7 research outputs found
5th International Open and Distance Learning Conference Proceedings Book = 5. Uluslararası Açık ve Uzaktan ĂÄrenme Konferansı Bildiri Kitabı
In celebration of our 40th anniversary in open and distance learning, we are happy and proud to organize the 5th International Open & Distance Learning Conference- IODL 2022, which was held at Anadolu University, EskiĆehir, TĂŒrkiye on 28-30 September 2022. After the conferences in 2002, 2006, 2010, and 2019, IODL 2022 is the 5th IODL event hosted by Anadolu University Open Education System (OES)
Proceedings of the Conference on Production Systems and Logistics: CPSL 2022
[no abstract available
Privacy-preserving spatiotemporal multicast for mobile information services
Mobile devices have become essential for accessing information services anywhere at any time. While the so-called geographic multicast (geocast) has been considered in detail in existing research, it only focuses on delivering messages to all mobile devices that are currently residing within a certain geographic area. This thesis extends this notion by introducing a Spatiotemporal Multicast (STM), which can informally be described as a "geocast into the past". Instead of addressing users based on their current locations, this concept relates to the challenge of sending a message to all devices that have resided within a geographic area at a certain time in the past. While a wide variety of applications can be envisioned for this concept, it presents several challenges to be solved. In order to deliver messages to all past visitors of a certain location, an STM service would have to fully track all user movements at all times. However, collecting this kind of information is not desirable considering the underlying privacy implications, i.e., users may not wish to be identified by the sender of a message as this can disclose sensitive personal information. Consequently, this thesis aims to provide a privacy-preserving notion of STM. In order to realize such a service, this work first presents a detailed overview of possible applications. Based on those, functional, non-functional, as well as security and privacy objectives are proposed. These objectives provide the foundation for an in-depth literature review of potential mechanisms for realizing an STM service. Among the suggested options, the most promising relies on Rendezvous Points (RPs) for datagram delivery. In simple terms, RPs represent "anonymous mailboxes" that are responsible for certain spatiotemporal regions. Messages are deposited at RPs so that users can retrieve them later on. Protecting the privacy of users then translates to obfuscating the responsibilities of RPs for specific spatiotemporal regions. This work proposes two realizations: CSTM, which relies on cryptographic hashing, and OSTM, which considers the use of order-preserving encryption in a CAN overlay. Both approaches are evaluated and compared in detail with respect to the given objectives. While OSTM yields superior performance-related properties, CSTM provides an increased ability of protecting the privacy of users.MobilgerĂ€te bilden heute die Grundlage allgegenwĂ€rtiger Informationsdienste. WĂ€hrend der sogenannte geografische Multicast (Geocast) hier bereits ausfĂŒhrlich erforscht worden ist, so bezieht sich dieser nur auf GerĂ€te, welche sich aktuell innerhalb einer geografischen Zielregion befinden. Diese Arbeit erweitert dieses Konzept durch einen rĂ€umlich-zeitlichen Multicast, welcher sich informell als "Geocast in die Vergangenheit" beschreiben lĂ€sst. Dabei wird die Zustellung einer Nachricht an alle Nutzer betrachtet, die sich in der Vergangenheit an einem bestimmten Ort aufgehalten haben. WĂ€hrend eine Vielzahl von Anwendungen fĂŒr dieses Konzept denkbar ist, so ergeben sich hier mehrere Herausforderungen. Um Nachrichten an ehemalige Besucher eines Ortes senden zu können, mĂŒsste ein rĂ€umlich-zeitlicher Multicast-Dienst die Bewegungen aller Nutzer vollstĂ€ndig erfassen. Aus GrĂŒnden des Datenschutzes ist das zentralisierte Sammeln solch sensibler personenbezogener Daten jedoch nicht wĂŒnschenswert. Diese Arbeit befasst sich daher insbesondere mit dem Schutz der PrivatsphĂ€re von Nutzern eines solchen Dienstes. Zur Entwicklung eines rĂ€umlich-zeitlichen Multicast-Dienstes erörtert diese Arbeit zunĂ€chst mögliche Anwendungen. Darauf aufbauend werden funktionale, nicht-funktionale, sowie Sicherheits- und PrivatsphĂ€re-relevante Anforderungen definiert. Diese bilden die Grundlage einer umfangreichen Literaturrecherche relevanter Realisierungstechniken. Der vielversprechendste Ansatz basiert hierbei auf der Hinterlegung von Nachrichten in sogenannten Rendezvous Points. Vereinfacht betrachtet stellen diese "anonyme BriefkĂ€sten" fĂŒr bestimmte rĂ€umlich-zeitliche Regionen dar. Nachrichten werden in diesen so hinterlegt, dass legitime EmpfĂ€nger sie dort spĂ€ter abholen können. Der Schutz der Nutzer-PrivatsphĂ€re entspricht dann der Verschleierung der ZustĂ€ndigkeiten von Rendezvous Points fĂŒr verschiedene rĂ€umlich-zeitliche Regionen. Diese Arbeit schlĂ€gt zwei AnsĂ€tze vor: CSTM, welches kryptografische Hashfunktionen nutzt, sowie OSTM, welches ordnungserhaltende VerschlĂŒsselung in einem CAN Overlay einsetzt. Beide Optionen werden detailliert analytisch sowie empirisch bezĂŒglich ihrer Diensteigenschaften untersucht und verglichen. Dabei zeigt sich, dass OSTM vorteilhaftere Leistungseigenschaften besitzt, wĂ€hrend CSTM einen besseren Schutz der Nutzer-PrivatsphĂ€re bietet
Design of a Controlled Language for Critical Infrastructures Protection
We describe a project for the construction of controlled language for critical infrastructures protection (CIP). This project originates
from the need to coordinate and categorize the communications on CIP at the European level. These communications can be physically
represented by official documents, reports on incidents, informal communications and plain e-mail. We explore the application of
traditional library science tools for the construction of controlled languages in order to achieve our goal. Our starting point is an
analogous work done during the sixties in the field of nuclear science known as the Euratom Thesaurus.JRC.G.6-Security technology assessmen
Simulative Performance Evaluation of the Temporary Pseudonym Method for Protecting Location Information in GSM Networks
The information about the location of a mobile user belongs to the most sensitive data within mobile communication networks. One possibility to protect it especially against curious insiders with access to the network consists of storing the actual information in so-called âhome trusted devicesâ and using temporary pseudonyms for user registration in the network databases. This paper presents a detailed OPNET simulation and evaluation of the signalling cost of this approach compared to standard GSM