Design of dynamic plant model and model-based controller for a heat recovery system with a swirling flow incinerator

Cho, Jaeyoung,Kim, Yongtae,Song, Jeongwoo,Lee, Tae Kyung,Song, Han Ho Elsevier 2018 ENERGY Vol.147 No.-

<P><B>Abstract</B></P> <P>We developed a plant model and model-based controller for a heat recovery system with a swirling flow incinerator located in South Korea. First, a plant model was designed to understand the dynamic characteristics of the system. The system was divided into three parts: incinerator, boiler, and steam drum. Then, each part was modeled with a multi-zone, zero-dimensional modeling scheme. Consequently, we found that the plant model followed the dynamic behavior of the target system, particularly for the seven important variables: boiler inlet temperature, superheater inlet temperature, boiler outlet temperature, oxygen mole fraction, steam production rate, steam pressure, and steam temperature. Then, we designed a multi-input multi-output controller for the system with a nonlinear control model. In the controller design, input variables were selected as air flow rate, fuel supply rate and steam valve opening area; while output variables were oxygen mole fraction of exhaust gas, steam production rate and steam pressure. A nonlinear control model was constructed by reducing the plant model. Then a linear quadratic regulator was applied while evaluating control gain at each time step. Finally, we validated the controller on the plant model, which adequately suppressed the disturbance on fuel composition and adjusted the steam production rate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Plant model was built to simulate heat recovery system with a waste incinerator. </LI> <LI> Multi-input multi-output controller was designed for the system. </LI> <LI> The controller could efficiently suppress disturbance and adjusts load variation. </LI> </UL> </P>

Effect of the human papillomavirus vaccine on the risk of genital warts: a nationwide cohort study of Korean adolescent girls

Cho Jaeyoung,Kim Eun Mi,Kim Jihye,Shin Ju-Young,Kim Eui Hyeok,Park Jong Heon,Kwon Seunghyun Lewis,Kwon Geun-Yong,Shin Soon-Ae,Kim Jaiyong 한국역학회 2024 Epidemiology and Health Vol.46 No.-

OBJECTIVES The purpose of this study was to assess the effectiveness of human papillomavirus (HPV) vaccination administered to adolescent girls through Korea’s National Immunization Program. METHODS This retrospective cohort study included patients who were 12-13 years old, whether vaccinated or unvaccinated, between July 2016 and December 2017. The incidence of genital warts (GWs) was monitored through 2021. Time-stratified hazard ratios (HRs) were estimated, adjusting for birth year, socioeconomic status, and the level of urbanization of the region, and were presented with 95% confidence intervals (CIs). Data were sourced from the Immunization Registry Integration System, linked with the National Health Information Database. RESULTS The study included 332,062 adolescent girls, with an average follow-up period of approximately 4.6 years. Except for the first year, the HRs for the vaccinated group were lower than those for the unvaccinated group. The HRs for specific cut-off years were as follows: year 2, 0.62 (95% CI, 0.31 to 1.13); year 3, 0.58 (95% CI, 0.35 to 0.96); and year 4 and beyond, 0.39 (95% CI, 0.28 to 0.52). CONCLUSIONS Our findings indicate that HPV vaccination was associated with a reduction in the risk of GWs among adolescent girls. Notably, this reduction became significant as the incidence of GWs increased with age.

P-86 Long-Term Follow-up of Small Pulmonary Ground-Glass Nodules Stable for 3 Years: Implications of the Proper Follow-up Period and Risk Factors for Subsequent Growth

( Jaeyoung Cho ),( Eun Sun Kim ),( Se Joong Kim ),( Yeon Joo Lee ),( Jong Sun Park ),( Young-jae Cho ),( Ho Il Yoon ),( Jae Ho Lee ),( Choon-taek Lee ) 대한결핵 및 호흡기학회 2016 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.121 No.-

Introduction: How long persistent and stable ground-glass nodules (GGNs) should be followed is uncertain, although a minimum of 3 years is suggested. We evaluated a group of GGNs that had remained stable for an initial period of 3 years with the aim of determining the proportion of GGNs showing subsequent growth after the initial 3 years and identifying the clinical and radiologic factors associated with subsequent growth. Methods: We retrospectively analyzed patients who underwent further computed tomography (CT) after the initial 3-year follow-up period showing a persistent and stable GGN (at least 5 years of follow-up from the initial CT). Results: Between May 2003 and June 2015, 453 GGNs (438 pure GGNs and 15 part-solid GGNs) were found in 218 patients. Of the 218 patients, 14 had 15 GGNs showing subsequent growth after the initial 3 years during the median follow-up period of 6.4 years. For the person-based analysis, the frequency of subsequent growth of GGNs that had been stable during the initial 3 years was 6.7% (14 of 218). For the nodule-based analysis, the frequency was 3.3% (15 of 453). In a multivariate analysis, age 65 years or older (OR = 5.51, p = 0.012), history of lung cancer (OR = 6.44, p = 0.006), initial size 8 mm or larger (OR = 5.74, p = 0.008), presence of a solid component (OR = 16.58, p = 0.009), and air bronchogram (OR = 5.83, p = 0.015) were independent risk factors for subsequent GGN growth. Conclusions: For the individuals with GGNs having the aforementioned risk factors, the longer follow-up period is required to confirm subsequent GGN growth. 상기 초록은 J Thorac Oncol. 2016 Sep;11(9):1453-9에 출판된 논문의 초록임.

F-130 Treatment outcome of eosinophilic airway inflammation including non-asthmatic eosinophilic bronchitis

( Jaeyoung Cho ),( Sun Mi Choi ),( Jinwoo Lee ),( Young Sik Park ),( Sang-min Lee ),( Jae-joon Yim ),( Chul-gyu Yoo ),( Young Whan Kim ),( Sung Koo Han ),( Chang-hoon Lee ) 대한결핵 및 호흡기학회 2016 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.121 No.-

Background: The aim of this study is to elucidate the treatment outcome of eosinophilic airway inflammation in patients with chronic airway diseases including non-asthmatic eosinophilic bronchitis (NAEB). Methods: Patients with sputum eosinophilia confirmed between 2012 and 2015 in Seoul National University Hospital were enrolled. We evaluated the prognosis and predictors of acute exacerbation in NAEB patients and investigated predictors of the improvement of eosinophilic inflammation in chronic airway diseases such as NAEB, asthma, COPD, and asthma-COPD overlap syndrome (ACOS). Results: In total, 398 patients with sputum eosinophilia were enrolled. Of these patients, 152 (38.2%) with NAEB were identified. Among them, 10 (6.6%) experienced exacerbations requiring treatment of antibiotics or systemic steroids. Inhaled corticosteroids (ICSs) therapy did not affect the risk of exacerbation even in the analysis with propensity score (P = 0.942). Of 176 patients with chronic airway diseases 37 (21.0%) showed improvement of sputum eosinophilia at 1 year follow-up. Patients who had persistent airflow limitation and received ICS therapy for less than 75% of follow-up days were less likely to be improved in eosinophilic inflammation (aOR, 0.26; 95% CI, 0.09-0.77). Conclusions: About 6% of NAEB patients experienced exacerbations. Majority of patients with chronic airway diseases, especially COPD/ACOS patients, if they were not sufficiently treated with ICS, were less likely to achieve the improvement of eosinophilic inflammation.

Increased Patient Compliance with Silicone Gel Sheeting and Topical Silicone Gel for Hypertrophic Scar Improves Scar Outcomes

Cho Jaeyoung,Lee Jimin,박준 대한창상학회 2024 Journal of Wound Management and Research Vol.20 No.2

Background: Although silicone-based products are widely used for hypertrophic scar (HS) treatment, limited research exists on the correlation between patient compliance of silicone products and scar outcomes. This study aims to investigate whether continuous and consistent use of topical silicone gel (TSG) and silicone gel sheet (SGS) improves scar characteristics and whether patient compliance influences scar outcomes.Methods: A total of 79 patients with HS were randomized into either TSG (n=38) or SGS group (n=41) by an independent physician who had not seen the patients. Patient compliance was assessed based on application frequency and duration. Patients were divided into three subgroups according to compliance. Scar characteristics were evaluated using the Vancouver Scar Scale (VSS) and patient self-assessment via a visual analogue scale (VAS) for 6 months.Results: VSS pigmentation and scar height worsened in patients who applied silicone products for less than 3 days per week, especially in the TSG group. Patients who applied silicone products for more than 4 days per week showed significant improvements in all factors. Patients reported improvements in VAS scar height, pigmentation, and hardness as application time increased. Pain and itching improved regardless of application time.Conclusion: Continuous and consistent use of TSG and SGS improved HS outcomes. Applying silicone products more than 4 days in a week correlated with better scar characteristics, except pain and itching. Applying silicone products less than 3 days in a week is not recommended, as this may worsen scar height and pigmentation.

Mechanistic Insights into the C–H Bond Activation of Hydrocarbons by Chromium(IV) Oxo and Chromium(III) Superoxo Complexes

Cho, Kyung-Bin,Kang, Hyeona,Woo, Jaeyoung,Park, Young Jun,Seo, Mi Sook,Cho, Jaeheung,Nam, Wonwoo American Chemical Society 2014 Inorganic Chemistry Vol.53 No.1

<P>The mechanism of the C–H bond activation of hydrocarbons by a nonheme chromium(IV) oxo complex bearing an N-methylated tetraazamacrocyclic cyclam (TMC) ligand, [Cr<SUP>IV</SUP>(O)(TMC)(Cl)]<SUP>+</SUP> (<B>2</B>), has been investigated experimentally and theoretically. In experimental studies, reaction rates of <B>2</B> with substrates having weak C–H bonds were found to depend on the concentration and bond dissociation energies of the substrates. A large kinetic isotope effect value of 60 was determined in the oxidation of dihydroanthracene (DHA) and deuterated DHA by <B>2</B>. These results led us to propose that the C–H bond activation reaction occurs via a H-atom abstraction mechanism, in which H-atom abstraction of substrates by <B>2</B> is the rate-determining step. In addition, formation of a chromium(III) hydroxo complex, [Cr<SUP>III</SUP>(OH)(TMC)(Cl)]<SUP>+</SUP> (<B>3</B>), was observed as a decomposed product of <B>2</B> in the C–H bond activation reaction. The Cr<SUP>III</SUP>OH product was characterized unambiguously with various spectroscopic methods and X-ray crystallography. Density functional theory (DFT) calculations support the experimental observations that the C–H bond activation by <B>2</B> does not occur via the conventional H-atom-abstraction/oxygen-rebound mechanism and that <B>3</B> is the product formed in this C–H bond activation reaction. DFT calculations also propose that <B>2</B> may have some Cr<SUP>III</SUP>O<SUP>•–</SUP> character. The oxidizing power of <B>2</B> was then compared with that of a chromium(III) superoxo complex bearing the identical TMC ligand, [Cr<SUP>III</SUP>(O<SUB>2</SUB>)(TMC)(Cl)]<SUP>+</SUP> (<B>1</B>), in the C–H bond activation reaction. By performing reactions of <B>1</B> and <B>2</B> with substrates under identical conditions, we were able to demonstrate that the reactivity of <B>2</B> is slightly greater than that of <B>1</B>. DFT calculations again support this experimental observation, showing that the rate-limiting barrier for the reaction with <B>2</B> is slightly lower than that of <B>1</B>.</P><P>The C−H bond activation of hydrocarbons by nonheme chromium(IV) oxo and chromium(III) superhydroxo complexes, [Cr<SUP>IV</SUP>(O)(TMC)(Cl)]<SUP>+</SUP> and [Cr<SUP>III</SUP>(O<SUB>2</SUB>)(TMC)(Cl)]<SUP>+</SUP>, has been investigated experimentally and theoretically. The C−H bond activation by the chromium(IV) oxo complex does not occur via the conventional H-atom-abstraction/oxygen-rebound mechanism. The reactivity of the chromium(IV) oxo complex is slightly greater than that of the chromium(III) superoxo complex in the C−H bond activation reactions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-1/ic402831f/production/images/medium/ic-2013-02831f_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic402831f'>ACS Electronic Supporting Info</A></P>

A shop recommendation learning with Tensorflow.js

Jaeyoung Cho(조재영),Sangwon Lee(이상원),Tai Myoung Chung 한국컴퓨터정보학회 2019 한국컴퓨터정보학회 학술발표논문집 Vol.27 No.2

Through this research, the rating data of shops were analyzed. The model was designed for discrete multiple classification as to the corresponding data, and the following experiments were initiated to observe the learned machine. By comparing each benchmarks in the experiments, which contains different setting variables for the machine model, the hit ratio was measured which indicates how much it is matched with the expected label. By analyzing those results from each benchmarks, the model was redesigned one time during the research and the effects of each setting variables on this machine were clarified. Furthermore, the research result left the future works, which are related with how the learning could be improved and what should be designed in the further research.

Internationalization, Ownership Structure, and Performance

Jaeyoung Cho,Jangwoo Lee 한국경영학회 2016 한국경영학회 통합학술발표논문집 Vol.2016 No.8

This study explores the impact of the degree of internationalization (DOI) on the performance of small and medium-sized enterprises (SMEs), and the moderating impact of family ownership, foreign ownership, and domestic institutional ownership. An analysis of data from 232 Korean manufacturing SMEs during 2003–2013 reveals a U-shaped curvilinear relationship between DOI and performance. In addition, that link varies by owner type. Family ownership, foreign ownership, and domestic institutional ownership positively moderate the link between DOI and performance. However, both foreign ownership and domestic institutional ownership negatively moderate the joint impact of DOI and family ownership on performance. These findings indicate that distinguishing among dissimilar owner types is instrumental to improving our understanding of the nature of the DOI–performance relationship.

Bleeding complications in critically ill patients with liver cirrhosis

( Jaeyoung Cho ),( Sun Mi Choi ),( Su Jong Yu ),( Young Sik Park ),( Chang Hoon Lee ),( Sang Min Lee ),( Jae Joon Yim ),( Chul Gyu Yoo ),( Young Whan Kim ),( Sung Koo Han ),( Jinwoo Lee ) 대한내과학회 2016 The Korean Journal of Internal Medicine Vol.31 No.2

Background/Aims: Patients with liver cirrhosis (LC) are at risk for critical events leading to Intensive Care Unit (ICU) admission. Coagulopathy in cirrhotic patients is complex and can lead to bleeding as well as thrombosis. The aim of this study was to investigate bleeding complications in critically ill patients with LC admitted to a medical ICU (MICU). Methods: All adult patients admitted to our MICU with a diagnosis of LC from January 2006 to December 2012 were retrospectively assessed. Patients with major bleeding at the time of MICU admission were excluded from the analysis. Results: A total of 205 patients were included in the analysis. The median patient age was 62 years, and 69.3% of the patients were male. The most common reason for MICU admission was acute respiratory failure (45.4%), followed by sepsis (27.3%). Major bleeding occurred in 25 patients (12.2%). The gastrointestinal tract was the most common site of bleeding (64%), followed by the respiratory tract (20%). In a multivariate analysis, a low platelet count at MICU admission (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97 to 0.99) and sepsis (OR, 8.35; 95% CI, 1.04 to 67.05) were independent risk factors for major bleeding. The ICU fatality rate was significantly greater among patients with major bleeding (84.0% vs. 58.9%, respectively; p = 0.015). Conclusions: Major bleeding occurred in 12.2% of critically ill cirrhotic patients admitted to the MICU. A low platelet count at MICU admission and sepsis were associated with an increased risk of major bleeding during the MICU stay. Further study is needed to better understand hemostasis in critically ill patients with LC.

Sleep Apnea and Venous Thromboembolism: An Emerging Relationship

( Jaeyoung Cho ) 대한결핵 및 호흡기학회 2023 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.136 No.0