• Energy Research

De nos jours, l'espérance de vie limitée de la batterie est un problème important pour la livraison fiable des données dans un réseau de capteurs sans fil sous-marin (UWSN). Les méthodologies de transmission conventionnelles augmentent le surdébit de transmission, c'est-à-dire la collision de paquets, qui influencent la transmission de données. Le remplacement de la batterie des capteurs dans un environnement sous-marin brutal est une tâche difficile. Par conséquent, pour maintenir une distance stratégique par rapport à la défaillance inattendue du réseau et augmenter la durée de vie du réseau, des protocoles de routage écoénergétiques sont nécessaires. À cette fin, dans cet article, un protocole de routage proactif avec trois types de réseau différents est proposé pour résoudre les problèmes susmentionnés. Le protocole proposé modifie de manière adaptative sa stratégie de communication en fonction du type de réseau, c'est-à-dire un réseau dense, un réseau partiellement dense et un réseau clairsemé. Cette stratégie adaptative aide les protocoles de routage à poursuivre leur transmission en évitant les trous de vide. Dans le protocole proposé appelé Approche de routage proactive avec sélection de chemin économe en énergie (PA-EPS-Case I), le concept de superposition d'intertransmission verticale est introduit (en utilisant le chemin le plus court et le plus rapide) dans la région dense et partiellement dense. En outre, le concept de formation de grappes est également ajouté pour assurer le succès de la transmission dans les régions éparses. Le taux de livraison des paquets (PDR) est amélioré par le protocole proposé avec un retard de bout en bout (E2E) minimum et un taux de chute des paquets. L'évolutivité des protocoles de routage proposés est également analysée en faisant varier le nombre de nœuds de 100 à 500. Une analyse comparative est effectuée avec deux protocoles de routage de pointe, à savoir : la profondeur de pondération et le routage basé sur la profondeur de la division de la zone d'acheminement (WDFAD-DBR) et le WDFAD-DBR basé sur le cluster (C-DBR). Les résultats de la simulation démontrent que le protocole proposé a atteint un PDR supérieur de 12,64 % avec une diminution de 20 % du délai E2E par rapport au C-DBR. En outre, le protocole de routage proposé a surpassé C-DBR en termes de taux de chute de paquets jusqu'à 14,29 % avec une augmentation de la CE jusqu'à 30 %. Hoy en día, la esperanza de vida limitada de la batería es un problema importante para la entrega confiable de datos en una red de sensores inalámbricos submarinos (UWSN). Las metodologías de transmisión convencionales aumentan la sobrecarga de transmisión, es decir, la colisión de paquetes, que influyen en la transmisión de datos. La sustitución de la batería de los sensores en un entorno submarino brutal es una tarea difícil. Por lo tanto, para mantener una distancia estratégica de la falla inesperada de la red y aumentar la esperanza de vida de la red, se requieren protocolos de enrutamiento energéticamente eficientes. En este sentido, en este trabajo, se propone un protocolo de enrutamiento proactivo con tres tipos de red diferentes para resolver los problemas antes mencionados. El protocolo propuesto cambia de forma adaptativa su estrategia de comunicación en función del tipo de red, es decir, red densa, red parcialmente densa y red dispersa. Esta estrategia adaptativa ayuda a los protocolos de enrutamiento a continuar su transmisión evitando los huecos. En el protocolo propuesto denominado Enfoque de enrutamiento proactivo con selección de ruta de eficiencia energética (PA-EPS-Caso I), se introduce el concepto de capas verticales entre transmisiones (utilizando la ruta más corta y rápida) en la región densa y parcialmente densa. Además, también se adjunta el concepto de formación de clústeres para que la transmisión sea exitosa en las regiones dispersas. La relación de entrega de paquetes (PDR) se mejora mediante el protocolo propuesto con un retraso mínimo de extremo a extremo (E2E) y una relación de caída de paquetes. La escalabilidad de los protocolos de enrutamiento propuestos también se analiza variando el número de nodos de 100 a 500. Se realiza un análisis comparativo con dos protocolos de enrutamiento de vanguardia, a saber: enrutamiento basado en profundidad de división de área de ponderación y reenvío (WDFAD-DBR) y WDFAD-DBR basado en clústeres (C-DBR). Los resultados de la simulación demuestran que el protocolo propuesto logró una PDR un 12,64% más alta con una disminución del 20% en el retraso de E2E que la C-DBR. Además, el protocolo de enrutamiento propuesto superó a C-DBR en términos de tasa de caída de paquetes hasta el 14,29% con un aumento de EC de hasta el 30%. Nowadays, constrained battery life expectancy is an important issue for reliable data delivery in an Underwater Wireless Sensor Network (UWSN). Conventional transmission methodologies increase the transmission overhead, i.e., the collision of packets, which influence the data transmission. Replacement of the sensors' battery in brutal underwater environment is a difficult task. Therefore, to maintain a strategic distance from the unexpected failure of the network and to increase the life expectancy of the network, energy efficient routing protocols are required. At this end, in this paper, a proactive routing protocol with three different network types is proposed to solve the aforementioned issues. The proposed protocol adaptively changes its communication strategy depending on the type of the network, i.e., dense network, partially dense network and sparse network. This adaptive strategy helps the routing protocols to continue their transmission by avoiding the void holes. In the proposed protocol named Proactive routing Approach with Energy efficient Path Selection (PA-EPS-Case I), vertical inter-transmission layering concept is introduced (using shortest and fastest path) in the dense and partially dense region. In addition, cluster formation concept is also appended to make transmission successful in the sparse regions. The Packet Delivery Ratio (PDR) is improved by the proposed protocol with minimum End to End (E2E) delay and packet drop ratio. Scalability of the proposed routing protocols is also analyzed by varying the number of nodes from 100-500. A comparative analysis is performed with two cutting edge routing protocols namely: Weighting Depth and Forwarding Area Division Depth Based Routing (WDFAD-DBR) and Cluster-based WDFAD-DBR (C-DBR). Simulation results demonstrate that proposed protocol achieved 12.64% higher PDR with 20% decrease in E2E delay than C-DBR. Furthermore, the proposed routing protocol outperformed C-DBR in terms of packet drop ratio up to 14.29% with an increase of EC up to 30%. في الوقت الحاضر، يعد العمر المتوقع للبطارية المقيد مشكلة مهمة لتوصيل البيانات الموثوقة في شبكة الاستشعار اللاسلكية تحت الماء (UWSN). تزيد منهجيات الإرسال التقليدية من النفقات العامة للإرسال، أي تصادم الحزم، مما يؤثر على نقل البيانات. يعد استبدال بطارية المستشعرات في بيئة قاسية تحت الماء مهمة صعبة. لذلك، للحفاظ على مسافة استراتيجية من الفشل غير المتوقع للشبكة ولزيادة العمر المتوقع للشبكة، يلزم وجود بروتوكولات توجيه موفرة للطاقة. في هذه النهاية، في هذه الورقة، يُقترح بروتوكول توجيه استباقي مع ثلاثة أنواع مختلفة من الشبكات لحل المشكلات المذكورة أعلاه. يغير البروتوكول المقترح بشكل تكيفي استراتيجية الاتصال الخاصة به اعتمادًا على نوع الشبكة، أي الشبكة الكثيفة والشبكة الكثيفة جزئيًا والشبكة المتفرقة. تساعد هذه الاستراتيجية التكيفية بروتوكولات التوجيه على مواصلة انتقالها عن طريق تجنب ثقوب الفراغ. في البروتوكول المقترح المسمى نهج التوجيه الاستباقي مع اختيار المسار الموفر للطاقة (PA - EPS - Case I)، يتم تقديم مفهوم الطبقات العمودية بين الإرسال (باستخدام أقصر وأسرع مسار) في المنطقة الكثيفة والكثيفة جزئيًا. بالإضافة إلى ذلك، يتم إلحاق مفهوم تكوين التجمعات أيضًا لجعل انتقال العدوى ناجحًا في المناطق المتناثرة. يتم تحسين نسبة تسليم الحزمة (PDR) من خلال البروتوكول المقترح مع الحد الأدنى من التأخير من النهاية إلى النهاية (E2E) ونسبة إسقاط الحزمة. كما يتم تحليل قابلية التوسع في بروتوكولات التوجيه المقترحة من خلال تغيير عدد العقد من 100 إلى 500. يتم إجراء تحليل مقارن مع اثنين من بروتوكولات التوجيه المتطورة وهي: عمق الترجيح والتوجيه القائم على عمق تقسيم منطقة إعادة التوجيه (WDFAD - DBR) و WDFAD - DBR القائم على الكتلة (C - DBR). تُظهر نتائج المحاكاة أن البروتوكول المقترح حقق PDR أعلى بنسبة 12.64 ٪ مع انخفاض بنسبة 20 ٪ في تأخير E2E مقارنة بـ C - DBR. علاوة على ذلك، تفوق بروتوكول التوجيه المقترح على C - DBR من حيث نسبة إسقاط الحزمة حتى 14.29 ٪ مع زيادة قدرها EC تصل إلى 30 ٪.

As IoT applications proliferate, the demand for energy-efficient data processing becomes increasingly vital, particularly for devices operating under power constraints. This paper introduces a novel Discrete Cosine Transform (DCT) architecture implemented using reversible logic to meet the requirements for effective data compression in IoT systems, such as smart surveillance and wearable health monitors. The proposed 8-point fully parallel DCT leverages a customized datapath based on a standard cell approach, integrating pass transistor logic and a full custom layout in UMC 90 nm CMOS technology. Comprehensive validation through functional simulations and design rule checks demonstrates the architecture’s reliability. With a compact core area of 0.806 mm2, the DCT operates at a low power consumption of just 1.12 mW, achieving a clock frequency of 257 MHz. This low-power design facilitates significant energy savings while maintaining high performance and low complexity, making it well-suited for energy-constrained IoT applications.

Efficient power line outage identification is an important step which ensures reliable and smooth operation of smart grids. The problem of multiple line outage detection (MLOD) is formulated as a combinatorial optimization problem and known to be NP-hard. Such a problem is optimally solvable with the help of an exhaustive evaluation of all possible combinations of lines in outage. However, the size of search space is exponential with the number of power lines in the grid, which makes exhaustive search infeasible for practical sized smart grids. A number of published works on MLOD are limited to identify a small, constant number of lines outages, usually known to the algorithm in advanced. This paper applies the Bayesian approach to solve the MLOD problem in linear time. In particular, this paper proposes a low complexity estimation of outage detection algorithm, based on the classical estimation of distribution algorithm. Thanks to an efficient thresholding routine, the proposed solution avoids the premature convergence and is able to identify any arbitrary number (combination) of line outages. The proposed solution is validated against the IEEE-14 and 57 bus systems with several random line outage combinations. Two performance metrics, namely, success generation ratio and percentage improvement have been introduced in this paper, which quantify the accuracy as well as convergence speed of proposed solution. The comparison results demonstrate that the proposed solution is computationally efficient and outperforms a number of classical meta-heuristics.

Abstract Accurate and prompt identification of power line outages plays an important role in the reliability and robustness of smart power grids. Line outage identification problem has been traditionally formulated as a combinatorial optimization problem and requires an exhaustive search to find an optimal solution. However, this suffers from huge computational complexity as the size of the search space grows exponentially with the number of line outages. This work proposes a computationally efficient optimization technique based on Quantum Inspired Evolutionary Algorithm (QIEA) for the identification of multiple power line outages in smart power grids. In addition to the classical QIEA, a customized version of QIEA is also proposed and its effectiveness is validated against various IEEE bus systems with multiple line outages scenarios. The simulation results demonstrate the validity and accuracy of the proposed solution.

To avoid blackouts in the energy system, the knowledge of the state of the power lines has critical importance. To get the timely conscience, Phasor Measurement Units (PMUs) are used to provide real-time synchronized measurements of voltage and current phasors of the buses. The deployment of PMUs is done to first detect any single or multiple line outage, and further to identify the correct line in outage. But if these approaches are applied to more multiple line outages, the search space grows exponentially. To reduce the computational complexity in case of multiple line outage detection, stochastic optimization methods can be used. These methods give near optimal solution with an acceptable computational complexity. In this paper, the use of phasor angle measurements and optimal deployment of PMUs to identify multiple power line outages is investigated. An adaptive version of estimation of distribution algorithm (EDA) is proposed to detect and identify the lines in outage. In this adaptive EDA thresholding technique is introduced in order to get better solutions. It is shown that the proposed algorithm is achieving a better success rate than the other evolutionary techniques.

Cooperative communication with RF energy harvesting relays has emerged as a promising technique to improve the reliability, coverage, longevity and capacity of future IoT networks. An efficient relay assignment with proper power allocation and splitting is required to satisfy the network’s QoS requirements. This work considers the resource management problem in decode and forward relay based cooperative IoT network. A realistic mathematical model is proposed for joint user admission, relay assignment, power allocation and splitting ratio selection problem. The optimization problem is a mixed integer non-linear problem (MINLP) whose objective is to maximize the overall sum rate (bps) while satisfying the practical network constraints. Further, an outer approximation algorithm is adopted which provides epsilon-optimal solution to the problem with guaranteed convergence and reasonable complexity. Simulations of the proposed solution are carried out for various network scenarios. The simulation results demonstrate that cooperative communication with diversity achieves a better admission of IoT users and increases not only their individual data rates but also the overall sum rate of an IoT network.

Abstract Realtime information relating to line outages has significant importance to pre-empt against the power system blackouts. Realtime information can be obtained by using phasor measurement units (PMUs) facilitating the realtime synchronized observations of voltage and current phasors at buses being monitored. Different optimization formulations including but not limited to linear, integer, stochastic, mixed integer and NP hard combinatorial optimization have been used to manipulate these phasor measurements for the detection of line outages. Single and double line outages can be addressed using combinatorial optimization but these are infeasible to apply for the detection of multiple line outages as the increased number of lines increases computational complexity. To alleviate the exponentially increased complexities of these combinatorial optimization problems, while investigating for multiple line outage, evolutionary, Estimation of Distribution Algorithm is used. This method gives near optimal solution in which computational complexity and time is reduced efficiently. In this paper we scrutinize the use of phasor angle measurements to detect multiple power line outages. The proposed EDA is compared with binary particle swarm optimization (BPSO) algorithm, adaptive BPSO and genetic algorithm (GA) in terms of line outage detection performance, fitness convergence w.r.t. iterations and time consumption. The simulation results depict that the proposed EDA outperforms the other state of the art algorithms.