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Over the past few years, dynamic spectrum access has been gaining an increasing attention as a solution to the spectrum scarcity problem. In this paper, a primary user detection technique based on Maximum A Posteriori estimation is proposed for dynamic spectrum access networks. In the proposed technique, a set of secondary users acting as sensing nodes send their individual decisions about the existence of the primary user to a central fusion center. The fusion center uses the received data to form a codeword then, applies the maximum a posteriori estimation rule to make a final decision regarding the presence of the primary user. The proposed technique takes into consideration the accuracy of the local decisions provided by the secondary users when making a final decision. In this paper, we analyze the performance of the proposed scheme and derive closed-form expressions for the upper bounds of the false alarm and misdetection probabilities. The results show that the proposed technique outperforms other combining techniques in terms of its ability to detect the primary user and, accordingly, minimizes the harmful interference to the licensed network. Moreover, the proposed technique achieves better performance at a lower number of reporting secondary users which compensates for the complexity of the maximum a posteriori estimation.

Over the past few years, dynamic spectrum access has been gaining an increasing attention as a solution to the spectrum scarcity problem. In this paper, a primary user detection technique based on Maximum A Posteriori estimation is proposed for dynamic spectrum access networks. In the proposed technique, a set of secondary users acting as sensing nodes send their individual decisions about the existence of the primary user to a central fusion center. The fusion center uses the received data to form a codeword then, applies the maximum a posteriori estimation rule to make a final decision regarding the presence of the primary user. The proposed technique takes into consideration the accuracy of the local decisions provided by the secondary users when making a final decision. In this paper, we analyze the performance of the proposed scheme and derive closed-form expressions for the upper bounds of the false alarm and misdetection probabilities. The results show that the proposed technique outperforms other combining techniques in terms of its ability to detect the primary user and, accordingly, minimizes the harmful interference to the licensed network. Moreover, the proposed technique achieves better performance at a lower number of reporting secondary users which compensates for the complexity of the maximum a posteriori estimation.

Over the past few years, dynamic spectrum access has been gaining an increasing attention as a solution to the spectrum scarcity problem. In this paper, a primary user detection technique based on Maximum A Posteriori estimation is proposed for dynamic spectrum access networks. In the proposed technique, a set of secondary users acting as sensing nodes send their individual decisions about the existence of the primary user to a central fusion center. The fusion center uses the received data to form a codeword then, applies the maximum a posteriori estimation rule to make a final decision regarding the presence of the primary user. The proposed technique takes into consideration the accuracy of the local decisions provided by the secondary users when making a final decision. In this paper, we analyze the performance of the proposed scheme and derive closed-form expressions for the upper bounds of the false alarm and misdetection probabilities. The results show that the proposed technique outperforms other combining techniques in terms of its ability to detect the primary user and, accordingly, minimizes the harmful interference to the licensed network. Moreover, the proposed technique achieves better performance at a lower number of reporting secondary users which compensates for the complexity of the maximum a posteriori estimation.

Abstract: As a result of increased global concern about sustainability and climate change issues; developed Countries committed to finding techniques to conserve resources and achieve a balanced development. Achieving such goals requires more efficient and responsive urban management tools. Accustomed tools are ineffective to enabling cities to achieve such goals. Since 1990, global awareness has been directed towards using ICT in urban management. Creating a smart self-organizing system to manage and monitor cities' performance can accelerate improving of economic competitiveness, sustainability and quality of life. Egypt has an ambitious strategy: Egypt's 2030 vision for achieving sustainability and improving the quality of life. while, current urban management systems cannot accomplish such tasks. Therefore, this paper aimed to develop a conceptual model for a GIS-based urban management tool that enabling Egyptian cities to achieve Egypt's vision 2030. To achieve this goal the researcher relied on: 1) Recognizing the city's self-organizing system and identifying the role of geographic information systems in managing the urban transformation process and monitoring the city's performance; 2) Evaluating the capability of key performance indicators that were developed to measure the achievement of Egypt's 2030 vision. To achieve the first goal, a systematic literature review was conducted; while to achieve the second goal, KPIs of Egypt's 2030 vision were assessed with using strategic objectives/KPIs matrix as well as using comparative analysis with international evaluating systems. The contribution of this paper is twofold: 1 - Theoretical contribution that built the bridge between the theory of self-organizing system and the management of cities; 2- Practical contribution represented by: a) the conceptual model, which helps in understanding the components of the smart system for monitoring and evaluating the performance of cities, and the relationship between them; and b) The evolved list of KPIs that track the city's performance in the six domains of city (economy, environment, mobility, living, community, and governance), to ensure achieving desired goals of Egypt's 2030 vision.

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.