• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.143-148
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• 2013

In FMEA, occurrence and detectability are not related to only failure modes itself but also their causes. It is assumed that any failure occurs after at least one cause corresponding to failure occurs in advance. Occurrence of the failure mode is described by occurrence time of its cause and elapsed time to the actual failure. Under the periodic monitoring plan, the monitoring interval is another factor to determine the detectability and occurrence of each failure mode. When a failure cause occurs, the failure does not occur if the cause is identified and remedied before it actually occurs. Under this situation, we construct an economic model for prioritizing failure modes. The loss function is based on the unfulfilled mission period. We also provide an optimal monitoring plan with an illustrative example.

• Journal of the Korean association of regional geographers
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• v.10 no.1
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• pp.177-191
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• 2004

Monitoring has been done for the shingle beach in Hagdong Beach in Geojesi, City during the seven month period. The shingle beach has been found to go through the cyclic change according to the tidal schedule. The typhoon Rusa in year 2002 affected whole beach face. Sea wall, constructed to protect the village along the beach, aggravates the situation, since it cut off the supply of shingle from the marine terrace, upon which village was built. Concrete walls along the streams also diminish the supply of shingles from the mountains. To protect the shingle beach and encourage the sustainable eco-tourism long-term monitoring on sediment budget is necessary.

• Journal of Computing Science and Engineering
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• v.2 no.2
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• pp.180-199
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• 2008

Technology has had a tremendous impact on our daily lives. Recently, technology and its impact on aging has become an expanding field of inquiry. A major reason for this interest is that the use of technology can help older people who experience deteriorating health to live independently. In this paper we give a brief review of the in-home monitoring technologies for the elderly. In the pilot study, we analyze the possibility of employing the data generated by a continuous, unobtrusive nursing home monitoring system for predicting elevated(abnormal)pulse pressure(PP) in elderly(PP=systolic blood pressure-diastolic blood pressure). Our sensor data capture external information(behavioral) about the resident that is subsequently reflected in the predicted PP. By continuously predicting the possibility of elevated pulse pressure we may alert the nursing staff when some predefined threshold is exceeded. This approach may provide additional blood pressure monitoring for the elderly persons susceptible to blood pressure variations during the time between two nursing visits. We conducted a retrospective pilot study on two residents of the TigerPlace aging in place facility with age over 70, that had blood pressure measured between 100 and 300 times during a period of two years. The pilot study suggested that abnormal pulse pressure can be reasonably well estimated (an area under ROC curve of about 0.75) using apartment bed and motion sensors.

• Journal of Ocean Engineering and Technology
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• v.31 no.1
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• pp.60-68
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• 2017

In this study, we analyzed the real time video image obtained from the video monitoring system to grasp the shoreline, beach width, and area change of Haeundae beach. The video monitoring techniques enabled continuous monitoring for a long period at a much lower cost than general survey methods. It was possible to grasp quantitative beach variation characteristics of Haeundae beach through image acquisition, rectification, and image processing of video images. According to the monitoring results, the erosion rate of Haeundae beach in spring and summer was -19.8% in 2014 and -6.7% in 2015. The erosion rate in 2016 was -6.4%, which showed that the erosion rate in spring and summer continued to decrease. In particular, the influence of the erosion at the time of typhoon CHABA was revealed to be smaller than in the past. It can be concluded that these variations were due to beach width expansion by beach nourishment and the installation of submerged breakwaters.

• KCID journal
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• v.17 no.2
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• pp.71-81
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• 2010

Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods applicable to nature-like streams. Stream restoration projects aim to maintain or increase ecosystem goods and services while protecting downstream and coastal ecosystems. Fields environmental monitoring such as flow discharge and precipitation were conducted along the Idong stream for amount of channel zone change in 2007. This study selected three monitoring positions to measure the water level and discharge of flowing water. A stage-discharge relation is obtained from direct discharge measurements for three stations by fitting an empirical relationship to the data set. Since discharge measures are made only for low flow conditions, a curve of discharge against stage can then be built by fitting these data with a power curve. And this study used data obtained from floodmark checkup as well as HEC-RAS model to analyze the hydrodynamic characteristics of monitoring sites. Reach-averaged hydraulic parameters for the supply reach were calculated from the small area's HEC-RAS model for Idong stream, and a HEC-RAS model used to analyze hydraulics for a period in 2007, after the stream was considered bank stabilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1169-1177
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• 2009

This paper presents an energy efficient MAC protocol for delay-sensitive data transmission over wireless sensor network. In general, energy consumption and delay depend on Channel Monitoring Interval and data sensing period at each sensor node. Based on this fact, we propose a new preamble structure to effectively advertise Channel Monitoring Interval and avoid the overhearing problem. In order to pursue an effective tradeoff between energy consumption and delay, we also develop a Channel Monitoring Interval determining algorithm that searches for a sub-optimal solution with a low computational complexity. Finally, experimental results are provided to compare the proposed MAC protocol with existing sensor MAC protocols.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.2
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• pp.53-63
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• 2016

Monitoring of cyanobacteria bloom in reservoir systems is important for water managers responsible of water supply system. Cyanobacteria affect the taste and smell of water and pose considerable filtration problems at water use places. Harmful cyanobacteria bloom in reservoir have significant economic impacts. We develop a new method for estimating the cyanobacteria bloom using Landsat TM and ETM+ data. Developed model was calibrated and cross-validated with existing in situ measurements from Daecheong Reservoir's Water Quality Monitoring Program and Algae Alarm System. Measurements data of three stations taken from 2004 to 2012 were matched with radiometrically converted reflectance data from the Landsat TM and ETM+ sensor. Stepwise multiple linear regression was used to select wavelengths in the Landsat TM and ETM+ bands 1, 2 and 4 that were most significant for predicting cyanobacteria cell number and bio-volume. Based on statistical analysis, the linear models were that included visible band ratios slightly outperformed single band models. The final monitoring models captured the extents of cyanobacteria blooms throughout the 2004-2012 study period. The results serve as an added broad area monitoring tool for water resource managers and present new insight into the initiation and propagation of cyanobacteria blooms in Daecheong reservoir.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.53-60
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• 2018

The ICT concept has been introduced to realize a highly productive smart factory and respond to the demand for small quantity and mass production between textile processes. ICT convergence monitoring system that can produce high productivity textile products by improving product development period, cost, quality and delivery time through ICT based production and optimization of manufacturing process is needed. In this paper, we propose and implement a system design that senses the amount of remaining sewing material using a non-contact sensor that can be mounted on a sewing machine and displays it on a display using IOT-based LATTE-PANDA board.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.8
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• pp.738-743
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• 2012

This paper describes analysis of long-term experiments on a monitoring system to assess the daily activities of the elderly who live alone. The developed system is composed of an in-house sensing system and a server system. The in-house sensing system installed in their own houses is a typical wireless sensor network system including three kinds of wireless sensors. The server system has a database server and an assessment server. We have installed the system into an elderly house, collected data during over two years continuously, then analyze the data. From the analysis, we could measure the energy consumption profile of three kinds of sensor nodes. The experiment shows all kinds of nodes can operate over one year with two AA-size alkaline batteries. Using a measure of reliability of the monitoring system called 'deadzone', the system has showed the failure operation for 842 hours (4.66 %) during over 18,000 hours total operation period.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.98-113
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• 2016

A reactor vessel level monitoring system measures the water level in a reactor during normal operation and abnormal conditions. A drop in the water level can expose nuclear fuel, which may lead to fuel meltdown and radiation spread in accident conditions. A level monitoring system mainly consists of a sensing line and pressure transmitter. Over a period of time boron sediments or other impurities can clog the line which may degrade the accuracy of the monitoring system. The aim of this study is to determine blockage in a sensing line using the energy of the composite signal. An equivalent Pi circuit model is used to simulate blockages in the sensing line and the system's response is examined under different blockage levels. Composite signals obtained from the model and plant's unblocked and blocked channels are decomposed into six levels of details and approximations using a wavelet filter bank. The percentage of energy is calculated at each level for approximations. It is observed that the percentage of energy reduces as the blockage level in the sensing line increases. The results of the model and operational data are well correlated. Thus, in our opinion variation in the energy levels of approximations can be used as an index to determine the presence and degree of blockage in a sensing line.