This paper presents the health chatbot application created on the Chatfuel platform. This application allows people to interact with the health chatbot in the same way as they do with other people. The health chatbot identifies their symptoms through a series of queries and guides them to decide whether or not to go to doctor. Such application can be of great benefit to people who are not sure whether their symptoms are transients or require a response to a doctor for detailed tests. It also offers advice to users on minor illnesses, and in that way, encourages people to take appropriate measures to stay healthy, which is a great example of promoting a healthy life. For the purpose of this research, an end-user survey was created and conducted with aim to collect the users’ opinion regarding the acceptance and usage motivation of health chatbot. The results showed good acceptance and usage motivation of health chatbot.

Under normal conditions it may take years to gather failure data on the life cycle of new LED products. Through accelerated life testing the product life of HP LED is simulated by increasing the stress levels of the ambient temperature to higher than normal. A lifetime acceleration estimate is made using the Arrhenius model. The value of activation energy is not assumed, but is experimentally determined by performing tests at multiple temperatures and plotting the results. The acceleration factor is obtained by the ratio of the reaction rates at the tested temperatures and the declared temperature. Using the correct value of the activation energy is important because it represents the dominating reason for degradation and small change in its value will have an effect on the acceleration factor.Under normal conditions it may take years to gather failure data on the life cycle of new LED products. Through accelerated life testing the product life of HP LED is simulated by increasing the stress levels of the ambient temperature to higher than normal. A lifetime acceleration estimate is made using the Arrhenius model. The value of activation energy is not assumed, but is experimentally determined by performing tests at multiple temperatures and plotting the results. The acceleration factor is obtained by the ratio of the reaction rates at the tested temperatures and the declared temperature. Using the correct value of the activation energy is important because it represents the dominating reason for degradation and small change in its value will have an effect on the acceleration factor.

– The performed evaluation consisted of two phases: measurement of the illumination levels of (new) LED system and carrying out the public opinion poll on the subjective visual performance of LED in traffic lights. The results of the measured levels of illumination show that deposition of dirt considerably affects its values. The survey results confirm an overall positive impression on LED performances in traffic lights.

For long life light sources, such as Light Emitting Diodes (LED), evaluation and performance testing at nominal values is not a practical approach. Since it can take years to determine the life it is necessary to use methods of accelerated life testing. The effect of temperature on degradation of radiant flux GaN based High Power (HP) LED is monitored on two groups of commercial samples. The degradation is accelerated by increased values of pin temperatures. For the first test group, the degradation of radiant flux has exponential nature for all test temperatures, but for the second test group no degradation of flux is observed within the measured interval. This occurrence implies that is likely that different brands of HP LEDS have diverse heat extraction mechanisms from the LED junction.

High power light emitting diodes (HP LED) are energy efficient light sources that have been developing at great speed. Aging process was performed at increased pin temperatures, with approximate values of 80°C, 90°C and 100°C and constant current. The conditions in chambers are simultaneously monitored for approximately 5000 hours. The change in HP LED's SPD was small and for the second test group was within the narrower wavelength interval than for the first. This interval corresponds to the phosphor emission region and indicates that important factor of white LED's SPD stability is the choice of type of phosphor used.

Although fluorescent lighting is considerably more efficient then incandescent, and is in wide use, manufacturers find new ways to improve its configuration and reduce energy use. Based on the fundamentals of “Non‐imaging Optics”, was experimentally investigated the dependence of illumination of a point in the space on the distance between the reflection and fluorescent light source. Monitoring of changes in illumination is performed by optical sensor and corresponding computer software. Investigation of the influence of the distance between the fluorescent light and the reflector on the relative illumination has shown, for the tested geometries, that by reducing the distance between them the illumination increased, even though the distance among the source and the measuring point got greater.

In this paper the interface trap densities (D/sub it/) of 6H- and 4H-SiC MOSFETs in the subthreshold region have been studied. Interface trap densities in this region were extracted as a function of trap energy (E/sub T/) from the transfer characteristics. We show these interface trap densities increase exponentially approaching the onset of strong inversion for both polytypes, and D/sub it/(E/sub T/) is higher in 4H than in 6H through the subthreshold region. These results are consistent with previous reports.