Mobile devices have become an integral part of our life and provide dozens of useful services to their users. However, usability of mobile devices is hindered by battery lifetime. Energy conservation can extend battery lifetime, however, any energy management policy requires accurate prediction of energy consumption, which is impossible without reliable energy measurement and estimation methods and tools. We present an analysis of the energy measurement methodologies and describe the implementations of the internal (profiling) software (proprietary, custom) and external software-based (Java API, Sensor API, GSM AT) energy measurement methodologies. The methods are applied to measure energy consumption on a variety of mobile devices (laptop PC, PDA, smart phone). A case study of measuring energy consumption on a mobile computer using 3DMark06 benchmarking software is presented
This article presents a system of precise navigation for a visually impaired person which uses GPS navigation and an infrared sensor in the form of an infrared matrix. The presented system allows determining the orientation and distance of a blind person relative to a selected object, e.g. a wall or road edge. The application of the above solution facilitates a significant increase in the accuracy of determining the position of a blind person compared to the accuracy offered by commonly used ground satellite devices. The system uses thermal energy accumulated in the environment without the need to generate additional signals. The main parts of the system are a simple infrared matrix, data processing system and vibrating wristband. Messages and navigation warnings are sent to a blind person in the form of a vibration code. The article describes the method of determining the path of a specified width and distance from the wall of a building, curb, etc., along which a blind person should move. The article additionally describes the method of determining the orientation of a blind person depending on the selected object. Such a method facilitates verifying whether the visually impaired person is moving according to the indicated direction. The method can also be used to navigate mobile robots. Due to the use of natural energy for data registration and processing, the mobile navigation system can be operated for a long time without the need to recharge the battery.