Resource prediction-based routing using agents in mobile ad hoc networks

Signal Strength Reduction Effects in OCT Angiography

Mobile Ad hoc Networks (MANET) are structure less, autonomous wireless networks with mobile nodes that dynamically establish data transmission connections. Due to dynamic topological change, MANET routes are unbalanced and break repeatedly. Hence, providing efficient and reliable data delivery with effective utilization of network resources is a challenging issue to be considered in MANET. This paper proposes an instant-runoff Ranked Decision Forests Probit Regression-based Connectionist Multilayer Deep Neural Network (IRDFPR-CMDNN) for efficient data transmission and higher data delivery with a minimum end-to-end delay. This IRDFPR-CMDNN method performs route identification, data delivery, and route maintenance with more than three layers. Then the mobile nodes are sent to the input layer of the Connectionist Multilayer Deep Neural Network. In hidden layer 1, the Instant-runoff Ranked Decision Forests algorithm is applied for classifying the mobile nodes depending on the residual energy and load capacity. With selected mobile nodes, the Probit Regression is applied for finding the nearest neighboring nodes in the second hidden layer based on the link quality and received signal strength for route path establishment. Then multiple paths for routing are established from source to destination node and start to perform the data transmission. If link failure occurs during the data transmission, another alternative route with better link quality is selected for routing. In this way, energy-efficient data transmission is performed from source to destination with a higher data delivery rate and minimal time consumption. Experimental evaluation is carried out on energy consumption, packet delivery ratio, packet drop rate, throughput, and end-to-end delay with varying numbers of mobile nodes and data packets. Simulation results show that the IRDFPR-CMDNN technique effectively enhances data delivery, throughput and minimizes energy consumption, packet loss rate, delay with respect to conventional methods.

Naturopathic approaches to weight loss in clinical practice – a mixed methods study

This research evaluates the impact of weather parameter (temperature, pressure, humidity and wind speed) on satellite dishes and how it affects the quality of reception it gives using the data obtained from the Automated Weather Station and Signal Strength in Enugu State University of Science and Technology. The atmospheric components and signal strength were measured every two minutes daily in different months, on different days, and at a different time of the day from the station for period of nine months. The average results of these measurements were then taken and the data obtained from the measurements were tabulated and subsequently plotted in a graph to ascertain the variation in signal strength triggered by change in temperature, humidity, pressure and wind speed. It was observed from this research that the rise in atmospheric temperature, humidity and pressure will lead to a drop in strength of the signal generated by this station and vice versa. This indicated that signal strength is inversely proportional to atmospheric temperature, pressure and humidity; provided that for any of the giving components, others were observed constant, including the wind speed and direction which affects the positioning of satellite dishes. The correlation of the signal strength and atmospheric temperature, pressure and humidity were respectively r=-0.93, -0.97 and -0.92. It was observed that the atmospheric temperature, humidity, pressure and wind speed are mathematically inversely related.

The paper focuses on the seamless transmission of the medical data between two points of e-health ecosystem. To successfully transmit the data one need to have a reliable network with required minimum signal strength and distortion. Based on system performance and its stability in accordance with the network, there are certain and quick variations in the network that could lead to distortion of data. The variation of signal strength during observation ranges in between − 90 and − 185 dBm. Transmission of signals from the basement to other location needs minimum threshold signal − 147 dBm for transfer of data with suitable speed. During analysis it was observed that some of the networks are not able to respond in deep fading environment, i.e., for basement signal transmission due to their installation criterion. The medical data transmitted from the basement need suitable selection of network in the given area. The above parameters are applied to the few hospitals in Greater Noida. UP (India) where the readings were taken at their respective basements to represent the signal strength with its fading parameters. Normally the basement fading tends to 25–35 dB in case of reception. The selection criteria in this paper is based on signal strength measurement, coverage analysis and regression analysis, prevail, that Worldwide Interoperability for Microwave Access is the best suited network for transmission of medical data from one place to another place with minimum cost.

A new alignment mark implementation for color processing has been successfully tested in a joint activity between ASML and TOWER. Alignability and over lay performance have been proven by applying the combination of a pure high order mark design and a dual implementation using the ATHENA™ alignment sensor and a PAS5500/400 machine. By their very nature, the resists used in color filter processe s will absorb light at various wavelengths. While this makes them useful as color filters, it can noticeably reduce the si gnal strength of pattern images as seen by lithography alignment systems. The pure high order mark design enhances the signal strength. Exposing two of such mark pairs in a Metal Last layer with two different metal plateaus (in previous metal layers: “Metal Last - 1” and “Metal Last -2”) leads to two different optical mark depths and therefore mimics a four wavelength alignment system with ATHENA. In principle, the evaluated technique might be extended to more (than four) “wavelengths” as well as other process layers. Moreover, the use of scribe-line marks enhances productivity since no extra lithography step is required to expose Zero Layers. The performance of this implementation has been evaluated for 180-nm CMOS Image Sensor technology. This paper discusses the overlay and alignment results of the evaluation. Alignment parameters such as absolute signal strength and signal strength variation were studied in detail. It is shown that such mark implementation shows good alignability and easily meets the product overlay requirements of Image Sensor devices. Keywords : Alignment Sensor, Mark Design, Overlay, Color Resist, Image Sensor.

Signal-strength variations from a 100 mw, 107 MHz balloon-borne v.h.f.-f.m. transmitter have been explained in terms of interference between the direct wave and the wave reflected by the smooth surface surrounding the narrow-beam Yagi receiving antenna. A set of graphs of calculated signal strength for various representative reflecting surfaces (sea water, wet and dry soil and frozen snow-covered earth), which are smooth to within the Rayleigh criterion, show the need for consideration of these effects in the design of low-power v.h.f. telemetry systems. It is suggested that such predictable variations in signal strength can be used as a method of balloon range estimation over a range of 100-450 km whenever other methods are unavailable.

In this paper, we propose a simple and low-cost direction estimation method for a subject (e.g., a photographic subject) by observing the Wi-Fi signal strength using a directional antenna. Our goal is to find a specific person in a crowded environment such as an athletics tournament, where many people are identically dressed and in close proximity to each other. Our method suggests the direction of the moving subject to the photographer. In our system, a compact directional antenna attached to a camera receives Wi-Fi signals that originate from a device attached to the subject, and estimates the subject's direction on the basis of variances in the signal strength. Through experimental evaluations, we show that 68% of the results estimated on the basis of the variation in signal strength versus the swinging angle of the camera are accurate.

The goal of wireless sensor networks is the maximum data gathering. Factors like energy, memory, bandwidth and processing capability affects the characteristics of the network which implies in reduced data collection. To avoid the reduction in data collection, mobile sensor nodes are used. They cover large area in short time and these networks are called as mobile wireless sensor networks (MWSN). In MWSN, set routing is used as one of the routing method for maximum data collection. In which the entire network is divided into many sets. This routing algorithm is applied for each set with the consideration that there is no node failure in the network. Here this work shows that how a new route is discovered if a node fails in a set using the Foldable Lookup Table (FLT) method. Also FLT method is compared with the routing table developed by fuzzy variables. Simulation is performed with OMNET++ simulator. Result shows the effectiveness of node failure in terms of delay and packet drops and how the route is maintained during node failure is shown with respect to delay.

Mobility in wireless sensor networks poses unique challenges to the Medium Access Control (MAC) protocol design. Previous MAC protocols for sensor networks assume static sensor nodes and focus on energy-efficiency. In this paper, we present MMAC, a mobility-adaptive, collision-free MAC protocol for mobile sensor networks. MMAC caters for both weak mobility (e.g. topology changes, node joins and node failures) and strong mobility (e.g. concurrent node joins and failures, and physical mobility of nodes). When using MMAC, nodes are allowed to transmit at particular time-slots, based on the traffic information and mobility pattern of the nodes. Allowing transmission at particular time-slots makes MMAC a scheduling-based protocol, thereby guaranteeing collision avoidance. Simulation results indicate that the performance of MMAC is equivalent to that of TRAMA in static sensor network environments. In sensor networks with mobile nodes or high network dynamics, MMAC outperforms existing MAC protocols, including TRAMA and S-MAC, in terms of energy-efficiency, delay and packet delivery.

Radio irregularity phenomenon is often considered as a shortcoming of wireless sensor networks. In this paper, the radio irregularity is regarded as a benefit of wireless networks. The proposed novel method for human presence detection, applied to the monitoring system for residential energy management, utilizes radio irregularity for an efficient human presence detection which increases user awareness and automates the power control. The method monitors 2.4GHz wireless (Zigbee) smart outlets and the communication signals between them to detect changes of the received signal strength indicator (RSSI) and its variations compared to the expected mean values. The signal strength variation is significantly increased due to human presence within the signal propagation path. By applying the algorithm for principal components analysis to the set of RSSI samples obtained from radio communication links within the detection area, it is possible to recognize a human presence. There is no need for additional presence sensors installation, because the proposed method applied to the smart outlets network is quite satisfactory to extend the entire system with the detection capability. Compared to the conventional sensor networks, the presented solution preserves the pervasiveness of smart energy and smart home systems, high level of sensorial intelligence, simplicity and low installation costs.

Duty cycling is a widely used mechanism in wireless sensor networks (WSNs) to reduce energy consumption due to idle listening, but this mechanism also introduces additional latency in packet delivery. Several schemes have been proposed to mitigate this latency, but they are mainly optimized for light traffic loads. A WSN, however, could often experience bursty and high traffic loads, such as due to broadcast or convergecast traffic. In this paper, we present a new MAC protocol, called Demand Wakeup MAC (DW-MAC), that introduces a new low-overhead scheduling algorithm that allows nodes to wake up on demand during the Sleep period of an operational cycle and ensures that data transmissions do not collide at their intended receivers. This demand wakeup adaptively increases effective channel capacity during an operational cycle as traffic load increases, allowing DW-MAC to achieve low delivery latency under a wide range of traffic loads including both unicast and broadcast traffic. We compare DW-MAC with S-MAC (with and without adaptive listening) and with RMAC using ns-2 and show that DW-MAC outperforms these protocols, with increasing benefits as traffic load increases. For example, under high unicast traffic load, DW-MAC reduces delivery latency by 70% compared to S-MAC and RMAC, and uses only 50% of the energy consumed with S-MAC with adaptive listening. Under broadcast traffic, DW-MAC reduces latency by more than 50% on average while maintaining higher energy efficiency.

Internet of things (IoT) is a revolution of the internet where a group of computing devices, sensors, machines or people, having unique identifiers and the ability to transfer data over the network without human intervention, are interconnected. Opportunistic networks (OppNets) are a type of disruption‐tolerant networks, where network topology is not fixed and the devices are connected intermittently. Opportunistic IOT (OppIoT) is a blend of OppNets and IoT networks, where the data are shared among IoT devices and human communities exploiting the opportunistic contact nature of humans. The data is usually transmitted in a broadcast manner, exposing it to all the members of the network. Thus, securing the data transmitted is of utmost importance in OppIoT. This article proposes a trust‐based schemE (called T_CAFE) for securing the network against several attacks like sybil, bad mouthing, good mouthing, black hole and packet fabrication attacks. Using the opportunistic network environment simulator for performing simulations, it is found that the proposed T_CAFE protocol enhances the network security and outperforms routing protocols such as SHBPR, RSASec and ATDTN in terms of legitimate packet delivery, higher probability of message delivery, lower count of dropped messages and lower value of latency in packet delivery.

A Mobile Ad-hoc Network (MANET) is a collection of autonomous nodes that communicate with each other by forming a multi-hop network without fixed infrastructure using special routing protocols. AODV (Ad hoc On demand Distance Vector) is a reactive routing protocol in which the routes are discovered only when needed. Due to the dynamic nature of MANET the routing procedures are difficult and insecure. The network layer is more vulnerable to attack as it handles all the communication between nodes. Denial-of-Service (DoS) attacks launched by malicious node are one of the most serious threats at network layer. In this paper we proposed new technique to prevent the flooding attack targeting the DoS. This technique can be applicable to all the three phases, that are 'route discovery', 'route maintenance' and 'data transfer'. Our proposed technique is the improvement over AMTT (Avoiding Mistaken Transmission Table). It not only identifies and distinguishes malicious node from the legal node but also reconsider it after giving adequate penalty. By using this scheme the network resources can be utilized in more effective way, the overall network performance will be improved including throughput and increased packet delivery ratio with less delays.

We consider a delay-tolerant network (DTN) whose mobile nodes are assigned to collect packets from data sources and deliver them to a sink (i.e., a gateway). Each mobile node operates by using energy transferred wirelessly from the gateway. For such a network, two main issues are studied. First, when a mobile node is at the data source, this node must decide on whether to accept the packet received from the data source or not. In contrast, whenever a mobile node is at the gateway, it has to decide on whether to transmit the packets collected from the data sources or to request wireless energy transfer. Second, multiple mobile nodes can cooperate and form coalitions to help one another in the delivery of packets from their associated data sources. However, this cooperation may not be always beneficial due to the limited buffer and energy resources. Moreover, some mobile nodes may secretly decide to deviate from a given coalition, thus taking advantage of the other innocent mobile nodes. To address these two issues, this paper introduces a performance analysis and optimization framework, which is based on a joint optimization and game-theoretic framework. The optimization model is used to obtain the packet delivery policy of each individual mobile node. Then, a novel game-theoretic model, namely a repeated coalition formation game , is developed to analyze the cooperation strategies of multiple mobile nodes.