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Articles by S. Kannan
Total Records ( 17 ) for S. Kannan
  S. Kannan , M. Krishnan , S. Sundarraj , C. Meenambigai and M. Vimaladevi
 

Problem statement: It is widely accepted thought that the weak promoters control the RNA synthesis and play regulatory role in complex genetic networks in bacterial system. An experiment had been designed to address whether mutations in the -16/-17 region affect the rate of transcription at an activator-independent promoter in E. coli or not?
Approach:
The aim of this study was to determine whether mutations in the -16/-17 region affect the rate of expression at an activator-dependent promoter in JM109 strain of E. coli. Primers were constructed to amplify the mutant promoter genes through PCR. The amplified PCR product was checked and then inserted into the MCS region of pAA128 plasmid. Further the plasmid vector was transformed into JM109 strain of E. coli and then cloned the selected transformats. Finally, the plasmid from each mutant colony was then sequenced using the protocol supplied with the Amersham Pharmacia Biotech T7 sequencing Kit. The JM109 cultures for which the sequences were determined, then assayed for β-galactosidase activity to assess the rate of gene expression from the altered promoters.
Results:
The present investigation revealed that the extended-10 promoter region has a substantial effect on the rate of transcription at weak promoter sequence and also bearing little resemblance to the consensus sequence recognized by RNA. The expression of the genetically engineered plasmid proved that the 2 bps (-16 and -17 base pair) found adjacently upstream of the extended-10 promoter have an effect on the level of transcription. This was achieved by site specific base substitutions into the weak promoter of a modified lac operon lacking any activator or repressor binding sites. The results from gene expression assays of several mutants showed a distinct preference for either GG or TT located adjacently upstream of the extended promoter element. Thus the present study emphasized that extended promoter region also played a key role in regulation transcription initiation in JM109 strain of E. coli.
Conclusion:
The present study concluded that the site specific changed in the extended promoter regions, particularly the-17/-16 base pairs had greater influence in the transcription initiation in E. coli. Thus the promoter engineering study will definitely pave the way to do both, on or off the genetic switches in bacterial system according to our needs to produce high protein of interest or decrease or block the expression of a particular unwanted protein.

  S. Kannan , S. Karthik and V.P. Arunachalam
  Mobile Ad-hoc Networks (MANET) are self-organizing and self-configuring multihop wireless networks where the structure of the network changes dynamically. This is mainly due to the mobility of nodes. The nodes in the network not only acts as hosts but also as routers that route data to or from other nodes in network. In mobile ad-hoc networks, a routing procedure is always needed to find a path so as to forward the packets appropriately between the source and the destination. In a MANET, temporary link failures and route changes occur frequently. With the assumption that all packet losses are due to congestion, TCP performs poorly in such an environment. This study proposes a new mechanism called TASR, TCP-aware source routing which can improve TCP performance in wireless Ad-hoc networks. TASR adds a hold state to an existing routing protocol to reduce consecutive timeouts, retransmissions and out-of-ordered packets in TCP. In the simulation study, TASR achieves up to a 60% improvement in performance without requiring any TCP stacks in end systems to be modified.
  S. Kannan and V. Seenivasagam
  The application of biometric authentication has no limit and the dimension of biometric feature can be extended to any level. Based on the biometric features, there are many authentication mechanisms discussed earlier but suffer with the problem of authentication efficiency where there will be micro differences between one to many people. The biometric authentication system uses the micro difference and unique feature of any person to perform authentication and the efficiency of the system is depending on how accurate the system is most methods suffer with false authentication and poor verification accuracy and to solve those issues a multi view edge model has been discussed in this study. This study presents a multi view edge model which computes sectional similarity on each edge model where there will be unique noticeable difference between any two persons. The method converts the sectional features of the multi view edge model into the sectional similarity matrix and the method extracts the features of nose, eye and mouth into a signature matrix. Using multi feature signature resemblance technique, the method computes the similarity between different features of the data set. The proposed method improves the performance of biometric authentication and reduces the false positive ratio in biometric authentication.
  S. Kannan , T. Maragatham , S. Karthik and V.P. Arunachalam
  MANET has no clear line of defense so, it is accessible to both legitimate network users and malicious attackers. In the presence of malicious nodes, one of the main challenges in MANET is to design the robust security solution that can protect MANET from various routing attacks. Different mechanisms have been proposed using various cryptographic techniques to countermeasure the routing attacks against MANET. However, these mechanisms are not suitable for MANET resource constraints, i.e., limited bandwidth and battery power because they introduce heavy traffic load to exchange and verifying keys. In this study, the current security issues in MANET are investigated. Particularly, we have examined different routing attacks such as flooding, black hole, link spoofing attacks and some detection methods like profile-based detection, specification-based detection as well as existing solutions to protect MANET protocols.
  S. Kannan , S. Karthik and V.P. Arunachalam
  Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile hosts forming a temporary network without the aid of any stand-alone infrastructure or centralized administration. Mobile ad-hoc networks are self-organizing and self-configuring multihop wireless networks where the structure of the network changes dynamically. This is mainly due to the mobility of nodes. The nodes in the network not only acts as hosts but also as routers that route data to or from other nodes in network. In mobile ad-hoc networks a routing procedure is always needed to find a path so as to forward the packets appropriately between the source and the destination. The main aim of any ad-hoc network routing protocol is to meet the challenges of the dynamically changing topology and establish a correct and an efficient communication path between any two nodes with minimum routing overhead and bandwidth consumption. The design problem of such a routing protocol is not simple since, an ad-hoc environment introduces new challenges that are not present in fixed networks. A number of routing protocols have been proposed for this purpose like Ad-Hoc On Demand Distance Vector (AODV), Dynamic Source Routing (DSR), Destination-Sequenced Distance Vector (DSDV). In this research, we study and compare the performance of the following three routing protocols AODV, DSR and DSDV.
  S. Kannan , T. Kalaikumaran , S. Karthik and V.P. Arunachalam
  A mobile ad-hoc network is a self configuring network connected by wireless links. No infrastructure or central administration is needed for these type of networks. Therefore, they are suitable only for temporary communication links. An important issue in computer network is to design the network in such a way to cope up with the speed required today. The task of routing the packets from a source to the particular destination in ad-hoc networks is hard because the network elements are mobile and there is no central control over the network elements. In any network, the data packets have to be routed to the destination with minimum loss, minimum delay and maximum packet delivery ratio. Therefore, there must be an efficient routing algorithm which satisfies all these quality of service requirements and it must also be robust and adaptive. The algorithm Multi Agent Ant Based Routing Algorithm is designed from the ACO framework, inspired by the behavior of biological ants. The algorithm consists of both reactive and proactive components. This technique increases node connectivity and decreases average end to end delay and increase packet delivery ratio. Since node connectivity increases, packet loss is reduced. The simulations are carried out by NS-2 and the results prove that Multi Agent Ant Based Routing Algorithm outperforms AntHocNet, AODV and DSR in terms of average end to end delay and packet delivery ratio.
  S. Karthik , S. Kannan , V.P. Arunachalam , T. Ravichandran and M.L. Valarmathi
  Denial of Service (DoS) attacks constitutes one of the major threats and among the hardest security problems in today's Internet. Of particular concern are Distributed Denial of Service (DDoS) attacks whose impact can be proportionally severe. With little or no advance warning, a DDoS attack can easily exhaust the computing and communication resources of its victim within a short period of time. Because of the seriousness of the problem many defense mechanisms have been proposed to combat these attacks. This study aims to provide an understanding of the existing attack methods, tools and defense mechanisms, so that a better understanding of DDoS attacks can be achieved. The goal of the study is to simulate an environment by extending NS2, setting attacking topology and traffic which can be used to evaluate and compare the methods of DDoS attacks and tools. Based on the simulation and evaluation results, more efficient and effective algorithms, techniques and procedures to combat these attacks may be developed.
  S. Kannan , T. Kalaikumaran , S. Karthik and V.P. Arunachalam
  Understanding and using the internet in worldwide is a challenging problem that is typically addressed by analyzing network traces. However, obtaining such traces presents its own set of challenges owing to either privacy concerns or to other operational difficulties. The key hypothesis of the research here is that most of the information needed to profile, the internet endpoints is already available around us on the web. We implement and deploy a Google-based profiling tool which accurately characterizes endpoint behaviour by collecting and strategically combining information freely available on the web. Unconstrained endpoint profiling approach is used to profile and classify the endpoints. The websites are classified and clustered based on the search hits which contain the hit text and URL. On querying, it matches the domain name and URL if it does not match then it verifies the key words. The key words in the web cache are clustered using Fuzzy C-means algorithm which enhances the speed of the search engine.
  R. Raghul and S. Kannan
  In the context of wireless sensor networks, nodes have limited energy and forward messages of different importance. An algorithmic technique called Band-based Directional Broadcast is used to control the direction of broadcasts that originate from the sensor nodes. A key challenge is how to gather the sensor data in a manner that is energy efficient with respect to the sensor nodes that serve as sources of the sensor data. In the project, an optimal selective forwarding scheme is introduced in order to save energy in wireless sensor networks. The goal is to direct each broadcast of sensor data toward the mobile sink, thus reducing costly forwarding of sensor data packets. The technique is studied by simulations that consider energy consumption and data deliverability.
  S. Kannan , V.P. Arunachalam and S. Karthik
  Group communications are important in Mobile Ad hoc Networks (MANET). Multicast is an efficient method for implementing group communications. However, it is challenging to implement multicast packet forwarding over a dynamic topology. Researchers propose a novel Efficient Geographic Multicast Protocol (EGMP). A network wide zone based bi-directional tree is constructed to achieve more efficient multicast delivery. The position information is used to guide the zone structure building, multicast tree construction and multicast packet forwarding which efficiently reduces the overhead for route searching and tree structure maintenance. Several strategies have been proposed to further improve the efficiency of the protocol, for example introducing the concept of zone depth for building an optimal tree structure and integrating the location search of group members with the hierarchical group membership management. Finally, researchers design a scheme to handle empty zone problem faced by most routing protocols using a zone structure. The scalability and the efficiency of EGMP are evaluated through simulations. The simulation results demonstrate that EGMP has high packet delivery ratio and low control overhead and multicast group joining delay under all test scenarios and is scalable to both group size and network size. EGMP has significantly lower control overhead, data transmission overhead and multicast group joining delay.
  S. Kannan , Ishwarya , S. Karthik and V.P. Arunachalam
  In a mobile ad-hoc network, temporary link failures and route changes occur frequently. With the assumption that all packet losses are due to congestion, TCP performs poorly in such an environment. This study proposes a new mechanism called TASR, TCP-aware source routing which can improve TCP performance in wireless ad-hoc networks. TASR adds a hold state to an existing routing protocol to reduce consecutive timeouts, retransmissions and out-of-ordered packets in TCP. In the simulation study, TASR achieves up to a 60% improvement in performance without requiring any TCP stacks in end systems to be modified.
  S. Kannan , T. Kalaikumaran , S. Karthik and V.P. Arunachalam
  Routing problems in mobile ad-hoc networks have been receiving attention in the last few years. Most of the proposed routing protocols concentrate on finding and maintaining routes in the face of changing topology caused by mobility or other environmental changes. The power aware routing protocols and the topology control algorithms have been developed to address the issue of limited energy reserve of the nodes in ad-hoc networks. In this study, an algorithm has been designed and it has been enhanced with the AODV protocol for transmitting high density data over the ad-hoc network. This enhanced protocol is named as EL-AODV protocol. Enabling the high density data over, ad-hoc networks is more exigent as the links are highly error-prone and go down frequently. The challenge in data transmission over ad-hoc networks is due to the nomadic nature of the host and identifying a dynamic routing protocol that efficiently finds a stable route between mobile nodes. The simulation results show that the pro-posed scheme shows better performance when compared with existing protocol.
  S. Kannan , V.P. Arunachalam and S. Karthik
  In the context of wireless sensor networks, nodes have limited energy and forward messages of different importance. An algorithmic technique called band-based directional broadcast is used to control the direction of broadcasts that originate from the sensor nodes. A key challenge is how to gather the sensor data in a manner that is energy efficient with respect to the sensor nodes that serve as sources of the sensor data. In the research, an optimal selective forwarding scheme is introduced in order to save energy in wireless sensor networks. The goal is to direct each broadcast of sensor data toward the mobile sink, thus reducing costly forwarding of sensor data packets. The technique is studied by simulations that consider energy consumption and data deliverability.
  S. Kannan , T. Kalaikumaran , S. Karthik and V.P. Arunachalam
  MANET has no clear line of defense so, it is accessible to both legitimate network users and malicious attackers. In the presence of malicious nodes, one of the main challenges in MANET is to design the robust security solution that can protect MANET from various routing attacks. Different mechanisms have been proposed using various cryptographic techniques to countermeasure the routing attacks against MANET. However, these mechanisms are not suitable for MANET resource constraints, i.e., limited bandwidth and battery power because they introduce heavy traffic load to exchange and verifying keys. In this study, the current security issues in MANET are investigated. Particularly, the researchers have examined different routing attacks such as flooding, black hole, link spoofing attacks and some detection methods like profile-based detection specification-based detection as well as existing solutions to protect MANET protocols.
  S. Kannan , S. Karthik and V.P. Arunachalam
  Mobile Ad-hoc Networks (MANET) are self-organizing and self-configuring multihop wireless networks where the structure of the network changes dynamically. This is mainly due to the mobility of nodes. The nodes in the network not only acts as hosts but also as routers that route data to or from other nodes in network. In mobile ad-hoc networks a routing procedure is always needed to find a path so as to forward the packets appropriately between the source and the destination. The main aim of any ad-hoc network routing protocol is to meet the challenges of the dynamically changing topology and establish a correct and an efficient communication path between any two nodes with minimum routing overhead and bandwidth consumption. The design problem of such a routing protocol is not simple since an ad-hoc environment introduces new challenges that are not present in fixed networks. A number of routing protocols have been proposed for this purpose like Ad-Hoc On Demand Distance Vector (AODV), Dynamic Source Routing (DSR), Destination Sequenced Distance Vector (DSDV). In this study, we study and compare the performance of the following three routing protocols AODV, DSR and DSDV.
  S. Kannan , V.P. Arunachalam and S. Karthik
  This research investigates distributed clustering scheme and proposes an Ad hoc On demand Distance Vector (AODV) routing protocol for Delay-Tolerant Mobile Networks (DTMNs). The basic idea is to distributively group mobile nodes with similar mobility pattern into a cluster which can then interchangeably share their resources (such as buffer space) for overhead reduction and load balancing, aiming to achieve efficient and scalable routing in DTMN. An ad hoc network is self-organizing and adaptive. Networks are formed on the fly, devices can leave and join the network during its lifetime, devices can be mobile within the network, the network as a whole may be mobile and the network can be deformed on the fly. Devices in mobile ad hoc networks should be able to detect the presence of other devices and perform the necessary set-up to facilitate communications and the sharing of data and services. Due to the lack of continuous communications among mobile nodes and possible errors in the estimation of nodal contact probability, convergence and stability become major challenges in distributed clustering in DTMN. Extensive simulations are carried out to evaluate the end to end delay and overhead of the proposed Ad hoc On demand Distance Vector (AODV) routing protocol.
  S. Kannan
  Social support is an important, modifiable risk factor in a number of chronic illnesses including End-Stage Renal Disease (ESRD). Increased social support has possibility of positive affect outcomes through a number of mechanisms including decreased levels of depressive affect, increased patient perception of quality of life, increased access to health care, increased patient perception of quality of life and direct physiologic impacts on the immune system. Higher levels of social support have been linked to survival in several studies of patients with and without renal disease. It might be acquired from family, friends, coworkers, spiritual advisors, health care personnel or members of one’s own community or neighborhood. The study analyses extent of care provided by family, health teams, society and community and tries to find out the limitations and suggests remedies. The study also focuses various dimensions of social support for such patients. The responses collected from the patients who visited the Post Graduate Institute of Medical Education and Research, Chandigarh, for ESRD treatment during the period, January and February 2015 are selected for this study. There are about 140 cases reported, out of which 100 cases has been selected by using simple Random Sampling Method and collected information through structure interview schedule. The study results concluded that overall social support extended by the family members, health care teams, colleagues, friends and relatives towards ESRD patients is appreciable in the study area. However, in certain cases like respondents in the old age group, among females, illiterates, respondents hailing from rural area, unmarried having more children and low income group are not able to get full social support in the study area. While, conducting the awareness camps on end stage renal disease, this group of people should be concentrated more in the region.
 
 
 
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