Effects of local minima and bifurcation delay on combinatorial optimization with continuous variables

Combinatorial optimization problems can be mapped onto Ising models, and their ground state is generally difficult to find. A lot of heuristics for these problems have been proposed, and one promising approach is to use continuous variables. In recent years, one such algorithm has been implemented by using parametric oscillators known as coherent Ising machines. Although these algorithms have been confirmed to have high performance through many experiments, unlike other familiar algorithms such as simulated annealing, their computational ability has not been fully investigated. In this paper, we propose a simple heuristic based on continuous variables whose static and dynamical properties are easy to investigate. Through the analyses of the proposed algorithm, we find that many local minima in the early stage of the optimization and bifurcation delay reduce its performance in a certain class of Ising models.Comment: 12 pages, 10 figure

Noncontact brain-computer interface based on steady-state pupil light reflex using independent bilateral eyes stimulation

Steady-state visual evoked potential (SSVEP), which uses blinking light stimulation to estimate the attending target, has been known as a communication technique with severe motor disabilities such as ALS and Locked-in-syndrome. Recently, it was reported that pupil diameter vibration based on pupillary light reflex has been observed in the attending target with a constant blinking frequency. This fact suggests the possibility of a noncontact BCI using pupillometers as alternatives to contacting scalp electrodes. In this study, we show an increment in the number of communication channels by stimulating both eyes alone or in combination with different frequencies. The number of selective targets becomes twice the number of frequencies using this method. Experiments are conducted by recruiting three healthy participants. We prepare six target patterns comprising three frequencies and detect the target using a coefficient of correlation of power spectrum between the pupil diameter and stimulus signal. Consequently, the average classification accuracy of the three participants of approximately 83.4% is achieved. The findings of this study demonstrate the feasibility of noncontact BCI systems

Service Chain Provisioning Model Considering Traffic Changes Due to Virtualized Network Functions

Service chaining provides network services by flexibly configuring service chains that connect virtualized network functions (VNFs) in the appropriate order so as to satisfy users’ needs. Existing models can be inefficient in terms of consuming network and computation resources since the models do not consider the traffic changes due to VNFs or the models restrict routing and VNF placement. This paper proposes a service chain provisioning model that handles the traffic changes created by VNFs while determining the VNF visit order of each request, request routes, and VNF placement. The service chain provisioning problem is formulated as an integer linear programming (ILP) problem. Three methods for limiting the number of VNF visit order patterns considered in the ILP problem are introduced to shorten the computation time. In order to handle a problem that is intractable with the ILP model, we introduce a greedy algorithm and an algorithm that divides the problem into the VNF placement part and the routing part. Numerical results show that considering the traffic changes due to VNFs yields more efficient consumption of network and computation resources than the alternative of assuming that the traffic amount of each request is constant between the endpoints. The results also show that the computation time can be shortened in our examined scenarios while we obtain the objective value larger by at most 0.4% than the optimal value by limiting the number of visit order patterns considered

Branding (marca) de atleta em esporte menos popular: uma abordagem triádica

Objective of the study: Despite the opportunities to develop athlete brands, many athletes in less popular sport still struggle with developing their brands. Therefore, the current study aimed to contribute to the existing athlete branding literature and practitioners by providing a better and holistic understanding of athlete branding in less popular sport.Methodology: The current we employed a triadic approach that was involved with three stakeholders:  Athlete, fans, and media to explore important factors in athlete branding strategies in less popular sport.Originality/ Relevance: There is less focus on less popular sport and their stakeholders branding. With increasing interest from fans less popular sport and their athletes are gaining more attention than ever. Thus, the study opted to discuss an ignored phenomenon in the context of athlete branding.    Main results: The result of the study identified four main themes and eight associated subthemes based on both the interview and media content analysis. These main and subthemes include (1) performance (on-field success, competition level), (2) personal/private (off-field characteristics, impression management), (3) business/marketing (athlete promotion, merchandized products), and (4) contextual factor (sport nature, proximity).Theoretical / methodological contributions current study contributed in the existing literature of athlete branding via focusing a top athlete of less popular sport.Objetivo del estudio: A pesar de la existencia de oportunidades para desarrollar marcas de deportistas, en deportes menos populares, los deportistas encuentran dificultades en este tema. Por lo tanto, el presente estudio tuvo como objetivo contribuir a la literatura existente sobre la marca del deportista, proporcionando una comprensión mejor y holística de la marca del deportista en los deportes menos populares..Metodología: Empleamos lo enfoque triádico que involucró a tres partes interesadas: atleta, fans y medios de comunicación para explorar factores importantes en las estrategias de marca de atleta en deportes menos populares.Originalidad/Relevancia: Hay menos enfoque en los deportes menos populares y la marca de sus partes interesadas. Con el creciente interés de los fanáticos del deporte menos popular y sus atletas, están ganando más atención que nunca. Por lo tanto, el estudio optó por discutir un fenómeno ignorado en el contexto de la marca de los atletas.Resultados principales: Los resultados identificaron cuatro temas principales y ocho subtemas asociados basados en entrevistas y análisis de contenido de los medios. Estos temas principales y subtemas incluyen (1) rendimiento (éxito deportivo, nivel de competencia), (2) personal / privado (características no deportivas, gestión de imagen), (3) negocios / marketing (promoción de atletas, productos de marketing) y (4) factor contextual (carácter deportivo, proximidad).Contribuciones teóricas / metodológicas: El estudio actual contribuyó a la literatura existente sobre la marca de atletas al enfocarse en un atleta de élite de un deporte menos popular.Objetivo do estudo: Apesar da existência de oportunidades de desenvolvimento de marcas dos atletas, em esportes menos populares os atletas encontram dificuldades neste tema. Portanto, o presente estudo teve como objetivo contribuir com a literatura existente sobre a marca do atleta, fornecendo uma compreensão melhor e holística da marca do atleta em esportes menos populares.Metodologia: Empregamos a abordagem triádica que envolveu três partes interessadas: Atleta, fãs e mídia, para explorar fatores importantes nas estratégias de marca do atleta em esportes menos populares..Originalidade/Relevância: Há menos foco no esporte menos popular e na marca de seus stakeholders. Com o crescente interesse dos fãs por esportes menos populares e seus atletas estão ganhando mais atenção do que nunca. Assim, o estudo optou por discutir um fenômeno ignorado no contexto da marca do atleta.Principais resultados: Os resultados identificaram quatro temas principais e oito subtemas associados com base nas entrevistas e na análise de conteúdo da mídia. Esses principais e subtemas incluem (1) desempenho (sucesso esportivo, nível de competição), (2) pessoal / privado (características fora do esporte, gerenciamento de imagem), (3) negócios / marketing (promoção de atleta, produtos mercadológicos) e (4) fator contextual (natureza esportiva, proximidade).Contribuições teóricas/metodológicas: o estudo atual contribuiu na literatura existente sobre a marca do atleta por meio do foco em um atleta importante de um esporte menos popular

A Practical and Scalable Decoder for Topological Quantum Error Correction with Digital Annealer

Quantum error correction is one of the most important milestones for realization of large-scale quantum computation. To achieve this, it is essential not only to integrate a large number of qubits with high fidelity, but also to build a scalable classical system that can perform error correction. Here, we propose an efficient and scalable decoder for quantum error correction using Fujitsu Digital Annealer (DA). Specifically, the error correction problem of stabilizer codes is mapped into an Ising-type optimization problem, so-called quadratic unconstrained binary optimization (QUBO) problem, which is solved by DA. In particular, we implement the proposed DA decoder for the surface code and perform detailed numerical experiments for various code distances to see its performance and scalability. We observe that computational scaling for the DA decoder has a lower order of polynomial than the decoding methods using simulated annealing (SA) and minimum-weight perfect matching (MWPM) algorithm under all tested conditions. Furthermore, the threshold behavior of the logical error probability for the DA decoder is analyzed and the resultant threshold value is about 9.7% which is very close to that obtained by the MWPM decoder. This result clearly shows the high potential of the DA decoder for quantum error correction.Comment: 10 pages, 11 figure

Quantum hydrodynamics from local thermal pure states

We provide a pure state formulation for hydrodynamic dynamics of isolated quantum many-body systems. A pure state describing quantum systems in local thermal equilibrium is constructed, which we call a local thermal pure quantum ($\ell$TPQ) state. We show that the thermodynamic functional and the expectation values of local operators (including a real-time correlation function) calculated from the $\ell$TPQ state converge to those from a local Gibbs ensemble in the large fluid-cell limit. As a numerical demonstration, we investigate a one-dimensional spin chain and observe the hydrodynamic relaxation obeying the Fourier's law. We further prove the second law of thermodynamics and the quantum fluctuation theorem, which are also validated numerically. The $\ell$TPQ formulation gives a useful theoretical basis to describe the emergent hydrodynamic behavior of quantum many-body systems furnished with a numerical efficiency, being applicable to both the non-relativistic and relativistic regimes.Comment: 7 pages, 3 figures (+11 page, 8 figures supplemental material); (v2) references adde

Examining the Youth Multi-Sport Event Environment: Implications towards athlete development and transitioning.

Many factors are associated with a person’s attitude formation and intention towards a behavior. In this study, we examined organizational factors that helped form young athletes attitudes regarding their future plans in high performance sport. Through a mixed method survey design, data was collected from 207 young pre-elite athletes who competed during the 2017 Commonwealth Youth Games in Bahamas. Several organizationally controlled aspects of the games environment were found to contribute to young athlete’s satisfaction with the event including their accommodations, available information regarding their sport and finally, the social and cultural activities during games-time. However, satisfaction with the games environment was not predictive of young athletes future intentions to remain in sport. Qualitative thematic coding denoted two key themes related to athlete plans to continue in high performance sport: level of satisfaction and learning. Further, qualitative results revealed five main impediments to continuing in high performance sport specifically, physiological, psychological, performance, environment and life concerns. The paper contributes to our understanding of the controllable and uncontrollable social and environmental factors in a multi-sport international event. Nationally controlled factors that influence young athletes attitude formation, specifically their satisfaction and intentions to remain in sport

The effect of Rugby World Cup 2019 on residents’ psychological well-being: a mediating role of psychological capital

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. The current study aimed to examine the relationships among residents’ impact perception of 2019 Rugby World Cup (i.e. economic impact, cultural interests and new opportunity, community pride, and environmental impact), psychological capital (i.e. hope, self-efficacy, optimism, and resilience), and psychological well-being. The two-wave time-lagged data were collected from residents in the host cities (a following week of the event and eight weeks after the event; N = 206). The results indicated that residents’ perceptions of event impacts were positively associated with psychological capital, which influenced psychological well-being over time. Cultural interests and community pride were considered particularly influential in enhancing residents’ psychological well-being. The findings are useful for policy makers, planning to utilize mega events to boost residents’ psychological well-being