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A theoretical model for pattern discovery in visual analytics

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Visual Informatics 2021年第1期5卷 23-42页

作者： Natalia Andrienko Gennady Andrienko Silvia Miksch Heidrun Schumann Stefan Wrobel fraunhofer institute iais Sankt-AugustinGermany City University of LondonLondonUK TU Wien ViennaAustria University of Rostock RostockGermany University of Bonn BonnGermany

The word‘pattern’frequently appears in the visualisation and visual analytics literature,but what do we mean when we talk about patterns?We propose a practicable definition of the concept of a pattern in a data distribution as a combination of multiple interrelated elements of two or more data components that can be represented and treated as a unified *** theoretical model describes how patterns are made by relationships existing between data *** the types of these relationships,it is possible to predict what kinds of patterns may *** demonstrate how our model underpins and refines the established fundamental principles of *** model also suggests a range of interactive analytical operations that can support visual analytics workflows where patterns,once discovered,are explicitly involved in further data analysis.

关键词： Visual analytics Data distribution Pattern Abstraction Data organisation Data arrangement Data variation Pattern discovery

THERMOCHROMIC EFFECTS OF LEUCO DYES STUDIED IN POLYPROPYLENE

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Chinese Journal of Polymer Science 2006年第4期24卷 363-368页

作者： Arno Seeboth Detlef L(o|¨)tzsch Elvira Potechius Renate Vetter fraunhofer institute for Applied Polymer Research

A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-（1-n-butyl-2-methyl-3-indolyl）-phthalide as dyes and l-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.

关键词： Thermochromism Dyes Extrusion UV-Vis spectroscopy.

Process Design for Hybrid Sheet Metal Components

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1518-1524页

作者： Rico Haase Roland Müller Dirk Landgrebe Peter Scholz Matthias Riemer fraunhofer institute for Machine Tools and Forming Technology IWU

The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme strength-toweight and stiffness-to-weight ratio. Besides monolithic materials such as high-strength or light metals, in particular metal–plastic composite sheets are able to provide outstanding mechanical properties. Thus, the adaption of conventional, wellestablished forming methods for the processing of hybrid sheet metals is a current challenge for the sheet metal working industry. In this work, the planning phase for a conventional sheet metal forming process is studied aiming at the forming of metal–plastic composite sheets. The single process steps like material characterization, FE analysis, tool design and development of robust process parameters are studied in detail and adapted to the specific properties of metal–plastic composites. In material characterization, the model of the hybrid laminate needs to represent not only the mechanical properties of the individual combined materials, but also needs to reflect the behaviour of the interface zone between *** on experience, there is a strong dependency on temperature as well as strain rate. While monolithic materials show a moderate anisotropic behaviour, loads on laminates in different directions generate different strain states and completely different failure modes. During the FE analysis, thermo-mechanic and thermo-dynamic effects influence the temperature distribution within tool and work pieces and subsequently the forming behaviour. During try out and production phase,those additional influencing factors are limiting the process window even more and therefore need to be considered for the design of a robust forming process. A roadmap for sheet metal forming adjusted to metal–plastic composites is presented in this paper.

关键词： Characterization Hybrids Interface Layered structures Processing Sheet forming

Forensic Readiness: Emerging Discipline for Creating Reliable and Secure Digital Evidence

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Journal of Harbin institute of Technology(New Series) 2015年第1期22卷 1-8页

作者： Barbara Endicott-Popovsky Nicolai Kuntze Carsten Rudolph institute of Technology University of Washington fraunhofer institute of Technology

Traditional approaches to digital forensics reconstruct events within digital systems that often are not built for the creation of evidence; however,there is an emerging discipline of forensic readiness that examines what it takes to build systems and devices that produce digital data records for which admissibility is a requirement. This paper reviews the motivation behind research in this area,a generic technical solution that uses hardware-based security to bind digital records to a particular state of a device and proposed applications of this solution in concrete,practical scenarios. Research history in this area,the notion of secure digital evidence and a technical solution are discussed. A solution to creating hardware-based security in devices producing digital evidence was proposed in 2012. Additionally,this paper revises the proposal and discusses three distinct scenarios where forensic readiness of devices and secure digital evidence are relevant. It shows,how the different requirements of the three scenarios can be realized using a hardware-based solution. The scenarios are:lawful interception of voice communication,automotive black box,precise farming. These three scenarios come from very distinctive application domains. Nevertheless,they share a common set of security requirements for processes to be documented and data records to be stored.

关键词： digital forensics forensic readiness calibration d

A learning-based approach for efficient visualization construction

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Visual Informatics 2022年第1期6卷 14-25页

作者： Yongjian Sun Jie Li Siming Chen Gennady Andrienko Natalia Andrienko Kang Zhang College of Intelligence and Computing Tianjin UniversityChina School of Data Science Fudan UniversityChina fraunhofer institute iais Germany City University London UK Beijing Normal University-Hong Kong Baptist University United International College China

We propose an approach to underpin interactive visual exploration of large data volumes by training Learned Visualization Index(LVI).Knowing in advance the data,the aggregation functions that are used for visualization,the visual encoding,and available interactive operations for data selection,LVI allows to avoid time-consuming data retrieval and processing of raw data in response to user’s ***,LVI directly predicts aggregates of interest for the user’s data *** demonstrate the efficiency of the proposed approach in application to two use cases of spatio-temporal data at different scales.

关键词： Learned index Neural network Visualization index Interactive exploration Spatiotemporal visualization

Predicting an Optimal Virtual Data Model for Uniform Access to Large Heterogeneous Data

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Data Intelligence 2024年第2期6卷 504-530页

作者： Chahrazed B.Bachir Belmehdi Abderrahmane Khiat Nabil Keskes LabRI-SBA Enterprise Information SystemsESI-SBA InstituteFraunhofer IAISAlgeriaGermany

The growth of generated data in the industry requires new efficient big data integration approaches for uniform data access by end-users to perform better business *** virtualization systems,including Ontology-Based Data Access(ODBA)query data on-the-fly against the original data sources without any prior data *** approaches by design use a fixed model e.g.,TABULAR as the only Virtual Data Model-a uniform schema built on-the-fly to load,transform,and join relevant *** other data models,such as GRAPH or DOCUMENT,are more flexible and,thus,can be more suitable for some common types of queries,such as join or nested *** queries are hard to predict because they depend on many criteria,such as query plan,data model,data size,and *** address the problem of selecting the optimal virtual data model for queries on large datasets,we present a new approach that(1)builds on the principal of OBDA to query and join large heterogeneous data in a distributed manner and(2)calls a deep learning method to predict the optimal virtual data model using features extracted from SPARQL ***-implementation of our approach currently leverages state-of-the-art Big Data technologies,Apache-Spark and Graphx,and implements two virtual data models,GRAPH and TABULAR,and supports out-of-the-box five data sources models:property graph,document-based,e.g.,wide-columnar,relational,and tabular,stored in Neo4j,MongoDB,Cassandra,MySQL,and CSV *** experiments show that our approach is returning the optimal virtual model with an accuracy of 0.831,thus,a reduction in query execution time of over 40%for the tabular model selection and over 30%for the graph model selection.

关键词： Data Virtualization Big Data OBDA Deep Learning

Improvement on straightness of metal bar based on straightening stroke-deflection model

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Science China(Technological Sciences) 2009年第7期52卷 1866-1873页

作者： LEOPOLD Juergen fraunhofer institute for Machine Tools and Forming Technology Chemnitz Germany

The straightening technics is one of important means to improve the straightness of metal bar. A novel way of predicting the straightening stroke is proposed based on mathematical methods and bending experimental and numerical simulation. The experimental and numerical simulation is conducted by following the mathematical load-stroke model of press straightening process under the elastic-plastic theory. For the linear guide rails, as an example, the stroke-deflection model focusing on the straightening stroke prediction can be achieved by contrasting and integrating the bending experimental results and finite element methods (FEM) simulation data. And then the formula for predicting the straightening stroke is presented based on the precise straightening stroke-deflection model. The stroke prediction formula with high precision can be applied to the straightening stroke prediction in the high straightness metal bar manufacturing process and automatic straightening machine conveniently.

关键词： straightness straightening stroke deflection stroke prediction metal bar

Pressureless sintering of ZrC with variable stoichiometry

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Journal of Advanced Ceramics 2017年第2期6卷 165-175页

作者： Katrin SCH(O)NFELD Hans-Peter MARTIN Alexander MICHAELIS fraunhofer institute for Ceramic Technologies and Systems IKTS Dresden Germany

This paper presents the experiments on the synthesis of zirconium carbide (ZrC) using carbothermal reduction of zirconia (ZrO2).The ratio of ZrO2∶C is used to adapt ZrCxOy with x＜ 1 or ZrC + *** modification of ZrCxOy and the total carbon amount allows the use of pressureless sintering method in combination with sintering temperatures ≤ 2000 ℃.Fully densified ZrC products are *** relevant details of ZrC formation are investigated by X-ray diffraction (XRD).The sintered products are characterized by XRD,field emission scanning electron microscopy (FESEM),as well as mechanical and electrical *** and FESEM investigations show that ZrCxOy is formed during the manufacturing *** grain size and additional zirconia or carbon are related to the ZrO2∶C ratio of the starting powder *** strength up to 300 MPa,Young's modulus up to 400 GPa,fracture toughness up to 4.1 MPa·m1/2,and electrical resistance at room temperature around 10-4 Ω.cm are reached by the pressureless sintered ZrC.

关键词： zirconium carbide (ZrC) carbothermal reduction sintering mechanical properties electrical properties

Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 297-310页

作者： Chuang Liu Dongzhi Sun Xianfeng Zhang Florence Andrieux Tobias Gersterc School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China fraunhofer institute for Mechanics of Materials(IWM) 79108 FreiburgGermany fraunhofer institute for High Speed Dynamics Ernst-Mach-Institute(EMI)79104 FreiburgGermany

Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive *** study the mechanical behavior of a typical ductile cast iron(GJS-450)with nodular graphite,uni-axial quasi-static and dynamic tensile tests at strain rates of 10^(-4),1,10,100,and 250 s^(-1)were carried *** order to investigate the influence of stress state on the deformation and fracture parameters,specimens with various geometries were used in the *** strain curves and fracture strains of the GJS-450 alloy in the strain rate range of 10^(-4)to 250 s^(-1)were obtained.A strain rate-dependent plastic flow model was proposed to describe the mechanical behavior in the corresponding strain-rate *** available damage model was extended to take the strain rate into account and calibrated based on the analysis of local fracture *** with the proposed plastic flow model and the damage model were conducted to observe the deformation and fracture *** results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 *** predictions with the proposed plastic flow and damage models at various strain rates agree well with the experimental results,which illustrates that the rate-dependent plastic flow and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain *** proposed plastic flow and damage models can be used to describe the deformation and fracture analysis of materials with similar properties.

关键词： Dynamic behavior of materials Strain rate dependency Damage model Voce model Cast iron