Herugolf and Makaro are NP-complete

Herugolf and Makaro are Nikoli\u27s pencil puzzles. We study the computational complexity of Herugolf and Makaro puzzles. It is shown that deciding whether a given instance of each puzzle has a solution is NP-complete

Searching Polyhedra by Rotating Half-Planes

The Searchlight Scheduling Problem was first studied in 2D polygons, where the goal is for point guards in fixed positions to rotate searchlights to catch an evasive intruder. Here the problem is extended to 3D polyhedra, with the guards now boundary segments who rotate half-planes of illumination. After carefully detailing the 3D model, several results are established. The first is a nearly direct extension of the planar one-way sweep strategy using what we call exhaustive guards, a generalization that succeeds despite there being no well-defined notion in 3D of planar "clockwise rotation". Next follow two results: every polyhedron with r>0 reflex edges can be searched by at most r^2 suitably placed guards, whereas just r guards suffice if the polyhedron is orthogonal. (Minimizing the number of guards to search a given polyhedron is easily seen to be NP-hard.) Finally we show that deciding whether a given set of guards has a successful search schedule is strongly NP-hard, and that deciding if a given target area is searchable at all is strongly PSPACE-hard, even for orthogonal polyhedra. A number of peripheral results are proved en route to these central theorems, and several open problems remain for future work.Comment: 45 pages, 26 figure

Design as communication in micro-strategy — strategic sensemaking and sensegiving mediated through designed artefacts.

This paper relates key concepts of strategic cognition in microstrategy to design practice. It considers the potential roles of designers' output in strategic sensemaking and sensegiving. Designed artifacts play well-known roles as communication media; sketches, renderings, models, and prototypes are created to explore and test possibilities and to communicate these options within and outside the design team. This article draws on design and strategy literature to propose that designed artifacts can and do play a role as symbolic communication resources in sensemaking and sensegiving activities that impact strategic decision making and change. Extracts from interviews with three designers serve as illustrative examples. This article is a call for further empirical exploration of such a complex subject

What does a cue do? Comparing phonological and semantic cues for picture naming in aphasia

Purpose: Impaired naming is one of the most common symptoms in aphasia, often treated with cued picture naming paradigms. It has been argued that semantic cues facilitate the reliable categorisation of the picture, and phonological cues facilitate the retrieval of target phonology. To test these hypotheses, we compared the effectiveness of phonological and semantic cues in picture naming for a group of individuals with aphasia. To establish the locus of effective cueing, we also tested whether cue type interacted with lexical and image properties of the targets. Method: Individuals with aphasia (n=10) were tested with a within-subject design. They named a large set of items (n=175) four times. Each presentation of the items was accompanied by a different cueing condition (phonological, semantic, non-associated word and tone). Item level variables for the targets (i.e., phoneme length, frequency, imageability, name agreement and visual complexity) were used to test the interaction of cue type and item variables. Naming accuracy data was analysed using generalised linear mixed effects models. Results: Phonological cues were more effective than semantic cues, improving accuracy across individuals. However, phonological cues did not interact with phonological or lexical aspects of the picture names (e.g., phoneme length, frequency). Instead, they interacted with properties of the picture itself (i.e., visual complexity), such that phonological cues improved naming accuracy for items with low visual complexity. Conclusions: The findings challenge the theoretical assumptions that phonological cues map to phonological processes. Instead, phonological information benefits the earliest stages of picture recognition, aiding the initial categorization of the target. The data help to explain why patterns of cueing are not consistent in aphasia, i.e., it is not the case that phonological impairments always benefit from phonological cues and semantic impairments form semantic cues. A substantial amount of the literature in naming therapy focuses on picture naming paradigms. Therefore, the results are also critically important for rehabilitation, allowing for therapy development to be more rooted in the true mechanisms through which cues are processed

Assessing Adaptive Learning Styles in Computer Science Through a Virtual World

abstract: Programming is quickly becoming as ubiquitous and essential a skill as general mathematics. However, many elementary and high school students are still not aware of what the computer science field entails. To make matters worse, students who are introduced to computer science are frequently being fed only part of what it is about rather than its entire construction. Consequently, they feel out of their depth when they approach college. Research has discovered that by teaching computer science and programming through a problem-driven approach and focusing on a combination of syntax and computational thinking, students can be prepared when entering higher levels of computer science education. This thesis describes the design, development, and early user testing of a theory-based virtual world for computer science instruction called System Dot. System Dot was designed to visually manifest programming instructions into interactable objects, giving players a way to see coding as tangible entities rather than text on a white screen. In order for System Dot to convey the true nature of computer science, a custom predictive recursive descent parser was embedded in the program to validate any user-generated solutions to pre-defined logical platforming puzzles. Steps were taken to adapt the virtual world to player behavior by creating a system to detect their learning style playing the game. Through a dynamic Bayesian network, System Dot aims to classify a player’s learning style based on the Felder-Sylverman Learning Style Model (FSLSM). Testers played through the first half of System Dot, which was enough to test out the Bayesian network and initial learning style classification. This classification was then compared to the assessment by Felder’s Index of Learning Styles Questionnaire (ILSQ). Lastly, this thesis will also discuss ways to use the results from the user testing to implement a personalized feedback system for the virtual world in the future and what has been learned through the learning style method.Dissertation/ThesisMasters Thesis Computer Science 201

Choosing to see: designing accessible video games for visually impaired players

As players when thinking of playing video games some memories come to mind, and those images and memories involve people playing around a screen, something very normal when performing such action. But what happens to those that can’t see properly? Or those that can see at all? How can they play? The word video game already includes “video” on it, something that involves the use of the sight. And in their origin video games were something that was created having in mind that the players would be able to use the visual feedback as a way to interact with the game itself. But technology and science have evolved in the last 50 years and nowadays it is possible for a completely blind player to play and finish a 30 h long video game. Of course this is not the case for the great majority of video games. Most video games developed in the last 20 years have little to no accessibility options, and even the ones that are currently released by big companies and studios rarely meet the expectations. Living in the 21st century in an advanced and technologic world where even VR games can be played at home, not having proper Accessibility options for the players seems wrong. As developers Accessibility is something that should be taken into account in each game and project worked on from now on. The objective of this paper is not to expose or criticize video game studios in the industry but quite the opposite. The goal of this paper is to inform and educate others and myself on a topic that must concern every developer and that should be something to take into account from the beginning of the development, how to make a video game more accessible for all players, especially for players with visual disabilitie

Nostalgia

The visual part of this project has revolved around ideas that have been in the process of forming themselves for a few years. But if I could assign a topic or a totalizing theme to the project, I would be limiting it in a very particular way. I see Nostalgia as a beginning and in no way something that has come to fruition or to a speci!c resolution. If anything I consider it as a still evolving subject; it is very youthful and fresh for me. The project also rejects a new way of working for me from creating the set to the final production of images. The aim of the piece was to engage in a dialogue with a tradition of image making and reject upon photographs and its role in forming of collective memory. I wanted to examine the role of the space in the formation of one\u27s recollection of the past and to emphasize the impact of such onto present behaviors and understanding of the space and the codes of power that it conceals. My evaluation will directly address historical, psychoanalytical, and biological questions of dominant visuality and sight in the contemporary societies of spectacle. I want to relate to Maurice Blanchot\u27s passage about how everyday losses its power to reach us; it is no longer what is lived, but what can be seen or what shows itself, spectacle and description, without any active relation whatsoever or, to go even further, to employ words of Alice Yaeger Kaplan who blames the denigration of memory in this society of spectacle, where visuality and recall is so heavily centers itself around visual sensory experience and memory heavily relies on use of images as a primary basis for the authenticity. I would like to amplify necessity of vrigorous interrogation of the images and concepts that inform and later constitute our memories as individuals and as a collective society as a whole. The body of work presented as photographs under the title of Nostalgia that hung on the walls of the SPAS gallery in October-November of 2008 are a manifest to my thought process and my rejections on the impact and danger of image-based recall. I further examine the-knownto-me nature of what appears to be personal recollections and the role of them in the creating the !nal images. As they exist in their !nal form they present no validity and yet violently defend their role in my memory and, perhaps, from now on in the memory of many others

Is the border effect an artefact of geographic aggregation?

The existence of a large border effect is considered as one of the main puzzles of international macroeconomics. We show that the border effect is, to a large extent, an artefact of geographic concentration. In order to do so we combine international flows with intra-national flows data characterised by a high geographic grid. At this fine grid, intra-national flows are highly localised and dropping sharply with distance. The use of a small geographical unit of reference to measure intra-national bilateral trade flows allows to estimating correctly the negative impact of distance on shipments. When we use sector disaggregated export flows of 50 Spanish provinces in years 2000 and 2005 split into inter-provincial and inter-national flows, we find that the border effect is reduced substantially and even becomes statistically not different from zero in some estimations