1,721,278 research outputs found
Access Control Within MQTT-based IoT environments
Full text linkIoT applications, which allow devices, companies, and users to join the IoT ecosystems, are growing in popularity since they increase our lifestyle quality day by day. However, due to the personal nature of the managed data, numerous IoT applications represent a potential threat to user privacy and data confidentiality.
Insufficient security protection mechanisms in IoT applications can cause unauthorized users to access data. To solve this security issue, the access control systems, which guarantee only authorized entities to access the resources, are proposed in academic and industrial environments. The main purpose of access control systems is to determine who can access specific resources under which circumstances via the access control policies. An access control model encapsulates the defined set of access control policies.
Access control models have been proposed also for IoT environments to protect resources from unauthorized users. Among the existing solutions, the proposals which are based on Attribute-Based Access Control (ABAC) model, have been widely adopted in the last years. In the ABAC model, authorizations are determined by evaluating attributes associated with the subject, object, and environmental properties. ABAC model provides outstanding flexibility and supports fine-grained, context-based access control policies. These characteristics perfectly fit the IoT environments.
In this thesis, we employ ABAC to regulate the reception and the publishing of messages exchanged within MQTT-based IoT environments. MQTT is a standard application layer protocol that enables the communication of IoT devices.
Even though the current access control systems tailored for IoT environments in the literature handle data sharing among the IoT devices by employing various access control models and mechanisms to address the challenges that have been faced in IoT environments, surprisingly two research challenges have still not been sufficiently examined.
The first challenge that we want to address in this thesis is to regulate data sharing among interconnected IoT environments. In interconnected IoT environments, data exchange is carried out by devices connected to different environments. The majority of proposed access control frameworks in the literature aimed at regulating the access to data generated and exchanged within a single IoT environment by adopting centralized enforcement mechanisms. However, currently, most of the IoT applications rely on IoT devices and services distributed in multiple IoT environments to satisfy users’ demands and improve their functionalities.
The second challenge that we want to address in this thesis is to regulate data sharing within an IoT environment under ordinary and emergency situations. Recent emergencies, such as the COVID-19 pandemic, have shown that proper emergency management should provide data sharing during an emergency situation to monitor and possibly mitigate the effect of the emergency situation. IoT technologies provide valid support to the development of efficient data sharing and analysis services and appear well suited for building emergency management applications. Additionally, IoT has magnified the possibility of acquiring data from different sensors and employing these data to detect and manage emergencies. An emergency management application in an IoT environment should be complemented with a proper access control approach to control data sharing against unauthorized access.
In this thesis, we do a step to address two open research challenges related to data protection in IoT environments which are briefly introduced above. To address these challenges, we propose two access control frameworks rely on ABAC model: the first one regulates data sharing among interconnected MQTT-based IoT environments, whereas the second one regulates data sharing within MQTT-based IoT environment during ordinary and emergency situations.IoT applications, which allow devices, companies, and users to join the IoT ecosystems, are growing in popularity since they increase our lifestyle quality day by day. However, due to the personal nature of the managed data, numerous IoT applications represent a potential threat to user privacy and data confidentiality.
Insufficient security protection mechanisms in IoT applications can cause unauthorized users to access data. To solve this security issue, the access control systems, which guarantee only authorized entities to access the resources, are proposed in academic and industrial environments. The main purpose of access control systems is to determine who can access specific resources under which circumstances via the access control policies. An access control model encapsulates the defined set of access control policies.
Access control models have been proposed also for IoT environments to protect resources from unauthorized users. Among the existing solutions, the proposals which are based on Attribute-Based Access Control (ABAC) model, have been widely adopted in the last years. In the ABAC model, authorizations are determined by evaluating attributes associated with the subject, object, and environmental properties. ABAC model provides outstanding flexibility and supports fine-grained, context-based access control policies. These characteristics perfectly fit the IoT environments.
In this thesis, we employ ABAC to regulate the reception and the publishing of messages exchanged within MQTT-based IoT environments. MQTT is a standard application layer protocol that enables the communication of IoT devices.
Even though the current access control systems tailored for IoT environments in the literature handle data sharing among the IoT devices by employing various access control models and mechanisms to address the challenges that have been faced in IoT environments, surprisingly two research challenges have still not been sufficiently examined.
The first challenge that we want to address in this thesis is to regulate data sharing among interconnected IoT environments. In interconnected IoT environments, data exchange is carried out by devices connected to different environments. The majority of proposed access control frameworks in the literature aimed at regulating the access to data generated and exchanged within a single IoT environment by adopting centralized enforcement mechanisms. However, currently, most of the IoT applications rely on IoT devices and services distributed in multiple IoT environments to satisfy users’ demands and improve their functionalities.
The second challenge that we want to address in this thesis is to regulate data sharing within an IoT environment under ordinary and emergency situations. Recent emergencies, such as the COVID-19 pandemic, have shown that proper emergency management should provide data sharing during an emergency situation to monitor and possibly mitigate the effect of the emergency situation. IoT technologies provide valid support to the development of efficient data sharing and analysis services and appear well suited for building emergency management applications. Additionally, IoT has magnified the possibility of acquiring data from different sensors and employing these data to detect and manage emergencies. An emergency management application in an IoT environment should be complemented with a proper access control approach to control data sharing against unauthorized access.
In this thesis, we do a step to address two open research challenges related to data protection in IoT environments which are briefly introduced above. To address these challenges, we propose two access control frameworks rely on ABAC model: the first one regulates data sharing among interconnected MQTT-based IoT environments, whereas the second one regulates data sharing within MQTT-based IoT environment during ordinary and emergency situations
Efficient ABAC based information sharing within MQTT environments under emergencies
Full text linkRecent emergencies, such as the COVID-19 pandemic have shown how timely information sharing is essential to promptly and effectively react to emergencies. Internet of Things has magnified the possibility of acquiring information from different sensors and using it for emergency management and response. However, it has also amplified the potential of information misuse and unauthorized access to information by untrusted users. Therefore, this paper proposes an access control framework tailored to MQTT-based IoT ecosystems. By leveraging Complex Event Processing, we can enforce controlled and timely data sharing in emergency and ordinary situations. The system has been tested with a case study that targets patient monitoring during the COVID-19 pandemic, showing promising results
Access Control Enforcement in IoT: state of the art and open challenges in the Zero Trust era
No full textID-based rendering of silhouettes on GPU
No full textWhen rendering object-silhouettes preprocessing is generally done primarily on the CPU. To this end primitive normals must be made consistent and the silhouette-edges need to be extracted every time the view-point is changed. In this paper we propose a pure image-based GPU-method where IDs of triangles are rendered to a texture and silhouettes are extracted based on the information stored in that texture. With this method the geometry does not need to be preprocessed or reprocessed when the view-point or the geometry is changed. Another important advantage of the proposed method over any Z-buffer based method is that it does not require any threshold value to compare against the difference between depth-values of the neighboring pixels which is difficult to adjust in perspective projection. © The Eurographics Association 2010.Lightworks nVidia crew vizNET Mapping Solution
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Reflections of language use as a mask in literary translation: An analysis of a bilingual author/translator
No full textBu tez çalışmasında, dünyayı algılama biçimimizi etkileyen, anlam yaratma gücü olan, toplumların ve kişilerin kimlik inşasında önemli yer tutan, aynı zamanda bir amaç taşıma işlevi de gören dilin, bir yazar/çevirmen tarafından nasıl arkasına sığınılan bir maske olarak kullanılabileceği bir "öz-çeviri" örneği üzerinden ele alınacaktır. Bu bağlamda yazar/çevirmenin dilin ardına sığınma eğiliminin altında yatan olası sebepler ve bu sebeplerin kültürel, sosyal ve psikolojik etkileri yazar/çevirmen ve çevirmenin kendilerini ifade etme biçimlerini nasıl etkilediği çeviribilim çerçevesinde ele alınacak, dilin her iki çeviri sürecinde uğradığı değişimler ve bu değişimlerin olası nedenleri tespit edilecektir. Çalışmada Hans J. Vermeer'in her çeviri eyleminin bir amacı olduğunu ve her çevirinin amacının kendi gerekliliklerine özgü olduğu vurgusunu yaptığı Skopos kuramı üzerinden yazar/çevirmenin değişen yazma amacıyla beraber kendini çevirmesi bağlamında "öz-çeviri" kavramı temel alınarak çeviribilim odaklı bir inceleme yapılacak, bir ''öz-çeviri" olan Elif Batuman'ın kaleme aldığı The Idiot (2018) adlı kaynak metin ve metnin Hande Dönmez tarafından Türkçeye kazandırılan Budala (2023) adlı çevirisi karşılaştırmalı olarak değerlendirilerek her iki çeviride uygulanan çevirmen kararları sonucunda kullanılan çeviri stratejileri tespit edilecek, bu doğrultuda dilin maske olarak nasıl kullanıldığı, çift dilli ve çift kültürlü olmanın yazar/çevirmene sağladığı imkânlar, dil-kültür ilişkisi ve bu ilişkinin çeviri metinlere yansımaları, çift dilli bir yazar/çevirmen olarak yazarın "öz-çeviri" yoluyla farklı bir kültürde kendine nasıl yeni bir benlik inşa edip var oluş kazandırdığı ve çeviri amaçları doğrultusunda kaynak ve erek metinde uygulanan çevirmen kararları örnekler üzerinden incelenerek çözümlenmeye çalışılacaktır.This thesis will examine how language, which influe
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