scholarly journals The bi-objective multimodal car-sharing problem

OR Spectrum ◽  
2021 ◽  
Author(s):  
Miriam Enzi ◽  
Sophie N. Parragh ◽  
Jakob Puchinger
Keyword(s):  
User Satisfaction ◽  
Pareto Frontier ◽  
Planning Horizon ◽  
User Preferences ◽  
Point Of View ◽  
Branch And Cut ◽  
Travel Times ◽  
Car Sharing ◽  
Mode Of Transport ◽  
Constraint Method

AbstractThe aim of the bi-objective multimodal car-sharing problem (BiO-MMCP) is to determine the optimal mode of transport assignment for trips and to schedule the routes of available cars and users whilst minimizing cost and maximizing user satisfaction. We investigate the BiO-MMCP from a user-centred point of view. As user satisfaction is a crucial aspect in shared mobility systems, we consider user preferences in a second objective. Users may choose and rank their preferred modes of transport for different times of the day. In this way, we account for, e.g., different traffic conditions throughout the planning horizon. We study different variants of the problem. In the base problem, the sequence of tasks a user has to fulfil is fixed in advance and travel times as well as preferences are constant over the planning horizon. In variant 2, time-dependent travel times and preferences are introduced. In variant 3, we examine the challenges when allowing additional routing decisions. Variant 4 integrates variants 2 and 3. For this last variant, we develop a branch-and-cut algorithm which is embedded in two bi-objective frameworks, namely the $$\epsilon $$ ϵ -constraint method and a weighting binary search method. Computational experiments show that the branch-and cut algorithm outperforms the MIP formulation and we discuss changing solutions along the Pareto frontier.

Preferences for car sharing service attributes among university students: Evidence from an emerging market

2019 ◽  
Vol 24 (4) ◽  
pp. 636-653
Author(s):  
Nataša Bojković ◽  
Veljko Jeremić ◽  
Marijana Petrović ◽  
Slaven Tica
Keyword(s):  
University Students ◽  
Service Providers ◽  
Stated Preference ◽  
Emerging Market ◽  
Developed Countries ◽  
Sharing Economy ◽  
User Preferences ◽  
Point Of View ◽  
Car Sharing ◽  
Initiation Phase

Car sharing is a specific business model that allows a new form of personal mobility. University students, generally very receptive to the concept of a sharing economy, are recognized as a prospective customer group for car sharing operators. This paper proposes an ex ante analysis that aims to reveal how students from an area where car sharing is underdeveloped perceive this mobility option. University students in Belgrade were asked to state their preferences regarding a mix of attributes and levels replicating service design from current practice. Preferences for particular service attributes were explored using stated preference survey and Choice-Based Conjoint analysis, while further preference-based segmentation was obtained using the Partitioning Around Medoids method. The contribution of this work is that it delivers findings on an emerging car-sharing market where there is very little research on user profiles. From a methodological point of view, we form distinctive customer clusters based on the uniformity of their preferences. By being aware of users’ prior expectations, service providers can determine their operational priorities more easily when unlocking the market. The paper outlines both the similarities and differences between students in an emerging market and their counterparts in more developed countries. Our findings reveal that the student population is homogeneous regarding critical aspects of service adoption like cost, distance to vehicles, and parking convenience. Specific service attributes such as the pricing scheme and keeping vehicles clean are found to be issues of peculiar interest in our study market. Although our proposed approach to shaping user preferences was developed for car sharing analysis it is applicable to other service-oriented businesses in the initiation phase.

scholarly journals Assessing a Multi-Objective Genetic Algorithm with a Simulated Environment for Energy-Saving of Air Conditioning Systems with User Preferences

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 344
Author(s):  
Alejandro Humberto García Ruiz ◽  
Salvador Ibarra Martínez ◽  
José Antonio Castán Rocha ◽  
Jesús David Terán Villanueva ◽  
Julio Laria Menchaca ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Energy Consumption ◽  
Energy Saving ◽  
User Satisfaction ◽  
Air Conditioning ◽  
State Of The Art ◽  
User Preferences ◽  
The State ◽  
Nsga Ii ◽  
Air Conditioning System

Electricity is one of the most important resources for the growth and sustainability of the population. This paper assesses the energy consumption and user satisfaction of a simulated air conditioning system controlled with two different optimization algorithms. The algorithms are a genetic algorithm (GA), implemented from the state of the art, and a non-dominated sorting genetic algorithm II (NSGA II) proposed in this paper; these algorithms control an air conditioning system considering user preferences. It is worth noting that we made several modifications to the objective function’s definition to make it more robust. The energy-saving optimization is essential to reduce CO2 emissions and economic costs; on the other hand, it is desirable for the user to feel comfortable, yet it will entail a higher energy consumption. Thus, we integrate user preferences with energy-saving on a single weighted function and a Pareto bi-objective problem to increase user satisfaction and decrease electrical energy consumption. To assess the experimentation, we constructed a simulator by training a backpropagation neural network with real data from a laboratory’s air conditioning system. According to the results, we conclude that NSGA II provides better results than the state of the art (GA) regarding user preferences and energy-saving.

scholarly journals Low-Asymmetry Interface for Multiuser VR Experiences with Both HMD and Non-HMD Users

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 397
Author(s):  
Qimeng Zhang ◽  
Ji-Su Ban ◽  
Mingyu Kim ◽  
Hae Won Byun ◽  
Chang-Hun Kim
Keyword(s):  
Virtual Reality ◽  
Virtual Environment ◽  
Mobile Device ◽  
User Satisfaction ◽  
Virtual World ◽  
User Study ◽  
Visual Display ◽  
Point Of View ◽  
Head Mounted Display ◽  
And Behavior

We propose a low-asymmetry interface to improve the presence of non-head-mounted-display (non-HMD) users in shared virtual reality (VR) experiences with HMD users. The low-asymmetry interface ensures that the HMD and non-HMD users’ perception of the VR environment is almost similar. That is, the point-of-view asymmetry and behavior asymmetry between HMD and non-HMD users are reduced. Our system comprises a portable mobile device as a visual display to provide a changing PoV for the non-HMD user and a walking simulator as an in-place walking detection sensor to enable the same level of realistic and unrestricted physical-walking-based locomotion for all users. Because this allows non-HMD users to experience the same level of visualization and free movement as HMD users, both of them can engage as the main actors in movement scenarios. Our user study revealed that the low-asymmetry interface enables non-HMD users to feel a presence similar to that of the HMD users when performing equivalent locomotion tasks in a virtual environment. Furthermore, our system can enable one HMD user and multiple non-HMD users to participate together in a virtual world; moreover, our experiments show that the non-HMD user satisfaction increases with the number of non-HMD participants owing to increased presence and enjoyment.

scholarly journals New Housing Developments in the City Center of Guadalajara (Mexico): An Analysis from the Perspective of Collective and Sustainable Dwelling

Buildings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 168
Author(s):  
Alessandra Cireddu
Keyword(s):  
Point Of View ◽  
City Center ◽  
Compact City ◽  
Housing Developments ◽  
Human Scale ◽  
Horizontal Growth ◽  
Downtown Redevelopment ◽  
Mode Of Transport ◽  
The City ◽  
New Buildings

New vertical housing developments in Guadalajara (Mexico) are reaching the city center as a response for redensification after many years of expansion of the urban area characterized by a suburban, low density and fragmented pattern. This horizontal growth, dominated by use of the automobile as prevailing mode of transport, has proven to be unsustainable not only from an environmental point of view, but also from a social perspective where the “human scale” of the city has been affected, same as the daily life of its inhabitants. On the other hand, vertical housing proposals are by their very nature associated with concepts of redensification, compact city and collective living; the aim of this article is to analyze some new housing developments in Guadalajara downtown in order to evaluate to what extent the new buildings embody a more sustainable, livable and collective dwelling, to discuss findings, successes and failures and thus be able to contribute some conclusions and open a broader reflection about contemporary housing, urban density and downtown redevelopment in Latin America cities through collective and sustainable dwelling.

scholarly journals Landscape Design of University Campuses and User Satisfaction

2021 ◽  
Author(s):  
Deniz Gozde Ertin Tezgor ◽  
◽  
Beste Karakaya Aytin ◽  
Keyword(s):  
Public Space ◽  
User Satisfaction ◽  
Point Of View ◽  
Green Spaces ◽  
Survey Study ◽  
User Needs ◽  
University Campus ◽  
Art And Design ◽  
University Campuses ◽  
User Space

University campus gardens provide the integrity of the environment with educational buildings, connect the users and buildings, and provide liveable spaces for users. Campuses serve as a public space for academic, administrative and technical staff, especially students, as well as incoming visitors. As a public space, the ability of students to meet all their recreational, social and cultural needs is directly related to the content and designs of the open and green spaces of the campuses. It is essential to ensure the landscape designs of these spaces, in line with the structural and planting design principles, and with the successful composition of the user-space relationship where the user needs and desires are determined. From this point of view, it is aimed to evaluate the landscape designs of the two campuses of Trakya University, where art and design-oriented education is realised, in terms of user satisfaction. For this purpose, it was revealed by a survey that measures the satisfaction of the users of the two campuses where determined the spatial and landscape requirements of design-based education. In the survey, the users' duration and purpose of use of the campus, feelings created by various equipment on users, the usage the building and gardens and the current conditions of the campuses were determined. The frequency percentages of the data obtained in the survey study were evaluated using the SPSS 26.0 program. As a result, suggestions have been developed to improve the current use of the two campus gardens and to ensure the sustainability of the spaces.

scholarly journals Developing a Dashboard Software for the ICUs and Studying its Impact on Reducing the Ventilator-Associated Pneumonia

2018 ◽  
Vol 12 (1) ◽  
pp. 42-50
Author(s):  
Mohammad Fathi ◽  
Hamid Moghaddasi ◽  
Azamossadat Hosseini ◽  
Monir Ebrahimi Aghdam
Keyword(s):  
User Satisfaction ◽  
Pilot Project ◽  
Point Of View ◽  
P Value ◽  
Ventilator Associated Pneumonia ◽  
Healthcare Organizations ◽  
Survey Tool ◽  
Usability Assessment ◽  
Before And After ◽  
The Impact

Objective: Ventilator-Associated Pneumonia (VAP), a lung infection developing in patients on a ventilator in Intensive Care Units (ICU), is the second most common nosocomial infection and a leading cause of morbidity and mortality in ICUs. To reduce the incidence rate of VAP complication, many healthcare organizations have already developed certain strategies and guidelines. However, there are still high rates of VAP infections mainly due to: conflicting guidelines from different sources, implementing the guidelines at different times and conditions, different ICU caregivers at different shifts, and of course the human mistakes. Methods: The present study aimed to develop a dashboard to help reducing VAP incidences in ICUs. To achieve the objective of the research, first, the VAP prevention guidelines were compiled. The object-oriented analysis approach was adopted for designing of the dashboard software. To assess the impact of the developed dashboard on the reduction of VAP events, a pilot hospital was selected and a pilot project was prepared. For the dashboard usability assessment based on user satisfaction, a questionnaire was developed as the survey tool. Conclusion: The dashboard was developed and put into operation in a pilot ICU. The results from the t-test (with a probable error of 0.05 percent) indicated a meaningful difference between the number of VAP patients before and after the dashboard implementation with p-value ˂ 0.02. Also, the developed software was evaluated from a usability point of view based on user satisfaction, with health professionals and caregivers of the pilot ICU as the users of the software. The total score was equivalent to 95 percent, falling within the acceptable range of 75-100 percent.

Robust Data-Driven Vehicle Routing with Time Windows

2021 ◽  
Author(s):  
Yu Zhang ◽  
Zhenzhen Zhang ◽  
Andrew Lim ◽  
Melvyn Sim
Keyword(s):  
Time Windows ◽  
Risk Index ◽  
Decision Criterion ◽  
Wasserstein Distance ◽  
Branch And Cut ◽  
Travel Times ◽  
Robust Solution ◽  
Deterministic Routing ◽  
Service Fulfillment ◽  
Timely Delivery

On-time delivery is of utmost importance in today’s urban logistics. However, travel times are uncertain and classical deterministic routing solutions often fail to ensure timely delivery. In this paper, a robust solution that exploits travel times data to determine the best routes for maximal timely delivery is proposed. A new decision criterion is introduced, the service fulfillment risk index (sri), which accounts for both the late arrival probability and its magnitude. Together with Wasserstein distance–based ambiguity in travel times, sri can be evaluated efficiently in closed form. In addition, an exact branch-and-cut approach and a meta-heuristic algorithm are developed to minimize sri with a given travel cost. Simulation studies demonstrate that handling uncertainty improves service punctuality, and that incorporating ambiguity prevents overfitting. Most importantly, sri outperforms the canonical decision criteria of lateness probability and expected lateness duration.

OPNET Simulation Setup for QoE Based Network Selection

2012 ◽  
pp. 100-139
Author(s):  
Umar Toseef ◽  
Manzoor Ahmed Khan
Keyword(s):  
User Satisfaction ◽  
Discrete Event ◽  
Mobile Terminal ◽  
Research Literature ◽  
User Preferences ◽  
Transport Infrastructure ◽  
Network Simulator ◽  
Component Development ◽  
Efficient Resource

In its most generic sense, the user-centric view in telecommunications considers that the users are free from subscription to any one network operator and can instead dynamically choose the most suitable transport infrastructure from the available network providers for their terminal and application requirements. In this approach, the decision of interface selection is delegated to the mobile terminal enabling end users to exploit the best available characteristics of different network technologies and network providers, with the objective of increased satisfaction. In order to more accurately express the user satisfaction in telecommunications, a more subjective and application-specific measure, namely, the Quality-of-Experience (QoE) is introduced. QoE is the core requirement in future wireless networks and provisions. It is a framework that optimizes the global system of networks and users in terms of efficient resource utilization and meeting user preferences (guaranteeing certain Quality-of-Service [QoS] requirements). A number of solution frameworks to address the mentioned problems using different theoretical approaches are proposed in the research literature. Such scholarly approaches need to be evaluated using simulation platforms (e.g., OPNET, NS2, OMNET++, etc.). This chapter focuses on developing the simulation using a standard discrete event network simulator, OPNET. It outlines the general development procedures of different components in simulation and details the following important aspects: Long Term Evolution (LTE) network component development, impairment entity development, implementing IPv6 flow management, developing an integrated heterogeneous scenario with LTE and WLAN, implementing an example scenario, and generating and analyzing the results.

Music Retrieval and Recommendation Scheme Based on Varying Mood Sequences

2012 ◽  
pp. 257-273 ◽  
Author(s):  
Sanghoon Jun ◽  
Seungmin Rho ◽  
Eenjun Hwang
Keyword(s):  
User Satisfaction ◽  
Clustering Algorithm ◽  
Sequence Similarity ◽  
User Interaction ◽  
User Preferences ◽  
New Music ◽  
Music Recommendation ◽  
Unsatisfactory Result ◽  
Music Retrieval ◽  
Music Clip

A typical music clip consists of one or more segments with different moods and such mood information could be a crucial clue for determining the similarity between music clips. One representative mood has been selected for music clip for retrieval, recommendation or classification purposes, which often gives unsatisfactory result. In this paper, the authors propose a new music retrieval and recommendation scheme based on the mood sequence of music clips. The authors first divide each music clip into segments through beat structure analysis, then, apply the k-medoids clustering algorithm for grouping all the segments into clusters with similar features. By assigning a unique mood symbol for each cluster, one can transform each music clip into a musical mood sequence. For music retrieval, the authors use the Smith-Waterman (SW) algorithm to measure the similarity between mood sequences. However, for music recommendation, user preferences are retrieved from a recent music playlist or user interaction through the interface, which generates a music recommendation list based on the mood sequence similarity. The authors demonstrate that the proposed scheme achieves excellent performance in terms of retrieval accuracy and user satisfaction in music recommendation.

A Survey on Recent Recommendation Systems for the Tourism Industry

2020 ◽  
pp. 205-237
Author(s):  
S. Ranjith ◽  
P. Victer Paul
Keyword(s):  
User Satisfaction ◽  
Recommendation System ◽  
Recommendation Systems ◽  
Tourism Industry ◽  
User Preferences ◽  
Reference List ◽  
Current State ◽  
Recent Recommendation ◽  
Important Field ◽  
Preference Criteria

Data mining is an important field that derives insights from the data and recommendation systems. Recommendation systems have become common in recent years in the field of tourism. These are widely used as a tool that can input various selection criteria and user preferences and yields travel recommendations to tourists. User's style and preferences should be constructed accurately so as to supply most relevant suggestions. Researchers proposed various types of tourism recommendation systems (TRS) in order to improve the accuracy and user satisfaction. In this chapter, the authors studied the current state of tourism recommendation system models and discussed their preference criteria. As a part of that, the authors studied various important preference factors in TRS and categorized them based on their likeness. This chapter reports TRS model future directions and compiles a comprehensive reference list to assist researchers.

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