This thesis is focused on the issue of reaction time of those people who are affected by alcohol. The thesis is divided into two main parts, the first part is focused on the research of the present state and it submits the theoretical background related to the topic of this thesis. The second part describes both the experiments related to the reaction time of the people affected by alcohol and the evaluation of the results of such measurements.

This diploma thesis deals with the perception of the speed of the vehicle from the point of view of the driver without the possibility of checking the speedometer. The theoretical part is devoted to the driver as a risk factor and vehicle research. The practical part consists of conducted driving tests concerning the subjective perception of the driver according to age, experience and type of vehicle.

The dissertation thesis focuses on the problem of driver inattention as one of the main factors contributing to the traffic accidents occurrence. The importance of this topic has been introduce on the basis of the literature review. The theoretical analysis includes terminology in the field of accident analysis related to the topic of this dissertation thesis. Existing methods for driver behavior analysis have been introduced as well as the selected resuls of existing research studies focused on the driver inattention. Research gaps have been identified on the basis of the research review, on some of them has been focused this work. The defined problem situation points to the need to find and verify the relevant modern methods for analysis of driver inattention, respectivaly influence of selected distracting stimuli on the stages of driver information processing. The series of measurements also provides quantified data, especially with regard to the perception duration of selected distracting stimuli.

The aim of this diploma thesis is to design two different switching power supply circuits with integrated circuits suitable for controlling of LED. The theoretical part describes the principles of two main switching converters topologies – buck and boost. Furthermore, a universal H-bridge structure of switching supply is described. This is compared with the typical switching supply design. Based on specified requirements, two circuits are designed with selected IO which are suitable for using in the automotive industry. Their function and typical schema are described. In the practical part is realized design with both selected IC, choosing components and layout PCB. Set of tests are carried out with manufactured samples. Based on measured results are performed optimalization of samples, which are tested also. In the end of this thesis both samples are compared in terms of function, efficiency and EMC.

The diploma thesis deal with what ways drivers react to an unexpected stimulus. In the theoretical part, the analysis of the current state, reaction time, methods of reaction of the driver, stimuli from the environment and finally is being analyzed, the vehicle and its assistance systems. The analytical part of the diploma thesis was performed by driving tests, where it was found that the way the driver reacts from the distance to which they are obstructed and the speed of the vehicle. For that reason, a TTC dependency analysis was performed. It was found that drivers at low TTC values chose an obstacle in which they brake the need to move their foot from the accelerator pedal to the brake pedal and they have to brake sharply. At medium TTC values, drivers brake most often. In the case of a combination of conductors, they chose braking with avoiding at lower TTC values and avoiding with braking at medium TTC values. There was also a dependence of the method of reaction on driving experience. Inexperienced drivers rather choose braking, experienced drivers use combinations.

Bakgrund: Nattarbete utgör en hälsorisk ur flera aspekter och har flera konsekvenser liknande de som ohälsosamma matvanor har. Bland lastbilschaufförer förekommer långa körningar där hälsosamma matvanor inte främjas. När arbetet sker under natten förskjuts sömnen och enligt dygnsrytmen infaller en naturlig trötthet vilket kan orsaka problem i form av olyckor. Dygnsrytmen styr även hunger och ämnesomsättning. Syfte: Att undersöka arbetsmåltider och det möjliga sambandet med upplevd trötthet hos lastbilschaufförer under både dagkörningar och nattkörningar. Metod: En webbaserad enkät delades ut på ett företag samt i en Facebookgrupp och besvarades av 43 lastbilschaufförer. Resultat: Resultaten visade att det var kaffe, vatten, smörgåsar och sötsaker som intogs i högst utsträckning. Majoriteten av måltider intogs i lastbilen under körning och under nattkörningen intogs måltider främst vid kl. 20 samt 02. För att motverka trötthet intogs koffein. Samband visade att den upplevda tröttheten ökade när intaget av mat och dryck i lastbilen under körning ökade. Samband visade också att den upplevda tröttheten ökade när intag av mat och dryck vid kl. 00-02 minskade. Ytterligare samband visade att den upplevda tröttheten ökade när möjligheten att själv kunna bestämma tid för mat och dryck minskade. Slutsats: Chaufförers möjligheter att lämna lastbilen samt att själv välja när de vill äta och dricka är relevant att förbättra då det finns ett samband mellan detta och den trötthet chaufförerna upplever under sina körningar, både under dag och natt. Arbetsgivare har möjlighet att utforma arbetsorganisationen så att förbättringar kan underlättas. / Aim: To investigate work meals and the possible correlation to sleepiness among truck drivers during both day driving and night driving. Method: A web-based survey was distributed at a company and in a Facebook group. 43 truck drivers responded. Results: The results showed that the most common intake was coffee, water, sandwiches, and sweets. Most of the foods and drinks were consumed inside the truck, while driving. During the night drive foods and drinks were consumed mostly at 8 pm and 2 am. Caffeine was used to counteract sleepiness. Self-reported sleepiness increased as eating or drinking inside the truck, while driving, increased. Sleepiness also increased as eating or drinking at 12 pm-2 am decreased. Another association showed that sleepiness increased as having the option to choose when to eat or drink decreased.  Conclusion: Because of the associations found, it is highly relevant to improve truck driver’s opportunities to leave the truck and to have better options in choosing when to eat or drink. Employers have the possibility to make organisational changes to make improvements easier.

Driver sleepiness is a cause for crashes and it is estimated that 3.9 to 33 % of all crashes might be related to sleepiness at the wheel. It is desirable to get an objective measurement of driver sleepiness for reduced sensitivity to subjective variations. Using deep learning for classification of driver sleepiness could be a step toward this objective. In this master thesis, deep learning was used for investigating classification of electrophysiological data, electroencephalogram (EEG) and electrooculogram (EOG), from drivers into levels of sleepiness. The EOG reflects eye position and EEG reflects brain activity. Initially, the intention was to include electrocardiogram (ECG), which reflects heart activity, in the research but this data were later excluded. Both raw time series data and data transformed into time-frequency domain representations were fed into the developed neural networks and for comparison manually extracted features were used in a shallow neural network architecture. Investigation of using EOG and EEG data separately as input was performed as well as a combination as input. The data were labeled using the Karolinska Sleepiness Scale, and the scale was divided into two labels "fatigue" and "alert" for binary classification or in five labels for comparison of classification and regression. The effect of example length was investigated using 150 seconds, 60 seconds and 30 seconds data. Different variations of the main network architecture were used depending on the data representation and the best result was given when using a combination of a convolutional neural network (CNN) and a long short-term memory (LSTM) network with time distributed 150 seconds EOG data as input. The accuracy was in this case 80.4 % and the majority of both alert and fatigue epochs were classified correctly with 85.7 % and 66.7 % respectively. Using the optimal threshold from the created receiver operating characteristics (ROC) curve resulted in a more balanced classifier with 76.3 % correctly classified alert examples and 79.2 % correctly classified fatigue examples. The results from the EEG data, both in terms of accuracy and distribution of correctly classified examples, were shown to be less promising compared to EOG data. Combining EOG and EEG signals was shown to slightly increase the proportion of correctly classified fatigue examples. However, more promising results were obtained when balancing the classifier for solely EOG signals. The overall result from this project shows that there are patterns in the data connected to sleepiness that the neural network can find which makes further work on applying deep learning to the area of driver sleepiness interesting.

This thesis firstly consists of an analysis and a description of materials suitable for construction of loudspeaker enclosures and a design of the loudspeaker system with the enclosure made of a synthetic stone. Electro – acoustics drivers have been described with a focus to a frequency range, a principle and a construction for an explanation of their function. Drivers based on electrodynamic principle have been described closely. An analysis of materials used for the loudspeaker enclosure production has been done and tradicional and alternative materials have been described as well. Specific modulus, density and stiffness have been taken as an objective evaluative criterion. An evaluation indicates appropriate properties of plastic, aluminum and stone based materials. The function and kinds of loudspeaker enclosures have been described. The function, properties and design of a vented box loudspeaker system have been described closely. The last part of this thesis is individual design of a two-way vented box loudspeaker system with the enclosure made of synthetic stone. A simulation of a driver behavior built in the enclosure and compensation circuits and crossovers design and simulation have been done. The enclosure has been designed with high stress to minimize negative effect of the enclosure to the final sound quality.

The first part of this work describes the design and implementation of switch-mode power supply for control circuits for 12/2x24V 4.5A fuel cells. The introduction picks the issue of power sources in electromobiles and final design and implementation of switching power suply. The next part deals with the issues of fast-charger and generators for power transistors. It describes the structure of DC converter and control and protectin circuits of quick-charger. In the end this work describes selected driver circuits and charge tests on fast-charger as evidenced by measurements.

This project deals with transistorized converters in particular a four-quadrant bridge. The main part of project discusses the drivers of transistors and a possible way of controlling a converter. The proposal of control electronics and the regulation structure are involved in the second part. This project also includes a construction of an apparatus which will be used as a teaching material.