Data-driven approach to machine condition prognosis using least square regression trees

Machine fault prognosis techniques have been considered profoundly in the recent time due to their profit for reducing unexpected faults or unscheduled maintenance. With those techniques, the working conditions of components, the trending of fault propagation, and the time-to-failure are forecasted precisely before they reach the failure thresholds. In this work, we propose an approach of Least Square Regression Tree (LSRT), which is an extension of the Classification and Regression Tree (CART), in association with one-step-ahead prediction of time-series forecasting technique to predict the future conditions of machines. In this technique, the number of available observations is firstly determined by using Cao’s method and LSRT is employed as prognosis system in the next step. The proposed approach is evaluated by real data of low methane compressor. Furthermore, the comparison between the predicted results of CART and LSRT are carried out to prove the accuracy. The predicted results show that LSRT offers a potential for machine condition prognosis

Improving search order for reachability testing in timed automata

Standard algorithms for reachability analysis of timed automata are sensitive to the order in which the transitions of the automata are taken. To tackle this problem, we propose a ranking system and a waiting strategy. This paper discusses the reason why the search order matters and shows how a ranking system and a waiting strategy can be integrated into the standard reachability algorithm to alleviate and prevent the problem respectively. Experiments show that the combination of the two approaches gives optimal search order on standard benchmarks except for one example. This suggests that it should be used instead of the standard BFS algorithm for reachability analysis of timed automata

Constraining higher-spin S-matrices

There are various no-go theorems that tightly constrain the existence of local higher-spin theories with non-trivial S-matrix in flat space. Due to the existence of higher-spin Yang-Mills theory with non-trivial scattering amplitudes, it makes sense to revisit Weinberg's soft theorem - a direct consequence of the Lorentz invariance of the S-matrix that does not take advantage of unitarity and parity invariance. By working with the chiral representation - a representation originated from twistor theory, we show that Weinberg's soft theorem can be evaded and non-trivial higher-spin S-matrix is possible. In particular, we show that Weinberg's soft theorem is more closely related to the number of derivatives in the interactions rather than spins. We also observe that all constraints imposed by gauge invariance of the S-matrix are accompanied by polynomials in the soft momentum of the emitted particle where the zeroth order in the soft momentum is charge conservation law.Comment: 26 pages, 4 figures, published versio

Toward a twistor action for chiral higher-spin gravity

A covariant twistor action for chiral higher-spin theory in (A)dS is constructed in terms of a holomorphic Chern-Simons theory on twistor space. The action reproduces all known cubic vertices of chiral higher-spin gravity in flat space. Parts of the spacetime action of chiral higher-spin gravity in flat space are also obtained by working in the Woodhouse gauge.Comment: 5 page

Deep Neural Architectures for End-to-End Relation Extraction

The rapid pace of scientific and technological advancements has led to a meteoric growth in knowledge, as evidenced by a sharp increase in the number of scholarly publications in recent years. PubMed, for example, archives more than 30 million biomedical articles across various domains and covers a wide range of topics including medicine, pharmacy, biology, and healthcare. Social media and digital journalism have similarly experienced their own accelerated growth in the age of big data. Hence, there is a compelling need for ways to organize and distill the vast, fragmented body of information (often unstructured in the form of natural human language) so that it can be assimilated, reasoned about, and ultimately harnessed. Relation extraction is an important natural language task toward that end. In relation extraction, semantic relationships are extracted from natural human language in the form of (subject, object, predicate) triples such that subject and object are mentions of discrete concepts and predicate indicates the type of relation between them. The difficulty of relation extraction becomes clear when we consider the myriad of ways the same relation can be expressed in natural language. Much of the current works in relation extraction assume that entities are known at extraction time, thus treating entity recognition as an entirely separate and independent task. However, recent studies have shown that entity recognition and relation extraction, when modeled together as interdependent tasks, can lead to overall improvements in extraction accuracy. When modeled in such a manner, the task is referred to as end-to-end relation extraction. In this work, we present four studies that introduce incrementally sophisticated architectures designed to tackle the task of end-to-end relation extraction. In the first study, we present a pipeline approach for extracting protein-protein interactions as affected by particular mutations. The pipeline system makes use of recurrent neural networks for protein detection, lexicons for gene normalization, and convolutional neural networks for relation extraction. In the second study, we show that a multi-task learning framework, with parameter sharing, can achieve state-of-the-art results for drug-drug interaction extraction. At its core, the model uses graph convolutions, with a novel attention-gating mechanism, over dependency parse trees. In the third study, we present a more efficient and general-purpose end-to-end neural architecture designed around the idea of the table-filling paradigm; for an input sentence of length n, all entities and relations are extracted in a single pass of the network in an indirect fashion by populating the cells of a corresponding n by n table using metric-based features. We show that this approach excels in both the general English and biomedical domains with extraction times that are up to an order of magnitude faster compared to the prior best. In the fourth and last study, we present an architecture for relation extraction that, in addition to being end-to-end, is able to handle cross-sentence and N-ary relations. Overall, our work contributes to the advancement of modern information extraction by exploring end-to-end solutions that are fast, accurate, and generalizable to many high-value domains

Higher spin gravity

Diese Dissertation ist den Quantenaspekten von Gravitationen höherer Spins (GRAHSs) und den ihnen zugrundeliegenden algebraischen Strukturen gewidmet. Theorien höherer Spins enthalten unendlichdimensionale Symmetrien, die mächtig genug sein sollten, um keine relevanten Gegenterme zuzulassen. Aus diesem Grund wird seit langem erwartet, dass GRAHSs endlich, oder zumindest renormierbar sind. Sobald gezeigt ist, dass diese Eigenschaft tatsächlich realisiert wird, macht sie Theorien höherer Spins zu interessanten Quantengravitationsmodellen. Wenn das keine-Gegenterme-Argument funktioniert, reduziert sich das Problem, eine quantenkonsistente Theorie höherer Spins zu konstruieren, bemerkenswerterweise auf das Problem, ein konsistentes klassisches Modell von GRAHS zu finden. Eine der interessantesten Klassen von GRAHSs ist die chirale GRAHS, die sowohl in der Minkowski- als auch in der AdS-Raumzeit existiert. Sie ist momentan die einzige Theorie mit propagierenden Feldern höherer Spins und einer recht einfachen Wirkung. Die Theorie ist auf perturbativer Ebene lokal. Die Wirkung der chiralen GRAHS ist in der Lichtkegel-Eichung bekannt und vermeidet alle Theoreme, welche die Existenz einer Theorie höherer Spins im flachen Raum verbieten. Wir studieren die Struktur der Quantenkorrekturen in der chiralen GRAHS im Minkowskiraum im Detail. Wir zeigen, dass aufgrund einer nichttrivialen Kürzung unter den Feynmandiagrammen dank einer spezifischen Form der Wechselwirkungen (dem Kopplungs-Verschwörungs-Mechanismus), alle Baumniveau-Amplituden verschwinden; wir analysieren im Detail zwei-, drei- und vier-Punkt Einschleifenamplituden und zeigen, dass diese UV-konvergent sind. Mit Hilfe von Unitaritätsschnitten berechnen wir die komplette n-Punkt Einschleifenamplitude und zeigen, dass sie aus drei Faktoren besteht: (i) der Einschleifenamplitude in QCD oder SDYM mit allen Helizitäten plus; (ii) einem bestimmten kinematischen Verzierungsfaktor für höhere Spins; (iii) einem rein numerischen Faktor der Gesamtanzahl der Freiheitsgrade. Im Kontext von AdS/KFT wird vermutet, dass GRAHSs dual zu recht einfachen konformen Feldtheorien (KFTs) sind: zu freien und kritischen Vektormodellen (Typ-A), freien Fermionen und Gross–Neveu-Modellen (Typ-B) und, allgemeiner, zu Chern–Simons-Materie- Theorien. Wir studieren im Detail die Vakuum-Einschleifenkorrekturen in verschiedenen Theorien höherer Spins in der anti-de Sitter (AdS) Raumzeit. Für die Typ-A-Theorie in AdSd+1 beweisen wir die Vermutung, dass die freie Energie für alle ganzzahligen Spins verschwindet und der freien Energie einer Kugel eines freien Skalarfeldes für alle geraden Spins gleicht. Wir erweitern dieses Resultat auf alle nicht-ganzzahligen Dimensionen und reproduzieren insbesondere die freie-Energie-Korrektur zur 4 − ε Wilson–Fisher KFT als einen Einschleifeneffekt in der Typ-A-Theorie auf AdS5−ε. Wir berechnen ebenfalls die Beiträge fermionischer Felder höherer Spins, die für supersymmetrische GRAHS relevant sind. Es wird gezeigt, dass diese exakt mit der Vorhersage der KFT übereinstimmen. Der Beitrag bestimmter Felder gemischter Symmetrie, die in Typ-B GRAHS vorkommen, wird ebenfalls berechnet. Der letztere Beitrag führt (in geraden Raumzeitdimensionen) auf eine Frage, die zu beantworten bleibt. Freie KFTs haben unendlichdimensionale globale Symmetrien, die in Algebras höherer Spins manifestiert sind. Die holographisch dualen GRAHSs sollten im Prinzip komplett durch diese Symmetrie bestimmt sein. Deshalb ist die einzige Information, die wir benötigen, um eine Theorie höherer Spins in AdS zu konstruieren, eine Algebra höherer Spins, die aus ihrer dualen freien KFT extrahiert werden kann. In dieser Dissertation rekonstruieren wir die Typ-A GRAHS in AdS5 auf der Ebene der formal konsistenten klassischen Bewegungsgleichungen (formale GRAHS).This dissertation is dedicated to the quantum aspects of higher spin gravities (HSGRAs) and to their underlining algebraic structures. Higher-spin theories are governed by infinite-dimensional symmetries called higher-spin symmetries. Higher-spin symmetry should be powerful enough to leave no room for any relevant counterterms. Therefore, higher spin gravities have long been expected to be finite or at least renormalizable. This feature, once shown to be realized, makes higher-spin theories interesting toy models of Quantum Gravity. Remarkably, if the no-counterterm argument works, the problem of constructing a quantum consistent higher-spin theory downgrades to a problem of finding a consistent classical model of higher-spin gravity. One of the most interesting classes of HSGRAs is chiral HSGRA, which exists both in Minkowski and AdS spacetime. It is the only theory at present with propagating massless higher spin fields and a rather simple action. The theory is perturbatively local. The action of the chiral theory is known in the light-cone gauge and and avoids all No-Go theorems that forbid the existence of higher-spin theories in flat space. We study in detail the structure of quantum corrections in the Minkowski Chiral HSGRA. We show that all tree-level amplitudes vanish, which is due to a nontrivial cancellation among all Feynman diagrams thanks to the specific form of the interactions (coupling conspiracy mechanism); we analyze in detail two-, three- and four-point one-loop amplitudes and show that they are UV-convergent. Using unitarity cuts we compute the complete one-loop n-point amplitude and show that it consists of three factors: (i) all-plus helicity one-loop amplitude in QCD or SDYM; (ii) a certain kinematical higher spin dressing factor; (iii) a purely numerical factor of the total number of degrees of freedom. In the context of AdS/CFT, HSGRAs are conjectured to be dual to rather simple conformal field theories (CFT): free and critical vector models (Type-A), free fermion and Gross-Neveu models (Type-B) and, more generally, to Chern-Simons Matter theories. We study in detail vacuum one-loop corrections in various higher-spin theories in anti-de Sitter (AdS) spacetime. For the Type-A theory in AdSd+1 we prove the conjecture that the free energy vanishes for all integer spins and is equal to the sphere free energy of one free scalar field for all even spins. We extend this result to non-integer dimension and, in particular, reproduce the free energy correction to the 4 − ε Wilson-Fisher CFT as a one-loop effect in the Type- A theory on AdS5−ε. We also compute the contribution of fermionic higher spin fields that are relevant for supersymmetric HSGRA. These are shown to match precisely with the prediction of the CFT. The contribution of certain mixed-symmetry fields that appear in Type-B HSGRA is also computed. The latter leads to a puzzle (in even spacetime dimension) that remains to be resolved. Free CFTs have infinite-dimensional global symmetries manifested in higher spin algebras. The holographic dual HSGRAs should, in principle, be completely determined by this higher spin symmetry. Therefore, to construct a higher-spin theory in AdS, the only initial data we need is a higher spin algebra extracted from its free CFT dual. In this thesis, we reconstructed the Type-A HSGRA in AdS5 at the level of formally consistent classical equations of motion (Formal HSGRA)

The Analysis of the Tendency of the Vietnamese Media: Researching on the Construction of Chinese Tourist Image Based on “VnExpress”

China is now becoming a fundamental market for the prosperity and growth of the world’s tourism economy. It promotes the rapid development of foreign tourism and brings some influences to social life. Chinese tourists are highly concerned with foreign media at home and abroad; the Vietnamese Media is the same. Based on the theoretical framework, this paper analyzes the Chinese tourists report towards the Vietnamese Media “VnExpress” 2018 and discusses the construction of Chinese tourists’ image from the three views of macroscopic, the middle, and microcosmic of the news text framework. From there, it shows the tendency and prejudice of the Vietnamese media. The study found that “VnExpress” has a clear tendency; the image of Chinese tourists is full of negatives. At the same time, it indirectly involves events on political issues; Vietnamese media also maintain strong political sensitivity. Moreover, it emphasizes the integrity of Vietnam’s territorial sovereignty, the particularity of history and culture, and strengthening the sense of identity of Vietnamese readers