Bidyut Gupta

A self-organizing map and its modeling for discovering malignant network traffic

Model-based intrusion detection and knowledge discovery are combined to cluster and classify P2P botnet traffic and other malignant network activity by using a Self-Organizing Map (SOM) self-trained on denied Internet firewall log entries. The SOM analyzed new firewall log entries in a case study to classify similar network activity, and discovered previously unknown local P2P bot traffic and other security issues.

A low-overhead non-block checkpointing algorithm for mobile computing environment

In this paper, we have proposed a new approach toward designing a low-overhead non-blocking single phase synchronous checkpointing algorithm suitable for distributed mobile computing environment. The algorithm produces a reduced number of checkpoints. To achieve this reduction in the number of the checkpoints we have used very simple data structure. Each process independently takes its decision whether to take a checkpoint or not. It makes the algorithm simple, fast, and efficient. The algorithm has been shown to be suitable for distributed mobile computing environment.

A generic mobile agent framework for ambient intelligence

The purpose of this paper is to introduce an innovative framework for implementation of ambient intelligence (AmI) environments. Compared to the existing state-of-the-art approaches, this framework creates a more decentralized and distributed AmI environment. In addition, the proposed approach is not limited to one specific domain, unlike many others. The openness of the presented architecture allows it to support a variety of devices ranged from small-embedded sensors to complex computing facilities. Finally, given that this approach is formulated based on multi-agent standard concepts, it can be easily implemented as add-on for existing software agent platforms to achieve rapid deployment. Implications for the development of this framework and future directions are discussed.

A Multi-Agent Based Approach for Particle Swarm Optimization

We propose a new approach towards particle swarm optimization named agent-based PSO. The swarm is elevated to the status of a multi-agent system by giving the particles more autonomy, an asynchronous execution, and superior learning capabilities. The problem space is modeled as an environment which forms clusters of points that are known to be non-optimal and this transforms the environment into a more dynamic and informative resource

A Reasoning Methodology for CW-Based Question Answering Systems

Question Answering Systems or (QA systems for short) are regarded as the next generation of the current search engines. Instead of returning a list of relevant documents, QA systems find the direct answer to the query posed in natural language. The key difficulty in designing such systems is to perform reasoning on natural language knowledgebase. The theory of Computing with Words (CW), proposed by Zadeh, offers a mathematical tool to formally represent and reason with perceptive information. CW views a proposition in natural language as imposing a soft/hard constraint on an attribute and represents it in form of a generalized constraint . In this paper we develop a reasoning methodology for the restricted domain CW-based QA systems. This methodology takes, as input, the knowledgebase and the query in form of generalized constraints and organizes the knowledge related to the query in a new tree structure, referred to as a constraint propagation tree . The constraint propagation tree generates a plan to find the most relevant answer to the query and allows improving the answer by establishing an information-seeking dialog with user.

Domino-effect free crash recovery for concurrent failures in cluster federation

In this paper, we have addressed the complex problem of recovery for concurrent failures in cluster computing environment. We have proposed a new approach in which we have dealt with both inter cluster orphan and lost messages unlike the existing works. The proposed recovery approach is free from the domino-effect and hence guarantees the least amount of recomputation after recovery. Besides, a process needs to save only its recent local checkpoint, which is also the case for a cluster. So number of trips to stable storage per process is always one during recovery. The proposed common check pointing interval is such that it enables a process to log the minimum number of messages it has sent. These features make our approach superior to the existing works.

Novel low-overhead roll-forward recovery scheme for distributed systems

An efficient roll-forward checkpointing/recovery scheme for distributed systems has been presented. This work is an improvement of our earlier work. The use of the concept of forced checkpoints helps to design a single phase non-blocking algorithm to find consistent global checkpoints. It offers the main advantages of both the synchronous and the asynchronous approaches, that is simple recovery and simple way to create checkpoints. The algorithm produces reduced number of checkpoints. Since each process independently takes its decision whether to take a forced checkpoint or not, it makes the algorithm simple, fast and efficient. The proposed work offers better performance than some noted existing works. Besides, the advantages stated above also ensure that the algorithm can work efficiently in mobile computing environment.

Second-Level Algorithms, Superrecursivity, and Recovery Problem in Distributed Systems

In this paper, we analyze network recovery algorithms, which allow computer networks to properly function in spite of failures. In this analysis, we use methods and tools of the theory of super-recursive algorithms. The concept of algorithm of the second level is introduced and studied. It is demonstrated that although the main components of various check-point/recovery algorithms are recursive algorithms, check-point/recovery algorithms, as a whole, are super-recursive second-level algorithms. Treating network recovery algorithms as second level algorithms is oriented at developing more powerful algorithms by combining existing ones in a common schema.

A new fault tolerant distributed mutual exclusion algorithm

In this paper we present a new fault-tolerant ditributed mutual exclusion algorithm for a computer network. A distributed computing system or a computer network consists of an interconnection of a set of N independently running computer systems called the nodea of the network, which communicate among themselves by exchanging messages only. We have shown that our algorithm functions properly when any of the cooperating nodes in the system fails. The communication delay may vary but haa an upper limit of A time units and the messages are not guaranteed to be received in the same order they are sent. The algorithm can tolerate an arbitrary number of node failurea and the message complexity of the algorithm is relatively very low.

Hierarchical pruning to improve bandwidth utilization of RPF-based broadcasting

Some of the attractive features of using Reverse Path Forwarding (RPF) method for broadcasting include reasonably low amount of memory necessary for storing the data structures in a router required by the protocol and ease of its implementation as it does not look for shortest path delivery. However, it generates quite a large number of duplicate packets resulting in poor bandwidth utilization. In this paper we have introduced a novel hierarchical pruning mechanism to improve bandwidth utilization for broadcasting using the RPF method. Experimental results support our theoretical findings of achieving very high reduction in the number of the duplicate packets generated.