Taxonomy Icon Data: Japanese Ratsnake [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Japanese Ratsnake Elaphe climacophora Chordata/Vertebrata/Reptilia/etc Elaphe_climacophora_L.png Elaphe_clim...acophora_NL.png Elaphe_climacophora_S.png Elaphe_climacophora_NS.png http://bioscie...ncedbc.jp/taxonomy_icon/icon.cgi?i=Elaphe+climacophora&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Elaphe+clima...cophora&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Elaphe+clima...cophora&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Elaphe+climacophora&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=3 ...

Taxonomy Icon Data: Oryzias javanicus [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Oryzias javanicus Oryzias javanicus Chordata/Vertebrata/Pisciformes Oryzias_javanicus_L.png Oryzias_java...nicus_NL.png Oryzias_javanicus_S.png Oryzias_javanicus_NS.png http://biosciencedbc.jp/t...axonomy_icon/icon.cgi?i=Oryzias+javanicus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Oryzias+javan...icus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Oryzias+javanicus&t=S ...http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Oryzias+javanicus&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=77 ...

Taxonomy Icon Data: Schistosoma japonicum [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Schistosoma japonicum Schistosoma japonicum Platyhelminthes Schistosoma_japonicum_L.png Schistoso...ma_japonicum_NL.png Schistosoma_japonicum_S.png Schistosoma_japonicum_NS.png http://bioscience...dbc.jp/taxonomy_icon/icon.cgi?i=Schistosoma+japonicum&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schistoso...ma+japonicum&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schistoso...ma+japonicum&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schistosoma+japonicum&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=132 ...

Taxonomy Icon Data: honey bee [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available honey bee Apis mellifera Arthropoda Apis_mellifera_L.png Apis_mellifera_NL.png Apis_mellife...ra_S.png Apis_mellifera_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Apis+mellifera&t=L h...ttp://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Apis+mellifera&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Apis+mellife...ra&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Apis+mellifera&t=NS ...

Taxonomy Icon Data: thale cress [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available thale cress Arabidopsis thaliana Arabidopsis_thaliana_L.png Arabidopsis_thaliana_NL.png Arabidopsis_thal...iana_S.png Arabidopsis_thaliana_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Arabidopsis+thal...iana&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Arabidopsis+thaliana&t=NL http://...biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Arabidopsis+thaliana&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Arabidopsis+thaliana&t=NS ...

Taxonomy Icon Data: Lotus corniculatus [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Lotus corniculatus Lotus corniculatus Lotus_corniculatus_L.png Lotus_corniculatus_NL.png Lotus_corn...iculatus_S.png Lotus_corniculatus_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+corn...iculatus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+corniculatus&t=NL http://bioscie...ncedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+corniculatus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+corniculatus&t=NS ...

Taxonomy Icon Data: fission yeast [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available fission yeast Schizosaccharomyces pombe Schizosaccharomyces_pombe_L.png Schizosaccharomyce...s_pombe_NL.png Schizosaccharomyces_pombe_S.png Schizosaccharomyces_pombe_NS.png http://biosciencedbc....jp/taxonomy_icon/icon.cgi?i=Schizosaccharomyces+pombe&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schizosaccharomyce...s+pombe&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schizosaccharomyce...s+pombe&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schizosaccharomyces+pombe&t=NS

Taxonomy Icon Data: barrel medic [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available barrel medic Medicago truncatula Medicago_truncatula_L.png Medicago_truncatula_NL.png Medi...cago_truncatula_S.png Medicago_truncatula_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Medi...cago+truncatula&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Medicago+truncatula&t=NL http://biosci...encedbc.jp/taxonomy_icon/icon.cgi?i=Medicago+truncatula&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Medicago+truncatula&t=NS ...

Taxonomy Icon Data: fruit fly [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available fruit fly Drosophila melanogaster Arthropoda Drosophila_melanogaster_L.png Drosophila_mela...nogaster_NL.png Drosophila_melanogaster_S.png Drosophila_melanogaster_NS.png http://biosciencedbc.jp/...taxonomy_icon/icon.cgi?i=Drosophila+melanogaster&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Drosophila+mela...nogaster&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Drosophila+mela...nogaster&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Drosophila+melanogaster&t=NS ...

Taxonomy Icon Data: Lotus japonicus [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Lotus japonicus Lotus japonicus Lotus_japonicus_L.png Lotus_japonicus_NL.png Lotus_japonicus_S.png Lotus_jap...onicus_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+japonicus&t=L ...http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+japonicus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+jap...onicus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Lotus+japonicus&t=NS ...

Taxonomy Icon Data: Asiatic tapir [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Asiatic tapir Tapirus indicus Chordata/Vertebrata/Mammalia/Theria/Eutheria/etc. Tapirus_indicus_L.png Tapi...rus_indicus_NL.png Tapirus_indicus_S.png Tapirus_indicus_NS.png http://biosciencedbc....jp/taxonomy_icon/icon.cgi?i=Tapirus+indicus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Tapirus+ind...icus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Tapirus+indicus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Tapirus+indicus&t=NS ...

Taxonomy Icon Data: fathead minnow [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available fathead minnow Pimephales promelas Chordata/Vertebrata/Pisciformes Pimephales_promela...s_L.png Pimephales_promelas_NL.png Pimephales_promelas_S.png Pimephales_promelas_NS.png http://bioscienced...bc.jp/taxonomy_icon/icon.cgi?i=Pimephales+promelas&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Pimephales+promela...s&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Pimephales+promela...s&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Pimephales+promelas&t=NS ...

Taxonomy Icon Data: white shark [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available white shark Carcharodon carcharias Chordata/Vertebrata/Pisciformes Carcharodon_carcharias_L.png Carcharo...don_carcharias_NL.png Carcharodon_carcharias_S.png Carcharodon_carcharias_NS.png http:/.../biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharodon+carcharias&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharo...don+carcharias&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharo...don+carcharias&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharodon+carcharias&t=NS ...

Taxonomy Icon Data: sperm whale [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available sperm whale Physeter macrocephalus Chordata/Vertebrata/Mammalia/Theria/Eutheria/Cetacea Physeter_macrocephal...us_L.png Physeter_macrocephalus_NL.png Physeter_macrocephalus_S.png Physeter_macrocephal...us_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Physeter+macrocephalus&t=L http://bioscience...dbc.jp/taxonomy_icon/icon.cgi?i=Physeter+macrocephalus&t=NL http://biosciencedbc....jp/taxonomy_icon/icon.cgi?i=Physeter+macrocephalus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Physeter+macrocephalus&t=NS ...

Taxonomy Icon Data: Asiatic elephant [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Asiatic elephant Elephas maximus Chordata/Vertebrata/Mammalia/Theria/Eutheria/etc. Elephas_maxim...us_L.png Elephas_maximus_NL.png Elephas_maximus_S.png Elephas_maximus_NS.png http://bioscienced...bc.jp/taxonomy_icon/icon.cgi?i=Elephas+maximus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Elephas+maxim...us&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Elephas+maximus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Elephas+maximus&t=NS ...

Taxonomy Icon Data: Japanese serow [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Japanese serow Capricornis crispus Chordata/Vertebrata/Mammalia/Theria/Eutheria/Artiodactyla Capricorn...is_crispus_L.png Capricornis_crispus_NL.png Capricornis_crispus_S.png Capricornis_crispus..._NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Capricornis+crispus&t=L http://biosciencedbc.jp/tax...onomy_icon/icon.cgi?i=Capricornis+crispus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Capricorn...is+crispus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Capricornis+crispus&t=NS ...

Taxonomy Icon Data: Arabian camel [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Arabian camel Camelus dromedarius Chordata/Vertebrata/Mammalia/Theria/Eutheria/Artiodactyla Camel...us_dromedarius_L.png Camelus_dromedarius_NL.png Camelus_dromedarius_S.png Camelus_dromedarius_...NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Camelus+dromedarius&t=L http://biosciencedbc.jp/taxo...nomy_icon/icon.cgi?i=Camelus+dromedarius&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Camel...us+dromedarius&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Camelus+dromedarius&t=NS ...

Taxonomy Icon Data: giant panda [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available giant panda Ailuropoda melanoleuca Chordata/Vertebrata/Mammalia/Theria/Eutheria/Carnivora Ailuropoda_mela...noleuca_L.png Ailuropoda_melanoleuca_NL.png Ailuropoda_melanoleuca_S.png Ailuropoda_mela...noleuca_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Ailuropoda+melanoleuca&t=L http://bioscien...cedbc.jp/taxonomy_icon/icon.cgi?i=Ailuropoda+melanoleuca&t=NL http://biosciencedb...c.jp/taxonomy_icon/icon.cgi?i=Ailuropoda+melanoleuca&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Ailuropoda+melanoleuca&t=NS ...

Taxonomy Icon Data: Guinea baboon [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Guinea baboon Papio papio Chordata/Vertebrata/Mammalia/Theria/Eutheria/Primate Papio_papio_L.png Papio_papi...o_NL.png Papio_papio_S.png Papio_papio_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Papio+papi...o&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Papio+papio&t=NL http://bioscien...cedbc.jp/taxonomy_icon/icon.cgi?i=Papio+papio&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Papio+papio&t=NS ...

Taxonomy Icon Data: Anopheles stephensi [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Anopheles stephensi Anopheles stephensi Arthropoda Anopheles_stephensi_L.png Anopheles_stephen...si_NL.png Anopheles_stephensi_S.png Anopheles_stephensi_NS.png http://biosciencedbc.jp/taxonomy_i...con/icon.cgi?i=Anopheles+stephensi&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Anopheles+stephensi&...t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Anopheles+stephensi&t=S htt...p://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Anopheles+stephensi&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=149 ...

Taxonomy Icon Data: moss [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available moss Physcomitrella patens subsp. patens. Physcomitrella_patens_subsp_patens_L.png Physcomitrella_patens..._subsp_patens_NL.png Physcomitrella_patens_subsp_patens_S.png Physcomitrella_patens_subsp_patens..._NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Physcomitrella+patens+subsp%2e+patens%2e&t...=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Physcomitrella+patens+subsp%2e+patens...%2e&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Physcomitrella+patens+subsp%2e+patens%2e&t

Invited Article: Channel performance for indoor and outdoor terahertz wireless links

Science.gov (United States)

Ma, Jianjun; Shrestha, Rabi; Moeller, Lothar; Mittleman, Daniel M.

2018-05-01

One of the most exciting future applications of terahertz technology is in the area of wireless communications. As 5G systems incorporating a standard for millimeter-wave wireless links approach commercial roll-out, it is becoming clear that even this new infrastructure will not be sufficient to keep pace with the rapidly increasing global demand for bandwidth. One favorable solution that is attracting increasing attention for subsequent generations of wireless technology is to use higher frequencies, above 100 GHz. The implementation of such links will require significant advances in hardware, algorithms, and architecture. Although numerous research groups are exploring aspects of this challenging problem, many basic questions remain unaddressed. Here, we present an experimental effort to characterize THz wireless links in both indoor and outdoor environments. We report measurements at 100, 200, 300, and 400 GHz, using a link with a data rate of 1 Gbit/s. We demonstrate both line-of-sight and non-line-of-sight (specular reflection) links off of interior building walls. This work represents a first step to establish the feasibility of using THz carrier waves for data transmission in diverse situations and environments.

Taxonomy Icon Data: Old world swallowtail [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Old world swallowtail Papilio machaon Arthropoda Papilio_machaon_L.png Papilio_machaon_NL.png Papilio_machao...n_S.png Papilio_machaon_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Papilio+machao...n&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Papilio+machaon&t=NL http://biosciencedbc....jp/taxonomy_icon/icon.cgi?i=Papilio+machaon&t=S http://biosciencedbc.jp/taxonomy_...icon/icon.cgi?i=Papilio+machaon&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=47 ...

Taxonomy Icon Data: Japanese Bush Warbler [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Japanese Bush Warbler Cettia diphone Chordata/Vertebrata/Aves Cettia_diphone_L.png Cettia_diphone..._NL.png Cettia_diphone_S.png Cettia_diphone_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Cettia+diphone...&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Cettia+diphone&t=NL http://bioscie...ncedbc.jp/taxonomy_icon/icon.cgi?i=Cettia+diphone&t=S http://biosciencedbc.jp/tax...onomy_icon/icon.cgi?i=Cettia+diphone&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=26 ...

Taxonomy Icon Data: Japanese tree frog [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Japanese tree frog Hyla japonica Chordata/Vertebrata/Amphibia Hyla_japonica_L.png Hyla_jap...onica_NL.png Hyla_japonica_S.png Hyla_japonica_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Hyla+jap...onica&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Hyla+japonica&t=NL http://biosciencedbc....jp/taxonomy_icon/icon.cgi?i=Hyla+japonica&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Hyla+jap

Taxonomy Icon Data: aye-aye [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available aye-aye Daubentonia madagascariensis Chordata/Vertebrata/Mammalia/Theria/Eutheria/Primate Daubentonia_madaga...scariensis_L.png Daubentonia_madagascariensis_NL.png Daubentonia_madagascariensis_S.png Daubentonia_madagasc...ariensis_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Daubentonia+madagascar...iensis&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Daubentonia+madagascar...iensis&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Daubentonia+madagascariensis&t=S http://bi

Taxonomy Icon Data: Pacific electric ray [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Pacific electric ray Torpedo californica Chordata/Vertebrata/Pisciformes Torpedo_californica_L.png Torpedo..._californica_NL.png Torpedo_californica_S.png Torpedo_californica_NS.png http://biosc...iencedbc.jp/taxonomy_icon/icon.cgi?i=Torpedo+californica&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Torpedo...+californica&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Torpedo...+californica&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Torpedo+californica&t=NS ...

Taxonomy Icon Data: Japanese giant salamander [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Japanese giant salamander Andrias japonicus Chordata/Vertebrata/Amphibia Andrias_japonicus_L.png Andrias_jap...onicus_NL.png Andrias_japonicus_S.png Andrias_japonicus_NS.png http://biosciencedbc....jp/taxonomy_icon/icon.cgi?i=Andrias+japonicus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Andrias+jap...onicus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Andrias+japonicus...&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Andrias+japonicus&t=NS ...

Taxonomy Icon Data: African savanna elephant [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available African savanna elephant Loxodonta africana Chordata/Vertebrata/Mammalia/Theria/Eutheria/etc. Loxodonta_afri...cana_L.png Loxodonta_africana_NL.png Loxodonta_africana_S.png Loxodonta_africana_NS....png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Loxodonta+africana&t=L http://biosciencedbc.jp/taxonom...y_icon/icon.cgi?i=Loxodonta+africana&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Loxodonta+afric...ana&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Loxodonta+africana&t=NS ...

Taxonomy Icon Data: Javan tree shrew [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Javan tree shrew Tupaia javanica Chordata/Vertebrata/Mammalia/Theria/Eutheria/etc. Tupaia_java...nica_L.png Tupaia_javanica_NL.png Tupaia_javanica_S.png Tupaia_javanica_NS.png http://bioscienced...bc.jp/taxonomy_icon/icon.cgi?i=Tupaia+javanica&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Tupaia+java...nica&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Tupaia+javanica&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Tupaia+javanica&t=NS ...

Taxonomy Icon Data: wild Bactrian camel [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available wild Bactrian camel Camelus ferus Chordata/Vertebrata/Mammalia/Theria/Eutheria/Artiodactyla Camel...us_ferus_L.png Camelus_ferus_NL.png Camelus_ferus_S.png Camelus_ferus_NS.png http://bioscience...dbc.jp/taxonomy_icon/icon.cgi?i=Camelus+ferus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Camelus+f...erus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Camelus+ferus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Camelus+ferus&t=NS ...

Taxonomy Icon Data: Diplazium tomitaroanum Masam [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Diplazium tomitaroanum Masam Diplazium tomitaroanum Masam Diplazium_tomitaroanum_Masam_L.png Diplazium_tomit...aroanum_Masam_NL.png Diplazium_tomitaroanum_Masam_S.png Diplazium_tomitaroanum_Masa...m_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Diplazium+tomitaroanum+Masam&t=L http://bioscience...dbc.jp/taxonomy_icon/icon.cgi?i=Diplazium+tomitaroanum+Masam&t=NL http://bioscien...cedbc.jp/taxonomy_icon/icon.cgi?i=Diplazium+tomitaroanum+Masam&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Diplazium+tomitaroanum+Masam&t=NS ...

High-Capacity Hybrid Optical Fiber-Wireless Communications Links in Access Networks

DEFF Research Database (Denmark)

Pang, Xiaodan

of broadband services access. To realize the seamless convergence between the two network segments, the lower capacity of wireless systems need to be increased to match the continuously increasing bandwidth of fiber-optic systems. The research works included in this thesis are devoted to experimental...... investigations of photonic-wireless links with record high capacities to fulfill the requirements of next generation hybrid optical fiber-wireless access networks. The main contributions of this thesis have expanded the state-of-the-art in two main areas: high speed millimeter-wave (mm-wave) communication links......Integration between fiber-optic and wireless communications systems in the "last mile" access networks is currently considered as a promising solution for both service providers and users, in terms of minimizing deployment cost, shortening upgrading period and increasing mobility and flexibility...

Performance prediction of a synchronization link for distributed aerospace wireless systems.

Science.gov (United States)

Wang, Wen-Qin; Shao, Huaizong

2013-01-01

For reasons of stealth and other operational advantages, distributed aerospace wireless systems have received much attention in recent years. In a distributed aerospace wireless system, since the transmitter and receiver placed on separated platforms which use independent master oscillators, there is no cancellation of low-frequency phase noise as in the monostatic cases. Thus, high accurate time and frequency synchronization techniques are required for distributed wireless systems. The use of a dedicated synchronization link to quantify and compensate oscillator frequency instability is investigated in this paper. With the mathematical statistical models of phase noise, closed-form analytic expressions for the synchronization link performance are derived. The possible error contributions including oscillator, phase-locked loop, and receiver noise are quantified. The link synchronization performance is predicted by utilizing the knowledge of the statistical models, system error contributions, and sampling considerations. Simulation results show that effective synchronization error compensation can be achieved by using this dedicated synchronization link.

Consistent sensor, relay, and link selection in wireless sensor networks

NARCIS (Netherlands)

Arroyo Valles, M.D.R.; Simonetto, A.; Leus, G.J.T.

2017-01-01

In wireless sensor networks, where energy is scarce, it is inefficient to have all nodes active because they consume a non-negligible amount of battery. In this paper we consider the problem of jointly selecting sensors, relays and links in a wireless sensor network where the active sensors need

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Lifescience Database Archive (English)

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Lifescience Database Archive (English)

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Invisible Bridges: Wireless Technology Links Minds over Space and Time

Science.gov (United States)

Lambert, Lori

2004-01-01

Eight years after Chief Sitting Bull, prophetic chief of the Great Sioux Nation, was assassinated in 1890, Guglielmo Marconi transmitted the first wireless telegraph signals across the Atlantic to England. Although these two events seem unrelated, the names of these two men of vision are linked together today by Marconi's wireless invention. Data,…

Robust optical wireless links over turbulent media using diversity solutions

Science.gov (United States)

Moradi, Hassan

Free-space optic (FSO) technology, i.e., optical wireless communication (OWC), is widely recognized as superior to radio frequency (RF) in many aspects. Visible and invisible optical wireless links solve first/last mile connectivity problems and provide secure, jam-free communication. FSO is license-free and delivers high-speed data rates in the order of Gigabits. Its advantages have fostered significant research efforts aimed at utilizing optical wireless communication, e.g. visible light communication (VLC), for high-speed, secure, indoor communication under the IEEE 802.15.7 standard. However, conventional optical wireless links demand precise optical alignment and suffer from atmospheric turbulence. When compared with RF, they suffer a low degree of reliability and lack robustness. Pointing errors cause optical transceiver misalignment, adversely affecting system reliability. Furthermore, atmospheric turbulence causes irradiance fluctuations and beam broadening of transmitted light. Innovative solutions to overcome limitations on the exploitation of high-speed optical wireless links are greatly needed. Spatial diversity is known to improve RF wireless communication systems. Similar diversity approaches can be adapted for FSO systems to improve its reliability and robustness; however, careful diversity design is needed since FSO apertures typically remain unbalanced as a result of FSO system sensitivity to misalignment. Conventional diversity combining schemes require persistent aperture monitoring and repetitive switching, thus increasing FSO implementation complexities. Furthermore, current RF diversity combining schemes may not be optimized to address the issue of unbalanced FSO receiving apertures. This dissertation investigates two efficient diversity combining schemes for multi-receiving FSO systems: switched diversity combining and generalized selection combining. Both can be exploited to reduce complexity and improve combining efficiency. Unlike maximum

IO-Link Wireless enhanced factory automation communication for Industry 4.0 applications

Directory of Open Access Journals (Sweden)

R. Heynicke

2018-03-01

Full Text Available In the context of the Industry 4.0 initiative, Cyber-Physical Production Systems (CPPS or Cyber Manufacturing Systems (CMS can be characterized as advanced networked mechatronic production systems gaining their added value by interaction with the ambient Industrial Internet of Things (IIoT. In this context appropriate communication technologies and standards play a vital role to realize the manifold potential improvements in the production process. One of these standards is IO-Link. In 2016 more than 5 million IO-Link nodes have been produced and delivered, still gaining increasing acceptance for the communication between sensors, actuators and the control level. The steadily increasing demand for more flexibility in automation solutions can be fulfilled using wireless technologies. With the wireless extension for the IO-Link standard, which will be presented in this article, maximum cycle times of 5 ms can be achieved with a probability that this limit will be exceeded to be at maximum one part per billion. Also roaming capabilities, wireless coexistence mechanisms and the possibility to include battery-powered or energy-harvesting sensors with very limited energy resources in the realtime network were defined. For system planning, setup, operation and maintenance, the standard engineering tools of IO-Link can be employed so that the backward compatibility with wired IO-Link solutions can be guaranteed. Interoperability between manufacturers is a key requirement for any communication standard, thus a procedure for IO-Link Wireless testing is also suggested.

Deflating link buffers in a wireless mesh network

KAUST Repository

Jamshaid, Kamran; Shihada, Basem; Showail, Ahmad; Levis, Philip

2014-01-01

We analyze the problem of buffer sizing for backlogged TCP flows in 802.11-based wireless mesh networks. Our objective is to maintain high network utilization while providing low queueing delays. Unlike wired networks where a single link buffer feeds a bottleneck link, the radio spectral resource in a mesh network is shared among a set of contending mesh routers. We account for this by formulating the buffer size problem as sizing a collective buffer distributed over a set of interfering nodes. In this paper we propose mechanisms for sizing and distributing this collective buffer among the mesh nodes constituting the network bottleneck. Our mechanism factors in the network topology and wireless link rates, improving on pre-set buffer allocations that cannot optimally work across the range of configurations achievable with 802.11 radios. We evaluate our mechanisms using simulations as well as experiments on a testbed. Our results show that we can reduce the RTT of a flow by 6× or more, at the cost of less than 10% drop in end-to-end flow throughput.

Deflating link buffers in a wireless mesh network

KAUST Repository

Jamshaid, Kamran

2014-05-01

We analyze the problem of buffer sizing for backlogged TCP flows in 802.11-based wireless mesh networks. Our objective is to maintain high network utilization while providing low queueing delays. Unlike wired networks where a single link buffer feeds a bottleneck link, the radio spectral resource in a mesh network is shared among a set of contending mesh routers. We account for this by formulating the buffer size problem as sizing a collective buffer distributed over a set of interfering nodes. In this paper we propose mechanisms for sizing and distributing this collective buffer among the mesh nodes constituting the network bottleneck. Our mechanism factors in the network topology and wireless link rates, improving on pre-set buffer allocations that cannot optimally work across the range of configurations achievable with 802.11 radios. We evaluate our mechanisms using simulations as well as experiments on a testbed. Our results show that we can reduce the RTT of a flow by 6× or more, at the cost of less than 10% drop in end-to-end flow throughput.

Link and route availability for Inter-working multi-hop wireless networks

CSIR Research Space (South Africa)

Salami, O

2009-09-01

Full Text Available pairs in inter-working multi-hop wireless networks can be evaluated based on the availability and reliability of radio links that form the communication path linking the nodes. This paper presents an analytical study of the link and route availability...

Microwave Photonics Techniques Supporting Flexible Wireless Communications Links

DEFF Research Database (Denmark)

Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José

Wireless data communication links supporting the next generation 5G and beyond mobile networking face a set of engineering challenges related to the mandatory operation at mmw and higher frequency bands, provide capacities above 10 Gb/s, satisfy latency, robustness, flexibility and low complexity...

An Inductive Link-Based Wireless Power Transfer System for Biomedical Applications

Directory of Open Access Journals (Sweden)

M. A. Adeeb

2012-01-01

Full Text Available A wireless power transfer system using an inductive link has been demonstrated for implantable sensor applications. The system is composed of two primary blocks: an inductive power transfer unit and a backward data communication unit. The inductive link performs two functions: coupling the required power from a wireless power supply system enabling battery-less, long-term implant operation and providing a backward data transmission path. The backward data communication unit transmits the data to an outside reader using FSK modulation scheme via the inductive link. To demonstrate the operation of the inductive link, a board-level design has been implemented with high link efficiency. Test results from a fabricated sensor system, composed of a hybrid implementation of custom-integrated circuits and board-level discrete components, are presented demonstrating power transmission of 125 mW with a 12.5% power link transmission efficiency. Simultaneous backward data communication involving a digital pulse rate of up to 10 kbps was also observed.

Millimeter Wave Hybrid Photonic Wireless Links for High-Speed Wireless Access and Mobile Fronthaul

DEFF Research Database (Denmark)

Rommel, Simon

As the introduction of the fifth generation of mobile services (5G) is set to revolutionize the way people, devices and machines connect, the changes to the underlying networks and technologies are no less drastic. The massive increase in user and data capacity, as well as the decrease in latency...... networks. In summary, the work presented in this thesis has regarded a multitude of aspects of millimeter wave hybrid photonic wireless links, expanding upon the state of the art and showing their feasibility for use in fifth generation mobile and high speed wireless access networks – hopefully bringing...

Impact of Various Parameters on the Performance of Inter-aircraft Optical Wireless Communication Link

Science.gov (United States)

Singh, Mehtab

2017-12-01

Optical wireless communication (OWC) systems also known as Free space optics (FSO) are capable of providing high channel bandwidth, high data transmission rates, low power consumption, and high security. OWC links are being considered in different applications such as inter-satellite links, terrestrial links, and inter-aircraft communication links. This paper investigates the impact of different system parameters such as transmission power level, operating wavelength, transmitter pointing error angle, bit transmission rate, atmospheric attenuation, antenna aperture diameter, geometric losses, the responsivity of the photodetector, and link range on the performance of inter-aircraft optical wireless communication link.

Optical wireless links with enhanced linearity and selectivity [Invited

Science.gov (United States)

Green, Roger J.; Sweet, C.; Idrus, S.

2005-10-01

Optical wireless is an attractive medium as an alternative to optical fiber communications, and also to RF, because of its high bandwidth and relative ease of use, especially when it comes to deployment in new physical situations. We describe an optical wireless link approach that offers a performance that gives analog transmission with significantly reduced distortion levels and enhanced reception sensitivity by combining a novel hybrid detector-amplifier technique. Reduction of distortion by 40 dB and improvement in sensitivity of 20-30 dB is possible, using the techniques described.

28 GHz Wireless Backhaul Transceiver Characterization and Radio Link Budget

Directory of Open Access Journals (Sweden)

Marko E. Leinonen

2018-02-01

Full Text Available Millimeter wave communication is one of the main disruptive technologies in upcoming 5G mobile networks. One of the first candidate applications, which will be commercially ready by 2020, is wireless backhaul links or wireless last mile communication. This paper provides an analysis of this use‐case from radio engineering and implementation perspectives. Furthermore, preliminary experimental results are shown for a proof‐of‐concept wireless backhaul solution developed within the EU‐KR 5GCHAMPION project, which will be showcased during the 2018 Winter Olympic Games in Korea. In this paper, we verify system level calculations and a theoretical link budget analysis with conductive and radiated over‐the‐air measurements. The results indicate that the implemented radio solution is able to achieve the target key performance indicator, namely, a 2.5 Gbps data rate on average, over a range of up to 200 m.

Type of iconicity matters in the vocabulary development of signing children

NARCIS (Netherlands)

Ortega, G.; Sümer, B.; Özyürek, A.

2017-01-01

Recent research on signed as well as spoken language shows that the iconic features of the target language might play a role in language development. Here, we ask further whether different types of iconic depictions modulate children's preferences for certain types of sign-referent links during

Link-quality measurement and reporting in wireless sensor networks.

Science.gov (United States)

Chehri, Abdellah; Jeon, Gwanggil; Choi, Byoungjo

2013-03-04

Wireless Sensor networks (WSNs) are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

Link-Quality Measurement and Reporting in Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Byoungjo Choi

2013-03-01

Full Text Available Wireless Sensor networks (WSNs are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

Low complexity source and channel coding for mm-wave hybrid fiber-wireless links

DEFF Research Database (Denmark)

Lebedev, Alexander; Vegas Olmos, Juan José; Pang, Xiaodan

2014-01-01

We report on the performance of channel and source coding applied for an experimentally realized hybrid fiber-wireless W-band link. Error control coding performance is presented for a wireless propagation distance of 3 m and 20 km fiber transmission. We report on peak signal-to-noise ratio perfor...

Minimizing SIP Session Re-Setup Delay over Wireless Link in 3G Handover Scenarios

Directory of Open Access Journals (Sweden)

Moon Bongkyo

2010-01-01

Full Text Available The delay in transmitting SIP messages over the wireless link for session resetup at handover is still major bottleneck for interactive multimedia service. In this paper, a proxy agent-based scheme is proposed to minimize the SIP session setup delay over a wireless link in 3G inter-subnet handover scenarios. This scheme is based on the two characteristics. One is that the major factor of SIP session re-setup delay is generally caused by the retransmissions in the unreliable wireless links, and the other is that most of the fields in request messages as well as response messages are duplicated when a set of SIP messages are exchanged during session re-setup procedure. In this scheme, no change is required in the SIP message processing except for the proxy agents in both BS and MH.

Optical wireless link between a nanoscale antenna and a transducing rectenna.

Science.gov (United States)

Dasgupta, Arindam; Mennemanteuil, Marie-Maxime; Buret, Mickaël; Cazier, Nicolas; Colas-des-Francs, Gérard; Bouhelier, Alexandre

2018-05-18

Initiated as a cable-replacement solution, short-range wireless power transfer has rapidly become ubiquitous in the development of modern high-data throughput networking in centimeter to meter accessibility range. Wireless technology is now penetrating a higher level of system integration for chip-to-chip and on-chip radiofrequency interconnects. However, standard CMOS integrated millimeter-wave antennas have typical size commensurable with the operating wavelength, and are thus an unrealistic solution for downsizing transmitters and receivers to the micrometer and nanometer scale. Herein, we demonstrate a light-in and electrical signal-out, on-chip wireless near-infrared link between a 220 nm optical antenna and a sub-nanometer rectifying antenna converting the transmitted optical energy into direct electrical current. The co-integration of subwavelength optical functional devices with electronic transduction offers a disruptive solution to interface photons and electrons at the nanoscale for on-chip wireless optical interconnects.

Bidirectional 3.125 Gbps downstream / 2 Gbps upstream impulse radio ultrawide-band (UWB) over combined fiber and wireless link

DEFF Research Database (Denmark)

Jensen, Jesper Bevensee; Gibbon, Timothy Braidwood; Yu, Xianbin

2010-01-01

We demonstrate bidirectional fiber and wireless transmission of impulse radio ultra-wideband at 3.125 Gbps downstream and 2 Gbps upstream. After transmission over 50 km fiber and 1.85 m wireless link both signals are recovered without errors.......We demonstrate bidirectional fiber and wireless transmission of impulse radio ultra-wideband at 3.125 Gbps downstream and 2 Gbps upstream. After transmission over 50 km fiber and 1.85 m wireless link both signals are recovered without errors....

The road to language learning is iconic: evidence from British Sign Language.

Science.gov (United States)

Thompson, Robin L; Vinson, David P; Woll, Bencie; Vigliocco, Gabriella

2012-12-01

An arbitrary link between linguistic form and meaning is generally considered a universal feature of language. However, iconic (i.e., nonarbitrary) mappings between properties of meaning and features of linguistic form are also widely present across languages, especially signed languages. Although recent research has shown a role for sign iconicity in language processing, research on the role of iconicity in sign-language development has been mixed. In this article, we present clear evidence that iconicity plays a role in sign-language acquisition for both the comprehension and production of signs. Signed languages were taken as a starting point because they tend to encode a higher degree of iconic form-meaning mappings in their lexicons than spoken languages do, but our findings are more broadly applicable: Specifically, we hypothesize that iconicity is fundamental to all languages (signed and spoken) and that it serves to bridge the gap between linguistic form and human experience.

Wireless link using on-chip photonic integrated millimeter-wave sources

NARCIS (Netherlands)

Guzmán, R. C.; Gordón, C.; Carpintero, G.; Leijtens, X.; Lawniczak, Katarzyna

2015-01-01

Over the last few years wireless link data traffic has drastically increased due to a change in the way today's society creates, shares, and consumes information. Millimeter-waves (30-300 GHz) have a great advantage due to the wide bandwidths available for carrying information, enabling broadband

Wireless Energy and Information Transmission in FSO and RF-FSO Links

KAUST Repository

Makki, Behrooz; Svensson, Tommy; Buisman, Koen; Perez, Joaquin; Alouini, Mohamed-Slim

2017-01-01

We propose and analyze a wireless energy and information transmission scheme in free-space optical (FSO) links. The results are presented for both quasi-static and fast-fading conditions. We derive closed-form expressions for throughput, outage

Full-duplex bidirectional transmission of 10-Gb/s millimeter-wave QPSK signal in E-band optical wireless link.

Science.gov (United States)

Fang, Yuan; Yu, Jianjun; Chi, Nan; Xiao, Jiangnan

2014-01-27

We experimentally demonstrated full-duplex bidirectional transmission of 10-Gb/s millimeter-wave (mm-wave) quadrature phase shift keying (QPSK) signal in E-band (71-76 GHz and 81-86 GHz) optical wireless link. Single-mode fibers (SMF) are connected at both sides of the antenna for uplink and downlink which realize 40-km SMF and 2-m wireless link for bidirectional transmission simultaneously. We utilized multi-level modulation format and coherent detection in such E-band optical wireless link for the first time. Mm-wave QPSK signal is generated by photonic technique to increase spectrum efficiency and received signal is coherently detected to improve receiver sensitivity. After the coherent detection, digital signal processing is utilized to compensate impairments of devices and transmission link.

Energy Efficient Link Aware Routing with Power Control in Wireless Ad Hoc Networks.

Science.gov (United States)

Katiravan, Jeevaa; Sylvia, D; Rao, D Srinivasa

2015-01-01

In wireless ad hoc networks, the traditional routing protocols make the route selection based on minimum distance between the nodes and the minimum number of hop counts. Most of the routing decisions do not consider the condition of the network such as link quality and residual energy of the nodes. Also, when a link failure occurs, a route discovery mechanism is initiated which incurs high routing overhead. If the broadcast nature and the spatial diversity of the wireless communication are utilized efficiently it becomes possible to achieve improvement in the performance of the wireless networks. In contrast to the traditional routing scheme which makes use of a predetermined route for packet transmission, such an opportunistic routing scheme defines a predefined forwarding candidate list formed by using single network metrics. In this paper, a protocol is proposed which uses multiple metrics such as residual energy and link quality for route selection and also includes a monitoring mechanism which initiates a route discovery for a poor link, thereby reducing the overhead involved and improving the throughput of the network while maintaining network connectivity. Power control is also implemented not only to save energy but also to improve the network performance. Using simulations, we show the performance improvement attained in the network in terms of packet delivery ratio, routing overhead, and residual energy of the network.

Energy Efficient Link Aware Routing with Power Control in Wireless Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Jeevaa Katiravan

2015-01-01

Full Text Available In wireless ad hoc networks, the traditional routing protocols make the route selection based on minimum distance between the nodes and the minimum number of hop counts. Most of the routing decisions do not consider the condition of the network such as link quality and residual energy of the nodes. Also, when a link failure occurs, a route discovery mechanism is initiated which incurs high routing overhead. If the broadcast nature and the spatial diversity of the wireless communication are utilized efficiently it becomes possible to achieve improvement in the performance of the wireless networks. In contrast to the traditional routing scheme which makes use of a predetermined route for packet transmission, such an opportunistic routing scheme defines a predefined forwarding candidate list formed by using single network metrics. In this paper, a protocol is proposed which uses multiple metrics such as residual energy and link quality for route selection and also includes a monitoring mechanism which initiates a route discovery for a poor link, thereby reducing the overhead involved and improving the throughput of the network while maintaining network connectivity. Power control is also implemented not only to save energy but also to improve the network performance. Using simulations, we show the performance improvement attained in the network in terms of packet delivery ratio, routing overhead, and residual energy of the network.

Wireless Energy and Information Transmission in FSO and RF-FSO Links

KAUST Repository

Makki, Behrooz

2017-09-22

We propose and analyze a wireless energy and information transmission scheme in free-space optical (FSO) links. The results are presented for both quasi-static and fast-fading conditions. We derive closed-form expressions for throughput, outage probability and optimal power allocation optimizing the system throughput/outage probability. Finally, we complement the FSO link with an additional radio frequency (RF) link to create a hybrid RF-FSO system and reduce the system outage probability. The results show that joint implementation of the RF and FSO links leads to considerable performance improvement, compared to the cases with only FSO-based communication.

An Accurate Link Correlation Estimator for Improving Wireless Protocol Performance

Science.gov (United States)

Zhao, Zhiwei; Xu, Xianghua; Dong, Wei; Bu, Jiajun

2015-01-01

Wireless link correlation has shown significant impact on the performance of various sensor network protocols. Many works have been devoted to exploiting link correlation for protocol improvements. However, the effectiveness of these designs heavily relies on the accuracy of link correlation measurement. In this paper, we investigate state-of-the-art link correlation measurement and analyze the limitations of existing works. We then propose a novel lightweight and accurate link correlation estimation (LACE) approach based on the reasoning of link correlation formation. LACE combines both long-term and short-term link behaviors for link correlation estimation. We implement LACE as a stand-alone interface in TinyOS and incorporate it into both routing and flooding protocols. Simulation and testbed results show that LACE: (1) achieves more accurate and lightweight link correlation measurements than the state-of-the-art work; and (2) greatly improves the performance of protocols exploiting link correlation. PMID:25686314

Integration and analysis of neighbor discovery and link quality estimation in wireless sensor networks.

Science.gov (United States)

Radi, Marjan; Dezfouli, Behnam; Abu Bakar, Kamalrulnizam; Abd Razak, Shukor

2014-01-01

Network connectivity and link quality information are the fundamental requirements of wireless sensor network protocols to perform their desired functionality. Most of the existing discovery protocols have only focused on the neighbor discovery problem, while a few number of them provide an integrated neighbor search and link estimation. As these protocols require a careful parameter adjustment before network deployment, they cannot provide scalable and accurate network initialization in large-scale dense wireless sensor networks with random topology. Furthermore, performance of these protocols has not entirely been evaluated yet. In this paper, we perform a comprehensive simulation study on the efficiency of employing adaptive protocols compared to the existing nonadaptive protocols for initializing sensor networks with random topology. In this regard, we propose adaptive network initialization protocols which integrate the initial neighbor discovery with link quality estimation process to initialize large-scale dense wireless sensor networks without requiring any parameter adjustment before network deployment. To the best of our knowledge, this work is the first attempt to provide a detailed simulation study on the performance of integrated neighbor discovery and link quality estimation protocols for initializing sensor networks. This study can help system designers to determine the most appropriate approach for different applications.

Integration and Analysis of Neighbor Discovery and Link Quality Estimation in Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Marjan Radi

2014-01-01

Full Text Available Network connectivity and link quality information are the fundamental requirements of wireless sensor network protocols to perform their desired functionality. Most of the existing discovery protocols have only focused on the neighbor discovery problem, while a few number of them provide an integrated neighbor search and link estimation. As these protocols require a careful parameter adjustment before network deployment, they cannot provide scalable and accurate network initialization in large-scale dense wireless sensor networks with random topology. Furthermore, performance of these protocols has not entirely been evaluated yet. In this paper, we perform a comprehensive simulation study on the efficiency of employing adaptive protocols compared to the existing nonadaptive protocols for initializing sensor networks with random topology. In this regard, we propose adaptive network initialization protocols which integrate the initial neighbor discovery with link quality estimation process to initialize large-scale dense wireless sensor networks without requiring any parameter adjustment before network deployment. To the best of our knowledge, this work is the first attempt to provide a detailed simulation study on the performance of integrated neighbor discovery and link quality estimation protocols for initializing sensor networks. This study can help system designers to determine the most appropriate approach for different applications.

Defining popular iconic metaphor.

Science.gov (United States)

Columbus, Peter J; Boerger, Michael A

2002-04-01

Popular Iconic Metaphor is added to the cognitive linguistic lexicon of figurative language. Popular Iconic Metaphors employ real or fictional celebrities of popular culture as source domains in figurative discourse. Some borders of Popular Iconic Metaphor are identified, and Elvis Presley is offered as a prototype example of a popular iconic source domain, due to his ubiquity in American popular culture, which affords his figurative usage in ways consistent with decision heuristics in everyday life. Further study of Popular Iconic Metaphors may serve to illuminate how figurative expressions emerge in their localized contexts, structure conduct and experience, and affect mediation of cultural and personal meanings.

Generic icons – yes or no?

Directory of Open Access Journals (Sweden)

Krunoslav Bedi

2010-06-01

Full Text Available The information society has become increasingly dependant on programs that are subjected to frequent evolutive, basic and logical changes for a variety of reasons whereas the visual design of the program/program interface mostly remains the same or gets slightly modified. The development of technology has become to such an extent a commonplace that the use of redesigned programs implies icons that are visually acceptable although representing obsolete technologies and that are eventually hard to change due to the habits developed by the program users. The research presents a study into the personal preference as to a particular icon, “Save” for example, and into the perception of the visual identities of today's programs under the circumstance of program icons being not compliant with the technological state-of-the-art. Based on the obtained results, the survey that included students attending web design and media technician courses and ECDL course participants who come in contact with computers and programming tools for the first time should enlighten both teachers and designers of programming interfaces about the way of linking the formal knowledge with a constructivist approach to designing and redesigning programs.

0.4 THz Photonic-Wireless Link With 106 Gb/s Single Channel Bitrate

DEFF Research Database (Denmark)

Jia, Shi; Pang, Xiaodan; Ozolins, Oskars

2018-01-01

To accommodate the demand of exponentially increased global wireless data traffic, the prospective data rates for wireless communication in the market place will soon reach 100 Gb/s and beyond. In the lab environment, wireless transmission throughput has been elevated to the level of over 100 Gb....../s attributed to the development of photonic-assisted millimeter wave and terahertz (THz) technologies. However, most of recent demonstrations with over 100 Gb/s data rates are based on spatial or frequency division multiplexing techniques, resulting in increased system's complexity and energy consumption. Here......, we experimentally demonstrate a single channel 0.4 THz photonic-wireless link achieving a net data rate of beyond 100 Gb/s by using a single pair of THz emitter and receiver, without employing any spatial/frequency division multiplexing techniques. The high throughput up to 106 Gb/s within a single...

The Semantic Analysis of Icon

Directory of Open Access Journals (Sweden)

m Piravivanak

2012-03-01

Full Text Available "Eikon" (Greek word or "Imago" (Latin word signifies a kind of similarity or "likeness". In Plato’s philosophy, this term implies "likeness" of appearance to pattern or symbol. In semantic analysis of icon, which is correlated with Idea, we can find factors such as "perception", "imagination", "likeness", "imitation" (Mimesis, "imaginary ideas", that is, it is not possible to reduce icon to a material picture because it is supported by cultural (symbolic, perceptual and conceptual sources. The process in which an icon is established indicates a special relation between icon and imaginary ideas that is supported by symbolic sources. Then, it is not possible to regard icon as a material picture because icon is an icon of a symbol which is able to play its role visibly in relation to a symbol.

Congestion control in wireless links based on selective delivery of erroneous packets

DEFF Research Database (Denmark)

Korhonen, Jari; Perkis, Andrew; Reiter, Ulrich

2011-01-01

Traditionally, congestion control in packet networks is performed by reducing the transmission rate when congestion is detected, in order to cut down the traffic that overwhelms the capacity of the network. However, if the bottleneck is a wireless link, congestion is often cumulated because...... the performance of the proposed mechanism against traditional congestion control with a simulation study. The results show that the proposed approach can improve the overall performance both by increasing the throughput over the wireless and improving the video quality in terms of peak signal-to-noise ratio (PSNR...

The Link between Form and Meaning in British Sign Language: Effects of Iconicity for Phonological Decisions

Science.gov (United States)

Thompson, Robin L.; Vinson, David P.; Vigliocco, Gabriella

2010-01-01

Signed languages exploit the visual/gestural modality to create iconic expression across a wide range of basic conceptual structures in which the phonetic resources of the language are built up into an analogue of a mental image (Taub, 2001). Previously, we demonstrated a processing advantage when iconic properties of signs were made salient in a…

Iconic Memory

Science.gov (United States)

Sakitt, Barbara

1976-01-01

Describes a series of experiments showing that in normal subjects (a) iconic storage occurs primarily in the retina in the photoreceptors and (b) under conditions of dark pre- and postexposure fields, the icon is mainly a rod phenomenon. Draws conclusions based on these experiments, discusses previous work done by others, and attempts to reconcile…

THE STROGANOV OR OLD BELIEVERS’ ICON PAINTING TRADITION IN THE WORKS OF N.S. LESKOV

Directory of Open Access Journals (Sweden)

Yana Valeryevna Karsakova

2012-11-01

Full Text Available N.S. Leskov is known to have been a collector of icons and a connoisseur of history and techniques of icon painting. In his work as a writer he made use of his visual impression of icons painted in the old believers' tradition. Unlike modern scholars, when acting as an iconographer, Leskov did not classify old believers' icon painting as a separate trend, subsuming it within the “Stroganov school”. In the 19th century, the Stroganov school icons were distinguished by the mark of the Stroganov family name on the icon's reverse side. Such icons were believed to have been painted in the workshops officially set up by the Stroganov family. “An old believers' school icon” would be the one painted by at a workshop owned by old believers for the use in their prayer rooms or churches. Leskov's opinion on the insoluble link between the Stroganov and old believers' school of icon painting well agreed with the works of I.P. Sakharov the writer was quite familiar with, as well as with the ideas old believers themselves expressed concerning the history and traditions of icon painting. Leskov knew these opinions through communication with icon painters who professed the old belief version of Orthodox Christianity.

Iconic hyperlinks on e-commerce websites.

Science.gov (United States)

Cheng, Hong-In; Patterson, Patrick E

2007-01-01

The proper use of iconic interfaces reduces system complexity and helps users interact with systems more easily. However, due to carelessness, inadequate research, and the web's relatively short history, the icons used on web sites often are ambiguous. Because non-identifiable icons may convey meanings other than those intended, designers must consider whether icons are easily identifiable when creating web sites. In this study, visual icons used on e-business web sites were examined by population stereotypy and categorized into three groups: identifiable, medium, and vague. Representative icons from each group were tested by comparing selection performance in groups of student volunteers, with identifiable and medium icons improving performance. We found that only easily identifiable icons can reduce complexity and increase system usability.

Iconic decay in schizophrenia.

Science.gov (United States)

Hahn, Britta; Kappenman, Emily S; Robinson, Benjamin M; Fuller, Rebecca L; Luck, Steven J; Gold, James M

2011-09-01

Working memory impairment is considered a core deficit in schizophrenia, but the precise nature of this deficit has not been determined. Multiple lines of evidence implicate deficits at the encoding stage. During encoding, information is held in a precategorical sensory store termed iconic memory, a literal image of the stimulus with high capacity but rapid decay. Pathologically increased iconic decay could reduce the number of items that can be transferred into working memory before the information is lost and could thus contribute to the working memory deficit seen in the illness. The current study used a partial report procedure to test the hypothesis that patients with schizophrenia (n = 37) display faster iconic memory decay than matched healthy control participants (n = 28). Six letters, arranged in a circle, were presented for 50 ms. Following a variable delay of 0-1000 ms, a central arrow cue indicated the item to be reported. In both patients and control subjects, recall accuracy decreased with increasing cue delay, reflecting decay of the iconic representation of the stimulus array. Patients displayed impaired memory performance across all cue delays, consistent with an impairment in working memory, but the rate of iconic memory decay did not differ between patients and controls. This provides clear evidence against faster loss of iconic memory representations in schizophrenia, ruling out iconic decay as an underlying source of the working memory impairment in this population. Thus, iconic decay rate can be added to a growing list of unimpaired cognitive building blocks in schizophrenia.

Broadband nanophotonic wireless links and networks using on-chip integrated plasmonic antennas.

Science.gov (United States)

Yang, Yuanqing; Li, Qiang; Qiu, Min

2016-01-19

Owing to their high capacity and flexibility, broadband wireless communications have been widely employed in radio and microwave regimes, playing indispensable roles in our daily life. Their optical analogs, however, have not been demonstrated at the nanoscale. In this paper, by exploiting plasmonic nanoantennas, we demonstrate the complete design of broadband wireless links and networks in the realm of nanophotonics. With a 100-fold enhancement in power transfer superior to previous designs as well as an ultrawide bandwidth that covers the entire telecommunication wavelength range, such broadband nanolinks and networks are expected to pave the way for future optical integrated nanocircuits.

Energy Link Optimization in a Wireless Power Transfer Grid under Energy Autonomy Based on the Improved Genetic Algorithm

Directory of Open Access Journals (Sweden)

Zhihao Zhao

2016-08-01

Full Text Available In this paper, an optimization method is proposed for the energy link in a wireless power transfer grid, which is a regional smart microgrid comprised of distributed devices equipped with wireless power transfer technology in a certain area. The relevant optimization model of the energy link is established by considering the wireless power transfer characteristics and the grid characteristics brought in by the device repeaters. Then, a concentration adaptive genetic algorithm (CAGA is proposed to optimize the energy link. The algorithm avoided the unification trend by introducing the concentration mechanism and a new crossover method named forward order crossover, as well as the adaptive parameter mechanism, which are utilized together to keep the diversity of the optimization solution groups. The results show that CAGA is feasible and competitive for the energy link optimization in different situations. This proposed algorithm performs better than its counterparts in the global convergence ability and the algorithm robustness.

mm-Wave Hybrid Photonic Wireless Links for Ultra-High Speed Wireless Transmissions

DEFF Research Database (Denmark)

Rommel, Simon; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

Hybrid photonic-wireless transmission schemes in the mm-wave frequency range are promising candidates to enable the multi-gigabit per second data communications required from wireless and mobile networks of the 5th and future generations. Large FCC spectrum allocations for wireless transmission...

Energy-Efficient Link-Layer Jamming Attacks against Wireless Sensor Network MAC Protocols

NARCIS (Netherlands)

Law, Y.W.; van Hoesel, L.F.W.; Doumen, J.M.; Hartel, Pieter H.; Havinga, Paul J.M.; Atluri, V.; Samarati, P.; Ning, P.; Du, W.

2005-01-01

A typical wireless sensor node has little protection against radio jamming. The situation becomes worse if energy efficient jamming can be achieved by exploiting knowledge of the data link layer. Encrypting the packets may help prevent the jammer from taking actions based on the content of the

Modeling and Performance Analysis of 10 Gbps Inter-satellite Optical Wireless Communication Link

Science.gov (United States)

Singh, Mehtab

2017-12-01

Free-space optical (FSO) communication has the advantages of two of the most predominant data transmission technologies - optical fiber communication and wireless communication. Most of the technical aspects of FSO are similar to that of optical fiber communication, with major difference in the information signal propagation medium which is free space in case of FSO rather than silica glass in optical fiber communication. One of the most important applications of FSO is inter-satellite optical wireless communication (IsOWC) links which will be deployed in the future in space. The IsOWC links have many advantages over the previously existing microwave satellite communication technologies such as higher bandwidth, lower power consumption, low cost of implementation, light size, and weight. In this paper, modeling and performance analysis of a 10-Gbps inter-satellite communication link with two satellites separated at a distance of 1,200 km has been done using OPTISYSTEM simulation software. Performance has been analyzed on the basis of quality factor, signal to noise ratio (SNR), and total power of the received signal.

What makes icons appealing? The role of processing fluency in predicting icon appeal in different task contexts.

OpenAIRE

McDougall, S.; Reppa, I.; Kulik, J.; Taylor, A.

2016-01-01

Although icons appear on almost all interfaces, there is a paucity of research examining the determinants of icon appeal. The experiments reported here examined the icon characteristics determining appeal and the extent to which processing fluency - the subjective ease with which individuals process information - was used as a heuristic to guide appeal evaluations. Participants searched for, and identified, icons in displays. The initial appeal of icons was held constant while ease of process...

Real-time 2.5  Gbit/s spatial circuit switching on W-band wireless links

DEFF Research Database (Denmark)

Rodríguez, Sebastián; Morales Vicente, Alvaro; Gallardo, Omar

2017-01-01

A spatial circuit switching system based on a beam steering application for W-band wireless links is proposed and experimentally demonstrated. The system enables two simultaneous transmissions of a 2.5 Gbit∕s data signal over a carrier of 81 GHz, while allowing the receiver to dynamically switch...... between them. The performance of the system is tested with the real-time measurements of the BER, achieving values below the FEC limit for 7% of overhead and serving to prove the viability of wireless spatial circuit switching in the next generation of wireless access networks....

Smart Icon Cards

Science.gov (United States)

Dunbar, Laura

2015-01-01

Icons are frequently used in the music classroom to depict concepts in a developmentally appropriate way for students. SmartBoards provide music educators yet another way to share these manipulatives with students. This article provides a step-by-step tutorial to create Smart Icon Cards using the folk song "Lucy Locket."

High capacity hybrid optical fiber-wireless links in 75–300GHz band

DEFF Research Database (Denmark)

Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

2014-01-01

Seamless convergence of fiber-optic and the wireless networks is of great interest for enabling transparent delivery of broadband services to users in different locations, including both metropolitan and rural areas. Current demand of bandwidth by end-users, especially using mobile devices......, is seeding the need to use bands located at the millimeter-wave region (30–300 GHz), mainly because of its inherent broadband nature. In our lab, we have conducted extensive research on high-speed photonic-wireless links in the W-band (75–110GHz). In this paper, we will present our latest findings...

Optical-wireless-optical full link for polarization multiplexing quadrature amplitude/phase modulation signal transmission.

Science.gov (United States)

Li, Xinying; Yu, Jianjun; Chi, Nan; Zhang, Junwen

2013-11-15

We propose and experimentally demonstrate an optical wireless integration system at the Q-band, in which up to 40 Gb/s polarization multiplexing multilevel quadrature amplitude/phase modulation (PM-QAM) signal can be first transmitted over 20 km single-mode fiber-28 (SMF-28), then delivered over a 2 m 2 × 2 multiple-input multiple-output wireless link, and finally transmitted over another 20 km SMF-28. The PM-QAM modulated wireless millimeter-wave (mm-wave) signal at 40 GHz is generated based on the remote heterodyning technique, and demodulated by the radio-frequency transparent photonic technique based on homodyne coherent detection and baseband digital signal processing. The classic constant modulus algorithm equalization is used at the receiver to realize polarization demultiplexing of the PM-QAM signal. For the first time, to the best of our knowledge, we realize the conversion of the PM-QAM modulated wireless mm-wave signal to the optical signal as well as 20 km fiber transmission of the converted optical signal.

Topology control algorithm for wireless sensor networks based on Link forwarding

Science.gov (United States)

Pucuo, Cairen; Qi, Ai-qin

2018-03-01

The research of topology control could effectively save energy and increase the service life of network based on wireless sensor. In this paper, a arithmetic called LTHC (link transmit hybrid clustering) based on link transmit is proposed. It decreases expenditure of energy by changing the way of cluster-node’s communication. The idea is to establish a link between cluster and SINK node when the cluster is formed, and link-node must be non-cluster. Through the link, cluster sends information to SINK nodes. For the sake of achieving the uniform distribution of energy on the network, prolongate the network survival time, and improve the purpose of communication, the communication will cut down much more expenditure of energy for cluster which away from SINK node. In the two aspects of improving the traffic and network survival time, we find that the LTCH is far superior to the traditional LEACH by experiments.

30 pJ/b, 67 Mbps, Centimeter-to-Meter Range Data Telemetry With an IR-UWB Wireless Link.

Science.gov (United States)

Ebrazeh, Ali; Mohseni, Pedram

2015-06-01

This paper reports an energy-efficient, impulse radio ultra wideband (IR-UWB) wireless link operating in 3-5 GHz for data telemetry over centimeter-to-meter range distances at rates extended to tens of Mbps. The link comprises an all-digital, integrated transmitter (TX) fabricated in 90 nm 1P/9M CMOS that incorporates a waveform-synthesis pulse generator and a timing generator for on-off-keying (OOK) pulse modulation and phase scrambling. The link also incorporates an energy-detection receiver (RX) realized with commercial off-the-shelf (COTS) components that performs radio-frequency (RF) filtering, amplification, logarithmic power detection for data demodulation and automatic level control for robust operation in the presence of distance variations. Employing a miniaturized, UWB, chip antenna for the TX and RX, wireless transmission of pseudo-random binary sequence (PRBS) data at rates up to 50 Mbps over 10 cm-1 m is shown. Further, employing a high-gain horn antenna for the RX, wireless transmission of PRBS data at rates up to 67 Mbps over 50 cm-4 m is shown with a TX energy consumption of 30 pJ/b (i.e., power consumption of 2 mW) from 1.2 V. The measured bit error rate (BER) in both cases is wireless recording of the background current of a carbon-fiber microelectrode (CFM) in one fast-scan cyclic voltammetry (FSCV) scan using the IR-UWB link are also included, exhibiting excellent match with those obtained from a conventional frequency-shift-keyed (FSK) link at ~433 MHz.

Beyond Iconic Simulation

Science.gov (United States)

Dormans, Joris

2011-01-01

Realism remains a prominent topic in game design and industry research; yet, a strong academic case can be made that games are anything, but realistic. This article frames realism in games in semiotic terms as iconic simulation and argues that games can gain expressiveness when they move beyond the current focus on iconic simulation. In parallel…

Representations of God in Icons. Immanence and Transcendence in Christian Art

Directory of Open Access Journals (Sweden)

Isbasoiu Iulian

2016-03-01

Full Text Available Human desire to be in a more natural relationship with God, his Creator, caused the former to find different means of communication. In addition to the liturgical expression, materialized in prayer, another way of interaction is represented by the icon. The icon and through the icon, Heaven and earth, God and the members of the triumphant Church and the ones of the militant Church meet and communicate. The iconographic representation of God, symbols, events and holy Persons, gave rise to much controversy in history, which triggered a major conflict in the life of the Church, culminating in the eighth century iconoclastic dispute. The Seventh Ecumenical Council solved this dispute and placed the icon in its natural spiritual position. In the present study we will analyze and contrast how people have understood the freedom of representing the image of God the Father in icons, an issue which caused disputes and reactions due to exaggerations in artistic expression and misunderstandings linked to the limits of such representation. This evolution is considered historically in the Christian world, East and West, which shows either an exaggerated tolerance of representation or an extreme conservatism leading to the prohibition of painting an anthropomorphic image of the Father. We will also study the recommendations of in the textbooks of Christian erminia and we will present examples of Romanian iconographic art.

The 'icon' of output efficiency

International Nuclear Information System (INIS)

Bligh, L.N.; Evans, S.G.; Larcos, G.; Gruenewald, S.M.

1999-01-01

Full text: Output efficiency (OE) is a well-validated parameter used in the assessment of hydronephrosis. Current analysis on Microdelta appears to produce few low OE values and occasional inability to produce a result. We sought an OE program which gave a reliable response over the full range of values. The aims of this study were to determine: (1) whether OE results are comparable between two computer systems; (2) a normal range for OE on an ICON; (3) inter-observer reproducibility; and (4) the correlation between the two programs and the residual cortical activity ratio (RCA), an index which assesses tracer washout from the 20 min cortical activity/peak cortical activity. Accordingly, two blinded medical radiation scientists reviewed 41 kidneys (26 native, 15 transplant) and calculated OE for each kidney on the ICON and Microdelta computers The OE on the Microdelta and the ICON had good correspondence (r = 0.6%, SEE = 6.2). The extrapolated normal range for ICON OE was 69-92% (mean 80.9%). The inter-observer reproducibility on the ICON was excellent with a CV of 8.7%. ICON OE and RCA had a strong correlation (r = - 0.77, SEE = 0.09), compared with a weaker correlation for the Microdelta (r = 0.47, SEE = 0.13). Processing on the ICON was almost half that of the Microdelta at 4 min compared with 7 min. We conclude that OE generated by these computer programs has good correlation, an established normal range, excellent interobserver reproducibility, but differing correlation with RCA. The response of the ICON program to low ranges of OE is being investigated further

Securing the communication of medical information using local biometric authentication and commercial wireless links.

Science.gov (United States)

Ivanov, Vladimir I; Yu, Paul L; Baras, John S

2010-09-01

Medical information is extremely sensitive in nature - a compromise, such as eavesdropping or tampering by a malicious third party, may result in identity theft, incorrect diagnosis and treatment, and even death. Therefore, it is important to secure the transfer of medical information from the patient to the recording system. We consider a portable, wireless device transferring medical information to a remote server. We decompose this problem into two sub-problems and propose security solutions to each of them: (1) to secure the link between the patient and the portable device, and (2) to secure the link between the portable device and the network. Thus we push the limits of the network security to the edge by authenticating the user using their biometric information; authenticating the device to the network at the physical layer; and strengthening the security of the wireless link with a key exchange mechanism. The proposed authentication methods can be used for recording the readings of medical data in a central database and for accessing medical records in various settings.

Iconics: Icon Evolution in Digitality

Directory of Open Access Journals (Sweden)

Steven John Thompson

2010-11-01

Full Text Available Image manipulation, archiving, and sharing are all critical technological aspects of Western culture and postmodern civilization. Consequently, creation, identification, dissemination, and proliferation of powerful images across media channels today indicate a burgeoning area of information technology. While words alone are capable of conveying adequate information across media channels, the news industry crafts around the dual enterprise of both word and image. Audio-visual supports of these communication devices constituting new media are standard means of rhetorical expressions in acquiring and sharing information in daily life. Overwhelming sensory experiences associated with broadcast media ensure that neither 1 time to study individual factors that render media as iconic, nor 2 interest in interpretation of such dynamics prior to public release. That leads to deeper issues of access, privilege, and motive, yet only through serious scholarly inquiry can we gain understanding of rhetorical roots and expressions of the diverse entities producing media that eventually becomes iconic.

Experimental Performance Analysis of Wireless Links for Healthcare ...

African Journals Online (AJOL)

Wireless networking is currently being deployed for various applications. However, the application of wireless networking in healthcare remains a challenge mainly because of security and reliability concerns. This paper presents experimental results of performance analysis of a wireless network for healthcare application ...

Distributed and Cooperative Link Scheduling for Large-Scale Multihop Wireless Networks

Directory of Open Access Journals (Sweden)

Swami Ananthram

2007-01-01

Full Text Available A distributed and cooperative link-scheduling (DCLS algorithm is introduced for large-scale multihop wireless networks. With this algorithm, each and every active link in the network cooperatively calibrates its environment and converges to a desired link schedule for data transmissions within a time frame of multiple slots. This schedule is such that the entire network is partitioned into a set of interleaved subnetworks, where each subnetwork consists of concurrent cochannel links that are properly separated from each other. The desired spacing in each subnetwork can be controlled by a tuning parameter and the number of time slots specified for each frame. Following the DCLS algorithm, a distributed and cooperative power control (DCPC algorithm can be applied to each subnetwork to ensure a desired data rate for each link with minimum network transmission power. As shown consistently by simulations, the DCLS algorithm along with a DCPC algorithm yields significant power savings. The power savings also imply an increased feasible region of averaged link data rates for the entire network.

Distributed and Cooperative Link Scheduling for Large-Scale Multihop Wireless Networks

Directory of Open Access Journals (Sweden)

Ananthram Swami

2007-12-01

Full Text Available A distributed and cooperative link-scheduling (DCLS algorithm is introduced for large-scale multihop wireless networks. With this algorithm, each and every active link in the network cooperatively calibrates its environment and converges to a desired link schedule for data transmissions within a time frame of multiple slots. This schedule is such that the entire network is partitioned into a set of interleaved subnetworks, where each subnetwork consists of concurrent cochannel links that are properly separated from each other. The desired spacing in each subnetwork can be controlled by a tuning parameter and the number of time slots specified for each frame. Following the DCLS algorithm, a distributed and cooperative power control (DCPC algorithm can be applied to each subnetwork to ensure a desired data rate for each link with minimum network transmission power. As shown consistently by simulations, the DCLS algorithm along with a DCPC algorithm yields significant power savings. The power savings also imply an increased feasible region of averaged link data rates for the entire network.

Distortion-Based Link Adaptation for Wireless Video Transmission

Directory of Open Access Journals (Sweden)

Andrew Nix

2008-06-01

Full Text Available Wireless local area networks (WLANs such as IEEE 802.11a/g utilise numerous transmission modes, each providing different throughputs and reliability levels. Most link adaptation algorithms proposed in the literature (i maximise the error-free data throughput, (ii do not take into account the content of the data stream, and (iii rely strongly on the use of ARQ. Low-latency applications, such as real-time video transmission, do not permit large numbers of retransmission. In this paper, a novel link adaptation scheme is presented that improves the quality of service (QoS for video transmission. Rather than maximising the error-free throughput, our scheme minimises the video distortion of the received sequence. With the use of simple and local rate distortion measures and end-to-end distortion models at the video encoder, the proposed scheme estimates the received video distortion at the current transmission rate, as well as on the adjacent lower and higher rates. This allows the system to select the link-speed which offers the lowest distortion and to adapt to the channel conditions. Simulation results are presented using the MPEG-4/AVC H.264 video compression standard over IEEE 802.11g. The results show that the proposed system closely follows the optimum theoretic solution.

Wireless mesh networks.

Science.gov (United States)

Wang, Xinheng

2008-01-01

Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed.

Bandwidth enhancement of wireless optical communication link using a near-infrared laser over turbid underwater channel

KAUST Repository

Lee, It Ee; Guo, Yujian; Ng, Tien Khee; Park, Kihong; Alouini, Mohamed-Slim; Ooi, Boon S.

2017-01-01

Underwater wireless optical communication (UWOC) has been widely studied as a promising alternative to establish reliable short-range marine communication links. Microscopic particulates suspended in various ocean, harbor and natural waters

80 Gbit/s 16-QAM Multicarrier THz Wireless Communication Link in the 400 GHz Band

DEFF Research Database (Denmark)

Jia, Shi; Yu, Xianbin; Hu, Hao

2016-01-01

We experimentally demonstrate a high-speed multicarrier THz wireless communication system operating in the 400 GHz band. The use of spectrally efficient 16-QAM modulation and broadband THz transceivers enable link data rates up to 80 Gbit/s....

Fiber-wireless transmission system of 108  Gb/sdata over 80 km fiber and 2×2multiple-input multiple-output wireless links at 100 GHz W-band frequency.

Science.gov (United States)

Li, Xinying; Dong, Ze; Yu, Jianjun; Chi, Nan; Shao, Yufeng; Chang, G K

2012-12-15

We experimentally demonstrate a seamlessly integrated fiber-wireless system that delivers a 108  Gb/s signal through 80 km fiber and 1 m wireless transport over free space at 100 GHz adopting polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) modulation and heterodyning coherent detection. The X- and Y-polarization components of the optical PDM-QPSK baseband signal are simultaneously upconverted to 100 GHz wireless carrier by optical polarization-diversity heterodyne beating, and then independently transmitted and received by two pairs of transmitter and receiver antennas, which form a 2×2 multiple-input multiple-output wireless link. At the wireless receiver, two-stage downconversion is performed firstly in the analog domain based on balanced mixer and sinusoidal radio frequency signal, and then in the digital domain based on digital signal processing (DSP). Polarization demultiplexing is realized by the constant modulus algorithm in the DSP part at the receiver. The bit-error ratio for the 108  Gb/s PDM-QPSK signal is less than the pre-forward-error-correction threshold of 3.8×10(-3) after both 1 m wireless delivery at 100 GHz and 80 km single-mode fiber-28 transmission. To our knowledge, this is the first demonstration to realize 100  Gb/s signal delivery through both fiber and wireless links at 100 GHz.

16 Gb/s QPSK Wireless-over-Fibre Link in 75-110GHz Band Employing Optical Heterodyne Generation and Coherent Detection

DEFF Research Database (Denmark)

Zibar, Darko; Sambaraju, Rakesh; Caballero Jambrina, Antonio

2010-01-01

We report on the first demonstration of QPSK based Wireless-over-Fibre link in 75-110GHz band with a record capacity of up to 16Gb/s. Photonic wireless signal generation by heterodyne beating of free-running lasers and baud-rate digital coherent detection are employed....

Impact of a half-space interface on the wireless link between tiny sensor nodes

NARCIS (Netherlands)

Penkin, D.; Janssen, G.; Yarovoy, A.

2014-01-01

The power budget of a wireless link between two electrically small sensor nodes located close to an interface between two media is studied. The model includes both the propagation channel losses and input impedance of the radio frequency antennas. It is shown that a highly inductive half-space

Does Iconicity in Pictographs Matter? The Influence of Iconicity and Numeracy on Information Processing, Decision Making, and Liking in an Eye-Tracking Study.

Science.gov (United States)

Kreuzmair, Christina; Siegrist, Michael; Keller, Carmen

2017-03-01

Researchers recommend the use of pictographs in medical risk communication to improve people's risk comprehension and decision making. However, it is not yet clear whether the iconicity used in pictographs to convey risk information influences individuals' information processing and comprehension. In an eye-tracking experiment with participants from the general population (N = 188), we examined whether specific types of pictograph icons influence the processing strategy viewers use to extract numerical information. In addition, we examined the effect of iconicity and numeracy on probability estimation, recall, and icon liking. This experiment used a 2 (iconicity: blocks vs. restroom icons) × 2 (scenario: medical vs. nonmedical) between-subject design. Numeracy had a significant effect on information processing strategy, but we found no effect of iconicity or scenario. Results indicated that both icon types enabled high and low numerates to use their default way of processing and extracting the gist of the message from the pictorial risk communication format: high numerates counted icons, whereas low numerates used large-area processing. There was no effect of iconicity in the probability estimation. However, people who saw restroom icons had a higher probability of correctly recalling the exact risk level. Iconicity had no effect on icon liking. Although the effects are small, our findings suggest that person-like restroom icons in pictographs seem to have some advantages for risk communication. Specifically, in nonpersonalized prevention brochures, person-like restroom icons may maintain reader motivation for processing the risk information. © 2016 Society for Risk Analysis.

Opportunities and challenges for optical wireless: the competitive advantage of free space telecommunications links in today's crowded marketplace

Science.gov (United States)

Carbonneau, Theresa H.; Wisely, David R.

1998-01-01

Never before has the opportunity for terrestrial optical wireless communications links been so great. The high data rates attainable, up to OC-24, make it a very attractive and cost effective alternative to traditional fiber optic and microwave links. With today's demand for interactive multimedia-based applications, such as video conferencing and telemedicine, optical wireless products are the only ones that can provide the needed bandwidth in situations when it is too costly or impossible to install fiber optic cable. Recent developments in laser and optics technologies, in addition to auto beam tracking, permit transmission units to achieve excellent performance rates in all weather conditions.

Iconic Memories Die a Sudden Death.

Science.gov (United States)

Pratte, Michael S

2018-06-01

Iconic memory is characterized by its large storage capacity and brief storage duration, whereas visual working memory is characterized by its small storage capacity. The limited information stored in working memory is often modeled as an all-or-none process in which studied information is either successfully stored or lost completely. This view raises a simple question: If almost all viewed information is stored in iconic memory, yet one second later most of it is completely absent from working memory, what happened to it? Here, I characterized how the precision and capacity of iconic memory changed over time and observed a clear dissociation: Iconic memory suffered from a complete loss of visual items, while the precision of items retained in memory was only marginally affected by the passage of time. These results provide new evidence for the discrete-capacity view of working memory and a new characterization of iconic memory decay.

Digital Photonic Receivers for Wireless and Wireline Optical Fiber Transmission Links

DEFF Research Database (Denmark)

Guerrero Gonzalez, Neil

services. The experimental demonstration supported the following transmissions systems: a baseband, 5 Gbps, intensity modulation system employing a directly modulated vertical cavity surface emitting laser (VCSEL), a baseband 20 Gbps non-return-to-zero quadrature phase-shift keying (NRZ-QPSK) system...... receivers in hybrid wireless and wireline optical fiber transmission links. Furthermore, the digital signal processing framework presented in this thesis can be extended to design probabilistic-based digital photonic receivers that can find applications in cognitive heterogeneous reconfigurable optical...

Malala and the politics of global iconicity.

Science.gov (United States)

Olesen, Thomas

2016-06-01

The article presents a case analysis of Malala Yousafzai's transformation into a global injustice icon after she was shot in 2012 by the Pakistani Taliban for advocating for girls' right to education. The analysis focuses on the political aspects of this process and is divided into three parts. The first looks at factors that facilitated Malala's iconization as she was undergoing medical treatment and was unable to participate in her iconization. The second part starts when Malala enters the global public sphere and begins to actively contribute to the iconization process. The third part identifies de-iconizing resistance to Malala from Pakistani actors who see her iconization as a symbolic colonization in which Malala has become a vehicle of the West. Theoretically, the article is located within cultural sociology, but expands it in a political and global direction. © London School of Economics and Political Science 2016.

Frequency-division multiplexer and demultiplexer for terahertz wireless links.

Science.gov (United States)

Ma, Jianjun; Karl, Nicholas J; Bretin, Sara; Ducournau, Guillaume; Mittleman, Daniel M

2017-09-28

The development of components for terahertz wireless communications networks has become an active and growing research field. However, in most cases these components have been studied using a continuous or broadband-pulsed terahertz source, not using a modulated data stream. This limitation may mask important aspects of the performance of the device in a realistic system configuration. We report the characterization of one such device, a frequency multiplexer, using modulated data at rates up to 10 gigabits per second. We also demonstrate simultaneous error-free transmission of two signals at different carrier frequencies, with an aggregate data rate of 50 gigabits per second. We observe that the far-field spatial variation of the bit error rate is different from that of the emitted power, due to a small nonuniformity in the angular detection sensitivity. This is likely to be a common feature of any terahertz communication system in which signals propagate as diffracting beams not omnidirectional broadcasts.There is growing interest in the development of components to facilitate wireless communications in the terahertz but the characterization of these systems involve an unmodulated input. Here the authors demonstrate multiplexing and demultiplexing of data streams in the terahertz range using a real data link.

Link-state-estimation-based transmission power control in wireless body area networks.

Science.gov (United States)

Kim, Seungku; Eom, Doo-Seop

2014-07-01

This paper presents a novel transmission power control protocol to extend the lifetime of sensor nodes and to increase the link reliability in wireless body area networks (WBANs). We first experimentally investigate the properties of the link states using the received signal strength indicator (RSSI). We then propose a practical transmission power control protocol based on both short- and long-term link-state estimations. Both the short- and long-term link-state estimations enable the transceiver to adapt the transmission power level and target the RSSI threshold range, respectively, to simultaneously satisfy the requirements of energy efficiency and link reliability. Finally, the performance of the proposed protocol is experimentally evaluated in two experimental scenarios-body posture change and dynamic body motion-and compared with the typical WBAN transmission power control protocols, a real-time reactive scheme, and a dynamic postural position inference mechanism. From the experimental results, it is found that the proposed protocol increases the lifetime of the sensor nodes by a maximum of 9.86% and enhances the link reliability by reducing the packet loss by a maximum of 3.02%.

Combined Rate and Power Allocation with Link Scheduling in Wireless Data Packet Relay Networks with Fading Channels

Directory of Open Access Journals (Sweden)

Subhrakanti Dey

2007-08-01

Full Text Available We consider a joint rate and power control problem in a wireless data traffic relay network with fading channels. The optimization problem is formulated in terms of power and rate selection, and link transmission scheduling. The objective is to seek high aggregate utility of the relay node when taking into account buffer load management and power constraints. The optimal solution for a single transmitting source is computed by a two-layer dynamic programming algorithm which leads to optimal power, rate, and transmission time allocation at the wireless links. We further consider an optimal power allocation problem for multiple transmitting sources in the same framework. Performances of the resource allocation algorithms including the effect of buffer load control are illustrated via extensive simulation studies.

Novel Concepts of Cooperative Wireless Networking

DEFF Research Database (Denmark)

Zhang, Qi

2008-01-01

; secondly, the increasing density of the wireless devices makes cooperation possible; last, the cost of information exchange (i.e. transmission power, transmission time, spectrum, etc.) is very low if information exchange over short-range link is needed. Cooperation changes the way of information delivery......Although wireless networks have achieved great success in the lastest two decades, the current wireless networks have difficulties to fulll users' ever-increasing expectations and needs. It is mainly due to available spectrum resource scarcity, limited battery capacity of wireless device......, unreliable wireless radio link, etc. To tackle these issues, a new telecommunication paradigm has been proposed, referred to as cooperative wireless networking [1]. The basic idea of cooperative wireless networking is that wireless devices work together to achieve their individual goals or one common goal...

Characterization of In-Body to On-Body Wireless Radio Frequency Link for Upper Limb Prostheses.

Directory of Open Access Journals (Sweden)

Antonietta Stango

Full Text Available Wireless implanted devices can be used to interface patients with disabilities with the aim of restoring impaired motor functions. Implanted devices that record and transmit electromyographic (EMG signals have been applied for the control of active prostheses. This simulation study investigates the propagation losses and the absorption rate of a wireless radio frequency link for in-to-on body communication in the medical implant communication service (MICS frequency band to control myoelectric upper limb prostheses. The implanted antenna is selected and a suitable external antenna is designed. The characterization of both antennas is done by numerical simulations. A heterogeneous 3D body model and a 3D electromagnetic solver have been used to model the path loss and to characterize the specific absorption rate (SAR. The path loss parameters were extracted and the SAR was characterized, verifying the compliance with the guideline limits. The path loss model has been also used for a preliminary link budget analysis to determine the feasibility of such system compliant with the IEEE 802.15.6 standard. The resulting link margin of 11 dB confirms the feasibility of the system proposed.

Iconic memory requires attention

OpenAIRE

Persuh, Marjan; Genzer, Boris; Melara, Robert D.

2012-01-01

Two experiments investigated whether attention plays a role in iconic memory, employing either a change detection paradigm (Experiment 1) or a partial-report paradigm (Experiment 2). In each experiment, attention was taxed during initial display presentation, focusing the manipulation on consolidation of information into iconic memory, prior to transfer into working memory. Observers were able to maintain high levels of performance (accuracy of change detection or categorization) even when co...

Iconicity can ground the creation of vocal symbols.

Science.gov (United States)

Perlman, Marcus; Dale, Rick; Lupyan, Gary

2015-08-01

Studies of gestural communication systems find that they originate from spontaneously created iconic gestures. Yet, we know little about how people create vocal communication systems, and many have suggested that vocalizations do not afford iconicity beyond trivial instances of onomatopoeia. It is unknown whether people can generate vocal communication systems through a process of iconic creation similar to gestural systems. Here, we examine the creation and development of a rudimentary vocal symbol system in a laboratory setting. Pairs of participants generated novel vocalizations for 18 different meanings in an iterative 'vocal' charades communication game. The communicators quickly converged on stable vocalizations, and naive listeners could correctly infer their meanings in subsequent playback experiments. People's ability to guess the meanings of these novel vocalizations was predicted by how close the vocalization was to an iconic 'meaning template' we derived from the production data. These results strongly suggest that the meaningfulness of these vocalizations derived from iconicity. Our findings illuminate a mechanism by which iconicity can ground the creation of vocal symbols, analogous to the function of iconicity in gestural communication systems.

An asymmetric resonant coupling wireless power transmission link for Micro-Ball Endoscopy.

Science.gov (United States)

Sun, Tianjia; Xie, Xiang; Li, Guolin; Gu, Yingke; Deng, Yangdong; Wang, Ziqiang; Wang, Zhihua

2010-01-01

This paper investigates the design and optimization of a wireless power transmission link targeting Micro-Ball Endoscopy applications. A novel asymmetric resonant coupling structure is proposed to deliver power to an endoscopic Micro-Ball system for image read-out after it is excreted. Such a technology enables many key medical applications with stringent requirements for small system volume and high power delivery efficiency. A prototyping power transmission sub-system of the Micro-Ball system was implemented. It consists of primary coil, middle resonant coil, and cube-like full-direction secondary receiving coils. Our experimental results proved that 200mW of power can be successfully delivered. Such a wireless power transmission capability could satisfy the requirements of the Micro-Ball based endoscopy application. The transmission efficiency is in the range of 41% (worst working condition) to 53% (best working condition). Comparing to conventional structures, Asymmetric Resonant Coupling Structure improves power efficiency by 13%.

Voluntary eyeblinks disrupt iconic memory.

Science.gov (United States)

Thomas, Laura E; Irwin, David E

2006-04-01

In the present research, we investigated whether eyeblinks interfere with cognitive processing. In Experiment 1, the participants performed a partial-report iconic memory task in which a letter array was presented for 106 msec, followed 50, 150, or 750 msec later by a tone that cued recall of onerow of the array. At a cue delay of 50 msec between array offset and cue onset, letter report accuracy was lower when the participants blinked following array presentation than under no-blink conditions; the participants made more mislocation errors under blink conditions. This result suggests that blinking interferes with the binding of object identity and object position in iconic memory. Experiment 2 demonstrated that interference due to blinks was not due merely to changes in light intensity. Experiments 3 and 4 demonstrated that other motor responses did not interfere with iconic memory. We propose a new phenomenon, cognitive blink suppression, in which blinking inhibits cognitive processing. This phenomenon may be due to neural interference. Blinks reduce activation in area V1, which may interfere with the representation of information in iconic memory.

Iconic Decay in Schizophrenia

OpenAIRE

Hahn, Britta; Kappenman, Emily S.; Robinson, Benjamin M.; Fuller, Rebecca L.; Luck, Steven J.; Gold, James M.

2010-01-01

Working memory impairment is considered a core deficit in schizophrenia, but the precise nature of this deficit has not been determined. Multiple lines of evidence implicate deficits at the encoding stage. During encoding, information is held in a precategorical sensory store termed iconic memory, a literal image of the stimulus with high capacity but rapid decay. Pathologically increased iconic decay could reduce the number of items that can be transferred into working memory before the info...

Iconic memory requires attention.

Science.gov (United States)

Persuh, Marjan; Genzer, Boris; Melara, Robert D

2012-01-01

Two experiments investigated whether attention plays a role in iconic memory, employing either a change detection paradigm (Experiment 1) or a partial-report paradigm (Experiment 2). In each experiment, attention was taxed during initial display presentation, focusing the manipulation on consolidation of information into iconic memory, prior to transfer into working memory. Observers were able to maintain high levels of performance (accuracy of change detection or categorization) even when concurrently performing an easy visual search task (low load). However, when the concurrent search was made difficult (high load), observers' performance dropped to almost chance levels, while search accuracy held at single-task levels. The effects of attentional load remained the same across paradigms. The results suggest that, without attention, participants consolidate in iconic memory only gross representations of the visual scene, information too impoverished for successful detection of perceptual change or categorization of features.

Iconic memory requires attention

Directory of Open Access Journals (Sweden)

Marjan ePersuh

2012-05-01

Full Text Available Two experiments investigated whether attention plays a role in iconic memory, employing either a change-detection paradigm (Experiment 1 or a partial-report paradigm (Experiment 2. In each experiment, attention was taxed during initial display presentation, focusing the manipulation on consolidation of information into iconic memory, prior to transfer into working memory. Observers were able to maintain high levels of performance (accuracy of change detection or categorization even when concurrently performing an easy visual search task (low load. However, when the concurrent search was made difficult (high load, observers’ performance dropped to almost chance levels, while search accuracy held at single-task levels. The effects of attentional load remained the same across paradigms. The results suggest that, without attention, participants consolidate in iconic memory only gross representations of the visual scene, information too impoverished for successful detection of perceptual change or categorization of features.

Decay of Iconic Memory Traces Is Related to Psychometric Intelligence: A Fixed-Links Modeling Approach

Science.gov (United States)

Miller, Robert; Rammsayer, Thomas H.; Schweizer, Karl; Troche, Stefan J.

2010-01-01

Several memory processes have been examined regarding their relation to psychometric intelligence with the exception of sensory memory. This study examined the relation between decay of iconic memory traces, measured with a partial-report task, and psychometric intelligence, assessed with the Berlin Intelligence Structure test, in 111…

Dating of ancient icons from Kiev art collections

NARCIS (Netherlands)

Kovalyukh, N; van der Plicht, J; Possnert, G; Skripkin, [No Value; Chlenova, L; Boaretto, E.; Carmi, I.

2001-01-01

Icon painting in the Ukraine is rooted in the Byzantine culture, after the conversion to the Christian religion. During the medieval epoch, Kiev became the artistic center for highly skilled icon painters. The icons were painted on wooden boards, specially made for this purpose. Historic dating of

Classification of iconic images

OpenAIRE

Zrianina, Mariia; Kopf, Stephan

2016-01-01

Iconic images represent an abstract topic and use a presentation that is intuitively understood within a certain cultural context. For example, the abstract topic “global warming” may be represented by a polar bear standing alone on an ice floe. Such images are widely used in media and their automatic classification can help to identify high-level semantic concepts. This paper presents a system for the classification of iconic images. It uses a variation of the Bag of Visual Words approach wi...

Compact wideband CMOS receiver frontends for wireless communication

NARCIS (Netherlands)

Blaakmeer, S.C.

2010-01-01

Abstract Wireless communication is an integral part of our daily life, the mobile phone is an example of a very popular wireless communication device. A communication link consists of a transmitter, a receiver and the transmission medium, which air or vacuum for a wireless link. Part of the receiver

Comprehension of iconic gestures by chimpanzees and human children.

Science.gov (United States)

Bohn, Manuel; Call, Josep; Tomasello, Michael

2016-02-01

Iconic gestures-communicative acts using hand or body movements that resemble their referent-figure prominently in theories of language evolution and development. This study contrasted the abilities of chimpanzees (N=11) and 4-year-old human children (N=24) to comprehend novel iconic gestures. Participants learned to retrieve rewards from apparatuses in two distinct locations, each requiring a different action. In the test, a human adult informed the participant where to go by miming the action needed to obtain the reward. Children used the iconic gestures (more than arbitrary gestures) to locate the reward, whereas chimpanzees did not. Some children also used arbitrary gestures in the same way, but only after they had previously shown comprehension for iconic gestures. Over time, chimpanzees learned to associate iconic gestures with the appropriate location faster than arbitrary gestures, suggesting at least some recognition of the iconicity involved. These results demonstrate the importance of iconicity in referential communication. Copyright © 2015 Elsevier Inc. All rights reserved.

Symmetric Link Key Management for Secure Neighbor Discovery in a Decentralized Wireless Sensor Network

Science.gov (United States)

2017-09-01

KEY MANAGEMENT FOR SECURE NEIGHBOR DISCOVERY IN A DECENTRALIZED WIRELESS SENSOR NETWORK by Kelvin T. Chew September 2017 Thesis Advisor...and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT...DATE September 2017 3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE SYMMETRIC LINK KEY MANAGEMENT FOR SECURE NEIGHBOR

The Wireless ATM Architecture

Directory of Open Access Journals (Sweden)

R. Palitefka

1998-06-01

Full Text Available An overview of the proposed wireless ATM structure is provided. Wireless communication have been developed to a level where offered services can now be extended beyond voice and data. There are already wireless LANs, cordless systems offering data services and mobile data. Wireless LAN systems are basically planned for local, on-promises and in-house networking providing short distance radio or infrared links between computer system. The main challenge of wireless ATM is to harmonise the development of broadband wireless system with service B -ISDN/ATM and ATM LANs, and offer multimedia multiservice features for the support of time-sensitive voice communication, video, desktop multimedia applications, and LAN data traffic for the wireless user.

Design and Iconic Brands

Directory of Open Access Journals (Sweden)

2015-11-01

Full Text Available The VW Beetle, Apple, Porsche … many iconic brands have reached their status with groundbreaking designs. But what makes these designs so special? And is it really the design factor that accounts for the overall success of a brand? Dr. Walter de Silva shares with us his thoughts on iconic designs, the design process and the role of design in branding. Open your heart and mind to his extensive experience in developing designs for Volkswagen, Audi and other brands of the Volkswagen Group

Introduction to wireless sensor networks

CERN Document Server

Forster, Anna

2016-01-01

Explores real-world wireless sensor network development, deployment, and applications. The book begins with an introduction to wireless sensor networks and their fundamental concepts. Hardware components, operating systems, protocols, and algorithms that make up the anatomy of a sensor node are described in chapter two. Properties of wireless communications, medium access protocols, wireless links, and link estimation protocols are described in chapter three and chapter four. Routing basics and metrics, clustering techniques, time synchronization and localization protocols, as well as sensing techniques are introduced in chapter five to nine. The concluding chapter summarizes the learnt methods and shows how to use them to deploy real-world sensor networks in a structured way.

Wireless coexistence and interference test method for low-power wireless sensor networks

NARCIS (Netherlands)

Serra, R.; Nabi, Majid

2015-01-01

Wireless sensor networks (WSNs) are being increasingly introduced for critical applications such as safety, security and health. One the main characteristic requirements of such networks are that they should function with relative low power. Therefore the wireless links are more vulnerable.

Truncated power control for improving TCP/IP performance over CDMA wireless links

DEFF Research Database (Denmark)

Cianca, Ernestina; Prasad, Ramjee; De Sanctis, Mauro

2005-01-01

The issue of the performance degradation of transmission control protocol/Internet Protocol (TCP/IP) over wireless links due to the presence of noncongestion-related packet losses has been addressed with a physical layer approach. The effectiveness of automatic repeat request techniques...... in enhancing TCP/IP performance depends on the tradeoff between frame transmission delay and residual errors after retransmissions. The paper shows how a truncated power control can be effectively applied to improve that tradeoff so that a higher transmission reliability is provided without increasing...... the frame transmission delay through the radio link layer and without increasing the energy consumption. An analytical framework has been developed to show the feasibility and effectiveness of the proposed power control. The analytical results, which are carried out assuming a constant multiuser...

Media Morality and Visual Icons in the Age of Social Media

DEFF Research Database (Denmark)

Mortensen, Mette; Trenz, Hans-Jörg

2016-01-01

New and social media are increasingly used to raise issues of global justice. Images and texts representing distant suffering in an emotionally charged way involve users of social media in debates about ethical standards and moral responsibility. This raises the question of how social media users...... in fall 2015, which raised questions of distant spectatorship and moral responses with renewed urgency and immediacy. We consider the conditions of collective reception and interpretation of visual icons of human suffering, which became viral through social media in this period. We first situate social...... media reception in the framework for the analysis of moral spectatorship. We secondly explore the link between iconic images and the emergence of so-called impromptu publics of moral spectatorship. As an empirical case, we refer to the performance of reddit discussion groups in confronting the salient...

Limits to the usability of iconic memory.

Science.gov (United States)

Rensink, Ronald A

2014-01-01

Human vision briefly retains a trace of a stimulus after it disappears. This trace-iconic memory-is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report) of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alternating between visible and iconic representations. However, the duration over which it can be used depends on the type of task: some tasks can use iconic memory for at least 240 ms, others for only about 190 ms, while others for no more than about 120 ms. The existence of these different limits suggests that iconic memory may have multiple layers, each corresponding to a particular level of the visual hierarchy. In this view, the inability to use a layer of iconic memory may reflect an inability to maintain feedback connections to the corresponding representation.

Limits to the Usability of Iconic Memory

Directory of Open Access Journals (Sweden)

Ronald A. Rensink

2014-08-01

Full Text Available Human vision briefly retains a trace of a stimulus after it disappears. This trace—iconic memory—is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alternating between visible and iconic representations. However, the duration over which it can be used depends on the type of task: some tasks can use iconic memory for at least 240 ms, others for only about 190 ms, while others for no more than about 120 ms. The existence of these different limits suggests that iconic memory may have multiple layers, each corresponding to a particular level of the visual hierarchy. In this view, the inability to use a layer of iconic memory may reflect an inability to maintain feedback connections to the corresponding representation.

Global Communication with Icons in Environmental Contexts

OpenAIRE

Heimbürger, Anneli

2016-01-01

Icons are small signs with fixed meanings. Icons are usually context specific. For example in the context of a hotel, the client can often find icons in hotel room books and safety guides. Scandic Hotel chain, for example, currently provides the manual for its safety system in 14 languages. There are at least two major shortcomings of this system: (1) in emergency or panic situations, it is very difficult to find your own language from the leaflet, and (2) there are no Asian ...

Wireless sensor networks architectures and protocols

CERN Document Server

Callaway, Jr, Edgar H

2003-01-01

Introduction to Wireless Sensor NetworksApplications and MotivationNetwork Performance ObjectivesContributions of this BookOrganization of this BookThe Development of Wireless Sensor NetworksEarly Wireless NetworksWireless Data NetworksWireless Sensor and Related NetworksConclusionThe Physical LayerSome Physical Layer ExamplesA Practical Physical Layer for Wireless Sensor NetworksSimulations and ResultsConclusionThe Data Link LayerMedium Access Control TechniquesThe Mediation DeviceSystem Analysis and SimulationConclusionThe Network LayerSome Network Design ExamplesA Wireless Sensor Network De

Rapid iconic erasure without masking.

Science.gov (United States)

Tijus, Charles Albert; Reeves, Adam

2004-01-01

We report on the erasure of the iconic memory of an array of 12 black letters flashed on a continuously- present white field. Erasure is accomplished by replacing the 16 ms letter array (frame 1) with a blank white frame for 16 ms (frame 2). The letter array returns in frame 3, with from one to six letters missing. Report of the missing letters is accurate without the blank white frame but is impoverished with it, as if interposing the blank erases the icon. Erasure occurs without any obvious luminance masking, 'mud splashes', pattern masking (backward, forward, or metacontrast), lateral masking, or masking by object substitution. Erasure is greatly decreased if the blank is presented one frame earlier or later. We speculate that erasure is due to a rapid reset of the icon produced by an informational mis-match.

30-Gb/s bidirectional transparent optical transmission with an MMF access and an indoor optical wireless link

NARCIS (Netherlands)

Chen, H.; Boom, van den H.P.A.; Tangdiongga, E.; Koonen, A.M.J.

2012-01-01

This letter describes a 30-Gb/s bidirectional transparent optical transmission, over a 4.4-km multimode fiber (MMF) in combination with an indoor optical wireless (OW) link, which could provide limited mobility. Due to MMF's advantages, such as lower installation costs and easy maintenance, it is

20-meter underwater wireless optical communication link with 15 Gbps data rate

KAUST Repository

Shen, Chao

2016-10-24

The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (∼10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10-5, and 3.0 × 10-3, respectively, which pass well the forward error correction (FEC) criterion. © 2016 Optical Society of America.

20-meter underwater wireless optical communication link with 15 Gbps data rate

KAUST Repository

Shen, Chao; Guo, Yong; Oubei, Hassan M.; Ng, Tien Khee; Liu, Guangyu; Park, Kihong; Ho, Kang-Ting; Alouini, Mohamed-Slim; Ooi, Boon S.

2016-01-01

The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (∼10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10-5, and 3.0 × 10-3, respectively, which pass well the forward error correction (FEC) criterion. © 2016 Optical Society of America.

Mapping Language to the World: The Role of Iconicity in the Sign Language Input

Science.gov (United States)

Perniss, Pamela; Lu, Jenny C.; Morgan, Gary; Vigliocco, Gabriella

2018-01-01

Most research on the mechanisms underlying referential mapping has assumed that learning occurs in ostensive contexts, where label and referent co-occur, and that form and meaning are linked by arbitrary convention alone. In the present study, we focus on "iconicity" in language, that is, resemblance relationships between form and…

Investigation of interference in multiple-input multiple-output wireless transmission at W band for an optical wireless integration system.

Science.gov (United States)

Li, Xinying; Yu, Jianjun; Dong, Ze; Zhang, Junwen; Chi, Nan; Yu, Jianguo

2013-03-01

We experimentally investigate the interference in multiple-input multiple-output (MIMO) wireless transmission by adjusting the relative locations of horn antennas (HAs) in a 100 GHz optical wireless integration system, which can deliver a 50 Gb/s polarization-division-multiplexing quadrature-phase-shift-keying signal over 80 km single-mode fiber-28 and a 2×2 MIMO wireless link. For the parallel 2×2 MIMO wireless link, each receiver HA can only get wireless power from the corresponding transmitter HA, while for the crossover ones, the receiver HA can get wireless power from two transmitter HAs. At the wireless receiver, polarization demultiplexing is realized by the constant modulus algorithm (CMA) in the digital-signal-processing part. Compared to the parallel case, wireless interference causes about 2 dB optical signal-to-noise ratio penalty at a bit-error ratio (BER) of 3.8×10(-3) for the crossover cases if similar CMA taps are employed. The increase in CMA tap length can reduce wireless interference and improve BER performance. Furthermore, more CMA taps should be adopted to overcome the severe wireless interference when two pairs of transmitter and receiver HAs have different wireless distances.

Converged wireline and wireless signal transport over optical fibre access links

DEFF Research Database (Denmark)

Tafur Monroy, Idelfonso; Prince, Kamau; Osadchiy, Alexey Vladimirovich

2009-01-01

This article reviews emerging trends in converged optical-wireless communication systems and outline the role that photonic technologies are playing in making the vision of a wireline-wireless converged signal transport network a reality.......This article reviews emerging trends in converged optical-wireless communication systems and outline the role that photonic technologies are playing in making the vision of a wireline-wireless converged signal transport network a reality....

The Road to Language Learning Is Not Entirely Iconic: Iconicity, Neighborhood Density, and Frequency Facilitate Acquisition of Sign Language.

Science.gov (United States)

Caselli, Naomi K; Pyers, Jennie E

2017-07-01

Iconic mappings between words and their meanings are far more prevalent than once estimated and seem to support children's acquisition of new words, spoken or signed. We asked whether iconicity's prevalence in sign language overshadows two other factors known to support the acquisition of spoken vocabulary: neighborhood density (the number of lexical items phonologically similar to the target) and lexical frequency. Using mixed-effects logistic regressions, we reanalyzed 58 parental reports of native-signing deaf children's productive acquisition of 332 signs in American Sign Language (ASL; Anderson & Reilly, 2002) and found that iconicity, neighborhood density, and lexical frequency independently facilitated vocabulary acquisition. Despite differences in iconicity and phonological structure between signed and spoken language, signing children, like children learning a spoken language, track statistical information about lexical items and their phonological properties and leverage this information to expand their vocabulary.

What becomes an icon most?

Science.gov (United States)

Holt, Douglas B

2003-03-01

Some brands become icons. Think of Nike, Apple, Harley-Davidson: They're the brands every marketer regards with awe. But they are not built according to the principles of conventional marketing, says Harvard Business School marketing professor Douglas Holt. Iconic brands beat the competition not just by delivering innovative benefits, services, or technologies but by forging a deep connection with the culture. A brand becomes an icon when it offers a compelling myth, a story that can help people resolve tensions in their lives. The deepest source of tension in modern society is the disparity between national ideology and the average citizen's reality. When ideologies shift, myths become even more important, and in America, the most potent myths are depictions of rebels. Mountain Dew has long offered a rebel myth in ads showing exciting, vital men who are far from the ideological model of success. Loyal customers drink the beverage to consume the myth. But Mountain Dew's greatest achievement is that it has retained its iconic power by creating fresh rebel myths to suit the tensions of each era: first the hillbilly, who stood in stark contrast to the organization man of the 1950s and 1960s; then the redneck, who rebelled against the investment bankers and consultants of the 1970s and 1980s; and most recently the slacker, who rejects the values and behaviors that, for the past decade, have marked the successful executive. Holt says marketers can learn from Mountain Dew and other iconic brands if they are willing to move beyond conventional brand management and acquire knowledge and skills they may not have. They must learn to target national contradictions instead of just consumer segments, create myths that make sense of confusing societal changes, and speak with a rebel's voice.

Iconic memory and parietofrontal network: fMRI study using temporal integration.

Science.gov (United States)

Saneyoshi, Ayako; Niimi, Ryosuke; Suetsugu, Tomoko; Kaminaga, Tatsuro; Yokosawa, Kazuhiko

2011-08-03

We investigated the neural basis of iconic memory using functional magnetic resonance imaging. The parietofrontal network of selective attention is reportedly relevant to readout from iconic memory. We adopted a temporal integration task that requires iconic memory but not selective attention. The results showed that the task activated the parietofrontal network, confirming that the network is involved in readout from iconic memory. We further tested a condition in which temporal integration was performed by visual short-term memory but not by iconic memory. However, no brain region revealed higher activation for temporal integration by iconic memory than for temporal integration by visual short-term memory. This result suggested that there is no localized brain region specialized for iconic memory per se.

An iconic programming language for sensor-based robots

Science.gov (United States)

Gertz, Matthew; Stewart, David B.; Khosla, Pradeep K.

1993-01-01

In this paper we describe an iconic programming language called Onika for sensor-based robotic systems. Onika is both modular and reconfigurable and can be used with any system architecture and real-time operating system. Onika is also a multi-level programming environment wherein tasks are built by connecting a series of icons which, in turn, can be defined in terms of other icons at the lower levels. Expert users are also allowed to use control block form to define servo tasks. The icons in Onika are both shape and color coded, like the pieces of a jigsaw puzzle, thus providing a form of error control in the development of high level applications.

20-meter underwater wireless optical communication link with 1.5 Gbps data rate.

Science.gov (United States)

Shen, Chao; Guo, Yujian; Oubei, Hassan M; Ng, Tien Khee; Liu, Guangyu; Park, Ki-Hong; Ho, Kang-Ting; Alouini, Mohamed-Slim; Ooi, Boon S

2016-10-31

The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (~10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10-5, and 3.0 × 10-3, respectively, which pass well the forward error correction (FEC) criterion.

Limited capacity for contour curvature in iconic memory.

Science.gov (United States)

Sakai, Koji

2006-06-01

We measured the difference threshold for contour curvature in iconic memory by using the cued discrimination method. The study stimulus consisting of 2 to 6 curved contours was briefly presented in the fovea, followed by two lines as cues. Subjects discriminated the curvature of two cued curves. The cue delays were 0 msec. and 300 msec. in Exps. 1 and 2, respectively, and 50 msec. before the study offset in Exp. 3. Analysis of data from Exps. 1 and 2 showed that the Weber fraction rose monotonically with the increase in set size. Clear set-size effects indicate that iconic memory has a limited capacity. Moreover, clear set-size effect in Exp. 3 indicates that perception itself has a limited capacity. Larger set-size effects in Exp. 1 than in Exp. 3 suggest that iconic memory after perceptual process has limited capacity. These properties of iconic memory at threshold level are contradictory to the traditional view that iconic memory has a high capacity both at suprathreshold and categorical levels.

Simulative Analysis of Inter-Satellite Optical Wireless Communication (IsOWC) Link with EDFA

Science.gov (United States)

Singh, Mehtab; Singh, Navpreet

2018-04-01

In this paper, simulative analysis and performance comparison of different EDFA (Erbium-doped fiber amplifier) configurations in a 10 Gbps inter-satellite optical wireless communication (IsOWC) link have been reported for a 5,000 km long link and 1,550 nm operating wavelength. The results show that system in which both pre-amplifier and booster amplifier stages are implemented simultaneously outperforms systems with only pre-amplifier and booster amplifier stage. From the results, it can be seen that by deploying a transmission power level of 15 dBm, a link distance of 9,600 km can be achieved with a quality factor of 6.01 dB and BER (Bit error rate) of 1.07×10-9. Also, in this paper, the performance of an 8×7 Gbps WDM-IsOWC link has been reported. The results show that by using both EDFA pre-amplifier and booster amplifier stages, a link distance of 8,000 km for each channel is achievable with desired performance levels (Q≥6 and BER≤10-9). Also, the effect of channel spacing on the performance of WDM-IsOWC link is investigated. The results show that the received signal has acceptable performance levels when the channel spacing is 100 GHz but when the channel spacing is reduced to 80 GHz, the quality of the received signal degrades and link distance decreases.

A study of the impact of frequency selectivity on link adaptive wireless LAN systems

OpenAIRE

Armour, SMD; Doufexi, A; Nix, AR; Bull, DR

2002-01-01

Wireless local area networks (WLANs) supporting broadband multimedia communication are being developed and standardized around the world. The HIPERLAN/2, 802.11a and HiSWANa standards provide channel adaptive data rates between 6 and 54 Mbps in the 5GHz radio band. The link adaptation mechanism is not specified in the standards. In this paper the performance of the HIPERLAN/2 system is evaluated in terms of throughput in a range of test channels with different degrees of frequency selectivity...

A study on design guidelines for the icons used in nuclear power plants

International Nuclear Information System (INIS)

Lee, Jung Woon; Lee, Yong Hee; Oh, In Seok; Lee, Hyun Chul; Lee, Dhong Ha

2004-05-01

In this project, advantages and disadvantages of icons on electronic displays were analyzed, and design procedures, design evaluation principles, and design guidelines for icons on electronic displays were developed. In addition, as design guidelines for special effects applicable to icons on electronic displays, guidelines for color coding, flashing, and 3-dimensional effects were developed. A questionnaire survey was performed to investigate how NPP operators consider methods representing icons on electronic displays (such as colors, dynamic effects, and 3-dimensional effects) compared to methods representing icons by using outlines in the P and ID drawings. NPP operators' preference of the icons designed in accordance with icon design guidelines to the icons without considering the guidelines was also investigated

Promoting Wired Links in Wireless Mesh Networks: An Efficient Engineering Solution

Science.gov (United States)

Barekatain, Behrang; Raahemifar, Kaamran; Ariza Quintana, Alfonso; Triviño Cabrera, Alicia

2015-01-01

Wireless Mesh Networks (WMNs) cannot completely guarantee good performance of traffic sources such as video streaming. To improve the network performance, this study proposes an efficient engineering solution named Wireless-to-Ethernet-Mesh-Portal-Passageway (WEMPP) that allows effective use of wired communication in WMNs. WEMPP permits transmitting data through wired and stable paths even when the destination is in the same network as the source (Intra-traffic). Tested with four popular routing protocols (Optimized Link State Routing or OLSR as a proactive protocol, Dynamic MANET On-demand or DYMO as a reactive protocol, DYMO with spanning tree ability and HWMP), WEMPP considerably decreases the end-to-end delay, jitter, contentions and interferences on nodes, even when the network size or density varies. WEMPP is also cost-effective and increases the network throughput. Moreover, in contrast to solutions proposed by previous studies, WEMPP is easily implemented by modifying the firmware of the actual Ethernet hardware without altering the routing protocols and/or the functionality of the IP/MAC/Upper layers. In fact, there is no need for modifying the functionalities of other mesh components in order to work with WEMPPs. The results of this study show that WEMPP significantly increases the performance of all routing protocols, thus leading to better video quality on nodes. PMID:25793516

Security For Wireless Sensor Network

OpenAIRE

Saurabh Singh,; Dr. Harsh Kumar Verma

2011-01-01

Wireless sensor network is highly vulnerable to attacks because it consists of various resourceconstrained devices with their low battery power, less memory, and associated low energy. Sensor nodescommunicate among themselves via wireless links. However, there are still a lot of unresolved issues in wireless sensor networks of which security is one of the hottest research issues. Sensor networks aredeployed in hostile environments. Environmental conditions along with resource-constraints give...

Asymptotic Performance Analysis of the k-th Best Link Selection over Wireless Fading Channels: An Extreme Value Theory Approach

KAUST Repository

Al-Badarneh, Yazan Hussein

2018-01-25

We consider a general selection-diversity (SD) scheme in which the k-th best link is selected from a number of links. We use extreme value theory (EVT) to derive simple closed-form asymptotic expressions for the average throughput, effective throughput and average bit error probability (BEP) for the k-th best link over various channel models that are widely used to characterize fading in wireless communication systems. As an application example, we consider the Weibull fading channel model and verify the accuracy of the derived asymptotic expressions through Monte Carlo simulations.

Asymptotic Performance Analysis of the k-th Best Link Selection over Wireless Fading Channels: An Extreme Value Theory Approach

KAUST Repository

Al-Badarneh, Yazan Hussein; Georghiades, Costas; Alouini, Mohamed-Slim

2018-01-01

We consider a general selection-diversity (SD) scheme in which the k-th best link is selected from a number of links. We use extreme value theory (EVT) to derive simple closed-form asymptotic expressions for the average throughput, effective throughput and average bit error probability (BEP) for the k-th best link over various channel models that are widely used to characterize fading in wireless communication systems. As an application example, we consider the Weibull fading channel model and verify the accuracy of the derived asymptotic expressions through Monte Carlo simulations.

Visual Iconicity Across Sign Languages: Large-Scale Automated Video Analysis of Iconic Articulators and Locations

Science.gov (United States)

Östling, Robert; Börstell, Carl; Courtaux, Servane

2018-01-01

We use automatic processing of 120,000 sign videos in 31 different sign languages to show a cross-linguistic pattern for two types of iconic form–meaning relationships in the visual modality. First, we demonstrate that the degree of inherent plurality of concepts, based on individual ratings by non-signers, strongly correlates with the number of hands used in the sign forms encoding the same concepts across sign languages. Second, we show that certain concepts are iconically articulated around specific parts of the body, as predicted by the associational intuitions by non-signers. The implications of our results are both theoretical and methodological. With regard to theoretical implications, we corroborate previous research by demonstrating and quantifying, using a much larger material than previously available, the iconic nature of languages in the visual modality. As for the methodological implications, we show how automatic methods are, in fact, useful for performing large-scale analysis of sign language data, to a high level of accuracy, as indicated by our manual error analysis.

Connectivity model for Inter-working multi-hop wireless networks

CSIR Research Space (South Africa)

Salami, O

2009-08-01

Full Text Available pairs in inter-working multi-hop wireless networks can be evaluated based on the availability of radio links and communication routes. This paper presents an analytical study of the link and route availability in inter-working multi-hop wireless networks....

Wireless sensor communications and internet connectivity for sensor networks

Energy Technology Data Exchange (ETDEWEB)

Dunbar, M. [Crossbow Technology, Inc., San Jose, CA (United States)

2001-07-01

A wireless sensor network architecture is an integrated hardware/software solution that has the potential to change the way sensors are used in a virtually unlimited range of industries and applications. By leveraging Bluetooth wireless technology for low-cost, short-range radio links, wireless sensor networks such as CrossNet{sup TM} enable users to create wireless sensor networks. These wireless networks can link dozens or hundreds of sensors of disparate types and brands with data acquisition/analysis systems, such as handheld devices, internet-enabled laptop or desktop PCs. The overwhelming majority of sensor applications are hard-wired at present, and since wiring is often the most time-consuming, tedious, trouble-prone and expensive aspect of sensor applications, users in many fields will find compelling reasons to adopt the wireless sensor network solution. (orig.)

Effects of wireless packet loss in industrial process control systems.

Science.gov (United States)

Liu, Yongkang; Candell, Richard; Moayeri, Nader

2017-05-01

Timely and reliable sensing and actuation control are essential in networked control. This depends on not only the precision/quality of the sensors and actuators used but also on how well the communications links between the field instruments and the controller have been designed. Wireless networking offers simple deployment, reconfigurability, scalability, and reduced operational expenditure, and is easier to upgrade than wired solutions. However, the adoption of wireless networking has been slow in industrial process control due to the stochastic and less than 100% reliable nature of wireless communications and lack of a model to evaluate the effects of such communications imperfections on the overall control performance. In this paper, we study how control performance is affected by wireless link quality, which in turn is adversely affected by severe propagation loss in harsh industrial environments, co-channel interference, and unintended interference from other devices. We select the Tennessee Eastman Challenge Model (TE) for our study. A decentralized process control system, first proposed by N. Ricker, is adopted that employs 41 sensors and 12 actuators to manage the production process in the TE plant. We consider the scenario where wireless links are used to periodically transmit essential sensor measurement data, such as pressure, temperature and chemical composition to the controller as well as control commands to manipulate the actuators according to predetermined setpoints. We consider two models for packet loss in the wireless links, namely, an independent and identically distributed (IID) packet loss model and the two-state Gilbert-Elliot (GE) channel model. While the former is a random loss model, the latter can model bursty losses. With each channel model, the performance of the simulated decentralized controller using wireless links is compared with the one using wired links providing instant and 100% reliable communications. The sensitivity of the

Iconic memory for the gist of natural scenes.

Science.gov (United States)

Clarke, Jason; Mack, Arien

2014-11-01

Does iconic memory contain the gist of multiple scenes? Three experiments were conducted. In the first, four scenes from different basic-level categories were briefly presented in one of two conditions: a cue or a no-cue condition. The cue condition was designed to provide an index of the contents of iconic memory of the display. Subjects were more sensitive to scene gist in the cue condition than in the no-cue condition. In the second, the scenes came from the same basic-level category. We found no difference in sensitivity between the two conditions. In the third, six scenes from different basic level categories were presented in the visual periphery. Subjects were more sensitive to scene gist in the cue condition. These results suggest that scene gist is contained in iconic memory even in the visual periphery; however, iconic representations are not sufficiently detailed to distinguish between scenes coming from the same category. Copyright © 2014 Elsevier Inc. All rights reserved.

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

Directory of Open Access Journals (Sweden)

Ben Minnaert

2017-01-01

Full Text Available Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this optimal network as a function of the characteristics of the capacitive wireless link, as well for the series as for the parallel topology. The results are compared with the inductive power transfer system. Introduction of a new concept, the coupling function, enables the description of the compensation network of both an inductive and a capacitive system in two elegant equations, valid for the series and the parallel topology. This approach allows better understanding of the fundamentals of the wireless power transfer link, necessary for the design of an efficient system.

Choosing colors for map display icons using models of visual search.

Science.gov (United States)

Shive, Joshua; Francis, Gregory

2013-04-01

We show how to choose colors for icons on maps to minimize search time using predictions of a model of visual search. The model analyzes digital images of a search target (an icon on a map) and a search display (the map containing the icon) and predicts search time as a function of target-distractor color distinctiveness and target eccentricity. We parameterized the model using data from a visual search task and performed a series of optimization tasks to test the model's ability to choose colors for icons to minimize search time across icons. Map display designs made by this procedure were tested experimentally. In a follow-up experiment, we examined the model's flexibility to assign colors in novel search situations. The model fits human performance, performs well on the optimization tasks, and can choose colors for icons on maps with novel stimuli to minimize search time without requiring additional model parameter fitting. Models of visual search can suggest color choices that produce search time reductions for display icons. Designers should consider constructing visual search models as a low-cost method of evaluating color assignments.

Iconic memory is not a case of attention-free awareness.

Science.gov (United States)

Mack, Arien; Erol, Muge; Clarke, Jason

2015-05-01

Whether or not awareness entails attention is a much debated question. Since iconic memory has been generally assumed to be attention-free, it has been considered an important piece of evidence that it does not (Koch & Tsuchiya, 2007). Therefore the question of the role of attention in iconic memory matters. Recent evidence (Persuh, Genzer, & Melara, 2012), suggests that iconic memory does depend on attention. Because of the centrality of iconic memory to this debate, we looked again at the role of attention in iconic memory using a standard whole versus partial report task of letters in a 3×2 matrix. We manipulated attention to the array by coupling it with a second task that was either easy or hard and by manipulating the probability of which task was to be performed on any given trial. When attention was maximally diverted from the matrix, participants were able to report less than a single item, confirming the prior results and supporting the conclusion that iconic memory entails attention. It is not an instance of attention-free awareness. Copyright © 2015 Elsevier Inc. All rights reserved.

Partial report and other sampling procedures overestimate the duration of iconic memory.

Science.gov (United States)

Appelman, I B

1980-03-01

In three experiments, subjects estimated the duration of a brief visual image (iconic memory) either directly by adjusting onset of a click to offset of the visual image, or indirectly with a Sperling partial report (sampling) procedure. The results indicated that partial report and other sampling procedures may reflect other brief phenomena along with iconic memory. First, the partial report procedure yields a greater estimate of the duration of iconic memory than the more direct click method. Second, the partial report estimate of the duration of iconic memory is affected if the subject is required to simultaneously retain a list of distractor items (memory load), while the click method estimate of the duration of iconic memory is not affected by a memory load. Finally, another sampling procedure based on visual cuing yields different estimates of the duration of iconic memory depending on how many items are cued. It was concluded that partial report and other sampling procedures overestimate the duration of iconic memory.

Design and Optimization of a 3-Coil Inductive Link for Efficient Wireless Power Transmission.

Science.gov (United States)

Kiani, Mehdi; Jow, Uei-Ming; Ghovanloo, Maysam

2011-07-14

Inductive power transmission is widely used to energize implantable microelectronic devices (IMDs), recharge batteries, and energy harvesters. Power transfer efficiency (PTE) and power delivered to the load (PDL) are two key parameters in wireless links, which affect the energy source specifications, heat dissipation, power transmission range, and interference with other devices. To improve the PTE, a 4-coil inductive link has been recently proposed. Through a comprehensive circuit based analysis that can guide a design and optimization scheme, we have shown that despite achieving high PTE at larger coil separations, the 4-coil inductive links fail to achieve a high PDL. Instead, we have proposed a 3-coil inductive power transfer link with comparable PTE over its 4-coil counterpart at large coupling distances, which can also achieve high PDL. We have also devised an iterative design methodology that provides the optimal coil geometries in a 3-coil inductive power transfer link. Design examples of 2-, 3-, and 4-coil inductive links have been presented, and optimized for 13.56 MHz carrier frequency and 12 cm coupling distance, showing PTEs of 15%, 37%, and 35%, respectively. At this distance, the PDL of the proposed 3-coil inductive link is 1.5 and 59 times higher than its equivalent 2- and 4-coil links, respectively. For short coupling distances, however, 2-coil links remain the optimal choice when a high PDL is required, while 4-coil links are preferred when the driver has large output resistance or small power is needed. These results have been verified through simulations and measurements.

Impact of Radio Link Unreliability on the Connectivity of Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Gorce Jean-Marie

2007-01-01

Full Text Available Many works have been devoted to connectivity of ad hoc networks. This is an important feature for wireless sensor networks (WSNs to provide the nodes with the capability of communicating with one or several sinks. In most of these works, radio links are assumed ideal, that is, with no transmission errors. To fulfil this assumption, the reception threshold should be high enough to guarantee that radio links have a low transmission error probability. As a consequence, all unreliable links are dismissed. This approach is suboptimal concerning energy consumption because unreliable links should permit to reduce either the transmission power or the number of active nodes. The aim of this paper is to quantify the contribution of unreliable long hops to an increase of the connectivity of WSNs. In our model, each node is assumed to be connected to each other node in a probabilistic manner. Such a network is modeled as a complete random graph, that is, all edges exist. The instantaneous node degree is then defined as the number of simultaneous valid single-hop receptions of the same message, and finally the mean node degree is computed analytically in both AWGN and block-fading channels. We show the impact on connectivity of two MACs and routing parameters. The first one is the energy detection level such as the one used in carrier sense mechanisms. The second one is the reliability threshold used by the routing layer to select stable links only. Both analytic and simulation results show that using opportunistic protocols is challenging.

Impact of Radio Link Unreliability on the Connectivity of Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Jean-Marie Gorce

2007-06-01

Full Text Available Many works have been devoted to connectivity of ad hoc networks. This is an important feature for wireless sensor networks (WSNs to provide the nodes with the capability of communicating with one or several sinks. In most of these works, radio links are assumed ideal, that is, with no transmission errors. To fulfil this assumption, the reception threshold should be high enough to guarantee that radio links have a low transmission error probability. As a consequence, all unreliable links are dismissed. This approach is suboptimal concerning energy consumption because unreliable links should permit to reduce either the transmission power or the number of active nodes. The aim of this paper is to quantify the contribution of unreliable long hops to an increase of the connectivity of WSNs. In our model, each node is assumed to be connected to each other node in a probabilistic manner. Such a network is modeled as a complete random graph, that is, all edges exist. The instantaneous node degree is then defined as the number of simultaneous valid single-hop receptions of the same message, and finally the mean node degree is computed analytically in both AWGN and block-fading channels. We show the impact on connectivity of two MACs and routing parameters. The first one is the energy detection level such as the one used in carrier sense mechanisms. The second one is the reliability threshold used by the routing layer to select stable links only. Both analytic and simulation results show that using opportunistic protocols is challenging.

Data transmission techniques for short-range optical fiber and wireless communication links

DEFF Research Database (Denmark)

Pham, Tien Thang

The research work described in this thesis is devoted to experimental investigation of techniques for cost-effective high-speed optical communications supporting both wired and wireless services. The main contributions of this thesis have expanded the state-of-the-art in two main areas: high......-speed optical/wireless integration and advanced modulation formats for intensity modulation with direct detection (IM/DD) optical systems. Regarding optical/wireless integration, this thesis focuses on integration of broadband ultra-wide band (UWB) and 60-GHz band wireless systems into optical fiber access...... networks to distribute wireless services in personal area networks (PANs). Photonic technologies to generate and distribute gigabit UWB and 60-GHz-band signals are proposed and demonstrated. Two novel methods are proposed and demonstrated to optically generate Federal Communications Commission (FCC...

Assistance System for Disabled People: A Robot Controlled by Blinking and Wireless Link

Science.gov (United States)

Del Val, Lara; Jiménez, María I.; Alonso, Alonso; de La Rosa, Ramón; Izquierdo, Alberto; Carrera, Albano

Disabled people already profit from a lot of technical assistance that improves their quality of life. This article presents a system which will allow interaction between a physically disabled person and his environment. This system is controlled by voluntary muscular movements, particularly those of face muscles. These movements will be translated into machine-understandable instructions, and they will be sent by means of a wireless link to a mobile robot that will execute them. Robot includes a video camera, in order to show the user the environment of the route that the robot follows. This system gives a greater personal autonomy to people with reduced mobility.

Iconic Gestures as Undervalued Representations during Science Teaching

Science.gov (United States)

Chue, Shien; Lee, Yew-Jin; Tan, Kim Chwee Daniel

2015-01-01

Iconic gestures that are ubiquitous in speech are integral to human meaning-making. However, few studies have attempted to map out the role of these gestures in science teaching. This paper provides a review of existing literature in everyday communication and education to articulate potential contributions of iconic gestures for science teaching.…

Proposal of Wireless Traffic Control Schemes for Wireless LANs

Science.gov (United States)

Hiraguri, Takefumi; Ichikawa, Takeo; Iizuka, Masataka; Kubota, Shuji

This paper proposes two traffic control schemes to support the communication quality of multimedia streaming services such as VoIP and audio/video over IEEE 802.11 wireless LAN systems. The main features of the proposed scheme are bandwidth control for each flow of the multimedia streaming service and load balancing between access points (APs) of the wireless LAN by using information of data link, network and transport layers. The proposed schemes are implemented on a Linux machine which is called the wireless traffic controller (WTC). The WTC connects a high capacity backbone network and an access network to which the APs are attached. We evaluated the performance of the proposed WTC and confirmed that the communication quality of the multimedia streaming would be greatly improved by using this technique.

Effects of Iconicity and Semantic Relatedness on Lexical Access in American Sign Language

Science.gov (United States)

Bosworth, Rain G.; Emmorey, Karen

2010-01-01

Iconicity is a property that pervades the lexicon of many sign languages, including American Sign Language (ASL). Iconic signs exhibit a motivated, nonarbitrary mapping between the form of the sign and its meaning. We investigated whether iconicity enhances semantic priming effects for ASL and whether iconic signs are recognized more quickly than…

Icon arrays help younger children's proportional reasoning.

Science.gov (United States)

Ruggeri, Azzurra; Vagharchakian, Laurianne; Xu, Fei

2018-06-01

We investigated the effects of two context variables, presentation format (icon arrays or numerical frequencies) and time limitation (limited or unlimited time), on the proportional reasoning abilities of children aged 7 and 10 years, as well as adults. Participants had to select, between two sets of tokens, the one that offered the highest likelihood of drawing a gold token, that is, the set of elements with the greater proportion of gold tokens. Results show that participants performed better in the unlimited time condition. Moreover, besides a general developmental improvement in accuracy, our results show that younger children performed better when proportions were presented as icon arrays, whereas older children and adults were similarly accurate in the two presentation format conditions. Statement of contribution What is already known on this subject? There is a developmental improvement in proportional reasoning accuracy. Icon arrays facilitate reasoning in adults with low numeracy. What does this study add? Participants were more accurate when they were given more time to make the proportional judgement. Younger children's proportional reasoning was more accurate when they were presented with icon arrays. Proportional reasoning abilities correlate with working memory, approximate number system, and subitizing skills. © 2018 The British Psychological Society.

Seeing Iconic Gestures While Encoding Events Facilitates Children's Memory of These Events.

Science.gov (United States)

Aussems, Suzanne; Kita, Sotaro

2017-11-08

An experiment with 72 three-year-olds investigated whether encoding events while seeing iconic gestures boosts children's memory representation of these events. The events, shown in videos of actors moving in an unusual manner, were presented with either iconic gestures depicting how the actors performed these actions, interactive gestures, or no gesture. In a recognition memory task, children in the iconic gesture condition remembered actors and actions better than children in the control conditions. Iconic gestures were categorized based on how much of the actors was represented by the hands (feet, legs, or body). Only iconic hand-as-body gestures boosted actor memory. Thus, seeing iconic gestures while encoding events facilitates children's memory of those aspects of events that are schematically highlighted by gesture. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

Beyond 100 Gbit/s wireless connectivity enabled by THz photonics

DEFF Research Database (Denmark)

Yu, Xianbin; Jia, Shi; Pang, Xiaodan

2017-01-01

Beyond 100Gbit/s wireless connectivity is appreciated in many scenarios, such as big data wireless cloud, ultrafast wireless download, large volume data transfer, etc. In this paper, we will present our recent achievements on beyond 100Gbit/s ultrafast terahertz (THz) wireless links enabled by TH...... photonics....

Experimental Characterization of LTE Wireless Links in High-Speed Trains

Directory of Open Access Journals (Sweden)

Tomás Domínguez-Bolaño

2017-01-01

Full Text Available Multimedia and data-based services experienced a nonstopping growth over the last few years. People are continuously on the move using devices to access multimedia contents or other data-based services. Due to this, railway companies are showing a great interest in deploying broadband mobile wireless networks in high-speed-trains with the aim of supporting both passenger services provisioning as well as automatic train control and signaling. Nowadays, the most widely used technology for communications between trains and the railway infrastructure is GSM for Railways (GSM-R; however, it has limited capabilities to support such advanced services. Due to its success in the mass market, Long Term Evolution (LTE seems to be the best candidate to substitute GSM-R. In this paper, we experimentally characterize the downlink between an LTE Evolved NodeB (eNodeB and a high-speed train in a commercial high-speed line. We consider two links: the one between the eNodeB and the antennas placed outdoors on the train roof, and the direct link between the eNodeB and a receiver inside the train. Such a characterization consists in assessing the path loss, the Signal to Noise Ratio, the K-Factor, the Power Delay Profile, the delay spread, and the Doppler Power Spectral Density.

Young Children Create Iconic Gestures to Inform Others

Science.gov (United States)

Behne, Tanya; Carpenter, Malinda; Tomasello, Michael

2014-01-01

Much is known about young children's use of deictic gestures such as pointing. Much less is known about their use of other types of communicative gestures, especially iconic or symbolic gestures. In particular, it is unknown whether children can create iconic gestures on the spot to inform others. Study 1 provided 27-month-olds with the…

Partial Interference and Its Performance Impact on Wireless Multiple Access Networks

Directory of Open Access Journals (Sweden)

Lau WingCheong

2010-01-01

Full Text Available To determine the capacity of wireless multiple access networks, the interference among the wireless links must be accurately modeled. In this paper, we formalize the notion of the partial interference phenomenon observed in many recent wireless measurement studies and establish analytical models with tractable solutions for various types of wireless multiple access networks. In particular, we characterize the stability region of IEEE 802.11 networks under partial interference with two potentially unsaturated links numerically. We also provide a closed-form solution for the stability region of slotted ALOHA networks under partial interference with two potentially unsaturated links and obtain a partial characterization of the boundary of the stability region for the general M-link case. Finally, we derive a closed-form approximated solution for the stability region for general M-link slotted ALOHA system under partial interference effects. Based on our results, we demonstrate that it is important to model the partial interference effects while analyzing wireless multiple access networks. This is because such considerations can result in not only significant quantitative differences in the predicted system capacity but also fundamental qualitative changes in the shape of the stability region of the systems.

Challenging Aspects of Terahertz Terabit Wireless Communications

DEFF Research Database (Denmark)

Yu, Xianbin; Galili, Michael; Jepsen, Peter Uhd

The increasing demand on fast wireless communications, e.g. huge data file transferring and mobile broadband access, has driven wireless communication systems into a path towards Terabit era. Terahertz (THz) technology is promising due to its unique features, such as unlimited bandwidth available......, in terms of THz generation and link power budget. The THz atmospheric absorption is another critical issue to limit wireless communication range....

Microwave materials for wireless applications

CERN Document Server

Cruickshank, David B

2011-01-01

This practical resource offers you an in-depth, up-to-date understanding of the use of microwave magnetic materials for cutting-edge wireless applications. The book discusses device applications used in wireless infrastructure base stations, point-to-point radio links, and a range of more specialized microwave systems. You find detailed discussions on the attributes of each family of magnetic materials with respect to specific wireless applications. Moreover, the book addresses two of the hottest topics in the field today - insertion loss and intermodulation. This comprehensive reference also

Semantic distance as a critical factor in icon design for in-car infotainment systems.

Science.gov (United States)

Silvennoinen, Johanna M; Kujala, Tuomo; Jokinen, Jussi P P

2017-11-01

In-car infotainment systems require icons that enable fluent cognitive information processing and safe interaction while driving. An important issue is how to find an optimised set of icons for different functions in terms of semantic distance. In an optimised icon set, every icon needs to be semantically as close as possible to the function it visually represents and semantically as far as possible from the other functions represented concurrently. In three experiments (N = 21 each), semantic distances of 19 icons to four menu functions were studied with preference rankings, verbal protocols, and the primed product comparisons method. The results show that the primed product comparisons method can be efficiently utilised for finding an optimised set of icons for time-critical applications out of a larger set of icons. The findings indicate the benefits of the novel methodological perspective into the icon design for safety-critical contexts in general. Copyright © 2017 Elsevier Ltd. All rights reserved.

Global Communication with Icons : Hotel Safety as an Environmental Context

OpenAIRE

Heimbürger, Anneli; Khanom, Sukanya

2015-01-01

Icons are small signs with fixed meanings. Icons are usually context specific. For example in the context of a hotel, the client can often find icons in hotel room books and safety guides. Scandic Hotel chain, for example, currently provides the manual for its safety system in 14 languages. There are at least two major shortcomings of this system: (1) in emergency or panic situations, it is very difficult to find your own language from the leaflet, and (2) there are no Asian ...

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Comparison of European ICU patients in 2012 (ICON) versus 2002 (SOAP)

DEFF Research Database (Denmark)

Vincent, Jean-Louis; Lefrant, Jean-Yves; Kotfis, Katarzyna

2018-01-01

Occurrence in Acutely ill Patients (SOAP) study, an observational study conducted in European intensive care units in 2002, and the Intensive Care Over Nations (ICON) audit, a survey of intensive care unit patients conducted in 2012. RESULTS: We compared the 3147 patients from the SOAP study with the 4852...... patients from the ICON audit admitted to intensive care units in the same countries as those in the SOAP study. The ICON patients were older (62.5 ± 17.0 vs. 60.6 ± 17.4 years) and had higher severity scores than the SOAP patients. The proportion of patients with sepsis at any time during the intensive...... care unit stay was slightly higher in the ICON study (31.9 vs. 29.6%, p = 0.03). In multilevel analysis, the adjusted odds of ICU mortality were significantly lower for ICON patients than for SOAP patients, particularly in patients with sepsis [OR 0.45 (0.35-0.59), p

Towards iconic language for patient records, drug monographs, guidelines and medical search engines.

Science.gov (United States)

Lamy, Jean-Baptiste; Duclos, Catherine; Hamek, Saliha; Beuscart-Zéphir, Marie-Catherine; Kerdelhué, Gaetan; Darmoni, Stefan; Favre, Madeleine; Falcoff, Hector; Simon, Christian; Pereira, Suzanne; Serrot, Elisabeth; Mitouard, Thierry; Hardouin, Etienne; Kergosien, Yannick; Venot, Alain

2010-01-01

Practicing physicians have limited time for consulting medical knowledge and records. We have previously shown that using icons instead of text to present drug monographs may allow contraindications and adverse effects to be identified more rapidly and more accurately. These findings were based on the use of an iconic language designed for drug knowledge, providing icons for many medical concepts, including diseases, antecedents, drug classes and tests. In this paper, we describe a new project aimed at extending this iconic language, and exploring the possible applications of these icons in medicine. Based on evaluators' comments, focus groups of physicians and opinions of academic, industrial and associative partners, we propose iconic applications related to patient records, for example summarizing patient conditions, searching for specific clinical documents and helping to code structured data. Other applications involve the presentation of clinical practice guidelines and improving the interface of medical search engines. These new applications could use the same iconic language that was designed for drug knowledge, with a few additional items that respect the logic of the language.

Wireless telecommunication systems

CERN Document Server

Terré, Michel; Vivier, Emmanuelle

2013-01-01

Wireless telecommunication systems generate a huge amount of interest. In the last two decades, these systems have experienced at least three major technological leaps, and it has become impossible to imagine how society was organized without them. In this book, we propose a macroscopic approach on wireless systems, and aim at answering key questions about power, data rates, multiple access, cellular engineering and access networks architectures.We present a series of solved problems, whose objective is to establish the main elements of a global link budget in several radiocommunicati

Optical wireless connected objects for healthcare.

Science.gov (United States)

Toumieux, Pascal; Chevalier, Ludovic; Sahuguède, Stéphanie; Julien-Vergonjanne, Anne

2015-10-01

In this Letter the authors explore the communication capabilities of optical wireless technology for a wearable device dedicated to healthcare application. In an indoor environment sensible to electromagnetic perturbations such as a hospital, the use of optical wireless links can permit reducing the amount of radio frequencies in the patient environment. Moreover, this technology presents the advantage to be secure, low-cost and easy to deploy. On the basis of commercially available components, a custom-made wearable device is presented, which allows optical wireless transmission of accelerometer data in the context of physical activity supervision of post-stroke patients in hospital. Considering patient mobility, the experimental performance is established in terms of packet loss as a function of the number of receivers fixed to the ceiling. The results permit to conclude that optical wireless links can be used to perform such mobile remote monitoring applications. Moreover, based on the measurements obtained with one receiver, it is possible to theoretically determine the performance according to the number of receivers to be deployed.

Combined Rate and Power Allocation with Link Scheduling in Wireless Data Packet Relay Networks with Fading Channels

OpenAIRE

Subhrakanti Dey; Minyi Huang

2007-01-01

We consider a joint rate and power control problem in a wireless data traffic relay network with fading channels. The optimization problem is formulated in terms of power and rate selection, and link transmission scheduling. The objective is to seek high aggregate utility of the relay node when taking into account buffer load management and power constraints. The optimal solution for a single transmitting source is computed by a two-layer dynamic programming algorithm which leads to optimal ...

Small Worlds in the Tree Topologies of Wireless Sensor Networks

DEFF Research Database (Denmark)

Qiao, Li; Lingguo, Cui; Baihai, Zhang

2010-01-01

In this study, the characteristics of small worlds are investigated in the context of the tree topologies of wireless sensor networks. Tree topologies, which construct spatial graphs with larger characteristic path lengths than random graphs and small clustering coefficients, are ubiquitous...... in wireless sensor networks. Suffering from the link rewiring or the link addition, the characteristic path length of the tree topology reduces rapidly and the clustering coefficient increases greatly. The variety of characteristic path length influences the time synchronization characteristics of wireless...... sensor networks greatly. With the increase of the link rewiring or the link addition probability, the time synchronization error decreases drastically. Two novel protocols named LEACH-SW and TREEPSI-SW are proposed to improve the performances of the sensor networks, in which the small world...

Spectroscopic study of an icon painted on wooden panel

Directory of Open Access Journals (Sweden)

Stojanović Sofija R.

2015-01-01

Full Text Available Russian icon painted on wooden panel analyzed in this work is interesting for art historians because there is no precise information in which workshops it was made or who the author was. Similar icons are often found in churches and monasteries in our region. In order to obtain information about materials used for creation of investigated icon two micro-analytical techniques were used: Energy-Dispersive X-Ray Fluorescence spectroscopy (EDXRF and micro-Raman spectroscopy. Obtained results confirmed presence of following materials: lead-white, vermilion, minium, ultramarine, brown and green earth pigments and silver in combination with yellow organic varnish, which served to an iconographer for gilding. Ground layer was made of calcite. Blue pigment ultramarine was probably used for blue colour as well as for obtaining particulars hues in several parts of the paint layer. This can be important information for further research concerning particular workshop in which the icon was made. Identified materials are typical for Russian iconography of the 19th century. [Projekat Ministarstva nauke Republike Srbije, br. OI 177021 i OI 177012

Adaptive Wavelet Coding Applied in a Wireless Control System.

Science.gov (United States)

Gama, Felipe O S; Silveira, Luiz F Q; Salazar, Andrés O

2017-12-13

Wireless control systems can sense, control and act on the information exchanged between the wireless sensor nodes in a control loop. However, the exchanged information becomes susceptible to the degenerative effects produced by the multipath propagation. In order to minimize the destructive effects characteristic of wireless channels, several techniques have been investigated recently. Among them, wavelet coding is a good alternative for wireless communications for its robustness to the effects of multipath and its low computational complexity. This work proposes an adaptive wavelet coding whose parameters of code rate and signal constellation can vary according to the fading level and evaluates the use of this transmission system in a control loop implemented by wireless sensor nodes. The performance of the adaptive system was evaluated in terms of bit error rate (BER) versus E b / N 0 and spectral efficiency, considering a time-varying channel with flat Rayleigh fading, and in terms of processing overhead on a control system with wireless communication. The results obtained through computational simulations and experimental tests show performance gains obtained by insertion of the adaptive wavelet coding in a control loop with nodes interconnected by wireless link. These results enable the use of this technique in a wireless link control loop.

Adaptive Wavelet Coding Applied in a Wireless Control System

Directory of Open Access Journals (Sweden)

Felipe O. S. Gama

2017-12-01

Full Text Available Wireless control systems can sense, control and act on the information exchanged between the wireless sensor nodes in a control loop. However, the exchanged information becomes susceptible to the degenerative effects produced by the multipath propagation. In order to minimize the destructive effects characteristic of wireless channels, several techniques have been investigated recently. Among them, wavelet coding is a good alternative for wireless communications for its robustness to the effects of multipath and its low computational complexity. This work proposes an adaptive wavelet coding whose parameters of code rate and signal constellation can vary according to the fading level and evaluates the use of this transmission system in a control loop implemented by wireless sensor nodes. The performance of the adaptive system was evaluated in terms of bit error rate (BER versus E b / N 0 and spectral efficiency, considering a time-varying channel with flat Rayleigh fading, and in terms of processing overhead on a control system with wireless communication. The results obtained through computational simulations and experimental tests show performance gains obtained by insertion of the adaptive wavelet coding in a control loop with nodes interconnected by wireless link. These results enable the use of this technique in a wireless link control loop.

Scintillation index and performance analysis of wireless optical links over non-Kolmogorov weak turbulence based on generalized atmospheric spectral model.

Science.gov (United States)

Cang, Ji; Liu, Xu

2011-09-26

Based on the generalized spectral model for non-Kolmogorov atmospheric turbulence, analytic expressions of the scintillation index (SI) are derived for plane, spherical optical waves and a partially coherent Gaussian beam propagating through non-Kolmogorov turbulence horizontally in the weak fluctuation regime. The new expressions relate the SI to the finite turbulence inner and outer scales, spatial coherence of the source and spectral power-law and then used to analyze the effects of atmospheric condition and link length on the performance of wireless optical communication links. © 2011 Optical Society of America

Performance Evaluation of Underwater Wireless Optical Communications Links in the Presence of Different Air Bubble Populations

KAUST Repository

Oubei, Hassan M.; Elafandy, Rami T.; Park, Kihong; Ng, Tien Khee; Alouini, Mohamed-Slim; Ooi, Boon S.

2017-01-01

We experimentally evaluate the performance of underwater wireless optical communication (UWOC) links in the presence of different air bubbles. Air bubbles of different sizes and densities are generated by using an air pipe in conjunction with a submersible water pump of variable flow rate that help break up large bubbles into smaller bubbles. Received signal intensity measurements show that bubbles significantly degrade the performance of UWOC links. Large bubbles completely obstruct the optical beam and cause a deep fade. However, as the bubble size decreases, the level of deep fade also decreases because the optical beam is less susceptible to complete obstruction and more light reaches the detector. We also show that beam expansion could help mitigate the performance degradation due to the deep fade caused by air bubbles scatters in the channel.

Performance Evaluation of Underwater Wireless Optical Communications Links in the Presence of Different Air Bubble Populations

KAUST Repository

Oubei, Hassan M.

2017-03-16

We experimentally evaluate the performance of underwater wireless optical communication (UWOC) links in the presence of different air bubbles. Air bubbles of different sizes and densities are generated by using an air pipe in conjunction with a submersible water pump of variable flow rate that help break up large bubbles into smaller bubbles. Received signal intensity measurements show that bubbles significantly degrade the performance of UWOC links. Large bubbles completely obstruct the optical beam and cause a deep fade. However, as the bubble size decreases, the level of deep fade also decreases because the optical beam is less susceptible to complete obstruction and more light reaches the detector. We also show that beam expansion could help mitigate the performance degradation due to the deep fade caused by air bubbles scatters in the channel.

Domestic dogs comprehend human communication with iconic signs.

Science.gov (United States)

Kaminski, Juliane; Tempelmann, Sebastian; Call, Josep; Tomasello, Michael

2009-11-01

A key skill in early human development is the ability to comprehend communicative intentions as expressed in both nonlinguistic gestures and language. In the current studies, we confronted domestic dogs (some of whom knew many human 'words') with a task in which they had to infer the intended referent of a human's communicative act via iconic signs--specifically, replicas and photographs. Both trained and untrained dogs successfully used iconic replicas to fetch the desired item, with many doing so from the first trial. Dogs' ability to use photographs in this same situation was less consistent. Because simple matching to sample in experimental contexts typically takes hundreds of trials (and because similarity between iconic sign and target item did not predict success), we propose that dogs' skillful performance in the current task reflects important aspects of the comprehension of human communicative intentions.

What's in a name? The role of graphics, functions, and their interrelationships in icon identification.

Science.gov (United States)

McDougall, Siné; Isherwood, Sarah

2009-05-01

Communication using icons is now commonplace. It is therefore important to understand the processes involved in icon comprehension and the stimulus cues that individuals utilize to facilitate identification. In this study, we examined predictors of icon identification as participants gained experience with icons over a series of learning trials. A dynamic pattern of findings emerged in which the primary predictors of identification changed as learning progressed. In early learning trials, semantic distance (the closeness of the relationship between icon and function) was the best predictor of performance, accounting for up to 55% of the variance observed, whereas familiarity with the function was more important in later trials. Other stimulus characteristics, such as our familiarity with the graphic in the icon and its concreteness, were also found to be important for icon design. The theoretical implications of these findings are discussed, with particular emphasis on the parallels with picture naming. The icon identification norms from this study may be downloaded from brm.psychonomic-journals.org/content/supplemental.

Business Model Innovation: How Iconic Business Models Emerge

OpenAIRE

Mikhalkina, T.; Cabantous, L.

2015-01-01

Despite ample research on the topic of business model innovation, little is known about the cognitive processes whereby some innovative business models gain the status of iconic representations of particular types of firms. This study addresses the question: How do iconic business models emerge? In other words: How do innovative business models become prototypical exemplars for new categories of firms? We focus on the case of Airbnb, and analyze how six mainstream business media publications ...

A Power-Efficient Wireless Capacitor Charging System Through an Inductive Link.

Science.gov (United States)

Lee, Hyung-Min; Ghovanloo, Maysam

2013-10-01

A power-efficient wireless capacitor charging system for inductively powered applications has been presented. A bank of capacitors can be directly charged from an ac source by generating a current through a series charge injection capacitor and a capacitor charger circuit. The fixed charging current reduces energy loss in switches, while maximizing the charging efficiency. An adaptive capacitor tuner compensates for the resonant capacitance variations during charging to keep the amplitude of the ac input voltage at its peak. We have fabricated the capacitor charging system prototype in a 0.35- μ m 4-metal 2-poly standard CMOS process in 2.1 mm 2 of chip area. It can charge four pairs of capacitors sequentially. While receiving 2.7-V peak ac input through a 2-MHz inductive link, the capacitor charging system can charge each pair of 1 μ F capacitors up to ±2 V in 420 μ s, achieving a high measured charging efficiency of 82%.

Transition Icons for Time-Series Visualization and Exploratory Analysis.

Science.gov (United States)

Nickerson, Paul V; Baharloo, Raheleh; Wanigatunga, Amal A; Manini, Todd M; Tighe, Patrick J; Rashidi, Parisa

2018-03-01

The modern healthcare landscape has seen the rapid emergence of techniques and devices that temporally monitor and record physiological signals. The prevalence of time-series data within the healthcare field necessitates the development of methods that can analyze the data in order to draw meaningful conclusions. Time-series behavior is notoriously difficult to intuitively understand due to its intrinsic high-dimensionality, which is compounded in the case of analyzing groups of time series collected from different patients. Our framework, which we call transition icons, renders common patterns in a visual format useful for understanding the shared behavior within groups of time series. Transition icons are adept at detecting and displaying subtle differences and similarities, e.g., between measurements taken from patients receiving different treatment strategies or stratified by demographics. We introduce various methods that collectively allow for exploratory analysis of groups of time series, while being free of distribution assumptions and including simple heuristics for parameter determination. Our technique extracts discrete transition patterns from symbolic aggregate approXimation representations, and compiles transition frequencies into a bag of patterns constructed for each group. These transition frequencies are normalized and aligned in icon form to intuitively display the underlying patterns. We demonstrate the transition icon technique for two time-series datasets-postoperative pain scores, and hip-worn accelerometer activity counts. We believe transition icons can be an important tool for researchers approaching time-series data, as they give rich and intuitive information about collective time-series behaviors.

Iconicity as a general property of language: evidence from spoken and signed languages

Directory of Open Access Journals (Sweden)

Pamela Perniss

2010-12-01

Full Text Available Current views about language are dominated by the idea of arbitrary connections between linguistic form and meaning. However, if we look beyond the more familiar Indo-European languages and also include both spoken and signed language modalities, we find that motivated, iconic form-meaning mappings are, in fact, pervasive in language. In this paper, we review the different types of iconic mappings that characterize languages in both modalities, including the predominantly visually iconic mappings in signed languages. Having shown that iconic mapping are present across languages, we then proceed to review evidence showing that language users (signers and speakers exploit iconicity in language processing and language acquisition. While not discounting the presence and importance of arbitrariness in language, we put forward the idea that iconicity need also be recognized as a general property of language, which may serve the function of reducing the gap between linguistic form and conceptual representation to allow the language system to hook up to motor and perceptual experience.

The Iconic Chora: A Space of Kenotic Presence and Void

DEFF Research Database (Denmark)

Isar, Nicoletta

2000-01-01

and a cognitive theory that have proved incapable of explaining the endurance of the Byzantine scheme of the icon and of its oxymoronic (paradoxical) definition, except through an appeal to primitivism. I will attempt to put forward an alternative reading of the iconic space and show how vision itself......  The purpose of this essay is not exhaustive research concerning the iconic space and vision in Byzantium. Rather, the aim is to reshuffle the texts - from theological statements in defense of the image to liturgical, living ritual - to build up a polemical discourse with a tradition...

Bishnuprasad Rabha as Cultural Icon of Assam: The Process of Meaning Making

Directory of Open Access Journals (Sweden)

Parismita Hazarika

2017-03-01

Full Text Available Abstract The term ‘cultural icon’ is generally used to refer to individuals or images, objects, visual sign, monuments, space etc. In semiotics the term ‘icon’ is used to refer to a sign that bears close resemblance to the object that it stands for. Icons are particularly influential signifiers because they are immediately identifiable and carry complex cultural codes in a compact image. In this paper the understanding of ‘cultural icon’ is not limited to semiotics. Following Keyan Tomaselli and David Scott in Cultural Icons (2009, we believe that cultural icons are purposive constructions. An attempt has been made in this paper to analyze the association of ‘desirable’ meanings to a cultural icon (while dropping ‘undesirable’ ones; thus, it is imperative that we look at the changing socio-political contexts behind such purposive constructions. With this in mind, we look at the iconic figure of Bishnuprasad Rabha who has been one of the most revered figures in the cultural history of Assam and has been appropriated as a cultural icon in different discourses of the national life of Assam that has emerged in recent times.

Implanted Antennas in Medical Wireless Communications

CERN Document Server

Rahmat-Samii, Yahya; Balanis, Constantine

2006-01-01

Implanted Antennas in Medical Wireless Communications summarizes the results of recent research activities on the subject of implanted antennas for medical wireless communication systems. It is anticipated that in the near future sophisticated medical devices will be implanted inside the human body for medical telemetry and telemedicine. To establish effective and efficient wireless links with these devices, it is pivotal to give special attention to antenna designs that are low profile, small, safe, and cost effective. In this book, authors Yahya Rahmat-Samii and Jaehoon Kim demonstrate how a

Buckshot Routing with Distance Vectors in Three Application Scenarios for Wireless Sensor Networks with Unstable Network Topologies and Unidirectional Links

Directory of Open Access Journals (Sweden)

Reinhardt Karnapke

2015-02-01

Full Text Available Experiments have shown that the number of asymmetric and unidirectional links often exceeds the number of bidirectional ones, especially in the transitional area of the communication range of wireless sensor nodes. Still, most of today’s routing protocols ignore their existence or try to remove their implications. Also, links are not stable over time, and routes become unusable often, resulting in a need for new routing protocols that can handle highly dynamic links and use unidirectional links to their advantage. At SENSORCOMM' 2014, we presented BuckshotDV, a routing protocol which is resilient against link fluctuations and uses the longer reach of unidirectional links to increase its performance. Furthermore, its distance vector nature makes it scalable for large sensor networks. This paper is an extended version which adds some implementation details and the evaluation of BuckshotDV in two more application scenarios.

Photonic techniques for sub-Terahertz wireless data transmission

DEFF Research Database (Denmark)

Tafur Monroy, Idelfonso

2015-01-01

Wireless data communication links with capacities beyond 100 Gbit/s will require operating at sub-Terahertz frequencies using a large bandpass bandwidth facing new engineering challenges. We review several implementation aspects by using photonic technologies. © 2015 OSA.......Wireless data communication links with capacities beyond 100 Gbit/s will require operating at sub-Terahertz frequencies using a large bandpass bandwidth facing new engineering challenges. We review several implementation aspects by using photonic technologies. © 2015 OSA....

Message formulation, organization, and navigation schemes for icon-based communication aids.

Science.gov (United States)

Patel, Rupal

2011-01-01

Individuals with severe speech and motor impairments rely on assistive communication devices to convey their needs and desires in social, educational, and vocational situations. Users with limited motor control or literacy often choose to use icon-based devices that afford increased speed of message formulation at the cost of fully generative language formulation on letter-based devices. A major challenge with large vocabulary icon-based systems is rate of communication. Message formulation, vocabulary organization, and navigation schemes can be used to mitigate the trade-off between vocabulary size and communication rate. This paper summarizes our research efforts to leverage semantic frame theory, situational context, and rapid serial visual presentation to improve message formulation speed and completeness in our iconCHAT and RSVP iconCHAT systems. Usability data and persisting challenges are discussed.

Iconic gestures prime related concepts: an ERP study.

Science.gov (United States)

Wu, Ying Croon; Coulson, Seana

2007-02-01

To assess priming by iconic gestures, we recorded EEG (at 29 scalp sites) in two experiments while adults watched short, soundless videos of spontaneously produced, cospeech iconic gestures followed by related or unrelated probe words. In Experiment 1, participants classified the relatedness between gestures and words. In Experiment 2, they attended to stimuli, and performed an incidental recognition memory test on words presented during the EEG recording session. Event-related potentials (ERPs) time-locked to the onset of probe words were measured, along with response latencies and word recognition rates. Although word relatedness did not affect reaction times or recognition rates, contextually related probe words elicited less-negative ERPs than did unrelated ones between 300 and 500 msec after stimulus onset (N400) in both experiments. These findings demonstrate sensitivity to semantic relations between iconic gestures and words in brain activity engendered during word comprehension.

Introductory survey for wireless infrared communications

Directory of Open Access Journals (Sweden)

Munsif Ali Jatoi

2014-08-01

Full Text Available Wireless infrared communications can be defined as the propagation of light waves in free space using infrared radiation whose range is 400–700 nm. This range corresponds to frequencies of hundreds of terahertz, which is high for higher data rate applications. Wireless infrared is applied for higher data rates applications such as wireless computing, wireless video and wireless multimedia communication applications. Introduced by Gfeller, this field has grown with different link configurations, improved transmitter efficiency, increased receiver responsivity and various multiple access techniques for improved quality. Errors are caused because of background light, which causes degradation overall system performance. Error correction techniques are used to remove the errors caused during transmission. This study provides a brief account on field theory used for error correction in wireless infrared systems. The results are produced in terms of bit error rate and signal-to-noise ratio for various bit lengths to show the ability of encoding and decoding algorithms.

Comment: 219 [Taxonomy Icon

Lifescience Database Archive (English)

Full Text Available Japanese medaka Oryzias latipes Oryzias_latipes_L.png 219.png Taxonomy icon (c) Database Center for Life Sci...ence licensed under CC Attribution2.1 Japan アイコン:メダカ HNI-Ⅱ系統バージョン bando 2010/02/15 15:31:07 2010/02/16 09:53:27 ...

Read-out of emotional information from iconic memory: the longevity of threatening stimuli.

Science.gov (United States)

Kuhbandner, Christof; Spitzer, Bernhard; Pekrun, Reinhard

2011-05-01

Previous research has shown that emotional stimuli are more likely than neutral stimuli to be selected by attention, indicating that the processing of emotional information is prioritized. In this study, we examined whether the emotional significance of stimuli influences visual processing already at the level of transient storage of incoming information in iconic memory, before attentional selection takes place. We used a typical iconic memory task in which the delay of a poststimulus cue, indicating which of several visual stimuli has to be reported, was varied. Performance decreased rapidly with increasing cue delay, reflecting the fast decay of information stored in iconic memory. However, although neutral stimulus information and emotional stimulus information were initially equally likely to enter iconic memory, the subsequent decay of the initially stored information was slowed for threatening stimuli, a result indicating that fear-relevant information has prolonged availability for read-out from iconic memory. This finding provides the first evidence that emotional significance already facilitates stimulus processing at the stage of iconic memory.

Nonlinear Optimization-Based Device-Free Localization with Outlier Link Rejection

Directory of Open Access Journals (Sweden)

Wendong Xiao

2015-04-01

Full Text Available Device-free localization (DFL is an emerging wireless technique for estimating the location of target that does not have any attached electronic device. It has found extensive use in Smart City applications such as healthcare at home and hospitals, location-based services at smart spaces, city emergency response and infrastructure security. In DFL, wireless devices are used as sensors that can sense the target by transmitting and receiving wireless signals collaboratively. Many DFL systems are implemented based on received signal strength (RSS measurements and the location of the target is estimated by detecting the changes of the RSS measurements of the wireless links. Due to the uncertainty of the wireless channel, certain links may be seriously polluted and result in erroneous detection. In this paper, we propose a novel nonlinear optimization approach with outlier link rejection (NOOLR for RSS-based DFL. It consists of three key strategies, including: (1 affected link identification by differential RSS detection; (2 outlier link rejection via geometrical positional relationship among links; (3 target location estimation by formulating and solving a nonlinear optimization problem. Experimental results demonstrate that NOOLR is robust to the fluctuation of the wireless signals with superior localization accuracy compared with the existing Radio Tomographic Imaging (RTI approach.

A Wireless Implantable Switched-Capacitor Based Optogenetic Stimulating System

Science.gov (United States)

Lee, Hyung-Min; Kwon, Ki-Yong; Li, Wen

2015-01-01

This paper presents a power-efficient implantable optogenetic interface using a wireless switched-capacitor based stimulating (SCS) system. The SCS efficiently charges storage capacitors directly from an inductive link and periodically discharges them into an array of micro-LEDs, providing high instantaneous power without affecting wireless link and system supply voltage. A custom-designed computer interface in LabVIEW environment wirelessly controls stimulation parameters through the inductive link, and an optrode array enables simultaneous neural recording along with optical stimulation. The 4-channel SCS system prototype has been implemented in a 0.35-μm CMOS process and combined with the optrode array. In vivo experiments involving light-induced local field potentials verified the efficacy of the SCS system. An implantable version of the SCS system with flexible hermetic sealing is under development for chronic experiments. PMID:25570099

What is a missing link among wireless persistent surveillance?

Science.gov (United States)

Hsu, Charles; Szu, Harold

2011-06-01

The next generation surveillance system will equip with versatile sensor devices and information focus capable of conducting regular and irregular surveillance and security environments worldwide. The community of the persistent surveillance must invest the limited energy and money effectively into researching enabling technologies such as nanotechnology, wireless networks, and micro-electromechanical systems (MEMS) to develop persistent surveillance applications for the future. Wireless sensor networks can be used by the military for a number of purposes such as monitoring militant activity in remote areas and force protection. Being equipped with appropriate sensors these networks can enable detection of enemy movement, identification of enemy force and analysis of their movement and progress. Among these sensor network technologies, covert communication is one of the challenging tasks in the persistent surveillance because it is highly demanded to provide secured sensor nodes and linkage for fear of deliberate sabotage. Due to the matured VLSI/DSP technologies, affordable COTS of UWB technology with noise-like direct sequence (DS) time-domain pulses is a potential solution to support low probability of intercept and low probability of detection (LPI/LPD) data communication and transmission. This paper will describe a number of technical challenges in wireless persistent surveillance development include covert communication, network control and routing, collaborating signal and information processing, and etc. The paper concludes by presenting Hermitian Wavelets to enhance SNR in support of secured communication.

Wireless Communications in the Era of Big Data

OpenAIRE

Bi, Suzhi; Zhang, Rui; Ding, Zhi; Cui, Shuguang

2015-01-01

© 1979-2012 IEEE. The rapidly growing wave of wireless data service is pushing against the boundary of our communication network's processing power. The pervasive and exponentially increasing data traffic present imminent challenges to all aspects of wireless system design, such as spectrum efficiency, computing capabilities, and fronthaul/backhaul link capacity. In this article, we discuss the challenges and opportunities in the design of scalable wireless systems to embrace the big data era...

Seeing iconic gestures while encoding events facilitates children's memory of these events

OpenAIRE

Aussems, Suzanne; Kita, Sotaro

2017-01-01

An experiment with 72 three-year-olds investigated whether encoding events while seeing iconic gestures boosts children's memory representation of these events. The events, shown in videos of actors moving in an unusual manner, were presented with either iconic gestures depicting how the actors performed these actions, interactive gestures, or no gesture. In a recognition memory task, children in the iconic gesture condition remembered actors and actions better than children in the control co...

Wireless Device-to-Device (D2D) Links for Machine-to-Machine (M2M) Communication

DEFF Research Database (Denmark)

Pratas, Nuno; Popovski, Petar

2017-01-01

Device-to-Device (D2D) communications will play an important role in the fifth generation (5G) cellular networks, by increasing the spatial reuse of spectrum resources and enabling communication links with low latency. D2D is composed of two fundamental building blocks: proximity discovery...... and direct communication between nearby users. Another emerging trend in wireless cellular systems is Machine-to-Machine (M2M) communications, often characterized by fixed, low transmission rates. In this chapter we motivate the synergy between D2D and M2M, and present technologies that enable M2M-via-D2D...

Two-Step Fair Scheduling of Continuous Media Streams over Error-Prone Wireless Channels

Science.gov (United States)

Oh, Soohyun; Lee, Jin Wook; Park, Taejoon; Jo, Tae-Chang

In wireless cellular networks, streaming of continuous media (with strict QoS requirements) over wireless links is challenging due to their inherent unreliability characterized by location-dependent, bursty errors. To address this challenge, we present a two-step scheduling algorithm for a base station to provide streaming of continuous media to wireless clients over the error-prone wireless links. The proposed algorithm is capable of minimizing the packet loss rate of individual clients in the presence of error bursts, by transmitting packets in the round-robin manner and also adopting a mechanism for channel prediction and swapping.

The Prospects of Ultra-Broadband THz Wireless Communications

DEFF Research Database (Denmark)

Yu, Xianbin; Chen, Ying; Galili, Michael

2014-01-01

Wireless communications have entered into a path towards Terabit era, to accommodate the increasing demands on fast wireless access, e.g. huge data file transferring and fast mobile data access. Terahertz (THz) technology is considered feasible to carry ultrafast data signals, as it offers up...... to a few THz bandwidths. This paper overviews the prospects of Tbit/s wireless data rate and their potential applications. Technically, this talk reviews the key technologies and challenges to achieve an ultrafast wireless system operating in the THz frequency band, from viewpoint of communication......, in terms of ultrafast THz generation/THz detection and link power budget....

Information Assurance in Wireless Networks

Science.gov (United States)

Kabara, Joseph; Krishnamurthy, Prashant; Tipper, David

2001-09-01

Emerging wireless networks will contain a hybrid infrastructure based on fixed, mobile and ad hoc topologies and technologies. In such a dynamic architecture, we define information assurance as the provisions for both information security and information availability. The implications of this definition are that the wireless network architecture must (a) provide sufficient security measures, (b) be survivable under node or link attack or failure and (c) be designed such that sufficient capacity remains for all critical services (and preferably most other services) in the event of attack or component failure. We have begun a research project to investigate the provision of information assurance for wireless networks viz. survivability, security and availability and here discuss the issues and challenges therein.

Iconic Meaning in Music: An Event-Related Potential Study.

Science.gov (United States)

Cai, Liman; Huang, Ping; Luo, Qiuling; Huang, Hong; Mo, Lei

2015-01-01

Although there has been extensive research on the processing of the emotional meaning of music, little is known about other aspects of listeners' experience of music. The present study investigated the neural correlates of the iconic meaning of music. Event-related potentials (ERP) were recorded while a group of 20 music majors and a group of 20 non-music majors performed a lexical decision task in the context of implicit musical iconic meaning priming. ERP analysis revealed a significant N400 effect of congruency in time window 260-510 ms following the onset of the target word only in the group of music majors. Time-course analysis using 50 ms windows indicated significant N400 effects both within the time window 410-460 ms and 460-510 ms for music majors, whereas only a partial N400 effect during time window 410-460 ms was observed for non-music majors. There was also a trend for the N400 effects in the music major group to be stronger than those in the non-major group in the sub-windows of 310-360 ms and 410-460 ms. Especially in the sub-window of 410-460 ms, the topographical map of the difference waveforms between congruent and incongruent conditions revealed different N400 distribution between groups; the effect was concentrated in bilateral frontal areas for music majors, but in central-parietal areas for non-music majors. These results imply probable neural mechanism differences underlying automatic iconic meaning priming of music. Our findings suggest that processing of the iconic meaning of music can be accomplished automatically and that musical training may facilitate the understanding of the iconic meaning of music.

Iconic Religion in Urban Space

NARCIS (Netherlands)

Meyer, B.; Knott, Kim; Krech, Volkhard

2016-01-01

In order to understand current dynamics of religious diversity, a focus on the tangible presence of religion and the co-existence of new and longstanding religious buildings, sites and artifacts in urban spaces is a fruitful starting point. Launching the notion of iconic religion, this introduction

No iconic memory without attention.

Science.gov (United States)

Mack, Arien; Erol, Muge; Clarke, Jason; Bert, John

2016-02-01

The experiments reported extend the findings of our earlier paper, (Mack, Erol, & Clarke, 2015) and allow us to reject Bachmann and Aru's critique of our conclusion (2015) that IM requires attention. They suggested our manipulations, which diverted attention from a letter reporting task in a dual task procedure where the task-cue occurred after the array disappeared, might only have affected access to IM and not the "existence of the phenomenal experience". By further decreasing the probability of reporting letters to only 10% and adding a final trial in which the letter matrix was either completely absent or distorted, we found more than half our subjects were unaware of its absence, or distortion i.e., were inattentionally blind. We take this as powerful evidence against the existence of any phenomenal experience component of iconic memory and consistent with the view that iconic memory demands attention and that conscious perception does as well. Copyright © 2015 Elsevier Inc. All rights reserved.

Adaptive Protocols for Mobile Wireless Networks

National Research Council Canada - National Science Library

Pursley, Michael B

2005-01-01

.... Research results are presented on adaptive, energy-efficient, distributed protocols for mobile wireless networks that must operate effectively over unreliable communication links in highly dynamic...

Multigigabit W-Band (75–110 GHz) Bidirectional Hybrid Fiber-Wireless Systems in Access Networks

DEFF Research Database (Denmark)

Pang, Xiaodan; Lebedev, Alexander; Vegas Olmos, Juan José

2014-01-01

compare the transmission performances in terms of achievable wireless distances with and without using a high-frequency electrical power amplifier at the wireless transmitter. A downlink 16-Gbit/s QPSK signal and an uplink 1.25-Gbit/s ASK signal transmission over the two implementations are experimentally......We experimentally demonstrate multigigabit capacity bidirectional hybrid fiber-wireless systems with RF carrier frequencies at the W-band (75-110 GHz) that enables the seamless convergence between wireless and fiber-optic data transmission systems in access networks. In this study, we evaluate...... the transmission performances in two scenarios: a fiber-wireless access link that directly provide high-speed connections to wireless end users, and a fiber-wireless-fiber signal relay where a high capacity wireless link can be used to bridge two access fiber spans over physical obstacles. In both scenarios, we...

Underwater Optical Wireless Communications, Networking, and Localization: A Survey

KAUST Repository

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2018-01-01

Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

Underwater Optical Wireless Communications, Networking, and Localization: A Survey

KAUST Repository

Saeed, Nasir

2018-02-28

Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

Infrared wireless data transfer for real-time motion control

NARCIS (Netherlands)

Gajdusek, M.; Overboom, T.T.; Damen, A.A.H.; Bosch, van den P.P.J.

2009-01-01

In this paper several wireless solution are compared for their suitability for real-time control of a fast motion system. From the comparison, Very Fast Infrared (VFIR) communication link has been found to be an attractive solution for presented wirelessly controlled manipulator. Because standard

Combining Semantic and Lexical Methods for Mapping MedDRA to VCM Icons.

Science.gov (United States)

Lamy, Jean-Baptiste; Tsopra, Rosy

2018-01-01

VCM (Visualization of Concept in Medicine) is an iconic language that represents medical concepts, such as disorders, by icons. VCM has a formal semantics described by an ontology. The icons can be used in medical software for providing a visual summary or enriching texts. However, the use of VCM icons in user interfaces requires to map standard medical terminologies to VCM. Here, we present a method combining semantic and lexical approaches for mapping MedDRA to VCM. The method takes advantage of the hierarchical relations in MedDRA. It also analyzes the groups of lemmas in the term's labels, and relies on a manual mapping of these groups to the concepts in the VCM ontology. We evaluate the method on 50 terms. Finally, we discuss the method and suggest perspectives.

Wireless communication for hearing aid system

DEFF Research Database (Denmark)

Nour, Baqer

This thesis focuses on the wireless coupling between hearing aids close to a human head. Hearing aids constitute devices withadvanced technology and the wireless communication enables the introduction of a range of completely new functionalities. Such devices are small and the available power...... the ear-to-ear wireless communication channel by understanding the mechanisms that control the propagations of the signals and the losses. The second objective isto investigate the properties of magneto-dielectric materials and their potential in antenna miniaturization. There are three approaches...... to study the ear-to-ear wireless communication link; a theoretical approach models the human head asa sphere that has the electrical properties of the head, a numerical approach implements a more realistic geometry of the head, and an experimental approach measures directly the coupling between...

Effects of pyrethroid insecticide ICON (lambda cyhalothrin) on reproductive competence of male rats.

Science.gov (United States)

Ratnasooriya, W D; Ratnayake, S S K; Jayatunga, Y N A

2002-03-01

To assess the effect of ICON (trade name of lambda-cyhalothrin) on sexual competence and fertility of male rats. Male rats were gavaged daily for 7 consecutive days with different doses of ICON (63 mg/kg and 100 mg/kg) or vehicle (distilled water). Their sexual behaviour and fertility were evaluated at different time points during treatment and post-treatment using receptive females. Treatment had no effect on fertility, but sexual competence was seriously impaired: libido (assessed in terms of pre-coital sexual behaviour, and numbers of mounting, intromission and ejaculation), sexual arousability/motivation (in terms of latencies for mounting, intromission and ejaculation), sexual vigour (judged by frequencies of mounting and intromission or copulatory efficiency). In addition, ICON suppressed intromission ratio, indicating erectile dysfunction. These effects on sexual function had a rapid onset and was reversible. ICON-induced sexual dysfunction was mediated by multiple mechanisms, mainly toxicity, stress, sedation and possibly via GABA and dopaminergic systems. Exposure to ICON may cause sexual dysfunction in male rats.

Iconic Meaning in Music: An Event-Related Potential Study

Science.gov (United States)

Luo, Qiuling; Huang, Hong; Mo, Lei

2015-01-01

Although there has been extensive research on the processing of the emotional meaning of music, little is known about other aspects of listeners’ experience of music. The present study investigated the neural correlates of the iconic meaning of music. Event-related potentials (ERP) were recorded while a group of 20 music majors and a group of 20 non-music majors performed a lexical decision task in the context of implicit musical iconic meaning priming. ERP analysis revealed a significant N400 effect of congruency in time window 260-510 ms following the onset of the target word only in the group of music majors. Time-course analysis using 50 ms windows indicated significant N400 effects both within the time window 410-460 ms and 460-510 ms for music majors, whereas only a partial N400 effect during time window 410-460 ms was observed for non-music majors. There was also a trend for the N400 effects in the music major group to be stronger than those in the non-major group in the sub-windows of 310-360ms and 410-460ms. Especially in the sub-window of 410-460 ms, the topographical map of the difference waveforms between congruent and incongruent conditions revealed different N400 distribution between groups; the effect was concentrated in bilateral frontal areas for music majors, but in central-parietal areas for non-music majors. These results imply probable neural mechanism differences underlying automatic iconic meaning priming of music. Our findings suggest that processing of the iconic meaning of music can be accomplished automatically and that musical training may facilitate the understanding of the iconic meaning of music. PMID:26161561

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

OpenAIRE

Ben Minnaert; Nobby Stevens

2017-01-01

Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this opti...

An icon that everyone wants to click on : an empirical study on the relationship between consumer perceptions and mobile game icon successfulness

OpenAIRE

Jylhä, Henrietta

2017-01-01

Mobile games market has been touted as the fastest growing gaming sector in the world. Every day thousands of new mobile games are published to join millions of others on app stores. The competition for top grossing mobile games is fierce, and the way a game is represented greatly contributes to its commercial success. When browsing for mobile games, consumers search for an icon they want to click on. However, most mobile games fail to engage consumers who browse past hundreds of icons on app...

Combined single-mode/multimode fiber link supporting simplified in-building 60-GHz gigabit wireless access

DEFF Research Database (Denmark)

Pham, Tien Thang; Lebedev, Alexander; Beltrán, Marta

2012-01-01

In this paper, we propose and experimentally demonstrate a simple, cost-effective hybrid gigabit fiber-wireless system for in-building wireless access. Simplicity and cost-effectiveness are achieved in all parts of the system by utilizing direct laser modulation, optical frequency up-conversion, ......In this paper, we propose and experimentally demonstrate a simple, cost-effective hybrid gigabit fiber-wireless system for in-building wireless access. Simplicity and cost-effectiveness are achieved in all parts of the system by utilizing direct laser modulation, optical frequency up...

The icon of the Holy Virgin Vatopedini with a portrait of Voevoda Ioan Radul

Directory of Open Access Journals (Sweden)

Mašnić Mirjana M.

2003-01-01

Full Text Available In this article, the author discusses iconography and stylistic characteristic of the icon featuring the Virgin Vatopedini with the Hungarian-Wallachian Voevoda loan Radul. The icon is treasured in the cathedral church of the Holy martyr Demetrios in Bitola. In more recent times, a new layer was painted over the icon, but not so long ago the icon was restored to its original condition. The inscriptions on the icon reveal that the Voevoda was a "new ktetor" of Vatopedi and also testify the painting was completed on November 28, 1502. The representation of the enthroned Virgin with the infant Christ sitting in her lap, flanked by St John Prodromes and the founder, belongs to the iconography of Deesis. Its stylistic features indicate that in most probability it was the work by a Cretan painter from the Ritzos family.

Reactor building indoor wireless network channel quality estimation using RSSI measurement of wireless sensor network

International Nuclear Information System (INIS)

Merat, S.

2008-01-01

Expanding wireless communication network reception inside reactor buildings (RB) and service wings (SW) has always been a technical challenge for operations service team. This is driven by the volume of metal equipment inside the Reactor Buildings (RB) that blocks and somehow shields the signal throughout the link. In this study, to improve wireless reception inside the Reactor Building (RB), an experimental model using indoor localization mesh based on IEEE 802.15 is developed to implement a wireless sensor network. This experimental model estimates the distance between different nodes by measuring the RSSI (Received Signal Strength Indicator). Then by using triangulation and RSSI measurement, the validity of the estimation techniques is verified to simulate the physical environmental obstacles, which block the signal transmission. (author)

Reactor building indoor wireless network channel quality estimation using RSSI measurement of wireless sensor network

Energy Technology Data Exchange (ETDEWEB)

Merat, S. [Wardrop Engineering Inc., Toronto, Ontario (Canada)

2008-07-01

Expanding wireless communication network reception inside reactor buildings (RB) and service wings (SW) has always been a technical challenge for operations service team. This is driven by the volume of metal equipment inside the Reactor Buildings (RB) that blocks and somehow shields the signal throughout the link. In this study, to improve wireless reception inside the Reactor Building (RB), an experimental model using indoor localization mesh based on IEEE 802.15 is developed to implement a wireless sensor network. This experimental model estimates the distance between different nodes by measuring the RSSI (Received Signal Strength Indicator). Then by using triangulation and RSSI measurement, the validity of the estimation techniques is verified to simulate the physical environmental obstacles, which block the signal transmission. (author)

Cross-Layer Wireless Resource Allocation

National Research Council Canada - National Science Library

Berry, Randall A; Yeh, Edmund M

2005-01-01

.... This bit pipe is a simple abstraction of the underlying physical and data link layers. There is growing awareness that this simple bit-pipe view is inadequate, particularly in the context of modern wireless data networks...

Bandwidth enhancement of wireless optical communication link using a near-infrared laser over turbid underwater channel

KAUST Repository

Lee, It Ee

2017-11-30

Underwater wireless optical communication (UWOC) has been widely studied as a promising alternative to establish reliable short-range marine communication links. Microscopic particulates suspended in various ocean, harbor and natural waters will alter the propagation characteristics of the optical signals underwater. In this paper, we demonstrate a gigabit near-infrared (NIR)-based UWOC link using an 808-nm laser diode, to examine the feasibility of the proposed system in mitigating the particle scattering effect over turbid waters. We show that the NIR wavelengths presents greater resilience to the aqueous suspension of these micro-sized particles with a smaller scattering effect due to its longer wavelength, as evident by the smaller variations in the optical beam transmittance. It is also observed that the error performance is improved at higher concentrations albeit the significant reduction in received signal power. We further demonstrate that the overall frequency response of the system exhibits a bandwidth enhancement up to a few tens of MHz with increasing concentrations.

Remote Access Unit for Optic-to-Wireless Conversion

DEFF Research Database (Denmark)

Chorchos, Łukasz; Rommel, Simon; Turkiewicz, J. P.

. Growing demand for high speed wireless data transmission and new wireless standards like 5G force network operators to find new solutions for backhaul networks. Presently, to meet this need, attention of many researchers and top network vendors has been directed towards millimeter wave radio links....... Operation in the millimeter wave range brings new possibilities for a channel allocation as well as allows wider radio channels to be used. Moreover this frequency range is lighter licensed than regular GSM. This clearly shows a huge potential of millimeter waves for a high speed wireless data transmission...... was proposed and research projects like IPHOBAC-NG were founded. The aim of the mentioned project is to employ novel RAUs featuring opticto-wireless and wireless-to-optic conversion with a speeds of 1-10Gbit/s for broadband wireless access and up to 3Gbit/s for mobile backhaul. The RAU proposed in this paper...

Bluetooth low energy: wireless connectivity for medical monitoring.

Science.gov (United States)

Omre, Alf Helge

2010-03-01

Electronic wireless sensors could cut medical costs by enabling physicians to remotely monitor vital signs such as blood pressure, blood glucose, and blood oxygenation while patients remain at home. According to the IDC report "Worldwide Bluetooth Semiconductor 2008-2012 Forecast," published November 2008, a forthcoming radio frequency communication ("wireless connectivity") standard, Bluetooth low energy, will link wireless sensors via radio signals to the 70% of cell phones and computers likely to be fitted with the next generation of Bluetooth wireless technology, leveraging a ready-built infrastructure for data transmission. Analysis of trends indicated by this data can help physicians better manage diseases such as diabetes. The technology also addresses the concerns of cost, compatibility, and interoperability that have previously stalled widespread adoption of wireless technology in medical applications. (c) 2010 Diabetes Technology Society.

LinkMind: link optimization in swarming mobile sensor networks.

Science.gov (United States)

Ngo, Trung Dung

2011-01-01

A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation.

LinkMind: Link Optimization in Swarming Mobile Sensor Networks

Directory of Open Access Journals (Sweden)

Trung Dung Ngo

2011-08-01

Full Text Available A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation.

Fast decay of iconic memory in observers with mild cognitive impairments.

Science.gov (United States)

Lu, Zhong-Lin; Neuse, James; Madigan, Stephen; Dosher, Barbara Anne

2005-02-01

In a previous clinical report, unusually fast decay of iconic memory was obtained from a subject who later developed Alzheimer's disease. By using the partial-report paradigm, iconic memory (a form of visual sensory memory) in a group of observers with mild cognitive impairments (MCI) was characterized and compared with that of young college-age adults and older controls. Relatively long stimulus exposures were used for all three groups to ensure that older observers could perceive the stimuli. A set of conventional neuropsychological tests assessed cognitive functions of the MCI and older control groups. We found that iconic memory decayed much faster for observers with MCI than for normal controls, old or young, although the two groups of older observers performed at equivalent levels in precue tests (assay of visibility) and tests cued at long delays (assay of short-term memory). The result suggests that fast decay of iconic memory might be a general characteristic of observers with MCI who are at much higher than average risk of developing Alzheimer's disease later in life.

Combined dendrochronological and radiocarbon dating of six Russian icons from the 15th-17th centuries

Science.gov (United States)

Dolgikh, A. V.; Matskovsky, V. V.; Voronin, K. V.; Solomina, O. N.

2017-06-01

The results of dendrochronological and radiocarbon dating by means of accelerator mass spectrometry (AMS) of six medieval icons, originating from northern European Russia and painted on wooden panels made from Scots pine, dated to the 15th to 17th centuries are presented. The panels of each icon were studied using dendrochronology. Five to six AMS dates were obtained for four icons. Although five icons were dendro-dated successfully, one failed to be reliably cross-dated with the existing master tree-ring chronologies and it was dated by radiocarbon wiggle-matching. Dendrochronological dating and wiggle-matching of radiocarbon dates allowed us to determine the narrow chronological intervals of icon creation.

Heterogeneous wireless/wireline optical access networks with the R-EAT as backend component

Science.gov (United States)

Hagedorn, Klaus; Gindera, Ralf; Stohr, Andreas; Jager, Dieter

2004-09-01

A heterogeneous wireless/wireline optical transmission link using a reflection type electroabsorption transceiver (R-EAT) is presented. Simultaneous transmission of full-duplex broadband wireless LAN (WLAN) channels and 1Gb/s base band data is experimentally demonstrated. The system link employs sub-carrier multiplexing (SCM) and two optical channels for full duplex transmission of various analog WLAN channels and downlink digital base band data. The developed link architecture is suitable for simultaneous transmission of broadband wireline and wireless signals, it enables the coexistence and interoperability between wireline and wireless access technologies. The developed R-EAT component employed in this wireline/wireless access system, features "single-chip-component" base stations in access networks with star type topology where only a single optical fiber is used for bidirectional optical transmission. The R-EAT can be used within the optical C-band (1530- 1560nm) and is suitable for (D)WDM networks. Bit error rate measurements demonstrate the capabilities of the R-EAT for 1Gb/s base band transmission. The analog performance for WLAN transmission is characterised by a spurious free dynamic range (SFDR) of more than 75dB and 90dB for uplink and downlink transmission, respectively. The link gain for uplink and downlink transmission is -42dB and -37dB, respectively. The demonstrates the analog performances of the R-EAT for being used in wireless access networks such as W-LAN.

Fundamental Analysis of Extremely Fast Photonic THz Wireless Communication Systems

DEFF Research Database (Denmark)

Yu, Xianbin; Zhang, Xianmin

This talk will review the recent progress on developing THz communication systems for high speed wireless access, and fundamentally analyze the realistic throughput and accessible wireless range of a THz impulse radio communication link by employing a uni-travelling photodiode (UTC-PD) as emitter...

Wireless neural recording with single low-power integrated circuit.

Science.gov (United States)

Harrison, Reid R; Kier, Ryan J; Chestek, Cynthia A; Gilja, Vikash; Nuyujukian, Paul; Ryu, Stephen; Greger, Bradley; Solzbacher, Florian; Shenoy, Krishna V

2009-08-01

We present benchtop and in vivo experimental results from an integrated circuit designed for wireless implantable neural recording applications. The chip, which was fabricated in a commercially available 0.6- mum 2P3M BiCMOS process, contains 100 amplifiers, a 10-bit analog-to-digital converter (ADC), 100 threshold-based spike detectors, and a 902-928 MHz frequency-shift-keying (FSK) transmitter. Neural signals from a selected amplifier are sampled by the ADC at 15.7 kSps and telemetered over the FSK wireless data link. Power, clock, and command signals are sent to the chip wirelessly over a 2.765-MHz inductive (coil-to-coil) link. The chip is capable of operating with only two off-chip components: a power/command receiving coil and a 100-nF capacitor.

VT Wireless Internet Service Providers 2006

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VT Wireless Internet Service Provider (ISP) dataset (WISP2006) includes polygons depicting the extent of Vermont's WISP broadband system as of...

VT Wireless Internet Service Providers 2007

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VT Wireless Internet Service Provider (ISP) dataset (WISP2007) includes polygons depicting the extent of Vermont's WISP broadband system as of...

Affixes, Austronesian and iconicity in Malay

Directory of Open Access Journals (Sweden)

Geoffrey Benjamin

2009-10-01

Full Text Available Explanations are offered for the puzzling differences between the forms and meanings of the Malay affixes and those of the broader Austronesian affixal system from which they derive. Oral-gesture iconicity is involved in the encoding of meanings that have both language-internal and social significance. The various verbal prefixes can be analysed both historically and iconically as different combinations of (1 a labial series (m , b , p indicating ‘source orientation’ with (2 r ‘iterative’ and (3 ( N ‘process marker’. The full range of forms becomes apparent only if a sufficiently wide range of Malay and Malayic speech-varieties, both ancient and modern, are brought to bear on the discussion. The different meanings and functions associated with the various prefixes are motivated by the different semantic concerns engendered by the social and cultural circumstances peculiar to each of the speech-varieties.

Optical wireless communications for micromachines

Science.gov (United States)

O'Brien, Dominic C.; Yuan, Wei Wen; Liu, Jing Jing; Faulkner, Grahame E.; Elston, Steve J.; Collins, Steve; Parry-Jones, Lesley A.

2006-08-01

A key challenge for wireless sensor networks is minimizing the energy required for network nodes to communicate with each other, and this becomes acute for self-powered devices such as 'smart dust'. Optical communications is a potentially attractive solution for such devices. The University of Oxford is currently involved in a project to build optical wireless links to smart dust. Retro-reflectors combined with liquid crystal modulators can be integrated with the micro-machine to create a low power transceiver. When illuminated from a base station a modulated beam is returned, transmitting data. Data from the base station can be transmitted using modulation of the illuminating beam and a receiver at the micro-machine. In this paper we outline the energy consumption and link budget considerations in the design of such micro-machines, and report preliminary experimental results.

Propagation Engineering in Wireless Communications

CERN Document Server

Ghasemi, Abdollah; Ghasemi, Farshid

2012-01-01

Wireless communications has seen explosive growth in recent decades, in a realm that is both broad and rapidly expanding to include satellite services, navigational aids, remote sensing, telemetering, audio and video broadcasting, high-speed data communications, mobile radio systems and much more. Propagation Engineering in Wireless Communications deals with the basic principles of radiowaves propagation for frequency bands used in radio-communications, offering descriptions of new achievements and newly developed propagation models. The book bridges the gap between theoretical calculations and approaches, and applied procedures needed for advanced radio links design. The primary objective of this two-volume set is to demonstrate the fundamentals, and to introduce propagation phenomena and mechanisms that engineers are likely to encounter in the design and evaluation of radio links of a given type and operating frequency. Volume one covers basic principles, along with tropospheric and ionospheric propagation,...

Virtual Lab for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

PICOVICI, D.

2008-06-01

Full Text Available This article details an experimental system developed to enhance the education and research in the area of wireless networks technologies. The system referred, as Virtual Lab (VL is primarily targeting first time users or users with limited experience in programming and using wireless sensor networks. The VL enables a set of predefined sensor networks to be remotely accessible and controlled for constructive and time-efficient experimentation. In order to facilitate the user's wireless sensor applications, the VL is using three main components: a a Virtual Lab Motes (VLM, representing the wireless sensor, b a Virtual Lab Client (VLC, representing the user's tool to interact with the VLM and c a Virtual Lab Server (VLS representing the software link between the VLM and VLC. The concept has been proven using the moteiv produced Tmote Sky modules. Initial experimental use clearly demonstrates that the VL approach reduces dramatically the learning curve involved in programming and using the associated wireless sensor nodes. In addition the VL allows the user's focus to be directed towards the experiment and not towards the software programming challenges.

Readout from iconic memory and selective spatial attention involve similar neural processes.

Science.gov (United States)

Ruff, Christian C; Kristjánsson, Arni; Driver, Jon

2007-10-01

Iconic memory and spatial attention are often considered separately, but they may have functional similarities. Here we provide functional magnetic resonance imaging evidence for some common underlying neural effects. Subjects judged three visual stimuli in one hemifield of a bilateral array comprising six stimuli. The relevant hemifield for partial report was indicated by an auditory cue, administered either before the visual array (precue, spatial attention) or shortly after the array (postcue, iconic memory). Pre- and postcues led to similar activity modulations in lateral occipital cortex contralateral to the cued side. This finding indicates that readout from iconic memory can have some neural effects similar to those of spatial attention. We also found common bilateral activation of a fronto-parietal network for postcue and precue trials. These neuroimaging data suggest that some common neural mechanisms underlie selective spatial attention and readout from iconic memory. Some differences were also found; compared with precues, postcues led to higher activity in the right middle frontal gyrus.

OPTICAL WIRELESS COMMUNICATION SYSTEM

Directory of Open Access Journals (Sweden)

JOSHUA L.Y. CHIENG

2016-02-01

Full Text Available The growing demand of bandwidth in this modern internet age has been testing the existing telecommunication infrastructures around the world. With broadband speeds moving towards the region of Gbps and Tbps, many researches have begun on the development of using optical wireless technology as feasible and future methods to the current wireless technology. Unlike the existing radio frequency wireless applications, optical wireless uses electromagnetic spectrums that are unlicensed and free. With that, this project aim to understand and gain better understanding of optical wireless communication system by building an experimental and simulated model. The quality of service and system performance will be investigated and reviewed. This project employs laser diode as the propagation medium and successfully transferred audio signals as far as 15 meters. On its quality of service, results of the project model reveal that the bit error rate increases, signal-to-noise ratio and quality factor decreases as the link distance between the transmitter and receiver increases. OptiSystem was used to build the simulated model and MATLAB was used to assist signal-to-noise ratio calculations. By comparing the simulated and experimental receiver’s power output, the experimental model’s efficiency is at 66.3%. Other than the system’s performance, challenges and factors affecting the system have been investigated and discussed. Such challenges include beam divergence, misalignment and particle absorption.

Channel characterization for high-speed W-band wireless communication links

DEFF Research Database (Denmark)

Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José

2015-01-01

We present and discuss results from an experimental characterization of the W-band indoor wireless channel, including both large and small scale fading phenomena as well as corresponding channel parameters and their impact on system performance....

Analysis Of Packets Delay In Wireless Data Networks

Directory of Open Access Journals (Sweden)

Krivchenkov Aleksandr

2015-12-01

Full Text Available The networks with wireless links for automation control applications traffic transmission when packets have small size and application payload is predictable are under consideration. Analytical model for packets delay on their propagation path through the network is proposed. Estimations for network architectures based on WiFi and Bluetooth wireless technologies are made. The specifications for physical layer 802.11 a/b/g/n and 802.15.1 are under consideration. Analytical and experimental results for delivered network bandwidth for different network architecture, traffic structure and wireless technologies were compared to validate that basic mechanisms are correctly taken into account in the model. It is shown that basic effects are taken into account and further accuracy “improvement” of the model will give not more than 5%. As a result that is important for automation control applications we have reliably received the lowest possible level for packets delay in one wireless link. For 802.11 it is of order of 0.2 ms, for 802.15.1 it is 1.25 ms and is true when application packet can be transferred by one data frame.

Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

DEFF Research Database (Denmark)

Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben

2010-01-01

A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital si...

Wireless Mobile Computing and its Links to Descriptive Complexity

Czech Academy of Sciences Publication Activity Database

Wiedermann, Jiří; Pardubská, D.

2008-01-01

Roč. 19, č. 4 (2008), s. 887-913 ISSN 0129-0541 R&D Projects: GA AV ČR 1ET100300517 Institutional research plan: CEZ:AV0Z10300504 Keywords : alternating Turing machine * simulation * simultaneous time-space complexity * wireless parallel Turing machine Subject RIV: IN - Informatics, Computer Science Impact factor: 0.554, year: 2008

An icon-based synoptic visualization of fully polarimetric radar data

OpenAIRE

Woodhouse, I.H.; Turner, Dean

2012-01-01

The visualization of fully polarimetric radar data is hindered by traditional remote sensing methodologies for displaying data due to the large number of parameters per pixel in such data, and the non-scalar nature of variables such as phase difference. In this paper, a new method is described that uses icons instead of image pixels to represent the image data so that polarimetric properties and geographic context can be visualized together. The icons are parameterized using the alpha-entropy...

Computer Icons and the Art of Memory.

Science.gov (United States)

McNair, John R.

1996-01-01

States that key aspects of "memoria," the ancient Art of Memory, especially its focus on vivid representational images set against distinct backgrounds, can be helpful in creating memorable, universal, and easily retrievable computer icons. (PA)

Wireless Neural Recording With Single Low-Power Integrated Circuit

Science.gov (United States)

Harrison, Reid R.; Kier, Ryan J.; Chestek, Cynthia A.; Gilja, Vikash; Nuyujukian, Paul; Ryu, Stephen; Greger, Bradley; Solzbacher, Florian; Shenoy, Krishna V.

2010-01-01

We present benchtop and in vivo experimental results from an integrated circuit designed for wireless implantable neural recording applications. The chip, which was fabricated in a commercially available 0.6-μm 2P3M BiCMOS process, contains 100 amplifiers, a 10-bit analog-to-digital converter (ADC), 100 threshold-based spike detectors, and a 902–928 MHz frequency-shift-keying (FSK) transmitter. Neural signals from a selected amplifier are sampled by the ADC at 15.7 kSps and telemetered over the FSK wireless data link. Power, clock, and command signals are sent to the chip wirelessly over a 2.765-MHz inductive (coil-to-coil) link. The chip is capable of operating with only two off-chip components: a power/command receiving coil and a 100-nF capacitor. PMID:19497825

BAROQUE AND ICONIC ECPHRASIS IN GOGOL'S "TARAS BULBA"

Directory of Open Access Journals (Sweden)

Anastasiya Viktorovna Kozlova

2015-01-01

Full Text Available This article discusses the tools verbalization European Baroque painting techniques and Old icons in the Gogol's story  "Taras Bulba". Narrative functions of implicit ecphrasis investigated in connection problem relatedness Catholicism and Orthodoxy in the minds of Gogol at the beginning of the 1840s.The purpose of the article analyzes the ways of verbalization and features of non-attributed implicit ecphrasis in the second edition of Gogol's "Taras Bulba" reproducing Caravaggio painting style and Old icons.Method or the methodology of work: Among research material are Gogol's "Taras Bulba" in two editions, the European Baroque paintings and ancient Russian icons. Were applied structural-typological, structural, intertextual, hermeneutical methods.Results: We describe the correlation of ecphrasis in Gogol with referents: the paintings of Caravaggio and Honthorst , and Old Russian iconography . Found that ecphrasis descriptions that appear only in the edition of 1842 are not local segments of the text and form the entire text layers, actively organizing narrative, operating plot and composition. Hidden emplisit ecphrasis is the artistic code, extending the semantic space of the text , the text translation tool of religious and philosophical ideas of the author. Valuable contraposition of baroque and iconic ecphrasis in the story reflects not only the author's reflection on the problem of beauty , inner and outer, but also a reflection of their own style.Application area: The results of our study can be used for lectures on the history of Russian literature of the XIX century, the history of Russian and European culture, cultural studies, specialized courses and electives in the problem of interaction between different kinds of art, as well as material for interdisciplinary humanities research, including in school practice teaching literature and art history.

Iconicity in the development of picture skills: typical development and implications for individuals with severe intellectual disabilities.

Science.gov (United States)

Stephenson, Jennifer

2009-01-01

The iconicity of graphic symbols and the iconicity hypothesis are theoretical concepts that have had an impact on the use of augmentative and alternative communication strategies for people with severe intellectual disabilities. This article reviews some of the recent literature on the impact of iconicity on symbol recognition and use by typically developing children and relates those findings to people with severe disability. It seems that although iconicity may have some impact on symbol learning, there are other variables that are likely to be much more important. It is likely that iconicity is not helpful to those learning graphic symbols who have little or no comprehension of spoken language.

On the Specification of Upward-Propagating Tides for ICON Science Investigations

Science.gov (United States)

Forbes, Jeffrey M.; Zhang, Xiaoli; Hagan, Maura E.; England, Scott L.; Liu, Guiping; Gasperini, Federico

2017-10-01

The National Center for Atmospheric Research (NCAR) Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) will provide a physics-based context for the interpretation of ICON measurements. To optimize the realism of the model simulations, ICON wind and temperature measurements near the ˜97 km lower boundary of the TIEGCM will be used to specify the upward-propagating tidal spectrum at this altitude. This will be done by fitting a set of basis functions called Hough Mode Extensions (HMEs) to 27-day mean tidal winds and temperatures between 90 and 105 km altitude and between 12 °S and 42 °N latitude on a day-by-day basis. The current paper assesses the veracity of the HME fitting methodology given the restricted latitude sampling and the UT-longitude sampling afforded by the MIGHTI instrument viewing from the ICON satellite, which will be in a circular 27° inclination orbit. These issues are investigated using the output from a reanalysis-driven global circulation model, which contains realistic variability of the important tidal components, as a mock data set. ICON sampling of the model reveals that the 27-day mean diurnal and semidiurnal tidal components replicate well the 27-day mean tidal components obtained from full synoptic sampling of the model, but the terdiurnal tidal components are not faithfully reproduced. It is also demonstrated that reconstructed tidal components based on HME fitting to the model tides between 12 °S and 42 °N latitude provide good approximations to the major tidal components expected to be encountered during the ICON mission. This is because the constraints provided by fitting both winds and temperatures over the 90-105 km height range are adequate to offset the restricted sampling in latitude. The boundary conditions provided by the methodology described herein will greatly enhance the ability of the TIEGCM to provide a physical framework for interpreting atmosphere-ionosphere coupling in ICON observations

Radio over fiber for wireless communications from fundamentals to advanced topics

CERN Document Server

Fernando, Xavier N

2014-01-01

A comprehensive evaluation of Fi-Wi,  enabling readers to design links using channel estimation and equalization algorithms  This book provides a detailed study of radio over fiber (ROF) based wireless communication systems, otherwise called fiber wireless (Fi-Wi) systems. This is an emerging hot topic where the abundant bandwidth of optical fiber is directly combined with the flexibility and mobility of wireless networks to provide broadband connectivity.  Its application is increasing because of the growing demand for broadband wireless services. In such a system the transmission of the ra

The Use of Iconic Words in Early Child-Parent Interactions

DEFF Research Database (Denmark)

Perlman, Marcus; Fusaroli, Riccardo; Fein, Deborah

2017-01-01

This paper examines the use of iconic words in early conversations between children and caregivers. The longitudinal data include a span of six observations of 35 children-parent dyads in the same semi-structured activity . Our findings show that children’s speech initially has a high proportion ...... are related to individual differences in the children’s cognitive skills. Our findings fit with the hypothesis that iconicity facilitates early word learning and may play an important role in learning to produce new words....

ICON: An artificial intelligence approach to radiologic differential diagnosis

International Nuclear Information System (INIS)

Swett, H.A.; Miller, P.L.

1986-01-01

ICON is a computer system, developed using artificial intelligence techniques, that is designed to help radiologists manage the large body of knowledge needed to perform differential diagnosis in radiology. The system's domain is lung disease in patients with lymphoproliferative disorders. The radiologist proposes a diagnostic hypothesis which he or she thinks explains the known clinical and chest radiographic findings. ICON responds with an English-language prose critique that discusses how and why the proposed diagnosis is or is not supported by the clinical literature and suggests further findings or clinical information that might make the diagnosis more secure

How to model wireless mesh networks topology

International Nuclear Information System (INIS)

Sanni, M L; Hashim, A A; Anwar, F; Ali, S; Ahmed, G S M

2013-01-01

The specification of network connectivity model or topology is the beginning of design and analysis in Computer Network researches. Wireless Mesh Networks is an autonomic network that is dynamically self-organised, self-configured while the mesh nodes establish automatic connectivity with the adjacent nodes in the relay network of wireless backbone routers. Researches in Wireless Mesh Networks range from node deployment to internetworking issues with sensor, Internet and cellular networks. These researches require modelling of relationships and interactions among nodes including technical characteristics of the links while satisfying the architectural requirements of the physical network. However, the existing topology generators model geographic topologies which constitute different architectures, thus may not be suitable in Wireless Mesh Networks scenarios. The existing methods of topology generation are explored, analysed and parameters for their characterisation are identified. Furthermore, an algorithm for the design of Wireless Mesh Networks topology based on square grid model is proposed in this paper. The performance of the topology generated is also evaluated. This research is particularly important in the generation of a close-to-real topology for ensuring relevance of design to the intended network and validity of results obtained in Wireless Mesh Networks researches

Understanding iconic texts from Spanish - literature course in pre - university

Directory of Open Access Journals (Sweden)

Marialina Ana García Escobio

2014-09-01

Full Text Available It is presented in this article the development of the skills to understand better, which is one of the essential objectives of the teaching of the mother tongue, that is why to understand the image as iconic sign requires taking its value as a system of meaning, but also to sustain their particular difference in front of the purely denotative structures, especially against the model of all semiotic: the linguistic sign in this process of understandin g is necessary to teach students to decode texts of different codes and place them in more complex communicative situations, that is why the present proposal is new; a way to understand iconic texts, from the teaching of Spanish and Literature in preuniver sity, so that the iconic communication is common for all subjects. It is also assumed the historical and cultural approach from Vigotsky and followers, and the developing didactics presented by Castellanos and others.

Design and implementation of a topology control scheme for wireless mesh networks

CSIR Research Space (South Africa)

Mudali, P

2009-09-01

Full Text Available The Wireless Mesh Network (WMN) backbone is usually comprised of stationary nodes but the transient nature of wireless links results in changing network topologies. Topology Control (TC) aims to preserve network connectivity in ad hoc and mesh...

Comparing Iconic Memory in Children with and without Attention Deficit Hyperactivity Disorder.

Science.gov (United States)

Ahmadi, Nastaran; Goodarzi, Mohammad Ali; Hadianfard, Habib; Mohamadi, Norolah; Farid, Daryush; Kholasehzadeh, Golrasteh; Sakhvidi, Mohammad Nadi; Hemyari, Camellia

2013-08-01

Children with attention deficit hyperactivity disorder (ADHD) do not process most information due to inattention and loss of the opportunity to save and retrieve information. Therefore, these children experience memory impairment. Although visual memory has been previously studied in children with ADHD, iconic memory in these children has been less evaluated. We aimed to study the possibility of iconic memory impairment in children with ADHD, and compare the results with that of children without ADHD. The experimental group of this study were 6-9 year-old children who referred to the Imam Hosein Clinic and were diagnosed as having ADHD by a psychiatrist during 2011-2012 (n = 30).The subjects were interviewed clinically by a psychologist; and in order to diagnose ADHD, their parents and teachers were asked to complete the child symptom inventory-4 (CSI-4). The comparison group were 6-9 year-old children without ADHD who studied in 1st and 2nd educational district of Yazd (n = 30). Subjects' iconic memory was assessed using an iconic memory task. Repeated measure ANOVA was used for data analysis. Based on the iconic memory test, the mean score of ADHD children was significantly lower than that of children without ADHD (P memory is weaker in children with ADHD, and they have weaker performance than normal children in both visual and auditory symbols at presentation durations of 50 and 100 ms. The performance of ADHD children improves as the stimulation time increases.

Wireless technologies for closed-loop retinal prostheses

Science.gov (United States)

Ng, David C.; Bai, Shun; Yang, Jiawei; Tran, Nhan; Skafidas, Efstratios

2009-12-01

In this paper, we discuss various technologies needed to develop retinal prostheses with wireless power and data telemetry operation. In addition to the need to communicate with the implanted device, supply of power to the retinal prosthesis is especially difficult. This is because, in the implanted state, the device is not fixed in position due to constant motion of the eye. Furthermore, a retinal prosthesis incorporating a high density electrode array of more than 1000 electrodes is expected to consume approximately 45 mW of power and require 300 kbps of image and stimulation data. The front end of the wireless power and data transmission, the antenna, needs to be small compared to the size of the eye. Also, the wireless module is expected to operate in the reactive near-field region due to small separation between the transmit and receive antennas compared to their size and corresponding operating wavelength. An inductive link is studied as a means to transfer power and for data telemetry between the implant and external unit. In this work, the use of integrated circuit and microfabrication technologies for implementing inductive links is discussed. A closed-loop approach is taken to improve performance and reach optimum operation condition. Design and simulation data are presented as the basis for development of viable wireless module prototypes.

Impact of wireless communication on multimedia application performance

Science.gov (United States)

Brown, Kevin A.

1999-01-01

Multimedia applications and specifically voice and video conferencing tools are widely used in business communications, and are quickly being discovered by the consumer market as well. At the same time, wireless communication services such as PCS voice and cellular data are becoming very popular, leading to the desire to deploy multimedia applications in the wireless environment. Wireless links, however, exhibit several characteristics which are different from traditional wired networks. These include: dynamically changing bandwidth due to mobile host movement in and out of cell where bandwidth is shared, high rates of packet corruption and subsequent loss, and frequent are lengthy disconnections due to obstacles, fading, and movement between cells. In addition, these effects are short-lived and difficult to reproduce, leading to a lack of adequate testing and analysis for applications used in wireless environments.

Network Coding Opportunities for Wireless Grids Formed by Mobile Devices

DEFF Research Database (Denmark)

Nielsen, Karsten Fyhn; Madsen, Tatiana Kozlova; Fitzek, Frank

2008-01-01

Wireless grids have potential in sharing communication, computational and storage resources making these networks more powerful, more robust, and less cost intensive. However, to enjoy the benefits of cooperative resource sharing, a number of issues should be addressed and the cost of the wireless...... link should be taken into account. We focus on the question how nodes can efficiently communicate and distribute data in a wireless grid. We show the potential of a network coding approach when nodes have the possibility to combine packets thus increasing the amount of information per transmission. Our...... implementation demonstrates the feasibility of network coding for wireless grids formed by mobile devices....

Voice over IP in Wireless Heterogeneous Networks

DEFF Research Database (Denmark)

Fathi, Hanane; Chakraborty, Shyam; Prasad, Ramjee

with the deployment of wireless heterogeneous systems, both speech and data traffic are carrried over wireless links by the same IP-based packet-switched infrastructure. However, this combination faces some challenges due to the inherent properties of the wireless network. The requirements for good quality VoIP...... communications are difficult to achieve in a time-varying environment due to channel errors and traffic congestion and across different systems. The provision of VoIP in wireless heterogeneous networks requires a set of time-efficient control mechanisms to support a VoIP session with acceptable quality....... The focus of Voice over IP in Wierless Heterogeneous Networks is on mechanisms that affect the VoIP user satisfaction  while not explicitly involved in the media session. This relates to the extra delays introduced by the security and the signaling protocols used to set up an authorized VoIP session...

Sport Concussion Management Using Facebook: A Feasibility Study of an Innovative Adjunct "iCon".

Science.gov (United States)

Ahmed, Osman Hassan; Schneiders, Anthony G; McCrory, Paul R; Sullivan, S John

2017-04-01

  Sport concussion is currently the focus of much international attention. Innovative methods to assist athletic trainers in facilitating management after this injury need to be investigated.   To investigate the feasibility of using a Facebook concussion-management program termed iCon (interactive concussion management) to facilitate the safe return to play (RTP) of young persons after sport concussion.   Observational study.   Facebook group containing interactive elements, with moderation and support from trained health care professionals.   Eleven participants (n = 9 men, n = 2 women; range, 18 to 28 years old) completed the study.   The study was conducted over a 3-month period, with participant questionnaires administered preintervention and postintervention. The primary focus was on the qualitative experiences of the participants and the effect of iCon on their RTP. Usage data were also collected.   At the completion of the study, all participants (100%) stated that they would recommend an intervention such as iCon to others. Their supporting quotes all indicated that iCon has the potential to improve the management of concussion among this cohort. Most participants (n = 9, 82%) stated they were better informed with regard to their RTP due to participating in iCon.   This interactive adjunct to traditional concussion management was appreciated among this participant group, which indicates the feasibility of a future, larger study of iCon. Athletic trainers should consider the role that multimedia technologies may play in assisting with the management of sport concussion.

3D visualization of ultra-fine ICON climate simulation data

Science.gov (United States)

Röber, Niklas; Spickermann, Dela; Böttinger, Michael

2016-04-01

Advances in high performance computing and model development allow the simulation of finer and more detailed climate experiments. The new ICON model is based on an unstructured triangular grid and can be used for a wide range of applications, ranging from global coupled climate simulations down to very detailed and high resolution regional experiments. It consists of an atmospheric and an oceanic component and scales very well for high numbers of cores. This allows us to conduct very detailed climate experiments with ultra-fine resolutions. ICON is jointly developed in partnership with DKRZ by the Max Planck Institute for Meteorology and the German Weather Service. This presentation discusses our current workflow for analyzing and visualizing this high resolution data. The ICON model has been used for eddy resolving (developed specific plugins for the free available visualization software ParaView and Vapor, which allows us to read and handle that much data. Within ParaView, we can additionally compare prognostic variables with performance data side by side to investigate the performance and scalability of the model. With the simulation running in parallel on several hundred nodes, an equal load balance is imperative. In our presentation we show visualizations of high-resolution ICON oceanographic and HDCP2 atmospheric simulations that were created using ParaView and Vapor. Furthermore we discuss our current efforts to improve our visualization capabilities, thereby exploring the potential of regular in-situ visualization, as well as of in-situ compression / post visualization.

Power Control and Coding Formulation for State Estimation with Wireless Sensors

DEFF Research Database (Denmark)

Quevedo, Daniel; Østergaard, Jan; Ahlen, Anders

2014-01-01

efficient communication. In this paper, we examine the role of power control and coding for Kalman filtering over wireless correlated channels. Two estimation architectures are considered; initially, the sensors send their measurements directly to a single gateway (GW). Next, wireless relay nodes provide...... additional links. The GW decides on the coding scheme and the transmitter power levels of the wireless nodes. The decision process is carried out online and adapts to varying channel conditions to improve the tradeoff between state estimation accuracy and energy expenditure. In combination with predictive......Technological advances made wireless sensors cheap and reliable enough to be brought into industrial use. A major challenge arises from the fact that wireless channels introduce random packet dropouts. Power control and coding are key enabling technologies in wireless communications to ensure...

THz photonic wireless links with 16-QAM modulation in the 375-450 GHz band

DEFF Research Database (Denmark)

Jia, Shi; Yu, Xianbin; Hu, Hao

2016-01-01

forward error correction (HD-FEC) threshold of 3.8e-3 with 7% overhead. In addition, we also successfully demonstrate hybrid photonic wireless transmission of 40 Gbit/s 16-QAM signal at carrier frequencies of 400 GHz and 425 GHz over 30 km standard single mode fiber (SSMF) between the optical baseband...... signal transmitter and the THz wireless transmitter with negligible induced power penalty.......We propose and experimentally demonstrate THz photonic wireless communication systems with 16-QAM modulation in the 375-450 GHz band. The overall throughput reaches as high as 80 Gbit/s by exploiting four THz channels with 5 Gbaud 16-QAM baseband modulation per channel. We create a coherent optical...

Analysis of route availability in inter-working multi-hop wireless networks

CSIR Research Space (South Africa)

Salami, O

2009-07-01

Full Text Available In order to link a source-destination node pair in inter-working multi-hop wireless networks, links or routes must first be available. It is only after establishing the availability of links and routes between nodes that factors which affect...

Chemists’ knowledge object. Formulation, modification and abandonment of iconic model

Directory of Open Access Journals (Sweden)

Rómulo Gallego Badillo

2006-12-01

Full Text Available This article presents an analysis of different perspectives in regards to chemistry scientific statute. The category of scientific model was considered to characterize the proposal and development of technological-iconic model. It was necessary to have a look at the time in which the introduction of analogical and symbolic models was indispensable to modify the initial model. It also established the way in which the technological-iconic model can be a didactic foundation to lead secondary students towards Chemistry as one of the natural sciences.

Supporting Adaptation of Wireless Communication Protocols

International Nuclear Information System (INIS)

Dhomeja, L.D.; Soomro, I.A.; Malkani, Y.A.

2016-01-01

Pervasive devices such as mobile phones and PDAs (Personal Digital Assistants) come with different wireless communication capabilities, for example, WiFi (Wireless Fidelity), Bluetooth, IrDA (Infrared), etc. In order for pervasive devices to interact with each other, they need to have matching (alike) communication capabilities, otherwise such heterogeneous devices would not be able to interact with each other. In this paper we address this issue and propose a system that makes devices with heterogeneous wireless communication capabilities communicate with each other. The proposed system supports adaptation of wireless communication protocols through a proxy, which sits between a client and a server, and supports adaptation of wireless communication protocols. Its functionality involves intercepting a request made by a client with a different wireless communication capability (e.g. Bluetooth) from what the server has (e.g. WiFi), connecting to the server and then sending results back to the client. We have tested the system by implementing a messaging service application and running it on the system. The proxy supports all Bluetooth protocols, i.e. OBEX (Object Exchange), L2CAP (Logical Link Control and Adaptation Protocol), RFCOM (Radio Frequency Communication) and WiFi protocol and can run on (J2MW (Java 2 Micro Edition) enabled mobile phones which support both Bluetooth and WiFi capabilities. (author)

Design and Evaluation of 10-Gbps Inter-satellite Optical Wireless Communication Link for Improved Performance

Science.gov (United States)

Gupta, Amit; Nagpal, Shaina

2017-05-01

Inter-satellite optical wireless communication (IsOWC) systems can be chosen over existing microwave satellite systems for deploying in space in the future due to their high bandwidth, small size, light weight, low power and low cost. However, the IsOWC system suffers from various attenuations due to weather conditions, turbulence or scintillations which limit its performance and decreases its availability. So, in order to improve the performance, IsOWC system using directly modulated laser source is proposed in this work. The system is designed and evaluated to be suitable for high data rate transmissions up to 10 Gbps. The performance of the system is investigated in order to reduce the cost and complexity of link and improving the quality of information signal. Further the proposed IsOWC system is analysed using BER analyser, power meter and oscilloscope Visualizer.

Fast decay of iconic memory in observers with mild cognitive impairments

OpenAIRE

Lu, Zhong-Lin; Neuse, James; Madigan, Stephen; Dosher, Barbara Anne

2005-01-01

In a previous clinical report, unusually fast decay of iconic memory was obtained from a subject who later developed Alzheimer's disease. By using the partial-report paradigm, iconic memory (a form of visual sensory memory) in a group of observers with mild cognitive impairments (MCI) was characterized and compared with that of young college-age adults and older controls. Relatively long stimulus exposures were used for all three groups to ensure that older observers could perceive the stimul...

75 FR 5637 - Culturally Significant Objects Imported for Exhibition Determinations: “Architecture as Icon...

Science.gov (United States)

2010-02-03

... Determinations: ``Architecture as Icon: Perception and Representation of Architecture in Byzantine Art'' SUMMARY... objects to be included in the exhibition ``Architecture as Icon: Perception and Representation of Architecture in Byzantine Art,'' imported from abroad for temporary exhibition within the United States, are of...

Age-Related Changes in Preschoolers' Ability to Communicate Using Iconic Gestures in the Absence of Speech

Science.gov (United States)

Vasc, Dermina; Miclea, Mircea

2018-01-01

Iconic gestures illustrate complex meanings and clarify and enrich the speech they accompany. Little is known, however, about how children use iconic gestures in the absence of speech. In this study, we used a cross-sectional design to investigate how 3-, 4- and 5-year-old children (N = 51) communicate using pantomime iconic gestures. Children…

L’ICÔNE : L’IMAGE ET L’INVISIBLE (Icon: The Image and the Invisible

Directory of Open Access Journals (Sweden)

Veronica Cibotaru

2015-06-01

Full Text Available An icon is part of the visible world, moreover, of things that are visible in a second degree. It is not only a sensitive thing, but a sensitive image of a sensitive entity. As an eikon, it is located in a platonic sense among the lowest degree of the doxa, and within the lowest degree of the scale of being. However it is not a simple sensitive and illusory representation of God, such as one criticized from a Kantian point of view. The profound sense of an icon lies in its opening towards the invisible. An icon tries to capture the invisible. How is this meeting point of the visible and the invisible entangled? Can an icon really allow us to “see” the invisible or is it only a profanation of the invisible? It is my aim to analyze those questions in the following article.

The iconic memory skills of brain injury survivors and non-brain injured controls after visual scanning training.

Science.gov (United States)

McClure, J T; Browning, R T; Vantrease, C M; Bittle, S T

1994-01-01

Previous research suggests that traumatic brain injury (TBI) results in impairment of iconic memory abilities.We would like to acknowledge the contribution of Jeffrey D. Vantrease, who wrote the software program for the Iconic Memory procedure and measurement. This raises serious implications for brain injury rehabilitation. Most cognitive rehabilitation programs do not include iconic memory training. Instead it is common for cognitive rehabilitation programs to focus on attention and concentration skills, memory skills, and visual scanning skills.This study compared the iconic memory skills of brain-injury survivors and control subjects who all reached criterion levels of visual scanning skills. This involved previous training for the brain-injury survivors using popular visual scanning programs that allowed them to visually scan with response time and accuracy within normal limits. Control subjects required only minimal training to reach normal limits criteria. This comparison allows for the dissociation of visual scanning skills and iconic memory skills.The results are discussed in terms of their implications for cognitive rehabilitation and the relationship between visual scanning training and iconic memory skills.

Analysis and Testing of Mobile Wireless Networks

Science.gov (United States)

Alena, Richard; Evenson, Darin; Rundquist, Victor; Clancy, Daniel (Technical Monitor)

2002-01-01

Wireless networks are being used to connect mobile computing elements in more applications as the technology matures. There are now many products (such as 802.11 and 802.11b) which ran in the ISM frequency band and comply with wireless network standards. They are being used increasingly to link mobile Intranet into Wired networks. Standard methods of analyzing and testing their performance and compatibility are needed to determine the limits of the technology. This paper presents analytical and experimental methods of determining network throughput, range and coverage, and interference sources. Both radio frequency (BE) domain and network domain analysis have been applied to determine wireless network throughput and range in the outdoor environment- Comparison of field test data taken under optimal conditions, with performance predicted from RF analysis, yielded quantitative results applicable to future designs. Layering multiple wireless network- sooners can increase performance. Wireless network components can be set to different radio frequency-hopping sequences or spreading functions, allowing more than one sooner to coexist. Therefore, we ran multiple 802.11-compliant systems concurrently in the same geographical area to determine interference effects and scalability, The results can be used to design of more robust networks which have multiple layers of wireless data communication paths and provide increased throughput overall.

An Interference-Aware Traffic-Priority-Based Link Scheduling Algorithm for Interference Mitigation in Multiple Wireless Body Area Networks

Directory of Open Access Journals (Sweden)

Thien T. T. Le

2016-12-01

Full Text Available Currently, wireless body area networks (WBANs are effectively used for health monitoring services. However, in cases where WBANs are densely deployed, interference among WBANs can cause serious degradation of network performance and reliability. Inter-WBAN interference can be reduced by scheduling the communication links of interfering WBANs. In this paper, we propose an interference-aware traffic-priority-based link scheduling (ITLS algorithm to overcome inter-WBAN interference in densely deployed WBANs. First, we model a network with multiple WBANs as an interference graph where node-level interference and traffic priority are taken into account. Second, we formulate link scheduling for multiple WBANs as an optimization model where the objective is to maximize the throughput of the entire network while ensuring the traffic priority of sensor nodes. Finally, we propose the ITLS algorithm for multiple WBANs on the basis of the optimization model. High spatial reuse is also achieved in the proposed ITLS algorithm. The proposed ITLS achieves high spatial reuse while considering traffic priority, packet length, and the number of interfered sensor nodes. Our simulation results show that the proposed ITLS significantly increases spatial reuse and network throughput with lower delay by mitigating inter-WBAN interference.

SIMO optical wireless links with nonzero boresight pointing errors over M modeled turbulence channels

Science.gov (United States)

Varotsos, G. K.; Nistazakis, H. E.; Petkovic, M. I.; Djordjevic, G. T.; Tombras, G. S.

2017-11-01

Over the last years terrestrial free-space optical (FSO) communication systems have demonstrated an increasing scientific and commercial interest in response to the growing demands for ultra high bandwidth, cost-effective and secure wireless data transmissions. However, due the signal propagation through the atmosphere, the performance of such links depends strongly on the atmospheric conditions such as weather phenomena and turbulence effect. Additionally, their operation is affected significantly by the pointing errors effect which is caused by the misalignment of the optical beam between the transmitter and the receiver. In order to address this significant performance degradation, several statistical models have been proposed, while particular attention has been also given to diversity methods. Here, the turbulence-induced fading of the received optical signal irradiance is studied through the M (alaga) distribution, which is an accurate model suitable for weak to strong turbulence conditions and unifies most of the well-known, previously emerged models. Thus, taking into account the atmospheric turbulence conditions along with the pointing errors effect with nonzero boresight and the modulation technique that is used, we derive mathematical expressions for the estimation of the average bit error rate performance for SIMO FSO links. Finally, proper numerical results are given to verify our derived expressions and Monte Carlo simulations are also provided to further validate the accuracy of the analysis proposed and the obtained mathematical expressions.

Photonics-assisted wireless link based on mm-wave reconfigurable antennas

DEFF Research Database (Denmark)

Feliciano daCosta, Igor; Cerqueira Sodré, Arismar; Rodriguez Páez, Juan Sebastián

2017-01-01

The authors report a novel concept for photonics-assisted and broadband optical-wireless indoor networks based on optically-controlled reconfigurable antenna arrays (OCRAAs) and photonic down conversion (PDC) techniques, operating in the 28 and 38 GHz frequency bands. The antenna bandwidth is opt...... for access networks in the mm-wave frequency range....

Battling Latency in Modern Wireless Networks

KAUST Repository

Showail, Ahmad

2018-05-15

Buffer sizing has a tremendous effect on the performance of Wi-Fi based networks. Choosing the right buffer size is challenging due to the dynamic nature of the wireless environment. Over buffering or ‘bufferbloat’ may produce unacceptable endto-end delays. On the other hand, small buffers may limit the performance gains that can be obtained with various IEEE 802.11n/ac enhancements, such as frame aggregation. We propose Wireless Queue Management (WQM), a novel, practical, and lightweight queue management scheme for wireless networks. WQM adapts the buffer size based on the wireless link characteristics and the network load. Furthermore, it accounts for aggregates length when deciding on the optimal buffer size. We evaluate WQM using our 10 nodes wireless testbed. WQM reduces the end-to-end delay by an order of magnitude compared to the default buffer size in Linux while achieving similar network throughput. Also, WQM outperforms state of the art bufferbloat solutions, namely CoDel and PIE. WQM achieves 7× less latency compared to PIE, and 2× compared to CoDel at the cost of 8% drop in goodput in the worst case. Further, WQM improves network fairness as it limits the ability of a single flow to saturate the buffers.

Battling Latency in Modern Wireless Networks

KAUST Repository

Showail, Ahmad; Shihada, Basem

2018-01-01

Buffer sizing has a tremendous effect on the performance of Wi-Fi based networks. Choosing the right buffer size is challenging due to the dynamic nature of the wireless environment. Over buffering or ‘bufferbloat’ may produce unacceptable endto-end delays. On the other hand, small buffers may limit the performance gains that can be obtained with various IEEE 802.11n/ac enhancements, such as frame aggregation. We propose Wireless Queue Management (WQM), a novel, practical, and lightweight queue management scheme for wireless networks. WQM adapts the buffer size based on the wireless link characteristics and the network load. Furthermore, it accounts for aggregates length when deciding on the optimal buffer size. We evaluate WQM using our 10 nodes wireless testbed. WQM reduces the end-to-end delay by an order of magnitude compared to the default buffer size in Linux while achieving similar network throughput. Also, WQM outperforms state of the art bufferbloat solutions, namely CoDel and PIE. WQM achieves 7× less latency compared to PIE, and 2× compared to CoDel at the cost of 8% drop in goodput in the worst case. Further, WQM improves network fairness as it limits the ability of a single flow to saturate the buffers.

Effects of eye contact and iconic gestures on message retention in human-robot interaction

NARCIS (Netherlands)

Dijk, van E.T.; Torta, E.; Cuijpers, R.H.

2013-01-01

The effects of iconic gestures and eye contact on message retention in human-robot interaction were investigated in a series of experiments. A humanoid robot gave short verbal messages to participants, accompanied either by iconic gestures or no gestures while making eye contact with the participant

Soldier-worn augmented reality system for tactical icon visualization

Science.gov (United States)

Roberts, David; Menozzi, Alberico; Clipp, Brian; Russler, Patrick; Cook, James; Karl, Robert; Wenger, Eric; Church, William; Mauger, Jennifer; Volpe, Chris; Argenta, Chris; Wille, Mark; Snarski, Stephen; Sherrill, Todd; Lupo, Jasper; Hobson, Ross; Frahm, Jan-Michael; Heinly, Jared

2012-06-01

This paper describes the development and demonstration of a soldier-worn augmented reality system testbed that provides intuitive 'heads-up' visualization of tactically-relevant geo-registered icons. Our system combines a robust soldier pose estimation capability with a helmet mounted see-through display to accurately overlay geo-registered iconography (i.e., navigation waypoints, blue forces, aircraft) on the soldier's view of reality. Applied Research Associates (ARA), in partnership with BAE Systems and the University of North Carolina - Chapel Hill (UNC-CH), has developed this testbed system in Phase 2 of the DARPA ULTRA-Vis (Urban Leader Tactical, Response, Awareness, and Visualization) program. The ULTRA-Vis testbed system functions in unprepared outdoor environments and is robust to numerous magnetic disturbances. We achieve accurate and robust pose estimation through fusion of inertial, magnetic, GPS, and computer vision data acquired from helmet kit sensors. Icons are rendered on a high-brightness, 40°×30° field of view see-through display. The system incorporates an information management engine to convert CoT (Cursor-on-Target) external data feeds into mil-standard icons for visualization. The user interface provides intuitive information display to support soldier navigation and situational awareness of mission-critical tactical information.

Iconic and Immediate Memory in Elementary School Children.

Science.gov (United States)

Ewert, G. D.; Janzen, H. L.

1978-01-01

As age and grade increased, recall on all tasks increased; subjects in grades three to six were also seen to have a fully developed Iconic Memory, while only sixth graders had a functionally developed Immediate Memory. (KR)

Energy Aware Computing in Cooperative Wireless Networks

DEFF Research Database (Denmark)

Olsen, Anders Brødløs; Fitzek, Frank H. P.; Koch, Peter

2005-01-01

In this work the idea of cooperation is applied to wireless communication systems. It is generally accepted that energy consumption is a significant design constraint for mobile handheld systems. We propose a novel method of cooperative task computing by distributing tasks among terminals over...... the unreliable wireless link. Principles of multi–processor energy aware task scheduling are used exploiting performance scalable technologies such as Dynamic Voltage Scaling (DVS). We introduce a novel mechanism referred to as D2VS and here it is shown by means of simulation that savings of 40% can be achieved....

Ultra Secure High Reliability Wireless Radiation Monitor

International Nuclear Information System (INIS)

Cordaro, J.; Shull, D.; Farrar, M.; Reeves, G.

2011-01-01

Radiation monitoring in nuclear facilities is essential to safe operation of the equipment as well as protecting personnel. In specific, typical air monitoring of radioactive gases or particulate involves complex systems of valves, pumps, piping and electronics. The challenge is to measure a representative sample in areas that are radioactively contaminated. Running cables and piping to these locations is very expensive due to the containment requirements. Penetration into and out of an airborne or containment area is complex and costly. The process rooms are built with thick rebar-enforced concrete walls with glove box containment chambers inside. Figure 1 shows high temperature radiation resistance cabling entering the top of a typical glove box. In some case, the entire processing area must be contained in a 'hot cell' where the only access into the chamber is via manipulators. An example is shown in Figure 2. A short range wireless network provides an ideal communication link for transmitting the data from the radiation sensor to a 'clean area', or area absent of any radiation fields or radioactive contamination. Radiation monitoring systems that protect personnel and equipment must meet stringent codes and standards due to the consequences of failure. At first glance a wired system would seem more desirable. Concerns with wireless communication include latency, jamming, spoofing, man in the middle attacks, and hacking. The Department of Energy's Savannah River National Laboratory (SRNL) has developed a prototype wireless radiation air monitoring system that address many of the concerns with wireless and allows quick deployment in radiation and contamination areas. It is stand alone and only requires a standard 120 VAC, 60 Hz power source. It is designed to be mounted or portable. The wireless link uses a National Security Agency (NSA) Suite B compliant wireless network from Fortress Technologies that is considered robust enough to be used for classified data

ULTRA SECURE HIGH RELIABILITY WIRELESS RADIATION MONITOR

Energy Technology Data Exchange (ETDEWEB)

Cordaro, J.; Shull, D.; Farrar, M.; Reeves, G.

2011-08-03

Radiation monitoring in nuclear facilities is essential to safe operation of the equipment as well as protecting personnel. In specific, typical air monitoring of radioactive gases or particulate involves complex systems of valves, pumps, piping and electronics. The challenge is to measure a representative sample in areas that are radioactively contaminated. Running cables and piping to these locations is very expensive due to the containment requirements. Penetration into and out of an airborne or containment area is complex and costly. The process rooms are built with thick rebar-enforced concrete walls with glove box containment chambers inside. Figure 1 shows high temperature radiation resistance cabling entering the top of a typical glove box. In some case, the entire processing area must be contained in a 'hot cell' where the only access into the chamber is via manipulators. An example is shown in Figure 2. A short range wireless network provides an ideal communication link for transmitting the data from the radiation sensor to a 'clean area', or area absent of any radiation fields or radioactive contamination. Radiation monitoring systems that protect personnel and equipment must meet stringent codes and standards due to the consequences of failure. At first glance a wired system would seem more desirable. Concerns with wireless communication include latency, jamming, spoofing, man in the middle attacks, and hacking. The Department of Energy's Savannah River National Laboratory (SRNL) has developed a prototype wireless radiation air monitoring system that address many of the concerns with wireless and allows quick deployment in radiation and contamination areas. It is stand alone and only requires a standard 120 VAC, 60 Hz power source. It is designed to be mounted or portable. The wireless link uses a National Security Agency (NSA) Suite B compliant wireless network from Fortress Technologies that is considered robust enough to be

ICON, a current model preamplifier in CMOS technology for use with high rate particle detectors

International Nuclear Information System (INIS)

Anghinolfi, F.; Aspell, P.; Campbell, M.; Heijne, E.H.M.; Jarron, P.; Meddeler, G.; Santiard, J.C.

1993-01-01

The ICON current mode preamplifier is intended for use in experiments at high rate hadron colliders. The transient response and noise performance have been analyzed. One chip has been made using an ICON circuit with resistive feedback to produce a preamplifier with a peaking time of below 10 ns. This fast preamplifier has a gain of 870 mV/pC and a power dissipation of around 1 mW. Another chip was made which uses the ICON circuit as the front-end to a dual port analog memory. The noise measured is between 2,400 e - and 3,000 e - . An important characteristic of ICON is that it can tolerate a detector leakage current of 10 μA at the DC coupled input. Therefore, it is very suitable for silicon detector systems under severe radiation conditions

Whiteboard Icons to Support the Blood-Test Process in an Emergency Department

DEFF Research Database (Denmark)

Torkilsheyggi, Arnvør Martinsdottir á; Hertzum, Morten; From, Gustav

2013-01-01

The competent treatment of emergency department (ED) patients requires an effective and efficient process for handling laboratory tests such as blood tests. This study investigates how ED clinicians go about the process, from ordering blood tests to acknowledging their results and, specifically......, assesses the use of whiteboard icons to support this process. On the basis of observation and interviews we find that the blood-test process is intertwined with multiple other temporal patterns in ED work. The whiteboard icons, which indicate four temporally distinct steps in the blood-test process......, support the nurses in maintaining the flow of patients through the ED and the physicians in assessing test results at timeouts. The main results of this study are, however, that the blood-test process is temporally and collaboratively complex, that the whiteboard icons pass by most of this complexity...

Iconic site development and legitimating policies : The changing role of water in Dutch identity discourses

NARCIS (Netherlands)

Terlouw, Kees

2014-01-01

This paper focusses on the role of iconic sites in the legitimation of policies. Traditionally the legitimation of administrations is based on national communities. The undermining of these territorial communities, through globalisation and individualisation, make iconic sites more important to

Transport Schemes for Fiber-Wireless Technology: Transmission Performance and Energy Efficiency

Directory of Open Access Journals (Sweden)

Christina Lim

2014-04-01

Full Text Available Fiber-wireless technology has been actively researched as a potential candidate for next generation broadband wireless signal distribution. Despite the popularity, this hybrid scheme has many technical challenges that impede the uptake and commercial deployment. One of the inherent issues is the transport of the wireless signals over a predominantly digital optical network in today’s telecommunication infrastructure. Many different approaches have been introduced and demonstrated with digitized RF transport of the wireless signals being the most compatible with the existing optical fiber networks. In this paper, we review our work in the area of digitized RF transport to address the inherent issues related to analog transport in the fiber-wireless links and compare the transmission performance and energy efficiency with the other transport strategies.

Showcasing Colombia＇s Native Icons in Beijing

Institute of Scientific and Technical Information of China (English)

ZHANGJINGDE

2004-01-01

THE Object/Colombia Exhibition, the biggest ever held in China, went on display at the Beijing Jintai Art Museum in July of 2003. This exhibition structured as a journey across historic Colombia, featuring five uses of objects as icons: furniture, decorations, containers, clothes, and ritual and games relics, all grouped

Effect of Typeface on Iconic Storage Capacity.

Science.gov (United States)

Hoffman, Valerie

Various aspects of iconic memory have been studied in the past. Two tachistoscopic experiments were conducted to examine how legibility of a stimulus affects a subject's ability to recall brief visual presentation. The studies used letter arrays set in four different typefaces (Helvetica, Cooper Black Outline, Electronic, Old English). In the…

Network coding and evolutionary theory for performance enhancement in wireless cooperative clusters

DEFF Research Database (Denmark)

Militano, Leonardo; Fitzek, Frank; Iera, Antonio

2010-01-01

Cooperation over short-range wireless links among user devices, which download remote contents through cellular links, is a paradigm quickly gaining ground, given that it can answer several technological and design issues that next-generation wireless applications will raise. Among others, energy...... are investigated and an ad hoc conceived Genetic Algorithm (GA) designed. Either the service time (the time needed for all nodes to receive the complete file) or the energy consumption for the nodes is used as objective function, showing in both cases the fast convergence for the algorithm that makes it preferable...

Visualization of the NASA ICON mission in 3d

Science.gov (United States)

Mendez, R. A., Jr.; Immel, T. J.; Miller, N.

2016-12-01

The ICON Explorer mission (http://icon.ssl.berkeley.edu) will provide several data products for the atmosphere and ionosphere after its launch in 2017. This project will support the mission by investigating the capability of these tools for visualization of current and predicted observatory characteristics and data acquisition. Visualization of this mission can be accomplished using tools like Google Earth or CesiumJS, as well assistance from Java or Python. Ideally we will bring this visualization into the homes of people without the need of additional software. The path of launching a standalone website, building this environment, and a full toolkit will be discussed. Eventually, the initial work could lead to the addition of a downloadable visualization packages for mission demonstration or science visualization.

CCM-R: Secure Counter Synchronization for IoT Wireless Link

DEFF Research Database (Denmark)

Roy, Upal; Yin, Jiachen; Andersen, Birger

2016-01-01

In this paper we propose and evaluate a new version of the CCM mode of operation, CCM-R, which isan extended and alternate version of the original CBC-MAC with Counter Mode(CCM) that was created to address the problem of counter synchronization. While CCM is considered secure when used/implemente...... it suitable for low-power wireless IoT devices....

Fiber-wireless links supporting high-capacity W-band channels

DEFF Research Database (Denmark)

Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

2013-01-01

Seamless convergence of fiber-optic and the wireless networks is of great interest for enabling transparent delivery of broadband services to users in different locations, including both metropolitan and rural areas. Current demand of bandwidth by end-users, especially using mobile devices...... latest findings and experimental results on the W-band, specifically on its 81-86GHz sub-band. These include photonic generation of millimeter-wave carriers and transmission performance of broadband signals on different types of fibers and span lengths....

The Sensory Components of High-Capacity Iconic Memory and Visual Working Memory

OpenAIRE

Bradley, Claire; Pearson, Joel

2012-01-01

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more “high-level” alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their...

The sensory components of high-capacity iconic memory and visual working memory

OpenAIRE

Claire eBradley; Claire eBradley; Joel ePearson

2012-01-01

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more high-level alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their c...

The impact of iconic gestures on foreign language word learning and its neural substrate.

Science.gov (United States)

Macedonia, Manuela; Müller, Karsten; Friederici, Angela D

2011-06-01

Vocabulary acquisition represents a major challenge in foreign language learning. Research has demonstrated that gestures accompanying speech have an impact on memory for verbal information in the speakers' mother tongue and, as recently shown, also in foreign language learning. However, the neural basis of this effect remains unclear. In a within-subjects design, we compared learning of novel words coupled with iconic and meaningless gestures. Iconic gestures helped learners to significantly better retain the verbal material over time. After the training, participants' brain activity was registered by means of fMRI while performing a word recognition task. Brain activations to words learned with iconic and with meaningless gestures were contrasted. We found activity in the premotor cortices for words encoded with iconic gestures. In contrast, words encoded with meaningless gestures elicited a network associated with cognitive control. These findings suggest that memory performance for newly learned words is not driven by the motor component as such, but by the motor image that matches an underlying representation of the word's semantics. Copyright © 2010 Wiley-Liss, Inc.

Simultaneous Wireless Power Transfer and Data Communication Using Synchronous Pulse-Controlled Load Modulation.

Science.gov (United States)

Mao, Shitong; Wang, Hao; Zhu, Chunbo; Mao, Zhi-Hong; Sun, Mingui

2017-10-01

Wireless Power Transfer (WPT) and wireless data communication are both important problems of research with various applications, especially in medicine. However, these two problems are usually studied separately. In this work, we present a joint study of both problems. Most medical electronic devices, such as smart implants, must have both a power supply to allow continuous operation and a communication link to pass information. Traditionally, separate wireless channels for power transfer and communication are utilized, which complicate the system structure, increase power consumption and make device miniaturization difficult. A more effective approach is to use a single wireless link with both functions of delivering power and passing information. We present a design of such a wireless link in which power and data travel in opposite directions. In order to aggressively miniaturize the implant and reduce power consumption, we eliminate the traditional multi-bit Analog-to-Digital Converter (ADC), digital memory and data transmission circuits all together. Instead, we use a pulse stream, which is obtained from the original biological signal, by a sigma-delta converter and an edge detector, to alter the load properties of the WPT channel. The resulting WPT signal is synchronized with the load changes therefore requiring no memory elements to record inter-pulse intervals. We take advantage of the high sensitivity of the resonant WPT to the load change, and the system dynamic response is used to transfer each pulse. The transient time of the WPT system is analyzed using the coupling mode theory (CMT). Our experimental results show that the memoryless approach works well for both power delivery and data transmission, providing a new wireless platform for the design of future miniaturized medical implants.

Design and Optimization of Ultrasonic Wireless Power Transmission Links for Millimeter-Sized Biomedical Implants.

Science.gov (United States)

Meng, Miao; Kiani, Mehdi

2017-02-01

Ultrasound has been recently proposed as an alternative modality for efficient wireless power transmission (WPT) to biomedical implants with millimeter (mm) dimensions. This paper presents the theory and design methodology of ultrasonic WPT links that involve mm-sized receivers (Rx). For given load (R L ) and powering distance (d), the optimal geometries of transmitter (Tx) and Rx ultrasonic transducers, including their diameter and thickness, as well as the optimal operation frequency (f c ) are found through a recursive design procedure to maximize the power transmission efficiency (PTE). First, a range of realistic f c s is found based on the Rx thickness constrain. For a chosen f c within the range, the diameter and thickness of the Rx transducer are then swept together to maximize PTE. Then, the diameter and thickness of the Tx transducer are optimized to maximize PTE. Finally, this procedure is repeated for different f c s to find the optimal f c and its corresponding transducer geometries that maximize PTE. A design example of ultrasonic link has been presented and optimized for WPT to a 1 mm 3 implant, including a disk-shaped piezoelectric transducer on a silicon die. In simulations, a PTE of 2.11% at f c of 1.8 MHz was achieved for R L of 2.5 [Formula: see text] at [Formula: see text]. In order to validate our simulations, an ultrasonic link was optimized for a 1 mm 3 piezoelectric transducer mounted on a printed circuit board (PCB), which led to simulated and measured PTEs of 0.65% and 0.66% at f c of 1.1 MHz for R L of 2.5 [Formula: see text] at [Formula: see text], respectively.

The sensory components of high-capacity iconic memory and visual working memory.

Science.gov (United States)

Bradley, Claire; Pearson, Joel

2012-01-01

EARLY VISUAL MEMORY CAN BE SPLIT INTO TWO PRIMARY COMPONENTS: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more "high-level" alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of three different visual features (color, orientation and motion) across a range of durations from 0 to 6 s. We found that the amount of information stored in iconic memory is smaller for motion than for color or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ∼2 s. Further experiments showed that performance for the 10 items at 1 s was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory, and an effortful "lower-capacity" visual working memory.

The sensory components of high-capacity iconic memory and visual working memory

Directory of Open Access Journals (Sweden)

Claire eBradley

2012-09-01

Full Text Available Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more high-level alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of 3 different visual features (colour, orientation and motion across a range of durations from 0 to 6 seconds. We found that the amount of information stored in iconic memory is smaller for motion than for colour or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ~2 seconds. Further experiments showed that performance for the 10 items at 1 second was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory and an effortful ‘lower-capacity’ visual working memory.

A wireless sensor enabled by wireless power.

Science.gov (United States)

Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

2012-11-22

Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network.

Design of an Omnidirectional Multibeam Transmitter for High-Speed Indoor Wireless Communications

Directory of Open Access Journals (Sweden)

Tang Jaw-Luen

2010-01-01

Full Text Available For future high speed indoor wireless communication, diffuse wireless optical communications offer more robust optical links against shadowing than line-of-sight links. However, their performance may be degraded by multipath dispersion arising from surface reflections. We have developed a multipath diffusive propagation model capable of providing channel impulse responses data. It is aimed to design and simulate any multibeam transmitter under a variety of indoor environments. In this paper, a multi-beam transmitter system associated with hemisphere structure is proposed to fight against the diverse effects of multipath distortion albeit, at the cost of increased laser power and cost. Simulation results of multiple impulse responses showed that this type of multi-beam transmitter can significantly improve the performance of BER suitable for high bit rate application. We present the performance and simulation results for both line-of-sight and diffuse link configurations. We propose a design of power radiation pattern for a transmitter in achieving uniform and full coverage of power distributions for diffuse indoor optical wireless systems.

Resource management for multimedia services in high data rate wireless networks

CERN Document Server

Zhang, Ruonan; Pan, Jianping

2017-01-01

This brief offers a valuable resource on principles of quality-of-service (QoS) provisioning and the related link-layer resource management techniques for high data-rate wireless networks. The primary emphasis is on protocol modeling and analysis. It introduces media access control (MAC) protocols, standards of wireless local area networks (WLANs), wireless personal area networks (WPANs), and wireless body area networks (WBANs), discussing their key technologies, applications, and deployment scenarios. The main analytical approaches and models for performance analysis of the fundamental resource scheduling mechanisms, including the contention-based, reservation-based, and hybrid MAC, are presented. To help readers understand and evaluate system performance, the brief contains a range of simulation results. In addition, a thorough bibliography provides an additional tool. This brief is an essential resource for engineers, researchers, students, and users of wireless networks.

"I use it when I see it": The role of development and experience in Deaf and hearing children's understanding of iconic gesture.

Science.gov (United States)

Magid, Rachel W; Pyers, Jennie E

2017-05-01

Iconicity is prevalent in gesture and in sign languages, yet the degree to which children recognize and leverage iconicity for early language learning is unclear. In Experiment 1 of the current study, we presented sign-naïve 3-, 4- and 5-year-olds (n=87) with iconic shape gestures and no additional scaffolding to ask whether children can spontaneously map iconic gestures to their referents. Four- and five-year-olds, but not three-year-olds, recognized the referents of iconic shape gestures above chance. Experiment 2 asked whether preschoolers (n=93) show an advantage in fast-mapping iconic gestures compared to arbitrary ones. We found that iconicity played a significant role in supporting 4- and 5-year-olds' ability to learn new gestures presented in an explicit pedagogical context, and a lesser role in 3-year-olds' learning. Using similar tasks in Experiment 3, we found that Deaf preschoolers (n=41) exposed to American Sign Language showed a similar pattern of recognition and learning but starting at an earlier age, suggesting that learning a language with rich iconicity may lead to earlier use of iconicity. These results suggest that sensitivity to iconicity is shaped by experience, and while not fundamental to the earliest stages of language development, is a useful tool once children unlock these form-meaning relationships. Copyright © 2017 Elsevier B.V. All rights reserved.

Towards Controlling Latency in Wireless Networks

KAUST Repository

Bouacida, Nader

2017-04-24

Wireless networks are undergoing an unprecedented revolution in the last decade. With the explosion of delay-sensitive applications in the Internet (i.e., online gaming and VoIP), latency becomes a major issue for the development of wireless technology. Taking advantage of the significant decline in memory prices, industrialists equip the network devices with larger buffering capacities to improve the network throughput by limiting packets drops. Over-buffering results in increasing the time that packets spend in the queues and, thus, introducing more latency in networks. This phenomenon is known as “bufferbloat”. While throughput is the dominant performance metric, latency also has a huge impact on user experience not only for real-time applications but also for common applications like web browsing, which is sensitive to latencies in order of hundreds of milliseconds. Concerns have arisen about designing sophisticated queue management schemes to mitigate the effects of such phenomenon. My thesis research aims to solve bufferbloat problem in both traditional half-duplex and cutting-edge full-duplex wireless systems by reducing delay while maximizing wireless links utilization and fairness. Our work shed lights on buffer management algorithms behavior in wireless networks and their ability to reduce latency resulting from excessive queuing delays inside oversized static network buffers without a significant loss in other network metrics. First of all, we address the problem of buffer management in wireless full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD-MAC), an asynchronous media access control protocol designed for relay full-duplexing. Compared to the default case, our solution reduces the end-to-end delay by two orders of magnitude while achieving similar throughput in most of the cases. In the second part of this thesis

LinkMind: Link Optimization in Swarming Mobile Sensor Networks

DEFF Research Database (Denmark)

Ngo, Trung Dung

2012-01-01

of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link...... optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm...

Wireless access to a pharmaceutical database: A demonstrator for data driven Wireless Application Prorocol (WAP) applications in medical information processing

DEFF Research Database (Denmark)

Hansen, Michael Schacht; Dørup, Jens

2001-01-01

script for easy update of the database. Data were distributed in 35 interrelated tables. Each pharmaceutical brand name was given its own card with links to general information about the drug, active substances, contraindications etc. Access was available through 1) browsing therapeutic groups and 2......) searching for a brand name. The database interface was programmed in the server-side scripting language PHP3. RESULTS: A free, open source Wireless Application Protocol gateway to a pharmaceutical catalogue was established to allow dial-in access independent of commercial Wireless Application Protocol...... service providers. The application was tested on the Nokia 7110 and Ericsson R320s cellular phones. CONCLUSIONS: We have demonstrated that Wireless Application Protocol-based access to a dynamic clinical database can be established using open source freeware. The project opens perspectives for a further...

Single Channel 106 Gbit/s 16QAM Wireless Transmission in the 0.4 THz Band

DEFF Research Database (Denmark)

Pang, Xiaodan; Jia, Shi; Ozolins, Oskars

2017-01-01

We experimentally demonstrate a single channel 32-GBd 16QAM THz wireless link operating in the 0.4 THz band. Post-FEC net data rate of 106 Gbit/s is successfully achieved without any spatial/frequency multiplexing.......We experimentally demonstrate a single channel 32-GBd 16QAM THz wireless link operating in the 0.4 THz band. Post-FEC net data rate of 106 Gbit/s is successfully achieved without any spatial/frequency multiplexing....

VT Wireless Broadband Availability by Census Block - 06-2011

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VTBB201106 VT Broadband Availability Dataset represents wireline and wireless 'broadband service' availability in VT as of 6/30/2011. This...

VT Wireless Broadband Availability by Census Block - 06-2013

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VTBB201306 VT Broadband Availability Dataset represents wireline and wireless 'broadband service' availability in VT as of 6/30/2013. This...

VT Wireless Broadband Availability by Census Block - 12-2012

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VTBB201212 VT Broadband Availability Dataset represents wireline and wireless 'broadband service' availability in VT as of 12/31/2012. This...

VT Wireless Broadband Availability by Census Block - 06-2010

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VTBB201006 VT Broadband Availability Dataset represents wireline and wireless 'broadband service' availability in VT as of 6/30/2010. This...

VT Wireless Broadband Availability by Census Block - 12-2010

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VTBB201012 VT Broadband Availability Dataset represents wireline and wireless 'broadband service' availability in VT as of 12/31/2010. This...

VT Wireless Broadband Availability by Census Block - 12-2011

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The VTBB201112 VT Broadband Availability Dataset represents wireline and wireless 'broadband service' availability in VT as of 12/31/2011. This...

Optical wireless communication in data centers

Science.gov (United States)

Arnon, Shlomi

2018-01-01

In the last decade data centers have become a crucial element in modern human society. However, to keep pace with internet data rate growth, new technologies supporting data center should develop. Integration of optical wireless communication (OWC) in data centers is one of the proposed technologies as augmented technology to the fiber network. One implementation of the OWC technology is deployment of optical wireless transceiver on top of the existing cable/fiber network as extension to the top of rack (TOR) switch; in this way, a dynamic and flexible network is created. Optical wireless communication could reduce energy consumption, increase the data rate, reduce the communication latency, increase flexibility and scalability, and reduce maintenance time and cost, in comparison to extra fiber network deployment. In this paper we review up to date literature in the field, propose an implementation scheme of OWC network, discuss ways to reduce energy consumption by parallel link communication and report preliminary measurement result of university data center environment.

Wireless Heart Patients and the Quantified Self

DEFF Research Database (Denmark)

Grew, Julie Christina; Svendsen, Mette Nordahl

2017-01-01

Remote monitoring of implantable cardioverter defibrillator (ICD) patients links patients wirelessly to the clinic via a box in their bedroom. The box transmits data from the ICD to a remote database accessible to clinicians without patient involvement. Data travel across time and space; clinicia...

Cross-cultural adaptation and measurement properties testing of the Iconographical Falls Efficacy Scale (Icon-FES).

Science.gov (United States)

Franco, Marcia Rodrigues; Pinto, Rafael Zambelli; Delbaere, Kim; Eto, Bianca Yumie; Faria, Maíra Sgobbi; Aoyagi, Giovana Ayumi; Steffens, Daniel; Pastre, Carlos Marcelo

2018-02-14

The Iconographical Falls Efficacy Scale (Icon-FES) is an innovative tool to assess concern of falling that uses pictures as visual cues to provide more complete environmental contexts. Advantages of Icon-FES over previous scales include the addition of more demanding balance-related activities, ability to assess concern about falling in highly functioning older people, and its normal distribution. To perform a cross-cultural adaptation and to assess the measurement properties of the 30-item and 10-item Icon-FES in a community-dwelling Brazilian older population. The cross-cultural adaptation followed the recommendations of international guidelines. We evaluated the measurement properties (i.e. internal consistency, test-retest reproducibility, standard error of the measurement, minimal detectable change, construct validity, ceiling/floor effect, data distribution and discriminative validity), in 100 community-dwelling people aged ≥60 years. The 30-item and 10-item Icon-FES-Brazil showed good internal consistency (alpha and omega >0.70) and excellent intra-rater reproducibility (ICC 2,1 =0.96 and 0.93, respectively). According to the standard error of the measurement and minimal detectable change, the magnitude of change needed to exceed the measurement error and variability were 7.2 and 3.4 points for the 30-item and 10-item Icon-FES, respectively. We observed an excellent correlation between both versions of the Icon-FES and Falls Efficacy Scale - International (rho=0.83, pmeasurement properties to evaluate concern about falling among the community-dwelling older population. Copyright © 2018 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Simulation Of Wireless Networked Control System Using TRUETIME And MATLAB

Directory of Open Access Journals (Sweden)

Nyan Phyo Aung

2015-08-01

Full Text Available Wireless networked control systems WNCS are attracting an increasing research interests in the past decade. Wireless networked control system WNCS is composed of a group of distributed sensors and actuators that communicate through wireless link which achieves distributed sensing and executing tasks. This is particularly relevant for the areas of communication control and computing where successful design of WNCS brings about new challenges to the researchers. The primary motivation of this survey paper is to examine the design issues and to provide directions for successful simulation and implementation of WNCS. The paper also as well reviews some simulation tools for such systems.

An Icon-Based Synoptic Visualization of Fully Polarimetric Radar Data

Directory of Open Access Journals (Sweden)

Iain H. Woodhouse

2012-03-01

Full Text Available The visualization of fully polarimetric radar data is hindered by traditional remote sensing methodologies for displaying data due to the large number of parameters per pixel in such data, and the non-scalar nature of variables such as phase difference. In this paper, a new method is described that uses icons instead of image pixels to represent the image data so that polarimetric properties and geographic context can be visualized together. The icons are parameterized using the alpha-entropy decomposition of polarimetric data. The resulting image allows the following five variables to be displayed simultaneously: unpolarized power, alpha angle, polarimetric entropy, anisotropy and orientation angle. Examples are given for both airborne and laboratory-based imaging.

Design and implementation of the wireless high voltage control system

International Nuclear Information System (INIS)

Srivastava, Saurabh; Misra, A.; Pandey, H.K.; Thakur, S.K.; Pandit, V.S.

2011-01-01

In this paper we will describe the implementation of the wireless link for controlling and monitoring the serial data between control PC and the interface card (general DAQ card), by replacing existing RS232 based remote control system for controlling and monitoring High Voltage Power Supply (120kV/50mA). The enhancement in the reliability is achieved by replacing old RS232 based control system with wireless system by isolating ground loop. (author)

Location based Network Optimizations for Mobile Wireless Networks

DEFF Research Database (Denmark)

Nielsen, Jimmy Jessen

selection in Wi-Fi networks and predictive handover optimization in heterogeneous wireless networks. The investigations in this work have indicated that location based network optimizations are beneficial compared to typical link measurement based approaches. Especially the knowledge of geographical...

Iconic cuisines, marketing and place promotion

OpenAIRE

Everett, Sally

2015-01-01

This chapter looks at how food and drink narratives are utilised to promote and create place identities. By exploring the concepts of heritage branding and constructed historical narratives, it illustrates how iconic cuisines are being employed to promote place and attract consumers. It argues that the marketing process is more than utilising established aspects of heritage cuisines and historical truths, as it is often about creating narratives to meet the evolving needs of destinations and ...

40-Gb/s PDM-QPSK signal transmission over 160-m wireless distance at W-band.

Science.gov (United States)

Xiao, Jiangnan; Yu, Jianjun; Li, Xinying; Xu, Yuming; Zhang, Ziran; Chen, Long

2015-03-15

We experimentally demonstrate a W-band optical-wireless transmission system over 160-m wireless distance with a bit rate up to 40 Gb/s. The optical-wireless transmission system adopts optical polarization-division-multiplexing (PDM), multiple-input multiple-output (MIMO) reception and antenna polarization diversity. Using this system, we experimentally demonstrate the 2×2 MIMO wireless delivery of 20- and 40-Gb/s PDM quadrature-phase-shift-keying (PDM-QPSK) signals over 640- and 160-m wireless links, respectively. The bit-error ratios (BERs) of these transmission systems are both less than the forward-error-correction (FEC) threshold of 3.8×10-3.

Emulating Wired Backhaul with Wireless Network Coding

DEFF Research Database (Denmark)

Thomsen, Henning; De Carvalho, Elisabeth; Popovski, Petar

2014-01-01

In this paper we address the need for wireless network densification. We propose a solution wherein the wired backhaul employed in heterogeneous cellular networks is replaced with wireless links, while maintaining the rate requirements of the uplink and downlink traffic of each user. The first...... of the two-way protocol. The transmit power is set high enough to enable successive decoding at the small cell base station where the downlink data to the user is first decoded and its contribution removed from the received signal followed by the uplink data from the user. The decoding of the second layer......, the uplink traffic to the user, remains identical to the one performed in a wired system. In the broadcast phase, the decoding of the downlink traffic can also be guaranteed to remain identical. Hence, our solution claims an emulation of a wired backhaul with wireless network coding with same performance. We...

Cross-Layer Techniques for Adaptive Video Streaming over Wireless Networks

Directory of Open Access Journals (Sweden)

Yufeng Shan

2005-02-01

Full Text Available Real-time streaming media over wireless networks is a challenging proposition due to the characteristics of video data and wireless channels. In this paper, we propose a set of cross-layer techniques for adaptive real-time video streaming over wireless networks. The adaptation is done with respect to both channel and data. The proposed novel packetization scheme constructs the application layer packet in such a way that it is decomposed exactly into an integer number of equal-sized radio link protocol (RLP packets. FEC codes are applied within an application packet at the RLP packet level rather than across different application packets and thus reduce delay at the receiver. A priority-based ARQ, together with a scheduling algorithm, is applied at the application layer to retransmit only the corrupted RLP packets within an application layer packet. Our approach combines the flexibility and programmability of application layer adaptations, with low delay and bandwidth efficiency of link layer techniques. Socket-level simulations are presented to verify the effectiveness of our approach.

Information Theoretical Limits of Free-Space Optical Links

KAUST Repository

Ansari, Imran Shafique

2016-08-25

Generalized fading has been an imminent part and parcel of wireless communications. It not only characterizes the wireless channel appropriately but also allows its utilization for further performance analysis of various types of wireless communication systems. Under the umbrella of generalized fading channels, a unified ergodic capacity analysis of a free-space optical (FSO) link under both types of detection techniques (i.e., intensity modulation/direct detection (IM/DD) as well as heterodyne detection) over generalized atmospheric turbulence channels that account for generalized pointing errors is presented. Specifically, unified exact closed-form expressions for the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system are presented. Subsequently, capitalizing on these unified statistics, unified exact closed-form expressions for ergodic capacity performance metric of FSO link transmission systems is offered. Additionally, for scenarios wherein the exact closed-form solution is not possible to obtain, some asymptotic results are derived in the high SNR regime. All the presented results are verified via computer-based Monte-Carlo simulations.

Semiotics Of Shape Of Block Notation As Icon Of Planetary Orbit

Directory of Open Access Journals (Sweden)

Ketut Sumerjana

2017-05-01

Full Text Available Block notation has a specific shape; however, its existence and the function of its shape are not recognized and are made to be intangible by its function as a symbol of tapping sound. In general, the basic shape of the block notation looks like an ellipse and is similar to the planetary orbit. Therefore, this present study focuses on the ellipse-shaped block notation as the icon of the planetary orbit. The phenomenological qualitative method was employed to interpret the meaning of the basic shape of the block notation as the icon of planetary orbit. The data were collected through guided interview and library research. The data were analyzed using the semiotic process, meaning that in the first phase the text was analyzed based on the shape structure and in the second phase the text was heuristically analyzed. The result of the study shows that the ellipse-shaped block notation is the planetary orbit whose function changes from the manifest function into the latent one, resulting from the function as the tapping sound value. Keywords: form, notation, icon, orbit, planet

Adapting cognitive radio technology for low-power wireless personal area network devices

DEFF Research Database (Denmark)

Toftegaard, Thomas Skjødeberg; Rohde, John

2011-01-01

The application of wireless personal area network (WPAN) and simple point-to-point wireless communication devices has increased drastically both in private household and in our workspaces in general over the last decade. Combined with the fact that the total number of wireless devices...... and associated standards present in the wireless environment is experiencing an extreme growth, the frequency spectrum scarcity is exposed as a severe challenge. Setting up efficient and reliable wireless WPAN links can be challenging even today. This is especially true because of the intensive use...... discusses the challenges associated with the implementation of highly reliable low-power WPAN networks for the future and the adaption of Cognitive Radio technology as a potential solution. A brief status on the maturity of CR technology will be presented as an integral part of this discussion....

Comparing Iconic Memory in Children with and without Attention Deficit Hyperactivity Disorder

Directory of Open Access Journals (Sweden)

Nastaran Ahmadi

2013-09-01

Full Text Available Objective: Children with attention deficit hyperactivity disorder (ADHD do not process most information due to inattention and loss of the opportunity to save and retrieve information. Therefore, these children experience memory impairment. Although visual memory has been previously studied in children with ADHD, iconic memory in these children has been less evaluated. We aimed to study the possibility of iconic memory impairment in children with ADHD, and compare the results with that of children without ADHD.Methods: The experimental group of this study were 6-9 year-old children who referred to the Imam Hosein Clinic and were diagnosed as having ADHD by a psychiatrist during 2011-2012 (n=30.The subjects were interviewed clinically by a psychologist; and in order to diagnose ADHD, their parents and teachers were asked to complete the child symptom inventory-4 (CSI-4. The comparison group were 6-9 year-old children without ADHD who studied in 1st and 2nd educational district of Yazd (n=30. Subjects’ iconic memory was assessed using an iconic memory task. Repeated measure ANOVA was used for data analysis. Results:Based on the iconic memory test, the mean score of ADHD children was significantly lower than that of children without ADHD (P˂0.001. Moreover, the performance of the experimental group differed significantly when the duration of the presentation differed from 50 ms to 100 ms as compared to the control group (P˂0.001. The number of correct answers increased in the experimental group as the duration of presentation increased. However, children with ADHD scored less than children without ADHD at 50 ms as well as 100 ms. The means of ADHD children increased as the duration of the presentation increased from 50 ms to 100 ms to 300 ms (P<0.001.Conclusion:Visual memory is weaker in children with ADHD, and they have weaker performance than normal children in both visual and auditory symbols at presentation durations of 50 and 100 ms. The

Symbolic Understanding of Pictures in Low-Functioning Children with Autism: The Effects of Iconicity and Naming

Science.gov (United States)

Hartley, Calum; Allen, Melissa L.

2015-01-01

This research investigated whether symbolic understanding of pictures in low-functioning children with autism is mediated by iconicity and language. In Experiment 1, participants were taught novel words paired with unfamiliar pictures that varied in iconicity (black-and-white line drawings, greyscale photographs, colour line drawings, colour…

Expertise Reversal for Iconic Representations in Science Visualizations

Science.gov (United States)

Homer, Bruce D.; Plass, Jan L.

2010-01-01

The influence of prior knowledge and cognitive development on the effectiveness of iconic representations in science visualizations was examined. Middle and high school students (N = 186) were given narrated visualizations of two chemistry topics: Kinetic Molecular Theory (Day 1) and Ideal Gas Laws (Day 2). For half of the visualizations, iconic…

PDA-phone-based instant transmission of radiological images over a CDMA network by combining the PACS screen with a Bluetooth-interfaced local wireless link.

Science.gov (United States)

Kim, Dong Keun; Yoo, Sun K; Park, Jeong Jin; Kim, Sun Ho

2007-06-01

Remote teleconsultation by specialists is important for timely, correct, and specialized emergency surgical and medical decision making. In this paper, we designed a new personal digital assistant (PDA)-phone-based emergency teleradiology system by combining cellular communication with Bluetooth-interfaced local wireless links. The mobility and portability resulting from the use of PDAs and wireless communication can provide a more effective means of emergency teleconsultation without requiring the user to be limited to a fixed location. Moreover, it enables synchronized radiological image sharing between the attending physician in the emergency room and the remote specialist on picture archiving and communication system terminals without distorted image acquisition. To enable rapid and fine-quality radiological image transmission over a cellular network in a secure manner, progressive compression and security mechanisms have been incorporated. The proposed system is tested over a code division Multiple Access 1x-Evolution Data-Only network to evaluate the performance and to demonstrate the feasibility of this system in a real-world setting.

Searching for Signs, Symbols, and Icons: Effects of Time of Day, Visual Complexity, and Grouping

Science.gov (United States)

McDougall, Sine; Tyrer, Victoria; Folkard, Simon

2006-01-01

Searching for icons, symbols, or signs is an integral part of tasks involving computer or radar displays, head-up displays in aircraft, or attending to road traffic signs. Icons therefore need to be designed to optimize search times, taking into account the factors likely to slow down visual search. Three factors likely to adversely affect visual…

Simplified Fiber-Wireless Distribution of HD Video in Passive and Active W-band Close Proximity Terminals

DEFF Research Database (Denmark)

Lebedev, Alexander; Rodes Lopez, Roberto; Yu, Xianbin

2012-01-01

We experimentally demonstrate uncompressed high-definition (HD) video distribution at 84 GHz Radio over Fiber link achieving up to 3 meters of wireless transmission. We experimentally emulate Metro-Access architecture by deploying single/multimode fibers. Passive and active approaches for remote...... antenna unit (RAU) are experimentally investigated. The bit error rate (BER) performance of the optical and wireless channels is reported. A successful transmission of uncompressed HD video in the W-band wireless channel is demonstrated with prospects to pave the way for application-focused fiber-wireless...

Wireless data transfer with mm-waves for future tracking detectors

International Nuclear Information System (INIS)

Pelikan, D.; Bingefors, N.; Brenner, R.; Gustafsson, L.; Dancila, D.

2014-01-01

Wireless data transfer has revolutionized the consumer market for the last decade generating many products equipped with transmitters and receivers for wireless data transfer. Wireless technology opens attractive possibilities for data transfer in future tracking detectors. The reduction of wires and connectors for data links is certainly beneficial both for the material budget and the reliability of the system. An advantage of wireless data transfer is the freedom of routing signals which today is particularly complicated when bringing the data the first 50 cm out of the tracker. With wireless links intelligence can be built into a tracker by introducing communication between tracking layers within a region of interest which would allow the construction of track primitives in real time. The wireless technology used in consumer products is however not suitable for tracker readouts. The low data transfer capacity of current 5 GHz transceivers and the relatively large feature sizes of the components is a disadvantage.Due to the requirement of high data rates in tracking detectors high bandwidth is required. The frequency band around 60 GHz turns out to be a very promising candidate for data transfer in a detector system. The high baseband frequency allows for data transfer in the order of several Gbit/s. Due to the small wavelength in the mm range only small structures are needed for the transmitting and receiving electronics. The 60 GHz frequency band is a strong candidate for future WLAN applications hence components are already starting to be available on the market.Patch antennas produced on flexible Printed Circuit Board substrate that can be used for wireless communication in future trackers are presented in this article. The antennas can be connected to transceivers for data transmission/reception or be connected by wave-guides to structures capable of bringing the 60 GHz signal behind boundaries. Results on simulation and fabrication of these antennas are

Wireless data transfer with mm-waves for future tracking detectors

Science.gov (United States)

Pelikan, D.; Bingefors, N.; Brenner, R.; Dancila, D.; Gustafsson, L.

2014-11-01

Wireless data transfer has revolutionized the consumer market for the last decade generating many products equipped with transmitters and receivers for wireless data transfer. Wireless technology opens attractive possibilities for data transfer in future tracking detectors. The reduction of wires and connectors for data links is certainly beneficial both for the material budget and the reliability of the system. An advantage of wireless data transfer is the freedom of routing signals which today is particularly complicated when bringing the data the first 50 cm out of the tracker. With wireless links intelligence can be built into a tracker by introducing communication between tracking layers within a region of interest which would allow the construction of track primitives in real time. The wireless technology used in consumer products is however not suitable for tracker readouts. The low data transfer capacity of current 5 GHz transceivers and the relatively large feature sizes of the components is a disadvantage.Due to the requirement of high data rates in tracking detectors high bandwidth is required. The frequency band around 60 GHz turns out to be a very promising candidate for data transfer in a detector system. The high baseband frequency allows for data transfer in the order of several Gbit/s. Due to the small wavelength in the mm range only small structures are needed for the transmitting and receiving electronics. The 60 GHz frequency band is a strong candidate for future WLAN applications hence components are already starting to be available on the market.Patch antennas produced on flexible Printed Circuit Board substrate that can be used for wireless communication in future trackers are presented in this article. The antennas can be connected to transceivers for data transmission/reception or be connected by wave-guides to structures capable of bringing the 60 GHz signal behind boundaries. Results on simulation and fabrication of these antennas are

Design and Implementation of Secure and Reliable Communication using Optical Wireless Communication

Science.gov (United States)

Saadi, Muhammad; Bajpai, Ambar; Zhao, Yan; Sangwongngam, Paramin; Wuttisittikulkij, Lunchakorn

2014-11-01

Wireless networking intensify the tractability in the home and office environment to connect the internet without wires but at the cost of risks associated with stealing the data or threat of loading malicious code with the intention of harming the network. In this paper, we proposed a novel method of establishing a secure and reliable communication link using optical wireless communication (OWC). For security, spatial diversity based transmission using two optical transmitters is used and the reliability in the link is achieved by a newly proposed method for the construction of structured parity check matrix for binary Low Density Parity Check (LDPC) codes. Experimental results show that a successful secure and reliable link between the transmitter and the receiver can be achieved by using the proposed novel technique.

Logo and semiosis: From an icon sign to the Serbian culture symbol

Directory of Open Access Journals (Sweden)

Bašić Ivana

2012-01-01

Full Text Available A logo is most commonly observed as an emblem with intent to be widely recognized as a permanent symbol, or an icon, additionally permitting correlative meanings within a designative context. In the particular example of the Glossary of Serbian culture logo the opportunities of elements of design (coded iconic message, non-coded iconic message and linguistic message have been analyzed with intention to ascertain communication with future users of the Index conveying the desired message not only about specificities of Serbian culture but also its complexity and unifying nature with the global culture. A logo is observed as a multi-parametric code transcending form a concept of artistic design to a “rhetoric figure” in context of presentation and promotion of Serbian culture. While the art of designing, as a discipline, has the objective of artistic modulation, as well as an aesthetic effect, it also, in this case, represents the form of the governmental strategy in communication with others and formation of the cultural identity of its citizens.

Novel method for water vapour monitoring using wireless communication networks measurements

Science.gov (United States)

David, N.; Alpert, P.; Messer, H.

2010-09-01

We propose a new technique for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from microwave links used in a backhaul cellular network that show very good correlation with surface station humidity measurements (comparisons were performed for several links, found at different locations, during different time periods, showing correlations in the range of 0.5-0.9).

Single- and Multiband OFDM Photonic Wireless Links in the 75−110 GHz Band Employing Optical Combs

DEFF Research Database (Denmark)

Beltrán, M.; Deng, Lei; Pang, Xiaodan

2012-01-01

, allowing the cost and energy efficiency of the system to be increased and supporting different users in the system. Four channels at 9.6 Gb/s/ch in 14.4-GHz bandwidth are generated and transmitted over up to 1.3-m wireless distance. The transmission of a 9.6-Gb/s single-channel signal occupying 3.2-GHz......The photonic generation of electrical orthogonal frequency-division multiplexing (OFDM) modulated wireless signals in the 75−110 GHz band is experimentally demonstrated employing in-phase/quadrature electrooptical modulation and optical heterodyn upconversion. The wireless transmission of 16......-quadrature-amplitude-modulation OFDM signals is demonstrated with a bit error rate performance within the forward error correction limits. Signals of 19.1 Gb/s in 6.3-GHz bandwidth are transmitted over up to 1.3-m wireless distance. Optical comb generation is further employed to support different channels...

Cultural Interpretations of the Visual Meaning of Icons and Images Used in North American Web Design

Science.gov (United States)

Knight, Eliot; Gunawardena, Charlotte N.; Aydin, Cengiz Hakan

2009-01-01

This study examines cross-cultural interpretations of icons and images drawn from US academic websites. Participants from Morocco, Sri Lanka, Turkey, and the USA responded to an online questionnaire containing 18 icons and images representing online functions and information types common on US academic websites. Participants supplied meanings for…

Wireless embedded control system for atomically precise manufacturing

KAUST Repository

Khan, Yasser; Randall, John N.

2011-01-01

This paper will explore the possibilities of implementing a wireless embedded control system for atomically precise manufacturing. The manufacturing process, similar to Scanning Tunneling Microscopy, takes place within an Ultra High Vacuum (UHV) chamber at a pressure of 10-10 torr. In order to create vibration isolation, and to keep internal noise to a minimum, a wireless link inside the UHV chamber becomes essential. We present a MATLAB simulation of the problem, and then demonstrate a hardware scheme between a Gumstix computer and a Linux based laptop for controlling nano-manipulators with three degrees of freedom. © 2011 IEEE.

Wireless embedded control system for atomically precise manufacturing

KAUST Repository

Khan, Yasser

2011-04-01

This paper will explore the possibilities of implementing a wireless embedded control system for atomically precise manufacturing. The manufacturing process, similar to Scanning Tunneling Microscopy, takes place within an Ultra High Vacuum (UHV) chamber at a pressure of 10-10 torr. In order to create vibration isolation, and to keep internal noise to a minimum, a wireless link inside the UHV chamber becomes essential. We present a MATLAB simulation of the problem, and then demonstrate a hardware scheme between a Gumstix computer and a Linux based laptop for controlling nano-manipulators with three degrees of freedom. © 2011 IEEE.

Cross Layer Interference Management in Wireless Biomedical Networks

Directory of Open Access Journals (Sweden)

Emmanouil G. Spanakis

2014-04-01

Full Text Available Interference, in wireless networks, is a central phenomenon when multiple uncoordinated links share a common communication medium. The study of the interference channel was initiated by Shannon in 1961 and since then this problem has been thoroughly elaborated at the Information theoretic level but its characterization still remains an open issue. When multiple uncoordinated links share a common medium the effect of interference is a crucial limiting factor for network performance. In this work, using cross layer cooperative communication techniques, we study how to compensate interference in the context of wireless biomedical networks, where many links transferring biomedical or other health related data may be formed and suffer from all other interfering transmissions, to allow successful receptions and improve the overall network performance. We define the interference limited communication range to be the critical communication region around a receiver, with a number of surrounding interfering nodes, within which a successful communication link can be formed. Our results indicate that we can achieve more successful transmissions by adapting the transmission rate and power, to the path loss exponent, and the selected mode of the underline communication technique allowing interference mitigation and when possible lower power consumption and increase achievable transmission rates.

Wireless sensor network performance metrics for building applications

Energy Technology Data Exchange (ETDEWEB)

Jang, W.S. (Department of Civil Engineering Yeungnam University 214-1 Dae-Dong, Gyeongsan-Si Gyeongsangbuk-Do 712-749 South Korea); Healy, W.M. [Building and Fire Research Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899-8632 (United States)

2010-06-15

Metrics are investigated to help assess the performance of wireless sensors in buildings. Wireless sensor networks present tremendous opportunities for energy savings and improvement in occupant comfort in buildings by making data about conditions and equipment more readily available. A key barrier to their adoption, however, is the uncertainty among users regarding the reliability of the wireless links through building construction. Tests were carried out that examined three performance metrics as a function of transmitter-receiver separation distance, transmitter power level, and obstruction type. These tests demonstrated, via the packet delivery rate, a clear transition from reliable to unreliable communications at different separation distances. While the packet delivery rate is difficult to measure in actual applications, the received signal strength indication correlated well with the drop in packet delivery rate in the relatively noise-free environment used in these tests. The concept of an equivalent distance was introduced to translate the range of reliability in open field operation to that seen in a typical building, thereby providing wireless system designers a rough estimate of the necessary spacing between sensor nodes in building applications. It is anticipated that the availability of straightforward metrics on the range of wireless sensors in buildings will enable more widespread sensing in buildings for improved control and fault detection. (author)

Terahertz communication: The opportunities of wireless technology beyond 5G

KAUST Repository

Elayan, Hadeel; Amin, Osama; Shubair, Raed M.; Alouini, Mohamed-Slim

2018-01-01

Over the past years, carrier frequencies used for wireless communications have been increasing to meet bandwidth requirements. The engineering community witnessed the development of wide radio bands such as the millimeter-wave (mmW) frequencies to fulfill the explosive growth of mobile data demand and pave the way towards 5G networks. Other research interests have been steered towards optical wireless communication to allow higher data rates, improve physical security and avoid electromagnetic interference. Nevertheless, a paradigm change in the electromagnetic wireless world has been witnessed with the exploitation of the Terahertz (THz) frequency band (0.1–10 THz). With the dawn of THz technology, which fills the gap between radio and optical frequency ranges, ultimate promise is expected for the next generation of wireless networks. In this paper, the light is shed on a number of opportunities associated with the deployment of the THz wireless links. These opportunities offer a plethora of applications to meet the future communication requirements and satisfy the ever increasing user demand of higher data rates.

Emulation Platform for Cyber Analysis of Wireless Communication Network Protocols

Energy Technology Data Exchange (ETDEWEB)

Van Leeuwen, Brian P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eldridge, John M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-11-01

Wireless networking and mobile communications is increasing around the world and in all sectors of our lives. With increasing use, the density and complexity of the systems increase with more base stations and advanced protocols to enable higher data throughputs. The security of data transported over wireless networks must also evolve with the advances in technologies enabling more capable wireless networks. However, means for analysis of the effectiveness of security approaches and implementations used on wireless networks are lacking. More specifically a capability to analyze the lower-layer protocols (i.e., Link and Physical layers) is a major challenge. An analysis approach that incorporates protocol implementations without the need for RF emissions is necessary. In this research paper several emulation tools and custom extensions that enable an analysis platform to perform cyber security analysis of lower layer wireless networks is presented. A use case of a published exploit in the 802.11 (i.e., WiFi) protocol family is provided to demonstrate the effectiveness of the described emulation platform.

Terahertz communication: The opportunities of wireless technology beyond 5G

KAUST Repository

Elayan, Hadeel

2018-05-17

Over the past years, carrier frequencies used for wireless communications have been increasing to meet bandwidth requirements. The engineering community witnessed the development of wide radio bands such as the millimeter-wave (mmW) frequencies to fulfill the explosive growth of mobile data demand and pave the way towards 5G networks. Other research interests have been steered towards optical wireless communication to allow higher data rates, improve physical security and avoid electromagnetic interference. Nevertheless, a paradigm change in the electromagnetic wireless world has been witnessed with the exploitation of the Terahertz (THz) frequency band (0.1–10 THz). With the dawn of THz technology, which fills the gap between radio and optical frequency ranges, ultimate promise is expected for the next generation of wireless networks. In this paper, the light is shed on a number of opportunities associated with the deployment of the THz wireless links. These opportunities offer a plethora of applications to meet the future communication requirements and satisfy the ever increasing user demand of higher data rates.

Fallingwater: Preserving an American icon

Directory of Open Access Journals (Sweden)

Lynda S. Waggoner

2000-12-01

Full Text Available Frank Lloyd Wright’s Fallingwater is an icon of 20th century architecture. It is undoubtedly one of the most emblematic, best known and most admired buildings in the world. The complex restoration process, which LOGGIA has the honour of including in this issue, has the added virtue that it throws new light on its design and execution. The restoration covers not only compromised structural and aesthetic aspects related to the concrete surfaces of the building but even the environmental management of the whole site, more and more endangered by the large number of visitors received.

Y. Laberge on Jazz Icons.

Directory of Open Access Journals (Sweden)

2010-05-01

Full Text Available (Various artists, Jazz Icons: Series 4. Reelin' In The Years Productions and Naxos, 2.108003. Box Set (8 DVDs, 2009, 10 hours. B&W. All regions (no DVD zone. 1. Coleman Hawkins- Live in '62 & '64- (w/ Sweets Edison and Jo Jones 2. Art Blakey- Live in '65- (w/ Freddie Hubbard 3.  Erroll Garner - Live in '63 & '64 4.  Jimmy Smith- Live in '69 5.  Woody Herman- Live in '64 6.  Anita O'Day- Live In '63 & '70 7.  Art Farmer- Live In '64- (w/ Jim Hall 8. Bonus performances, including excerpts...

Radio frequency identification enabled wireless sensing for intelligent food logistics.

Science.gov (United States)

Zou, Zhuo; Chen, Qiang; Chen, Qing; Uysal, Ismail; Zheng, Lirong

2014-06-13

Future technologies and applications for the Internet of Things (IoT) will evolve the process of the food supply chain and create added value of business. Radio frequency identifications (RFIDs) and wireless sensor networks (WSNs) have been considered as the key technological enablers. Intelligent tags, powered by autonomous energy, are attached on objects, networked by short-range wireless links, allowing the physical parameters such as temperatures and humidities as well as the location information to seamlessly integrate with the enterprise information system over the Internet. In this paper, challenges, considerations and design examples are reviewed from system, implementation and application perspectives, particularly with focus on intelligent packaging and logistics for the fresh food tracking and monitoring service. An IoT platform with a two-layer network architecture is introduced consisting of an asymmetric tag-reader link (RFID layer) and an ad-hoc link between readers (WSN layer), which are further connected to the Internet via cellular or Wi-Fi. Then, we provide insights into the enabling technology of RFID with sensing capabilities. Passive, semi-passive and active RFID solutions are discussed. In particular, we describe ultra-wideband radio RFID which has been considered as one of the most promising techniques for ultra-low-power and low-cost wireless sensing. Finally, an example is provided in the form of an application in fresh food tracking services and corresponding field testing results.

Nonlinear distortion in wireless systems modeling and simulation with Matlab

CERN Document Server

Gharaibeh, Khaled M

2011-01-01

This book covers the principles of modeling and simulation of nonlinear distortion in wireless communication systems with MATLAB simulations and techniques In this book, the author describes the principles of modeling and simulation of nonlinear distortion in single and multichannel wireless communication systems using both deterministic and stochastic signals. Models and simulation methods of nonlinear amplifiers explain in detail how to analyze and evaluate the performance of data communication links under nonlinear amplification. The book addresses the analysis of nonlinear systems

The dynamics of sensory buffers: geometric, spatial, and experience-dependent shaping of iconic memory.

Science.gov (United States)

Graziano, Martin; Sigman, Mariano

2008-05-23

When a stimulus is presented, its sensory trace decays rapidly, lasting for approximately 1000 ms. This brief and labile memory, referred as iconic memory, serves as a buffer before information is transferred to working memory and executive control. Here we explored the effect of different factors--geometric, spatial, and experience--with respect to the access and the maintenance of information in iconic memory and the progressive distortion of this memory. We studied performance in a partial report paradigm, a design wherein recall of only part of a stimulus array is required. Subjects had to report the identity of a letter in a location that was cued in a variable delay after the stimulus onset. Performance decayed exponentially with time, and we studied the different parameters (time constant, zero-delay value, and decay amplitude) as a function of the different factors. We observed that experience (determined by letter frequency) affected the access to iconic memory but not the temporal decay constant. On the contrary, spatial position affected the temporal course of delay. The entropy of the error distribution increased with time reflecting a progressive morphological distortion of the iconic buffer. We discuss our results on the context of a model of information access to executive control and how it is affected by learning and attention.

Wireless Infrared Networking in the Duke Paperless Classroom.

Science.gov (United States)

Stetten, George D.; Guthrie, Scott D.

1995-01-01

Discusses wireless (diffuse infrared) networking technology to link laptop computers in a computer programming and numerical methods course at Duke University (North Carolina). Describes products and technologies, and effects on classroom dynamics. Reports on effective instructional strategies for lecture, solving student problems, building shared…

Toward Wireless Health Monitoring via an Analog Signal Compression-Based Biosensing Platform.

Science.gov (United States)

Zhao, Xueyuan; Sadhu, Vidyasagar; Le, Tuan; Pompili, Dario; Javanmard, Mehdi

2018-06-01

Wireless all-analog biosensor design for the concurrent microfluidic and physiological signal monitoring is presented in this paper. The key component is an all-analog circuit capable of compressing two analog sources into one analog signal by the analog joint source-channel coding (AJSCC). Two circuit designs are discussed, including the stacked-voltage-controlled voltage source (VCVS) design with the fixed number of levels, and an improved design, which supports a flexible number of AJSCC levels. Experimental results are presented on the wireless biosensor prototype, composed of printed circuit board realizations of the stacked-VCVS design. Furthermore, circuit simulation and wireless link simulation results are presented on the improved design. Results indicate that the proposed wireless biosensor is well suited for sensing two biological signals simultaneously with high accuracy, and can be applied to a wide variety of low-power and low-cost wireless continuous health monitoring applications.

Strategic Control of 60 GHz Millimeter-Wave High-Speed Wireless Links for Distributed Virtual Reality Platforms

Directory of Open Access Journals (Sweden)

Joongheon Kim

2017-01-01

Full Text Available This paper discusses the stochastic and strategic control of 60 GHz millimeter-wave (mmWave wireless transmission for distributed and mobile virtual reality (VR applications. In VR scenarios, establishing wireless connection between VR data-center (called VR server (VRS and head-mounted VR device (called VRD allows various mobile services. Consequently, utilizing wireless technologies is obviously beneficial in VR applications. In order to transmit massive VR data, the 60 GHz mmWave wireless technology is considered in this research. However, transmitting the maximum amount of data introduces maximum power consumption in transceivers. Therefore, this paper proposes a dynamic/adaptive algorithm that can control the power allocation in the 60 GHz mmWave transceivers. The proposed algorithm dynamically controls the power allocation in order to achieve time-average energy-efficiency for VR data transmission over 60 GHz mmWave channels while preserving queue stabilization. The simulation results show that the proposed algorithm presents desired performance.

Up to 35 Gbps Ultra-Wideband Wireless Data Transmission Links

DEFF Research Database (Denmark)

Puerta Ramírez, Rafael; Rommel, Simon; Vegas Olmos, Juan José

2016-01-01

For the first time Ultra-Wideband record data transmission rates up to 35.1 Gbps and 21.6 Gbps are achieved, compliant with the restrictions on the effective radiated power established by both the United States Federal Communications Commission and the European Electronic Communications Committee......, respectively. To achieve these record bit rates, the multi-band approach of Carrierless Amplitude Phase modulation scheme was employed. Wireless transmissions were achieved with a BER below the 7% FEC threshold of 3.8·10-3 ....

Ultra-miniature wireless temperature sensor for thermal medicine applications.

Science.gov (United States)

Khairi, Ahmad; Hung, Shih-Chang; Paramesh, Jeyanandh; Fedder, Gary; Rabin, Yoed

2011-01-01

This study presents a prototype design of an ultra-miniature, wireless, battery-less, and implantable temperature-sensor, with applications to thermal medicine such as cryosurgery, hyperthermia, and thermal ablation. The design aims at a sensory device smaller than 1.5 mm in diameter and 3 mm in length, to enable minimally invasive deployment through a hypodermic needle. While the new device may be used for local temperature monitoring, simultaneous data collection from an array of such sensors can be used to reconstruct the 3D temperature field in the treated area, offering a unique capability in thermal medicine. The new sensory device consists of three major subsystems: a temperature-sensing core, a wireless data-communication unit, and a wireless power reception and management unit. Power is delivered wirelessly to the implant from an external source using an inductive link. To meet size requirements while enhancing reliability and minimizing cost, the implant is fully integrated in a regular foundry CMOS technology (0.15 μm in the current study), including the implant-side inductor of the power link. A temperature-sensing core that consists of a proportional-to-absolute-temperature (PTAT) circuit has been designed and characterized. It employs a microwatt chopper stabilized op-amp and dynamic element-matched current sources to achieve high absolute accuracy. A second order sigma-delta (Σ-Δ) analog-to-digital converter (ADC) is designed to convert the temperature reading to a digital code, which is transmitted by backscatter through the same antenna used for receiving power. A high-efficiency multi-stage differential CMOS rectifier has been designed to provide a DC supply to the sensing and communication subsystems. This paper focuses on the development of the all-CMOS temperature sensing core circuitry part of the device, and briefly reviews the wireless power delivery and communication subsystems.

STUDY OF SOME ARCHAEOMETRIC CHARACTERISTICS USED IN PANEL PAINTING ICONS AUTHENTICATION

Directory of Open Access Journals (Sweden)

Raluca Anamaria Cristache

2014-12-01

Full Text Available The authentication of cultural heritage assets is a complex process of scientific investigation which regards obtaining information about: author (painter, the period when it was made, the owners and other data related to the main contexts of their evolution in time (routes travelled. In fact, the identification of specific archaeometric features is aimed, in determining the materials composition and the patina, then the study of artistic techniques and technology used in the making process of a work of art. Latest serves to define the patrimonial elements and the role of the artifact in time. The expertise of old panel painting icons requires an interdisciplinary approach, correlating the artistic style with technique and materials used. In this regard, the specific techniques of microscopy and spectroscopy are very useful tools for determining the composition of structural elements and their deterioration / degradation state. This work presents a comparative study of the paper used in the preparation layer of three icons painted in Russian style. As an analysis techniques were used the micro and macro photography assisted by Optical Microscopy (OM, SEM-EDX and micro-FTIR. Based on the experimental data obtained, it was found that the icons belong to the first half of the 19th century.

Experimental Effects of Acute Exercise on Iconic Memory, Short-Term Episodic, and Long-Term Episodic Memory.

Science.gov (United States)

Yanes, Danielle; Loprinzi, Paul D

2018-06-11

The present experiment evaluated the effects of acute exercise on iconic memory and short- and long-term episodic memory. A two-arm, parallel-group randomized experiment was employed ( n = 20 per group; M age = 21 year). The experimental group engaged in an acute bout of moderate-intensity treadmill exercise for 15 min, while the control group engaged in a seated, time-matched computer task. Afterwards, the participants engaged in a paragraph-level episodic memory task (20 min delay and 24 h delay recall) as well as an iconic memory task, which involved 10 trials (at various speeds from 100 ms to 800 ms) of recalling letters from a 3 × 3 array matrix. For iconic memory, there was a significant main effect for time (F = 42.9, p memory scores at both the baseline (19.22 vs. 17.20) and follow-up (18.15 vs. 15.77), but these results were not statistically significant. These findings provide some suggestive evidence hinting towards an iconic memory and episodic benefit from acute exercise engagement.

Psychological peculiarities of icon perception during prayer through the lens of theological and literary texts in cultural-historical and christian context.

Directory of Open Access Journals (Sweden)

Helena DANILOV

2016-11-01

Full Text Available Psychological peculiarities of icon perception during prayer through the lens of theological and literary texts in cultural-historical and christian context. This research is dedicated to the psychotherapeutic effect of prayer in front of a Christian icon and icon mediated perception, namely the perception through the spectrum period of theological and modern literature (in Christian space, a registered historical decline known as "separation from church" time. In was identified and defined the concepts, as well as the functional pictogram and Christian prayer. For this purpose, it was investigated the theological texts and artistic works of local authors. In these texts the human being according to Christian conception, represent the symbol of a "living icon". These identify the main aim of pictogram as a mediator between human being and Higher Spirituality. The icon perception are "speculation in paints", which helps the person in building a dialogue between him and God, as the higher absolute spiritual and moral value. This research generates a main conclusion, where icon social perception of is an indicator of spiritual potential of human light.

A 30 Gb/s full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band.

Science.gov (United States)

Tang, Chanjuan; Yu, Jianjun; Li, Xinying; Chi, Nan; Xiao, Jiangnan; Tian, Yumin; Zhang, Junwen

2014-01-13

We propose and experimentally demonstrate a full-duplex bi-directional transmission optical wireless-over fiber integration system at W-band (75-100 GHz) with the speed up to 15 Gb/s for both 95.4 GHz link and 88.6 GHz link for the first time. The generation of millimeter-wave (mm-wave) wireless signal is based on the photonic technique by heterodyne mixing of an optical quadrature-phase-shift-keying (QPSK) signal with a free-running light at different wavelength. After 20 km fiber transmission, up to 30 Gb/s mm-wave signal is delivered over 2 m wireless link, and then converted to the optical signal for another 20 km fiber transmission. At the wireless receiver, coherent detection and advanced digital signal processing (DSP) are introduced to improve receiver sensitivity and system performance. With the OSNR of 15 dB, the bit error ratios (BERs) for 10 Gb/s signal transmission at 95.4 GHz and 88.6 GHz are below the forward-error-correction (FEC) threshold of 3.8 × 10(-3) whether post filter is used or not, while the BER for 15 Gb/s QPSK signal employing post filter in the link of 95.4 GHz is 2.9 × 10(-3).

Broadcast of four HD videos with LED ceiling lighting: optical-wireless MAC

Science.gov (United States)

Bouchet, Olivier; Porcon, Pascal; Gueutier, Eric

2011-09-01

The European project "hOME Gigabit Access Network" (OMEGA) targeted various wireless and wired solutions for 1 Gbit/s connectivity in Home Area Networks (HANs). One objective was to evaluate the suitability of optical wireless technologies in two spectral regions: visible light (visible-light communications - VLC) and near infrared (infrared communications - IRC). Several demonstrators have been built, all of them largely relying on overthe- shelf components. The demonstrators included a "wide-area" VLC broadcast link based on LED ceiling lighting and a laser-based high-data-rate "wide-area" IRC prototype. In this paper we discuss an adapted optical-wireless media-access-control (OWMAC) sublayer, which was developed and implemented during the project. It is suitable for both IRC and VLC. The VLC prototype is based on DMT signal processing and provides broadcasting at { 100 Mbit/s over an area of approximately 5 m2. The IRC prototype provides {300 Mbit/s half-duplex communication over an area of approximately 30 m2. The IRC mesh network, composed of one base station and two terminals, is based on OOK modulation, multi-sector transceivers, and an ultra-fast sector switch. After a brief discussion about the design of the optical-wireless data link layer and the optical-wireless switch (OWS) card, we address the card development and implementation. We also present applications for the VLC and IRC prototypes and measurement results regarding the MAC layer.

A full-duplex CATV/wireless-over-fiber lightwave transmission system.

Science.gov (United States)

Li, Chung-Yi; Lu, Hai-Han; Ying, Cheng-Ling; Cheng, Chun-Jen; Lin, Che-Yu; Wan, Zhi-Wei; Chen, Jian-Hua

2015-04-06

A full-duplex CATV/wireless-over-fiber lightwave transmission system consisting of one broadband light source (BLS), two optical interleavers (ILs), one intensity modulator, and one phase modulator is proposed and experimentally demonstrated. The downstream light is optically promoted from 10Gbps/25GHz microwave (MW) data signal to 10Gbps/100GHz and 10Gbps/50GHz millimeter-wave (MMW) data signals in fiber-wireless convergence, and intensity-modulated with 50-550 MHz CATV signal. For up-link transmission, the downstream light is phase-remodulated with 10Gbps/25GHz MW data signal in fiber-wireless convergence. Over a 40-km single-mode fiber (SMF) and a 10-m radio frequency (RF) wireless transport, bit error rate (BER), carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple-beat (CTB) are observed to perform well in such full-duplex CATV/wireless-over-fiber lightwave transmission systems. This full-duplex 100-GHz/50-GHz/25-GHz/550-MHz lightwave transmission system is an attractive alternative. This transmission system not only presents its advancement in the integration of fiber backbone and CATV/wireless feeder networks, but also it provides the advantages of a communication channel for higher data rates and bandwidth.

Crustal structure of an exhumed IntraCONtinental Sag (ICONS): the Mekele Basin in Northern Ethiopia.

Science.gov (United States)

Alemu, T. B.; Abdelsalam, M. G.

2017-12-01

The Mekele Sedimentary Basin (MSB) in Ethiopia is a Paleozoic-Mesozoic IntraCONtinental Sag (ICONS) exposed due to Cenozoic domal and rift flank uplift associated with the Afar mantle plume and Afar Depression (AD). ICONS are formed over stable lithosphere, and in contrast to rift and foreland basins, show circular-elliptical shape in map view, saucer shaped in cross section, and concentric gravity minima. Surface geological features of the MSB have been shown to exhibit geologic characteristics similar to those of other ICONS. We used the World Gravity Map (WGM 2012) data to investigate subsurface-crustal structure of the MSB. We also used 2D power spectrum analysis and inversion of the gravity field to estimate the Moho depth. Our results show the Bouguer anomalies of the WGM 2012 ranges between 130 mGal and - 110 mGal with the highest values within the AD. Despite the effect of the AD on the gravity anomalies, the MSB is characterized by the presence of gravity low anomaly that reaches in places -110 mGal, especially in its western part. The Moho depth estimates, from both spectral analysis and inversion of the gravity data, is between 36 and 40 km depth over most of the western and southern margins of the MSB. However, as the AD is approached, in the eastern margins of the MSB, crustal thickness estimates are highly affected by the anomalously thin and magmatic segment of the AD, and the Moho depth range between 30 and 25 km. Our results are consistent with that of seismic studies in areas far from the MSB, but within the Northwestern Ethiopian Plateau where the MSB is located. Those studies have reported an abrupt decrease in Moho depth from 40 km beneath the Northwestern plateau, to 20 km in the adjacent AD. Though the MSB is small (100 kmX100 km) compared to other ICONS, and affected by the neighboring AD, it is characterized by elliptical gravity minima and a relatively thicker crust that gradually thickens away from the rift. In addition, seismic imaging

An Analytical Study on an Orthodontic Index: Index of Complexity, Outcome and Need (ICON)

Science.gov (United States)

Torkan, Sepide; Pakshir, Hamid Reza; Fattahi, Hamid Reza; Oshagh, Morteza; Momeni Danaei, Shahla; Salehi, Parisa; Hedayati, Zohreh

2015-01-01

Statement of the Problem The validity of the Index of Complexity, Outcome and Need (ICON) which is an orthodontic index developed and introduced in 2000 should be studied in different ethnic groups. Purpose The aim of this study was to perform an analysis on the ICON and to verify whether this index is valid for assessing both the need and complexity of orthodontic treatment in Iran. Materials and Method Five orthodontists were asked to score pre-treatment diagnostic records of 100 patients with a uniform distribution of different types of malocclusions determined by Dental Health Component of the Index of Treatment Need. A calibrated examiner also assessed the need for orthodontic treatment and complexity of the cases based on the ICON index as well as the Index of Orthodontic Treatment Need (IOTN). 10 days later, 25% of the cases were re-scored by the panel of experts and the calibrated orthodontist. Results The weighted kappa revealed the inter-examiner reliability of the experts to be 0.63 and 0.51 for the need and complexity components, respectively. ROC curve was used to assess the validity of the index. A new cut-off point was adjusted at 35 in lieu of 43 as the suggested cut-off point. This cut-off point showed the highest level of sensitivity and specificity in our society for orthodontic treatment need (0.77 and 0.78, respectively), but it failed to define definite ranges for the complexity of treatment. Conclusion ICON is a valid index in assessing the need for treatment in Iran when the cut-off point is adjusted to 35. As for complexity of treatment, the index is not validated for our society. It seems that ICON is a well-suited substitute for the IOTN index. PMID:26331142

Wireless Augmented Reality Prototype (WARP)

Science.gov (United States)

Devereaux, A. S.

1999-01-01

Initiated in January, 1997, under NASA's Office of Life and Microgravity Sciences and Applications, the Wireless Augmented Reality Prototype (WARP) is a means to leverage recent advances in communications, displays, imaging sensors, biosensors, voice recognition and microelectronics to develop a hands-free, tetherless system capable of real-time personal display and control of computer system resources. Using WARP, an astronaut may efficiently operate and monitor any computer-controllable activity inside or outside the vehicle or station. The WARP concept is a lightweight, unobtrusive heads-up display with a wireless wearable control unit. Connectivity to the external system is achieved through a high-rate radio link from the WARP personal unit to a base station unit installed into any system PC. The radio link has been specially engineered to operate within the high- interference, high-multipath environment of a space shuttle or space station module. Through this virtual terminal, the astronaut will be able to view and manipulate imagery, text or video, using voice commands to control the terminal operations. WARP's hands-free access to computer-based instruction texts, diagrams and checklists replaces juggling manuals and clipboards, and tetherless computer system access allows free motion throughout a cabin while monitoring and operating equipment.

Effects of an icon-based menu labelling initiative on consumer food choice.

Science.gov (United States)

Kerins, Claire; Cunningham, Katie; Finucane, Francis M; Gibson, Irene; Jones, Jenni; Kelly, Colette

2017-01-01

The purpose of this study was to examine the impact of an icon-based menu labelling initiative on consumer buying behaviour. This quasi-experimental study recruited a convenience sample of eight food service establishments, all with at least one menu item meeting the heart healthy criteria. Data from sales of all menu items sold over an 8-week period were collated 4 weeks prior to and 4 weeks during the display of information icons related to healthy food choices on menus. The absolute change in menu item sales showed a non-significant trend towards an increase in healthier menu item selections. Furthermore, there was no association between the type of food service establishment and the percentage change in labelled menu item sales. The study did not find a statistically significant influence of the icon-based menu labels on consumer food choice. Given the limited amount of research that examines alternative menu labelling formats in real-world settings, more studies are necessary to confirm these results. Further research is needed to identify the optimal format, content and impact of menu labels on consumer behaviour.

Energy-efficient digital and wireless IC design for wireless smart sensing

Science.gov (United States)

Zhou, Jun; Huang, Xiongchuan; Wang, Chao; Tae-Hyoung Kim, Tony; Lian, Yong

2017-10-01

Wireless smart sensing is now widely used in various applications such as health monitoring and structural monitoring. In conventional wireless sensor nodes, significant power is consumed in wirelessly transmitting the raw data. Smart sensing adds local intelligence to the sensor node and reduces the amount of wireless data transmission via on-node digital signal processing. While the total power consumption is reduced compared to conventional wireless sensing, the power consumption of the digital processing becomes as dominant as wireless data transmission. This paper reviews the state-of-the-art energy-efficient digital and wireless IC design techniques for reducing the power consumption of the wireless smart sensor node to prolong battery life and enable self-powered applications.

Medium Access Control in Energy Harvesting - Wireless Sensor Networks

DEFF Research Database (Denmark)

Fafoutis, Xenofon

Focusing on Wireless Sensor Networks (WSN) that are powered by energy harvesting, this dissertation focuses on energy-efficient communication links between senders and receivers that are alternating between active and sleeping states of operation. In particular, the focus lies on Medium Access...

Objective aesthetic performance of Icon treatment by deep infiltration: a case report

Directory of Open Access Journals (Sweden)

Fabrizio Guerra

2016-06-01

Full Text Available Enamel hypomineralization is characterized by decreased refractive index of the lesion surface as compared to the surrounding sound enamel. Icon® treatment has been recently successfully used for the cosmetic treatment of enamel demineralizations seen in white spot lesions (WSLs and developmental defects of enamel (DDE. On the other hand, cases of molar incisal hypomineralization (MIH, deep lesions of traumatic origin, and those associated with severe fluorosis do not have the same response to this type of treatment. The application of a new deep Icon® infiltrative technique is proposed and the aesthetic results are validated by using a spectrophotometric approach as previously described by our group.

DEVELOPMENT OF WIRELESS TECHNIQUES IN DATA AND POWER TRANSMISSION APPLICATION FOR PARTICLE-PHYSICS DETECTORS

CERN Document Server

Brenner, R; Dehos, C; De Lurgio, P; Djurcic, Z; Drake, G; Gonzales Gimenez, JL; Gustafsson, L; Kim, DW; Locci, E; Pfeiffer, U; Röhrich, D; Rydberg, D; Schöning, A; Siligaris, A; Soltveit, HK; Ullaland, K; Vincent, P; Vasquez, PR; Wiedner, D; Yang, S

2017-01-01

In the WADAPT project described in this Letter of Intent, we propose to develop wireless techniques for data and power transmission in particle-physics detectors. Wireless techniques have developed extremely fast over the last decade and are now mature for being considered as a promising alternative to cables and optical links that would revolutionize the detector design. The WADAPT consortium has been formed to identify the specific needs of different projects that might benefit from wireless techniques with the objective of providing a common platform for research and development in order to optimize effectiveness and cost. The proposed R&D will aim at designing and testing wireless demonstrators for large instrumentation systems.

How early do children understand gesture-speech combinations with iconic gestures?

Science.gov (United States)

Stanfield, Carmen; Williamson, Rebecca; Ozçalişkan, Seyda

2014-03-01

Children understand gesture+speech combinations in which a deictic gesture adds new information to the accompanying speech by age 1;6 (Morford & Goldin-Meadow, 1992; 'push'+point at ball). This study explores how early children understand gesture+speech combinations in which an iconic gesture conveys additional information not found in the accompanying speech (e.g., 'read'+BOOK gesture). Our analysis of two- to four-year-old children's responses in a gesture+speech comprehension task showed that children grasp the meaning of iconic co-speech gestures by age three and continue to improve their understanding with age. Overall, our study highlights the important role gesture plays in language comprehension as children learn to unpack increasingly complex communications addressed to them at the early ages.

Terahertz wireless communication based on InP-related devices (Conference Presentation)

Science.gov (United States)

Lee, Eui Su; Kim, Hyun-Soo; Park, Jeong-Woo; Park, Dong Woo; Park, Kyung Hyun

2017-02-01

Recently, a wide interest has been gathered in using terahertz (THz) waves as the carrier waves for the next generation of broadband wireless communications. Upon this objective, the photonics technologies are very attractive for their usefulness in signal generations, modulations and detections with enhanced bandwidth and data rates, and the readiness in combining to the existing fiber-optic or wireless networks. In this paper, as a preliminary step toward the THz wireless communications, a THz wireless interconnection system with a broadband antenna-integrated uni-traveling-carrier photodiode (UTC-PD) and a Shottky-barrier diode (SBD) module will be presented. In our system, optical beating signals are generated and digitally modulated by the optical intensity modulator driven by a pulse pattern generator (PPG). As the receiver a SBD and an IF filter followed by a low-noise preamplifier and a limiting amplifier was used. With a 6-mA photocurrent of the UTC-PD which corresponds to the transmitter output power of about 30 μW at 280 GHz, an error-free (BERdefinition serial digital interface format was successfully transmitted over a wireless link.

Effects of Iconicity on Requesting with the Picture Exchange Communication System in Children with Autism Spectrum Disorder

Science.gov (United States)

Angermeier, Katie; Schlosser, Ralf W.; Luiselli, James K.; Harrington, Caroline; Carter, Beth

2008-01-01

Research on graphic symbol learning suggests that symbols with a greater visual resemblance to their referents (greater iconicity) are more easily learned. The iconicity hypothesis has not yet been explored within the intervention protocol of the Picture Exchange Communication System (PECS). Within the PECS protocol, participants do not point to a…

An Energy Efficient Adaptive Wireless Link for Farms based on IoT technologies

DEFF Research Database (Denmark)

Blaszczyk, tomasz; Lynggaard, Per

2016-01-01

There is a huge demand for automation infrastructures that increase the efficiency and the commercial potential for the agricultural sector. One approach to achieve these objectives is deploying Internet of Things including its embedded wireless sensor network platform. However, deploying wireles...

An Energy Efficient Adaptive Wireless Link for Farms based on IoT technologies

DEFF Research Database (Denmark)

Blaszczyk, Tomasz; Lynggaard, P.

2015-01-01

There is a huge demand for automation infrastructures that increase the efficiency and the commercial potential for the agricultural sector. One approach to achieve these objectives is deploying Internet of Things including its embedded wireless sensor network platform. However, deploying wireles...

Wireless device monitoring methods, wireless device monitoring systems, and articles of manufacture

Science.gov (United States)

McCown, Steven H [Rigby, ID; Derr, Kurt W [Idaho Falls, ID; Rohde, Kenneth W [Idaho Falls, ID

2012-05-08

Wireless device monitoring methods, wireless device monitoring systems, and articles of manufacture are described. According to one embodiment, a wireless device monitoring method includes accessing device configuration information of a wireless device present at a secure area, wherein the device configuration information comprises information regarding a configuration of the wireless device, accessing stored information corresponding to the wireless device, wherein the stored information comprises information regarding the configuration of the wireless device, comparing the device configuration information with the stored information, and indicating the wireless device as one of authorized and unauthorized for presence at the secure area using the comparing.

Iconic-Memory Processing of Unfamiliar Stimuli by Retarded and Nonretarded Individuals.

Science.gov (United States)

Hornstein, Henry A.; Mosley, James L.

1979-01-01

The iconic-memory processing of unfamiliar stimuli by 11 mentally retarded males (mean age 22 years) was undertaken employing a visually cued partial-report procedure and a visual masking procedure. (Author/CL)

"De-Randomizing" Congestion Losses to Improve TCP Performance over Wired-Wireless Networks

National Research Council Canada - National Science Library

Biaz, Saad; Vaidya, Nitin H

2004-01-01

.... With Internet becoming more heterogeneous with more and more wireless error-prone links, a TCP connection may unduly throttle its sending rate and experience poor performance over paths experiencing...

38-GHz millimeter wave beam steered fiber wireless systems for 5G indoor coverage: architectures, devices, and links

NARCIS (Netherlands)

Cao, Z.; Zhao, X.; Soares, F.M.; Tessema, N.M.; Koonen, A.M.J.

2017-01-01

Millimeter wave (mm-wave) beam steering is a key technique for the next generation (5G) wireless communication. The 28 and 38-GHz bands are widely considered as the candidates for 5G. In the context of indoor coverage, fiber-wireless systems with multiple simplified remote antenna sites are

Connecting icons, logos and slogans in graphic trademarks

OpenAIRE

Ambrožič, Maja

2016-01-01

In the public eye the organization is always considered or fully represented by its corporate identity that includes the size of the organization, annual payments, organizational structure, organizational culture, systems owned by the organization, premises, organizational culture, organizational strategy, mission, vision, number of employees etc. Graphic designer when designing graphic trademark by connecting graphic elements (logo, slogan and icon) must take in to consideration all abovemen...

Dynamics in small worlds of tree topologies of wireless sensor networks

DEFF Research Database (Denmark)

Li, Qiao; Zhang, Baihai; Fan, Zhun

2012-01-01

Tree topologies, which construct spatial graphs with large characteristic path lengths and small clustering coefficients, are ubiquitous in deployments of wireless sensor networks. Small worlds are investigated in tree-based networks. Due to link additions, characteristic path lengths reduce...... rapidly and clustering coefficients increase greatly. A tree abstract, Cayley tree, is considered for the study of the navigation algorithm, which runs automatically in the small worlds of tree-based networks. In the further study, epidemics in the small worlds of tree-based wireless sensor networks...

NASA Lunar Base Wireless System Propagation Analysis

Science.gov (United States)

Hwu, Shian U.; Upanavage, Matthew; Sham, Catherine C.

2007-01-01

results from this paper are important for the lunar wireless system link margin analysis in order to determine the limits on the reliable communication range, achievable data rate and RF coverage performance at planned lunar base work sites.

Prediction and comparison of down-link electric field and uplink localised SAR values for realistic indoor wireless planning

International Nuclear Information System (INIS)

Plets, David; Joseph, Wout; Aerts, Sam; Vanhecke, Kris; Vermeeren, Guenter; Martens, Luc

2014-01-01

In this paper, for the first time a heuristic network calculator for both whole-body exposure due to indoor base station antennas or access points (down-link exposure) and localised exposure due to the mobile device (uplink exposure) in indoor wireless networks is presented. As an application, three phone call scenarios are investigated (Universal Mobile Telecommunications System (UMTS) macro-cell, UMTS femto-cell and WiFi voice-over-IP) and compared with respect to the electric-field strength and localised specific absorption rate (SAR) distribution. Prediction models are created and successfully validated with an accuracy of 3 dB. The benefits of the UMTS power control mechanisms are demonstrated. However, dependent on the macro-cell connection quality and on the user's average phone call connection time, also the macro-cell solution might be preferential from an exposure point of view for the considered scenario. (authors)

Evaluation of coherence interference in optical wireless communication through multiscattering channels.

Science.gov (United States)

Kedar, Debbie; Arnon, Shlomi

2006-05-10

Optical wireless communication has been the subject of much research in recent years because of the increasing interest in laser satellite-ground links and urban optical wireless communication. The major sources of performance degradation have been identified as the spatial, angular, and temporal spread of the propagating beam when the propagation channel is multiscattering, resulting in reduced power reception and intersignal interference, as well as turbulence-induced scintillations and noise due to receiver circuitry and background illumination. However, coherence effects due to multipath interference caused by a scattering propagation channel do not appear to have been treated in detail in the scientific literature. We attempt a theoretical analysis of coherence interference in optical wireless communication through scattering channels and try to quantify the resultant performance degradation for different media. We conclude that coherence interference is discernible in optical wireless communication through scattering channels and is highly dependent on the microscopic nature of the propagation medium.

When expectation confounds iconic memory.

Science.gov (United States)

Bachmann, Talis; Aru, Jaan

2016-10-01

In response to the methodological criticism (Bachmann & Aru, 2015) of the interpretation of their earlier experimental results (Mack, Erol, & Clarke, 2015) Mack, Erol, Clarke, and Bert (2016) presented new results that they interpret again in favor of the stance that an attention-free phenomenal iconic store does not exist. Here we once more question their conclusions. When their subjects were unexpectedly asked to report the letters instead of the post-cued circles in the 101th trial where letters were actually absent, they likely failed to see the empty display area because prior experience with letters in the preceding trials produced expectancy based illusory experience of letter-like objects. Copyright © 2016 Elsevier Inc. All rights reserved.

the spirituality of andrei rublev's icon of the holy trinity

African Journals Online (AJOL)

supposed to read God in the icon's form, colours and figures. How does .... ture of deep blue and dark red in a combination which allows him to create the impression of .... on earth and under the earth, and that every tongue should confess that.

Wireless virtualization

CERN Document Server

Wen, Heming; Le-Ngoc, Tho

2013-01-01

This SpringerBriefs is an overview of the emerging field of wireless access and mobile network virtualization. It provides a clear and relevant picture of the current virtualization trends in wireless technologies by summarizing and comparing different architectures, techniques and technologies applicable to a future virtualized wireless network infrastructure. The readers are exposed to a short walkthrough of the future Internet initiative and network virtualization technologies in order to understand the potential role of wireless virtualization in the broader context of next-generation ubiq

Doubling transmission capacity in optical wireless system by antenna horizontal- and vertical-polarization multiplexing.

Science.gov (United States)

Li, Xinying; Yu, Jianjun; Zhang, Junwen; Dong, Ze; Chi, Nan

2013-06-15

We experimentally demonstrate 2×56 Gb/s two-channel polarization-division-multiplexing quadrature-phase-shift-keying signal delivery over 80 km single-mode fiber-28 and 2 m Q-band (33-50 GHz) wireless link, adopting antenna horizontal- (H-) and vertical-polarization (V-polarization) multiplexing. At the wireless receiver, classic constant-modulus-algorithm equalization based on digital signal processing can realize polarization demultiplexing and remove the crosstalk at the same antenna polarization. By adopting antenna polarization multiplexing, the signal baud rate and performance requirements for optical and wireless devices can be reduced but at the cost of double antennas and devices, while wireless transmission capacity can also be increased but at the cost of stricter requirements for V-polarization. The isolation is only about 19 dB when V-polarization deviation approaches 10°, which will affect high-speed (>50 Gb/s) wireless delivery.

OPS: Opportunistic pipeline scheduling in long-strip wireless sensor networks with unreliable links

NARCIS (Netherlands)

Guo, Peng; Meratnia, Nirvana; Havinga, Paul J.M.; Jiang, He; Zhang, Kui

2015-01-01

Being deployed in narrow but long area, strip wireless sensor networks (SWSNs) have drawn much attention in applications such as coal mines, pipeline and structure monitoring. One of typical characteristics of SWSNs is the large hop counts, which leads to long end-to-end delivery delay in

Wireless recording systems: from noninvasive EEG-NIRS to invasive EEG devices.

Science.gov (United States)

Sawan, Mohamad; Salam, Muhammad T; Le Lan, Jérôme; Kassab, Amal; Gelinas, Sébastien; Vannasing, Phetsamone; Lesage, Frédéric; Lassonde, Maryse; Nguyen, Dang K

2013-04-01

In this paper, we present the design and implementation of a wireless wearable electronic system dedicated to remote data recording for brain monitoring. The reported wireless recording system is used for a) simultaneous near-infrared spectrometry (NIRS) and scalp electro-encephalography (EEG) for noninvasive monitoring and b) intracerebral EEG (icEEG) for invasive monitoring. Bluetooth and dual radio links were introduced for these recordings. The Bluetooth-based device was embedded in a noninvasive multichannel EEG-NIRS system for easy portability and long-term monitoring. On the other hand, the 32-channel implantable recording device offers 24-bit resolution, tunable features, and a sampling frequency up to 2 kHz per channel. The analog front-end preamplifier presents low input-referred noise of 5 μ VRMS and a signal-to-noise ratio of 112 dB. The communication link is implemented using a dual-band radio frequency transceiver offering a half-duplex 800 kb/s data rate, 16.5 mW power consumption and less than 10(-10) post-correction Bit-Error Rate (BER). The designed system can be accessed and controlled by a computer with a user-friendly graphical interface. The proposed wireless implantable recording device was tested in vitro using real icEEG signals from two patients with refractory epilepsy. The wirelessly recorded signals were compared to the original signals recorded using wired-connection, and measured normalized root-mean square deviation was under 2%.

EMOTION DESIGN OF AN ICONIC (VOLKSWAGEN) CAMPERVAN

OpenAIRE

Kagali, Linus

2014-01-01

This research looks into the thinking and the process of re-design a piece of automotive icon, the Volkswagen campervan known as T1 or microbus. The campervan re-designed with new visual language, and emotions. The re-designed campervan is intended for the new generation of campers and outdoor seekers, a generation of tech savvy people in a world which is rapidly and gradually changing. The need of understanding the relationship between design and emotions fuelled this design project, bas...

Limits to the Usability of Iconic Memory

OpenAIRE

Ronald A. Rensink

2014-01-01

Human vision briefly retains a trace of a stimulus after it disappears. This trace—iconic memory—is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report) of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alterna...

Towards low-cost gigabit wireless systems at 60 GHz

NARCIS (Netherlands)

Yang, Haibing

2008-01-01

The world-wide availability of the huge amount of license-free spectral space in the 60 GHz band provides wide room for gigabit-per-second (Gb/s) wireless applications. A commercial (read: low-cost) 60-GHz transceiver will, however, provide limited system performance due to the stringent link budget

Algorithms for energy efficiency in wireless sensor networks

Energy Technology Data Exchange (ETDEWEB)

Busse, M

2007-01-21

The recent advances in microsensor and semiconductor technology have opened a new field within computer science: the networking of small-sized sensors which are capable of sensing, processing, and communicating. Such wireless sensor networks offer new applications in the areas of habitat and environment monitoring, disaster control and operation, military and intelligence control, object tracking, video surveillance, traffic control, as well as in health care and home automation. It is likely that the deployed sensors will be battery-powered, which will limit the energy capacity significantly. Thus, energy efficiency becomes one of the main challenges that need to be taken into account, and the design of energy-efficient algorithms is a major contribution of this thesis. As the wireless communication in the network is one of the main energy consumers, we first consider in detail the characteristics of wireless communication. By using the embedded sensor board (ESB) platform recently developed by the Free University of Berlin, we analyze the means of forward error correction and propose an appropriate resync mechanism, which improves the communication between two ESB nodes substantially. Afterwards, we focus on the forwarding of data packets through the network. We present the algorithms energy-efficient forwarding (EEF), lifetime-efficient forwarding (LEF), and energy-efficient aggregation forwarding (EEAF). While EEF is designed to maximize the number of data bytes delivered per energy unit, LEF additionally takes into account the residual energy of forwarding nodes. In so doing, LEF further prolongs the lifetime of the network. Energy savings due to data aggregation and in-network processing are exploited by EEAF. Besides single-link forwarding, in which data packets are sent to only one forwarding node, we also study the impact of multi-link forwarding, which exploits the broadcast characteristics of the wireless medium by sending packets to several (potential

Algorithms for energy efficiency in wireless sensor networks

Energy Technology Data Exchange (ETDEWEB)

Busse, M.

2007-01-21

The recent advances in microsensor and semiconductor technology have opened a new field within computer science: the networking of small-sized sensors which are capable of sensing, processing, and communicating. Such wireless sensor networks offer new applications in the areas of habitat and environment monitoring, disaster control and operation, military and intelligence control, object tracking, video surveillance, traffic control, as well as in health care and home automation. It is likely that the deployed sensors will be battery-powered, which will limit the energy capacity significantly. Thus, energy efficiency becomes one of the main challenges that need to be taken into account, and the design of energy-efficient algorithms is a major contribution of this thesis. As the wireless communication in the network is one of the main energy consumers, we first consider in detail the characteristics of wireless communication. By using the embedded sensor board (ESB) platform recently developed by the Free University of Berlin, we analyze the means of forward error correction and propose an appropriate resync mechanism, which improves the communication between two ESB nodes substantially. Afterwards, we focus on the forwarding of data packets through the network. We present the algorithms energy-efficient forwarding (EEF), lifetime-efficient forwarding (LEF), and energy-efficient aggregation forwarding (EEAF). While EEF is designed to maximize the number of data bytes delivered per energy unit, LEF additionally takes into account the residual energy of forwarding nodes. In so doing, LEF further prolongs the lifetime of the network. Energy savings due to data aggregation and in-network processing are exploited by EEAF. Besides single-link forwarding, in which data packets are sent to only one forwarding node, we also study the impact of multi-link forwarding, which exploits the broadcast characteristics of the wireless medium by sending packets to several (potential

Wireless Biological Electronic Sensors.

Science.gov (United States)

Cui, Yue

2017-10-09

The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

The short-term effects of antenna insulation thickness on path losses in wireless telemetry implants at microwave frequencies

Directory of Open Access Journals (Sweden)

Lukas Kneisz

2013-07-01

Full Text Available Various physiological parameters can be monitored non-invasively using wireless biotelemetry links. The development of sophisticated ultra low power consuming transceivers allows the transmission of large amounts of data from the inside of the body to an external receiver in real time at microwave frequencies.Antenna impedance matching is crucial for obtaining an acceptable propagation link budget in a wireless telemetry link. The dielectric properties of biological tissue induce detuning to transceiver antennas when implanted into the body. To counteract detuning problems, implant antennas are coated with biocompatible insulating material. The study investigates the propagation losses of a wireless communication link at different insulation thicknesses of medical grade silicone in the Industrial-Scientific-Medical (ISM radio band at 2.45 GHz. The wireless link consisted of an implantable unit which was placed between two pads of tissue substitute material and an external receiver which was connected to a laptop. Predefined data packets were transmitted from the implant, the received packets were analyzed, packet errors and packet losses were logged and the received signal strength indicator values (RSSI were recorded. Our results showed that the mean RSSI values of insulated transmitter antennas - embedded in tissue equivalent material - provide more safety distance to critical receiver sensitivity level than uncoated antennas.The conducted measurements let us conclude that with increasing thickness of the insulation layer, the antenna becomes less sensitive to detuning by adjacent tissue substitute material. Therefore tuned antennas are less influenced by the surrounding tissue after implantation.

Joint Mobile Data Collection and Wireless Energy Transfer in Wireless Rechargeable Sensor Networks.

Science.gov (United States)

Zhong, Ping; Li, Ya-Ting; Liu, Wei-Rong; Duan, Gui-Hua; Chen, Ying-Wen; Xiong, Neal

2017-08-16

In wireless rechargeable sensor networks (WRSNs), there is a way to use mobile vehicles to charge node and collect data. It is a rational pattern to use two types of vehicles, one is for energy charging, and the other is for data collecting. These two types of vehicles, data collection vehicles (DCVs) and wireless charging vehicles (WCVs), are employed to achieve high efficiency in both data gathering and energy consumption. To handle the complex scheduling problem of multiple vehicles in large-scale networks, a twice-partition algorithm based on center points is proposed to divide the network into several parts. In addition, an anchor selection algorithm based on the tradeoff between neighbor amount and residual energy, named AS-NAE, is proposed to collect the zonal data. It can reduce the data transmission delay and the energy consumption for DCVs' movement in the zonal. Besides, we design an optimization function to achieve maximum data throughput by adjusting data rate and link rate of each node. Finally, the effectiveness of proposed algorithm is validated by numerical simulation results in WRSNs.

Wireless Communications in Smart Rail Transportation Systems

Directory of Open Access Journals (Sweden)

César Briso-Rodríguez

2017-01-01

Full Text Available Railway, subway, airplane, and other transportation systems have drawn an increasing interest on the use of wireless communications for critical and noncritical services to improve performance, reliability, and passengers experience. Smart transportation systems require the use of critical communications for operation and control, and wideband services can be provided using noncritical communications. High speed train (HST is one of the best test cases for the analysis of communication links and specification of the general requirements for train control and supervision, passenger communications, and onboard and infrastructure wireless sensors. In this paper, we analyze in detail critical and noncritical networks mainly using the HST as a test case. First, the different types of links for smart rail transportation are described, specifying the main requirements of the transportation systems, communications, and their applications for different services. Then, we propose a network architecture and requirements of the communication technologies for critical and noncritical data. Finally, an analysis is made for the future technologies, including the fifth-generation (5G communications, millimeter wave (mmWave, terahertz (THz, and satellites for critical and high-capacity communications in transportation.

38.2-Gb/s Optical-Wireless Transmission in 75-110 GHz Based on Electrical OFDM with Optical Comb Expansion

DEFF Research Database (Denmark)

Deng, Lei; Pang, Xiaodan; Beltrán, Marta

2012-01-01

We demonstrate scalable optical comb- and heterodyning-based generation, optical and 1.3-m wireless transmission, and electrical heterodyne detection of multiband OFDM up to 38.2 Gb/s occupying 14.4-GHz RF bandwidth, for high-capacity optical-wireless links in 75-110 GHz....

Vigilance and iconic memory in children at high risk for alcoholism.

Science.gov (United States)

Steinhauer, S R; Locke, J; Hill, S Y

1997-07-01

Previous studies report reduced visual event-related potential (ERP) amplitudes in young males at high risk for alcoholism. These findings could involve difficulties at several stages of visual processing. This study was aimed at examining vigilance performance and iconic memory functions in children at high risk or low risk for alcoholism. Sustained vigilance and retrieval from iconic memory were evaluated in 54 (29 male) white children at high risk and 47 (25 male) white children at low risk for developing alcoholism. Children were also grouped according to gender and age (younger: 8-12 years; older: 13-18 years). No differences is visual sensitivity, response criterion or reaction time were associated with risk status on the degraded visual stimulus version of the Continuous Performance Test. For the Span of Apprehension, no differences were found due to risk status when only 1 or 5 distractors were presented, although with 9 distractors a significant effect of risk status was found when it was tested as an interaction with gender and age (decreased accuracy for older high-risk boys compared to older low-risk boys). These findings suggest that ERP deviations are not attributable to stages of visual processing deficits, but represent difficulty involving more complex utilization of information. Implications of these results are that the differences between high- and low-risk children that have been reported previously for visual ERP components (e.g., P300) are not attributable to deficits of attentional or iconic memory mechanisms.

The effects of luminance contrast, colour combinations, font, and search time on brand icon legibility.

Science.gov (United States)

Ko, Ya-Hsien

2017-11-01

This study explored and identified the effects of luminance contrast, colour combinations, font, and search time on brand icon legibility. A total of 108 participants took part in the experiment. As designed, legibility was measured as a function of the following independent variables: four levels of luminance contrast, sixteen target/background colour combinations, two fonts, and three search times. The results showed that a luminance contrast of 18:1 provided readers with the best legibility. Yellow on black, yellow on blue, and white on blue were the three most legible colour combinations. One of this study's unique findings was that colour combinations may play an even more important role than luminance contrast in the overall legibility of brand icon design. The 12-s search time corresponded with the highest legibility. Arial font was more legible than Times New Roman. These results provide some guidance for brand icon and product advertisement design. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance and energy efficiency in wireless self-organized networks

Energy Technology Data Exchange (ETDEWEB)

Gao, C.

2009-07-01

Self-organized packet radio networks (ad-hoc networks) and wireless sensor networks have got massive attention recently. One of critical problems in such networks is the energy efficiency, because wireless nodes are usually powered by battery. Energy efficiency design can dramatically increase the survivability and stability of wireless ad-hoc/sensor networks. In this thesis the energy efficiency has been considered at different protocol layers for wireless ad-hoc/sensor networks. The energy consumption of wireless nodes is inspected at the physical layer and MAC layer. At the network layer, some current routing protocols are compared and special attention has been paid to reactive routing protocols. A minimum hop analysis is given and according to the analysis result, a modification of AODV routing is proposed. A variation of transmit power can be also applied to clustering algorithm, which is believed to be able to control the scalability of network. Clustering a network can also improve the energy efficiency. We offer a clustering scheme based on the link state measurement and variation of transmit power of intra-cluster and inter-cluster transmission. Simulation shows that it can achieve both targets. In association with the clustering algorithm, a global synchronization scheme is proposed to increase the efficiency of clustering algorithm. The research attention has been also paid to self-organization for multi-hop cellular networks. A 2-hop 2-slot uplink proposal to infrastructure-based cellular networks. The proposed solution can significantly increase the throughput of uplink communication and reduce the energy consumption of wireless terminals. (orig.)

Assessment of proactive transmission power control for wireless sensor networks

NARCIS (Netherlands)

kotian, Roshan; Exarchakos, Georgios; Liotta, Antonio

2014-01-01

In order to prolong lifetime of Wireless Sensor Networks (WSN), Transmission Power Control (TPC) techniques are employed. The existing TPC schemes adjust the transmission power mostly reacting to changes at link quality between communicating nodes. Proactive TPC has been proposed in the recent past

Sensory exploitation and cultural transmission: the late emergence of iconic representations in human evolution.

Science.gov (United States)

Verpooten, Jan; Nelissen, Mark

2010-09-01

Iconic representations (i.e., figurative imagery and realistic art) only started to appear consistently some 45,000 years ago, although humans have been anatomically modern since 200,000-160,000 years ago. What explains this? Some authors have suggested a neurocognitive change took place, leading to a creative explosion, although this has been contested. Here, we examine the hypothesis that demographic changes caused cultural "cumulative adaptive evolution" and as such the emergence of modern symbolic behavior. This approach usefully explains the evolution of utilitarian skills and tools, and the creation of symbols to identify groups. However, it does not equally effectively explain the evolution of behaviors that may not be directly adaptive, such as the production of iconic representations like figurines and rock art. In order to shed light on their emergence, we propose to combine the above-mentioned cultural hypothesis with the concept of sensory exploitation. The concept essentially states that behavioral traits (in this case iconic art production) which exploit pre-existing sensory sensitivities will evolve if not hindered by costs (i.e., natural selection). In this view, iconic art traditions are evolved by piggy-backing on cumulative adaptive evolution. Since it is to date uncertain whether art has served any adaptive function in human evolution, parsimony demands paying more attention to the primary and a functional mechanism of sensory exploitation as opposed to mechanisms of models based exclusively on secondary benefits (such as Miller's, for instance, in which art is proposed to evolve as a sexual display of fitness).

Feasibility studies for a wireless 60 GHz tracking detector readout

International Nuclear Information System (INIS)

Dittmeier, S.; Schöning, A.; Soltveit, H.K.; Wiedner, D.

2016-01-01

The amount of data produced by highly granular silicon tracking detectors in high energy physics experiments poses a major challenge to readout systems. At high collision rates, e.g. at LHC experiments, only a small fraction of data can be read out with currently used technologies. To cope with the requirements of future or upgraded experiments new data transfer techniques are required which offer high data rates at low power and low material budget. Wireless technologies operating in the 60 GHz band or at higher frequencies offer high data rates and are thus a promising upcoming alternative to conventional data transmission via electrical cables or optical fibers. Using wireless technology, the amount of cables and connectors in detectors can be significantly reduced. Tracking detectors profit most from a reduced material budget as fewer secondary particle interactions (multiple Coulomb scattering, energy loss, etc.) improve the tracking performance in general. We present feasibility studies regarding the integration of the wireless technology at 60 GHz into a silicon tracking detector. We use spare silicon strip modules of the ATLAS experiment as test samples which are measured to be opaque in the 60 GHz range. The reduction of cross talk between links and the attenuation of reflections is studied. An estimate of the maximum achievable link density is given. It is shown that wireless links can be placed as close as 2 cm next to each other for a layer distance of 10 cm by exploiting one or several of the following measures: highly directive antennas, absorbers like graphite foam, linear polarization and frequency channeling. Combining these measures, a data rate area density of up to 11 Tb/(s·m"2) seems feasible. In addition, two types of silicon sensors are tested under mm-wave irradiation in order to determine the influence of 60 GHz data transmission on the detector performance: an ATLAS silicon strip sensor module and an HV-MAPS prototype for the Mu3e

Feasibility studies for a wireless 60 GHz tracking detector readout

Energy Technology Data Exchange (ETDEWEB)

Dittmeier, S., E-mail: dittmeier@physi.uni-heidelberg.de; Schöning, A.; Soltveit, H.K.; Wiedner, D.

2016-09-11

The amount of data produced by highly granular silicon tracking detectors in high energy physics experiments poses a major challenge to readout systems. At high collision rates, e.g. at LHC experiments, only a small fraction of data can be read out with currently used technologies. To cope with the requirements of future or upgraded experiments new data transfer techniques are required which offer high data rates at low power and low material budget. Wireless technologies operating in the 60 GHz band or at higher frequencies offer high data rates and are thus a promising upcoming alternative to conventional data transmission via electrical cables or optical fibers. Using wireless technology, the amount of cables and connectors in detectors can be significantly reduced. Tracking detectors profit most from a reduced material budget as fewer secondary particle interactions (multiple Coulomb scattering, energy loss, etc.) improve the tracking performance in general. We present feasibility studies regarding the integration of the wireless technology at 60 GHz into a silicon tracking detector. We use spare silicon strip modules of the ATLAS experiment as test samples which are measured to be opaque in the 60 GHz range. The reduction of cross talk between links and the attenuation of reflections is studied. An estimate of the maximum achievable link density is given. It is shown that wireless links can be placed as close as 2 cm next to each other for a layer distance of 10 cm by exploiting one or several of the following measures: highly directive antennas, absorbers like graphite foam, linear polarization and frequency channeling. Combining these measures, a data rate area density of up to 11 Tb/(s·m{sup 2}) seems feasible. In addition, two types of silicon sensors are tested under mm-wave irradiation in order to determine the influence of 60 GHz data transmission on the detector performance: an ATLAS silicon strip sensor module and an HV-MAPS prototype for the Mu3e

Indonesia and Africa: questioning the origins of some of Africa’s most famous icons

Directory of Open Access Journals (Sweden)

Robert Dick-Read

2006-04-01

Madagascar was only ever of secondary importance to Indonesians compared with mineral-rich Africa. But for centuries the Austronesian-speaking, Afro-Indonesian people of Madagascar maintained regular contact with the mainland giving rise to mixed societies, particularly in the Mozambique-Zimbabwe region. He believes the ancient Zimbabwe culture was in several ways linked with that of Madagascar, and that the vast ruin area of Nyanga was also connected. These cross-channel associations were gradually eclipsed by the domination of Arab-Shirazi colonisation down the East African Coast. There is a wealth of evidence that Indonesians rounded the Cape and sailed to West Africa. Several elements of Nigerian culture generally attributed to East-West overland movements or trans-Saharan Arab traders, are more likely to have reached the lower Niger regions by sea from Indonesia. Among these was the technology enabling the iconic ‘bronze’ artwork for which Nigeria is famous.

NPY2-receptor variation modulates iconic memory processes.

Science.gov (United States)

Arning, Larissa; Stock, Ann-Kathrin; Kloster, Eugen; Epplen, Jörg T; Beste, Christian

2014-08-01

Sensory memory systems are modality-specific buffers that comprise information about external stimuli, which represent the earliest stage of information processing. While these systems have been the subject of cognitive neuroscience research for decades, little is known about the neurobiological basis of sensory memory. However, accumulating evidence suggests that the glutamatergic system and systems influencing glutamatergic neural transmission are important. In the current study we examine if functional promoter variations in neuropeptide Y (NPY) and its receptor gene NPY2R affect iconic memory processes using a partial report paradigm. We found that iconic memory decayed much faster in individuals carrying the rare promoter NPY2R G allele which is associated with increased expression of the Y2 receptor. Possibly this effect is due to altered presynaptic inhibition of glutamate release, known to be modulated by Y2 receptors. Altogether, our results provide evidence that the functionally relevant single nucleotide polymorphism (SNP) in the NPY2R promoter gene affect circumscribed processes of early sensory processing, i.e. only the stability of information in sensory memory buffers. This leads us to suggest that especially the stability of information in sensory memory buffers depends on glutamatergic neural transmission and factors modulating glutamatergic turnover. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

Out of sight but not out of mind: the neurophysiology of iconic memory in the superior temporal sulcus.

Science.gov (United States)

Keysers, C; Xiao, D-K; Foldiak, P; Perrett, D I

2005-05-01

Iconic memory, the short-lasting visual memory of a briefly flashed stimulus, is an important component of most models of visual perception. Here we investigate what physiological mechanisms underlie this capacity by showing rapid serial visual presentation (RSVP) sequences with and without interstimulus gaps to human observers and macaque monkeys. For gaps of up to 93 ms between consecutive images, human observers and neurones in the temporal cortex of macaque monkeys were found to continue processing a stimulus as if it was still present on the screen. The continued firing of neurones in temporal cortex may therefore underlie iconic memory. Based on these findings, a neurophysiological vision of iconic memory is presented.

Enabling Wireless Avionics Intra-Communications

Science.gov (United States)

Torres, Omar; Nguyen, Truong; Mackenzie, Anne

2016-01-01

to model the propagation of a system in a "deployed" configuration versus a "stowed" configuration. The differences in relative field strength provide valuable information about the distribution of the field that can be used to engineer RF links with optimal radiated power and antenna configuration that accomplish the intended system reliability. Such modeling will be necessary in subsequent studies for managing multipath propagation characteristics inside a main cabin and to understand more complex environments, such as the inside wings, landing gear bays, cargo bays, avionics bays, etc. The results of the short research effort are described in the present document. The team puts forth a set of recommendations with the intention of informing the project and program leadership of the future work that, in the opinion of the EWAIC team, would assist the ECON team reach the intended goal of developing an all-wireless aircraft.

On the Relevance of Using OpenWireless Sensor Networks in Environment Monitoring

Directory of Open Access Journals (Sweden)

Antoine B. Bagula

2009-06-01

Full Text Available This paper revisits the problem of the readiness for field deployments of wireless- sensor networks by assessing the relevance of using Open Hardware and Software motes for environment monitoring. We propose a new prototype wireless sensor network that finetunes SquidBee motes to improve the life-time and sensing performance of an environment monitoring system that measures temperature, humidity and luminosity. Building upon two outdoor sensing scenarios, we evaluate the performance of the newly proposed energy-aware prototype solution in terms of link quality when expressed by the Received Signal Strength, Packet Loss and the battery lifetime. The experimental results reveal the relevance of using the Open Hardware and Software motes when setting up outdoor wireless sensor networks.

Optical wireless communications an emerging technology

CERN Document Server

Capsoni, Carlo; Ghassemlooy, Zabih; Boucouvalas, Anthony; Udvary, Eszter

2016-01-01

This book focuses on optical wireless communications (OWC), an emerging technology with huge potential for the provision of pervasive and reliable next-generation communications networks. It shows how the development of novel and efficient wireless technologies can contribute to a range of transmission links essential for the heterogeneous networks of the future to support various communications services and traffic patterns with ever-increasing demands for higher data-transfer rates. The book starts with a chapter reviewing the OWC field, which explains different sub-technologies (visible-light, ultraviolet (UV) and infrared (IR) communications) and introduces the spectrum of application areas (indoor, vehicular, terrestrial, underwater, intersatellite, deep space, etc.). This provides readers with the necessary background information to understand the specialist material in the main body of the book, which is in four parts. The first of these deals with propagation modelling and channel characterization of ...

Inter-flow and intra-flow interference mitigation routing in wireless mesh networks

OpenAIRE

Houaidia, Chiraz; Idoudi, Hanen; Van den Bossche, Adrien; Saidane, Leila; Val, Thierry

2017-01-01

In this paper, we address the problem of QoS support in an heterogeneous multi-rate wireless mesh network. We propose a new routing metric that provides information about link quality, based on PHY and MAC characteristics, including the link availability, the loss rate and the available bandwidth. This metric allows to apprehend inter-flow interferences and avoid bottleneck formation by balancing traffic load on the links. Based on the conflict graph model and calculation of maximal cliques, ...

Convergence of broadband optical and wireless access networks

Science.gov (United States)

Chang, Gee-Kung; Jia, Zhensheng; Chien, Hung-Chang; Chowdhury, Arshad; Hsueh, Yu-Ting; Yu, Jianjun

2009-01-01

This paper describes convergence of optical and wireless access networks for delivering high-bandwidth integrated services over optical fiber and air links. Several key system technologies are proposed and experimentally demonstrated. We report here, for the first ever, a campus-wide field trial demonstration of radio-over-fiber (RoF) system transmitting uncompressed standard-definition (SD) high-definition (HD) real-time video contents, carried by 2.4-GHz radio and 60- GHz millimeter-wave signals, respectively, over 2.5-km standard single mode fiber (SMF-28) through the campus fiber network at Georgia Institute of Technology (GT). In addition, subsystem technologies of Base Station and wireless tranceivers operated at 60 GHz for real-time video distribution have been developed and tested.

Unidirectional wireless power transfer using near-field plates

International Nuclear Information System (INIS)

Imani, Mohammadreza F.; Grbic, Anthony

2015-01-01

One of the obstacles preventing wireless power transfer from becoming ubiquitous is their leakage of power: high-amplitude electromagnetic fields that can interfere with other electronic devices, increase health concerns, or hinder power metering. In this paper, we present near-field plates (NFPs) as a novel method to tailor the electromagnetic fields generated by a wireless power transfer system while maintaining high efficiency. NFPs are modulated arrays or surfaces designed to form prescribed near-field patterns. The NFP proposed in this paper consists of an array of loaded loops that are designed to confine the electromagnetic fields of a resonant transmitting loop to the desired direction (receiving loop) while suppressing fields in other directions. The step-by-step design procedure for this device is outlined. Two NFPs are designed and examined in full-wave simulation. Their performance is shown to be in close agreement with the design predictions, thereby verifying the proposed design and operation. A NFP is also fabricated and experimentally shown to form a unidirectional wireless power transfer link with high efficiency

Unidirectional wireless power transfer using near-field plates

Energy Technology Data Exchange (ETDEWEB)

Imani, Mohammadreza F., E-mail: mohamad.imani@gmail.com [Center for Metamaterials and Integrated Plasmonics, Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Grbic, Anthony [Radiation Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2015-05-14

One of the obstacles preventing wireless power transfer from becoming ubiquitous is their leakage of power: high-amplitude electromagnetic fields that can interfere with other electronic devices, increase health concerns, or hinder power metering. In this paper, we present near-field plates (NFPs) as a novel method to tailor the electromagnetic fields generated by a wireless power transfer system while maintaining high efficiency. NFPs are modulated arrays or surfaces designed to form prescribed near-field patterns. The NFP proposed in this paper consists of an array of loaded loops that are designed to confine the electromagnetic fields of a resonant transmitting loop to the desired direction (receiving loop) while suppressing fields in other directions. The step-by-step design procedure for this device is outlined. Two NFPs are designed and examined in full-wave simulation. Their performance is shown to be in close agreement with the design predictions, thereby verifying the proposed design and operation. A NFP is also fabricated and experimentally shown to form a unidirectional wireless power transfer link with high efficiency.

The Effect of Iconic and Beat Gestures on Memory Recall in Greek's First and Second Language

OpenAIRE

Eleni Ioanna Levantinou

2016-01-01

Gestures play a major role in comprehension and memory recall due to the fact that aid the efficient channel of the meaning and support listeners’ comprehension and memory. In the present study, the assistance of two kinds of gestures (iconic and beat gestures) is tested in regards to memory and recall. The hypothesis investigated here is whether or not iconic and beat gestures provide assistance in memory and recall in Greek and in Greek speakers’ second language. Two gr...

A Regulation-Based Security Evaluation Method for Data Link in Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Claudio S. Malavenda

2014-01-01

Full Text Available This article presents a novel approach to the analysis of wireless sensor networks (WSN security, based on the regulations intended for wireless communication devices. Starting from the analysis and classification of attacks, countermeasures, and available protocols, we present the current state on secure communication stacks for embedded systems. The regulation analysis is based on civil EN 50150 and MIL STD-188-220, both applicable to WSN communications. Afterwards, starting from a list of known WSN attacks, we use a correspondence table to match WSN attacks with countermeasures required by regulations. This approach allows us to produce a precise security evaluation and classification methodology for WSN protocols. The results show that current protocols do not present a complete coverage of security issues. While this conclusion is already known for many WSN protocols, to the best of our knowledge this is the first time a complete methodology is proposed to base this assertion. Moreover, by using the proposed methodology, we are able to precisely identify the exposed threats for each WSN protocol under analysis.

Novel Reduced-Feedback Wireless Communication Systems

KAUST Repository

Shaqfeh, Mohammad Obaidah

2011-11-20

Modern communication systems apply channel-aware adaptive transmission techniques and dynamic resource allocation in order to exploit the peak conditions of the fading wireless links and to enable significant performance gains. However, conveying the channel state information among the users’ mobile terminals into the access points of the network consumes a significant portion of the scarce air-link resources and depletes the battery resources of the mobile terminals rapidly. Despite its evident drawbacks, the channel information feedback cannot be eliminated in modern wireless networks because blind communication technologies cannot support the ever-increasing transmission rates and high quality of experience demands of current ubiquitous services. Developing new transmission technologies with reduced-feedback requirements is sought. Network operators will benefit from releasing the bandwidth resources reserved for the feedback communications and the clients will enjoy the extended battery life of their mobile devices. The main technical challenge is to preserve the prospected transmission rates over the network despite decreasing the channel information feedback significantly. This is a noteworthy research theme especially that there is no mature theory for feedback communication in the existing literature despite the growing number of publications about the topic in the last few years. More research efforts are needed to characterize the trade-off between the achievable rate and the required channel information and to design new reduced-feedback schemes that can be flexibly controlled based on the operator preferences. Such schemes can be then introduced into the standardization bodies for consideration in next generation broadband systems. We have recently contributed to this field and published several journal and conference papers. We are the pioneers to propose a novel reduced-feedback opportunistic scheduling scheme that combines many desired features

Infrared and Visible links for medical Body Sensor Networks

OpenAIRE

Lebas , C; Sahuguede , S; Julien-Vergonjanne , A; Combeau , P; Aveneau , L

2018-01-01

International audience; — Our previous studies focused on channel simulation and performance evaluation of optical wireless links for medical body sensor networks. This allowed us to increase our expertise in this field and to propose here a full optical wireless bidirectional system named as LiFi communication system for medical monitoring applications. The full duplex bidirectional communication is based on an infrared uplink and visible downlink. The studied scenario considers a patient we...

Communicating global cardiovascular risk: are icon arrays better than numerical estimates in improving understanding, recall and perception of risk?

Science.gov (United States)

Ruiz, Jorge G; Andrade, Allen D; Garcia-Retamero, Rocio; Anam, Ramanakumar; Rodriguez, Remberto; Sharit, Joseph

2013-12-01

Experts recommend that adults have their global cardiovascular risk assessed. We investigated whether icon arrays increase understanding, recall, perception of CVR, and behavioral intent as compared with numerical information. Male outpatient veterans, at an intermediate to high cardiovascular risk participated in a randomized controlled trial of a computer tutorial presenting individualized risk. Message format was presented in 3 formats: percentages, frequencies, and frequencies with icon arrays. We assessed understanding immediately (T1) and recall at 20 min (T2) and 2 weeks (T3) after the intervention. We assessed perceptions of importance/seriousness, intent to adhere, and self-efficacy at T1. Self-reported adherence was assessed at T3. One-hundred and twenty male veterans participated. Age, education, race, health literacy and numeracy were comparable at baseline. There were no differences in understanding at T1 [p = .31] and recall at T3 [p = .10]. Accuracy was inferior with frequencies with icon arrays than percentages or frequencies at T2 [p ≤ .001]. There were no differences in perception of seriousness and importance for heart disease, behavioral intent, self-efficacy, actual adherence and satisfaction. Icon arrays may impair short-term recall of CVR. Icon arrays will not necessarily result in better understanding and recall of medical risk in all patients. Published by Elsevier Ireland Ltd.

An Energy-Efficient Link Layer Protocol for Reliable Transmission over Wireless Networks

Directory of Open Access Journals (Sweden)

Iqbal Adnan

2009-01-01

Full Text Available In multihop wireless networks, hop-by-hop reliability is generally achieved through positive acknowledgments at the MAC layer. However, positive acknowledgments introduce significant energy inefficiencies on battery-constrained devices. This inefficiency becomes particularly significant on high error rate channels. We propose to reduce the energy consumption during retransmissions using a novel protocol that localizes bit-errors at the MAC layer. The proposed protocol, referred to as Selective Retransmission using Virtual Fragmentation (SRVF, requires simple modifications to the positive-ACK-based reliability mechanism but provides substantial improvements in energy efficiency. The main premise of the protocol is to localize bit-errors by performing partial checksums on disjoint parts or virtual fragments of a packet. In case of error, only the corrupted virtual fragments are retransmitted. We develop stochastic models of the Simple Positive-ACK-based reliability, the previously-proposed Packet Length Optimization (PLO protocol, and the SRVF protocol operating over an arbitrary-order Markov wireless channel. Our analytical models show that SRVF provides significant theoretical improvements in energy efficiency over existing protocols. We then use bit-error traces collected over different real networks to empirically compare the proposed and existing protocols. These experimental results further substantiate that SRVF provides considerably better energy efficiency than Simple Positive-ACK and Packet Length Optimization protocols.

SmartMIMO: An Energy-Aware Adaptive MIMO-OFDM Radio Link Control for Next-Generation Wireless Local Area Networks

Directory of Open Access Journals (Sweden)

Wim Dehaene

2007-12-01

Full Text Available Multiantenna systems and more particularly those operating on multiple input and multiple output (MIMO channels are currently a must to improve wireless links spectrum efficiency and/or robustness. There exists a fundamental tradeoff between potential spectrum efficiency and robustness increase. However, multiantenna techniques also come with an overhead in silicon implementation area and power consumption due, at least, to the duplication of part of the transmitter and receiver radio front-ends. Although the area overhead may be acceptable in view of the performance improvement, low power consumption must be preserved for integration in nomadic devices. In this case, it is the tradeoff between performance (e.g., the net throughput on top of the medium access control layer and average power consumption that really matters. It has been shown that adaptive schemes were mandatory to avoid that multiantenna techniques hamper this system tradeoff. In this paper, we derive smartMIMO: an adaptive multiantenna approach which, next to simply adapting the modulation and code rate as traditionally considered, decides packet-per-packet, depending on the MIMO channel state, to use either space-division multiplexing (increasing spectrum efficiency, space-time coding (increasing robustness, or to stick to single-antenna transmission. Contrarily to many of such adaptive schemes, the focus is set on using multiantenna transmission to improve the link energy efficiency in real operation conditions. Based on a model calibrated on an existing reconfigurable multiantenna transceiver setup, the link energy efficiency with the proposed scheme is shown to be improved by up to 30% when compared to nonadaptive schemes. The average throughput is, on the other hand, improved by up to 50% when compared to single-antenna transmission.

SmartMIMO: An Energy-Aware Adaptive MIMO-OFDM Radio Link Control for Next-Generation Wireless Local Area Networks

Directory of Open Access Journals (Sweden)

Dehaene Wim

2007-01-01

Full Text Available Multiantenna systems and more particularly those operating on multiple input and multiple output (MIMO channels are currently a must to improve wireless links spectrum efficiency and/or robustness. There exists a fundamental tradeoff between potential spectrum efficiency and robustness increase. However, multiantenna techniques also come with an overhead in silicon implementation area and power consumption due, at least, to the duplication of part of the transmitter and receiver radio front-ends. Although the area overhead may be acceptable in view of the performance improvement, low power consumption must be preserved for integration in nomadic devices. In this case, it is the tradeoff between performance (e.g., the net throughput on top of the medium access control layer and average power consumption that really matters. It has been shown that adaptive schemes were mandatory to avoid that multiantenna techniques hamper this system tradeoff. In this paper, we derive smartMIMO: an adaptive multiantenna approach which, next to simply adapting the modulation and code rate as traditionally considered, decides packet-per-packet, depending on the MIMO channel state, to use either space-division multiplexing (increasing spectrum efficiency, space-time coding (increasing robustness, or to stick to single-antenna transmission. Contrarily to many of such adaptive schemes, the focus is set on using multiantenna transmission to improve the link energy efficiency in real operation conditions. Based on a model calibrated on an existing reconfigurable multiantenna transceiver setup, the link energy efficiency with the proposed scheme is shown to be improved by up to 30% when compared to nonadaptive schemes. The average throughput is, on the other hand, improved by up to 50% when compared to single-antenna transmission.

Resilient Disaster Network Based on Software Defined Cognitive Wireless Network Technology

Directory of Open Access Journals (Sweden)

Goshi Sato

2015-01-01

Full Text Available In order to temporally recover the information network infrastructure in disaster areas from the Great East Japan Earthquake in 2011, various wireless network technologies such as satellite IP network, 3G, and Wi-Fi were effectively used. However, since those wireless networks are individually introduced and installed but not totally integrated, some of networks were congested due to the sudden network traffic generation and unbalanced traffic distribution, and eventually the total network could not effectively function. In this paper, we propose a disaster resilient network which integrates various wireless networks into a cognitive wireless network that users can use as an access network to the Internet at the serious disaster occurrence. We designed and developed the disaster resilient network based on software defined network (SDN technology to automatically select the best network link and route among the possible access networks to the Internet by periodically monitoring their network states and evaluate those using extended AHP method. In order to verify the usefulness of our proposed system, a prototype system is constructed and its performance is evaluated.

Experimental Effects of Acute Exercise on Iconic Memory, Short-Term Episodic, and Long-Term Episodic Memory

Directory of Open Access Journals (Sweden)

Danielle Yanes

2018-06-01

Full Text Available The present experiment evaluated the effects of acute exercise on iconic memory and short- and long-term episodic memory. A two-arm, parallel-group randomized experiment was employed (n = 20 per group; Mage = 21 year. The experimental group engaged in an acute bout of moderate-intensity treadmill exercise for 15 min, while the control group engaged in a seated, time-matched computer task. Afterwards, the participants engaged in a paragraph-level episodic memory task (20 min delay and 24 h delay recall as well as an iconic memory task, which involved 10 trials (at various speeds from 100 ms to 800 ms of recalling letters from a 3 × 3 array matrix. For iconic memory, there was a significant main effect for time (F = 42.9, p < 0.001, η2p = 0.53 and a trend towards a group × time interaction (F = 2.90, p = 0.09, η2p = 0.07, but no main effect for group (F = 0.82, p = 0.37, η2p = 0.02. The experimental group had higher episodic memory scores at both the baseline (19.22 vs. 17.20 and follow-up (18.15 vs. 15.77, but these results were not statistically significant. These findings provide some suggestive evidence hinting towards an iconic memory and episodic benefit from acute exercise engagement.

Icon Painters of the Nizhniy Novgorod Volga Region of the XVII Century

Directory of Open Access Journals (Sweden)

Veronicka N. Belyaeva

2012-09-01

Full Text Available The author considers specificity and basic difficulties of biographies of the icon painters of the Nizhniy Novgorod Volga region of the XVII-th century restore. The data on the masters are cites.

The bay of Cattaro (Kotor school of icon-painting 1680-1860

Directory of Open Access Journals (Sweden)

Stošić Ljiljana

2014-01-01

Full Text Available Relying on post-Byzantine tradition, eleven painters from five generations of the Dimitrijević-Rafailović family, accompanied by Maksim Tujković, painted several thousand icons and several hundred iconostases between the late seventeenth and the second half of the nineteenth century. They worked in major Orthodox Christian monasteries in Montenegro, Kosovo and Metohija, Bosnia and Herzegovina and Dalmatia, but their works can mostly be found in modest village churches in the Bay of Kotor (Cattaro and on the South Adriatic coast. The decoration of these churches was financially supported by the local population headed by elders. Along with a reconstruction of their biographies and a chronological overview of their major works, this paper seeks to trace stylistic changes in the Bay of Kotor school of icon-painting. While simply varying a thematic repertory established in earlier periods, the painters from the Bay of Kotor were gradually introducing new details and themes adopted from Western European Baroque art under indirect influences coming from the monastery of Hilandar, Corfu, Venice and Russia. This process makes this indigenous school of icon-painting, which spanned almost two centuries, comparable to the work of Serbian traditional religious painters (zografs and illuminators active north of the Sava and Danube rivers after the Great Migration of the Serbs (1690. Despite differences between the two, which resulted from different cultural and historical circumstances in which Serbs lived under Ottoman, Venetian and Habsburg rules, similarities in iconography and style, which were inspired by an urge to counteract proselytic pressures, are considerably more important.

Hybrid CATV/MMW/BB lightwave transmission system based on fiber-wired/fiber-wireless/fiber-VLLC integrations.

Science.gov (United States)

Li, Chung-Yi; Lu, Hai-Han; Lu, Ting-Chieh; Chu, Chien-An; Chen, Bo-Rui; Lin, Chun-Yu; Peng, Peng-Chun

2015-12-14

A hybrid lightwave transmission system for cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission based on fiber-wired/fiber-wireless/fiber-visible laser light communication (VLLC) integrations is proposed and demonstrated. For down-link transmission, the light is intensity-modulated with 50-550 MHz CATV signal and optically promoted from 25 GHz radio frequency (RF) signal to 10 Gbps/50 GHz and 20 Gbps/100 GHz MMW data signals based on fiber-wired and fiber-wireless integrations. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 40-km single-mode fiber (SMF) and a 10-m RF wireless transport. For up-link transmission, the light is successfully intensity-remodulated with 5-Gbps BB data stream based on fiber-VLLC integration. Good BER performance is achieved over a 40-km SMF and a 10-m free-space VLLC transport. Such a hybrid CATV/MMW/BB lightwave transmission system is an attractive alternative, it gives the benefits of a communication link for broader bandwidth and higher transmission rate.

Towards convergence of wireless and wireline signal transport in broadband access networks

DEFF Research Database (Denmark)

Yu, Xianbin; Prince, Kamau; Tafur Monroy, Idelfonso

2010-01-01

Hybrid optical wireless access networks are to play an important role in the realization of the vision of delivery of broadband services to the end-user any time, anywhere and at affordable costs. We present results of experiments conducted over a field deployed optical fibre links we successfull...... demonstrated converged wireless and wireline signal transport over a common fibre infrastructure. The type of signal used in this field deployed experiments cover WiMax, Impulse-radio ultra-wideband (UWB) and coherent transmission of baseband QPSK and radio-over-fibre signals....

Complex networks-based energy-efficient evolution model for wireless sensor networks

Energy Technology Data Exchange (ETDEWEB)

Zhu Hailin [Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia, Beijing University of Posts and Telecommunications, P.O. Box 106, Beijing 100876 (China)], E-mail: zhuhailin19@gmail.com; Luo Hong [Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia, Beijing University of Posts and Telecommunications, P.O. Box 106, Beijing 100876 (China); Peng Haipeng; Li Lixiang; Luo Qun [Information Secure Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China)

2009-08-30

Based on complex networks theory, we present two self-organized energy-efficient models for wireless sensor networks in this paper. The first model constructs the wireless sensor networks according to the connectivity and remaining energy of each sensor node, thus it can produce scale-free networks which have a performance of random error tolerance. In the second model, we not only consider the remaining energy, but also introduce the constraint of links to each node. This model can make the energy consumption of the whole network more balanced. Finally, we present the numerical experiments of the two models.

Complex networks-based energy-efficient evolution model for wireless sensor networks

International Nuclear Information System (INIS)

Zhu Hailin; Luo Hong; Peng Haipeng; Li Lixiang; Luo Qun

2009-01-01

Based on complex networks theory, we present two self-organized energy-efficient models for wireless sensor networks in this paper. The first model constructs the wireless sensor networks according to the connectivity and remaining energy of each sensor node, thus it can produce scale-free networks which have a performance of random error tolerance. In the second model, we not only consider the remaining energy, but also introduce the constraint of links to each node. This model can make the energy consumption of the whole network more balanced. Finally, we present the numerical experiments of the two models.

Achieving single channel, full duplex wireless communication