• Journal of Gastric Cancer
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• v.24 no.2
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• pp.137-144
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• 2024

Purpose: Laparoscopic proximal gastrectomy (LPG) is a viable choice for treating proximal gastric lesions. However, the occurrence of severe reflux has limited its widespread adoption. To address this issue, the double flap technique (DFT), which incorporates artificial lower esophageal sphincteroplasty, has been developed to prevent reflux problems after proximal gastrectomy. In this study, we aimed to investigate the usefulness of this technique using high-resolution manometry (HRM), impedance pH monitoring, and esophagogastroduodenoscopy (EGD). Materials and Methods: The findings of pre- and postoperative 6-month HRM, pH monitoring, and EGD were compared for 9 patients who underwent LPG with DFT for various proximal gastric lesions at Incheon St. Mary's Hospital from January 2021 to December. Results: A total of 9 patients underwent proximal gastrectomy. Approximately half of the patients had Hill's grade under II preoperatively, whereas all patients had Hill's grades I and II in EGD findings. In the HRM test, there was no significant difference between distal contractile integral (1,412.46±1,168.51 vs. 852.66±495.62 mmHg·cm·s, P=0.087) and integrated relaxation pressure (12.54±8.97 vs. 8.33±11.30 mmHg, P=0.27). The average lower esophageal sphincter (LES) pressure was 29.19±14.51 mmHg preoperatively, which did not differ from 19.97±18.03 mmHg after the surgery (P=0.17). DeMeester score (7.02±6.36 vs. 21.92±36.17, P=0.21) and total acid exposure time (1.49±1.48 vs. 5.61±10.17, P=0.24) were slightly higher, but the differences were not statistically significant. Conclusions: There is no significant functional difference in HRM and impedance pH monitoring tests after DFT. DFT appears to be useful in preserving LES function following proximal gastrectomy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.387-392
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• 2019

A technique was researched to detect bolt looseness using a transfer impedance technique (the dual piezoelectric material technique) for monitoring the structural health of a bolt joint. In order to use the single piezoelectric material technique, an expensive impedance analyzer should be used. However, in the transfer impedance technique, low-cost fault detection can be performed using a general function generator and a digital multimeter. A steel plate frame test specimen composed of bolt joints was fabricated, and the tightening torques of the bolts were loosened step by step. By using the transfer impedance method, the damage index was obtained. It was found that the presence of faults could be reasonably estimated using the damage index, which increased with the degree of bolt looseness. An experiment was performed on the same specimen using the single piezoelectric material technique, and the results showed a similar tendency. It could be possible to estimate the damage of a bolt joint at low cost by eliminating the expensive impedance analyzer. This method could be used effectively for structural health monitoring after carrying out a study to estimate the fault location and severity.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.131-137
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• 2004

GPS/Meteorology technique for PWV monitoring is currently actively being researched an advanced nation. We deal with the monitoring of GPS derived PWV during the passage of Typhoon MAEMI. Typhoon MAEMI which caused a series damage was passed over in Korea peninsula from September 12 to September 13, 2003. We obtained GPS-PWV at 17th GPS permanent stations. We retrieve GPS data hourly and use Gipsy-Oasis II software. The GPS-PWV time series results demonstrate that PWV is, in general, high before and during the occurrence of the typhoon, and low after the typhoon.

• Smart Structures and Systems
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• v.20 no.3
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• pp.343-350
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• 2017

An experimental study is presented of the application of fiber Bragg grating (FBG) interrogation method based on optical time-domain reflectometery (OTDR) to monitoring strain in bent reinforced concrete beams. The results obtained with the OTDR-based method are shown to agree well with the direct spectral measurements. Strain sensitivity, resolution and measurement range amounted to $0.0028dB/{\mu}strain$; $30{\mu}strain$; $4000{\mu}strain$, correspondingly. Significant differences are observed in surface and inner deformations of the test beams which can be attributed to different mechanical properties of concrete and steel reinforcement. The prospects of using OTDR-based FBG interrogation technique in real-life applications are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.156-162
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• 2006

Pipe thinning is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. In this paper, we proposed the method for monitoring pipe thinning. Our basic idea come from that a group velocity of impact wave is different as wall thickness. If the group velocity is measured, wall thickness can be estimated. To obtain the group velocity, time-frequency analysis is used. This is because an arrival time difference can be measured easily in time-frequency domain rather than time domain. To test the performance of this technique, experiments have been performed for a plate and U type pipe. Results show that the proposed technique is quite powerful in the monitoring pipe thinning.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1224-1230
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• 2006

Pipe thinning is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. In this paper, we proposed the method for monitoring pipe thinning. Our basic idea come from that a group velocity of impact wave is different as wall thickness. If the group velocity is measured, wall thickness can be estimated. To obtain the group velocity, time -frequency analysis is used. This is because an arrival time difference can be measured easily in time-frequency domain rather than time domain. To test the performance of this technique, experiments have been performed for a plate and U type pipe. Results show that the proposed technique is quite powerful in the monitoring pipe thinning.

• Tribology and Lubricants
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• v.3 no.1
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• pp.52-60
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• 1987

Many kinds of condition monitoring technique as the preventive maintenance technique have been studied, so this study has investigated the possibility of chbcking the trend in the fault diagnosis of ball bearing, one of the important elements of rotating machine, by applying the cepstral analysis method. And computer simulation is conducted in order to identify obviously the physical meaning of cepstral analysis. It is identified that cepstral analysis is effective method to distinguish between the basic and reflected wave by computer simulation, and we know that it is possible to apply the cepstral analysis to the arbitrary elements of rotating machine which are different in fundamental frequency. It is verified that cepstral analysis method is more effective than the other conventional method in bearing fault diganosis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.117-125
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• 2003

Since the recorded information used for operation of a catchment modelling system contain errors that influence the calibration of catchment modelling system control parameter values, the accurate estimation of these parameters is difficult. Despite these influences, existing traditional calibration approaches focus only on achieving the best "curve fitting" between simulated and recorded data, and not on generic evaluation of control parameter values. This paper introduces an Early Stopping Technique which is aimed at avoiding the procedure of curve-fitting through monitoring improvements in the objective function used for assessing the optimal parameter set. Application of this approach to the calibration of SWMM (Storm Water Management Model) on the Centennial Park catchment in Sydney, Australia is outlined. outlined.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.544-546
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• 2000

This paper presents a monitoring technique of pole transformers using AC bridge circuit. And to detect the capacitance in oil more effectively, this paper used AC bridge circuit. The sensor in oil which could be placed inside of the distribution transformer can measures the changes of capacitance in oil. And with the sensing of the upper part's capacitance, it is possible to determine the changes of the oil height. Establishment of the proposed system helps to build the confidence in monitoring of the pole transformers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.135-142
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• 2004

Two-step identification approach for effective bridge health monitoring is proposed to alleviate the issues associated with many unknown parameters faced in the real structures and to improve the accuracy in the estimate results. It is suitable for on-line monitoring scheme, since the damage assessment is not always needed to be carried out whereas the alarming for damages is to be continuously monitored. In the first step for screening potential damaged members, damage indicator method based on modal strain energy, probabilistic neural networks and the conventional neural networks using grouping technique are used and then the conventional neural network technique is utilized for damage assessment on the screened members in the second step. The proposed methods are verified through a field test on the northern-most span of old Hannam Grand Bridge.