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

Analisis Terciptanya Transisi Kepemimpinan Baru Dalam Perhelatan Pilkada Ponorogo Dilihat Dari Perspektif Masyarakat

The implementation of the Ponorogo regional election in 2020 is indeed in a special atmosphere, considering that two competitor pairs of candidates are fighting for people’s sympathies in order to grab seat number 1 in Ponorogo. In welcoming the people’s democratic party, the hot atmosphere is identical to be found in the field. Regional election is a prestigious event to determine the fate of the region for the next 5 years, so that all parties are competing to give their best. In Ponorogo, both of successful team and volunteers from both pairs of candidates showed enthusiasm and support in many ways interestingly, the competition in the Ponorogo regional election was between two old competitors namely Sugiri Sancoko VS Ipong Muchlissoni where in the previous regional election (2015) had heated up to a dispute over the election results. A new chapter has begun, but the atmosphere of competition is certainly more heated for both sides. The leadership note of the regent of Ipong Muhclissoni is a major highlight, which has been felt by the people of Ponorogo through experience and understanding over the past 5 years. This researches aims to narrow the perspective of society, so that it provides a concrete picture of two possibilities, namely: the emergence of a new leader, or retaining an old leader. Because officially in the Ponorogo regional election in 2020 there are only two candidates, it is very interesting to conduct this research.          Keywords : Transition, Leadership, Regional Electio

Pilkada Serentak, Eksklusi Partai Politik, dan Masa Depan Politik Representasi

Since the beginning of its implementation, direct local election has brought great expectation to perform radical changes in fulfilling the political rights of public to determine local political leader in their region. This expectation gained momentum from the contestation of national versus local political discourse, that created direct local election as new field of discursively to build local political power. Meanwhile, various researches on direct local election have found that the high expectation of political freedom actually had been 'hijacked' by political oligarchy that made direct local elections very expensive event, but could not be guaranteed to increase public welfare. The concurrent local elections, which will be held for the first time at the end of year 2015, become new field of discursively to overcome the public apathy. This paper positions concurrent local elections as discursive struggle that established figure-based politics as hegemonic discourse and at the same time, excluded political parties within the discourse, through the dislocations of meaning, that define simultaneity as instrumental arrangement. The exclusion of political parties is also dislocated because this involvement is understood only as 'political vehicle' or formalistic institution for candidacy. These dislocated meanings evoked a question, whether concurrent local elections could create new form of political representation, or in fact, establish figure-based politics hegemony that actually challenge democratization

Brief Announcement: Fault-Tolerant Shape Formation in the Amoebot Model

The amoebot model is a distributed computing model of programmable matter. It envisions programmable matter as a collection of computational units called amoebots or particles that utilize local interactions to achieve tasks of coordination, movement and conformation. In the geometric amoebot model the particles operate on a hexagonal tessellation of the plane. Within this model, numerous problems such as leader election, shape formation or object coating have been studied. One area that has not received much attention so far, but is highly relevant for a practical implementation of programmable matter, is fault tolerance. The existing literature on that aspect allows particles to crash but assumes that crashed particles do not recover. We propose a new model in which a crash causes the memory of a particle to be reset and a crashed particle can detect that it has crashed and try to recover using its local information and communication capabilities. We propose an algorithm that solves the hexagon shape formation problem in our model if a finite number of crashes occur and a designated leader particle does not fail. At the heart of our solution lies a fault-tolerant implementation of the spanning forest primitive, which, since other algorithms in the amoebot model also make use of it, is also of general interest