Мінімізація сумарного зваженого запізнення завдань із спільним директивним строком на паралельних приладах для випадку узгоджених ваг і тривалостей

We consider n tasks scheduling problem on m identical parallel machines by the criterion of minimizing the total weighted tardiness of tasks. All tasks arrive for processing at the same time. Weights and processing times are agreeable, that is, a greater weight of a task corre sponds to a shorter processing time. In addition, we have arbitrary start times of machines for tasks processing. The times may be less or greater than the due date or to coincide with it. The problem in this formulation is addressed for the first time. It can be used to provide planning and decision making in systems with a network representation of technological processes and limited resources. We give efficient PSC-algorithm with ( log ) complexity that includes the polynomial component and the approximation algorithm based on permutations of tasks. The polynomial component contains sufficient signs of optimality of the obtained solutions and allows to obtain an exact solution by polynomial subalgorithm. In the case when the sufficient signs of optimality do not fulfill, we obtain approximate solution with an estimate of deviation from the optimum for each individual problem instance of any practical dimension. We show that a schedule obtained as a result of the problem solving can be split into two schedules: the schedule on machines which start time is less than or equal to the due date, and the schedule on machines which start after the due date. Optimization is only done in the first schedule. The second schedule is optimal by construction. Statistical studies of the PSC-algorithm showed its high efficiency. We solved problems with dimensions up to 40,000 tasks and up to 30 machines. The average time to solve the problem by the algorithm using the most efficient types of permutations was 27.3 ms for this dimension. The average frequency of an optimal solution obtaining amounted to 90.3 %. The average deviation from an optimum was no more than 0.000251.Розглядається задача складання розкладів виконання n завдань на m ідентичних паралельних приладах за критерієм мінімізації сумарного зваженого запізнення завдань. Всі завдання надходять на обслуговування одночасно. Ваги і тривалості узгоджені, тобто завданню з меншою тривалістю відповідає більша вага. Додатково, задані довільні моменти початку роботи приладів на виконання завдань, які можуть бути як менше директивного строку, так і більше, або співпадати з ним. У такій постановці задача розв'язується вперше. Вона може використовуватися для забезпечення планування та прийняття рішень в системах з мережним представленням технологічних процесів та обмеженими ресурсами. Наведено ефективний ПДС-алгоритм її розв'язання із трудомісткістю ( log ), який включає поліноміальну складову з достатніми ознаками оптимальності одержуваних розв'язків, яка дозволяє отримувати точний розв'язок поліноміальним підалгоритмом. У разі невиконання достатніх ознак оптимальності ми отримуємо наближений розв'язок з оцінкою відхилення отриманого розв'язку від оптимального для кожної індивідуальної задачі будь-якої практичної розмірності. Показано, що розклад, отриманий в результаті розв'язання задачі, можна умовно розбити на два розклади – розклад на приладах, момент початку роботи яких менше або дорівнює директивному строку, та розклад на приладах, що починають роботу після директивного строку. Оптимізація виконується тільки у першому розкладі. Другий розклад оптимальний за побудовою. Статистичні дослідження ПДС-алгоритму показали його високу ефективність. Розв'язувались задачі з розмірністю до 40 000 завдань з числом приладів до 30. Середній час розв'язання задачі алгоритмом, що використовує найбільш ефективні типи перестановок, склав 27,3 мс при цій розмірності. Середня частота отримання оптимального розв'язку склала до 90,3 %. Середнє відхилення від оптимуму – не більш, ніж 0,000251

Nacionalismo de exportação: Portinari, identidade brasileira e os Estados Unidos (1935-1942)

Candido Portinari trazó una gloriosa trayectoria en Estados Unidos entre 1935 hasta 1942, marcada por obras emblemáticas elaboradas para este país: Café, los paneles del pabellón brasileño en la Feria Mundial de Nueva York y los murales en la Biblioteca del Congreso. Examinamos el carácter singular e experimental de esas representaciones de Brasil elaboradas para la América del Norte – casi todas patrocinadas por el Estado Nuevo – bien cómo su recepción por el público estadounidense. Esta investigación se fundamenta en fuentes primarias del periodo, especialmente correspondencias, memorandos institucionales, textos críticos y artículos de periódicos. Las obras analizadas son un breviario de los conceptos de brasilidad impulsados en los Estados Unidos por la pintura nacional a lo largo de la Política de Buena Vecindad y aclaran la promoción del Brasil ahí en este momento. Candido Portinari traveled a glorious trajectory in the United States between 1935 and 1942, during which he created emblematic artworks for the country: Coffee, the panels of the Brazilian pavilion at the New York World Fair and the murals at the Library of Congress. We examine the distinctive and experimental character of these pictorial representations of Brazil created for North America – almost all sponsored by the Estado Novo regime – as well as their reception by the American public. The main documental sources used are institutional memoranda, correspondence, critical texts, and newspaper articles from the 1930s and 1940s. The artworks analyzed present a breviary of the ideal of brasilidade fomented in the United States through Brazilian painting during the Good Neighbor Policy and clarify Brazil’s promotion in America in this period. Candido Portinari trilhou trajetória gloriosa nos Estados Unidos entre 1935 e 1942, marcada por obras emblemáticas elaboradas para este país: Café, os painéis do pavilhão brasileiro na Feira Mundial de Nova York e os murais da Biblioteca do Congresso. Examinamos o caráter único e experimental dessas representações de Brasil elaboradas por Portinari para a América do Norte – quase todas patrocinadas pelo Estado Novo –, bem como sua recepção pelo público estadunidense. Esta investigação fundamenta-se em fontes primárias do período, especialmente correspondências, memorandos institucionais, textos críticos e artigos de periódicos. As obras analisadas são um breviário dos conceitos de brasilidade fomentados nos Estados Unidos pela pintura nacional durante a Política da Boa Vizinhança e esclarecem a promoção do Brasil ali nesse período.

Sua excelência a "informalidade" : gestão de pequenos negócios num bairro periférico de Porto Alegre

Este trabalho buscou compreender as práticas administrativas dos empreendedores da Lomba do Pinheiro, um bairro periférico de Porto Alegre, RS. É uma pesquisa de caráter exploratório com enfoque qualitativo. Foram selecionados os pequenos negócios de maior longevidade para aplicação de um questionário modelo utilizado pelo SEBRAE, com o objetivo de identificar dimensões de excelência em gestão. Durante a coleta de dados, verificou-se a inadequação da ferramenta, o que levou a autora a repensar sua compreensão da realidade local. As dificuldades de compreensão e linguagem de parte dos entrevistados levaram ao ajuste da estratégia de coleta de dados, via anotações e questões complementares. Observou-se que a dimensão cultural é central à compreensão da administração naquele contexto, uma vez que elementos de ordem cultural se manifestavam nas práticas cotidianas dos empreendimentos. As conclusões apontam a distância entre modelos teóricos – nesse caso aqueles da chamada “excelência” – e realidade das práticas administrativas. Ao mesmo tempo, foi possível relacionar o modelo revelado inadequado a pressupostos culturais japoneses, muito diferentes daqueles do local em que a pesquisa foi realizada. Isto pode explicar, em parte, seu fracasso.The research aims to understand the administrative practices of entrepreneurs from Lomba do Pinheiro, a peripheral district of Porto Alegre, a city in southern Brazil. It is an exploratory research with a qualitative approach. Small businesses which last longer were selected to apply a standard questionnaire largely used by SEBRAE, in order to identify dimensions of excellence in management. During data collection, the inadequacy of the tool was verified and the author was forced to re-frame her understanding of the local reality. The cognitive difficulties of some of the interviewees led to the adjustment of the data collection strategy, through a note handbook and complementary questions. Following observations, the cultural dimension seems to be central to the understanding of management in that context, since cultural elements manifested themselves in the daily practices of the enterprises. The conclusions point out to the distance between theoretical models – in this case those of the so-called "excellence" – and the reality of management practices. At the same time, it was possible to relate the inadequate revealed model to its Japanese cultural assumptions, very different from those in place where the research was conducted. This may explain, in part, its failure

Texture parameter variation region for orthotropic polycrystals with cubic symmetry of the crystal lattice

The variation region of texture parameters (which are integral characteristics of the preferable orientation of crystallographic axes) allows solutions to be found for managing anisotropic properties, illustrating all possible textured states of an orthotropic polycrystalline material with a crystal lattice of cubic symmetry. Each point in this region is matched by certain anisotropy of both elastic and plastic properties. The region of texture parameter variation is defined both analytically and using a numerical experiment of statistic simulation. Analytically, the solution is found via determining the effective eigenvalues of the elasticity operator for a textured anisotropic cubic polycrystal. The algorithm to be followed for visualizing the region-forming elements implies determining the lines of intersection of planes with a conical surface. The numerical solution is based on the determination of texture parameters, i.e, on the starting assumption that the variation region is bounded and lies in the first octant. The task of constructing the variation region is solved via finding the texture parameters using the Monte-Carlo method according to the density of distribution of crystallographic axes in space. When modeling the variation region, octets are used, which are symmetrical reflections of randomly taken orientations in all the octants of space. The constructed regions have the required symmetry. The numerically obtained cloud of textured states and the analytically constructed variation region have geometric centers coinciding at the point corresponding to the non-textured state. At various stages of thermal and mechanical treatment of metallic materials, texture evolution can be represented geometrically as a texture state trajectory that is seen to be within the determined texture parameter variation region. © 2018 Author(s)

Geometric representation of polycrystalline material texture by axis-angle parametrization

Texture is the preferential orientation of crystallographic axes in polycrystal. For its mathematical modeling, the orientation distribution function of the crystallographic axes is used. Traditionally, the orientation distribution function is written with the help of directional cosine matrices, Miller indices or Euler-Krylov angles. Recently, texture has increasingly often been described using quaternions, Rodrigues parameters and the vector space of axis-angle parameters. Axis-angle parameters allow us to describe all possible rotations of the SO(3) group, which corresponds to all possible orientations of crystallographic axes in polycrystalline materials. The SO(3) group is a set of rotations to all possible angles around all possible axes given by all vectors of the unit sphere. The set of such rotations corresponds to points set on a ball of radius π in three-dimensional Euclidean space. The description of the crystallographic texture using axis-angle parameters made it possible to visualize the distribution of crystallographic axes and obtain a new geometric representation of the texture. © 2018 Author(s)

Model-Based Design of Kinematics and Dynamics of Universal Joints in Technological Machines

The study implements a mathematical and visual analysis of the universal joint's work in the software package MathCad and MATLAB Simulink. We obtained the dynamic model taking into account internal characteristics. It demonstrates the connection of the torque on the crosspiece with the angular velocity of the driveshaft and allows to find and fix errors in the early stages of design. © 2022 American Institute of Physics Inc.. All rights reserved

Analysis of the phase images obtained during the collection of a holographic registration system based on the geometric phase effect and a polarization camera

The results of measuring the surface depth of the test object using digital holography are presented. The resulting image was compared to a model based on the calibration slide documentation. In the presented holographic microscope, instead of an eyepiece, a lens with a geometric phase effect is used, which converts a beam with linear polarization into a pair of beams with circular polarizations (diverging and converging). The parallel phase shift method was used to obtain phase distribution. Using a polarization camera, four interferograms corresponding to four different linear projections of interfering waves with right and left circular polarizations were recorded in one exposure. Holograms of a phase object-micrometer were obtained, according to which, by the method of parallel phase shift, the distribution of phase lag introduced by the object was restored. To correct the aberration, subtraction of the recorded phase raid of the illuminating wave — the experimentally obtained phase of the wavefront without an object is used. The developed digital holographic phase microscope based on a geometric phase lens and a polarization camera makes it possible to correctly visualize the surface relief profile. The microscope can be used as a tool for monitoring the state of biological objects exposed to external effects

Avoiding the Intercostal Arteries in Percutaneous Thoracic Interventions.

The purpose of this study was to define relevant intercostal artery (ICA) anatomy potentially impacting the safety of thoracic percutaneous interventional procedures. An ICA abutting the upper rib and running in the subcostal groove was defined as the lowest risk zone for interventions requiring a supracostal needle puncture. A theoretical high-risk zone was defined by the ICA coursing in the lower half of the intercostal space (ICS), and a theoretical moderate-risk zone was defined by the ICA coursing below the subcostal groove but in the upper half of the ICS. Arterial phase computed tomography data from 250 patients were analyzed, revealing demographic variability, with high-risk zones extending more laterally with advancing age and with more cranial ribs. Overall, within the 97.5th percentile, an ICS puncture >7-cm lateral to the spinous process incurs moderate risk and >10-cm lateral incurs the lowest risk