scholarly journals Geographic and Opportunistic Recovery with Depth and Power Transmission Adjustment for Energy-Efficiency and Void Hole Alleviation in UWSNs

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 709 ◽  
Author(s):  
Abdul Mateen ◽  
Muhammad Awais ◽  
Nadeem Javaid ◽  
Farruh Ishmanov ◽  
Muhammad Afzal ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Routing Protocols ◽  
Power Transmission ◽  
State Of The Art ◽  
Maximum Energy ◽  
Underwater Wireless Sensor Networks ◽  
Routing Schemes ◽  
End To End Delay ◽  
Extra Energy ◽  
Wide Range

Underwater Wireless Sensor Networks (UWSNs) are promising and emerging frameworks having a wide range of applications. The underwater sensor deployment is beneficial; however, some factors limit the performance of the network, i.e., less reliability, high end-to-end delay and maximum energy dissipation. The provisioning of the aforementioned factors has become a challenging task for the research community. In UWSNs, battery consumption is inevitable and has a direct impact on the performance of the network. Most of the time energy dissipates due to the creation of void holes and imbalanced network deployment. In this work, two routing protocols are proposed to avoid the void hole and extra energy dissipation problems which, due to which lifespan of the network increases. To show the efficacy of the proposed routing schemes, they are compared with the state of the art protocols. Simulation results show that the proposed schemes outperform the counterparts.

Clustering-based Energy Efficient Multipath Adaptive Routing Protocols for Underwater Wireless Sensor Networks

2020 ◽  
Vol 6 (2) ◽  
pp. EC-54-EC-62
Author(s):  
Edy Victor Haryanto ◽  
Keyword(s):  
Routing Protocol ◽  
Routing Protocols ◽  
Energy Efficient ◽  
Transmission Rate ◽  
Adaptive Routing ◽  
Maximum Energy ◽  
Wireless Sensor ◽  
Energy Usage ◽  
Underwater Wireless Sensor Networks

In an underwater wireless sensor network (UWSN), research challenges occur in the availability of new connectivity protocols, sensors, and utilization of energy. One of the issues is to enhance the lifespan of the network without increasing the supply, cost, and level of resources. This paper proposes a conceptual routing protocol for UWSN, known as Energy-Efficient Multipath Adaptive Routing (E2MAR) protocols, which is primarily intended for long-term control with greater energy efficiency and transmission rate. Key development conditions were set by the E2MR and forward nodes are chosen based on the performance index. Different tests are carried out by evaluating E2MR in terms of the number of live nodes, end-to-end latency, packet delivery rate, and maximum energy usage efficiently compared to some other Routing protocols. The lifespan of the network has also been greatly enhanced.

Routing Protocols for Ad-Hoc Networks

2011 ◽  
pp. 178-221
Author(s):  
Muhammad Mahmudul Islam ◽  
Ronald Pose ◽  
Carlo Kopp
Keyword(s):  
Ad Hoc Networks ◽  
Routing Protocols ◽  
Ad Hoc ◽  
Dynamic Features ◽  
Ad Hoc Routing ◽  
Related Research ◽  
Routing Schemes ◽  
Wired Networks ◽  
Wide Range ◽  
Hoc Networks

Ad-hoc networks have been the focus of research interest in wireless networks since 1990. Nodes in an ad-hoc network can connect to each other dynamically in an arbitrary manner. The dynamic features of ad-hoc networks demand a new set of routing protocols that are different from the routing schemes used in traditional wired networks. A wide range of routing protocols has been proposed to overcome the limitations of wired routing protocols. This chapter outlines the working mechanisms of state-ofthe- art ad-hoc routing protocols. These protocols are evaluated by comparing their functionalities and characteristics. Related research challenges are also discussed.

scholarly journals Avoiding Void Holes and Collisions with Reliable and Interference-Aware Routing in Underwater WSNs

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3038 ◽  
Author(s):  
Nadeem Javaid ◽  
Abdul Majid ◽  
Arshad Sher ◽  
Wazir Khan ◽  
Mohammed Aalsalem
Keyword(s):  
Routing Protocols ◽  
Dynamic Network ◽  
Packet Delivery Ratio ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Underwater Wireless Sensor Networks ◽  
Packet Delivery ◽  
End To End Delay ◽  
Probability Of Collision ◽  
Simulation Results

Sparse node deployment and dynamic network topology in underwater wireless sensor networks (UWSNs) result in void hole problem. In this paper, we present two interference-aware routing protocols for UWSNs (Intar: interference-aware routing; and Re-Intar: reliable and interference-aware routing). In proposed protocols, we use sender based approach to avoid the void hole. The beauty of the proposed schemes is that they not only avoid void hole but also reduce the probability of collision. The proposed Re-Intar also uses one-hop backward transmission at the source node to further improve the packet delivery ratio of the network. Simulation results verify the effectiveness of the proposed schemes in terms of end-to-end delay, packet delivery ratio and energy consumption.

scholarly journals Performance evaluation for vehicular ad-hoc networks based routing protocols

2021 ◽  
Vol 10 (2) ◽  
pp. 1080-1091
Author(s):  
Hussain Falih Mahdi ◽  
Mohammed Salah Abood ◽  
Mustafa Maad Hamdi
Keyword(s):  
Routing Protocols ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Delivery Ratio ◽  
Wireless Router ◽  
End To End Delay ◽  
Aodv Protocol ◽  
Wide Range ◽  
End To End ◽  
Hoc Networks

VANET is a branch of MANETS, where each vehicle is a node, and a wireless router will run. The vehicles are similar to each other will interact with a wide range of nodes or vehicles and establish a network. VANETs provide us with the infrastructure to build new solutions for improving safety and comfort for drivers and passengers. There are several routing protocols proposed and evaluated for improving VANET's performance. The simulator is preferred over external experience because it is easy, simple, and inexpensive. In this paper, we choose AODV protocol, DSDV protocol, and DSR protocol with five different nodes density. For each protocol, as regards specific parameters like (throughput, packet delivery ratio, and end- to- end delay). On simulators that allow users to build real-time navigation models of simulations using VANET. Tools (SUMO, MOVE, and NS-2) were used for this paper, then graphs were plotted for evaluation using Trace-graph. The results showed the DSR is much higher than AODV and DSDV, In terms of throughput. While DSDV is the best choice because of the low average end to end delay. From the above, we conclude that each strategy has its own negative and positive aspects that make it ideally suited to a particular scenario than other scenarios.

Energy Absorption and Dissipation Performance in Cycloid Guided Pendulum Absorbers

2010 ◽  
Author(s):  
Younes Rashidi ◽  
Siamak Arzanpour ◽  
Mehrzad Tabatabaian
Keyword(s):  
Energy Dissipation ◽  
Energy Absorption ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Maximum Energy ◽  
Single Frequency ◽  
Vibration Absorbers ◽  
Wide Range ◽  
Induced Motion ◽  
Energy Absorbers

The dynamic energy absorbers are auxiliary systems that are attached to the main structure and widely used as a simple solution for neutralization of vibrations. Among various types of pendulum vibration absorbers are preferable for high-rise buildings, bridges and other civil structures for suppression earthquake-excited vibrations. The problem in dissipating vibration of earthquake is its unknown characteristics such as excitation frequency and magnitude. As a result, designing of an effective self tuning vibration absorber that can adjust its performance according to the excitation frequency will be a challenge. The situation is to have an absorber that can respond at a single frequency for wide range of excitation amplitude so its parameter can be well adjusted for the maximum energy dissipation. It is shown [5] that period in cycloid pendulum is constant for large amplitude. This feature is a major advantage of cycloid pendulum absorbers that could be used in combination with an energy dissipation mechanism to reduce the induced motion in a structure. In this paper, two types of vibration absorbers, i.e., simple and cycloid pendulum are analytically compared. The simulation results demonstrate the superiority of the cycloid damper type in energy absorption/dissipation over a simple pendulum one.

CLINICAL AND FORENSIC ASPECTS OF PHARMACOBEZOARS

2020 ◽  
Vol 12 ◽  
Author(s):  
Francisco Basílio ◽  
Ricardo Jorge Dinis-Oliveira
Keyword(s):  
State Of The Art ◽  
Signs And Symptoms ◽  
Immediate Release ◽  
Diagnosis And Treatment ◽  
Blood Concentrations ◽  
Forensic Practice ◽  
Wide Range ◽  
Therapeutic Doses ◽  
Complete History ◽  
Lethal Blood

Background: Pharmacobezoars are specific types of bezoars formed when medicines, such as tablets, suspensions, and/or drug delivery systems, aggregate and may cause death by occluding airways with tenacious material or by eluting drugs resulting in toxic or lethal blood concentrations. Objective: This work aims to fully review the state-of-the-art regarding pathophysiology, diagnosis, treatment and other relevant clinical and forensic features of pharmacobezoars. Results: patients of a wide range of ages and in both sexes present with signs and symptoms of intoxications or more commonly gastrointestinal obstructions. The exact mechanisms of pharmacobezoar formation are unknown but is likely multifactorial. The diagnosis and treatment depend on the gastrointestinal segment affected and should be personalized to the medication and the underlying factor. A good and complete history, physical examination, image tests, upper endoscopy and surgery through laparotomy of the lower tract are useful for diagnosis and treatment. Conclusion: Pharmacobezoars are rarely seen in clinical and forensic practice. They are related to controlled or immediate-release formulations, liquid or non-digestible substances, in normal or altered digestive motility/anatomy tract, and in overdoses or therapeutic doses, and should be suspected in the presence of risk factors or patients taking drugs which may form pharmacobezoars.

Computers in Geology - 25 Years of Progress

1994 ◽  
Keyword(s):  
Computer Modeling ◽  
Quantitative Methods ◽  
State Of The Art ◽  
International Association ◽  
Mathematical Geology ◽  
25Th Anniversary ◽  
The Earth ◽  
Wide Range ◽  
History Of ◽  
Mapping Techniques

This volume vividly demonstrates the importance and increasing breadth of quantitative methods in the earth sciences. With contributions from an international cast of leading practitioners, chapters cover a wide range of state-of-the-art methods and applications, including computer modeling and mapping techniques. Many chapters also contain reviews and extensive bibliographies which serve to make this an invaluable introduction to the entire field. In addition to its detailed presentations, the book includes chapters on the history of geomathematics and on R.G.V. Eigen, the "father" of mathematical geology. Written to commemorate the 25th anniversary of the International Association for Mathematical Geology, the book will be sought after by both practitioners and researchers in all branches of geology.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

scholarly journals Density Guarantee on Finding Multiple Subgraphs and Subtensors

2021 ◽  
Vol 15 (5) ◽  
pp. 1-32
Author(s):  
Quang-huy Duong ◽  
Heri Ramampiaro ◽  
Kjetil Nørvåg ◽  
Thu-lan Dam
Keyword(s):  
Lower Bound ◽  
State Of The Art ◽  
The State ◽  
The Other ◽  
Exact Methods ◽  
Practical Solution ◽  
Novel Approach ◽  
Wide Range ◽  
Real World Datasets ◽  
Tensor Data

Dense subregion (subgraph & subtensor) detection is a well-studied area, with a wide range of applications, and numerous efficient approaches and algorithms have been proposed. Approximation approaches are commonly used for detecting dense subregions due to the complexity of the exact methods. Existing algorithms are generally efficient for dense subtensor and subgraph detection, and can perform well in many applications. However, most of the existing works utilize the state-or-the-art greedy 2-approximation algorithm to capably provide solutions with a loose theoretical density guarantee. The main drawback of most of these algorithms is that they can estimate only one subtensor, or subgraph, at a time, with a low guarantee on its density. While some methods can, on the other hand, estimate multiple subtensors, they can give a guarantee on the density with respect to the input tensor for the first estimated subsensor only. We address these drawbacks by providing both theoretical and practical solution for estimating multiple dense subtensors in tensor data and giving a higher lower bound of the density. In particular, we guarantee and prove a higher bound of the lower-bound density of the estimated subgraph and subtensors. We also propose a novel approach to show that there are multiple dense subtensors with a guarantee on its density that is greater than the lower bound used in the state-of-the-art algorithms. We evaluate our approach with extensive experiments on several real-world datasets, which demonstrates its efficiency and feasibility.

Efficient Directed Densest Subgraph Discovery

2021 ◽  
Vol 50 (1) ◽  
pp. 33-40
Author(s):  
Chenhao Ma ◽  
Yixiang Fang ◽  
Reynold Cheng ◽  
Laks V.S. Lakshmanan ◽  
Wenjie Zhang ◽  
...  
Keyword(s):  
Approximation Algorithms ◽  
State Of The Art ◽  
Exact Algorithms ◽  
Large Datasets ◽  
Dense Subgraph ◽  
Extensive Evaluation ◽  
Wide Range ◽  
Edge Graph ◽  
Community Mining ◽  
Densest Subgraph

Given a directed graph G, the directed densest subgraph (DDS) problem refers to the finding of a subgraph from G, whose density is the highest among all the subgraphs of G. The DDS problem is fundamental to a wide range of applications, such as fraud detection, community mining, and graph compression. However, existing DDS solutions suffer from efficiency and scalability problems: on a threethousand- edge graph, it takes three days for one of the best exact algorithms to complete. In this paper, we develop an efficient and scalable DDS solution. We introduce the notion of [x, y]-core, which is a dense subgraph for G, and show that the densest subgraph can be accurately located through the [x, y]-core with theoretical guarantees. Based on the [x, y]-core, we develop both exact and approximation algorithms. We have performed an extensive evaluation of our approaches on eight real large datasets. The results show that our proposed solutions are up to six orders of magnitude faster than the state-of-the-art.

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