• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.1
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• pp.84-91
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• 2013

Ultrasonic flip-chip bonding needs a precise bonding tool which delivers ultrasonic energy into chip bumps effectively to use the selected resonance mode and frequency of the horn structure. The bonding tool is excited at the resonance frequency and the input and output ports should locate at the anti-nodal points of the resonance mode. In this study, we propose new design method with topology optimization for ultrasonic bonding tools. The SIMP(solid isotropic material with penalization) method is used to formulate topology optimization and OC(optimal criteria) algorithm is adopted for the update scheme. MAC(modal assurance criterion) tracking is used for the target frequency and mode. We fabricate two prototypes of ultrasonic tools which are based on 3D optimization models after reviewing 2D and 3D topology optimization results. The prototypes are satisfied with the ultrasonic frequency and vibration amplitude as the ultrasonic bonding tools.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.247-249
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• 2003

Currently there are a variety of different tools may be used to analyze, model, describe and document a business process. However, it is difficult to exchange the information of a business process created in different tools because of the distinct information formats used in different tools. The XML Process Definition Language (XPDL) of the Workflow Management Coalition (WfMC) forms a common interchange standard that enables products to continue to support arbitrary internal representations of process definitions with an import/export function to map to/from the standard at the product boundary. Generally a business process model can be represented by the UML activity diagram, but there is a difficult task to directly generate an XPDL document from a business process model represented by the standard activity diagram. In the paper we will propose an approach to generate an XPDL document from a business process model represented by the extended UML activity diagram.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.243-246
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• 2000

Software Engineering covers techniques, tools, and methodologies needed to develop, acquire, and manage software in high quality, using appropriate resources. Therefore it can be said that the administration target of software engineering activities is the pursuit of high productivity for production of software in good quality. To do this, they should establish the engineering principle based on engineering theory and concept, and form the effective environment of engineering technology through improving development methods/methodology and tools of software engineering. In addition several guidances related to information system planning, acquisition, development, management, maintenance, and evaluation, etc. must be invented on the basis of software engineering to encourage efficiency of public information business yearly increasing fastand to make sure compatibility and interoperability.

• Construction Engineering and Management
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• v.6 no.6 s.28
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• pp.25-26
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• 2005

• Computational Structural Engineering
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• v.35 no.1
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• pp.4-10
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• 2022

• Journal of Engineering Education Research
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• v.21 no.5
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• pp.10-19
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• 2018

The need for integrating the arts and literature into the engineering education has been emphasized to cultivate the creative talent in recent years. However, there have been few studies to investigate how the arts and literature can be linked with nurturing creative talent in the engineering fields. In this paper, it is examined that inventive thinking principles for creative ideation in the engineering fields can be applied to the arts and literature. For the purpose, creative works in the arts and literature, which can be explained by the five thinking tools of SIT(Systematic Inventive Thinking), are collected. The result shows that engineering and the arts share common thinking patterns.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.161-167
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• 2020

In the process of cutting large aircraft parts, the tool may be abnormally worn or damaged due to various factors such as mechanical vibration, disturbances such as chips, and physical properties of the workpiece, which may result in deterioration of the surface quality of the workpiece. Because workpieces used for large aircrafts parts are expensive and require strict processing quality, a maintenance plan is required to minimize the deterioration of the workpiece quality that can be caused by unexpected abnormalities of the tool and take maintenance measures at an earlier stage that does not adversely affect the machining. In this paper, we propose a method to indirectly monitor the tool condition that can affect the machining quality of large aircraft parts through real-time monitoring of the current signal applied to the spindle motor during machining by comparing whether the monitored current shows an abnormal pattern during actual machining by using this as a reference pattern. First, 30 types of tools are used for machining large aircraft parts, and three tools with relatively frequent breakages among these tools were selected as monitoring targets by reflecting the opinions of processing experts in the field. Second, when creating the CNC machining program, the M code, which is a CNC auxiliary function, is inserted at the starting and ending positions of the tool to be monitored using the editing tool, so that monitoring start and end times can be notified. Third, the monitoring program was run with the M code signal notified from the CNC controller by using the DAQ (Data Acquisition) device, and the machine learning algorithms for detecting abnormality of the current signal received in real time could be used to determine whether there was an abnormality. Fourth, through the implementation of the prototype system, the feasibility of the method proposed in this paper was shown and verified through an actual example.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1006-1011
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• 2004

Recently, technical trend in machine tools is focused on enhancing of speed, accuracy and reliability. Such high speed usually results in thermal displacement and structural deformation. To minimize such thermal effect, most precision machine tools adopt high precision cooling system. This study proposes a temperature control for an oil cooler system using PI control with fuzzy logic. In a cooler system, the refrigerant flow rate is controlled by rotational speed of the compressor, where the outlet oil temperature is selected as the control variable. The fuzzy control rules iteratively correct PID parameters to minimize the error, difference between the outlet temperature and the reference one. Here, the ambient temperature is used as the reference one. To show the effectiveness of the proposed method, a series of experiments are conducted for an oil cooler system of machine tools, and the results are compared with the ones of a conventional PID control. The experimental results show that the proposed method has advantages of smaller overshoot and smaller steady state error.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.403-410
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• 2020

Continuous industrial development has led to a better quality of life for everyone, even further accelerating industrial growth. Industrial development, however, has also caused environmental degradation, which is posing a serious threat to humanity. It has also encouraged the indiscriminate use of limited resources, causing resource depletion. Efficient resource management based on resource circulation is critical to saving resources. Resource circulation methods are as follows: reducing the use of resources in the manufacturing process, recycling used or reprocessed products and reusing used resources without being reprocessed, remanufacturing with end-of-life products with disassembled parts. Furthermore, remanufacturing process including cleaning, inspection, repairing, and reassembling facilitate performance level as well as new typical products. It is noteworthy that the remanufacturing of machine tools can significantly save resources because their structural parts are substantially large in size. Machine tools have served as a foundation for the manufacturing industry, which has driven Korea's industrial development. Nevertheless, a few research has been reported for remanufacturing technology with used machine tools. Relevant research of developing a remanufacturing process chart and method is prerequisite for saving the resource and environments.

• BMB Reports
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• v.57 no.1
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• pp.30-39
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• 2024

Directed evolution (DE) of desired locus by targeted random mutagenesis (TRM) tools is a powerful approach for generating genetic variations with novel or improved functions, particularly in complex genomes. TRM-based DE involves developing a mutant library of targeted DNA sequences and screening the variants for the desired properties. However, DE methods have for a long time been confined to bacteria and yeasts. Lately, CRISPR/Cas and DNA deaminase-based tools that circumvent enduring barriers such as longer life cycle, small library sizes, and low mutation rates have been developed to facilitate DE in native genetic environments of multicellular organisms. Notably, deaminase-based base editing-TRM (BE-TRM) tools have greatly expanded the scope and efficiency of DE schemes by enabling base substitutions and randomization of targeted DNA sequences. BE-TRM tools provide a robust platform for the continuous molecular evolution of desired proteins, metabolic pathway engineering, creation of a mutant library of desired locus to evolve novel functions, and other applications, such as predicting mutants conferring antibiotic resistance. This review provides timely updates on the recent advances in BE-TRM tools for DE, their applications in biology, and future directions for further improvements.