Analyzing Peer Selection Policies for BitTorrent Multimedia On-Demand Streaming Systems in Internet

The adaptation of the BitTorrent protocol to multimedia on-demand streaming systems essentially lies on the modification of its two core algorithms, namely the piece and the peer selection policies, respectively. Much more attention has though been given to the piece selection policy. Within this context, this article proposes three novel peer selection policies for the design of BitTorrent-like protocols targeted at that type of systems: Select Balanced Neighbour Policy (SBNP), Select Regular Neighbour Policy (SRNP), and Select Optimistic Neighbour Policy (SONP). These proposals are validated through a competitive analysis based on simulations which encompass a variety of multimedia scenarios, defined in function of important characterization parameters such as content type, content size, and client interactivity profile. Service time, number of clients served and efficiency retrieving coefficient are the performance metrics assessed in the analysis. The final results mainly show that the novel proposals constitute scalable solutions that may be considered for real project designs. Lastly, future work is included in the conclusion of this paper.Comment: 19 PAGE

Unburnable Carbon 2013: Wasted Capital and Stranded Assets

This report examines CO2 budgets and the growing 'carbon bubble', as well as its effects on the economy and global warming. It includes chapters on the global CO2 budget, global listed coal oil and gas reserves and resources, evolving the regulation of markets for climate risk, implications for equity valuation and credit ratings, implications for investors, and suggestions for navigating the road ahead

Practical applications of performance modelling of security protocols using PEPA

PhD ThesisTrade-off between security and performance has become an intriguing area in recent years in both the security and performance communities. As the security aspects of security protocol research is fully- edged, this thesis is therefore devoted to conducting a performance study of these protocols. The long term objective is to translate formal de nitions of security protocols to formal performance models automatically, then analysing by relevant techniques. In this thesis, we take a preliminary step by studying five typical security protocols, and exploring the methodology of construction and analysis of their models by using the Markovian process algebra PEPA. Through these case studies, an initial framework of performance analysis of security protocol is established. Firstly, a key distribution centre is investigated. The basic model su ers from the commonly encountered state space explosion problem, and so we apply some efficient solution techniques, which include model reduction techniques and ordinary di fferential equation based fluid flow analysis. Finally, we evaluate a utility function for this secure key exchange model. Then, we explore two non-repudiation protocols. Mean value analysis has been applied here for a class of PEPA models, and it is compared with an ODE approximation. After that, an optimistic nonrepudiation protocol with off-line third trust party is studied. The PEPA model has been formulated using a concept of multi-threaded servers with functional rates. The nal case study is a cross-realm Kerberos protocol. A simplified technique of aggregation with an ODE approximation is performed to do efficient cient analysis. All these modelling and analysis methods are illustrated through numerical examples

Survey Expectations

This paper focuses on survey expectations and discusses their uses for testing and modeling of expectations.Alternative models of expectations formation are reviewed and the importance of allowing for heterogeneity of expectations is emphasized. A weak form of the rational expectations hypothesis which focuses on average expectationsrather than individual expectations is advanced. Other models of expectations formation, such as the adaptive expectations hypothesis, are briefly discussed. Testable implications of rational and extrapolative models of expectationsare reviewed and the importance of the loss function for the interpretation of the test results is discussed. The paper thenprovides an account of the various surveys of expectations, reviews alternative methods of quantifying the qualitative surveys, and discusses the use of aggregate and individual survey responses in the analysis of expectations and for forecasting

Audit and External Informational System

The article describes in a real and elaborate manner the aspects concerning the correlation between statutory audit and the financial communication provided by the entity, by means of financial statements. In order to avail of a complex image of this issue, we have begun by stating clearly the importance confered on the financial communication supplied by the entity, particulalrly, when dealing with companies quoted on Stock Exchange,which enables us to observe the reason why certain objectives concerning the external communication should be covered by IFRS together with accounting standards.Simultaneously, the audit standard, as part of operational mechanisms necessary for the economy and the success of capital markets, has been reconsidered to improve the financial communication of the entity with the environment in which it operates. Therefore, we may consider the audit as a means of developing a high-achieving communication, concerned with the users outside the entity and required for the management performance.audit, financial communication, financial statements, decisions, transparency.

The Common Agricultural Policy and EU Enlargement: Implications for Agricultural Production in the Central and Eastern European Countries

This paper focuses on the consequences that an extension of the Common Agricultural Policy could have on agricultural production in the Central and Eastern European Countries. It reviews the evidence presented by recent attempts to quantify the potential impacts of accession on production levels in the CEECs. It also takes into account results from previous studies in order to analyse the importance that structural constraints might have on the capacity of the CEECs' agricultural sectors to respond to supply incentives under accession to the EU, and to examine some research questions that are still unanswered in relation to the supply potential of the CEECs. Some conclusions and policy recommendations are drawn at the end.CAP, CEECs, EU enlargement, supply response, structural constraints., Agricultural and Food Policy,

Spot price modelling of industrial metals – an heterogeneous agent based model for Copper

Abstract We will show in this paper the role of inventories in explaining copper price volatility. Using a three factor model we derive a fundamental long-term value for copper. Second, we emphasis the significance of this fundamental long-term value by considering an agent based model approach in which mean-reversion focused fundamental investors trade with chartists who follow price trends. We show that fundamental investors take increasing positions in copper when the spot price of copper deviated from its fundamental value (i.e. the fundamental value is higher than the spot price) and chartists loose relative significance

Two optimistic traditions in the dismal science: rationalism and the "invisible hand"

This paper explores two traditions of optimism in economics. In one of these traditions optimism is based on the comprehension of a spontaneous (and often progressive) order in a decentralised (or market) economy – what I will call the optimism of the “invisible hand”. Against the optimism of the invisible hand stands another optimistic tradition in economics, whereby we might take courage from our ability to do right by society through instructing governments with the keen edge of our most enlightened plans. This tradition is called “constructivist rationalism” here. The paper explores the logic of each tradition and their historical development and applies both to a recent example of policy making in South Africa: government’s fundamental regulatory overhaul of the pharmaceutical industry based on the Medicines Act of 1997, specifically, the decision to implement price controls on medicines.Spontaneous order, Modernism, Planning, Optimism, Information, Uncertainty, Price controls, Institutions, Constitutions, Law and Economics