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"base mark"
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A new filter‐based pseudo‐negative‐stiffness control for base‐isolated buildings
2017
Summary A filter‐based pseudo‐negative‐stiffness (FPNS) control is proposed for seismic control of base‐isolated structures. The control algorithm is designed to produce a negative stiffness friction damping force with a gradual change at velocity switches, so that it is potential to prevent structures from experiencing significant jerks especially under earthquakes rich of high‐frequency components. The control algorithm requires information only on device's displacement. The effect of the control parameters on structural performance is studied and the optimal combination of control parameters is obtained with the consideration of control efficiency and the economy of control force. The superior performance of an active control system employing the FPNS control algorithm over that employing the conventional PNS control algorithm is verified. A semi‐active control design, MC‐FPNS, is developed to produce the control force of the FPNS control algorithm by MR dampers. The effectiveness and robustness of the MC‐FPNS control system are investigated through numerical analysis of the base‐isolated benchmark problem under earthquakes scaled to different intensity levels. The proposed MC‐FPNS control system is shown to be effective to not only prevent the isolator from failure but also improve the isolation functionality for a variety of earthquakes with different frequency contents and intensity levels. Moreover, the MC‐FPNS control system is capable of suppressing transference of high‐frequency components of ground motions to the superstructure. Copyright © 2016 John Wiley & Sons, Ltd.
Journal Article
Non-Invasive On-Site XRF and Raman Classification and Dating of Ancient Ceramics: Application to 18th and 19th Century Meissen Porcelain (Saxony) and Comparison with Chinese Porcelain
by
Simsek Franci, Gulsu
,
Gerken, Mareike
,
Gironda, Michele
in
18th century
,
19th century
,
Antiques
2023
The authentication and dating of rare ceramics is generally carried out using subjective criteria, mainly based on visual interpretation. However, the scientific study and evaluation of the materials used could contribute objectively. The analytical data relating to the major and minor elements of the coloring agents of the decoration or the base marks, and the characteristics of the raw materials (related to geology and ore processing), can be obtained on the conservation site non-invasively using a pXRF instrument and the phases formed may be identified using Raman microspectroscopy. This approach is applied to 28 objects assigned to the production of the Meissen Factory, from the collection of the Musée National de Céramique, Cité de la Céramique, Sèvres. They have polychromic or blue-and-white decorations and are supposed to have been produced in the 18th and 19th centuries. Some have a production date that has been perfectly established, others may have been produced using an earlier mold, or even have been decorated on an unknown date different from that of the firing of the biscuit. The combination of several classification criteria concerning the type of glaze, previously identified in the study of French and Chinese 17th and 18th centuries productions, i.e., the elements associated with cobalt present in the mark or the blue decoration and the relative levels of impurities of the glaze matrix, both characteristic of the raw materials and giving a strong XRF signal, leads to the identification of groups of homogeneous objects (respectively, counting seven, three, two and two objects for which at least four out of five criteria are identical); the other objects present too many differences to be considered as having been produced with the same raw materials. The first group brings together almost all the objects with a reliable pedigree made before ~1750, but includes two objects with decoration types closer to those of the 1800s. The comparison of the pXRF signals confirms the possibility of identifying the use of European ingredients for the production of painted enamels in the Qing dynasty.
Journal Article
Saw marks in bone: A preliminary empirical study to inform decision making and best practice
by
Bolton, Matthew S.
,
Raymond, Jennifer
,
Meakin, Georgina E.
in
Best practice
,
Body fluids
,
Bone
2023
Forensic toolmark examiners compare marks between those observed on an item/surface and those made by a reference implement, such as a particular tool or weapon, to provide an opinion of the likelihood of common origin. It is widely accepted that such comparison opinions need to be underpinned by empirical research, and this study aimed to add to the knowledge base relied upon when developing and comparing saw marks in bone, a substrate encountered in body dismemberment cases. Porcine bones were used as a human proxy; they were either fresh with residual soft tissue and bodily fluids present (‘wet’) to replicate dismembered bones shortly post-mortem, or processed to remove soft tissue and moisture content (‘dry’) to represent cases of dismemberment after an extended period of decomposition and exposure. The bones were cut using one implement of each of five classes: hand saw, mitre saw, reciprocating saw, oscillating saw, and serrated knife. They were cut, either completely through (except for serrated knife), giving two surfaces per cut to examine, or to a depth up to 3 mm (false starts). Five replicates per combination of bone condition, saw, and cut type gave 130 bone samples. These were then cleaned and cast using Isomark Silicone Polymer Compound or Mikrosil, giving 260 cast samples. All bone and cast samples were photographed, examined for various class characteristic markers, and specific markers measured. No significant differences between Isomark and Mikrosil casts were observed when compared side-by-side, demonstrating suitability of both materials for casting of saw marks on bone. Although saw marks presented more class characteristic markers on dry than wet bones, calculations of tooth distances and measurements of kerf width (KW) from marks did not significantly differ between bone conditions, with exception of the reciprocating saw that produced false start marks with significantly larger minimum KW on wet than dry samples. Further analysis supported that tooth distances on marks made by hand and oscillating saws are sufficiently accurate for the determination of saw teeth per inch (TPI). However, one tooth distance on marks made by reciprocating saws did not accurately represent TPI. Finally, examination of presence or absence of class characteristic markers on each saw mark demonstrated consistent variation between saw classes. These results enabled the development of exclusion-based decision trees, and a reference database (available on request), for use by toolmark examiners in their evaluation of saw types based on class characteristic markers observed in cut bone.
•Both Isomark and Mikrosil are suitable for casting saw marks in bone.•Significantly more class characteristics observed in saw marks on dry than wet bone.•Variation in presence of characteristics in marks made by different saw classes.•Decision trees given for distinguishing between marks made by different saw classes.•Preliminary image database of casts and saw marks on bone available on request.
Journal Article
Intelligent Biometric Group Hand Tracking (IBGHT) database for visual hand tracking research and development
by
Rosdi, Bakhtiar Affendi
,
Asaari, Mohd. Shahrimie Mohd
,
Suandi, Shahrel Azmin
in
Algorithms
,
Analysis
,
Applied sciences
2014
With the increase of innovations in vision-based hand gesture interaction system, new techniques and algorithms are being developed by researchers. However, less attention has been paid on the scope of dismantling hand tracking problems. There is also limited publicly available database developed as benchmark data to standardize the research on hand tracking area. For this purpose, we develop a versatile hand gesture tracking database. This database consists of 60 video sequences containing a total of 15,554 RGB color images. The tracking sequences are captured in different situations ranging from an easy indoor scene to extremely high challenging outdoor scenes. Complete with annotated ground truth data, this database is made available on the web for the sake of assisting other researchers in the related fields to test and evaluate their algorithms based on standard benchmark data.
Journal Article
Dual-Signal Feature Spaces Map Protein Subcellular Locations Based on Immunohistochemistry Image and Protein Sequence
2023
Protein is one of the primary biochemical macromolecular regulators in the compartmental cellular structure, and the subcellular locations of proteins can therefore provide information on the function of subcellular structures and physiological environments. Recently, data-driven systems have been developed to predict the subcellular location of proteins based on protein sequence, immunohistochemistry (IHC) images, or immunofluorescence (IF) images. However, the research on the fusion of multiple protein signals has received little attention. In this study, we developed a dual-signal computational protocol by incorporating IHC images into protein sequences to learn protein subcellular localization. Three major steps can be summarized as follows in this protocol: first, a benchmark database that includes 281 proteins sorted out from 4722 proteins of the Human Protein Atlas (HPA) and Swiss-Prot database, which is involved in the endoplasmic reticulum (ER), Golgi apparatus, cytosol, and nucleoplasm; second, discriminative feature operators were first employed to quantitate protein image-sequence samples that include IHC images and protein sequence; finally, the feature subspace of different protein signals is absorbed to construct multiple sub-classifiers via dimensionality reduction and binary relevance (BR), and multiple confidence derived from multiple sub-classifiers is adopted to decide subcellular location by the centralized voting mechanism at the decision layer. The experimental results indicated that the dual-signal model embedded IHC images and protein sequences outperformed the single-signal models with accuracy, precision, and recall of 75.41%, 80.38%, and 74.38%, respectively. It is enlightening for further research on protein subcellular location prediction under multi-signal fusion of protein.
Journal Article
Hidden Markov Model-Based Smart Annotation for Benchmark Cyclic Activity Recognition Database Using Wearables
by
Eskofier, Bjoern M.
,
Sprager, Sebastijan
,
Martindale, Christine F.
in
activity recognition
,
benchmark database
,
cyclic activities
2019
Activity monitoring using wearables is becoming ubiquitous, although accurate cycle level analysis, such as step-counting and gait analysis, are limited by a lack of realistic and labeled datasets. The effort required to obtain and annotate such datasets is massive, therefore we propose a smart annotation pipeline which reduces the number of events needing manual adjustment to 14%. For scenarios dominated by walking, this annotation effort is as low as 8%. The pipeline consists of three smart annotation approaches, namely edge detection of the pressure data, local cyclicity estimation, and iteratively trained hierarchical hidden Markov models. Using this pipeline, we have collected and labeled a dataset with over 150,000 labeled cycles, each with 2 phases, from 80 subjects, which we have made publicly available. The dataset consists of 12 different task-driven activities, 10 of which are cyclic. These activities include not only straight and steady-state motions, but also transitions, different ranges of bouts, and changing directions. Each participant wore 5 synchronized inertial measurement units (IMUs) on the wrists, shoes, and in a pocket, as well as pressure insoles and video. We believe that this dataset and smart annotation pipeline are a good basis for creating a benchmark dataset for validation of other semi- and unsupervised algorithms.
Journal Article
A benchmark image database of isolated Bangla handwritten compound characters
2014
In the present work, we present a benchmark image database of isolated handwritten Bangla compound characters, used in the standard Bangla literature. A thorough survey over more than 2 million Bangla words has revealed that there exist around 334 compound characters in Bangla script. Of which, only around 171 character classes form unique pattern shapes, and some of these classes are often written in multiple styles. Altogether, 55,278 isolated character images, belonging to 199 different pattern shapes, are collected using three different data collection modalities. The database is divided into training and test sets in 4:1 ratio for each pattern class, by considering a balanced distribution of shapes from different modalities. A convex hull and quadtree-based feature set has been designed, and the test set recognition performance is reported with the support vector machine classifier. We have achieved a recognition accuracy of 79.35 % on the test database consisting of 171 character classes. The complete compound character image database is freely available as CMATERdb 3.1.3.3 from the website http://code.google.com/p/cmaterdb/, which may facilitate research on handwritten character recognition, especially related to Bangla form document processing systems.
Journal Article
Efficient storage of heterogeneous geospatial data in spatial databases
2019
The no-schema approach of NoSQL document stores is a tempting solution for importing heterogenous geospatial data to a spatial database. However, this approach means sacrificing the benefits of RDBMSes, such as existing integrations and the ACID principle. Previous comparisons of the document-store and table-based layout for storing geospatial data favours the document-store approach but does not consider importing data that can be segmented into homogenous datasets. In this paper we propose “The Heterogeneous Open Geodata Storage (HOGS)” system. HOGS is a command line utility that automates the process of importing geospatial data to a PostgreSQL/PostGIS database. It is developed in order to compare the performance of a traditional storage layout adhering to the ACID principle, and a NoSQL-inspired document store. A collection of eight open geospatial datasets comprising 15 million features was imported and queried in order to compare the differences between the two storage layouts. The results from a quantitative experiment are presented and shows that large amounts of open geospatial data can be stored using traditional RDBMSes using a table-based layout without any performance penalties.
Journal Article
Comparison of adaptive magnetorheological elastomer isolator and elastomeric isolator in near-field and far-field earthquakes
2021
Magnetorheological Elastomers (MREs) are widely used in the development of smart isolators and absorbers due to their stiffness and damping adaptability. This study investigates the performance of MRE isolators and elastomeric isolators in both near-field and far-field earthquakes in base-isolated benchmark buildings. All earthquakes were simultaneously investigated in two horizontal directions on the horizontal plane. Vertical earthquakes were not considered in the dynamic analysis of base-isolated benchmark buildings. The effect of bilateral interaction was also examined while making an isolator model. Moreover, the behaviors of MRE isolators and Magnetorheological (MR) dampers were compared. To this end, three control systems including adaptive isolator, passive isolator, and semi-active MR damper were taken into account. The results showed that the MRE isolator outperformed the elastomeric isolator in near-field earthquakes due to its variable stiffness and damping. In addition, the semi-active MR damper for both far-field and near-field earthquakes significantly reduced base displacement; however, it increased floor accelerations, story drifts, and story shear. The results of this study showed that MRE isolator could be an appropriate substitute for MR damper. The MRE isolator could reduce base displacement without increasing other responses.
Journal Article
Mobile signature verification: feature robustness and performance comparison
by
Krish, Ram P.
,
Galbally, Javier
,
Martinez-Diaz, Marcos
in
Algorithms
,
automatic signature verification systems
,
Biometrics
2014
In this study, the effects of using handheld devices on the performance of automatic signature verification systems are studied. The authors compare the discriminative power of global and local signature features between mobile devices and pen tablets, which are the prevalent acquisition device in the research literature. Individual feature discriminant ratios and feature selection techniques are used for comparison. Experiments are conducted on standard signature benchmark databases (BioSecure database) and a state-of-the-art device (Samsung Galaxy Note). Results show a decrease in the feature discriminative power and a higher verification error rate on handheld devices. It is found that one of the main causes of performance degradation on handheld devices is the absence of pen-up trajectory information (i.e. data acquired when the pen tip is not in contact with the writing surface).
Journal Article