961 resultados para TDMA (Time Division Multiple Access)


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e Computadores

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Bit serial, processing, digital signal processing, transmission, time division, linear programming, linear optimization

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fat embolism syndrome is a rare complication that develops after extended soft tissue disruption by liposuction, in particular if combined with time consuming, multiple procedures. Early signs are non-specific and often not considered, so that diagnosis and correct management may be delayed. We report a case in which liposuction combined with other aesthetic surgical procedures caused a fat embolism syndrome in a 46-year-old woman, which was followed by multiple organ failure and the development of sepsis with perimammary abscesses. Extended liposuction of the abdomen and thighs, bilateral augmentation mammaplasty, and stripping of both greater saphenous veins were combined.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

It is well known that multiple-input multiple-output (MIMO) techniques can bring numerous benefits, such as higher spectral efficiency, to point-to-point wireless links. More recently, there has been interest in extending MIMO concepts tomultiuser wireless systems. Our focus in this paper is on network MIMO, a family of techniques whereby each end user in a wireless access network is served through several access points within its range of influence. By tightly coordinating the transmission and reception of signals at multiple access points, network MIMO can transcend the limits on spectral efficiency imposed by cochannel interference. Taking prior information-theoretic analyses of networkMIMO to the next level, we quantify the spectral efficiency gains obtainable under realistic propagation and operational conditions in a typical indoor deployment. Our study relies on detailed simulations and, for specificity, is conducted largely within the physical-layer framework of the IEEE 802.16e Mobile WiMAX system. Furthermore,to facilitate the coordination between access points, we assume that a high-capacity local area network, such as Gigabit Ethernet,connects all the access points. Our results confirm that network MIMO stands to provide a multiple-fold increase in spectralefficiency under these conditions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We examine a multiple-access communication system in which multiuser detection is performed without knowledge of the number of active interferers. Using a statistical-physics approach, we compute the single-user channel capacity and spectral efficiency in the large-system limit.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper describes a study that aimed to identify research priorities for the care of infants, children and adolescents at the sole tertiary referral hospital for children in Western Australia. The secondary aim was to stimulate nurses to explore clinical problems that would require further inquiry. Background. Planning for research is an essential stage of research development; involving clinicians in this exercise is likely to foster research partnerships that are pertinent to clinical practice. Nursing research priorities for the paediatric population have not previously been reported in Australia. Design. Delphi study. Method. Over 12 months in 2005-2006, a three-round questionnaire, using the Delphi technique, was sent to a randomly selected sample of registered nurses. This method was used to identify and prioritise nursing research topics relevant to the patient and the family. Content analysis was used to analyse Round I data and descriptive statistics for Round II and III data. Results. In Round I, 280 statements were identified and reduced to 37 research priorities. Analysis of data in subsequent rounds identified the top two priority research areas as (1) identification of strategies to reduce medication incidents (Mean = 6 center dot 47; SD 0 center dot 88) and (2) improvement in pain assessment and management (Mean = 6; SD 1 center dot 38). Additional comments indicated few nurses access the scientific literature or use research findings because of a lack of time or electronic access. Conclusions. Thirty-seven research priorities were identified. The identification of research priorities by nurses provided research direction for the health service and potentially other similar health institutions for children and adolescents in Australia and internationally. Relevance to clinical practice. The nurse participants showed concern about the safety of care and the well-being of children and their families. This study also enabled the identification of potential collaborative research and development of pain management improvement initiatives.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

BACKGROUND: Despite major advances in care of premature infants, survivors exhibit mild cognitive deficits in around 40%. Beside severe intraventricular haemorrhages (IVH) and cystic periventricular leucomalacia (PVL), more subtle patterns such as grade I and II IVH, punctuate WM lesions and diffuse PVL might be linked to the cognitive deficits. Grey matter disease is also recognized to contribute to long-term cognitive impairment.¦OBJECTIVE: We intend to use novel MR techniques to study more precisely the different injury patterns. In particular MP2RAGE (magnetization prepared dual rapid echo gradient) produces high-resolution quantitative T1 relaxation maps. This contrast is known to reflect tissue anomalies such as white matter injury in general and dysmyelination in particular. We also used diffusion tensor imaging, a quantitative technique known to reflect white matter maturation and disease.¦DESIGN/METHODS: All preterm infants born under 30 weeks of GA were included. Serial 3T MR-imaging using a neonatal head-coil at DOL 3, 10 and at term equivalent age (TEA), using DTI and MP2RAGE sequences was performed. MP2RAGE generates a T1 map and allows calculating the relaxation time T1. Multiple measurements were performed for each exam in 12 defined white and grey matter ROIs.¦RESULTS: 16 patients were recruited: mean GA 27 2/7 w (191,2d SD±10,8), mean BW 999g (SD±265). 39 MRIs were realized (12 early: mean 4,83d±1,75, 13 late: mean 18,77d±8,05 and 14 at TEA: 88,91d±8,96). Measures of relaxation time T1 show a gradual and significant decrease over time (for ROI PLIC mean±SD in ms: 2100.53±102,75, 2116,5±41,55 and 1726,42±51,31 and for ROI central WM: 2302,25±79,02, 2315,02±115,02 and 1992,7±96,37 for early, late and TEA MR respectively). These trends are also observed in grey matter area, especially in thalamus. Measurements of ADC values show similar monotonous decrease over time.¦CONCLUSIONS: From these preliminary results, we conclude that quantitative MR imaging in very preterm infants is feasible. On the successive MP2RAGE and DTI sequences, we observe a gradual decrease over time in the described ROIs, representing the progressive maturation of the WM micro-structure and interestingly the same evolution is observed in the grey matter. We speculate that our study will provide normative values for T1map and ADC and might be a predictive factor for favourable or less favourable outcome.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

OBJECTIVES: To determine characteristics associated with single and multiple fallers during postacute rehabilitation and to investigate the relationship among falls, rehabilitation outcomes, and health services use. DESIGN: Retrospective cohort study. SETTING: Geriatric postacute rehabilitation hospital. PARTICIPANTS: Patients (n = 4026) consecutively admitted over a 5-year period (2003-2007). MEASUREMENTS: All falls during hospitalization were prospectively recorded. Collected patients' characteristics included health, functional, cognitive, and affective status data. Length of stay and discharge destination were retrieved from the administrative database. RESULTS: During rehabilitation stay, 11.4% (458/4026) of patients fell once and an additional 6.3% (253/4026) fell several times. Compared with nonfallers, fallers were older and more frequently men. They were globally frailer, with lower Barthel score and more comorbidities, cognitive impairment, and depressive symptoms. In multivariate analyses, compared with 1-time fallers, multiple fallers were more likely to have lower Barthel score (adjOR: 2.45, 95% CI: 1.48-4.07; P = .001), cognitive impairment (adjOR: 1.43, 95% CI: 1.04-1.96; P = .026), and to have been admitted from a medicine ward (adjOR: 1.55, 95% CI: 1.03-2.32; P = .035). Odds of poor functional recovery and institutionalization at discharge, as well as length of stay, increased incrementally from nonfallers to 1-time and to multiple fallers. CONCLUSION: In these patients admitted to postacute rehabilitation, the proportion of fallers and multiple fallers was high. Multiple fallers were particularly at risk of poor functional recovery and increased health services use. Specific fall prevention programs targeting high-risk patients with cognitive impairment and low functional status should be developed in further studies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

An overview of ocular implants with therapeutic application potentials is provided. Various types of implants can be used as slow release devices delivering locally the needed drug for an extended period of time. Thus, multiple periocular or intraocular injections of the drug can be circumvented and secondary complications minimized. The various compositions of polymers fulfilling specific delivery goals are described. Several of these implants are undergoing clinical trials while a few are already commercialized. Despite the paramount progress in design, safety and efficacy, the place of these implants in our clinical therapeutic arsenal remains limited. Miniaturization of the implants allowing for their direct injection without the need for a complicated surgery is a necessary development avenue. Particulate systems which can be engineered to target specifically certain cells or tissues are another promising alternative. For ocular diseases affecting the choroid and outer retina, transscleral or intrasscleral implants are gaining momentum.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In numerical linear algebra, students encounter earlythe iterative power method, which finds eigenvectors of a matrixfrom an arbitrary starting point through repeated normalizationand multiplications by the matrix itself. In practice, more sophisticatedmethods are used nowadays, threatening to make the powermethod a historical and pedagogic footnote. However, in the contextof communication over a time-division duplex (TDD) multipleinputmultiple-output (MIMO) channel, the power method takes aspecial position. It can be viewed as an intrinsic part of the uplinkand downlink communication switching, enabling estimationof the eigenmodes of the channel without extra overhead. Generalizingthe method to vector subspaces, communication in thesubspaces with the best receive and transmit signal-to-noise ratio(SNR) is made possible. In exploring this intrinsic subspace convergence(ISC), we show that several published and new schemes canbe cast into a common framework where all members benefit fromthe ISC.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Diplomityössä perehdytään UMTS-verkon historiaan, monikäyttötekniikkaan ja suun-nitteluun. Erityisesti tarkastellaan UMTS-verkon palveluiden laatuvaatimuksia (QoS), joiden avulla sekä palveluiden käyttäjät että palveluiden tarjoajat voivat käyttää radiora-japintaa haluamallaan tavalla. Käytännön osassa tarkastellaan QoS:ien mukaisia palveluita, palveluiden sijoittamista UMTS-verkkoon ja palvelutuotantoon liittyviä teknisiä rajoituksia. Lisäksi tarkastel-laan, miten UMTS-verkossa olevan päätelaitteen dataliikenteen taajuuskaista muuttuu päätelaitteen liikkuessa.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The advent of simple and affordable tools for molecular identification of novel insect invaders and assessment of population diversity has changed the face of invasion biology in recent years. The widespread application of these tools has brought with it an emerging understanding that patterns in biogeography, introduction history and subsequent movement and spread of many invasive alien insects are far more complex than previously thought. We reviewed the literature and found that for a number of invasive insects, there is strong and growing evidence that multiple introductions, complex global movement, and population admixture in the invaded range are commonplace. Additionally, historical paradigms related to species and strain identities and origins of common invaders are in many cases being challenged. This has major consequences for our understanding of basic biology and ecology of invasive insects and impacts quarantine, management and biocontrol programs. In addition, we found that founder effects rarely limit fitness in invasive insects and may benefit populations (by purging harmful alleles or increasing additive genetic variance). Also, while phenotypic plasticity appears important post-establishment, genetic diversity in invasive insects is often higher than expected and increases over time via multiple introductions. Further, connectivity among disjunct regions of global invasive ranges is generally far higher than expected and is often asymmetric, with some populations contributing disproportionately to global spread. We argue that the role of connectivity in driving the ecology and evolution of introduced species with multiple invasive ranges has been historically underestimated and that such species are often best understood in a global context.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Terveydenhuollon ja siihen liittyvien palvelujen kustannusten jatkuva kohoaminen ja kuntien paheneva taloustilanne sekä terveydenhuollon pienenevät henkilöstöresurssit ovat lisänneet painetta toimintojen kustannustehokkaaseen toteuttamiseen. Edellä mainitusta johtuen, terveydenhuollon toimijoita kehotetaan etsimään uusia ratkaisuja, joilla voidaan taata jatkossa riittävä asiakaspalvelutaso, kustannustehokkuus ja – palvelujen turvallisuus. Tämän työn tavoitteena oli vastata kysymyksiin tunnistus- ja paikannustoiminnan hyödyntämisen mahdollisuuksista Itä-Savon sairaanhoitopiirin Savonlinnan keskussairaalassa. Tarkoituksena oli selvittää, millaisia paikannus ja tunnistusteknologiaan liittyviä tavoitteita ja vaatimuksia terveydenhuollon toimialalla ja erityisesti Itä-Savon sairaanhoitopiirissä on ja millä tavalla RFID ja WLAN – teknologioilla saadaan kehitettyä asetettuihin tavoitteisiin ja hyötyodotuksiin vastaavat ratkaisut. Työssä pyrittiin selvittämään myös millaisia rahallisia säästöjä tunnistus- ja paikannusteknologioilla voidaan saada aikaan. Työn yhteydessä kartoitettiin tarpeita ja vaatimuksia tunnistus- ja paikannusteknologian hyödyntämiseen. Tarpeet ja vaatimukset testattiin tunnistus- ja paikannuspilotissa. Lisäksi perehdyttiin kirjallisuuteen ja aiempiin tutkimuksiin tunnistus- ja paikannusteknologioista. Suunnitelman perusteella näyttää siltä, että hyödyntämällä tunnistus- ja paikannusteknologioita voitaisiin tehostaa Savonlinnan keskussairaalan toimintaa. Suunnitelman pilottivaiheen tuloksien perusteella toiminnan tehostaminen tarkoittaisi kustannussäästöjä, parantaisi potilasturvallisuutta sekä hoitotyön laatua. Tunnistus- ja paikannusteknologian käyttökohteita sairaalassa voisivat olla esimerkiksi reaaliaikaiseen prosessien ohjaaminen, kulunvalvonnan ja -ohjauksen automatisointi, potilaan automaattinen tunnistaminen, sekä sairaalan tutkimuslaitteiden seuranta.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the last few years, the use of laparoscopy in veterinary medicine has expanded and consequently so was the need for studies that establish the advantages, disadvantages and possible complications of each procedure. The purpose of the current study was to describe a laparoscopic splenectomy technique and the alterations due to this access, and compare it to the open procedure in dogs. A total of 15 healthy female mongrel dogs were used, with mean weight of 17.4±2.5kg. The animals were distributed into three groups: Group IA of open splenectomy (laparotomy) using double ligation of the vessels of the splenic hilum with poliglicolic acid, Group IB of open splenectomy (laparotomy) with bipolar electrocoagulation of the splenic hilum, and Group II of laparoscopic access with bipolar electrocoagulation of the splenic hilum. Operative time, blood loss, size of incisions, complications during and after surgery were evaluated. Other parameters included pain scores, white blood cell (WBC) counts and postoperative serum concentrations of alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), C-reactive protein (CRP), glucose and cortisol. No differences were found in the evaluation of parameters between both open splenectomy techniques employed. Laparoscopic access presented significant differences (p<0,05) when compared with open surgery: Longer operative time, smaller abdominal access, decrease in blood loss, lower concentrations of CRP, higher levels of CK and ALP, and lower scores in the pain scale. Laparoscopic surgery showed fewer complications of the surgical wound. No significant differences were observed between groups in the postoperative temperature, WBC, ALT, cortisol and glucose concentrations. In conclusion, the laparoscopic technique is useful for splenectomy in dogs, being advantageous in terms of blood loss, surgical stress and surgical wounds. However, it expends more operative time and causes transitory increase in hepatic and muscular enzymes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014