Robust Tensor Hypercontraction of the Particle-Particle Ladder Term in Equation-of-Motion Coupled Cluster Theory

One method of representing a high-rank tensor as a (hyper-)product of lower-rank tensors is the tensor hypercontraction (THC) method of Hohenstein et al. This strategy has been found to be useful for reducing the polynomial scaling of coupled-cluster methods by representation of a four dimensional tensor of electron-repulsion integrals in terms of five two-dimensional matrices. Pierce et al. have already shown that the application of a robust form of THC to the particle-particle ladder term (PPL) reduces the cost of this term in couple-cluster singles and doubles (CCSD) from $\mathcal{O} (N^6)$ to $\mathcal{O} (N^5)$ with negligible errors in energy with respect to the density-fitted variant. In this work we have implemented the least-squares variant of THC (LS-THC) which does not require a non-linear tensor factorization, including the robust form (R-LS-THC), for the calculation of the excitation and electron attachment energies using equation-of-motion coupled cluster methods EOMEE-CCSD and EOMEA-CCSD, respectively. We have benchmarked the effect of the R-LS-THC-PPL approximation on excitation energies using the comprehensive QUEST database and the accuracy of electron attachment energies using the NAB22 database. We find that errors on the order of 1 meV are achievable with a reduction in total calculation time of approximately $5\times$

The Greedy pipe Toolset Manual (Version 1.0)

Chip Multi-Processors(CMPs) are now available in a variety of systems. They provide the opportunity to achieve high computational performance by exploiting application-level parallelism within a single chip form factor. In the communications environment, network processors (NPs) are often designed around CMP architectures and, in this context, the processors may be used in a pipelined manner. This leads to the issue of scheduling tasks on such processor pipelines. A tool and algorithm called Greedy pipe has been developed that determines the nearly optimal schedules for such multiprocessor pipelines. The tool offers a user friendly interface, with easily installable, portable and high-performance design. This report contains a description of the Greedy pipe tool set (release1.0), including the tool retrieval, installation and usage instructions

Approximately Minwise Independence with Twisted Tabulation

A random hash function $h$ is $\varepsilon$-minwise if for any set $S$, $|S|=n$, and element $x\in S$, $\Pr[h(x)=\min h(S)]=(1\pm\varepsilon)/n$. Minwise hash functions with low bias $\varepsilon$ have widespread applications within similarity estimation. Hashing from a universe $[u]$, the twisted tabulation hashing of P\v{a}tra\c{s}cu and Thorup [SODA'13] makes $c=O(1)$ lookups in tables of size $u^{1/c}$. Twisted tabulation was invented to get good concentration for hashing based sampling. Here we show that twisted tabulation yields $\tilde O(1/u^{1/c})$-minwise hashing. In the classic independence paradigm of Wegman and Carter [FOCS'79] $\tilde O(1/u^{1/c})$-minwise hashing requires $\Omega(\log u)$-independence [Indyk SODA'99]. P\v{a}tra\c{s}cu and Thorup [STOC'11] had shown that simple tabulation, using same space and lookups yields $\tilde O(1/n^{1/c})$-minwise independence, which is good for large sets, but useless for small sets. Our analysis uses some of the same methods, but is much cleaner bypassing a complicated induction argument.Comment: To appear in Proceedings of SWAT 201

A Review-Botnet Detection and Suppression in Clouds

Internet security problems remain a major challenge with many security concerns such as Internet worms, spam, and phishing attacks. Botnets is well-organized distributed network attacks, consist of a large number of bots that generate huge volumes of spam or launch Distributed Denial of Service (DDoS) attacks on victim hosts. Botnet attacks degrade the status of Internet security. Clouds provide botmaster with an ideal environment of rich computing resources where it can easily deploy or remove C&C server and perform attacks.  It is of vital importance for cloud service providers to detect botnet,  prevent attack,  and trace back to the botmaster.  It also becomes necessary to detect and suppress these bots to protect the clouds. This paper provides the various botnet detection techniques and the comparison of various botnet detection techniques. It also provides the botnet suppression technique in cloud. Keywords: Cloud computing, network security, botnet, botmmaster, botnet detection, botnet suppressio

Fuzzy Model For Human Face Expression Recognition

Facial expression recognition plays a vital and effective role within the interaction between man and computer. In this project, brand new system supported the mathematical logic is projected for this purpose. Fuzzy is one helpful approach for fuzzy classification, which might verify the intrinsic division in an exceedingly set of untagged knowledge and notice representatives for undiversified teams. This method acknowledges seven basic facial expressions particularly concern, surprise, happy, sad, disgust, Neutral and anger. For description of detail face facial features, Face Action writing (FACS) was style. First, we tend to gift a unique methodology for facial region extraction from static image. For determination of face effective areas is employed from integral projection curves. This methodology has high ability in intelligent choice of areas in facial features recognition system. Extracted face expression fed to fuzzy rule based mostly system for facial features recognition. Results of tests indicate that the projected theme for facial features recognition is powerful, with smart accuracy and generating superior results as compared to different approaches. DOI: 10.17762/ijritcc2321-8169.15052

Theoretical Investigation of The X-Ray Stark Effect in Small Molecules

We have studied the Stark effect in the soft x-ray region for various small molecules by calculating the field-dependent x-ray absorption spectra. This effect is explained in terms of the response of molecular orbitals (core and valence), the molecular dipole moment, and the molecular geometry to the applied electric field. A number of consistent trends are observed linking the computed shifts in absorption energies and intensities with specific features of the molecular electronic structure. We find that both the virtual molecular orbitals (valence and/or Rydberg) as well as the core orbitals contribute to observed trends in a complementary fashion. This initial study highlights the potential impact of x-ray Stark spectroscopy as a tool to study electronic structure and environmental perturbations at a sub-molecular scale.Comment: 33 pages, 9 figures, 7 tables, supporting information files availabl

Ab Initio Investigation of Intramolecular Charge Transfer States in DMABN by Calculation of Excited State X-ray Absorption Spectra

Dual fluorescence in 4-(dimethylamino)benzonitrile (DMABN) and its derivatives in polar solvents has been studied extensively for the past several decades. An intramolecular charge transfer (ICT) minimum on the excited state potential energy surface, in addition to the localized low-energy (LE) minimum, has been proposed as a mechanism for this dual fluorescence, with large geometric relaxation and molecular orbital reorganization a key feature of the ICT pathway. Herein, we have used both equation-of-motion coupled-cluster with single and double excitations (EOM-CCSD) and time-dependent density functional (TDDFT) methods to investigate the landscape of excited state potential energy surfaces across a number of geometric conformations proposed as ICT structures. In order to correlate these geometries and valence excited states in terms of potential experimental observables, we have calculated the nitrogen K-edge ground and excited state absorption spectra for each of the predicted "signpost" structures, and identified several key spectral features which could be used to interpret a future time-resolved x-ray absorption experiment

Effectiveness factors in bidispersed catalysts under conditions of catalyst fouling

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