Search results for "SNS"
showing 10 items of 31 documents
An RF Wireless Power Transfer system to power battery-free devices for asset tracking
2019
Internet of Things (IoT) and Wireless Sensor Networks (WSN) infrastructures are becoming more and more available and diffused. One major outcome is the development of new services that help to make everyday life easier and better. One of those to which this paper reserves special attention is asset tracking which refers to the method of tracking physical assets. This service is very well based on IoT infrastructure and, due to the enormous number of objects to be traced, desperately needs the availability of inexpensive tags with sensing capabilities, that can be conveniently monitored from a long distance and require no maintenance. For this, engineers are called to face very challenging i…
A Battery-free Asset Monitoring System based on RF Wireless Power Transfer
2020
In the Internet of Things (IoT) era, asset monitoring represents an appealing implementation of Wireless Sensor Networks due to the enormous benefits associated with being able to monitor and record the exact position and transportation conditions of assets, personal objects, and the like. This kind of infrastructure enables the provision of increasingly advanced services, including the ability to measure the movement speed of a monitored asset using relatively inexpensive nodes with sensing capabilities and wireless transmission and reception. These nodes would ideally employ battery-free sensors that do not require any maintenance, but conventional power supply management systems cannot s…
Analysis of the Effect of Human Presence on a Wireless Sensor Network
2011
Wireless Sensor Networks (WSNs) are gaining an increasing industry wide adoption. However, there remain major challenges such as network dimensioning and node placement especially in Built Environment Networks (BENs). Decisions on the node placement, orientation, and the number of nodes to cover the area of interest are usually ad-hoc. Ray tracing tools are traditionally employed to predict RF signal propagation; however, such tools are primarily intended for outdoor environments. RF signal propagation varies greatly indoors due to building materials and infrastructure, obstacles, node placement, antenna orientation and human presence. Because of the complexity of signal prediction, these f…
Taisnspārņu (Orthoptera) indikatoru īpašību izpēte sausos, kaļķainos zālājos dabas parkā Abavas senleja
2016
Sausiem, kaļķainiem zālājiem ir augsta botāniskā vērtība, kas nodrošina arī daudzveidīgas un raksturīgas faunas pastāvēšanu. Taisnspārņi ir nozīmīga dabisko zālāju ekosistēmu sastāvdaļa. Pētījuma mērķis ir izpētīt iespējas izmantot taisnspārņus sausu,kaļķainu zālāju kvalitātes un apsaimniekošanas indikācijā. Dabas parkā „Abavas senleja” dažādas kvalitātes, dažādi apsaimniekotos kaļķainos zālājos un kultivētos zālājos tika ievākti taisnspārņu paraugi un raksturota veģetācija. Lielākā taisnspārņu daudzveidība konstatēta ekstensīvi ganītos, kaļķainos zālājos, bet zālāju apsaimniekošanas pārtraukšana negatīvi ietekmēja taisnspārņu daudzveidību un populāciju blīvumu. Izdalītas divas indikatorsug…
UAV-Assisted Data Collection in Wireless Sensor Networks: A Comprehensive Survey
2021
Wireless sensor networks (WSNs) are usually deployed to different areas of interest to sense phenomena, process sensed data, and take actions accordingly. The networks are integrated with many advanced technologies to be able to fulfill their tasks that is becoming more and more complicated. These networks tend to connect to multimedia networks and to process huge data over long distances. Due to the limited resources of static sensor nodes, WSNs need to cooperate with mobile robots such as unmanned ground vehicles (UGVs), or unmanned aerial vehicles (UAVs) in their developments. The mobile devices show their maneuverability, computational and energy-storage abilities to support WSNs in mul…
Speed detection of battery-free nodes based on RF Wireless Power Transfer
2020
In the Internet of Things (IoT) era, Wireless Sensor Networks (WSNs) are rapidly increasing in terms of relevance and pervasiveness thanks to their notable real-time monitoring performance across several fields, including industrial, domestic, military, biomedical, commercial, environmental, and other sectors. A highly attractive implementation of WSNs is asset tracking with accurate data regarding the location and transportation conditions of goods, equipment, and the like. One highly promising application of WSNs along these lines is the remote speed monitoring of goods, ideally with battery-free sensor nodes that do not require any maintenance. This, however, represents a major challenge…
Risinājumu skaita noteikšana polimino iepakošanas problēmai taisnstūros
2019
Tiks izpētītas dažādas polimino iepakošanas problēmas, to atrisināmība un sarežģītība. Tiks piedāvāti iepakošanas reģioni, kuri iepriekš nebija pietiekami detalizēti izpētīti. Tiem būs uzbūvēta hierarhija – no kura reģiona iepakošanas iespējamības seko citu reģionu iepakošanas iespējamība, ka arī doti piemēri. Tiks apskatīti esošie algoritmi risinājumu meklēšanai un pielāgoti piedāvātiem iepakošanas reģioniem, ka arī tiks aprakstīts salīdzinoši efektīvs algoritms risinājumu saskaitīšanai un algoritms risinājumu skaita formulas atrašanai. Tiks realizēti trīs algoritmi un izmēģināti uz vairākām polimino kopām, rezultāti tiks apkopoti tabulās un publicēti autora tīmekļa lapā.
Four essays on IT users' psychological states and behaviors
2016
This dissertation is intended to study information technology (IT) users’ psychological states and behaviors. It consists of four essays. The first essay examines how people react to social networking services (SNS). In this essay, we attempted to extend the existing model, which includes dedication- and constraint-based mechanisms, by additionally including the obligation-based mechanism underlying SNS-related behavior. The second essay is designed to investigate individuals’ smartphone use. In particular, we focused on the role of smartphone addiction in shaping individuals’ perceptions about their smartphone. The third essay is about online community behavior. Drawing on the model of eng…
Development of niobium-based superconducting junctions
2012
This thesis presents a review of publications which mainly focuses on the fabrication and performance of Nb-based normal metal-insulator-superconductor (NIS) tunnel junctions and superconductor-normal metal-superconductor (SNS) Josephson junctions at low temperatures. The Cu/AlOx-Al/Nb based NIS double tunnel junctions were successfully fabricated using conventional electron beam lithography combined with multi-angle thermal evaporation of metals in ultra high vacuum. The subgap characteristics of these junctions showed expected temperature dependence from 0.2 K to 5 K with a good thermometry sensitivity 0.2-0.3 mV/K. Signatures of small electronic cooling effects were observed near the Nb …