Abstract

Detecting multiple planes in images is a challenging problem, but one with many applications. Recent work such as J-Linkage and Ordered Residual Kernels have focussed on developing a domain independent approach to detect multiple structures. These multiple structure detection methods are then used for estimating multiple homographies given feature matches between two images. Features participating in the multiple homographies detected, provide us the multiple scene planes. We show that these methods provide locally optimal results and fail to merge detected planar patches to the true scene planes. These methods use only residues obtained on applying homography of one plane to another as cue for merging. In this paper, we develop additional cues such as local consistency of planes, local normals, texture etc. to perform better classification and merging. We formulate the classification as an MRF problem and use TRWS message passing algorithm to solve non metric energy terms and complex sparse graph structure. We show results on challenging dataset common in robotics navigation scenarios where our method shows accuracy of more than 85 percent on average while being close or same as the actual number of scene planes.

Abstract

When multiple virtual machines (VMs) are co scheduled on the same physical machine, they may undergo a performance degradation. The performance degradation is due to the contention for shared resources like last level cache, hard disk, network bandwidth etc. This can lead to service-level agreement violations and thereby customer dissatisfaction. The classical approach to solve the co scheduling problem involves a central authority which decides a co schedule by solving a constrained optimization problem with an objective function such as average performance degradation. In this paper, we use the theory of stable matchings to provide an alternate game theoretic perspective to the co scheduling problem wherein each VM selfishly tries to minimize its performance degradation. We show that the co scheduling problem can be formulated as a Stable Roommates Problem (SRP). Since certain instances of the SRP do not have any stable matching, we reduce the problem to the Stable Marriages Problem (SMP) via an initial approximation. Gale and Shapley proved that any instance of the SMP has a stable matching and can be found in quadratic time. From a game theoretic perspective, the SMP can be thought of as a matching game which always has a Nash equilibrium. There are distributed algorithms for both the SRP and SMP problems. A VM agent in a distributed algorithm need not reveal its preference list to any other VM. This allows each VM to have a private cost function. A principal advantage of this problem formulation is that it opens up the possibility of applying the rich theory of matching markets from game theory to address various aspects of the VM co scheduling problem such as stability, coalitions and privacy both from a theoretical and practical standpoint. We also propose a new workload characterization technique for a combination of compute and memory intensive workloads. The proposed technique uses a sentinel program and it requires only two runs per workload for characterization. VMs can use this technique in deciding their partner preference ranks in the SRP and SMP problems. The characterization technique has also been used in proposing two new centralized VM co scheduling algorithms whose performance is close to the optimal Blossom algorithm.

Abstract

The compiler optimizations we enable and the order in which we apply them on a program have a substantial impact on the program execution time. Compilers provide default optimization sequences which can give good program speedup. As the default sequences have to optimize programs with different characteristics, they embed in them multiple subsequences which can optimize different classes of programs. These multiple subsequences may falsely interact with each other and affect the potential program speedup achievable. Instead of searching for a single universally optimal sequence, we can construct a small set of good sequences such that for every program class there exists a near-optimal optimization sequence in the good sequences set. If we can construct such a good sequences set which covers all the program classes in the program space, then we can choose the best sequence for a program by trying all the sequences in the good sequences set. This approach completely circumvents the need to solve the program classification problem. Using a sequence set size of around 10 we got an average speedup up to 14% on PolyBench programs and up to 12% on MiBench programs. Our approach is quite different from either the iterative compilation or machine-learning-based prediction modeling techniques proposed in the literature so far. We use different training and test datasets for cross-validation as against the Leave-One-Out cross-validation technique.

Abstract

In this paper, we present a noise cancellation technique for common gate ultra wide band (UWB) low noise amplifiers (LNAs) which not only reduces the noise but also increases the gain. On implementing this technique in one of the existing UWB LNAs significant reduction of noise figure (NF) compared to same LNA without noise cancellation technique was observed. Noise cancellation of the most dominating thermal noise source viz. the input matching device with theoretical analysis is presented in this paper. Simulation results with TSMC 0.18 (m CMOSRF technology shows a peak gain of 28 dB and base NF of 3.16 dB for a 6.6 GHz (2.4-9 GHz) band LNA with noise cancellation when compared to peak gain of 21 dB and base NF of 4.09 dB without noise cancellation. Both theoretical analysis and simulation results are in good agreement.

Abstract

In recent research works on magnetic thin films for RFIC Spiral Inductors it has been shown that patterning magnetic material improves the performance of inductors. In this paper it is presented that controlled formation of magnetic domains in patterned Permalloy thin films plays a vital role in boost of inductance and quality factor of spiral inductors.

Abstract

A novel CMOS current bleeding mixer based on inductive degeneration has been proposed in this paper. The noise figure of a radio frequency (RF) mixer is considerably affected by the flicker noise. This flicker noise can be tuned down by employing inductive degeneration at source and gate as the degenerative inductors improve the linearity and reduce the noise figure. A conventional current bleeding Gilbert mixer is also designed for analysis and comparison with proposed design. These mixers are designed using 0.18 micron technology. The simulated results show that the proposed mixer design has conversion gain of 12.47 dB, 1.7 dB decrease of noise figure and 3.72 dBm improvement of IIP3 at a maximum LO power of -3 dBm as compared to the conventional bleeding mixer.

Abstract

In this paper we discuss the effects of domain patterned magnetic shielding, using Permalloy, on Spiral Inductors employed in CMOS RFICs. Ferromagnetic Resonance of the domain patterned Permalloy is not observed in the measured frequency range of 1 GHz to 5.5 GHz and an improvement in Inductance and Quality factor of Spiral Inductor is noticed.

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”.