Event-Based and Publish/Subscribe Communication

2011 ◽  
pp. 152-171 ◽  
Author(s):  
Erwin Aitenbichler
Keyword(s):  
Distributed Systems ◽  
Ubiquitous Computing ◽  
Mobile Networks ◽  
Filter Model ◽  
Interaction Models ◽  
Network Availability ◽  
Program Flow ◽  
Event Based ◽  
Full Network

Ubiquitous Computing assumes that users and their computing devices are highly mobile. Because it is unlikely that mobile networks will be equally available in the same quality everywhere, there may be varying levels of connectivity, ranging from full network availability through low-bandwidth connectivity, to no connection at all. As a consequence, software components in the system cannot assume that the connections between them are static and always available. The event-based style is essential for ubiquitous computing, since it offers a good decoupling of the communicating entities in terms of space, time, and program flow. This chapter starts with an introduction to the different interaction models found in distributed systems. Next, a classification of publish/subscribe-systems is presented. We then describe a formal data and filter model that allows us to precisely define the semantics of event filters. Based on this model, we discuss different routing algorithms for the efficient distribution of event notifications in a network. Finally, a number of examples for publish/subscribe systems are presented.

Reports on categorization and classification of human rights violations in Chile (1974–1978)

2018 ◽  
Vol 30 (1) ◽  
pp. 44-63 ◽  
Author(s):  
Marcela Ruiz ◽  
Oriana Bernasconi
Keyword(s):  
Human Rights ◽  
Political Violence ◽  
Social Recognition ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Legal Perspective ◽  
Communicative Process ◽  
Event Based ◽  
The Relationship

This study analyzes socio-discursive categories used to define and classify the political violence exerted in Chilean human rights reports (1974–1978) to understand the emergence of the repertoire of repression and the construction of victimhood as a social recognition and communicative process in Latin America during the 1970s. These reports are addressed as a professional discursive genre produced by non-governmental organizations whose purpose is to denounce the violation of human rights in the context of political controversies as well as in the Chilean totalitarian context. The discursive genre is characterized by objectivity, the credibility of the information, the event-based approach, the use of statistics to establish the type and magnitude of the violation of human rights. The corpus analyzed consists of 44 reports belonging to human rights archives. The statistical section and comments were coded according to narrative categories (participants, action, cause, time and space). The results show the predominance of the legal perspective to classify the violation of human rights, the emergence of the category of enforced disappearance, the relationship with the socio-political context and the categories elaborated to identify patterns of violation of human rights.

Panel

2010 ◽  
pp. 432-454
Author(s):  
Annika Hinze ◽  
Jean Bacon ◽  
Alejandro Buchmann ◽  
Sharma Chakravarthy ◽  
Mani Chandi ◽  
...  
Keyword(s):  
Distributed Systems ◽  
Sensor Networks ◽  
Panel Discussion ◽  
Streaming Data ◽  
The Other ◽  
Software Architectures ◽  
Pros And Cons ◽  
Basic Concepts ◽  
Event Based

This chapter is a panel discussion in writing. The field of event-based systems finds researchers from a number of different backgrounds: distributed systems, streaming data, databases, middleware, and sensor networks. One of the consequences is that everyone comes to the field with a slightly different mindset and different expectations and goals. In this chapter, we try to capture some of the voices that are influential in our field. Seven panellists from academia and industry were invited to answer and discuss questions about event-based systems. The questions were distributed via email, to which each participant replied their initial set of answers. In a second round every panelist was given the opportunity to expand their statement and discuss the contributions of the other panellists. The questions asked can be grouped into two types. Questions in the first group refer to each participant’s understanding of the basic concepts of event-based systems (EBS), the pros and cons of EBS, typical assumptions of the field and how they understood EBS to fit into the overall landscape of software architectures. The second group of questions pointed to the future of EBS, possible killer applications and the challenges that EBS researchers in academia and industry need to address in the medium and long term. The next section gives each panellist’s initial statements as well as their comments to other participants’ contributions. Each participant’s section starts with a short introduction of the panellist and their work. In the final section, we compare and reflect on the statements and discussions that are presented by the seven panellists.

Distributed Systems

2020 ◽  
pp. 143-198
Author(s):  
Andreas Bolfing
Keyword(s):  
Distributed Systems ◽  
Fault Tolerant ◽  
Deterministic Algorithm ◽  
Impossibility Result ◽  
Software Systems ◽  
Trade Off ◽  
Byzantine Failures ◽  
The Individual ◽  
Special Case

Chapter 5 considers distributed systems by their properties. The first section studies the classification of software systems, which is usually distinguished in centralized, decentralized and distributed systems. It studies the differences between these three major approaches, showing there is a rather multidimensional classification instead of a linear one. The most important case are distributed systems that enable spreading of computational tasks across several autonomous, independently acting computational entities. A very important result of this case is the CAP theorem that considers the trade-off between consistency, availability and partition tolerance. The last section deals with the possibility to reach consensus in distributed systems, discussing how fault tolerant consensus mechanisms enable mutual agreement among the individual entities in presence of failures. One very special case are so-called Byzantine failures that are discussed in great detail. The main result is the so-called FLP Impossibility Result which states that there is no deterministic algorithm that guarantees solution to the consensus problem in the asynchronous case. The chapter concludes by considering practical solutions that circumvent the impossibility result in order to reach consensus.

Fast Data Processing for Large-Scale SOA and Event-Based Systems

2015 ◽  
Vol 5 (4) ◽  
pp. 54-77
Author(s):  
Marcel Tilly ◽  
Stephan Reiff-Marganiec
Keyword(s):  
Data Processing ◽  
Information Flow ◽  
Mobile Networks ◽  
Large Scale ◽  
New Concepts ◽  
Combining Data ◽  
Access To Data ◽  
Processing Techniques ◽  
Event Based ◽  
The Internet Of Things

The deluge of intelligent objects that are providing continuous access to data and services on one hand and the demand of developers and consumers to handle these data on the other hand require us to think about new communication paradigms and middleware. In hyper-scale systems, such as in the Internet of Things, large scale sensor networks or even mobile networks, one emerging requirement is to process, procure, and provide information with almost zero latency. This work is introducing new concepts for a middleware to enable fast communication by limiting information flow with filtering concepts using policy obligations and combining data processing techniques adopted from complex event processing.

Trust and Accountability

2011 ◽  
pp. 363-389 ◽  
Author(s):  
Sebastian Ries
Keyword(s):  
Distributed Systems ◽  
Ubiquitous Computing ◽  
Computer Science ◽  
Everyday Life ◽  
Social Life ◽  
The State ◽  
Short Overview ◽  
Networked Computers

Ubiquitous computing implies that literally any activity in everyday life can be assisted or accompanied by networked computers. Therefore, the concepts of everyday social life must be carefully reflected on when developing applications for ubiquitous computing. The present chapter focuses on the concepts of trust and accountability. First, both concepts are introduced with their everyday semantics. Second, we explain why trust is relevant for ubiquitous computing, and introduce the main issues for dealing with trust in computer science. Third, we show how accountability can be achieved in distributed systems using reputation and micropayment mechanisms. In both sections, we provide a short overview of the state-ofthe- art and give detailed examples for a deeper understanding. Finally, we provide a research outlook, again arguing for the integration of these concepts into future ubiquitous computing applications.

scholarly journals Network architecture test-beds as platforms for ubiquitous computing

2008 ◽  
Vol 366 (1881) ◽  
pp. 3709-3716 ◽  
Author(s):  
Timothy Roscoe
Keyword(s):  
Distributed Systems ◽  
Ubiquitous Computing ◽  
Network Architecture ◽  
Overlay Networks ◽  
Research Community ◽  
The Internet ◽  
Internet Architecture ◽  
Systems Research ◽  
Disruptive Change ◽  
Fundamental Design

Distributed systems research, and in particular ubiquitous computing, has traditionally assumed the Internet as a basic underlying communications substrate. Recently, however, the networking research community has come to question the fundamental design or ‘architecture’ of the Internet. This has been led by two observations: first, that the Internet as it stands is now almost impossible to evolve to support new functionality; and second, that modern applications of all kinds now use the Internet rather differently, and frequently implement their own ‘overlay’ networks above it to work around its perceived deficiencies. In this paper, I discuss recent academic projects to allow disruptive change to the Internet architecture, and also outline a radically different view of networking for ubiquitous computing that such proposals might facilitate.

Generalized Models for the Classification of Abnormal Movements in Daily Life and its Applicability to Epilepsy Convulsion Recognition

2016 ◽  
Vol 26 (06) ◽  
pp. 1650037 ◽  
Author(s):  
José R. Villar ◽  
Paula Vergara ◽  
Manuel Menéndez ◽  
Enrique de la Cal ◽  
Víctor M. González ◽  
...  
Keyword(s):  
Fuzzy Systems ◽  
Classification Error ◽  
Support Vector ◽  
False Alarms ◽  
Abnormal Movements ◽  
Vector Machines ◽  
Clonic Convulsions ◽  
Event Based ◽  
Validation Scheme

The identification and the modeling of epilepsy convulsions during everyday life using wearable devices would enhance patient anamnesis and monitoring. The psychology of the epilepsy patient penalizes the use of user-driven modeling, which means that the probability of identifying convulsions is driven through generalized models. Focusing on clonic convulsions, this pre-clinical study proposes a method for generating a type of model that can evaluate the generalization capabilities. A realistic experimentation with healthy participants is performed, each with a single 3D accelerometer placed on the most affected wrist. Unlike similar studies reported in the literature, this proposal makes use of [Formula: see text] cross-validation scheme, in order to evaluate the generalization capabilities of the models. Event-based error measurements are proposed instead of classification-error measurements, to evaluate the generalization capabilities of the model, and Fuzzy Systems are proposed as the generalization modeling technique. Using this method, the experimentation compares the most common solutions in the literature, such as Support Vector Machines, [Formula: see text]-Nearest Neighbors, Decision Trees and Fuzzy Systems. The event-based error measurement system records the results, penalizing those models that raise false alarms. The results showed the good generalization capabilities of Fuzzy Systems.

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