This master’s thesis deals with architecture of the IMS network and analysis of the affects when loading the network. Architecture of IMS is a network of new generation. It convergates fixed and mobile networks and it enables quick installation of new multimedia services. The first chapter is focused on the description of the IMS architecture, its components and their function. The next chapter is devoted to the main protocols in the IMS system. It is mainly about signalization protocol SIP. The third chapter focuses on the queueing theory. For simulation of the IMS network, Open IMS Core enviroment was chosen, described in the fourth chapter. Next chapter is dedicated to the IMS Bench SIPp tool used for generating and testing the SIP protocol with focus on the IMS. The final chapter dedicates to the realization of an IMS network. The begining of this chapter deals with the description of individual conections generated by the IMS Bench SIPp tool. In the next part load tests focused on the created IMS network are created and analyzed in detail. The end of the chapter describes the implementation of the real finished call between devices and the Android operating system.

This diploma thesis deal with double problematic both engine bed of Jabiru 3000 engine and by overhead container. In both cases the engineering design is solved with compliance of ASTM F2245-04 LSA rules. The structures are shaped by Catia V5R17 software. For calculation of acting forces of bar model of the engine bed Finite Element Method software Patran was used. Strength verification of both engine bed and container was done analytically.

This thesis deals with the conceptual design of a trailer for transportation of Formula car SAE and experimental vehicle Formula Ford. The design of the trailer is presented in the thesis in accordance with the legislation of the Czech Republic. The trailer dimensioning is desinged in view of the anticipated loads. The main task of the thesis is the strength test of the designed trailer.

The aim of this thesis is to develop a load balancing tool for OpenFlow networks. Software-defined networking (SDN) principles are introduced (OpenFlow protocol used as an example) and compared to the legacy routing and switching technology. Openflow is the first protocol/API enabling communication between the control and infrastructure planes of the software-defined networking model. Key features of the protocol are described and several OpenFlow controllers are introduced. Current best practices in computer networks load balancing are discussed as well. The load balancing application development process is described including the test laboratory setups - Mininet (SW) and OFELIA (HW). The application test results are evaluated and possible further enhancements to the program are discussed.

With the growing concerns about energy shortage and demand supply imbalance, demand side management (DSM) activities has found its way into the mining industry. This study analyzes the potential to save energy and energy-costs in underground mine ventilation networks, by application of DSM techniques. Energy saving is achieved by optimally adjusting the speed of the main fan to match the time-varying flow demand in the network, which is known as ventilation on demand (VOD). Further cost saving is achieved by shifting load to off-peak or standard times according to a time of use (TOU) tariff, i.e. finding the optimal mining schedule. The network is modelled using graph theory and Kirchhoff’s laws; which is used to form a non-linear, constrained, optimization problem. The objective of this problem is formulated to minimize the energy cost; and hence it is directly given as a function of the fan speed, which is the control variable. As such, the operating point is found for every change in the fan speed, by incorporating the fan laws and the system curve. The problem is solved using the fmincon solver in Matlab’s optimization toolbox. The model is analyzed for different scenarios, including varying the flow rate requirements and tariff structure. Although the results are preliminary and very case specific, the study suggests that significant energy and energy-cost saving can be achieved in a financially viable manner. / Dissertation (MEng)--University of Pretoria, 2014. / tm2015 / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

Context: In recent years, households have been increasing energy consumption to very high levels, where it is no longer sustainable. There has been a dire need to find a way to use energy more sustainably due to the increase in the usage of energy consumption. One of the main causes of this unsustainable usage of energy consumption is that the user is not much acquainted with the energy consumed by the smart appliances (dishwasher, refrigerator, washing machine etc) in their households. By letting the household users know the energy usage consumed by the smart appliances. For the energy analytics companies, they must analyze the energy consumed by the smart appliances present in a house. To achieve this Kelly et. al. [7] have performed the task of energy disaggregation by using deep neural networks and producing good results. Zhang et. al. [7] has gone even a step further in improving the deep neural networks proposed by Kelly et. al., The task was performed by Non-intrusive load monitoring (NILM) technique. Objectives: The thesis aims to assess the performance of the deep neural networks which are proposed by Kelly et.al. [7], and Zhang et. al. [8]. We use deep neural networks for disaggregation of the dishwasher energy consumption, in the presence of vampire loads such as electric heaters, in a Swedish household setting. We also try to identify the training time of the proposed deep neural networks.  Methods: An intensive literature review is done to identify state-of-the-art deep neural network techniques used for energy disaggregation.  All the experiments are being performed on the dataset provided by the energy analytics company Eliq AB. The data is collected from 4 households in Sweden. All the households consist of vampire loads, an electrical heater, whose power consumption can be seen in the main power sensor. A separate smart plug is used to collect the dishwasher power consumption data. Each algorithm training is done on 2 houses with data provided by all the houses except two, which will be used for testing. The metrics used for analyzing the algorithms are Accuracy, Recall, Precision, Root mean square error (RMSE), and F1 measure. These software metrics would help us identify the best suitable algorithm for the disaggregation of dishwasher energy in our case.  Results: The results from our study have proved that Gated recurrent unit (GRU) performed best when compared to the other neural networks in our study like Simple recurrent neural network (SRN), Convolutional Neural Network (CNN), Long short-Term memory (LSTM) and Recurrent convolution neural network (RCNN). The Accuracy, RMSE and the F1 score of the GRU algorithm are higher when compared with the other algorithms. Also, if the user does not consider F1 score and RMSE as an evaluation metric and considers training time as his or her metric, then Simple recurrent neural network outperforms all the other neural nets with an average training time of 19.34 minutes.

This paper deals with the possibilities for load balancing and clustering of an existing server for speech processing. The paper analyzes problems of load balancing and clustering. There are also described the concepts of network programming and options for I/O processing. A new design of a load balancer is created, fully customized for the needs of speech processing server. This newly designed load balancer is implemented and thoroughly tested.

Background Meetings are important for organisational functioning and the co-ordination of people, tasks and processes, and an everyday reality of organisational life. As mobile communication technology, such as smart phones, tablets and laptops gets smaller and more powerful, these devices have become more pervasive in every aspect of personal and work life. Increasingly, organisations allow mobile devices to be used during meetings in an effort to be more efficient and save time. However, for a meeting to achieve the desired meeting outcomes, those that participate in the meeting need be actively engaged and focused. It is widely accepted though that mobile communication technology is distracting and can easily draw away one’s focus. This begs the question then as to whether employees should in fact be able to use mobile devices in meetings, or not. Rationale for the research study Research into the effect of mobile communication technology as a source of digital distraction on meeting performance, given individual differences in cognitive processing, is limited. Moreover, no experimental studies could be found that have investigated these relationships. It is hoped that the results of the present study will address the gap that was identified in the literature, as well as provide a useful practical contribution for organisations. The findings of the present study may further be used to inform organisation policy and practice concerning the use of mobile communication technology in meetings. Aim of the research study The aim of the present study was to investigate if the presence of digital distraction in meetings, i.e. the presence of mobile communication technology or mobile devices significantly negatively influences selected cognitive processes (i.e. cognitive load and attention conflict) and ultimately meeting performance (assessed as the time it takes to make a decision; as well as the number and quality of decisions made). Research design and method A two-group post-test only, quasi-experimental research method was utilised to investigate the causal effect of the presence of digital distraction on selected aspects of cognitive processing and meeting performance. For an experiment to be valid, no systematic bias should exist in the comparison groups before the manipulation or intervention, otherwise, one would not be able to deduce that any difference that is observed after the manipulation or intervention was due to the manipulation or intervention. Therefore, to ensure that two equivalent treatment groups were available, individuals were randomly assigned to two meetings. The composition of the two groups was then assessed using the demographic variables that were collected and were not found to be significantly different from one another. The average level concentration performance or attentiveness was also measured and not found to be significantly different. This suggests that the average level of distractibility was the same for the two groups. Two equivalent meetings were held with only the availability of mobile communication technology being different between the meetings (i.e. mobile devices were present and used during the meeting or not). After the meetings were concluded, respondents were asked to complete an online questionnaire that consisted of closed- and openended questions designed to measure the concentration performance, cognitive load and attention conflict constructs. Meeting performance was further evaluated by two independent subject matter experts using a decision-rating scale. Sampling and sample As meetings in organisations was the focus, the study targeted employed individuals, a convenient sample of employees were obtained (n=15) that were randomly assigned to one of two participant groups in two separate meetings. Results The inferential data analyses revealed that cognitive load and attention conflict were both statistically significantly higher in the meeting in which the use of mobile devices were available and used, compared to the meeting in which mobile devices were not present. Moreover, it was found that meeting performance was lower in the meetingwhere mobile communication technology was present. The members of the two meetings made a similar number of decisions, which the independent assessors rated as being of similar quality, however, the group in which mobile communication technology was available took 30 per cent longer (120 versus 90 mins) to come to a similar outcome. Findings The results of the present research study suggest that the presence of digital distraction placed significant (additional) demands on the cognitive processing of individuals, who in meetings are required to fulfil cognitive decision-making tasks. As a direct or indirect result, the presence of digital distractions had a marked negative impact on meeting performance and productivity. Based on the findings, it is argued that restricting digital distractions in meetings can greatly reduce the time spent in meetings, while still achieving desired meetings outcomes. Meetings are essential to effective organisational management and coordination but are also resource intensive with managers spending substantial amounts of their available work time in meetings. Organisations operating in resource constrained environments need to be increasingly efficient in their use of scarce resources and, arguably, time is the most precious resource of all. Managerial Implications Based on the findings of the present study, it is recommended that unless mobile communication devices are required to achieve meeting outcomes, managers should declare meetings as technology free zones. Doing so may lead to shorter more productive meetings giving those that often attend meetings more time to attend to other matters.

The development in society means that infrastructure like ballasted railway systems are facing challenges due to request for increased number of high-speed trains and heavier freight trains. This implies that ballasted railways get an increased impact from larger dynamic loads. The question is how the ballasted railways are today affected by dynamic loading and how will an increase in train speed and weight change the soil behaviour within the railway embankment.  A method of investigating dynamic soil behaviour is via geophysical measurements. Accelerometers are commonly used for vibration measurements and by installing them on trains are measurements possible to perform for complete railway sections. The knowledge of expected natural frequencies for various track components and soil layers are essential when considering frequency based analysis of vibration measurements. Thus, a frequency based analysis of accelerometer measurements from track recording coaches enables a possible method for analysing the impact of dynamic loads on underlying soil materials with means of a knowledge of expected natural frequencies for various track components and soil layers. Importance to study frequency content of ground motions became more relevant after the Mexico City earthquake 1985 i.e. studies on this specific earthquake revealed amplification of ground motions due to a long duration of shaking and resonance of soil deposits and furthermore causing damage to buildings whose natural period was the same as the period of ground motion. Thus, if we consider a railway with long train sets running along the railway line. Long durations of shaking of the ground can occur as well as a possible resonance of various soil layers leading to changes in material properties. An interesting finding regarding vibration measurements conducted on a track recording coach show that after Fast Fourier Transformation of the measured vibration data, a frequency spectrum analysis indicate possibilities to detect resonance of the ballast layer in the railway embankment. Therefore, this thesis focus on frequency based analysis of the ballast layer were indications of changes in shear modulus of ballast is seen with means of frequency spectrum and theoretical knowledge of the change in shear modulus in ballast material under cyclic loading and increased shear strain. The thesis consists of two main parts, first is the construction of the so-called frequency-based analysis method of track alignment measurements in a geodynamic perspective and the second part is application of the frequency-based method on a case study. Thus, the scientific contribution of this thesis is to increase knowledge of track alignment measurements in the geotechnical field and to provide a frequency based analysis method of track alignment measurements in a geodynamic perspective for evaluation of soil properties. For the actual case study two different railway sections in Sweden is chosen to enable a comparison, especially when these sections differ with respect to one having only a ballast layer and subgrade and one having ballast, sub ballast and subgrade. Thus, the section with only ballast and subgrade enable a clearer analysis since these layers have large difference in natural frequency. First section is located at Tolikberget in the north part of Sweden and second one between Stenkumla and Dunsjö in south of Sweden. From the analysis of the selected sections it is possible to see indications from the frequency spectrum that the vibration measurements capture the natural frequencies of ballast material associated to the maximum shear modulus and to varying degrees of reduced shear modulus due to increased shear strain. Thus, it can be concluded that vibration measurements conducted on track recording coaches have potential to be used for studies of changes in ballast materials dynamic properties.

On-load tap-changers (OLTC) are devices in the power grid that keeps the voltage level constant for consumers, regardless of the power demand. Hitachi ABB Power Grids, producer of the OLTC family named VUC, guarantees 30 years of lifetime. Such a pledge requires high standard devices. This thesis has analyzed data from routine tests of switching times in the diverter switch of OLTC’s, performed before devices were put in service. The correlation of part switching times for all units leaving the factory during the past year was evaluated by calculating Pearson’s correlation coefficient. A linear trend was fitted to the data, realizing that the prediction errors, as well as the part switching times, were Gaussian distributed. The time while the resistor vacuum interrupter was open could be predicted within the interval of approximately 2ms with 2 standard deviations accuracy. To classify time series from the routine test as expected or unexpected, a model-based algorithm was implemented. The average switching time for all consecutive switches was used to define expected series. A moving average was implemented to neglect outliers and remove oscillating patterns. The majority of all data was classified as expected time series. The ones who did not, still preserved a good correlation between the part switching times. Examining the relationship between part switching times could be a valuable perspective in further classification of expected time series. The possibility of incorporating measurement of part switching times on OLTC’s in normal operation, to use the knowledge gained by this thesis, was investigated. Position sensors were mounted to measure the position of the lifting yokes, opening and closing the vacuum interrupters. The time while the vacuum interrupter contacts were open could be estimated with better accuracy than the position sensor provided. Unfortunately, those sensors cannot be utilized in normal operation. If other possibilities could be found, perhaps a laser position sensor, the implemented algorithm would be valuable.