ROC Naval Academy

Kaohsiung, Taiwan

ROC Naval Academy

Kaohsiung, Taiwan
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Chang C.-S.,Roc Naval Academy | Chen S.-Y.,Kaohsiung Medical University | Lan Y.-T.,I - Shou University
BMC Health Services Research | Year: 2013

Background: Interaction between service provider and customer is the primary core of service businesses of different natures, and the influence of trust on service quality and customer satisfaction could not be ignored in interpersonal-based service encounters. However, lack of existing literature on the correlation between service quality, patient trust, and satisfaction from the prospect of interpersonal-based medical service encounters has created a research gap in previous studies. Therefore, this study attempts to bridge such a gap with an evidence-based practice study. Methods. We adopted a cross-sectional design using a questionnaire survey of outpatients in seven medical centers of Taiwan. Three hundred and fifty copies of questionnaire were distributed, and 285 valid copies were retrieved, with a valid response rate of 81.43%. The SPSS 14.0 and AMOS 14.0 (structural equation modeling) statistical software packages were used for analysis. Structural equation modeling clarifies the extent of relationships between variables as well as the chain of cause and effect. Restated, SEM results do not merely show empirical relationships between variables when defining the practical situation. For this reason, SEM was used to test the hypotheses. Results: Perception of interpersonal-based medical service encounters positively influences service quality and patient satisfaction. Perception of service quality among patients positively influences their trust. Perception of trust among patients positively influences their satisfaction. Conclusions: According to the findings, as interpersonal-based medical service encounters will positively influence service quality and patient satisfaction, and the differences for patients' perceptions of the professional skill and communication attitude of personnel in interpersonal-based medical service encounters will influence patients' overall satisfaction in two ways: (A) interpersonal-based medical service encounter directly affects patient satisfaction, which represents a direct effect; and (B) service quality and patient trust are used as intervening variables to affect patient satisfaction, which represents an indirect effect. Due to differences in the scale, resources and costs among medical institutions of different levels, it is a most urgent and concerning issue of how to control customers' demands and preferences and adopt correct marketing concepts under the circumstances of intense competition in order to satisfy the public and build up a competitive edge for medical institutions. © 2013 Chang et al.; licensee BioMed Central Ltd.

Chang C.-S.,Roc Naval Academy | Chen S.-Y.,Kaohsiung Medical University | Lan Y.-T.,I - Shou University
BMC Medical Informatics and Decision Making | Year: 2012

Background: No previous studies have addressed the integrated relationships among system quality, service quality, job satisfaction, and system performance; this study attempts to bridge such a gap with evidence-based practice study. Methods. The convenience sampling method was applied to the information system users of three hospitals in southern Taiwan. A total of 500 copies of questionnaires were distributed, and 283 returned copies were valid, suggesting a valid response rate of 56.6%. SPSS 17.0 and AMOS 17.0 (structural equation modeling) statistical software packages were used for data analysis and processing. Results: The findings are as follows: System quality has a positive influence on service quality (γ§ssub§11§esub§= 0.55), job satisfaction (γ§ssub§21§esub§= 0.32), and system performance (γ§ssub§31§esub§= 0.47). Service quality (β§ssub§31§esub§= 0.38) and job satisfaction (β§ssub§32§esub§= 0.46) will positively influence system performance. Conclusions: It is thus recommended that the information office of hospitals and developers take enhancement of service quality and user satisfaction into consideration in addition to placing b on system quality and information quality when designing, developing, or purchasing an information system, in order to improve benefits and gain more achievements generated by hospital information systems. © 2012 Chang et al.; licensee BioMed Central Ltd.

Hsu C.-Y.,ROC Naval Academy | Liang C.-C.,Da - Yeh University | Nguyen A.-T.,Da - Yeh University | Teng T.-L.,Hsiuping University of Science and Technology
Ocean Engineering | Year: 2014

The dynamic underwater explosion bubble process is a complex phenomenon with many facets to consider. After detonation, the shockwave quickly strikes nearby structures. The bubble oscillation may then substantially damage the structures, even if the bubble pulse is not large. This is because other effects, such as whipping or water jet impact, often accompany the bubble pulse. This study applied the Eulerian Technique using ABAQUS software to simulate the process of underwater bubble explosion, pulsation and collapse. This approach allows many materials to be used in an Eulerian element and manages with large deformation of materials such as flows and gases. The simulated bubble is equivalent to a bubble generated by 55 g of TNT. Although boundary conditions simplify the model, the method is feasible for simulating bubble dynamics and provides acceptably accurate results on bubble migration in water, pressure pulse, water jet formation, and flow field velocity surrounding the bubble. Future research can use this method to study bubbles, including their interaction with free surfaces and the submerged structures or floating structures. © 2014 Elsevier Ltd.

Wang C.-H.,Chung Cheng Institute of Technology | Huang C.-H.,Roc Naval Academy
RAIRO - Operations Research | Year: 2015

This study aims at the multi-state degraded system with multi-state components to propose a novel approach of performance evaluation and a preventive maintenance model from the perspective of a system's components. The general non-homogeneous continuous-time Markov model (NHCTMM) and its analogous Markov reward model (NHCTMRM) are used to quantify the intensity of state transitions during the degradation process. Accordingly, the bound approximation approach is applied to solve the established NHCTMMs and NHCTMRMs, thus evaluating system performance including system availability and total maintenance cost to overcome their inherent computational difficulties. Furthermore, this study adopts a genetic algorithm (GA) to optimize a proposed preventive maintenance model. A simulation illustrates the feasibility and practicability of the proposed approach. © EDP Sciences, ROADEF, SMAI 2015.

This paper reports on the use of molecular dynamics (MD) simulation to investigate the coupling effects of wettability, surface roughness and interfacial nanobubbles (INBs) on wall–fluid interfaces. The fluid properties close to the wall–fluid interface, such as potential energy, density, diffusion coefficients of fluid molecules and effective slip length are simulated. In the cases without surface nanobubbles, regions with lower potential energy have a higher probability of hosting water molecules. The local translational and rotational diffusion coefficients of water within the cavities are strongly influenced by wettability but largely unaffected by hydrodynamic effects. In cases where INBs exist, variations in wettability result in distinctly different argon morphologies. Argon nanobubbles form a convex shape on Wenzel-like interfaces but a shallow concave shape on Cassie-like interfaces. The phenomenon of water molecules invading grooves tends to occur on Wenzel-like interfaces; however, this depends largely on the morphology of the grooves. The high mobility and high density of argon molecules indicate that the state of the argon molecules within the grooves may require further investigation. Our results also show that the effective slip length is significantly influenced by wall–fluid wettability as well as the morphology of INBs. © 2016 Informa UK Limited, trading as Taylor & Francis Group

Lei P.-R.,ROC Naval Academy
Knowledge and Information Systems | Year: 2015

Rapid growth in location data acquisition techniques has led to a proliferation of trajectory data related to moving objects. This large body of data has expanded the scope for trajectory research and made it applicable to a more diverse range of fields. However, data uncertainty, which is naturally inherent in the trajectory data, brings the challenge in trajectory data mining and affects the quality of the results. Specifically, unlike trajectory collected from vehicles moving along road networks, trajectory data generated by vessels moving free in maritime space have increased the difficulty of sea traffic analysis and anomalous behavior detection. Furthermore, due to the huge volume and complexity of maritime trajectory data, it is hard to define the abnormality of movement behavior and detect anomalies. Additionally, traditional analysis and evaluation by human intelligence is overloaded with the dramatic increasing in amount of maritime trajectory data and is an inefficient approach. Thus, an effective automated method for mining trajectory data and detecting anomalies would be a valuable contribution to maritime surveillance. This paper explores the maritime trajectory data for anomalous behavior detection. We propose a framework for maritime trajectory modeling and anomaly detection, called MT-MAD. Our model takes into account the fact that anomalous behavior manifests in unusual location points and sub-trajectories in the spatial domain as well as in the sequence and manner in which these locations and sub-trajectories occur. This study therefore began by identifying outlying features required for anomaly detection, including spatial, sequential, and behavioral features. We then explore the movement behavior from historical trajectories and build a maritime trajectory model for anomaly detection. The proposed model accurately describes movement behavior and captures outlying features in trajectory data. We then developed an anomaly detection algorithm based on this model in which an indicator is used to evaluate suspicious behavior and scores trajectory behavior according to the defined outlying features. Experiment results demonstrate that the proposed MT-MAD framework is capable of effectively detecting anomalies in maritime trajectories. © 2015 Springer-Verlag London

Jen C.-Y.,ROC Naval Academy | Tai Y.-S.,ROC Military Academy
Materials and Design | Year: 2010

Given the superior strength-to-weight ratio, stiffened panels have been used extensively in the main structure of ships and underwater vehicles. The loads acting on a stiffened panel in a ship is in-plane compression or tension, resulting from the overall hull-girder bending moment or torsion, shear force resulting from the hull-girder shear force, and lateral pressure resulting from the external wave or shock loading. This work addresses the transient responses of a panel structure reinforced by ribs of different sizes to underwater shock loads using non-linear finite element code-ABAQUS. Verification of the reliability was made between the Ramajeyathilagam's experiments results [Ramajeyathilagam K, Vendhan CP, Rao VB. Non-linear transient dynamic response of rectangular plates under shock loading. Int J Impact Eng 2000;24:999-1015, Ramajeyathilagam K, Vendhan CP. Deformation and rupture of thin rectangular plates subjected to underwater shock. Int J Impact Eng 2004;30:699-719] at several different locations on the plates. The shock factor is adopted to describe the shock severity. Additionally, the displacement-time histories under different shock loadings are presented which will be used in designing stiffened panels so as to enhance resistance to underwater shock damage. © 2009 Elsevier Ltd. All rights reserved.

Lei P.-R.,ROC Naval Academy
IEEE ISI 2013 - 2013 IEEE International Conference on Intelligence and Security Informatics: Big Data, Emergent Threats, and Decision-Making in Security Informatics | Year: 2013

As security requirements in coastal water and sea ports, maritime surveillance increases the duty. In this research, we focus on the maritime trajectory data to explore movement behavior for anomaly detection in maritime traffic. Trajectory data records the moving objects' true movement and provides the opportunity to discover the movement behavior for anomaly detection. The multidimensional outlying features are first identified and defined. To deal with the uncertain property of trajectory, a maritime trajectory modeling is developed to explore the movement behavior from historical trajectories and build a maritime trajectory model for anomaly detection. Then, our ongoing work is developing an anomaly detection algorithm to detect anomalous moving objects from real time maritime trajectory stream effectively. This work should contribute the area of maritime security surveillance by trajectory data mining. © 2013 IEEE.

Kao C.-H.,Roc Naval Academy
International Journal of Communication Systems | Year: 2014

Link-16 is a tactical data link currently used by North Atlantic Treaty Organization (NATO) countries, the United States and its allies. The Link-16 waveform features Reed-Solomon codes for channel coding, cyclic code-shift keying for 32-ary baseband symbol modulation, minimum-shift keying for waveform modulation, and frequency hopping for transmission security. In addition to the original errors-only decoding of Reed-Solomon codes, both an errors-and-erasures decoding (EED) and a special concatenated coding are proposed in this paper to determine a better channel coding scheme for a Link-16 waveform with noncoherent detection in the presence of pulsed-noise interference (PNI). The investigation is first carried out both analytically and by simulation for the original Link-16 waveform transmitted over AWGN. It is then accomplished analytically for the proposed waveforms in both AWGN and PNI. The results show that EED achieves the best error rate performance for a Link-16 waveform in both AWGN and PNI when the signal-to-noise ratio is relatively small. When both the signal-to-noise ratio is sufficiently large and the fraction active time of PNI is small, the proposed concatenated coding outperforms both EED and errors-only decoding. © 2012 John Wiley & Sons, Ltd.

The effects of an externally applied perpendicular electric field and surface roughness on water nanodroplets on silicon (Si) substrates are explored using molecular dynamics (MD) simulation. The plain surface of Si (111) lattice and Si substrate with pillar-array roughness were employed as the solid models. Given the various directions and strengths of the external electric field, the variation in average number of wall-fluid interfacial hydrogen bonds formed by each water molecule, and the droplet shape deformation are disclosed using MD simulations. This work explores and compares the droplet shape in the plain surface and substrate with surface nanostructure cases, especially the Cassie and Wenzel states. The qualitative droplet deformation trends under various perpendicular electric fields are summarised. © 2012 Copyright Taylor and Francis Group, LLC.

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