341 research outputs found

    Experimental analysis of single and multiple antenna units in uplink of radio-over-fiber distributed antenna system

    Get PDF
    Increasing the number of antennas either at the transmitter or receiver has been shown to improve system reliability without occupying additional spectrum. In this paper, we experimentally investigate the error vector magnitude (EVM) of single and multiple remote antenna units (RAU) focusing on uplink transmission. We demonstrate that for 64-QAM modulation, the EVM requirement of 6.5% could be achieved with multiple separated RAUs in situations where a single RAU fails to meet this requirement. The EVM result was obtained as the transmitting device was placed at different locations in a typical office environment with OFDM signals gathered through the RAUs and brought back to a central unit for processing. The EVM results show that using multiple RAUs and an efficient signal combining technique, here, maximal ratio combining (MRC), the EVM performance could reduce by approximately 2% when the distance between the RAUs was 0.3m and further reduced by 4% and 6% when the inter-RAU distance was 2m and 4m, respectively, compared to a single RAU

    Particulate matter and airborne fungi concentrations in schools in Athens

    Get PDF
    Indoor Air Quality degradation is of exceptional concern due to the potential adverse effects indoor air pollutants have on human’s health. Students are a susceptible group of people, who spend a lot of their time within classrooms. The purpose of this study is to investigate the concentration levels of particulate matter (PM) and total airborne fungi, in school classrooms. Further objective is to examine possible correlations between PM10, PM2.5, PM1, ultrafine particles (UFPs, diameter< 100 nm), and airborne fungi. The measurements were performed using fully automated instrumentation. The results indicate that a lot of PM10 concentrations exceeded the proposed daily limit of 50μg/m3. Also, in some cases the concentration of the total airborne fungi indoors, exceeded their concentration outdoors. There is evidence that certain correlations exist between PM and airborne fungi

    Particulate matter and airborne fungi concentrations in schools in Athens

    Get PDF
    Indoor Air Quality degradation is of exceptional concern due to the potential adverse effects indoor air pollutants have on human’s health. Students are a susceptible group of people, who spend a lot of their time within classrooms. The purpose of this study is to investigate the concentration levels of particulate matter (PM) and total airborne fungi, in school classrooms. Further objective is to examine possible correlations between PM10, PM2.5, PM1, ultrafine particles (UFPs, diameter<100 nm), and airborne fungi. The measurements were performed using fully automated instrumentation. The results indicate that a lot of PM10 concentrations exceeded the proposed daily limit of 50μg/m3. Also, in some cases the concentration of the total airborne fungi indoors, exceeded their concentration outdoors. There is evidence that certain correlations exist between PM and airborne fungi

    Indoor and outdoor distribution of airborne pollutants in naturally ventilated classrooms

    Get PDF
    The present study aims at investigating concentration levels of particulate matter PM10, PM2.5, PM1 and UFP as well as of total airborne fungi and their vertical distribution in the indoor and outdoor environment of school classrooms. Measurements were performed in two naturally ventilated high schools in Athens, from January until May 2011. Indoor concentrations of the pollutants will be presented per floor level and indoor to outdoor (I/O) concentration ratios will be estimated as a function of the floor height. The ultimate goal is to create variations’ profile of I/O pollutant ratios, so as to understand the contribution of indoor sources and the extent to which the indoor air quality is being affected by the outdoor pollutants

    Designing normative open virtual enterprises

    Full text link
    This is an Accepted Manuscript of an article published by Taylor & Francis Group in Enterprise Information Systems on 23/03/2016, available online: http://www.tandfonline.com/10.1080/17517575.2015.1036927.[EN] There is an increasing interest on developing virtual enterprises in order to deal with the globalisation of the economy, the rapid growth of information technologies and the increase of competitiveness. In this paper we deal with the development of normative open virtual enterprises (NOVEs). They are systems with a global objective that are composed of a set of heterogeneous entities and enterprises that exchange services following a specific normative context. In order to analyse and design systems of this kind the multi-agent paradigm seems suitable because it offers a specific solution for supporting the social and contractual relationships between enterprises and for formalising their business processes. This paper presents how the Regulated Open Multiagent systems (ROMAS) methodology, an agent-oriented software methodology, can be used to analyse and design NOVEs. ROMAS offers a complete development process that allows identifying and formalising of the structure of NOVEs, their normative context and the interactions among their members. The use of ROMAS is exemplified by means of a case study that represents an automotive supply chain.This work was partially supported by the projects [PROMETEOII/2013/019], [TIN2012-36586-C03-01], [FP7-29493], [TIN2011-27652-C03-00] and [CSD2007-00022], and the CASES project within the 7th European Community Framework Programme [grant agreement number 294931].Garcia Marques, ME.; Giret Boggino, AS.; Botti Navarro, VJ. (2016). Designing normative open virtual enterprises. Enterprise Information Systems. 10(3):303-324. https://doi.org/10.1080/17517575.2015.1036927S303324103Cardoso, H. L., Urbano, J., Brandão, P., Rocha, A. P., & Oliveira, E. (2012). ANTE: Agreement Negotiation in Normative and Trust-Enabled Environments. Advances on Practical Applications of Agents and Multi-Agent Systems, 261-264. doi:10.1007/978-3-642-28786-2_33Chu, X. N., Tso, S. K., Zhang, W. J., & Li, Q. (2002). Partnership Synthesis for Virtual Enterprises. The International Journal of Advanced Manufacturing Technology, 19(5), 384-391. doi:10.1007/s001700200028Davidsson, P., & Jacobsson, A. (s. f.). Towards Norm-Governed Behavior in Virtual Enterprises. Studies in Computational Intelligence, 35-55. doi:10.1007/978-3-540-88071-4_3DeLoach, S. A., & Ojeda, J. C. G. (2010). O-MaSE: a customisable approach to designing and building complex, adaptive multi-agent systems. International Journal of Agent-Oriented Software Engineering, 4(3), 244. doi:10.1504/ijaose.2010.036984DI MARZO SERUGENDO, G., GLEIZES, M.-P., & KARAGEORGOS, A. (2005). Self-organization in multi-agent systems. The Knowledge Engineering Review, 20(2), 165-189. doi:10.1017/s0269888905000494Dignum, V. 2003. “A Model for Organizational Interaction: Based on Agents, Founded in Logic.” PhD diss., Utrecht University.Dignum, V., and F. Dignum. 2006.A Landscape of Agent Systems for the Real World. Technical Report 44-CS-2006-061. Utrecht: Institute of Information and Computing Sciences, Utrecht University.Dignum, V., Meyer, J.-J. C., Dignum, F., & Weigand, H. (2003). Formal Specification of Interaction in Agent Societies. Lecture Notes in Computer Science, 37-52. doi:10.1007/978-3-540-45133-4_4Garcia, E. 2013. “Engineering Regulated Open Multiagent Systems.” PhD diss., Universitat Politecnica de Valencia.Garcia, E., Giret, A., & Botti, V. (s. f.). Software Engineering for Service-Oriented MAS. Lecture Notes in Computer Science, 86-100. doi:10.1007/978-3-540-85834-8_9Garcia, E., Giret, A., & Botti, V. (2013). A Model-Driven CASE tool for developing and verifying regulated open MAS. Science of Computer Programming, 78(6), 695-704. doi:10.1016/j.scico.2011.10.009Garcia, E., Giret, A., & Botti, V. (2011). Evaluating software engineering techniques for developing complex systems with multiagent approaches. Information and Software Technology, 53(5), 494-506. doi:10.1016/j.infsof.2010.12.012Garcia, E., Giret, A., & Botti, V. (2011). Regulated Open Multi-Agent Systems Based on Contracts. Information Systems Development, 243-255. doi:10.1007/978-1-4419-9790-6_20Garcia, E., Giret, A., & Botti, V. (2014). ROMAS Methodology. Handbook on Agent-Oriented Design Processes, 331-369. doi:10.1007/978-3-642-39975-6_11Hollander, C. D., & Wu, A. S. (2011). The Current State of Normative Agent-Based Systems. Journal of Artificial Societies and Social Simulation, 14(2). doi:10.18564/jasss.1750HORLING, B., & LESSER, V. (2004). A survey of multi-agent organizational paradigms. The Knowledge Engineering Review, 19(4), 281-316. doi:10.1017/s0269888905000317Julian, V., Rebollo, M., Argente, E., Botti, V., Carrascosa, C., & Giret, A. (2009). Using THOMAS for Service Oriented Open MAS. Lecture Notes in Computer Science, 56-70. doi:10.1007/978-3-642-10739-9_5Luck, M., Barakat, L., Keppens, J., Mahmoud, S., Miles, S., Oren, N., … Taweel, A. (2011). Flexible Behaviour Regulation in Agent Based Systems. Lecture Notes in Computer Science, 99-113. doi:10.1007/978-3-642-22427-0_8Meneguzzi, F., Modgil, S., Oren, N., Miles, S., Luck, M., & Faci, N. (2012). Applying electronic contracting to the aerospace aftercare domain. Engineering Applications of Artificial Intelligence, 25(7), 1471-1487. doi:10.1016/j.engappai.2012.06.004Presley, A., Sarkis, J., Barnett, W., & Liles, D. (2001). International Journal of Flexible Manufacturing Systems, 13(2), 145-162. doi:10.1023/a:1011131417956Saeki, M., & Kaiya, H. (2008). Supporting the Elicitation of Requirements Compliant with Regulations. Active Flow and Combustion Control 2018, 228-242. doi:10.1007/978-3-540-69534-9_18Such, J. M., García-Fornes, A., Espinosa, A., & Bellver, J. (2013). Magentix2: A privacy-enhancing Agent Platform. Engineering Applications of Artificial Intelligence, 26(1), 96-109. doi:10.1016/j.engappai.2012.06.009Telang, P. R., & Singh, M. P. (2009). Enhancing Tropos with Commitments. Lecture Notes in Computer Science, 417-435. doi:10.1007/978-3-642-02463-4_22Wooldridgey, M., & Ciancarini, P. (2001). Agent-Oriented Software Engineering: The State of the Art. Lecture Notes in Computer Science, 1-28. doi:10.1007/3-540-44564-1_

    Support of Multi-antenna and Multi-user Systems Using Radio Over Fiber

    Get PDF
    Analog radio-over-fiber can efficiently support multi-antenna and multi-user techniques for future mobile communications. Experimental results demonstrate that the wider antenna separation that can be provided enhances multi-antenna scheme performance

    Sirenomelia in a Nigerian triplet: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Sirenomelia, also known as mermaid syndrome, is a very rare fatal congenital abnormality in which the legs are fused together, giving them the appearance of a mermaid's tail. It is commonly associated with abnormal kidney development, genital and rectal abnormalities. A handful of cases have been reported in other parts of the world, however, no cases have previously been reported in a Nigerian neonate. To the best of our knowledge, we believe that this is the first case reported from West Africa and in a triplet.</p> <p>Case presentation</p> <p>A 16-hour-old baby boy, the second of a set of Nigerian triplets, presented to our facility with fusion of the entire lower limbs, imperforate anus, indiscernible genital structures, single umbilical artery and a neural tube defect. His parents were from the Hausa ethnic group and not related.</p> <p>Conclusion</p> <p>Sirenomelia has not been previously described in a set of triplets, and it is hoped that this report from West Africa will give information about the non-racial predilection of this condition.</p
    corecore