Estimating Self-Sustainability in Peer-to-Peer Swarming Systems

Peer-to-peer swarming is one of the \emph{de facto} solutions for distributed content dissemination in today's Internet. By leveraging resources provided by clients, swarming systems reduce the load on and costs to publishers. However, there is a limit to how much cost savings can be gained from swarming; for example, for unpopular content peers will always depend on the publisher in order to complete their downloads. In this paper, we investigate this dependence. For this purpose, we propose a new metric, namely \emph{swarm self-sustainability}. A swarm is referred to as self-sustaining if all its blocks are collectively held by peers; the self-sustainability of a swarm is the fraction of time in which the swarm is self-sustaining. We pose the following question: how does the self-sustainability of a swarm vary as a function of content popularity, the service capacity of the users, and the size of the file? We present a model to answer the posed question. We then propose efficient solution methods to compute self-sustainability. The accuracy of our estimates is validated against simulation. Finally, we also provide closed-form expressions for the fraction of time that a given number of blocks is collectively held by peers.Comment: 27 pages, 5 figure

Self-Sustaining Iterated Learning

An important result from psycholinguistics (Griffiths & Kalish, 2005) states that no language can be learned iteratively by rational agents in a self-sustaining manner. We show how to modify the learning process slightly in order to achieve self-sustainability. Our work is in two parts. First, we characterize iterated learnability in geometric terms and show how a slight, steady increase in the lengths of the training sessions ensures self-sustainability for any discrete language class. In the second part, we tackle the nondiscrete case and investigate self-sustainability for iterated linear regression. We discuss the implications of our findings to issues of non-equilibrium dynamics in natural algorithms

Towards an Agent Based Framework for Modelling Smart Self-Sustainable Systems

Self-sustainability is a property of a system; a system is considered to be self-sustainable if it can sustain itself without external support in an observed period of time. If this property is mapped to a human settlement in context of resources (water, energy, food, etc.), it would describe a human settlement which is independent of external resources (like the national electrical grid or a central water distribution system), where such external resources are either not available, or not desirable. This article contributes to presenting the state-of-the-art overview of self-sustainability-related research. While self-sustainability as in the above described form was not a direct subject of research, there are several fields which are either related to, or could be of significant value to the self-sustainability research in this context. The extensive literature overview also showed no frameworks for modeling self sustainable systems in the context of human settlements. Herein a motivation for using agent-based modeling and simulation techniques will be given

Holonic self-sustainable systems for electrical micro grids

The self-sustainability of micro grids is an important challenge in the smart grids field due to the need to balance the fast growing energy consumption, reduce greenhouse gas emissions and increase energy independence by using renewable resources. The use of decentralized paradigms, and particularly multi-agent systems and holonic control, enable to face this challenge by implementing intelligent mechanisms that allow an efficient management of the power flow. In this paper, a holonic based model is introduced, considering load scheduling and forecast mechanisms to improve the micro grids self-sustainability, and consequently reduce the energy cost and the energy dependency from the main utility. The designed holonic based model and strategies were developed by using the agent technology, and particularly the JADE framework, showing important improvements in the self-sustainability of micro grids working in different operating modes.info:eu-repo/semantics/publishedVersio

Refugee Communities: a campaign for Self-Sustainability

The struggles of becoming self-sustainable and gaining independence from resettling institutions are prominent ones for refugees who resettled to a host country. A multitude of obstacles such as language barriers, cultural differences, and loss of sense of purpose in life are phenomena often experienced by refugees regardless of ethnicity and nationality. These phenomena leave struggling refugees in a state of dependence on any form of guidance and support in order to achieve full assimilation. Through my work at the International Institute of Rhode Island in the refugee resettlement office, I witnessed the crucial role that this humanitarian organization plays in the resettlement system. Providing paperwork and documents, housing and initial capital is something that only an institution could afford to do equally for all of its clients. The International Institute of Rhode Island, although acting in western style, provides initial help to the refugees necessary for any kind of stabilization in a developed country such as the United States. Simultaneously to witnessing the irreproducible help offered by IIRI, I have also witnessed the effects of a system that unintentionally promotes dependence rather than independence. Providence Rhode Island, for example, is a city in which it’ refugees suffer from the resettlement system because of a lack of refugee communities to which to turn to for mutual help. These refugee communities, through alleviation of culture shock, helping with lingual barriers and promotion of cultural traditions, limit the dependence on a western institution because of the sense of self-sustainability that they promote. Because of its abundance of Burundi refugees, Providence is a city that is in dire need for a Burundi community. Interviews with Somali and Burundi refugee where taken to conclude whether a refugee community was something sought after by refugees in Providence and whether it was possible to create. My hypothesis states that because of cultural similarities between the two ethnic groups, just as Somali refugees have been successful in building refugee communities around the country, Burundi refugees also have the desire and capabilities to create a Burundi community in Providence. My hypothesis is proven correct after analyzing the answers collected from the interviews taken with refugees of both ethnic groups. A Burundi community is something that is wanted and needed in Providence and through minimal support from humanitarian institutions such as the International Institute of Rhode Island in encouraging the communication between Burundi refugees, this desire can become a reality

Fuel cells for power generation and organic waste treatment on the island of Mull

In-situ use of biomass and organic waste streams have the potential to provide the key to energy self sustainability for islands and remote communities. Traditionally biogas fuels have been used in combustion engines for electric power generation. However, fuel cells offer the prospect of achieving higher generating efficiencies, and additionally, important environmental benefits can be achieved by way of mitigating greenhouse gas emissions, whilst providing a carbon sink. This paper presents the design details of a biogas gas plant and fuel cell installation that will provide a practical solution on an island (and be applicable in other remote and rural areas) where connection to the grid can be expensive, and where biofuels can be produced on site at no significant extra cost