The complexity of playing durak

International audienceDurak is a Russian card game in which players try to get rid of all their cards via a particular at-tack/defense mechanism. The last player standing with cards loses. We show that, even restricted to the perfect information two-player game, finding optimal moves is a hard problem. More precisely , we prove that, given a generalized du-rak position, it is PSPACE-complete to decide if a player has a winning strategy. We also show that deciding if an attack can be answered is NP-hard

Pirate plunder: game-based computational thinking using scratch blocks

Policy makers worldwide argue that children should be taught how technology works, and that the ‘computational thinking’ skills developed through programming are useful in a wider context. This is causing an increased focus on computer science in primary and secondary education. Block-based programming tools, like Scratch, have become ubiquitous in primary education (5 to 11-years-old) throughout the UK. However, Scratch users often struggle to detect and correct ‘code smells’ (bad programming practices) such as duplicated blocks and large scripts, which can lead to programs that are difficult to understand. These ‘smells’ are caused by a lack of abstraction and decomposition in programs; skills that play a key role in computational thinking. In Scratch, repeats (loops), custom blocks (procedures) and clones (instances) can be used to correct these smells. Yet, custom blocks and clones are rarely taught to children under 11-years-old. We describe the design of a novel educational block-based programming game, Pirate Plunder, which aims to teach these skills to children aged 9-11. Players use Scratch blocks to navigate around a grid, collect items and interact with obstacles. Blocks are explained in ‘tutorials’; the player then completes a series of ‘challenges’ before attempting the next tutorial. A set of Scratch blocks, including repeats, custom blocks and clones, are introduced in a linear difficulty progression. There are two versions of Pirate Plunder; one that uses a debugging-first approach, where the player is given a program that is incomplete or incorrect, and one where each level begins with an empty program. The game design has been developed through iterative playtesting. The observations made during this process have influenced key design decisions such as Scratch integration, difficulty progression and reward system. In future, we will evaluate Pirate Plunder against a traditional Scratch curriculum and compare the debugging-first and non-debugging versions in a series of studies

Coronal loop detection from solar images and extraction of salient contour groups from cluttered images.

This dissertation addresses two different problems: 1) coronal loop detection from solar images: and 2) salient contour group extraction from cluttered images. In the first part, we propose two different solutions to the coronal loop detection problem. The first solution is a block-based coronal loop mining method that detects coronal loops from solar images by dividing the solar image into fixed sized blocks, labeling the blocks as Loop or Non-Loop , extracting features from the labeled blocks, and finally training classifiers to generate learning models that can classify new image blocks. The block-based approach achieves 64% accuracy in IO-fold cross validation experiments. To improve the accuracy and scalability, we propose a contour-based coronal loop detection method that extracts contours from cluttered regions, then labels the contours as Loop and Non-Loop , and extracts geometric features from the labeled contours. The contour-based approach achieves 85% accuracy in IO-fold cross validation experiments, which is a 20% increase compared to the block-based approach. In the second part, we propose a method to extract semi-elliptical open curves from cluttered regions. Our method consists of the following steps: obtaining individual smooth contours along with their saliency measures; then starting from the most salient contour, searching for possible grouping options for each contour; and continuing the grouping until an optimum solution is reached. Our work involved the design and development of a complete system for coronal loop mining in solar images, which required the formulation of new Gestalt perceptual rules and a systematic methodology to select and combine them in a fully automated judicious manner using machine learning techniques that eliminate the need to manually set various weight and threshold values to define an effective cost function. After finding salient contour groups, we close the gaps within the contours in each group and perform B-spline fitting to obtain smooth curves. Our methods were successfully applied on cluttered solar images from TRACE and STEREO/SECCHI to discern coronal loops. Aerial road images were also used to demonstrate the applicability of our grouping techniques to other contour-types in other real applications

QR Codes Utilization in EFL Classroom: Affective Language Learning Attributes in Writing

Background:Numerous positive gains have been reported on the use of technology in language learning. The current survey of published journal articles reveals a lack of research on its integration to language teaching and learning in graduate language classrooms in EFL settings. In this study, the use of QR codes in the graduate EFL classroom has been investigated concerning its relatedness to affective language learning attributes (herein referred to as ALLAs) including anxiety, engagement, motivation, self-esteem, among others during the lesson on the process of writing. Three objectives were sought (1) to know students’ perceptions on ALLAs before and after the use of QR codes, (2) to establish the relationship between students’ perceived ALLAs and language performance, and (3) to understand specific situations that trigger positive or negative reactions.Methodology:The students were asked to indicate their perceptions concerning ALLAs by using a survey questionnaire before and after the activity. They were also asked to do the QR codes activity to create an essay outline. Further, an open-ended questionnaire was provided to indicate their negative or positive reactions to specific situations during the QR-coded activity.Findings:Results suggest the following (1) there are significant differences in the students’ perceived ALLAs before and after the activity, (2), there is a significant positive correlation between ALLAs and language performance, and (3) twelve specific situations were found to provoke dynamic ALLAs reactions.Conclusion:It is suggested that the use of available technological innovations must be introduced to graduate language teachers as its impacts on ALLAs are overwhelmingly beneficial

Shapeshifting in the Venus flytrap (Dionaea muscipula): Morphological and biomechanical adaptations and the potential costs of a failed hunting cycle

The evolutionary roots of carnivory in the Venus flytrap (Dionaea muscipula) stem from a defense response to plant injury caused by, e.g., herbivores. Dionaea muscipula aka. Darwin’s most wonderful plant underwent extensive modification of leaves into snap-traps specialized for prey capture. Even the tiny seedlings of the Venus flytrap already produce fully functional, millimeter-sized traps. The trap size increases as the plant matures, enabling capture of larger prey. The movement of snap-traps is very fast (~100–300 ms) and is actuated by a combination of changes in the hydrostatic pressure of the leaf tissue with the release of prestress (embedded energy), triggering a snap-through of the trap lobes. This instability phenomenon is facilitated by the double curvature of the trap lobes. In contrast, trap reopening is a slower process dependent on trap size and morphology, heavily reliant on turgor and/or cell growth. Once a prey item is caught, the trap reconfigures its shape, seals itself off and forms a digestive cavity allowing the plant to release an enzymatic cocktail to draw nutrition from its captive. Interestingly, a failed attempt to capture prey can come at a heavy cost: the trap can break during reopening, thus losing its functionality. In this mini-review, we provide a detailed account of morphological adaptations and biomechanical processes involved in the trap movement during D. muscipula hunting cycle, and discuss possible reasons for and consequences of trap breakage. We also provide a brief introduction to the biological aspects underlying plant motion and their evolutionary background

Modification of logical reasoning through an informal gamification platform

Informal Gamification based on video games turns out to be attractive due to its playful presentation, its motivational resources, and open access. This is important for the benefit of cognitive constructs such as logical reasoning, in the area of mathematics. Through this research, we implemented an experimental program based on the inclusion of the Plants vs Zombies video game as a cognitive modifier of reasoning. We developed the Gamification project through a pre-experimental design for six months. The sample consisted of 96 Basic Education students (M = 6.56 years of age; SD = 0.3). The pre-calculation test allowed us to contrast results between the pretest and posttest measurements. We obtained effective results in the dimensions of seriation, cardinality and cognitive conservation. The effects were much more decisive in conservation. These results allowed obtaining that the complexity of this game allowed to reduce the cognitive reload in the mathematical operations, as well as to increase the sustained attention in the development of logical reasoning tasks, and to achieve greater fluency in the operational calculation

The Turkish Olympics: Festival into the Gulen movement

The Turkish Olympics Final is an annual two-week long cultural festival bringing together non-Turkish international students from Gulenist schools in other nations to compete in a variety of performances throughout Turkey. The performances tend to have international school children singing in Turkish, dancing villager dances from Anatolia, reciting Turkish poetry and acting in Turkish plays. International school children can also perform in English or their own native languages but much of the Turkish media attention is given to the school children/performers that learn Turkish. Also important at the Turkish Olympics – while the majority of performers are international non-Turkish children – there is a space given for Turkish children who go to Gulenist schools outside of Turkey. The Turkish Islamist “Gulen Movement” sponsors and organizes the Turkish Olympics Final and also organizes smaller semi-final contests in which students from their international school network compete in home countries to represent each nation at the final. In Egypt, Gulenists have organized a semi-final Turkish Olympics festival at the largest Gulenist school in the country, Salahaldin International School in Cairo. The focus of my thesis is on the Gulenist educational/dormitory/business network in Egypt. The Egyptian Gulenist network is the focus of this study for two reasons. The first reason is utilitarian in nature. As a master’s student at the American University in Cairo, I spent several years in Egypt after I lived and worked with Gulenists in Istanbul. The second reason is geopolitical. Turkey and Egypt are seminal nations in the Middle East. The only other country with a similar population size as well as cultural and economic import would be Iran. As such research on the Gulenists’ actions and business/education network in Egypt – especially after the ouster of President Morsi and the rise of President El Sisi – is an important study which touches on issues of politics, economics, Islamism and education between Turkey and Egypt

Teachers’ End-User Attitudes Toward the Implementation of School-Based Social Networking Sites in K-8 Schools: An Extension of the Technology Acceptance Model

Advancement in technologies, such as smartphones and social networking sites (SNSs), are transforming traditional school-based communication in education. School-based SNSs are a web-based system that enables administrators and teachers to (1) create or join a semi-public online school community within a bounded system, (2) construct a virtual classroom with individual student profiles, or avatars, (3) invite parents and guardians to create a profile and link with their child’s profile, (4) and communicate with students, parents, and guardians about students’ school experiences using the classroom management and communication platform. ClassDojo, a school-based SNS, has over three million teachers and 35 million students using the platform (Williamson, 2017a). Teachers create and manage the virtual community; therefore, it is crucial to understand teachers’ end-user attitudes towards adopting school-based SNSs. An extension of the Technology Acceptance Model (TAM) examined K-8 teachers’ end-user attitudes to integrate school-based SNSs in United States’ primary and middle schools. The TAM’s foundation, extensions, and correlation to teachers’ attitudes towards technology presented as an ideal model to ground the study. Thus, using theoretical and empirical studies related to teachers’ adoption of technology and SNSs, this research study extended TAM using the following factors: (1) perceived usefulness (PU), (2) perceived ease of use (PEOU), (3) security awareness (SA), (4) subjective norm (SN), (5) attitude toward using SNSs (ATT), and (6) intention to use SNSs (ITU). TAM research traditionally relies on obtaining self-reported data from participants through survey. This survey-research collected data from 264 kindergarten to eighth-grade teachers throughout the United States. The survey data was used to analyze descriptive statistics between TAM variables, as well as perform path analyses on the relationships between the TAM variables. In this study, the TAM was extended to include subjective norm (SN) and security awareness (SA). In summary, a majority of K-8 teachers had a generally favorable attitude about ClassDojo’s: (1) perceived usefulness, (2) perceived ease of use, (3) security awareness, (4) subjective norm, (5) attitude towards use, and (6) intention to use. Path analysis with latent factors utilized multiple regressions to assess the direct and indirect influences of variables within a model (Hatcher, 2013). The extended TAM model was reliable and illustrated that seven out of the eight path analyses were statistically significant. Teachers’ attitudes towards ClassDojo use had the most statistically significant influence on teachers’ intentions to use ClassDojo. Similar to findings from traditional TAM studies, perceived usefulness had the largest statistically significant influence on teachers’ attitudes toward ClassDojo use. A thematic analysis of teachers’ comments about ClassDojo provided support for the extended TAM path analysis. In conclusion, this study synthesized other TAM variables to establish, the Teacher Technology Acceptance Model of Social Networking Sites (T-TAMS), to identify and explore factors that positively influenced K-8 teachers’ end-user attitudes towards school-based SNSs use. Lastly, limitations and future research were presented. This study advanced research on teachers’ TAM of SNSs, teachers’ end-user attitudes toward ClassDojo, and school-based communication. Thus, these findings can be used to boost ClassDojo’s adoption rates among K-8 schools in the United States

A DASH server-side delay-based representation switching solution to improve the quality of experience for low-latency live video streaming

[EN] This work addresses the integration of real-time transmission systems, including IP cameras and production systems (like OBS or vMix), that use protocols such as RTSP (Real Time Streaming Protocol) or SRT (Secure Reliable Transport), with content distribution technology based on LL-DASH (Low Latency DASH -Dynamic Adaptive Streaming over HTTP-), taking advantage of the fact that DASH offers significant well-known advan- tages for content distribution over the Internet and via CDNs (Content Delivery Networks). Considering the limitations of the LL-DASH standard regarding the adaptation to network conditions, this paper proposes a new solution called Server-Side Representation Switching (SSRS). SSRS uses an approach based on the server measuring the delay in the requests made by clients, whose variation may be due to a decrease in bandwidth, as occurs in Wi-Fi networks with a high number of clients. To evaluate the effectiveness of the proposed solution, a testbed has been developed that allows the performance evaluation of both the LL-DASH system and the solution based on server-side decision-making. In addition, the developed solution has been compared with known al- gorithms (L2A and LoL+) integrated into the Dash.js player. The results show that the Server-Side Representation Switching solution offers a good trade-off between the transmitted quality and the final delay measured at the client, compared to the other algorithms evaluated. Moreover, it holds the advantage of being straightforward to implement and does not require any modifications to the players used.This work is supported by the Centro para el Desarrollo Tecnologico Industrial (CDTI) from the Government of Spain under the project "Nueva plataforma a bordo basada en redes 5G y Wi-Fi 6 para medios de transporte terrestre" (CDTI IDI-20210624).Belda Ortega, R.; Arce Vila, P.; Guerri Cebollada, JC.; De Fez, I. (2023). A DASH server-side delay-based representation switching solution to improve the quality of experience for low-latency live video streaming. Computer Networks. 235:1-15. https://doi.org/10.1016/j.comnet.2023.10996111523