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Path planning is an important part of UAV mission planning. The main purpose of this paper is to overcome the shortcomings of the standard particle swarm optimization (PSO) such as easy to fall into the local optimum, so that the improved PSO applied to the UAV path planning can enable the UAV to plan a better quality path.

Firstly, the adaptation function is formulated by comprehensively considering the performance constraints of the flight target as well as the UAV itself. Secondly, the standard PSO is improved, and the improved particle swarm optimization with multi-strategy fusion (MFIPSO) is proposed. The method introduces class sigmoid inertia weight, adaptively adjusts the learning factors and at the same time incorporates K-means clustering ideas and introduces the Cauchy perturbation factor. Finally, MFIPSO is applied to UAV path planning.

Simulation experiments are conducted in simple and complex scenarios, respectively, and the quality of the path is measured by the fitness value and straight line rate, and the experimental results show that MFIPSO enables the UAV to plan a path with better quality.

Aiming at the standard PSO is prone to problems such as premature convergence, MFIPSO is proposed, which introduces class sigmoid inertia weight and adaptively adjusts the learning factor, balancing the global search ability and local convergence ability of the algorithm. The idea of K-means clustering algorithm is also incorporated to reduce the complexity of the algorithm while maintaining the diversity of particle swarm. In addition, the Cauchy perturbation is used to avoid the algorithm from falling into local optimum. Finally, the adaptability function is formulated by comprehensively considering the performance constraints of the flight target as well as the UAV itself, which improves the accuracy of the evaluation model.

This paper aims to present a three-axis attitude tracking control law to solve the attitude maneuver of a flexible satellite in the presence of parameter uncertainties and external disturbance.

Based on the relative dynamic equation where the relative attitude is described by quaternion, a robust control law composed of a proportional derivative (PD) part plus a signum function is designed and only requires the measurement of attitude and angular velocity. Furthermore, the stability analysis of the proposed control law is given through a two-step proof technique.

Numerical simulation results demonstrate that fine convergence of the attitude and angular velocity error and low-level vibration of flexible appendages are obtained by the proposed controllers.

The controller with the structure of a PD term plus a switching function about a sliding variable has low computational complexity and does not need to measure the modal variables of elastic appendages, so it can be used in orbit without modification.

The globally asymptotic stability of the controller in the presence of model uncertainties and external disturbances is proven rigorously through a two-step proof technique.

Single-valued neutrosophic sets (SVNSs) are efficient models to address the complexity issues potentially with three components, namely indeterminacy, truthness and falsity. Taking advantage of SVNSs, this paper introduces some new aggregation operators (AOs) for information fusion of single-valued neutrosophic numbers (SVNNs) to meet multi-criteria group decision-making (MCGDM) challenges.

Einstein operators are well-known AOs for smooth approximation, and prioritized operators are suitable to take advantage of prioritized relationships among multiple criteria. Motivated by the features of these operators, new hybrid aggregation operators are proposed named as “single-valued neutrosophic Einstein prioritized weighted average (SVNEPWA) operator” and “single-valued neutrosophic Einstein prioritized weighted geometric (SVNEPWG) operators.” These hybrid aggregation operators are more efficient and reliable for information aggregation.

A robust approach for MCGDM problems is developed to take advantage of newly developed hybrid operators. The effectiveness of the proposed MCGDM method is demonstrated by numerical examples. Moreover, a comparative analysis and authenticity analysis of the suggested MCGDM approach with existing approaches are offered to examine the practicality, validity and superiority of the proposed operators.

The study reveals that by choosing a suitable AO as per the choice of the expert, it will provide a wide range of compromise solutions for the decision-maker.

The purposes of this study are to synthesize the current research findings reported in major hospitality and tourism journals and to discuss the knowledge gaps where additional research endeavors are needed.

A systematic review approach was adopted to analyze 67 research articles about online reviews that were published between January 2000 and July 2015 in seven major hospitality and tourism journals.

This study presents a thematic framework of online review research, which was advanced by integrating the interactions among quantitative evaluation features, verbal evaluation features, reputation features and social features of online reviews with important outcomes of consumer decision-making and business performance. The thematic framework helps researchers identify the areas in extant hospitality literature of online reviews and point out possible directions for future studies.

The systematic review approach has a qualitative nature, where relevant literature was interpreted based on the authors’ domain knowledge and expertise.

Practitioners can gain a comprehensive understanding of the dynamic relationships among the key influential factors in online reviews, as presented in the thematic framework of online review research. Accordingly, managers will be able to develop effective strategies to leverage the positive impacts of online reviews to the business outcomes.

This systematic review synthesizes the findings reported in most recent publications (January 2000-July 2015; also including “Online First” articles) in seven major hospitality and tourism journals and develops an integrated research framework, anchoring on four meta-research questions and showing the dynamic relationships among the key players/factors/themes in online review research. This framework provides a visual diagram to practitioners for a better understanding of the relevant literature and assists researchers in developing new research questions for future studies.

Companies are adopting a more active role in managing their online reputations by using electronic word of mouth (eWOM) and often responding directly to customer reviews. Therefore, companies need to understand the effects of management responses to customer reviews. This study aims to explore whether it is worth responding to reviews and whether expressing gratitude enhances the effects of review responses.

This study uses customer reviews and management response data from a sample of 766 Spanish rural lodging establishments listed on Toprural (www.toprural.com). Analyses are undertaken with NVivo and SmartPLS.

Responding to negative reviews improves lodging establishments’ average ratings, but responding to positive reviews has no significant direct effect. Expressing gratitude in responses positively moderates the effects of review responses; this moderating effect is more significant for responses to negative than to positive reviews.

Previous research provides contradictory evidence about the positive outcomes of a company’s responses; it also does not address expressions of gratitude. This research provides evidence of the direct effects of management response quantity on ratings. It also expands current research on the content characteristics of these responses. The contextual setting for this research, rural tourism, is a key driver of sustainable rural development and a sector in which eWOM is especially relevant; thus, correctly managing the eWOM phenomenon becomes crucial.

Al objeto de mejorar su reputación online, las empresas progresivamente están adoptando un papel más activo ante las reseñas online de los clientes, ofreciendo respuestas online a dichas reseñas. Por tanto, es necesario que las empresas conozcan mejor los efectos de responder online. Este estudio examina si resulta beneficioso responder a las reseñas y si expresar agradecimiento potencia el efecto de responder.

A partir de datos sobre reseñas online de clientes y respuestas de la empresa, correspondientes a una muestra de 766 alojamientos de turismo rural de Toprural (www.toprural.com), se realizan análisis con NVivo y SmartPLS.

Responder a reseñas negativas mejora las puntuaciones medias del establecimiento en Toprural. Sin embargo, responder a reseñas positivas no tiene un efecto directo significativo. Además, expresar agradecimiento en las respuestas modera positivamente el efecto de responder. No obstante, esta moderación es más intensa en el caso de respuestas a reseñas negativas frente a las reseñas positivas.

La investigación previa aporta evidencia contradictoria sobre los efectos de la intensidad de respuesta empresarial a las reseñas online; además, no se ocupa de la expresión de gratitud en particular. Este estudio aporta luz respecto al efecto directo de la intensidad de respuesta sobre las puntuaciones online y amplía la investigación actual sobre las características de contenido de las respuestas. El marco de estudio, el turismo rural, se considera clave para un desarrollo rural sostenible y constituye un escenario donde el boca-oído electrónico es especialmente importante; en consecuencia, gestionar correctamente el fenómeno es crucial.

Palabras clave Boca-oído electrónico, Respuesta empresarial, Reputación online, Turismo rural

Tipo de artículo Trabajo de investigación

Continuous fiber reinforced thermoplastic composites (CFRTPCs) with great mechanical properties and green recyclability have been widely used in aerospace, transportation, sports and leisure products, etc. However, the conventional molding technologies of CFRTPCs, with high cost and low efficiency, limit the property design and broad application of composite materials. The purpose of this paper is to study the effect of the 3D printing process on the integrated rapid manufacturing of CFRTPCs.

Tensile and flexural simulations and tests were performed on CFRTPCs. The effect of key process parameters on mechanical properties and molding qualities was evaluated individually and mutually to optimize the printing process. The micro morphologies of tensile and flexural breakages of the printed CFRTPCs were observed and analyzed to study the failure mechanism.

The results proved that the suitable process parameters for great printing qualities and mechanical properties included the glass hot bed with the microporous and solid glue coatings at 60°C and the nozzle temperature at 295°C. The best parameters of the nozzle temperature, layer thickness, feed rate and printing speed for the best elastic modulus and tensile strength were 285°C, 0.5 mm, 6.5r/min and 500 mm/min, respectively, whereas those for the smallest sectional porosity were 305°C, 0.6 mm, 5.5r/min and 550 mm/min, respectively.

This work promises a significant contribution to the improvement of the printing quality and mechanical properties of 3D printed CFRTPCs parts by the optimization of 3D printing processes.

Happiness is an important mental emotion and yet becoming a major health concern nowadays. For this reason, better recognizing the objective understanding of how humans respond to event-related observations in their daily lives is especially important.

This paper uses non-intrusive technology (hyperspectral imaging [HSI]) for happiness recognition. Experimental setup is conducted for data collection in real-life environments where observers are showing spontaneous expressions of emotions (calm, happy, unhappy: angry) during the experimental process. Based on facial imaging captured from HSI, this work collects our emotional database defined as SWU Happiness DB and studies whether the physiological signal (i.e. tissue oxygen saturation [StO2], obtained by an optical absorption model) can be used to recognize observer happiness automatically. It proposes a novel method to capture local dynamic patterns (LDP) in facial regions, introducing local variations in facial StO₂ to fully use physiological characteristics with regard to hyperspectral patterns. Further, it applies a linear discriminant analysis-based support vector machine to recognize happiness patterns.

The results show that the best classification accuracy is 97.89 per cent, objectively demonstrating a feasible application of LDP features on happiness recognition.

This paper proposes a novel feature (i.e. LDP) to represent the local variations in facial StO₂ for modeling the active happiness. It provides a possible extension to the promising practical application.

Previous studies have reported that dietary fibers such as polydextrose and maltodextrin can reduce food intake; however, the studies on the differences of this effect are insufficient. The purpose of this paper is to compare the effects of dietary fibers maltodextrin and polydextrose on alterations of short-term satiety, energy intake and postprandial blood glucose in healthy females.

This study was designed as a randomized, crossover and double blind research. For this purpose, 21 healthy females consumed a milkshake containing 0 g (control), 15 g polydextrose (PDX) and 15 g maltodextrin (MDX), and an ad libitum lunch meal was served 150 min later. Subjective appetite scores (hunger, satiety, prospective food consumption and desire to eat) were measured using a visual analog scale. Appetite scores and blood glucose were measured before preload and once per 15 min after milkshake consumption.

Visual analog scale scores showed that PDX had an improved effect on satiety and hunger feelings. Compared to the control, dietary fiber increased the Area Under Curve (AUC) scores of satiety (p < 0.001) and decreased the AUC scores of hunger (p < 0.001), prospective food consumption (p < 0.001) and desire to eat (p < 0.001). Energy intake during ad libitum meal was significantly lower in PDX (Control: 862 (54.3) Kcal versus PDX: 679 (35.4) Kcal and MDX: 780 (49.3) Kcal. Moreover, the blood glucose levels were significantly lower in MDX.

This study conducted with healthy females demonstrated that PDX was more effective in inducing satiety during subsequent food intake, and that postprandial blood glucose were within more healthy levels in MDX.

This study aims to develop a bimodal nano-silver paste with improved mechanical property and reliability. Silicon carbide (SiC) particles coated with Ag were introduced in nano-silver paste to improve bonding strength between SiC and Ag particles and enhance high-temperature stability of bimodal nano-silver paste. The effect of sintering parameters such as sintering temperature, sintering time and the proportion of SiC particles on mechanical property and reliability of sintered bimodal nano-silver structure were investigated.

Sandwich structures consist of dummy chips and copper substrates with nickel and silver coating bonded by nano-silver paste were designed for shear testing. Shear strength testing was conducted to study the influence of SiC particles proportions on the mechanical property of sintered nano-silver joints. The reliability of the bimodal nano-silver paste was evaluated experimentally by means of shear test for samples subjected to thermal aging test at 150°C and humidity and temperature testing at 85°C and 85 per cent RH, respectively.

Shear strength was enhanced obviously with the increase of sintering temperature and sintering time. The maximum shear strength was achieved for nano-silver paste sintered at 260°C for 10 min. There was a negative correlation between the proportion of SiC particles and shear strength. After thermal aging testing and humidity and temperature testing for 240 h, the shear strength decreased a little. High-temperature stability and high-hydrothermal stability were improved by the addition of SiC particles.

Submicron-scale SiC particles coated with Ag were used as alternative materials to replace part of nano-silver particles to prepare bimodal nano-silver paste due to its high thermal conductivity and excellent mechanical property.

The purpose of this paper is to elucidate the influences of the animal fat and fatty acid type on the formation of polycyclic aromatic hydrocarbons (PAHs) and to propose a formation mechanism of PAHs in fat during electric roasting, which is a method of non-direct-contact-flame heating.

The effects of animal fats and model fat on the formation of PAHs were valued on the basis of the ultra high-performance liquid chromatography data. The corresponding products of the FAME pyrolysis were detected by TG-FTIR. The proposal formation mechanism of PAHs was based on the summary of the literature.

Contrary to the International Agency for Research on Cancer, DF had higher risk with 280.53 ng/g of concentration after being roasted than the others animal fats of red meat in terms of PAHs formation. This research also ensured the importance of fat on PAHs formation, the concentration of PAHs in pure fats was higher after being electric roasted than that in meat patties and juice which made from corresponding animal fat. What is more, during pure animal fats and meat products being processed, less PAHs formed in the fat with lower extent of unsaturation and lower content of linolenate. In the same way, methyl linolenate demonstrated the significant increasement to PAHs formation compared to the other fatty acids. And, the number of carbon atom and the extent of unsaturation in fatty acid affects the formation of PAHs during roasting. The detection of alkene and alkane allows to propose a formation mechanism of PAHs during model fat being heated. Further study is required to elucidate the confirm moleculars during the formation of PAHs.

This work studied the effect of the carbon atom number and the unsaturation extent of fats and model fats on the formation of PAHs. This work also assure the important of alkene and alkane on the pyrolysis of model fats. This study also researched the formation and distribution of PAHs in pure fats and meat products after being heated.