Unbalanced Energy Research Articles

Energy-balanced cooperative routing in multihop wireless networks

Cooperative communication (CC) allows multiple nodes to simultaneously transmit the same packet to the receiver so that the combined signal at the receiver can be correctly decoded. Since the CC can reduce the transmission power and extend the transmission coverage, it has been considered in minimum energy routing protocols to reduce the total energy consumption. However, previous research on cooperative routing only focuses on minimizing the total energy consumption from the source node to the destination node, which may lead to the unbalanced energy distribution among nodes. In this paper, we aim to study the impact of cooperative routing on balancing the energy distribution among nodes. By introducing a new routing scheme which carefully selects cooperative relay nodes and assigns their transmission power, our cooperative routing method can balance the remaining energy among neighboring nodes to maximize the lifetime of the network. Simulation results demonstrate that the proposed cooperative routing algorithm significantly balances the energy distribution and prolongs the lifetime of the network.

Energy-Efficient Routing Algorithm for WSNs in Underground mining

Wireless Sensor Networks (WSNs) technology has been used for security monitoring to provide a safe working environment for Underground mining miners. But, energy consumption is an important issue in the design of routing protocol in wireless sensor networks. For the problems of coal mine chain-type network topology, unbalanced information flow and energy consumption among nodes is serious uneven, we proposed a Liner Energy-Balanced Uneven Cluster Routing Protocol Algorithm for Underground Mining. The cluster head election mechanism of the algorithm considered the distance between nodes and base station node, nodes energy and nodes density. At the same time, the algorithm reduces the amount of computation when candidate nodes campaigning. We evaluate LEBUC and the results show that LEBUC effectively graded the wireless sensor network of coal mine’s hot zone problem and reduces network traffic and energy consumption. It extends the survival time of the network significantly.

QoS routing in wireless sensor networks—a survey

A wireless sensor network (WSN) is a one made up of small sensing devices equipped with processors, memory, and short-range wireless communication. Sensor nodes, are autonomous nodes, which include smart dust sensors, motes and so on. They co-operatively monitor physical or environmental conditions and send the sensed data to the sink node. They differ from traditional computer networks due to resource constraints, unbalanced mixture traffic, data redundancy, network dynamics, and energy balance. These kinds of networks support a wide range of applications that have strong requirements to reduce end-to-end delay and losses during data transmissions. When large numbers of sensors are deployed in a sensor field and are active in transmitting the data, there is a possibility of congestion. Congestion may occur due to buffer overflow, channel contention, packet collision, a high data rate, many to one nature, and so on. This leads to packet loss which causes a decrease in throughput and lifetime. Maximum throughput, energy efficiency and minimum error rate can be achieved by minimizing the congestion. A number of quality of service (QoS) techniques has been developed to improve the quality of the network. This article gives an overview of existing QoS techniques and a parametric comparison made with recent developments. This article mainly concentrates on network congestion in WSN environment.

Fundamental Lifetime Mechanisms in Routing Protocols for Wireless Sensor Networks: A Survey and Open Issues

Wireless sensor networks basically consist of low cost sensor nodes which collect data from environment and relay them to a sink, where they will be subsequently processed. Since wireless nodes are severely power-constrained, the major concern is how to conserve the nodes' energy so that network lifetime can be extended significantly. Employing one static sink can rapidly exhaust the energy of sink neighbors. Furthermore, using a non-optimal single path together with a maximum transmission power level may quickly deplete the energy of individual nodes on the route. This all results in unbalanced energy consumption through the sensor field, and hence a negative effect on the network lifetime. In this paper, we present a comprehensive taxonomy of the various mechanisms applied for increasing the network lifetime. These techniques, whether in the routing or cross-layer area, fall within the following types: multi-sink, mobile sink, multi-path, power control and bio-inspired algorithms, depending on the protocol operation. In this taxonomy, special attention has been devoted to the multi-sink, power control and bio-inspired algorithms, which have not yet received much consideration in the literature. Moreover, each class covers a variety of the state-of-the-art protocols, which should provide ideas for potential future works. Finally, we compare these mechanisms and discuss open research issues.

Energy-Efficient Chain Formation Algorithm for Data Gathering in Wireless Sensor Networks

In wireless sensor networks, since sensor nodes are distributed in inaccessible regions for data gathering, they need to be operated during an assigned time without battery recharging and relocation. For this reason, there has been abundant research on improving energy efficiency. PEGASIS, one of the well-known chain-based routing protocols for improving energy efficiency, builds a chain based on the greedy algorithm. However, due to long communication distance of some sensor nodes in a chain formed by the greedy algorithm, unbalanced energy consumption of sensor nodes occurs. Eventually, the network lifetime from this cause decreases. We propose energy efficient chain formation (EECF) algorithm to resolve the unbalanced energy consumption problem caused by long-distance data transmission of some nodes in a chain formed by the greedy algorithm. The simulation results are used to verify the energy consumption balance of sensor nodes and the whole network lifetime. In simulation, it is shown that EECF produces better results than the greedy algorithm.

Evaluation of the deformation and corresponding dosimetric implications in prostate cancer treatment

The cone-beam computed tomography (CBCT) imaging modality is an integral component of image-guided adaptive radiation therapy (IGART), which uses patient-specific dynamic/temporal information for potential treatment plan modification. In this study, an offline process for the integral component IGART framework has been implemented that consists of deformable image registration (DIR) and its validation, dose reconstruction, dose accumulation and dose verification. This study compares the differences between planned and estimated delivered doses under an IGART framework of five patients undergoing prostate cancer radiation therapy. The dose calculation accuracy on CBCT was verified by measurements made in a Rando pelvic phantom. The accuracy of DIR on patient image sets was evaluated in three ways: landmark matching with fiducial markers, visual image evaluation and unbalanced energy (UE); UE has been previously demonstrated to be a feasible method for the validation of DIR accuracy at a voxel level. The dose calculated on each CBCT image set was reconstructed and accumulated over all fractions to reflect the ‘actual dose’ delivered to the patient. The deformably accumulated (delivered) plans were then compared to the original (static) plans to evaluate tumor and normal tissue dose discrepancies. The results support the utility of adaptive planning, which can be used to fully elucidate the dosimetric impact based on the simulated delivered dose to achieve the desired tumor control and normal tissue sparing, which may be of particular importance in the context of hypofractionated radiotherapy regimens.

An energy-balancing clustering approach for gradient-based routing in wireless sensor networks

Clustering significantly reduces the energy consumption of each individual sensor in a wireless sensor network (WSN), and also increases the communication load on cluster heads. Because of the unbalanced energy consumption among cluster heads, the hot spots problem will arise when using the multihop forwarding model for the intercluster communication. Unequal clustering is an effective way to balance the energy consumption of cluster heads. In this paper, we present an Energy-Balancing unequal Clustering Approach for Gradient-based routing (EBCAG) in wireless sensor networks. It partitions the nodes into clusters of unequal size, and each sensor node maintains a gradient value, which is defined as its minimum hop count to the sink. The size of a cluster is decided by the gradient value of its cluster head, and the data gathered from the cluster members should follow the direction of descending gradient to reach the sink. Simulation results show that EBCAG balances the energy consumption among the cluster heads, and significantly improves the network lifetime.

Avoiding Energy Holes to Maximize Network Lifetime in Gradient Sinking Sensor Networks

Unbalanced energy consumption is an inherent problem in gradient sinking sensor networks. This uneven energy dissipation can lead to the existence of energy holes, and significantly reduce network lifetime. In this paper, our study is based on corona-based network division. We investigate the unbalanced energy consumption among nodes both within the same coronas and within different coronas. We take advantage of mixed-routing strategy to achieve balanced energy consumption among nodes both within the same coronas and within different coronas. Besides, once the mixed-routing strategy can not balance energy consumption in local areas, the strategy of nonuniform energy distribution is used in these areas. Finally, we give algorithms to compute the optimal data distribution ratio and the initial energy of nodes. Simulation results show that our strategy can reduce the energy consumption, avoid energy holes and prolong the network lifetime dramatically.

MO-F-BRA-04: Voxel-Based Statistical Analysis of Deformable Image Registration Error via a Finite Element Method.

Purpose Clinical implementation of adaptive treatment planning is limited by the lack of quantitative tools to assess deformable image registration errors (R-ERR). The purpose of this study was to develop a method, using finite element modeling (FEM), to estimate registration errors based on mechanical changes resulting from them. Methods An experimental platform to quantify the correlation between registration errors and their mechanical consequences was developed as follows: diaphragm deformation was simulated on the CT images in patients with lung cancer using a finite element method (FEM). The simulated displacement vector fields (F-DVF) were used to warp each CT image to generate a FEM image. B-Spline based (Elastix) registrations were performed from reference to FEM images to generate a registration DVF (R-DVF). The F- DVF was subtracted from R-DVF. The magnitude of the difference vector was defined as the registration error, which is a consequence of mechanically unbalanced energy (UE), computed using 'in-house-developed' FEM software. A nonlinear regression model was used based on imaging voxel data and the analysis considered clustered voxel data within images. Results A regression model analysis showed that UE was significantly correlated with registration error, DVF and the product of registration error and DVF respectively with R̂2=0.73 (R=0.854). The association was verified independently using 40 tracked landmarks. A linear function between the means of UE values and R- DVF*R-ERR has been established. The mean registration error (N=8) was 0.9 mm. 85.4% of voxels fit this model within one standard deviation. Conclusions An encouraging relationship between UE and registration error has been found. These experimental results suggest the feasibility of UE as a valuable tool for evaluating registration errors, thus supporting 4D and adaptive radiotherapy. The research was supported by NIH/NCI R01CA140341.

Effective punching shear and moment capacity of flat plate-column connection with shear reinforcements for lateral loading

Abstract In this study, three isolated interior flat slab-column connections that include three types of shear reinforcement details; stirrup, shear stud and shear band were tested under reversed cyclic lateral loading to observe the capacity of slab-column connections. These reinforced joints are 2/3 scale miniatures designed to have identical punching capacities. These experiments showed that the flexural failure mode appears in most specimens while the maximum unbalanced moment and energy absorbing capacity increases effectively, with the exception of an unreinforced standard specimen. Finally, the results of the experiments, as wel l as those of experiments previously carried out by researchers, are applied to the eccentricity shear stress model presented in ACI 318-08. The failure mode is therefore defined in this study by considering the upper limits for punching shear and unbalanced momen t. In addition, an intensity factor is proposed for effective widths of slabs that carry an unbalanced moment delivered by bending.

Research of Wireless Sensor Routing Algorithm Based on Uneven Clustering

Among traditional wireless sensor routing algorithm like LEACH, problems like unbalanced energy consumption in wireless sensor network, node losing efficacy because of large energy consumption, period uncertainty of periodic cluster head and unbalanced energy consumption between clusters come into being. Aiming at problem of unbalanced energy consumption between wireless sensor clusters, uneven clustering strategy is used in this research. Aiming at problem in the selection of periodic clustering head, clustering head rotation mechanism based on energy threshold is used in this research. In this research, 100 sensor nodes randomly exist in a square area whose radius is 400M. Sink node is in the centre of the square area. Sensor node collects data every 2s and sends monitoring data meanwhile. Simulation result shows that total energy consumption of clustering head of the improved algorithm is far less than that of traditional LEACH algorithm in which survival rate of node is also greatly developed.

Energy Efficient and Balanced Cluster-Based Data Aggregation Algorithm for Wireless Sensor Networks

Data aggregation is an effectual approach for wireless sensor networks (WSNs) to save energy and prolong network lifetime. Cluster-based data aggregation algorithms are most popular because they have the advantages of high flexibility and reliability. But the problem of unbalanced energy dissipation is the inherent disadvantage in clusterbased WSNs. This paper addresses this problem in cluster-based and homogeneous WSNs in which cluster heads transmit data to base station by one-hop communication, and proposes an energy efficient and balanced cluster-based data aggregation algorithm (EEBCDA). It divides the network into rectangular grids with unequal size and makes cluster heads rotate among the nodes in each grid respectively, the grid whose cluster head consumes more energy has more sensor nodes to take part in cluster head rotation and share energy load, by this way, it is able to balance energy dissipation. Besides, it adopts some measures to save energy. The results of simulation show that EEBCDA can remarkably enhance energy efficiency, balance energy dissipation and prolong network lifetime.

Energy Consumption Analysis on Gradient Sinking Model in Wireless Sensor Networks

In a wireless sensor network based on the gradient sinking model, unbalanced energy consumption is an inherent problem and can significantly reduce the network lifetime. In this letter, we propose a subcorona-based scheme to analyze the amount of received data and energy consumption of nodes on gradient sinking model. We then design an algorithm to compute the energy consumption of nodes in different subcoronas. Simulation results indicate the correctness of our proposed algorithm.

Lifetime Enhancement in Wireless Sensor Networks Using Fuzzy Approach and A-Star Algorithm

Wireless sensor networks (WSNs) are used in many applications to gather sensitive information which is then forwarded to an analysis center. Resource limitations have to be taken into account when designing a WSN infrastructure. Unbalanced energy consumption is an inherent problem in WSNs, characterized by multihop routing and a many-to-one traffic pattern. This uneven energy dissipation can significantly reduce network lifetime. This paper proposes a new routing method for WSNs to extend network lifetime using a combination of a fuzzy approach and an A-star algorithm. The proposal is to determine an optimal routing path from the source to the destination by favoring the highest remaining battery power, minimum number of hops, and minimum traffic loads. To demonstrate the effectiveness of the proposed method in terms of balancing energy consumption and maximization of network lifetime, we compare our approach with the A-star search algorithm and fuzzy approach using the same routing criteria in two different topographical areas. Simulation results demonstrate that the network lifetime achieved by the proposed method could be increased by nearly 25% more than that obtained by the A-star algorithm and by nearly 20% more than that obtained by the fuzzy approach.

A UWB Unidirectional Antenna With Dual-Polarization

A novel ±45° dual-polarized unidirectional antenna element is presented, consisting of two cross center-fed tapered mono-loops and two cross electric dipoles located against a reflector for ultrawideband applications. The operation principle of the antenna including the use of elliptically tapered transmission line for transiting the unbalanced energy to the balanced energy is described. Designs with different reflectors-planar or conical-are investigated. A measured overlapped impedance bandwidth of 126% (SWR <; 2) is demonstrated. Due to the complementary nature of the structure, the antenna has a relatively stable broadside radiation pattern with low cross polarization and low back lobe radiation over the operating band. The measured gain of the proposed antenna varies from 4 to 13 dBi and 7 to 14.5 dBi for port 1 and port 2, respectively, over the operating band, when mounted against a conical backed reflector. The measured coupling between the two ports is below -25 dB over the operating band.

Dietary fat and not calcium supplementation or dairy product consumption is associated with changes in anthropometrics during a randomized, placebo-controlled energy-restriction trial

Insufficient calcium intake has been proposed to cause unbalanced energy partitioning leading to obesity. However, weight loss interventions including dietary calcium or dairy product consumption have not reported changes in lipid metabolism measured by the plasma lipidome.MethodsThe objective of this study was to determine the relationships between dairy product or supplemental calcium intake with changes in the plasma lipidome and body composition during energy restriction. A secondary objective of this study was to explore the relationships among calculated macronutrient composition of the energy restricted diet to changes in the plasma lipidome, and body composition during energy restriction. Overweight adults (n = 61) were randomized into one of three intervention groups including a deficit of 500kcal/d: 1) placebo; 2) 900 mg/d calcium supplement; and 3) 3-4 servings of dairy products/d plus a placebo supplement. Plasma fatty acid methyl esters of cholesterol ester, diacylglycerol, free fatty acids, lysophosphatidylcholine, phosphatidylcholine, phosphatidylethanolamine and triacylglycerol were quantified by capillary gas chromatography.ResultsAfter adjustments for energy and protein (g/d) intake, there was no significant effect of treatment on changes in weight, waist circumference or body composition. Plasma lipidome did not differ among dietary treatment groups. Stepwise regression identified correlations between reported intake of monounsaturated fat (% of energy) and changes in % lean mass (r = -0.44, P < 0.01) and % body fat (r = 0.48, P < 0.001). Polyunsaturated fat intake was associated with the % change in waist circumference (r = 0.44, P < 0.01). Dietary saturated fat was not associated with any changes in anthropometrics or the plasma lipidome.ConclusionsDairy product consumption or calcium supplementation during energy restriction over the course of 12 weeks did not affect plasma lipids. Independent of calcium and dairy product consumption, short-term energy restriction altered body composition. Reported dietary fat composition of energy restricted diets was associated with the degree of change in body composition in these overweight and obese individuals.

Application of α-methylstyrene/PE Composite Membrane with Enhanced Stability in the All-Vanadium Redox Flow Battery

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Energy-Balanced Transmission Policies for Wireless Sensor Networks

Transmission policy, in addition to topology control, routing, and MAC protocols, can play a vital role in extending network lifetime. Existing transmission policies, however, cause an extremely unbalanced energy usage that contributes to early demise of some sensors reducing overall network's lifetime drastically. Considering cocentric rings around the sink, we decompose the transmission distance of traditional multihop scheme into two parts: ring thickness and hop size, analyze the traffic and energy usage distribution among sensors and determine how energy usage varies and critical ring shifts with hop size. Based on above observations, we propose a transmission scheme and determine the optimal ring thickness and hop size by formulating network lifetime as an optimization problem. Numerical results show substantial improvements in terms of network lifetime and energy usage distribution over existing policies. Two other variations of this policy are also presented by redefining the optimization problem considering: 1) concomitant hop size variation by sensors over lifetime along with optimal duty cycles, and 2) a distinct set of hop sizes for sensors in each ring. Both variations bring increasingly uniform energy usage with lower critical energy and further improves lifetime. A heuristic for distributed implementation of each policy is also presented.

The balance of routing energy consumption in wireless sensor networks

In order to tackle the energy hole problem of sensor networks, the non-uniform node deployment strategy was presented recently. For achieving the expected performance of this deployment method, nodes need to transmit data to the sink node by selecting a node in the adjacent inner region decided by the deployment strategy. Since nodes near the outer boundary of a region will be covered by more nodes, the random selection method will cause the unbalanced energy consumption problem. In this paper, this issue is rigorously studied and a region constraint selection scheme is proposed based on the analytical result. By combining the region constraint strategy and the maximum energy node selection mechanism, a hybrid scheme is presented. Numerical and simulation results show that the region constraint scheme can achieve acceptable performance improvements over the random scheme and the hybrid mechanism also gains better performance in comparison to the maximum energy node selection scheme.

TMHF: Transmit Max Hop First forwarding Strategy to Optimize the Performance of Epidemic Routing Protocol

Tolerant Networks vary from conventional networks in that they have reserve constraints, unbalanced mixture traffic, data redundancy, network dynamics, and energy balance. Moreover due to node mobility DTN suffers from unpredictable connectivity and limited transmission duration. A mobile node in DTN routing may not be able to transmit all messages from its forwarding queue; therefore the order in which messages are transmitted becomes very important. In this paper, we propose forwarding queuing mechanisms named Transmit Max Hop Count first (TMHF) in which when the connection opportunity arises, the node will transmit the message with max hop count.