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Wireless nodes are small devices which are distributed in the region of interest. These small devices measure selected environmental variables, communicate with each other and send data to a local storage. Wireless nodes can be distributed either in internal or external environment. Communication distance is one of factors that has to be known at the beginning of the distribution process. Communication distance depends on a lot of factors such as used protocol, technical parameters of the node, obstacles situated in the communication path and weather conditions. The communication distance between Jennic nodes with different antenna modules and a coordinator was tested in the small area. The nodes communicated on the basis of JeNet protocol. Four different scenarios represent the results of investigation of the communication distance at which the Jennic nodes are able reliable communicate. Knowledge of reliable communication distance is one of parameters used in the distribution process. [ABSTRACT FROM AUTHOR]

Wireless sensor networks are nowadays used both in environmental and socioeconomic fields. Environmental monitoring includes observing of basic meteorological variables, air pollutants, volcanic activity, landslides, etc. The major purpose of wireless nodes equipped with sensors is to collect data about selected environmental variables and send them to a gateway which is a gathering point of the whole wireless sensor network Temperature and air humidity values are measured at the predefined height, orientation and recording interval. These data show weather characteristics of the area of interest in days when the measurements were realized. The changes of temperature and air humidity values can be recorded in a small area in case that the measurement units are there distributed with high density. The knowledge of temperature and humidity characteristics of places situated in the area of interest can help to discover the most suitable places for different activities that are carried out in this area. This study is aimed at the research of air temperature and relative humidity characteristics of the Botanic Garden in the centre of Olomouc City, Czech Republic. Temperature and humidity values were measured with sensors which were connected to wireless nodes, Waspmote Plug&Sense, produced by Libelium. Data from four nodes with sensors were used for the investigation of temperature characteristics. Data from one sensor recorded relative humidity characteristics. Temperature and humidity values from different positions within the Botanic Garden were graphically compared and visualized. Graph and map visualization showed the differences in measured values of selected variables in the Botanic Garden. [ABSTRACT FROM AUTHOR]

Air pollution is a serious problem all around the world. The highest contribution to rising emissions in the air is caused by burning of fossil fuels and transportation. Road traffic is a big problem in cities and developing countries where the number of cars is increasing. The major pollutants which are related to transportation are NOx, COx and VOC. It is necessary to monitor the values of these pollutants because they have to be held below their highest allowed limits. Wireless sensor network seems to be a good technology for measuring values of air pollutants in cities. Every wireless sensor network consists of (wireless) nodes equipped with needed sensors, gateway and server. The biggest advantage of this technology is that data are collected in a real time so that the most endangered areas can be warned in time. Nodes can be distributed in the area of interest with high density so that detailed information about air pollutants is obtained. Data obtained by sensors, recorded in nodes are sent to a gateway and resent to a server for a long time storage. This study focuses on usage of wireless sensor networks for monitoring of air pollutants related to traffic. Criteria for the selection of nodes with integrated demands on needed sensors were determined and evaluated by their importance. The optimal parameters for application of this kind of wireless sensor network were specified. Weight values of the selected criteria were established on the basis of four methods. The computed values of weight for determined criteria were compared and visualized. The most appropriate method for this kind of task was chosen. Determination of criteria and their weight values is a basis for selection of the most suitable nodes, sensors for determined task. [ABSTRACT FROM AUTHOR]