A New Incremental Learning Algorithm with Probabilistic Weights Using Extended Data Expression

Yang, Kwangmo,Kolesnikova, Anastasiya,Lee, Won Don The Korea Institute of Information and Commucation 2013 Journal of information and communication convergen Vol.11 No.4

New incremental learning algorithm using extended data expression, based on probabilistic compounding, is presented in this paper. Incremental learning algorithm generates an ensemble of weak classifiers and compounds these classifiers to a strong classifier, using a weighted majority voting, to improve classification performance. We introduce new probabilistic weighted majority voting founded on extended data expression. In this case class distribution of the output is used to compound classifiers. UChoo, a decision tree classifier for extended data expression, is used as a base classifier, as it allows obtaining extended output expression that defines class distribution of the output. Extended data expression and UChoo classifier are powerful techniques in classification and rule refinement problem. In this paper extended data expression is applied to obtain probabilistic results with probabilistic majority voting. To show performance advantages, new algorithm is compared with Learn++, an incremental ensemble-based algorithm.

New Facilities for Radiation Research in DIRAMS

Kwangmo Yang 한국실험동물학회 2010 한국실험동물학회 학술발표대회 논문집 Vol.2010 No.8

Clinical utilization of radiation therapy in Korea between 2017 and 2019

Eunji Kim(Eunji Kim),Won Il Jang(Won Il Jang),Kwangmo Yang(Kwangmo Yang),Mi-Sook Kim(Mi-Sook Kim),Hyung Jun Yoo(Hyung Jun Yoo),Eun Kyung Paik(Eun Kyung Paik),Heejin Kim(Heejin Kim),Jaesun Yoon(Jaesun 대한방사선종양학회 2022 Radiation Oncology Journal Vol.40 No.4

Purpose: This study aimed to evaluate the clinical infrastructure and utilization of radiotherapy (RT) services in Korea between 2017 and 2019. Materials and Methods: We extracted the data of patients who underwent RT between 2017 and 2019 from the Health Insurance Review and Assessment Service. We further analyzed this data according to the diagnosis and treatment modalities of patients diagnosed with International Classification of Disease 10 (ICD-10) diagnostic codes C00–C97 and D00–D48. In addition, we collected statistics on RT facilities in Korea using a nationwide survey. Results: The total number of patients who received RT in 2017, 2018, and 2019 were 77,901, 81,849, and 87,460, respectively. The number of patients diagnosed with ICD 10 C- and D-codes in 2019 was 86,339, of whom 39,467 were men and 46,872 women. The rate of utilization of RT among cancer patients was 30.4% in 2017 and 2018 and 30.9% in 2019. In 2019, the most common types of cancers treated with RT were breast, lung, prostate, colorectal, and liver cancers. Regarding the RT infrastructure in Korea, there were 95 radiation oncology centers, 237 megavoltage (MV) teletherapy units, 35 brachytherapy units, and two proton accelerators in 2019. There were 4.5 MV teletherapy machines per million. Conclusion: The number of patients treated with RT has increased consistently from 2017 to 2019. As the number of patients with cancer increases, it is expected that the RT infrastructure will be further expanded in Korea.

In Vitro Genotoxicity Assessment of a Novel Resveratrol Analogue, HS-1793

Jeong, Min Ho,Yang, Kwangmo,Lee, Chang Geun,Jeong, Dong Hyeok,Park, You Soo,Choi, Yoo Jin,Kim, Joong Sun,Oh, Su Jung,Jeong, Soo Kyung,Jo, Wol Soon Korean Society of ToxicologyKorea Environmental Mu 2014 Toxicological Research Vol.30 No.3

Resveratrol has received considerable attention as a polyphenol with various biological effects such as anti-inflammatory, anti-oxidant, anti-mutagenic, anti-carcinogenic, and cardioprotective properties. As part of the overall safety assessment of HS-1793, a novel resveratrol analogue free from the restriction of metabolic instability and the high dose requirement of resveratrol, we assessed genotoxicity in three in vitro assays: a bacterial mutation assay, a comet assay, and a chromosomal aberration assay. In the bacterial reverse mutation assay, HS-1793 did not increase revertant colony numbers in S. typhimurium strains (TA98, TA100, TA1535 and TA1537) or an E. coli strain (WP2 uvrA) regardless of metabolic activation. HS-1793 showed no evidence of genotoxic activity such as DNA damage on L5178Y $Tk^{+/-}$ mouse lymphoma cells with or without the S9 mix in the in vitro comet assay. No statistically significant differences in the incidence of chromosomal aberrations following HS-1793 treatment was observed on Chinese hamster lung cells exposed with or without the S9 mix. These results provide additional evidence that HS-1793 is non-genotoxic at the dose tested in three standard tests and further supports the generally recognized as safe determination of HS-1793 during early drug development.

In Vitro Genotoxicity Assessment of a Novel Resveratrol Analogue, HS-1793

Min Ho Jeong,Kwangmo Yang,Chang Geun Lee,Dong Hyeok Jeong,You Soo Park,Yoo Jin Choi,Joong Sun Kim,Su Jung Oh,Soo Kyung Jeong,Wol Soon Jo 한국독성학회 2014 Toxicological Research Vol.30 No.3

Resveratrol has received considerable attention as a polyphenol with various biological effects such as anti-inflammatory, anti-oxidant, anti-mutagenic, anti-carcinogenic, and cardioprotective properties. As part of the overall safety assessment of HS-1793, a novel resveratrol analogue free from the restriction of metabolic instability and the high dose requirement of resveratrol, we assessed genotoxicity in three in vitro assays: a bacterial mutation assay, a comet assay, and a chromosomal aberration assay. In the bacterial reverse mutation assay, HS-1793 did not increase revertant colony numbers in S. typhimurium strains (TA98, TA100, TA1535 and TA1537) or an E. coli strain (WP2 uvrA) regardless of metabolic activation. HS-1793 showed no evidence of genotoxic activity such as DNA damage on L5178Y Tk<SUP>+/?</SUP> mouse lymphoma cells with or without the S9 mix in the in vitro comet assay. No statistically significant differences in the incidence of chromosomal aberrations following HS-1793 treatment was observed on Chinese hamster lung cells exposed with or without the S9 mix. These results provide additional evidence that HS-1793 is non-genotoxic at the dose tested in three standard tests and further supports the generally recognized as safe determination of HS-1793 during early drug development.

Association of preoperative blood glucose level with delirium after non-cardiac surgery in diabetic patients

Park Soo Jung,Oh Ah Ran,이종환,Yang Kwangmo,박정찬 대한마취통증의학회 2024 Korean Journal of Anesthesiology Vol.77 No.2

Background: Hyperglycemia has shown a negative association with cognitive dysfunction. We analyzed patients with high preoperative blood glucose level and hemoglobin A1c (HbA1c) level to determine the prevalence of postoperative delirium.Methods: We reviewed a database of 23,532 patients with diabetes who underwent non-cardiac surgery. Acute hyperglycemia was defined as fasting blood glucose > 140 mg/dl or random glucose > 180 mg/dl within 24 h before surgery. Chronic hyperglycemia was defined as HbA1c level above 6.5% within three months before surgery. The incidence of delirium was compared according to the presence of acute and chronic hyperglycemia.Results: Of the 23,532 diabetic patients, 21,585 had available preoperative blood glucose level within 24 h before surgery, and 18,452 patients reported levels indicating acute hyperglycemia. Of the 8,927 patients with available HbA1c level within three months before surgery, 5,522 had levels indicating chronic hyperglycemia. After adjustment with inverse probability weighting, acute hyperglycemia was related to higher incidence of delirium (hazard ratio: 1.33, 95% CI [1.10,1.62], P = 0.004 for delirium) compared with controls without acute hyperglycemia. On the other hand, chronic hyperglycemia did not correlate with postoperative delirium.Conclusions: Preoperative acute hyperglycemia was associated with postoperative delirium, whereas chronic hyperglycemia was not significantly associated with postoperative delirium. Irrespective of chronic hyperglycemia, acute glycemic control in surgical patients could be crucial for preventing postoperative delirium.

Perioperative adverse cardiac events and mortality after non-cardiac surgery: a multicenter study

Choi Byungjin,Oh Ah Ran,박정찬,이종환,Yang Kwangmo,Lee Dong Yun,Rhee Sang Youl,Kang Sang Soo,Lee Seung Do,Lee Sun Hack,Jeong Chang Won,Park Bumhee,설수빈,Park Rae Woong,Lee Seunghwa 대한마취통증의학회 2024 Korean Journal of Anesthesiology Vol.77 No.1

Background: Perioperative adverse cardiac events (PACE), a composite of myocardial infarction, coronary revascularization, congestive heart failure, arrhythmic attack, acute pulmonary embolism, cardiac arrest, and stroke during 30-day postoperative period, is associated with long-term mortality, but with limited clinical evidence. We compared long-term mortality with PACE using data from nationwide multicenter electronic health records.Methods: Data from 7 hospitals, converted to Observational Medical Outcomes Partnership Common Data Model, were used. We extracted records of 277,787 adult patients over 18 years old undergoing non-cardiac surgery for the first time at the hospital and had medical records for more than 180 days before surgery. We performed propensity score matching and then an aggregated meta‑analysis.Results: After 1:4 propensity score matching, 7,970 patients with PACE and 28,807 patients without PACE were matched. The meta‑analysis showed that PACE was associated with higher one-year mortality risk (hazard ratio [HR]: 1.33, 95% CI [1.10, 1.60], P = 0.005) and higher three-year mortality (HR: 1.18, 95% CI [1.01, 1.38], P = 0.038). In subgroup analysis, the risk of one-year mortality by PACE became greater with higher-risk surgical procedures (HR: 1.20, 95% CI [1.04, 1.39], P = 0.020 for low-risk surgery; HR: 1.69, 95% CI [1.45, 1.96], P < 0.001 for intermediate-risk; and HR: 2.38, 95% CI [1.47, 3.86], P = 0.034 for high-risk).Conclusions: A nationwide multicenter study showed that PACE was significantly associated with increased one-year mortality. This association was stronger in high-risk surgery, older, male, and chronic kidney disease subgroups. Further studies to improve mortality associated with PACE are needed.

Association between inflammation-based prognostic markers and mortality of non-cardiac surgery

Oh Ah Ran,박정찬,이종환,Yang Kwangmo,Ahn Joong Hyun,Lee Seung-Hwa,이상민 대한마취통증의학회 2023 Korean Journal of Anesthesiology Vol.76 No.6

Background: To evaluate the association between inflammation and nutrition-based biomarkers and postoperative outcomes after non-cardiac surgery.Methods: Between January 2011 and June 2019, a total of 102,052 patients undergoing non-cardiac surgery were evaluated, with C-reactive protein (CRP), albumin, and complete blood count (CBC) measured within six months before surgery. We assessed their CRP-to-albumin ratio (CAR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and modified Glasgow Prognostic Score (mGPS). We determined the best cut-off values by using the receiver operating characteristic (ROC) curves. Patients were divided into high and low groups according to the estimated threshold, and we compared the one-year mortality.Results: The one-year mortality of the entire sample was 4.2%. ROC analysis revealed areas under the curve of 0.796, 0.743, 0.670, and 0.708 for CAR, NLR, PLR, and mGPS, respectively. According to the estimated threshold, high CAR, NLR, PLR, and mGPS were associated with increased one-year mortality (1.7% vs. 11.7%, hazard ratio [HR]: 2.38, 95% CI [2.05, 2.76], P < 0.001 for CAR; 2.2% vs. 10.3%, HR: 1.81, 95% CI [1.62, 2.03], P < 0.001 for NLR; 2.6% vs. 10.5%, HR: 1.86, 95% CI [1.73, 2.01], P < 0.001 for PLR; and 2.3% vs. 16.3%, HR: 2.37, 95% CI [2.07, 2.72], P < 0.001 for mGPS).Conclusions: Preoperative CAR, NRL, PLR, and mGPS were associated with postoperative mortality. Our findings may be helpful in predicting mortality after non-cardiac surgery.

Accuracy of Cloud-Based Speech Recognition Open Application Programming Interface for Medical Terms of Korean

Seung-Hwa Lee,Jungchan Park,Kwangmo Yang,Jeongwon Min,Jinwook Choi 대한의학회 2022 Journal of Korean medical science Vol.37 No.18

Background: There are limited data on the accuracy of cloud-based speech recognition (SR) open application programming interfaces (APIs) for medical terminology. This study aimed to evaluate the medical term recognition accuracy of current available cloud-based SR open APIs in Korean. Methods: We analyzed the SR accuracy of currently available cloud-based SR open APIs using real doctor–patient conversation recordings collected from an outpatient clinic at a large tertiary medical center in Korea. For each original and SR transcription, we analyzed the accuracy rate of each cloud-based SR open API (i.e., the number of medical terms in the SR transcription per number of medical terms in the original transcription). Results: A total of 112 doctor–patient conversation recordings were converted with three cloud-based SR open APIs (Naver Clova SR from Naver Corporation; Google Speech-toText from Alphabet Inc.; and Amazon Transcribe from Amazon), and each transcription was compared. Naver Clova SR (75.1%) showed the highest accuracy with the recognition of medical terms compared to the other open APIs (Google Speech-to-Text, 50.9%, P < 0.001; Amazon Transcribe, 57.9%, P < 0.001), and Amazon Transcribe demonstrated higher recognition accuracy compared to Google Speech-to-Text (P < 0.001). In the sub-analysis, Naver Clova SR showed the highest accuracy in all areas according to word classes, but the accuracy of words longer than five characters showed no statistical differences (Naver Clova SR, 52.6%; Google Speech-to-Text, 56.3%; Amazon Transcribe, 36.6%). Conclusion: Among three current cloud-based SR open APIs, Naver Clova SR which manufactured by Korean company showed highest accuracy of medical terms in Korean, compared to Google Speech-to-Text and Amazon Transcribe. Although limitations are existing in the recognition of medical terminology, there is a lot of rooms for improvement of this promising technology by combining strengths of each SR engines.

Synergistic enhancement of NK cell-mediated cytotoxicity by combination of histone deacetylase inhibitor and ionizing radiation

Son, Cheol-Hun,Keum, Jin-Hee,Yang, Kwangmo,Nam, Jiho,Kim, Mi-Ju,Kim, Sun-Hee,Kang, Chi-Dug,Oh, Sae-Ock,Kim, Chi-Dae,Park, You-Soo,Bae, Jaeho BioMed Central 2014 Radiation oncology Vol.9 No.-

<P><B>Background</B></P><P>The overexpression of histone deacetylase (HDAC) and a subsequent decrease in the acetylation levels of nuclear histones are frequently observed in cancer cells. Generally it was accepted that the deacetylation of histones suppressed expression of the attached genes. Therefore, it has been suggested that HDAC might contribute to the survival of cancer cells by altering the NKG2D ligands transcripts. By the way, the translational regulation of NKG2D ligands remaines unclear in cancer cells. It appears the modulation of this unclear mechanism could enhance NKG2D ligand expressions and the susceptibility of cancer cells to NK cells. Previously, it was reported that irradiation can increase the surface expressions of NKG2D ligands on several cancer cell types without increasing the levels of NKG2D ligand transcripts via ataxia telangiectasia mutated and ataxia telangiectasia and Rad3 related (ATM-ATR) pathway, and suggested that radiation therapy might be used to increase the translation of NKG2D ligands.</P><P><B>Methods</B></P><P>Two NSCLC cell lines, that is, A549 and NCI-H23 cells, were used to investigate the combined effects of ionizing radiation and HDAC inhibitors on the expressions of five NKG2D ligands. The mRNA expressions of the NKG2D ligands were quantitated by multiplex reverse transcription-PCR. Surface protein expressions were measured by flow cytometry, and the susceptibilities of cancer cells to NK cells were assayed by time-resolved fluorometry using the DELFIA® EuTDA cytotoxicity kit and by flow cytometry.</P><P><B>Results</B></P><P>The expressions of NKG2D ligands were found to be regulated at the transcription and translation levels. Ionizing radiation and HDAC inhibitors in combination synergistically increased the expressions of NKG2D ligands. Furthermore, treatment with ATM-ATR inhibitors efficiently blocked the increased translations of NKG2D ligands induced by ionizing radiation but did not block the increased ligand translations induced by HDAC inhibitors. The study confirms that increased NKG2D ligand levels by ionizing radiation and HDAC inhibitors could synergistically enhance the susceptibilities of cancer cells to NK-92 cells.</P><P><B>Conclusions</B></P><P>This study suggests that the expressions of NKG2D ligands are regulated in a complex manner at the multilevel of gene expression, and that their expressions can be induced by combinatorial treatments in lung cancer cells.</P>