SPNP, a powerful GSPN package that allows the modeling of complex system behaviors, is presented. Advanced constructs are available in SPNP such as marking-dependent arc multiplicities, enabling functions, arrays places or transitions, and subnets; full expressive power C programming language also to increase flexibility net description. Sophisticated steady-state transient solvers including cumulative up-to-absorption measures. The user not limited predefined set measures; detailed...

In a client-server type system, the server software is required to run continuously for very long periods. Due repeated and potentially faulty usage by many clients, such "ages" with time eventually fails. (Huang et al., 1995) proposed technique called "software rejuvenation" in which periodically stopped then restarted "robust" state after proper maintenance. This "renewal" of prevents (or at least postpones) crash failure. As lost cost incurred) due failure typically more than...

This paper develops an availability model of a virtualized system. We construct non-virtualized and two hosts system models using two-level hierarchical approach in which fault trees are used the upper level homogeneous continuous time Markov chains (CTMC) to represent sub-models lower level. In models, we incorporate not only hardware failures (e.g., CPU, memory, power, etc) but also software including Virtual Machine Monitor (VMM), (VM), application failures. high (HA) service VM live...

ABSTRACT Attack tree (AT) is one of the widely used non‐state‐space models for security analysis. The basic formalism AT does not take into account defense mechanisms. Defense trees (DTs) have been developed to investigate effect mechanisms using measures such as attack cost, investment return on (ROA), and (ROI). DT, however, places only at leaf nodes corresponding ROI/ROA analysis incorporate probabilities attack. In response (ART), are both captured but ART suffers from problem...

Handling diverse client demands and managing unexpected failures without degrading performance are two key promises of a cloud delivered service. However, evaluation service quality becomes difficult as the scale complexity system increases. In environment, request from user goes through variety provider specific processing steps instant it is submitted until fully delivered. Measurement-based expensive especially if many configurations, workload scenarios, management methods to be analyzed....

Quite often failures in network based services and server systems may not be accidental, but rather caused by deliberate security intrusions. We would like such to either completely preclude the possibility of a intrusion or design them robust enough continue functioning despite attacks. Not only is it important prevent tolerate intrusions, equally treat as QoS attribute at par with, if more than other attributes availability performability. This paper deals with various issues related...

M.D. Beaudry (1978) proposed a simple method of computing the distribution performability in Markov reward process. Two extensions Beaudry's approach are presented. The authors generalize to semi-Markov process by removing restriction requiring association zero absorbing states only. algorithm proceeds replacing nonabsorbing probabilistic switch; it is therefore related elimination vanishing from reachability graph generalized stochastic Petri net and fast transient decomposition stiff...

Finite population and finite capacity polling systems are considered. The behavior of these is described by means generalized stochastic Petri nets. exact results for the mean response times obtained numerically a net package. generally difficult to analyze. can be used validate approximate solutions above class when such become available.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

There is a need to quantify system properties methodically. Dependability and security models have evolved nearly independently. Therefore, it crucial develop classification of dependability which can meet the requirement professionals in both fault-tolerant computing community. In this paper, we present new models. First threats mitigations systems networks. And then several individual model types such as availability, confidentiality, integrity, performance, reliability, survivability,...

Attack tree (AT) is one of the widely used combinatorial models in cyber security analysis. The basic formalism AT does not take into account defense mechanisms. Defense trees (DT) have been developed to investigate effect mechanisms using measures such as attacker's cost and cost, return on investment (ROI) attack (ROA). DT, however, places only at leaf node level while corresponding ROI/ROA analysis incorporate probability attack. In response (ART), attacker-defender game was fin optimal...

A new algorithm based on binary decision diagram (BDD) for the analysis of a system with multistate components is proposed. Each state component represented by boolean variable, and series fault trees. Boolean algebra restrictions variables used to address dependence among these that collectively represent same BDD operation proposed realize this algebra. Due nature BDD, sum disjoint products (SDP) can be implicitly represented, which avoids huge storage high computational complexity large...

As server virtualization is used as an essential software infrastructure of various services such cloud computing, availability management virtualized system becoming more significant. Although time-based rejuvenation useful to postpone/prevent failures due aging in a system, the schedules for virtual machine (VM) and monitor (VMM) need be determined proper way VM availability, since VMM affects VMs running on VMM. This paper presents analytic models using stochastic reward nets three...

In the past ten years, software aging phenomenon has been systematically researched, and recognized by both academic, industry communities as an important obstacle to achieving dependable systems. One of its main effects is depletion operating system resources, causing performance degradation or crash/hang failures in running applications. When conducting experimental studies evaluate operational reliability systems suffering from aging, long periods runtime are required observe failures....

Server virtualization is a technology used in many enterprise systems to reduce operation and acquisition costs, increase the availability of their critical services. Virtualized may be even more complex than traditional nonvirtualized systems; thus, quantitative assessment system difficult. In this paper, we propose sensitivity analysis approach find parameters that deserve attention for improving systems. Our based on Markov reward models, suggests host failure rate most important...

Infrastructure as a Service (IaaS) is one of the most significant and fastest growing fields in cloud computing. To efficiently use resources an IaaS cloud, several important factors such performance, availability, power consumption need to be considered evaluated carefully. Evaluation these metrics essential for cost-benefit prediction quantification different strategies which can applied management. In this paper, analytical models based on Stochastic Reward Nets (SRNs) are proposed model...

The need for high reliability, availability and performance has significantly increased in modern applications, that handle rapidly growing demands while providing uninterruptible services. Cloud computing systems fundamentally provide access to large pools of data computational resources. Eucalyptus is a software framework largely used implement private clouds hybrid-style Infrastructure as Service. It implements the Amazon Web Service (AWS) API, allowing interoperability with other...

The authors examine the problem of accurately modeling software fault-tolerance technique based on recovery blocks. Analysis some systems have investigated correlation between modules, which may be due to a portion functional specification that is common all or inherent hardness problems. Three types dependence can captured using measurements are considered. These modules for single input, successive acceptance tests correct module outputs and incorrect outputs, subsequent inputs. authors'...