nils-herrmann/clean_scirepeval huggingface dataset:
Robust point cloud registration based on topological graph and Cauchy weighted [formula omitted] norm
Year: 2020

Point Cloud Registration (PCR) is a fundamental and important issue in photogrammetry and computer vision. Its goal is to find rigid transformations that register multiple 3D point sets. This paper proposes a robust and efficient PCR method based on topological graph and Cauchy weighted lq norm. Our method does not require initializations and is highly robust to outliers and partial overlaps. It contains two major steps: (1) correspondence based coarse registration, which is called Weighted lq Coarse Registration (WlqCR) In the WlqCR method, we represent feature point sets as topological graphs and transform the point matching problem to an edge matching problem. We build a mathematical model for edge correspondence maximization. We also present an edge voting strategy to distinguish potential correct matches from mismatches. Then, we define a concept called edge vector, which has a property that it is invariant to translations. Based on this property, six Degrees of Freedoms (DoF) PCR problem can be simplified into two three DoF subproblems, i.e. rotation estimation and translation estimation. (2) fine registration based on Weighted lq Iterative Closest Point (WlqICP) We propose a new ICP method called WlqICP, which is much more robust to partial overlaps compared with traditional ICP. In both rotation estimation and WlqICP, we use a new Cauchy weighted lq norm (0<q<1) instead of l2 norm for object function construction, which has a high degree of robustness. Extensive experiments on both simulated and real data demonstrate the power of the proposed method, i.e. our method is more robust (is able to tolerate up to 99% of outliers) and much faster than compared state of the art methods (WlqCR is almost two orders of magnitude faster than RANdom SAmple Consesus (RANSAC) and its variants under 95% of outliers) The source code will be made publicly available in http:/www.escience.cn/people/lijiayuan/index.html.
Phase transformations and stress evolution during laser beam welding and post heat treatment of TiAl alloys
Year: 2015

g TiAl material is an attractive alternative candidate for aerospace and automotive applications because of its low density, high specific yield strength and high creep and oxidation resistance. It has been used successfully in the manufacture of low pressure turbine blades in the GEnx engine, which represents a major advance in propulsion efficiency, with a 20% reduction in fuel consumption, a 50% reduction in noise, and an 80% reduction in NOx emissions compared with prior engines of the same class. In future, g TiAl will most likely be applied as a structural material in the combustion turbine of aircraft; for this purpose, the challenge of determining a method for the proper joining of this material must be met. Laser beam welding is considered to be a promising joining method. However, because of the low ductility and fracture toughness of g TiAl alloys at ambient temperature, cracks are frequently observed in welding seams. The high cooling rate further reduces the weldability of the alloy, as a large amount of brittle phase and high residual stresses are formed. Thus, there are four problems that must be solved: (1) How can a crack free TiAl butt joint be produced? (2) How can the microstructural and mechanical properties of the weld be improved? (3) How do the phases transform during welding? (4) How to perform a fast and reliable welding? The objective of this thesis is to methodically address these challenges. First, because of the intrinsic brittleness of the alloy, several heat treatments using a furnace and a defocused laser are applied to heat the alloys above the brittle to ductile transition temperature and reduce the cooling rate. The butt joint welds are investigated via radiography and found to be free of cracks. Second, the task is the modification of the microstructural and mechanical properties of the welds. The grain refinement induced by borides, which is widely exploited during casting, is suppressed by the high cooling rate. Additionally, a large amount of a2 phase and residual stress are detrimental to the weld. Thus, post weld heat treatments are applied to the aswelded specimens to refine the grain size, modify the microstructure and relieve the residual
Development and thermal performance of wood HPDE PCM nanocapsule floor for passive cooling in building
Year: 2019

Cooling demand in the building sector is growing rapidly; thermal energy storage systems using phase change materials (PCM) can be a very useful way to improve the building thermal performance. This work shows the benefits of PCM when incorporated in wood fiber polymer composite as floor cooling system using nano encapsulated PCMs. The wood plastic NPCM composites were produced using compression molding process and its mechanical and thermal properties were investigated. Two dynamic simulators were employed to investigate synthesized composites thermal performance. Increasing NPCM content in WPC showed that the fluctuations of the simulator temperature was decreased while the heat fluxes through the floor was increased. The variations of ambient maximum temperature have little effect on the air temperature of the simulator with 40% PCM which indicates that the amount of PCM was enough for studied environmental condition. Field experiments were performed using two medium scale test houses located on Tehran Iran. It can be concluded that using NPCM helps to reduce heating and cooling demand. Moreover, the natural night ventilation by opening windows reduced the number of hours that the temperature is above 23degC from 499 h/year in case1 (without opening) to 255 h/year in case 2(with opening) This means that natural night ventilation could help reduce the overheating period to about 50% with the use of NPCM.
SiC Partikul Boyutunun Yerinde Sentezleme Yontemi ile Uretilen HfB2 SiC Kompozitlerinin Mikroyapisal, Mekanik ve Oksidasyon Ozellikleri Uzerine Etkisi
Year: 2020

In situ synthesis and densification of hafnium diboride silicon carbide (HfB2 SiC) ceramic composites were studied by the spark plasma sintering (SPS) method using HfO2, B, and SiC as starting powders. Influence of SiC particle size ~2 mm and ~10 mm) on mechanical properties and oxidation resistance of in situ composites were extensively investigated. According to the achieved results, the highest densification ~95 TD) was obtained with fine SiC particle reinforcement. The measured Vickers hardness and fracture toughness of the composites containing fine SiC were 14.3 GPa and 5.42 MPa.m, respectively. The fracture mode changed from transgranular cleavage to a mixed mode, and the crack deflection was believed to be the primary toughening mechanism. From oxidation test result, the composite with fine SiC particles exhibited more inhomogeneous oxide scales compared to that of coarse SiC containing composite.
Generalized Micro Service Architecture for Web Based Database Management Systems
Venue: 2020 20th International Conference on Advances in ICT for Emerging Regions (ICTer)
Year: 2020

In web based database management systems, execution of multiple select queries or the queries requesting a large amount of data records from a single database management service via http requests is heavily affected by the performance of the database management service, rather than database engine. Although almost every popular Relational Database Management System (RDBMS) is designed with an architecture to provide higher efficiency, ultimately a single database management service will read the database and serve the results through http in the common scenario. So, a drastic performance reduction is visible while serving the http requests with the fetched data from the databases.This research examines the efficiency difference between micro service architecture and mono service architecture for web based database management systems by analyzing the time taken to get the response with data for READ operations with different record sizes. This research proposes a simple and generic web service architecture in managing HTTP requests which require fetching data from the underlying SQL adhering the micro service concepts.
Data Annotation and Multi Emotion Classification for Social Media Text
Venue: 2020 International Conference on Communication and Signal Processing (ICCSP)
Year: 2020

In recent years, sentiment or emotion analysis has become a key research area due to its vast potential applications in getting insights from social media comments, marketing, political science, psychology, human computer interaction, and artificial intelligence. Emotion analysis deals with identifying the emotions in any given data such as text, speech, or image. The current work proposes to identify and associate social media text to multiple emotions with varying degrees. The data collection and annotation process employed in the proposed work is a combination of manual and semi supervised annotation method where each tweet is mapped to a six dimensional emotion vector. Totally six human emotions such as happy, sad, anger, disgust, surprise, and fear are considered for emotion tagging. Word mover's distance (WMD) based on twitter word embeddings (word2vec) is proposed to develop a labelled dataset in the current work. A set of classifiers is developed on the labelled dataset to identify emotions at the tweet level in any given text data. In the current work, KNN, tree based, and neural network classifiers are developed.
Matrix permeability of reservoir rocks, Ngatamariki geothermal field, Taupo Volcanic Zone, New Zealand
Venue: Geothermal Energy
Year: 2018

The Taupo Volcanic Zone (TVZ) hosts 23 geothermal fields, seven of which are currently utilised for power generation. Ngatamariki geothermal field (NGF) is one of the latest geothermal power generation developments in New Zealand (commissioned in 2013) located approximately 15 km north of Taupo. Samples of reservoir rocks were taken from the Tahorakuri Formation and Ngatamariki Intrusive Complex, from five wells at the NGF at depths ranging from 1354 to 3284 m. The samples were categorised according to whether their microstructure was pore or microfracture dominated. Image analysis of thin sections impregnated with an epoxy fluorescent dye was used to characterise and quantify the porosity structures and their physical properties were measured in the laboratory. Our results show that the physical properties of the samples correspond to the relative dominance of microfractures compared to pores. Microfracture dominated samples have low connected porosity and permeability, and the permeability decreases sharply in response to increasing confining pressure. The pore dominated samples have high connected porosity and permeability, and lower permeability decrease in response to increasing confining pressure. Samples with both microfractures and pores have a wide range of porosity and relatively high permeability that is moderately sensitive to confining pressure. A general trend of decreasing connected porosity and permeability associated with increasing dry bulk density and sonic velocity occurs with depth; however, variations in these parameters are more closely related to changes in lithology and processes such as dissolution and secondary veining and re crystallisation. This study provides the first broad matrix permeability characterisation of rocks from depth at Ngatamariki, providing inputs for modelling of the geothermal system. We conclude that the complex response of permeability to confining pressure is in part due to the intricate dissolution, veining, and recrystallization textures of many of these rocks that lead to a wide variety of pore shapes and sizes. While the laboratory results are relevant only to similar rocks in the Taupo Volcanic Zone, the relationships they highlight are applicable to other geothermal fields, as well as rock mechanic applications to, for example, aspects of volcanology, landslide stabilisation, mining, and tunnelling at depth.
The Quantum Approximate Optimization Algorithm Needs to See the Whole Graph: Worst Case Examples
Year: 2020

The Quantum Approximate Optimization Algorithm can be applied to search problems on graphs with a cost function that is a sum of terms corresponding to the edges. When conjugating an edge term, the QAOA unitary at depth p produces an operator that depends only on the subgraph consisting of edges that are at most p away from the edge in question. On random d regular graphs, with d fixed and with p a small constant time log n, these neighborhoods are almost all trees and so the performance of the QAOA is determined only by how it acts on an edge in the middle of tree. Both bipartite random d regular graphs and general random d regular graphs locally are trees so the QAOA's performance is the same on these two ensembles. Using this we can show that the QAOA with (d 1){2p} n^A$ for any $A<1$ can only achieve an approximation ratio of 1/2 for Max Cut on bipartite random d regular graphs for d large. For Maximum Independent Set, in the same setting, the best approximation ratio is a d dependent constant that goes to 0 as d gets big.
HABILITATION A DIRIGER DES RECHERCHES
Year: 2016

L'industrie de l'assainissement, du demantelement et du declassement (A&D2) est une industrie mature. En France, pour les installations du CEA, les resultats obtenus sur le site de Grenoble le montrent et les avancees technologiques comme la mise en service du systeme Maestro, equipement de decoupe de forte puissance a retour d'effort, le confirment. Les procedes sont deployes dans des contextes complexes et sont adaptes pour repondre a des configurations techniques diffe rentes reacteur, laboratoires de recherche, usines de retraitement de combustibles uses. L'efficience des procedes s'appuie sur la maitrise de trois phases generiques (fonctions de haut niveau) de l'industrie manufacturiere 1) la gestion des entreposages, 2) le traitement (mise au gabarit physique et radiologique) puis 3) le conditionnement des dechets (produit) Le point commun est la gestion d'un terme source (Bq) Chaque etape du procede d'A&D2 est maitrisee a partir de l'evaluation des niveaux radiologiques. L'instrumentation nucleaire est donc une fonction majeure dans le deploiement et la maitrise des processus d'A&D2. En exploitation, l'essentiel des equipements de caracterisation radiologique et physico chimique des materiels en fin de cycle de vie est concentree sur le colis de dechets. Ces equipements sont maintenus dans la phase d'A&D2. Ils sont completes par des moyens de mesure et controle distribues sur l'ensemble des procedes, de l'element sur pied ou en entreposage au colis final. L'architecture fonctionnelle et logique de cette instrumentation prend la forme d'un diagramme d'instrumentation ou les equipements sont d'abord utiles a caracteriser les scenes a demanteler, puis a maitriser les procedes d'assainissement et de demantelement, et, en fin de ligne, les colis ou l'installation liberee des contraintes radiologiques. La mesure des rayonnements gamma et neutronique domine les techniques d'analyse non destructives. La spectrometrie gamma reste la technique de reference en A&D. Son deploiement a ete facilite grace a l'avenement des detecteurs fonctionnant a tempe rature ambiante (CdZnTe, LaBr3. Pour les scenes complexes, le resultat du traitement du spectre gamma est combine avec des techniques de localisation des points de concentration. Le traitement combine des resultats de mesure est assure par l'exploitation de methodes numeriques pour le trace des courbes de rendement et l'estimation de l'incertitude associee a la grandeur d'interet. La caracterisation des dechets de l'A&D2 a renforce l'utilisation des methodes couplees analyse physico chimique, spectrometrie gamma, imageur gamma et comptage neutronique, methodes qui se propagent sur l'ensemble de la ligne de production des de chets et pour le declassement des installations. Ce nouveau concept de chaine de production integrale ouvre de nombreuses voies de travail, technologiques et scientifiques.
S WAL: Fast and Efficient Write Ahead Logging for Mobile Devices
Venue: IEEE Transactions on Consumer Electronics
Year: 2018

A crash consistency mechanism of database application (hereinafter DBMS for short) imposes an enormous burden on the journaling process of the file system (e.g. JBD2) in that it employs regular files on the file system to persistently preserve the application's journal data with synchronous system calls. Unfortunately, much of the previous research is impractical in real world scenarios because they require changing a lot of source lines of code in multiple software layers of the software stack or using special hardware (e.g. the transactional flash storage or NVM technologies) In this paper, we propose a new journal mode of DBMS, called S WAL, which compresses the raw data journaled by the database to alleviate both the redundant journaling operations and harmful write amplification. We believe that S WAL is a practical way to support application level crash consistency on the existing mobile devices because only a few lines of DBMS code need to be changed, without the need to employ special hardware. We demonstrate the effectiveness of S WAL by running four popular mobile applications on the latest smartphone. Our evaluation results show that S WAL considerably outperforms existing journal modes of DBMS in all cases. In the best case, S WAL reduces the elapsed time by up to $7.5\times$ more than the PERSIST mode and by up to 51% more than the traditional WAL mode.
Assessing breast cancer risk models in Marin County, a population with high rates of delayed childbirth.
Venue: Clinical breast cancer
Year: 2014

This study was designed to compare the Breast Cancer Risk Assessment Tool (BCRAT; Gail) International Breast Intervention Study (IBIS; Tyrer Cuzick) and BRCAPRO breast cancer risk assessment models using data from the Marin Women's Study, a cohort of women within Marin County, California, with high rates of breast cancer, nulliparity, and delayed childbirth. Existing models have not been well validated in these high risk populations.  Discrimination was assessed using the area under the receiver operating characteristic curve (AUC) and calibration by estimating the ratio of expected to observed (E/O) cases. The models were assessed using data from 12,843 participants, of whom 203 had developed cancer during a 5 year period. All tests of statistical significance were 2 sided.  The IBIS model achieved an AUC of 0.65 (95% confidence interval [CI] 0.61 0.68) compared with 0.62 (95% CI, 0.59 0.66) for BCRAT and 0.60 (95% CI, 0.56 0.63) for BRCAPRO. The corresponding estimated E/O ratios for the models were 1.08 (95% CI, 0.95 1.25) 0.81 (95% CI, 0.71 0.93) and 0.59 (95% CI, 0.52 0.68) In women with age at first birth 30 years, the AUC for the IBIS, BCRAT, and BRCAPRO models was 0.69 (95% CI, 0.62 0.75) 0.63 (95% CI, 0.56 0.70) and 0.62 (95% CI, 0.56 0.68) and the E/O ratio was 1.15 (95% CI, 0.89 1.47) 0.81 (95% CI, 0.63 1.05) and 0.53 (95% CI, 0.41 0.68) respectively.  The IBIS model was well calibrated for the high risk Marin mammography population and demonstrated the best calibration of the 3 models in nulliparous women. The IBIS model also achieved the greatest overall discrimination and displayed superior discrimination for women with age at first birth 30 years.
An evidential Markov decision making model
Venue: Inf. Sci.
Year: 2018

The sure thing principle and the law of total probability are basic laws in classic probability theory. A disjunction fallacy leads to the violation of these two classical laws. In this paper, an Evidential Markov (EM) decision making model based on Dempster Shafer (D S) evidence theory and Markov modelling is proposed to address this issue and model the real human decision making process. In an evidential framework, the states are extended by introducing an uncertain state which represents the hesitance of a decision maker. The classical Markov model can not produce the disjunction effect, which assumes that a decision has to be certain at one time. However, the state is allowed to be uncertain in the EM model before the final decision is made. An extra uncertainty degree parameter is defined by a belief entropy, named Deng entropy, to assignment the basic probability assignment of the uncertain state, which is the key to predict the disjunction effect. A classical categorization decision making experiment is used to illustrate the effectiveness and validity of EM model. The disjunction effect can be well predicted and the free parameters are less compared with the existing models.
Adipose Derived Stem Cells for Corneal Wound Healing after Laser Induced Corneal Lesions in Mice
Venue: Journal of clinical medicine
Year: 2017

The aim of our study was to assess the clinical effectiveness of topical adipose derived stem cell (ADSC) treatment in laser induced corneal wounds in mice by comparing epithelial repair, inflammation, and histological analysis between treatment arms. Corneal lesions were performed on both eyes of 40 mice by laser induced photorefractive keratectomy. All eyes were treated with topical azythromycin bid for three days. Mice were divided in three treatment groups (n 20) which included: control, stem cells and basic serum; which received topical treatment three times daily for five consecutive days. Biomicroscope assessments and digital imaging were performed by two masked graders at 30, 54, 78, 100, and 172 h to analyze extent of fluorescein positive epithelial defect, corneal inflammation, etc. Immunohistochemical techniques were used in fixed eyes to assess corneal repair markers Ki67, a Smooth Muscle Actin (a SMA) and E Cadherin. The fluorescein positive corneal lesion areas were significantly smaller in the stem cells group on days 1 (p 0.05) 2 (p 0.02) and 3. The stem cell treated group had slightly better and faster re epithelization than the serum treated group in the initial phases. Comparative histological data showed signs of earlier and better corneal repair in epithelium and stromal layers in stem cell treated eyes, which showed more epithelial layers and enhanced wound healing performance of Ki67, E Cadherin, and a SMA. Our study shows the potential clinical and histological advantages in the topical ADSC treatment for corneal lesions in mice.
UTILISATION DES SYSTEMES D'INFORMATIONS GEOGRAPHIQUES (SIG) ET INTERPOLATION POUR LA CARACTERISATION DE LA POLLUTION DES EAUX SOUTERRAINES EN MILIEU RURAL DE LA VILLE DE SEBAA AYOUNE (BASSIN DE SAIS, MAROC)
Year: 2019

La presente etude vise a cartographier, identifier et evaluer l'impact de la pollution sur la qualite des eaux souterraines en milieu rural de la ville de Sebaa Ayoune (Region Fes Meknes, Maroc) Elle est basee sur l'utilisation des Systemes d'Information Geographique (SIG) et sur l'evolution spatio temporelle des parametres physico chimiques et bacteriologiques des eaux etudiees. Afin d'atteindre cet objectif, nous avons effectue un suivi bacteriologique saisonnier pour les annees 2016 et 2017, et un suivi annuel pour les parametres physicochimiques (2016 2017) Les analyses ont porte sur 6 parametres physicochimiques (turbidite, conductivite electrique, NH 4 NO 3 SO 4 2 Cl et deux germes bacteriologiques indicateurs de la pollution fecale Escherichia coli et les enterocoques intestinaux Les cartes thematiques de cette pollution montrent un etat de bonne de qualite pour la masse d'eau etudiee.