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Constrained Application Protocol (CoAP) is a communication protocol at application layer in the Internet of things (IoT). It employs NSTART parameter to maintain outstanding parallel connections toward individual destinations for data transfer. In the existing implementation of CoAP, the value for NSTART is defined statically. Where the higher values of this parameter up to a threshold give better throughput in moderate traffic, the lower values for the same control the congestion in overload situations. In overload situations, higher values of NSTART result in increased overhead and thereby perform poorly in terms of throughput. The static nature of the parameter and its relevant performance issues demand to manage NSTART dynamically in CoAP. In this work, we propose an algorithm to adjust the value of NSTART dynamically based on the congestion in the network. The proposed approach is an attempt to make the client free from managing NSTART dynamically. For the proof of concept, we implement and run simulations on Cooja mote at IoT/FIT-Lab testbed and Californium CoAP client. The results show 15% improvement in throughput, 15% reduction in average exchange duration, and 48% reduction in average number of retries (average taken of three scenarios) by proposed approach in comparison with the best case of CoCoA (NSTART = 4).

A common practice in the Internet of Things (IoT) is to integrate the Constrained Application Protocol (CoAP), a lightweight application layer protocol based on UDP (User Datagram Protocol), in its architecture. While UDP does not have any provision to control congestion at the transport layer, CoAP and its other variants, such as CoCoA and CoCoA+, get around this issue by employing their own congestion control mechanism, a send-rate-based congestion control technique, at the application layer. These techniques estimate the send-rate through Round Trip Time (RTT), however, fail to map acknowledgments and re-transmitted messages, leading to inaccurate RTT in case of bursty traffic and thus performs poorly. To tackle this problem, the article proposes novel a technique to regulate the send-rate considering the current and previous congestion ratio, congestion factor, and throughput. The proposed method aims to regulate the send-rate according to congestion level in the network. The performance measurements of the proposed approach show significant increments in goodput and fairness as compared to the techniques used in CoCoA+ and CoAP in burst traffic scenarios.

Internet of Things (IoT) networks are the type of Low Power and Lossy Networks. Routing protocol for Low Power and Lossy Networks (RPL) is the standard routing protocol for IoT network. RPL uses the Destination Oriented Directed Acyclic Graph (DODAG) to get route from source to destination. DODAG formation is based on different objective functions which optimize various routing metrics to get reliable and more optimized path. Objective function Zero (OF0) which is based on minimum hop count method and Minimum Rank with Hysteresis Objective Function (MRHOF) which optimize one routing metric i.e. Expected Transmission Count (ETX) or energy are standard objective functions defined by Internet Engineering Task Force (IETF). Different routing metrics are combined so far as use of single routing metric by RPL doesn’t fulfil overall routing performance requirements. This research proposes a new modified MRHOF objective function which is modification in standard objective function MRHOF. Modified MRHOF objective function uses and optimizes three routing metrics i.e. ETX, Energy and Delay. Implementation of proposed work is done on Cooja Simulator on Contiki OS. Performance evaluation of proposed objective function is done on the basis of these parameters- Packet Delivery Ratio (PDR), Average Power Consumption and Throughput and results show that proposed objective function performs better than other objective functions -0F0 and MRHOF in terms of these parameters.

Internet of things (IoT) is the disruptive technology used in the computer automaton. Embedded electronic hardware is connected to Internet in IoT. Connecting IoT devices to the Internet, IoT security becomes the important issue. In this paper, we explain the recent case studies of attacks on IoT devices and network along with vulnerabilities behind each attack. We enlist reasons behind these attacks along with preventive measures to make the IoT devices and network more secure. The paper aims to attract attention of research community toward IoT security.

In this article, the authors have discussed about the connection between Internet of Things and growth of big data. They have also discussed short reference on the evolution, features, lifecycle, and implementation of Big Data from IoT over the cloud. Internet of Things represents a platform or environment that consists of enormous number of sensors and mediators interconnecting heterogeneous physical devices over the internet. IoT applications are available in many real-world areas such as smart city, smart workplace, smart home, smart transportation and various other ubiquitous computing areas. Using IoT applications generates tremendous amount of data for storage and management in the internet. With the time and research evolution integration of the IoT platforms and cloud comes in the market and IoT platforms data storage and management started shifting to the cloud from the internet connected physical systems for many real-world application areas. Meanwhile when this data becomes huge termed as Big Data. Handling of Big Data over the cloud develops many new areas of research and attention.

Part of speech (POS) cataloguing is the process of allocating the part of speech tag or other philological class sign to each and every word in a sentence. In many Natural Language Processing presentations such as word intellect disambiguation, information recovery, information handling, analyzing, interrogating, and machine interpretation, POS tagging is reflected as the one of the basic obligatory tool. Categorizing the uncertainties in language philological items is the puzzling objective in the procedure of emerging an effectual and correct POS Tagger. Works survey displays that, for Indian lingoes, POS taggers were established only in Hindi, Punjabi, Bengali and Dravidian languages. Some POS taggers were also established generic to the Hindi, Telugu and Bengali tongues. All scheduled POS taggers were grounded on diverse Tag-set, established by diverse organization and individuals. This paper speaks the various developments in POS-taggers and POS-tag-set for Indian language, which is very essential computational verbal tool needed for many natural language processing (NLP) presentation [15].

Mobile communication has various important issues such as congestion control, scarcity of radio spectrum, bandwidth utilization, and security. With increased number of threats in mobile devices, security has become the most important issue now-a-days. Security can be considered primarily at two levels; wireless transmission medium and mobile data level, where malicious applications execute their behavior by exploiting vulnerabilities present in mobile OS. The chapter also focuses on the latter one as these attacks can be easily performed by targeting vulnerabilities present in OS. The content is specifically on Android Operating System security as Android has become the largest installed base of mobile platform. This chapter specifies these vulnerabilities and focuses on malicious intentions of latest and sophisticated malware in detail. The chapter covers static and dynamic analysis tools as well as focuses on limitations of these methods for analyses. The results for malware samples with emulator detection capabilities show that these malware behaves more as benign samples.

The basic purpose of wireless sensor network is to optimize residual energy of nodes and extend the life-time of network. This paper provides an improved algorithm for cluster head selection by reducing network overhead on clusters and transmits the data from source to sink through expanding nodes' life-time. This paper provides method for transmitting data by dividing nodes into different levels in hierarchical format.