Design and capacity performance analysis of wireless mesh network

Proceedings of: 5th International Conference on Mobile Technology, Applications, and Systems (Mobility 2008), (September 10-12, 2008), Yilan (Taiwan)From the network operator’s point of view, the high CAPEX/OPEX cost resulting from fixed/wired backhaul links can be inhibitive to successful deployment of broadband wireless services. The emerging wireless mesh network (WMN) technology is seen as one of the potential solutions which may reduce wired backhaul dependency through multihop transmission. Despite the advantages, many remain sceptical on WMN’s network capacity and scalability performances particularly when the user density is high. This paper provides an insight on the best possible upper-bound capacity performance of WMN, taking into consideration three key design parameters namely 1) Percentage of wired backhaul points per network, 2) Mesh-to-Access Link-Rate Ratio (R) and 3) Number of radio interfaces per mesh node including hybrid radio options. These design options are compared and contrasted with different deployment densities. The results generally show that the higher the number of backhaul points, the higher the effective access capacity available to mesh node and hence user domain. Increasing the R and the number of radio per mesh node are two alternative means to push up the effective access capacity per mesh node without increasing the number of wired backhaul points. This is most significant in multi radio system where about 80% of the backhaul points can be eliminated with R= 3 in order to maintain effective access capacity close to full rate (Capacity, C=1) per mesh node. It is also found that 50% of the backhaul points can be eliminated with R=2 for all radio options (except for the pure single radio case).European Community's Seventh Framework ProgramThis work was partially funded by the European Commission within the 7th Framework Program in the context of the ICT project CARMEN (Grant Agreement No. 214994) http://www.ict-carmen.eu

Development of Novel Primers and Probes Based on its 2 Region Using Nested-PCR and DNA Hybridization Array for Candida Species Identification

Sensitivity, specificity, simplicity, speed, and economy fairly well describe the desirable attributes of any clinical diagnostic test. In the mycology laboratory, the detection and differentiation of Candida species usually rely on the morphological, physiological, and biochemical characteristics which are complex, frequently slow to appear, sometimes vary within a species, and usually require significant experience to evaluate. In this study, novel primers and probes had been developed for the identification of 8 Candida species using nested-PCR and DNA hybridization array by focusing on a single parameter. This parameter is the identification of nucleotide sequence from ITS 2 region that is known to be unique for the Candida species. These distinctive sequences were used to design and develop Candida species-specific primers and probes for nested-PCR and DNA hybridization array, respectively. For nested-PCR, the universal fungal primers, ITS 3 and ITS 4 were used to amplify the portion of the 5.8S and 28S rDNA, and the ITS 2 region of Candida species. The amplicons were used as template together with developed species-specific primers in the subsequent amplification. The results were analyzed using agarose gel electrophoresis. In addition, species-specific probes were used to hybridize to the biotinylated Candida species ITS 2 amplicons via DNA hybridization array. The amplicons were detected colorimetrically in strip format. The sensitivity and specificity of the Candida species-specific primers and probes were evaluated. The 8 Candida ATCC strains and 24 clinical isolates did not exhibit cross-priming and cross-hybridization with the species-specific primers and probes in both assays and all the Candida species were correctly identified. In simulated clinical specimens, the sensitivity of the nested-PCR for Candida species detection was 10 cells/mL. However, the detection limit for both PCR using species-specific primers and DNA hybridization array using species-specific probes for the detection of Candida culture DNA was 1-10 cells/mL. Additionally, a preliminary study was done for the screening of 40 healthy donors’ sera using the real-time PCR for the detection of Candida albicans using species-specific primers, CAL1 and CAL3. The melting curve was used for the analyses of the results. 3 out of 40 samples were found to be positive for Candida albicans. It is suggested that the real-time PCR may not be able to distinguish the individuals who are colonized from those who are infected.\ud In conclusion, the nested-PCR and DNA hybridization array using the developed species-specific primers and probes, respectively, in this study are robust, sensitive and can be easily integrated into a clinical diagnostic laboratory with the potential for same-day diagnosis of Candida infection. In addition, the simultaneous differentiation of Candida species via DNA hybridization array allows faster and simpler diagnosis compare to nested-PCR. For real-time PCR screening of the healthy donors’ sera, further evaluation needs to be done to determine a threshold as standard guideline to detect the infectious and colonized Candida albicans and non-albicans Candida species

Deployment analysis of carrier grade urban wireless mesh networks

Proceedings of: IEEE 9th Malaysia International Conference on Communications (MICC 2009), 15-17 December 2009, Kuala Lumpur (Malaysia)An optimized and cost-effective wireless mesh network (WMN) deployment for ubiquitous broadband wireless access is known to be highly dependent on a number of key factors such as backhaul solution, number of radio interfaces per node, type of radio technology, network topology/cluster, etc. The choice of network topology in turn affects the gateway-node ratio, and also the placement of gateways (GW)s and access points (AP)s. In this paper, we provide insights on the best possible upper-bound performance and inter-relationship between these key design factors under different operating conditions with respect to different target data rates per user. Next, we incorporate deployment cost analysis into the corresponding design option studies in order to provide more accurate justification on the feasibility of adopting different clustering techniques. The results from our analysis offer a general guideline or reference for network operators who intend to deploy a uniform blanket coverage using WMN especially in the urban environment.European Community's Seventh Framework ProgramPublicad

A cost sensitiviy analysis for carrier grade wireless mesh networks with tabu optimization

Proceedings of: CARMEN 2010: 2nd International Workshop on CARrier-grade wireless MEsh Networks in conjunction with IEEE INFOCOM 2010: IEEE Conference on Computer Communications Workshops: 15-19 March 2010, San Diego, CaliforniaWe present an insight on the sensitivity of total cost (CAPEX+OPEX) towards various key input parameters for CARrier Grade Wireless MEsh Networks (CARMEN) deployment These input parameters span across three main categories namely the network design options, environment conditions and cost. Various boundary conditions are imposed to allow network operator to understand the impacts of parameters'changes with the highest level of uncertainty. A simple Tabu optimization method is adopted to optimize the node density against target data rate and range.European Community's Seventh Framework ProgramPublicad

Trato digno y satisfacción del usuario externo de psiquiatría del Hospital Hermilio Valdizán, Santa Anita, 2018

El objetivo de esta investigación fue determinar la relación entre el trato digno y la satisfacción del usuario externo de psiquiatría del Hospital Hermilio Valdizán, Santa Anita, 2018. En cuanto a la metodología, esta investigación se desarrolló respetando todo el proceso del enfoque cuantitativo, manejo del diseño no experimental, el método fue el hipotético - deductivo, tipo de estudio descriptivo correlacional de corte transversal. La población del estudio fue constituida por los usuarios externos de psiquiatría del Hospital Hermilio Valdizán, Santa Anita, 2018 en un total de 657, de donde se tomó una muestra significativa de 234 pacientes a través del muestreo probabilístico al 95%. Para recolección de datos se utilizó la técnica denominada encuesta; y los instrumentos utilizados fueron cuestionarios con escalamiento Likert, validados oportunamente y con una fiabilidad muy alta a través de la prueba piloto con el Alfa de Cronbach. Los resultados han evidenciado que, el trato digno al usuario externo de psiquiatría del Hospital Hermilio Valdizán, Santa Anita, 2018, es para el 9,9% “deficiente”, el 45,3%, “regular” y el 44,9%, “eficiente”; y sobre la sat isfacción del usuario externo de psiquiatría, manifestaron: el 39,9% “regularmente satisfechos”, el 55,1%, “sat isfechos” y el 4,9%, “muy sat isfechos”. Las conclusiones fueron los hallazgos de una correlación positiva alta y significativa entre el trato digno y la satisfacción del usuario externo de psiquiatría del Hospital Hermilio Valdizán, Santa Anita, 2018, siendo el Rho de 0,870**; es decir, el índice de correlación fue al 87.0%. Confirmándose a mayor trato digno, mayor satisfacción del usuario externo

Monitoring system for carrier grade mesh networks

Proceedings of: 2010 Future Network & Mobile Summit, 16 - 18 June 2010, Florence, ItalyThe paper presents a monitoring system for carrier grade mesh networks. First, the system architecture, components and interfaces are described. Then the measured and discovered network parameters are discussed. A link prediction and trigger algorithm based on a modified meanreverting diffusion process is proposed. The results from analysis show that this function can significantly enhance link reliability.European Community's Seventh Framework ProgramPublicad

Topologies of wireless mesh networks with inband backhauling

Proceedings of: PIMRC 2010: 21st Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications took place from 26-30 Sep. 2010 in Istanbul, TurkeyWireless mesh networks (WMNs) with in band backhauling use the same antennas for the backhaul as well as for the access. Therefore antennas of next hop neighbours need to be directed to each other. However, such a configuration is not possible in a three-sectorized hexagonal cell deployment. In this paper we derive several alternative topologies that are suitable for WMNs with in band backhauling. We show that a topology with four directional antennas per node and backhaul connectivity between indirect neighbours outperforms competing topologies in terms of handover rate, optimal maximum power, and system capacity.European Community's Seventh Framework ProgramPublicad

Elastic fair rate allocation scheme for multi-radio wireless mesh networks

Fair bandwidth distribution among users remains a persistence issue in Wireless Mesh Networks (WMNs). Users which are more hops away from the gateway generally suffer from higher throughput degradation and hence higher delay. This is mainly due to the nature of IEEE 802.11 protocol, i.e. its operation in contention mode. In this paper, we propose a practical network-layer solution to address this fairness issue in Multi-Radio WMNs. The proposed framework consists of two main components: 1) lightweight messaging system and 2) Elastic fair Rate Allocation Scheme for Mesh Stations (ERASMeS). A highlight of the proposed solution is that it does not require any alteration of existing MAC and routing mechanisms and can be applied to nodes with multiple radio interfaces. This capability distinguishes it from other similar work on fairness provisioning in WMNs. The results obtained from our test-bed show that the proposed solution achieves a high degree of improvement in terms of end-to-end throughput and fairness index for all users

Supporting Carrier Grade Services over Wireless Mesh Networks: the approach of the European FP-7 STREP CARMEN

CARMEN is a three-year Specific Targeted Research Project (STREP) funded by the European Commission within the 7th Framework Program. The CARMEN access network will complement existing access technologies by exploiting low cost mesh networking techniques, thus minimizing deployment and maintenance costs. The CARMEN architecture introduces an abstraction layer that hides the specifics of the underlying access technology providing an abstract interface on top of which higher layers can be easily developed. This allows for the integration of current and future heterogeneous wireless technologies to provide scalable and efficient mobile ubiquitous Internet access, able to adapt to different environments and user requirements. Following these goals, CARMEN aims to define, study and implement link and technology abstractions, mobility support, and quality of service. The architecture also includes advanced monitoring features that allow for dynamic self-configuration, thereby reducing the installation and operational costs.European Community's Seventh Framework ProgramPublicad