International Journal of Sensors Wireless Communications and Control - Volume 9, Issue 4, 2019

A Wireless Sensor Network (WSN) is an effective sensing technology that is used to replicate the human capability of sensing, collecting, computing, processing and transmitting the data that is collected from a very large area. In recent past, sensor technology has shown tremendous development in the field of environment & health monitoring, military surveillance, vehicle tracking, and detection. The participating sensor nodes are prone to failure because of limited resources. The topology of the networks is highly dynamic in nature because of frequent failure of the sensor nodes. The Quality of Service support to highly dynamic networks is one of the challenging tasks. The dynamic nature, unpredictable topology, the demand of miniature size of the devices, tiny size of sensors and limited resources attract the researchers towards the designing of QoS aware protocols. This paper has discussed the architecture, applications, life cycle and types of WSN. Further, various QoS protocols, their limitations, and challenges have also been discussed. Further, this paper presents the most important open issues and challenges in providing QoSs provisioning to the WSN as QoS routing, energy consumption, bandwidth utilization, security, and mobility. This comprehensive review surely helps the researchers to find the new existing challenges and also help them to design new research problems for their future work.

Recently the Wireless Body Area Network (WBAN) technology has appeared as a subcategory of wireless sensor network (WSN) to improve the quality of life. For such medical system, the improving of reliability becomes very critical research issue because the patient requires continuous monitoring via network. On the other hand, a special attention must be given to the energy consumption because the WBAN nodes must be able to operate for long duration without being recharged or replaced. In this Paper, we have carried out survey of various existing mechanisms, recent techniques and protocols used for reliable communication and energy efficiency under low delay constraints in remote patient monitoring system. This survey depicts that the existing solutions can be further modified to devise more reliable solutions.

Background & Objective: In this paper, a new energy efficient LEACH-based protocol for wireless sensor network is presented. One of the main issues in Wireless Sensor Networks (WSNs) is the battery consumption. In fact, changing batteries is a time consuming task and expensive. It is even impossible in many remote WSNs. Methods: The main goal of the presented protocol is to decrease the energy consumption of each node and increase the network lifetime. Lower power consumption results in longer battery lifetime. This protocol takes the advantage of sub-threshold technique and bee colony algorithm in order to optimize the energy consumption of a WSN. Simulation results show that the energy consumption of the wireless sensor network reduces by 25 percent using STBCP in comparison with recent LEACHbased protocols. It has been shown that the average energy of the network remains balanced and the distribution of residual energy in each round is equitable. Conclusion: In addition, the lifetime of a network using STBCP protocol has been increased by 23 percent regarding recently presented routing protocols.

Background & Objective: In this paper, environmental monitoring system is implemented using a wireless sensor networking (WSN) via a local internet protocol (IP) utilizing Wi-Fi media. For enchanting data, DHT-11 (Temperature and Humidity sensor) and MQ-6 (LPG gas sensor) are being used. Methods: The basic objective of this research is to monitor and to develop a real-time monitoring of humidity and temperature, as well as the availability of gas using the very available DHT-11 sensor, MQ-6 sensor, and ESP-8266 NodeMCU module and then observe the data from a local IP based webpage. Conclusion: This paper also makes a compact distinction between conventional and the local IP based observing system of an environment. The sensor's data are saved in an IP based webpage by which we can monitor the sensor’s data without any access to the internet.

Background: The advent of High Performance Computing (HPC) applications and big data applications has made it imparitive to develop hardware that can match the computing demands. In such high performance systems, the high speed multipliers are the most sought after components. A compressor is an important part of the multiplier; it plays a vital role in the performance of multiplier, also it contributes to the efficiency enhancement of an arithmetic circuit. The 5:2 compressor circuit design proposed here improves overall performance and efficiency of the arithmetic circuits in terms of power consumption, delay and power delay product. The proposed 5:2 compressor circuit was implemented using both CMOS and Carbon Nano Tube Field Effect Transistor (CNTFET) technologies and it was observed that the proposed circuit has yielded better results with CNTFETs as compared to MOSFETs. Methods/Results: The proposed 5:2 compressor circuit was designed with CMOS technology simulated at 45 nm with voltage supply 1.0 V and compared it with the existing 5:2 compressor designes to validate the improvements. Thereafter, the proposed design was implemented with CNTFET technology at 32 nm and simulated with voltage supply 0.6 V. The comparision results of proposed 5:2 compressor with existing designs implemented using CMOS. The results also compare the proposed design on CMOS and CNTFET technologies for parameters like power, delay, power delay product. Conclusion: It can be concluded that the proposed 5:2 compressor gives better results as compared to the existing 5:2 compressor designs implemeted using CMOS. The improvement in power, delay and power delay product is approx 30%, 15% and 40% respectively. The proposed circuit of 5:2 compressor is also implemented using CNTFET technology and compared, which further enhances the results by 30% (power consumption and PDP). Hence, the proposed circuit implemented using CNTFET gives substantial improvements over the existing circuits.

Background: Elastic optical networks can support high data bit rates efficiently with its flexible wavelength grid, and with virtual optical networks, network resources can be managed simply. However, the signal may be deteriorated by the physical impairments. Therefore, service differentiation techniques have to consider the physical impairments. Objective: We propose a novel virtual optical network construction algorithm that provides service differentiation. Moreover, the effect of physical impairments is considered before constructing a virtual optical network. The goal of the proposed algorithm is to provide service differentiation in terms of the rejection rate of virtual optical network requests. Here, we consider the on-line scenario where the traffic is not known in advance. Methods: In the proposed method, each virtual optical network comprises two nodes and a lightpath between the two nodes. In our proposed method, service differentiation is provided by giving a higher (lower) acceptance rate for high (low) priority users. This method consists of four mechanisms; signaling mechanism, physical impairment estimation mechanism, resource check mechanism, and retransmission mechanism. Numerical Results: We evaluate by simulation the performance of the proposed method in NSFNET and European topologies. Analysis of the rejection rate as function of network load, impact of the network load on the number of retransmissions, and impact of network topology were discussed. Numerical results show that our method not only provides service differentiation but also reduces the overall rejection rate. Conclusion: We can conclude that our method is efficient compared to the conventional methods considering the scenario and topologies analyzed.

Background & Objective: The operating efficiency of a sensor network totally relies upon the energy that is consumed by the nodes to perform various tasks like data transmission etc. Thus, it becomes mandatory to consume the energy in an intelligent way so that the network can run for a long period. This paper proposed an energy efficient Cluster Head (CH) selection mechanism by considering the distance to Base Station (BS), distance to node and energy as major factors. The concept of volunteer node is also introduced with an objective to reduce the energy consumption of the CH to transmit data from source to BS. The role of the volunteer node is to transmit the data successfully from source to destination or BS. Conclusion: The results are observed with respect to the Alive nodes, dead nodes and energy consumption of the network. The outcome of the proposed work proves that it outperforms the traditional mechanisms.

Background & Objective: The paper explores a new instrument of computer vision to measure three-dimension deformation with an Internet of Things (IoT) system including Raspberry Pi, digital cameras and OpenCV programs in laboratory and field testing so as to monitor the potential deformation of a structure drainage well in a landslide. Methods: A chessboard pattern is detected in the image by the camera so that pixels of chessboard cornors can be recognized by OpenCV programs. X-direction, Y-direction and Z-distance changes can be casulated by the similar triangles relationship of camera pixels. For laboratory testing, standard deviations of the measurement were approximately 0.01 cm. Results: For field testing, the study installed four sets of Raspberry Pi in a drainage well within a landslide and employed OpenCV programs to interpret pixel changes of chessboards at four levels of the draiage well. Conclusion: Overall, the instrument can be employed for triaxial deformation monitoring of the construction in the field effectively and automatically.

Background & Objective: Speaker Recognition (SR) techniques have been developed into a relatively mature status over the past few decades through development work. Existing methods typically use robust features extracted from clean speech signals, and therefore in idealized conditions can achieve very high recognition accuracy. For critical applications, such as security and forensics, robustness and reliability of the system are crucial. Methods: The background noise and reverberation as often occur in many real-world applications are known to compromise recognition performance. To improve the performance of speaker verification systems, an effective and robust technique is proposed to extract features for speech processing, capable of operating in the clean and noisy condition. Mel Frequency Cepstrum Coefficients (MFCCs) and Gammatone Frequency Cepstral Coefficients (GFCC) are the mature techniques and the most common features, which are used for speaker recognition. MFCCs are calculated from the log energies in frequency bands distributed over a mel scale. While GFCC has been acquired from a bank of Gammatone filters, which was originally suggested to model human cochlear filtering. This paper investigates the performance of GFCC and the conventional MFCC feature in clean and noisy conditions. The effects of the Signal-to-Noise Ratio (SNR) and language mismatch on the system performance have been taken into account in this work. Conclusion: Experimental results have shown significant improvement in system performance in terms of reduced equal error rate and detection error trade-off. Performance in terms of recognition rates under various types of noise, various Signal-to-Noise Ratios (SNRs) was quantified via simulation. Results of the study are also presented and discussed.

Background and Objective: Mobile Wireless Sensor Network (MWSN) is a specialized wireless network made up of large number of mobile sensors, where each sensor is capable of changing its location, relaying data to either the base station or neighbouring nodes. MWSN has emerged as a useful integral part of modern communication systems; however, its major performance challenges are lack of data delivery assurance due to mobility of its sensors, low computational power of its nodes, and some security related issues. Methods: Most of the existing WSN routing protocols are for non-mobile sensors and require considerably high computational power. Thus, not suitable for energy-constraint WSN with mobile sensors. Therefore, there is need for a secure protocol for MWSN with mechanisms that take into account the limited resources of the nodes and dynamism of its nodes’ locations. Results: In this paper, an efficient routing protocol for MWSN is proposed, not to only improve data delivery but to ensure reliability. This protocol is capable of selecting optimal multi-hop route among available routes for the source node and securely hops the data to the destination nodes through intermediary nodes. Formal and informal security analysis of the routing protocol is done to ascertain the required security level of the protocol. In addition, computational cost analysis is done to evaluate the computational cost of the protocol. Conclusion: The analysis results showed that the proposed protocol was secure and required low computational cost

Background & Objective: Harmonic amplification is one of the primary issues in power system networks. The objective of this study is to manage the harmonic event and its significant effects on power quality. A new control approach that uses Artificial Intelligence (AI) is proposed and applied to a Distribution Static Synchronous Compensator (DSTATCOM). DSTATCOM is a FACTS device that can achieve highly effective reactive power compensation to reduce and/or damp the harmonic amplification in power system networks. Results & Conclusion: Simulation results are obtained using the MATLAB/Simulink package. The validity and effectiveness of using the AI approach are proven based on the DSTATCOM FACTs device with linear and nonlinear loads. Analysis results are discussed.