• IE interfaces
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• v.11 no.2
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• pp.65-78
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• 1998

The letters of the automobile tire are usually engraved on the side-wall. The shape of the side-wall is a sculptured surface generated by the rotational sweeping of a profile curve. The letters laid on the side-wall are usually designed by a 2-dimensional CAD. It is impossible to machine the letters on the surface accurately by 3-axis NC machining, because the axis of cutter should be tilted to align with the normal vector of the surface. In this case. the degree of freedom for the machine is at least four. This paper describes an idea for tool path generation of a 4-axis machine by using the 2-dimensional CAD data of the letters and the surface of the side-wall. This study includes the following procedures; (1) measuring the profile of the side-wall surface and curve-fitting of the measured points. (2) the 'non-parallel projection' of the letters on the side-wall, and (3) an inverse kinematics of the 4-axis lettering machine. Procedures in this paper are programmed in C-language on Windows95 environment. With a PC based CNC controller and a 4-axis lettering machine. these are tested sucessfully for the practical use.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.4
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• pp.388-395
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• 2014

Nowadays unmanned ground systems are used in supporting of surveillance and explosive ordnance disposal. Also, we expect that will be used to remarkably enhance combat capability through network-based cooperative operations with other combat systems. In order to effectively develop those unmanned systems, we needs a systematic method to analyze combat effectiveness and validate required operation capabilities. In this paper, we propose a practical approach to simulate remote-operated unmanned ground systems by using OneSAF, an US-Army simulation framework. First of all, we design a simulation model of unmanned system by integrating with core components for wireless communications and remote control of mobility and fire. Next, we extend OneSAF functionality to create communication links that connects a remote controller with an unmanned vehicle and define a simulated behavior to operate unmanned vehicles via the communication links. Finally, we demonstrate the feasibility of the proposed model within OneSAF and summarize system effectiveness analysis results.

• Journal of the Korean Institute of Navigation
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• v.14 no.4
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• pp.17-30
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• 1990

Since L.A. Zadeh introduced the theory of fuzzy sets in 1965, E.H. Mamdani applied the theory to the steam engine control in 1974. Since then, scientists have shown a great deal of interests in its application to practical problems and the possibility of the application of the theory a more complicate system has been increasing greatly. In the fuzzy control, the qualitative knowledge and intuition that the operators of a system has acquired through their experience can be logically described by the Linguistic Control Rule(LCR). The algorithm of th control is made of the LCR, and th control of an object is performed by processing this algorithm implementing a computer. in this thesis, the fuzzy controller of the ship's steering system is devided into two systems, namely FC1 and FC2, according to their control function. FC1 is for the course keeping steering, wheress FC2 is for the altering of s ship's course. The characteristics of the control system were investigated through the digital computer simulation and the results were compared with those of the conventional steering system. It was found that the fuzzy control was more efficient than the conventional auto pilot system.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.430-439
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• 2011

As the import and export cargos across the world increase with global trade environments, the ecocide caused lots of small marine organisms in the ship's ballast water is a big issue. The implementation of the BWTS (Ballast water treatment system) thus needs low-voltage high-current rectifier for electrolytic disinfection. So this paper proposes a suitable high-current inverter-type rectifier for electrolytic disinfection of seawater and analyzes its output characteristics. It also suggests the practical design guidelines for the proposed rectifier in terms of power circuit and controller designs.

• Journal of Power System Engineering
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• v.2 no.1
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• pp.73-79
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• 1998

In practical fields, the sway of crane systems leads to extra stress to the crane structure during the transporting operation and it is in close connection with its life. Usually, when we operate the cranes with high speed and manual control, the sway motion is irreducible. In this paper, a new type of crane system is proposed to avoid the irreducible sway of the crane systems. The proposed system is composed of mechanical arm with function of anti-sway based on conventional line system. By the anti-sway arm, we can realize to prevent the sway of the container box but cannot avoid the oscillation for the overall body of the crane. So, a controller design method to solve the above stated problem must be considered. The problem is solved by adopting the velocity pattern control methods of trapezoidal and curve types and its effectiveness is proved through experimental results.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.6
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• pp.562-567
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• 2000

Many pressure vessels for power and industrial plant are fabricated from low alloy carbon steels. The inner sides of pressure vessels are commonly weld-cladded with austenitic stainless steels to minimize problems of corrosive attack. Disbonding cracks are often detected at the transition region of welding interlayer, which is serious problem to reliability of pressure vessels. We have developed C-scan system to high speed inspection of overlay weld using DSP(digital signal processor). This system consists of signal processing parts (oscilloscope, pulser/receiver, digitizer, DSP), scanner, program and position controller. The developed system has been applied to a practical ultrasonic testing in overlay weld, and demonstrated high speed with precision

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1595-1601
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• 2018

The biggest obstacle to the commercialization of small and medium size microgrid (MG) is the reliability and economics of MG operation and maintenance. In this paper, we propose an autonomous operation method that is implemented as an application program installed in the MG operating system in emergency situations. The proposed algorithm consists of four steps of distinction, recognition, determination and control of emergency situations that can occur in MG. A fuzzy-based situation decision algorithm has been proposed to eliminate the barriers of autonomous operation in actual emergency situation such as occurrence of bad data and communication delay. In addition, countermeasures have been suggested for cases where multiple emergency situations have occurred in combination. The proposed algorithm was tested in a 500kW actual microgrid site of a university. Through the test, the validity of the proposed method and its applicability to practical MG operation are verified.

• Wind and Structures
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• v.32 no.1
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• pp.71-80
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• 2021

In steel cable bridges, the use of magnetorheological (MR) dampers between butt cables is constantly increasing to dampen vibrations caused by rain and wind. The biggest problem in the actual applications of those devices is to launch a kind of appropriate algorithm that can effectively and efficiently suppress the perturbation of the tie through basic calculations and optimal solutions. This article discusses the optimal evolutionary design based on a linear and quadratic regulator (hereafter LQR) to lessen the perturbation of the bridges with cables. The control numerical algorithms are expected to effectively and efficiently decrease the possible risks of the structural response in amplification owing to the feedback force in the direction of the MR attenuator. In addition, these numerical algorithms approximate those optimal linear quadratic regulator control forces through the corresponding damping and stiffness, which significantly lessens the work of calculating the significant and optimal control forces. Therefore, it has been shown that it plays an important and significant role in the practical application design of semiactive MR control power systems. In the present proposed novel evolutionary parallel distributed compensator scheme, the vibrational control problem with a simulated demonstration is used to evaluate the numerical algorithmic performance and effectiveness. The results show that these semiactive MR control numerical algorithms which are present proposed in the present paper has better performance than the optimal and the passive control, which is almost reaching the levels of linear quadratic regulator controls with minimal feedback requirements.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.271-281
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• 2022

Manual seed classification challenges can be overcome using a reliable and autonomous seed purity identification and classification technique. It is a highly practical and commercially important requirement of the agricultural industry. Researchers can create a new data mining method with improved accuracy using current machine learning and artificial intelligence approaches. Seed classification can help with quality making, seed quality controller, and impurity identification. Seeds have traditionally been classified based on characteristics such as colour, shape, and texture. Generally, this is done by experts by visually examining each model, which is a very time-consuming and tedious task. This approach is simple to automate, making seed sorting far more efficient than manually inspecting them. Computer vision technologies based on machine learning (ML), symmetry, and, more specifically, convolutional neural networks (CNNs) have been widely used in related fields, resulting in greater labour efficiency in many cases. To sort a sample of 3000 seeds, KNN, SVM, CNN and CNN-SVM hybrid classification algorithms were used. A model that uses advanced deep learning techniques to categorise some well-known seeds is included in the proposed hybrid system. In most cases, the CNN-SVM model outperformed the comparable SVM and CNN models, demonstrating the effectiveness of utilising CNN-SVM to evaluate data. The findings of this research revealed that CNN-SVM could be used to analyse data with promising results. Future study should look into more seed kinds to expand the use of CNN-SVMs in data processing.

• Journal of the Korea Safety Management & Science
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• v.23 no.4
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• pp.93-104
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• 2021

In this paper, we propose a method for diagnosing overload and working load of collaborative robots through performance analysis of machine learning algorithms. To this end, an experiment was conducted to perform pick & place operation while changing the payload weight of a cooperative robot with a payload capacity of 10 kg. In this experiment, motor torque, position, and speed data generated from the robot controller were collected, and as a result of t-test and f-test, different characteristics were found for each weight based on a payload of 10 kg. In addition, to predict overload and working load from the collected data, machine learning algorithms such as Neural Network, Decision Tree, Random Forest, and Gradient Boosting models were used for experiments. As a result of the experiment, the neural network with more than 99.6% of explanatory power showed the best performance in prediction and classification. The practical contribution of the proposed study is that it suggests a method to collect data required for analysis from the robot without attaching additional sensors to the collaborative robot and the usefulness of a machine learning algorithm for diagnosing robot overload and working load.