Extended linked voxel structure for point-to-mesh distance computation and its application to NC collision detection

When working with milling or polishing robots and large workpieces it is necessary to check not only the milling or polishing tool for collision, but it is also necessary to check the remaining arms of the robot for collision. In most of the cases the arms of the robot do not collide with the workpiece and so applying an existing collision detection algorithm to the arms of the robot slows the process down. In this paper, we present an algorithm for quickly assuring non-collisions, which is especially targeted at collisions of the arms of the robot with a workpiece. The algorithm is based on an extended voxel structure. More precisely, we extend a voxel structure by adding distance values to the corner of the voxels and by linking empty voxels to non-empty voxels to accelerate finding the desired voxel. This ensures that we only need to consider a small subset of the triangles describing the workpiece’s surface, namely those triangles that are close to the possible collision area. The triangles within each non-empty voxel are stored in a bsp-tree. For empty voxels, we save information about the distances to the mesh. This setup speeds up the point-to-mesh distance calculation, especially for points close to the mesh. The extra distance information in empty voxels enables a fast distance estimation and hence a fast early collision check.     

An old game,new experience: exploring the effect of players’ personal gameplay history on game experience

This experimental study explores how game experience differs between players with different gameplay histories within the same game universe. We are interested in how prolonged engagement with a game series affects the gameplay experience in relation to the most recent game version in the series. A total of 54 participants were divided into four groups depending on their gaming experience, namely non-gamers, new-gamers, old-gamers and core-gamers. They played the mobile version of Super Mario Run, and questionnaire data was collected after the gameplay session. The results of the study showed that not only the players’ personal gameplay history but also the length of experience or degree of familiarity with the game universe affected the experience of playing a new game in the same game universe. Additionally, familiarity with the game universe had a positive impact on the feeling of competence, immersion, emotions and flow.

     

Exploring the types and reasons of Internet-triggered academic dishonesty among Turkish undergraduate students: Development of Internet-Triggered Academic Dishonesty Scale (ITADS)

Internet contributes to the development of science and facilitates scientific demeanors while it also serves as a ground for academic misdemeanors. Recent studies indicate that Internet facilitates and spreads academic dishonesty. The purpose of the current study is to investigate the extent of involvement of Turkish university students in academic dishonesty practices facilitated through Internet (i.e. e-dishonesty) and to question the conditions which lead to e-dishonesty. Three hundred and forty nine education faculty students from the most populated state university in Turkey were administered two Likert-Scale questionnaires developed by the researchers. After the reliability and validity conditions were met, two exploratory factor analyses were conducted. The first one revealed the factors constituting common types of e-dishonesty among undergraduate students which were fraudulence, plagiarism, falsification, delinquency, and unauthorized help. The second factor analysis exhibited individual and contextual factors triggering e-dishonesty which were named as individual factors, institutional policies and peer pressure. Results of both analyses are discussed and suggestions for further research are provided.     

Solutions of the Cahn–Hilliard equation

In this paper, we found some exact solutions of the Cahn–Hilliard equation and the system of the equations by considering a modified extended tanh function method. A numerical solution to a Cahn–Hilliard equation is obtained using a homotopy perturbation method (HPM) combined with the Adomian decomposition method (ADM). The comparisons are given in the tables.     

On the class of λ-statistically convergent difference sequences of fuzzy numbers

In this study, we introduce the sets $\left[ V,\lambda ,p\right] _{\Updelta }^{{\mathcal{F}}},\left[ C,1,p\right] _{\Updelta }^{{\mathcal{F}}}$ and examine their relations with the classes of $ S_{\lambda }\left( \Updelta ,{\mathcal{F}}\right)$ and $ S_{\mu }\left( \Updelta ,{\mathcal{F}}\right)$ of sequences for the sequences $\left( \lambda _{n}\right)$ and $\left( \mu _{n}\right) , 0<p<\infty $ and difference sequences of fuzzy numbers.     

The Effect of Post Annealing in Reduced Oxygen Atmosphere on Critical Current Density of (Bi, Pb)2Sr2Ca2Cu3Oy Long Bulks

Sinter forging has been employed to improve critical current density of Bi-2223 bulks. After that, optimal post annealing is also very important to get good performance. Different annealing schedules have been used to produce Bi-2223 sinter-forged bulks in different atmospheres. In this paper, Bi-2223 long bulks were prepared by a combination of cold isostatic pressing (CIP) and sinter-forging techniques. The samples were undergone deformation rates from 50 to 90% totally. The effect of post annealing in atmosphere of 7.5% O₂/N₂ on critical current density J_c for such (Bi, Pb)₂Sr₂Ca₂Cu₃O_y long bulks was investigated. Their microstructure features and phase changes were also studied.     

Direction finding of moving ferromagnetic objects inside water by magnetic anomaly

The remote sensing methods by the use of magnetic anomaly are gaining importance in applications of defense technologies and industrial purposes recently. In this study, it is aimed to determine the remote detection, the variation of characteristic of the voltage in the sensor relative to the motion, the effects of material length, magnetic permeability and direction of motion of the object on this characteristic and to convert them to a useful mathematical expression by using magnetic anomaly of ferromagnetic objects such as submarines moving inside water. For this purpose, first of all, a water tank of 1 m³ is prepared and approximately a homogeneous magnetic field of 10⁻³ T is created within this water tank. Ferromagnetic materials with six different lengths and permeabilities are moved in three different directions relative to the position of the sensor by means of a computer controlled x–y scanner designed for this experiment inside this magnetic field. The magnetic change caused by this motion at the point where the sensor is positioned is detected as the output voltage of the sensor. A mathematical expression is formulated taken into account the variations of the sensor output voltage with respect to the length, magnetic permeability and the direction of motion of the material and it is validated by the experimental results. This study clearly shows that the existence and the direction of motions of ferromagnetic objects with different lengths and magnetic permeabilities inside water can be detected with high accuracy.     

Electrorheological properties of pumice/silicone oil suspension

Pumice particles-based electrorheological (ER) suspensions were prepared in silicone oil and its ER behavior was investigated as a function of shear rate, electric field strength, concentration and temperature. Sedimentation stabilities of suspensions were determined. ER activity of all the suspensions was observed to increase with increasing electric field strength, concentration and decreasing shear rate. Yield stress of pumice suspensions increased linearly with increasing applied electric field strength and with concentrations of the particles. The pumice suspensions show a typical shear thinning non-Newtonian viscoelastic behavior, in which viscosity of suspension decreased sharply with increasing shear rate. Effect of high temperature onto ER activity of pumice/silicone oil system was also investigated.     

Evaluating micas in petrologic and metallogenic aspect: Part II—Applications using the computer program Mica

The significance of micas for metallogenic and petrologic studies results from their widespread occurrence in magmatic, metamorphic, and hydrothermal ore-related rocks. For example, the mineral chemistry of biotites, and especially their halogen content, may provide an important guide in understanding the composition and circulation of fluids during or later emplacement of magmatic rocks and associated with hydrothermal mineralization. The Mica⁺ program has been developed to evaluate mica composition both from magmatic rocks and associated with porphyry copper and Mo–Au–Sn–W–Be systems. The validity of the Mica⁺ program has been tested for variety mica data sets selected from literature. The concept of computer program can be grouped into three major topics, respectively: (i) mica classification and discrimination; (ii); estimation of intensive parameters; and (iii) halogen contents as an indication of hydrothermal ore deposits.Halogen systematics and intensive thermodynamic parameters (i.e., T, f O₂, f H₂O) of micas both from porphyry Cu–Au–Mo mineralization system and magmatic rocks were estimated using the Mica⁺ program. Program output was compared with the original published results. Evaluation suggests that the Mica⁺ can be used efficiently in studying the mica composition in respect to petrologic and metallogenic aspects.