Time filter

Source Type

Abdo H.,Free University of Berlin | Dimitrov D.,Hochschule fur Technik und Wirtschaft Berlin | Gao W.,Yunnan Normal University
Canadian Journal of Chemistry | Year: 2017

Measures of the irregularity of chemical graphs could be helpful for QSAR/QSPR studies and for the descriptive purposes of biological and chemical properties such as melting and boiling points, toxicity, and resistance. Here, we consider the following four established irregularity measures: The irregularity index by Albertson, the total irregularity, the variance of vertex degrees, and the Collatz-Sinogowitz index. Through the means of graph structural analysis and derivation, we study the above-mentioned irregularity measures of several chemical molecular graphs that frequently appear in chemical, medical, and material engineering, as well as the nanotubes: TUC4C8(S), TUC4C8(R), zigzag TUHC6, TUC4, Armchair TUVC6, then dendrimers Tk,d, and the circumcoronene series of benzenoid Hk. In addition, the irregularities of Mycielski's constructions of cycle and path graphs are analyzed.


Magnasco A.,Hochschule fur Technik und Wirtschaft Berlin | Kirchhoff H.,TU Berlin | Chowdhury S.,United International University Dhanmondi | Groh S.,ME SOLshare Ltd.
Energy Procedia | Year: 2016

In the context of the rural electrification challenge, sharing-based nanogrids represent an innovative approach for affordable and sustainable electricity. The peer-to-peer topology of these nanogrids is targeted at organic growth and thus requires real time monitoring and optimization. A data analysis tool has been developed, aiming at achieving an efficient power flow and real time optimization of generation, storage, load and distribution capacities. This paper elaborates the core algorithms of the network topology optimization and provides first results based on data from a pilot nanogrid in Bangladesh. © 2016 The Authors.


Herm S.,Hochschule fur Technik und Wirtschaft Berlin | Moller J.,Free University of Berlin
Psychology and Marketing | Year: 2014

Distinctive product design is a cornerstone of sustainable branding. Ideally, consumers will be able to identify brands by product design without seeing any logos. Once companies have established strong associations between product designs and brands in consumers' minds, they seek protection against imitation as well as consistency in product lines. This research discusses methods for measuring consumers' abilities to identify brands by product design. Study 1 shows that brand identification depends on the evaluation mode that the identification task evokes. Compared to a task that presents products side by side (comparative mode), participants are more likely to confuse copycats with an original design when they see only one product (noncomparative mode). Study 2 replicates findings of Study 1, demonstrating some robustness of effects across three countries (United States, Spain, Germany) and across three different product categories (beer, smartphones, cars). Study 2 further investigates how familiarity with the product influences brand identification. Although consumers with high (compared to low) familiarity are more likely to accurately identify an original product in a noncomparative evaluation mode, they are also more likely to confuse a copycat with the original product in this mode. Overall, this research extends knowledge about brand identification by product design and provides information brand managers may need for legal decisions in trademark or design patent cases. This research also provides information for brand managers making decisions regarding new product development, for example, product line extensions. © 2014 Wiley Periodicals, Inc.


Al-Labady N.,Istanbul University | Ozdalgic B.,Istanbul University | Er A.,Istanbul University | Guzelcimen F.,Istanbul University | And 6 more authors.
Astrophysical Journal, Supplement Series | Year: 2017

The Fourier Transform spectra of a Holmium hollow cathode discharge lamp have been investigated in the UV spectral range from 25,000 up to 31,530 cm-1 (317 to 400 nm). Two Ho spectra have been measured with neon and argon as buffer gases. Based on the intensity ratios from these two spectra, a distinction was made between atomic and ionic lines (ionic lines are discussed in an accompanying paper). Using the known Ho i energy levels, 71 lines could be classified as transitions of atomic Ho, 34 of which have not been published previously. Another 32 lines, which could not be classified, are listed in the literature and assigned as atomic Ho. An additional 370 spectral lines have been assigned to atomic Ho based on the signal-to-noise ratio in the two spectra measured under different discharge conditions, namely with buffer gases argon and neon, respectively. These 370 lines have not been previously listed in the literature. © 2017. The American Astronomical Society. All rights reserved..


Guzelcimen F.,Istanbul University | Basar G.,Istanbul University | Tamanis M.,University of Latvia | Kruzins A.,University of Latvia | And 3 more authors.
Astrophysical Journal, Supplement Series | Year: 2013

A high-resolution spectrum of lanthanum has been recorded by a Fourier Transform spectrometer in the wavelength range from 833 nm to 1666 nm (6000 cm-1 to 12,000 cm-1) using as light source a hollow cathode lamp operated with argon as the discharge carrier gas. In total, 2386 spectral lines were detected in this region, of which 555 lines could be classified as La I transitions and 10 lines as La II transitions. All La II transitions and 534 of these La I transitions were classified for the first time, and 6 of the La II transitions and 433 of the classified La I transitions appear to be new lines, which could not be found in the literature. The corresponding energy level data of classified lines are given. Additionally, 430 lines are assigned as Ar I lines and 394 as Ar II lines, of which 179 and 77, respectively, were classified for the first time. All 77 classified Ar II transitions as well as 159 of the classified Ar I transitions are new lines. Furthermore, the wavenumbers of 997 unclassified spectral lines were determined, 235 of which could be assigned as La lines, because of their hyperfine pattern. The remaining 762 lines may be either unclassified Ar lines or unresolved and unclassified La lines with only one symmetrical peak with an FWHM in the same order of magnitude as the Ar lines. The accuracy of the wavenumber for the classified lines with signal-to-noise-ratio higher than four is better than 0.006 cm-1 which corresponds to an accuracy of 0.0004 nm at 830 nm and 0.0017 nm at 1660 nm, respectively. © 2013. The American Astronomical Society. All rights reserved..


Dembczynski J.,Poznan University of Technology | Elantkowska M.,Poznan University of Technology | Ruczkowski J.,Poznan University of Technology | Ozturk I.K.,Istanbul University | And 4 more authors.
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2015

In this work a parametric study of the fine and hyperfine structure (hfs) for the even parity configurations of atomic niobium (Nb I) is presented. A large amount of new experimental data, published during the last decade, have been considered for the fine and hfs analysis. A multi-configuration fit of 14 configurations have been performed by taking into account second-order of perturbation theory including the effects of closed shell-open shell excitations. Predicted values of level energies as well as magnetic dipole and electric quadrupole hfs constants of A and B are listed, if no experimental values are available. © 2015 IOP Publishing Ltd.


Ozturk I.K.,Istanbul University | Basar G.,Istanbul University | Er A.,Istanbul University | Guzelcimen F.,Istanbul University | And 2 more authors.
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2015

Laser-induced fluorescence spectroscopy was applied in order to find new energy levels of the niobium atom. A continuous wave tuneable titanium-sapphire laser in the wavelength range from 750 to 865 nm and a hollow-cathode lamp were used. We discovered four energy levels of even parity, three lying levels below 19 000 cm-1 and one at much higher energy. Additionally hyperfine structure data of six levels of odd parity were determined. © 2015 IOP Publishing Ltd.


Guzelcimen F.,Istanbul University | Yapici B.,Istanbul University | Demir G.,Istanbul University | Er A.,Istanbul University | And 7 more authors.
Astrophysical Journal, Supplement Series | Year: 2014

High-resolution Fourier transform spectra of a vanadium-argon plasma have been recorded in the wavelength range of 365-670 nm (15,000-27,400 cm-1). Optical bandpass filters were used in the experimental setup to enhance the sensitivity of the Fourier transform spectrometer. In total, 138 atomic vanadium spectral lines showing resolved or partially resolved hyperfine structure have been analyzed to determine the magnetic dipole hyperfine structure constants A of the involved energy levels. One of the investigated lines has not been previously classified. As a result, the magnetic dipole hyperfine structure constants A for 90 energy levels are presented: 35 of them belong to the configuration 3d 34s4p and 55 to the configuration 3d 44p. Of these 90 constants, 67 have been determined for the first time, with 23 corresponding to the configuration 3d 34s4p and 44 to 3d 44p. © 2014. The American Astronomical Society. All rights reserved..


Kasper R.,RWTH Aachen | Pieplow K.,Hochschule fur Technik und Wirtschaft Berlin
Stahlbau | Year: 2011

The implementation of the first two parts of the design and construction regulations for glass in structural engineering by the responsible building authorities is imminent. For the user this implies that for glass components soon much more time consuming structural design calculations according to the partial safety concept have to be carried out. Especially for multi-layered insulating float glass this leads to an increasing effort, because the loads are assigned to different duration which are taken into account on the resistance side in the form of a load duration dependent tensile strength. This structural design calculation approach satisfies the material properties of glass but also increases the computational effort. By means of examples the major changes in the new design and construction regulations are illustrated. © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.


Classen I.,Hochschule fur Technik und Wirtschaft Berlin
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

This paper introduces a new language for analysis of multidimensional data. Its design is discussed and a reference to a formal semantics is given. © 2010 Springer-Verlag.

Loading Hochschule fur Technik und Wirtschaft Berlin collaborators
Loading Hochschule fur Technik und Wirtschaft Berlin collaborators