Contributions on agreement in dynamic distributed systems

139 p.This Ph.D. thesis studies the agreement problem in dynamic distributed systems by integrating both the classical fault-tolerance perspective and the more recent formalism based on evolving graphs. First, we developed a common framework that allows to analyze and compare models of dynamic distributed systems for eventual leader election. The framework extends a previous proposal by Baldoni et al. by including new dimensions and levels of dynamicity. Also, we extend the Time-Varying Graph (TVG) formalism by introducing the necessary timeliness assumptions and the minimal conditions to solve agreement problems. We provide a hierarchy of time-bounded, TVG-based, connectivity classes with increasingly stronger assumptions and specify an implementation of Terminating Reliable Broadcast for each class. Then we define an Omega failure detector, W, for the eventual leader election in dynamic distributed systems, together with a system model, , which is compatible with the timebounded TVG classes. We implement an algorithm that satisfy the properties of W in M. According to our common framework, M results to be weaker than the previous proposed dynamic distributed system models for eventual leader election. Additionally we use simulations to illustrate this fact and show that our leader election algorithm tolerates more general (i.e., dynamic) behaviors, and hence it is of application in a wider range of practical scenarios at the cost of a moderate overhead on stabilization times

Regulatory framework of strike and its problem in Latvia

International legal provisions provide for human rights and freedoms, and the freedom of expression and the right to work belong to these. Considering that during any employment relationship disputes can arise between the involved parties, international legal provisions state that a strike as the final means for the settlement of a dispute can be used. Paragraph 108 of the Satversme (the Constitution of Latvia) provides that in Latvia, employed people have the right to strike. Systematically, the provisions of the Constitution are being regulated by the Labour Dispute Law and the Strike Law. It might seem that in Latvia, any employed person has been entitled to the right to strike as provided by the Satversme. However, the strike of general practitioners in summer 2017 highlighted the problem of executing strikes. Firstly, at the time being, the right to strike can only be associated with one form of employment, i.e., employment relationship. As only a part of general practitioners is employed on the basis of an employment agreement, the strike regulatory framework that is in force in Latvia can be used only by a part of general practitioners employed under an employment agreement in order to protect their collective interests. Secondly, the Labour Dispute Law provides for that a strike as the final means can be used exclusively for the protection of collective interests (within the framework of concluding a collective agreement), but not within the framework of a contract governed by public law. The strike by general practitioners showed that Latvia has complied only partially with international legal provisions because a strike can only be used by people employed under employment agreements and only in disagreements regarding a Collective agreement. In order to resolve this problem so that any employed person is entitled to the right to strike in the future, it is necessary to amend the Labour Dispute Law by expanding the range of labour dispute subjects. The aim: to analyse international and Latvia's regulatory framework for the right of employed people to strike and recommend necessary amendments to laws to solve detected problems. Materials used: international legal provisions and Latvian legal acts, publications and literature. Methods used in this article: descriptive, analysis, synthesis, dogmatic, induction and deduction as well as legal interpretation methods – grammatical, systemic, historical and teleological.publishersversionPeer reviewe

Does the diffusion DM-DE interaction model solve cosmological puzzles?

We study dynamics of cosmological models with diffusion effects modeling dark matter and dark energy interactions. We show the simple model with diffusion between the cosmological constant sector and dark matter, where the canonical scaling law of dark matter $(\rho_{dm,0}a^{-3}(t))$ is modified by an additive $\epsilon(t)=\gamma t a^{-3}(t)$ to the form $\rho_{dm}=\rho_{dm,0}a^{-3}(t)+\epsilon(t)$. We reduced this model to the autonomous dynamical system and investigate it using dynamical system methods. This system possesses a two-dimensional invariant submanifold on which the DM-DE interaction can be analyzed on the phase plane. The state variables are density parameter for matter (dark and visible) and parameter $\delta$ characterizing the rate of growth of energy transfer between the dark sectors. A corresponding dynamical system belongs to a general class of jungle type of cosmologies represented by coupled cosmological models in a Lotka-Volterra framework. We demonstrate that the de Sitter solution is a global attractor for all trajectories in the phase space and there are two repellers: the Einstein-de Sitter universe and the de Sitter universe state dominating by the diffusion effects. We distinguish in the phase space trajectories, which become in good agreement with the data. They should intersect a rectangle with sides of $\Omega_{m,0}\in [0.2724, 0.3624]$, $\delta \in [0.0000, 0.0364]$ at the 95\% CL. Our model could solve some of the puzzles of the $\Lambda$CDM model, such as the coincidence and fine-tuning problems. In the context of the coincidence problem, our model can explain the present ratio of $\rho_{m}$ to $\rho_{de}$, which is equal $0.4576^{+0.1109}_{-0.0831}$ at a 2$\sigma$ confidence level.Comment: 27 pages, 17 figure

THE FUTURE OF GATS ARTICLE XV: SERVICE SUBSIDY REGULATIONS UNDER THE WTO

The General Agreement on Trades in Services (GATS) is a multilateral framework of principles and rules for trade in services under the World Trade Organization (WTO). This dissertation aims to provide regulatory structure for Article XV of the GATS. GATS Article XV targets subsidies in service trades, but does not stipulate any detailed rules. Currently, GATS Article XV only contains guidelines for Members in future negotiations. Little progress has been made in those negotiations. I propose a service subsidy definition based on the Agreement on Subsidies and Countervailing Measures (SCMA), with some adjustments to adapt rules applicable to trade in goods to service trades. With respect to the subsidy categorization system, I propose a hybrid mechanism for Members to consider. Traffic-light categorization under the SCMA and the Amber/Blue/Green Box System under the Agreement on Agriculture (AoA) are two existing categorization systems under the WTO. The hybrid system of categorization I propose aims to associate the advantages of the two existing systems for trade in goods, taking into account the four modes by which services are supplied across borders. In the end, I do not propose to solve all of the problems in determining the appropriateness of countervailing duty procedures. The lack of available data is a key obstacle. However, I do propose several collection procedures based on the VAT/RST tax systems. The problem of collecting countervailing duties on service subsidies is not without a solution. I will identify the problems and suggest some models for a workable solution. My research also indicates that WTO Members will need to give service subsidies greater attention as the Doha Round moves forward. I believe that effort can be successful and that WTO Members can create a more comprehensive legal system for the global market, including rules on service subsidie

Generally covariant quantum information

The formalism of covariant quantum theory, introduced by Reisenberger and Rovelli, casts the description of quantum states and evolution into a framework compatible with the principles of general relativity. The leap to this covariant formalism, however, outstripped the standard interpretation used to connect quantum theory to experimental predictions, leaving the predictions of the theory ambiguous. In particular, the absence of a pre-defined time variable or background causal structure resulted in an ``order of projections ambiguity, in which the usual rule for multiple-measurement probabilities (obtained by time-ordered projections) is not defined. Equally troublesome, the probability postulate of Reisenberger and Rovelli fails to reproduce the Born interpretation for the case of simple quantum mechanical systems. Here, we develop an alternative quantum measurement formalism, based on basic principles of quantum information. After reviewing how this can be done in the context of the traditional formulation of quantum mechanics and noting its implications for the quantum measurement problem, we find that this approach can be generalized to the covariant setting, where it essentially solves the correspondence problems of covariant quantum theory. We show explicit agreement with the Born interpretation of standard quantum mechanics in the context of simple systems. We also demonstrate the origin of the quantum mechanical arrow of time within our framework, and use this to solve the order of projections ambiguity. In addition to compatibility with general covariance, we show that our framework has other attractive and satisfying features - it is fully unitary, realist, and self-contained. The full unitarity of the formalism in the presence of measurements allows us to invoke time-reversal symmetry to obtain new predictions closely related to the quantum Zeno effect

Post-Uruguay Round GATT/WTO Dispute Settlement: Substance, Strengths, Weaknesses, and Causes for Concern

Dispute settlement under the General Agreement on Tariffs and Trade (“GATT”) has come under increasing strain in recent years. The major powers often ignore GATT dispute settlement decisions which do not comport with their economic interests. This situation undermines the credibility of the GATT and threatens the system\u27s framework. If dispute settlement under the GATT continues to be ineffective as it has been through much of the 1980s and early 1990s, GATT member states (“Members”) may well lose faith in the system, begin reimposing the tariffs that were present before the GATT, thereby risking worldwide trade war and possibly consequences as serious as the Great Depression. [FN1] A primary purpose of the Uruguay Round was revision of the GATT dispute settlement system. This paper analyzes the GATT dispute settlement system arising *170 out of the Uruguay Round. The paper initially examines many of the weaknesses existing in the pre-Uruguay Round GATT dispute settlement system, on both theoretical and empirical levels. The paper then discusses the post-Uruguay Round dispute settlement system and how this system attempts to rectify certain weaknesses of the previous system. Finally, the paper discusses problems of the new dispute settlement system, and comments on some implications of these weaknesses. The paper concludes that the Uruguay Round modifications to the GATT dispute settlement system were incomplete and fail to solve certain core problems

Towards real-time agreements

In this paper, we deal with the problem of real-time coordination with the more general approach of reaching real-time agreements in MAS. Concretely, this work proposes a real-time argumentation framework in an attempt to provide agents with the ability of engaging in argumentative dialogues and come with a solution for their underlying agreement process within a bounded period of time. The framework has been implemented and evaluated in the domain of a customer support application. Concretely, we consider a society of agents that act on behalf of a group of technicians that must solve problems in a Technology Management Centre (TMC) within a bounded time. This centre controls every process implicated in the provision of technological and customer support services to private or public organisations by means of a call centre. The contract signed between the TCM and the customer establishes penalties if the specified time is exceeded. 2012 Elsevier Ltd. All rights reserved.This work is supported by the Spanish Government grants TIN2009-13839-C03-01 [CONSOLIDER-INGENIO 2010 CSD2007-00022, and TIN2012-36586-C03-01] and by the GVA project [PRO-METEO 2008/051].Navarro Llácer, M.; Heras Barberá, SM.; Botti Navarro, VJ.; Julian Inglada, VJ. (2013). Towards real-time agreements. Expert Systems with Applications. 40(10):3906-3917. https://doi.org/10.1016/j.eswa.2012.12.087S39063917401