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Objective: Adrenocorticotropic hormone (ACTH) and β-endorphin are pituitary neuro-peptides released by acute stress. We determined why the prognosis of patients with subarachnoid hemorrhages (SAH) due to aneurysmal rupture is not always dependent on the Hunt–Hess grading system (HHS) and delta-National Institutes of Health Stroke Scale (NIHSS), while studying endogenous neuropeptides, including ACTH and β-endorphin.Methods: We analyzed blood samples collected from patients with SAH (SAH group; n=37) and those with unruptured intracranial aneurysms (control group; n=37). Blood sampling was performed before any procedure or chemical agents administration. The results of ACTH and β-endorphin measurements were compared using the delta-NIHSS and HHS. The data were analyzed using descriptive statistics, independent samples t-tests, and Pearson’s correlations.Results: Of the 18 patients with low-grade HHS, 13 had low delta-NIHSS and five showed high delta-NIHSS. Of the 19 patients with high-grade HHS, the delta-NIHSS was ≥14 in the other five patients. ACTH concentration was high (497.3 pg/mL) in five patients with high-grade HHS and high delta-NIHSS. β-endorphin concentration was high (159.7 pg/mL) in 13 patients with low-grade HHS and low delta-NIHSS.Conclusions: High ACTH levels in patients with massive bleeding and poor neurological status suggests increasing ACTH secretion in response to bleeding stress, which may aggravate neurological status. Contrary to ACTH, high β-endorphin levels in patients with low-grade HHS implied the involvement of additional factors in predicting fair outcomes related to low delta-NIHSS. These results may provide insight into the varying prognostic potential of HHS in SAH patients.

Atrial fibrillation (AF) is associated with various major adverse cardiac events such as ischemic stroke, heart failure, and increased overall mortality. However, its association with lethal ventricular arrhythmias such as ventricular tachycardia (VT), ventricular flutter (VFL), and ventricular fibrillation (VF) is controversial. We conducted this study to determine whether AF can increase the risk of VT, VFL, and VF. We utilized the Korean National Health Insurance Service database for this nationwide population-based study. This study enrolled people who underwent a nationwide health screen in 2009 for whom clinical follow-up data were available until December 2018. Primary outcome endpoint was the occurrence of VT, VFL, or VF in people who were and were not diagnosed with new-onset AF in 2009. We analyzed a total of 9,751,705 people. In 2009, 12,689 people were diagnosed with new-onset AF (AF group). The incidence (events per 1000 person-years of follow-up) of VT, VFL, and VF was 2.472 and 0.282 in the AF and non-AF groups, respectively. After adjustment for covariates, new-onset AF was associated with 4.6-fold increased risk (p

The characteristics of hypertension in pre- and postmenopausal women are different. Hypertension is a known risk factor for new-onset atrial fibrillation (AF), but its interaction with the menopause state is not fully established. We investigated whether menopause influences the adverse impact of high blood pressure on new-onset AF using a nationwide population-based cohort in Korea. People who underwent both a national health check-up and national cancer screening program were included in this study. A total of 3 280 834 women were assessed with 23 781 070 person*year follow-up data. Menopause was observed in 1 439 161 women. The risk of new-onset AF and blood pressure showed a linear relationship in premenopausal women ( P P for interaction

Inherited arrhythmia (IA) is one of the main causes of sudden cardiac death (SCD) in young people, and is reported to be a more prevalent cause of SCD in Asia than in Western countries. IAs are a group of genetic disorders caused by mutations in genes encoding cardiac ion channels, leading to electrophysiological characteristics that often occur in the absence of structural abnormalities. Channelopathies, such as long QT syndrome and Brugada syndrome, carry a potential risk of life-threatening ventricular tachyarrhythmias that predispose to SCD, although early prediction and prevention of the risk remain challenging. Recent advances in genetic testing have facilitated risk stratification as well as a precise diagnosis for IA, despite ongoing debates about the implications. Herein, we provide epidemiological data, a pathophysiological overview, and the current clinical approach to IAs related to SCD. In addition, we review the general issues arising from genetic testing for IAs.

Acute cerebral infarctions usually demonstrate hypodensity on non-contrast computed tomography (CT). However, in some cases, cerebral infarctions may appear to be isodense on imaging conducted during the subacute stage (2-3 weeks after onset). This phenomenon was previously called the fogging effect and has also been reported in magnetic resonance imaging. It is generally reported at T2 image, but can also be observed in diffusion-weighted image (DWI). We report three cases of the fogging effect demonstrated on CT and DWI that was conducted in the subacute stage of ischemic cerebral infarcts. The fogging effect can result in incorrect judgment during the diagnosis and treatment of cerebral infarction patients in the subacute stage. Therefore, it is important that clinicians anticipate this occurrence and necessitates the development of better detection methodologies.

Aims There are several non-genetic risk factors for new-onset atrial fibrillation, including age, sex, obesity, hypertension, diabetes, and alcohol consumption. However, whether these non-genetic risk factors have equal significance among different age groups is not known. We performed a nationwide population-based analysis to compare the clinical significance of non-genetic risk factors for new-onset atrial fibrillation in various age groups. Methods and results A total of 9,797,409 people without a prior diagnosis of atrial fibrillation who underwent a national health check-up in 2009 were included. During 80,130,090 person-years of follow-up, a total of 196,136 people were diagnosed with new-onset atrial fibrillation. The impact of non-genetic risk factors on new-onset atrial fibrillation was examined in different age groups. Obesity, male sex, heavy alcohol consumption, smoking, hypertension, diabetes and chronic kidney disease were associated with an increased risk of new-onset atrial fibrillation. With minor variations, these risk factors were consistently associated with the risk of new-onset atrial fibrillation among various age groups. Using these risk factors, we created a scoring system to predict future risk of new-onset atrial fibrillation in different age groups. In receiver operating characteristic curve analysis, the predictive value of these risk factors ranged between 0.556 and 0.603, and no significant trends were observed. Conclusions Non-genetic risk factors for new-onset atrial fibrillation may have a similar impact on different age groups. Except for sex, these non-genetic risk factors can be modifiable. Therefore, efforts to control non-genetic risk factors might have relevance for both the young and old.

Convention hand polishing, which is widely used for delayering, is becoming increasingly difficult as metal lines and stacks in semiconductor devices get thinner. For one thing, endpointing at the exact targeted layer and region of interest is a major challenge. The presence of cobalt and its propensity to oxidize, thus complicating electrical measurements, is another challenge. In this study, the authors demonstrate an alternative delayering method based on plasma focused ion beam (PFIB) milling aided by DX gas. The workflow associated with the new method is more efficient than that of conventional hand polishing and can help prevent cobalt oxidation.

This article addresses the approximate multi-objective optimum design of an automotive hydraulic steering system based on a multi-body dynamics analysis. The design problem of a hydraulic steering ...

BackgroundTuberculosis (TB) survivors experience post-TB lung damage and ventilatory function disorders. However, the proportions of obstructive and restrictive ventilatory disorders as well as normal ventilation among post-TB subjects are unknown. In addition, the impacts of ventilatory disorder and its severity on respiratory symptoms, physical activity limitations, and the quality of life in post-TB subjects remain unclear.MethodsSubjects who participated in the Korean National Health and Nutritional Examination Survey 2007–2016 were enrolled in this study. We evaluated the impact of each ventilatory disorder and its severity on respiratory symptoms, physical activity limitations, and quality of life (measured by the EuroQoL five dimensions questionnaire [EQ-5D] index values) in post-TB subjects.Results Among 1,466 post-TB subjects, 29% and 16% had obstructive ventilatory disorders and restrictive ventilatory disorders, respectively. Mild and moderate obstructive ventilatory disorders were not associated with respiratory symptoms, physical activity limitation, or EQ-5D index value compared with normal ventilation; however, severe obstructive ventilatory disorders were associated with more respiratory symptoms (adjusted odds ratio [aOR] = 5.82, 95% confidence interval [CI] = 2.80–12.10), more physical activity limitation (aOR = 92.20, 95% CI = 16.33–520.62), and decreased EQ-5D index (adjusted coefficient = -0.055, 95% CI = -0.096 – -0.013) compared with normal ventilation. Mild restrictive ventilatory disorders were associated with more respiratory symptoms (aOR = 1.95, 95% CI = 1.07–3.56) compared with normal ventilation, while moderate (aOR = 9.17, 95% CI = 1.02–82.22) and severe restrictive symptoms (aOR = 9.17, 95% CI = 1.02–82.22) were associated with physical activity limitation compared with normal ventilation.ConclusionAmong post-TB subjects, 29% and 16% developed obstructive and restrictive ventilatory disorders, respectively. Severe obstructive ventilatory disorder was associated with more respiratory symptoms, more physical activity limitation, and poorer quality of life, while severe restrictive ventilatory disorder was associated with more physical activity limitations.

Larger left atrial appendage (LAA) volume is associated with a higher risk of late recurrence (LR) in patients undergoing radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). However, it is unclear whether LAA volume predicts LR, independent of established risk factors. We sought to evaluate the value of LAA volume in predicting LR after RFCA for AF and to develop a score prediction model including LAA volume for these patients. We retrospectively studied 992 patients who underwent RFCA for AF and cardiac computed tomography before RFCA at a single center. At 3 years after RFCA, 362 patients (36.5 %) experienced recurrence. The multivariate Cox regression model showed that age ≥ 75 years (10 points), non-paroxysmal AF (9 points), diabetes mellitus (4 points), left atrial volume index (1 point per 10 ml/m2 rounded to the nearest integer), and the second (4.7 to < 7 ml/m2; 4 points) and third (≥ 7 ml/m2; 5 points) tertiles of the LAA volume index were independent risk factors LR. The above-mentioned risk factors were included in the integrated score model, and the C-index of the proposed score model was 0.715 (95 % confidence interval [CI] 0.679–0.752). LAA volume is an independent predictor of LR and the predictive model including LAA volume showed good discrimination power. These findings provide evidence for the inclusion of LAA volume in the risk stratification for AF recurrence in patients undergoing RFCA for AF.

Premature ventricular contraction (PVC) and atrial fibrillation (AF) are common arrhythmias affecting 1–2% of the general population. During PVC, retrograde ventriculo-atrial activation can occur and act like an atrial ectopy. However, the clinical significance of this phenomenon is not fully understood. We aimed to elucidate whether the clinical diagnosis of PVC can increase the risk of new-onset AF. We performed a nationwide population-based analysis using the Korean National Health Insurance Service database. A total of 9,537,713 people without prior history of PVC and AF were identified. Among these people, 4135 developed PVC in 2009, and people with and without PVC were followed until 2018. People who had PVC showed an increased risk of new-onset AF as compared with people without PVC (hazard ratio [HR] = 2.705; 95% confidence interval [CI] = 2.428–3.013; p

Premature ventricular contraction (PVC), a common arrhythmia affecting 1–2% of the general population, has been considered to have a benign clinical course. However, people with PVC often develop heart failure and ventricular arrhythmias such as ventricular tachycardia. We aimed to clarify the risk of heart failure and lethal ventricular arrhythmias in people with PVC. The Korean National Health Insurance Service database was used for this study. People who underwent nationwide health check-ups in 2009 were enrolled in this study and clinical follow-up data until December 2018 were analyzed. Newly diagnosed PVC in 2009 (≥ 1 inpatient or outpatient claim) were identified and cumulative incidence of heart failure (≥ 1 inpatient claim) and ventricular arrhythmias (≥ 1 inpatient or outpatient claim) were compared. A total of 4515 people were first diagnosed with PVC in 2009 among 9,743,582 people without prior history of PVC, heart failure, or ventricular arrhythmias. People with newly diagnosed PVC in 2009 had a significantly higher incidence of heart failure compared to those without PVC [adjusted hazard ratio (HR) 1.371; 95% confidence interval (CI) 1.177–1.598; p p < 0.001). Age and chronic kidney disease had significant interactions with PVC. In conclusion, the incidence of heart failure and ventricular arrhythmia was significantly increased in people with PVC. Outpatient follow-up of people with PVC can be helpful to detect early signs of heart failure or advanced forms of ventricular arrhythmia.

INTRODUCTION Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients. Velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the association between radiofrequency catheter ablation (RFCA) and LAA hemodynamics measured by MRI. METHODS AND RESULTS Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.93 ± 32.92 and 72.00 ± 34.82 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 14.63 ± 40.67 vs. 30.03 ± 35.37; p

Objectives This study aimed to compare the risk of late recurrence in patients with and without early recurrence. Background Early recurrence of atrial fibrillation (AF) or atrial tachycardia (AT) after radiofrequency catheter ablation (RFCA) in AF patients is known to be a transient phenomenon. The theoretical basis of the blanking period is based on such observations. However, the clinical implications of early recurrence need further validation. Methods Consecutive RFCA cases in a tertiary hospital were analyzed. Early recurrence was defined as any AT or AF event occurring within 90-days post-RFCA. Early recurrence as AT and AF were also analyzed separately. Results A total of 3,120 patients underwent RFCA. Early recurrence occurred in 751 patients (24.1%). Patients who experienced early recurrence had a larger left atrium, worse hemodynamics in the left atrial appendage, and a higher prevalence of nonparoxysmal AF and heart failure. Among patients who experienced early recurrence, 69.6% of patients eventually had late recurrence. Early recurrence was associated with a 4.3- and 3.6-fold increase in the risk of late recurrence after single and multiple procedures, respectively. After multivariate adjustment, early recurrence was an independent risk factor for late recurrence with 3.6- and 2.8-fold increase in the risk of late recurrence after single and multiple procedures, respectively. Early recurrence AT had a lower risk of late recurrence compared with early recurrence AF. Conclusions Early recurrence was a reliable predictor for late recurrence. The clinical significance of the blanking period in the current guidelines may need to be revisited.

Aim Although studies on monitoring modalities have been previously conducted, they have shown differences in the values of preoperative and intraoperative monitoring. This study sought to compare preoperative and intraoperative electrophysiologic values. Material and methods A retrospective medical record review was conducted on patients who underwent brain and spine surgery between January 2014 and July 2018. Patients underwent preoperative electrophysiologic monitoring within a week before the operation and intraoperative monitoring during the surgery. Monitoring parameters included the onset latency (msec) and amplitude (mV) of motor evoked potential (MEP), somatosensory evoked potential (SEP), electroneuronography, and brainstem auditory evoked potential (BAEP). Results The latency of the MEP and SEP were significantly prolonged while the amplitude was decreased during operation. Specifically, patients with abnormal findings in their preoperative assessments showed more prominent differences compared to those with normal findings. However, there was no significant difference between preoperative and intraoperative results based on which side of the hemisphere was affected or unaffected. Unlike the MEP and SEP parameters, there were no significant changes in the facial electroneuronography and BAEP parameters. Conclusion There were differences in the preoperative and intraoperative monitoring parameters. Further studies are necessary to understand the underlying mechanisms behind these changes during surgery.

The Cockcroft-Gault (CG) formula is recommended to guide clinicians in the choice of the appropriate dosage for direct oral anticoagulants (DOACs). However, the performance of the CG formula varies depending on the patient&rsquo, s age, weight, and degree of renal function. We aimed to compare the validity of the CG formula with that of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) formulae for dosing DOACs. A total of 6268 consecutive patients on anticoagulants for atrial fibrillation (AF) were retrospectively investigated. Among underweight and elderly patients, the CG formula underestimated renal function compared with the non-CG formulae. However, the concordant rate of drug indications between the CG and the non-CG formulae was approximately 94%. On-label uses under the three formulae were associated with a lower risk of major bleeding (but not thromboembolism) compared to warfarin. Although we found differences in estimating renal function and the proportions of drug indications between the CG and non-CG formulae, the risks of thromboembolism and major bleeding were similar to those with warfarin regardless of which formula was used.

Background The successful promotion of facility births in low and middle-income countries has not always resulted in improved neonatal outcome. We evaluated key signal functions pertinent to Level II neonatal care to determine facility readiness to care for high risk/ small and sick newborns. Method Facility readiness for care of high risk/ small and sick babies was determined through self-evaluation using a pre-designed checklist to determine key signal functions pertinent to Level II neonatal care in selected referral hospitals in Uganda (10), Indonesia (4) and India (2) with focus on the Sub-Saharan country with greater challenges. Results Most facilities reported having continuous water supply, resources for hand hygiene and waste disposal. Delivery rooms had newborn corners for basic neonatal resuscitation, but few practiced proper reprocessing of resuscitation equipment. Birth weight records were not consistently maintained in the Ugandan hospitals. In facilities with records of birth weights, more than half (51.7%) of newborns admitted to the neonatal units weighed 2500 g or more. Neonatal mortality rates ranged from 1.5 to 22.5%. Evaluation of stillbirths and numbers of babies discharged against medical advice gave a more comprehensive idea of outcome. Kangaroo Mother Care was practiced to varying extents. Incubators were more common in Africa while radiant warmers were preferred in Indian hospitals. Tube feeding was practiced in all and cup feeding in most, with use of human milk at all sites. There were proportionately more certified pediatricians and nurses in Indonesia and India. There was considerable shortage of nursing staff, (worst nurse –bed ratio ranging from 1 to 15 in the day shift, and 1 to 30 at night). There was significant variability in facility readiness, as in data maintenance, availability of commodities such as linen, air -oxygen blenders and infusion pumps and of infection prevention practices. Conclusions Referral neonatal units in LMIC have challenges in meeting even the basic level II requirements, with significant variability in equipment, staffing and selected care practices. Facility readiness has to improve in concert with increased facility births of high risk newborns in order to have an impact on neonatal outcome, and on achieving Sustainable Development Goals 3.2.2. Electronic supplementary material The online version of this article (10.1186/s40748-019-0105-9) contains supplementary material, which is available to authorized users.

83 Copyright c 2016 The Korean Association of Internal Medicine This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Received: 2014. 6. 17 Revised: 2014. 8. 21 Accepted: 2014. 10. 13

OBJECTIVE An advantage of surgical treatment over conservative treatment of spontaneous intracerebral hemorrhage (ICH) is controversial. Recent reports suggest that contrast extravasations on CT angiography (CTA) might serve as a crucial predictor of hematoma expansion and mortality. The purpose of this study was aimed at investigating the efficacy of surgical treatment in patients with spot sign positive ICH. METHODS We used our institutional medical data search system to identify all adult patients who admitted for treatment of ICH between January 1, 2007 and January 31, 2012. Patients were classified two groups into a surgical group (n=27) and a conservative treatment group (n=28). Admission criteria were the following: age 20-79 years, spontaneous supratentorial ICH, Glasgow Coma Score Ranging from 9 to 14, ICH volume ≥20 mL, and treatment within 24 hours. RESULTS Fifty-five patients were analyzed. There was no significant difference in the ICU stay between the conservative treatment group (7.36±3.66 days) and the surgical treatment group (6.93±2.20 days; p=0.950). There was a significant difference in the in-hospital stay between the conservative treatment group (13.93±8.87 days) and the surgical treatment group (20.33±6.37 days; p=0.001). Overall mortality at day 90 after ICH was 36.4%; this included 16 of 28 patients (57.1%) in the conservative group and 4 of 27 patients (14.8%) in the surgical group. In univariate analysis, there was a positive effect of the surgical treatment in reducing mortality at 90 days (p=0.002), Glasgow Outcome Scale (GOS) at 90-day (p=0.006), and modified Rankin Scale (mRS) at 90-day (p=0.023). In multivariate logistic analysis, there was a significant difference in mortality (odds ratio, 0.211; 95% confidence interval, 0.049-0.906; p=0.036) between the groups at 90-day follow-up. However, there was no significant difference in GOS (odds ratio, 0.371; 95% confidence interval, 0.031-4.446; p=0.434) and mRS (odds ratio, 1.041; 95% confidence interval, 0.086-12.637; p=0.975) between the groups at 90-day follow-up. CONCLUSION In this study of surgical treatment of supratentorial ICH in patients with spot sign positive in CTA was associated with less mortality despite of long duration of in-hospital stay. We failed to show that clinical outcome benefit of surgical treatment compared with conservative treatment in patients with spot sign positive ICH.

Hemifacial spasm (HFS) is caused by tortuous offending vessels near the facial nerve root exit zone. However, the definitive mechanism of offending vessel formation remains unclear. We hypothesized that vascular angulation and tortuosity, probably caused by uneven vertebral artery blood flow, result in vascular compression of the facial nerve root exit zone. The authors observed two anatomical characteristics of the vertebrobasilar arterial system in 120 subjects in the surgical group and 188 controls. The presence of the dominant vertebral artery (DVA) and laterality of the vertebrobasilar junction (VBJ) were observed. We also analyzed the morphological characteristics of the surgical group showing the presence of DVA. The morphological characteristics were classified into three types: type I had the VBJ and DVA on the same side, type II had the VBJ within 2 mm of the midline, and type III had the VBJ opposite the DVA. The DVA was more prevalent in the surgical group than in the control group (71 % versus 54 %, P

Traumatic intracranial pseudoaneurysms occurring after blunt head injuries are rare. We report an unusual case of subarachnoid hemorrhage (SAH) caused by rupturing of the traumatic pseudoaneurysm of the internal carotid artery (ICA) bifurcation that resulted from a non-penetrating injury. In a patient with severe headache and SAH in the right sylvian cistern, which developed within 7 days after a blunt-force head injury, a trans-femoral cerebral angiogram (TFCA) showed aneurysmal sac which was insufficient to confirm the pseudoaneurysm. We obtained a multi-slab image of three dimensional time of flight (TOF) of magnetic resonance angiography (MRA). The source image of the gadolinium-enhanced MRA revealed an intimal flap within the intracranial ICA bifurcation, providing a clue for the diagnosis of a dissecting pseudoaneurysm at the ICA bifurcation due to blunt head trauma. We performed direct aneurysmal neck clipping, without neurological deficit. A follow-up TFCA did not show either aneurysm sac or luminal narrowing. We suggest that in the patient with a history of blunt head injury with SAH following shortly, multi-slab image of 3D TOF MRA can give visualization of the presence of a pseudoaneurysm.

Coil migration into the parent artery during endovascular coil embolization is a rare, but life-threatening complication, which can induce thromboembolism and result in poor outcome. A 63-year-old man was referred to Chonbuk National University Hospital emergency center due to migration of a coil for a left middle cerebral artery bifurcation unruptured aneurysm. We performed an emergency craniectomy to remove the coil migrated to the distal M2 branch and thrombus, and aneurysmal neck clipping for his aneurysm. Fortunately, at the six month follow-up, the patient did not show any noticeable neurological sequela. In case of parent artery occlusion due to coil migration an immediate recanalization should be performed by a neurovascular specialist who can provide both surgical treatment and endovascular management in order to prevent severe sequela or even death.

화학적 에너지를 전기적 에너지로 변환시켜주는 장치 중 하나인 리튬 이차전지는 에너지 밀도가 높고 자연방전이 적으며 기억효과가 없기 때문에 핸드폰, MP3, 노트북 등과 같은 모바일 기기와 인공위성과 같은 다양한 분야에 적용되고 있다. 1990년대 핸드폰과 같은 모바일 기기의 등장과 함께 리튬 이차전지의 상용화가 시작되면서 전지관련 기술은 급속도로 발전하기 시작하였다. 이후 고유가와 지구온난화로 인해 전기자동차에 대한 관심이 커지면서 차세대 에너지솔루션으로 자리매김하였다. 전기자동차용 배터리로 최근 검토되고 있는 리튬 이차전지는 기존의 모바일용으로 사용되던 리튬 이차전지보다 더 우수하고 최적화된 용량과 출력, 안전성 등의 특성을 요구하고 있다. 리튬 이차전지에 대한 요구는 전자제품과 전기자동차 등의 분야에서 시간이 갈수록 증가하고 있다. 하지만 실제 리튬 이차전지의 성능발전 속도는 시장의 요구를 완벽하게 만족시키고 있지는 못하는 수준이다. 이는 전지의 성능에 대한 검증기간과도 연결이 되는데, 일반적으로 리튬 이차전지Key Words: Lithium-Ion Battery(리튬이온전지), Current Density(전류밀도), Data Mining(데이터마이닝), Decision Tree(의사결정나무), Artificial Neural Network(인공신경망), Weight Analysis(가중치분석) 초록: 본 연구에서는 데이터 마이닝의 방법인 의사결정나무와 인공신경망을 이용하여 리튬 이차전지의 전류밀도 특성에 대해 핵심 설계 인자를 도출하고 비교하였다. 먼저 의사결정나무-인공신경망 모델을 이용한 설계방법으로, 비선형성을 나타내는 초기 극판 설계인자들 중에 의사결정나무 모델을 통해 주요 설계 인자를 도출한 다음 인공신경망을 이용하여 설계인자들 간의 중요도와 전류밀도와의 가중치 분석을 수행하였다. 두 번째 방법은 인공신경망 모델만을 이용한 방법으로, 초기 설계인자들을 별도의 주요인자 도출 과정 없이 모두 인공신경망을 구축하는데 사용하여 전류밀도와의 연관성 및 가중치를 분석하였다. Abstract: In the present study, a decision tree and artificial neural network were used to determine critical design parameters for lithium ion batteries and compare their performances. First, a design method that used a decision tree-artificial neural network model was used to determine the major design factors among early pole plate design factors that showed nonlinearity. Then, the artificial neural network was used to implement a weighted value analysis of the importance of the design factors and their effect on the current density. The second method involved the use of an artificial neural network model to construct artificial networks without separate determinations of the major early design factors to analyze the connections and weighted values related to the current density.

The Doctor Blade is mounted to a toner cartridge and applies consistent pressure to the development roller. This part enables the toner adhering to the development roller to form a layer of consistent thickness. The contact pressure between the development roller and the Doctor Blade is an important factor determining not only image quality, but also toner cartridge durability. In this study, test points were extracted using a central composite design method and contact analysis was carried out using NASTRAN, an FEM tool. In addition, based on measurements of toner weight by unit area and image concentrations through sample production and experiments under various conditions, approximated models were derived using the response surface method. With approximated modeling of contact pressure set as an objective function, and approximated modeling in relation to experimental values set as constraint conditions, the optimal solution was derived by applying the optimization technique of genetic algorithms. Moreover, by applying the optimal solution to an actual sample, its reliability was verified through comparison of the optimal results of genetic algorithms with the actual solutions.

For analysis of greenhouse environments using big data, measuring data should be continuously collected without data loss caused by sensing and networking problems. Recently, deep learning approach has been widely used for precision agriculture. However, in order to use deep learning methods, the enormous amount of reliable data is necessary. The objective of this study is to compare the interpolation accuracy of greenhouse environment data using multilayer perceptron (MLP) with existing statistical and machine learning methods. Linear and spline interpolations were selected as statistical methods, and linear models, MLP and random forest (RF) were selected as machine learning methods. The raw data used for interpolation were greenhouse environment data collected from October 2, 2016 to May 31, 2018 where Irwin mango (Mangifera indica L. cv. Irwin) trees were cultivated. As a result, the linear interpolation method showed the highest R2 (average 0.96) in short-term data loss conditions, but the MLP showed R2 = 0.95. However, in long-term data loss conditions, the accuracies of the linear, spline, and regression interpolations decreased, but the accuracies of the MLP and RF remained stable. However, MLP showed better accuracies than RF. Therefore, the MLP was better suited to interpolating greenhouse environment data because short- and long-term data loss actually occurred simultaneously when collecting greenhouse environment data. The trained MLP showed the high accuracy in both short- and long-term data interpolations, indicating that MLP can also be complementally used with existing methods. The trained MLP accurately estimated the missing data in the greenhouse and will contribute to the analysis of big data collected from greenhouses.

The global business circumstances are rapidly changed so the design optimization which is related to quality engineering is needed than ever. In case of the robot casting the tolerance of material and variation of material property are the main cause of quality issues and such a reason quality based design optimization is urgently needed. Robust design gives robustness to the objective function considering tolerance and variation of material property while in the reliability based design, they are controlled by probability of constraint violation. In this study, two other quality engineering methods are done about same robot casting and compare with each other. During that process, some technical theory is applied. Sensitivity analysis with the design of experiments is used for reducing control design variable, approximation with central composite design is used to make objective and constraint functions. Genetic algorithm and search direction method is applied to make robust design optimization. For reliability based design optimization, the performance measure approach method is used. Comparing two other quality engineering method means that the robustness of objective and constraint functions which is resulted from robust design has certain results in aspect of reliability which is controlled by probability of constraint violation.

The original version of the moving least squares method (MLSM) does not always ensure solution feasibility for nonlinear and/or non-convex functions in the context of meta-model-based approximate optimization. The paper explores a new implementation of MLSM that ensures the conservative feasibility of Pareto optimal solutions in non-dominated sorting genetic algorithm (NSGA-II)-based approximate multi-objective optimization. We devised a `conservative and feasible MLSM' (CF-MLSM) to realize the conservativeness and feasibility of multi-objective Pareto optimal solutions for both unconstrained and constrained problems. We verified the usefulness of our proposed approach by exploring strength-based sizing optimization of an automotive knuckle component under bump and brake loading constraints.

Article history: Creation of a stress relief groove is a fairly simple yet high-performance method. During the application of this method, it is important to consider the location and size of thegroove in order to achieve better performance. Consequently, this research proposes an approach for optimizing the application of the stress relief groove method to a press-fitted assembly. In a boss design, the position and diameter of the groove are configured as design variables and the design of experiments is applied. Based on this information, a 3D model is built and analyzed using the finite element analysis software ABAQUS. Meta-models are created using back-propagation neural networks. Then, deterministic optimization results obtained from a genetic algorithm are compared with the results of the finite element analysis. The temperature sensitivity of the optimized model is analyzed, and finally, reliability-based design optimization is conducted for enhancing the design quality.

The objective of this study is to propose the effective method of reducing the maximum contact pressure at the contact edge of press-fitted shaft by optimizing the location and the size of stress relief groove in hub face. Finite element analysis was performed in order to determine the contact pressure and stress state on a press-fitted assembly and optimization were applied to select optimal size and location of stress relief groove. In order to reduce the cost of optimization design, approximation optimization method is used and the optimum results obtained by Sequential Quadratic Programming and genetic algorithm are compared. Optimized results show that the maximum contact pressure at the contact edge of press-fitted shaft with optimal stress relief groove decreased about 30%. And the both optimization algorithms can effectively reduced the maximum contact pressure at the contact edge of press-fitted shaft.

A method to simulate rolling contact wear in a rail surface was developed using the finite elements method and numerical analysis. A two-dimensional finite elements model was used in order to reduce the calculation time and boundary conditions to prevent excessive deformation of a wheel and a rail were applied. A numerical analysis of rail wear at rolling contact was predicted using the Archards equation. In addition, the characteristics of rail wear with the increasing speed of vehicle were analyzed. Results show that there was not a large difference in the depths of wear on the rail head with increasing vehicle speed, but the wear on the rail gauge corner increased with increasing vehicle speed.

A valve is a marine structure that is subjected to multiple seawater loads. Therefore, it is necessary to define the kind of loads applied to it to confirm whether the structure has sufficient strength. In this research, we aimed to find the optimal solution for the stress and deformation of valves under various loads. We first selected design variables and implement a finite element analysis according to changes in the thickness of each component of a valve based on a central composite design. Next we developed a regression model of the response surface. Using this model, we calculated the optimal objective value based on NSGA-II. Finally, to confirm the correspondence between the optimal objective value and the real FEM value, we compared the optimal result and structural analysis result to verify the performance of NSGA-II.

The doctor blade is equipped in a toner cartridge and is a device to maintain the uniform thickness of a toner by controlling the pressure on the developing roller. The contact pressure between the developing roller and the doctor blade is one of the significant factors for image quality and durability of toner cartridge. The purpose of this study is to develop approximation model in order to minimize the time and cost which are needed much required in making optimal design of the doctor blade. Central composite design was used for the design of experiment and response surface design was used for approximation. The data for contact pressure were acquired through finite element analysis and data of image density and toner weight were acquired through experiment. The approximation model developed in this study has presented very high fitness.

Wear is one of the most important factors affecting the structural life of railways. In urban railways, the curved track results in more wear than tangent track. Furthermore, the wear is frequently detected in a sharply curved track. Wear leads to reduction in the durability of railway as well as increase in the risk of derailment. In a recent study, a rail grinding was suggested to enhance the dynamic performance and extend the fatigue life of rails. This paper deals with an optimum design procedure for asymmetric rail head profile wherein the design profiles of high and low rails are simultaneously determined by minimizing the wear on curved tracks. The procedure employs a genetic-algorithm-based optimization method. The dynamic performances of a train such as lateral force, derailment and vertical force are evaluated using a rail vehicle dynamics program. The optimum design is validated by comparing the initial rail profile with the optimum profile in a full-scale wear test.

Damage to wheels and rails due to wear and fatigue affects the safety and maintenance of railway vehicles. The present study optimizes profile of the wheel flange for reducing flange wear and surface fatigue on a curved track. The railway dynamic analysis program VAMPIRE is employed to calculate different loading conditions, contact pressure, wear and fatigue on the running surface of the wheel. The multi-objective optimization of minimizing both flange wear and surface fatigue is handled by a fast non-dominated sorting genetic algorithm, NSGA-II. Optimized designs yield better performance and reduced wear and fatigue compared to an initial wheel profile.

This paper presents a structural design review of a marine loading arm used for the fluid transfer of a liquid cargo from a ship or offshore plant. The marine loading arm is installed on a ship, offshore plant, or jetty in order to load or unload liquid cargo such as crude oil, liquefied natural gas (LNG), chemical products, etc. The struct ural design of this marine loading arm is obliged to comply with the design and construction specifications regulated by the oil companies and international marine forum (OCIMF). In this paper, the structural safety of the initial design for the marine loading arm is evaluated for the design load conditions required by various operational modes. The evaluated results based on a finite element analysis (FEA) are reviewed in relation to the OCIMF specifications.

Nowadays, rapidly changing and unstable global economic environments request a lot of roles to engineers. In this situation, product should be designed to make more profit by cost down and to satisfy distinguished performance comparing to other competitive ones. In this research, the optimization design of the industrial robot casting will be done. The weight and deflection have to be reduced as objective functions and stress has to be constrained under some constant value. To reduce time cost, CCD (Central Composite Design) will be used to make experimental design. And RSM (Response Surface Methodology) will be taken to make regression model for objective functions and constraint function. Finally, optimization will be done with Genetic Algorithm. In this problem, the objective functions are multiple, so NSGA-II which is brilliant and efficient for such a problem will be used. For the solution quality check, the diversity between Pareto solutions will be also checked. Key Words

The metal is frequently used in the air-conditioner frame, which must have the durability from the various external environments, but has difficulties in being manufactured for many complex shapes. On the other hand, the plastic, used as a material of injection molding, enables the realization of various shapes and the mass-production of complex ones and leads low production cost. As the air-conditioner frame becomes increasingly complex and detailed, the plastic material is highlighted as an alternative for the frame. But the product molded by plastic with a complex shape might have a noise problem. Therefore this study attempts to design the product through TRIZ in order to reduce the noise of the air-conditioner with the frame of plastic material.

The wear problem of wheel flange occurs at sharp curves of rail. This paper proposes a procedure for optimum design of a wheel profile wherein flange wear is reduced by improving an interaction between wheel and rail. Application of optimization method to design problem mainly depends on characteristics of design space. This paper compared local optimization method with global optimization according to sensitivity value of objective function for design variables to find out which optimization method is appropriable to minimize wear of wheel flange. Wheel profile is created by a piecewise cubic Hermite interpolating polynomial and dynamic performances are analyzed by a railway dynamic analysis program, VAMPIRE. From the optimization results, it is verified that the global optimization method such as genetic algorithm is more suitable to wheel profile optimization than the local optimization of SQP (Sequential Quadratic Programming) in case of considering the lack of empirical knowledge for initial design value.

Hemimasticatory spasm is a very rare disorder of the trigeminal nerve characterized by paroxysmal involuntary contraction of the jaw-closing muscles. The mechanisms leading to hemimasticatory spasm are still unclear. Recently, injection of botulinum toxin has become the treatment of choice due to its excellent results. We report a case of a successful treatment of hemimasticatory spasm via microvascular decompression of the motor branch of the trigeminal nerve.

Dept. of Architectural Engineering, Sungkyunkwan University, Suwon 440-746, KoreaABSTRACT In this study, an estimation equation was proposed to predict the shear strength of RC interior beam-column con-nections. The proposed equation considered the effect of both truss and arch mechanisms, while the existing equations in the ACIand AIJ design codes consider only arch mechanism. In addition, the proposed equation estimates the shear strength of RC jointsby considering the contribution of the vertical and horizontal steel bars on the effective compressive strength of concrete. The shearstrength of RC joints calculated by the proposed equation was compared with the test results of 54 RC joints, which failed in shearbefore plastic hinges developed at the end of the adjacent beams. The comparison study showed that the proposed equation esti-mated the strength of the 54 specimens with a mean value of 1.14 and the coefficient of variation of 20%. The proposed equationprovides improved prediction compared to those obtained from the equations in the ACI and AIJ design codes.Keywords : beam-column joint, shear strength, J-failure, reinforcement steel, softening effect

We evaluated a video prompting procedure to teach adults with developmental disabilities to take a digital photograph and print it using a laptop computer and a printer. Participants were four men with developmental disabilities. Training was conducted at the participants' residential facility. During baseline, participants were told to take a photograph, but were given no other instruction. During intervention, participants received instruction using a video prompting procedure. Video prompting consisted of watching a clip of each step of the task analysis and then having the opportunity to imitate that step. Video prompting was evaluated using a multiple-probe across participants design. Following acquisition, video prompting was removed to assess maintenance at 2, 4 and 8 weeks and at 6 months. During naturalistic probes, participants had the opportunity to take a picture of their choice of flora, surroundings or persons. All four participants learned to take and print a digital photograph with the video prompting procedures. The skills generalized to novel situations and were maintained at each follow-up probe. These data suggest that video prompting may be an effective instructional strategy for teaching digital photography skills to adults with developmental disabilities.

Because most fatigue cracks in wheel and rail take place by rolling contact between wheel and rail in railway industry, it is critical to understand the rolling contact phenomena, especially for the three-dimensional situation. In this paper the steady-state and transient rolling contact problem of three-dimensional elastic bodies has been studied. The transient conditions were controlled by the applied relative slip. The variation of tangential traction and stick-slip region on rolling contact surface were obtained using the finite element method. The three-dimensional distribution of tangential traction and contact stresses on the contact surface are investigated. Results show that the distribution of tangential traction and contact stresses on the contact surface varies rapidly as a result of the variation of stick-slip region. The tangential traction is very close in form to Carter's distribution that contact region divided into stick and slip region. The contact stress at the leading edge is greater than at the trailing edge and the transient distance increases with small slip.