Abstract

Optimal initiation of quantum dynamics of N-H photodissociation of pyrrole on the S0- 1πσ∗( 1A2) coupled electronic states by UV-laser pulses in an effort to guide the subsequent dynamics to dissociation limits is studied theoretically. Specifically, the task of designing optimal laser pulses that act on initial vibrational states of the system for an effective UV-photodissociation is considered by employing optimal control theory. The associated control mechanism(s) for the initial state dependent photodissociation dynamics of pyrrole in the presence of control pulses is examined and discussed in detail. The initial conditions determine implicitly the variation in the dissociation probabilities for the two channels, upon interaction with the field. The optimal pulse corresponds to the objective fixed as maximization of overall reactive flux subject to constraints of reasonable fluence and quantum dynamics. The simple optimal pulses obtained by the use of genetic algorithm based optimization are worth an experimental implementation given the experimental relevance of πσ∗-photochemistry in recent times.

Abstract

There are numerous situations when a service requester wishes to expertsourcea series of identical but non-trivial tasks from a pool of experts so as to achieve an assured accuracy level for each task, in a cost optimal way. The experts available are typically heterogeneous with unknown but fixed qualities and different service costs. The service costs are usually private to the experts and the experts could be strategic about their costs. The problem is to select for each task an optimal subset of experts so that the outcome obtained after aggregating the opinions from the selected experts guarantees a target level of accuracy. The problem is a challenging one even in a non-strategic setting since the accuracy of an aggregated outcome depends on unknown qualities. We develop a novel multi-armed bandit (MAB) mechanism for solving this problem. First, we propose a framework, Assured Accuracy Bandit (AAB)framework, which leads to a MAB algorithm, Constrained Confidence Bound for Non-Strategic Setting (CCB-NS). We derive an upper bound on the number of time steps this algorithm chooses a sub-optimal set, which depends on the target accuracy and true qualities. A more challenging situation arises when the requester not only has to learn the qualities of the experts but has to elicit their true service costs as well. We modify the CCB-NS algorithm to obtain an adaptive exploration separated algorithm Constrained Confidence Bound for Strategic Setting (CCB-S). The CCB-S algorithm produces an ex-post monotone allocation rule that can then be transformed into an ex-post incentive compatible and ex-post individually rational mechanism. This mechanism learns the qualities of the experts and guarantees a given target accuracy level in a cost optimal way. We also provide a lower bound on the number of times any algorithm must select a sub-optimal set and we see that the lower bound matches our upper bound up to a constant factor. We provide insights on a practical implementation of this framework through an illustrative example and demonstrate the efficacy of our algorithms through simulations

Abstract

The Cooperative Target Observation (CTO) problem has been of great interest in the multi-agents and robotics literature due to the problem being at the core of a number of applications including surveillance. In CTO problem, the observer agents attempt to maximize the collective time during which each moving target is being observed by at least one observer in the area of interest. However, most of the prior works for the CTO problem consider the targets movement to be Randomized. Given our focus on surveillance domain, we modify this assumption to make the targets strategic and present two target strategies namely Straight-line strategy and Controlled Randomization strategy. We then modify the observer strategy proposed in the literature based on the K-means algorithm to introduce five variants and provide experimental validation. In surveillance domain, it is often reasonable to assume that the observers may themselves be a subject of observation for a variety of purposes by unknown adversaries whose model may not be known. Randomizing the observers actions can help to make their target observation strategy less predictable. As the fifth variant, we therefore introduce Adjustable Randomization into the best performing observer strategy where the observer can adjust the expected loss in reward due to randomization depending on the situation.

Abstract

The popularity of digital currencies, especially cryptocurrencies, has been continuously growing since the appearance of Bitcoin. Bitcoin’s security lies in a proof-of-work scheme, which requires high computational resources at the miners. Despite advances in mobile technology, existing cryptocurrencies cannot be maintained by mobile devices due to their low processing capabilities. Mobile devices can only accommodate mobile applications (wallets) that allow users to exchange credits of cryptocurrencies. In this work, we propose LocalCoin, an alternative cryptocurrency that requires minimal computational resources, produces low data traffic and works with off-the-shelf mobile devices. LocalCoin replaces the computational hardness that is at the root of Bitcoin’s security with the social hardness of ensuring that all witnesses to a transaction are colluders. Localcoin features (i) a lightweight proof-of-work scheme and (ii) a distributed blockchain. We analyze LocalCoin for double spending for passive and active attacks and prove that under the assumption of sufficient number of users and properly selected tuning parameters the probability of double spending is close to zero. Extensive simulations on real mobility traces, realistic urban settings, and random geometric graphs show that the probability of success of one transaction converges to 1 and the probability of the success of a double spending attempt converges to 0.

Abstract

High-speed serial communication protocols are widely used in modern communication systems. High-speed serial protocols enable bandwidth scalability and system cost reduction. Full duplex serial communication involves a bi-directional data transfer from the link partners. A simplex communication channel enables one-way data transmission from one link partner to the other. Simplex channels are used in systems where uni-directional data transfer is required, for example a display device. Simplex channels further reduce the overall system cost. Initializing the simplex communication channel is challenging because of the lack of a back channel to communicate the link status from the receiver to the transmitter. Most of the protocols include a simplex sideband channel to communicate the link status. A sideband channel adds to the overall system cost. In this paper, the authors have discussed about a novel initialization methodology to initialize the high-speed simplex communication link to achieve 2x saving in logic area and 1.5x increase in latency.

Abstract

An All Programmable System-on-Chip (SoC) solution consisting of a hardened processor and a programmable fabric solution has been identified as a growing heterogeneous programmable platform catering to variety of application areas including communication, remote radio head, and software-defined radio and so on. The process to boot such a SoC with embedded processor and programmable fabric has been a challenge considering the complexity involved in multiple stages of booting. The boot sequence typically involves loading of first stage loader, configuring the programmable fabric with configuration bitstream followed by loading of user boot loader. Booting with typical boot devices like Quad Serial Peripheral Interface (QSPI), NAND or NOR flash results in increased boot time. The embedded PCI Express block in such SoC can be used as a carrier for the boot image including the user boot loader and the bitstream. The boot loader can be transferred from a remote host PC to the SoC's on chip memory over PCle link. Such boot process imparts significant improvement in boot time and ensures boot image security since the boot images can be stored in a secure processing system. Using boot over PCIe methodology, the authors have experimentally found 20x improvement in boot time over the state-of-the-art boot mechanisms.

Abstract

Development of ultra-wide band(UWB) technology is a major area in the present day technological developments in the radars and allied applications. They have a special application in the field of Intentional Electromagnetic Interference(IEMI). High Power Electromagnetic (HPEM) technology was developed particularly to achieve this IEMI. Generation and radiation are two major sub-technologies that fulfill the requirement of HPEM. This paper deals with the development of efficient and simple radiating elements to accomplish this requirement. The facts are experimentally proved for the two well-known structures, bi-cone and dipole, with a voltage of 50kV in the air dielectric medium. The measurement methodology is also discussed in brief. Dipole would be a first option to be adopted for this type of applications due to its simple structure and easily accommodate itself in the system.

Abstract

In this paper, RF resonant sensor is designed for measurement of complex permittivity of unknown sample. It takes advantage of peano curve fractal geometry (i.e. higher capacitance in minimum area). It operates in the ISM (industrial, scientific and medical) frequency band of 4-5 GHz. An empirical model of sensor is developed for the accurate calculation of complex permittivity of an unknown sample in terms of shifts in the resonant frequencies and reflection coefficients (S11) under loaded condition. Due to homogeneous E-field at fractal capacitor, placement position of sample will not affect the sensitivity. Significant frequency shifts as high as 60 M Hz, 80 M Hz, 116 M Hz and 134 M Hz are observed for relative permittivity of 5.4, 6.5, 8.9 and 10.6 respectively.

Abstract

A switching converter (dc-dc) cascaded with parallel low-dropout (LDO) regulators gives the best tradeoff in terms of high system efficiency and low output ripple for automotive power management ICs (PMICs). The minimum dc-dc output voltage is dependent on the highest LDO output and its corresponding dropout voltage. An adaptive LDO dropout technique based on maximum load current selector circuit has been proposed to improve the moderate and light load system efficiency of the hybrid PMIC with dc-dc supplying three independent LDO regulators. The circuit has been fabricated in AMS 0.35-μm high-voltage CMOS process and tested across wide supply voltage of 6-18 V, wide temperature range of -40 °C to 150 °C, and maximum load of 450 mA to meet the harsh automotive application requirements. The adaptive dropout circuit has minimal overhead (<;2%) in terms of area compared to fixed dropout architectures and negligible current consumption overhead. The overall system efficiency improvement of about 3%-10% is achieved with adaptive dropout scheme as per the experimental results. The concept is independent of dc-dc and LDO architecture and can be extended to many system-on-a-chip-based power supplies with dc-dc and LDO combination.

Abstract

wo-view stereo problem is a well researchedproblem in 3D computer vision. Algorithms proposedin the past have focussed on rectified stereo imageswhere the epipolar lines are parallel to the horizon-tal axis.The general problem of computing stereocorrespondences for unrectified images without anyknowledge of calibration parameters is an importantproblem but unexplored as yet. Our idea in this paperis to predict depth maps from two unrectified stereoimages using a modified Flownet architecture. Since,datasets for depth map reconstruction for unrectifiedstereo images for deep learning do not exist, we havecreated a dataset of turn table sequences of 3D modelsfrom Google 3D warehouse. Following the conceptsof Attention modelling, we implement an architecturefor combining correlations computed at multipleresolutions using a simple element-wise multiplicationof the correlations to aid the architecture to resolvecorrespondences for textureless and repeated texturedsurfaces. Our experiments show both qualitaitve andquantitative improvements of depth maps over theoriginal Flownet architecture.