• Title/Summary/Keyword: Long-term monitoring

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Test-bed Development for Long-term Monitoring of Small Bridge Asset Management (소규모 교량 자산관리를 위한 계측 테스트베드 구축)

  • Park, Jae-Woo;Chae, Myung-Jin;Lee, Giu;Cho, Moon-Young
    • Korean Journal of Construction Engineering and Management
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    • v.13 no.6
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    • pp.13-23
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    • 2012
  • While Category 1 and Category 2 bridges are intensively inspected and carefully managed, many small bridges that are not in the Category 1 and 2 are often forgotten until they decay in serious condition. Since many of these small bridges located in the populated city, failure of them would cause huge negative impact on the community. This paper focuses on the small size concrete bridges for timely repair and rehabilitation work for the effective operation and management. Test bed is developed to define the key parameters to forecast the long term performance of the bridges, mostly concrete box bridges. Key parameters suggested in this paper are cumulative fatigue due to repetitive heavy traffic loads and the acid attacks for concrete material deterioration. The cumulative fatigue is measured by the use of the mileage concept. For the long term data collection and inspection, stable and easy to use data collection system is installed as a test bed. The contribution of this research work is on the development of the test bed to define the key parameters of bridge deterioration.

Study on the performance analysis of long-term field test for protected horticulture heating system using solar thermal energy (태양열 시설원예 난방시스템 장기실증 성능분석 연구)

  • Lee Sang-Nam;Kang Yong-Heack;Yu Chang-Kyun;Kim Jin-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.403-407
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    • 2005
  • Objective of the research is to demonstrate solar thermal space and ground heating system which is integrated to a greenhouse culture facility for reducing heating cost, increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Field test for the demonstration was carried out in horticulture complex in Jeju Island. Medium scale solar hot water system was installed in a ground heating culture facility. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Short term day test on element performance and Long term test of the whole system were carried out. Optimum operating condition and its characteristics were closely investigated by changing the control condition based on the temperature difference which is the most important operating parameter. For establishing more reliable and optimal design data regarding system scale and operation condition, continuous operation and monitoring on the system need to be further carried out. However, it is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

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Study on the performance analysis of long-term field test for protected horticulture heating system using solar thermal energy (태양열 시설원예 난방시스템 장기실증 성능분석 연구)

  • Lee Sang-Nam;Kang Yong-Heack;Yu Chang-Kyun;Kim Jin-Soo
    • New & Renewable Energy
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    • v.1 no.2 s.2
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    • pp.53-59
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    • 2005
  • Objective of the research is to demonstrate solar thermal space and ground heating system which is integrated to a green-house culture facility for reducing healing cost, Increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Field test for the demonstration was carried out in horticulture complex In Jeju Island. Medium scale solar hot water system was installed in a ground heating culture facility. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Short term day test on element performance and Long term test of the whole system were carried out. Optimum operating condition and its characteristics were closely Investigated by changing the control condition based on the temperature difference which Is the most important operating parameter For establishing more reliable and optimal design data regarding system scale and operation condition, continuous operation and monitoring on the system need to be further carried out. However, It is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

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Automated epileptic seizure waveform detection method based on the feature of the mean slope of wavelet coefficient counts using a hidden Markov model and EEG signals

  • Lee, Miran;Ryu, Jaehwan;Kim, Deok-Hwan
    • ETRI Journal
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    • v.42 no.2
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    • pp.217-229
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    • 2020
  • Long-term electroencephalography (EEG) monitoring is time-consuming, and requires experts to interpret EEG signals to detect seizures in patients. In this paper, we propose a novel automated method called adaptive slope of wavelet coefficient counts over various thresholds (ASCOT) to classify patient episodes as seizure waveforms. ASCOT involves extracting the feature matrix by calculating the mean slope of wavelet coefficient counts over various thresholds in each frequency subband. We validated our method using our own database and a public database to avoid overtuning. The experimental results show that the proposed method achieved a reliable and promising accuracy in both our own database (98.93%) and the public database (99.78%). Finally, we evaluated the performance of the method considering various window sizes. In conclusion, the proposed method achieved a reliable seizure detection performance with a short-term window size. Therefore, our method can be utilized to interpret long-term EEG results and detect momentary seizure waveforms in diagnostic systems.

Evaluation Method for Measurement System and Process Capability Using Gage R&R and Performance Indices (게이지 R&R과 성능지수를 이용한 측정시스템과 공정능력 평가 방법)

  • Ju, Youngdon;Lee, Dongju
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.42 no.2
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    • pp.78-85
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    • 2019
  • High variance observed in the measurement system can cause high process variation that can affect process capability badly. Therefore, measurement system analysis is closely related to process capability analysis. Generally, the evaluation for measurement system and process variance is performed separately in the industry. That is, the measurement system analysis is implemented before process monitoring, process capability and process performance analysis even though these analyses are closely related. This paper presents the effective concurrent evaluation procedure for measurement system analysis and process capability analysis using the table that contains Process Performance (Pp), Gage Repeatability & Reproducibility (%R&R) and Number of Distinct Categories (NDC). Furthermore, the long-term process capability index (Pp), which takes into account both gage variance and process variance, is used instead of the short-term process capability (Cp) considering only process variance. The long-term capability index can reflect well the relationship between the measurement system and process capability. The quality measurement and improvement guidelines by region scale are also described in detail. In conclusion, this research proposes the procedure that can execute the measurement system analysis and process capability analysis at the same time. The proposed procedure can contribute to reduction of the measurement staff's effort and to improvement of accurate evaluation.

Channel change of the Naesung Stream during 2012~201 (2012~2016년 기간 내성천의 하도 변화)

  • Lee, Chanjoo;Kim, Donggu;Kim, Ji-Sung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.333-333
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    • 2017
  • Recently, long-lasting landscape of the Naesung Stream has been changed due to encroachment of vegetation. To analyze patterns and causes of these changes, Korea Institute of Civil Engineering and Building Technology (KICT) has been carried out long-term monitoring research for the 56.8 km long study reach of the Naeseong Stream. Using the consecutive airborne LiDAR survey data obtained from 2012~2016, changes of channel bed forms such as bars could be detected. For the last four years of monitoring, mid-channel bars has been formed along the straight reaches and the existing bars showed vertical accretion caused by deposition on the vegetated surfaces.

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Measured structural response of a long irregular pit constructed using a top-down method

  • Yang, Sun;Yufei, Che;Zhenxue, Gu;Ruicai, Wang;Yawen, Fan
    • Geomechanics and Engineering
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    • v.31 no.5
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    • pp.489-503
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    • 2022
  • A 1257-m-long irregular deep foundation pit located in the central of Nanjing, China was constructed using the combined full-width and half-width top-down method. Based on the long-term field monitoring data, this study analyzed the evolution characteristics of the vertical movement of the columns, internal force of the struts, and axial force of the structural beam and slab. The relevance of the three mentioned above and their relationship with the excavation process, structural system, and geological conditions were also investigated. The results showed that the column uplift was within the range of 0.08% to 0.22% of the excavation depth, and the embedded depth ratio of the diaphragm wall and the bottom heave affected significantly on the column uplift. The differential settlement between the column and diaphragm wall remained unchanged after the base slab was cast. The final settlement of the diaphragm wall was twice the column uplift. The internal force of the struts did not varied monotonically but was related to numerous factors such as the excavation depth, number of struts, and environmental conditions. Additionally, the dynamic force and deformation of the columns, beams, and slabs were analyzed to investigate the inherent relationship and variation patterns of the responses of different parts of the structure.

Evaluation of Long-term Data Obtained from Seawater Intrusion Monitoring Network using Variation Type Analysis (변동유형 분석법을 이용한 해수침투 관측망 자료 평가)

  • Song, Sung-Ho;Lee, Jin-Yong;Yi, Myeong-Jae
    • Journal of the Korean earth science society
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    • v.28 no.4
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    • pp.478-490
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    • 2007
  • With groundwater data of seawater intrusion monitoring network in coastal areas of Korea's main land, we analyzed types of seawater intrusion through the coastal aquifer. The data including groundwater level, temperature and electrical conductivity obtained from 45 monitoring wells at 25 watershed regions were evaluated. Based on statistical analysis, correlation analysis and variation type analysis, groundwater levels were mainly affected by rainfall and artificial pumping. About 78% of the monitoring wells showed average temperature higher than $15^{\circ}C$ and about 58% of them showed minimum variations less than $0.2^{\circ}C$. Electrical conductivities showed a large magnitude of variation and irregular characteristics compared with groundwater levels and temperatures. Average electrical conductivities lower than $2,000\;{\mu}S/cm$ were observed at 28 monitoring wells while those of higher than $10,000\;{\mu}S/cm$ were done at 9 monitoring wells. From the cross-correlation analysis, groundwater levels were mostly affected by precipitation while temperature and electrical conductivity showed very low correlation. Meanwhile tidal variations strongly affected the groundwater levels comparing to precipitation. We classified the long-term monitoring data according to variation types such as constant process, linear trend, cyclic variation, impulse, step function and ramp. Impulse type was dominant for variations of groundwater level, which was largely affected by rainfall or artificial pumping, the constant process was dominant for temperature. Compared with groundwater level and temperature, electrical conductivities showed various types like linear trend, step function and ramp. According to the discrepancy of variation characteristics for monitoring data at each well in the same region, periodical analysis of monitoring data is essentially required.

A Leading-Edge Operation Program of the East Sea Branch, KORDI

  • Jeon, Dong-Chull
    • Ocean and Polar Research
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    • v.28 no.2
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    • pp.209-214
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    • 2006
  • The East Sea Branch (ESB) of KORDI will be launched in 2008. She will take a role of monitoring the sea surface topography and temperature by satellites, short- and long-term sea levels by tide gauges, coastal currents and open-sea circulation by setting up coastal radars and mooring current-meters and acoustic equipments, as well as monitoring nearshore processes, coastal erosion and water pollution. A basic program of coastal zone management will help ocean-policy makers to set up right decisions based upon scientific background of the regional data in the East Sea. Networking among the neighboring countries around the sea will supply more useful information not only for experts but also for ordinary vacationers or fishermen. In order for this program to be successfully settled down during the next decade, it is necessary for a leader to have the right vision to attract more experts from global brain pools and to manage the ESB as a leading-edge observatory in the world. Details about this leading-edge operational program are introduced in the text.