• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.2
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• pp.79-85
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• 2020

IIoT stands for Industrial Internet of Things used in manufacturing, healthcare, and transportation in networked smart factories. Recently, IIoT's environment requires an automated control system through intelligent cognition to improve efficiency. In particular, IIoT can be applied to automatic calibration of production equipment for improved management in industrial environments. Such automation systems require a wireless network for transmitting industrial data. Self-calibration systems in laser transmission paths using wireless networks can save resources and improve production quality by real-time monitoring and remote control of laser transmission path. In this paper, we propose a wireless networked system for self-calibration of laser equipment that requires a laser transmission path, and we show the results of the prototype evaluation. The self-calibration system of laser equipment measures the coordinates of the laser points with sensors and sends them to the host using the proposed application protocol. We propose a wireless network service for the wired motor controller to align the laser coordinates. Using this wireless network, the host controls the motor by sending a control command of the motor controller in an HTTP message based on the received coordinate values. Finally, we build a prototype system of the proposed design to verify the detection performance and analyze the network performance.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.5
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• pp.389-394
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• 2014

In this paper, we report a new manufacturing method for friction reduction using micro-AAJ (abrasive air-jet) machining. AAJ machining employs compressed air to accelerate a jet of high-speed particles to mechanically machine features, including micro-channels and micro-holes, into glass, metal, or polymer substrates for use in microfluidics, MEMS (micro electromechanical systems). And we introduce the micro-AAJ machining system, which consists of a micro-AAJ nozzle and a five-axis positioning system. Various micro-AAJ nozzles can be used, depending on the required surface structure, and three-dimensional machining is possible. We machined samples under six different conditions and describe machining results obtained while using it. We also measured the coefficient of friction of micro-textured surfaces. We report the coefficient of friction of micro-textured surfaces patterned using micro-AAJ machining for engine piston ring.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.43-46
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• 2010

전력산업분야는 스마트그리드 표준체계 및 고도화된 정보통신 인프라의 도입과 보안 그리고 분산전력 등에 대한 신기술 도입에 의해서 급격한 변화기를 맞이하고 있다. 현재 미국과 EU에서는 세계시장을 겨냥해서 스마트그리드의 국제표준화를 주도하고 있으며, 제3세계에서는 전력설비 시장의 지속적 성장이 예상되고 있다. 이에 국내에서도 국제 경쟁력 확보 및 신성장동력 창출을 목표로 연구가 진행 중이다. 전력체계의 운영망과 별개의 시험망 구성이 필요하며, 그 시험망을 통한 검증을 위해 시험망내 표준규격의 통신환경의 설계 및 기능검증은 매우 중요한 요소이다. 본 논문에서는 시험평가망 구성이후 평가를 위해 사용할 수 있는 주요 Component의 설계과정 중의 일부인 IEC 61850기반의 MMS 통신 환경구성 및 기능검증을 위한 연구결과에 대해 설명한다.

• Journal of Distribution Science
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• v.11 no.7
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• pp.47-56
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• 2013

Purpose - In the academic literature, the researches on a comparative study on purchase behaviors of the consumers from emerging and mature markets remain limited. Therefore, this empirical study is attempted to examine the effects of country of origin (COO), brand image and corporate image on the purchase behavior of Chinese consumers (as from emerging market) and Korean consumers (as from mature market). Research Design, data, methodology - In total, 615 valid questionnaires were collected from the main cities of China and Korea respectively, and a multiple group analysis was conducted to test the hypotheses with SPSS 16.0 and AMOS18.0. Results - Chinese consumers are not influenced by country-of-origin effect, whereas Korean consumers are sensitive to it. Both Chinese and Korean consumers are sensitive to brand image, whereas corporate image does appear to influence Chinese consumers but not Korean consumers. The effects of country-of-origin are not more influential in less developed market (China) than more developed market (Korea). Conclusions - According to the results of this empirical study, the country-of-origin effect does impact Korean consumers but not Chinese consumers' purchase behavior. Therefore, multinational companies are relatively free to make the decision, if Chinese consumers are the marketing targets, when choosing manufacturing sites.

• Smart Structures and Systems
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• v.20 no.6
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• pp.669-682
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• 2017

The normalised version of bispectrum, the so-called bicoherence, has often proved a reliable method of damage detection on engineering applications. Indeed, higher-order spectral analysis (HOSA) has the advantage of being able to detect non-linearity in the structural dynamic response while being insensitive to ambient vibrations. Skewness in the response may be easily spotted and related to damage conditions, as the majority of common faults and cracks shows bilinear effects. The present study tries to extend the application of HOSA to damage localisation, resorting to a neural network based classification algorithm. In order to validate the approach, a non-linear finite element model of a 4-meters-long cantilever beam has been built. This model could be seen as a first generic concept of more complex structural systems, such as aircraft wings, wind turbine blades, etc. The main aim of the study is to train a Neural Network (NN) able to classify different damage locations, when fed with bispectra. These are computed using the dynamic response of the FE nonlinear model to random noise excitation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.510-514
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• 2020

Vocational education needs to be transformed to cultivate talents with diverse fusion competencies, which is in line with the recent changes that have become a part of the complex technological developments in the 4th Industrial Revolution. Therefore, it is very important for college graduates to obtain employment skills as they are required to prepare for careers within the complex environments of future societies. With the transition to the Internet of Things (IoT)-based control in the manufacturing industry, the development of technological education and related training programs is required to cultivate practical talents for students who have acquired not only the information on existing programmable logic controller (PLC)-based technology, but also that on embedded programming technology. Therefore, to develop an NCS-based education program for analog signal processing to ensure that programming can easily be learned for cultivating practical talent, this study summarizes the opinions of field experts, selects the appropriate NCS competency unit, and designs an adequate technology education training program.

• Transactions of Materials Processing
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• v.7 no.6
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• pp.545-553
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• 1998

The purpose of this paper is to develop a CAD/CAM system for generation of designing and manufacturing information such as total drawing sub-assembly drawing, part drawing detail drawing part list and NC data for machining by CNC lathe were CUT machining center. Through this study the CAD/CAM system for deep drawing transfer die in mechanical press process has been developed The developed CAD system can generate the drawings of transfer die in mechanical press. Using these results from CAD system. it can generate NC data to machine die's elements on the CAD system. This system can reduce design man-hours and human errors. In order to construct the system it is used to automate the design process using knowledge base system. The developed system is based on the knowledge base system which is involved a lot of expert's empirical knowhow in the practice field. Using AutoLISp language under the Auto CAD system. CTK customer language of SmartCAM is used as the overall CAD/CAM environment. Results of this system will be provide effective aids to the designer and manufacturer in this field

• The Journal of Asian Finance, Economics and Business
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• v.8 no.10
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• pp.361-371
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• 2021

This research aims to analyze the effects of managerial overconfidence and corporate governance on investment decisions. Besides, it also tries to discover the effect of internal financing mediation between managerial overconfidence and corporate governance on investment decisions. This study employed panel data from 44 manufacturing companies from 2014 to 2019, out of a total of 117, thus the total observations are 264. The hypothesis was verified through structural equation modeling (Smart PLS 2). The study revealed as follows: 1) Managerial overconfidence has a positive and significant effect on internal financing, while corporate governance has a negative and significant effect on internal financing, 2) managerial overconfidence, internal financing, and corporate governance have a positive and significant effect on investment decisions, 3) internal financing partially mediated the effect of managerial overconfidence on investment decisions, However, internal financing does not mediate the effect of corporate governance on investment decisions. The findings in this study will help company managers implement good corporate governance to improve investment efficiency. In addition, managers can reduce the proportion of retained earnings and increase the proportion of dividend payout ratios, and increase the use of external sources of funds in making investments to minimize agency costs and manager's opportunistic behavior.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.117-124
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• 2021

The development of IOT technology and artificial intelligence technology is promoting the smartization of manufacturing system. In this study, data extracted from acceleration sensor and current sensor were obtained through experiments in the cutting process of SKD11, which is widely used as a material for special mold steel, and the amount of tool wear and product surface roughness were measured. SVR (Support Vector Regression) is applied to predict the roughness of the product surface in real time using the obtained data. SVR, a machine learning technique, is widely used for linear and non-linear prediction using the concept of kernel. In particular, by applying GSVQR (Generalized Support Vector Quantile Regression), overestimation, underestimation, and neutral estimation of product surface roughness are performed and compared. Furthermore, surface roughness is predicted using the linear kernel and the RBF kernel. In terms of accuracy, the results of the RBF kernel are better than those of the linear kernel. Since it is difficult to predict the amount of tool wear in real time, the product surface roughness is predicted with acceleration and current data excluding the amount of tool wear. In terms of accuracy, the results of excluding the amount of tool wear were not significantly different from those including the amount of tool wear.

• Smart Structures and Systems
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• v.23 no.3
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• pp.227-242
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• 2019

Seismic isolation systems employ structural control that protect both buildings and vibration-sensitive contents from destructive effects of earthquakes. Structural control is divided into three main groups: passive, active, and semi-active. Among them, semi-active isolation systems, which can reduce floor displacements and accelerations concurrently, has gained importance in recent years since they don't require large power or pose stability problems like active ones. However, their seismic performance may vary depending on the variations that may be observed in the mechanical properties of semi-active devices and/or seismic isolators. Uncertainties relating to isolators can arise from variations in geometry, boundary conditions, material behavior, or temperature, or aging whereas those relating to semi-active control devices can be due to thermal changes, inefficiencies in calibrations, manufacturing errors, etc. For a more realistic evaluation of the seismic behavior of semi-active isolated buildings, such uncertainties must be taken into account. Here, the probabilistic behavior of semi-active isolated buildings under historical pulse-like near-fault earthquakes is evaluated in terms of their performance in preserving structural integrity and protecting vibration-sensitive contents considering aforementioned uncertainties via Monte-Carlo simulations of 3-story and 9-story semi-active isolated benchmark buildings. The results are presented in the form of fragility curves and probability of failure profiles.