Hard Puzzle Research Articles

Ecocide — Puzzles and Possibilities

Abstract Popular interest in a new crime of ‘ecocide’ has recently surged. The proposed crime seeks to repudiate and stigmatize the most egregious environmental wrongdoing and would complement other efforts to curb the ongoing destruction. In June 2021, an international panel proposed a definition of the crime. Initial academic commentaries, many of them critical, reflect entirely understandable first reactions. However, combining international criminal law (ICL) and environmental law raises fascinating new issues that are not initially obvious. In this article, I survey the main issues in defining ecocide. For example, is a crime of ecocide a worthy idea? Is the best approach to amend the ICC Statute or to start with a smaller group of supportive states? I also introduce the main drafting options and controversies. The hardest puzzle, by far, is how to align ecocide with environmental law. Some seemingly simple solutions would entail rejecting environmental law; I argue that there are principled, normative, and strategic reasons why a crime of ecocide should reflect environmental law, not reject it. I show that each available solution invites plausible concerns. Thus, a conversation about defining ecocide must be a nuanced one about which options are least problematic. I outline possible future directions for exploration; with further deliberation, more elegant criteria may yet be found.

DONS: Dynamic Optimized Neighbor Selection for smart blockchain networks

Blockchain (BC) systems mainly depend on the consistent state of the Distributed Ledger (DL) at different logical and physical places of the network. The majority of network nodes need to be enforced to use one or both of the following approaches to remain consistent: (i) to wait for certain delays (i.e. by requesting a hard puzzle solution as in PoW and PoUW, or to wait for random delays as in PoET, etc.) (ii) to propagate shared data through shortest possible paths within the network. The first approach may cause higher energy consumption and/or lower throughput rates if not optimized, and in many cases these features are conventionally fixed. Therefore, it is preferred to enhance the second approach with some optimization. Previous works for this approach have the following drawbacks: they may violate the identity privacy of miners, only locally optimize the Neighbor Selection method (NS), do not consider the dynamicity of the network, or require the nodes to know the precise size of the network at all times. In this paper, we address these issues by proposing a Dynamic and Optimized NS protocol called DONS, using a novel privacy-aware leader election within the public BC called AnoLE, where the leader anonymously solves the The Minimum Spanning Tree problem (MST) of the network in polynomial time. Consequently, miners are informed about the optimum NS according to the current state of network topology. We analytically evaluate the complexity, the security and the privacy of the proposed protocols against state-of-the-art MST solutions for DLs and well known attacks. Additionally, we experimentally show that the proposed protocols outperform state-of-the-art NS solutions for public BCs. Our evaluation shows that the proposed DONS and AnoLE protocols are secure, private, and they acutely outperform all current NS solutions in terms of block finality and fidelity.

Perseverance in solving Sudoku: role of grit and cognitive flexibility in problem solving

ABSTRACTProblem solving is a higher order cognitive capacity with implications for everyday functioning. Although Grit predicts academic outcomes, the relation between facets of Grit, Consistency and Perseverance, and problem solving remain unknown. We report the results of two studies conducted to examine the impact of facets of grit on problem solving within the context of solving Sudoku puzzles. In Study 1, Grit-Perseverance predicted performance on the hard versus easy puzzle. In Study 2, we increased the difficulty level of the puzzles and assessed cognitive flexibility using the Wisconsin Card Sort Test. Grit-Perseverance was associated with effort on both the hard and very hard puzzles. Further, mediation analyses revealed that Grit-Perseverance indirectly predicted increased effort on the very hard puzzle through decreased cognitive flexibility. Overall our results demonstrate that Grit-Perseverance, not Consistency, impacts problem solving and highly gritty individuals may be most successful in solving challenging problems that are moderately constrained.

Landfill site selection in Makkah using geographic information system and analytical hierarchy process.

Municipal solid waste is a problem to developed and developing cities in the world. If municipal solid waste is not managed well, it can be a source of numerous contaminants to water, air, and soil. Although landfill is at the bottom in terms of priorities of municipal solid waste management techniques, its applicability cannot be neglected in developing economies. Landfill site selection is a hard puzzle comprised of political, social, economic, and environmental factors. Makkah, Saudi Arabia, is targeting 30 million pilgrims by 2030, putting the city in a difficult circumstance: More pilgrims, more municipal solid waste. The current dump site, Kakia, is expected to be full by 2020; thus, there is a need to locate a new landfill site. In 20 years, Makkah is expected to produce 44 million tonnes of municipal solid waste, which requires approximately a 7.5 m × 5,874,000 square meter landfill capacity. In this study, a geographic information system, analytical hierarchy process, vertical electrical sounding, and ground-penetrating radar are applied to select the best new landfill site for Makkah. By combining these techniques, there are three suitable site locations: (39°36 ́38.45 ́ ́E: 21°18 ́26.46 ́ ́N), (39°37 ́54.07 ́ ́E: 21°19 ́35.25 ́ ́N), and (39°44 ́04.45 ́ ́E: 21°13 ́08.93 ́ ́N). These sites have a considerable depth to water table of 12 m. Therefore, the city of Makkah should use these findings to establish a sanitary landfill.

The Jigsaw Puzzle in the Lunchroom.

The Jigsaw Puzzle in the Lunchroom.

On Evaluating Human Problem Solving of Computationally Hard Problems

This article is concerned with how computer science, and more exactly computational complexity theory, can inform cognitive science. In particular, we suggest factors to be taken into account when investigating how people deal with computational hardness. This discussion will address the two upper levels of Marr’s Level Theory: the computational level and the algorithmic level. Our reasons for believing that humans indeed deal with hard cognitive functions are threefold: (1) Several computationally hard functions are suggested in the literature, e.g., in the areas of visual search, visual perception and analogical reasoning, linguistic processing, and decision making. (2) People appear to be attracted to computationally hard recreational puzzles and games. Examples of hard puzzles include Sudoku, Minesweeper, and the 15-Puzzle. (3) A number of research articles in the area of human problem solving suggest that humans are capable of solving hard computational problems, like the Euclidean Traveling Salesperson Problem, quickly and near-optimally. This article gives a brief introduction to some theories and foundations of complexity theory and motivates the use of computationally hard problems in human problem solving with a short survey of known results of human performance, a review of some computationally hard games and puzzles, and the connection between complexity theory and models of cognitive functions. We aim to illuminate the role that computer science, in particular complexity theory, can play in the study of human problem solving. Theoretical computer science can provide a wealth of interesting problems for human study, but it can also help to provide deep insight into these problems. In particular, we discuss the role that computer science can play when choosing computational problems for study and designing experiments to investigate human performance. Finally, we enumerate issues and pitfalls that can arise when choosing computationally hard problems as the subject of study, in turn motivating some interesting potential future lines of study. The pitfalls addressed include: choice of presentation and representation of problem instances, evaluation of problem comprehension, and the role of cognitive support in experiments. Our goal is not to exhaustively list all the ways in which these choices may impact experimental studies, but rather to provide a few simple examples in order to highlight possible pitfalls.

Collaborative Problem Solving in Five‐Year‐Old Children: Evidence of social facilitation and social loafing

Children’s problem solving while working by themselves or with a partner was investigated to explore whether young children are susceptible to social facilitation and social loafing. Five‐year‐olds were asked to complete easy or hard puzzles, either alone or with a partner. Half of the children were given instructions indicating that their performance would be evaluated and the other half were not. Children showed social facilitation, in that they performed better with a partner than when working alone under evaluation conditions, with the easy puzzle. Children also showed social loafing, in that performance with a partner was poorer when working under no evaluation than evaluation conditions, with the easy puzzle. Performance with the hard puzzle did not differ whether children worked alone or with a partner, but children working on the hard puzzle under no evaluation conditions performed better than those working under evaluation conditions. The findings suggest that evaluation affects children’s performance in group settings in different ways depending on task difficulty.

The puzzle-interlayer model: an approach to the analysis of tightly packed arrangements of hard particles

The small-angle scattering (SAS) structure functions are analyzed for an idealized, random two-phase system: a stationary arrangement of hard puzzle particles, separated by a relatively thin interspace, which can be approximated by an interlayer. The detailed shape of the interlayer is defined by the shape of the particles themselves: The starting point for producing these initial particles is a three-dimensional initial puzzle {P_0} in the state of tessellation. Its pieces, homogeneous particles of random shape, fit together filling the space. In a second step, an expanded puzzle {P_{\tau }} is constructed by translating the initial particles by a certain length \tau (relative to one another). The whole tightly packed particle arrangement depends on {P_0}. The interlayer region between the particles is a connected, homogeneous region. The SAS intensity of {P_{\tau }} depends on the parameter \tau and on the typical shape and size of the pieces of {P_0}. Chord length distributions (CLDs) are used in the description. The random shape of the pieces of {P_0} possesses a CLD 1. The CLD 2 of the intermediate spaces is approximated by that of an idealized layer of constant thickness \tau. The scattering of {P_{\tau}} results in terms of the CLDs of both phases. The approach can be applied to many types of {P_0}. Two initial tessellations of {P_0} are studied, a `dead leaves' tessellation produced by spherical primary grains and the Poisson plane mosaic.

Facilitation on a Response-Loaded Task by Changes in Task Difficulty

The relation between changes in problem difficulty and performance was extended from discrimination studies to a speeded skill task. Children were given repeated trials with easy and hard puzzle blocks. An intermediate number of changes in difficulty facilitated performance more than trial-to-trial change or no change. It was suggested that an optimal amount of change may vary with the type of task considered and that further work with various difficulty sequences and tasks seems warranted.

New or Little Known North American Trees. IV

Previous articleNext article FreeNew or Little Known North American Trees. IVCharles S. SargentCharles S. Sargent Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 33, Number 2Feb., 1902 Article DOIhttps://doi.org/10.1086/328201 Views: 21Total views on this site Citations: 1Citations are reported from Crossref Journal History This article was published in the Botanical Gazette (1876-1991), which is continued by International Journal of Plant Sciences (1992-present). PDF download Crossref reports the following articles citing this article:Joey Shaw, Randall L. Small Addressing the “hardest puzzle in American pomology:” Phylogeny of Prunus sect. Prunocerasus (Rosaceae) based on seven noncoding chloroplast DNA regions, American Journal of Botany 91, no.66 (Jun 2004): 985–996.https://doi.org/10.3732/ajb.91.6.985