• Structural Monitoring and Maintenance
• /
• v.1 no.1
• /
• pp.89-110
• /
• 2014

Structural Health Monitoring (SHM) is an effective alternative to conventional inspections which are time-consuming and subjective. SHM can detect damage early and reduce maintenance cost and thereby help reduce the likelihood of catastrophic structural events to infrastructure such as bridges. After reviewing the Damage Index Method (DIM), an Iterative Damage Index Method (IDIM) is proposed to improve the accuracy of damage detection. These two damage detection techniques are compared based on damage on two structures, a simply supported beam and a pedestrian bridge. Compared to the traditional damage detection algorithm, the proposed IDIM is shown to be less arbitrary and more accurate.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.101-106
• /
• 2007

A time-lapse microgravity survey on a newly widen road at Muan, where limestone cavities are developed, for monitoring the change of the subsurface density distribution before and after grouting. Microgravity monitoring is identified as a quick, easy and cost effective. But, it requires strict data acquisition and quality control due to the differences of conditions at measurements. The survey was carried out two times, that is, October 2005 and September 2006. The data were adjusted for reducing the effects due to the different condition of each survey. The processed data acquired in 2005 and 2006 were inverted into the subsurface density distributions. They show the change and development of density structure during the lapsed time, which implies the effects of grouting.

• Journal of the Optical Society of Korea
• /
• v.12 no.3
• /
• pp.166-169
• /
• 2008

The submersion monitoring system based on a reflective side-polished optical fiber submersion sensor with an optical fiber mirror was shown to be an effective alarm system with remote monitoringwhen the drainage capacity of a common utility duct is exceeded due to heavy rainfall. The proposed sensor was connected to an existing installed optical fiber network at a height of 250mm in a common utility duct, and then tested under sample materials(distilled water, river water, sea water, foul water, muddy water, petroleum, edible oil) at a distance of 1km from the sensor for remote sensing. In experiments, the proposed real-time sensor system reduced maintenance cost and improved monitoring efficiency by using a reflection-type side-polished optical fiber submersion sensor efficient for remote monitoring of a common utility duct.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.6
• /
• pp.115-121
• /
• 2011

Intelligent distribution equipment is inevitable to realize self-healing which is one of smart grid functions in distribution network. Therefore, most of distribution equipment have been developed with self diagnostic sensors. However, it is not effective to construct on-line monitoring system for underground distribution cable because of high cost and low sensitivity. Recently, optical fiber composite cable is being considered for communication and power delivery in order to cope with increasing communication in distribution network. This paper presents the design and performance assessment results of underground cable on-line monitoring system using DTS(Distributed Temperature Sensing) and optical fiber composite underground cable.

• International conference on construction engineering and project management
• /
• 2007.03a
• /
• pp.50-60
• /
• 2007

The endeavor of this paper focuses on designing a monitoring system to provide a cost-effective solution on quality assurance for construction projects. The construction site monitoring system integrates a long-range wireless network, network cameras, and a web-based collaborative platform. The users of the system could obtain the most updated status of construction sites, such as behaviors of workers, project progress, and site events anywhere with Internet connectivity. It was carefully configured in order to maintain the reliability under the reactive conditions of the construction sites. This paper reports the architecture of the monitoring system and reviews the related technologies. The system has been implemented and tested on a construction site and promising results were obtained.

• Tribology and Lubricants
• /
• v.26 no.1
• /
• pp.73-77
• /
• 2010

One of the important trends for condition monitoring in the 21st century is the development of smart sensors that will permit the cost-effective continuous monitoring of key machine equipments. In this study, an integrated in-line oil monitoring sensor assigned for continuous in situ monitoring multiple parameters of oil performance is presented. The sensor estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical density of oil in three optical wave-bands ('Red', 'Green' and 'Blue') and water content is evaluated as relative saturation of oil by water. In order to evaluate the sensor's effectiveness, the sensor was applied to several used oil samples in steel making industry and the results were compared with those measured by standard test methods.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.169-173
• /
• 1998

The practice of the construction and management of the underground petroleum storage facilities in Korea was investigated extensively, and the problems were identified. The advanced technologies in the U.S.A was comparatively studied. Considering the effectiveness of leak prevention and technology applicability, the following measures were suggested. To prevent corrosion of the tank, a clad tank, an interior-lining tank, or a double-wall tank was appropriate and appeared to be most cost effective. For piping, non-metalic material was suggested. To prevent spill, a catchment basin can be effective. For monitoring of leak, construction of more than one of one or combination of an automatic leak-detection device, a vapor-detection system, a ground water-monitoring system, and a double-wall detection system was recommended.

• Smart Structures and Systems
• /
• v.17 no.1
• /
• pp.135-147
• /
• 2016

This paper describes a smart structural system, which uses smart materials for real-time monitoring and active control of bolted-joints in steel structures. The goal of this research is to reduce the possibility of failure and the cost of maintenance of steel structures such as bridges, electricity pylons, steel lattice towers and so on. The concept of the smart structural system combines impedance based health monitoring techniques with a shape memory alloy (SMA) washer to restore the tension of the loosened bolt. The impedance-based structural health monitoring (SHM) techniques were used to detect loosened bolts in bolted-joints. By comparing electrical impedance signatures measured from a potentially damage structure with baseline data obtained from the pristine structure, the bolt loosening damage could be detected. An outlier analysis, using generalized extreme value (GEV) distribution, providing optimal decision boundaries, has been carried out for more systematic damage detection. Once the loosening damage was detected in the bolted joint, the external heater, which was bonded to the SMA washer, actuated the washer. Then, the heated SMA washer expanded axially and adjusted the bolt tension to restore the lost torque. Additionally, temperature variation due to the heater was compensated by applying the effective frequency shift (EFS) algorithm to improve the performance of the diagnostic results. An experimental study was conducted by integrating the piezoelectric material based structural health monitoring and the SMA-based active control function on a bolted joint, after which the performance of the smart 'self-monitoring and self-healing bolted joint system' was demonstrated.

• Korean Journal of Clinical Pharmacy
• /
• v.11 no.1
• /
• pp.1-6
• /
• 2001

This research is conducted to evaluate the clinical and economic benefits from therapeutic drug monitoring(TDM) service on vancomycin in a tertiary general hospital. Total 99 pairs of steady state peak and trough concentrations of vancomycin were obtained from 73 patients. To see the clinical benefits, the appropriateness of vancomycin dosing before TDM was evaluated. In 72 pairs of vancomycin blood concentrations obtained prior to TDM consultation, $47.2\%$ of the cases had reached within therapeutic range. Serum vancomycin levels in patients with $40{\leq}CLcr<60$ (ml/min) were higher and than the levels in patients with 40>CLcr and $60{\leq}CLcr$ (ml/min). Dose reduction rate in patients with creatinine clearance $40{\leq}CLcr<60$ (ml/min) were also significantly higher than those of compared groups ($61.5\%$, p=0.0138). Serum vancomycin concentrations were re-obtained from 21 patients who received modified dose through TDM service. Ninety percent (19/21cases) of them were within the target therapeutic range. For the evaluation of economic benefits from TDM consultation, estimated cost savings were calculated in those patients. The total drug saving were 586 vials in 21 patients. The calculated mean cost saving from the drugs was 314,570 won (range: $11,273\sim473,466)$ per patient. The study revealed that TDM service for vancomycin is necessary because empirical dosing is not effective for obtaining therapeutic drug level, especially patients with mild renal insufficiencies. The cost saving from TDM is also beneficial for the patients.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.3
• /
• pp.1101-1107
• /
• 2010

DVR is widely used in the security monitoring system because it has excellent performance compared with VCR. In this paper, the new DVR interfaces and repeaters enhancing the performance of the existing DVR have been designed and implemented, which enables a large-scaled security monitoring system to be built economically. A repeater in this paper connects 8 monitoring terminals to 2 channels of DVR and a DVR interface manages 16 repeaters to be able to accommodate 128 monitoring terminals. Eventually, the implemented system has a quadruple scalability compared to the existing systems and can reduce the installation cost substantially by using cost-effective UTP cables instead of coaxial cables. And the system could be effectively used in various environments and conditions because various functions such as video transmission, audio communication, emergency call, and RFID card are integrated into the system.