976 resultados para Network Connectivity
Resumo:
The objective of the thesis was to evaluate business potential of wireless local area networks (WLAN, Wireless LAN). At first, the scope of business potential evaluation of technology was introduced. Next, a general framework of business potential evaluation of technology based on literature was presented. In addition, convergence of cellular networks and data networks was studied in order to get an insight of current situation of mobile telecommunications industry. Finally, wireless local area networks business potential was evaluated. A wireless local area network is a data communication system, which combines data connectivity with mobility and is implemented in unlicensed frequency bands, allowing new business opportunities to emerge. The main markets of WLAN are corporate networks, public area networks and access networks. At the moment the penetration of WLAN terminals is low which derives to low demand of wireless LAN services. In addition, unlicensed spectrum forces the teleoperators to set the service price relatively low. The business potential is in integrating wireless LANs to cellular networks and in offering value added services to end users. The future of wireless LAN is to be complementary network to cellular networks. In this vision cellular networks provide voice and low data services and broadband wireless networks enable multimedia services.
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[spa] En este artículo, analizamos la volatilidad agregada de una economía estilizada donde los agentes estann conectados en redes. Si hay relaciones estratégicas entre las acciones de los agentes, choques idiosincráticos pueden generar fluctuaciones agregadas. Demonstramos que la volatilidad agregada depende de la estructura de redes de la economía de dos maneras. Por un lado, si hay más conexiones en la economía en su conjunto, la volatilidad agregada es más baja. Por otro lado, si las conexiones están más concentradas, la volatilidad agregada es más alta. Presentamos una aplicación de nuestras predicciones teóricas que utiliza datos de EEUU de conexiones intrasectoriales y de diversificación de las empresas.
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Quantitative phase microscopy (QPM) has recently emerged as a new powerful quantitative imaging technique well suited to noninvasively explore a transparent specimen with a nanometric axial sensitivity. In this review, we expose the recent developments of quantitative phase-digital holographic microscopy (QP-DHM). Quantitative phase-digital holographic microscopy (QP-DHM) represents an important and efficient quantitative phase method to explore cell structure and dynamics. In a second part, the most relevant QPM applications in the field of cell biology are summarized. A particular emphasis is placed on the original biological information, which can be derived from the quantitative phase signal. In a third part, recent applications obtained, with QP-DHM in the field of cellular neuroscience, namely the possibility to optically resolve neuronal network activity and spine dynamics, are presented. Furthermore, potential applications of QPM related to psychiatry through the identification of new and original cell biomarkers that, when combined with a range of other biomarkers, could significantly contribute to the determination of high risk developmental trajectories for psychiatric disorders, are discussed.
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PURPOSE: Small cell carcinomas of the bladder (SCCB) account for fewer than 1% of all urinary bladder tumors. There is no consensus regarding the optimal treatment for SCCB. METHODS AND MATERIALS: Fifteen academic Rare Cancer Network medical centers contributed SCCB cases. The eligibility criteria were as follows: pure or mixed SCC; local, locoregional, and metastatic stages; and age ≥18 years. The overall survival (OS) and disease-free survival (DFS) were calculated from the date of diagnosis according to the Kaplan-Meier method. The log-rank and Wilcoxon tests were used to analyze survival as functions of clinical and therapeutic factors. RESULTS: The study included 107 patients (mean [±standard deviation, SD] age, 69.6 [±10.6] years; mean follow-up time, 4.4 years) with primary bladder SCC, with 66% of these patients having pure SCC. Seventy-two percent and 12% of the patients presented with T2-4N0M0 and T2-4N1-3M0 stages, respectively, and 16% presented with synchronous metastases. The most frequent curative treatments were radical surgery and chemotherapy, sequential chemotherapy and radiation therapy, and radical surgery alone. The median (interquartile range, IQR) OS and DFS times were 12.9 months (IQR, 7-32 months) and 9 months (IQR, 5-23 months), respectively. The metastatic, T2-4N0M0, and T2-4N1-3M0 groups differed significantly (P=.001) in terms of median OS and DFS. In a multivariate analysis, impaired creatinine clearance (OS and DFS), clinical stage (OS and DFS), a Karnofsky performance status <80 (OS), and pure SCC histology (OS) were independent and significant adverse prognostic factors. In the patients with nonmetastatic disease, the type of treatment (ie radical surgery with or without adjuvant chemotherapy vs conservative treatment) did not significantly influence OS or DFS (P=.7). CONCLUSIONS: The prognosis for SCCB remains poor. The finding that radical cystectomy did not influence DFS or OS in the patients with nonmetastatic disease suggests that conservative treatment is appropriate in this situation.
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Children who sustain a prenatal or perinatal brain injury in the form of a stroke develop remarkably normal cognitive functions in certain areas, with a particular strength in language skills. A dominant explanation for this is that brain regions from the contralesional hemisphere "take over" their functions, whereas the damaged areas and other ipsilesional regions play much less of a role. However, it is difficult to tease apart whether changes in neural activity after early brain injury are due to damage caused by the lesion or by processes related to postinjury reorganization. We sought to differentiate between these two causes by investigating the functional connectivity (FC) of brain areas during the resting state in human children with early brain injury using a computational model. We simulated a large-scale network consisting of realistic models of local brain areas coupled through anatomical connectivity information of healthy and injured participants. We then compared the resulting simulated FC values of healthy and injured participants with the empirical ones. We found that the empirical connectivity values, especially of the damaged areas, correlated better with simulated values of a healthy brain than those of an injured brain. This result indicates that the structural damage caused by an early brain injury is unlikely to have an adverse and sustained impact on the functional connections, albeit during the resting state, of damaged areas. Therefore, these areas could continue to play a role in the development of near-normal function in certain domains such as language in these children.
Resumo:
[spa] En este artículo, analizamos la volatilidad agregada de una economía estilizada donde los agentes estann conectados en redes. Si hay relaciones estratégicas entre las acciones de los agentes, choques idiosincráticos pueden generar fluctuaciones agregadas. Demonstramos que la volatilidad agregada depende de la estructura de redes de la economía de dos maneras. Por un lado, si hay más conexiones en la economía en su conjunto, la volatilidad agregada es más baja. Por otro lado, si las conexiones están más concentradas, la volatilidad agregada es más alta. Presentamos una aplicación de nuestras predicciones teóricas que utiliza datos de EEUU de conexiones intrasectoriales y de diversificación de las empresas.
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The thesis presents an overview of third generation of IP telephony. The architecture of 3G IP Telephony and its components are described. The main goal of the thesis is to investigate the interface between the Call Processing Server and Multimedia IP Networks. The interface functionality, proposed protocol stack and a general description are presented in the thesis. To provide useful services, 3G IP Telephony requires a set of control protocols for connection establishment, capabilities exchange and conference control. The Session Initiation Protocol (SIP) and the H.323 are two protocols that meet these needs. In the thesis these two protocols are investigated and compared in terms of Complexity, Extensibility, Scalability, Services, Resource Utilization and Management.
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UMTS is a 3rd generation telecommunication system, which introduces new network architecture. The change in the network architecture introduces new logical network nodes and changes the role of existing nodes in the network. This architecture changes the current vertically specialized network into a horizontally layered structure. In practice, the layering means that different levels in network hierarchy are separated, and they communicate over well-specified interfaces. The Connectivity Layer, at the bottom of the UMTS network architecture, contains Media Gateways (MGW). The GSM radio access network and UMTS access network are connected to the connectivity network via a MGW. External networks, e.g. ISDN networks, are accessed via other MGWs. The user plane is transported across the connectivity network between/via MGWs. ATM network is used as the backbone in Ericsson’s UMTS core network release 2.0. The main goal of this thesis is to study how the MGW is used to bridge ATM and TDM networks. The Circuit Emulation Service (CES) for ATM is studied, as the conversion from TDM to ATM is made according it. The transportation is made using AAL2 and the issues that it has with voice traffic are studied. The implementation and usage of TDM switching service in MGW are described in detail.
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During the last half decade the popularity of different peer-to-peer applications has grown tremendously. Traditionally only desktop-class computers with fixed line network connections have been powerful enough to utilize peer-to-peer. However, the situation is about to change. The rapid development of wireless terminals will soon enable peer-to-peer applications on these devices as well as on desktops. Possibilities are further enhanced by the upcoming high-bandwidth cellular networks. In this thesis the applicability and implementation alternatives of an existing peer-to-peer system are researched for two target platforms: Linux powered iPaq and Symbian OS based smartphone. The result is a peer-to-peer middleware component suitable for mobile terminals. It works on both platforms and utilizes Bluetooth networking technology. The implemented software platforms are compatible with each other and support for additional network technologies can be added with a minimal effort.
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The purpose of the research is to define practical profit which can be achieved using neural network methods as a prediction instrument. The thesis investigates the ability of neural networks to forecast future events. This capability is checked on the example of price prediction during intraday trading on stock market. The executed experiments show predictions of average 1, 2, 5 and 10 minutes’ prices based on data of one day and made by two different types of forecasting systems. These systems are based on the recurrent neural networks and back propagation neural nets. The precision of the predictions is controlled by the absolute error and the error of market direction. The economical effectiveness is estimated by a special trading system. In conclusion, the best structures of neural nets are tested with data of 31 days’ interval. The best results of the average percent of profit from one transaction (buying + selling) are 0.06668654, 0.188299453, 0.349854787 and 0.453178626, they were achieved for prediction periods 1, 2, 5 and 10 minutes. The investigation can be interesting for the investors who have access to a fast information channel with a possibility of every-minute data refreshment.
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Neljännen sukupolven mobiiliverkot kokoaa kaikki tietoliikenneverkot ja palvelut Internetin ympärille. Tämä mullistus muuttaa vanhat vertikaaliset tietoliikenneverkot joissa yhden tietoliikenneverkon palvelut ovat saatavissa vain kyseisen verkon päätelaitteille horisontaaliseksi malliksi jossa päätelaitteet käyttävät omaa verkkoansa pääsynä Internetin palveluihin. Tämä diplomityö esittelee idean paikallisista palveluista neljännen sukupolven mobiiliverkossa. Neljännen sukupolven mobiiliverkko yhdistää perinteiset televerkkojen palvelut ja Internet palvelut sekä mahdollistaa uuden tyyppisten palveluiden luonnin. TCP/IP protokollien ja Internetin evoluutio on esitelty. Laajakaistaiset, lyhyen kantaman radiotekniikat joita käytetään langattomana yhteytenä Internetiin on käsitelty. Evoluutio kohti neljännen sukupolven mobiiliverkkoja on kuvattu esittelemällä vanhat, nykyiset ja tulevat mobiiliverkot sekä niiden palvelut. Ennustukset palveluiden ja markkinoiden tulevaisuuden kehityksestä on käsitelty. Neljännen sukupolven mobiiliverkon arkkitehtuuri mahdollistaa paikalliset palvelut jotka ovat saatavilla vain yhdessä paikallisessa 4G verkossa. Paikalliset palvelut voidaan muunnella jokaiselle käyttäjälle erikseen käyttäen profiili-informaatiota ja paikkatietoa. Työssä on pohdittu paikallisten palveluiden käyttökelpoisuutta ja mahdollisuuksia käyttäen Lappeenrannan teknillisen korkeakoulun 4G projektin palvelupilotin tuloksia.
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Social interactions are a very important component in people"s lives. Social network analysis has become a common technique used to model and quantify the properties of social interactions. In this paper, we propose an integrated framework to explore the characteristics of a social network extracted from multimodal dyadic interactions. For our study, we used a set of videos belonging to New York Times" Blogging Heads opinion blog. The Social Network is represented as an oriented graph, whose directed links are determined by the Influence Model. The links" weights are a measure of the"influence" a person has over the other. The states of the Influence Model encode automatically extracted audio/visual features from our videos using state-of-the art algorithms. Our results are reported in terms of accuracy of audio/visual data fusion for speaker segmentation and centrality measures used to characterize the extracted social network.
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Mobiiliviestintään käytetystä lyhytsanomapalvelusta (Short Messaging Service, SMS) on tullut ilmiömäinen menestys. SMS-palvelulle on tulossa seuraaja, jota kutsutaan monimediaviestipalveluksi (Multimedia Messaging Service, MMS). MMS-viestit voivat sisältää useita erilaisia kuva-, ääni- ja videoformaatteja. Vaikka yhteensopimattomia SMS-keskuksia yhdistämään tarvitaan Intellitel Messaging Gatewayn kaltaisia sanomanvälitystuotteita, ei tällainen SMS-keskeinen lähestyminen sanomanvälitykseen ole MMS-kykyisen sanomanvälittimen kannalta järkevä ratkaisu. MMS-kykyisen sanomanvälittimen täytyy lisätä arvoa itse sanomanvälitysprosessiin, jotta tuotteesta tulisi menestyksekäs. Tässä työssä käsitellään MMS-sanomanvälityksen ongelmallisuuksia. Erityisesti painotetaan MMS-kykyisen sanomanvälittimen kehittämistä olemassaolevasta SMS-sanomanvälitintuotteesta, sekä selvitetään syitä arvonlisäyksen välttämättömyydelle. Työssä esitetään myös erilaisia arvonlisäystapoja MMS-sanomanvälitykseen. Eräitä esitetyistä arvonlisäystavoista käytetään käytännön osassa toteutetussa Nokian MMS-keskuksen MM7/VAS-rajapintaan kytkeytymään kykenevässä sanomanvälityskomponentissa.
Resumo:
Tutkimuksen tavoitteena oli selvittää miten Bluetooth-teknologia voi vaikuttaa ICT-alan arvoverkkoon ja alan toimijoiden rooleihin. Tutkimuksessa käytettiin kvalitatiivisia menetelmiä ja siinä oli piirteitä tulevaisuuden tutkimuksesta, koska myös eksploratiivisia menetelmiä käytettiin. Tutkimus perustui laajalti kirjallisuuteen ja artikkeleihin, joiden perusteella muodostettiin skenaarioita ICT-alan tulevaisuuden arvoverkosta. Tutkimus sisälsi myös empiirisen osion, jossa järjestettiin kaksi ryhmäkeskustelua, joissa alan toimijat keskustelivat muodostetuista skenaarioista sekä yleisemmin Bluetoothin vaikutuksista arvoverkkoon. Tutkimuksen mukaan ICT-alan arvoverkko tulevaisuudessa on rakenteeltaan strateginen arvoverkko, jota johtaa eri toimija erilaisissa markkinatilanteissa. Verkon strateginen keskus voi muuttua ajan kuluessa kun Bluetoothin sovelluskohteet lisääntyvät ja se voi vaihdella markkina-alueesta toiseen. Bluetooth luo uuden kommunikaatiokanavan nykyisten rinnalle ja se voi paikallisesti korvata nykyisten kanavien käytön tiedon siirrossa. Bluetooth voi synnyttää lukuisia uusia liiketoimintamahdollisuuksia ja sen avulla voidaan tuottaa lisäarvopalveluita. Suurimpien muutosten voidaan olettaa koskevan teleoperaattoreiden ja sisällöntuottajien liiketoimintaa.
Resumo:
ABSTRACT The present study aimed at evaluating the heterotic group formation in guava based on quantitative descriptors and using artificial neural network (ANN). For such, we evaluated eight quantitative descriptors. Large genetic variability was found for the eight quantitative traits in the 138 genotypes of guava. The artificial neural network technique determined that the optimal number of groups was three. The grouping consistency was determined by linear discriminant analysis, which obtained classification percentage of the groups, with a value of 86 %. It was concluded that the artificial neural network method is effective to detect genetic divergence and heterotic group formation.