Solving game problems using recursion

The article describes the methodology to game problems of Olympiads in informatics using recursive numbers generation. The study is based on the sequential solution of increasingly complex tasks. For each task, the following materials are given: the condition of the task, the idea of the solution with a proposal to come up with an independent implementation, the solution in the Pascal programming language. Distance learning system DL.GSU.BY is the effective technical base for teaching. It allows offer the student a condition of the task; send the solution for review; get a verdict from the system — a correct or incorrect solution; for incorrect solutions, the number of the test on which the solution did not pass is indicated. A student can take a test (input and output data), on which his solution did not pass, figure out what the error is in his program, correct and send the solution again. In addition, for each problem there is a link on it to the topic in the forum at site, where you can ask a question on solving this problem and / or read the answer if the questions have already been asked before.

Solution of tasks using recursive numbers generation

The article describes the methodology to solve tasks of Olympiads in informatics using recursive numbers generation. The study is based on the sequential solution of increasingly complex tasks. For each task, the following materials are given: the condition of the task, the idea of the solution with a proposal to come up with an independent implementation, the solution in the Pascal programming language. Distance learning system DL.GSU.BY is the effective technical base for teaching. It allows offer the student a condition of the task; send the solution for review; get a verdict from the system — a correct or incorrect solution; for incorrect solutions, the number of the test on which the solution did not pass is indicated. A student can take a test (input and output data), on which his solution did not pass, figure out what the error is in his program, correct and send the solution again. In addition, for each task there is a link on it to the topic in the forum, where you can ask a question on solving this problem and / or read the answer if the questions have already been asked before.

Research on Innovative Trim Method for Tiltrotor Aircraft Take-Off Based on Genetic Algorithm

Tiltrotor aircraft possesses redundant actuators in take-off phase and its flight control is more complicated than ordinary aircraft because the structural and dynamic characteristics keep changing due to tilting rotors. One of the fundamental bases for flight control is trim, which provides steady flight states under various conditions and then constructs the reference trajectory. Tiltrotor aircraft trim models are described by multivariate nonlinear equations whose initial values are difficult to determine and bad initials could lead to incorrect solution for flight control. Therefore, an innovative trim method is proposed to solve this issue. Firstly, genetic algorithm (GA), which possesses strong capability in searching global optimum, is adopted to identify a coarse solution. Secondly, the coarse solution is further refined by the Levenberg-Marquardt (LM) method for precise local optimum. The innovative trim method combines the advantages of these two algorithms and is applied to a tiltrotor aircraft’s flight control in the transition process of incline take-off. The limitation of trajectory is discussed, and tilt corridor is constructed. Finally, the incline take-off simulations are conducted and the effectiveness of the proposed trim method is verified through good match with the designed reference trajectory.

Analytic solutions for calcium ion fertilisation waves on the surface of eggs – erratum

The paper, “Analytic solutions for calcium ion fertilisation waves on the surface of eggs” by the current authors (this journal 2019), adopted an incorrect solution to Legendre’s equation that had been tabulated in a well known compendium of solutions of differential equations. The solution to the linear equation and the consequent solution of the considered nonlinear problem, are corrected here. The solution maintains the same character and the conclusions are the same. Numerical evaluations and graphic outputs have been modified.

Orchestrating Mathematical Classroom Discourse About Various Solution Methods: Case Study of a Teacher’s Development

Developing and orchestrating classroom discourse about students’ different solution methods is an essential yet complex task for mathematics teachers. This study reports on the first stages of classroom discourse development of one Dutch higher secondary school mathematics teacher who had no prior experience in including classroom discourse in her teaching practice. Four lessons in analytic geometry were developed iteratively, in collaboration with the teacher. The lessons consisted of students working on a mathematical problem plus classroom discourse concerning students’ different solution methods. Classroom discourse video recordings were collected and analyzed in order to develop a framework to characterize the teacher’s actions, and to describe the change in the teacher’s role in classroom discourse. The results reveal three main changes in the teacher’s role: First, the way the teacher reacted to correct or incorrect solution methods shifted from confirming or setting aside suggestions, toward making the solution methods the subject of discussion; second, the distribution of turns changed such that more students were involved in the discourse and in reacting to each other’s solution methods; third, the teacher’s actions shifted from convergent, teacher-led actions toward divergent, student-led actions. These results show that within four lessons, an important step has been taken toward establishing a discourse community.

PHARMACIST INTERVENTION AND PREPARATION OF MANUAL IN THE ADMINISTRATION OF DRUGS THROUGH ENTERAL FEEDING TUBE

Objective: To monitor errors in current practice and prepare a manual for proper drug administration through the enteral feeding tube.Methods: It is a prospective observational study conducted for a period of 6 mo in eight departments. The current drug administrations were monitored and checked for the errors which include crushed non crushable solid dosage forms, each drug is not prepared separately, incorrect solution used for dilution, drugs mixed with feeding formula, each drug is not administered separately, not flushed before administration of each drug, not flushed after administration of each drug and others (tablets are not crushed with proper device, motors and pestles are not cleaned frequently, spillage during crushing). Using the data, a manual was prepared and submitted to the physicians of each department.Results: The most prominent error was found to be that the drugs were not prepared and administered separately, tube not flushed before drug administration. Uses of noncrushable tablets were high in neurology. Pantoprazole (enteric coated) and prazosin (modified release) tablets were the most commonly used noncrushable drugs.Conclusion: The study observed the need for developing a standard protocol for drug administration through enteral feeding tube by the pharmacist along with the physician, nursing team to improve the quality of enteral therapy.

Three-Dimensional Genetic Algorithm for the Kirkman's Schoolgirl Problem

This paper focuses on the possibilities of multidimensional genetic algorithms and relevant genetic operators. After the literature overview we used a three-dimensional genetic algorithm to solve a combinatorial task called Kirkman’s Schoolgirl Problem. The first results were not good, but we improved convergence of an algorithm by adding more genetic operators. We also used problem dependent mutation, where we tried to repair the incorrect solution by using the simple heuristic method. Finally, we got a solid number of correct solutions, but we know there is enough room for other improvements.

Proposal of a Procedure for Automating an Industrial Process Using Petri Nets as a Formal Tool

Currently, industrial systems must adapt to changes in globalized markets in order to be competitive. In this context, automation is presented as a solution to ensure the efficiency and effectiveness of production. However, a correct specification of this kind of response is not a trivial task. This is due to the increase in the process dynamic complexity that involves personnel and technical resources of different nature as well as, risks derived from an incorrect solution definition. Thus, this article presents a structured process that considers the semantics of UML, Petri Nets as a modeling tools and automation standards to define the requirements, behavior and implementation of the system automation project. In order to assess the proposed approach, an application example was developed. Finally, the relevant contributions are stated in the context of the application.

Ambiguities in helical reconstruction

Helical polymers are found throughout biology and account for a substantial fraction of the protein in a cell. These filaments are very attractive for three-dimensional reconstruction from electron micrographs due to the fact that projections of these filaments show many different views of identical subunits in identical environments. However, ambiguities exist in defining the symmetry of a helical filament when one has limited resolution, and mistakes can be made. Until one reaches a near-atomic level of resolution, there are not necessarily reality-checks that can distinguish between correct and incorrect solutions. A recent paper in eLife (Xu et al., 2014) almost certainly imposed an incorrect helical symmetry and this can be seen using filament images posted by Xu et al. A comparison between the atomic model proposed and the published three-dimensional reconstruction should have suggested that an incorrect solution was found.