Computer Science and Engineering

Smart environments that can adapt based on the current context are extremely useful for automating even simple, mundane tasks. The key components of such an environment are sources that can extract the raw context, a synthesizer that can draw inferences by aggregating the context from different sources, and a set of policies that drive the adaptation. In this paper, we describe a context-based adaptation system to alleviate the distraction caused by one of the most ubiquitous devices of modern day -the mobile phone. Our system makes use of sources, such as RFID devices, that employ near-field communication technology to extract raw context. We describe how we adapt the roles of these devices to extract both environmental and personal context. To reduce the distraction caused by mobile phones, we have developed a policy-based mechanism to enable context-based adaptation of these devices. We have implemented a prototype of our system and conducted some usage studies. We describe the details of our implementation and present the lessons learned from the usability experiments.

Peer-to-Peer (P2P) network allow peer to distribute and obtain a file to be shared cooperatively. The successful growth of P2P network and its application is plagued by two important problems like Free Rider and Tragedy of commons, i.e. some selfish peers only download files without sharing its resources. This paper investigates the Free Rider and Tragedy of Common problem and encourages a peer to participate by proposing a trust agent based incentive mechanism. After applying this system theoretically, it improves the performance of the P2P system. Result obtained shows significant improvement which concludes that the proposed incentive mechanism will reduce the impact of Free Rider problem and effectively achieve fair sharing in P2P system.

— The modular exponentiation is an important operation for cryptographic transformations in public key cryptosystems like the Rivest, Shamir and Adleman, the Difie and Hellman and the ElGamal schemes. computing n a x mod and n b a y x mod for very large x,y and n are fundamental to the efficiency of almost all pubic key cryptosystems and digital signature schemes. To achieve high level of security, the word length in the modular exponentiations should be significantly large. The performance of public key cryptography is primarily determined by the implementation efficiency of the modular multiplication and exponentiation. As the words are usually large, and in order to optimize the time taken by these operations, it is essential to minimize the number of modular multiplications. In this paper we are presenting efficient algorithms for computing n a x mod and n b a y x mod. In this work we propose four algorithms to evaluate modular exponentiation. Bit forwarding (BFW) algorithms to compute n a x mod , and to compute n b a y x mod two algorithms namely Substitute and reward (SRW), Store and forward(SFW) are proposed. All the proposed algorithms are efficient in terms of time and at the same time demands only minimal additional space to store the pre-computed values. These algorithms are suitable for devices with low computational power and limited storage.

The world is moving towards a new realm of computing such as Internet of Things. The Internet of Things, however, envisions connecting almost all objects within the world to the Internet by recognizing them as smart objects. In doing so, the existing networks which include wired, wireless, and ad hoc networks should be utilized. Moreover, apart from other networks, the ad hoc network is full of security challenges. For instance, the MANET (mobile ad hoc network) is susceptible to various attacks in which the black hole attacks and its versions do serious damage to the entire MANET infrastructure. The severity of this attack increases, when the compromised MANET nodes work in cooperation with each other to make a cooperative black hole attack. Therefore this paper proposes an alleviation procedure which consists of timely mandate procedure, hole detection algorithm, and sensitive guard procedure to detect the maliciously behaving nodes. It has been observed that the proposed procedur...

The 1990s have seen a rapid growth of research interests in mobile ad hoc networking. The infrastructureless and the dynamic nature of these networks demands new set of networking strategies to be implemented in order to provide efficient end-to-end communication. This, along with the diverse application of these networks in many different scenarios such as battlefield and disaster recovery, have seen MANETs being researched by many different organisations and institutes. MANETs employ the traditional TCP/IP structure to provide end-to-end communication between nodes. However, due to their mobility and the limited resource in wireless networks, each layer in the TCP/IP model require redefinition or modifications to function efficiently in MANETs. One interesting research area in MANET is routing. Routing in the MANETs is a challenging task and has received a tremendous amount of attention from researches. This has led to development of many different routing protocols for MANETs, and each author of each proposed protocol argues that the strategy proposed provides an improvement over a number of different strategies considered in the literature for a given network scenario. Therefore, it is quite difficult to determine which protocols may perform best under a number of different network scenarios, such as increasing node density and traffic. In this paper, we provide an overview of a wide range of routing protocols proposed in the literature. We also provide a performance comparison of all routing protocols and suggest which protocols may perform best in large networks.

In Wireless sensor networks, sensor nodes sense the data from environment according to its functionality and forwards to its base station. This process is called Data collection and it is done either direct or multi-hop routing. In direct routing, every sensor node directly transfers its sensed data to base station which influences the energy consumption from sensor node due to the far distance between the sensor node and base station. In multi-hop routing, the sensed data is relayed through multiple nodes to the base station, it uses less energy. This paper introduces a new mechanism for data collection and routing based on River Formation Dynamics. The proposed algorithm is termed as RFDMRP: River Formation Dynamics based Multi-hop Routing Protocol. This algorithm is explained and implemented using MATLAB. The performance results are compared with LEACH and MODLEACH. The comparison reveals that the proposed algorithm performs better than LEACH and MODLEACH.

Advanced internet technologies providing services like e-mail, social networking, online banking, online shopping etc., have made day-today activities simple and convenient. Increasing dependency on the internet, convenience, and decreasing cost of electronic devices have resulted in frequent use of online services. However, increased indulgence over the internet has also accelerated the pace of digital crimes. The increase in number and complexity of digital crimes has caught the attention of forensic investigators. The Digital Investigators are faced with the challenge of gathering accurate digital evidence from as many sources as possible. In this paper, an attempt was made to recover digital evidence from a system's RAM in the form of information about the most recent browsing session of the user. Four different applications were chosen and the experiment was conducted across two browsers. It was found that crucial information about the target user such as, user name, passwords, etc., was recoverable.

There has been a surge towards physical memory forensics with recent development of valuable tools and techniques in acquisition and analysis. However, most of the research is skewed towards the Operating System architecture with primary focus on processes, threads, kernel modules etc. There has been little research towards retrieval of application level data. Moreover, the research is majorly application specific and keyword search oriented, involving text string search tools which use match and/or indexing algorithms to search digital evidence. Our paper aims to unearth application level data through a generic approach and provide some degree of automation to reduce the string search dependency. The paper revolves around the web browser and the HTTP protocol which are the basic elements of the interface between a user and the internet. Programs have been developed for the extraction of HTTP message headers from the acquired RAM image and a detailed analysis of how the information in these headers is crucial, follows.

Advanced internet technologies providing services like e-mail, social networking, online banking, online shopping etc., have made day-today activities simple and convenient. Increasing dependency on the internet, convenience, and decreasing cost of electronic devices have resulted in frequent use of online services. However, increased indulgence in the internet by people has also accelerated the pace of digital crimes. The increase in number and complexity of digital crime cases has caught the attention of forensic investigators. The Digital Investigators are faced with the challenge of gathering accurate digital evidence from as many sources as possible. In this paper, an attempt was made to recover digital evidence from a system's RAM in the form of information about the most recent browsing session of the user. Four different applications were chosen for the experiment and it was found that crucial information about the target user such as, user name, passwords, etc., was recoverable.

We report the design and implementation of a call-graph profiler for GNU Octave, a numerical computing platform. GNU Octave simplifies matrix computation for use in modeling or simulation. Our work provides a call-graph profiler, which is an improvement on the flat profiler. We elaborate design constraints of building a profiler for numerical computation, and benchmark the profiler by comparing it to the rudimentary timer start-stop (tic-toc) measurements, for a similar set of programs. The profiler code provides clean interfaces to internals of GNU Octave, for other (newer) profiling tools on GNU Octave.

In recent years, researchers have focused on many challenging aspects in the area of Wireless Sensor networks (WSNs). Development of energy efficient data collection protocols became the major concern in WSN. Clustering is one of the suitable techniques for energy efficiency. However, in clustering, the cluster are formed with uneven size. This unbalances the energy consumption among clusters which in turn reduce the lifetime of the network. In this paper, in order to balance the energy among clusters, a multi-hop concept is introduced for both intra and inter cluster communication. Firstly, the RFDMRP: River Formation Dynamics based Multi-hop Routing Protocol has been proposed. Later, this protocol is integrated with clustering and a new hybrid technique, named as hybrid clustering communication algorithm using RFDMRP (HCCRFD) is introduced. HCCRFD improves energy conservation by reducing overall packet transmission distance of intra and inter cluster communication, which results in increased network lifetime. Energy consumption of proposed algorithm has been analyzed mathematically. Also, the algorithms were simulated using MATLAB and outputs observed. The observed outputs were compared with existing protocols such as LEACH, DEEC, ERA, and ACH 2 in three different scenarios namely homogenous, heterogeneous environment, and node density. The comparison reveals that the proposed algorithm perform better than the existing protocols with respect to energy conservation and network lifetime.

Wireless Sensor Networks (WSNs) are class of networks composed of sensor nodes having sensing, communication, and computing capabilities which can monitor various environmental conditions like temperature, pressure, speed, gas, proximity, light, etc. Many applications such as smart transport systems, habitat monitoring, under water monitoring require WSNs to be mobile rather than static. Hence, Mobile Wireless Sensor Networks (MWSN) have become more prospective in human life applications. There exist various methods to organize large number of sensing devices to monitor, gather, aggregate data, and to find the best path to forward the data (routing) to the central node called Base Station. Cluster based routing is one of the efficient methods for data collection and aggregation. Non-centralized approaches for path selection and data forwarding eliminates single point failure and ensures accurate routing decisions. So, distributed cluster based routing prolongs network lifetime, improves Packet Delivery Ratio, and supports scalability in MWSN. A review on MWSN, its applications, issues in mobility management, existing cluster based distributed routing protocols, their features, parameters used for simulation, and limitations are presented in this paper.

Digital documents play a major role in modern era. They are easy to generate, modify and manage. The easy modifiable property of digital document makes it more vulnerable to forgery. It can be easily tampered or forged. So the challenge is to produce digital documents that are highly resistant to forgery and reliably confirms the real owner of the document. This can be resolved by biometric watermarking which make a direct relation between the document and its owner. A new biometric watermarking technique with secret key is proposed to digitize the authoritative documents issued by government / other organizations as a part of UID / Aadhar card project of India using biometric watermarking. Biometric code is generated from the biometric data collected from the owner of the document. The biometric code is watermarked in the document with a secret key to generate a biometric watermarked document that authenticates the real owner. De- watermarking the document with the same key yields ...

In Wireless sensor networks, sensor nodes sense the data from environment according to its functionality and forwards to its base station. This process is called Data collection. The Data collection process is done either directly or by multi-hop routing. In direct routing, every sensor node directly transfers its sensed data to base station which has an impact on energy consumption from sensor node due to the far distance between the sensor node and base station. In multi-hop routing, the sensed data is relayed through multiple nodes to the base station, it consumes less energy. This paper presents and analyzes the performance of a data collection routing protocol called RFDMRP: River Formation Dynamics based multi-hop routing protocol. The performance of RFDMRP is tested and analyzed for network parameters such as Network lifetime, Energy usage, and Node density & data aggregation impact on network lifetime. The simulated results are compared with two algorithms LEACH and MOD_LEAC...