This thesis explores a web-based method to do studies in cultural evolution. Cumulative cultural evolution (CCE) is defined as social learning that allows for the accumulation of changes over time where successful modifications are maintained until additional change is introduced. In the past few decades, many interdisciplinary studies were conducted on cultural evolution. However, until recently most of those studies were limited to lab experiments. This thesis aims to address the limitations of the experimental methods by replicating a lab-based experiment online. A web-based application was developed and used for replicating an experiment on conformity by Solomon Asch [1951]. The developed application engages participants in an optical illusion test within different groups of social influence. The major finding of the study reveals that conformity increases on trials with higher social influence. In addition, it was also found that when the task becomes more difficult, the subject's conformity increases. These findings were also reported in the original experiment. The results of the study showed that lab-based experiments in cultural evolution studies can be replicated over the web with quantitatively similar results.

The field of social network analysis has expanded from the field of social science to the fields of human factors and ergonomics. There is a theory that suggest that one can use the social network methods and create an information network which describes the network from an information sharing perspective and and there are also theories which describes how social network analysis can be used study cognitive maps (mental models). This thesis touches both of these subjects in an attempt to investigate how social network analysis can be used together with real-time information as a data source to investigate the cognitive maps of individuals and comparing these maps with an organisations expected structure based on protocols. The study conducted showed that it was indeed possible to change the social network analysis method into an information based network which explains the origin of a mental model and to study information be- haviour, in a network, but there are still variables which needs to be studied further (e.g. failed information sharing and temporal aspects of information sharing).

As the web browser becomes an increasingly powerful tool for the average web user, with more features and capabilities being developed constantly, the necessity to determine which features perform better than others in the same area becomes more important. This thesis investigates the performance of three separate technologies used to achieve full-duplex real time communication over the web: short polling using Ajax, server-sent events and the WebSocket protocol. An experiment was conducted measuring the performance over three custom-built web applications (one per technology being tested), comparing latency and number of HTTP requests over 100 messages being sent through the application. Additionally, the latency measurements were made over three separate network conditions. The experiment results suggest the WebSocket protocol outperforms both short polling using Ajax and server-sent events by large margins, varying slightly depending on network conditions.

As the web browser becomes an increasingly powerful tool for the average web user, with more features and capabilities being developed constantly, the necessity to determine which features perform better than others in the same area becomes more important. This thesis investigates the performance of three separate technologies used to achieve full-duplex real time communication over the web: short polling using Ajax, server-sent events and the WebSocket protocol. An experiment was conducted measuring the performance over three custom-built web applications (one per technology being tested), comparing latency and number of HTTP requests over 100 messages being sent through the application. Additionally, the latency measurements were made over three separate network conditions. The experiment results suggest the WebSocket protocol outperforms both short polling using Ajax and server-sent events by large margins, varying slightly depending on network conditions.

The goal of this diploma thesis is to design and implement a mobile application for home security system on the iOS platform. The application introduces a complex solution allowing the transmission of the audio and video streams between the paired mobile devices using WebRTC. The final module represents universal solution for peer-to-peer audio and video communication. The thesis also deals with the field of computer vision, namely efficient motion detection algorithms. The module for motion detection implements ViBe algorithm using Metal. In case that the motion is detected the application notifies a user with a push notification. Synchronization of application data is implemented using Cloudkit and the data persistance using Realm library.

The demands of a modern way of life have changed the way power electronics systems work. For instance, the grid has to provide not only the service of delivering electrical energy but also the communication to enable interactions between customers and enable them to be producers of electrical energy, too. Thus, the smart grid has come into existence. The consequence of the smart grid is that consumers could be “smart.” The most obvious consumers are households, so the houses have to also be smart and must be equipped with various power electronics devices for producing and managing electrical energy. Again, all those devices have to communicate somehow and provide data for managing electrical energy in the house. Zoomed in further, novel, state-of-the-art measurement equipment could have been built from different power electronics devices, and communication among them would be necessary for good operation. Zoomed further in, communication among different pieces of power electronics devices (such as converters) could offer benefits such as flexibility, abstraction, and modularity. This thesis provides insight into different communication techniques and protocols used in power electronics systems. A top-down approach presents three different levels of communication used in real-life projects with all the challenges they bring, starting with the smart house, followed by the state-of-the-art impedance measurement unit, and finalizing with internal power electronics building block (PEBB) communication. In the case of a smart house, where the house is equipped with solar panels, charge controllers, batteries, and inverters, communication allows interoperation between different elements of the power electronics system, enabling energy management. Results show the operation of the system and energy management algorithm. A house of this type won first prize at an international competition where energy management was one of the disciplines. The impedance measurement unit consists of different power electronics devices. In this case, too, communication between devices enables the operation of the impedance measurement unit. Communication techniques used here are shown together with measurement results. Finally, inter-PEBB communication has been shown as an approach for interaction among the different elements inside the PEBB, such as controller, GDs, sensors, and actuators. Real-time communication protocol, including all challenges, is described and developed. This approach is shown to enable communication and synchronization among different nodes inside the PEBB. Communication enables all internal elements of the PEBB to be transparent outside the PEBB in the sense that data gathered from them could be reused anywhere else in the system. Also, this approach enables the development of distributed event (time) driven control, hardware and software, abstraction, high modularity, and flexibility. A very important aspect of inter-PEBB communication is synchronization. A simple technique of sharing a clock among the parts of a 6 kV PEBB has been shown. / M.S. / This thesis provides insight into different communication techniques and protocols used in power electronics systems. A top-down approach presents three different levels of communication used in real-life projects with all the challenges they bring, starting with the smart house and a custom device designed and developed to be a communication interface among different power electronics devices from different vendors, such as charge controllers or inverters, but with capabilities not only to communicate but to also provide a platform for the development of energy management algorithms used to make houses grid zero if not grid positive. Aside from the smart house, this thesis describes communication protocols and techniques used in the impedance measurement unit (IMU). This complex measurement device provides valuable and accurate impedance measurements and consists of different power electronics devices that need to communicate. Finally, at the power electronics building block (PEBB) level, real-time communication protocol with all challenges is described. Developed communication protocol provides communication and synchronization among different nodes such as GDs, sensors, and actuators inside the PEBB. This intra-PEBB communication and synchronization combined with inter-PEBB communication and synchronization provide the foundation for the development of truly distributed event- (time-) driven control as well as hardware and software abstraction.

The subject of this thesis is the design and implementation of a client-server applications for collecting GPS data using a smartphone with Android OS. The system is used for real-time monitoring and recording vehicle’s movement on a server, where the data are adapted to the real road. This thesis is a continuation of the project DoAutoškoly.cz . The theoretical part of the thesis deals with GPS, real-time communication problems and the Android platform, including its application interface for GPS. In the next part of the thesis, this knowledge is used to design the whole system. The thesis continues with the implementation of a mobile application, the web module and the corresponding server application. The chapters continue to deal with real-time tracking and route editing. The last part is focused on testing and evaluation of the results.

In real-time systems spanning a network, there is a need for deterministic communication. The best-effort approach which most of the Internets traffic follows is not suitable for this area since it does not guarantee packet delivery within a deadline and there is also no accurate measure of when the packet was sent. The network core and edge entities such as routers and hosts do not have any concept of time in normal networking, making real-time constraints more difficult to enforce. Time Sensitive Networking is a set of standards, all of which are related to solving the problem above. The most central of these standards is IEEE 802.1AS which defines the generic Precision Time Protocol that specifies how all the nodes of a network should synchronize their clocks to one master clock, giving them a common perception of time. This standard is a prerequisite for some of the other standards in the suite, for example, the 802.1Qbv standard defining a Time Aware Sharper which provides bounded latency for time-critical traffic. A common perception of time is also by itself needed by applications that have to orchestrate actions, with temporal relations to each other, across a network. These applications can be found within areas such as industrial automation and vehicular control systems. The problem that this thesis explores is how the precision of time synchronization of a Time Sensitive Networking (TSN) solution depends on variables in the network such as configuration, topology, and external factors. To find the correlation between the parameters and the precision of the time synchronization, several experiments have been conducted. The experiments were performed on a simple network of hardware components constituting a physical test bed and an oscilloscope was used to probe the clocks if its nodes and extract measurements. Our findings indicate several relationships between the tested parameters and the synchronization precision. The biggest conclusion we can make from our study is that the IEEE 802.1AS standard does not rely on the support of other standards to achieve sub-microsecond results when there is a best-effort traffic load on the network. The manipulated configuration of the standard has given results that in general coincide with the expected behavior. Finally, the data gathered on different topologies, that were tested showed no significant trends regarding the precision. / I realtidssystem som kommunicerar över nätverk finns det ett behov av deterministisk kommunikation. Det vanliga tillvägagångssättet som de mesta av internettrafiken följer är inte lämpligt för detta område eftersom det inte garanterar paketleverans inom en deadline och det inte heller finns något exakt mått av när paketet skickades. Nätverkets enheter som routrar och noder har inte någon uppfattning om tid i normala nätverk, vilket gör realtidsbegränsningar omöjliga att upprätthålla. Time Sensitive Networking är en uppsättning standarder, som alla är relaterade till att lösa problemet ovan. Den mest centrala av dessa standarder är IEEE 802.1AS som definierar generic precision Time Protocol som specificerar hur alla noder i ett nätverk ska synkronisera sina klockor till en masterklicka, vilket ger dem en gemensam tidsuppfattning. Denna standard är en förutsättning för några av de andra standarderna i sviten, till exempel 802.1Qbv-standrarden som definierar en Time Aware Scheduler som ger begränsad latens för tidskritisk trafik. En gemensam tidsuppfattning behövs också av applikationer som måste orkestrera operationer, med tidsmässiga relationer till varandra, över ett nätverk. Dessa applikationer finns inom områden som industriell automation och fordonsstyrningssystem. Problemet som denna avhandling undersöker är hur precisionen av tidssynkronisering av en TSN-lösning beror på variabler i nätverket så som konfiguration, topologi och externa faktorer. För att hitta korrelationen mellan parametrarna och precisionen i tidssynkroniseringen har flera experiment genomförts. Experimenten utfördes på ett enkelt nätverk av hårdvarukomponenter som utgör en fysisk testbädd och ett oscilloskop användes för att undersöka klockorna på dess noder och extrahera mätningarna. Våra resultat indikerar flera samband mellan de testade parametrarna och synkroniseringsprecisionen. Den största slutsatsen vi kan dra från vår studie är att IEEE 802.1AS-standaden inte förlitar sig på stöd från andra standarder för att uppnå resultat under mikrosekunder när det finns en annan trafikbelastning på nätverket. Den manipulerade konfigurationen av standarden har gett resultat som i allmänhet överensstämmer med det förväntade beteendet. Slutligen visade de insamlade data om olika typologier som testades inga signifikanta trender vad gäller precisionen.

When designing architectures and protocols for data traffic requiring real-time services, one of the major design goals is to guarantee that traffic deadlines can be met. However, many real-time applications also have additional requirements such as high throughput, high reliability, or energy efficiency. High-performance embedded systems communicating heterogeneous traffic with high bandwidth and strict timing requirements are in need of more efficient communication solutions, while wireless industrial applications, communicating control data, require support of reliability and guarantees of real-time predictability at the same time. To meet the requirements of high-performance embedded systems, this thesis work proposes two multi-wavelength high-speed passive optical networks. To enable reliable wireless industrial communications, a framework in­corporating carefully scheduled retransmissions is developed. All solutions are based on a single-hop star topology, predictable Medium Access Control algorithms and Earliest Deadline First scheduling, centrally controlled by a master node. Further, real-time schedulability analysis is used as admission control policy to provide delay guarantees for hard real-time traffic. For high-performance embedded systems an optical star network with an Arrayed Waveguide Grating placed in the centre is suggested. The design combines spatial wavelength re­use with fixed-tuned and tuneable transceivers in the end nodes, enabling simultaneous transmis­sion of both control and data traffic. This, in turn, permits efficient support of heterogeneous traf­fic with both hard and soft real-time constraints. By analyzing traffic dependencies in this mul­tichannel network, and adapting the real-time schedulability analysis to incorporate these traffic dependencies, a considerable increase of the possible guaranteed throughput for hard real-time traffic can be obtained. Most industrial applications require using existing standards such as IEEE 802.11 or IEEE 802.15.4 for interoperability and cost efficiency. However, these standards do not provide predict­able channel access, and thus real-time guarantees cannot be given. A framework is therefore de­veloped, combining transport layer retransmissions with real-time analysis admission control, which has been adapted to consider retransmissions. It can be placed on top of many underlying communication technologies, exemplified in our work by the two aforementioned wireless stan­dards. To enable a higher data rate than pure IEEE 802.15.4, but still maintaining its energy saving properties, two multichannel network architectures based on IEEE 802.15.4 and encompassing the framework are designed. The proposed architectures are evaluated in terms of reliability, utiliza­tion, delay, complexity, scalability and energy efficiency and it is concluded that performance is enhanced through redundancy in the time and frequency domains.

With the upsurge in the demand for high-bandwidth networked real-time applications in cost-sensitive environments, a key issue is to take advantage of developments of commodity components that offer a multiple of the throughput of classical real-time solutions. It was the starting hypothesis of this dissertation that with fine grained traffic shaping as the only means of node cooperation, it should be possible to achieve lower guaranteed delays and higher bandwidth utilization than with traditional approaches, even though Switched Ethernet does not support policing in the switches as other network architectures do. This thesis presents the application of traffic shaping to Switched Ethernet and validates the hypothesis. It shows, both theoretically and practically, how commodity Switched Ethernet technology can be used for low-latency hard real-time communication, and what operating-system support is needed for an efficient implementation.