• Smart Structures and Systems
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• v.14 no.2
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• pp.129-144
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• 2014

In this paper, a fuzzy inference system and an analytical hierarchy process-based online evaluation technique is developed to monitor the condition of the 32-km Donghai Bridge in Shanghai. The system has 478 sensors distributed along eight segments selected from the whole bridge. An online evaluation subsystem is realized, which uses raw data and extracted features or indices to give a set of hierarchically organized condition evaluations. The thresholds of each index were set to an initial value obtained from a structure damage and performance evolution analysis of the bridge. After one year of baseline monitoring, the initial threshold system was updated from the collected data. The results show that the techniques described are valid and reliable. The online method fulfills long-term infrastructure health monitoring requirements for the Donghai Bridge.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.30-35
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• 2003

Recently, with the rapid growth of information technology, many studies have been performed to implement web-based manufacturing system. Such technologies are expected to meet the need of many manufacturing industries those want to adopt E-manufacturing system for the construction of globalization, agility, digitalization to cope with the rapid changing market requirements. In this research, areal-time web-based machine tool and machining process monitoring system is developed as a first step fur implementing I-manufacturing system. In this system, main spindle motor current and feed current are measured using hall sensors. And the relationship between the cutting force and the spindle motor RMS current at various spindle rotational speed is obtained. Also, a rule-based expert system is developed in order to monitor the machining process effectively. Finally, developed system is applied to real machining process to verify the effectiveness.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.107-118
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• 2013

In this paper, we developed the semiconductor monitoring system for the etching process. Around the world, expert companies are competing fiercely since the semiconductor industry is a leading value-added industry that produces the essential components of electronic products. As a result, many researches have been conducted in order to improve the quality, productivity, and characteristics of semiconductor products. Process monitoring techniques has an important role to give an equivalent quality and productivity to produce semiconductor. In fact, since the etching process to form a semiconductor circuit causes great damage to the semiconductors, it is very necessary to develop a system for monitoring the process. The proposed monitoring system is mainly focused on the dry etching process using plasma and it provides the detailed observation, analysis and feedback to managers. It has the functionality of setting scenarios to match the process control automatically. In addition, it maximizes the efficiency of process automation. The result can be immediately reflected to the system since it performs real-time monitoring. UI (User Interface) provides managers with diagnosis of the current state in the process. The monitoring system has diverse functionalities to control the process according to the scenario written in advance, to stop the process efficiently and finally to increase production efficiency.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1245-1251
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• 2013

This study has focused on development of ELID monitoring system and its application to ELID grinding of structural ceramics. ELID monitoring system was consisted of grinding equipment, ELID power supply, grinding wheel, electrode and monitoring program. It can give a real time data to check spindle grinding resistance, wheel revolution, dressing current and voltage in ELID grinding process. The performance of developed system was evaluated by applying to grinding of structural ceramics, silicon carbide and alumina. As the results of experiments, monitored data for spindle resistance and ELID dressing current was useful to check steady-state ELID grinding process. From the comparison of spindle resistance between ELID grinding and conventional grinding process according to change of depth of cut, it could be confirmed that the spindle resistance in ELID grinding was lower than conventional grinding process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.5
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• pp.397-401
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• 2008

Most of the topic in PCB industry was about increasing the volume of product for the development of electronics in numerous industrial application area. However, it has been emerged that yield improvement quality manufacturing via detecting any suspicious process in order to minimize the scrapped product and material waste. In addition, recently, restriction of hazardous substances (RoHS) claims that electronic manufacturing environment should reduce the harmful chemicals usage, thus the importance of monitoring copper etchant and detecting any mis-processing is crucial for electronics manufacturing. In this paper, we have developed real-time chemical monitoring system using RGB sensor, which is simpler but more accurate method than commercially utilized oxidation reduction potential (ORP) technique. The developed Cu etchant monitoring system can further be utilized for copper interconnect process in future nano-semiconductor process.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.109-117
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• 2005

In case of fine machining processes, the cutting state monitoring by a skilled operator is impossible because the physical changes generated during fine machining are very weak. To realize the high efficient and precise fine machining, it is necessary to develop the sensor based monitoring system which is able to detect the fine changes of cutting state. In this paper, the fine acoustic emission monitoring system is developed to monitor the state of the fine machining process. The developed system consists of the AE sensor and the AE signal processing unit. And this has the high-sensitivity and bandwidth which can detect fine AE signal generated during fine machining process. In order to investigate the feasibility of the developed system, evaluation experiments were performed in the fine fixed-abrasive machining processes such as polishing and glass ferrule slicing. Experimental results show that the developed monitoring system possesses an excellent real-time monitoring capability at fine machining processes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.95-98
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• 2002

Monitoring of the cutting trouble is necessarily required to do Factory Automation and Intelligent manufacturing system. Therefore, we constructed a monitoring system using neural network in order to monitor of the cutting trouble. From obtained result, it is shown that the cutting trouble can be monitored effectively by neural network

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.1-6
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• 2015

Tool condition monitoring plays one of the most important roles in the improvement of both machining quality and productivity. In this regard, various process signals and monitoring methods have been developed. However, most of the existing studies used cutting force or acoustic emission signals, which posed risks of interference with the machining system in dynamics, fixturing, and machining configuration. In this study, a feed motor current signal is used as a process signal representing process and tool states in tool breakage monitoring based on an adaptive autoregressive model and unsupervised neural network. From the experimental results using various cases of tool breakage, it is shown that the developed system can successfully detect tool breakage before two revolutions of the spindle after tool breakage.

• Journal of Environmental Impact Assessment
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• v.9 no.2
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• pp.119-126
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• 2000

Environmental monitoring system has been adopted and supplemented as inspection measures for the quantitative and qualitative changes of environmental impact assessment (EIA). Meanwhile it has been continuously pointed out that there is insufficient connection between environmental monitoring system and EIA. Often the agreed environmental impact assessment has not been fulfilled due to the argument of the cost, timing and situations of construction sites. Thus the purpose of this study is in search of the rationalized environmental monitoring system in order to harmonize the development and environmental conservation through the improvement of unreasonable aspects of the current EIA execution process. As to comply with the purpose, this research was carried out with three different but complimentary sources: environmental laws and regulations, foreign case studies of Japan, U.S.A. and Canada, and interviews with 73 experts. Finally, improved environmental monitoring system has been introduced reflecting the present process of EIA.

• Laser Solutions
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• v.4 no.2
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• pp.29-38
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• 2001

A development of in-process and reliable monitoring system in laser materials processing is essential for successful applications toward the real industrial fields. It was known that optical signals induced by laser-matter interactions provide a good indication not only to monitor various defects but also to characterize and identify the process However there are still difficulties to implement the optical monitoring system in real fields since the system is susceptible to the spurious change of the signal affected by the variation of experimental conditions and environmental noises. In this article. a new type of optical monitoring technique named 'chromatic modulation technique' is described as a reliable, robust and sensitive monitor for the applications in laser materials processing in order to tackle the conventional problems in optical system.