Agreement problems are among the most important designers of distributed systems have to cope with. A way solve them is first provide a solution Consensus problem and then reduce each agreement Consensus. This "run-time customizing" approach particularly relevant when upper layer applications several distinct problems. We investigate "compile-time automatically generate ad hoc protocols. general framework, characterized by six "versatility" parameters, defined. Appropriate instantiations...

The capability of dynamically adapting to distinct runtime conditions is an important issue when designing distributed systems where negotiated quality service (QoS) cannot always be delivered between processes. Providing fault tolerance for such dynamic environments a challenging task. Considering context, this paper proposes adaptive programming model fault-tolerant computing, which provides upper-layer applications with process state information according the current system synchrony (or...

Security issues in the IoT based CPS are exacerbated with human participation CPHS due to vulnerabilities both technologies and involvement. A holistic framework mitigate security threats IoT-based environment is presented these issues. We have developed threat model involving elements environment. Research questions, directions, ideas respect securing against collaborative attacks presented.

Supporting self-management behaviour by means of component-based architectural solutions has been the focus many current research projects. In such a context, handling unanticipated changes with no impacts in application-specific software artefacts is challenging problem. this paper, we present solution for specification and execution that decouples from autonomic-specific (non-intrusive approach) supports distributed heterogeneous environments. We describe designed components environment...

Atomic broadcast or non-blocking atomic commitment are classic agreement problems encountered when designing fault-tolerant distributed systems. Specific protocols that solve such can be designed based on a common building block, namely the consensus service. Unfortunately, problem has no deterministic solution in an asynchronous system is subject to even single process crash failure. Among solutions proposed circumvent this impossibility result, concept of unreliable failure detectors by...

A number of approaches for endowing systems with self-adaptive behavior have been proposed over the past years. Among such efforts, architecture-centric solutions explicit representation feedback loops currently advocated as a promising research landscape. Although noteworthy results achieved on some fronts, lack systematic representations architectural knowledge and effective support well-informed trade-off decisions still poses significant challenges when designing modern systems. In this...

In this paper we show that it is possible to implement a perfect failure detector P (one detects all faulty processes if and only those failed) in non-synchronous distributed system. To realize that, introduce the partitioned synchronous system (Spa) weaker than conventional From some properties (such as strong synchrony) must be valid Spa trivially implementable Timeliness oracle, how Spa. Moreover, even synchrony not valid, are still able take advantage of existing partitions for improving...

Castro and Liskov proposed in 1999 a successful solution for byzantine fault-tolerant replication, named PBFT, which overcame performance drawbacks of earlier faulttolerant replication protocols. Other proposals extended PBFT with further optimizations, improving certain conditions. One the key optimizations PBFT-based protocols is use request batching mechanism. If target distributed system dynamic, that is, if its underlying characteristics change dynamically, such as workload, channel...

The capacity to detect component failures is an important characteristic for fault-tolerant distributed systems. This article presents a failure detector suitable Vehicular Ad hoc NETworks (VANETs) environments. composed of two parts: the communication link and process failure. While verifies validity between processes, process' adapts itself mobility vehicles variations in load network. Simulation results show that low number false suspicions short detection time.

In order to provide upper-layer applications with continuous message delivery and updated information on membership changes - due process failures, leaves joins -, group communication protocols must exchange messages continuously monitor all members, which in certain load conditions may incur unacceptable overhead the underlying system. Therefore, design of such deal trade-off between performance requirements as speed (e.g., latency) cost overhead). However, when behavior computing...

We present the concept of mobile groups as a basic mechanism for both reliable migration and coordination processes. Analogously to traditional group systems, also provide message delivery guarantees virtual synchrony. Furthermore, they make process mobility not only visible group, but consistently ordered with other actions (such crashes, joins, leaves, migrations). The approach represents novel support which can be used handle reliability distributed systems agent systems), at application...

The capability of dynamically adapting to distinct runtime conditions is an important issue when designing distributed systems where negotiated quality service (QoS) cannot always be delivered between processes. Providing fault-tolerance for such dynamic environments a challenging task. Considering context, this paper proposes adaptive model fault-tolerant computing. This encompasses both the synchronous (where there are time bounds on processing speed and message delay) asynchronous no...

The new requirements of modern real-time distributed supervision and control systems such as more flexibility, interoperability, cost savings, have motivated the use software-intensive solutions both in academia industry. Following this trend we presented, a previous publication, design rationale implementation issues flexible reusable software platform (ARCOS) that relies on CORBA component model (CCM/CIAO), DAIS (data acquisition from industrial systems) standard, framework technologies....

Endowing software systems with self-adaptation capabilities has shown to be quite effective in coping uncertain and dynamic operational environments as well managing the complexity generated by non-functional requirements. Nowadays, a large number of approaches tackle issue enabling self-adaptive behavior from different perspectives under diverse assumptions, making it harder for architects make judicious decisions about design alternatives quality attributes tradeoffs. It currently been...