348 research outputs found
Characteristics of chicken slaughterhouse wastewater
The chicken slaughterhouse wastewater is a class of wastewater, which is heavily polluted with organic matters including proteins, blood residues, fats and lard. Therefore, the direct discharged of untreated chicken slaughterhouse wastewater into the environment is associated with the occurrence of eutrophication phenomenon. In the present study, the characteristics of chicken slaughterhouse wastewater were investigated to ascertain the role of these wastes in the adverse effect on the environment and natural water system. The parameter tested included biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), total nitrogen (TN), total organic carbon (TOC), orthophosphate (PO4 3-), temperature and pH. The results revealed available high concentrations of BOD (1,341 - 1,821 ± 242.7 mg L1 ), COD (3,154.19 - 7,719.3 ± 2,282.69 mg L-1), TSS (377.67 - 5,462 ± 2,696.1 mg L-1) which have exceeded the EQA1974 standard limits for disposal of wastewater into the environment. The concentrations of TN (162.6 -563.8 ± 215 mg L-1) and PO4 3- (7.047 - 17.111 ± 4.25 mg L-1) were within the range required for microalgae growth which confirm their role in the occurrence of eutrophication phenomenon. It can be concluded that the direct discharge of chicken slaughterhouse wastewater contributes negatively on the environmental biodiversity and thus they should be subjected for an effective treated before the final disposal
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Application priority framework for fixed mobile converged communication networks
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The current prospects in wired and wireless access networks, it is becoming increasingly important to address potential convergence in order to offer integrated broadband services. These systems will need to offer higher data transmission capacities and long battery life, which is the catalyst for an everincreasing variety of air interface technologies targeting local area to wide area connectivity. Current integrated industrial networks do not offer application aware context delivery and enhanced services for optimised networks. Application aware services provide value-added functionality to business applications by capturing, integrating, and consolidating intelligence about users and their endpoint devices from various points in the network. This thesis mainly intends to resolve the issues related to ubiquitous application aware service, fair allocation of radio access, reduced energy consumption and improved capacity. A technique that measures and evaluates the data rate demand to reduce application response time and queuing delay for multi radio interfaces is proposed. The technique overcomes the challenges of network integration, requiring no user intervention, saving battery life and selecting the radio access connection for the application requested by the end user. This study is split in two parts. The first contribution identifies some constraints of the services towards the application layer in terms of e.g. data rate and signal strength. The objectives are achieved by application controlled handover (ACH) mechanism in order to maintain acceptable data rate for real-time application services. It also looks into the impact of the radio link on the application and identifies elements and parameters like wireless link quality and handover that will influence the application type. It also identifies some enhanced traditional mechanisms such as distance controlled multihop and mesh topology required in order to support energy efficient multimedia applications. The second contribution unfolds an intelligent application priority assignment mechanism (IAPAM) for medical applications using wireless sensor networks. IAPAM proposes and evaluates a technique based on prioritising multiple virtual queues for the critical nature of medical data to improve instant transmission. Various mobility patterns (directed, controlled and random waypoint) has been investigated and compared by simulating IAPAM enabled mobile BWSN. The following topics have been studied, modelled, simulated and discussed in this thesis: 1. Application Controlled Handover (ACH) for multi radios over fibre 2. Power Controlled Scheme for mesh multi radios over fibre using ACH 3. IAPAM for Biomedical Wireless Sensor Networks (BWSN) and impact of mobility over IAPAM enabled BWSN. Extensive simulation studies are performed to analyze and to evaluate the proposed techniques. Simulation results demonstrate significant improvements in multi radios over fibre performance in terms of application response delay and power consumption by upto 75% and 15 % respectively, reduction in traffic loss by upto 53% and reduction in delay for real time application by more than 25% in some cases
Radio Communications
In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modiïŹed our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the ïŹeld of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks
Design and Analysis of Medium Access Control Protocols for Broadband Wireless Networks
The next-generation wireless networks are expected to integrate diverse network architectures and various wireless access technologies to provide a robust solution for ubiquitous broadband wireless access, such as wireless local area networks (WLANs), Ultra-Wideband (UWB), and millimeter-wave (mmWave) based wireless personal area networks (WPANs), etc. To enhance the spectral efficiency and link reliability, smart antenna systems have been proposed as a promising candidate for future broadband access networks. To effectively exploit the increased capabilities of the emerging wireless networks, the different network characteristics and the underlying physical layer features need to be considered in the medium access control (MAC) design, which plays a critical role in providing efficient and fair resource sharing among multiple users.
In this thesis, we comprehensively investigate the MAC design in both single- and multi-hop broadband wireless networks, with and without infrastructure support. We first develop mathematical models to identify the performance bottlenecks and constraints in the design and operation of existing MAC. We then use a cross-layer approach to mitigate the identified bottleneck problems. Finally, by evaluating the performance of the proposed protocols with analytical models and extensive simulations, we determine the optimal protocol parameters to maximize the network performance.
In specific, a generic analytical framework is developed for capacity study of an IEEE 802.11 WLAN in support of non-persistent asymmetric traffic flows. The analysis can be applied for effective admission control to guarantee the quality of service (QoS) performance of multimedia applications. As the access point (AP) becomes the bottleneck in an infrastructure based WLAN, we explore the multiple-input multiple-output (MIMO) capability in the future IEEE 802.11n WLANs and propose a MIMO-aware multi-user (MU) MAC. By exploiting the multi-user degree of freedom in a MIMO system to allow the AP to communicate with multiple users in the downlink simultaneously, the proposed MU MAC can minimize the AP-bottleneck effect and significantly improve the network capacity. Other enhanced MAC mechanisms, e.g., frame aggregation and bidirectional transmissions, are also studied.
Furthermore, different from a narrowband system where simultaneous transmissions by nearby neighbors collide with each other, wideband system can support multiple concurrent transmissions if the multi-user interference can be properly managed. Taking advantage of the salient features of UWB and mmWave communications, we propose an exclusive region (ER) based MAC protocol to exploit the spatial multiplexing gain of centralized UWB and mmWave based wireless networks. Moreover, instead of studying the asymptotic capacity bounds of arbitrary networks which may be too loose to be useful in realistic networks, we derive the expected capacity or transport capacity of UWB and mmWave based networks with random topology. The analysis reveals the main factors affecting the network (transport) capacity, and how to determine the best protocol parameters to maximize the network capacity. In addition, due to limited transmission range, multi-hop relay is necessary to extend the communication coverage of UWB networks. A simple, scalable, and distributed UWB MAC protocol is crucial for efficiently utilizing the large bandwidth of UWB channels and enabling numerous new applications cost-effectively. To address this issue, we further design a distributed asynchronous ER based MAC for multi-hop UWB networks and derive the optimal ER size towards the maximum network throughput. The proposed MAC can significantly improve both network throughput and fairness performance, while the throughput and fairness are usually treated as a tradeoff in other MAC protocols
Energy efficiency in short and wide-area IoT technologiesâA survey
In the last years, the Internet of Things (IoT) has emerged as a key application context in the design and evolution of technologies in the transition toward a 5G ecosystem. More and more IoT technologies have entered the market and represent important enablers in the deployment of networks of interconnected devices. As network and spatial device densities grow, energy efficiency and consumption are becoming an important aspect in analyzing the performance and suitability of different technologies. In this framework, this survey presents an extensive review of IoT technologies, including both Low-Power Short-Area Networks (LPSANs) and Low-Power Wide-Area Networks (LPWANs), from the perspective of energy efficiency and power consumption. Existing consumption models and energy efficiency mechanisms are categorized, analyzed and discussed, in order to highlight the main trends proposed in literature and standards toward achieving energy-efficient IoT networks. Current limitations and open challenges are also discussed, aiming at highlighting new possible research directions
Estratégias de design de camada intermédia e cooperativa para redes sem fios energeticamente eficientes
Doutoramento conjunto MAP-i em InformĂĄticaThe promise of a truly mobile experience is to have the freedom to roam
around anywhere and not be bound to a single location. However, the energy
required to keep mobile devices connected to the network over extended
periods of time quickly dissipates. In fact, energy is a critical resource in
the design of wireless networks since wireless devices are usually powered by
batteries. Furthermore, multi-standard mobile devices are allowing users to
enjoy higher data rates with ubiquitous connectivity. However, the bene ts
gained from multiple interfaces come at a cost in terms of energy consumption
having profound e ect on the mobile battery lifetime and standby
time. This concern is rea rmed by the fact that battery lifetime is one of
the top reasons why consumers are deterred from using advanced multimedia
services on their mobile on a frequent basis. In order to secure market
penetration for next generation services energy e ciency needs to be placed
at the forefront of system design. However, despite recent e orts, energy
compliant features in legacy technologies are still in its infancy, and new
disruptive architectures coupled with interdisciplinary design approaches are
required in order to not only promote the energy gain within a single protocol
layer, but to enhance the energy gain from a holistic perspective. A
promising approach is cooperative smart systems, that in addition to exploiting
context information, are entities that are able to form a coalition
and cooperate in order to achieve a common goal. Migrating from this baseline,
this thesis investigates how these technology paradigm can be applied
towards reducing the energy consumption in mobile networks. In addition,
we introduce an additional energy saving dimension by adopting an interlayer
design so that protocol layers are designed to work in synergy with
the host system, rather than independently, for harnessing energy. In this
work, we exploit context information, cooperation and inter-layer design for
developing new energy e cient and technology agnostic building blocks for
mobile networks. These technology enablers include energy e cient node
discovery and short-range cooperation for energy saving in mobile handsets,
complemented by energy-aware smart scheduling for promoting energy saving
on the network side. Analytical and simulations results were obtained,
and veri ed in the lab on a real hardware testbed. Results have shown that
up to 50% energy saving could be obtained.A promessa de uma experiĂȘncia realmente mĂłvel Ă© de ter a liberdade de deambular por qualquer sĂtio e nĂŁo estar preso a um Ășnico local. No entanto, a energia requerida para manter dispositivos mĂłveis conectados Ă rede, num perĂodo extenso de tempo, o mesmo rapidamente se dissipa. Na realidade, a energia Ă© um recurso crĂtico no design de redes sem fios, uma vez que esses dispositivos sĂŁo alimentados por baterias. Para alĂ©m disso, dispositivos mĂłveis multi-standard permitem que os utilizadores desfrutem
de elevadas taxas de dados com conectividade omnipresente. No entanto, as vantagens adquiridas pelas mĂșltiplas interfaces, imputa uma despesa, sendo essa um consumo maior de energia, numa era onde os dispositivos mĂłveis tĂȘm de ser energicamente complacentes. Esta preocupação Ă© reafirmada pelo facto de que a vida da bateria Ă© uma das principais razĂ”es que impede os utilizadores de usufruir e utilizar de serviços de multimĂ©dia mais avançados nos seus dispositivos, numa base frequente. De forma a assegurar a entrada no mercado para serviços da prĂłxima geração, eficiĂȘncia energĂ©tica tem de ser colocada na vanguarda do design de sistemas. No entanto, apesar de esforços recentes, funcionalidades que cumpram os requisitos energĂ©ticos em tecnologias "legacy" ainda estĂŁo nos seus primĂłrdios e novas abordagens disruptivas sĂŁo requeridas, juntamente com abordagem de design interdisciplinar, de forma a aproveitar a poupança energĂ©tica das diversas camadas protocolares. Uma bordagem promissora sĂŁo os sistemas de cooperação inteligente,
que exploram nĂŁo sĂŁo contexto da informação, mas tambĂ©m as entidades que sĂŁo igualmente capazes de formar uma coligação e cooperam de forma a atingir um objectivo comum. Migrar a partir destas referĂȘncias, esta tese investiga como Ă© que este paradigma tecnolĂłgico pode ser aplicado para reduzir a potĂȘncia e consumo de energia em redes mĂłveis. Para alĂ©m disso, introduzimos uma dimensĂŁo de poupança energĂ©tica adicional, para adopção de design de camadas intermĂ©dias, de forma a que as camadas de protocolos sejam concebidas para trabalhar em sinergia com o sistema anfitriĂŁo, ao invĂ©s de independentemente, para aproveitamento de energia.
Neste trabalho, nós exploramos o contexto da informação, cooperação e design de camadas intermédias para desenvolver blocos de construção energicamente eficientes e tecnologias agnósticas para redes móveis. Estes habilitadores (enablers) tecnológicos incluem um nó de descoberta de energia eficiente e cooperação de curto alcance para poupança energética em aparelhos móveis, complementado com agendamento inteligente, energicamente consciente, de forma a promover a poupança de energia do lado da rede. Analiticamente e simultaneamente, foram obtidos resultados e verificados em laboratório, num modelo de hardware protótipo. Resultados demonstram que pode ser obtido uma poupança energética acima dos 50%
Cellular, Wide-Area, and Non-Terrestrial IoT: A Survey on 5G Advances and the Road Towards 6G
The next wave of wireless technologies is proliferating in connecting things
among themselves as well as to humans. In the era of the Internet of things
(IoT), billions of sensors, machines, vehicles, drones, and robots will be
connected, making the world around us smarter. The IoT will encompass devices
that must wirelessly communicate a diverse set of data gathered from the
environment for myriad new applications. The ultimate goal is to extract
insights from this data and develop solutions that improve quality of life and
generate new revenue. Providing large-scale, long-lasting, reliable, and near
real-time connectivity is the major challenge in enabling a smart connected
world. This paper provides a comprehensive survey on existing and emerging
communication solutions for serving IoT applications in the context of
cellular, wide-area, as well as non-terrestrial networks. Specifically,
wireless technology enhancements for providing IoT access in fifth-generation
(5G) and beyond cellular networks, and communication networks over the
unlicensed spectrum are presented. Aligned with the main key performance
indicators of 5G and beyond 5G networks, we investigate solutions and standards
that enable energy efficiency, reliability, low latency, and scalability
(connection density) of current and future IoT networks. The solutions include
grant-free access and channel coding for short-packet communications,
non-orthogonal multiple access, and on-device intelligence. Further, a vision
of new paradigm shifts in communication networks in the 2030s is provided, and
the integration of the associated new technologies like artificial
intelligence, non-terrestrial networks, and new spectra is elaborated. Finally,
future research directions toward beyond 5G IoT networks are pointed out.Comment: Submitted for review to IEEE CS&
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