Pareto-optimal clustering scheme using data aggregation for wireless sensor networks

The presence of cluster heads (CHs) in a clustered wireless sensor network (WSN) leads to improved data aggregation and enhanced network lifetime. Thus, the selection of appropriate CHs in WSNs is a challenging task, which needs to be addressed. A multicriterion decision-making approach for the selection of CHs is presented using Pareto-optimal theory and technique for order preference by similarity to ideal solution (TOPSIS) methods. CHs are selected using three criteria including energy, cluster density and distance from the sink. The overall network lifetime in this method with 50% data aggregation after simulations is 81% higher than that of distributed hierarchical agglomerative clustering in similar environment and with same set of parameters. Optimum number of clusters is estimated using TOPSIS technique and found to be 9–11 for effective energy usage in WSNs.     

RLProph: a dynamic programming based reinforcement learning approach for optimal routing in opportunistic IoT networks

Wireless Networks - Routing in Opportunistic Internet of Things networks (OppIoTs) is a challenging task because of intermittent connectivity between devices and the lack of a fixed path between...     

A Nonbactericidal Zinc‐Complexing Ligand as a Biofilm Inhibitor: Structure‐Guided Contrasting Effects on Staphylococcus aureus Biofilm

Zinc‐complexing ligands are prospective anti‐biofilm agents because of the pivotal role of zinc in the formation of Staphylococcus aureus biofilm. Accordingly, the potential of a thiosemicarbazone (compound C1) and a benzothiazole‐based ligand (compound C4) in the prevention of S. aureus biofilm formation was assessed. Compound C1 displayed a bimodal activity, hindering biofilm formation only at low concentrations and promoting biofilm growth at higher concentrations. In the case of C4, a dose‐dependent inhibition of S. aureus biofilm growth was observed. Atomic force microscopy analysis suggested that at higher concentrations C1 formed globular aggregates, which perhaps formed a substratum that favored adhesion of cells and biofilm formation. In the case of C4, zinc supplementation experiments validated zinc complexation as a plausible mechanism of inhibition of S. aureus biofilm. Interestingly, C4 was nontoxic to cultured HeLa cells and thus has promise as a therapeutic anti‐biofilm agent. The essential understanding of the structure‐driven implications of zinc‐complexing ligands acquired in this study might assist future screening regimes for identification of potent anti‐biofilm agents.     

A comprehensive four-stage framework for evaluation of Information Communication Technologies for Development interventions

ABSTRACT

In spite of almost three decades of efforts in the domain of Information Communication Technologies for Development (ICTD), the validity and effectiveness of the relationship between ICT and D (Development) are not clear, perhaps due to a lack of a comprehensive framework for evaluating ICTD interventions. Comprehensive evaluation of ICTD interventions is, however, difficult as its outcomes are often intangible in nature. The aim of this paper is to develop a comprehensive evaluation framework for ICTD interventions with a specific focus on “D” aspects of these interventions. This work does not focus only on “impact” evaluation of ICTD interventions but also considers other key aspects of project life cycle in the evaluation process. To develop this framework, we draw inspirations from the domains of “program evaluation” and “IS evaluation” and further refine it with learnings from previous ICTD studies. The result of this exercise is a four-stage framework with each stage containing details of assessment points and key considerations that need to be covered in the context of an ICTD intervention. The framework is then validated using an existing case study drawn from the ICTD literature. The applicability and benefits of the framework are then discussed in the light of this case study.     

Nanoporous Silicon Microcavity Based Fuel Adulteration Sensor

Fuel adulteration is a very common practice in several countries around the world. This paper reports the use of porous silicon as a sensor for the detection of adulteration of petrol and diesel by kerosene. Porous silicon has some very useful properties such as high sensitivity, small size, high surface-to-volume ratio, bio-compatibility and compatibility with silicon IC technology which make it suitable for sensing purposes. The main objective of this work is to develop an optical sensor to detect the level of adulteration in a fuel sample using a porous silicon microcavity (PSMC). Reflectance measurements are used to detect the concentration of kerosene, which is the most commonly used adulterant for petrol and diesel, in the fuel sample. The core principle on which the sensing is based is that a change in the effective refractive index of the microstructure due to the introduction of the fuel in the pores leads to a change in the reflectance spectrum of the structure. The same sensor is used for the detection of adulteration in petrol as well as in diesel. The sensing process is reversible, thus making the sensor reusable.     

A fuzzy logic and game theory based adaptive approach for securing opportunistic networks against black hole attacks

Opportunistic networks (OppNets) are networks that can be used in situations of sparse network connectivity. Strategies for implementing secure transmission of messages in OppNets offer complex and distinctive problems that are wholly different from traditional networks using TCP/IP protocols for data transmission. In this paper, a security protocol named FuzzyPT is proposed which combats black hole attacks in OppNets. The defense mechanism is based on the information extracted from messages in the buffer, potential threat (PT) messages, and fuzzy logic. Fuzziness aids the system in being adaptive by modeling the character of nodes as either benign or malicious. It provides the network with the ability to judge the character of nodes based on relationships between different parameters instead of basing this decision on fixed conditions. FuzzyPT is observed to reduce erroneous decision‐making and decrease the number of false positives and false negatives in the system. An evolutionary game theoretic model is applied, which analyzes the decision‐making ability of relays in choosing varied strategies while forwarding messages. The evolutionary stable state is computed for the protocol, which verifies the proposition that a majority of the relays will cooperate by forwarding messages. The efficiency of the protocol is judged on various grounds such as delivery probability, network overhead ratio, packets dropped, and transmission latency. It is observed that the proposed game theoretic protocol outperforms an existing acknowledge and evolutionary game theory–based security protocol in terms of all the aforementioned performance characteristics.