Approximate Message Passing-based Compressed Sensing Reconstruction with Generalized Elastic Net Prior

In this paper, we study the compressed sensing reconstruction problem with generalized elastic net prior (GENP), where a sparse signal is sampled via a noisy underdetermined linear observation system, and an additional initial estimation of the signal (the GENP) is available during the reconstruction. We first incorporate the GENP into the LASSO and the approximate message passing (AMP) frameworks, denoted by GENP-LASSO and GENP-AMP respectively. We then focus on GENP-AMP and investigate its parameter selection, state evolution, and noise-sensitivity analysis. A practical parameterless version of the GENP-AMP is also developed, which does not need to know the sparsity of the unknown signal and the variance of the GENP. Simulation results with 1-D data and two different imaging applications are presented to demonstrate the efficiency of the proposed schemes

Memory bites and games - environmental and mental elements affect brain health for elderly

This bachelor’s thesis is part of the Research and Development (R&D) project “Memory Bites and Games” at Lahti University of Applied Sciences. The aim of that project is to develop a new social game application which can be web-based or/and mobile based.  The function of the application is helping to train and maintain brain health, to identify early signs of cognitive malfunction or impairment.    The purpose: This literature review is to find out what are the mental, environmental elements which have affected on the development of brain diseases and how these aspects should be taken into account in preventing them. The method: Data was collected through systematic database search. The study consisted of international studies and articles were selected by peer reviewed. A qualitative literature review was used as the research method, inductive content analysis was used for data analysis. The findings: From environmental perspective, there are six factors containing lifestyle, residency, social networks, games, radiation and pollution were found to affect elder adult’s brain health. From mental perspective, five factors including lifestyle, social status, medical intervention, disease and art were found to dedicate to the quality of brain health of elderly people. In conclusion: The literature review is involved in environmental and mental elements which effect brain health of elderly people, the follow-up study about physical and cognitive elements effecting brain health is recommended in future.Tämä opinnäytetyö on osa tutkimus ja kehitys projektia " Muistin Puraisut ja Pelit " Lahden ammattikorkeakoulussa. Kyseisen projektin tavoitteena on kehittää uusi sosiaalinen pelisovellus joka voi olla selain ja/tai kännykkä pohjainen sovellus. Ohjelman tarkoituksena on auttaa harjoittelemaan, ylläpitämänä aivojen kuntoa ja tunnistamaan varhaisia merkkejä kognitiivisestä heikentymisestä tai vajaatoiminnasta. Tarkoitus: Tämä kirjallisuuskatsaus selvittää mitkä ovat psyykkisiä ja ympäristöllisiä tekijöitä, jotka vaikuttavat aivosairauksien kehittymiseen ja mitenkä nämä pitäisi huomioida niiden ehkäisemiseksi. Menetelmä: Tiedot kerättiin systemaattisesti etsimällä tietokannasta. Tutkimus sisälti kansainvälisiä tutkimuksia ja artikkeleita, jotka valittiin Melinda, Masto-finna, Academic search elite (EBSCO), Medic ja PubMed tietokannoista. Kuvaistavaa kirjallisuuskatsomusta käytettiin aineiston lähteenä ja määrällistä sisällön analyysia käytettiin analysoinnissa. Havainnot: Ympäristöllisesti on kuusi tekijää. Elämäntapa, asuinpaikka, sosiaaliset verkostot, pelit, säteily ja saaste havaittiin vaikuttavan vanhuksen aivojen terveyteen. Psyykkisiä tekijöitä oli viisi tekijää. elämäntavat, sosiaalinen asema, lääkinnällinen apu, taudit ja taide havaittiin vaikuttavan vanhusten aivoterveyteen. Yhteenveto: Kirjallisuuskatsauksessa liittyvät ympäristöllisiin ja psyykkisiin tekijöihin jotka vaikuttavat vanhusten aivojen terveyteen. Jatkotutkimus fyysisestä ja kognitiiviststa tekijöistä, jotka vaikuttavat aivojen terveyteen on suositeltavaa tulevaisuudessa.        

LMC: Fast Training of GNNs via Subgraph Sampling with Provable Convergence

The message passing-based graph neural networks (GNNs) have achieved great success in many real-world applications. However, training GNNs on large-scale graphs suffers from the well-known neighbor explosion problem, i.e., the exponentially increasing dependencies of nodes with the number of message passing layers. Subgraph-wise sampling methods -- a promising class of mini-batch training techniques -- discard messages outside the mini-batches in backward passes to avoid the neighbor explosion problem at the expense of gradient estimation accuracy. This poses significant challenges to their convergence analysis and convergence speeds, which seriously limits their reliable real-world applications. To address this challenge, we propose a novel subgraph-wise sampling method with a convergence guarantee, namely Local Message Compensation (LMC). To the best of our knowledge, LMC is the {\it first} subgraph-wise sampling method with provable convergence. The key idea of LMC is to retrieve the discarded messages in backward passes based on a message passing formulation of backward passes. By efficient and effective compensations for the discarded messages in both forward and backward passes, LMC computes accurate mini-batch gradients and thus accelerates convergence. We further show that LMC converges to first-order stationary points of GNNs. Experiments on large-scale benchmark tasks demonstrate that LMC significantly outperforms state-of-the-art subgraph-wise sampling methods in terms of efficiency

Graded extensions in K[Q, sigma]

Let V be a total valuation ring of a division ring K, Q be the additive group of the rational numbers, Aut(K) be the group of automorphisms of K. Let sigma be a group homomorphism from Q to Aut(K). Let K[Q, sigma ] be the skew group ring of Q over K. In this paper, we classify graded extensions of V in K[Q, sigma] into two types and study the structure of them

Multi-microjoule GaSe-based mid-infrared optical parametric amplifier with an ultra-broad idler spectrum covering 4.2-16 {\mu}m

We report a multi-microjoule, ultra-broadband mid-infrared optical parametric amplifier based on a GaSe nonlinear crystal pumped at ~2 {\mu}m. The generated idler pulse has a flat spectrum spanning from 4.5 to 13.3 {\mu}m at -3 dB and 4.2 to 16 {\mu}m in the full spectral range, with a central wavelength of 8.8 {\mu}m. The proposed scheme supports a sub-cycle Fourier-transform-limited pulse width. A (2+1)-dimensional numerical simulation is employed to reproduce the obtained idler spectrum. To our best knowledge, this is the broadest -3 dB spectrum ever obtained by optical parametric amplifiers in this spectral region. The idler pulse energy is ~3.4 {\mu}J with a conversion efficiency of ~2% from the ~2 {\mu}m pump to the idler pulse.Comment: 5 pages, 5 figure

Quantum Cloning Machines and the Applications

No-cloning theorem is fundamental for quantum mechanics and for quantum information science that states an unknown quantum state cannot be cloned perfectly. However, we can try to clone a quantum state approximately with the optimal fidelity, or instead, we can try to clone it perfectly with the largest probability. Thus various quantum cloning machines have been designed for different quantum information protocols. Specifically, quantum cloning machines can be designed to analyze the security of quantum key distribution protocols such as BB84 protocol, six-state protocol, B92 protocol and their generalizations. Some well-known quantum cloning machines include universal quantum cloning machine, phase-covariant cloning machine, the asymmetric quantum cloning machine and the probabilistic quantum cloning machine etc. In the past years, much progress has been made in studying quantum cloning machines and their applications and implementations, both theoretically and experimentally. In this review, we will give a complete description of those important developments about quantum cloning and some related topics. On the other hand, this review is self-consistent, and in particular, we try to present some detailed formulations so that further study can be taken based on those results.Comment: 98 pages, 12 figures, 400+ references. Physics Reports (published online