Martin Werner

Martin Werner
Leibniz Universität Hannover · Institut für Kartographie und Geoinformatik

Jun.-Prof. Dr.

About

70
Publications
15,002
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1,165
Citations

Publications

Publications (70)
Conference Paper
In this work, we present a model for building type classifica tion from Twitter text messages (tweets) by employing geo-spatial text mining methods. First, we apply standard text pre-processing methods and convert the tweets into sentence vectors using fastText. For classification, we apply a feedforward network with two fully connected hidden laye...
Conference Paper
Understanding urban dynamics requires detailed insights into urban land use. On the most fine-grained level this classification is done on single building instance levels. This level of detail can hardly be solved using remote sensing only, but requires complementary data. Social media images are a promising additional image data source since they...
Article
Full-text available
This article addresses the question of mapping building functions jointly using both aerial and street view images via deep learning techniques. One of the central challenges here is determining a data fusion strategy that can cope with heterogeneous image modalities. We demonstrate that geometric combinations of the features of such two types of i...
Conference Paper
Understanding urbanization and planning for theupcoming changes require detailed knowledge about the placeswhere people live and work. Thus, knowing the usage of buildingsis inevitable to distinguish between residential and commercialplaces. Assessing the usage of buildings from an aerial perspectivealone is challenging and results in unresolveable...
Article
Full-text available
By the year 2050, it is expected that about 68% of global population will live in cities. To understand the emerging changes in urban structures, new data sources like social media must be taken into account. In this work, we conduct a feature space analysis of geo-tagged Twitter text messages from the Los Angeles area and a geo-spatial text mining...
Conference Paper
A fundamental problem in indoor location-based services is to compute the meaning of location with respect to an indoor location model. One specific challenge in this area is represented by the central tradeoff between two philosophies: a decent amount of the community tries to provide high-quality, high-fidelty models investing specialized knowled...
Chapter
Currently, we experience a growing number of highly sophisticated digital services in virtually every domain of our lives. Tightly coupled to this observation is the appearance of Big Data and consequently the need for Data Science. When trying to transform data into value, communication is key. However, communication can easily get ambiguous and m...
Chapter
A fundamental problem in indoor location-based services is to compute the meaning of location with respect to an indoor location model. One specific challenge in this area is represented by the central tradeoff between two philosophies: a decent amount of the community tries to provide high-quality, high-fidelity models investing specialized knowle...
Conference Paper
Urban geo-information extraction from remote sensing data has been an active research field for decades. As a complementary source of geo-information, huge amounts of social media data are generated every day, such as pictures (e.g. from Facebook or Instagram) or text messages (e.g. from Twitter). Towards a joint exploitation of remote sensing data...
Chapter
Der digitale Wandel verändert alle Bereiche von Wirtschaft und Gesellschaft. Er erfasst nicht nur einzelne Medien, sondern ganze Prozesse und Branchen: Damit die Wirtschaft die digitale Transformation bewältigen kann, müssen die Netzinfrastruktur, der Zuschnitt der Plattformen und die Bandbreite stimmen, denn Daten müssen zur richtigen Zeit an den...
Conference Paper
Abstract—In this paper, we present a novel anomaly detection method which addresses the main challenge of self-organizing industrial systems: the state space explosion. In particular, the flexibility and dynamic nature of such systems result in an exponentially growing number of possible execution plans. To handle this problem, we propose to learn...
Conference Paper
Trajectory analysis is a central problem in the era of big data due to numerous interconnected mobile devices generating unprecedented amounts of spatio-temporal trajectories. Unfortunately, datasets of spatial trajectories are quite difficult to analyse because of the computational complexity of the various existing distance measures. A significan...
Conference Paper
Finding the location of a mobile user is a classical and important problem in pervasive computing, because location provides a lot of information about the situation of a person from which adaptive computer systems can be created. While the inference of location outside buildings is possible with GPS or similar satellite systems, these are unavaila...
Conference Paper
Indoor navigation and location-awareness are important and growing research areas due to the interest of mobile users in location-based services comparable to outside services. However, indoor positioning is a very hard task. Without installing dedicated hardware into a building, indoor positioning is a problem with inherent ambiguity. Using Wi-Fi...
Article
Lots of existing work addresses the analysis of Bitcoin's publicly available transaction graph. There are evaluations of the user's anonymity and privacy, but no proper measurements of the underlying network. This paper presents novel insights about Bitcoin's P2P network, with a focus on the distribution among autonomous systems. The resilience of...
Conference Paper
This paper proposes a length-independent feature representation of sets of strings based on Bloom filters called BACR for similarity search in databases. Further, we show how a Z-curve-based discretization of geospatial trajectories can be used in order to search for similar trajectories in large databases. Additionally to the already-known estimat...
Conference Paper
Nowadays, many daily duties being of a private as well as of a business nature are handled with the help of online services. Due to migrating formerly local desktop applications into clouds (e.g., Microsoft Office Online, etc.), services become available by logging in into a user account through a web browser. But possibilities for authenticating a...
Conference Paper
Alternative routes have found many applications in navigation scenarios. However, alternative routes have only been introduced recently for the indoor space due to the complexity of these environments. Furthermore, the number of alternative routes in buildings can be quite high. With this paper, we propose to organize sets of alternative routes by...
Conference Paper
Modern databases tailored to highly distributed, fault tolerant management of information for big data applications exploit a classical data structure for reducing disk and network I/O as well as for managing data distribution: The Bloom filter. This data structure allows to encode small sets of elements, typically the keys in a key-value store, in...
Chapter
Online-Shops verfügen über etablierte Techniken zur systematischen Erfassung von Kundendaten sowie dem Surf- und Kaufverhalten. Neue Ansätze zur Kundenerfassung und personalisierter Kundenansprache werden infolgedessen auch im stationären Handel gesucht, um Kunden und Betreibern einen Mehrwert zu bieten, der in der digitalen Welt bereits Standard i...
Conference Paper
Full-text available
Bitcoin has become increasingly important in recent years. The exchange rate raised from $14 in January 2013 up to $240 in April 2013 and even $900 in early 2014. In this paper, we present novel insights about Bitcoin's peer-to-peer (P2P) network with a special focus on its distribution among distinct autonomous systems. We traversed Bitcoin's P2P...
Conference Paper
There are lots of innovative use cases possible that build on a shortest route between two locations together with a set of alternatives that are highly different yet short. Imagine, for example, a complicated building like an airport, where passengers can consult a computer terminal to get navigation advices to a desired goal. By scanning the boar...
Conference Paper
Due to the increasing popularity of location-based services, the need for reliable and cost-effective indoor positioning methods is rising. As an alternative to radio-based localization methods, in 2011, we introduced MoVIPS (Mobile Visual Indoor Positioning System), which is based on the idea to extract visual feature points from a query image and...
Conference Paper
The time-series nature of human movement inside buildings can be exploited for common tasks of location-based computing. With this paper, we propose to use Wi-Fi signal strength measurements directly to infer the trajectory in comparison with a database of trajectories removing the need for accurate map information or fingerprint databases. A traje...
Article
Indoor positioning has become very popular in recent years. Application scenarios range from pedestrian navigation over asset tracking to automated industrial production. With the variety of uses, also the diversity of indoor positioning methods, technologies, and systems grows. This article explains how indoor positioning works; describes the basi...
Conference Paper
Interest dissemination in constrained environments such as wireless sensor networks utilizes Bloom filters commonly. A Bloom filter is a probabilistic data structure of fixed length, which can be used to encode the set of sensor nodes to be awake. In this way an application can disseminate interest in specific sensor nodes by broadcasting the Bloom...
Conference Paper
Mobile Edge Computing proposes co-locating computing and storage resources at base stations of cellular networks. It is seen as a promising technique to alleviate utilization of the mobile core and to reduce latency for mobile end users. Due to the fact that Mobile Edge Computing is a novel approach not yet deployed in real-life networks, recent wo...
Article
Bitcoin has become increasingly important for several years. While being declared dead in the meantime, it got a boost in 2011. The exchange rate increased from $14 in January 2013 up to $240 in April 2013 and even $900 in early 2014. Lots of existing work addresses the analysis of the publicly available transaction graph. There are evaluations of...
Conference Paper
The rapid deployment of smartphones as all-purpose mobile computing systems has led to a wide adoption of wireless communication systems such as Wi-Fi and Bluetooth in mobile scenarios. Both communication systems leak information to the surroundings during operation. This information has been used for tracking and crowd density estimations in liter...
Conference Paper
With this paper, we propose a novel semantic compression scheme for GPS trajectories which exploits map knowledge for data reduction. Therefore, the compression is integrated into a simple map matching scheme and shows superior performance with respect to the compression ratio. In contrast to other compression schemes including compressed GPX files...
Conference Paper
This paper investigates a complication of the classical Traveling Salesman Problem, which arises due to multiple points of interest with functional equivalence. While the classical Traveling Salesman Problem tries to find a shortest tour visiting each point in a set exactly once, we consider the challenge of finding the shortest tour visiting each...
Conference Paper
Matrix codes enable a coupling between virtual and physical worlds for ubiquitous computing applications. With this paper, we propose a technique, which can be used to increase the amount of information contained in a matrix barcode in a backward compatible way. This enables applications to fully utilize the wide spread of QR Codes or Data Matrix C...
Conference Paper
Location information is one of the most important information sources in ubiquitous computing scenarios. However, a cheap and global indoor positioning solution offering a sufficiently high accuracy and precision for most ubiquitous computing applications without much calibration effort is not yet available. In this paper we present a backtracking...
Chapter
Der Einfluss der Informationstechnologie auf die Wirtschaft nimmt ständig zu. Der geschickte Einsatz von Information und Kommunikation kann wesentlich zum Erfolg eines Unternehmens beitragen. Die ständig wachsende Leistungsfähigkeit von mobilen Endgeräten ermöglicht durch den Einsatz von Kontextinformationen wie dem Aufenthaltsort des Endgerätes re...
Conference Paper
Indoor positioning with smartphones in ubiquituos computing scenarios still poses some problems with respect to accuracy and precision as well the need for a calibrated infrastructure and map data. This paper presents a method for indoor positioning based on the combination of 802.11 WLAN fingerprinting using weighted kNN and a simple indoor moveme...
Conference Paper
Full-text available
With the increasing computational power of mobile devices and the increase in the usage of ordinary location-based services, the area of indoor location-based services is of growing interest. Nowadays indoor location-based services are used mainly for personalized information retrieval of maps and points of interest. Advanced location-based functio...
Conference Paper
Indoor navigation systems guide users through complex buildings, which they do not know in advance. The complexity of public buildings such as airports, train stations or hospitals leads to new variants of well-studied NP-hard optimization problems such as the Traveling Salesman Problem, where most of the classical approximations are not directly a...
Article
Location-based services (LBSs) are emerging fast, and the problems with privacy are growing with them. Although a platform for LBSs can provide the user with high-quality LBS browsing and powerful mechanisms to reduce the amount of location data transmitted, such a platform is dangerous because it has to manage the location data of the users and th...
Conference Paper
Full-text available
At present, the rapid development of Online Social Networks (OSN) has strong influence on our global community'scommunication patterns. This primarily manifests in an exponentially increasing number of users of Social Network Services (SNS) such as Face book or Twitter. A fundamental problem accompanied by the utilization of OSNs is given by an ins...
Conference Paper
Indoor Navigation is becoming a more and more important topic. It is a key tool for the integration of disabled people into environments which they are not familiar with. With this paper we want to address the problem of indoor navigation being much more complex than outdoor navigation with a thorough modelling of queries which a indoor navigation...
Conference Paper
The integration of mobile devices into business processes is a challenging but promising task. We designed a system that shows the possibility of constructing software systems that accomplish the difficult achievement of a system that simplifies tasks for businesses as well as for their customers. We designed a very simple and straight-forward work...
Conference Paper
Location-Based Services are emerging fast and the problems with privacy are growing with them. While a platform for Location-Based Services can provide the user with high-quality Location-Based Service browsing and powerful mechanisms to reduce the amount of location data transmitted such a platform is dangerous as it has to manage the location dat...

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