Search results

The purpose of this paper is to develop lightweight actuators in order to replace conventional hydraulic/pneumatic actuators and to apply the actuation system to a small flying vehicle.

A new type of control surface using a piezo‐composite actuator for a small flying vehicle has been designed and manufactured. The piezo‐composite actuator is composed of a piezoelectric ceramic layer, a carbon/epoxy layer and glass/epoxy layers. Through this, the miniaturization and weight reduction of the actuation systems for flying vehicle can be achieved. A simple model of the control surface has been manufactured and evaluated through experiments.

The performance test results showed that the developed actuator can produce stable angle of attack independent of the applied loading. A radio controller for the actuator was developed to control the motions wirelessly. It was found that the piezo‐composite actuator and its integrated controller system have a possibility to be used not only as a small flying vehicle but also as a control surface actuator of a small unmanned flying robot through the miniaturization of power supply and control system.

The paper describes the procedures of designing and manufacturing smart structure application of the piezo‐composite actuator with performance evaluation and comparison method. It is expected that piezo‐composite actuator can be used as a small flying vehicle control surface actuator through the miniaturization of power supply and control system with the use of the integrated radio controller MIPAD.

The purpose of this paper is to demonstrate the uncontrolled vertical takeoff of an insect-mimicking flapping-wing micro air vehicle (FW-MAV) of 12.5 cm wing span with a body weight of 7.36 g after installing batteries and power control.

The forces were measured using a load cell and estimated by the unsteady blade element theory (UBET), which is based on full three-dimensional wing kinematics. In addition, the mean aerodynamic force center (AC) was determined based on the UBET calculations using the measured wing kinematics.

The wing flapping frequency can reach to 43 Hz at the flapping angle of 150°. By flapping wings at a frequency of 34 Hz, the FW-MAV can produce enough thrust to over its own weight. For this condition, the difference between the estimated and average measured vertical forces was about 7.3 percent with respect to the estimated force. All parts for the FW-MAV were integrated such that the distance between the mean AC and the center of gravity is close to zero. In this manner, pitching moment generation was prevented to facilitate stable vertical takeoff. An uncontrolled takeoff test successfully demonstrated that the FW-MAV possesses initial pitching stability for takeoff.

This work has successfully demonstrated an insect-mimicking flapping-wing MAV that can stably takeoff with initial stability.

The purpose of this paper is to examine how corporate environmental management strategies at different environmental management maturity (EMM) stages are influenced by institutional forces in the service sector organizations of a developing country.

The authors used a multiple case study approach in this study. Institutional isomorphic pressures (coercive, mimetic and normative) at different EMM stages were used as the analytical framework.

The study finds coercive pressures largely shape the corporate environmental management strategies at the reactive stage while mimetic pressures have the greatest influence on the internal integration stage. Combined mimetic and normative pressures influence the environmental strategies at the external integration stage. Further, it emphasizes the importance of various institutional pressures in propelling the organizations in the developing countries to benefit from higher levels of EMM.

This paper offers a new theoretical approach that highlights the importance of considering the institutional influence of the top-down process of diffusion and simultaneous counter-process of invention by which the lower level organizational actors shape and change their environmental management practices for corporate EMM.

The purpose of this study is to develop the scale of the metaverse experience and examine the effect of the metaverse experience on consumer happiness in luxury brands.

A survey was distributed to metaverse users from general participants in the Republic of Korea. To reach this goal, the domain of the metaverse experience is defined, items are created through qualitative interviews, the initial scale is refined and then the scale is tested. A total of 262 valid responses were used for exploratory factor analysis (EFA), and 238 data were used for confirmatory factor analysis (CFA). The hypothesis was tested using structural equation modeling (SEM) and SmartPLS 3.0.

The results showed that the metaverse experience comprises three sub-constructs, namely fantasies, feelings and fun. Also, the metaverse experience affects consumer happiness positively in luxury brands.

This study investigates consumer experience in the metaverse environment. The authors examined the metaverse experience based on the experiential aspects of the consumption of luxury brands and develop the scale development of the metaverse experience. Furthermore, the relationship between metaverse experiences and consumer happiness provides a new perspective in studying metaverse marketing strategy and customer service creation.

The purpose of this study is to examine the influences of creativity, psychological ownership (PO) and perceived organizational support (POS) on knowledge creation, using the integrative systems model of creativity.

A survey was used to collect data from 188 workers in Korean public service organizations. Analyses, including bootstrapping and hierarchical regression analysis, were performed to determine the mediating effect of PO and also the moderating and the moderated mediating effects of POS.

The results showed that PO mediates partially between creativity and knowledge creation and that POS moderates the relationship between PO and knowledge creation. Notably, the moderated mediating effect of POS was only significant when employees had a high level of POS.

The findings suggest that creativity dissemination requires employees’ social consciousness, collaborative interactions and organizational support. The results imply that human resource development (HRD) practitioners need to cultivate the creativity capacity in the organization.

This study discusses the effects of PO and POS on creative performance, which HRD professionals and organizational leaders draw attention to for organizational development. Implications for organizational composition and interventions to enhance creative performance are provided.

This study examines the extreme quantile connectedness and spillovers between West Texas Intermediate (WTI) crude oil futures and ten Vietnamese stock market sectors. Knowledge of such links is important to both investors and policymakers in understanding the transmission of shocks across markets.

The authors employ the extreme quantile connectedness methodology of Ando et al. (2022).

Initial results show that the size of spillovers is higher during bearish markets than bullish markets and under major financial, political, energy and pandemic events. The oil market is a net receiver of spillovers during downward markets and net contributors during upward markets. The banking sector is a net contributor of spillovers, whereas consumer discretionary and consumer staples are net receivers for different quantiles. The role of the remaining sectors as net receivers/contributors is sensitive to the quantiles. Oil has a large spillover effect on the electricity sector for all quantiles. Comparing all crises, oil offers the best hedging effectiveness to the Vietnamese sector during the coronavirus disease 2019 (COVID-19) crisis. Moreover, oil was a cheap hedge asset during oil crises. Finally, oil provides the highest hedging effectiveness for healthcare during the global financial crisis (GFC) and consumer staples during the European debt crisis (EDC), oil crisis and COVID-19.

Acknowledging the presence of heterogeneity in the relation between oil and economic sectors under different market conditions, this study is the first to examine the extreme quantile connectedness between oil and Vietnamese sectors.

The purpose of this paper is to analyse the thermal environment of two engineering testing centres cooled via different means using computational fluid dynamics (CFD), focussing on the indoor temperature and air movement. This computational technique has been used in the analysis of thermal environment in buildings where the profiles of thermal comfort parameters, such as air temperature and velocity, are studied.

A pilot survey was conducted at two engineering testing centres – a passively cooled workshop and an air-conditioned laboratory. Electronic sensors were used in addition to building design documentation to collect the required information for the CFD model–based prediction of air temperature and velocity distribution patterns for the laboratory and workshop. In the models, both laboratory and workshop were presumed to be fully occupied. The predictions were then compared to empirical data that were obtained from field measurements. Operative temperature and predicted mean vote (PMV)–predicted percentage dissatisfied (PPD) indices were calculated in each case in order to predict thermal comfort levels.

The simulated results indicated that the mean air temperatures of 21.5°C and 32.4°C in the laboratory and workshop, respectively, were in excess of the recommended thermal comfort ranges specified in MS1525, a local energy efficiency guideline for non-residential buildings. However, air velocities above 0.3 m/s were predicted in the two testing facilities, which would be acceptable to most occupants. Based on the calculated PMV derived from the CFD predictions, the thermal sensation of users of the air-conditioned laboratory was predicted as −1.7 where a “slightly cool” thermal experience would prevail, but machinery operators in the workshop would find their thermal environment too warm with an overall sensation score of 2.4. A comparison of the simulated and empirical results showed that the air temperatures were in good agreement with a percentage of difference below 2%. However, the level of correlation was not replicated for the air velocity results, owing to uncertainties in the selected boundary conditions, which was due to limitations in the measuring instrumentation used.

Due to the varying designs, the simulated results of this study are only applicable to laboratory and workshop facilities located in the tropics.

The results of this study will enable building services and air-conditioning engineers, especially those who are in charge of the air-conditioning and mechanical ventilation (ACMV) system design and maintenance to have a better understanding of the thermal environment and comfort conditions in the testing facilities, leading to a more effective technical and managerial planning for an optimised thermal comfort management. The method of this work can be extended to the development of CFD models for other testing facilities in educational institutions.

The findings of this work are particularly useful for both industry and academia as the indoor environment of real engineering testing facilities were simulated and analysed. Students and staff in the higher educational institutions would benefit from the improved thermal comfort conditions in these facilities.

For the time being, CFD studies have been carried out to evaluate thermal comfort conditions in various building spaces. However, the information of thermal comfort in the engineering testing centres, of particular those in the hot–humid region are scantily available. The outcomes of this simulation work showed the usefulness of CFD in assisting the management of such facilities not only in the design of efficient ACMV systems but also in enhancing indoor thermal comfort.

The purpose of this study is to investigate the mediating effect of work engagement on the relationship between learning organization and innovative behavior.

This study used surveys as a data collection tool and implemented structural equation modeling for empirically testing the proposed research model.

The study found that learning organization culture makes a direct and indirect impact on employees' innovative work behaviors. Results from hierarchical multiple regressions and structural equation modeling supported that work engagement fully mediates the relationship between the learning organization and innovative work behaviors.

HRD practitioners can develop effective interventions to enhance their employees' innovative behavior by devoting efforts to create a workplace that promotes collaborative learning culture and work engagement.

This study is valuable to HRD specialists interested in developing effective interventions that encourage employees to engage in innovative behavior.

The purpose of this study is to empirically examine the mediating effect of organizational communication in the relationships among transformational leadership, organizational justice and knowledge sharing within the higher education setting in South Korea.

A sample of 321 university employees, including 151 faculty members and 170 administrative staff members, from a representative private university, participated in the survey as part of a consulting project for university innovation. Structural equation modeling (SEM) was mainly used for data analysis to identify the structural relationship among the research variables.

The results of this study confirmed that transformational leadership positively influences organizational justice and knowledge sharing. However, the influence of organizational justice on knowledge sharing was not statistically significant. The mediating effect of organizational communication among those relationships to increase the members’ knowledge sharing behavior was statistically significant.

In this study, holistic aspects of the organization, including leadership, organizational culture and organizational strategy, were examined for encouraging employees’ knowledge sharing behavior while an organization undergoes innovational changes. More practically, this study suggested that organizational communication could be used as one of the critical strategies in the process of university innovation.