Coeurjolly Jean-Francois, Ba Ismaïla, Choiruddin Achmad
Point processes are stochastic models generating interacting points or events in time and/or space. Among characteristics of these models, first-order intensity and conditional intensity functions are often considered. We focus on inhomogeneous parametric forms of these functions assumed to depend on a certain number of spatial covariates. When this number of covariates is large, we are faced with a high-dimensional problem. This paper provides an overview of these questions and existing solutions based on regularizations.
Nanang Alamsyah, Mohammad Rachman Waluyo, Muthia Zenzy Ariani
The incompatibility of the quality of the goods sent and the delay in delivery resulted in the company suffering losses and creating an unfavourable image in the company consumer's eyes. Both factors can be caused by error in the supplier selection process of raw material. The purpose of this research is to select the best supplier in the procurement process at the largest paper-producing company in Indonesia, which begins with determining the criteria that influence the selection of suppliers. The Analytical Hierarchy Process and the Best Worst Method were used in this study. Based on 4 personnel in the procurement department, 8 criteria were found for selecting suppliers with 3 alternative suppliers. The selected criteria are: Certificate Quality, Defect Rate, Offer Price, Discounts, Delivery Time, Order Fulfilment, Power Respond, and Work History. The offer price is the most important variable with a weight of 29.3%. Supplier A was selected with a score of 66.78%, while Supplier C became the second alternative priority and Supplier B became the third alternative priority.
In this paper, we study lump solutions and rogue wave solutions for three (1+1)-dimensional nonlinear dynamic systems. By applying the Hirota direct method, lump and rogue wave solutions are presented with the aid of symbolic computations. The solutions are expressed in terms of a set of restricted parameters with necessary and sufficient conditions that guarantee their existence.
Based on the asymmetric copula function, this paper analyzes the static and dynamic correlation between Shanghai Composite Index and Shenzhen Composite Index. Through the static analysis, it is found that the asymmetric copula function is better than Gumbel Copula in describing the distribution characteristics of the top tail dependence between the Shanghai Composite Index and the Shenzhen Composite Index, and the copula correlation coefficient definition based on the asymmetric copula function can well describe the asymmetric dependence between variables. In the time-varying analysis, the paper improves the traditional dynamic evolution equation of the tail-dependence coefficient. Through empirical analysis, the result shows that the improved dynamic evolution equation can better reflect the dynamic evolution process of the tail-dependence coefficient.
Nadiyah Mufidah, Tika Dwi Nopriyanti, Yunika Lestaria Ningsih
The purpose of this study is to evaluate the feasibility of vector e-modules based on project-based learning for students in class X SMA. This study is a continuation of development research using a 4D model (define, design, development, and dissemination). The feasibility of the e-module is assessed in the development section, which includes three trial stages: one-to-one, small group, and field test. 35 students from SMA Negeri 15 Palembang participated in this study. Questionnaires, interviews, and written tests were used to collect data. The results of the questionnaire and written test were analyzed quantitatively, while the data from interviews were analyzed qualitatively. Based on the results of the one-to-one stage, it is clear that the e-module has an interesting appearance, is simple to use, and includes videos to help students understand the material. The e-module has a practicality level of 77,4 % in the small-group stage and 79,4 percent in the field test stage. This data is backed up by students' ability to solve vector material problems in the e-module, which is 78.4 percent at the field test stage. Based on the data analysis results, it is possible to conclude that the e-module vector based on project-based learning is practically used in learning with a moderate level of practicality.
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Keywords: E-Module, Project Based Learning, Vector
José Manuel Matos, Alexandra Sofia Cunha Rodrigues
Em janeiro de 1967 começa a ser publicada a Folha Informativa dos Professores do 1.º Grupo (E. T. P.) que é o primeiro periódico português consagrado exclusivamente à educação matemática no ensino técnico. A “Folha” destinava-se a acompanhar a experiência de introdução da Matemática Moderna nesse ramo de ensino apoiando os professores responsáveis pela lecionação das disciplinas relacionadas com a matemática, e publica 66 números e 9 suplementos até março de 1972. Este artigo estuda a importância assumida por esta revista, na comunidade de professores de matemática, para promover a partilha de experiências e melhorar o ensino da disciplina.
Special aspects of education, Applied mathematics. Quantitative methods
Wind energy is renewable energy extrapolated from the wind that has the potential to revolutionize our power supply in the near future as fossil fuels become outdated. Wind turbines capture the energy as the wind spins the blades of the turbine, transforming wind energy into mechanical energy and then into electrical energy through a generator. One of the techniques utilized to understand wind energy is to manipulate various variables in the formula for wind power. These variables such as the power coefficient, wind velocity, number and length of blades are explored to find its optimal value. The variable of turbine efficiency is explored by deriving Betz limit from the known physics formulas, in order to understand one of the limitations of the wind energy formula. It can be deduced that turbine design is also valuable for the efficiency of wind turbines. This is where the length and the number of blades are explored through the tip speed ratio in order to understand how to achieve maximum efficiency.
We extend the theory of Barles Jakobsen [3] for a class of almost monotone schemes to solve stationary Hamilton Jacobi Bellman equations. We show that the monotonicity of the schemes can be relaxed still leading to the convergence to the viscosity solution of the equation even if the discrete problem can only be solved with some error. We give some examples of such numerical schemes and show that the bounds obtained by the framework developed are not tight. At last we test the schemes.
Mikhail U. Nikabadze, Armine R. Ulukhanyan, Tamar Moseshvili
et al.
Proceeding from three-dimensional formulations of initial boundary value problems of the three-dimensional linear micropolar theory of thermoelasticity, similar formulations of initial boundary value problems for the theory of multilayer thermoelastic thin bodies are obtained. The initial boundary value problems for thin bodies are also obtained in the moments with respect to systems of orthogonal polynomials. We consider some particular cases of formulations of initial boundary value problems. In particular, the statements of the initial-boundary value problems of the micropolar theory of <i>K</i>-layer thin prismatic bodies are considered. From here, we can easily get the statements of the initial-boundary value problems for the five-layer thin prismatic bodies.
This paper presents an improved frequency estimation algorithm based on the interpolated discrete Fourier transform. High-accurate frequency estimation can be achieved by taking the geometric mean of two independent estimates, which are derived from the real parts of the two largest spectral bins and the imaginary parts, respectively. In situations where only a small number of sine wave cycles are observed, the ability of the algorithm to cancel interference from image frequency components results in improvements in accuracy. The residual errors of the proposed algorithm have been theoretically analyzed with maximum side-lobe decaying windows, since the windows have simple and uniform analytical expression of interpolation algorithm. The performance of the proposed algorithm was investigated using both Hanning and three-term maximum side-lobe decaying windows. A comparative analysis of systematic errors and noise sensitivity was performed between the new algorithm and traditional algorithms. Both the root mean squared error and the probability density of the errors were investigated under noisy conditions. Simulation results demonstrated that the new algorithm is not only highly resistant to interference from image components but is also resistant to the effects of random noise. The results presented in the paper are useful for identifying the best choice of algorithm in practical engineering applications.
Mariska Heemskerk, Johan van Leeuwaarden, Michel Mandjes
This paper studies the effect of an overdispersed arrival process on the performance of an infinite-server system. In our setup, a random environment is modeled by drawing an arrival rate Λ from a given distribution every Δ time units, yielding an i.i.d. sequence of arrival rates Λ<sub>1</sub>,Λ<sub>2</sub>,…. Applying a martingale central limit theorem, we obtain a functional central limit theorem for the scaled queue length process. We proceed to large deviations and derive the logarithmic asymptotics of the queue length's tail probabilities. As it turns out, in a rapidly changing environment (i.e., Δ is small relative to Λ) the overdispersion of the arrival process hardly affects system behavior, whereas in a slowly changing random environment it is fundamentally different; this general finding applies to both the central limit and the large deviations regime. We extend our results to the setting where each arrival creates a job in multiple infinite-server queues.
A interdisciplinaridade é um desafio que surge entre os professores que tentam criar elos entre disciplinas. Em relação à disciplina Matemática, não é tarefa fácil para professores associar os conteúdos escolares a temas do cotidiano de um modo geral, muito em virtude da formação inadequada. Neste artigo tem-se como objetivo discutir a Matemática como linguagem e possibilidades de interação com a Língua Portuguesa e a Filosofia. Para tanto, realizou-se uma investigação qualitativa bibliográfica, de cunho exploratório, por meio da análise comparativa dos diferentes significados atribuídos pelas três áreas em questão a determinados termos matemáticos, a saber: axioma, teorema, demonstração, arbitrário, e, ou, não, quantificação e implicação. Espera-se que os resultados contribuam para reforçar a importância da linguagem, do texto e do raciocínio lógico como possibilidades de interação entre Matemática, Língua Portuguesa e Filosofia, visando o desenvolvimento da literacia matemática por parte dos educandos.
Special aspects of education, Applied mathematics. Quantitative methods
Recent research in the field of investor preference has emphasised the need to go beyond just simply analyzing the first two moments of a portfolio return distribution used in a MV (mean-variance) paradigm. The suggestion is to observe an investor's utility function as an nth order Taylor approximation. In such terms, the assumption is that investors prefer greater values of odd and smaller values of even moments. In order to investigate the preferences of Croatian investment funds, an analysis of the moments of their return distribution is conducted. The sample contains data on monthly returns of 30 investment funds in Croatia for the period from January 1999 to May 2014. Using the theoretical utility functions (DARA, CARA, CRRA), we compare changes in their preferences when higher moments are included. Moreover, we investigate an extension of the CAPM model in order to find out whether including higher moments can explain better the relationship between the awards and risk premium, and whether we can apply these findings to estimate preferences of Croatian institutional investors. The results indicate that Croatian institutional investors do not seek compensation for bearing greater market risk.
Penting bagi guru untuk memilih pendekatan pembelajaran yang sesuai dengan kebutuhan belajar siswa. Pemilihan dan penggunaan pendekatan pembelajaran harus bisa mengarahkan siswa belajar lebih aktif sehingga dapat mengaplikasikannya dalam kehidupan sehari-hari.
Penelitian ini bertujuan untuk mendeskripsikan: (1) keefektifan pendekatan open-ended dan CTL ditinjau dari prestasi belajar; (2) keefektifan pendekatan open-ended dan CTL ditinjau dari sikap belajar; dan (3) perbedaan keefektifan pendekatan open-ended dan pendekatan CTL ditinjau dari prestasi dan sikap belajar matematika.
Penelitian ini merupakan penelitian eksperimen semu. Populasi penelitian mencakup seluruh siswa kelas VII SMPN 1 Sekampung yang terbagi dalam lima kelas sedangkan sampel penelitian terdiri dari dua kelas yang ditentukan secara acak. Teknik analisis data terdiri dari analisis deskriptif dan analisis inferensial yang meliputi: 1) one sample t-test yang digunakan untuk mendeskripsikan keefektifan pendekatan open-ended dan CTL pada masing-masing variabel; 2) analisis multivariat (MANOVA) yang digunakan untuk mengetahui ada tidaknya perbedaan keefektifan pendekatan open-ended dan CTL secara simultan pada kedua variabel dependen.
Hasil penelitian menunjukkan bahwa: 1) pendekatan open-ended dan CTL sama-sama efektif ditinjau dari prestasi belajar; 2) pendekatan open-ended dan CTL sama-sama efektif ditinjau dari sikap belajar; dan 3) tidak ada perbedaan keefektifan antara pendekatan open-ended dan CTL ditinjau dari prestasi dan sikap belajar matematika.
Kata kunci: Open-Ended, Contextual Teaching and Learning (CTL), prestasi belajar, sikap belajar.
The report presents an analysis of Big Data storage solutions in different directions. The purpose of this paper is to introduce the technology of Big Data storage, prospects of storage technologies, for example, the software DIRAC. The DIRAC is a software framework for distributed computing.
The report considers popular storage technologies and lists their limitations. The main problems are the storage of large data, the lack of quality in the processing, scalability, the lack of rapid availability, the lack of implementation of intelligent data retrieval.
Experimental computing tasks demand a wide range of requirements in terms of CPU usage, data access or memory consumption and unstable profile of resource use for a certain period. The DIRAC Data Management System (DMS), together with the DIRAC Storage Management System (SMS) provides the necessary functionality to execute and control all the activities related with data.
In this paper we consider statistical estimates of threshold and strength of percolation clusters on square lattices. The percolation threshold pc and the strength of percolation clusters P for a square lattice with (1,)-neighborhood depends not only on the lattice dimension, but also on the Minkowski exponent d. To estimate the strength of percolation clusters P proposed a new method of averaging the relative frequencies of the target subset of lattice sites. The implementation of this method is based on the SPSL package, released under GNU GPL-3 using the free programming language R.