Collective Fast Delivery by Energy-Efficient Agents

We consider k mobile agents initially located at distinct nodes of an undirected graph (on n nodes, with edge lengths). The agents have to deliver a single item from a given source node s to a given target node t. The agents can move along the edges of the graph, starting at time 0, with respect to the following: Each agent i has a weight omega_i that defines the rate of energy consumption while travelling a distance in the graph, and a velocity upsilon_i with which it can move. We are interested in schedules (operating the k agents) that result in a small delivery time T (time when the item arrives at t), and small total energy consumption E. Concretely, we ask for a schedule that: either (i) Minimizes T, (ii) Minimizes lexicographically (T,E) (prioritizing fast delivery), or (iii) Minimizes epsilon * T + (1-epsilon)* E, for a given epsilon in (0,1). We show that (i) is solvable in polynomial time, and show that (ii) is polynomial-time solvable for uniform velocities and solvable in time O(n+k log k) for arbitrary velocities on paths, but in general is NP-hard even on planar graphs. As a corollary of our hardness result, (iii) is NP-hard, too. We show that there is a 2-approximation algorithm for (iii) using a single agent

Collective fast delivery by energy-efficient agents

We consider k mobile agents initially located at distinct nodes of an undirected graph (on n nodes, with edge lengths) that have to deliver a single item from a given source node s to a given target node t. The agents can move along the edges of the graph, starting at time 0 with respect to the following: Each agent i has a weight w_i that defines the rate of energy consumption while travelling a distance in the graph, and a velocity v_i with which it can move. We are interested in schedules (operating the k agents) that result in a small delivery time T (time when the package arrives at t), and small total energy consumption E. Concretely, we ask for a schedule that: either (i) Minimizes T, (ii) Minimizes lexicographically (T,E) (prioritizing fast delivery), or (iii) Minimizes epsilon*T + (1-epsilon)*E, for a given epsilon, 0<epsilon<1. We show that (i) is solvable in polynomial time, and show that (ii) is polynomial-time solvable for uniform velocities and solvable in time O(n + k log k) for arbitrary velocities on paths, but in general is NP-hard even on planar graphs. As a corollary of our hardness result, (iii) is NP-hard, too. We show that there is a 3-approximation algorithm for (iii) using a single agent.Comment: In an extended abstract of this paper [MFCS 2018], we erroneously claimed the single agent approach for variant (iii) to have approximation ratio

Building and interconnecting hydrogen networks : insights from the electricity and gas experience in Europe

This paper aims to investigate the transition to a new energy system based on hydrogen in the European liberalized framework. After analyzing the literature on the hydrogen infrastructure needs in Europe, we estimate the size and scope of the transition challenge. We take the theoretical framework of network economics to analyze early hydrogen infrastructure needs. Therefore, several concepts are applied to hydrogen economics such as demand club effects, scale economies on large infrastructures, scope economies, and positive socio-economical externalities. On the examples of the electricity and natural gas industry formation in Europe, we argue for public intervention in order to create conditions to reach more rapidly the critical size of the network and to prompt network externalities allowing for the market diffusion of and, thus, an effective transition to the new energy system.Network economics ; infrastructure ; hydrogen

An Unbiased Pareto Improvement strategy for poverty alleviation

There are historical and institutional reasons behind our economic problems like poverty and environmental damage but it is not acceptable if they persist in years to come. The strategic use of information by individual economic agents establishes a biasing effect on our economy. In case of poverty, economic efforts of poor people are continuously undervalued and therefore, true welfare across an economy cannot be achieved without protecting the poor people for their immediate economic needs and simultaneously counteracting the biasing forces. This article describes an Unbiased Pareto Improvement (UPI) strategy to be implemented across an economy and eventually across the world to solve poverty problems. This strategy describes making business opportunities involving poor people as well as helping government to set up pro-poor economic policies and infrastructures. A new indicator RICR (Real Income to Contribution Ratio) is introduced to measure its performance.Bangladesh, Economics of information, micro credit, micro finance, Pareto improvement, poverty, social business, real income, Yunus

Collaborative Delivery with Energy-Constrained Mobile Robots

We consider the problem of collectively delivering some message from a specified source to a designated target location in a graph, using multiple mobile agents. Each agent has a limited energy which constrains the distance it can move. Hence multiple agents need to collaborate to move the message, each agent handing over the message to the next agent to carry it forward. Given the positions of the agents in the graph and their respective budgets, the problem of finding a feasible movement schedule for the agents can be challenging. We consider two variants of the problem: in non-returning delivery, the agents can stop anywhere; whereas in returning delivery, each agent needs to return to its starting location, a variant which has not been studied before. We first provide a polynomial-time algorithm for returning delivery on trees, which is in contrast to the known (weak) NP-hardness of the non-returning version. In addition, we give resource-augmented algorithms for returning delivery in general graphs. Finally, we give tight lower bounds on the required resource augmentation for both variants of the problem. In this sense, our results close the gap left by previous research.Comment: 19 pages. An extended abstract of this paper was published at the 23rd International Colloquium on Structural Information and Communication Complexity 2016, SIROCCO'1

Mechanisms of Governance of Sustainable Development

In this paper we incorporate the interdisciplinary New Institutional and Transaction Costs Economics (combining Economics, Organization, Law, Sociology, Behavioral and Political Sciences), and suggest a framework for analyzing the mechanisms of governance of sustainable development. The agricultural sector is used to illustrate the approach, test the framework, and support with examples. Firstly, we discuss the modern concepts and the economics of sustainability. Secondly, we present a new framework for analysis and improvement of the governance of sustainable development. This new approach takes into account the role of specific institutional environment; and the behavioral characteristics of individual agents; and the transaction costs associated with the various forms of governance; and the critical factors of economic activity and exchanges; and the comparative efficiency of market, private, public and hybrid modes; and the potential of production structures for adaptation; and the comparative efficiency of alternative modes for public intervention. Finally, we identify specific modes for environmental governance in Bulgarian agriculture; and access the efficiency of market, private and public modes; and estimate the prospects for evolution of environmental governance in the conditions of EU CAP implementation. Agrarian development is associated with specific (different from other European states) environmental challenges such as degradation and contamination of farmland, pollution of surface and ground waters, loss of biodiversity, significant greenhouse gas emissions etc. That is a result of the specific institutional and governing structure evolving in the sector during the past 20 years. Implementation of the common EU policies will have unlike results in “Bulgarian” conditions enlarging income, technological, social and environmental discrepancy between different farms, sub-sectors and regions. Dominating subsistence farming, production cooperatives, small-scale commercial farms, and large business firms will be highly sustainable in years to come.mechanisms of governance; sustainable development; institutions, market, private, public and hybrid modes of governance; transaction costs; agrarian sustainability; environmental governance; Bulgaria