Abstract: Based on our experience in designing, building and maintaining an information system for supporting a large scale electronic lottery, we present in this paper a unified approach to the design and implementation of electronic lotteries with the focus on pragmatic trust establishment. This approach follows closely the methodologies commonly employed in the development of general information systems. However, central to the proposed approach is the decomposition of a security critical system into layers containing basic trust components so as to facilitate the management of trust, first along the layers, and then as we move from layer to layer. We believe that such a structured approach, based on layers and trust components, can help designers of security critical applications produce demonstrably robust and verifiable systems that people will not hesitate to use.
Abstract: Large-scale sensor networks, monitoring an environment at close range with high spatial and temporal resolutions are expected to play an important role in various applications, e.g., assessing the ``health'' of machines; environmental, medical, food-safety, and habitat monitoring; inventory control, building automation, etc. Ensuring the security of these complex and yet resource-constrained systems has emerged as one of the most pressing challenges for researchers. In this paper (i) we present the major threats and some characteristic countermeasures, (ii) we propose a way to classify existing systems for intrusion detection in wireless sensor networks and (iii) we present a new approach for decentralized energy efficient intrusion detection that can be used to improve security from both external and internal adversaries.
Abstract: eVoting is considered to be one of the most challenging domains of modern eGovernment and one of the main vehicles for increasing eParticipation among citizens. One of the main obstacles for its wide adoptionis the reluctance of citizens to participate in electronic voting procedures. This reluctance can be partially attributed to the low penetration of technology among citizens. However, the main reason behind this reluctance is the lack of trust which stems from the belief of citizens that systems implementing an eVoting process will violate their privacy. The departure point of this approach is that the emergence of such a belief can be considerably facilitated by designing and building systems in a way that evidence about the system’s properties is produced during the design process. In this way, the designers can demonstrate the respect in privacy using this evidence that can be understood and checked by the specialist and the informed layman. These tools and models should provide sufficient evidence that the target system handles privacy concerns and requirements that can remove enough of the fears towards eVoting. This paper presents the efforts of the authors‘ organization, the Computer Technology Institute and Press “Diophantus” (CTI), towards the design and implementation of an eVoting system, called PNYKA, with demonstrable security properties. This system was based on a trust-centered engineering approach for building general security critical systems. The authors‘ approach is pragmatic rather than theoretical in that it sidesteps the controversy that besets the nature of trust in information systems and starts with a working definition of trust as people’s positive attitude towards a system that transparently and demonstrably performs its operations, respecting their privacy. The authors also discuss the social side of eVoting, i.e. how one can help boost its acceptance by large social groups targeting the whole population of the country. The authors view eVoting as an innovation that must be diffused to a population and then employ a theoretical model that studies diffusion of innovation in social network, delineating structural properties of the network that help diffuse the innovation fast. Furthermore, the authors explain how CTI’s current situation empowers CTI to realize its vision to implement a privacy preserving, discussion and public consultation forum in Greece. This forum will link, together, all Greek educational institutes in order to provide a privacy preserving discussion and opinion gathering tool useful in decision making within the Greek educational system.
Abstract: This work addresses networked embedded systems enabling the seam-
less interconnection of smart building automations to the Internet and
their abstractions as web services. In our approach, such abstractions are
used to primarily create a exible, holistic and scalable system and allow
external end-users to compose and run their own smart/green building
automation application services on top of this system.
Towards this direction, in this paper we present a smart building test-
bed consisting of several sensor motes and spanning across seven rooms.
Our test-bed's design and implementation simultaneously addresses sev-
eral corresponding system layers; from hardware interfaces, embedded
IPv6 networking and energy balancing routing algorithms to a RESTful
architecture and over the web development of sophisticated, smart, green
scenarios. In fact, we showcase how IPv6 embedded networking combined
with RESTful architectures make the creation of building automation ap-
plications as easy as creating any other Internet Web Service.
Abstract: A considerable part of recent research in smart cities and IoT has focused on achieving energy savings in buildings and supporting aspects related to sustainability. In this context, the educational community is one of the most important ones to consider, since school buildings constitute a large part of non-residential buildings, while also educating students on sustainability matters is an investment for the future. In this work, we discuss a methodology for achieving energy savings in schools based on the utilization of data produced by an IoT infrastructure installed inside school buildings and related educational scenarios. We present the steps comprising this methodology in detail, along with a set of tangible results achieved within the GAIA project. We also showcase how an IoT infrastructure can support activities in an educational setting and produce concrete outcomes, with typical levels of 20% energy savings.
Abstract: Raising awareness among young people on the
relevance of behaviour change for achieving energy savings is widely considered as a key approach towards long-term and costeffective energy efficiency policies. The GAIA Project aims to deliver a comprehensive solution for both increasing awareness on energy efficiency and achieving energy savings in school buildings. In this framework, we present a novel rule engine that, leveraging a resource-based graph model encoding relevant application domain knowledge, accesses IoT data for producing energy savings recommendations. The engine supports configurability, extensibility and ease-of-use requirements, to be easily applied and customized to different buildings. The paper introduces the main design and implementation details and presents a set of preliminary performance results.
Abstract: eVoting is a challenging approach for increasing eParticipation. However, lack of citizens¢ trust seems to be a main obstacle that hinders its successful realization. In this paper we propose a trust-centered engineering approach for building eVoting systems that people can trust, based on transparent design and implementation phases. The approach is based on three components: the decomposition of eVoting systems into “layers of trust” for reducing the complexity of managing trust issues in smaller manageable layers, the application of a risk analysis methodology able to identify and document security critical aspects of the eVoting system, and a cryptographically secure eVoting protocol. Our approach is pragmatic rather than theoretical in the sense that it sidesteps the controversy that besets the nature of trust in information systems and starts with a working definition of trust as people¢s positive attitude towards a system that performs its operations transparently.
Abstract: Energy consumption reserves a large portion of the budget for school buildings. At the same time, the students that use such facilities are the adults of the years to come and thus, should they embrace energy-aware behaviors, then sustainable results with respect to energy efficiency are anticipated. GAIA is a research project targeting this user domain, proposing a set of applications that a) aims at raising awareness, prompting action and fostering engagement in energy efficiency enhancement, and b) is adaptable to the needs of each facility/community. This application set relies on an IoT sensing infrastructure, as well as on the use of humans as sensors to create situational awareness.
Abstract: In this paper, a novel configuration is proposed for
the implementation of an almost all-optical switch architecture
called the scheduling switch, which when combined with appropriate
wait-for-reservation or tell-and-go connection and flow
control protocols provides lossless communication for traffic
that satisfies certain smoothness properties. An all-optical 2 2
exchange/bypass (E/B) switch based on the nonlinear operation
of a semiconductor optical amplifier (SOA) is considered as the
basic building block of the scheduling switch as opposed to active
SOA-based space switches that use injection current to switch
between ON and OFF states. The experimental demonstration of
the optically addressable 2 2 E/B, which is summarized for
10–Gb/s data packets as well as synchronous digital hierarchy
(SDH)/STM-64 data frames, ensures the feasibility of the proposed
configuration at high speeds, with low switching energy and low
losses during the scheduling process. In addition, it provides
reduction of the number of required components for the construction
of the scheduling switch, which is calculated to be 50% in the
number of active elements and 33% in the fiber length.
Abstract: The use of Augmented Reality (AR) technologies is currently being investigated in numerous and diverse application domains. In this work, we discuss the ways in which we are integrating AR into educational in-class activities for the GAIA project, aiming to enhance existing tools that target behavioral changes towards energy efficiency in schools. We combine real-time IoT data from a sensing infrastructure inside a fleet of school buildings with AR software running on tablets and smartphones, as companions to a set of educational lab activities aimed at promoting energy awareness in a STEM context. We also utilize this software as a means to ease access to IoT data and simplify device maintenance. We report on the design and current status of our implementation, describing functionality in the context of our target applications, while also relaying our experiences from the use of such technologies in this application domain.
Abstract: The use of maker community tools and IoT technologies inside classrooms is spreading to an ever-increasing number of education and science fields. GAIA is a European research project focused on achieving behavior change for sustainability and energy awareness in schools. In this work, we report on how a large IoT deployment in a number of educational buildings and real-world data from this infrastructure, are utilized to support a “maker” lab kit activity inside the classroom. We also provide some insights to the integration of these activities in the school curriculum, along with a discussion on feedback produced through a series of workshop activities in a number of schools in Greece. Moreover, we discuss the application of the lab kit framework towards implementing an interactive installation. We also report on how the lab kit is paired with a serious game and an augmented reality app for smartphones and tablets, supporting the in-class activities. Our initial evaluation results show a very positive first reaction by the school community.
Abstract: Raising awareness among young people and changing their behaviour and habits concerning energy usage is key to achieving sustained energy saving. Additionally, young people are very sensitive to environmental protection so raising awareness among children is much easier than with any other group of citizens. This work examines ways to create an innovative Information & Communication Technologies (ICT) ecosystem (including web-based, mobile, social and sensing elements) tailored specifically for school environments, taking into account both the users (faculty, staff, students, parents) and school buildings, thus motivating and supporting young citizens¢ behavioural change to achieve greater energy efficiency. A mixture of open-source IoT hardware and proprietary platforms on the infrastructure level, are currently being utilized for monitoring a fleet of 18 educational buildings across 3 countries, comprising over 700 IoT monitoring points. Hereon presented is the system¢s high-level architecture, as well as several aspects of its implementation, related to the application domain of educational building monitoring and energy efficiency. The system is developed based on open-source technologies and services in order to make it capable of providing open IT-infrastructure and support from different commercial hardware/sensor vendors as well as open-source solutions. The system presented can be used to develop and offer new app-based solutions that can be used either for educational purposes or for managing the energy efficiency of the building. The system is replicable and adaptable to settings that may be different than the scenarios envisioned here (e.g., targeting different climate zones), different IT infrastructures and can be easily extended to accommodate integration with other systems. The overall performance of the system is evaluated in real-world environment in terms of scalability, responsiveness and simplicity.
Abstract: We examine multi-player pervasive games that rely on the
use of ad-hoc mobile sensor networks. The unique feature in
such games is that players interact with each other and their
surrounding environment by using movement and presence
as a means of performing game-related actions, utilizing sen-
sor devices. We brie
y discuss the fundamental issues and
challenges related to these type of games and the scenar-
ios associated with them. We have also developed a frame-
work, called Fun in Numbers (FinN) that handles a number
of these issues, such as such as neighbors discovery, local-
ization, synchronization and delay-tolerant communication.
FinN is developed using Java and is based on a multilayer ar-
chitecture, which provides developers with a set of templates
and services for building and operating new games.
Abstract: In this work we present a platform-agnostic framework for intergrating heterogeneous Smart Objects in the Web of Things. Our framework, consists of 4 different hardware platforms, Arduino, SunSPOT, TelosB, iSense. These hardware platforms are the most representative ones, as used by the relevant research community. A first contribution of our work is a careful description of the necessary steps to make such a heterogeneous network interoperate and the implementation of a network stack, in the form of a software library, named mkSense, which enables their intercommunication. Moreover, we describe the design and implementation of software library which can be used for building “intelligent software” for the Web of Things.
Abstract: In this paper we present a protocol for Certified E-Mail that ensures temporal authentication. We first slightly modify a previously known three-message optimistic protocol in order to obtain a building block that meets some properties. We then extend this basic protocol enhancing it with the temporal authentication by adding a single message, improving the message complexity of known protocols. The fairness of the protocol is ensured by an off-line Trusted third party that joins the protocol only in case one of the players misbehaves. In order to guarantee temporal authentication we assume the existance of an on-line time stamping server.
Abstract: Clustering is an important research topic for wireless sensor
networks (WSNs). A large variety of approaches has been
presented focusing on di erent performance metrics. Even
though all of them have many practical applications, an ex-
tremely limited number of software implementations is avail-
able to the research community. Furthermore, these very few
techniques are implemented for speci c WSN systems or are
integrated in complex applications. Thus it is very difficult
to comparatively study their performance and almost impos-
sible to reuse them in future applications under a di erent
scope. In this work we study a large body of well estab-
lished algorithms. We identify their main building blocks
and propose a component-based architecture for developing
clustering algorithms that (a) promotes exchangeability of
algorithms thus enabling the fast prototyping of new ap-
proaches, (b) allows cross-layer implementations to realize
complex applications, (c) o ers a common platform to com-
paratively study the performance of di erent approaches,
(d) is hardware and OS independent. We implement 5 well
known algorithms and discuss how to implement 11 more.
We conduct an extended simulation study to demonstrate
the faithfulness of our implementations when compared to
the original implementations. Our simulations are at very
large scale thus also demonstrating the scalability of the
original algorithms beyond their original presentations. We
also conduct experiments to assess their practicality in real
WSNs. We demonstrate how the implemented clustering
algorithms can be combined with routing and group key es-
tablishment algorithms to construct WSN applications. Our
study clearly demonstrates the applicability of our approach
and the bene ts it o ers to both research & development
communities.
Abstract: In this work, we expanded the Arduino's
capabilities by adding an 802.15.4 wireless module, in order to
expose its functionality as a Web of Things node. The second
contribution of our work is a careful description of the necessary
steps to make a heterogeneous network interoperate and the
implementation of a network stack for the 4 most representative
hardware platforms, as used by the relevant research community
(Arduino, SunSPOT, TelosB, iSense), in the form of a software
library, named mkSense, which enables their
intercommunication. Moreover, we describe the design and
implementation of a software library which can be used for
building “intelligent software” for the Web of Things.
Abstract: Counting in general, and estimating the cardinality of (multi-) sets in particular, is highly desirable for a large variety of applications, representing a foundational block for the efficient deployment and access of emerging internet-scale information systems. Examples of such applications range from optimizing query access plans in internet-scale databases, to evaluating the significance (rank/score) of various data items in information retrieval applications. The key constraints that any acceptable solution must satisfy are: (i) efficiency: the number of nodes that need be contacted for counting purposes must be small in order to enjoy small latency and bandwidth requirements; (ii) scalability, seemingly contradicting the efficiency goal: arbitrarily large numbers of nodes nay need to add elements to a (multi-) set, which dictates the need for a highly distributed solution, avoiding server-based scalability, bottleneck, and availability problems; (iii) access and storage load balancing: counting and related overhead chores should be distributed fairly to the nodes of the network; (iv) accuracy: tunable, robust (in the presence of dynamics and failures) and highly accurate cardinality estimation; (v) simplicity and ease of integration: special, solution-specific indexing structures should be avoided. In this paper, first we contribute a highly-distributed, scalable, efficient, and accurate (multi-) set cardinality estimator. Subsequently, we show how to use our solution to build and maintain histograms, which have been a basic building block for query optimization for centralized databases, facilitating their porting into the realm of internet-scale data networks.
Abstract: In this work, we develop an IPv6 enabled smart building test-bed facility, by combining sensing and communication devices and functionalities. We address the Internet of Things paradigm by using diverse heterogeneous devices such as smartphones, sensor motes, NFC technology and traditional electrical devices, each one serving a specific role in the test-bed facility. Also, we extend a basic actuation component by making it self-aware, in terms of supported resources. Those enhancements allow us to enrich the test-bed’s capabilities in terms of M2M communication, portability and decentralization of the actuation process. Finally, we provide a simple smart room scenario for a tunable combination of energy eciency and comfort, which automatically adjusts the room’s light level based on ambient conditions and user preferences and demonstrate the feasibility of our system.
Abstract: We have designed and implemented a platform that enables monitoring and actuation in multiple buildings, that has been utilised in the context of a research project in Greece, focusing on public school buildings. The Green Mindset project has installed IoT devices in 12 Greek public schools to monitor energy consumption, along with indoor and outdoor environmental parameters. We present the architecture and actual deployment of our system, along with a first set of findings.
Abstract: The domain of smart cities is currently burgeoning, with a lot of potential for scientific and socio-economic innovation gradually being revealed. It is also becoming apparent that cross-discipline research will be instrumental in designing and building smarter cities, where IoT technology is becoming omnipresent. SmartSantander is an FP7 project that built a massive
city-scale IoT testbed aiming to provide both a tool for the research community and a functional system for the local government to implement operational city
services. In this work, we present key smart cities projects, main application domains and representative smart city frameworks that reflect the latest advances in the smart cities domain and our own experience through SmartSantander. The project has deployed 51.910 IoT endpoints, offering a massive infrastructure to the community, as well as functional system services and a number of end-user applications. Based on these aspects, we identify and
discuss a number of key scientific and technological challenges. We also present an overview of the developed system components and applications, and
discuss the ways that current smart city challenges were handled in the project.
Abstract: Counting items in a distributed system, and estimating the cardinality of multisets in particular,
is important for a large variety of applications and a fundamental building block for emerging Internet-scale information systems. Examples of such applications range from optimizing query access plans in peer-to-peer data sharing, to computing the significance (rank/score) of data items in distributed information retrieval. The general formal problem addressed in this article is computing the network-wide distinct number of items with some property (e.g., distinct files with file name
containing “spiderman”) where each node in the network holds an arbitrary subset, possibly overlapping the subsets of other nodes. The key requirements that a viable approach must satisfy are:
(1) scalability towards very large network size, (2) efficiency regarding messaging overhead, (3) load
balance of storage and access, (4) accuracy of the cardinality estimation, and (5) simplicity and easy
integration in applications. This article contributes the DHS (Distributed Hash Sketches) method
for this problem setting: a distributed, scalable, efficient, and accurate multiset cardinality estimator.
DHSis based on hash sketches for probabilistic counting, but distributes the bits of each counter
across network nodes in a judicious manner based on principles of Distributed Hash Tables, paying
careful attention to fast access and aggregation as well as update costs. The article discusses various
design choices, exhibiting tunable trade-offs between estimation accuracy, hop-count efficiency, and
load distribution fairness. We further contribute a full-fledged, publicly available, open-source implementation of all our methods, and a comprehensive experimental evaluation for various settings.
Abstract: Top-k query processing is a fundamental building block for efficient ranking in a large number of applications. Efficiency is a central issue, especially for distributed settings, when the data is spread across different nodes in a network. This paper introduces novel optimization methods for top-k aggregation queries in such distributed environments. The optimizations can be applied to all algorithms that fall into the frameworks of the prior TPUT and KLEE methods. The optimizations address three degrees of freedom: 1) hierarchically grouping input lists into top-k operator trees and optimizing the tree structure, 2) computing data-adaptive scan depths for different input sources, and 3) data-adaptive sampling of a small subset of input sources in scenarios with hundreds or thousands of query-relevant network nodes. All optimizations are based on a statistical cost model that utilizes local synopses, e.g., in the form of histograms, efficiently computed convolutions, and estimators based on order statistics. The paper presents comprehensive experiments, with three different real-life datasets and using the ns-2 network simulator for a packet-level simulation of a large Internet-style network.
Abstract: One of the most important applications of wireless sensor
networks is building monitoring and more speci cally, the
early detection of emergency events and the provision of
guidance for safe evacuation of the building. In this pa-
per, we describe a demo application that, in the event of a
re inside a monitored building, uses the information from
the deployed sensor network in order to nd the shortest
safest path away from the emergency and provides naviga-
tion guidance to the occupants (modelled by a mobile robot),
in order to safely evacuate the building. For this demo, we
developed our own ad-hoc robot-sensor interconnection us-
ing expansion connectors and programming in a low-level
language.
Abstract: Modern Wireless Sensor Networks offer an easy, lowcost
and reliable alternative to the back-end for monitoring
and controlling large geographical areas like Buildings
and Industries. We present the design and implementation details of an open and efficient Prototype System as a solution for low-cost BMS that comprises of heterogeneous, small-factor wireless devices. Placing that in the context of Internet of Things we come up with a solution that can cooperate with other systems installed on the same site to lower power consumption and costs as well as benefit humans that use its services in an transparent way. We evaluate and assess key aspects of the performance of our prototype. Our findings indicate specific approaches
to reduce the operation costs and allow the development of open applications.
Abstract: Few IoT systems monitoring energy consumption in buildings have focused on the educational community. IoT in the educational domain can jump-start a process of sustainability awareness and behavioral change towards energy savings, as well as provide tangible financial savings. We present a real-world multi-site IoT deployment, comprising 19 school buildings, aiming at enabling IoT-based energy awareness and sustainability lectures, promoting energy-saving behaviors supported by IoT data. We discuss scenarios where IoT-enabled applications are integrated into school life, providing an engaging and hands-on approach, based on real data, generating value in terms of educational and energy savings outcomes. We also present a set of first results, based on the analysis of school-building data, which highlight potential ways to identify irregularities and inefficiencies.
Abstract: Raising awareness among young people, and especially students, on the relevance of behavior change for achieving energy savings is increasingly being considered as a key enabler towards long-term and cost-effective energy efficiency policies. However, the way to successfully apply educational interventions focused on such targets inside schools is still an open question. In this paper, we present our approach for enabling IoT-based energy savings and sustainability awareness lectures and promoting data-driven energy-saving behaviors focused on a high school audience. We present our experiences toward the successful application of sets of educational tools and software over a real-world Internet of Things (IoT) deployment. We discuss the use of gamification and competition as a very effective end-user engagement mechanism for school audiences. We also present the design of an IoT-based hands-on lab activity, integrated within a high school computer science curriculum utilizing IoT devices and data produced inside the school building, along with the Node-RED platform. We describe the tools used, the organization of the educational activities and related goals. We report on the experience carried out in both directions in a high school in Italy and conclude by discussing the results in terms of achieved energy savings within an observation period.
Abstract: Several networking technologies targeting the IoT application space currently compete within the smart city domain, both in outdoor and indoor deployments. However, up till now, there is no clear winner, and results from real-world deployments have only recently started to surface. In this paper, we present a comparative study of 2 popular IoT networking technologies, LoRa and IEEE 802.15.4, within the context of a research-oriented IoT deployment inside school buildings in Europe, targeting energy efficiency in education. We evaluate the actual performance of these two technologies in real-world settings, presenting a comparative study on the effect of parameters like the built environment, network quality, or data rate. Our results indicate that both technologies have their advantages, and while in certain cases both are perfectly adequate, in our use case LoRa exhibits a more robust behavior. Moreover, LoRa¢s characteristics make it a very good choice for indoor IoT deployments such as in educational buildings, and especially in cases where there are low bandwidth requirements.
Abstract: Core optical networks using reconfigurable optical
switches and tunable lasers appear to be on the road towards
widespread deployment and could evolve to all-optical mesh
networks in the coming future. Considering the impact of physical
layer impairments in the planning and operation of all-optical
(and translucent) networks is the main focus of the DICONET
project. The impairment aware network planning and operation
tool (NPOT) is the main outcome of DICONET project, which
is explained in detail in this paper. The key building blocks of
the NPOT, consisting of network description repositories, the
physical layer performance evaluator, the impairment aware
routing and wavelength assignment engines, the component
placement modules, failure handling and the integration of
NPOT in the control plane are the main contributions of this
work. Besides, the experimental result of DICONET proposal for
centralized and distributed control plane integration schemes and
the performance of the failure handling in terms of restoration
time is presented in this work.
Abstract: ManyWSN algorithms and applications are based on knowledge
regarding the position of nodes inside the network area.
However, the solution of using GPS based modules in order
to perform localization in WSNs is a rather expensive solution
and in the case of indoor applications, such as smart
buildings, is also not applicable. Therefore, several techniques
have been studied in order to perform relative localization
in WSNs; that is, to compute the position of
a node inside the network area relatively to the position
of other nodes. Many such techniques are based on indicators
like the Radio Signal Strength Indicator (RSSI)
and the Link Quality Indicator (LQI). These techniques are
based on the assumption that there is strong correlation between
the Euclidian distance of the communicating motes
and these indicators. Therefore, high values of RSSI and
LQI should indicate physical proximity of two communicating
nodes. However, these indicators do not depend solely on
distance. Physical obstacles, ambient electromagnetic noise
and interferences from other wireless transmissions also affect
the quality of wireless communication in a stochastic
way. In this paper we propose, implement, experimentally
fine tune and evaluate a localization algorithm that exploits
the stochastic nature of interferences during wireless communications
in order to perform localization in WSNs. Our
algorithm is particularly designed for in-door localisation of
moving people in smart buildings. The localisation achieved
is fine-grained, i.e. the position of the target mote is successfully
computed with approximately one meter accuracy.
This fine-grained localisation can be used by smart Building
Management Systems in many applications such as room
adaptation to presence. In our scenario, our proposed algorithm is used by a smart room in order to localise the
position of people inside the room and adapt room illumination
accordingly.
Abstract: Building efficient internet-scale data management services is the main focus of this chapter. In particular, we aim to show how to leverage DHT technology and extend it with novel algorithms and architectures in order to (i) improve efficiency and reliability for traditional DHT (exact-match) queries, particularly exploiting the abundance of altruism witnessed in real-life P2P networks, (ii) speedup range queries for data stored on DHTs, and (iii) support efficiently and scalably the publish/subscribe paradigm over DHTs, which crucially depends on algorithms for supporting rich queries on string-attribute data.
Abstract: Green Awareness in Action (GAIA) is introducing game challenges to the school community, where real-world sensor data produced inside school buildings are used,
aiming to increase awareness and reduce energy consumption. An initial small-scale in-school evaluation trial of the games¢ deployment is reported here.
Abstract: Educational buildings constitute 17% of the non-residential building stock in the EU [1], while recent work shows that a focus on energy use in schools can potentially yield an array of rewards, in concert with educational excellence and a healthy learning environment [2].
Having these in mind, GAIA1, a Horizon2020 EC-funded project, is developing an IoT platform
that combines sensing, web-based and gamification elements, in order to address the
educational community. Its primary aim is to increase awareness about energy consumption
and sustainability, based on real sensor data produced by the school buildings where students and teachers live and work, while also lead towards behavior change in terms of energy efficiency.
Abstract: The Internet of Things is shaping up to be the ideal vehicle for introducing pervasive computing in our everyday lives, especially in the form of smart home and building management systems. However, although such technologies are gradually becoming more mainstream, there is still a lot of ground to be covered with respect to public buildings and specifically ones in the educational sector. We discuss here \Green Mindset", an action focusing on energy efficiency and
sustainability in Greek public schools. A large-scale sensor infrastructure has been deployed to 12 public school buildings across diverse settings. We report on the overall design and implementation of the system, as well as on some first results coming from the data produced. Our system provides a flexible and efficient basis for realizing a unified approach to monitoring energy consumption and environmental parameters,
that can be used both for building administration
and educational purposes.
Abstract: Human mobility monitoring and respective traces are important for understanding human behavior, respective patterns and associated context. Such data can be potentially used in business intelligence-oriented systems, for providing added value commercial services or insight to internal enterprise procedures. At the same time, smartphones are rapidly becoming an indispensable tool for our everyday life, while their advanced networking and computing capabilities are increasingly being used as enablers for new applications. We discuss here a system using a stable computing and networking infrastructure along with smartphone applications, based on commodity technologies, meant to be deployed rapidly and provide analytics almost in real-time for such aspects. We also discuss a related scenario in order to provide insight as to where our system could be used. We briefly present the deployment of our system in two settings, an office building and a research exhibition event, along with our experiences. Our findings show that it is feasible and efficient to deploy and operate our system relatively easy, producing meaningful data.
Abstract: Internet of Things technologies are considered the next big
step in Smart Building installations. Although such technologies have
been widely studied in simulation and experimental scenarios it is not so
obvious how problems of real world installations should be dealt with. In
this work we deploy IoT devices for sensing and control in a multi-office
space and employ technologies such as CoAP, RESTful interfaces and
Semantic Descriptions to integrate them with the Web. We report our
research goals, the challenges we faced, the decisions we made and the
experience gained from the design, deployment and operation of all the
hardware and software components that compose our system.
Abstract: We present here, Fun in Numbers, a framework for developing multiplayer pervasive games that rely on the use of ad hoc mobile sensor networks. The unique feature in such games is that players interact with each other and their surrounding environment by using movement and presence as a means of performing game-related actions, utilizing sensor devices. We present the fundamental issues and challenges related to these type of games and the scenarios associated with them is provided. Our framework is developed using Java and is based on a multilayer architecture, which provides developers with a set of templates and services for building and operating new games. Our framework handles a number of challenging fundamental and practical issues, such as synchronization, network congestion, delay-tolerant communication and neighbors discovery. We also present our platform and identify issues that arise in pervasive games which utilize sensor network nodes. The implemented games show how to use non-conventional user interface methods to breathe new life into familiar concepts, like the multiplayer games played out in open space.
Abstract: Understanding the graph structure of the Internet is a crucial step for building accurate
network models and designing efficient algorithms for Internet applications.Yet,obtaining this graph
structure can be a surprisingly difficult task,as edges cannot be explicitly queried.For instance,
empirical studies of the network of InternetProtocol (IP) addresses typically rely on indirect methods
like trace route to build what are approximately single-source,all-destinations,shortest-path trees.
These trees only sample a fraction of the network’s edges,and a paper by Lakhinaetal.[2003]found
empirically that there sulting sample is intrinsically biased.Further,in simulations,they observed that the degree distribution under trace route sampling exhibits a power law even when the underlying
degree distribution is Poisson.
Abstract: One oft-cited strategy towards sustainability is improving energy efficiency inside public buildings. In this context, the educational buildings sector presents a very interesting and important case for the monitoring and management of buildings, since it addresses both energy and educational issues. In this work, we present and discuss the hardware IoT infrastructure substrate that provides real-time monitoring in multiple school buildings. We believe that such a system needs to follow an open design approach: rely on hardware-agnostic components that communicate over well-defined open interfaces. We present in detail the design of our hardware components, while also providing insights to the overall system design and a first set of results on their operation. The presented hardware components are utilized as the core hardware devices for GAIA, an EU research project aimed at the educational community. As our system has been deployed and tested in several public school buildings in Greece, we also report on its validation.
Abstract: The content-based publish/subscribe (pub/sub) paradigm for system design is becoming increasingly popular, offering
unique benefits for a large number of data-intensive applications. Coupled with the peer-to-peer technology, it can serve as
a central building block for developing data-dissemination applications deployed over a large-scale network infrastructure.
A key open problem towards the creation of large-scale content-based pub/sub infrastructures relates to efficiently and accu-
rately matching subscriptions with substring predicates to incoming events. This work addresses this issue.
Abstract: The content-based publish/subscribe (pub/sub)paradigm for system design is becoming increasingly popular, offering unique benefits for a large number of data-intensive applications. Coupled with the peer-to-peer technology, it can serve as a central building block for such applications
deployed over a large-scale network infrastructure. A key problem toward the creation of large-scale contentbased pub/sub infrastructures relates to dealing efficiently with continuous queries (subscriptions) with rich predicates on string attributes; In particular, efficiently and accurately
matching substring queries to incoming events is an open problem. In this work we study this problem. We provide and analyze novel algorithms for processing subscriptions with substring predicates and events in a variety of environments. We provide experimental data demonstrating the
relative performance behavior of the proposed algorithms using as key metrics the network bandwidth requirements, number of messages, load balancing, as well as requirements for extra routing state (and related maintenance) and design flexibility.
Abstract: We consider the QoS-aware Multicommodity Flow problem,
a natural generalization of the weighted multicommodity flow problem
where the demands and commodity values are elastic to the Quality-of-
Service characteristics of the underlying network. The problem is fundamental
in transportation planning and also has important applications
beyond the transportation domain. We provide a FPTAS for the QoSaware
Multicommodity Flow problem by building upon a Lagrangian
relaxation method and a recent FPTAS for the non-additive shortest
path problem.
Abstract: Braess’s paradox states that removing a part of a network may im-
prove the players’ latency at equilibrium. In this work, we study the approxima-
bility of the best subnetwork problem for the class of random
G
n;p
instances
proven prone to Braess’s paradox by (Roughgarden and Valiant, RSA 2010) and
(Chung and Young, WINE 2010). Our main contribution is a polynomial-time
approximation-preserving reduction of the best subnetwork problem for such in-
stances to the corresponding problem in a simplified network where all neighbors
of
s
and
t
are directly connected by
0
latency edges. Building on this, we obtain
an approximation scheme that for any constant
" >
0
and with high probabil-
ity, computes a subnetwork and an
"
-Nash flow with maximum latency at most
(1+
"
)
L
+
"
, where
L
is the equilibrium latency of the best subnetwork. Our ap-
proximation scheme runs in polynomial time if the random network has average
degree
O
(poly(ln
n
))
and the traffic rate is
O
(poly(lnln
n
))
, and in quasipoly-
nomial time for average degrees up to
o
(
n
)
and traffic rates of
O
(poly(ln
n
))
.
Abstract: Buildings are among the largest consumers of electricity with a significant portion of this energy use is wasted in unoccupied areas or improperly installed devices.
Identifying such power leaks is hard especially in large office and enterprise buildings.
In this paper we present the design and implementation of a system that uses an underlying sensor network to provide accurate real time information about various characteristics like occupancy, lighting, temperature and power consumption at different levels of granularity.
All sensor devices require minimal installation and maintenance.
Using an experimental installation we evaluate a number of applications and services that achieve energy savings by applying different power conservation policies.
Furthermore we provide energy measurements to users and occupants to show how various choices and behaviors affect their personal energy savings.
Abstract: In wireless communication, the signal of a typical broadcast station is transmittes from a broadvast center p and reaches objects at a distance,say , r from it. In addition there is a radius ro, ro < r, such that the signal originating from the center p should be avoided. In other words, points within distance ro from the station compise a hazardous zone. We consider the following station layout problem: Cover a given planar region that includes a collection of buildings with a minimum number of astations so that every point in the region is within the reach of a station, while at the same time no interior point of any building is within the hazardous zone of a station. We give algorithms for computing such station layouts in both the one- and two - dimensional cases
Abstract: The content-based publish/subscribe (pub/sub)
paradigm for system design is becoming increasingly
popular, offering unique benefits for a large number of
data-intensive applications. Coupled with the peer-to-peer
technology, it can serve as a central building block for
such applications deployed over a large-scale network
infrastructure. A key problem toward the creation of
large-scale content-based pub/sub infrastructures relates to
dealing efficiently with continuous queries (subscriptions)
with rich predicates on string attributes; in this work we
study the problem of efficiently and accurately matching
substring queries to incoming events.
Abstract: Today¢s students are the citizens of tomorrow, and they should have the skills and tools to understand and respond to climate change. Green Awareness in Action (GAIA) has built an IoT infrastructure within 25 schools in Europe, in order to enable lectures that target sustainability and energy efficiency, based on data produced inside school buildings. The school community has reacted very positively to this approach and has reduced energy consumption as a consequence.
Abstract: A lot of activity is being devoted to studying issues related to energy consumption and efficiency in our buildings, and especially on public buildings. In this context, the educational public buildings should bean important part of the equation. At the same time, there is an evident need for open datasets, which should be publicly available for researchers to use. We have implemented a real-world multi-site Inter-net of Things (IoT) deployment, comprising 25 school buildings across Europe, primarily designed as a foundation for enabling IoT-based energy awareness and sustainability lectures and promoting data-driven energy-saving behaviors. In this work, we present some of the basic aspects to producing datasets from this deployment and discuss its potential uses. We also provide a brief discussion on data derived from a preliminary analysis of thermal comfort-related data produced from this infrastructure.
Abstract: The Greek School Network (GSN) is a closed nationwide
educational network that offers advanced telematic and
networking services to all primary/secondary education schools
and administration offices in Greece. The primary objective of
GSN is the provisioning of a network infrastructure for the interconnection
of school PC laboratories so that modern educational
methods and pedagogical models can be applied to the school
community. GSN has scaled in size, has reached maturity, and
is currently delivering a wide range of network and telematic
services to its users. The emerging power of open-source software
provides a sound technological basis for building cutting-edge
services, capable of meeting internal administrative and monitoring
needs, and modern pedagogical requirements for tools and
services. The current paper presents an overview of GSN and an
evaluation of its services based on the opinions of its users, and on
service utilization and traffic measurement statistics. The paper
reaches the conclusion that open-source solutions provide a sound
technological platform that can cover, to a great extent, the needs
for advanced educational services of the school community.
Abstract: In this paper, we discuss the integration of Wireless
Sensor Networks (WSN) and smart objects with the Web. We present a set of research challenges which we believe are the most important ones rising from this integration and propose a prototype system, Uberdust, which addresses such challenges. Uberdust is a brokerage web service for connecting smart objects to the Internet of Things, providing storage, sharing and discovery of real-time and historical data from smart objects, devices & building installations around the world via the Web. Our system provides high-level language-independent APIs so IoT application developers may choose their favorite programming or scripting languages.
Abstract: Digital optical logic circuits capable of performing bit-wise signal processing are critical building blocks for the realization of future high-speed packet-switched networks. In this paper, we present recent advances in all-optical processing circuits and examine the potential of their integration into a system environment. On this concept, we demonstrate serial all-optical Boolean AND/XOR logic at 20 Gb/s and a novel all-optical packet clock recovery circuit, with low capturing time, suitable for burst-mode traffic. The circuits use the semiconductor-based ultrafast nonlinear interferometer (UNI) as the nonlinear switching element. We also present the integration of these circuits in a more complex unit that performs header and payload separation from short synchronous data packets at 10 Gb/s. Finally, we discuss a method to realize a novel packet scheduling switch architecture, which guarantees lossless communication for specific traffic burstiness constraints, using these logic units.
Abstract: In this paper, we review recent advances in ultrafast optical time-domain technology with emphasis on the use in optical packet switching. In this respect, several key building blocks, including high-rate laser sources applicable to any time-division-multiplexing (TDM) application, optical logic circuits for bitwise processing, and clock-recovery circuits for timing synchronization with both synchronous and asynchronous data traffic, are described in detail. The circuits take advantage of the ultrafast nonlinear transfer function of semiconductor-based devices to operate successfully at rates beyond 10 Gb/s. We also demonstrate two more complex circuits-a header extraction unit and an exchange-bypass switch-operating at 10 Gb/s. These two units are key blocks for any general-purpose packet routing/switching application. Finally, we discuss the system perspective of all these modules and propose their possible incorporation in a packet switch architecture to provide low-level but high-speed functionalities. The goal is to perform as many operations as possible in the optical domain to increase node throughput and to alleviate the network from unwanted and expensive optical-electrical-optical conversions.
Abstract: The use of maker community tools and IoT technologies inside classrooms is spreading in an increasing number of education and science fields. GAIA is a European research project focused on achieving behavior change for sustainability and energy awareness in schools. In this work, we report on how a large IoT deployment in a number of educational buildings and real-world data from this infrastructure, are utilized to support a "maker" lab kit activity inside the classroom, together with a serious game. We also provide some insights to the integration of these activities in the school curriculum, along with a discussion on our feedback so far from a series of workshop activities in a number of schools. Our initial results show strong acceptance by the school community.
Abstract: The Internet of Things (IoT) and smart cities are two of the most popular directions the research community is pursuing very actively. But although we have made great progress in many fields, we are still trying to figure out how we can utilize our smart city and IoT infrastructures, in order to produce reliable, economically sustainable solutions that create public value, and even more so in the field of education.
GAIA1, a Horizon2020 EC-funded project, has developed an IoT infrastructure across school buildings in Europe. Its primary aim has been to raise awareness about energy consumption and sustainability, based on real-world sensor data produced inside the school buildings where students and teachers live and work. Today's students are the citizens of tomorrow, and they should have the skills to understand and respond to challenges like climate change. Currently, 25 educational building sites participate in GAIA, located in Sweden, Italy, and Greece. An IoT infrastructure [1] is installed in these buildings, monitoring in real-time their power consumption, as well as several indoor and outdoor environmental parameters.
Abstract: The utilization of IoT in the educational domain so far has trailed other more commercial application domains. In this chapter, we study a number of aspects that are
based on big data produced by a large-scale infrastructure deployed inside a fleet of educational buildings in Europe. We discuss how this infrastructure essentially enables a set of different applications, complemented by a detailed discussion regarding both performance aspects of the implementation of this IoT platform, as well as results that provide insights to its actual application in real life, both from an educational and business standpoint.
Abstract: There exists a great amount of algorithms for wireless sensor networks (WSNs) that have never been tried in practice. This is due to the fact that programming sensor nodes still happens on a very technical level. We remedy the situation by introducing our algorithm library Wiselib, which allows for simple implementations of algorithms. It can adopt to a large variety of hardware and software. This is achieved by employing advanced C++ techniques such as templates and inline functions, which allow to write generic code that is resolved and bound at compile time, resulting in virtually no memory or computation overhead at run time. The Wiselib runs on different host operating systems such as Contiki, iSense OS, and ScatterWeb. Furthermore, it runs on virtual nodes simulated by Shawn. The Wiselib provides an algorithm with data structures that suit the specific properties of the target platform. Algorithm code does not contain any platform-specific specializations, allowing a single implementation to run natively on heterogeneous networks. In this paper, we describe the building blocks of the Wiselib, analyze the overhead, and show how cryptographically secured routing algorithms can be implemented. We also report on results from experiments with real sensor node hardware.
