Spatial random multiple access with multiple departure

We introduce a new model of spatial random multiple access systems with a non-standard departure policy: all arriving messages are distributed uniformly on a finite sphere in the space, and when a successful transmission of a single message occurs, the transmitted message leaves the system together with all its neighbours within a ball of a given radius centred at the message's location. We consider three classes of protocols: centralised protocols and decentralised protocols with either ternary or binary feedback; and analyse their stability. Further, we discuss some asymptotic properties of stable protocols

Research of MEMS accelerometers features in mobile phone

The purpose of this study is exploring the possibilities of MEMS accelerometer of mobile phone Nokia N900 to determine human gait or similar tasks. This study answers the question of whether you can use this sensor to solve these problems. Main emphasis is on accelerometer-based human gait identification. Previous studies proved that human gait contains very distinctive patterns that can be used for identification and verification purposes. There are different approaches for identification of a gait: accelerometers [1], sensors on the floor [2], motion analysis system, image registration. This means that person can be recognized by his walking style using MEMS accelerometers, which modern phones are equipped by

Energy-efficient communication system based on nonlinear scattering of standard OFDM signals

Development of miniaturized communication systems for exchanging data over short distances with little power consumption is an actual problem. This problem is solved by such standards as Bluetooth, ZigBee etc. Nowadays for extra size devices with power supply from external electromagnetic field are considered. In the paper we propose using nonlinear scattering effect for reusing energy radiated with standard wireless devices such as mobile phones, access points etc. For proposed solution link budget estimation is given. Performance of different types of receivers in communications system is investigated with both theoretical analysis and simulation

Analysis and Simulation of NAMA Algorithm for Decentralized Network

The object of research is modern decentralized communication system, which can contain quite a large number of users. Actual problem in this area is the study of algorithms of dynamic scheduling of users access to the communication channel. In this work algorithm NAMA is considered and the results of the analysis of its main characteristics are given

"Tap2smart": a New Lock-screen Option for Modern Smartphones

Nowadays, besides being used as phones, smart­ pbones involve a lot of such important additional functions as being organizer, valet, ID etc. That is why the users are to be sure, that their personal data kept In a smartphone Is reliably protected incase of device loss or theft. One of the basic security mechanisms is a lock screen and modem smartphone has a lot of difrereot lock screeo options (e.g. PIN, pattern etc.). In this paper we consider a new user hybrid scheme based on tapping the rhythmic sequence on a lock screen. For the scheme we propose a decision making algorithm based on statistical analysis of tapped sequence which provides a high steadiness and a continuous adaptation to a user