Search results for "Node"
showing 10 items of 1701 documents
A feasibility analysis on the use of ultrasonic multihop communications for E-health applications
2017
Rise in population aging as well as diffusion of chronic diseases and health consciousness require constant monitoring of health conditions but also lead to increasing costs for the governments. Body Area Networks represent the next frontier in health care and are envisaged as the natural choice to provide detailed and updated information on health status to prevent health risks and diseases. However if, on the one hand, a large research effort has been devoted so far to the investigation of BAN communications on and around the body, on the other hand intra-BAN communications are still a scarcely explored area because of the difficulties and risks in successfully propagating signals inside …
On the Benefits of Random Linear Coding for Unicast Applications in Disruption Tolerant Networks
2006
In this paper, we investigate the benefits of using a form of network coding known as Random Linear Coding (RLC) for unicast communications in a mobile Disruption Tolerant Network (DTN) under epidemic routing. Under RLC, DTN nodes store and then forward random linear combinations of packets as they encounter other DTN nodes. We first consider the case where there is a single block of packets propagating in the network and then consider the case where blocks of K packets arrive according to a Poisson arrival process. Our performance metric of interest is the delay until the last packet in a block is delivered. We show that for the single block case, when bandwidth is constrained, applying RL…
An optimal energy efficient cooperative retransmission MAC scheme in wireless networks
2011
While the benefits of cooperative diversity have been well studied in the literature, cooperative MAC protocol design has also attracted much attention recently. In the single-relay Cooperative Automatic Repeat reQuest (C-ARQ) protocol, the best relay node is selected in a distributed manner by relays using different backoff time before packet retransmission. However, this relay selection scheme does not work efficiently in a dense network scenario, due to possible high collision probability among different contending relays. In this paper, we propose an optimized relay selection scheme to maximize system energy efficiency by reducing collision probability. The energy efficiency performance…
HSDPA Link Adaptation Improvement Based on Node-B CQI Processing
2007
In this paper HSDPA link adaptation (LA) based on Channel Quality Indicator (CQI) reports is optimised. A pre-processing of the last received CQI reports is done before the execution of the LA algorithm in the Node-B in order to obtain more profitable channel quality estimations and hence improve the LA performance. Different types of processing techniques are presented and assessed, considering from the simplest sample averaging to some more elaborated predictive algorithms. Results demonstrate that a non negligible enhancement in the LA performance can be obtained if medium and high speed users are considered.
The Level of Cytokeratin 18 in Patients with HIV and Viral Hepatitis C Co-Infection in Latvia
2020
Abstract Cytokeratin 18 (CK18) is a specific marker of hepatocellular apoptosis, which is a useful noninvasive indicator of liver fibrosis in the HIV/HCV group. However, data on the CK18 level in serum are limited for this group. This study demonstrated CK18 levels in serum in HIV/HCV co-infected and HIV mono-infected patients; investigated the association of CK18 levels with other non-invasive markers of liver fibrosis; and presents CK18 dynamics in a four-month-long period. The sample included 273 patients with HIV infection (128 of them were with HIV/HCV co-infection) aged from 23 to 65 (35% females). Levels of hyaluronic acid, CK18, ALT, and AST were determined in serum, and the FIB4 in…
Thymic transplantation for relief of immunodeficiency diseases.
1979
Tremendous advances have been made in replacement therapy regimens for the correction of immunodeficiency in transplant patients. Recently, cultured thymic fragments were shown to be devoid of lethal graft-versus-host cells and research in this area indicates that thymic transplantation may have a sustained positive effect in immunosuppressed patients.
Graft-Versus-Host Disease or Infection: Rapid Detection of HLA Mismatch-Reactive T Cells Ex Vivo Can Facilitate Diagnosis and Guide Therapy after All…
2007
Abstract Diagnosis of graft-versus-host disease (GVHD) is mainly based on clinical features and on tissue biopsies. However, clinicians and pathologists are well aware of cases, in which GVHD cannot be distinguished from infections arising from severe immunodeficiency after allogeneic stem-cell transplantation (SCT). This may pose a deep therapeutic dilemma of whether to modify immunosuppressive treatment or to use donor lymphocyte infusion (DLI) for promoting anti-microbial immunity. We observed a 68-year-old patient with myelodysplastic syndrome who developed acute GVHD grade II of skin and gut at d+16 after T-cell depleted reduced-intensity SCT (Fig. 1). GVHD was confirmed by histology a…
HIV Infection in 403 Female Prostitutes in Italy
1991
Since the beginning of HIV epidemic, it became clear that the modality of transmission was different between Western Countries and Africa (1). Infact, in Africa heterosexual contact is the most important factor in the spread of HIV infection and female prostitutes are considered to be the major reservoir of HIVinfection (2).
Performance evaluation of a measurement-based algorithm for distributed admission control in a DiffServ framework
2002
Distributed Admission Control in IP DiffServ environments is an emerging and promising research area. Distributed admission control solutions share the idea that no coordination among network routers (i.e. explicit signaling) is necessary, when the decision whether to admit or reject a new offered flow is pushed to the edge of the IP network. Proposed solutions differ in the degree of complexity required in internal network routers, and result in a different robustness and effectiveness in controlling the accepted traffic. This paper builds on a recently proposed distributed admission control solution, called GRIP (Gauge&Gate Reservation with Independent Probing), designed to integrate the …
A Multi-Relay Cooperative Automatic Repeat Request Protocol in Wireless Networks
2010
This paper proposes a Multi-relay Cooperative Automatic Repeat ReQuest protocol (MC-ARQ) for IEEE 802.11 based wireless networks. The proposed distributed relay selection scheme not only selects the best relays but also solves the collision problem among multiple contending relays, by sorting the relays in the network according to their instantaneous channel quality with the destination node. No prior information or explicit signaling among relay nodes is required. Both analytical and simulation results show that significant benefits can be achieved with the MC-ARQ protocol, compared with both the recently proposed PRCSMA scheme and the original non-cooperative DCF scheme.