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1 – 10 of over 35000Hanisah Mohd Zali, Mohd Khairil Adzhar Mahmood, Idnin Pasya, Miyuki Hirose and Nurulazlina Ramli
Utilization of electromagnetic wave (EMW) sensors in an underwater environment has the potential to increase the data rate compared to acoustic-based sensors because of the…
Abstract
Purpose
Utilization of electromagnetic wave (EMW) sensors in an underwater environment has the potential to increase the data rate compared to acoustic-based sensors because of the ability to use larger signal bandwidth. Nevertheless, EMW signals has the drawback of large signal attenuation in underwater, attributed to the high relative permittivity and conductivity of water compared to the atmosphere, hence employment of wide signal bandwidth is necessary to balance the data rate-attenuation trade-off. The purpose of this paper is to analyze the characteristics of both narrowband and wideband EMW signal propagation underwater and devise a path loss model for both cases.
Design/methodology/approach
Path loss measurement was conducted using a point-to-point configuration in a laboratory water tank while transmitting narrowband and wideband signals between a pair of wideband underwater antennas. The wideband underwater antennas use buffer-layer structures as the impedance matching layer to optimize the antenna performance when operating underwater. The path loss for narrowband signal was modeled using a multi-layer propagation equation in lossy medium considering losses at the medium boundaries. For the case of the wideband signal, a modified version of the model introducing power integration over bandwidth is adopted. These models were formulated through numerical simulations and verified by measurements.
Findings
The measured narrowband path loss marked an 80 dB attenuation using 800 MHz at 2 m distance. The proposed narrowband model agrees well with the measurements, with approximately 3 dB modeling error. Utilization of the proposed wideband path loss model resulted in a reduction of the gradient of the path loss curve compared to the case of the narrowband signal. The measured wideband path loss at 2 m distance underwater was approximately −65 dB, which has been shown to enable a working signal-to-noise ratio of 15 dB. This proves the potential of realizing high data rate transmission using the wideband signal.
Originality/value
The paper proposed a wideband propagation model for an underwater EMW sensor network, using power integration over bandwidth. The effectiveness of using wideband EMW signals in reducing path loss is highlighted, which is seldom discussed in the literature. This result will be of useful reference for using wideband signals in designing a high data rate transmission system in underwater wireless sensor networks, for example, in link budget, performance estimation and parameter design of suitable transmission scheme.
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Nandakishor Sirdeshpande and Vishwanath Udupi
Wireless communication channel provides a wide area of applications in the field of communication, distributed sensor network and so on. The prominence of the wireless…
Abstract
Purpose
Wireless communication channel provides a wide area of applications in the field of communication, distributed sensor network and so on. The prominence of the wireless communication channel is because of its robust nature and the sustainability for the precise ranging and the localization. The precision and accuracy of the wireless communication channel largely depend on the localization. The development of the wireless communication channel with improved benefits needs the accurate channel model.
Design/methodology/approach
This paper characterizes the tangential path loss model in the WINNER based wireless communication channel model. The measurements taken in the WINNER channel model are compared with the tangential path loss characterized WINNER Channel model.
Findings
The model operates well over the varying antenna orientations, measurement condition and the propagation condition. The proposed tangential path loss model is performing well over the various outdoor scenarios.
Originality/value
The proposed characterization shows change in the small-scale parameters (SSP), such as power, delay, angle of arrival and angle of departure as well as the large-scale parameters (LSP), such as RMS delay spread, shadowing, path loss and Ricean factor associated with the model.
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Dinesh Kumar Anguraj, Abul Bashar, R. Nidhya, P.K. Shimna and Renjith V. Ravi
The purpose of this paper is energy consumption and security. To extend the sensor’s life span, saving the energy in a sensor is important. In this paper, biosensors are implanted…
Abstract
Purpose
The purpose of this paper is energy consumption and security. To extend the sensor’s life span, saving the energy in a sensor is important. In this paper, biosensors are implanted or suited on the human body, and then, transposition has been applied for biosensors for reducing the sensor distance from the sink node. After transposition path loss has been calculated, security is maintained and also compared the results with the existing strategies.
Design/methodology/approach
Nowadays, one of the most emergent technologies is wireless body area network (WBAN), which represents to improve the quality of life and also allow for monitoring the remote patient and other health-care applications. Traffic routing plays a main role together with the relay nodes, which is used to collect the biosensor’s information and send it towards the sink.
Findings
To calculate the distance and observe the position, Euclidean distance technique is used. Path loss is the main parameter, which is needed to reduce for making better data transmission and to make the network stability. Routing protocols can be designed, with the help of proposed values of sensors locations in the human body, which gives good stability of network and lifetime. It helps to achieve as the less deplete energy.
Originality/value
This scheme is compared with the two existing schemes and shows the result in terms of parameter path loss. Moreover, this paper evaluated a new method for improving the security in WBAN. The main goal of this research is to find the optimal sensor location on the body and select the biosensor positions where they can get less energy while transmitting the data to the sink node, increasing the life span in biosensors, decreasing memory space, giving security, controlling the packet complexity and buffer overflow and also fixing the damages in the existing system.
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The purpose of this paper is to review the existing routing algorithms for wireless ad hoc networks to evaluate the methods according to the current requirements. Wireless ad hoc…
Abstract
Purpose
The purpose of this paper is to review the existing routing algorithms for wireless ad hoc networks to evaluate the methods according to the current requirements. Wireless ad hoc network can provide communication in emergency situations. Active nodes in ad hoc network work as sender, receiver and router at the same time. Nodes are equipped with limited bandwidth and energy. Optimal routing method can help in “smart use” of available resources. Evolvement of routing method based on need is a continuous process. Numerous applications of ad hoc network motivates researcher for further development to fulfill the need of society.
Design/methodology/approach
In this paper, routing algorithms for ad hoc network based on ant colony optimization, multipath routing and with multiple input multiple output (MIMO) antenna support have been discussed.
Findings
Comparative analysis has been drawn among existing algorithms of different categories. Transmitting message packets parallel through multiple paths in the network can save overall resource usage in the network.
Originality/value
The authors have discussed the future area of development for optimal routing in ad hoc networks. Considering signal noise ratio and congestion status while selecting path can provide better energy use in the network. Rather than leaving less prioritized route paths, multiple paths can be used for sending data packets parallel.
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Mohammad Makhdoumi Akram, Alireza Nikfarjam, Hassan Hajghassem, Mohammad Ramezannezhad and Massoud Iraj
The importance of Carbon dioxide (CO2) gas detection as a greenhouse and exhale breathe gas is an undeniable issue. This study aims to propose a new miniaturized, low cost and…
Abstract
Purpose
The importance of Carbon dioxide (CO2) gas detection as a greenhouse and exhale breathe gas is an undeniable issue. This study aims to propose a new miniaturized, low cost and portable no dispersive infrared (NDIR) system for detecting CO2 gas.
Design/methodology/approach
Poly(methyl methacrylate) (PMMA)-based channels with Au coating because of its high reflection properties in IR region were used in this work. The optical windows were fabricated using PDMS polymer which is cost effective and novel in comparison to other conventional methods. The effects of channel dimensions, lengths and entrance angle of light on optical path length and losses were analyzed with four types of channel using both simulation and experimental tests.
Findings
The simulation results indicate that the 0 degree light entrance angle is the most efficient angle among different investigated conditions. The experimental data are in agreement with the simulation results regarding the loss and optical path length in different types of channel. The experimental tests were performed for the 0.5% up to 20% of CO2 concentration under constant temperature and humidity condition. The results show that the device with 5 and 2 cm channels length were saturated in 4% and 8% concentration of CO2 gas, respectively. Response and recovery times were depending on gas concentration and channels specifications that in average found to be 10 S and 14 S, respectively, for the largest size channel. Moreover, the environment humidity effect on detection system performance was investigated which had no considerable influence. Also, the saturation fraction absorbance value for devices with various dimensions were 0.62 and 0.8, respectively.
Practical implications
According to the performed curve fitting for practical situation and selected CO2 concentration range for experimental tests, the device is useful for medical and environmental applications.
Originality/value
PMMA with Au deposition layer was used as a basic material for this NDIR system. Besides, a novel PDMS optical window helps to have a low cost device. The effects of channel dimensions, lengths and entrance angle of light on optical path length and losses were analyzed using both simulation and experimental tests. Using narrowband optical filter (100 nm bandwidth) helps to have a system with good CO2 selectivity. In addition, experimental tests with different channel dimensions and lengths covered a considerable range of CO2 concentration useful for medical and environmental applications. Finally, curve fitting was adopted for a modified Beer–Lambert law as a practical situation.
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Kate A. Remley, Galen Koepke, Chris Holloway, Dennis Camell and Chriss Grosvenor
The purpose of this paper is to describe common methods for evaluating the performance of wireless devices such as wireless sensors in harsh radio environments.
Abstract
Purpose
The purpose of this paper is to describe common methods for evaluating the performance of wireless devices such as wireless sensors in harsh radio environments.
Design/methodology/approach
The paper describes how measurements of real‐world propagation environments can be used to support the evaluation process, then presents representative measurement data from multipath environments where sensor networks are likely to be deployed: a fixed‐infrastructure, process‐control environment (here an oil refinery), and a heavy industrial environment (here an automotive assembly plant).
Findings
Results on the characterization of multipath in the propagation channel are summarized and how these results may be used in the performance evaluation of sensor networks is discussed.
Originality/value
The paper describes measurement results from environments where little open‐literature data exists on point‐to‐point propagation, specifically high‐multipath environments. These highly reflective scenarios can present difficulties for deployment of sensor networks.
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D.S. Vohra, Pradeep Kumar Garg and Sanjay Ghosh
The purpose is to derive the most effective place in the air for an aerial robot, viz., drone to use as an alternative communication system during disasters.
Abstract
Purpose
The purpose is to derive the most effective place in the air for an aerial robot, viz., drone to use as an alternative communication system during disasters.
Design/methodology/approach
In this technology-driven era, various concepts are becoming the area of interest for multiple researchers. Drone technology is also one of them. The researchers, with interest in drones, are therefore trying to understand the various uses of employing drones in diverse applications which are mind-boggling, starting from civil applications (viz., an inspection of power lines, counting wildlife, delivering medical supplies to inaccessible regions, forest fire detection, and landslide measurement) to military applications (viz., real-time monitoring, surveillance, patrolling, and demining). However, one area where its usage is still to be exploited in many countries is using drones as a relay when communication lines are disrupted due to natural calamities. This will be particularly helpful in rescuing the affected people as the aerial node will enable them to communicate to the rescue team using mobiles/ordinary landline telephones even when regular communication towers are destroyed due to disastrous natural calamities, for example, tsunamis, earthquakes, and floods. Various algorithms, namely, water filling algorithm, advanced water filling algorithm, equal power distribution algorithm, and particle swarm optimization, were therefore studied and analyzed using simulation in addition to various path loss models to realize the desired place for an aerial robot, viz., drone in the air, which will eventually be used as an alternative communication system for badly hit ground users due to any disaster.
Findings
It was found that the effective combination of the water filling algorithm and particle swarm optimization algorithm may be done to place the drone in the air to increase the overall throughput of the affected ground users.
Originality/value
The research is original. None of the parts of this research paper has been published anywhere.
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Ch Rajendra Prasad and Polaiah Bojja
This paper aims to present a non-linear mathematical model-based routing protocol for wireless body area networks (WBANs). Two non-linear mathematical models for WBANs are used in…
Abstract
Purpose
This paper aims to present a non-linear mathematical model-based routing protocol for wireless body area networks (WBANs). Two non-linear mathematical models for WBANs are used in the proposed protocols Model 1 and Model 2. Model 1 intends to improve the data transmission rate and Model 2 intends to reduce energy consumption in the WBANs. These models are simulated for fixed deployment and priority-based data transmission, and performance of the network is analyzed under four constraints on WBANs.
Design/methodology/approach
Advancements in wireless technology play a vital role in several applications such as electronic health care, entertainment and games. Though WBANs are widely used in digital health care, they have restricted battery capacity which affects network stability and data transmission. Therefore, several research studies focused on reducing energy consumption and maximizing the data transmission rate in WBANs.
Findings
Simulation results of the proposed protocol exhibit superior performance in terms of four network constraints such as residual energy, the stability of the network, path loss and data transmission rate in contrast with conventional routing protocols. The performance improvement of these parameters confirms that the proposed algorithm is more reliable and consumes less energy than traditional algorithms.
Originality/value
The Model 1 of the proposed work provides maximum data extraction, which ensures reliable data transmission in WBANs. The Model 2 allocates minimal hop count path between the sink and the sensor nodes, which minimizes energy consumption in the WBANs.
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Xianmiao Li, Zhenting Xu and Yuqin Hu
This study aims to explore the dual-path effects of challenge (CTP) and hindrance time pressure (HTP) on knowledge sharing, which provides theoretical reference for knowledge…
Abstract
Purpose
This study aims to explore the dual-path effects of challenge (CTP) and hindrance time pressure (HTP) on knowledge sharing, which provides theoretical reference for knowledge teams to carry out knowledge sharing smoothly.
Design/methodology/approach
This study collected two waves of data and surveyed 416 employees in China. Regression analysis, bootstrapping and structure equitation modeling was adopted to test the hypotheses.
Findings
CTP has a positive impact on employee knowledge sharing, while HTP has a negative impact on employee knowledge sharing. Self-efficacy plays a mediating role between CTP and knowledge sharing, and emotional exhaustion plays a mediating role between HTP and knowledge sharing. The perceived organizational support can moderate the relationship between CTP and self-efficacy and between HTP and emotional exhaustion.
Originality/value
This study explains the reasons for the academic controversy about the effect of time pressure, enhances the scholars’ attention and understanding of the dual-path mechanism between time pressure and knowledge sharing and augments the theoretical research of time pressure and knowledge sharing.
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Silvanus Teneng Kiyang and Robert Van Zyl
The purpose of this work is to assess the influence of ambient noise on the performance of wireless sensor networks (WSNs) empirically and, based on these findings, develop a…
Abstract
Purpose
The purpose of this work is to assess the influence of ambient noise on the performance of wireless sensor networks (WSNs) empirically and, based on these findings, develop a mathematical tool to assist technicians to determine the maximum inter-node separation before deploying a new WSN.
Design/methodology/approach
A WSN test platform is set up in an electromagnetically shielded environment (RF chamber) to accurately control and quantify the ambient noise level. The test platform is subsequently placed in an operational laboratory to record network performance in typical unshielded spaces. Results from the RF chamber and the real-life environments are analysed.
Findings
A minimum signal-to-noise ratio (SNR) at which the network still functions was found to be of the order 30 dB. In the real-life scenarios (machines, telecommunications and computer laboratories), the measured SNR exceeded this minimum value by more than 20 dB. This is due to the low ambient industrial noise levels observed in the 2.4 GHz ISM band for typical environments found at academic institutions. It, therefore, suggests that WSNs are less prone to industrial interferences than anticipated.
Originality/value
A predictive mathematical tool is developed that can be used by technicians to determine the maximum inter-node separation before the WSN is deployed. The tool yields reliable results and promises to save installation time.
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