Green Cloud Provisioning Throughout Cooperation of a WDM Wide Area Network and a Hybrid Power IT Infrastructure

The paper focuses on cooperation between cloud and network operators, as well as on fitting particular routing strategies to various cloud services. Three cooperation models are presented, analyzed and compared in the paper: the proposed model and two widely used reference models. The main difference between the models is the set of information being exchanged between the involved parties. Additionally, we analyze the applicability of four fitting schemas for each considered model. It is shown that the proposed model, alongside with an appropriate fitting schema, is able to reduce the blocking probability of cloud services requests. At the same time, thanks to the use of green anycast strategies, it is able to significantly reduce carbon dioxide emission.     

Taking back control of privacy: a novel framework for preserving cloud-based firewall policy confidentiality

As the cloud computing paradigm evolves, new types of cloud-based services have become available, including security services. Some of the most important and most commonly adopted security services are firewall services. These cannot be easily deployed in a cloud, however, because of a lack of mechanisms preserving firewall policy confidentiality. Even if they were provided, the customer traffic flowing through the Cloud Service Provider infrastructure would still be exposed to eavesdropping and information gaining by performing analysis. To bypass these issues, the following article introduces a novel framework, known as the Ladon Hybrid Cloud, for preserving cloud-based firewall policy confidentiality. It is shown that in this framework, a high level of privacy is provided thanks to leveraging an anonymized firewall approach and a hybrid cloud model. A number of optimization techniques, which help to further improve the Ladon Hybrid Cloud privacy level, are also introduced. Finally, analysis performed on the framework shows that it is possible to find a trade-off between the Ladon Hybrid Cloud privacy level, its congestion probability, and efficiency. This argument has been demonstrated through the results of conducted experiments.     

Experience-Driven Model of Decision-Making Processes in Project Teams

This article presents a model of decision-making processes in project teams. Project teams constitute a specific type of organization appointed to implement a project. Decisions made by project teams result from the methods of project management and best management practices. The authors have undertaken the task of formalizing these processes using the classical method of constructing decision trees. It has been established that this method cannot be fully exploited because the decision-making paths need changing (the decision tree must be dynamically generated after every decision). Therefore, the authors applied a method for collecting experiences, the Set of Experience Knowledge Structure (SOEKS), to support the structure of a decision tree. This method was used to support decision-making processes regarding the selection of methods and technologies of project management and to classify the location decisions resulting from exceeding levels of particulate matter.     

GC-MS and 13C NMR Investigation of Lead Zirconate Titanate Precursor Sols for Fiber Preparation

Different macroscopic properties of PZT fibers have been obtained when using acetic acid and methacrylic acid to modify the PZT precursor. In order to clarify the role of the acids the molecular structure of the acidified PZT precursors was investigated and compared by gas chromatography-mass spectrometry, Fourier transform infrared, ¹³C nuclear magnetic resonance (NMR) spectroscopy (solution and solid state ¹³C NMR) and the reason for obtaining long PZT fibers is discussed. The results indicate that when methacrylic acid was used, long gel and ceramic fibers have been obtained because strongly co-ordinating carboxylate groups of methacrylic acid were formed. Linear chains, like those of methacrylic acid propyl ester and methacrylic acetate, have been formed in the PZT precursor sols. In addition, after heat treatment the polymer decomposed quickly so that pure perovskite could be obtained at low temperature in the PZT fibers. When acetic acid was used short fibers were obtained. Acetic acid may act as chelate agent to form oxo acetate in the precursors; this oxo acetate nature also resulted in PZT fibers drawing. However, the longest gel and ceramic fibers have been prepared from precursors with methacrylic acid.     

Growth of novel carbon phases by methane infiltration of free-standing single-walled carbon nanotube films

High-temperature methane infiltration of thin, free-standing films of acid-treated single-walled carbon nanotubes (SWCNT) has been studied by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. In the early stages of infiltration, carbon nuclei form predominantly at SWCNT bundle intersections. Further growth proceeds via the formation of graphite nanosheets - without further influence of the nanotube support. Both sheet edges and their structural imperfections act as reaction centers for subsequent deposition, likely giving rise to autocatalytic deposition kinetics. In contrast, infiltration with a H₂:CH₄ (24:1) mixture leads to the reductive activation of residual Ni/Co impurities embedded in the precursor SWCNT-felt. This is associated with a different predominant carbon deposition mode in which multiwalled carbon nanotubes grow out from the substrate.     

SpaDeS: Detecting spammers at the source network

Despite the large variety and wide adoption of different techniques to detect and filter unsolicited messages (spams), the total amount of such messages over the Internet remains very large. Some reports point out that around 80% of all emails are spams. As a consequence, significant amounts of network resources are still wasted as filtering strategies are usually performed only at the email destination server. Moreover, a considerable part of these unsolicited messages is sent by users who are unaware of their spamming activity and may thus inadvertently be classified as spammers. In this case, these oblivious users act as spambots, i.e., members of a spamming botnet. This paper proposes a new method for detecting spammers at the source network, whether they are individual malicious users or oblivious members of a spamming botnet. Our method, called SpaDeS, is based on a supervised classification technique and relies only on network-level metrics, thus not requiring inspection of message content. We evaluate SpaDeS using real datasets collected from a Brazilian broadband ISP. Our results show that our method is quite effective, correctly classifying the vast majority (87%) of the spammers while misclassifying only around 2% of the legitimate users.     

Rapid tooling aided by reverse engineering to manufacture EDM electrodes

The present work deals with the application of indirect rapid tooling (RT) technology to manufacture electrical discharge machining (EDM) copper electrodes from investment casting, with wax prototypes made by ThermoJet 3D printing, a rapid prototyping (RP) technique. The reverse engineering (RE) method is utilised to transform the point cloud data of an object surface, obtained from 3D digitising, in a 3D CAD surface model dataset. The methodology presented is fundamental to verify the prototype’s geometry for tooling so as to assure its metrological accuracy and to optimise foundry process parameters using finite element analysis (FEA). Based on a case study, some functional conclusions are presented for the application of RT in manufacturing EDM electrodes aided by 3D digitising and RE, validating the accomplishment by the integration of these technologies and methodologies in EDM manufacturing processes.     

Bücherschau

Ohne Zusammenfassung VDI     

Designing and building SDN testbeds for energy-aware traffic engineering services

As experimenting with energy-aware techniques on large-scale production infrastructure is prohibitive, a large number of proposed traffic engineering strategies have been evaluated only using discrete-event simulations. The present work discusses (i) challenges towards building testbeds that allow researchers and practitioners to validate and evaluate the performance and quality of energy-aware traffic engineering strategies, (ii) requirements to fulfil when porting simulations to testbeds, and (iii) two proof-of-concept testbeds. One testbed uses and provides software-defined network (SDN) services created on the open-network operating system while the other is a composition of virtual Open vSwitches controlled by the Ryu SDN framework. The aim of the testbeds is to validate previously proposed energy-aware traffic engineering strategies in different environments. We detail the platforms and illustrate how they have been used for performance evaluation. Additionally, the paper compares results obtained in the testbeds with evaluations performed using discrete-event simulations and presents challenges faced while implementing energy-aware traffic engineering mechanisms as SDN services in testbed environments.