Beam search를 이용한 계층 RNN 챗봇의 성능향상

김형준(Hyunggin Kim),이창환(Changhwan Lee) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.12

MAF(Multimedia Application File Format) 기반 멀티미디어 검색 시스템의 설계 및 구현

강영모(Youngmo Gang),박주현(Joohyoun Park),방형진(Hyunggin Bang),낭종호(Jongho Nang),김형철(Hyungchul Kim) 한국정보과학회 2006 정보과학회논문지 : 시스템 및 이론 Vol.33 No.9

최근 MPEG-A(ISO/IEC 23000)에서는 MAF(Multimedia Application File Format)[1]라는 새로운 멀티미디어 파일 포맷을 제안하고 있다. MAF 파일포맷은 기존의 MPEG 압축 규격을 갖는 미디어 파일에 더해, 미디어 내용 정보를 기술하는 메타데이타를 MPEG-7을 사용하여 하나의 시스템 포맷 내에 포함할 수 있도록 해준다. 하지만 현재로서는 이러한 표준을 구현한 실제 시스템이 없기 때문에, 응용 측면에서 MAF가 얼마나 유용한지 검증하기 어렵다는 문제점을 가지고 있다. 본 논문에서는 PC와 모바일 단말기상에서 MPEG-A 표준을 기반으로 한 멀티미디어 검색 시스템을 설계 및 구현한다. 또한 MPEG-A에서는 아직 동영상에 관련된 메타데이타에 대해서는 제안된 바가 없기 때문에 MPEG-7 MDS(Multimedia Description Scheme)[2]와 TV-Anytime[3]을 기반으로 모바일 환경에서도 저작 및 사용하기 편리한 메타데이타들을 설계한다. 전체 시스템을 설계하기 위해서 MAF 검색 시스템이 가져야 할 5가지 요구사항인 이식성, 확장성, 호환성, 적응성, 효율성을 정의하고 이러한 요구사항을 바탕으로 하여 MAF 검색 시스템의 전체 구조를 응용 계층, 미들웨어 계층, 플랫폼 계층으로 설계한다. 제안하는 검색시스템은 MAF 형식의 멀티미디어 데이타를 저작, 재생, 검색할 수 있는 클라이언트 파트와, 대용량의 MAF 형식의 멀티미디어 파일과 MAF 파일로부터 추출한 MPEG-7 형태의 메타데이타를 저장, 관리할 수 있는 서버 파트로 구성된다. 그리고 설계한 MAF 검색 시스템의 유용성을 검증하기 위하여, PC에서는 MS 윈도우 플랫폼 그리고 모바일 단말기에서는 WIPI 플랫폼 상에서 클라이언트 시스템을 구현하고 시스템 요구사항들을 모두 만족하는지 여부를 확인한다. 제안하는 검색 시스템은 MPEG-A 표준을 검증하고 그 유용성을 확인하기 위해 사용될 수 있다. Recently, ISO/IEC 23000 (also known as “MPEG-A”) has proposed a new file format called "MAF(Multimedia Application File Format)[1]" which provides a capability of integrating/storing the widely-used compression standards for audio and video and the metadata in MPEG-7 form into a single file format. However, it is still very hard to verify the usefulness of MPEG-A in the real applications because there is still no real system that fully implements this standard. In this thesis, a design and implementation of a multimedia retrieval system based on MPEG-A standard on PC and mobile device is presented. Furthermore, an extension of MPEG-A for describing the metadata for video is also proposed. It is selected and defined as a subset of MPEG-7 MDS[4] and TV-anytime[5] for video that is useful and manageable in the mobile environments. In order to design the multimedia retrieval system based on MPEG-A, we define the system requirements in terms of portability, extensibility, compatibility, adaptability, efficiency. Based on these requirements, we design the system which composed of 3 layers: Application Layer, Middleware Layer, Platform Layer. The proposed system consists of two sub-parts, client-part and server-part. The client-part consists of MAF authoring tool, MAF player tool and MAF searching tool which allow users to create, play and search the MAF files, respectively. The server-part is composed of modules to store and manage the MAF files and metadata extracted from MAF files. We show the usefulness of the proposed system by implementing the client system both on MS-Windows platform on desk-top computer and WIPI platform on mobile phone, and validate whether it to satisfy all the system requirements. The proposed system can be used to verify the specification in the MPEG-A, and to proves the usefulness of MPEG-A in the real application.

Serum milk fat globule-EGF factor 8 protein as a potential biomarker for metabolic syndrome

( Han Ah Lee ),( Jihwan Lim ),( Hyung Joon Joo ),( Young-sun Lee ),( Young Kul Jung ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Yoon Tae Jeen ),( Jong Eun Yeon ),( Do-sun Lim ),( Kwan Soo B 대한간학회 2021 Clinical and Molecular Hepatology(대한간학회지) Vol.27 No.3

Background/Aims: Useful biomarkers for metabolic syndrome have been insufficient. We investigated the performance of serum milk fat globule-EGF factor-8 (MFG-E8), the key mediator of inflammatory pathway, in diagnosis of metabolic syndrome. Methods: Subjects aged between 30 and 64 years were prospectively enrolled in the Seoul Metabolic Syndrome cohort. Serum MFG-E8 levels were measured at baseline. Results: A total of 556 subjects were included, comprising 279 women (50.2%) and 277 men (49.8%). Metabolic syndrome was diagnosed in 236 subjects (42.4%), and the mean MFG-E8 level of subjects with metabolic syndrome was significantly higher than that of subjects without metabolic syndrome (P<0.001). MFG-E8 level was significantly correlated with all metabolic syndrome components and pulse wave velocity (all P<0.05). Subjects were categorized into two groups according to the best MFG-E8 cut-off value as follows: group 1, MFG-E8 level <4,745.1 pg/mL (n=401, 72.1%); and group 2, MFG-E8 level ≥4,745.1 (n=155, 27.9%). At baseline, metabolic syndrome in group 2 was significantly more prevalent than in group 1 (63.9% vs. 34.2%, P<0.001). During median follow-up of 17 months, metabolic syndrome developed in 122 (38.1%) subjects among 320 subjects without it at baseline. The incidence of metabolic syndrome in group 2 was significantly higher than that in group 1 (55.4% vs. 34.5%, P=0.003). On multivariate analysis, MFG-E8 level ≥4,745.1 pg/mL was an independent predictor for diagnosis and development of metabolic syndrome after adjusting other factors (all P<0.05). Conclusions: Serum MFG-E8 level is a potent biomarker for the screening and prediction of metabolic syndrome. (Clin Mol Hepatol 2021;27:463-473)

Risk Factors for Dropout from the Liver Transplant Waiting List under Locoregional Treatment

( Han Ah Lee ),( Yeon Seok Seo ),( Tae Hyung Kim ),( Sang Jun Suh ),( Young Kul Jung ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Jong Eun Yeon ),( Kwan Soo Byun ),( Soon Ho Um ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: The current liver allocation system has changed its policy to delay granting Model for End Stage Liver Disease (MELD) exception points to all HCC patients for 6 months. However, it may not be appropriate due to possibility of dropout within 6 months in high risk hepatocellular carcinoma (HCC) patients. Methods: All patients who were diagnosed as UNOS stage 1 or 2 of HCC at three hospitals of the Korea University (Anam, Guro, and Ansan) between January 2004 and December 2012 were included. Patients who only received locoregional treatment were included. Results: A total of 586 patients were included. Age was 59.9 ± 10.3 years and 409 patients (69.8%) were men. MELD score was 9.9 ± 3.0. Number of tumors was 1.3 ±0.6 and size of the maximum nodule was 2.0 ± 0.9 cm. Serum AFP level was 1.3 ± 0.8 log10 ng/mL. Among all included patients, 337 (57.5%) and 249 (42.5%) patients were treated with RFA and TACE, respectively. CR was achieved in 481 patients (82.2%) with first-line treatment. Within 6 months, 24 patients (4.1%) reached estimated dropout (eDO) by downstaging approach. Size of the maximum nodule (ł4 cm) was the only independent factor for eDO within 6 months. Extrahepatic progression developed in 16 patients (2.7%) within 1 year. Size of the maximum nodule (ł4 cm) and serum alpha-fetoprotein level (>100 ng/mL) were independent predictors for extrahpeatic progression within 1 year. Conclusions: HCC progressed to above Milan criteria during 6 months in 4.1% of patients with UNOS stage 1 or 2. Advantage points might be needed for patients with high risk of eDO (maximum size ł4 cm) to allow them to compete fairly. However, caution is needed in the patients of high risk of early progression with maximum size ł4 cm and high serum alpha-fetoprotein level (>100 ng/mL).

Law Index as an Accurate Indicator for the Initiation of Antiviral Treatment in Patients with Chronic Hepatitis B

Jae Min Lee,Yeon Seok Seo,Chang Ho Jung,Tae Hyung Kim,Sun Young Yim,Jin Dong Kim,Hyunggin An,Soon Ho Um,Ho Sang Ryu 한국간담췌외과학회 2014 한국간담췌외과학회 학술대회지 Vol.2014 No.4

Hepatitis B surface antigen titer is a good indicator of durable viral response after entecavir off-treatment for chronic hepatitis B

( Han Ah Lee ),( Yeon Seok Seo ),( Seung Woon Park ),( Sang Jung Park ),( Tae Hyung Kim ),( Sang Jun Suh ),( Young Kul Jung ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Jong Eun Yeon ),( Kwa 대한간학회 2016 Clinical and Molecular Hepatology(대한간학회지) Vol.22 No.3

Background/Aims: Clear indicators for stopping antiviral therapy in chronic hepatitis B (CHB) patients are not yet available. Since the level of hepatitis B surface antigen (HBsAg) is correlated with covalently closed circular DNA, the HBsAg titer might be a good indicator of the off-treatment response. This study aimed to determine the relationship between the HBsAg titer and the entecavir (ETV) off-treatment response. Methods: This study analyzed 44 consecutive CHB patients (age, 44.6±11.4 years, mean±SD; men, 63.6%; positive hepatitis B envelope antigen (HBeAg) at baseline, 56.8%; HBV DNA level, 6.8±1.3 log10 IU/mL) treated with ETV for a sufficient duration and in whom treatment was discontinued after HBsAg levels were measured. A virological relapse was defined as an increase in serum HBV DNA level of >2000 IU/mL, and a clinical relapse was defined as a virological relapse with a biochemical flare, defined as an increase in the serum alanine aminotransferase level of >2 × upper limit of normal. Results: After stopping ETV, virological relapse and clinical relapse were observed in 32 and 24 patients, respectively, during 20.8±19.9 months of follow-up. The cumulative incidence rates of virological relapse were 36.2% and 66.2%, respectively, at 6 and 12 months, and those of clinical relapse were 14.3% and 42.3%. The off-treatment HBsAg level was an independent factor associated with clinical relapse (hazard ratio, 2.251; 95% confidence interval, 1.076-4.706; P=0.031). When patients were grouped according to off-treatment HBsAg levels, clinical relapse did not occur in patients with an off-treatment HBsAg level of ≤2 log10 IU/mL (n=5), while the incidence rates of clinical relapse at 12 months after off-treatment were 28.4% and 55.7% in patients with off-treatment HBsAg levels of >2 and ≤3 log10 IU/mL (n=11) and >3 log₁₀ IU/mL (n=28), respectively. Conclusions: The off-treatment HBsAg level is closely related to clinical relapse after treatment cessation. A serum HBsAg level of <2 log₁₀ IU/mL is an excellent predictor of a sustained off-treatment response in CHB patients who have received ETV for a sufficient duration. (Clin Mol Hepatol 2016;22:382-389)

Prediction of Acute Kidney Injury and Mortality in Pa-tients with Decompensated Cirrhosis with Serum Cysta-tin C and Urine N-Acetyl-β-D-Glucosaminidase

( Tae Hyung Kim ),( Yeon Seok Seo ),( Yoo Ra Lee ),( Han Ah Lee ),( Sun Young Yim ),( Young Sun Lee ),( Sang Jun Suh ),( Young Kul Jung ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Jong Eun 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Acute kidney injury (AKI) is a common complication in cirrhotic patients, and also associated with increased mortality and development of complications including variceal bleeding, spontaneous bacterial peritonitis and encephalopathy. Currently, there are limitations to use serum creatinine to distinguish patients at high risk for AKI in patients with cirrhosis. We tried to elicit the association between levels of renal biomarkers including serum cystatin C and urine N-acetyl-β-D-glucosaminidase (NAG) and the prognosis of patients with decompensated cirrhosis. Methods: In 84 hospitalized patients with decompensated cirrhosis and without AKI at baseline, we identified serum creatinine, cystatin C, urine NAG levels and outcomes including AKI development and mortality. Results: During a median follow-up of 6.1 months, 17 patients experienced AKI and 21 patients died. In the AUC analysis for predicting the development of AKI within 6 months, those of serum Cr and cystatin C levels and urine NAG level were 0.562, 0.802, and 0.833, respectively. On multivariate Cox-regression analysis, AKI significantly occurred more frequently with higher serum cystatin C (HR, 21.168; P=0.010) and urine NAG levels (HR, 1.023; P<0.001). Patients significantly survived longer with lower serum cystatin C (HR, 0.273; P=0.003), urine NAG levels (HR, 0.983; P=0.001), and Child-Pugh scores (HR, 0.627; P=0.001). Patients with the serum cystatin C ³ 1.0 mg/L and urine NAG ³ 31 U/g urinary Cr (n=12) showed more AKI development (P<0.001) and higher mortality (P<0.001) than other patients on Kaplan-Meier plots. Conclusions: Serum cystatin C and urine NAG levels are strong predictors for AKI development and mortality in patients with decompensated cirrhosis. In addition, the use of urine NAG in conjunction with cystatin C may provide a more accurate prediction.

Clinical usefulness of psoas muscle thickness for the diagnosis of sarcopenia in patients with liver cirrhosis

( Dae Hoe Gu ),( Moon Young Kim ),( Yeon Seok Seo ),( Sang Gyune Kim ),( Han Ah Lee ),( Tae Hyung Kim ),( Young Kul Jung ),( Altay Kandemir ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Jong 대한간학회 2018 Clinical and Molecular Hepatology(대한간학회지) Vol.24 No.3

Background/Aims: The most widely used method for diagnosing sarcopenia is the skeletal muscle index (SMI). Several studies have suggested that psoas muscle thickness per height (PMTH) is also effective for detecting sarcopenia and predicting prognosis in patients with cirrhosis. The aim of this study was to evaluate the optimal cutoff values of PMTH for detecting sarcopenia in cirrhotic patients. Methods: All cirrhotic patients who underwent abdominal computed tomography (CT) scan including L3 and umbilical levels for measuring SMI and transverse psoas muscle thickness, respectively, were included. Two definitions of sarcopenia were used: (1) sex-specific cutoffs of SMI (≤52.4 ㎠/㎡ in men and ≤38.5 ㎠/㎡ in women) for SMIsarcopenia and (2) cutoff of PMTH (<16.8 mm/m) for PMTH-sarcopenia. Results: Six hundred fifty-three patients were included. The average age was 53.6±10.2 years, and 499 patients (76.4%) were men. PMTH correlated well with SMI in both men and women (P<0.001). Two hundred forty-one (36.9%) patients met the criteria for SMI-sarcopenia. The best PMTH cutoff values for predicting SMI-sarcopenia were 17.3 mm/m in men and 10.4 mm/m in women, and these were defined as sex-specific cutoffs of PMTH (SsPMTH). The previously published cutoff of PMTH was defined as sex-nonspecific cutoff of PMTH (SnPMTH). Two hundred thirty (35.2%) patients were diagnosed with SsPMTH-sarcopenia, and 280 (44.4%) patients were diagnosed with SnPMTH-sarcopenia. On a multivariate Cox regression analysis, SsPMTH-sarcopenia (hazard ratio [HR], 1.944; 95% confidence interval [CI], 1.144-3.304; P=0.014) was significantly associated with mortality, while SnPMTH-sarcopenia was not (HR, 1.446; 95% CI, 0.861-2.431; P=0.164). Conclusions: PMTH was well correlated with SMI in cirrhotic patients. SsPMTH-sarcopenia was an independent predictor of mortality in these patients and more accurately predicted mortality compared to SnPMTH-sarcopenia. (Clin Mol Hepatol 2018;24:319-330)

Cyanoacrylate injection versus band ligation for bleeding from cardiac varices along the lesser curvature of the stomach

( Sang Jung Park ),( Yong Kwon Kim ),( Yeon Seok Seo ),( Seung Woon Park ),( Han Ah Lee ),( Tae Hyung Kim ),( Sang Jun Suh ),( Young Kul Jung ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Jae 대한간학회 2016 Clinical and Molecular Hepatology(대한간학회지) Vol.22 No.4

Background/Aims: Practice guidelines recommend endoscopic band ligation (EBL) and endoscopic variceal obturation (EVO) for bleeding from esophageal varices and fundal varices, respectively. However, the optimal treatment for bleeding from cardiac varices along the lesser curvature of the stomach (GOV1) remains undefined. This retrospective study compared the efficacy between EBL and EVO for bleeding from GOV1. Methods: Patients treated by EBL or EVO via cyanoacrylate injection for bleeding from GOV1 were enrolled. Patients diagnosed with hepatocellular carcinoma or treated with endoscopic injection sclerotherapy were excluded. Results: The study included 91 patients treated for bleeding from GOV1. The mean age was 56.3±10.9 years (mean±SD), and 78 of them (85.7%) were men. Overall, 51 and 40 patients were treated with EBL and EVO, respectively. A trend for a higher hemostasis rate was noted in the EVO group (100%) than in the EBL group (82.6%, P=0.078). Varices rebled in 15 patients during follow-up. The rebleeding rate was significantly higher in the EBL group than in the EVO group (P=0.004). During follow-up, 13 patients died (11 in the EBL group and 2 in the EVO group); the survival rate was marginally significant between two groups (P=0.050). The rebleeding-free survival rate was significantly higher in the EVO group than in the EBL group (P=0.001). Conclusions: Compared to EBL, EVO offered significantly lower rebleeding rates, significantly higher rebleeding-free survival rates, and a trend for higher hemostasis and survival rates. EVO appears to be the better therapeutic option for bleeding from GOV1. (Clin Mol Hepatol 2016;22:487-494)

Sarcopenia Is an Independent Predictor for Mortality in Patients with Liver Cirrhosis

( Han Ah Lee ),( Sang Gyune Kim ),( Moon Young Kim ),( Yeon Seok Seo ),( Tae Hyung Kim ),( Sang Jun Suh ),( Young Kul Jung ),( Ji Hoon Kim ),( Hyunggin An ),( Hyung Joon Yim ),( Jong Eun Yeon ),( Kwan 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Various studies suggested that sarcopenia is very frequent in patients with liver cirrhosis and it is an independent predictor of mortality in these patients. This study was evaluate the prevalence and clinical impact of sarcopenia in patients with liver cirrhosis Methods: We enrolled all patients with liver cirrhosis who performed abdominal CT and laboratory tests including serum Cr and cystatin C levels. Muscle mass was measured at the third lumbar vertebrae level using the NIH ImageJ software. Sarcopenia was defined by using previously published sex-specific cutoffs (Ł52.4 cm2/m2 in males and Ł38.5 cm2/m2 in female). Results: Six-hundred fifty-four patients with liver cirrhosis were enrolled. Age was 53.6±10.2 years and 499 patients (76.3%) were men. Sarcopenia was noted in 241 patients (36.9%). Sarcopenia was more frequently found in men (45.1%) compared to women (10.3%; P<0.001) and was significantly more frequently noted in patients with Child-Pugh grades B (42.2%) or C (46.4%) compared to those with Child-Pugh grade A (30.1%). On multivariate analysis, male sex, lower body mass index, and Child-Pugh grade were independent predictors for the presence of sarcopenia. During 19.3±13.1 months of follow-up, 60 patients (9.2%) died. On multivariate analysis, non-viral etiology (HR, 2.049; 95% CI, 1.155-3.632; P=0.014), the presence of sarcopenia (HR, 1.894; 95% CI, 1.116-3.214; P=0.018), higher serum creatinine level (HR, 4.093; 95% CI, 1.827-9.169; P=0.001), lower serum sodium level (HR, 0.927; 95% CI, 0.875-0.981; P=0.009), and Child-Pugh grade B (HR, 3.097; 95% CI, 1.476-6.496; P=0.003) or C (HR, 4.740; 95% CI, 2.028-11.078; P<0.001) were significantly associated mortality. Conclusions: Sarcopenia was frequently combined in patients with liver cirrhosis and the prevalence was associated with liver function. Presence of sarcopenia was significantly associated with mortality in these patients.