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Minimum resolvable temperature difference (MRTD) is considered as the most important parameter of thermal imagers. A new method of MRTD measurement without drawbacks of other methods is presented in this paper. Proposed MRTD measurement method coded as virtual MRTD is based on a three steps measurement concept using semi-automatic objective measurements and computer simulation. First, objective parameters of the tested thermal imager are measured. Second, software simulates this tested thermal imager and generates the image of 4-bar target of specified spatial frequency (size) and contrast (temperature difference). Third, a human observer analyses the images of the 4-bar target generated by the software on the screen of PC set and measures MRTD of the simulated thermal imager at specified set of spatial frequencies. The proposed method offers higher measurement speed, lower cost and typically better accuracy in comparison with the typical MRTD measurement method.

The profile of deep magnetotelluric sounding (MT) from Duc Trong - Tuy Phong has been carried out in Lam Dong and Binh Thuan provinces. The length of the Duc Trong - Tuy Phong profile is about 80 km with 15 stations and the distance between the stations measures about 5 km. Two-dimensional MT inversion was used to find a resistivity model that fits the data. The 2D resistivity model allows determining position and development formation of the Nha Trang - Tanh Linh fault. This is the deep fault, which is showed by the boundaries of remarkable change of resistivity. In the near surface of the Earth (from ground to the depth of 6 km), the angle of inclination of this fault is about 60o; in the next part, the direction of the Nha Trang - Tanh Linh faut is vertical. Geoelectrical section of the Nha Trang - Tanh Linh profile shows that the resistivity of mid-crust is higher than that of lower-crust and of upper-crust.

Electrical insulation plays an important role in the proper functioning of high voltage power system equipment/components. Examining the condition of insulation is crucial to keep the equipment safe and functioning efficiently. High voltage diagnostic tests, in particular partial discharge measurements, are very effective in detecting early signs of insulation damage. This type of diagnostic test is generally conducted at the power frequency to emulate normal operating condition. However, it is difficult to perform the test on-site due to the large reactive power required when testing high-capacitance objects such as cables. An alternative approach is to conduct the test at very low frequency excitation, commonly at 0.1 Hz, because the required power is proportional to the applied frequency and thus is significantly reduced. However, partial discharge behaviour varies with frequency and thus existing knowledge on interpretations of partial discharge at power frequency cannot be directly applied to test results measured at very low frequency for insulation diagnosis. The motivation of this research is to study partial discharge behaviours at very low frequency and search for physical explanations of such differences. Therefore, this thesis explains those differences in two types of partial discharge, corona discharge and internal discharge, based on extensive experimental measurements and computer simulation. Partial discharge patterns were obtained and analysed using the phase-resolved partial discharge technique. A comprehensive study of corona discharges at different applied voltage waveforms, such as sinusoidal wave and square wave, was carried out under the excitation of very low frequency. Experimental results showed that the inception voltage of corona discharges at very low frequency is dependent on applied voltage waveforms. Furthermore, effects of ambient air on corona discharges were investigated thoroughly at temperatures between 20C and 40C at very low frequency excitation and power frequency for comparison purposes. Measured corona discharge characteristics showed that the increase of ambient temperature results in larger discharge magnitude and causes corona discharges to occur earlier in the phase of the voltage cycle. This research also investigated internal discharge behaviour in a cavity at very low frequency using measurement and simulation. Measurement results showed that partial discharge characteristics are strongly dependent on applied frequency. A dynamic model for numerical computation was developed to study this dependence. The advantage of this model is that it has minimum adjustable parameters to simulate discharges in the cavity. These values were determined using a trial and error approach to fit the simulation results with measured data. Simulation results showed that charge decay has a significant contribution to discharge characteristics at very low frequency. Charge decay causes a reduction of the initial electron generation rate which results in lower discharge magnitude and repetition rate. Also, the statistical time lag of discharge activities was calculated and found exhibiting a great dependence on applied frequency. All in all, the major contribution of this thesis is the development of a dynamic model to characterise physical processes of partial discharge in a cavity. It enables determination of key parameters influencing partial discharge behaviour such as the statistical time lag and the charge decay time constant at different applied frequencies. Moreover, differences in partial discharge characteristics at very low frequency and power frequency as a function of cavity size, voltage waveforms and ambient temperatures are discussed and explained in detail. The findings from this research provide better understanding of discharge behaviours at very low frequency excitation.

In this paper, we propose an extended navigation framework for autonomous mobile robots in dynamic environments using a reinforcement learning algorithm. The main idea of the proposed algorithm is to provide the mobile robots the relative position and motion of the surrounding objects to the robots, and the safety constraints such as minimum distance from the robots to the obstacles, and a learning model. We then distribute the mobile robots into a dynamic environment. The mobile robots will automatically learn to adapt to the environment by their own experienced through the trial-and-error interaction with the surrounding environment. When the learning phase is completed, the mobile robots equipped with our proposed framework are able to navigate autonomously and safely in the dynamic environment. The simulation results in a simulated environment shows that, our proposed navigation framework is capable of driving the mobile robots to avoid dynamic obstacles and catch up dynamic targets, providing the safety for the surrounding objects and the mobile robots.

This bachelor thesis investigates the impact of South China Sea dispute on mutual relations between China and Socialist Republic of Vietnam. Thesis lays great emphasis on the analysis of mutual trading relations. The goal of this work is to find out if the dispute over territory has negative influence on mutual relations and to what extent. Therefore, thesis is divided into 3 main chapters. The introductory chapter describes position and development of each country. Second chapter uses findings from the introductory part for the analysis of political and trade relations of both countries. It focuses on the history of mutual relations and mainly it lays emphasis on current mutual relations. Last chapter of the thesis is dedicated to the issues regarding South China Sea. Motives and causes of this dispute are described in this chapter. It provides a view on the course of this territorial dispute, and also impacts on mutual relations are analyzed. The output of all three chapters helps to formulate following conclusion. Dispute over South China Sea has impact on mutual relations. Predominantly, it influences political relations between China and Vietnam, therefore, this dispute is often mentioned in media. However, according to available data this dispute has not had major effect on trading relations. Mutual trading between both countries went off in dispute period without any limitations and barriers.

Psoriasis is a chronic autoimmune disease in dermatology. The experiment collected peripheral blood samples from cohorts. These samples were treated and sorted mononuclear leukocytes with LPS receptors or CD14. Then, they were stimulated by a lysis of Streptococcus pneumonia in 24 hours. These cells were harvested in 0, 1, 24, 48, 72,120 (day 5) and 168 (day 7) hours and were isolated total mRNA. All mRNA samples were converted into the cDNA samples which were utilised to indirectly evaluate the cytokine expression of TNF-α, IL10 and Heparin-binding EGF-like growth factor (HBEGF) on the mononuclear cells (CD14+) in the period shown. Regarding result of the psoriatic patient, three cytokines abnormally prolonged after the 24 hours induction. The signals of TNF-α, IL10 and HBEGF expanded throughout 48 hours,5 days and 7 days, respectively. In addition, a band (627bp) was obtained in from PCR products of IL10. Furthermore, sequencing the 627bp band shows that it was homologous to a fragment on chromosome 2. Meanwhile, the results of those cytokines on a cohort without non-psoriasis were slightly exposed in around 48 hours. In conclusion, the mononuclear cells (CD14+) in the cohort with guttate psoriasis is highly more sensitive with a lysis of Streptococcus pneumonia than the non-psoriatic cohort in TNF-α expression, and IL10 and HBEGF of the psoriatic one are also simultaneous and extended during the inflammation and wound healing. Furthermore, the 620bp band might relate to edit progressing pre-mRNA IL10 in the guttate psoriasis.