• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.103-112
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• 2009

In a nuclear power plant (NPP), periodic sensor calibrations are required to assure sensors are operating correctly. However, only a few faulty sensors are found to be calibrated. For the safe operation of an NPP and the reduction of unnecessary calibration, on-line calibration monitoring is needed. In this paper, principal component-based Auto-Associative support vector regression (PCSVR) was proposed for the sensor signal validation of the NPP. It utilizes the attractive merits of principal component analysis (PCA) for extracting predominant feature vectors and AASVR because it easily represents complicated processes that are difficult to model with analytical and mechanistic models. With the use of real plant startup data from the Kori Nuclear Power Plant Unit 3, SVR hyperparameters were optimized by the response surface methodology (RSM). Moreover the statistical techniques are integrated with PCSVR for the failure detection. The residuals between the estimated signals and the measured signals are tested by the Shewhart Control Chart, Exponentially Weighted Moving Average (EWMA), Cumulative Sum (CUSUM) and generalized likelihood ratio test (GLRT) to detect whether the sensors are failed or not. This study shows the GLRT can be a candidate for the detection of sensor drift.

• Journal of Microbiology
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• v.42 no.4
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• pp.299-304
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• 2004

To investigate the presence of infectious agents in human atherosclerotic arterial tissues. Atherosclerotic plaques were removed from 128 patients undergoing carotid endarterectomy or other bypass proce­dures for occlusive disease, and from twenty normal arterial wall samples, obtained from transplant donors with no history of diabetes, hypertension, smoking, or hyperlipidemia. Using the polymerase chain reaction (PCR) or reverse transcription-PCR, these samples were analyzed for the presence of Chlamydia pneumoniae, cytomegalovirus, enterovirus, adenovirus, herpes simplex viruses types 1 and 2, and Epstein-Barr virus. The amplicons were then sequenced, and phylogenetic analyses were per­formed. Enteroviral RNA was found in 22 of 128 atherosclerotic vascular lesions $(17.2\%),$ and C. pneu­moniae and cytomegalovirus were each found in 2 samples $(1.6\%).$ In contrast, adenovirus, herpes simplex viruses, and Epstein-Barr virus were not identified in any of the atherosclerotic samples. Enterovirus was detected in 6/24 $(25.0\%)$ aortas, 7/33 $(21.2\%)$ carotid arteries, 6/40 $(15.0\%)$ femoral arteries, and 3/31 $(9.7\%)$ radial arteries of patients with chronic renal failure. There were no infectious agents detected in any of the control specimens. Using phylogenetic analysis, the enterovirus isolates were clustered into 3 groups, arranged as echovirus 9 and coxsackieviruses Bl and B3. Enteroviral RNA was detected in $17.2\%$ of atherosclerotic plaques, but was not observed in any of the control spec­imens. This suggests a connection between enteroviral infection and atherosclerosis. These findings dif­fer from those of other studies, which found more frequent incidence of C. pneumoniae and cytomegalovirus infection in atherosclerotic plaques.

• Smart Structures and Systems
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• v.12 no.1
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• pp.55-71
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• 2013

Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for sensing and damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory/field tests and possess significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and SHM applications. These films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. This study started with spin coating dispersed ZnO- and PVDF-TrFE-based solutions to fabricate the piezoelectric nanocomposites. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5 % increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled (at 50 $MV-m^{-1}$) to permanently align their electrical domains and to enhance their bulk film piezoelectricity. Then, a series of hammer impact tests were conducted, and the voltage generated by poled ZnO-based thin films was compared to commercially poled PVDF copolymer thin films. The hammer impact tests showed comparable results between the prototype and commercial samples, and increasing ZnO content provided enhanced piezoelectric performance. Lastly, the films were further validated for sensing using different energy levels of hammer impact, different distances between the impact locations and the film electrodes, and cantilever free vibration testing for dynamic strain sensing.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3843-3846
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• 2013

Objective: The purpose of this study was to assess prognosis after resection of giant tumors (including lobectomy or pneumonectomy) in the mediastinum. Materials and Methods: Patients with resection of a giant tumor in the mediastinum of the thoracic cavity received ICU treatment including dynamic monitoring of vital signs, arterial blood pressure and CVP detection, determination of hemorrhage, pulmonary function and blood gas assay, treatment of relevant complications, examination and treatment with fiber optic bronchoscopy, transfusion and hemostasis as well as postoperative removal of ventilators by invasive and non-invasive sequential mechanical ventilation technologies. Results: Six patients were rehabilitated successfully after ICU treatment with controlled postoperative errhysis and pulmonary infection by examination and treatment with fiber optic bronchoscopy without second application of ventilators and tubes after sequential mechanical ventilation technology. One patient died from multiple organ failure under ICU treatment due to postoperative active hemorrhage after second operative hemostasis. Conclusions: During peri-operative period of resection of giant tumor (including lobectomy or pneumonectomy) in mediastinum ofthe thoracic cavity, the ICU plays an important role in dynamic monitoring of vital signs, treatment of postoperative stress state, postoperative hemostasis and successful removal of ventilators after sequential mechanical ventilation.

• Journal of Korean Academy of Nursing
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• v.50 no.3
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• pp.369-384
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• 2020

Purpose: The purpose of this study was to analyze anxiety and depression among infertile women at different time points during the first In Vitro Fertilization (IVF) or Intracytoplasmic Sperm Injection (ICSI) treatment through a systematic review and meta-analysis. Methods: Seven out of 3,011 studies were included for meta-analysis. To estimate the effect size, a meta-analysis of the studies was performed using the RevMan 5.3 program. We compared the measurement outcomes at three time points: before the start of treatment (T0), cancellation of treatment after pregnancy detection (T2), one to six months after treatment (T3). The effect size used was the standardized mean difference (SMD). Results: In comparing the different time points of the pregnant women from their cycle, significantly lower levels of depression were found at T2 than at T0. In non-pregnant women, anxiety at T2 and depression at T2 and T3 were significantly higher than those at T0. At T2 and T3, the non-pregnant women reported higher levels of anxiety and depression compared with the pregnant women. Conclusion: Anxiety and depression in infertile women undergoing the first IVF or ICSI are associated with the time points and pregnancy status after treatment. These findings suggest that attention should be paid to helping infertile women prepare for and cope with treatment and treatment failure.

• Resources Recycling
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• v.25 no.4
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• pp.11-22
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• 2016

In global automobile industry, the remanufacturing for used products has the merit to be reduced nearly 80 percent of energy consumption and resources of new product. The objective of this paper is the analysis of detailed remanufacturing processes about research object and failure modes of each process of throttle body which is one of automobile parts, to draw a FMEA and determine the degree of seriousness (S), detection (D) and occurrence (O) of many failures. And we compared the current RPN method of being used to calculate values of RPN with three suggested methods. : Summation method, Square root method, Volume method.

• Composites Research
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• v.30 no.2
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• pp.126-131
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• 2017

For structural health monitoring of a complex shaped structure a new sensor that can compensate for the drawbacks of the current sensors such as brittleness is needed and the sensor should be highly flexible and durable. In this study a textile sensor made of polyvinylidene fluoride trifluoroethylene (PVDF-TrFE) which is a type of electroactive polymer was fabricated. And the textile sensors were applied to a complex shaped structure (an egg-box panel made of carbon/epoxy composite) for checking their feasibility of structural health monitoring. To correlate the collapse response with failure mechanisms of the structure the multiply-interrupted compressive test was carried out. During the test, the textile sensors succeeded to prove their applicability for damage detection (crack initiation) by generating electric voltages (0.05 V-0.25 V) in the real time.

• The Korean Journal of Nuclear Medicine
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• v.23 no.1
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• pp.19-25
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• 1989

To assess the usefulness of myocardial SPECT imaging to detect post-myocardial infarction ventricular aneurysms, we analyzed the Technetium-99m MIBI myocardial SPECT images of 16 patients with anterior and/or apical infarction, 9 had the previously reported findings of failure of convergence of the left ventricular walls toward the apex on SPECT images and 8 of them also had ventricular aneurysms. The ventriculography of the 2 patients with mixed pattern revealed 1 case of ventricular aneurysm and 1 case without aneurysm. Among the remaining 5 pateints with converging pattern, none had ventricular aneurysm. Of the other 11 pateints with inferior and/or lateral wall infarction, 1 patient had ventricular aneurysm and the SPECT image couldn't detect the aneurysm. $Department of Internal Medicine, College of Medicine, Seoul National University$ myocardial SPECT images for the detection of ventricular aneurysm had a sensitivity of 90 %, a specificity of 88%, and an accuracy of 89%. Thus we could get the information about presence of ventricular aneurysm as well as the status of the myocardial perfusion from the Tc-99m MIBI myocardial SPECT images.

• Journal of Korean Society of societal Security
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• v.1 no.2
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• pp.61-66
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• 2008

More than 70% of Korea consists of mountainous area and during the construction of roads and railroads many cut-slopes are inevitably formed. A number of environmental factors, such as the rainy season and frost heave during winter/thaw during spring, can result in rock falls and landslides. The failure of slopes is increasing every year and can cause damage to vehicles, personal injury and even fatality. In order to help protect people and property, there is a need for real-time monitoring systems to detect the early stages of slope failures. In this respect, the GMG has been using Translation Rotation Settlement (TRS) sensor units installed on slopes to monitor movement in real-time. However, the data lines of this system are vulnerable and the whole system can be damaged by a single lightning strike. In order to overcome this, GMG have proposed the use of Ubiquitous Sensor Networks (USN). The adoption of a USN system in lieu of data cables can help to minimize the risk of lightning damage and improve the reliability of slope monitoring systems.

• Communications for Statistical Applications and Methods
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• v.17 no.5
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• pp.689-696
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• 2010

Interval-censored data are commonly found in studies of diseases that progress without symptoms, which require clinical evaluation for detection. Several techniques have been suggested with independent assumption. However, the assumption will not be valid if observations come from clusters. Furthermore, when the cluster size relates to response variables, commonly used methods can bring biased results. For example, in a study on lymphatic filariasis, a parasitic disease where worms make several nests in the infected person's lymphatic vessels and reside until adulthood, the response variable of interest is the nest-extinction times. Since the extinction times of nests are checked by repeated ultrasound examinations, exact extinction times are not observed. Instead, data are composed of two examination points: the last examination time with living worms and the first examination time with dead worms. Furthermore, as Williamson et al. (2008) pointed out, larger nests show a tendency for low clearance rates. This association has been denoted as an informative cluster size. To analyze the relationship between the numbers of nests and interval-censored nest-extinction times, this study proposes a joint model for the relationship between cluster size and clustered interval-censored failure data.