scholarly journals Multi-Objective Evaluation Model of Single-Lane Roundabouts

2021 ◽  
pp. 036119812110114
Author(s):  
Hend Ahmed ◽  
Said M. Easa
Keyword(s):  
Environmental Sustainability ◽  
Evaluation Model ◽  
Objective Evaluation ◽  
Design Guidelines ◽  
Geometric Design ◽  
Specific Power ◽  
Design Elements ◽  
Multi Objective ◽  
Proposed Model ◽  
Comparison Results

Mobility, safety, and environmental sustainability are priorities in the geometric design of roundabouts. This paper presents a multi-objective optimization model that determines the geometric design elements of single-lane roundabouts using all three objectives. The user can specify weights for the objectives, or the model can determine the optimal weights. Mobility is defined in terms of roundabout delay and modeled using the United Kingdom empirical model. Safety is modeled in terms of collision frequency based on the methodology of the Highway Safety Manual. Environmental sustainability is represented by vehicle emissions (nitrogen oxides, hydrocarbons, carbon dioxide, and carbon monoxide) and is modeled using the vehicle-specific power methodology. The proposed model directly identifies the optimal geometric dimensions (decision variables) of the roundabout, including entry width, exit width, approach half-width, circulatory width, effective flare length, entry radius, entry angle, and inscribed circle diameter. The input data to the model include traffic data, site conditions, and limitations based on design guidelines. Application of the proposed model is illustrated using two actual roundabouts. The comparison results show that the proposed model provides substantial improvements in safety, mobility, and environmental sustainability compared with existing conditions. In addition, the model requires much less effort to apply compared with the traditional iterative method, and as such should be of interest to highway designers.

scholarly journals Multi-objective optimization of single-lane roundabout geometric design: safety, mobility, and environmental sustainability

2021 ◽  
Author(s):  
Hend Ahmed ◽  
Said M. Easa
Keyword(s):  
Environmental Sustainability ◽  
Vehicle Emissions ◽  
Geometric Design ◽  
Geometric Parameters ◽  
Specific Power ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Highway Safety Manual ◽  
Optimization Methodology ◽  
The Uk

Mobility, safety performance and environmental sustainability are priorities in the geometric design of roundabouts. This thesis presents a multi-objective optimization methodology for the geometric design of single-lane roundabouts. Mobility is defined in terms of roundabout delay and modeled using the (UK) empirical model. The collision frequency represents the safety objective, and modeled using the methodology outlined in the Highway Safety Manual. Environmental sustainability is represented by NOX, HC, CO2, and CO vehicle emissions and is modeled using the vehicle specific power (VSP) methodology. The presented model directly identifies the optimal geometric parameters of roundabouts. Traffic data, site conditions, and guidelines limitations were used as input data while the output decision values that minimize delay, collisions, and vehicle emissions are the optimal geometric parameters. The practical application of the proposed model is illustrated using an application example. The model was validated using an actual location, and a sensitivity analysis was conducted.

scholarly journals Multi-objective optimization of single-lane roundabout geometric design: safety, mobility, and environmental sustainability

2021 ◽  
Author(s):  
Hend Ahmed ◽  
Said M. Easa
Keyword(s):  
Environmental Sustainability ◽  
Vehicle Emissions ◽  
Geometric Design ◽  
Geometric Parameters ◽  
Specific Power ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Highway Safety Manual ◽  
Optimization Methodology ◽  
The Uk

Mobility, safety performance and environmental sustainability are priorities in the geometric design of roundabouts. This thesis presents a multi-objective optimization methodology for the geometric design of single-lane roundabouts. Mobility is defined in terms of roundabout delay and modeled using the (UK) empirical model. The collision frequency represents the safety objective, and modeled using the methodology outlined in the Highway Safety Manual. Environmental sustainability is represented by NOX, HC, CO2, and CO vehicle emissions and is modeled using the vehicle specific power (VSP) methodology. The presented model directly identifies the optimal geometric parameters of roundabouts. Traffic data, site conditions, and guidelines limitations were used as input data while the output decision values that minimize delay, collisions, and vehicle emissions are the optimal geometric parameters. The practical application of the proposed model is illustrated using an application example. The model was validated using an actual location, and a sensitivity analysis was conducted.

scholarly journals UTILITY-BASED MULTICRITERIA MODEL FOR EVALUATING BOT PROJECTS SEP PROJEKTŲ VERTINIMO MODELIS PAGRĮSTAS DAUGIAKRITERINE NAUDINGUMO TEORIJA / SEP PROJEKTŲ VERTINIMO MODELIS PAGRĮSTAS DAUGIAKRITERINE NAUDINGUMO TEORIJA

2011 ◽  
Vol 17 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Min-Ren Yan ◽  
Cheng-Sheng Pong ◽  
Wei Lo
Keyword(s):  
Evaluation Model ◽  
Objective Evaluation ◽  
Capital Investments ◽  
Analytic Hierarchy ◽  
Limited Government ◽  
Proposed Model ◽  
Multicriteria Model ◽  
Economic Developments ◽  
Hierarchy Process

Owing to the urgent demands for new developments and maintenances of the existing infrastructures under limited government budget and time, increasing BOT (build-operate-transfer) projects have been a significant factor affecting the economic developments in many countries. However, as BOT projects usually induce huge capital investments, government sectors must prudently evaluate the project feasibility from both financial and nonfinancial aspects before the implementation. Therefore, how to establish an objective evaluation model which can comprehensively assess the feasibility of each BOT project and determine the priority of its implementation has become an important issue. This study incorporates analytic hierarchy process (AHP) and utility theory to develop a utility-based multicriteria model for supporting the selection of BOT projects. A case study is provided to demonstrate that the implementation of the proposed model can effectively help decision-making teams participate in economical evaluations so that the feasibility of as-planed BOT projects can be determined and project priority can be set efficiently and consistently. Santrauka Dėl esamos infrastruktūros plėtros ir atnaujinimo būtinybės, esant ribotam valstybės biudžetui ir laikui, SEP (Statyba-Eksploatacija-Perdavimas) projektų vykdymas ženkliai prisidėjo prie daugelio šalių ekonominių pokyčių. Dažnai SEP projektai reikalauja didelių kapitalo investicijų, todėl valstybės sektorius turi įvertinti projekto įgyvendinimo galimybes tiek finansiniu tiek nefinansiu aspektu. Koks turi būti objektyvaus vertinimo modelis, kuris leistų visapusiškai įvertinti kiekvieno SEP projeto pagrįstumą ir nustatyti jo įgyvendinimo prioritetus? Šiame straipsnyje, naudojant analitinę hierarchinio proceso (AHP) struktūrą ir naudingumo teoriją, SEP projektų atrinkimui sukurtas daugiakriterine naudingumo teorija pagrįstas modelis. Skaitmeninis pavyzdys įrodo, kad siūlomas modelis gali sėkmingai pagelbėti atrenkant ekonomiškai efektyvius SEP projektus.

Construction of lean-green coordinated development model from the perspective of personnel integration in manufacturing companies

2020 ◽  
Vol 234 (11) ◽  
pp. 1460-1470
Author(s):  
Xiao-yong Zhu ◽  
Hua Zhang
Keyword(s):  
Environmental Sustainability ◽  
Objective Evaluation ◽  
Manufacturing Companies ◽  
Coordinated Development ◽  
Proposed Model ◽  
Network Process ◽  
Key Factor ◽  
Lean And Green ◽  
Primary Key ◽  
Organisation Management

Practising lean and green method has become important for organisations seeking competitiveness and environmental sustainability. The efficiency and validity of personnel (employees) in organisation management is an index to measure sustainability. Employees are the primary key factor in maintaining organisation management. In this study, a framework model was developed from the perspective of personnel integration, aiming to implement coordinated and sustainable management of lean-green enterprises. During the practice of lean-green in manufacturing companies, a model was constructed using an analytical network process and interpretation structural modelling. These models involve dynamic common indexes of cross-sector objective evaluation and artificial barriers in deep analysis. Horizontal and vertical personnel integrations were achieved based on this model. The proposed model is beneficial for deep personnel integration and lays a solid foundation for lean-green coordinated development.

Toolpath Patterns and Their Evaluation Methods in NC Machining

1996 ◽  
Author(s):  
Xinnong You ◽  
Youping Chen ◽  
Zude Zhou ◽  
Zhengcheng Duan
Keyword(s):  
Convex Polygon ◽  
Evaluation Model ◽  
Objective Evaluation ◽  
Evaluation Methods ◽  
Nc Machining ◽  
Sculptured Surfaces ◽  
Qualitative And Quantitative ◽  
Multi Objective

Abstract In this paper, various kinds of toolpath patterns are summarized and analyzed systematically for flat convex polygon, pocket with islands and sculptured surfaces. On this basis, the evaluation objectives of toolpath patterns are put forward, and a related fuzzy multi-objective evaluation model is presented to solve the problem of the assessment of alternatives with qualitative and quantitative criteria. At the end, an example of three toolpath patterns for the NC machining of a washer-wave-wheel is given to derive an optimal sorting sequence of them.

scholarly journals Geometric Design of Suburban Roundabouts

Encyclopedia ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 720-743
Author(s):  
Saša Ahac ◽  
Vesna Dragčević
Keyword(s):  
Comparative Analysis ◽  
Iterative Process ◽  
Design Guidelines ◽  
Geometric Design ◽  
Level Of Service ◽  
Vehicle Speed ◽  
Design Elements ◽  
Geometry Design ◽  
Central Island ◽  
Definition Of

A modern roundabout is an intersection with a circulatory roadway at which the vehicle speed is low, and the traffic is continuous and circulating in one direction around the central island towards the exits at the approach legs. Modern roundabout design is an iterative process that is composed of the following steps: (1) the identification of the roundabout as the optimal traffic solution; (2) the definition of the number of lanes at the intersection based on the required capacity and the level of service; (3) the initial design of the roundabout geometry; (4) design vehicle swept path, the fastest path analysis, and visibility performance checks; and (5) detailed roundabout design if the results of the performance checks are in line with the design recommendations. Initial roundabout geometry design elements are not independent of each other; therefore, care must be taken to provide compatibility between them. An overview and a comparative analysis of the initial geometric design elements for suburban single-lane roundabouts defined in roundabout design guidelines and norms used in Croatia, Austria, France, the Netherlands, Germany, Serbia, and Switzerland is given in this entry.

A FUZZY MULTI-OBJECTIVE EVALUATION MODEL IN SUPPLY CHAIN MANAGEMENT

2006 ◽  
Author(s):  
XIAOBEI LIANG ◽  
XINGHUA LIU ◽  
DAOLI ZHU ◽  
BINGYONG TANG ◽  
HONGWU ZHUANG
Keyword(s):  
Supply Chain ◽  
Supply Chain Management ◽  
Evaluation Model ◽  
Objective Evaluation ◽  
Chain Management ◽  
Multi Objective

scholarly journals Economical Speed for Optimizing the Travel Time and Energy Consumption in Train Scheduling using a Fuzzy Multi-Objective Model

2021 ◽  
Author(s):  
Ahmad Reza Jafarian-Moghaddam
Keyword(s):  
Energy Consumption ◽  
Travel Time ◽  
Pollutant Emissions ◽  
Scheduling Problems ◽  
Train Scheduling ◽  
Multi Objective ◽  
Consumption Ratio ◽  
Proposed Model ◽  
Objective Model ◽  
Time And Energy

AbstractSpeed is one of the most influential variables in both energy consumption and train scheduling problems. Increasing speed guarantees punctuality, thereby improving railroad capacity and railway stakeholders’ satisfaction and revenues. However, a rise in speed leads to more energy consumption, costs, and thus, more pollutant emissions. Therefore, determining an economic speed, which requires a trade-off between the user’s expectations and the capabilities of the railway system in providing tractive forces to overcome the running resistance due to rail route and moving conditions, is a critical challenge in railway studies. This paper proposes a new fuzzy multi-objective model, which, by integrating micro and macro levels and determining the economical speed for trains in block sections, can optimize train travel time and energy consumption. Implementing the proposed model in a real case with different scenarios for train scheduling reveals that this model can enhance the total travel time by 19% without changing the energy consumption ratio. The proposed model has little need for input from experts’ opinions to determine the rates and parameters.

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