Browsing by study line "Networking and Services"

The semantic shifts in natural language is a well established phenomenon and have been studied for many years. Similarly, the meanings of scientific publications may also change as time goes by. In other words, the same publication may be cited in distinct contexts. To investigate whether the meanings of citations have changed in different scenarios, which is also called in the semantic shifts in citations, we followed the same ideas of how researchers studied semantic shifts in language. To be more specific, we combined the temporal referencing model and the Word2Vec model to explore the semantic shifts of scientific citations in two aspects: their usages over time and their usages across different domains. By observing how citations themselves changed over time and comparing the closest neighbors of citations, we concluded that the semantics of scientific publications did shift in terms of cosine distances.

Cloud vendors have many data centers around the world and offer in each data center possibilities to rent computational capacities with different prices depending on the needed power and time. Most vendors offer flexible pricing, where prices can change hourly, for instance, Amazon Web Services. According to those vendors, price changes depend highly on the current workload. The more workload, the pricier it is. In detail, this paper is about the offered spot services. To get the most potential out of this flexible pricing, we build a framework with the name ELMIT, which stands for Elastic Migration Tool. ELMIT’s job is to perform price forecasting and eventually perform migrations to cheaper data centers. In the end, we monitored seven spot instances with ELMIT’s help. For three instances no migration was needed, because no other data center was ever cheaper. However, for the other four instances ELMIT performed 38 automatic migrations within around 42 days. Around 160$ were saved. In detail, three out of four instances reduced costs by 14.35%, 4.73% and 39.6%. The fourth performed unnecessary migrations and cost at the end more money due to slight inaccuracies in the predictions. In total, around 50 cents more. Overall, the outcome of ELMIT’s monitoring job is promising. It gives reason to keep developing and improving ELMIT, to increase the outcome even more.

The introductory section of the thesis discusses on the European General Data Protection Regulation, abbreviated GDPR, background information and historical facts. The second section covers basic concepts of personal data and GDPR enforcement. The third section gives detailed analysis on data subject rights as well as best practices for GDPR compliance to avoid penalties. The fourth section concentrates on the technical aspects of the right to be forgotten, solely concentrating on the technical aspects of permanent erasure/deletion of personal or corporate data in compliance with the customer’s desire. Permanent deletion or erasure of data, technically addressing the issue of the right to be forgotten and block chain network technology are the main focus areas of the thesis. The fifth section of the thesis profoundly elaborates block chain and the relation with GDPR compliance in particular. Then the thesis resumes explaining about security aspects and encryption, confidentiality, integrity and availability of data as well as authentication, authorization and auditing mechanisms in relation to the GDPR. The last section of the thesis is the conclusion and recommendation section which briefly summarizes the entire discussion and tries to suggest further improvements

Indoor localization in Smart factories encounters difficult conditions due to metallic environ- ments. Nevertheless, it is one of the enablers for the ongoing industrial revolution, Industry 4.0. This study investigates the usability of indoor localization in a real factory site by tracking hoist assembly process. To test the hypothesis that indoor localization works in a factory environment, an Ultra- Wideband Indoor Positioning System was installed to cover the hoist assembly space. The system followed hoist assembly trolleys for three weeks after which data was analysed by cal- culating assembly times. The results show that indoor localization with Ultra-Wideband technology is a working solution for industrial environments similar to the tested environment. The time calculations are more accurate than known standard times and reveal that hoist assemblies are not standard and there is wasted time. The results suggest that indoor localization is adaptable to industrial environments and to manufacturing processes. Analysing the processes through the position data provides new knowledge that is used for improving the productivity.

Latency is one of the key performance elements affecting the quality of experience (QoE) in computer games. Latency in the context of games can be defined as the time between the user input and the result on the screen. In order for the QoE to be satisfactory the game needs to be able to react fast enough to player input. In networked multiplayer games, latency is composed of network delay and local delays. Some major sources of network delay are queuing delay and head-of-line (HOL) blocking delay. Network delay in the Internet can be even in the order of seconds. In this thesis we discuss what feasible networking solutions exist for browser multiplayer games. We conduct a literature study to analyze the Differentiated Services architecture, some salient Active Queue Management (AQM) algorithms (RED, PIE, CoDel and FQ-CoDel), the Explicit Congestion Notification (ECN) concept and network protocols for web browser (WebSocket, QUIC and WebRTC). RED, PIE and CoDel as single-queue implementations would be sub-optimal for providing low latency to game traffic. FQ-CoDel is a multi-queue AQM and provides flow separation that is able to prevent queue-building bulk transfers from notably hampering latency-sensitive flows. WebRTC Data-Channel seems promising for games since it can be used for sending arbitrary application data and it can avoid HOL blocking. None of the network protocols, however, provide completely satisfactory support for the transport needs of multiplayer games: WebRTC is not designed for client-server connections, QUIC is not designed for traffic patterns typical for multiplayer games and WebSocket would require parallel connections to mitigate the effects of HOL blocking.

The number of IoT and sensor devices is expected to reach 25 billion by 2030. Many IoT appli- cations, such as connected vehicle and smart factory that require high availability, scalability, low latency, and security have appeared in the world. There have been many attempts to use cloud computing for IoT applications, but the mentioned requirements cannot be ensured in cloud environments. To solve this problem, edge computing has appeared in the world. In edge environments, containerization technology is useful to deploy apps with limited resources. In this thesis, two types of high available Kubernetes architecture (2 nodes with an external DB and 3 nodes with embedded DB) were surveyed and implemented using K3s distribution that is suitable for edges. By having a few experiments with the implemented K3s clusters, this thesis shows that the K3s clusters can provide high availability and scalability. We discuss the limitations of the implementations and provide possible solutions too. In addition, we provide the resource usages of each cluster in terms of CPU, RAM, and disk. Both clusters need only less than 10% CPU and about 500MB RAM on average. However, we could see that the 3 nodes cluster with embedded DB uses more resources than the 2 nodes + external DB cluster when changing the status of clusters. Finally, we show that the implemented K3s clusters are suitable for many IoT applications such as connected vehicle and smart factory. If an application that needs high availability and scalability has to be deployed in edge environments, the K3s clusters can provide good solutions to achieve the goals of the applications. The 2 nodes + external DB cluster is suitable for the applications where the amount of data fluctuate often, or where there is a stable connection with the external DB. On the other hand, the 3 nodes cluster will be suitable for the applications that need high availability of the database even in poor internet connection. ACM Computing Classification System (CCS) Computer systems organization → Embedded and cyber-physical systems Human-centered computing → Ubiquitous and mobile computing

The Internet of Things (IoT) aims at linking billions of devices using the internet and other heterogeneous networks to share information. However, the issues of security in IoT environments are more challenging than with ordinary Internet. A vast number of devices are exposed to the attackers, and some of those devices contain sensitive personal and confidential data. For example, the sensitive flows of data such as autonomous vehicles, patient life support devices, traffic data in smart cities are extremely concerned by researchers from the security field. The IoT architecture needs to handle security and privacy requirements such as provision of authentication, access control, privacy and confidentiality. This thesis presents the architecture of IoT and its security issues. Additionally, we introduce the concept of blockchain technology, and the role of blockchain in different security aspects of IoT is discussed through a literature review. In case study of Mirai, we explain how snort and iptables based approach can be used to prevent IoT botnet from finding IoT devices by port scanning.

The business applications such as weather forecasting, traffic management, weather forecasting, traffic management, etc., are enormously adopting Internet of Things(IoT). While scaling of these applications are fast, the device/sensor capabilities, particularly in terms of battery life and energy efficiency is limited. Despite of intensive research conducted to address these shortcomings, Wireless IoT Sensor Network(WIoTSN) still cannot assure 100\% efficient network life. Therefore, the core objective of the thesis is to provide an overview of energy efficiency of proactive(OLSR) and reactive(DSR and AODV) data routing protocols by scaling the size of network, i.e. number of sensor nodes, data packet size, data transmission rate and speed of mobile sink node. It also reviews the importance of security in WIoTSN. The two approaches, such as literature review and simulation testing, are used to achieve the objective of the thesis. The literature review provides information about reactive and proactive protocols and their mechanism for route discovery. Similarly, the network simulator tool NS3 is used for running simulation to evaluate the performance of selected routing protocols for energy efficiency. The thesis results showed the effect of scaling the parameters selected for experimental purpose on the energy efficiency of proactive and reactive data routing protocols. The simulation results prove that the reactive protocol DSR outperforms another reactive protocol AODV and proactive protocol OLSR in energy efficiency. From the security perspective, the thesis also emphasizes its need in IoT and suggest to minimize wasteful resources in WIoTSN and use them by restructuring the network for secure energy-efficient data routing protocols.

Security of web communication is crucial. When accessing an online bank, for example, one of the key issues is that the user can be assured they are communicating with the bank as they intended to. This assurance is achieved with the public key infrastructure for the Web, Web PKI. Its purpose is to manage digital certificates on the Web. Certificates are used to prove one’s identity with the help of public-key cryptography. Certificate authorities and software vendors that operate certificate root stores have key roles in the Web PKI. The first issue certificates and the latter choose which CAs are trusted. The Web PKI has multiple challenges and it is a highly researched topic. Numerous countermeasures and enhancements to the Web PKI have been developed over the years. This thesis investigates challenges in the Web PKI and proposed countermeasures, some of which are based on blockchain technology. Of the non-blockchain-based solutions, we introduce Certificate Transparency, CAA and DANE. Of the blockchain-based solutions, CertLedger, IKP and a solution for decentralising ACME protocol are described. We find that the challenges are mainly related to certificate authorities, revocation and root stores. From the numerous solutions, Certificate Transparency and CAA are utilised in the Web PKI. Shortening the validity period of certificates can resolve some of the challenges. Blockchain-based solutions are numerous but none has yet seen wide deployment.