽  
Salvatore Trubia ◽  
...  
Keyword(s):  
Prediction Model ◽  
Safety Assessment ◽  
Traffic Volume ◽  
Safety Performance ◽  
Assessment Model ◽  
Model Framework ◽  
Safety Measures ◽  
Crash Prediction ◽  
Crash Prediction Model ◽  
Surrogate Safety Measures

The paper presents a microsimulation-based approach for roundabout safety performance evaluation. Based on a sample of Slovenian roundabouts, the vehicle trajectories exported from AIMSUN and VISSIM were used to estimate traffic conflicts using the Surrogate Safety Assessment Model (SSAM). AIMSUN and VISSIM were calibrated for single-lane, double-lane and turbo roundabouts using the corresponding empirical capacity function which included critical and follow-up headways estimated through meta-analysis. Based on calibration of the microsimulation models, a crash prediction model from simulated peak hour conflicts for a sample of Slovenian roundabouts was developed. A generalized linear model framework was used to estimate the prediction model based on field collected crash data for 26 existing roundabouts across the country. Peak hour traffic distribution was simulated with AIMSUN, and peak hour conflicts were then estimated with the SSAM applying the filters identified by calibrating AIMSUN and VISSIM. The crash prediction model was based on the assumption that the crashes per year are a function of peak hour conflicts, the ratio of peak hour traffic volume to average daily traffic volume and the roundabout outer diameter. Goodness-of-fit criteria highlighted how well the model fitted the set of observations also better than the SSAM predictive model. The results highlighted that the safety assessment of any road unit may rely on surrogate safety measures, but it strongly depends on microscopic traffic simulation model used.

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