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High-intensity focused ultrasound (HIFU) ablation is a safe and effective minimally invasive option for treating uterine fibromas, but it can cause complications such as abdominal wall defects. Reconstruction of such defects can be challenging, but a latissimus dorsi musculocutaneous free flap can be used to restore the integrity of the myofascial layer and provide external cutaneous coverage. Herein, we present a case report of a 37-year-old woman who underwent HIFU for an 8-cm uterine fibroma and subsequently developed a large abdominal wall defect with necrosis of the rectus muscle. The latissimus dorsi musculocutaneous free flap was used to reconstruct the rectus muscle and cover the abdominal soft tissue, resulting in successful engraftment without complications. We present our experience using a latissimus dorsi musculocutaneous free flap to reconstruct a large HIFU-induced composite defect in the abdominal wall.

Toe injuries frequently occur as traumatic or oncologic defects. Compared with finger reconstruction, toe reconstruction has been rarely reported in the literature, because of the difficulty of toes’ relatively thin soft tissue envelope, their requirement for relatively challenging surgical techniques, and the slight improvements in gait. Therefore, toe reconstruction can be challenging for plastic surgeons, especially in cases with exposure of a tendon, bone, or joint. Herein, we present a case study of a 54-year-old woman with squamous cell carcinoma in situ (Bowen disease) that subsequently resulted in a defect on her second toe. A serratus anterior fascia free flap could be a good option for toe reconstruction due to its large caliber, lengthy pedicle, relatively easy dissection, and thin muscle bulk. We present our unique experience using the serratus anterior fascia free flap for the reconstruction of an oncologic toe defect.

This technical paper deals the practical transformation algorithms between several lunar reference frames which will be used for Korea pathfinder lunar orbiter (KPLO) flight operation. Despite of various lunar reference frame definitions already exist, use of a common transformation algorithm while establishing lunar reference frame is very important for all members related to KPLO mission. This is because use of slight different parameters during frame transformation may result significant misleading while reprocessing data based on KPLO flight dynamics. Therefore, details of practical transformation algorithms for the KPLO mission specific lunar reference frames is presented with step by step implementation procedures. Examples of transformation results are also presented to support KPLO flight dynamics data user community which is expected to give practical guidelines while post processing the data as their needs. With this technical paper, common understandings of reference frames that will be used throughout not only the KPLO flight operation but also science data reprocessing can be established. It is expected to eliminate, or at least minimize, unnecessary confusion among all of the KPLO mission members including: Korea Aerospace Research Institute (KARI), National Aeronautics and Space Administration (NASA) as well as other organizations participating in KPLO payload development and operation, or further lunar science community world-wide who are interested in KPLO science data post processing.

This study was conducted to understand the relationship among emotional exhaustion, job satisfaction, and emotional intelligence of hotel front desk employees. The importance of this study are focu...

The ground tracking support is a critical factor for the navigation performance of spacecraft orbiting around the Moon. Because of the tracking limit of antennas, only a small number of facilities can support lunar missions. Therefore, case studies for various ground tracking support conditions are needed for lunar missions on the stage of preliminary mission analysis. This study analyzes the ground supporting condition effect on orbit determination (OD) of Korea Pathfinder Lunar Orbiter (KPLO) in the lunar orbit. For the assumption of ground support conditions, daily tracking frequency, cut-off angle for low elevation, tracking measurement accuracy, and tracking failure situations were considered. Two antennas of deep space network (DSN) and Korea Deep Space Antenna (KDSA) are utilized for various tracking conditions configuration. For the investigation of the daily tracking frequency effect, three cases (full support, DSN 4 pass/day and KDSA 4 pass/day, and DSN 2 pass/day and KDSA 2 pass/day) are prepared. For the elevation cut-off angle effect, two situations, which are 5 deg and 10 deg, are assumed. Three cases (0%, 30%, and 50% of degradation) were considered for the tracking measurement accuracy effect. Three cases such as no missing, 1-day KDSA missing, and 2-day KDSA missing are assumed for tracking failure effect. For OD, a sequential estimation algorithm was used, and for the OD performance evaluation, position uncertainty, position differences between true and estimated orbits, and orbit overlap precision according to various ground supporting conditions were investigated. Orbit prediction accuracy variations due to ground tracking conditions were also demonstrated. This study provides a guideline for selecting ground tracking support levels and preparing a backup plan for the KPLO lunar mission phase.

Crowdfunding in tourism and leisure projects appears to be growing. However, little is known about why individuals participate in incentive crowdfunding from a theoretical perspective. To address t...

Growing concerns over the environment and climate has led to increased interest in environmentally friendly eating out, especially with respect to the need to reduce waste in the restaurant and cat...

Destination selection by international associations is a dynamic and complex decision-making process in which many stakeholders participate. In this process, key decision makers in associations engage in a series of individual decision-making processes based upon their own perceptions and decision criteria. The overall goal of this study is to understand the decision-making process and identify important decision-making criteria in international associations by applying a mixed-methods approach. This study reveals the complex structure and role of international association buying centers in the process of destination selection, and it identifies 24 important but underexplored attributes affecting this process based on a series of qualitative and quantitative research methods. The findings serve as a foundation for better marketing strategies in destination marketing organizations.

Sustainability continues as one of the most commonly discussed trends within the hotel industry. An extensive comprehensive review of previous literature identified 128 articles focusing on sustain...

Korea’s first lunar mission, the Korea Pathfinder Lunar Orbiter (KPLO), aims to launch in mid-2022 via the Space-X Falcon-9 launch vehicle. For the successful flight operation of KPLO, the Korea Aerospace Research Institute (KARI) has designed and developed the Flight Dynamics Subsystem (FDS). FDS is one of the subsystems in the KPLO Deep-Space Ground System (KDGS), which is responsible for the overall flight dynamics-related operation. FDS is currently successfully implemented and meets all of the requirements derived from the critical design phases. The current work addresses the design and implementation results for the KPLO FDS. Starting from overviews on KPLO payloads, bus systems, and mission trajectory characteristics, a review on KDGS is also treated briefly. Details on the design philosophy, unique characteristics, and functionalities of all six different modules nested inside the FDS with its Graphical User Interface (GUI) design are discussed. Moreover, efforts currently devoted to the flight operation preparation of the KPLO are summarized, including many collaborative works between KARI and the National Aeronautics and Space Administration (NASA) teams.

Purpose This paper aims to systematically develop a sustainability framework and guidelines for the green convention industry to cover the entire process of hosting a convention. Design/methodology/approach The guidelines were designed in three phases: defining a sustainability framework for a green convention, conducting a three-round Delphi survey and developing comprehensive guidelines. The relative weights and/or importance were calculated and compared based on questionnaires and the analytic hierarchy process method. Findings This study summarized 153 sustainable practices and their relative importance (seven categories and 37 subcategories) to suggest future directions and managerial implications for academia and practitioners to cope with negative environmental impacts and to create an environmentally sustainable convention industry. Research limitations/implications Because the proposed framework and guidelines were developed in a particular environment, their applicability might be improved by further review prior to translating them into another context. Practical implications This study provides implications to help practitioners plan and execute events in more environmentally and socially responsible ways. Practitioners may use the proposed guidelines, either as a whole or in part, to select the areas that are most applicable or in need of attention. Additionally, the guidelines may be used as an evaluation framework after hosting a convention to indicate specific ways to reduce harmful environmental practices and the importance of each practice. Originality/value The proposed sustainability framework and guidelines consider all aspects of the convention industry, including all possible aspects of stakeholders that may affect convention organizers and participants, as well as related industries.

Rad51 is a key component of homologous recombination (HR) to repair DNA double-strand breaks and it forms Rad51 recombinase filaments of broken single-stranded DNA to promote HR. In addition to its role in DNA repair and cell cycle progression, Rad51 contributes to the reprogramming process during the generation of induced pluripotent stem cells. In light of this, we performed reprogramming experiments to examine the effect of co-expression of Rad51 and four reprogramming factors, Oct4, Sox2, Klf4, and c-Myc, on the reprogramming efficiency. Co-expression of Rad51 significantly increased the numbers of alkaline phosphatase-positive colonies and embryonic stem cell-like colonies during the process of reprogramming. Co-expression ofRad51 significantly increased the expression of epithelial markers at an early stage of reprogramming compared with control cells. Phosphorylated histone H2AX (γH2AX), which initiates the DNA double-strand break repair system, was highly accumulated in reprogramming intermediates upon co-expression of Rad51. This study identified a novel role of Rad51 in enhancing the reprogramming efficiency, possibly by facilitating mesenchymal-to-epithelial transition and by regulating a DNA damage repair pathway during the early phase of the reprogramming process.

This study aims to estimate visitors’ consumption benefits using the double-bounded dichotomous choice contingent valuation method. The results of this study show that the per capita consumption benefit of the F1 Korea Grand Prix, a study context used in this study, were approximately US$307 and then, the total aggregated economic value generated by the event was US$49,262,301 in 2011. These results indicate that visitors of the F1 Korea Grand Prix perceive huge economic benefits from their visitation and activities during the event. In addition, the results show that prior visit experience and a sport identification are significantly associated with visitors’ perceived consumption benefits while other variables (e.g. age, gender, nationality, automotive club membership) are not. Several theoretical, practical, and methodological implications of this study are discussed.

This paper presents the contribution of the international meeting industry to the Korean national economy. To obtain more accurate results, the study adopted three improvements over previous research: consideration of both supply and demand; direct expenditure surveys of participants and hosts; and re-categorization of related business sectors. The results of the input-output analysis showed that per capita expenditure for international and domestic participants was US$2,432.4 and US$459.3, respectively, and the per capita average budget was US$562.1. Based on these findings, the total contribution of the international meeting industry to the Korean economy exceeds US$1,343.2 million in output, US$236.6 million in personal income, US$589.3 million in value added, US$61.5 million in tax revenue and 16,336 full-time-equivalent jobs. These results provide two key implications, providing evidence of the importance of both the supply and demand sides and the relative importance of each sub-industry for increasing economic benefit.

The control moment gyroscope(CMG) which is well known as an effective high-torque-generating device is applicable to space vehicles, airplanes, ships, automobiles, robotics, etc. for attitude stabilization and maneuver. This paper deals with the overall details of 100Nm-class CMG development for various industrial applications, and provides the activities and results associated with the CMG system-level requirement analysis, the motor subsystem design/manufacturing/integration, the construction of ground support equipment, and the performance test and evaluation. The performance test reveals that the CMG generates the torque output more than 120Nm in as-designed operation of spin motor and gimbal motor.

A spherical reaction wheel is a novel three-axis induction motor consisting of a spherical rotor and electromagnets. The electromagnets allow the rotor to levitate and to rotate about any desired axis without mechanical contact. A benefit of the actuator is to control the satellite for three-axis attitude using the single spherical reaction wheel. In this study, a prototype model of the spherical reaction wheel with a single rotating axis is developed, and a feasibility study on the actuator is conducted. The actuator system is designed through electromagnetic field analyses of the spherical rotor in order to evaluate the levitation force and torque. Dynamic performance tests are carried out under electromagnetic rotation and levitation conditions, and torque-speed characteristics are investigated. Using the test data, torque modeling and velocity control simulations are also performed. Finally, closed loop speed control tests are conducted on the experimental model. The model shows that the maximum torque and speed are 0.7 N m and 13,500 rpm, respectively, and the speed control error is less than 4%.

Two axis gimbal type X-band antenna system has been widely used to effectively transmit the real time image data from the observation satellite to the ground station. The micro-vibration generated by stepping motor actuation and imperfect intermeshed gear configuration of the antenna is one of the sources to degrade the image quality. To guarantee a high quality image of high resolution observation satellite, micro-vibration isolation of X-band antenna is required. In this paper, the X-band antenna vibration isolation system using pseudoelastic SMA(Shape Memory Alloy) mesh washer has been newly suggested. The basic characteristics of the SMA mesh washer isolator proposed in this study has been measured through static load tests and its effectiveness has been demonstrated by the micro-vibration isolation test of the X-band antenna.

In this paper we examine exhibition attendees’ experience and mindfulness within the exhibition industry, and identify the role of mindfulness on the evaluation of their experience. In the service industry, customer experience plays a central role in increasing satisfaction and loyalty, and the concept of mindfulness contributes to positive customer experience. The empirical results of the paper reveal that the on-site and post-evaluation of exhibition attendees’ experience are significantly different across various levels of mindfulness. In addition, several demographic and exhibition-related characteristics are statistically different between groups segmented by the level of mindfulness. Both theoretical and practical implications are covered in the discussion section.

Reaction wheel assemblies (RWAs) are a source of disturbance in satellites, and they are regarded as the largest jitter contributor in optical payloads. In order to ensure a stringent jitter requirement, the wheel disturbance effects on spacecraft should be predicted precisely prior to launch through analytical or experimental approaches. For this purpose, the wheel disturbance should be identified and modeled accurately. In the present study, a micro-vibration model of the RWA is introduced through coupling an analytical wheel model and an empirical disturbance model; furthermore, a parameter estimation process of the coupled model from the micro-vibration disturbance data is proposed. In order to verify the modeling and estimation techniques, a micro-vibration model of a numerical RWA is established and its estimation error is validated. Then, the micro-vibration model is extended to consider an axial disturbance and a measurement offset effect. Finally, the micro-vibration model is applied to a commercial RWA and the model parameters are extracted from the disturbance test data of the RWA using the parameter estimation process. The analytical and experimental results demonstrate that the proposed micro-vibration model and parameter estimation process are effective in the dynamic disturbance modeling of RWAs.

In this work, satellite FE (finite element) model updating for the prediction of the effect of micro-vibration is described. In the case of satellites launched in low earth orbit, high agility and more mission accomplishments are required by the customer in order to procure many images from satellites. To achieve the goal, many mechanisms, including high capacity wheels and antennas with multi-axis gimbals have been widely adopted, but they become a source of micro-vibration which could significantly deteriorate the quality of images. To investigate the effect due to the micro-vibration in orbit on the ground, a prediction is conducted through an integrated model coupling the measured jitter sources with FE (finite element) model. Before prediction, the FE model is updated to match simulation results with the modal survey test. Subsequently, the quality of FE model is evaluated in terms of frequency deviation error, the resemblance of mode shapes and FRFs (frequency response functions) between test and analysis.

TFIIS is a transcription elongation factor conserved in frog, mouse and human. Recently, knockdown of TCEA1, the most well-characterized isoform of TFIIS, by RNA silencing was reported to inhibit cancer cell proliferation and induce apoptosis in breast, lung and pancreatic cancer cell lines through activation of p53 (Hubbard et al., 2008 [1]). However, the functions of other TFIIS isoforms are poorly defined. The present study shows that TCEA3, an isoform of TFIIS, can trigger ovarian cancer-specific cell death by activating the JNK signaling pathway. TCEA3 expression is low in ovarian cancer cell lines compared to noncancerous ovarian epithelial cells. Suppression of TCEA3 in noncancerous ovarian epithelial cells promotes cell growth whereas ectopic expression of TCEA3 in ovarian cancer cell lines induces the caspase-dependent mitochondrial cell death pathway. Molecular and chemical inhibition assays show that the interaction of TCEA3 with TGFβ receptor I induces cell death in ovarian cancer cell through Smad-independent activation of the JNK pathway. These results reveal that TCEA3 induces a novel apoptotic mechanism in OEC, which provides TCEA3 as a novel target to develop therapeutics of ovarian cancer.

Malignant gliomas are the most common primary brain tumor in adults. A number of genes have been impli- cated in glioblastoma including mutation and deletion of PTEN. PTEN is a regulator of PI3K-mediated Akt signaling pathways and has been recognized as a therapeutic target in glioblastoma. To achieve potent therapeutic inhibition of the PI3K-Akt pathway in glioblastoma, it is essential to under- stand the interplay between the regulators of its activation. Here, ectopic expression of PTEN in the U-87MG human glioblastoma-astrocytoma cell line is shown to result in the depletion of glioblastoma stem cells (GSCs) and to cause growth retardation and senescence. These effects are likely to be associated with PTEN-mediated cooperative perturba- tion of Akt and Stat3 signals. Using an in vivo rat model of glioblastoma, we showed that PTEN-overexpressing U-87MG cells failed to induce tumor formation, while untreated U-87MG cells did so. Furthermore, cells expressing the phos- phorylated form of Stat3 were completely absent from the brain of rats implanted with PTEN-overexpressing U-87MG cells. Based on these results, PTEN appears to function as a crucial inhibitor of GSCs and as an inducer of senescence, suggesting that functional enhancement of the PTEN pathway will be useful to provide a therapeutic strategy for targeting glioblastoma.

A 2-axis gimbal system is one of main disturbance sources affecting image jitter response of a satellite. The gimbal system comprises azimuth stage and elevation stage, and these pointing mechanism can be rotated by stepping motors about its azimuth and elevation axes simultaneously. Because of the complex and coupled dynamic motion of the gimbal system, its moment of inertia and structural modes can be changed according to the system configuration, and thus the gimbal system generates complicated and non-linear disturbance characteristics. In order to improve the jitter response of a spacecraft, it is an indispensable process to reduce the micro-vibration disturbance level of the antenna system. In the present research, a 2-axis gimbal system was manufactured and then its micro-vibration test was performed in terms of two types of stepping motors(2-phase and 5-phase). The test results show that the disturbance level of the gimbal system can be reduced by replacing the 2-phase stepping motor with the 5-phase one, and the average disturbance attenuation ratio is 56 % in peak level and 48 % in standard deviation level. The experimental results confirm that it is an efficient jitter reduction method to adopt a high-phase stepping motor.

In the present study, a feasibility study on an innovative satellite attitude control actuator is performed. The actuator is specially designed to generate the reaction torque in an arbitrary axis, so that a satellite attitude can be controlled by using itself. It consists of a spherical flywheel and electromagnets for levitation and rotation control of the ball. As the earlier study, a rotating performance test on the spherical actuator is conducted in a single rotating axis and vertical levitation condition. From the test results, it can be confirmed that the maximum speed and torque of the innovative device are 7,200rpm and 0.7Nm, respectively. Using a velocity-voltage characteristic curve of the spherical motor, an open-loop control (V/f constant control) is performed, and the test results show excellent control performance in acceleration and deceleration phases.

In this research, we deposited a W-N thin film for a diffusion barrier layer on a Si (100) substrate to reduce the thickness from 100 to 30 nm by rf magnetron sputtering at a nitrogen flow rates of 0, and 0.5 sccm at a 600 °C annealing temperature. The crystalline structures and the nano-surface properties, such as the hardness, and the elastic modulus of the W or the W-N thin films, were determined using X-ray diffraction and Nano-indenter (Hysitron Corp.: TriboIndenter) systems, respectively. The Nanoindenter system has been established as a powerful method to characterize the mechanical properties of the nano-surface in W-N thin films. For the measurements, we convert theWeibull distribution and quantitatively define the thin-film stability. The hardness and the RMS surface roughness of the W-N thin film after annealing at 600 °C changed from 2.75 to 7.91 GPa and from 2 to 1.13 nm, respectively, as the thickness was reduced from 100 to 30 nm at a N2 gas flow of 0.5 sccm.

This study aimed to estimate the economic impact of the `2011 Seoul Motor Show` using a direct survey-based regional input-output(I-O) model. Based on the regional I-O table, Exhibition multipliers were derived with respect to output, income, employment, value-added and indirect tax. Attendees` survey was conducted to estimate per capita expenditure. The results of this study indicated that all attendees of `2011 Seoul Motor Show` generated 53.1 billion Won of output impact, 11.7 billion Won of income impact, 24.1 billion Won of Value-added impact, 2.6 billion Won of tax impact, and 1,030 part-time and full-time jobs throughout direct and indirect effects. Another result of this study was that output multiplier of the exhibition industry was similar with other industries, however, income, employment and value-added multipliers were relatively larger than those of other industries.

A reaction wheel assembly(RWA) is the largest disturbance source that can induce high frequency micro-vibration on an optical payload of satellites. To ensure a tight pointing-stability budget of satellites, the RWA disturbance effect on spacecraft should be accurately analyzed and evaluated for whole design phases. For this purpose, the micro-vibration disturbance of RWA should be precisely measured. In the present study, two measurement methods on RWA micro-vibration disturbances are compared and investigated. One is a free run-down speed test and the other is a constant speed test. The micro-vibration data measured by the two methods are analyzed in terms of spectrum characteristics, static and dynamic imbalance values, and root sum square(RSS) values. The analysis results show that both methods can measure very similar results in time and frequency domains and that the free run-down speed method is more adequate in respects to wheel friction modeling, noise rejection of imbalance and RSS peak evaluation.

This paper addresses the flapping frequency-dependent trim flight characteristics of a bioinspired ornithopter. An integrative ornithopter flight simulator including a modal-based flexible multibody dynamics solver, a semiempirical reduced-order flapping-wing aerodynamic model, and their loosely coupled fluid―structure interaction are used to numerically simulate the ornithopter flight characteristics. The effect of the fluid―structure interaction of the main wing is quantitatively examined by comparing the wing deformations in both spanwise and chordwise directions, with and without aerodynamic loadings, and it shows that the fluid―structure interaction created a particular phase delay between the imposed wing motion and the aeroelastic response of the main wing and tail wing. The trimmed level flight conditions of the ornithopter model are found to satisfy the weak convergence criteria, which signifies that the longitudinal flight state variables of ornithopters need to be bounded and that the mean value of the variables are converged to the finite values. Unlike conventional fixed-wing aerial vehicles, the longitudinal flight state variables, such as forward flight speed, body pitch attitude, and tail-wing angle of attack in trimmed level flight, showed stable limit-cycle oscillatory behaviors with the flapping frequency as the dominant oscillating frequency. The mean body pitch attitude and tail-wing angle, and the root-mean-square value of the body pitch attitude, decreased as the flapping frequency increased. In addition, the mean forward flight speed is found to almost linearly increase with the flapping frequency.

This work was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2007-313- D00122). The second author would like to thank the Brain Korea 21 Project in 2010. The authors would like to thank James D. DeLaurier of the University of Toronto and M. Okamoto of the Akita National College of Technology for their gracious support for this study. The authors also thank anonymous reviewers and the Editor for their valuable comments and suggestions.

In this study, an efficient ornithopter aerodynamic model, which is applicable to ornithopter wing design considering fluid-structure interaction or ornithopter flight dynamics and control simulation, was proposed and experimentally validated through the wind tunnel experiments. Due to the ornithopter aerodynamics governed by unsteady low Reynolds number flow, an experimental device was specially designed and developed. A part of the experimental device, 2-axis loadcell, was situated in the non-inertial frame; the dynamic calibration method was established to compensate the inertial load for pure aerodynamic load measurements. The characteristics of proposed aerodynamic model were compared with the experimental data in terms of mean and root-mean-square values of lift and drag coefficients with respect to the flow speed, flapping frequency, and fixed angle of attack.

Reaction wheel assemblies(RWA) are expected to be one of the largest high frequency disturbance sources to the optical payload of satellites. To ensure the tight pointing-stability budget and high image quality of satellites, a vibration isolation device should be applied to the main disturbances. For developing the isolating system, the disturbances need to be identified and modeled accurately. In the present study, a modeling technique of RWA and its disturbance was described. The micro-vibration disturbances were generated numerically by using an analytical wheel and disturbance model. The parameter estimation scheme of the model was suggested, and the RWA and disturbance modeling technique was verified through the numerical example analysis. The analytical results show that the wheel and disturbance model can be accurately established by using the modeling technique proposed in the present study. The wheel and disturbance model is expected to be useful for development of the RWA isolator system.

A reaction wheel is commonly used, as an important actuator, to control the attitude of a satellite. Operation of the reaction wheel plays a role of an excitation source to loading equipment inside the satellite. As requirements for environmental vibration to manifest the performance of precision equipment are getting more stringent, the research for analysis or reduction of unwanted action force in high frequency range when operating the reaction wheel is necessary. In this paper, the procedure to extract input forces and damping of a rotor system of reaction wheel is suggested. The analysis for measured action forces of reaction wheel is accomplished and important higher harmonics of action forces are determined. The input forces and damping of the rotor system are, then, extracted by curve-fitting and a particular solution for input force.

The efficient dynamic modeling of a satellite with flexible solar arrays is established by using the component mode synthesis technique. A flexible satellite model can be defined as the assembly of two sub-structures, central body and solar array. The reduced models of each substructure, which are expressed in each local frame, are coupled with respect to the satellite reference frame. The dynamic modeling method is applied to the numerical example of a satellite with a single solar array, and is verified by investigating the transfer function results with considering the solar array rotation.

The component mode synthesis (CMS) method is widely used to establish reduced dynamic models of complex structures so that iterative problems such as flutter analyses can be efficiently analyzed with reasonable cost and time. In the present study, a structural coupling method is developed for the dynamic analysis of a nonlinear structure consisting of substructures connected by nonlinear interfaces such as nonlinear hinge joints or sliding mode conditions. In order to verify the coupling method extended to consider the hinge joints, a numerical plate model consisting of two substructures and torsional springs is synthesized, and its modal parameters are compared with analysis data. The extended coupling method is further improved to consider the sliding mode condition. The improved coupling method is applied to a three-substructure-model with nonlinearity of sliding lines between the substructures. Finally, using the proposed coupling method, a dynamic model of a tilting structure consisting of two substructures with sliding line conditions is synthesized, and its dynamic characteristics are investigated. The analysis results show that the improved coupling method is effectively applicable to the dynamic analysis of a nonlinear structure with the sliding mode condition.

This study describes the development of a bio-mimetic flapping wing and the aerodynamic characteristics of a flexible flapping wing. First, the flapping wing is designed to produce flapping, twisting, and camber motions by using a bio-mimetic design approach. A structural model for a macro-fiber composite (MFC) actuator is established, and structural analysis of a smart flapping wing with the actuator is performed to determine the wing configuration for maximum camber motion. The analysis model is verified with the experimental data of the smart flapping wing. Second, aerodynamic tests are performed for the smart flapping wing in a subsonic wind tunnel, and the aerodynamic forces are measured for various test conditions. Additionally, the effects of camber and chordwise wing flexibility on unsteady and quasi-steady aerodynamic characteristics are discussed. The experimental results demonstrate that the effect of the camber generated by the MFC produces sufficient aerodynamic benefit. It is further found that chordwise wing flexibility is an important parameter in terms of affecting aerodynamic performance, and that lift produced in a quasi-steady flow condition is mostly affected by the forward speed and effective angle of attack.

This study investigates dynamic structural displacements estimation using displacement–strain relationship and measured strain data. Strain signals are obtained from fiber Bragg grating (FBG) sensors that have an excellent multiplexing ability. Vibration experiments were performed with aluminum and acryl beam specimens. The beam structures were subjected to various loading conditions, and deformed shapes were reconstructed by using strain signals. The estimated displacements show good agreements with those measured directly from laser displacement sensors. In present study, it is confirmed structural displacements can be estimated using strain data without displacement measurement.