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A novel proportional integral derivative-extended state disturbance observer-based control (PID-ESDOBC) algorithm is proposed to solve the nonlinear hydrodynamics, parameters perturbation and external disturbance in yaw control of remote operated vehicles (ROVs). The effectiveness of PID-ESDOBC is verified through the experiments and the results indicate that the proposed method can effectively track the desired attitude and attenuate the external disturbance.

This study fully investigates the hydrodynamic model of ROVs and proposes a control-oriented hydrodynamic state space model of ROVs in yaw direction. Based on this, this study designs the PID-ESDOBC controller, whose stability is also analyzed through Kharitonov theorem and Mikhailov criterion. The conventional proportional-integral-derivative (PID) and active disturbance rejection control (ADRC) are compared with our method in our experiment.

In this paper, the authors address the nonlinear hydrodynamics, parameters perturbation and external disturbance problems of ROVs with multi-vector propulsion by using PID-ESDOBC control scheme. The advantage is that the nonlinearities and external disturbance can be estimated accurately and attenuate promptly without requiring the precise model of ROVs. Compared to PID and ADRC, both in overshoot and settling time, the improvement is 2X on average compared to conventional PID and ADRC in the pool experiment.

The delays occurred in the control process can be solved in the future work.

The attitude control is a kernel problem for ROVs. A precise kinematic and dynamic model for ROVs and an advanced control system are the key factors to obtain the better maneuverability in attitude control. The PID-ESDOBC method proposed in this paper can effectively attenuate nonlinearities and external disturbance, which leads to a quick response and good tracking performance to baseline controller.

The PID-ESDOBC algorithm proposed in this paper can be ensure the precise and fast maneuverability in attitude control of ROVs or other underwater equipment operating in the complex underwater environment. In this way, the robot can better perform undersea work and tasks.

The dynamics of the ROV and the nominal control model are investigated. A novel control scheme PID-ESDOBC is proposed to achieve rapidly yaw attitude tracking and effectively reject the external disturbance. The robustness of the controller is also analyzed which provides parameters tuning guidelines. The effectiveness of the proposed controller is experimental verified with a comparison by conventional PID, ADRC.

With the increasing demand for lightweight parts, the quality of the inner structure gained growing attention from different kinds of fields. As the quality of the overhanging surface was one of the most important factors affecting inner structure formation, its quality still needs to improve. This paper aims to clarify the change of the overhanging surface quality caused by different bending angles.

The structure of the inner hole was redesigned according to the different performances of the overhanging and side inner surface. The experimental results revealed why different surface qualities can be seen under different bending angles. According to the experimental data, the inner structure was redesigned to increase its overall performance.

The results revealed that when the bending angle was small, the slope of the overhanging surface increased which lead to the decreasing length of the powder-supported layer. However, less space on bending angle resulted in the accumulation of unmelted powder which leads to the increasing of sinking distance. When the bending angle was too large, the slope of the overhanging surface decreased and the length of the molten pool which was supported by powder increased. It resulted in the sinking of the molten pool caused by the gravity of powder and its attachment.

This paper is the first work to study the relationship between bending angle and overhanging surface quality as far as the authors know. The different performances of left and right overhanging surfaces also have not been revealed in other research studies to the best of the knowledge.

A novel fault-tolerant control (FTC) method is proposed to assure the stability of the remote-operated vehicle (ROV) by considering the thruster failure-induced model perturbations. The stability of the ROV with failures is guaranteed and optimized with the determined model perturbation set. The effectiveness of the double-boundary interval fault-tolerant control (DBIFTC) is verified through the experiments and proves that the stability is well maintained, which demonstrates a decent performance.

This paper studies a control problem for a multi-vector propulsion ROV by using the DBIFTC method in the presence of thruster failure and external disturbances. The ROV kinematics and dynamical models with multi-vector-arranged thruster failure are investigated and formulated for control system design.

In this paper, the authors address the FTC problem of ROV with multi-vector thrusters and propose a DBIFTC scheme. The advantage is that as the kinematic system model of ROV is preanalyzed and identified, the DBIFTC becomes more effective. The mathematical stability of the system under the proposed control scheme can be guaranteed.

The ROV model used in this paper is based on the system identification of experimental data. Although this model has real experimental value and physical significance, the accuracy can be further improved.

Cable-controlled underwater ROVs are widely used in military missions and scientific research because of their flexibility, sufficient load capacity and real-time information transmission characteristics. The DBIFTC method proposed in this paper can effectively reduce the problem of underwater vehicle under propeller failure or external disturbance and save unnecessary cost.

The DBIFTC method proposed in this paper can ensure the attitude stability of ROV or other underwater equipment operating in the event of propeller failure or external disturbance. In this way, the robot can better perform undersea work and tasks.

The kinematics and failure mechanisms of the ROV with multi-vector propulsion system are investigated and established. An optimized DBIFTC scheme is investigated to stabilize ROV yaw attitude under the thruster failure condition. The feasibility and effectiveness of the DBIFTC is experimentally validated.

Port competition attracted much scholarly attention in Northwest Europe during the 1980s. Following the rise of powerful economies in East Asia, particularly during the 1980s and 1990s, port competition has become an important phenomenon with the top five container ports in the world being located in the region. This paper aims to overview major port competition issues and outlines and analyzes the main alternative methodologies that researchers have employed to address them, referring to 70 items, mostly papers but including a few books and reports

The purpose of this paper is to assess the adoption of internet of things (IoT) element with the view of increasing usage so that benefits of convenience, increased performance and timely completion of work can be improved. This research was conducted so that there can be increase in the usage of IoT elements for construction performance and sustainability.

The study adopted survey design and various construction professionals were used to assessing the level of adoption of IoT elements. Convenience sample was used by distributing the structured questionnaire to registered professionals. Mean score, bar chart, Kruskal–Wallis H test, one-sample t-test and Shapiro–Wilk were used for analyzing the data gathered.

The findings revealed that wireless fidelity, visualization, wireless sensor networks, Bluetooth, electronic product code and internet protocol are the most adopted element of IoT in the industry. The study also shows that there are areas where there is no significance attached by construction professionals in the usage of IoT elements. These are data storage and analytics, barcode, Zigbee, gateway, near field communication and actuators. It is recommended that less significant areas can be improved through training and educating professionals about the whole concept of IoT and other design professionals. When the importance of IoT elements are understood it will help in the level of adoption.

This paper highlights the possible ways of increasing the adoption of IoT elements with a view to achieving better usage for convenience, high productivity of workers and easy access to information.

The purpose of this study is to examine the relationships among a learning organization, knowledge and financial performance using the Dimensions of the Learning Organization Questionnaire and its abbreviated version.

This study used a secondary data set and performed second-order factor analysis and structural equation modeling for testing the proposed relationships.

The study found that a learning organization has a positive effect on knowledge performance; knowledge performance has a positive effect on financial performance; and knowledge performance fully mediates the relationship between a learning organization and financial performance.

This study contributes to validating the current dimensionality of the theoretical framework of a learning organization proposed by Watkins and Marsick (1993, 1996) and offers a valid conceptual framework of the relationship among the learning culture and organizational performance dimensions.

This study re-stresses the significance of the learning and knowledge generated by the human resources of an organization and developed by human resource development practitioners.

This study is valuable to human resource development scholars and practitioners interested in improving and measuring organizational performance.

While musicians contribute a great deal to the atmosphere of a city like Austin, Texas, they may be poorly compensated for their work. Their low salaries, personality traits, and lifestyle preferences may also mean that musicians may be reluctant to engage in preventative health strategies. Frequently lacking sufficient health insurance, musicians may have difficulty coping with health challenges such as depression and anxiety, hearing loss, poor nutrition, and alcohol and substance abuse.

This chapter opens with background on the music scene in Austin, Texas and moves to a description of a recent study on how musicians feel their careers impact their health. This is followed by a literature review that summarizes what is known about musicians’ personalities, their lifestyles, the economic factors they face, and their health disparities. In the last half of the chapter, the author summarizes how libraries currently serve musicians and add recommendations for how libraries might expand these services.

This paper employs the concept of supply chain orientation in container port management and empirically tests whether the measurement models proposed in some notable previous research have universal application. In addition, this study attempts to identify any significant causal relationships between port supply chain orientation and port performance from the view point of shipping companies. In the current study port supply chain orientation was found to have limited effect on customer satisfaction and port competitiveness, which might has been caused by some implemental and practical issues. However, the present study reveals the potential importance of port supply chain management by empirically demonstrating that “closer relationship with shipping lines” and “innovative value added service” could function as critical components for container ports/terminals to improve customer satisfaction and enhance their competitiveness.

This study explores the main factors considered when shippers and container shipping lines select their import/export and transshipment ports. In the present study, 38 container port selection indices were chosen from the previous research and field interviews. The scores of the 38 items were collected via survey to the three major maritime/port market players: shippers, shipping lines, and container terminal operators. In order to analyze the different priorities imposed on the port selection factors by the three market players, the ANOVA method has been employed. The empirical test shows the different perceptions about port selection attributes among service suppliers and demanders. In addition, the 38 items have been categorized into seven key factors through an exploratory factor analysis. The ANOVA technique was employed again to analyze the perspective differences for the port selection factors among the market players. The results show that there are significant differences among the players assessing the importance of the three port choice factors: liners and terminal operators give more weight to ‘hinterland and terminal basic conditions’ than shippers; terminal operators do not take ‘line operation’ as seriously as carriers and shippers; the factor of ‘terminal operation’ is more significantly considered by liners and terminal operators than by shippers.

This technology-infused lesson uses the historical fiction book, Rudy Rides the Rails, which is based on the real “Ramblin’ Rudy” who rode in railroad cars searching for work during the Great Depression. Instructional development focuses on students working collaboratively as they investigate how economic factors directly affect living conditions. This lesson incorporates history and basic economic concepts that allow students to understand how global and national conditions affect the lives of people, not only in the past but also currently. This lesson is designed for students in the middle grades but can easily be adapted for high school students.