Simple factor analysis of measured data

Kozar, Ivica,Kozar, Danila Lozzi,Malic, Neira Toric Techno-Press 2022 Coupled systems mechanics Vol.11 No.1

Quite often we have a lot of measurement data and would like to find some relation between them. One common task is to see whether some measured data or a curve of known shape fit into the cumulative measured data. The problem can be visualized since data could generally be presented as curves or planes in Cartesian coordinates where each curve could be represented as a vector. In most cases we have measured the cumulative 'curve', we know shapes of other 'curves' and would like to determine unknown coefficients that multiply the known shapes in order to match the measured cumulative 'curve'. This problem could be presented in more complex variants, e.g., a constant could be added, some missing (unknown) data vector could be added to the measured summary vector, and instead of constant factors we could have polynomials, etc. All of them could be solved with slightly extended version of the procedure presented in the sequel. Solution procedure could be devised by reformulating the problem as a measurement problem and applying the generalized inverse of the measurement matrix. Measurement problem often has some errors involved in the measurement data but the least squares method that is comprised in the formulation quite successfully addresses the problem. Numerical examples illustrate the solution procedure.

ON CONGRUENCES WITH THE TERMS OF THE SECOND ORDER SEQUENCES {U_kn} AND {V_kn}

KOPARAL, SIBEL,OMUR, Nese The Honam Mathematical Society 2018 호남수학학술지 Vol.40 No.3

In this paper, we consider the congruences involving harmonic numbers and the terms of the sequences {$U_{kn}$} and {$V_{kn}$}. For example, for an odd prime number p, $${\sum\limits_{i=1}^{p-1}}H_i{\frac{U_{k(i+m)}}{V^i_k}}{\equiv}{\frac{(-1)^kU_{k(m+1)}}{_pV^{p-1}_k}}(V^p_k-V_{kp})(mod\;p)$$, where $m{\in}{\mathbb{Z}}$ and $k{\in}{\mathbb{Z}}$ with $p{\nmid}V_k$.

Teaching and Research in International Law in Indonesia

Komar Kantaatmadja 대한국제법학회 1984 國際法學會論叢 Vol.29 No.2

Coupled experimental phase diagram study and thermodynamic optimization of the Li₂ O-MgO-SiO₂ system

Konar, Bikram,Kim, Dong-Geun,Jung, In-Ho Wiley (Blackwell Publishing) 2018 Journal of the American Ceramic Society Vol.101 No.4

<P>A coupled key phase diagram study and critical evaluation and optimization of all available experimental data of the Li2O-MgO-SiO2 system was performed to obtain a set of Gibbs energy functions to reproduce all the reliable phase equilibria and thermodynamic data. Differential scanning calorimetry measurements and equilibration/quenching experiments were performed in the Li2SiO3-MgO and Li4SiO4-Mg2SiO4 sections, respectively, using sealed Pt capsules to prevent the volatile loss of Li. According to the present experimental results, Li2MgSiO4 is the only compound present in the Li4SiO4-Mg2SiO4 isopleth, which shows a peritectic melting at 1465 +/- 6 degrees C (1738 +/- 6 K). The Modified Quasichemical Model, which considers short-range ordering in the melt, was employed to describe the thermodynamic properties of the liquid phase. The Li4SiO4-Li2MgSiO4 and Mg2SiO4-rich solid solutions were modeled using the Compound Energy Formalism.</P>

Trichomes and Regeneration by Direct Organogenesis of Medicinal Plant Dracocephalum kotschyi L. Using Shoot Tips (Lamiaceae)

Kosar, Moradi,Mahmoud, Otroshy 한국작물학회 2012 Journal of crop science and biotechnology Vol.15 No.3

The present study describes the procedure for micropropagation of Dracocephalum kotschyi L. using shoot tips from in vitro-germinated plants. The best response was observed for shoot tips on MS medium containing 5 mg 6-benzylaminopurine $L^{-1}$ and 0.2 mg 1-naphthaleneacetic $L^{-1}$ acid. Regeneration for other types of the explant hypocotyls and cotyledons did not show satisfactory results so that the explants did not develop into normal shoots and in turn developed into the calli after 12 days of culture. Histochemical analysis showed that only the shoot tip revealed a direct induction of more teratological protuberances that arise around the cut end of the explants. Elongation of shoot buds was obtained on MS medium containing 1 mg BAP $L^{-1}$ + 0.5 mg IBA $L^{-1}$. Regenerated shoots rooted best on the same medium of elongation. After hardening, the rooted plants were transferred to the greenhouse where they grew, matured, and flowered normally with a survival rate of 95%. We concluded that the present protocol can be efficiently used for mass propagation of Dracocephalum kotschyi.

Passive control of seismically excited structures by the liquid column vibration absorber

Konar, Tanmoy,Ghosh, Aparna Dey Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.5

The potential of the liquid column vibration absorber (LCVA) as a seismic vibration control device for structures has been explored in this paper. In this work, the structure has been modeled as a linear, viscously damped single-degree-of-freedom (SDOF) system. The governing differential equations of motion for the damper liquid and for the coupled structure-LCVA system have been derived from dynamic equilibrium. The nonlinear orifice damping in the LCVA has been linearized by a stochastic equivalent linearization technique. A transfer function formulation for the structure-LCVA system has been presented. The design parameters of the LCVA have been identified and by applying the transfer function formulation the optimum combination of these parameters has been determined to obtain the most efficient control performance of the LCVA in terms of the reduction in the root-mean-square (r.m.s.) displacement response of the structure. The study has been carried out for an example structure subjected to base input characterized by a white noise power spectral density function (PSDF). The sensitivity of the performance of the LCVA to the coefficient of head loss and to the tuning ratio have also been examined and compared with that of the liquid column damper (LCD). Finally, a simulation study has been carried out with a recorded accelerogram, to demonstrate the effectiveness of the LCVA.

Inverse model for pullout determination of steel fibers

Kozar, Ivica,Malic, Neira Toric,Rukavina, Tea Techno-Press 2018 Coupled systems mechanics Vol.7 No.2

Fiber-reinforced concrete (FRC) is a material with increasing application in civil engineering. Here it is assumed that the material consists of a great number of rather small fibers embedded into the concrete matrix. It would be advantageous to predict the mechanical properties of FRC using nondestructive testing; unfortunately, many testing methods for concrete are not applicable to FRC. In addition, design methods for FRC are either inaccurate or complicated. In three-point bending tests of FRC prisms, it has been observed that fiber reinforcement does not break but simply pulls out during specimen failure. Following that observation, this work is based on an assumption that the main components of a simple and rather accurate FRC model are mechanical properties of the concrete matrix and fiber pullout force. Properties of the concrete matrix could be determined from measurements on samples taken during concrete production, and fiber pullout force could be measured on samples with individual fibers embedded into concrete. However, there is no clear relationship between measurements on individual samples of concrete matrix with a single fiber and properties of the produced FRC. This work presents an inverse model for FRC that establishes a relation between parameters measured on individual material samples and properties of a structure made of the composite material. However, a deterministic relationship is clearly not possible since only a single beam specimen of 60 cm could easily contain over 100000 fibers. Our inverse model assumes that the probability density function of individual fiber properties is known, and that the global sample load-displacement curve is obtained from the experiment. Thus, each fiber is stochastically characterized and accordingly parameterized. A relationship between fiber parameters and global load-displacement response, the so-called forward model, is established. From the forward model, based on Levenberg-Marquardt procedure, the inverse model is formulated and successfully applied.

ON CONGRUENCES INVOLVING THE GENERALIZED CATALAN NUMBERS AND HARMONIC NUMBERS

Koparal, Sibel,Omur, Nese Korean Mathematical Society 2019 대한수학회보 Vol.56 No.3

In this paper, we prove some congruences involving the generalized Catalan numbers and harmonic numbers modulo $p^2$, one of which is $$\sum\limits_{k=1}^{p-1}k^2B_{p,k}B_{p,k-d}{\equiv}4(-1)^d\{{\frac{1}{3}}d(2d^2+1)(4pH_d-1)-p\({\frac{26}{9}}d^3+{\frac{4}{3}}d^2+{\frac{7}{9}}d+{\frac{1}{2}}\)\}\;(mod\;p^2)$$, where a prime number p > 3 and $1{\leq}d{\leq}p$.

Material model for load rate sensitivity

Kozar, Ivica,Ibrahimbegovic, Adnan,Rukavina, Tea Techno-Press 2018 Coupled systems mechanics Vol.7 No.2

This work presents a novel model for analysis of the loading rate influence onto structure response. The model is based on the principles of nonlinear system dynamics, i.e., consists of a system of nonlinear differential equations. In contrast to classical linearized models, this one comprises mass and loading as integral parts of the model. Application of the Kelvin and the Maxwell material models relates the novel formulation to the existing material formulations. All the analysis is performed on a proprietary computer program based on Wolfram Mathematica. This work can be considered as an extended proof of concept for the application of the nonlinear solid model in material response to dynamic loading.

Theoretical Principles Of Using Innovative Modern Technologies In Higher Education Institutions

Komar, Olha,Bazhenkov, Ievgen,Vnukova, Оlga,Kolomoiets, Halyna,Yanchyshyn, Anatolii,Polishchuk, Oksana International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.9

The article is assigned to a prelude to the joke of effective pedagogical technologies in professional education in the minds of її continuity. Analyzed the definitions "innovation", "technology", "pedagogical technology", "Innovation pedagogical technology". Blocks have been added, which are stored in innovation processes in the light. The significant role of innovation in education is stated. Presented warehouses pedagogical technologies: conceptual, conceptual-processual and professional. The purpose of introducing innovative technologies into the educational process of vocational education institutions has been clarified. The reasons for finding and implementing innovative pedagogical technologies in education are analyzed.