Axel Küpper

Axel Küpper
Technische Universität Berlin | TUB · Department of Telecommunication Systems

Prof. Dr.

About

169
Publications
67,425
Reads
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3,410
Citations
Additional affiliations
December 2011 - present
bitplaces GmbH
Position
  • Co-Founder
December 2009 - present
Technische Universität Berlin
Position
  • Professor (Associate)
December 2009 - present
Telekom Innovation Laboratories (T-Labs)
Position
  • Professor (Associate)

Publications

Publications (169)
Preprint
Full-text available
Supply chain data management faces challenges in traceability, transparency, and trust. These issues stem from data silos and communication barriers. This research introduces DIDChain, a framework leveraging blockchain technology, Decentralized Identifiers, and the InterPlanetary File System. DIDChain improves supply chain data management. To addre...
Conference Paper
Next generation mobile networks are poised to transition from monolithic structures owned and operated by single mobile network operators into multi-stakeholder networks where various parties contribute with infrastructure, resources, and services. However, a federation of networks and services brings along a crucial challenge: Guaranteeing secure...
Article
Full-text available
Most current cross-blockchain approaches focus on exchanging or transferring tokens between networks. While some concepts foster smart contract invocations across blockchains, they require multiple transactions and operate asynchronously. We present a concept enabling instant smart contract calls by creating synchronized client contracts on arbitra...
Preprint
Federated and decentralized networks supporting frequently changing system participants are a requirement for future Internet of Things (IoT) use cases. IoT devices and networks often lack adequate authentication and authorization mechanisms, resulting in insufficient privacy for entities in such systems. In this work we address both issues by desi...
Article
Full-text available
Zusammenfassung Der Digital Markets Act zielt darauf ab, den unilateralen Markteinfluss der Betreiber (sogenannte Gatekeeper) zentraler Plattformdienste, wie z. B. App-Stores, zu regulieren. In vielen Fällen zwingen Gatekeeper ihren Geschäftskunden (den Dienstanbietern) die Integration eigener Plattform-Identitätsdienste in ihren Diensten und Anwen...
Article
Full-text available
Self-sovereign identity is a digital identity paradigm that allows users and organizations to manage digital identity in a decentralized fashion without any central authority controlling the process of issuing identities and verifying assertions. Following this paradigm, implementations have emerged in recent years, with some having different under...
Article
A key challenge for mobile network operators in 6G is to bring together and orchestrate a variety of new emerging players of today's mobile eco-systems in order to provide economically viable and seamless mobile connectivity in the form of a multi-stakeholder service. With each new player, be it a cloud, edge, or hardware provider, the need for int...
Conference Paper
Full-text available
Decentralized services and applications provide a multitude of advantages for their users, such as improved privacy, control, and independence from third parties. Anyhow, decentralization comes at the cost of certain disadvantages, such as increased application complexity or communication overhead.This aggravates the development and deployment of d...
Preprint
Full-text available
p>Self-sovereign identity is the latest digital identity paradigm that allows users, organizations, and things to manage identity in a decentralized fashion without any central authority controlling the process of issuing identities and verifying assertions. Following this paradigm, implementations have emerged in recent years, with some having dif...
Preprint
Full-text available
Self-sovereign identity is the latest digital identity paradigm that allows users, organizations, and things to manage identity in a decentralized fashion without any central authority controlling the process of issuing identities and verifying assertions. Following this paradigm, implementations have emerged in recent years, with some having diffe...
Preprint
Full-text available
Decentralized services and applications provide a multitude of advantages for their users, such as improved privacy, control, and independence from third parties. Anyhow, decentralization comes at the cost of certain disadvantages, such as increased application complexity or communication overhead. This aggravates the development and deployment of...
Preprint
Full-text available
Decentralized services and applications provide a multitude of advantages for their users, such as improved privacy, control, and independence from third parties. Anyhow, decentralization comes at the cost of certain disadvantages, such as increased application complexity or communication overhead. This aggravates the development and deployment of...
Conference Paper
Full-text available
Trust-building mechanisms among network entities of different administrative domains will gain significant importance in 6G because a future mobile network will be operated cooperatively by a variety of different stakeholders rather than by a single mobile network operator. The use of trusted third party issued certificates for initial trust establ...
Preprint
Full-text available
Trust-building mechanisms among network entities of different administrative domains will gain significant importance in 6G because a future mobile network will be operated cooperatively by a variety of different stakeholders rather than by a single mobile network operator. The use of trusted third party issued certificates for initial trust establ...
Preprint
Full-text available
Cross-Blockchain communication has gained traction due to the increasing fragmentation of blockchain networks and scalability solutions such as side-chaining and sharding. With SmartSync, we propose a novel concept for cross-blockchain smart contract interactions that creates client contracts on arbitrary blockchain networks supporting the same exe...
Preprint
Full-text available
A key challenge for mobile network operators in 6G is to bring together and orchestrate a variety of new emerging players of today's mobile ecosystems in order to provide economically viable and seamless mobile connectivity in form of a multi-stakeholder service. With each new player, be it a cloud, edge or hardware provider, the need for interface...
Article
Full-text available
Over the past decade, blockchains and distributed ledger technologies have rapidly evolved. With increasing transaction volumes and the proliferation of decentralized applications based on smart contracts, a need for a deeper understanding arises. We structure the field that we term distributed ledger analytics.
Article
Full-text available
The ongoing digital transformation and internationalization of business processes cause a shift towards a more collaborative nature of processes. In such collaborations, different organizations execute separate parts of the process autonomously. This fragmentation leads to uncertainty regarding the correct execution of activities, the proper workfl...
Chapter
Decentralized Applications (dApps) are software applications where different parties interact over the Internet to achieve a common business goal. In contrast to centralized applications, not a singular entity has control over the whole system. The different parties interact in a peer-to-peer fashion. Without a centralized intermediary with the pow...
Preprint
Full-text available
Decentralized Applications (dApps) are software applications where different parties interact over the Internet to achieve a common business goal. In contrast to centralized applications, not a singular entity has control over the whole system. The different parties interact in a peer-to-peer fashion. Without a centralized intermediary with the pow...
Preprint
Full-text available
Recently, business processes started to become more collaborative by nature. Prominent examples of collaborative processes can be found in domains such as supply chain management, e-commerce, and in the realm of online multi-sided platforms. These types of collaborations are characterized by the fact that a collaborator's subprocess execution is us...
Preprint
Full-text available
In e-commerce, buyers and sellers trade digital products without knowing each other personally. Due to the lack of trust, a buyer prefers to pay for a product upon receipt. Also, the seller prefers to send a product after receiving the payment. With trusted escrows as intermediaries, the payment can be processed and independent parties can confirm...
Conference Paper
Full-text available
Recently, location-based services for Smart Cities became capable to proactively notify mobile users about hyper-local information or location-based reminders once users enter clearly-specified geographical regions, better known as geofences. Up to now, geofences are mostly designed by humans through the interactive design of circular or polygonal...
Conference Paper
Full-text available
Today, citizens of urban areas suffer from the serious health consequences of traffic-related air pollution. A common way to regulate traffic and indirectly the emission of pollutants is to charge drivers for the use of the road network. However, today's toll systems put their focus mainly on the optimization of the traffic flow by the introduction...
Preprint
Full-text available
This paper describes a new method, HMM gauge likelihood analysis, or GLA, of detecting anomalies in discrete time series using Hidden Markov Models and clustering. At the center of the method lies the comparison of subsequences. To achieve this, they first get assigned to their Hidden Markov Models using the Baum-Welch algorithm. Next, those models...
Conference Paper
Full-text available
Targeted advertising is an inherent part of the modern Web as we know it. For this purpose, personal data is collected at large scale to optimize and personalize displayed advertisements to increase the probability that we click them. Anonymity and privacy are also important aspects of the World Wide Web since its beginning. Activists and developer...
Conference Paper
Full-text available
As of today, web-based social communication platforms , such as WhatsApp, Twitter, or Facebook, are almost exclusively realized via centralized platforms, based on proprietary interfaces, protocols, and data formats. In consequence, even though social communication being a decentralized, peer-to-peer phenomenon, web-based communication today is imp...
Article
Full-text available
Supply Chain Traceabiliy is one of the most promising use cases to benefit from blockchain characteristics such as decentralization, immutability and transparency, without requiring to build prior trust relationships among entities. A plethora of blockchain-based supply chain traceability solutions has been proposed recently. However, current syste...
Preprint
Full-text available
As of today, web-based social communication platforms , such as WhatsApp, Twitter, or Facebook, are almost exclusively realized via centralized platforms, based on proprietary interfaces, protocols, and data formats. In consequence, even though social communication being a decentralized, peer-to-peer phenomenon, web-based communication today is imp...
Conference Paper
Full-text available
With the advent of small, energy-efficient, interconnected and cheap air pollution sensors, communities all over the world have begun to drive forward the expansion of city-wide sensor networks in order to get a holistic picture of the air pollution level that the citizens are exposed to in their daily life. Unfortunately , the resulting insights a...
Preprint
Growing consumer awareness as well as manufacturers' internal quality requirements lead to novel demands on supply chain traceability. Existing centralized solutions suffer from isolated data storage and lacking trust when multiple parties are involved. Decentralized blockchain-based approaches attempt to overcome these shortcomings by creating dig...
Conference Paper
Full-text available
Growing consumer awareness as well as manufac-turers' internal quality requirements lead to novel demands on supply chain traceability. Existing centralized solutions suffer from isolated data storage and lacking trust when multiple parties are involved. Decentralized blockchain-based approaches attempt to overcome these shortcomings by creating di...
Chapter
Full-text available
The role of personal data gained significance across all business domains in past decades. Despite strict legal restrictions that processing personal data is subject to, users tend to respond to the extensive collection of data by service providers with distrust. Legal battles between data subjects and processors emphasized the need of adaptations...
Article
Full-text available
Many potential cloud consumers are overburdened by the challenges persisting when discovering, assessing, and selecting contemporary Cloud Service offerings: the cloud market is vast and fast-moving, the selection criteria are ambiguous, service knowledge is scattered through the Internet, and features as well as prices are complex and incomparable...
Conference Paper
Full-text available
Since the beginnings of the World Wide Web, advertisements are an inherent part of it. It enables business models that allow users to consume content and services free of charge, while their providers generate revenue with every visitor. These advertisements are specifically tailored to each user to increase the probability that a user actually cli...
Article
Full-text available
Spatiotemporal datasets have become increasingly available with the introduction of a various set of applications and services trac- ing the behavior of moving objects. Recently, there has been a high demand in understanding these datasets using spatiotemporal analytics. While being considered of high value, spatiotemporal analytics did not yet see...
Conference Paper
Full-text available
Online Social Networks (OSN) are mostly closed, proprietary services that disallow interoperability with other OSN services. In the area of decentralized OSN services, several protocols and services have been proposed that attempt to implement interoperability for distinct aspects of OSN services in heterogeneous federations of OSN services. In thi...
Conference Paper
Full-text available
Clustering algorithms are recently regaining attention with the availability of large datasets and the rise of parallelized computing architectures. However, most clustering algorithms do not scale well with increasing dataset sizes and require proper parametrization for correct results. In this paper we present A-BIRCH, an approach for automatic t...
Article
Full-text available
Clustering algorithms are recently regaining attention with the availability of large datasets and the rise of parallelized computing architectures. However, most clustering algorithms suffer from two drawbacks: they do not scale well with increasing dataset sizes and often require proper parametrization which is usually difficult to provide. A ver...
Conference Paper
Full-text available
Mobile traffic analysis is typically performed on large datasets, which are collected by telecommunication operators within their network. To protect the privacy of subscribers, data is often anonymized. Therefore it is challenging to conceive mobility models of subscribers, because ground truth is costly to acquire. In this paper we demonstrate ho...
Conference Paper
Contemporary multi-cloud application deployments require increasingly complex security architectures, especially within federated environments. However, increased complexity often leads to higher efforts and raised costs for managing and securing those applications. This publication establishes an economical and comprehensive security architecture...
Article
Full-text available
Cross-domain identity management remains a major challenge for potential WebRTC adopters. In order to provide a global web-based communication system, it is critical to locate the destination called party, map the identity to the user device, and provide mutual authentication for both caller and called party. In this paper, we present a novel ident...
Conference Paper
Full-text available
The upcoming WebRTC-based browser-to-browser communication services present new challenges for user discovery in peer-to-peer mode. Even more so, if we wish to enable different web communication services to interact. This paper presents Identity Mapping and Discovery Service (IMaDS), a global, scalable, service independent discovery service that en...
Conference Paper
Full-text available
An ever-increasing number of today's mobile applications take advantage of location-based services (LBS) in order to proactively notify mobile users about location-dependent content or to execute location-dependent actions once the user enters or leaves a dedicated zone. The proactive LBS are thereby responsible to track the user's position energy-...
Conference Paper
Full-text available
As of today, communication habits are shifting towards Online Social Network (OSN) services such as WhatsApp or Facebook. Still, OSN platforms are mostly built in a closed, proprietary manner that disallows users from communicating seamlessly between different OSN services. These lock-in effects are used to discourage users to migrate to other serv...
Conference Paper
When trying to discover, assess, and select cloud services, companies face many challenges, such as fast-moving markets, vast numbers of offerings, and highly ambiguous selection criteria. This publication presents the Open Service Compendium (OSC), an information system which supports businesses in their discovery, assessment and cloud service sel...
Conference Paper
Full-text available
Usable encryption is a challenging task especially in hospital environments, where on the one hand legal regulations require to apply encryption technologies and on the other special usability requirements have to be fulfilled. A study has to be conducted to identify use cases and requirements and learn how to integrate the encryption technology At...
Research
Full-text available
When people interact with each other, they implicitly make use of context information while intuitively deducing and interpreting their actual situation. Compared to humans, IT infrastructures cannot easily take advantage of context information in interactions. Typically, context information has to be provided explicitly. Recently, cellular network...
Conference Paper
Full-text available
Today, proactive location-based services (LBS) are gaining momentum as mobile devices became able to track the users' position in the background without notable battery drain. They are used in several application areas like location-based marketing or gaming to deliver notifications, e.g. coupons, proactively to the user once a defined geographical...
Conference Paper
Full-text available
Two of the most popular applications of smartphones are online social networking and playing back music. In this paper, we present the design and implementation of a prototype that combines those usages by creating an architecture that allows the generation and playback of group music playlists that are based on the musical taste of individual gues...
Conference Paper
Full-text available
With the rise of smart mobile devices, context-aware mobile applications became an integral part of our everydaylife. However, testing, evaluating or demonstrating context-aware mobile applications for outdoor environments remains a resource-intensive and cumbersome task. The investigations need to be conducted in real-world experiments in order to...
Conference Paper
Full-text available
The rise of smart mobile devices created new opportunities for electronic and mobile participation. These devices provide means to sense the current environment citizens are situated in, which can be then used to carry out targeted opinion polls. The context-aware polling system FlashPoll takes advantage of this notion and enables the conduct of sh...
Conference Paper
Full-text available
Advancements in web real time technologies are revolutionizing the way communication is taking place, where new emerging web services are confronting the traditional Telco operated communication services. This has led to the development of new web-centric service architecture that will allow service providers to provide their communication services...
Conference Paper
Full-text available
Online Social Network (OSN) platforms have become an important part of our everyday online lives. We communicate, share content, and organize meetings and events using social platforms and services. However, even though there is a strong trend towards OSN services to become the main communication medium, most OSN platforms are still proprietary, cl...
Conference Paper
Full-text available
Today, sharing information is ubiquitous in a connected world. However, several disadvantages exist, such as the loss of control over data or unwanted data processing and analysis by providers. A central data storage, which is applied by Online Social Networks (OSN), such as Facebook or driven by the government, such as storing medical health data...
Conference Paper
Full-text available
With the advent of the Internet of Things (IoT), communication between connected machines has become necessity. We simulate the communication of IoT by short-lived instant messaging for group communication. Group communication security requires such measures as group forward and backward secrecy and perfect forward secrecy. We satisfy these securit...
Conference Paper
Full-text available
Whenever multiple service providers and high demanding service customers communicate with each other, the need of compliance to legal regulations and enterprise guidelines increases the expectations on technologies and systems used to ensure security and data privacy. Regarding the challenge of managing access rules and enforcing authorization to d...
Conference Paper
Full-text available
As of today, even though there is a strong trend of Online Social Networks (OSNs) becoming the main communication medium, OSN platforms are still mostly proprietary, closed solutions, which are not capable to seamlessly communicate with each other. The research project SONIC (SOcial Network InterConnect) proposes a holistic standard for inter-platf...
Article
The number of datasets in the Linking Open Data Cloud increases rapidly and has reached a total of 295 by September 2011. Various content domains are covered by those datasets, such as Media, Government or Geographic Data, all directly linked to each other building a huge graph of interlinked structured data. However, data describing the mobile net...