Sweta Jain

Crystal Structure of Malaria Parasite Nucleosome Assembly Protein DISTINCT MODES OF PROTEIN LOCALIZATION AND HISTONE RECOGNITION

Nucleosome assembly proteins (NAPs) are histone chaperones that are essential for the transfer and incorporation of histones into nucleosomes. NAPs participate in assembly and disassembly of nucleosomes and in chromatin structure organization. Human malaria parasite Plasmodium falciparum contains two nucleosome assembly proteins termed PfNapL and PfNapS. To gain structural insights into the mechanism of NAPs, we have determined and analyzed the crystal structure of PfNapL at 2.3 Å resolution. PfNapL, an ortholog of eukaryotic NAPs, is dimeric in nature and adopts a characteristic fold seen previously for yeast NAP-1 and Vps75 and for human SET/TAF-1b (β)/INHAT. The PfNapL monomer is comprised of domain I, containing a dimerization α-helix, and a domain II, composed of α-helices and a β-subdomain. Structural comparisons reveal that the “accessory domain,” which is inserted between the domain I and domain II in yeast NAP-1 and other eukaryotic NAPs, is surprisingly absent in PfNapL. Expression of green fluorescent protein-tagged PfNapL confirmed its exclusive localization to the parasite cytoplasm. Attempts to disrupt the PfNapL gene were not successful, indicating its essential role for the malaria parasite. A detailed analysis of PfNapL structure suggests unique histone binding properties. The crucial structural differences observed between parasite and yeast NAPs shed light on possible new modes of histone recognition by nucleosome assembly proteins.

Node stability based clustering algorithm for mobile ad hoc networks

Node mobility is an important factor at the time of clustering in ad hoc network because it directly affects the stability of cluster. In the proposed work a distributed clustering algorithm which uses node mobility as a main concern with battery power and connectivity in terms of no. of neighbouring nodes for selecting cluster heads to achieve better stability is being introduced. The proposed node stability based clustering algorithm (NSBCA) improves cluster stability, manageability and energy efficiency in MANET. The algorithm does not require to know the location of the node to be monitored by external means like GPS or mobility to be calculated by monitoring signal strength, the node itself monitor and records its movement and uses this information to elect cluster-head.

A weighted approach for MPR selection in OLSR protocol

Next generation of mobile communications will include combination of both infrastructure based network and infrastructure less. These types of networks are termed as hybrid wireless networks. Hybrid wireless network have emerged as a promising solution for bandwidth intensive services. These networks offer the advantage of spectrum reusability due to multi-hop relaying. However routing is a major issue of concern in these networks. OLSR is one of the popular proactive routing protocols In OLSR; MPR selection process involves huge overhead. The work mainly focuses on improving the efficiency of present OLSR routing protocol using hybrid wireless network. Also, OLSR is enhanced by employing a new weight based selection technique for Multi point relay (MPR) nodes. The various simulation results show that the use of hybrid wireless network architecture helps in better selection of MPRs node for OLSR. It improves the efficiency of OLSR protocol which is visible from improved throughput, higher packet delivery ratio, reduced end to end delay and routing overheads.

A Survey on Miscellaneous Attacks and Countermeasures for RPL Routing Protocol in IoT

The Internet of things is a worldview, where everyday objects can be equipped with distinguishing, detecting, networking, systems administration, and handling capacities that will enable them to speak with each other and with different devices and services over the Internet to achieve some goals. At last, IoT devices will be ubiquitous and context-aware and will remain empower surrounding knowledge. Be that as it may, without solid security establishments, attacks and threats in the IoT will overweight any of its advantages. This overview paper examines how traditional methodologies addressed security issue in routing with respect to their limitations, threats to secure routing in IoT and techniques to enhance security in routing scenario as a future work.

Bubble Rap Incentive Scheme for Prevention of Node Selfishness in Delay-Tolerant Networks

Delay-tolerant network (DTN), as its name suggests, is a network architecture that can tolerate delays in message delivery. In such an environment where there is a high rate of error and very large delay, routing becomes a challenging task due to the extreme conditions. DTNs incorporate store carry-and-forward routing technique to transfer data from source to destination using a new protocol called Bundle Protocol. While implementing this technique, it is assumed that each node cooperates in data forwarding and forwards the message irrespective of its sender and destination. But sometimes nodes may deny data forwarding and accepting messages of other nodes in order to save its own resources such as bandwidth and buffer. Such behaviour is termed as selfish behaviour whereby node may drop packets of other nodes or prevent them from forwarding further in order to save its own resources. Detecting selfish behaviour of nodes in DTN environments is a critical task. In order to overcome the selfish behaviour, nodes may be motivated by providing incentives in form of credits or virtual money. This paper presents a technique to detect selfishness of a node on the basis of its message forwarding and dropping behaviour, and a novel credit-based scheme to motivate nodes to cooperate in message forwarding. The proposed scheme is applied over Bubble rap routing algorithm which is a popular social-based routing algorithm.

A fuzzy logic based buffer management scheme with traffic differentiation support for delay tolerant networks

Delay tolerant networks (DTNs) are an emerging class of wireless networks which enable data delivery even in the absence of end-to-end connectivity. Under these circumstances, message replication may be applied to increase the delivery ratio. The requirement of long term storage and message replication puts a burden on network resources such as buffer and bandwidth. Buffer management is an important issue which greatly affects the performance of routing protocols in DTNs. Two main issues in buffer management are drop decision when buffer overflow occurs and scheduling decision when a transmission opportunity arises. The objective of this paper is to propose an enhancement to the Custom Service Time Scheduling traffic differentiation scheme by integrating it with a fuzzy based buffer ranking mechanism based on three message properties, namely, number of replicas, message size and remaining time-to-live. It uses fuzzy logic to determine outgoing message order and to decide which messages should be discarded within each traffic class queue. Results of simulation study show that the proposed fuzzy logic-based traffic differentiation scheme achieves improved delivery performance over existing traffic differentiation scheme for DTNs.

Controlled Replication Based Bubble Rap Routing Algorithm in Delay Tolerant Network

Delay-tolerant or opportunistic networks (DTNs) [1, 2] are special types of networks which allow transmission of data where there may be no end to end connection between source and destination. DTNs may lack continuous network connectivity and there may be very large delay in message delivery because of sparse node density. Thus routing in DTNs is a very challenging task because it must handle very long delays, frequent network partitions and resultant inconsistent network topology. Social-based routing approaches have arouse great interest in the context of DTN, where different social characteristics of DTN nodes are used to make better routing decisions. A controlled replication based scheme has been used to improve the performance of Bubble Rap routing algorithm. The proposed algorithm has been tested in both heterogeneous and real world mobility scenarios.