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휴먼형 로봇 손의 사물 조작 수행을 이용한 인간 행동 복제 강화학습 정책 최적화 방법 성능 평가
박나현 ( Na Hyeon Park ),오지헌 ( Ji Heon Oh ),류가현 ( Ga Hyun Ryu ),( Edwin Valarezo Añazco ),( Patricio Rivera Lopez ),원다슬 ( Da Seul Won ),정진균 ( Jin Gyun Jeong ),장윤정 ( Yun Jung Chang ),김태성 ( Tae-seong Kim ) 한국정보처리학회 2020 한국정보처리학회 학술대회논문집 Vol.27 No.2
로봇이 사람과 같이 다양하고 복잡한 사물 조작을 하기 위해서 휴먼형 로봇손의 사물 파지 작업이 필수적이다. 자유도 (Degree of Freedom, DoF)가 높은 휴먼형(anthropomorphic) 로봇손을 학습시키기 위하여 사람 데모(human demonstration)가 결합된 강화학습 최적화 방법이 제안되었다. 본 연구에서는 강화학습 최적화 방법에 사람 데모가 결합된 Demonstration Augmented Natural Policy Gradient (DA-NPG)와 NPG 의 성능 비교를 통하여 행동 복제의 효율성을 확인하고, DA-NPG, DA-Trust Region Policy Optimization (DA-TRPO), DA-Proximal Policy Optimization (DA-PPO)의 최적화 방법의 성능 평가를 위하여 6 종의 물체에 대한 휴먼형 로봇손의 사물 조작 작업을 수행한다. 그 결과, DA-NPG 와 NPG를 비교한 결과를 통해 휴먼형 로봇손의 사물 조작 강화학습에 행동 복제가 효율적임을 증명하였다. 또한, DA-NPG 는 DA-TRPO 와 유사한 성능을 보이면서 모든 물체에 대한 사물 파지에 성공하여 가장 안정적이었다. 반면, DA-TRPO 와 DA-PPO 는 사물 조작에 실패한 물체가 존재하여 불안정한 성능을 보였다. 본 연구에서 제안하는 방법은 향후 실제 휴먼형 로봇에 적용하여 휴먼형 로봇 손의 사물조작 지능 개발에 유용할 것으로 전망된다.
행동 복제 강화학습 및 딥러닝 사물 부분 검출 기술에 기반한 사람형 로봇손의 사물 조작
오지헌 ( Ji Heon Oh ),류가현 ( Ga Hyun Ryu ),박나현 ( Na Hyeon Park ),( Edwin Valarezo Añazco ),( Patricio Rivera Lopez ),원다슬 ( Da Seul Won ),정진균 ( Jin Gyun Jeong ),장윤정 ( Yun Jung Chang ),김태성 ( Tae-seong Kim ) 한국정보처리학회 2020 한국정보처리학회 학술대회논문집 Vol.27 No.2
최근 사람형(Anthropomorphic)로봇손의 사물조작 지능을 개발하기 위하여 행동복제(Behavior Cloning) Deep Reinforcement Learning(DRL) 연구가 진행중이다. 자유도(Degree of Freedom, DOF)가 높은 사람형 로봇손의 학습 문제점을 개선하기 위하여, 행동 복제를 통한 Human Demonstration Augmented(DA)강화 학습을 통하여 사람처럼 사물을 조작하는 지능을 학습시킬 수 있다. 그러나 사물 조작에 있어, 의미 있는 파지를 위해서는 사물의 특정 부위를 인식하고 파지하는 방법이 필수적이다. 본 연구에서는 딥러닝 YOLO 기술을 적용하여 사물의 특정 부위를 인식하고, DA-DRL 을 적용하여, 사물의 특정 부분을 파지하는 딥러닝 학습 기술을 제안하고, 2 종 사물(망치 및 칼)의 손잡이 부분을 인식하고 파지하여 검증한다. 본 연구에서 제안하는 학습방법은 사람과 상호작용하거나 도구를 용도에 맞게 사용해야하는 분야에서 유용할 것이다.
( Da-som Park ),( Jong-hyun Park ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.5
A risk analysis of Shiga toxin (Stx)-encoding bacteriophage was carried out by confirming the transduction phage to non-Stx-producing Escherichia coli (STEC) and subsequent expression of the Shiga toxin genes. The virulence factor stx1 was identified in five phages, and both stx1 and stx2 were found in four phages from a total of 19 phage isolates with seven non-O157 STEC strains. The four phages, designated as φNOEC41, φNOEC46, φNOEC47, and φNOEC49, belonged morphologically to the Myoviridae family. The stabilities of these phages to temperature, pH, ethanol, and NaClO were high with some variabilities among the phages. The infection of five non-STEC strains by nine Stx-encoding phages occurred at a rate of approximately 40%. Non-STEC strains were transduced by Stx-encoding phage to become lysogenic strains, and seven convertant strains had stx1 and/or stx2 genes. Only the stx1 gene was transferred to the receptor strains without any deletion. Gene expression of a convertant having both stx1 and stx2 genes was confirmed to be up to 32 times higher for Stx1 in 6% NaCl osmotic media and twice for Stx2 in 4% NaCl media, compared with expression in low-salt environments. Therefore, a new risk might arise from the transfer of pathogenic genes from Stx-encoding phages to otherwise harmless hosts. Without adequate sterilization of food exposed to various environments, there is a possibility that the toxicity of the phages might increase.
( Da Hyun Jung ),( Yong Chan Lee ),( Jie-hyun Kim ),( Hyunsoo Chung ),( Jun Chul Park ),( Sung Kwan Shin ),( Sang Kil Lee ),( Hyoung-il Kim ),( Woo Jin Hyung ),( Sung Hoon Noh ) 대한간학회 2017 Gut and Liver Vol.11 No.5
Background/Aims: Few studies have evaluated the effect of Helicobacter pylori infection on the prognosis of patients diagnosed with gastric cancer (GC) after curative surgery. We investigated the association between the H. pylori infection status and clinical outcome after surgery. Methods: We as-sessed the H. pylori status of 314 patients who underwent curative resection for GC. The H. pylori status was examined using a rapid urease test 2 months after resection. Patients were followed for 10 years after surgery. Results: An H. pylori infection was observed in 128 of 314 patients. The median follow-up period was 93.5 months. A Kaplan-Meier analysis indicated that patients with H. pylori had a higher cumula-tive survival rate than those who were negative for H. pylori. Patients with stage II cancer who tested negative for H. py-lori were associated with a poor outcome. In a multivariate analysis, H. pylori-negative status was a significant indepen-dent prognostic factor for poor overall survival. Conclusions: Having a negative H. pylori infection status seems to indicate poor prognosis for patients with GC who have undergone curative resection. Further prospective controlled studies are needed to evaluate the mechanism by which H. pylori af-fects GC patients after curative surgery in Korea. (Gut Liver 2017;11:635-641)
Park, Hae Eun,Lee, Seok-Young,Hyun, Sun-Hee,Kim, Da Yeon,Marriott, Philip J,Choi, Hyung-Kyoon Oxford University Press 2013 Journal of AOAC International Vol.96 No.6
<B>Abstract</B><P>Ginseng roots are an important herbal resource worldwide, and the adulteration of ginseng with age is recognized as a serious problem. It is therefore crucial to develop objective criteria or standard protocols for differentiating ginseng root samples according to their cultivation age. The reported study used GC/MS combined with multivariate statistical analysis with variable selection to obtain metabolic profiling and an optimal partial least squares-discriminant analysis (PLS-DA) model for the differentiation of ginseng according to cultivation age. Relative levels of various metabolites, such as amino acids, alcohols, fatty acids, organic acids, and sugars, were measured for various ginseng cultivation ages. Increasing cultivation age resulted in the production of higher levels of panaxynol and panaxydol, which are active polyacetylene compounds in ginseng. In addition, optimized PLS-DA models for the prediction of ginseng age were obtained by selecting variables based on a variable importance in the projection cut-off value of 1.3. Proline, glucaric acid, mannose, gluconic acid, glucuronic acid, myoinositol, panaxydol, and panaxynol are suggested as key and relevant compounds with which to differentiate the age of ginseng samples. The findings of this study suggest that GC/MS-based metabolic profiling can be used to differentiate ginseng samples according to cultivation age.</P>
GO-33 : Prognosis and Associated Factors in Neuroendocrine Cervical Carcinoma (NECC)
( Da Yong Lee ),( Maria Lee ),( Hee Seung Kim ),( Hyun Hoon Chung ),( Jae Weon Kim ),( Noh Hyun Park ),( Yong Sang Song ),( Sang Yoon Park ) 대한산부인과학회 2014 대한산부인과학회 학술대회 Vol.100 No.-
목적: To evaluate the clinical and pathologic factors associated with survival in patients with neuroendocrine cervical carcinoma (NECC).`방법: Among all patients with NECC diagnosed between 2000-2014 in Seoul national university hospital and national cancer center, data was`collected from hospital charts, scanned records and phone-calls. Kaplan-Meier and Cox regression methods were used for analyses.`결과: Total 61 patients were treated in NECC. Of them, 34 had Stages IB, 7 had Stages IIA, 9 had Stages IIB, 3 had Stages IIIB, and 8 had Stage`IV disease. A total of 60.7% underwent surgery, 95.1% received chemotherapy, 57.4% received radiation and 42.6% received concurrent chemoradiation`(CCRT). Women with early- stage (Stages I-IIA) disease had median survival rates of 45 months compared with 17 months in the advanced-`stage (Stages IIB-IVB) group. Patients with tumor size ≥2 cm had median survival rates of 67 months compared with 24 months with less`tumor size. In univariate analysis, advanced-stage (p=0.013), Tumor size ≥2 cm (p=0.002) were considered poor prognostic factors. In a multivariable`analysis, tumor size, and the FIGO stage of disease in the overall population remained as independent prognostic factor of survival. Of`all 39.3% of the patients had recurrence and 52.5% of early stage patients had recurrence. Total 54.1% of the patients had metastasis and 52.5%`of early stage patients had metastasis. Most frequent metastatic site was lung and liver.`결론: The FIGO stage and tumor size was found to be an independent prognostic factor of NECC. The role of postoperative CT or CCRT is`unclear. Clinical trials are needed. In cases of early stage disease, frequent recurrence and metastasis were observed, so close observation for`them is needed.
( Hyun-Joon Park ),( Da-Jung Kim ),( Kyoung-Im Cho ),( Jin-Wook Lee ),( Sun-Min Kim ),( Hyun-Su Kim ),( Jung Ho Heo ) 대한내과학회 2015 대한내과학회 추계학술대회 Vol.2015 No.1
Background: Epicardial fat tissue has unique endocrine and paracrine functions that affect the cardiac autonomic system. Heart rate recovery (HRR) is a simple non-invasive measurement that assesses autonomic nervous system dysfunction. We aimed to investigate the association between epicardial fat thickness (EFT) and HRR in patients with hypertension according to circadian blood pressure (BP) variation. Methods: A total of 358 consecutive patients who underwent both 24-hour ambulatory BP monitoring (ABPM) and a treadmill test were enrolled. Echocardiographic EFT and HRR, defined as peak heart rate minus heart rate after a 1-minute recovery time, were measured. Patients were classified according to the ABPM; 147 patients with hypertension with a dipping pattern at night (dippers), 140 patients with hypertension with a non-dipping pattern at night (non-dippers) and 71 normotensive controls. Results: EFT was significantly higher in hypertensive patients, especially in the non-dipper group, compared to the controls (non-dippers, 7.5 ± 2.9 mm; dippers, 6.6 ± 1.6 mm; controls, 5.5 ± 2.1 mm; p<0.001). HRR was significantly lower in both hypertensive groups as compared to the control group and was the lowest in the non-dipper group (non-dipper, 26.6 ± 18.6; dipper, 29.5 ± 21.5; control, 71.4 ± 19.8; p<0.001). EFT was significantly correlated with age, body mass index, 24-hour mean systolic BP and 24 hours mean BP variability, whereas exercise duration, metabolic equivalents (METs) and HRR were inversely correlated with EFT. Furthermore, EFT>6.7 mm was associated with a blunted HRR with 76% sensitivity and 61% specificity (ROC area under curve: 0.71, 95% confidence interval, CI=0.65-0.76, p<0.001). In a multivariate analysis, EFT (odds ratio, OR =3.53, 95% CI=1.20-10.37, p=0.022) and 24-hour mean BP variability (OR=1.09, 95% CI=1.03-1.16, p=0.005) were independent predictors of a blunted HRR defined as HRR ≤12 beats (n=63) in patients with hypertension. Conclusions: EFT and circadian BP variability were independent predictors of blunted HRR in patients with hypertension, which suggests a link between epicardial fat and autonomic dysregulation in hypertension.
( Hyun Ae Jung ),( Young Eun Ha ),( Da Min Kim ),( Ji Hyun Park ),( Cheol In Kang ),( Doo Ryeon Chung ),( Seung Woo Park ),( Ki Ik Sung ),( Jae Hoon Song ),( Kyong Ran Peck ) 대한내과학회 2014 The Korean Journal of Internal Medicine Vol.29 No.3
Klebsiella species are common pathogensthat cause community-onsetand hospital-acquired pneumonia,intra-abdominal infections, andbloodstream infections. Infective endocarditisdue to Klebsiella species israre, accounting for less than 1% ofcases, and is frequently accompaniedby complications and a high in-hospitalmortality rate [1]. Moreover, withthe emergence of extended-spectrumb-lactamase (ESBL)-producing Enterobacteriaceae,endocarditis due toESBL-producing Klebsiella pneumonia(ESBL-KP) is of concern due to thelimited treatment options and notoriouslyhigh morbidity and mortality. Hospitalization is a significant riskfactor for bloodstream infections dueto ESBL-producing Enterobacteriaceae,but no cases of health-care-associatednative valve endocarditis causedby ESBL-KP have been reported. Here,we report a case of health-care-associatedinfective endocarditis due toESBL-KP with multiple metastaticinfectious complications, and discussthe optimal treatment strategies.