{"id":152,"date":"2010-07-29T14:00:50","date_gmt":"2010-07-29T12:00:50","guid":{"rendered":"https:\/\/samovar2022.int-evry.fr\/index.php\/2010\/07\/29\/soutenance-these-de-ashish-gupta\/"},"modified":"2020-09-04T18:47:17","modified_gmt":"2020-09-04T16:47:17","slug":"soutenance-these-de-ashish-gupta","status":"publish","type":"post","link":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/2010\/07\/29\/soutenance-these-de-ashish-gupta\/","title":{"rendered":"SOUTENANCE : th\u00e8se de Ashish Gupta"},"content":{"rendered":"

vendredi 10<\/strong> septembre 2010<\/p>\n

\u00ab\u00a0Empirical Analysis of Wirless Sensor Networks\u00a0\u00bb<\/strong><\/p>\n

Abstract<\/strong><\/p>\n

Wireless sensor networks are the collection of wireless nodes that are deployed to monitor certain phenomena of interest. Once the node takes measurements it transmits to a base station over a wireless channel. The base station collects data from all the nodes and do further analysis.
\nTo save energy, it is often useful to build clusters, and the head of each cluster communicates with the base station.<\/p>\n

Initially, we do the simulation analysis of the Zigbee networks where few nodes are more powerful than the other nodes. The results show that in the mobile heterogeneous sensor networks, due to phenomenon orphaning and high cost of route discovery and maintenance, the performance of the network degrades with respect to the homogeneous network.<\/p>\n

The core of this thesis is to empirically analyze the sensor network.
\nDue to its resource constraints, low power wireless sensor networks face several technical challenges. Many protocols work well on simulators but do not act as we expect in the actual deployments. For example, sensors physically placed at the top of the heap experience Free Space propagation model, while the sensors which are at the bottom of the heap have sharp fading channel characteristics.<\/p>\n

In this thesis, we show that impact of asymmetric links in the wireless sensor network topology and that link quality between sensors varies consistently. We propose two ways to improve the performance of Link Quality Indicator (LQI) based algorithms in the real asymmetric link sensor networks. In the first way, network has no choice but to have some sensors which can transmit over the larger distance and become cluster heads. The number of cluster heads can be given by Mat\u00e9rn Hard-Core process. In the second solution, we propose HybridLQI which improves the performance of LQI based algorithm without adding any overhead on the network.<\/p>\n

Later, we apply theoretical clustering approaches in sensor network to real world. We deploy Mat\u00e9rn Hard Core Process and Max-Min cluster Formation heuristic on real Tmote nodes in sparse as well as highly dense networks. Empirical results show clustering process based on Mat\u00e9rn Hard Core Process outperforms Max-Min Cluster formation in terms of the memory requirement, ease of implementation and number of messages needed for clustering.<\/p>\n

Finally, using Absorbing Markov chain and measurements we study the performance of load balancing techniques in real sensor networks.<\/p>\n

R\u00e9sum\u00e9<\/strong><\/p>\n

Les r\u00e9seaux de capteurs sans fil sont une collection de n\u0153uds non
\nconnect\u00e9s qui sont install\u00e9s pour la d\u00e9tection de certains ph\u00e9nom\u00e8nes
\nint\u00e9ressants. Apr\u00e8s avoir pris des mesures un capteur sans fil
\nretransmet ces mesures \u00e0 la station de base. La station de base collecte
\nles donn\u00e9es de tous les capteurs et les analyse. Pour \u00e9conomiser
\nl\u2019\u00e9nergie il est souvent utilise de grouper les capteurs en clusters,
\nchaque cluster ayant une t\u00eate de cluster qui communique avec la station
\nde base.<\/p>\n

Au d\u00e9but, on commence par analyser la simulation des r\u00e9seaux Zigbee o\u00f9
\nil y a quelques n\u0153uds qui transmettent avec diff\u00e9rentes puissances. Les
\nr\u00e9sultats montrent que dans les r\u00e9seaux de capteurs mobiles et
\nh\u00e9t\u00e9rog\u00e8nes et \u00e0 cause du ph\u00e9nom\u00e8ne d\u2019isolation des n\u0153uds et du co\u00fbt
\ntr\u00e8s \u00e9lev\u00e9 du routage et la maintenance, les performances sont moins
\nbonnes que celles des r\u00e9seaux homog\u00e8nes.<\/p>\n

Le but principal de cette th\u00e8se est de faire une analyse empirique des
\nr\u00e9seaux de capteurs. A cause de leurs ressources limit\u00e9es les r\u00e9seaux de
\ncapteurs doivent faire face \u00e0 plusieurs d\u00e9fis techniques. Beaucoup de
\nprotocoles fonctionnent tr\u00e8s bien dans les simulateurs mais pas aussi
\nbien en impl\u00e9mentation r\u00e9elle. Par exemple, les capteurs d\u00e9pos\u00e9s sur un
\nobjet \u00e9lev\u00e9 subissent moins d\u2019att\u00e9nuation que les autres capteurs plac\u00e9s
\nsur le sol.<\/p>\n

Dans cette th\u00e8se, on montre qu\u2019il y a un impact des liens asym\u00e9triques
\nsur la topologie des r\u00e9seaux de capteurs sans fil et que la qualit\u00e9 des
\nliens (LQI) varie en permanence. On propose deux m\u00e9thodes pour am\u00e9liorer
\nles performances des algorithmes bas\u00e9s sur la qualit\u00e9 des liens des
\nr\u00e9seaux de capteurs avec des liens asym\u00e9triques. Dans la premi\u00e8re
\nm\u00e9thode, le r\u00e9seau n\u2019a pas d\u2019autre choix que d\u2019avoir des n\u0153uds qui
\ntransmettent \u00e0 des grandes distances et deviennent des clusters Head. Le
\nnombre de clusters Head peut \u00eatre donn\u00e9 par Mat\u00e9rn Hard-core process.
\nDans la seconde m\u00e9thode, on propose HybridLQI qui am\u00e9liore les
\nalgorithmes bas\u00e9s sur LQI sans ajouter des ent\u00eates au r\u00e9seau.<\/p>\n

Ensuite, on applique les approches de clust\u00e9risassions th\u00e9oriques sur le
\nr\u00e9seau de capteurs r\u00e9el. On applique Mat\u00e9rn Hard Core process et Max-Min
\nheuristique de formation des clusters sur des n\u0153uds \u00abTmote \u00bb dans des
\nr\u00e9seaux denses et des r\u00e9seaux de faible densit\u00e9. Les r\u00e9sultats
\nempiriques ont montr\u00e9 la sup\u00e9riorit\u00e9 de Mat\u00e9rn sur Max-Min dans les
\nbesoins d\u2019espace m\u00e9moire, la simplicit\u00e9 de l\u2019impl\u00e9mentation et le nombre
\nde messages de signalisation.<\/p>\n

Enfin, en utilisant les cha\u00eenes de Markov absorbantes et des mesures, on
\n\u00e9tudie les performances des techniques de la distribution de charge dans
\ndes r\u00e9seaux de capteurs r\u00e9els.<\/p>\n

Jury<\/strong> :<\/p>\n

– Prof. Paul. J. KUEHN<\/strong>
\nUniversit\u00e9 de Stuttgart. Rapporteur
\n– Prof. Andr\u00e9-Luc BEYLOT<\/strong>
\nIRIT-ENSEEIHT. Rapporteur
\n– Dr. Frederica DAREMA<\/strong>
\nAFOSR, USA. Examinateur
\n– Prof. Guy PUJOLLE<\/strong>
\nParis 6. Examinateur
\n– Dr. Didier PERINO<\/strong>
\nHLP, Paris. Invit\u00e9
\n– Dr. Riadh DHAOU<\/strong>
\nRIT-ENSEEIHT. Examinateur
\n– Prof. Monique BECKER<\/strong>
\nTMSP. Directeur de th\u00e8se
\n– Prof. Michel MAROT<\/strong>
\nTMSP. Encadrant<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

vendredi 10 septembre 2010 \u00ab\u00a0Empirical Analysis of Wirless Sensor Networks\u00a0\u00bb Abstract Wireless sensor networks are the collection of wireless nodes that are deployed to monitor certain phenomena of interest. Once the node takes measurements it transmits to a base station over a wireless channel. The base station collects data from all the nodes and do […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"","ocean_second_sidebar":"","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"","ocean_custom_header_template":"","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"","ocean_menu_typo_font_family":"","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"","ocean_post_oembed":"","ocean_post_self_hosted_media":"","ocean_post_video_embed":"","ocean_link_format":"","ocean_link_format_target":"self","ocean_quote_format":"","ocean_quote_format_link":"post","ocean_gallery_link_images":"on","ocean_gallery_id":[],"footnotes":""},"categories":[7],"tags":[],"class_list":["post-152","post","type-post","status-publish","format-standard","hentry","category-uncategorized-fr","entry"],"_links":{"self":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/152","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/comments?post=152"}],"version-history":[{"count":1,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/152\/revisions"}],"predecessor-version":[{"id":2069,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/152\/revisions\/2069"}],"wp:attachment":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/media?parent=152"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/categories?post=152"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/tags?post=152"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}