69,340 research outputs found

    Hierarchical self-organization of non-cooperating individuals

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    Hierarchy is one of the most conspicuous features of numerous natural, technological and social systems. The underlying structures are typically complex and their most relevant organizational principle is the ordering of the ties among the units they are made of according to a network displaying hierarchical features. In spite of the abundant presence of hierarchy no quantitative theoretical interpretation of the origins of a multi-level, knowledge-based social network exists. Here we introduce an approach which is capable of reproducing the emergence of a multi-levelled network structure based on the plausible assumption that the individuals (representing the nodes of the network) can make the right estimate about the state of their changing environment to a varying degree. Our model accounts for a fundamental feature of knowledge-based organizations: the less capable individuals tend to follow those who are better at solving the problems they all face. We find that relatively simple rules lead to hierarchical self-organization and the specific structures we obtain possess the two, perhaps most important features of complex systems: a simultaneous presence of adaptability and stability. In addition, the performance (success score) of the emerging networks is significantly higher than the average expected score of the individuals without letting them copy the decisions of the others. The results of our calculations are in agreement with a related experiment and can be useful from the point of designing the optimal conditions for constructing a given complex social structure as well as understanding the hierarchical organization of such biological structures of major importance as the regulatory pathways or the dynamics of neural networks.Comment: Supplementary videos are to be found at http://hal.elte.hu/~nepusz/research/supplementary/hierarchy

    Smart Technologies for Environmental Safety and Knowledge Enhancement in Intermodal Transport

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    International concerns about security in transport systems are leading to a new international regulation in this field. This introduces new requirements for operators and authorities as well as it opens new challenges, in particular when referred to seaports and maritime transport in the Mediterranean area, where many seaport terminals and infrastructures are affected by a noteworthy technological divide from North European contexts. In such contexts, the adoption of the new regulations can represent the right chance for upgrading the local operative standards, increasing latu sensu the quality of maritime transport performances, while conferring a greater level to security and safety checks. This paper explores the chances for increasing the level of Mediterranean seaport competitiveness allowed by technological innovations in transport systems, both in operations and organization of these infrastructures. The aim of the work is to study the effects of the adoption of technological solutions such as wireless communications and radiofrequency identification on the competitiveness of Mediterranean seaport infrastructures. Technological solutions designed to identify good items help operators in organizing activities in terminals and make maritime transport faster in delivering goods, by cutting the handling time and costs in seaport terminals. Seaports that adopt this kind of technologies, and the surrounding economic areas connected to seaports, have a greater attractiveness on shipping companies and operators, since they allow faster handling activities and easier checks on goods. Besides, the analysis of direct and indirect effects of the use of such technologies specifically focuses on the contribution that the use of these solutions gives in ensuring higher security levels, by increasing the level of information and knowledge associated to goods. The different types of security provided (e.g. for people, environment and goods) and the extreme flexibility of the technologies involved give the overall worth of the challenge. It seems to be a great chance of growth for the Mediterranean area, more than a mere compliance to the international security regulations.

    CoRide: Joint Order Dispatching and Fleet Management for Multi-Scale Ride-Hailing Platforms

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    How to optimally dispatch orders to vehicles and how to tradeoff between immediate and future returns are fundamental questions for a typical ride-hailing platform. We model ride-hailing as a large-scale parallel ranking problem and study the joint decision-making task of order dispatching and fleet management in online ride-hailing platforms. This task brings unique challenges in the following four aspects. First, to facilitate a huge number of vehicles to act and learn efficiently and robustly, we treat each region cell as an agent and build a multi-agent reinforcement learning framework. Second, to coordinate the agents from different regions to achieve long-term benefits, we leverage the geographical hierarchy of the region grids to perform hierarchical reinforcement learning. Third, to deal with the heterogeneous and variant action space for joint order dispatching and fleet management, we design the action as the ranking weight vector to rank and select the specific order or the fleet management destination in a unified formulation. Fourth, to achieve the multi-scale ride-hailing platform, we conduct the decision-making process in a hierarchical way where a multi-head attention mechanism is utilized to incorporate the impacts of neighbor agents and capture the key agent in each scale. The whole novel framework is named as CoRide. Extensive experiments based on multiple cities real-world data as well as analytic synthetic data demonstrate that CoRide provides superior performance in terms of platform revenue and user experience in the task of city-wide hybrid order dispatching and fleet management over strong baselines.Comment: CIKM 201
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