Abstract

Electromagnetic theory is one of the core subjects in Electrical/Electronics and Communication Engineering. It involves many concepts that are abstract and difficult to visualize, hence learning or teaching it is a challenge. This paper presents a web based virtual laboratory for electromagnetic theory course taught at undergraduate level, which can be used as a didactic tool by teachers and as a self learning tool by students. A set of ten topics have been chosen which broadly cover the basics of electromagnetic theory. The laboratory helps the students to visualize and experiment with abstract concepts of electromagnetic theory. It also contains theory supporting the experiment to aid teaching-learning process. The laboratory contains evaluation sections to assess student's understanding before and after performing virtual experiment. Assessment of the virtual lab done by evaluating students and feedback about the laboratory collected from both teachers and students are presented.

Abstract

The Millenium Development goals emphasize the need for building" open, rule-based, predictable and non-discriminatory" e-governance systems. However, building such open systems remains a challenge: on the one hand, the systems are required to be open, whereas, on the other, there is the need to preserve and protect private and confidential information of potentially millions of users. This requires that e-governance systems carry clear specifications of how access to users' documents is managed throughout an e-governance application's workflow.

Abstract

Aspect Oriented Programming (AOP) advocates the notion of aspects to encapsulate crosscutting concerns. A concern is a behavior in a computer program and is said to be crosscutting if the module(s) that address the behavior are scattered and tangled with other modules of the system. In this paper, we investigate the possibility of using AOP for software testing and non-invasive debugging. We have identified some crosscutting concerns like access control, logging, performance, tracing, etc., and developed a framework based on java bytecode instrumentation technique to inject these crosscutting concerns into the compiled code. The framework is available as a service, i.e., the service takes the required code as input and produces the changed code as output that contains the appropriate aspects. Thus, it is argued that the framework can be the basis for implementing the notion of “Enabling testing as a Service”.

Abstract

Pedagogical literature is generally rich with references to digitally savvy students, operating at twitch speed. This creates pressure on instructors, pedagogies, educational technologies to primarily cater to these digital natives. This paper conducts a descriptive study of students of rural AP to see if indeed Indian tier 2-3 students are of this caliber and description. Should the digital natives model be used for rural Indian student profile as well? Findings from our survey based study reveal that of the (N=372) tier 2, 3 students only 50% own a PC, only 41% surf the web, and of those who surf, it is mostly consumption behavior with social intent. And finally, while the confidence in learning and skills is high, English comprehension skills is poor. We feel that this profile of students is in contrast to the computer savvy image being projected, and should inform emerging educational technology projects aimed for rural India.

Abstract

We revive an old but little explored idea about how to think about algorithms and problem solving. Algorithms are discrete dynamical systems, also called iterative systems. Pursuing this point of view pays rich dividends. Important concepts like state space, next-state function, termination, fixed points, invariants, traces etc., can be mapped from dynamical systems to elements of algorithm design. Many of these concepts can be visualised through plots that trace the dynamic behaviour of the algorithm

Abstract

Global optimization of MRF energy using graph cuts iswidely used in computer vision. As the images are gettinglarger, faster graph cuts are needed without sacrificing op-timality. Initializing or reparameterizing a graph using re-sults of a similar one has provided efficiency in the past. Inthis paper, we present a method to speedup graph cuts us-ing shrink-expand reparameterization. Our scheme mergesthe nodes of a given graph to shrink it. The resulting graphand its mincut are expanded and used to reparameterize theoriginal graph for faster convergence. Graph shrinking canbe done in different ways. We use a block-wise shrinkingsimilar to multiresolution processing of images in our Mul-tiresolution Cuts algorithm. We also develop a hybrid ap-proach that can mix nodes from different levels without af-fecting optimality. Our algorithm is particularly suited forprocessing large images. The processing time on the fulldetail graph reduces nearly by a factor of 4. The overallapplication time including all book-keeping is faster by afactor of 2 on various types of images

Abstract

Displays remain flat and passive amidst the many changes in their fundamental technologies. One natural step ahead is tocreate displays that merge seamlessly in shape and appearance with one’s natural surroundings. In this paper, we present a system todesign, render to, and build view-dependentmultiplanar displaysof arbitrary piecewise-planar shapes, built using polygonal facets.Our system provides high quality, interactive rendering of 3D environments to a head-tracked viewer on arbitrary multiplanar displays.We develop a novel rendering scheme that produces exact image and depth map at each facet, producing artifact-free images on andacross facet boundaries. The system scales to a large number of display facets by rendering all facets in a single pass of rasterization.This is achieved using a parallel, perframe, view-dependent binning and prewarping of scene triangles. The display is driven using oneor more targetquilt imagesinto which facet pixels are packed. Our method places no constraints on the scene or the display and allowsfor fully dynamic scenes to be rendered interactively at high resolutions. The steps of our system are implemented efficiently oncommodity GPUs. We present a few prototype displays to establish the scalability of our system on different display shapes, formfactors, and complexity: from a cube made out of LCD panels to spherical/cylindrical projected setups to arbitrary complex shapes insimulation. Performance of our system is demonstrated for both rendering quality and speed, for increasing scene and display facetsizes. A subjective user study is also presented to evaluate the user experience using a walk-around display compared to a flat panelfor a game-like setting.

Abstract

Matching patches of a source image with patches of itself ora target image is a first step for many operations. Finding the optimumnearest-neighbors of each patch using a global search of the image isexpensive. Optimality is often sacrificed for speed as a result. We presentthe Mixed-Resolution Patch-Matching (MRPM) algorithm that uses apyramid representation to perform fast global search. We compare mixed-resolution patches at coarser pyramid levels to alleviate the effects ofsmoothing. We store more matches at coarser resolutions to ensure widersearch ranges and better accuracy at finer levels. Our method achievesnear optimality in terms of average error compared to exhaustive search.Our approach is simple compared to complex trees or hash tables used byothers. This enables fast parallel implementations on the GPU, yieldingupto 70×speedup compared to other iterative approaches. Our approachis best suited when multiple, global matches are needed

Abstract

Large scale reconstructions of camera matrices and pointclouds have been created using structure from motion from communityphoto collections. Such a dataset is rich in information; it representsa sampling of the geometry and appearance of the underlying space.In this paper, we encode the visibility information between and amongpoints and cameras asvisibility probabilities. The conditional visibilityprobability of a set of points on a point (or a set of cameras on a camera)can rank points (or cameras) based on their mutual dependence. Wecombine the conditional probability with a distance measure to prioritizepoints for fast guided search for the image localization problem. Wedefine dual problem of feature triangulation as finding the 3D coordinatesof a given image feature point. We use conditional visibility probabilityto quickly identify a subset of cameras in which a feature is visible

Abstract

Graphics models are getting increasingly bulkier with de-tailed geometry, textures, normal maps, etc. There is a lotof interest to model and navigate through detailed models oflarge monuments. Many monuments of interest have bothrich detail and large spatial extent. Rendering them for navi-gation on a single workstation is practically impossible, evengiven the power of today’s CPUs and GPUs. Many modelsmay not fit the GPU memory, the CPU memory, or eventhe secondary storage of the CPU. Distributed renderingusing a cluster of workstations is the only way to navigatethrough such models. In this paper, we present a design ofa distributed rendering system intended for massive mod-els. Our design has a server that holds the skeleton of thewhole model, namely, its scenegraph with actual geometryreplaced by bounding boxes at all levels. The server dividesthe screen space among a number of clients and sends thema list of objects they need to render using a frustum cullingstep. The clients use 2 GPUs with one devoted to visibilityculling and the other to rendering. Frustum culling at theserver, visibility culling on one GPU, and rendering on thesecond GPU form the stages of our distributed renderingpipeline. We describe the design and implementation of oursystem and demonstrate the results of rendering relativelylarge models using different clusters of clients in this paper