cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Improving convergence in smoothed particle hydrodynamics simulations without pairing instability
Creators: name: Dehnen, Walter
name: Aly, Hossam
Publisher: name: arXiv
Year: 2012
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Computational Physics (physics.comp-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The numerical convergence of smoothed particle hydrodynamics (SPH) can be severely restricted by random force errors induced by particle disorder, especially in shear flows, which are ubiquitous in astrophysics. The increase in the number NH of neighbours when switching to more extended smoothing kernels at fixed resolution (using an appropriate definition for the SPH resolution scale) is insufficient to combat these errors. Consequently, trading resolution for better convergence is necessary, but for traditional smoothing kernels this option is limited by the pairing (or clumping) instability. Therefore, we investigate the suitability of the Wendland functions as smoothing kernels and compare them with the traditional B-splines. Linear stability analysis in three dimensions and test simulations demonstrate that the Wendland kernels avoid the pairing instability for all NH, despite having vanishing derivative at the origin (disproving traditional ideas about the origin of this instability; instead, we uncover a relation with the kernel Fourier transform and give an explanation in terms of the SPH density estimator). The Wendland kernels are computationally more convenient than the higher-order B-splines, allowing large NH and hence better numerical convergence (note that computational costs rise sub-linear with NH). Our analysis also shows that at low NH the quartic spline kernel with NH ~= 60 obtains much better convergence then the standard cubic spline.
description: substantially revised version, accepted for publication in MNRAS, 15 pages, 13 figures
Linear triglycerol-based fluorosurfactants show high potential for droplet-microfluidics-based biochemical assays
Creators: name: Chowdhury, Mohammad Suman
name: Zheng, Wenshan
name: Singh, Abhishek Kumar
name: Ong, Irvine Lian Hao
name: Hou, Yong
name: Heyman, John A.
name: Faghani, Abbas
name: Amstad, Esther
name: Weitz, David A.
name: Haag, Rainer
Publisher: name: Freie Universität Berlin
Year: 2021
Subjects: subject: fluorosurfactants
subject: biochemical assays
subject: microfluidic droplets
subject: 500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften

description: Fluorosurfactants have expanded the landscape of high-value biochemical assays in microfluidic droplets, but little is known about how the spatial geometries and polarity of the head group contribute to the performance of fluorosurfactants. To decouple this, we design, synthesize, and characterize two linear and two dendritic glycerol- or tris-based surfactants with a common perfluoropolyether tail. To reveal the influence of spatial geometry, we choose inter-droplet cargo transport as a stringent test case. Using surfactants with linear di- and triglycerol, we show that the inter-droplet cargo transport is minimal compared with their dendritic counterparts. When we encapsulated a less-leaky sodium fluorescent dye into the droplets, quantitatively, we find that the mean fluorescence intensity of the PFPE-dTG stabilized PBS-only droplets after 72 h was ∼3 times that of the signal detected in PBS-only droplets stabilized by PFPE-lTG. We also demonstrate that the post-functionalization of PFPE-lTG having a linear geometry and four hydroxy groups enables the ‘from-Droplet’ fishing of the biotin–streptavidin protein complex without the trade-off between fishing efficiency and droplet stability. Thus, our approach to design user-friendly surfactants reveals the aspects of spatial geometry and facile tunability of the polar head groups that have not been captured or exploited before.
Asthma and the Coronavirus Disease 2019 Pandemic: A Literature Review
Creators: name: Morais-Almeida, Mário
name: Pité, Helena
name: Aguiar, Rita
name: Ansotegui, Ignacio
name: Bousquet, Jean
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2020
Subjects: subject: COVID-19
subject: Allergy
subject: FOS: Clinical medicine
subject: Risk factors
subject: T2 inflammation
subject: Asthma
subject: Coronavirus disease 2019
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: Even though respiratory viruses are one of the most common triggers for asthma exacerbations, not all of these viruses affect patients equally. There is no strong evidence supporting that patients with asthma have a higher risk of becoming seriously ill from coronavirus disease 2019 (CO-VID-19), although recent reports from the USA and the UK suggest that asthma is much more common in children and adults with mild to severe COVID-19 than has previously been reported in Asia and in Europe. As in previous severe acute respiratory syndrome (SARS) outbreaks, patients with asthma, especially children, appear to be less susceptible to the coronavirus with a low rate of asthma exacerbations. A different expression of viral receptors and T2 inflammation can be responsible for different outcomes. Future studies focused on asthma and on other allergic disorders are needed to provide a greater understanding of the impact of underlying asthma and allergic inflammation on COVID-19 susceptibility and disease severity. However, for the moment, it is crucial that asthmatic patients maintain their controller medication, from inhaled corticosteroids to biologics, without making any dose adjustments on their own or stopping the medication. New data are emerging daily, rapidly updating our understanding of this novel coronavirus.
Studies toward the chemistry of N-confused oligopyrroles
Creators: name: Liu, Runchang
Publisher: name: University of British Columbia
Year: 2011

description: The objectives of this work were to explore the synthesis of linear N-confused (α-meso-β) oligopyrrolic pigments (variants of the corresponding α,α’-linear oligopyrrolic pigments), as well as to study the stability, optical properties and cyclization reactivity of these unprecedented N-confused oligopyrrole structures. MSA (methanesulfonic acid)-catalyzed condensation of aryl aldehydes with a variety of electron-withdrawing group (EWG)-substituted pyrroles to afford the corresponding meso-aryl N-confused diacyl dipyrromethanes was established. The directing effect of these EWGs for α-meso-β-linkage formation in N-confused dipyrromethanes was evaluated. The key for the successful transformation appears to depend upon the reactivities of the aldehyde and the electron-poor pyrrole substrates used. This novel one-pot synthetic approach for construction of α-meso-β-linkages between pyrroles is a substantial improvement over the classic multi-step synthesis (Chapter 2). Oxidation of an N-confused dipyrromethane to the corresponding conjugated dipyrrin system was explored by applying different oxidants. An efficient DDQ-mediated benzylic C-H activation for hydroxylation, alkoxylation and heteroarylation of meso-aryl DPMs (three different forms) to the corresponding meso-modified dipyrromethanes (DPMs) was established. Mechanistic study shows the reaction proceeds through a highly-unstable protonated dipyrrin intermediate (Chapter 3). Exploration of the oxidation process of the dipyrromethane allows discussion of the meso-steric effect observed during the oxidation, where substituents on the 2- and 6- positions of the meso-aryl group play important roles in producing and stabilizing the conjugated pyrrolemethene. N-confused (α-meso-β) dipyrrins were studied with regards to their synthesis, stability, reactivity, and configurational interconversion. The N-confused dipyrrinodiol can be imbedded as a building block into oligopyrrole frameworks efficiently with retention of the Z-syn N-confused moiety, which provides a concise way to create higher N-confused oligopyrrolic pigments (Chapter 4). Subsequently, in chapter 5, we report our synthesis of the conjugated N-confused oligopyrrolic macrocycle [12] tripyrrin (0.1.1) via an oxidative amination cyclization. As a macrocycle constructed purely of meso-aryl groups and pyrrole, N-confused [12] tripyrrin (0.1.1) was synthesized using an unprecedented head-to-tail cyclization. Also, linear N-confused tri- and tetrapyrrolemethenes were synthesized and fully characterized by X-ray analysis. Conversion of α,α’-linear oligopyrroles to their corresponding N-confused counterparts was achieved despite their presumed instability.
Young infants process prediction errors at the theta rhythm
Creators: name: Köster, Moritz
name: Langeloh, Miriam
name: Michel, Christine
name: Hoehl, Stefanie
Publisher: name: Freie Universität Berlin
Year: 2021
Subjects: subject: Infant cognition
subject: Theta rhythm
subject: Predictive processing
subject: Violation of expectation
subject: Electroencephalography
subject: 100 Philosophie und Psychologie::150 Psychologie::150 Psychologie

description: Examining how young infants respond to unexpected events is key to our understanding of their emerging concepts about the world around them. From a predictive processing perspective, it is intriguing to investigate how the infant brain responds to unexpected events (i.e., prediction errors), because they require infants to refine their predictions about the environment. Here, to better understand prediction error processes in the infant brain, we presented 9-month-olds (N = 36) a variety of physical and social events with unexpected versus expected outcomes, while recording their electroencephalogram (EEG). We found a pronounced response in the ongoing 4–5 Hz theta rhythm for the processing of unexpected (in contrast to expected) events, for a prolonged time window (2 s) and across all scalp-recorded electrodes. The condition difference in the theta rhythm was not related to the condition difference in infants’ event-related activity to unexpected (versus expected) events in the negative central (Nc) component (0.4–0.6 s), a component, which is commonly analyzed in infant violation of expectation studies using EEG. These findings constitute critical evidence that the theta rhythm is involved in the processing of prediction errors from very early in human brain development. We discuss how the theta rhythm may support infants’ refinement of basic concepts about the physical and social environment.
Dermatofluoroscopy Is Also for Redheads a Sensitive Method of Early Melanoma Detection
Creators: name: Leupold, Dieter
name: Szyc, Lukasz
name: Stankovic, Goran
name: Hofmann, Maja
name: Scholz, Matthias
name: Forschner, Andrea
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2020
Subjects: subject: Dermatofluoroscopy
subject: Redheads
subject: Melanoma
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: Background: Caucasians with red hair and fair skin have a remarkably increased risk of malignant melanoma compared to non-redhead Caucasians. Objectives: With the aim of a reliable melanoma diagnosis in redheads, the application of dermatofluoroscopy was analyzed in 16 patients with red hair. Most of them had been included in a clinical dermatofluoroscopy study for patients with the suspicion of melanoma. We examined whether the 25 lesions of the redheads showed the same characteristic melanin fluorescence spectra for dysplastic nevi and melanomas as those of non-redhead Caucasians or whether there was a different fluorescence pattern. This is important in view of the known significantly altered ratio of eumelanin to pheomelanin in the skin of redheads. Methods: More than 8,000 spatially resolved fluorescence spectra of 25 pigmented lesions were measured and analysed. The spectra were excited by the stepwise absorption of two 800-nm photons (principle of dermatofluoroscopy). Furthermore, the fluorescence spectra of eumelanin and pheomelanin in hair samples were determined in the same way. Results: The evaluation revealed that the melanin fluorescence spectra of dysplastic nevi and melanomas of redheads have the same spectral characteristics as those of non-redhead Caucasians. An accompanying result is that dermatofluoroscopy shows identical fluorescence spectra for eumelanin and pheomelanin. Conclusions: Dermatofluoroscopy proves to be a reliable diagnostic method also for redheads. Our results also explain our recent finding that there is a uniform fluorescence spectroscopic fingerprint for melanomas of all subtypes, which is of particular interest for hypomelanotic and apparently amelanotic melanomas containing pheomelanin.
Hammulator: Simulate Now - Exploit Later
Creators: name: Thomas, Fabian
name: Gerlach, Lukas
name: Schwarz, Michael
Publisher: name: CISPA
Year: 2023

description: Rowhammer, first considered a reliability issue, turned out to be a significant threat to the security of systems. Hence, several mitigation techniques have been proposed to prevent the exploitation of the Rowhammer effect. Consequently, attackers developed more sophisticated hammering and exploitation techniques to circumvent mitigations. Still, the development and testing of Rowhammer exploits can be a tedious process, taking multiple hours to get the bit flip at the correct location. In this paper, we propose Hammulator, an open-source rapid-prototyping framework for Rowhammer exploits. We simulate the Rowhammer effect using the gem5 simulator and DRAMsim3 model, with a parameterizable implementation that allows researchers to simulate various types of systems. Hammulator enables faster and more deterministic bit flips, facilitating the development of Rowhammer proof-of-concept exploits and defenses. We evaluate our simulator by reproducing 2 open-source Rowhammer exploits. We also evaluate 2 previously proposed mitigations, PARA and TRR, in our simulator. Additionally, our micro- and macrobenchmarks show that our simulator has a small average overhead in the range of 6.96 % to 10.21 %. Our results show that Hammulator can be used to compare Rowhammer exploits objectively by providing a consistent testing environment. Hammulator and all experiments and evaluations are open source, hoping to ease the research on Rowhammer.
Quantum Algorithms for Invariants of Triangulated Manifolds
Creators: name: Alagic, Gorjan
name: Bering, Edgar A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: Geometric Topology (math.GT)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: One of the apparent advantages of quantum computers over their classical counterparts is their ability to efficiently contract tensor networks. In this article, we study some implications of this fact in the case of topological tensor networks. The graph underlying these networks is given by the triangulation of a manifold, and the structure of the tensors ensures that the overall tensor is independent of the choice of internal triangulation. This leads to quantum algorithms for additively approximating certain invariants of triangulated manifolds. We discuss the details of this construction in two specific cases. In the first case, we consider triangulated surfaces, where the triangle tensor is defined by the multiplication operator of a finite group; the resulting invariant has a simple closed-form expression involving the dimensions of the irreducible representations of the group and the Euler characteristic of the surface. In the second case, we consider triangulated 3-manifolds, where the tetrahedral tensor is defined by the so-called Fibonacci anyon model; the resulting invariant is the well-known Turaev-Viro invariant of 3-manifolds.
description: 19 pages, 7 figures
Transnational solidarity among political elites: what determines support for financial redistribution within the EU in times of crisis?
Creators: name: Reinl, Ann-Kathrin
name: Giebler, Heiko
Publisher: name: Freie Universität Berlin
Year: 2021
Subjects: subject: solidarity
subject: European Union
subject: politicians
subject: economic crisis
subject: 300 Sozialwissenschaften::320 Politikwissenschaft::320 Politikwissenschaft

description: As a consequence of the European Economic Crisis, the European Union (EU) has implanted mechanisms to assist fellow member states facing economic difficulties. Despite an increasing academic interest in public preferences for such intra-EU solidarity measures, research has so far largely ignored individual characteristics that could possibly influence politicians’ views. In this paper, we look at politicians’ preferences for transnational solidarity and argue that these preferences depend on attitudes regarding socioeconomic issues as well as attitudes related to the EU. Moreover, we hypothesize that the relationship is moderated by responsibility attribution and the economic situation in a country. Using survey data of about 4000 politicians running for office in nine EU countries, we find that transnational solidarity is more common for socioeconomically left-wing and pro-EU politicians. Yet, attitudinal differences only cease to matter when the beneficiary state is perceived responsible for the crisis and economic problems at home are low.
The Human Interleukin-4 Treated Macrophage and Epithelial Wound Repair
Creators: name: Jayme, Timothy
Publisher: name: Cumming School of Medicine
Year: 2018
Subjects: subject: Education--Sciences

description: The murine interleukin-4 (IL-4) treated alternatively activated macrophage (M(IL4)) is known to have key roles in wound repair. Given that mucosal wound healing is the best indicator of long term remission for patients with inflammatory bowel disease (IBD), adoptive transfer of the M(IL4) in mice has been extensively studied as a therapeutic, and its beneficial outcome may be induced, in part, by M(IL4)s inducing wound healing. However, research has been extremely limited in translating these findings into human studies. Furthermore, helminth-derived soluble products can induce and enhance the M(IL4) phenotype in both mice and humans, however, its ability to enhance M(IL4) function is unknown. Therefore, my MSc research was designed to test the hypotheses that: 1) the human blood-derived M(IL4) can be an autologous cell immunotherapy for IBD by inducing mucosal wound repair; and, 2) in vitro treatment of M(IL4)s with an extract of the rat tapeworm, Hymenolepis diminuta (HdE), can enhance its capacity to wound repair. To my knowledge this is the first time that a human blood-derived M(IL4) (CD206highCCL18+CD14low) has been reported to promote colonic epithelial wound repair in an in vitro scratch assay: an ability dependent on TGF and prostaglandins. Furthermore, cryopreservation of human M(IL4)s, which could be an important process if used therapeutically, did not lose their ability to promote wound repair, although decreased M(IL4) markers were noted. Monocytes from patients with inactive Crohn’s disease or ulcerative colitis could be differentiated into M(IL4)s with the capacity to promote epithelial wound repair. Interestingly, M(IL4)s from patients with active Crohn’s disease and ulcerative colitis were more variable in their response to IL-4, and impaired M(IL4) activation (CD206lowCCL18+CD14low) correlated with an impaired ability to promote epithelial wound repair. This suggests that in vivo, M(IL4)s may have an important role in the resolution of inflammation by inducing mucosal wound repair in patients with active IBD. Finally, I could not find any direct evidence, in vitro, that HdE enhances the capacity of M(IL4)s to promote wound repair. Having defined the ability of the monocyte-derived M(IL4)s from healthy volunteers and patients with IBD to promote epithelial wound healing, my research lays the foundation for a more extensive investigation of the anti-inflammatory/pro-resolution activity of the human M(IL4), which could be used as an autologous transplant in a personalized medicine approach to IBD or other enteropathies.
Prediction of Anisotropic Single-Dirac-Cones in Bi${}_{1-x}$Sb${}_{x}$ Thin Films
Creators: name: Tang, Shuang
name: Dresselhaus, Mildred S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The electronic band structures of Bi${}_{1-x}$Sb${}_{x}$ thin films can be varied as a function of temperature, pressure, stoichiometry, film thickness and growth orientation. We here show how different anisotropic single-Dirac-cones can be constructed in a Bi${}_{1-x}$Sb${}_{x}$ thin film for different applications or research purposes. For predicting anisotropic single-Dirac-cones, we have developed an iterative-two-dimensional-two-band model to get a consistent inverse-effective-mass-tensor and band-gap, which can be used in a general two-dimensional system that has a non-parabolic dispersion relation as in a Bi${}_{1-x}$Sb${}_{x}$ thin film system.
A Common Metric for Self-Reported Severity of Personality Disorder
Creators: name: Zimmermann, Johannes
name: Müller, Steffen
name: Bach, Bo
name: Hutsebaut, Joost
name: Hummelen, Benjamin
name: Fischer, Felix
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2020
Subjects: subject: Personality disorder
subject: Item response theory
subject: Patient-reported outcomes
subject: Bifactor model
subject: Severity
subject: Personality functioning
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: Introduction:Dimensional models of personality disorders (PD) in the DSM-5 and ICD-11 share a focus on impairments in self and interpersonal functioning to represent the general features and severity of PD. This new perspective has led to the development of numerous measures for assessing individual differences in PD severity. While this improves choices for researchers and practitioners, it also poses the challenge of an increasing lack of standardization. Objective:The aim of this study is to establish a common metric across 6 widely used self-report measures of PD severity using item response theory models. Methods:849 participants completed a survey including the Inventory of Personality Organization - 16-item version (IPO-16), the Level of Personality Functioning Scale - Brief Form 2.0, the Level of Personality Functioning Scale - Self-Report, the Operationalized Psychodynamic Diagnosis - Structure Questionnaire Short Form, the Personality Inventory for DSM-5 - Brief Form Plus and the Standardized Assessment of Severity of Personality Disorder (SASPD). We fitted exploratory multidimensional graded response models and used bifactor rotation to extract a general factor across measures. Factor scores were linked to representative T scores using data from a representative survey of 2,502 participants who completed the IPO-16. Results:When using bifactor rotation in a 7-factor model, all items loaded positively on the general factor, and the general factor explained 65.5% of the common variance. With the exception of the SASPD, all measures provided highly discriminating items (factor loadings >0.70) for measuring the general factor and reached an acceptable reliability (>0.80) across a wide range of the latent continuum. We constructed a crosswalk table linking total scores of the 6 measures to each other and to representative T scores. Conclusions:Our results suggest that 6 different self-report measures of the severity of PD capture a strong common factor and can therefore be scaled along a single latent continuum. Our results may facilitate instrument-independent assessment of severity of PD and increase comparability across studies.
Proper motions of the Arches cluster with Keck-LGS Adaptive Optics: the first kinematic mass measurement of the Arches
Creators: name: Clarkson, Will
name: Ghez, Andrea
name: Morris, Mark
name: Lu, Jessica
name: Stolte, Andrea
name: McCrady, Nate
name: Do, Tuan
name: Yelda, Sylvana
Publisher: name: arXiv
Year: 2011
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report the first detection of the intrinsic velocity dispersion of the Arches cluster - a young (~2 Myr), massive (~10,000 Solar Mass) starburst cluster located near the Galactic center. This was accomplished using proper motion measurements within the central region of the cluster, obtained with the laser guide star adaptive optics system at Keck Observatory over a 3 year time baseline (2006-2009). This uniform dataset results in proper motion measurements that are improved by a factor ~5 over previous measurements from heterogeneous instruments, yielding internal velocity dispersion estimates 0.15 +/- 0.01 mas/yr, which corresponds to 5.4 +/- 0.4 km/s at a distance of 8.4 kpc. Projecting a simple model for the cluster onto the sky to compare with our proper motion dataset, in conjunction with surface density data, we estimate the total present-day mass of the cluster to be 15,000 (+7400 -6000) Solar masses. The mass in stars observed within a cylinder of radius R=0.4 pc is found to be 9000 (+4000 -3500) Solar Masses at formal 3-sigma confidence. This mass measurement is free from assumptions about the mass function of the cluster, and thus may be used to check mass estimates from photometry and simulation. When we conduct this check, we find that the present-day mass function of the Arches cluster is likely either top-heavy or truncated at low-mass, or both. Collateral benefits of our data and analysis include: 1. cluster membership probabilities, which may be used to extract a clean cluster sample for future photometric work; 2. a refined estimate of the bulk motion of the Arches cluster with respect to the field, which we find to be 172 +/- 15 km/s, which is slightly slower than suggested by previous VLT-Keck measurements; and 3. a velocity dispersion estimate for the field itself, which is likely dominated by the inner galactic bulge and the nuclear disk.
description: 73 pages, 28 figures, 12 tables, ApJ accepted
Beyond Pareto Analysis: A Decision Support Model for the Prioritization of Deviations with Natural Language Processing
Creators: name: Wang, Yuxi
name: Longard, Lukas
name: Hertle, Christian
name: Metternich, Joachim
Publisher: name: Hannover : publish-Ing.
Year: 2023
Subjects: subject: Konferenzschrift
subject: Systematic problem-solving (SPS)
subject: Deviation Management
subject: Natural Language Processing (NLP)
subject: Shop Floor Management
subject: Production and Manufacturing
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: In the manufacturing domain, the systematic problem-solving (SPS) process is essential to eliminate the root causes of deviations from expected performance. The major goal of SPS is to prevent the recurrence of known deviations. However, due to time and resource limitations, the deviations that occur on the shop floor should be prioritized before applying SPS. Therefore, a method to support the decision-making process for prioritization of deviations is required. Traditional methods, such as the Pareto analysis, are widely accepted and applied for easy use. But their performance is no more sufficient for the production environment with large fluctuations nowadays. Therefore, this paper proposes a decision support model - the error score - to prioritize deviations on the shop floor. The error score is calculated based on the process data as well as textual data found in the deviation documentation. As the quality of textual data in the deviation documentation has great effects on the performance of the model, Natural Language Processing (NLP) methods are developed to pre-process the unstructured text. To validate the model, it is applied to a real-world use case in the automotive industry to demonstrate and evaluate the performance. The study shows that the proposed model can effectively support the decision-making process on the shop floor and is superior to traditional methods.
On the 3-torsion Part of the Homology of the Chessboard Complex
Creators: name: Jonsson, Jakob
Publisher: name: arXiv
Year: 2012
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 55U10, 05E25

description: Let $1 \le m \le n$. We prove various results about the chessboard complex $M_{m,n}$, which is the simplicial complex of matchings in the complete bipartite graph $K_{m,n}$. First, we demonstrate that there is nonvanishing 3-torsion in $H_d(M_{m,n};Z)$ whenever $\frac{m+n-4}{3} \le d \le m-4$ and whenever $6 \le m < n$ and $d=m-3$. Combining this result with theorems due to Friedman and Hanlon and to Shareshian and Wachs, we characterize all triples $(m,n,d)$ satisfying $H_{d}(M_{m,n};Z) \neq 0$. Second, for each $k \ge 0$, we show that there is a polynomial $f_k(a,b)$ of degree 3k such that the dimension of $H_{k+a+2b-2}(M_{k+a+3b-1,k+2a+3b-1};Z_3)$, viewed as a vector space over $Z_3$, is at most $f_k(a,b)$ for all $a \ge 0$ and $b \ge k+2$. Third, we give a computer-free proof that $H_2(M_{5,5};Z) \cong Z_3$. Several proofs are based on a new long exact sequence relating the homology of a certain subcomplex of $M_{m,n}$ to the homology of $M_{m-2,n-1}$ and $M_{m-2,n-3}$.
description: 21 pages
SEAL: Capability-Based Access Control for Data-Analytic Scenarios
Creators: name: Rasifard, Hamed
name: Gopinath, Rahul
name: Backes, Michael
name: Nemati, Hamed
Publisher: name: CISPA
Year: 2023

description: Data science is the basis for various disciplines in the Big-Data era. Due to the high volume, velocity, and variety of big data, data owners often store their data in data servers. Past few years, many computation techniques have emerged to protect the security and privacy of such shared data while enabling analysis thereon. Hence, access-control systems must provide a fine-grained, multi-layer mechanism to protect data. However, the existing systems and frameworks fail to satisfy all these requirements and resolve the trust issue between data owners and analysts. In this paper, we propose SEAL as a framework to protect the security and privacy of shared data. SEAL enables computations on shared data while they remain under the complete control of data owners through pre-defined policies. Our framework employs the capability-object model to define flexible access policies. SEAL's access-control system supports delegating and revoking access privileges and other access-control customizations. In addition, SEAL can assign security labels to privacy-sensitive data and track them to enable data owners to define where and when a data analyst can access their data. We demonstrate the practicability of our approach by presenting a prototype implementation of SEAL. Furthermore, we display the flexibility of our framework by implementing multiple data-analytic scenarios, which cover different applications.
Synthesis and characterization of photochromic platinum-coordinated dithienylethenes
Creators: name: Roberts, Matthew
Publisher: name: University of British Columbia
Year: 2011

description: The syntheses and characterization of photochromic platinum-coordinated dithienylethenes (DTEs) are reported. Platinum acetylide complexes were investigated as potentially useful chromphores to integrate with photoresponsive DTEs. Acetylides were observed to be successful at promoting strong electronic interaction between the Pt atom and the DTE’s thienyl scaffold. As a result of platinum’s large spin-orbit coupling, these metal complexes exhibit a high propensity for generating excited states with triplet character upon photoexcitation. Consequently, platinum acetylide complexes were found to be effective sensitizers for population of DTE-localized triplet states via energy transfer between the two chromophores. Platinum terpyridine complexes were initially targeted because they exhibit long-lived excited states, whose lifetime could be potentially modulated by photoswitching of the appended DTE. In fact, selective irradiation of the Pt complex with visible light resulted in energy transfer from a metal-based excited state to the DTE chromophore, in either the ring-open or ring-closed state. The triplet excited state of the ring-open DTE was observed to be photoactive and underwent cyclization to the ring-closed form. The effect of the alkynyl linkage on energy transfer was studied by incorporating a longer, non-conjugated alkynyl linkage between the two chromophores. Lengthening the linker reduced excited-state interaction between the metal-based and DTE-localized states, but did not completely eliminate energy transfer. The high efficiency of metal-sensitized ring-closing in the Pt terpyridine system led to subsequent exploration of multifunctional systems, those containing more than one DTE. Symmetrical Pt(II)-bis(phosphine)bis(acetylide) complexes were used for the preparation of discrete model systems and extended oligomeric species. The Pt-acetylide linkage was successful in allowing photoswitching of multiple adjacent DTE chromophores while maintaining a conjugated pathway between DTE units. Optical and electrochemical characterization supported that adjacent DTEs are capable of electronic communication through the Pt center. Extended electronic delocalization observed when multiple adjacent DTEs are ring-closed makes this system suitable for applications utilizing π-conjugated materials.
Fourier Response of a Memristor: Generation of High Harmonics with Increasing Weights
Creators: name: Joglekar, Yogesh N.
name: Meijome, Natalia
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate the Fourier transform of the current through a memristor when the applied-voltage frequency is smaller than the characteristic memristor frequency, and the memristor shows hysteresis in the current-voltage plane. We find that when the hysteresis curve is "smooth", the current Fourier transform has weights at odd and even harmonics that decay rapidly and monotonically with the order of the harmonic; when the hysteresis curve is "sharp", the Fourier transform of the current is significantly broader, with non-monotonic weights at high harmonics. We present a simple model which shows that this qualitative change in the Fourier spectrum is solely driven by the saturation of memristance during a voltage cycle, and not independently by various system parameters such as applied or memristor frequencies, and the non-linear dopant drift.
description: 5 pages, 3 figures
Analytical approximations for low frequency band gaps in periodic arrays of elastic shells
Creators: name: Krynkin, Anton
name: Umnova, Olga
name: Taherzadeh, Shahram
name: Attenborough, Keith
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: This paper presents and compares three analytical methods for calculating low frequency band gap boundaries in doubly periodic arrays of resonating thin elastic shells. It is shown that both lattice sum expansions in the vicinity of its poles and self consistent scheme could be used to predict boundaries of low-frequency band gaps due to axysimmetric (n=0) and dipolar (n=1) shell resonances. The accuracy of the former method is limited to low filling fraction arrays, however the application of the matched asymptotic expansions could significantly improve approximations of the upper band gap boundary due to axysimmetric resonance. The self-consistent scheme is shown to be very robust and gives reliable results even for dense arrays with filling fraction higher than 40%. The results are used to predict the dependence of the position and width of the low frequency band gap on the properties of shells and their periodic arrays.
Cyber-Physical-Systems for Fluid Manufacturing Systems
Creators: name: Bozkurt, Ali
name: Fries, Christian
name: Tasci, Timur
name: Leberle, Urs
name: Kessler, Daniel
name: Joos, Markus
name: Hagg, Manuel
name: Neuschwander, Bernd
name: Hinderer, Moritz
Publisher: name: Hannover : publish-Ing.
Year: 2023
Subjects: subject: Konferenzschrift
subject: Cyber-physical Systems
subject: Digital Twin
subject: Material Flow Control
subject: Human-centered Production
subject: Automotive
subject: Fluid Manufacturing Systems
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: Increased volatility continues to challenge the automotive manufacturer's production performance. More than a century after the start of mass production, changeable production systems that allow the flexibility for the economic mass production of customized products have arisen. Limitations on established production systems are driving the development of changeable production systems like the Fluid Manufacturing System (FLMS). In an FLMS, the individual production modules are mobile and consist of Cyber-Physical Systems (CPS) which can be combined ad-hoc to adapt to changing requirements. By connecting different CPS - e.g., Autonomous Mobile Robots (AMR) or smart load carriers - adaptable and flexible production will be achieved. This paper presents the first real-world initiation of an FLMS with the design and development of CPS and digital twins for production and logistics at the ARENA2036 research campus.
Development of Phosphonate Monoester-Based Coordination Frameworks
Creators: name: Gelfand, Benjamin
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Materials Science

description: This thesis emphasizes the development and gas sorption properties of metal-phosphonate monoester compounds. The first chapter discusses hydrolytic stability in metal-organic frameworks, with a focus on the types of hydrolytic exposure and assessing stability. The next four chapters focus on the synthesis and characterization of seven new coordination compounds. The first three compounds (2-4) are compared and contrasted to a pillared-layered material consisting of barium and a linear diphosphonate (1); 2 is based on a planar triphosphonate analogue, 3 is based on a linear diphosphonate bis(monoester), and 4 is based on a planar triphosphonate tris(monoester). Though none of these materials have any function, comparisons of 1-4 has allowed several structural trends to be determined, notably that both the change from diphosphonate to triphosphonate and from phosphonate to phosphonate monoester result in the building units in 1 being truncated. 5 is based on the same linear ditopic phosphonate monoester as 3 but with copper(II) and is insoluble and stable in water, a feature not often seen with similar building units. 6 was synthesized based on the stability and building unit found in 5 but with the planar tritopic phosphonate monoester used in 4. 6 is a permanently porous material with a surface area exceeding 300 m^2/g. Though the same level of stability is not found in 6 as in 5, 6 was found to retain its crystallinity and porosity even in steam-like conditions. In an attempt to increase the porosity of 6, a longer linker was synthesized and used to make 7 and 8. 8 was found to be highly porous (>1000 m^2/g) and it was also discovered that one of the esters in 8 can be systematically hydrolyzed in situ in order to increase the materials affinity for CO2. Furthermore, experimental results and simulations for 8 conclude that the removal of these esters is randomly distributed in the framework, rather than being clustered. Though 7 is non-porous and no function has been found, it is made from nearly identical building units to 8, allowing for potential synthetic factors to be considered and discussed.
Investigating the Cosmic-Ray Ionization Rate in the Galactic Diffuse Interstellar Medium through Observations of H3+
Creators: name: Indriolo, Nick
name: McCall, Benjamin J.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Observations of H3+ in the Galactic diffuse interstellar medium (ISM) have led to various surprising results, including the conclusion that the cosmic-ray ionization rate (zeta_2) is about 1 order of magnitude larger than previously thought. The present survey expands the sample of diffuse cloud sight lines with H3+ observations to 50, with detections in 21 of those. Ionization rates inferred from these observations are in the range (1.7+-1.3)x10^-16 s^-1
description: 48 pages, 19 figures, 4 tables, accepted for publication in ApJ
Why I Can't Authenticate --- Understanding the Low Adoption of Authentication Ceremonies with Autoethnography
Creators: name: Fassl, Matthias
name: Krombholz, Katharina
Publisher: name: CISPA
Year: 2023

description: Authentication ceremonies detect and mitigate Man-in-the-Middle (MitM) attacks on end-to-end encrypted messengers, such as Signal, WhatsApp, or Threema. However, prior work found that adoption remains low as non-expert users have difficulties using them correctly. Anecdotal evidence suggests that security researchers also have trouble authenticating others. Since their issues are probably unrelated to user comprehension or usability, the root causes may lie deeper. This work explores these root causes using autoethnography. The first author kept a five-month research diary of their experience with authentication ceremonies. The results uncover points of failure while planning and conducting authentication ceremonies. They include cognitive load, forgetfulness, social awkwardness, and explanations required by a communication partner. Additionally, this work identifies and discusses how sociocultural aspects affect authentication ceremonies. Lastly, this work discusses a design approach for cooperative security that employs cultural transcoding to improve sociocultural aspects of security by design.
Synthesis of Artificial Coating Images and Parameter Data Sets in Electrode Manufacturing
Creators: name: Kampker, Achim
name: Heimes, Heiner Hans
name: Dorn, Benjamin
name: Clever, Henning
name: Drescher, Marcel
name: Ludwigs, Robert
Publisher: name: Hannover : publish-Ing.
Year: 2023
Subjects: subject: Konferenzschrift
subject: Machine Learning
subject: Generative Adversarial Networks
subject: Data Synthesis
subject: Electrode Manufacturing
subject: Battery Cell Production
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: Driven by continuous cost pressure and increasing market requirements, the optimisation of the lithium-ion battery production is focus of attention. In order to save time and costs, machine learning (ML) represent a promising tool. ML methods are able to analyse highly complex correlations and abstract data sets. But a considerable amount of training data is needed. Since data is not always available to the required extent, approaches for synthesising artificial data were investigated. In this study, the quality and corresponding measurement parameters in electrode production were assessed and selected. Based on this selection, coating trials have been conducted and the corresponding data set collected. The data set forms the basis for synthesis of artificial coating images and parameters. The selection and design of the synthesis models was divided into two sub-steps. First, the synthesis of artificial coating images was investigated. This was followed by the consideration of a procedure for the synthesis of structured data sets. A promising method for data synthesis of (coating) images are Generative Adversarial Networks (GAN). The basic idea of GANs is to oppose two models: a discriminator and a generator. The generator generates artificial data samples that match the input of the training dataset. Afterwards those data samples (both input and artificial data) are introduced to the discriminator. The discriminator's function is to identify whether the data presented originates from the training dataset or whether it is a counterfeit (artificial data) of the generator. The requirements for the synthesis of tabular data sets correspond in principle to those for a multivariate regression analysis. The combination of the models resulted in a method that allows the prediction of the corresponding measured quality values for arbitrarily selected process parameters, as well as the visualisation of the associated coating result in the form of an artificial image.
The vanishing of L2 harmonic one-forms on based path spaces
Creators: name: Elworthy, K. D.
name: Yang, Y.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 58J65, 60H07, 58A12, 58A14

description: We prove the triviality of the first L2 cohomology class of based path spaces of Riemannian manifolds furnished with Brownian motion measure, and the consequent vanishing of L2 harmonic one-forms. We give explicit formulae for closed and co-closed one-forms expressed as differentials of functions and co-differentials of L2 two-forms, respectively; these are considered as extended Clark-Ocone formulae. A feature of the proof is the use of the temporal structure of path spaces to relate a rough exterior derivative operator on one-forms to the exterior differentiation operator used to construct the de Rham complex and the self-adjoint Laplacian on L2 one-forms. This Laplacian is shown to have a spectral gap.
Different Researchers, Different Results? Analyzing the Influence of Researcher Experience and Data Type During Qualitative Analysis of an Interview and Survey Study on Security Advice
Creators: name: Ortloff, Anna-Marie
name: Fassl, Matthias
name: Ponticello, Alexander
name: Martius, Florin
name: Mertens, Anna
name: Krombholz, Katharina
name: Smith, Matthew
Publisher: name: CISPA
Year: 2023

description: When conducting qualitative research it is necessary to decide how many researchers should be involved in coding the data: Is one enough or are more coders beneficial? To offer empirical evidence for this question, we designed a series of studies investigating qualitative coding. We replicated and extended a usable security and privacy study by Ion et al. to gather both simple survey data and complex interview data. We had a total of 65 students and seven researchers analyze different parts of this data. We analyzed the codebook creation process, similarity of outcomes, inter-rater reliability, and compared the student to the researcher outcomes. We also surveyed five years of SOUPS-PC members about their views on coding. The reviewers view on coding practices for complex and simple data are almost identical. However, our results suggest that the coding process can be different for the two types of data, with complex data benefiting more from interaction between coders.
Categorizing Challenges And Potentials Of Digital Industrial Platforms
Creators: name: Eichholz, Jonas
name: Baumeister, Michael
name: Kreyenborg, Alexander
name: Hefft, Daniel
name: Große, Nick
name: Henke, Michael
Publisher: name: Hannover : publish-Ing.
Year: 2023
Subjects: subject: Konferenzschrift
subject: Platform
subject: Industrial Service
subject: B2B
subject: Literature Review
subject: Expert Workshop
subject: Category System
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: In complex supply chains, digital platforms play an emerging role as an infrastructure for network-based collaboration of industrial companies to stay competitive. Participating in a platform business offers a range of new potentials, while also introducing new challenges. Awareness of these is crucial for both users and providers to make informed decisions. Thus, this paper provides an overview about typical challenges and potentials from the perspective of potential or actual digital industrial platform users to support decision making processes. Against that backdrop, a descriptive study is conducted in the field of industrial service platforms motivated from two sides. Expert workshops are held to examine the practical opportunities and hurdles. The findings are then compared to those identified in literature. Then, the results are organized into a category system that highlights the key challenges and potentials for users as well as providers of digital industrial platforms.