• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.1
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• pp.59-67
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• 2009

The purpose of this study is to provide a decision support to select an appropriate layered manufacturing(LM) machine that suits the application of a part. Selection factors include concept model, form/fit/functional model, pattern model far molding, material property, build time and part cost that greatly affect the performance of LM machines. However, the selection of a LM is not an easy decision because they are uncertain and vague. For this reason, the aim of this research is to propose hybrid multiple attribute decision making approaches to effectively evaluate LM machines. In addition, because subjective considerations are relevant to selection decision, a fuzzy logic approach is adopted. The proposed selection procedure consists of several steps. First, we identify LM machines that the users consider After constructing the evaluation criteria, we calculate the weights of the criteria by applying the fuzzy Analytic Hierarchy Process(AHP) method. Finally, we construct the fuzzy Technique of Order Preference by Similarity to Ideal Solution(TOPSIS) method to achieve the ranking order of all machines providing the decision information for the selection of LM machines.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.382-387
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• 2003

Many type of smart materials and control laws are available to actively adjust the structure from various external disturbances. Usually, a certain type of control law to activate a specific smart material is tell established, but the effectiveness of the control scheme is limited by the choice of the smart materials and the responses of the structure. ER fluid is adequate to provide small but arbitrary control forces at any point along the structure. It was found that active vibration control of the structure embedded with ER fluids fluidly to suppress the vibration excited with broad band frequency due to the limited change of the structure characteristics. To compensate this limited effect of the control scheme with ER fluid alone, PPF control using PZT as an actuator is added to construct a hybrid controller.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.154-161
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• 2009

In order to implement continuous-path motion on a robot, it is necessary to blend one joint motion to another joint motion near a via point in a trapezoidal form of joint velocity. First, the velocity superposition using parametric interpolation is proposed. Hybrid motion blending is defined as the blending of different two type's motions such as blending of joint motion with linear motion, in the neighborhood of a via point. Second, hybrid motion blending algorithm is proposed based on velocity superposition using parametric interpolation. By using a 3-axis SCARA (Selective Compliance Assembly Robot Arm) robot with $LabVIEW^{(R)}$ $controller^{(1)}$, the velocity superposition algorithm using parametric interpolation is shown to result in less vibration, compared with PTP(Point- To-Point) motion and Kim's algorithm. Moreover, the hybrid motion $algorithm^{(2)}$ is implemented on the robot using $LabVIEW^{(R)(1)}$ programming, which is confirmed by showing the end-effector path of joint-linear hybrid motion.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.34-39
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• 2008

In this study, CFRP(Carbon Fiber Reinforced Plastics) that has high specific strength and elastic modulus and low thermal strain was used as a material for the lightweight structural member. CFRP is a fiber material as anisotropic material. The anisotropic material is characterized by the change of its mechanical properties according to stacking orientation angle. CFRP orientation angle was oriented in [A/B]s in order to examine the effect of CFRP orientation angle on the characteristics of energy absorption. CFRP is very weak to the impact from the outside. So, when impact is applied to CFRP, its strength is rapidly lowered. The hybrid material was manufactured by combining CFRP to aluminum which is lightweight and widely used for structural members of the automobile. The hybrid member was shaped as a side member that could support the automobile engine and mount and absorb a large amount of impact energy at the front-end in case of automobile collision. The bending test device was manufactured in accordance with ASTM standard, and mounted to UTM for bending test. For comparing bending characteristics of the hybrid member with those of Aluminum and CFRP member, tests were performed for aluminum, CFRP and hybrid member, respectively.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.477-482
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• 2005

Recently, client computing trend has been changed from server oriented information application to network based P2P(Peer to Peer) services. The conventional client/server method has the merit of accessing abundant information, on the other side P2P has the merit of synchronized community support and information exchange. P2P has four meaning of point to point, peer to peer, person to person and path to profitability. In manufacturing system field, the second meaning is interested. P2P is classified to three type such as conventional client/server, hybrid P2P and pure P2P. The third is really peer to peer concept. The related technologies with P2P are P2P searching, XML, cooperation, IPv6, computing sharing and P2P communication. This paper describes the scheme of P2P and related contents. And through the P2P based technology, a P2P-based collaborative machine and a vertical portal machine are introduced in this paper. The scheme of the machines mentioned above is suggested for cooperation in manufacturing system and u-Manufacturing.

• Journal of Powder Materials
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• v.20 no.5
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• pp.355-358
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• 2013

Micro trench structures are applied in gratings, security films, wave guides, and micro fluidics. These micro trench structures have commonly been fabricated by micro electro mechanical system (MEMS) process. However, if the micro trench structures are machined using a diamond tool on large area plate, the resulting process is the most effective manufacturing method for products with high quality surfaces and outstanding optical characteristics. A nonferrous metal has been used as a workpiece; recently, and hybrid materials, including polymer materials, have been applied to mold for display fields. Thus, the machining characteristics of polymer materials should be analyzed. In this study, machining characteristics were compared between nonferrous metals and polymer materials using single crystal diamond (SCD) tools; the use of such materials is increasing in machining applications. The experiment was conducted using a square type diamond tool and a shaper machine tool with cutting depths of 2, 4, 6 and 10 ${\mu}m$ and a cutting speed of 200 mm/s. The machined surfaces, chip, and cutting force were compared through the experiment.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.765-767
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• 2001

Linear pulse Motors(LPM) are widely used in fields where smooth linear motion is required, and their position accuracy is higher than other motors. Hybrid linear pulse motors(HLPM) are regarded as an excellent solution to positioning problems that require high accuracy, rapid acceleration and high-speed. The LPM has low mechanical complexity, high reliability, precise open-loop operation and low inertia etc. in many application areas such as factory automation speed positioning, computer peripherals and numerically controlled machine tools. This motor drive system is especially suitable for machine tools the high position accuracy and repeatability. This paper describes about that need of the embroider machine, we want to design position-scanning device for the embroidery machine. At first, to be analysed characteristics of the machine and next designed the LPM. we used the field analysis program, The finite element method(FEM) program tool is employed for calculation the force. The reluctance models will be used the magnetic permeance of air gap by static- conditions. The forces between forcer and platen have been calculated using the virtual work method.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.91-93
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• 2001

Linear pulse Motors(LPM) are widely used in fields where smooth linear motion is required, and their position accuracy is higher than other motors. Hybrid linear pulse motors(HLPM) are regarded as an excellent solution to positioning problems that require high accuracy, rapid acceleration and high-speed. The LPM has low mechanical complexity, high reliability, precise open-loop operation and low inertia etc. In many application areas such as factory automation speed positioning, computer peripherals and numerically controlled machine tools, LPM can be used. This motor drive system is especially suitable for machine tools the high position accuracy and repeatability. This paper describes about that need of the embroider machine, we want to design position-scanning device for the embroidery machine. At first, to be analysed characteristics of the machine and next designed the LPM, we used the field analysis program. The finite element method(FEM) program tool is employed for calculation the force. The reluctance models will be used the magnetic permeance of air gap by static-conditions. The forces between forcer and platen have been calculated using the virtual work method. And we used the simulink to know the dynamic characteristics of LPM.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3423-3440
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• 2023

In this work, a multivariate time-series machine learning meta-model is developed to predict the transient response of a typical nuclear power plant (NPP) undergoing a steam generator tube rupture (SGTR). The model employs Recurrent Neural Networks (RNNs), including the Long Short-Term Memory (LSTM), Gated Recurrent Unit (GRU), and a hybrid CNN-LSTM model. To address the uncertainty inherent in such predictions, a Bayesian Neural Network (BNN) was implemented. The models were trained using a database generated by the Best Estimate Plus Uncertainty (BEPU) methodology; coupling the thermal hydraulics code, RELAP5/SCDAP/MOD3.4 to the statistical tool, DAKOTA, to predict the variation in system response under various operational and phenomenological uncertainties. The RNN models successfully captures the underlying characteristics of the data with reasonable accuracy, and the BNN-LSTM approach offers an additional layer of insight into the level of uncertainty associated with the predictions. The results demonstrate that LSTM outperforms GRU, while the hybrid CNN-LSTM model is computationally the most efficient. This study aims to gain a better understanding of the capabilities and limitations of machine learning models in the context of nuclear safety. By expanding the application of ML models to more severe accident scenarios, where operators are under extreme stress and prone to errors, ML models can provide valuable support and act as expert systems to assist in decision-making while minimizing the chances of human error.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.379-384
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• 2000

The reactive and harmonic current components of dc loads can be compensated by the three-phase hybrid power filter (HPF) system. After compensation, the resulting current has sinusoidal and in-phase components with the source voltage. The HPF system is constructed by an active filter and passive filters. The passive filter reduce the 5th and 7th harmonic of the load current. The active filter compensates the remainder of the load current. Using the HPF system, a low cost harmonic compensator can be made. Performance of the HPF system is verified through simulation,