• Neonatal Medicine
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• v.28 no.1
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• pp.59-63
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• 2021

An important, albeit rare, cause of fetal bradycardia is long QT syndrome (LQTS). Congenital LQTS is an ion channelopathy caused by mutations in genes encoding cardiac ion channel proteins. Fetal onset of LQTS imposes high risk of life-threatening tachyarrhythmias and sudden cardiac death. Here, we report the case of a female newborn with fetal onset of bradycardia and a 2:1 atrioventricular (AV) block. After birth, a 12-lead electrocardiogram (ECG) revealed bradycardia with QT prolongation of a corrected QT (QTc) interval of 680 ms and pseudo 2:1 AV block. Genetic testing identified a heterozygous Gly402Ser (c.1204G>A) mutation in CACNA1C, confirming the diagnosis of LQTS type 8 (LQT8). The patient received propranolol at a daily dose of 2 mg/kg. Mexiletine was subsequently administered owing to the sustained prolongation of the QT interval and pseudo 2:1 AV block. One week after mexiletine inception, the ECG still showed QT interval prolongation (QTc, 632 ms), but no AV block was observed. There were no life-threatening tachyarrhythmias in a follow-up period of 13 months.

• Journal of radiological science and technology
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• v.21 no.2
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• pp.11-18
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• 1998

Single phase, narrow beam X-ray attenuation data were obtained using various construction materials concrete, white block, red block, 3 hole block, gypsum board, artificial marble, cement, plate glass, wood, and lead. Tube voltages of 60, 80, 100, 120 kVp were employed and the resulting curves were compared to transmission data found in this report. The shielding methodology and the derivation of equations used for determination of barrier requirements were presented in NCRP 49. We could calculate the X-ray exposed dose after attenuation and thickness of protection barrier in the clinic facilities accordingly. For the purpose of maximizing the benefit/cost ratio to diagnostic shielding, various construction materials must be installed carefully and attnuation rate considered thoroughly.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.428-439
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• 2020

The continuous development of information and communication technologies has resulted in an exponential increase in data. Consequently, technologies related to data analysis are growing in importance. The shipbuilding industry has high production uncertainty and variability, which has created an urgent need for data analysis techniques, such as machine learning. In particular, the industry cannot effectively respond to changes in the production-related standard time information systems, such as the basic cycle time and lead time. Improvement measures are necessary to enable the industry to respond swiftly to changes in the production environment. In this study, the lead times for fabrication, assembly of ship block, spool fabrication and painting were predicted using machine learning technology to propose a new management method for the process lead time using a master data system for the time element in the production data. Data preprocessing was performed in various ways using R and Python, which are open source programming languages, and process variables were selected considering their relationships with the lead time through correlation analysis and analysis of variables. Various machine learning, deep learning, and ensemble learning algorithms were applied to create the lead time prediction models. In addition, the applicability of the proposed machine learning methodology to standard work hour prediction was verified by evaluating the prediction models using the evaluation criteria, such as the Mean Absolute Percentage Error (MAPE) and Root Mean Squared Logarithmic Error (RMSLE).

• Journal of Chest Surgery
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• v.14 no.2
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• pp.168-174
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• 1981

Since cardiac pacemaker was first totally implanted by Chardack, Gage and Greatbatch [1966], the electrical circuity of the cardiac pacemaker has been improved, modified, and refined. The problem of transvenous electrodes, however, is still remained; this may be due to electrode displacement, exit and/or entrance block, lead fracture and insulation defects. In permanent cardiac pacing, Irreversible loss of function of the transvenous electrode catheter eventually requires insertion of new lead. Authors now report one case that disclosed easy displacement of electrode tip in early phase of implantation and then two years and five months later, malfunctioning electrode could not be withdrawn from the cardiovascular system because it has become firmly enclosed by fibrous tissue along its course from the vein tract to the right ventricle. Under such circumstances, the electrode catheter tip was left in tricuspid annulus after being sutured at its entrance and burying the loop of lead in generator pocket. New other one electrode was then reimplantation through left external jugular vein.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.966-970
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• 2011

The thermo-mechanical interaction between brake block and wheel tread during braking has been found to cause thermal crack on the wheel tread. Due to thermal expansion of the rim material, the thermal cracks will protrude from the wheel tread and be more exposed to wear during the wheel/block contact than the rest of the tread surface. The wheel rim is in residual compression stress when is new. After service running, the region in the tread has reversed to tension. This condition can lead to the formation and growth of thermal cracks in the rim which can ultimately lead to premature failure of wheel. In the present paper, the thermal cracks of railway wheel, one of severe damages on the wheel tread, were evaluated to understand the safety of railway wheel in running condition. The residual stresses for damaged wheel which are applied to tread brake are investigated. Mainly X-ray diffusion method is used. Under the condition of concurrent loading of continuous rolling contact with rails and cyclic frictional heat from brake blocks, the reduction of residual stress is found to correlate well with the thermal crack initiation.

• KSCI Review
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• v.1 no.2
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• pp.95-107
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• 1995

The concurrency control can be critical to the performance of transaction processing systems. Conventional locking takes the blocking phenomenon, where waiting transactions continue to hold locks and block other transactions from progressing. The proposed scheme reduces the blocking probability by deferring the blocking behavior of transactions to the later stages of their execution. The transaction execution can be divided into a nonblocking phase where transactions wait for locks but do not block other transactions and a blocking phase as in conventional locking. However data accessed during the nonblocking phase can lead to transaction abort. By properly balancing the blocking and abort effects, the proposed scheme can lead to better performance than either the conventional locking or the optimistic concurrency control(OCC) scheme at all data and resource contention levels.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.161-166
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• 2015

The inappropriate hydraulic design criteria on the new revetment technique for the ecological river restoration project happens to lead to economic loss during the flood season. In this study, the hydraulic stability of the developed non-toxic revetment was evaluated at a maximum discharge of $3.0m^3/s$ and a maximum velocity of 3.0 m/s in a real scale experimental channel. The vertical movement of the non-toxic revetment block was in the range of ${\pm}3mm$ mm in the experimental conditions. The results show that the non-toxic revetment block was sufficiently hydraulically secured.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.18-30
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• 2022

Predicting remaining useful life (RUL) becomes significant to implement prognostics and health management of industrial systems. The relevant studies have contributed to creating RUL prediction models and validating their acceptable performance; however, they are confined to drive reasonable preventive maintenance strategies derived from and connected with such predictive models. This paper proposes a data-driven preventive maintenance method that predicts RUL of industrial systems and determines the optimal replacement time intervals to lead to cost minimization in preventive maintenance. The proposed method comprises: (1) generating RUL prediction models through learning historical process data by using machine learning techniques including random forest and extreme gradient boosting, and (2) applying the system failure time derived from the RUL prediction models to the Weibull distribution-based minimum-repair block replacement model for finding the cost-optimal block replacement time. The paper includes a case study to demonstrate the feasibility of the proposed method using an open dataset, wherein sensor data are generated and recorded from turbofan engine systems.

• Journal of Yeungnam Medical Science
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• v.32 no.2
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• pp.152-154
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• 2015

Arrhythmias are complications of tunneled cuffed hemodialysis catheter insertion. Most complications associated with arrhythmias occur during guide-wire access, where the guide wire can cause traumatic damage to the conduction system of the heart. Conducting system injury in tunneled cuffed hemodialysis catheter insertion often involves the right bundle, causing right bundle branch block (RBBB). Transient RBBB with sinus rhythm is not usually accompanied by abnormal vital signs. However if patients already have left bundle branch block (LBBB), new onset RBBB can cause complete atrioventricular block (AVB), which can lead to fatal complications requiring invasive treatment. We report on a patient with LBBB who developed complete AVB during hemodialysis catheter insertion.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.265-270
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• 1976

Implantation of a permanent pacemaker is a widely accepted procedure for the patient with complete heart block.As a result of these device, the prognosis for patients with Adams-Stokes syndrome caused by complete A-V block and other cardiac arrhythmia have become much more optimistic. Permanent pacemaker implantation by means of a transvenous approach has made the operative risk much less and the procedure simpler. However, a number of complications have been reported in the literature regarding transvenous endocardial pacemaker implantation during the last a decade. The patient presented in this paper is a 26-year old girl who was implanted with a permanent pacemaker at 14 years of age because of a congenital A-V block. Following first exchange of pulse generator, the electrode (lead) was fractured, so that by the pulse generator, a change to the transvenous technique of implantation was made, After this, there were episodes of recurrent wound infection on three occasions, even though the site of pulse generator implantation was exchanged to the contralateral side of chest wall, massive doses of antibiotics were administered and sensitivity tests for coagulase positive staphylococcal infection were performed. Though there was no definite evidence of blood stream infection by blood culture, we decided not to use the transvenous technique and not to implant the pulse generator in the chest wall because the venous system and the entire anterior chest wall appeared to be diseased or contaminated by virulent pyogenic organisms. Finally this intractable systemic and local wound infection was successfully controlled by myocardial lead implantation via a subxiphoid approach and implantation of the pulse generator far down in the abdominal wall. The causes and routes of recurrent wound infection and possible blood born infection in this particular patient are still obscure. We strongly believe that myocardial pacemaker implantation is much safer than transvenous endocardial pacemaker implantation & myocardial pacemaker implantation is a definite method for controlling such an intractable wound infection. following transvenous pacemaker implantation.