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The modern distributed systems have not only functional requirements (i.e. Absence of deadlock, live lock etc.) but also have non-functional requirements (i.e. Security, reliability, performance, Quality of Service (QoS) etc.). The methods for checking their correctness and analyze their performance is at very primitive stage. In the last few decades, formal verification techniques such as process...
Stochastic simulations frequently exhibit behaviors that are difficult to recreate and analyze, owing largely to the stochastics themselves, and consequent program dependency chains that can defy human reasoning capabilities. We present a novel approach called Markov Chain Execution Traces (MCETs) for efficiently representing sampled stochastic simulation execution traces and ultimately driving semiautomated...
Cloud based services may experience changes - internal, external, large, small - at any time. Predicting and quantifying the effects on the quality-of-service during and after a change are important in the resiliency assessment of a cloud based service. In this paper, we quantify the resiliency of infrastructure-as-a-service (IaaS) cloud when subject to changes in demand and available capacity. Using...
The importance of stochasticity within biological systems has been shown repeatedly during the last years and has raised the need for efficient stochastic tools. We present SABRE, a tool for stochastic analysis of biochemical reaction networks. SABRE implements fast adaptive uniformization, a direct numerical approximation algorithm for computing transient solutions of biochemical reaction networks...
In this paper, we propose a translation-based approach for performance prediction of composite service built on WS-CDL. To translate a composite service into a state-transition model for quantitative analysis, we first give a set of translation rules to map WS-CDL elements into general-stochastic-petri-nets (GSPN). Based on the GSPN representation, we introduce the prediction algorithm to calculate...
A challenging issue in performance evaluation of parallel storage systems through trace-driven simulation is to accurately characterize and emulate I/O behaviors in real applications. The correlation study of inter-arrival times between I/O requests, with an emphasis on I/O-intensive scientific applications, shows the necessity to further study the self-similarity of parallel I/O arrivals. This paper...
Concurrent processing has become the default mode of operation in on-chip systems. Silicon has become cheap enough for having hardware facilities to support very large scale concurrent processing on chip. As a result the availability and applicability of power is becoming more of a limiting factor than logic. However, the advantage of parallelism in reducing power consumption will soon become unrealistic...
In this paper, we study the performance of opportunistic content distribution in a delay-tolerant network (DTN). Our primary interest is the benefit of node cooperation on the content dissemination and we investigate thoroughly how different levels of cooperation affect the content delivery delay. The evaluation is based on two complementary approaches, analytical stochastic models (Markov chains)...
This paper investigates the dispatch polices for integrated inventory and transportation decisions. There are two different types of such police which called time-based and quantity-based polices. Considering the case of stochastic demand, the paper presents numerical results about two models. And the way of commodities management is supplied.
As a main signaling protocol for multimedia sessions in the Internet, SIP (Session Initiation Protocol) introduces a retransmission mechanism to maintain the reliability for its realtime transmission. However, retransmission will make the server overload worse. Recent collapse of SIP servers due to emergencyinduced call volume indicates that the built-in SIP overload control mechanism cannot prevent...
Online social networking is an increasingly prominent social phenomenon that has motivated much interesting research in networking. This work studies the dynamic evolvement of online social networks by a simple stochastic model that captures the inter-dependent social interactions. We show that multiple stable states exist in the evolvement of online social networks, leading to fundamental ramifications...
Peer-to-peer distributed storage systems aggregate the storage space of many peers spread over the Internet. Due to the dynamic and scalable nature of these systems, it is a challenging issue to access data in an available and reliable way through redundancy. Following the modeling methodology presented, we present the stochastic model to analyze redundancy evolution of these systems under churn....
The adaptive explicit-implicit tau-leaping method with automatic tau selection is a flexible algorithm for accelerated stochastic simulation of chemically reacting systems. It combines the advantages of different simulation schemes and is particularly useful when a system changes its dynamical behavior over time in the sense that it behaves well in some time periods but possesses stiffness in other...
Peer-to-peer storage systems aim to provide a reliable long-term storage at low cost. In such systems, peers fail continuously, hence, the necessity of self-repairing mechanisms to achieve high durability. In this paper, we propose and study analytical models that assess the bandwidth consumption and the probability to lose data of storage systems that use erasure coded redundancy. We show by simulations...
The method of stochastic state classes provides a new approach for the analysis of non-Markovian stochastic Petri nets, which relies on the stochastic expansion of the graph of non-deterministic state classes based on difference bounds matrix (DBM) which is usually employed in qualitative verification. In so doing, the method is able to manage multiple concurrent non-exponential (GEN) transitions...
This paper shows how network performance can be modeled by a stochastic process algebra which includes spatial concepts. The concepts are added to PEPA and the motivation is that location of actions or processes with respect to other parts of a system may affect the time taken by an event. First a very general spatial stochastic process algebra is presented. Locations are introduced to both actions...
In this paper we study product-form conditions for generalized stochastic Petri net models. We base our results on the reversed compound agent theorem (RCAT) that has been recently formulated in the stochastic process algebra research field. In previous works, we defined finite structured GSPN models equivalent to BCMP service stations. In this paper we prove the conditions under which it is possible...
With the rapid development of Internet and home automation technology, the Internet-based home gateway system has become the focus in embedded areas. Home gateway system is a complex system with typical business process characteristics. However, there is little research work made on it with workflow principle. Still less some achievement in analyzing the time feature of the real time system service...
As an important performance of equipment system, testability is always omitted in the traditional availability analysis. Testability design is an effective way to realize the fault detection and isolation. Determining testability index is the chief step of testability design. It needs to consider the influence factors of testability such as the requirement of system availability, reliability, maintainability,...
With the modeling technology of Petri nets-based, task logics are described in products collaborative design. With boundedness, the coverability tree algorithm of Petri net is designed. On this basis, corresponding Markov chain is constructed; the algorithm of analysis performance of stochastic Petri net is provided. Through the case, the utilization ratio of resources and design efficiency in this...
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