Namnabat et al. (cf., [Carbon Letters, https://doi.org/10.1007/s42823-020-00194-2]) employ the classical approach of Li and Chou (cf., [Int J Solids Struct 40: 2487–2499]) to the implementation of the molecular structural mechanics method using the Bernoulli–Euler beam elements for nonlinear buckling analysis of double-layered graphene nanoribbons. However, more recent studies by Eberhardt and Wallmersperger (cf., [Carbon 95: 166–180]) and others (see, e.g., [Int J Eng Sci 133: 109–131]) have shown that the classical approach of Li and Chou poorly reproduces both in-plane and out-of-plane mechanical moduli of graphene. We have shown that the 2D beam-based hexagonal material used by Namnabat et al. poorly simulates the mechanical moduli of graphene, especially the bending rigidity modulus, and this material cannot be used for the buckling simulation of graphene sheets (or nanoribbons). In addition, it is noted that in Int J Eng Sci 133: 109–131, a modification of the classical approach of Li and Chou is given which exactly reproduces both in-plane (2D Young’s modulus and Poisson’s ratio) and out-of-plane (bending rigidity modulus) mechanical moduli of graphene using beam elements.

Double-layer graphene nanoribbons promise potential application in nanoelectromechanical systems and optoelectronic devices, and knowledge about mechanical stability is a crucial parameter to flourish the application of these materials at the next generation of nanodevices. In this paper, molecular mechanics is utilized to investigate nonlinear buckling behavior, critical buckling stress, and lateral deflection of double-layered graphene nanoribbons under various configurations of stacking mode and chirality. The implicit arc-length iterative method (modified Riks method) with Ramm’s algorithm is utilized to analyze the nonlinear structural stability problem. The covalent bonds are modeled using three-dimensional beam elements in which elastic moduli are calculated based on molecular structural mechanics technique, and the interlayer van der Waals (vdW) interactions are modeled with nonlinear truss elements. An analytical expression for Young’s modulus of nonlinear truss elements is derived based on the Lennard–Jones potential function and implemented in numerical simulation with a UMAT subroutine based on FORTRAN code to capture the nonlinearity of the vdW interactions during the buckling analysis. The results indicate that the highest critical buckling stress and the minimum lateral deflection occur for armchair and zigzag chirality, both with AB stacking mode, respectively. Moreover, the critical buckling stress is found to be directly dependent on the mode shape number regardless of in-phase or anti-phase deflection direction of layers. Lateral deflection exhibits a similar trend with mode shape in anti-phase mode; however, it is decreasing by increasing mode shape number in in-phase mode.

Social games where players play together with others in multiplayer mode are currently emerging and attracting attention in the media after the success of e.g. Pokemon GO. Nevertheless, little is known about the profitability of social players. Previous gaming research that has profiled different types of players has focused on games played alone, without social mechanics (cf. Vahlo et al., 2017). From a marketing perspective, it is also interesting to study the effects of merely watching game play or browsing new game ads as a mode of entertainment, and what kind of effect that has on future behaviour. Passive participation as a type of aesthetic entertainment has been acknowledged in eSports context (Seo, 2013). This paper analyses big data of a gaming company on an individual player level, including different types of single play and multiplayer gaming sessions and in-game purchase behaviour data. We compare the effects of social and non-social ingame mechanics on how individuals spend money in-game over time, frequency of play, sessions as well as the length of played sessions in minutes during the gamers’ whole lifecycle. The anonymized repository data includes gaming behaviour, in-game purchase behaviour related to the use of one specific digital game in the USA. The game can be played both alone, and with others as a team. We used structural equation modeling to analyse the behavior of 23 049 randomly selected players, who have played the game for at least one week. The data included the individual players’ total session history during their play lifecycle. Interestingly, social play with other people is a strong predictor of money spent in the long term. Social play also prompts long-term interest in the game, as friends invite and encourage each other to play with or against other virtual teams. Nevertheless, social play is not for everyone! The results help to optimize player journeys and to make strategic decisions that support long term profitability of gaming companies.

본 연구에서는 정치관련 이슈정보에 대해 기초적인 게임메커닉스를 활용하여 정치인(정당)을 평가하는 블 록제인 기반의 게이미피케이션 시스템과 방법을 제안하고자 한다. 게이미피케이션은 플레이어들의 자발적 참여와 문제해결을 위해 게임적사고와 게임메커닉스(순위표, 점수, 단계, 가상증표, 아이템 등)를 적용하는 개념 이다. 게이미피케이션 연구에서 '플레이어'는 사용자, 관객, 고객, 손님, 구매자, 학습자, 환자, 군인 등을 포괄하므로, 이 논문에서 플레이어는 유권자(혹은 투표자)를 말하고, 이 표현들은 같은 의미로 병기하였다. 게이미피 케이션의 이론배경은 '게임요소'나 MDA프레임워크(게임메커닉스,게임역학,게임미학) 등의 '게임학 연구'를 기반 으로 한다. 이 논문에서는 효율적인 연구를 위해, 우선 기초적인 게임메커닉스만을 정치인(정당)의 성공적인 평가 시스템에 적용하였다. 정치인(정당) 평가에 게이미피케이션를 적용하려는 주목적은, 유권자(투표자)의 자 발적 정치참여를 독려하기 위함이며, 이 논문에서 제안하는 시스템과 방법이 적용된 이슈정보는 더 유익한 플 레이어 경험(PX) 창출에 도움을 줄 것이다. 끝으로, 본 정치 평가 인터렉티브 게임화 시스템과 방법 연구는, 보 안에 취약할 수밖에 없는 웹 또는 앱서비스의 한계를 보완하고자 블록체인을 기반으로 신뢰도를 높이고자 하였다.

This paper is to show how electronic game components can galvanize into the outdated regions. The purpose of this study is to research on game mechanics and PX(player experience) for the interactive urban regeneration design with gamification. Urban regeneration involves the old public, private and community sectors to improve the quality of urban life and to reach a sustainable development of urban economic. The gamification is the idea of using game-thinking and game mechanics to solve problem and engage players, so theoretical background of gamification is based on game design studies such as game components and MDA framework which consists of mechanics, dynamics, and aesthetics. Most of researchers regard game mechanics as game components and converse, but game mechanics is representative of these two terms. So this paper treats game mechanics as the first effective factor for successful urban renewal. Such games which have huge fans bring the powerful and manipulated user experience, a well-gamified applications can provide players (stand for users, audiences, customers, clients, buyers, learners, patients, soldiers, etc) with the supreme user experience, aka PX(player experience) causing playful behavior and a positive mindset. The main goal of gamification of urban regeneration is to encourage greater engagement in renewed town people(player) and aiding in creating richer experiences in everyday life events through game mechanics and PX. Also this paper shows tens of gamification ideas for interactive urban revitalization.

In this paper, we proposed some direction to effective development of gamification. To achieve this purpose, we performed an extensive literature review. Based on game mechanics and game dynamics, we analyzed 145 cases for both domestic sites(15 cases) and international sites(130 cases) by keyword search methods. Results showed that the successful cases(n=32) applied more features of game mechanics and game dynamics in various ways. Through this, we tried to build up categorization of gamification, the major applications of gamification can be converged into five primary areas: public policy, medical welfare, education, environmental protection and corporation. Finally, we discussed about implications of using gamification for future direction.

This study carried out finite element deflection analysis of cylindrical shell structures made of composite materials, which is based on the micro-mechanical approach for different fiber-volume fractions. The finite element (FE) models for composite structures using multi-scale approaches described in this paper is attractive not only because it shows excellent accuracy in analysis but also it shows the effect of the material combination. New results reported in this paper are focused on the significant effects of the fiber-volume fraction for various parameters, such as fiber angles, layup sequences, and length-thickness ratios. It may be concluded from this study that the combination effect of fiber and matrix, largely governing the dynamic characteristics of composite shell structures, should not be neglected and thus the optimal combination could be used to design such civil structures for better dynamic performance.

An energy based crack growth model is developed in this study to simulate the propagation of top-down cracking in asphalt pavements. A viscoelastic fracture mechanics approach, generalized J integral, is employed to model the crack growth of asphalt concrete. Laboratory fatigue crack propagation tests for three different asphalt mixtures are performed at various load levels, frequencies and temperatures. Disk-shaped specimens with a proper loading fixture and crack growth monitoring system are selected for the tests. It is observed from the tests that the crack propagation model based on the generalized J integral is independent of load levels and frequencies, while the traditional Paris’ law model based on stress intensity factor is dependent of loading frequencies. However, both models are unable to take care of the temperature dependence of the mixtures. The fatigue crack propagation model proposed in this study has a good agreement between experimental and predicted crack growth lives, which implies that the energy based J integral could be a better parameter to describe fatigue crack propagation of viscoelastic materials such as asphalt mixtures.

본 논문에서는 다중 균열 구조물에서의 균열 진전에 따른 에너지 해방을 및 고차 미분값을 구할 수 있는 가상균열 진전법을 제시한다. 이 방법은 다중 균열 체계의 에너지 해방율과 고차 미분값이 단 한번의 해석으로 수행될 수 있는 장점이 있다. 예제에서 얻어진 해의 최대 오차는 에너지 해방율 0.2%, 일차 미분값이차 미분값 이다 이 방법으로 구한 에너지 해방률의 미분값들은 파괴 확률을 구하거나, sire effect law에 적용될 수 있다.

본 연구에서는 미분 가능한 함수가 Taylor 전개로 표현되고 그 계수들은 주어진 함수와 미분에 대한 근사값을 제공할 수 있다는 점에 착안하여 m차 Taylor 다항식을 구성하고 이동최소제곱법을 이용하여 그 계수들을 구했다. 계산된 근사함수와 미분을 콜로케이션 개념을 바탕으로 균열 문제를 포함하는 고체문제에 대한 지배 미분방정식에 적용하여 차분식 형태의 이산화된 계방정식을 구성하였다. 본 연구의 해석기법은 격자망(grid)에 의존적이고 근사함수가 없는 유한차분법과 형상함수의 미분과 약형식의 적분산정, 필수경계조건 처리가 어려운 Galerkin법 기반의 무요소법의 단점을 효과적으로 극복한 새로운 수치기법이다.

용접접합부 균열의 파괴역학적 해석을 위해서는 용접중에 발생하는 잔류응력해석과 파괴해석이 병행되어야 한다. 잔류응력이 존재하면 J-적분은 더 이상 적분경고에 관계없이 인정한 값을 갖는 특성을 잃어버리게 된다. 또한 균질한 재료와는 달리 이종재료 계면균열에서는 균열선난에서 Mode I과 Mode II의 파괴거동이 동시에 발생한다. 그러므로 이종강재 용접접합부 균열의 J-적분 해석을 위해서는 이종강재 용접시 발생하는 잔류응력이 존재하는 경우에도 적분경로에 관계없이 일정한 값을 갖는 새로운 J-적분식이 도입되어야 한다. 따라서 본 연구에서는 기존의 J-적분을 수정하여, 이종강재 용접시 발생하는 잔류응력이 존재하는 경우에 경로 독립성을 유지하는 J-적분을 고찰하고, 이를 이용하여 잔류응력과 외력이 동시에 작용하는 균열선단에서의 J-적분을 해석할 수 있는 프로그램을 개발하였다. 자체개발한 탄소성 해석프로그램을 이용하여 이종강재 용접시 잔류응력과 외력에 대한 응력분포를 계산하였으며, 이를 이용하여 잔류응력과 외력의 복합하중에 대한 J-적분을 계산하였다.