International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This article presents a measurement system based on the RS-485 interface. The presented system is an alternative solution for distributed measurement systems, which cannot be built using IEEE-488 interface due to distance limitation between elements of the system. The RS-485 interface is a base for communication between measurement instruments and uses a Master-Slave protocol to exchange data between them. One dedicated master device, usually a PC, controls all slave devices connected to the interface. To control measurement devices SCPI language is used. This solution simplifies communication between measurement devices and allows utilizing the HP-VEE environment to control any SCPI devices connected to the RS-485 network.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Wireless data acquisition began with sensors connected to some form of radio. Emergence of the IEEE 802.11 specification made possible the evolution of a high-speed, multi-channel, wireless data acquisition system using COTS, Commercial Off-The-Shelf, technology. After developing a sub-miniature telemetry system in the S-band for the US Air Force, the system delivered to the Air Force evolved into a high-speed, wireless data acquisition system for the commercial market.

Ένα μεγάλο ποσοστό των σφαλμάτων στα δίκτυα διανομής μέσης τάσης οφείλεται σε πλήγματα από κεραυνούς. Οι κεραυνοί μπορεί να προκαλέσουν στις γραμμές είτε απλές υπερτάσεις ή και καταστροφή των μονώσεων και του εξοπλισμού. Σαν αποτέλεσμα, τα σφάλματα μπορεί να είναι στιγμιαία (τα οποία αποτελούν και πλειοψηφία) ή μόνιμα που είναι και τα πιο σοβαρά και συνοδεύονται από οικονομικές επιπτώσεις. Σκοπός αυτής της διπλωματικής εργασίας είναι η μελέτη της συμπεριφοράς των γραμμών σε καταπονήσεις από κεραυνούς. Αναλύονται οι βασικοί παράγοντες που σχετίζονται με τα σφάλματα από κεραυνούς όπως, η πυκνότητα των κεραυνών στο έδαφος (GFD), ο αριθμός των σφαλμάτων από άμεσα πλήγματα και από πλήγματα σε παραπλήσια αντικείμενα και η σχέση αυτών με το σύνολο των πραγματικών σφαλμάτων που έχουν καταγραφεί. Επίσης παρουσιάζονται κάποια διαγράμματα όπου συγκρίνεται το ποσοστό των σφαλμάτων από κεραυνούς με τα υπόλοιπα είδη σφαλμάτων και η συχνότητα των σφαλμάτων από κεραυνούς ανά εποχή του έτους. Στόχος της μελέτης είναι η εφαρμογή της μεθόδου, που θα χρησιμοποιήσουμε για τη θεωρητική εκτίμηση σφαλμάτων, σε ένα πραγματικό σύστημα και οι αποκλίσεις που παρουσιάζει από τα πραγματικά δεδομένα, η πρόβλεψη των σφαλμάτων από κεραυνούς στις γραμμές διανομής και ο εντοπισμός των «ευάλωτων» τμημάτων του δικτύου μέσης τάσης. Τα αποτελέσματα μπορούν να χρησιμοποιηθούν για τη βελτίωση της συμπεριφοράς των γραμμών σε πλήγματα από κεραυνούς και την ελάττωση των σφαλμάτων. Στο πρώτο κεφάλαιο, γίνεται μια γενική περιγραφή των συστημάτων ηλεκτρικής ενέργειας (ΣΗΕ). Συγκεκριμένα, παρουσιάζεται η δομή των ΣΗΕ, οι βασικές τους λειτουργίες και τα είδη των σφαλμάτων που επηρεάζουν την λειτουργία τους και διαταράζουν την ευστάθειά τους. Στο δεύτερο κεφάλαιο, αναλύεται το φαινόμενο του κεραυνού και οι βασικές έννοιες που τον διέπουν. Περιγράφεται ο τρόπος δημιουργίας των εκκενώσεων, τα είδη των κεραυνών και γίνεται μια αναφορά στη γενική αρχή λειτουργίας των αλεξικέραυνων. Στο τρίτο κεφάλαιο, παρουσιάζεται ο οδηγός του IEEE για την βελτίωση της συμπεριφοράς των γραμμών διανομής έναντι κεραυνών, πάνω στην οποία βασίστηκε και η συγκεκριμένη διπλωματική εργασία. Σκοπός του οδηγού αυτού είναι να προσδιορίσει τους παράγοντες που συνεισφέρουν στις βλάβες από κεραυνό στις εναέριες γραμμές διανομής και να παρουσιάσει εναλλακτικές λύσεις για την μείωση των βραχυκυκλωμάτων. Στο τέταρτο κεφάλαιο, γίνεται η μελέτη των γραμμών διανομής της περιοχής των Τρικάλων. Αρχικά περιγράφεται το κλίμα και η μορφολογία της περιοχής που θα μελετηθεί. Στη συνέχεια, δίνεται η μεθοδολογία της μελέτης των γραμμών όπως συγκεντρώθηκε από τον οδηγό του προηγούμενου κεφαλαίου και στη συνέχεια γίνεται εφαρμογή της μεθοδολογίας αυτής στις γραμμές διανομής που τροφοδοτούν με ενέργεια τους οικισμούς και την πόλη των Τρικάλων. Τέλος, παρουσιάζονται συγκεντρωτικά τα αποτελέσματα για το δίκτυο μέσης τάσης για να δοθεί μια συνολική εικόνα και δίνονται κάποια στατιστικά σε σχέση με τις βλάβες από τα οποία θα εξάγουμε σημαντικά συμπεράσματα. Στο πέμπτο κεφάλαιο, παρουσιάζονται τα συμπεράσματα που εξήχθησαν από τα αποτελέσματα της μελέτης. Σχολιάζονται τα αποτελέσματα της θεωρητικής εκτίμησης των σφαλμάτων και της σχέσης τους με τα πραγματικά δεδομένα. Επίσης, αναλύονται τα διαγράμματα της μελέτης που δείχνουν τον αριθμό των πραγματικών σφαλμάτων από κεραυνούς σε κάθε γραμμή, το πλήθος αυτών ανά εποχή του έτους και η σχέση των σφαλμάτων από κεραυνούς με τα υπόλοιπα καταγεγραμμένα σφάλματα του δικτύου. / A significant share of faults on overhead distribution lines is caused by lightning. Lightning strikes may cause overvoltage or total destruction of insulation and equipment. As a result, faults are considered temporary (the majority of them) or permanent which are the most severe and are followed by economic consequences. This diploma thesis studies the lightning performance of electric power overhead distribution lines. Some of the basic factors such as lightning intensity measured by ground flash density (GFD), the number of direct strokes, the number of induced voltages from nearby strokes and their relation with the actual faults on overhead lines, are thoroughly studied. Moreover, diagrams comparing the faults caused by lightning with the rest of the faults that occur on overhead distribution lines are presented and finally the density of lightning strikes on each season is analyzed. The purpose of this diploma thesis is the application of the guide (that will be used for the estimation of the number of faults by lightning) on a real distribution system, the divergence between the guide’s estimations and the actual faults that occurred on the lines, the provision of faults caused by lightning on overhead distribution lines and the detection of the “weak” parts on the distribution system. The results can be used for the improvement of the lightning performance of overhead distribution lines and the reduction of faults caused by lightning. The first chapter provides general information about the electrical power systems. The general structure, their basic functions and the faults that occasionally occur and disrupt their stability are presented. The second chapter analyzes the incidence of lightning and its basic characteristics. The production of lightning discharges, the types of lighting and the general function of the arresters is described. The third chapter presents the IEEE guide for the improvement of the lightning performance of electric power overhead distribution lines which is used on this diploma thesis. The purpose of the guide is to define the parameters that contribute to faults by lightning and to present alternatives for reducing lightning-caused flashovers on overhead distribution lines. The fourth chapter contains the application of the guide on the distribution lines in the area of Trikala-Greece. In the beginning, the climate and the morphology of the area is described. Also, the methodology of the calculations which was extracted from the IEEE guide is given in specific steps and it is applied on the distribution lines that provide with energy the villages and the city of Trikala-Greece. Additionally, the final results are organized and presented in order to provide an overview of the area’s distribution system and important statistics and diagrams are provided that lead to significant conclusions. The fifth chapter contains the conclusions that were extracted from the fourth chapter’s calculations. The results of the theoretical fault estimation and their relation with the actual faults that were detected on the distribution system are analyzed. Furthermore, the diagrams that present the number of the actual lightning-faults that were detected on each distribution line, the number of faults by lightning that occur on every season and the number of faults by lightning in comparison with the rest of the faults that were detected on the distribution system are also explained and analyzed.

In this thesis we have focused in the wireless environment and how to run voice application over it. Conducive environment that makes it possible for the voice services to run in wireless is necessary. As we know this well that wireless is a contemporary technology due to it low cost and its effectiveness, and one major advantage of it is the mobility that is one fell free to move anywhere but have the access to the resource. So this makes wireless networks of great value, we in this thesis have focused on wireless LAN’s. In second part of the thesis we have shed some light on the VoIP showing how it works in the wireless environment. Analysis phase is relatively more important phase then the previous section which shows issues or hindrances in carrying voice over wireless environment. This analysis shows that these issues still prevails and should be addresses and the corresponding results are also discussed and by looking at those results we have derived a summery out of it. Next chapter we firstly tried to explain why we have chosen specific protocols and then showing some graphical representation measurements that are to address the problem based on the work done. We tried to evaluate EDCF and DCF as these play important role in handling real time applications like voice. After that we proposed a scheme through which these effects can be minimized and to enhance the method is necessary to avoid the issues still in effect. / Thesis is Part for Master program in Electrical Engineering with Emphasis on Telecommunication(2007-2009).We have had a very nice time doing this thesis as there was alot of learning. Our examinator was allways there to help us, we are thankfull to Richard for his endless support.

This work is concerned with the design design full functional nodes and to evaluate an application in wireless sensor network. The resulting designed product could form a reliable support for transferring data between nodes and a computer. MaxStream XBee ZNet 2.5 modules are chosen as the radio platform and LabVIEW as the virtual instrument for user interface.

Un réseau de capteur sans fil est un ensemble de noeuds communicants, généralement miniatures et capables de fonctionner avec peu d'énergie. Certaines applications imposent à ces réseaux de capteurs sans fil d'être économes en énergie pour prolonger la durée de vie du réseau, d'autres nécessitent un comportement déterministe qui se traduit généralement par des délais de traversée du réseau bornés et/ou un taux de trames perdues inférieur à un seuil critique. Pour économiser significativement de l'énergie, une entité doit se mettre en mode sommeil. Durant cette période, elle sera inactive donc incapable de participer à l'ativité du réseau. L'usage de périodes de sommeil est un handicap pour l'aspect déterministe et pour le respect de contraintes temporelles. Le travail de cette thèse est centré sur les spécifications, le dévelopement et l'évaluation sous différentes formes d'une méthode d'accès au medium adaptée au déterminisme et aux exigences de qualité de service telles que l'absence de collisions et la garantie d'un délai borné de bout-en-bout, tout en conservant une faible consommation énergétique. La solution proposée repose sur la segmentation temporelle des activités, une synchronisation multi-sauts et une différentiation de services basée sur des stratégies de routage adaptées.

The IEEE 802.15.4 standard is an interesting technology for use in Wireless Body Sensor Networks (WBSN), where entire networks of sensors are carried by humans. In many environments the sensor nodes experience external interference for example, when the WBSN is operated in the 2.4 GHz ISM band and the human moves in a densely populated city, it will likely experience WiFi interference, with a quickly changing ``interference landscape''. In this thesis we propose Adaptive Resource Allocation schemes, to be carried out by the WBSN, which provided noticeable performance gains in such environments. We investigate a range of adaptation schemes and assess their performance both through simulations and experimentally.

近幾年無線寬頻網路崛起，寄望WiMAX可以取代最後一哩，雖然WiMAX有QoS的設計，但是對於Call Admission Control、Bandwidth Allocation、Scheduler並沒有實際定義，給予廠商彈性設計。本篇論文提出以機器學習的方式依據網路狀態動態配置頻寬，以符合實際頻寬需求。 由於BS在配置頻寬的時候並沒有SS佇列的訊息，使得BS無法配置適合的頻寬，達到較好的效能，尤其是有期限的rtPS封包最為明顯。在系統負載較高的環境下，容易導致封包遺失提升，吞吐量降低的情形發生。因此本研究提出了支持向量機的方式，收集大量Training Data，訓練成動態頻寬配置模組；以動態配置適合的頻寬給rtPS，使rtPS在負載高的環境下的封包遺失率降低，且延遲能夠維持一定水準。搭配適應性頻寬配置策略，在低負載的環境下可以保留少許頻寬給Non Real Time Traffic，在高負載環境下，先滿足Real Time Traffic為原則。模擬工具採用NS 2-2.29、長庚大學-資策會的WiMAX模組，以及台大林智仁老師開發的支持向量機函式庫libSVM。 / In recent years, the rise of wireless broadband access networks. Hope that WiMAX can solve the last mile problem. Although WiMAX has QoS design, but for call admission control, bandwidth allocation, scheduler are not defined in standard. In this paper, we proposed a machine learning approach dynamic bandwidth allocation based on network state. BS because of the bandwidth allocation at a time when there is no message of SS’s queue. Enables BS can not configure a more suitable bandwidth to achieve better performance. In particular, there is the deadline of rtPS packets. At the higher loading on the system environment, easily lead to packet loss raise, lower throughput situations happen. In this study, a support vector machine approach to collect a large number of training data. Training modules into a dynamic bandwidth allocation. We can dynamically allocate bandwidth to fit rtPS. Adaptive bandwidth allocation strategy, at the low loading environment can keep some bandwidth for non real time traffic. At a high loading environment must first meet the real time traffic. We use Network Simulator 2-2.29, CGU-III WiMAX module, libSVM library.

IEEE 802.11n Wireless Local Area Networks (WLANs) employ Multiple-Input-Multiple-Output (MIMO), which significantly boosts the raw data rate at the Physical layer (PHY). But the potential of enhancing Medium Access Control (MAC) layer efficiencies by MIMO is still in its early stage and is the aim of the research in this thesis. Many existing works in this field mainly employ distributed MIMO spatial multiplexing/Multi-User Detection (MUD) technique and stream sharing to enable multiple simultaneous transmissions. Most works require synchronization among multiple transmissions, split the channel, and aim for single-hop networks. In this thesis, a novel Hybrid Carrier Sense (HCS) framework is proposed, mainly at the MAC layer to exploit the power of MIMO. HCS senses the channel availability jointly by the virtual carrier sense and physical carrier sense. HCS does not require synchronization among nodes; each node independently and locally determines when to start its transmission. HCS not only shares the channel, but also exploits the bi-directional handshakes of the wireless transmissions and increases the number of simultaneous stream transmissions. For a network with M antennas in each node, HCS can accommodate 2x(M-1) streams instead of M streams achieved by all other existing works. Moreover, HCS is aimed for multi-hop wireless ad hoc networks, in which the hidden terminal, exposed terminal, and deafness problems greatly degrade network performance. The HCS framework incorporates solutions to these problems. HCS is implemented in an NS2 network simulator and the performance evaluation shows that HCS significantly outperforms MIMO-enabled IEEE 802.11 (in which MIMO is only used for enhancing the raw data rate in the physical layer), resulting in higher aggregate throughput, packet delivery ratio and fairness in multi-hop wireless ad hoc networks. The HCS framework will be in wide use in the future generation of wireless networks and opens up more research possibilities. Some ideas in the HCS framework can be applied not only for MIMO, but also for many other techniques surveyed in this thesis; or we may combine them with HCS to further boost the network performance. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2013-10-15 21:46:15.983

Within the nuclear industry, there have been numerous instances of radio transmissions interfering with sensitive plant equipment. Instances documented vary from minor instrument fluctuations to major plant transients including reactor trips. With the nuclear power industry moving toward digital technologies for control and reactor protection systems, concern exists regarding their potential susceptibility to contemporary wireless telecommunications technologies. This study evaluates the susceptibility of Comanche Peak's planned turbine controls upgrade to IEEE 802.11 compliant wireless radio emissions. The study includes a review of previous research, industry emissions standards, and technical overview of the various IEEE 802.11 protocols and details the testing methodology utilized to evaluate the digital control system. The results of this study concluded that the subject digital control system was unaffected by IEEE 802.11 compliant emissions even when the transmitter was in direct contact with sensitive components.