A survey on MAC-based physical layer security over wireless sensor network

Physical layer security for wireless sensor networks (WSNs) is a laborious and highly critical issue in the world. Wireless sensor networks have great importance in civil and military fields or applications. Security of data/information through wireless medium remains a challenge. The data that we transmit wirelessly has increased the speed of transmission rate. In physical layer security, the data transfer between source and destination is not confidential, and thus the user has privacy issues, which is why improving the security of wireless sensor networks is a prime concern. The loss of physical security causes a great threat to a network. We have various techniques to resolve these issues, such as interference, noise, fading in the communications, etc. In this paper we have surveyed the different parameters of a security design model to highlight the vulnerabilities. Further we have discussed the various attacks on different layers of the TCP/IP model along with their mitigation techniques. We also elaborated on the applications of WSNs in healthcare, military information integration, oil and gas. Finally, we have proposed a solution to enhance the security of WSNs by adopting the alpha method and handshake mechanism with encryption and decryption

Fostering coastal resilience to climate change vulnerability in Bangladesh, Brazil, Cameroon and Uruguay: a cross-country comparison

© 2017, Springer Science+Business Media B.V. This paper describes a comparative study of four different cases on vulnerability, hazards and adaptive capacity to climate threats in coastal areas and communities in four developing countries: Bangladesh, Brazil, Cameroon and Uruguay. Coastal areas are vulnerable to sea-level rise (SLR), storm surges and flooding due to their (i) exposure, (ii) concentration of settlements, many of which occupied by less advantaged groups and (iii) the concentration of assets and services seen in these areas. The objective of the paper is twofold: (i) to evaluate current evidence of coastal vulnerability and adaptive capacity and (ii) to compare adaptation strategies being implemented in a sample of developing countries, focusing on successful ones. The followed approach for the case evaluation is based on (i) documenting observed threats and damages, (ii) using indicators of physical and socioeconomic vulnerability and adaptive capacity status and (iii) selecting examples of successful responses. Major conclusions based on cross-case comparison are (a) the studied countries show different vulnerability, adaptive capacity and implementation of responses, (b) innovative community-based (CBA) and ecosystem-based adaptation (EbA) and (c) early warning systems are key approaches and tools to foster climate resilience. A recommendation to foster the resilience of coastal communities and services is that efforts in innovative adaptation strategies to sea-level rise should be intensified and integrated with climate risk management within the national adaption plans (NAPAs) in order to reduce the impacts of hazards

Cluster Based Distance Sequence Distance Vector Routing Protocols for Mobile Ad-hoc Network

Mobile Ad-hoc Network is a self-organizing and self-configuring network that has mobile nodes connected wirelessly to each other. Transmission of data packets takes place through single or multi-hop in MANET. Each node in the MANET acts as a router and a host device. MANET is a scalable network and can accommodate nodes to a great extent. However, due to the increase in traffic, it may occur congestion in mobile ad-hoc network. Congestion is a major issue for end to end delay and network overhead. The clustering technique is used to virtually divide the MANET in groups, which allows the data to divide in groups as well. Clustering technique is more efficient than the existing standard protocols used for routing. Such fundamental (DSDV) protocol leads to routing overhead in scalable MANET. In this work, we presented a cluster-based technique for DSDV (Distance Sequence Distance Vector) routing protocol to overcome routing overhead, reduce the packet size and utilize the bandwidth in a large network. Three steps are defined for the cluster based on DSDV, which are the cluster head selection, cluster formation and routing of packets. The cluster based on DSDV (CDSDV) is a Clustering technique to overcome the production of excessive information. Since, the algorithms are made in a manner that the nodes are required to share routing information inside the cluster instead of the entire network. Hence, the results of the CDSDV demonstrate about 10 to 15 percent improvement for throughput and Packet Delivery Ratio, while the average end to end delay seems to be degraded by a considerable degree because of the mutual communication of the cluster heads. The energy consumption of CDSDV is inadequate as it utilizes a slightly more energy than the standard DSDV

An approach to estimate spatial distribution of analyte within cells using spectrally-resolved fluorescence microscopy

While fluorescence microscopy has become an essential tool amongst chemists and biologists for the detection of various analyte within cellular environments, non-uniform spatial distribution of sensors within cells often restricts extraction of reliable information on relative abundance of analytes in different subcellular regions. As an alternative to existing sensing methodologies such as ratiometric or FRET imaging, where relative proportion of analyte with respect to the sensor can be obtained within cells, we propose a methodology using spectrally-resolved fluorescence microscopy, via which both the relative abundance of sensor as well as their relative proportion with respect to the analyte can be simultaneously extracted for local subcellular regions. This method is exemplified using a BODIPY sensor, capable of detecting mercury ions within cellular environments, characterized by spectral blue-shift and concurrent enhancement of emission intensity. Spectral emission envelopes collected from sub-microscopic regions allowed us to compare the shift in transition energies as well as integrated emission intensities within various intracellular regions. Construction of a 2D scatter plot using spectral shifts and emission intensities, which depend on the relative amount of analyte with respect to sensor and the approximate local amounts of the probe, respectively, enabled qualitative extraction of relative abundance of analyte in various local regions within a single cell as well as amongst different cells. Although the comparisons remain semi-quantitative, this approach involving analysis of multiple spectral parameters opens up an alternative way to extract spatial distribution of analyte in heterogeneous systems. The proposed method would be especially relevant for fluorescent probes that undergo relatively nominal shift in transition energies compared to their emission bandwidths, which often restricts their usage for quantitative ratiometric imaging in cellular media due to strong cross-talk between energetically separated detection channels