Guilherme Sperb Machado

A Cloud Storage overlay to aggregate heterogeneous Cloud services

Many Cloud services provide generic (e.g., Amazon S3 or Dropbox) or data-specific Cloud storage (e.g., Google Picasa or SoundCloud). Although both Cloud storage service types have the data storage in common, they present heterogeneous characteristics: different interfaces, accounting and charging schemes, privacy and security levels, functionality and, among the data-specific Cloud storage services, different data type restrictions. This paper proposes PiCsMu (Platform-independent Cloud Storage System for Multiple Usage), a novel approach exploiting heterogeneous data storage of different Cloud services by building a Cloud storage overlay, which aggregates multiple Cloud storage services, provides enhanced privacy, and offers a distributed file sharing system. As opposed to P2P file sharing, where data and indices are stored on peers, PiCsMu uses Cloud storage systems for data storage, while maintaining a distributed index. The main contribution of this work is to show the feasibility to store arbitrary data in different Cloud services for private use and/or for file sharing. Furthermore, the evaluation of the prototype confirms the scalability with respect to different file sizes and also shows that a moderate overhead in terms of storage and processing time is required.

Schengen Routing: A Compliance Analysis

Schengen Routing was proposed as a countermeasure to traffic monitoring activities practiced by intelligence agencies. This work here presents the results of a larger-scale measurement performed to quantify Schengen Routing compliance in today’s Internet. Based on 3388 TCP, UDP, and ICMP traceroute measurements executed from RIPE Atlas probes located in over 1100 different Autonomous Systems (AS) in the Schengen Area, it was found that 34.5% to 39.7% of these routes are Schengen-compliant, while compliance levels vary from 0% to 80% among countries. Finally, an approach was developed that allows end-users to determine whether a specific route to a host is Schengen-compliant or not.

Measuring interactivity and geographical closeness of Online Social Network users to support social recommendation systems

Several applications (e.g., Instagram, PiCsMu) integrate existing Online Social Networks (OSN) into the core of their solutions to explore social information. Although this integration enables more accurate social recommendation systems, the collection and monitoring of relevant OSN data by third-party applications is a challenging management task, since OSNs (a) impose rate restrictions to their Application Programming Interface (API) calls, (b) do not provide detailed information about specific OSN features, and (c) may provide incomplete or not up-to-date OSN data. Therefore, this paper covers the design, prototyping, and evaluation of JSocialLib, a new meta-API library for collecting OSN data from existing OSNs. It provides (1) an interaction- and (2) a location-based method in support of social recommendations systems.

TraceMan: A Traceroute-based Measurement and Management Tool

In order to guarantee a high quality of service, service providers employ tools both inside of their own infrastructure as well as on the client end, to monitor important parameters such as availability, responsiveness and reliability of their service. TraceMan, a traceroutebased measurement and management tool, is an implementation of RFC 5388 in Java and supports the monitoring of services from an end user perspective by running traceroute measurements on distributed simulated clients. This thesis provides an overview of the design, implementation, and evaluation of the TraceMan software. The evaluation is able to support the assertion that TraceMan is capable of identifying potential network problems such as high round trip times or route changes in a test environment where 36 services were monitored from 18 simulated clients.

The Design of a Single Funding Point Charging Architecture

Most federations across the world apply Single Sign-On (SSO) Authentication and Authorization Infrastructure (AAI) platforms. Thus, access to services offered by organizations, which belong to such a federation, can be granted to their users independent of their current location. The increasing demand to charge users for those service usages lead organizations to establish various charging mechanisms. However, until today the majority of organizations is using service-dependent solutions to perform charging. This policy absorbs the utility of an SSO system, since users still have to monitor and control each credit account separately. Therefore, the approach proposed defines an extension to SSO platforms, which is consolidated, non dispersed and service-independent. A Single Funding Point Charging Architecture (SFP-CA) allows users to settle payments using funds from the same credit account, for any type of service they use inside their federation.