A Novel Algorithm to Verify the Solution of Geometric Puzzle Games

In this paper, we present a novel algorithm to solve the problem of correctly verifying the solution for geometric puzzles. When compared with others, this approach covers a satisfactory amount of cases. The method comprises the use of sixteen possible relations between polygon edges, which are classified to eliminate those that are not necessarily part of the final figure. This method provides for a precise verification of an arranged set of polygons that must form the same image as the desired solution, without the need of extra meta-data. Only the vertexes themselves (also the edge concavity and center position, when circumference arcs are present) are used the algorithm

Best-first heuristic search for multicore machines

To harness modern multicore processors, it is imperative to develop parallel versions of fundamental algorithms. In this paper, we compare different approaches to parallel best-first search in a shared-memory setting. We present a new method, PBNF, that uses abstraction to partition the state space and to detect duplicate states without requiring frequent locking. PBNF allows speculative expansions when necessary to keep threads busy. We identify and fix potential livelock conditions in our approach, proving its correctness using temporal logic. Our approach is general, allowing it to extend easily to suboptimal and anytime heuristic search. In an empirical comparison on STRIPS planning, grid pathfinding, and sliding tile puzzle problems using 8-core machines, we show that A*, weighted A* and Anytime weighted A* implemented using PBNF yield faster search than improved versions of previous parallel search proposals

Fair and Sound Secret Sharing from Homomorphic Time-Lock Puzzles

Achieving fairness and soundness in non-simultaneous rational secret sharing schemes has proved to be challenging. On the one hand, soundness can be ensured by providing side information related to the secret as a check, but on the other, this can be used by deviant players to compromise fairness. To overcome this, the idea of incorporating a time delay was suggested in the literature: in particular, time-delay encryption based on memory-bound functions has been put forth as a solution. In this paper, we propose a different approach to achieve such delay, namely using homomorphic time-lock puzzles (HTLPs), introduced at CRYPTO 2019, and construct a fair and sound rational secret sharing scheme in the non-simultaneous setting from HTLPs. HTLPs are used to embed sub-shares of the secret for a predetermined time. This allows to restore fairness of the secret reconstruction phase, despite players having access to information related to the secret which is required to ensure soundness of the scheme. Key to our construction is the fact that the time-lock puzzles are homomorphic so that players can compactly evaluate sub-shares. Without this efficiency improvement, players would have to independently solve each puzzle sent from the other players to obtain a share of the secret, which would be computationally inefficient. We argue that achieving both fairness and soundness in a non-simultaneous scheme using a time delay based on CPU-bound functions rather than memory-bound functions is more cost effective and realistic in relation to the implementation of the construction

Automatic level generation for platform videogames using genetic algorithms

In this document we present an investigation on automatically generating levels for platform videogames. Common approaches for this problem are rhythm based, where input patterns are transformed in a valid geometry, and chunk based, where samples are humanly created and automatically assembled like a puzzle. The proposal hereby presented is to explore this challenge with the usage of Genetic Algorithms, facing it as a search problem, in order to achieve higher expressivity and less linearity than in rhythm based approach and without requiring human creation as it happens with the chunk based approach. With simple heuristics the system is able to generate playable levels in a small amount of time (one level is created in less than a minute) and with considerable diversity, as our results show

Influence of the Algorithmization Process on the Mathematical Competence: A Case Study of Trainee Teachers Assessing ABN- and CBC-Instructed Schoolchildren by Gamification

In this manuscript, schoolchild mathematical competencies have been assessed by using educational gamification methodologies; specifically, Educational Escape Rooms (EER). To ease the interpretation of results, Spanish schoolchildren trained by using two different methodologies (ABN and CBC) were selected to participate in the experience. The gamified environment used as assessment tool was co-designed by trainee teachers, on-service teachers, and university researchers. The design was implemented in different educational centers and the results were transcribed to deliver a didactic analysis. Among the findings of this study, we uncovered: (i) the reduction of the math anxiety, (ii) the different performance of the schoolchild involved-ABN students show an additional and positive 10% development of certain mathematical competences-and (iii) a positive didactic-mathematic development of the participant trainee teachers

Planning under time pressure

Heuristic search is a technique used pervasively in artificial intelligence and automated planning. Often an agent is given a task that it would like to solve as quickly as possible. It must allocate its time between planning the actions to achieve the task and actually executing them. We call this problem planning under time pressure. Most popular heuristic search algorithms are ill-suited for this setting, as they either search a lot to find short plans or search a little and find long plans. The thesis of this dissertation is: when under time pressure, an automated agent should explicitly attempt to minimize the sum of planning and execution times, not just one or just the other. This dissertation makes four contributions. First we present new algorithms that use modern multi-core CPUs to decrease planning time without increasing execution. Second, we introduce a new model for predicting the performance of iterative-deepening search. The model is as accurate as previous offline techniques when using less training data, but can also be used online to reduce the overhead of iterative-deepening search, resulting in faster planning. Third we show offline planning algorithms that directly attempt to minimize the sum of planning and execution times. And, fourth we consider algorithms that plan online in parallel with execution. Both offline and online algorithms account for a user-specified preference between search and execution, and can greatly outperform the standard utility-oblivious techniques. By addressing the problem of planning under time pressure, these contributions demonstrate that heuristic search is no longer restricted to optimizing solution cost, obviating the need to choose between slow search times and expensive solutions