Ivana Podnar Zarko

Ivana Podnar Zarko
University of Zagreb · Faculty of Electrical Engineering and Computing (FER)

PhD

About

93
Publications
45,157
Reads
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1,893
Citations
Additional affiliations
September 2012 - present
University of Zagreb
Position
  • Professor (Associate)
February 2005 - August 2006
École Polytechnique Fédérale de Lausanne
Position
  • PostDoc Position
January 2000 - January 2001
TU Wien
Position
  • Research Associate

Publications

Publications (93)
Article
Mobile crowdsensing (MCS) is a human-driven Internet of Things (IoT) service empowering citizens to observe phenomena of individual, community, or even societal value by sharing sensor data about their environment while on the move. Typical MCS service implementations utilize cloud-based centralized architectures which consume a lot of computationa...
Article
Supply chain management enhanced by Internet of Things (IoT) solutions integrates special tags (e.g., RFID, NFC, QR-codes) with products to create Smart Tags, which, in addition to storing supplemental information about a product, are also used to track products during their lifecycle. However, a product consumer has to implicitly trust the Smart T...
Article
Full-text available
The success of the sustainable transformation of the energy sector, both in terms of planning and operation, relies on new entities, business models, and technologies. The shift from a relatively small number of centralized bulk producers and single direction energy flow to a decentralized multi-actor renewable system with a two-way flow of energy...
Preprint
Full-text available
A new node joining a blockchain network first synchronizes with the network to verify ledger state by downloading the entire ledger history. We present Aurora, a probabilistic algorithm that \textit{identifies honest nodes} for transient or persistent communication in the presence of malicious nodes in a blockchain network, or ceases operation if i...
Article
Full-text available
Light clients for distributed ledger networks can verify blockchain integrity by downloading and analyzing blockchain headers. They are designed to circumvent the high resource requirements, i.e., the large bandwidth and memory requirements that full nodes must meet, which are unsuitable for consumer-grade hardware and resource-constrained devices....
Article
Full-text available
Mobile crowdsensing (MCS) is a sensing paradigm that allows ordinary citizens to use mobile and wearable technologies and become active observers of their surroundings. MCS services generate a massive amount of data due to the vast number of devices engaging in MCS tasks, and the intrinsic mobility of users can quickly make information obsolete, re...
Conference Paper
Implementation of an efficient meter data management system presents a challenging task since it has to process and store a large number of incoming time-series data entries in almost real-time. A number of solutions for efficient processing and storage of big data streams are today available as open source or commercial software. However, the choi...
Article
Full-text available
Even though various commercial Smart City solutions are widely available on the market, we are still witnessing their rather limited adoption, where solutions are typically bound to specific verticals or remain in pilot stages. In this paper we argue that the lack of a Smart City regulatory framework is one of the major obstacles for a wider adopti...
Preprint
Full-text available
Nowadays, blockchain is becoming a synonym for distributed ledger technology. However, blockchain is only one of the specializations in the field and is currently well-covered in existing literature, but mostly from a cryptographic point of view. Besides blockchain technology, a new paradigm is gaining momentum: directed acyclic graphs. The contrib...
Conference Paper
Full-text available
While the current highly fragmented Internet of Things (IoT) ecosystem is characterized by an increasing number of platforms, their interoperability and collaboration is quite challenging to achieve, even more so due to numerous standardization initiatives. However, interoperability remains essential for future IoT deployments to facilitate the eme...
Conference Paper
The Internet of Things (IoT) is expanding and reaching the maturity level beyond initial deployments. An integrative and interoperable IoT platform proves to be a suitable execution environment for Smart City services because users simultaneously use multiple services, while an IoT platform enables cross-service data sharing. A large number of vari...
Chapter
Nowadays, air quality monitoring is identified as one of the key impacts in assessing the quality of life in urban areas. Traditional measuring procedures include expensive equipment in the fixed monitoring stations which is not suitable for urban areas because of the low spatio-temporal density of measurements. On the other hand, the technological...
Book
This book constitutes the thoroughly refereed post-conference proceedings of the second International Workshop on Interoperability and Open-Source Solutions for the Internet of Things, InterOSS-IoT 2016, held in Stuttgart, Germany, November 7, 2016. The 11 revised full papers presented were carefully reviewed and selected from 17 submissions during...
Article
The rapidly increasing interest that the Internet of Things (IoT) has received both in academia and industry over the past few years has already resulted in a huge number of IoT platforms which, however, typically are conceived as individual vertically integrated systems without supporting inter-platform collaboration and interaction. In this paper...
Article
Cloud of Things (CoT) is a novel concept driven by the synergy of the Internet of Things (IoT) and cloud computing paradigm. The CoT concept has expedited the development of smart services resulting in the proliferation of their real world deployments. However, new research challenges arise because of the transition of research-driven and proof-of-...
Conference Paper
Full-text available
The Internet of Things is evolving around a plethora of vertical platforms, each specifically suited to a given scenario and often adopting proprietary communications, device and resource control protocols. The emerging need for cross-domain IoT applications and services highlights the necessity of interoperability across IoT platforms for a unifie...
Article
Full-text available
The paper analyses and compares the different approaches to achieve semantic interoperability of the most influential IoT reference architectures, namely the Industrial Internet Reference Architecture, Reference Architecture Model Industrie 4.0, ISO/IEC Internet of Things Reference Architecture, the Internet of Things – Architecture (IoT-A) and one...
Article
Mobile Crowd Sensing (MCS) is a novel class of Internet of Things applications which exploits the inherent mobility of wearable sensors and mobile devices to observe phenomena of common interest, typically over large geographical areas (e.g. traffic conditions, air pollution, noise in urban areas). Since MCS applications generate large amounts of s...
Article
Mobile crowd sensing (MCS) is a novel class of mobile Internet of Things (IoT) applications for community sensing where sensors and mobile devices jointly collect and share data of interest to observe phenomena over a large geographic area. The inherent device mobility and high sensing frequency has the capacity to produce dense and rich spatiotemp...
Article
Machine learning algorithms are often used in content-based recommender systems since a recommendation task can naturally be reduced to a classification problem: A recommender needs to learn a classifier for a given user where learning examples are characteristics of items previously liked/bought/seen by the user. However, multi-valued and continuo...
Conference Paper
The ACM DEBS Grand Challenge 2015 focuses on real-time analytics over a high volume geospatial data stream composed of taxi trip reports from New York City. The goal of the challenge is to provide a solution which continuously identifies the most frequent routes (query 1) and most profitable areas (query 2) for taxis in New York City. The solution...
Conference Paper
Sensor technology and sensor networks have evolved so rapidly that they are now considered a core driver of the Internet of Things (IoT), however data analytics on IoT streams is still in its infancy. This paper introduces an approach to sensor data analytics by using the OpenIoTmiddleware; real time event processing and clustering algorithms have...
Article
A sliding window top-k (top-k/w) query monitors incoming data stream objects within a sliding window of size w to identify the k best-ranked objects with respect to a given scoring function over time. Processing of such queries is challenging because, even when an object is not a top-k/w object at the time when it enters the processing system, it m...
Article
Full-text available
Despite the proliferation of Internet-of-Things (IoT) platforms for building and deploying IoT applications in the cloud, there is still no easy way to integrate heterogeneous geographically and administratively dispersed sensors and IoT services in a semantically interoperable fashion. In this paper we provide an overview of the OpenIoT project, w...
Article
Full-text available
Given the prominence of IoT applications integrating mobile Internet-connected objects (ICOs), e.g., wearable sensors and mobile devices with built-in sensors, novel solutions are required to discover and collect data from mobile sensors producing data streams from varying locations, while taking into account sensor accuracy, energy-efficiency, and...
Article
We demonstrate an urban crowd sensing application for monitoring air quality by use of specially-designed wearable sensors and mobile phones. The application is built upon the OpenIoT platform1 with the goal to support context-aware and energy-efficient acquisition and filtering of sensor data in mobile environments while ensuring adequate sensing...
Book
This book constitutes the thoroughly refereed post-conference proceedings of the International Workshop on Interoperability and Open-Source Solutions for the Internet of Things, FP7 OpenIot Project, held in Conjunction with SoftCOM 2014, in Split, Croatia, in September 2014. The 11 revised full papers presented together with the extended abstracts...
Article
We are witnessing the rise of a novel class of wearable devices equipped with various sensing capabilities as well as further miniaturization of sensing components that are nowadays being integrated into mobile devices. The inherent mobility of such devices has the capacity to produce dense and rich spatiotemporal information about our environment...
Conference Paper
Full-text available
We demonstrate an urban crowd sensing application for monitoring air quality by use of specially-designed wearable sensors and mobile phones. The application is built upon the OpenIoT platform\footnote{The EU FP7 project OpenIoT is the winner of the Open Source Rookie of the Year 2013. For more information visit www.openiot.eu} with the goal to sup...
Conference Paper
Full-text available
With the advent of Smart Cities, public transport authorities are more and more interested in Intelligent Transport System (ITS) applications that allow to process a large amount of static and real time data in order to make public transport smarter. However, deploying such applications in a large scale distributed environment is challenging and re...
Conference Paper
Full-text available
We are witnessing the rise of a novel class of wearable devices equipped with various sensing capabilities as well as further miniaturization of sensing components that are nowadays being integrated into mobile devices. The inherent mobility of such devices has the capacity to produce dense and rich spatiotemporal information about our environment...
Conference Paper
Full-text available
Recent advances in the Internet of Things (IoT) domain for deploying IoT data systems within the cloud have generated Internet-connected silos of sensor technology which make the collection and processing of sensor-generated information more complex. A viable solution to this problem is the use of local sub-servers acting as collector's hubs betwee...
Article
Continuous processing of top-k queries over data streams is a promising technique for alleviating the information overload problem as it distinguishes relevant from irrelevant data stream objects with respect to a given scoring function over time. Thus it enables filtering of irrelevant data objects and delivery of top-k objects relevant to user in...
Conference Paper
In this paper we focus on mobile crowdsensing applications for community sensing where sensors and mobile devices jointly collect and share data of interest to observe and measure phenomena over a larger geographic area. Such applications, e.g., environmental monitoring or crowdsourced traffic monitoring, involve numerous individuals that on the on...
Conference Paper
In the context of communication services, presence is defined as the willingness and ability of a user to communicate across a set of devices with other users, and thus an up-to-date user presence status represents an essential prerequisite for real-time communications. Smartphones are a rich source of presence-related contex information, however;...
Conference Paper
Full-text available
Internet Protocol Television (IPTV) is an increasingly popular multimedia service which is used to deliver television, video, audio and other interactive content over proprietary IP-based networks. Video on Demand (VoD) is one of the most popular IPTV services, and is very important for IPTV providers since it represents the second most important r...
Conference Paper
We present Follow me!, a client application for Presence@FER, an ecosystem for rich presence which consolidates virtual, physical and online presence and relies on a publish/subscribe service for efficient filtering of presence updates. Follow me! simplifies the usage of rich presence service on smartphones and enables both explicit and implicit ch...
Conference Paper
Full-text available
YouTube is a huge video-sharing service with hundreds of millions of users and hundreds of thousands of videos being uploaded every day. Thus, recommendation of YouTube videos to a single user is a challenging problem which cannot be solved by simply reusing the prevailing recommendation methods. The paper presents a specific recommendation algorit...
Article
Full-text available
A sliding-window k-NN query (k-NN/w query) continuously monitors incoming data stream objects within a sliding window to identify k closest objects to a query. It enables effective filtering of data objects streaming in at high rates from potentially distributed sources, and offers means to control the rate of object insertions into result streams....
Conference Paper
Full-text available
Presence information - expressing user willingness and ability to communicate with other users across a set of devices and tools - represents an essential prerequisite for real-time communications. Although presence-related protocols have primarily emerged in conjunction with instant messaging systems, presence is today viewed as a primer service o...
Conference Paper
Full-text available
Presence management, i.e., the ability to automatically identify the status and availability of communication partners, is becoming an invaluable tool for collaboration in enterprise contexts. In this paper, we argue for efficient presence management by means of a holistic view of both physical context and virtual presence in online communication c...
Article
Full-text available
Web search engines designed on top of peer-to-peer (P2P) overlay networks show promise to enable attractive search scenarios operating at a large scale. However the design of effective indexing techniques for extremely large document collections still raises a number of open technical challenges. Resource sharing, self-organization, and low mainten...
Conference Paper
Full-text available
Numerous retrieval models have been defined within the field of information retrieval (IR) to produce a ranked and ordered list of documents relevant to a given query. Existing models are in general well-explored and thoroughly evaluated using traditionally centralized IR engines. However, the problem of producing global relevance scores to enable...
Article
Full-text available
In this paper we present the AlvisP2P IR engine, which enables efficient retrieval with multi-keyword queries from a global document collection available in a P2P network. In such a network, each peer publishes its local index and invests a part of its local computing resources (storage, CPU, bandwidth) to maintain a fraction of a global P2P index....
Conference Paper
Full-text available
Existing content-based publish/subscribe systems are designed assuming that all matching publications are equally relevant to a subscription. As we cannot know in advance the distribution of publication content, the following two unwanted situations are highly possible: a subscriber either receives too many or only few publications. In this paper w...
Article
Existing content-based publish/subscribe systems are designed assuming that all matching publications are equally relevant to a subscription. As we cannot know in advance the distribution of publication content, the following two unwanted situations are highly possible: a subscriber either receives too many or only few publications. In this paper w...
Article
Full-text available
The Workshop on Large-Scale Distributed Systems for Information Retrieval was a venue for seminal ideas on the design of systems for search. The workshop focused mainly on mechanisms for P2P IR, which is currently a highly popular research area, but it also had fruitful discussions and presentations on other architectures for large-scale systems. G...
Article
Full-text available
In this paper, we present a query-driven indexing/retrieval strategy for efficient full text retrieval from large document collections distributed within a structured P2P network. Our indexing strategy is based on two important properties: (1) the generated distributed index stores posting lists for carefully chosen indexing term combinations, and...
Conference Paper
Full-text available
The suitability of peer-to-peer (P2P) approaches for full-text Web retrieval has recently been questioned because of the claimed unacceptable bandwidth consumption induced by retrieval from very large document collections. In this contribution we formalize a novel indexing/retrieval model that achieves high performance, cost-efficient retrieval by...
Conference Paper
Full-text available
We describe a query-driven indexing framework for scalable text retrieval over structured P2P networks. To cope with the bandwidth consumption problem that has been identified as the major obstacle for full-text retrieval in P2P networks, we truncate posting lists associated with indexing features to a constant size storing only top-k ranked docume...
Article
In this paper, we present a query-driven indexing/retrieval strategy for efficient full text retrieval from large document collections distributed within a structured P2P network. Our indexing strategy is based on two important properties: (1) the generated distributed index stores posting lists for carefully chosen indexing term combinations that...
Conference Paper
Full-text available
Efficient subsumption checking, deciding whether a subscription or publication is subsumed by a set of previously defined subscriptions, is of para- mount importance for publish/subscribe systems. It provides the core system functionality—matching of publications to subscriber needs expressed as sub- scriptions—and additionally, reduces the overall...
Article
Full-text available
We present Alvis peers, a full-text P2P retrieval engine designed to offer retrieval performance comparable to centralized solutions while scaling to a very large number of peers. It is the result of our research efforts within the project Alvis1 European FP 6 STREP project ALVIS, http://www.alvis.info/ that aims at building a truly-distributed sem...
Conference Paper
Full-text available
Peer-to-peer networks have been identified as promising arc hitectural concept for developing search scenarios across digital lib rary collections. Digi- tal libraries typically offer sophisticated search over th eir local content, however, search methods involving a network of such stand-alone components are cur- rently quite limited. We present a...
Article
Full-text available
Web search over peer-to-peer (P2P) networks shows promise to become an alternative to the state-of-the-art search engines since P2P overlays offer means for decentralized search across widely-distributed document collections. However, the design of effective techniques for P2P indexing and retrieval raises a number of technical challenges due to po...