• The Journal of Internal Korean Medicine
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• v.42 no.6
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• pp.1356-1365
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• 2021

This study examined the effectiveness of Korean medical treatment in a patient with persistent drug-induced parkinsonism after drug discontinuation. The changes in symptoms were assessed using the unified parkinson's disease rating scale (UPDRS), postural instability-gait disturbance (PIGD) score, and the 20 m gait time and steps. After 22 days of hospitalization, the UPDRS, PIGD score, and 20 m gait time and steps showed clinically significant improvement. The improvement persisted after discharge. This study indicated that Korean medical treatment could be an effective alternative therapy for treating persistent drug-induced parkinsonism after drug discontinuation.

• Journal of Practical Agriculture & Fisheries Research
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• v.12 no.1
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• pp.63-75
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• 2010

United Nations Environment Program adopted a global binding agreement to regulate the production and distribution for the persistent organic pollutants (POPs) in May 22, 2001. The agreement took its effectuation with the ratification of 59 countries from the approval of 151 countries in May 17, 2004. After the approval on the binding agreement in October 4, 2001, South Korea performed systematic investigation for the ready of ratification on the convention with country-specific exemption for some chemical substances. Case study with documentary examination and fact-finding survey found some potential problem for 5 chemical substances such as chlordane, dichloro diphenyl trichloroethane (DDT), hexachlorobenzenes (HCB), heptachlor, polychlorinated biphenyls (PCBs). However, subsequent investigation with more detailed degree showed the possibility for the ratification with no country-specific exemption.

• Geomechanics and Engineering
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• v.28 no.2
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• pp.117-133
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• 2022

Determination of the mechanical behaviour of jointed rock masses has been a challenge for rock engineers for decades. This problem is more pronounced for non-persistent jointed rock masses due to complicated interaction of rock bridges on the overall behaviour. This paper aims to study the effect of a non-persistent joint set configuration on the mechanical behaviour of rock materials under both uniaxial and biaxial compression tests using a discrete element code. The numerical simulation of biaxial compressive strength of rock masses has been challenging in the past due to shortcomings of bonded particle models in reproducing the failure envelope of rock materials. This problem was resolved in this study by employing the flat-joint contact model. The validity of the numerical model was investigated through a comprehensive comparative study against physical uniaxial and biaxial compression experiments. Good agreement was found between numerical and experimental tests in terms of the recorded peak strength and the failure mode in both loading conditions. Studies on the effect of joint orientation on the failure mode showed that four zones of intact, transition to block rotation, block rotation and transition to intact failure occurs when the joint dip angle varies from 0° to 90°. It was found that the applied confining stress can significantly alter the range of these zones. It was observed that the minimum strength occurs at the joint dip angle of around 45 degrees under different confining stresses. It was also found that the joint orientation can alter the post peak behaviour and the lowest brittleness was observed at the block rotation zone.

• Analytical Science and Technology
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• v.22 no.2
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• pp.119-127
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• 2009

This study was carried out to investigate the distribution characteristics of persistent organic pollutants in incineration residues at industrial waste incinerators and municipal solid waste incinerators, which were analyzed by the official analytical method for the endocrine disrupting chemicals and the waste. Seven of 12 persistent organic pollutants were quantitatively analyzed by GC-MSD (SIM-mode). Hexachlorobenzene was detected in 21 samples among 44 incineration residues. The level of hexachlorobenzene was 0.132-8.138 ng/g in incineration residues, 0.195-5.765 ng/g in fly ash at industrial waste incinerators, 0.270-1.828 ng/g in bottom ash and 0.154-50.643 ng/g in fly ash at municipal solid waste incinerators, respectively.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.184-188
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• 2022

Persistent trigeminal artery (PTA) represent an unusual remnant of the fetal carotid-basilar anastomosis. Persistent trigeminal artery variant (PTAV) is a rare anastomosis between the internal carotid artery and cerebellar artery, without an interposing basilar artery segment. We report the case of 49-year-old female with an incidentally discovered, rare variation of PTA that directly terminated in the ipsilateral superior cerebellar artery. The variation was observed on CT angiography, digital subtraction angiography, and MR angiography. Additionally, we reviewed the embryogenesis of PTA and PTAV and discussed the clinical implications of this variation.

• Korean Circulation Journal
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• v.53 no.10
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• pp.677-689
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• 2023

Background and Objectives: There is limited evidence regarding machine-learning prediction for the recurrence of atrial fibrillation (AF) after electrical cardioversion (ECV). This study aimed to predict the recurrence of AF after ECV using machine learning of clinical features and electrocardiograms (ECGs) in persistent AF patients. Methods: We analyzed patients who underwent successful ECV for persistent AF. Machine learning was designed to predict patients with 1-month recurrence. Individual 12-lead ECGs were collected before and after ECV. Various clinical features were collected and trained the extreme gradient boost (XGBoost)-based model. Ten-fold cross-validation was used to evaluate the performance of the model. The performance was compared to the C-statistics of the selected clinical features. Results: Among 718 patients (mean age 63.5±9.3 years, men 78.8%), AF recurred in 435 (60.6%) patients after 1 month. With the XGBoost-based model, the areas under the receiver operating characteristic curves (AUROCs) were 0.57, 0.60, and 0.63 if the model was trained by clinical features, ECGs, and both (the final model), respectively. For the final model, the sensitivity, specificity, and F1-score were 84.7%, 28.2%, and 0.73, respectively. Although the AF duration showed the best predictive performance (AUROC, 0.58) among the clinical features, it was significantly lower than that of the final machine-learning model (p<0.001). Additional training of extended monitoring data of 15-minute single-lead ECG and photoplethysmography in available patients (n=261) did not significantly improve the model's performance. Conclusions: Machine learning showed modest performance in predicting AF recurrence after ECV in persistent AF patients, warranting further validation studies.

• Clinical and Experimental Pediatrics
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• v.57 no.5
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• pp.211-216
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• 2014

Asthma comprises a heterogeneous group of disorders characterized by airway inflammation, airway obstruction, and airway hyperresponsiveness (AHR). Airway inflammation, which induces AHR and recurrence of asthma, is the main pathophysiology of asthma. The fractional exhaled nitric oxide (FeNO) level is a noninvasive, reproducible measurement of eosinophilic airway inflammation that is easy to perform in young children. As airway inflammation precedes asthma attacks and airway obstruction, elevated FeNO levels may be useful as predictive markers for risk of recurrence of asthma. This review discusses FeNO measurements among early-childhood wheezing phenotypes that have been identified in large-scale longitudinal studies. These wheezing phenotypes are classified into three to six categories based on the onset and persistence of wheezing from birth to later childhood. Each phenotype has characteristic findings for atopic sensitization, lung function, AHR, or FeNO. For example, in one birth cohort study, children with asthma and persistent wheezing at 7 years had higher FeNO levels at 4 years compared to children without wheezing, which suggested that FeNO could be a predictive marker for later development of asthma. Preschool-aged children with recurrent wheezing and stringent asthma predictive indices also had higher FeNO levels in the first 4 years of life compared to children with wheezing and loose indices or children with no wheeze, suggesting that FeNO measurements may provide an additional parameter for predicting persistent wheezing in preschool children. Additional large-scale longitudinal studies are required to establish cutoff levels for FeNO as a risk factor for persistent asthma.

• Journal of Digital Convergence
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• v.10 no.5
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• pp.37-51
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• 2012

The purpose of this study is to approach information security from a more comprehensive perspective. Particularly, information countermeasures includes a technological tool for end users, thereby increasing the end users' technological stresses. Based on the technostress framework, we investigate a effect of security awareness training on technostress, and also examine a effect of technostress on the persistent security compliance. Results showed that security awareness training influenced on techno-overload and techno-uncertainty. We also found that techno-overload and techno-uncertainty have a significant effect on the persistent security compliance. Conclusion and implications are discussed.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.5
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• pp.481-494
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• 2005

The monitoring of persistent organic pollutants (POPs) in the atmosphere is a basis for the study of the fate of POPs in multimedia environments. Recently, passive air samplers (PASs) for POPs have been developed. In this paper, we deal with the principle, properties, and applications of the PAS. The principle of PAS, which has no pump, is physical sorption of semi-volatile organic chemicals on various sorbent materials. The PAS is much smaller than a high-volume air sampler and does not need electricity. These properties of the PAS make it possible to conduct various-scaled environmental monitoring all over the world including the Arctic and Antarctic, but the major disadvantage of PAS is its long sampling periods up to 2 years. To date, four kinds of PAS have been developed: polyurethane foam (PUF), polymer-coated glass (POG), semi-permeable membrane devices (SPMDs), and XAD resin-based PAS. Among them, SPMDs have been commercialized and are most widely used now. Meanwhile, the POPs emitted from China have a large potential to influence the levels and fates of POPs in Korea. Since characteristics of PAS are quite useful to monitor long-range transport of POPs, the use of PAS is highly recommended.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1443-1449
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• 2003

Primary goal of adaptive observers would be to estimate the true states of a plant. Identification of unknown parameters is of secondary interest and is achieved frequently with the persistent excitation condition of some regressors. Nevertheless, two problems are linked to each other in the classical approaches to adaptive observers; as a result, we get a good state estimate once after a good parameter estimate is obtained. This paper focuses on the state estimation without parameter identification so that the state is estimated regardless of persistent excitation. In this direction of research, Besancon (2000) recently summarized that most of adaptive observers in the literature share one common canonical form, in which unknown parameters do not affect the unmeasured states. We enlarge the class of linear systems from the canonical form of (Besancon, 2000) by proposing an adaptive observer (with additional dynamics) that allows unknown parameters to affect those unmeasured states. A recursive algorithm is presented to design the proposed dynamic observer systematically. An example confirms the design procedure with a simulation result.