• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.6 no.3
• /
• pp.36-43
• /
• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for tool wear and breakage during turning operation. Developing economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. The validity of the proposed system is confirmed through the large number of cutting tests.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.4
• /
• pp.37-45
• /
• 2010

A system which needs timely accuracy has to design and to verify correctly about execution-time for reliability. Accordingly, it is necessary for timing analysis tools, and much previous research worked. In timing analysis tool, there are two methods. One is a static analysis, and the other is a measurement based analysis. A static analysis is able to spend time less than a measurement based analysis method, but has low reliability of analysis result caused by hard to estimate time of I/O caused by various hardware. A measurement based analysis can be close analysis to real result, but it is hard to adapt to actual application, and spend a lot of time to get result of analysis. As such, this paper present a software monitoring architecture to supply reliability of static analysis process. In a presented architecture, it can select target as needed measurement through static analysis, and reuse result of measurement exist. Therefore, The architecture can reduce overload of time and performance for measurement, and improve the reliability which is the worst problem of static analysis.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.6
• /
• pp.776-785
• /
• 2011

Since the Internet-based real-time Global Positioning System(GPS) synchronized widearea power system frequency monitoring network (FNET) was proposed in 2001, it has been monitoring the power system frequency in interconnected United States power systems and numerous interesting behaviors have been observed, including frequency excursion propagation. We address the consistency of a frequency excursion detection order of frequency disturbance recorders in FNET in relation to the same generation trip, as well as the ability to recreate by power systems dynamic simulation. We also propose a new method, as an application of FNET measurement, to locate a tripped generator using power systems dynamic simulation and wide-area frequency measurement. The simulation database of all the possible trips of generators in the interconnected power systems is created using the off-line power systems dynamic simulation. When FNET detects a sudden drop in the monitoring frequency, which is most likely due to a generation trip in power systems, the proposed algorithm locates a tripped generator by finding the best matching case of the measured frequency excursion in the simulation database in terms of the frequency drop detection order and the time of monitoring points.

• Journal of the Korean Society for Railway
• /
• v.5 no.3
• /
• pp.148-157
• /
• 2002

A health monitoring system becomes a useful tool to obtain information on long term behavior of the important railway structures such as very long span and special type bridges. The health monitoring system not only gives the direct measurement data of the railway bridges but also provides the basic data on the maintenance of the structures. Therefore, periodic calibrations of the health monitoring system will be a necessary step toward precise and accurate assessment of the railway bridges. In this study, the calibration and gauge factor readjustment process made for the health monitoring system installed in the railroad bridges is reviewed and some findings are explained in detail: specifically, the calibrators made for this purpose are illustrated and the regression processes of the calibration on long-term displacement using water level sensor, longitudinal displacement using LVDT sensor, instantaneous displacement using LVDT sensors and accelerometer are described in full length. Based on the regression results, it was found that the gauge factors need to be readjusted according to the regression equation but, since the deviation or shift is not serious so far, long-term observation on each sensor is also recommended. Future work will be concentrated on the long-term analysis of each sensor and on the database creation so that the assessment of the structures is possible.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.11
• /
• pp.1879-1884
• /
• 2007

In the electric power industry, it is important that the supply of energy must be guaranteed. Many power utilities control and supervise the transmission line to avoid power failures. In case of underground tunnel, some troubles are reported in cable joint. To stabilize the power, it is needed to monitor the cable joint. Many researches of cable joint monitoring have been going on by partial discharge measurement and temperature measurement using optical cable. These methods need much cost to install and maintain, so it is only used in critical transmission line. In this research, we use wireless sensor technology, because of its low cost and easy installation. We develop the temperature monitoring system for cable joint. Temperature sensor is installed on the surface of cable joint and sends data to server through router node using wireless network. Generally Ad hoc routing is searched in wireless network. However, in this research, we design the static linear routing mechanism, which is suitable for electric power line monitoring and analyze the life time of the sensor node by measuring the amount of the battery consumption.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.6
• /
• pp.527-533
• /
• 2003

Recently, need of power stability and reliability has been increased as the spread of the sensitive electronic loads. Therefore, the power quality(PQ) problems become the hot Issue of public interest in these days. Many kinds of algorithms have been studied for the monitoring of PQ problems using the monitoring algorithms with RMS or FFT scheme, but it is still not enough to measure all of the PQ problems. This paper proposed the application of discrete wavelet transform(WT) for the PQ problems monitoring with the Introduction of WT theory, and the design of PQ monitoring data acquisition system Is described with some experimental results to verify the validity of the proposed PQ monitoring algorithm.

• Journal of the Semiconductor & Display Technology
• /
• v.22 no.1
• /
• pp.1-5
• /
• 2023

Most of the production process is performed in a cleanroom in the case of facilities that produce semiconductor chips or display panels. Therefore, environmental management of cleanrooms is very important for product yield and quality control. Among them, airborne particles are a representative management item enough to be the standard for the actual cleanroom rating, and it is a part of the Fab or Facility monitoring system, and the sequential particle monitoring system is mainly used. However, this method has a problem in that measurement efficiency decreases as the length of the sampling tube increases. In addition, a statistically significant test of deterioration in efficiency has rarely been performed. Therefore, in this study, the statistically significant test between the number of particles measured by InSitu and the number of particles measured for each sampling tube ends(Remote). Through this, the efficiency degradation problem of the sequential particle monitoring system was confirmed by a statistical method.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1324-1327
• /
• 2009

Social infrastructure is the basis of public welfare and should be recognized and managed as important assets. Bridge is one of the most important infrastructures to be managed systematically because the impact of the failure is critical. It is essential to monitor the performance of bridges in order to manage them as an asset. But current analytical methods such as predictive modeling and structural analysis are very complicated and difficult to use in practice. To apply these methods, structural and material condition data collection should be performed in each element of bridge. But it is difficult to collect these detailed data in large numbers and various kinds of bridges. Therefore, it is necessary to collect data of major measurement items and predict the life of bridges roughly with advanced information technologies. When certain measurement items reach predefined limits in the monitoring bridges, precise performance measurement will be done by detailed site measurement. This paper describes the selection of major measurement items that can represent the tendency of bridge life and introduces automated bridge data collection test-bed using wireless sensor network technology. The following will be major parts of this paper: 1) Examining the features of conventional bridge management system and data collection method 2) Mileage concept as a bridge life indicator and measuring method of the indicator 3) Test-bed of automated and real-time based bridge life indicator monitoring system using wireless sensor network

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1305-1312
• /
• 2006

This study is about the development of measurement system using ubiquitous wireless communication for river flow monitoring. The system can acquire water depth, quality (temperature, pH, conductivity, turbidity etc.) while a GPS module for getting the location data of measurement points. Also this system is able to acquire the field data via RF connection and can be controlled same time. The acquired data is transmitted to a gateway system from the remote buoy using Zigbee wireless connection. And the gateway system is able to monitor the data through GIS monitoring tool. Finally the data are transmitted to a server computer using CDMA wireless connection by gateway system. The D/B of server computer are constructed automatically and monitored the project web site. The resulting system can be used for scour monitoring, environment monitoring and the other monitoring purposes such as a river flow monitoring system.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.27 no.2
• /
• pp.105-114
• /
• 2017

Objectives: The Ministry of Employment and Labor's enforcement programs, such as workplace monitoring inspection, are one of the major public efforts to protect worker's health. Therefore, a more effective inspection method is required for workplace monitoring, which is helpful for controlling health hazards in the workplace. Methods: For this study, we investigated the related safety and health laws, regulations, and inspection guidelines from the USA, Japan, and Korea. We also analyzed the provisions of industrial safety and health acts, which are related to enhancing the reliability of workplace monitoring. We applied the process of opinion convergence through an experts meeting for our research. Results: We proposed an efficient inspection scheme for workplace monitoring that includes how to select companies(mainly randomized inspections by using a workplace measurement database and workers' compensation insurance database), how to proceed with the inspection process(mainly unannounced visits), and who should carry out this project. Conclusions: We conclude that our proposal for the inspection of workplace monitoring could be a very effective tool for reducing the numbers of companies that do not undertake workplace monitoring and could produce reliable monitoring results.