Efficient coding of information: Huffman coding

In his classic paper of 1948, Claude Shannon considered the problem of efficiently describing a source that outputs a sequence of symbols, each associated with a probability of occurrence, and provided the theoretical limits of achievable performance. In 1951, David Huffman presented a technique that attains this performance. This article is a brief overview of some of their result

Tree-Based Construction of LDPC Codes Having Good Pseudocodeword Weights

We present a tree-based construction of LDPC codes that have minimum pseudocodeword weight equal to or almost equal to the minimum distance, and perform well with iterative decoding. The construction involves enumerating a $d$-regular tree for a fixed number of layers and employing a connection algorithm based on permutations or mutually orthogonal Latin squares to close the tree. Methods are presented for degrees $d=p^s$ and $d = p^s+1$, for $p$ a prime. One class corresponds to the well-known finite-geometry and finite generalized quadrangle LDPC codes; the other codes presented are new. We also present some bounds on pseudocodeword weight for $p$-ary LDPC codes. Treating these codes as $p$-ary LDPC codes rather than binary LDPC codes improves their rates, minimum distances, and pseudocodeword weights, thereby giving a new importance to the finite geometry LDPC codes where $p > 2$.Comment: Submitted to Transactions on Information Theory. Submitted: Oct. 1, 2005; Revised: May 1, 2006, Nov. 25, 200

How Farmers Benefit from Integration of EO, Meteorological, Positioning and Field Data in an Analytics Engine – The AGRI-GIS Example of S Odisha, India

Today, space-based EO data, meteorological observations and positioning information, integrated with ground data and maps, plays an important role in bringing logical decision-making, intelligence and wisdom in society - even at grass-root level. World over, society is generating, referencing, archiving and using vast amount of time-stamped geographically referenced data sets – enabling the development of integrated solutions that benefits individual citizens, societies, nations and humanity, in general. Because of this large amounts of spatial data availability the science of Spatial Analytics is becoming highly prevalent and relevant.   The Centre for Spatial Analytics and Advanced GIS (C-SAG; www.csag.res.in) is developing an Agri-GIS - a suite of Spatial Analytics solutions based on EO images, meteorological data, Positioning data, various maps and different field data sets. The focus of the Agri-GIS is to address Smallholder Farmers – farm level aggregation and dis-aggregation of crop and socio-economic parameters; assess crop suitability of beneficiary land; assess crop-water model; help farmers on nutrition management; provide information on available production technologies, financing options, insurance options, access to inputs and market access etc. The strength of the C-SAG Agri-GIS model stems on a “single, common, standardized, integrated robust and reliable” multi-layered (about 304 parameters), spatially referenced and geo-tagged database – modelling for individual farmer's social, economic and natural resources queries. Out of the 304 parameters, space based inputs provide the critical 25% - mainly from near real-time EO images of various resolutions/receptivity and meteorological data. Another 20-30% of field observations are based on space-based Positioning - the rest are geo-tagged tables and records. Agri-GIS is developed in 613 villages of S Odisha in India and covers almost 80,000 farmers.   This Agri-GIS is an end-to-end solution that combines ground-, space-based EO/meteorological/positioning data into a GIS model to address specific farmer requirements at bettering his crop production and yield and also his economic condition by increased income. The paper will address how assessment of farmer’s needs of information in the various farming communities in Odisha state was taken up, the chain of Spatial Analytics and the final deliverables of 5 Farmer Advisories in each crop season. The paper will also highlight the partnerships of C-SAG, Tata Trusts and the farming communities and how a good working relationships between various stakeholders have been developed for the projec

Microstructural and Compositional Characterisation of Electronic Materials

Microstructural and compositional characterisation of electronic materials in support of the development of GaAs, GaN and GaSb based multilayer device structures is described. Electron microscopy techniques employing nanometer and sub-nanometer scale imaging capability of structure and chemistry have been widely used to characterise various aspects of electronic and optoelectronic device structures such as InGaAs quantum dots, InGaAs pseudomorphic (pHEMT) and metamorphic (mHEMT) layers and the ohmic metallisation of GaAs and GaN high electron mobility transistors, nichrome thin film resistors, GaN heteroepitaxy on sapphire and silicon substrates, as well as InAs and GaN nanowires. They also established convergent beam electron diffraction techniques for determination of lattice distortions in III-V compound semiconductors, EBSD for crystalline misorientation studies of GaN epilayers and high-angle annular dark field techniques coupled with digital image analysis for the mapping of composition and strain in the nanometric layered structures. Also, in-situ SEM experiments were performed on ohmic metallisation of pHEMT device structures. The established electron microscopy expertise for electronic materials with demonstrated examples is presented

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe