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There has been much recent interest in Private information Retrieval (PIR) in models where a database is stored across several servers using coding techniques from distributed storage, rather than being simply replicated. In particular, a recent breakthrough result of Fazelli, Vardy and Yaakobi introduces the notion of a PIR code and a PIR array code, and uses this notion to produce efficient protocols...
With the development of cloud services, outsourcing computation tasks to a commercial cloud server has drawn attentions by various communities, especially in the Big Data age. Public verifiability offers a flexible functionality in real circumstance where the cloud service provider (CSP) may be untrusted or some malicious users may slander the CSP on purpose. However, sometimes the computational result...
Apache ZooKeeper is a distributed data storage that is highly concurrent and asynchronous due to network communication, testing such a system is very challenging. Our solution using the tool "Modbat" generates test cases for concurrent client sessions, and processes results from synchronous and asynchronous callbacks. We use an embedded model checker to compute the test oracle for non-deterministic...
The use of Cloud computing keeps increasing day after day due to the unique combination of characteristics that the cloud introduce, including: on-demand self-service, broad network access, resource pooling, rapid elasticity and measured service. Though, from forensics experts' point of view, many challenges are faced when responding to incidents that have occurred in a cloud computing ecosystem....
This work is about imitating modeling of functioning technology of two LAN organized on the basis of AsteriskNow, presented as two knots divided among themselves by a certain distance with use of the software package into NetCracker 4.1. Development of the imitating model consisting of two or more knots removed on distance from each other and definition like a traffic between knots, parameters of...
To deal with real-life black-box expensive multiobjective optimization problems, we investigated the application of an optimization framework expanded from MOEA/D-EGO. As MOEA/D-EGO, Gaussian process modeling techniques are used to subtittute the evaluation of the problem itself. Apart from the expected improvement (EI) in-fill rule in the original MOEA/D-EGO, we define a process that adaptively selects...
Password-based user authentication service is widely used in Internet. Most of the password-based authentication protocols are constructed under the single-server structure that a authencitation server stores cleartext passwords or verification data derived from password and responds to users' authentication request. The security of single-server authentication system is very fragile. In particular,...
Virtual Machine (VM) placement is an important research area for power conservation in data centers. In this paper, we introduce a hybrid queuing model for VM placement for data centers to improve total placement time and earn more revenue. For the large data center management smaller placement times lead to greater quality of service (QoS) experienced by an user of the cloud infrastructure. Similarly,...
Advanced modeling and simulation has enabled the design of a variety of innovative products and the analysis of numerous complex phenomenon. However, significant barriers exist to widespread adoption of these tools. In particular, advanced modeling and simulation: (1) is considered complex to use, (2) needs in-house expertise, and (3) requires high capital costs. In this paper, we describe the development...
The demand for parallel I/O performance continues to grow. However, modelling and generating parallel I/O work-loads are challenging for several reasons including the large number of processes, I/O request dependencies and workload scalability. In this paper, we propose the PIONEER, a complete solution to Parallel I/O workload characterization and gEnERation. The core of PIONEER is a proposed generic...
An Internet web application is comprised of dynamic web objects that are updated from time to time. This work investigates the placement of web objects over multi-tier servers in which each host can obtain an object by constructing locally, or via a network transmission from the upstream host. The cost of maintaining web objects consists of the computing resources used for constructing objects as...
Performance bugs that don't cause fail-stop errors but degradation of system performance have been one of the most fundamental issues in the production platform. How to effectively online detect bugs becomes more and more urgent for engineers. Performance bugs usually manifest themselves as the anomalous call structures of request traces or anomalous latencies of invoked methods. In this paper, we...
Captures of IP traffic contain much information on very different kinds of activities like file transfers, users interacting with remote systems, automatic backups, or distributed computations. Identifying such activities is crucial for an appropriate analysis, modeling and monitoring of the traffic. We propose here a notion of density that captures both temporal and structural features of interactions,...
Since Trojan has been used widely in various applications, modern Trojan requires a stronger anti-tracing performance than before. As an attempt seeking beneficial result, this paper proposes a new Trojan communication model based on Internet Relay Chat (IRC) and Webmail system. IRC chat channel is designed to transfer commands and Webmail system is applied to store data. Because of this design, it...
Many network services such as email services and online social networking applications offer enhanced capabilities to standard communication services by mining user data. Examples of such services are friend suggestions, marketing recommendations, etc. In this paper, we look at enhancing related people or a simple contacts application by inferring a dynamic set of relevant people for users at any...
Due to the recent spread of streaming delivery of movies, streaming using Peer-to-Peer (P2P) streaming technology has attracted much attention. In P2P streaming systems, to distribute the network load, peers from which the user receives data is selected at random. For this, clients have to wait until their desired data is delivered. Therefore, there are many researches to reduce the waiting time....
In this paper, we propose simple performance models to predict the impact of consolidation on the storage I/O performance of virtualized applications. We use a measurement-based approach based on tools such as blktrace and tshark for storage workload characterization in a commercial virtualized solution, namely VMware ESX server. Our approach allows a distinct characterization of read/write performance...
The paper proposes to simulate feasibility of using virtualization technology to auto-scaling problem in cloud computing. It uses ARENA simulation software to build two different models. There are auto-scaling without server virtualization and auto-scaling with server virtualization. The results of our experiment show that employing virtualization technology increases both life time of servers and...
Measuring trust among social network users is an important research issue. In this paper, we present a new trust model based on emails. We name this new trust model as Email Trust (EMT). EMT is constructed based on the interactions among users via their daily emails, which provides a level of belief on the data transmitted by a use. In EMT, we require each user to perform a trust checking procedure...
Personal Space of Information (PSI) is the whole information collection about or of the person which can be the important resource to mine personal competence, personal task and corresponding required knowledge which can be converted to the evidence of individual competence and update the competence model. This paper analysis the character of PSI and introduces the method of competence modeling automatically...
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