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Weekly Meetings

DSG is holding weekly meetings to create an space for researchers to learn and discuss about their latest findings in the area.

Weekly Meeting (backup)

In search of fairness. Critical design alternatives for Sustainability
Speakers: Tessy Cerratto Pargman and Somya Joshi
Wednesday, December 14, 2016 - 11:00
Location: C6-E101

Abstract Caught between the infinite promise unleashed by technology proliferation and the unprecedented scale of resource depletion, waste and inequity, we inhabit a space where critical alternatives are sought more than ever. As a reflection of the above, we find in HCI, a slant towards technological fixes to existing sustainability problems, as opposed to a more holistic approach that includes behavioural and societal change. It is within this context that this paper is situated, where we propose a socio-ecological approach and argue our case for a life-cycle lens towards building systems that are in line with current understanding of the earth’s finite resources. We do so by presenting an illustrative case study of what such critical alternatives might look like, by examining the Fairphone movement. We contribute to a deeper understanding of how social value laden enterprises along with open technological design can shape sustainable relationships between our environment and us.

Related paper presented at ICT4S:

Tessy Cerratto Pargman I am an associate professor of Human-Computer Interaction (HCI) at Stockholm University (SU) in Sweden since February 2003. My research belongs to the research field of human-computer interaction (HCI) and Technology Enhanced Learning (TEL). I am interested in the relationship between writing, meaning and technology from socio-cultural and critical perspectives of literacy and tool use. I work with a particular focus on design, adoption and use of technologies for participatory and collaborative purposes. I have after my sabbatical at UCI developed a special interest in issues pertaining to information technology and sustainability in HCI. I lead the research group on Critical Computing (CRITIC) and since january 2016 I am head of Interaction Design and Learning (IDEAL) research unit at the Dept. of Computer and Systems Sciences at Stockholm University.

Somya Joshi is a research scientist with expertise in the field of Human Computer Interaction when applied to Social Innovation & Sustainability. Her specialisation falls within the applied context of technological innovation, particularly in how it translates into transparency in governance, environmental conservation and health services within the developing world. She has experience working with a range of partners from academia, industry, NGOs, as well as international development organisations, towards the common goal of facilitating inclusive development. Currently, Somya is a Senior Lecturer and Research Fellow at eGovernance-Lab, within DSV (Department of Computer & Systems Science) at Stockholm University. She is responsible for course development and teaching on two Masters programs - namely: ICT4D, as well Open Governance & e-Democracy. In addition to this, she is teaching an Undergraduate course on Participatory Design and HCI - with a specific focus on Sustainability. Somya is at present project managing and researching within pan-European projects that aim to bring together the political-ecology of participation and sustainability within the same discourse.

Augmenting Elasticity Controllers for Improved Accuracy
Speakers: Navaneeth Rameshan
Thursday, July 14, 2016 - 14:00
Location: C6-E106

I'll be presenting our paper titled " Augmenting Elasticity Controllers for Improved Accuracy ", which is due to be presented at ICAC 2016. Abstract: Elastic resource provisioning is used to guarantee service level objectives (SLO) at reduced cost in a Cloud platform. However, performance interference in the hosting platform introduces uncertainty in the performance guarantees of provisioned services. Existing elasticity controllers are either unaware of this interference or over-provision resources to meet the SLO. In this paper, we show that assuming predictable performance of VMs in a multi-tenant environment to scale, will result in long periods of SLO violations. We augment the elasticity controller to be aware of interference and improve the convergence time of scaling without over provisioning. We perform experiments with Memcached and compare our solution against a baseline elasticity controller that is unaware of performance interference. Our results show that augmentation can reduce SLO violations by 65% or more and also save provisioning costs compared to an interference oblivious controller.

Hubbub-Scale: Towards Reliable Elastic Scaling under Multi-Tenancy
Speakers: Navaneeth Rameshan
Friday, May 6, 2016 - 15:30
Location: Updated Location: C6-E106

In this talk, I'll present our work on achieving reliable elastic scaling in multi-tenant environments. This paper is accepted for publication in CCGrid 2016 and is a rehearsal talk for the conference. Looking forward to your comments and feedback.

Elastic resource provisioning is used to guarantee service level objective (SLO) with reduced cost in a Cloud platform.
However, performance interference in the hosting platform introduces uncertainty in the performance guarantees of provisioned services.
Existing elasticity controllers are either unaware of this interference or over-provision resources to meet the SLO. In this paper, we show that assuming predictable performance of VMs to build an elasticity controller will fail if interference is not modelled. We identify and control the different sources of unpredictability and build Hubbub-Scale; an elasticity controller that is reliable in the presence of performance interference. Our evaluation with Redis and Memcached show that Hubbub-Scale efficiently conforms to the SLO requirements under scenarios where standard modelling approaches fail.

The Innovation Journey of Wi-Fi – The Road to Global Success
Speakers: Dr. Ir. Wolter Lemstra – TUDelft /Aalborg University - IBEI - UPF
Thursday, February 11, 2016 - 19:00
Location: moved to FIB B6 building Sala d’Actes.


Wi-Fi has become the preferred means for connecting to the internet - at home, in the office, universities, hotels and at airports. Increasingly, Wi-Fi also provides internet access for remote communities where it is deployed by volunteers in community-based networks, by operators in 'hotspots' and by municipalities in 'hotzones'. This presentation traces the global success of Wi-Fi to the landmark change in radio spectrum policy by the US FCC in 1985, the initiative by NCR Corporation to start development of Wireless-LANs and the drive for an open standard IEEE 802.11, released in 1997. It also singles out and explains the significance of the initiative by Steve Jobs at Apple to include Wireless-LAN in the iBook, which moved the product from the early adopters to the mass market. The presentation draws on the co-edited and co-authored book published by Cambridge University Press in 2011. It provides first-hand accounts by industry practitioners and concludes with reflections and implications for government policy and firm strategy.
  • First-hand industry perspectives link the practice of innovation to the theory of innovation
  • Shows how successful firm strategy relies on linking innovation to product introduction
  • Provides important advice for practitioners and policymakers about designing and applying successful standardisation strategies

About Wolter Lemstra

Dr. Ir. Wolter Lemstra is the 2016 Research Fellow at Catédra Telefónica, IBEI. He is also a Senior Research Fellow of the Section Economics of Infrastructures at the Department Technology, Policy & Management of the Delft University of Technology (TUDelft), The Netherlands, and Visiting Senior Research Fellow at Aalborg University – Copenhagen Center for Communication, Media and Information Technologies, Denmark. He thereby links his academic interests to 25 years of experience in the telecom sector. Most recently he was Vice-President at Lucent Technologies, responsible for marketing and business development in the EMEA region. In 1978 Wolter received his ‘Ingenieurs’-degree Cum Laude at the Faculty of Electrical Engineering of the TUDelft, with telecommunications as specialization. In 2006 he successfully defended his PhD dissertation exploring and explaining the impact of the Telecom/Internet bubble on the development path of the telecommunication sector. His current research is focussed on telecommunication sector governance, industry structure developments, firm strategic behaviour and innovation trajectories.

Detection of social positions in multi-relational social networks
Speakers: Davide Vega, PhD student
Thursday, May 21, 2015 - 15:30
Location: C6-E101

(The presentation will take place at room C6-E101 for availability reasons)
Work to be presented: XXXV Sunbelt Conference of the International Network for Social Network Analysis (INSNA) June 23 – June 28, 2015
Davide Vega, Matteo Magnani, Roc Meseguer, Felix Freitag


The detection of social positions and roles is a key task in the structural analysis of complex social systems. The continuous growth of social and media content has provided richer datasets that have been used to improve structural analysis methods, but have also highlighted the need to revise existing methods to take advantage of the additional information that can be found in the data, e.g., the presence of multiple types of connections between users. In this work we introduce a novel framework to detect position patterns in multi-relational graphs. Our framework complements traditional blockmodeling using extended node-based and distance-based metrics, enabling the discovery of positions that cannot be captured by existing methods. Thanks to these extended metrics our approach can be used to detect roles in multi-relational social networks.

26 weeks in Uppsala
Speakers: Davide Vega, Details: A talk by Davide about his stay at Uppsala University
Thursday, May 7, 2015 - 15:30
Location: C6-220

First talk: 26 weeks in Uppsala. Fika, Nature, Snow... BBQ! How these concepts are related? They could describe any Scandinavian country, but for me they will be always linked to Uppsala (Sweden), a University-city where I spent 26 weeks as part of my PhD. The talk intends to describe my experience in both, the university and the city. I will describe the Swedish university model and how it is related with the research and academic expectations there. It will be a good opportunity to share our experiences (as PhD's) in different institutions (you are welcome to share yours too!). As always, comparisons are a good tool for reflection and I think the talk could open some interesting discussion about our own institution and, more particularly, our research group.

Discussion about EMJD-DC event
Speakers: Everyone
Thursday, April 30, 2015 - 15:30
Location: C6-220

This meeting is more related to EMJD-DC doctorate students and tutors, but everyone is welcome. The idea is to discuss about the organization (timetables, logistics) of the upcoming EMJD-DC summer event. It would be nice if participants come prepared with some proposals based on what they expect from the event. Sorry for the late notice.

ICT Deployments for Disaster Relief
Speakers: Bob Marsh, Vice President Engineering and Co-Founder of Inveneo
Thursday, March 19, 2015 - 18:00
Location: C6-E106

(Please note that this week's meeting is at 18:00)


Inveneo has assisted relief and healthcare NGOs in the USA, Haiti, Philippines and W.Africa. Currently it has several its own and partner staff working on the ground in Sierra Leone and Liberia to bring broadband data access to organizations responding to the Ebola crisis.

Speaker Bio

Bob manages ICT projects from design to completion with more than 35 years of technical expertise. One of the early members of the fabled Homebrew Computer Club in Silicon Valley, Bob co-designed in 1975 one of the earliest personal computers, the Processor Technology Sol-20. Bob recently coordinated low-power rural computing projects in Botswana and Malawi as well as multi-stakeholder efforts to bring Internet service to over 100 youth centers and schools in underserved communities in the West Bank of Palestine.

Sneak preview of the presentation (discussion is going to follow)

Disaster Relief

Research Devices as a Service for Community Networks (updated abstract)
Speakers: Nuno Apolonia and Roshan Sedar, Details: An ongoing work from Nuno and Roshan, planned for submission to FiCloud 2015
Thursday, February 26, 2015 - 15:30
Location: C6-220

The Community-lab testbed introduces nodes at the edges of the Community network in order to give an environment where Community network members can easily deploy experiments on the nodes. However, there are limitations with the number of physical nodes that the Community-lab has deployed. Therefore, we propose that we can extend this number of testbeds in a virtualized way, without the need of adding new physical nodes to the network. Also, it would seem to be a good addition to have as a new automated service for community members in the Operating System so that members can deploy their own nodes with ease. Furthermore, we postulate two solutions, using virtualization, by using a virtual machine (QEmu emulation); or by using linux containers (LXC containers). Both solutions can have their advantages and disadvantages, and work within different environments. We are currently in the testing phase of our solutions, in order to gather an evaluation for a paper that we are going to submit in the coming weeks. Therefore, we appreciate any feedback on the way we deploy our solutions and also for the measurements needed to have a more complete evaluation of the community-lab virtualized nodes.

Internet-eXchange as a Common Pool resource
Speakers: Ramon Roca
Thursday, January 29, 2015 - 15:00
Location: C6-220

(Please note that this week's meeting is at 15:00)

Abstract is a telecommunications network, open, free and neutral, built through an interconnection agreement where each participant can connect extending the network and obtaining connectivity. Starting from few nodes and wireless links in 2003, is currently a network of more than 27000 operational nodes adopting also fiber technologies. A lot of aspects of this effort are worthy of studying but governance and sustainability are one of the key factors in a grassroots project of this size. Thus, in this talk we are going to review the Commons principles and the economic model followed, that allowed such a rapid growth. We are also going to see how is now planing to take the Commons principles to the next level, investigating economical and technological models to create a Commons model for the Internet-eXchanges.
Proposed Quick Reading
Material for the Governing of the Commons Network and its economic sustainability
How the ‘Net works: an introduction to peering and transit
Proposed More in Depth Reading : Resources to make strategic peering decisions
A primer on internet exchange points for policymakers and non-engineers

Speaker Bio

Ramon Roca is one of the founders and the President of Fundació Privada per a la Xarxa Oberta, Lliure i Neutral (The Foundation for the Open, Free and Neutral Network He has always been involved in IT social projects. In 2003 he had set up the first link of what few months later became the community network. That wireless link was his proposal to overcome the lack of ISPs Internet supply in his village located in the rural area in the countryside of Catalonia. Immediately after, he started promoting his solution among his neighbours and started enhancing the Free Networks' model. Nowadays he is repeating that process with optical fibre, deploying it according to what he has called the FFTF model, i.e. Fibre From The Farm, a wordplay to stress that the Fibre deployment is made by active common people, From The Farm, instead of by the telcos, To To The Home. This model, called as “Bottom-up Broadband initiative” by himself, was one out of eight selected ideas of the The Digital Agenda Stakeholder Day on 25 October 2010. His professional career has always been related to international IT companies.

Energy-aware Routing in the Internet of Things using Stackelberg Games
Speakers: Prof. Anastasios A. Economides
Thursday, December 18, 2014 - 15:30
Location: C6-220


In the Internet of Things various traffic streams generated by sensors will trade with intermediate relay nodes to forward their traffic to the destination. Since, these relay nodes receive compensation for forwarding the traffic, they will compete among themselves for doing this. This talk will first present an introduction to the Internet of Things and to the Routing problem. Then it will formulate and solve the problem as a Stackelberg game. Finally, it will present simulation results for various scenarios, and discuss open research issues.

Speaker Bio

Prof. Anastasios A. Economides is Full Professor on Computer Networks and Telematic Applications at the University of Macedonia, Thessaloniki, Greece. He received the Dipl.Eng. degree in electrical engineering from Aristotle University of Thessaloniki, in 1984. Holding a Fulbright and a Greek State Fellowship, he received the M.Sc. and the Ph.D. degrees in computer engineering from the University of Southern California, Los Angeles, in 1987 and 1990, respectively. The title of his Ph.D. thesis is: "A unified game-theoretic methodology for the joint load sharing, routing and congestion control problem". At graduation, he received the Outstanding Academic Achievement Award from the University of Southern California.
He is the director of CONTA (COmputer Networks and Telematic Applications) Laboratory. His research interests include networking protocols, competition & techno-economics, educational technology and smart services. He has published over 200 peer-reviewed papers.
He has been the plenary speaker in International Conferences, on the editorial board of several International Journals, and on the program committee of many International Conferences. He is an IEEE Senior member. Finally, he has been the principal investigator of 10 funded projects and participated in 25 funded projects.

Trans-Social Networks for Distributed Processing
Speakers: Nuno Apolonia, PhD candidate at UPC (new EMJD-DC student)
Thursday, December 4, 2014 - 15:30
Location: C6-220

Abstract: A natural succeeding process for the Internet was to create Social Networks (e.g. Facebook, among others), where anyone in the World can share their experiences, knowledge and information, using personal computers or mobile devices. In fact, Social Networks can be regarded as enabling information sharing in a peer-to-peer fashion. Given the enormous number of users, sharing could also be applied to the untapped potential of computing resources in users’ computers. By mining the user friendship graphs, we can perform people (and resource) discovery for distributed computing. Actually, employing Social Networks for distributed processing can have significant impact in global distributed computing, by letting users willingly share their idle computing resources publicly with other trusted users, or groups; this sharing extends to activities and causes that users naturally tend to adhere to. We describe the design, development and resulting evaluation of a web-enabled platform, called Trans-SocialDP: Trans-Social Networks for Distributed Processing. This platform can leverage Social Networks to perform resource discovery, mining friendship relationships for computing resources, and giving the possibility of resource (not only information) sharing among users, enabling cycle-sharing (such as in SETI@home) over these networks.

Paper presented at: IFIP'12 Proceedings of the 11th international IFIP TC 6 conference on Networking
Paper available here:

Stay-Away, protecting sensitive applications from performance interference
Speakers: Navaneeth Rameshan, PhD candidate at UPC,KTH
Thursday, November 20, 2014 - 16:00
Location: C6-220

To be presented in Middleware'14.

Title: Stay-Away, protecting sensitive applications from performance interference(30 minutes)

Abstract: While co-locating virtual machines improves utilization in resource shared environments, the resulting performance interference between VMs is difficult to model or predict. QoS sensitive applications can suffer from resource co-location with other less short-term resource sensitive or batch applications. The common practice of overprovisioning resources helps to avoid performance interference and guarantee QoS but leads to low machine utilization. Recent work that relies on static approaches suffer from practical limitations due to assumptions such as a priori knowledge of application behaviour and workload.

To address these limitations, we present Stay-Away, a generic and adaptive mechanism to mitigate the detrimental effects of performance interference on sensitive applications when co-located with batch applications. Our mechanism complements the allocation decisions of resource schedulers by continuously learning the favourable and unfavourable states of co-execution and mapping them to a state-space representation. Trajectories in this representation are used to predict and prevent any transition towards interference of sensitive applications by proactively throttling the execution of batch applications. The representation also doubles as a template to prevent violations in the future execution of the repeatable sensitive application when co-located with other batch applications. Experimental results with realistic applications show that it is possible to guarantee a high level of QoS for latency sensitive applications while also improving machine utilization.

Monitoring System for Community-Lab
Speakers: Navaneeth Rameshan, PhD candidate at UPC,KTH
Thursday, November 20, 2014 - 15:30
Location: C6-220

Title: Monitoring System for Community-Lab(30 minutes)

Abstract: In this session we will talk about the monitoring system for Community-Lab, its various capabilities, current limitations and future work. The metrics monitored include OS-provided resource consumption metrics, synthesized metrics such as open/closed ports and connectivity information. It also provides a view of the network topology and the general network health between the nodes. The design of the monitoring system ensures that no information is lost during network partitions, provides a complete historic access and supports aggregation of data at different granularities. The short talk will particularly focus on the different features of the monitoring system and will provide a short guide on the capabilities that can be leveraged by researchers to choose nodes before deploying a slice. Also people are encouraged to provide any suggestions for requirements or features they deem beneficial for researchers/admins. More information on the monitoring system can be found on the wiki.

Ongoing work and CONFINE review
Speakers: all
Thursday, November 6, 2014 - 15:30
Location: C6-220
Market-Oriented Cloud Computing and Big Data Applications
Speakers: Prof. Rajkumar Buyya
Thursday, July 10, 2014 - 11:00
Location: C6-E101

Prof. Rajkumar Buyya
Future Fellow, Australian Research Council (ARC),
Director, Cloud Computing and Distributed Systems (CLOUDS) Lab,
The University of Melbourne, Australia
CEO, Manjrasoft Pvt Ltd, Melbourne, Australia


Computing is being transformed to a model consisting of services that are commoditised and delivered in a manner similar to utilities such as water, electricity, gas, and telephony. In such a model, users access services based on their requirements without regard to where the services are hosted. Several computing paradigms have promised to deliver this utility computing vision. Cloud computing has emerged as one of the buzzwords in the IT industry and turned the vision of "computing utilities" into a reality. Several IT vendors have started offering computation, storage, and application hosting services, and provide coverage in several continents, supporting Service-Level Agreements (SLA) backed performance and uptime promises for their services. Clouds deliver infrastructure, platform, and software (application) as services, which are made available as subscription-based services in a pay-as-you-go model to consumers. The price that Cloud Service Providers charge can vary with time and the quality of service (QoS) expectations of consumers.
This seminar/keynote presentation will cover (a) 21st century vision of computing and identifies various IT paradigms promising to deliver the vision of computing utilities; (b) opportunities and challenges for utility and market-oriented Cloud computing, (c) innovative architecture for creating market-oriented and elastic Clouds by harnessing virtualisation technologies; (d) Aneka, a Cloud Application Platform, for rapid development of Cloud/Big Data applications and their deployment on private/public Clouds with resource provisioning driven by SLAs; (e) experimental results on deploying Cloud and Big Data applications in engineering, gaming, and health care domains (integrating sensors networks, mobile devices), ISRO satellite image processing on elastic Clouds, and (f) directions for delivering our 21st century vision along with pathways for future research.

Speaker Bio:

Dr. Rajkumar Buyya is Professor of Computer Science and Software Engineering, Future Fellow of the Australian Research Council, and Director of the Cloud Computing and Distributed Systems (CLOUDS) Laboratory at the University of Melbourne, Australia. He is also serving as the founding CEO of Manjrasoft, a spin-off company of the University, commercializing its innovations in Cloud Computing. He has authored over 450 publications and four text books including "Mastering Cloud Computing" published by McGraw Hill and Elsevier/Morgan Kaufmann, 2013 for Indian and international markets respectively. He also edited several books including "Cloud Computing: Principles and Paradigms" (Wiley Press, USA, Feb 2011). He is one of the highly cited authors in computer science and software engineering worldwide (h-index=81, g-index=164, 31600+ citations). Microsoft Academic Search Index ranked Dr. Buyya as the world's top author in distributed and parallel computing between 2007 and 2012. "A Scientometric Analysis of Cloud Computing Literature" by German scientists reported that Dr. Buyya is not only the world's most influential researcher, but also the most productive one in the area of cloud computing.
Software technologies for Grid and Cloud computing developed under Dr. Buyya's leadership have gained rapid acceptance and are in use at several academic institutions and commercial enterprises in 40 countries around the world. Dr. Buyya has led the establishment and development of key community activities, including serving as foundation Chair of the IEEE Technical Committee on Scalable Computing and five IEEE/ACM conferences. These contributions and international research leadership of Dr. Buyya are recognized through the award of "2009 IEEE TCSC Medal for Excellence in Scalable Computing". Manjrasoft's Aneka Cloud technology developed under his leadership has received "2010 Asia Pacific Frost & Sullivan New Product Innovation Award" and "2011 Telstra Innovation Challenge, People's Choice Award". He is currently serving as the foundation Editor-in-Chief (EiC) of IEEE Transactions on Cloud Computing. For further information on Dr. Buyya, please visit his cyberhome:

APC: Association for Progressive Communications
Speakers: Leandro
Thursday, May 22, 2014 - 12:00
Location: C6-220

A talk explaining the collaboration between our research group and Pangea as part of APC.
On June 1-9 several activities organised by APC will take place in the campus (Leandro is co-org). Some of the activities are:

  • June 1: Access Denied! An event about socio-tech discussion on DDOS and other Internet attacks to human rights and civil rights
  • 2-3 June: Internet Rights are Human Rights Training Workshop
  • 3 June: Welcome and New member orientation APC Executive Board meeting
  • 4-5 June: Take Back the Net! Event
  • 6 June: Share and Remix: Member collaboration and exchange

Semantic Technologies to support Cloud Applications' Portability and Interoperability on Multiple
Speakers: Beniamino Di Martino, PhD - Full Professor mOSAIC EU-ICT Project Coordinator - vice-Director Dipartimento di Ingegneria Industriale e dell'Informazione, Seconda Universita' di Napoli
Thursday, April 24, 2014 - 12:00
Location: C6-220

Cloud vendor lock-in and interoperability gaps arise (among many reasons) when semantics of resources and services, and of Application Programming Interfaces is not shared. Standards and techniques borrowed from SOA and Semantic Web Services areas might help in gaining shared, machine readable description of Cloud offerings (resources, Services at Platform and Application level, and their API groundings), thus allowing automatic discovery, matchmaking, and thus supporting selection, brokering, interoperability end even composition of Cloud Services among multiple Clouds. This series of two lectures starts with an introduction to Semantic Web and Semantic Web Services technologies, languages and tools. Then an overview of applications of semantic technologies is provided, in particular to discovery and management of Web and Cloud Services, APIs and resources. Finally, the outcomes of the mOSAIC EU funded project are presented: a Cloud Ontology, a Semantic Engine, and a Dynamic Semantic Discovery System. The second lecture consists of practical laboratory exercises and hands-on on Semantic tools for Ontology building and Semantic Web Services annotations. Expected results: Participating students will know about basic and advanced techniques for Semantic processing, Semantic Web Services, Cloud Computing and Cloud Portability / Interoperability issues. In addition, the visibility of the exchange program between the two Universities will hopefully be raised by this lecturing activity, and this might lead to further student exchanges. Day 1: Tuesday 12-14 (as part of the CLC-MIRI course) A5-106 Day 2: Thurdsay 12-13 (for the research group) C6-220 Day 3: Friday 12-14 (as part of the CLC-MIRI course) A5-106

Service discovery using a hypercube in PlanetLab
Speakers: Antonia Gallardo
Thursday, April 3, 2014 - 12:00
Location: C6-220

Dear all,

This is a first reminder that we are going to have a research meeting next Thursday 3rd at Campus Nord, Room C6-E220 at 12.00 am. Antonia will give us a talk about some interesting results from hers latest work, very related with her thesis.
Title: Service discovery using a hypercube in PlanetLab
Keywords: Fault-tolerant, Grid discovery service, Hypercube, PlanetLab
Nowadays P2P solutions for large-scale distributed systems as Grid computing are the focus of multiple research endeavors. These solutions require service discovery in order to allocate services     efficiently. Even though many service discovery methods have been proposed, there have not been enough studies that focus on fault-tolerant search engines. In this work, a fault-tolerant service discovery solution for large-scale distributed systems is proposed and it is evaluated using PlanetLab. In the experiments performed, the failure rate was high, even in a supported and monitored network as PlanetLab. Therefore, it is necessary to address the phenomenon of failure variable, using adaptive protocols for delivering a satisfactory experience to user. The proposed search algorithm allows inter-domain service discovery with any number of nodes. The service discovery solution has been evaluated using a set of 150 nodes in PlanetLab.  The nodes are interconnected by using an overlay network with an incomplete hypercube topology. At the moment of a service request, the algorithm adapts to failures that inevitably occur in any large distributed system.

Energy efficient economic model for community clouds: vision and challenges
Speakers: Leila, Leandro
Thursday, March 6, 2014 - 12:00
Location: C6-220

Energy consumption in IT infrastructure is becoming a critical issue nowadays. Looking forward, energy is going to be dear. The energy cost is going to exceed the infrastructure and maintenance cost; thus, as computer scientists, we should welcome the energy era by designing energy efficient architecture, resource management, etc.

In this talk we will speculate the energy consumption of different cloud architectures to find out about the energy efficiency of Community Cloud Computing(C3) architecture. Then we will discuss the possible energy- credit economic modeling and scheduling methods and their challenges; we will conclude with a case study of providing "Energy as a Service" (EaaS) on community clouds.

After the talk, Leandro and me are going to show you a couple of "good" examples based about how to disseminate your knowledge and interests on Internet providing open data and open tools. Maybe it could start an interesting discussion about it!

For people willing to attend remotely, we will share the presentation via Google Hangouts.

Experimental Evaluation of a Wireless Community Mesh Network
Speakers: Llorenç
Friday, January 17, 2014 - 12:00
Location: C6-220