Defence Science Journal 

About: Defence Science Journal is an academic journal published by Defence Scientific Information and Documentation Centre. The journal publishes majorly in the area(s): Computer science & Propellant. It has an ISSN identifier of 0011-748X. It is also open access. Over the lifetime, 2451 publications have been published receiving 17439 citations.

Metal matrix Composites

Abstract: This paper reviews the world wide upsurge in metal matrix composite research and development activities with particular emphasis on cast metal-matrix particulate composites. Extensive applications of cast aluminium alloy MMCs in day-to-day use in transportation as well as durable good industries are expected to advance rapidly in the next decade. The potential for extensive application of cast composites is very large in India, especially in the areas of transportation, energy and electromechanical machinery; the extensive use of composites can lead to large savings in materials and energy, and in several instances, reduce environmental pollution. It is important that engineering education and short-term courses be organized to bring MMCs to the attention of students and engineering industry leaders. India already has excellent infrastructure for development of composites, and has a long track record of world class research in cast metal matrix particulate composites. It is now necessary to catalyze prototype and regular production of selected composite components, and get them used in different sectors, especially railways, cars, trucks, buses, scooters and other electromechanical machinery. This will require suitable policies backed up by funding to bring together the first rate talent in cast composites which already exists in India, to form viable development groups followed by setting up of production plants involving the process engineering capability already available within the country. On the longer term, cast composites should be developed for use in energy generation equipment, electronic packaging aerospace systems, and smart structures.

Pixel-level Image Fusion using Wavelets and Principal Component Analysis

Abstract: Image registration and fusion are of great importance in defence and civilian sectors, e.g. , recognising a ground/air force vehicle and medical imaging. Pixel-level image fusion using wavelets and principal13; component analysis has been implemented and demonstrated in PC MATLAB. Different performance metrics with and without reference image are implemented to evaluate the performance of image fusion algorithms. As expected, the simple averaging fusion algorithm shows degraded13; performance. The ringing tone presented in the fused image can be avoided using wavelets with shift invariant property. It has been concluded that image fusion using wavelets with higher level of decomposition showed better performance in some metrics and in other metrics, principal components analysis showed better performance.13;

Microencapsulation Technology and Applications

Abstract: Microencapsulation technology allows a compound to be encapsulated inside a tiny sphere known as microsphere/microcapsule, having an average diameter as small as 1 mm to several hundred micro meters. Many different active materials like drugs, enzymes, vitamins, pesticides, flavours and catalysts have been successfully encapsulated inside microballoons or microcapsules made from a variety of polymeric and non polymeric materials including poly(ethylene glycol)s, poly(methacrylate)s, poly(styrene)s, cellulose, poly(lactide)s, poly(lactide-co-glycolide)s, gelatin and acacia, etc. These microcapsules release their contents at appropriate time by using different release mechanisms, depending on the end use of encapsulated products. This technology has been used in several fields including pharmaceutical, agriculture, food, printing, cosmetic, textile and defence. In defence sector this technology has introduced the concept of self-healing composites as well as chemical decontaminating fabrics. This review paper highlights the major reasons behind microencapsulation, important techniques of microencapsulation and application of microencapsulated products in different areas of science and technology.Defence Science Journal, 2009, 59(1), pp.82-95, DOI:http://dx.doi.org/10.14429/dsj.59.1489

Image Fusion Technique using Multi-resolution Singular Value Decomposition

Abstract: A novel image fusion technique based on multi-resolution singular value decomposition (MSVD) has been presented and evaluated. The performance of this algorithm is compared with that of well known image fusion technique using wavelets. It is observed that image fusion by MSVD perform almost similar to that of wavelets. It is computationally very simple and it could be well suited for real time applications. Moreover, MSVD does not have a fixed set of basis vectors like FFT, DCT and wavelet etc. and its basis vectors depend on the data set.Defence Science Journal, 2011, 61(5), pp.479-484, DOI:http://dx.doi.org/10.14429/dsj.61.705

Second-Level Digital Divide: Differences in People's Online Skills

Abstract: Much of the existing literature on the digital divide – the differences between the haves and have nots regarding access to the Internet – limits its scope to a binary classification of technology use by only considering whether someone does or does not use the Internet. To remedy this shortcoming, in this paper I look at the differences in people’s online skills. In order to measure people’s online ability, I assigned search tasks to a random sample of Internet users from a suburban county. Findings suggest that people search for content in a myriad of ways and there is a large variance in whether people are able to find various types of content on the Web and how long they take to complete online tasks. Age is negatively associated with one’s level of Internet skill, experience with the technology is positively related to online skill, and differences in gender do little to explain the variance in people’s ability to find content online. * I would like to thank Paul DiMaggio for his insightful comments throughout this project, Stan Katz for his ongoing support, and Erica Field, Hank Farber and members of the 2001/2002 Princeton Sociology Dissertation Support Group for helpful discussions. I am also grateful to Edward Freeland, James Chu, Carolyn Mordas, Jeremy Davis-Turak, and Inna Barmash for their assistance with various components of the project. Generous support from the Markle Foundation is kindly acknowledged. The project has also been supported in part by NSF grant #SES9819907, a grant from the Russell Sage Foundation, and through a grant from the Pew Charitable Trusts to the Center for Arts and Cultural Policy Studies, Princeton University. I am also grateful to the Fellowship of Woodrow Wilson Scholars at Princeton University. ** Sociology Department, Wallace Hall, Princeton University, Princeton, NJ 08544. Tel: 1-609258-6915; Fax: 1-609-258-2180; Email: papers-at-eszter-dot-com Eszter Hargittai -First Monday -Second-Level Digital Divide :: 2 Introduction: Inequalities in Internet Use Much of the literature documenting the Internet’s spread across the population has focused on the differences among those who have access to the Internet and those who do not, or the differences among those who use it and those who do not. Since the National Telecommunications Information Administration published its first report “Falling Through the Net: A Survey of the Have Nots in Rural and Urban America” in 1995, many analyses have been written on the inequalities of access to and use of the medium. Existing studies of differential Internet access and use document inequalities among various segments of the population (Bucy 2000) with particular attention to education (NTIA 2000) race (Hoffman 1999), gender (Bimber 2000), age (Loges and Jung 2001), income (Benton 1998) and rural residence (Strover 1999). These studies have been essential in understanding inequalities in access to the Internet, or what has come to be known as the “digital divide”. Here, I argue that as the medium spreads to a majority of the population (NTIA 2002) it is increasingly important to look at not only who uses the Internet, but also to distinguish among people’s varying levels of online skills. Skill, in this context, is defined as the ability to efficiently and effectively find information on the Web. By exploring the differences in how people use the Web for information retrieval, we can discern if there is a “second-level digital divide” in the making as the Web spreads to the majority of the American population. To explore this question, I report findings from a project that explores people’s ability to locate content online. Documenting differences in people’s Web use skills allows us to distinguish between how different kinds of people are able to take advantage of the medium in varying ways. Refining the current approach to the digital divide While most reports identify differences among various segments of the population, over time studies emphasize the increasing diffusion of the medium among the population at large (Howard, Rainie and Jones 2001; Katz and Rice 2002; NTIA 2000; 2002; Pew Internet and American Life Project 2000). As more people start using the Web for communication and information retrieval, it becomes less useful to merely look at binary classifications of who is online when discussing questions of inequality in relation to the Internet (DiMaggio and Hargittai 2001). Eszter Hargittai -First Monday -Second-Level Digital Divide :: 3 Rather, we need to start looking at differences in how those who are online use the medium, that is, differences in people’s online skills. It is important to consider more than mere access to the network when studying the differential spread of the Internet across the population and inequalities in people’s use of the medium. Given the increasing spread of the medium, it is important to expand the research agenda to allow analyses of the differences among Internet users. That is, how can we talk about the Internet’s effect on political participation if a user does not possess the skills to find political information? Similarly, how can the Internet prove to be a useful link between government and citizens if people are unable to find official documents online? Information about people’s online skills tells us to what extent they are able to use the medium in ways of most interest to them and in ways that are most useful to their particular needs. The ability to find different types of information online allows people to use the medium to their maximum benefit. If users often give up in frustration and confusion then merely having access does not mean that a digital divide has been solved because a divide remains in their capacity for effective use of the Internet. As Kiesler et al. (2000) note, the computer – currently the basis of most users’ Internet access in the United States – is still not an appliance with obvious directions when something does not seem to go as expected. By measuring users’ Internet skills, we can bridge the gap in the literature between mere structural measures of access and descriptions of what people do online to account for what different people are able to do online.