Resistance Model for Reliability Analysis of Existing Steel Girder Bridges

Jun Sik Eom(엄준식) 한국신뢰성학회 2013 신뢰성응용연구 Vol.13 No.4

Because of financial and safety concerns, there are needs for more accurate prediction of bridge behavior. Underestimation of the bridge load carrying capacity can have serious economic consequences, as deficient bridges must be repaired or rehabilitated. Therefore, the knowledge of the actual bridge behavior under live load may lead to a more realistic calculation of the load carrying capacity and eventually this may allow for more bridges to remain in service with or without minor repairs. The presented research is focused on the reliability evaluation of the actual load carrying capacity of existing bridges based on the field testing. Seventeen existing bridges were tested under truck load to confirm their adequacy of reliability. The actual response of existing bridge structures under live load is measured. Reliability analysis is performed on the selected representative bridges designed in accordance with AASHTO codes for bridge component (girder). Bridges are first evaluated based on the code specified values and design resistance. However, after the field testing program, it is possible to apply the experimental results into the bridge reliability evaluation procedures. Therefore, the actual response of bridge structures, including unintentional composite action, partial fixity of supports, and contribution of nonstructural members are considered in the bridge reliability evaluation. The girder distribution factors obtained from the tests are also applied in the reliability calculation. The results indicate that the reliability indices of selected bridges can be significantly increased by reducing uncertainties without sacrificing the safety of structures, by including the result of field measurement data into calculation.

Metabolic profiling of serum and urine in lactating dairy cows affected by subclinical ketosis using proton nuclear magnetic resonance spectroscopy

( Jun Sik Eom ),( Shin Ja Lee ),( Hyun Sang Kim ),( Youyoung Choi ),( Seong Uk Jo ),( Sang Suk Lee ),( Eun Tae Kim ),( Sung Sill Lee ) 한국축산학회 2022 한국축산학회지 Vol.64 No.2

Ketosis is associated with high milk yield during lactating or insufficient feed intake in lactating dairy cows. However, few studies have been conducted on the metabolomics of ketosis in Korean lactating dairy cows. The present study aimed to investigate the serum and urine metabolites profiling of lactating dairy cows through proton nuclear magnetic resonance (¹H-NMR) spectroscopy and comparing those between healthy (CON) and subclinical ketosis (SCK) groups. Six lactating dairy cows were categorized into CON and SCK groups. All experimental Holstein cows were fed total mixed ration. Serum and urine samples were collected from the jugular vein of the neck and by hand sweeping the perineum, respectively. The metabolites in the serum and urine were determined using ¹H-NMR spectroscopy. Identification and quantification of metabolites was performed by Chenomx NMR Suite 8.4 software. Metabolites statistical analysis was performed by Metaboanalyst version 5.0 program. In the serum, the acetoacetate level was significantly (p < 0.05) higher in the SCK group than in the CON group, and whereas acetate, galactose and pyruvate levels tended to be higher. CON group had significantly (p < 0.05) higher levels of 5-aminolevulinate and betaine. Indole-3-acetate, theophylline, p-cresol, 3-hydroxymandelate, gentisate, N-acetylglucosamine, N-nitrosodimethylamine, xanthine and pyridoxine levels were significantly (p < 0.05) higher in the urine of the SCK group than that in the CON group, which had higher levels of homogentisate, ribose, gluconate, ethylene glycol, maltose, 3-methyl-2-oxovalerate and glycocholate. Some significantly (p < 0.05) different metabolites in the serum and urine were associated with ketosis diseases, inflammation, energy balance and body weight. This study will be contributed useful a future ketosis metabolomics studies in Korea.

Truck Load Effects for Michigan Bridges

Jun-Sik Eom,Andrzej S. Nowak 상지대학교 환경과학기술연구소 2004 환경과학연구 Vol.10 No.1

  The paper provides a statistical background for bridge live load model, including static and dynamic components, and girder distribution factors. The static portion of live load includes truck weights (gross vehicle weight), axle loads, load effects (moments, shear forces, strain and stress). The data is based on field measurements carried out in Michigan. A considerable percentage of illegally overloaded trucks was observed, in particular on bridges located far from truck weigh stations. The cumulative distribution functions are shown for various locations in Michigan, and they are strongly site-specific. Dynamic load was measured on girder bridges. It turned out that there is almost no correlation between static and dynamic portions of live load. This means that dynamic load factor decreases for increasing static live load, or dynamic load factor decreases for heavier trucks. For a single heavy truck, the dynamic load factor is less than 0.20, and for two trucks side-by-side, dynamic load factor is less than 0.10. Girder distribution factors were also based on measurements, and compared to analytical values calculated using the code-specific procedures. It was observed that the code specified values are conservative in most cases. The statistical data can be used to update a basis for reliability analysis of girder bridges.

Metabolomics comparison of rumen fluid and milk in dairy cattle using proton nuclear magnetic resonance spectroscopy

Eom, Jun Sik,Kim, Eun Tae,Kim, Hyun Sang,Choi, You Young,Lee, Shin Ja,Lee, Sang Suk,Kim, Seon Ho,Lee, Sung Sill Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.2

Objective: The metabolites that constitute the rumen fluid and milk in dairy cattle were analyzed using proton nuclear magnetic resonance (1H-NMR) spectroscopy and compared with the results obtain for other dairy cattle herds worldwide. The aim was to provide basic dataset for facilitating research on metabolites in rumen fluid and milk. Methods: Six dairy cattle were used in this study. Rumen fluid was collected using a stomach tube, and milk was collected using a pipeline milking system. The metabolites were determined by 1H-NMR spectroscopy, and the obtained data were statistically analyzed by principal component analysis, partial least squares discriminant analysis, variable importance in projection scores, and metabolic pathway data using Metaboanalyst 4.0. Results: The total numbers of metabolites in rumen fluid and milk were measured to be 186 and 184, and quantified as 72 and 109, respectively. Organic acid and carbohydrate metabolites exhibited the highest concentrations in rumen fluid and milk, respectively. Some metabolites that have been associated with metabolic diseases (acidosis and ketosis) in cows were identified in rumen fluid, and metabolites associated with ketosis, somatic cell production, and coagulation properties were identified in milk. Conclusion: The metabolites measured in rumen fluid and milk could potentially be used to detect metabolic diseases and evaluate milk quality. The results could also be useful for metabolomic research on the biofluids of ruminants in Korea, while facilitating their metabolic research.

단.중경간 강형교 거더의 횡분배 모델

엄준식 ( Eom Jun-sik ),( Andrzej S. Nowak ),노병철 ( Lho Byeong-cheol ) 한국구조물진단유지관리공학회 2003 한국구조물진단유지관리공학회 논문집 Vol.7 No.2

The objective of this work is to verify the Code specified girder distribution factors for short and medium span bridges. To accomplish this objective, field tests were carried out on seventeen simply supported highway bridges. This paper presents the procedure and results of field tests that were performed to verify girder distribution factors. Finite Element analyses previously performed at the University of Michigan indicated that in most cases currently used girder distribution factors specified in AASHTO Codes are too conservative. However, these studies also showed that for short spans and short girder spacings, the girder distribution factors can be too permissive. Therefore, this paper focused on experimental evaluation of girder distribution factors for short and medium span steel girder bridges. The results were compared with the distribution factors specified by AASHTO Standard (2000) and AASHTO LRFD Code (1998). It has been found that the measured girder distribution factors are lower than AASHTO values in most cases, and sometimes the code specified values are overly conservative. The research work involved formulation of the testing procedure, selection of structure, installation of equipment, measurements, and interpretation of the results.

양성자 핵자기공명분광기를 이용한 고온스트레스에 따른 Holstein 수소의 반추위액과 혈액 내 대사체 프로파일링 연구

엄준식(Jun Sik Eom),이신자(Shin Ja Lee),이상석(Sang Suk Lee),서성원(Seongwon Seo),박성민(Seong Min Park),이성실(Sung Sill Lee) 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.1

서울 서부의 기피시설에서 재탄생된 공공시설들의 특성

엄준식(Eom, Jun-Sik),안대환(An, Dai-Whan) 대한건축학회 2018 대한건축학회논문집 Vol.34 No.11

The aim of this study is to understand the direction of planning for regeneration based on six representative cases of western part of Seoul that were regenerated from the unpleasant facilities since the 20th century. In particular, the similarities and differences were derived by analyzing the characteristics of the history and the location in terms of the 1st establishment and the regeneration in each cases. As a result, looking the tendency to regenerate the unpleasant facility, it can be seen that there is a correlation between the historical and the locational context when establishing and regenerating. Considering the distinct characteristic of the Location and the history of establishment & regeneration, we could classify the characteristics of public facilities as extroverted tendency and intrinsic tendency analysed by a geographic and an architectural, a programmatic aspects. Therefore, when planning the project regenerated from unpleasant facilities, it should be set considering the locational context and the historical context of establishment & regeneration.

Shared nothing 구조하에서 Chunk - based Caching 전략에 의한 OLAP Query response time의 속도향상.

엄준식(Jun Sik Eom),정병수(Byung Soo Jeong) 한국정보과학회 1999 한국정보과학회 학술발표논문집 Vol.26 No.2Ⅰ

현재 의사결정 시스템을 위한 데이터 웨어하우스는 데이터베이스 분야에서 비약적인 발전을 해오고 있다. 이 분야에서 중요한 사항은 사용자의 질의에 대한 응답시간이다. 사용자로부터 질의가 요구되면 과거의 많은 데이터를 분석하여 적절한 시간 내에 분석결과를 되돌려 줄 수 있어야 하는데 데이터 웨어하우스의 특성상 대용량의 데이터를 저장하고 분석 시에 많은 데이터를 검색해야 하므로 질의 응답시간에 많은 시간이 소요된다. 이 논문에서는 Chunk based caching기법에 의해서 새로이 요구되는 질의에 대해 이미 메모리에 캐시 되어진 내용을 이용하는 방식을 통해 디스크의 I/O 횟수를 줄임으로써 질의 응답시간을 단축시키는 기법을 소개한다. 또한 chunk miss에 대한 처리를 병렬로 수행함으로써 메모리에 캐시되지 않은 내용을 디스크로부터 로드하는 시간을 단축시키는 방법도 아울러 소개한다.

한국에서 유휴 산업시설을 활용한 카페의 재생적 특징 연구 - 대형 근대문화유산의 최근 재생사례를 중심으로 -

엄준식(Eom, Jun-Sik) 대한건축학회 2019 대한건축학회논문집 Vol.35 No.7

In South Korea, the cafes utilizing idle industrial facilities have become popular recently. The purpose of this study is to understand the causes of these social phenomena and to examine the spatial characteristics of cafes regenerated from idle industrial facilities. For the study method, this study first looked at the unique spatial characteristics of Korean cafes and the cause of the increase in the number of cafes regenerated in South Korea. And then it looked at five cases where factories and warehouses built during the industrialization period (1900s~1970s) of South Korea were regenerated as cafes after 2015. Finally, this study was examined the regenerative characteristics that could be transformed from idle industrial facilities into cafes by the type analysis such as the background of the times and the strategy of regeneration. The results showed that three spatial characteristics(large single, multi-functional and emotional) preferred in South Korean cafes appeared in cafes regenerated from idle industrial facilities.

사료 급여 방식에 따른 반추위액 내 휘발성지방산과 단당류 비교 분석과 대사산물 분석

엄준식(Jun-Sik Eom),이신자(Shin-Ja Lee),이유경(Yoo-Gyung Lee),이성실(Sung-Sill Lee) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.12

거세한우 3두를 3x3 Latin square design 시험방법에 적용하여 사료 적응 기간 10일 후 사료 급여 방식에 따른 반추위액 내 휘발성지방산과 단당류 비교 분석 및 대사산물 분석에 대한 연구를 수행하였다. 연구 결과 HPLC와 HPAEC에서 측정되지 않은 휘발성지방산과 단당류들은 1H-NMR에서는 측정이 가능 한 것을 알 수 있었다. 1H-NMR에서 측정된 대사산물중, carbohydrate 계열 대사산물 pyruvate는 사료 급여 전 반추위액에서만 측정 되었으며, succinate는 사료 급여 전·후 에서 모두 측정 되었다. Amino acid 계열 대사산물은 총 9가지가 측정 되었다. Lipid 계열 대사산물 ethylene glycol는 사료 급여 전 Con구에서 유의적(P<0.05)으로 높게 측정 되었다. Aiphatic acylic compounds 계열 대사산물 trimethylamine N-oxide는 유의적인 차이는 보이지 않았다. 이번 연구를 통해 <SUP>1</SUP>H-NMR를 이용하여 반추위액 내 많은 대사산물 측정이 가능한 것을 알 수 있었으며 사료 급여 전·후 급여 방식에 따라 대사산물의 변화가 나타나는 것을 확인 할 수 있었다. This study was conducted to investigate VFA, monosaccharides and metabolites in rumen fluid according to feeding methods. Three castrated Hanwoo steers were used to the 3x3 Latin square design, 10 day for the diet adaptation period. VFA and monosaccharides which were not detected by HPLC and HPAEC however, those were detected by 1H-NMR. Among the metabolites measured by 1H-NMR carbohydrate metabolites, pyruvate was detected only in the rumen fluid before feeding and succinate was detected before and after feeding rumen fluid. In amino acid total 9 metabolites were detected. In lipid metabolites, ethylene glycol was significantly higher (P<0.05) in before feeding Con group. In aliphatic acylic metabolite, trimethylamine N-oxide was no significant difference observed compare to Con group. In this study, many metabolites were observed in the rumen fluid by 1H-NMR, and it confirmed that rumen metabolic products were changed by feeding methods.