Seismic fracture analysis of concrete arch dams incorporating the loading rate dependent size effect of concrete

Amir Pirooznia,Amir Javad Moradloo 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.2

The purpose of this study is to investigate the size effect, loading rate, and smeared crack models in the nonlinear seismic behavior of concrete arch dams. One of the important parameters in the design of arch concrete dams is the tensile strength of unreinforced mass concrete. Various fracture parameters obtained from experimental results reported for concrete in order to study the size-effect is used in this paper. In the present analysis, the smeared crack method is used in finite element analysis of the Morrow Point arch dam subjected to three components of the TAFT earthquake as a case study. The dependence of fracture, and especially of the size effect, on the loading rate is described. Models incorporating nonlinear analysis in three cases with and without the size effect of dam concrete and fluid-structure interaction are employed to evaluate and compare them. The water is taken as an inviscid, compressible fluid, and the foundation is rigid. From the study, it is concluded that the participation of the size effect leads to higher values of maximum displacements and stresses in benchmark points compared to the model that ignores the size effect. The crack initiation criterion based on the maximum tensile stress according to the size effect of concrete, and also the dynamic loading range should be defined. Results show considering fixed smeared crack models used in the concrete specimen as well as the size effect of concrete materials, will lead to the crack profile is more realistic and will represent near to real behavior of concrete fracture. The results are of significant interest for the concrete fracture of dams; hence the loading rate should be adopted for fracture properties obtained in dams.

의료서비스의 지역별 효과적보장 정도: 자궁경부암 검사, 관절염, 고혈압 관리 프로그램을 중심으로

신호성 ( Hosung Shin ),정애숙 ( Aesuk Jeong ),허순임 ( Soonim Huh ) 한국보건사회연구원 2008 保健社會硏究 Vol.28 No.2

본 연구의 목적은 일부 의료서비스의 효과적보장률의 지역적 차이를 조사 분석하는 것이다. 효과적보장은 세계보건기구가 도입한 개념으로 인구집단 전체나 부문별 지표로서 보장률이 아니라 개인 차원에서 의료보장의 효과성을 측정한다. 즉, 개인별 의료이용, 의료요구도, 이용 가능한 의료의 질 자료를 활용하여 의료체계를 효과적보장의 측면에서 평가한다. 본 연구는 2005년 국민건강영양조사를 이용하여 자궁 경부암검사, 관절염, 고혈압의 실질필요(true need)와 의료서비스 이용 결과에 의한 추론을 바탕으로 효과적보장을 산출하였다. 자궁경부암검사의 의료서비스에 대한 실질필요는 여성이라는 특정 성별에 의해 자연적으로 주어진다. 따라서 의료서비스 이용만으로 효과가 인정된다. 관절염의 경우, 건강상의 문제가 단일 증상이 아니라 복합 증상의 발현 정도에 따라 다르게 나타나기 때문에 다문항 설문지를 이용하고 의료서비스에 대한 실질필요도 확률로 계산된다. 고혈압 관리 프로그램은 혈압 조절여부가 조사 가능하여 의료서비스에 대한 실질필요나 처치 후 의료서비스의 질 평가 등 성취도 조사가 가능한 의료서비스이다. 본 연구결과는 광역시도 단위에서 산출되었는데 3가지 의료서비스에 대한 효과적보장은 지역적으로 일정한 경향을 나타내었다. 강원도, 부산, 경상도는 효과적보장의 측면에서 상위그룹에 속하였고 울산, 인천, 제주도는 하위 그룹에 남았다. 의료체계의 반응성을 측정하는 기제로서 효과적보장에 대한 연구는 아직 시작단계에 머물고 있다. 효과적보장은 물리적인 접근성이 보장되었음에도 실질적 보장이 달성되지 못할 때 그 책임은 개인이 져야 하는가의 문제에 주목한다. 이는 저소득 계층에서 의료기관 이용에 실질적 장벽이 있을 경우 개인에 대한 정부의 지원/보조 역할이 여전히 중요한 과제임을 시사한다. The idea of effective coverage has been introduced as a intermediate goal so as to measure the effectiveness of health service coverage at the individual level by WHO. It differentiates from nominal coverage index, which is formulated at the population level. It evaluates health system in terms of utilization, health need, quality of services delivered. The purpose of the study is to calculate the effective coverage and to examine its regional difference among some health services provided (pop-smear screening, hypertension, and arthritis control). The study employes 2005 Korean Health and Nutrition Examination Survey. The true need of pop-smear test is given by gender itself, and the effective of the service associates with the utilization of pop-smear screening exam. Since the diagnosis of arthritis is more complex to detect due to its multiple signs and symptoms, the study calculates its true need with probability using a systematic questionnaire. In case of hypertension control, its effectiveness is easy to identify with merely measuring the blood pressure before and after intervention. The results of the study are displayed by provisional geographic level. Gangwon, Busan, Gyeongsang achieved higher performance, while Ulsan, Incheon, and Jeju belong to the poor group of effective coverage. As a tool of assessing the responsiveness of health system, the application of effective coverage is in a starting phase. It focuses on whether individuals are still responsible for the poor effective coverage in case of achieving physical accessibility. The study results suggest that governmental interventions function as a key mechanism reducing the poor effective coverage, especially for the indigent population.

Cost-Effectiveness Analysis of Different Management Strategies for Detection CIN2+ of Women with Atypical Squamous Cells of Undetermined Significance (ASC-US) Pap Smear in Thailand

Tantitamit, Tanitra,Termrungruanglert, Wichai,Oranratanaphan, Shina,Niruthisard, Somchai,Tanbirojn, Patuou,Havanond, Piyalamporn Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.16

Background: To identify the optimal cost effective strategy for the management of women having ASC-US who attended at King Chulalongkorn Memorial Hospital (KMCH). Design: An Economical Analysis based on a retrospective study. Subject: The women who were referred to the gynecological department due to screening result of ASC-US at King Chulalongkorn Memorial Hospital, a general and tertiary referral center in Bangkok Thailand, from Jan 2008 - Dec 2012. Materials and Methods: A decision tree-based was constructed to evaluate the cost effectiveness of three follow up strategies in the management of ASC-US results: repeat cytology, triage with HPV testing and immediate colposcopy. Each ASC-US woman made the decision of each strategy after receiving all details about this algorithm, advantages and disadvantages of each strategy from a doctor. The model compared the incremental costs per case of high-grade cervical intraepithelial neoplasia (CIN2+) detected as measured by incremental cost-effectiveness ratio (ICER). Results: From the provider's perspective, immediate colposcopy is the least costly strategy and also the most effective option among the three follow up strategies. Compared with HPV triage, repeat cytology triage is less costly than HPV triage, whereas the latter provides a more effective option at an incremental cost-effectiveness ratio (ICER) of 56,048 Baht per additional case of CIN 2+ detected. From the patient's perspective, the least costly and least effective is repeat cytology triage. Repeat colposcopy has an incremental cost-effectiveness (ICER) of 2,500 Baht per additional case of CIN2+ detected when compared to colposcopy. From the sensitivity analysis, immediate colposcopy triage is no longer cost effective when the cost exceeds 2,250 Baht or the cost of cytology is less than 50 Baht (1USD = 31.58 THB). Conclusions: In women with ASC-US cytology, colposcopy is more cost-effective than repeat cytology or triage with HPV testing for both provider and patient perspectives.

한국형 자궁경부 촬영진 ( New Cervicography ) , 세포검사 그리고 HPV-DNA 검사를 이용한 새로운 자궁경부암 검진 모델 ( Model ) 개발

김승조(SJ Kim),박찬규(CK Park),이효표(HP Lee),남궁성은(SE Namkoong),강순범(SB Kang),서호석(HS Saw),이재관(JK Lee),김수녕(SN Kim),김재원(JW Kim),배석년(SN Bae),김찬주(CJ Kim),이근호(KH Lee),이선영(SY Lee),김인호(IH Kim),이찬(C Lee),이정노(JN Lee) 대한산부인과학회 2001 Obstetrics & Gynecology Science Vol.44 No.5

Objective : The false negative rate of conventional cytology is reported to range from 18 to 45%. It is necessary to develop more effective screening strategies that would ideally be more accurate than conventional cytology. This study is designed to investigate the potential of conventional cytology, cervicography, HPV-DNA testing and their combinations as primary screening techniques for cervical neoplasia. The purpose of this project is to develop the models and guidelines for screening tools of cervical cancer of the uterus by evaluating sensitivity, specificity and cost-effectiveness of all the screening methods. Study design : We conducted a screening of random sample of women who visited the department of OB-Gyn. of five different major university hospitals such as Catholic University Hospital, Korea University Hospital, Seoul National University Hospital, Yeonsei University Hospital and Pochon CHA University Bundang CHA Hospital, from May 1, 1996 to April 30, 1999. In a cohort women with an age range of 20 to 70 who underwent routine cytologic screening at Catholic University, Hospital Bundang CHA General Hospital and local clinics from April 1, 1996 to Decomber 31, 2000. cervicography (n=417,125) and testing for HPV-DNA (n=1,347) by the hybrid capture assay were studied for the ability of the cervical cancer screeuing. A new cervicography system with Kim's classification which was developed by Prof. Kim Seung Jo as an adjunctive method for the cervical cancer screening was applied in this cohort study. And then, accuracy, effectivencess, cost-effectiveness of the single or combined screening method were analysed. Result : Sensitivity and specificity of Pap smear were ranged from 55.6% to 83.1% and 72.8% to 88.3% respectively. The combination of Pap smear and cervicography had sensitivity from 89.7% to 98.6%, specificity from 68.2% to 93.2%. With combination of Pap smear, HPV DNA test and cervicography, sensitivity became also highest accuracy among all screening methods from 92.8% to 98.8%. Considering medical charges for diagnosis and social cost occurred by false positive and false negative results, the most cost-effective diagnostic modality was thought to be the combination of Pap smear and cervicography(91,433 won). In patients who were diagnosed as LSIL, colposcopic examination confirmed progression to high grade intraepithelial lesion(HSIL) in 10.7% patients, persistence of LSIL in 55% patients during the 3 year follow-up period. Accuracy of the screening for cervical cancer and CIN can significantly be improved by cytology with new cervicography rather than cytology alone. We concluded that cervicography can be important adjunctive tests for cervical cytology, improving the effectiveness of cervical screening by allowing a more sensitive detection of cervical neoplasia.

Consolidation of Unsaturated Drainage Well Foundation with Smear Effect under Time-Dependent Loading

Yuanchun Huang,Tianyi Li,Xianlei Fu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

In real practice, the construction of drainage wells is always accompanied by smear effect, whereas it is scarcely discussed in the field of unsaturated soils. In this case, on the basis of the widely-accepted consolidation theory for unsaturated stratum by Fredlund, this paper studies the equal strain consolidation characteristics of unsaturated foundation with drain wells affected by smear effect under time-varying loading (exponential loading as a case). Firstly, with the consideration of corresponding boundary conditions, the governing equations under the equal strain hypothesis are obtained. Afterwards, decoupling process, constant variation method and Fourier series expansion theory are utilized to get the analytical solutions, which are then verified to be credible by means of the finite difference method. Finally, the consolidation patterns of the drainage well foundation modeling in unsaturated soils are studied against hydraulic coefficients, modeling sizes and loading parameter. It reveals that the smear effect can significantly restrain the consolidation process of the foundation by drain wells, while different parameters will lead to various results.

Effectiveness of an organized cervical cancer screening program in Korea: Results from a cohort study

Jun, Jae Kwan,Choi, Kui Son,Jung, Kyu Won,Lee, Hoo-Yeon,Gapstur, Susan M.,Park, Eun-Cheol,Yoo, Keun-Young Wiley Subscription Services, Inc., A Wiley Company 2009 International journal of cancer: Journal internati Vol.124 No.1

<P>Although the value of cervical cancer screening is widely acknowledged, the effectiveness of an organized cervical cancer screening program in Korea has never been evaluated. We investigated the associations of the frequency of cervical cancer screening with cervical cancer incidence using data from a large prospective cohort study. In this analysis, 253,472 women without a hysterectomy or previous cancer diagnosis were included. Follow-up was between 1995 and 2002. Frequency of Pap smear testing was determined by searching the National Health Examination Database. Using the Korean Central Cancer Registry, 248 cases of invasive cervical cancer and 346 cases of carcinoma in situ (CIS) of the cervix were identified. Subjects screened 2 or more times showed a 71% (corrected reduction 60%) and a 66% (corrected reduction 53%) reduced risk of invasive cervical cancer and CIS of the cervix, respectively, as compared with unscreened subjects [relative risk (RR) = 0.29; 95% confidence interval (CI) = 0.20–0.45; RR = 0.34; 95% CI = 0.25–0.46, respectively]. Women with a normal or benign pap smear had a statistically significantly lower risk of invasive cervical cancer and CIS of cervix compared with those never screened. In age-stratified analyses, there was a significant reduction in cervical cancer incidence among women aged 30 and over who were screened 2 or more times compared with women never screened. The results of this prospective cohort study show that regular screening of cervical cancer reduces invasive cervical cancer incidence and CIS of the cervix among Korean women. © 2008 Wiley-Liss, Inc.</P>

Cost-Effectiveness of Korea's National Cervical Cancer Screening Program

Cho, Eun,Kang, Moon Hae,Choi, Kui Son,Suh, MiNa,Jun, Jae Kwan,Park, Eun-Cheol Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.7

Background: Cervical cancer, which is common in developing countries, is also a major health issue in Korea. Our aim was to evaluate the cost-effectiveness of Korea's National Cancer Screening Program (NCSP), implemented in 1999. Materials and Methods: The target population was Korean women 30 years or over who were invited to take part in the NCSP in 2002-2007. By merging NCSP records with Korean Central Cancer Registry data, patients diagnosed with cervical cancer who had been screened were assigned to a "screened group," while patients diagnosed elsewhere were assigned to a "non-screened group." Clinical outcomes were measured in terms of life-years saved (LYS), derived from 5-year mortality rates supplied by the Korean National Health Insurance Corporation and National Statistical Office. Direct and travel costs associated with screening were evaluated from the perspective of the payer, the NCSP. Results: A diagnosis via screening was associated with 2.30 LYS, and the incremental cost-effectiveness ratio (ICER) estimate for screening was 7,581,679 KW/LYS (6,727 USD/LYS). ICER estimates were lower for older patients (${\geq}$ 50 years) than younger patients (4,047,033 KW/LYS vs 5,680,793 KW/LYS). The proportion of early-stage cancers detected was 16.3% higher in the screened group. Conclusions: In light of Korea's per capita gross domestic product (32,272 USD in 2012), the current NCSP's incremental cost per LYS appears acceptable.

점토의 압밀계수에 대한 이방성

강병희,이윤규,김경태 한국지반공학회 1999 한국지반공학회논문집 Vol.15 No.1

점토지반의 압밀계수에 대한 이방성을 연구하기 위하여 인공퇴적점토시료로서 Rowe형 압밀시험기와 재래식 일반 압밀시험기를 이용하여 일련의 압밀시험을 수행하였다. 시험결과 Rowe형 압밀시험기에 의해서 구한 내향수평압밀계수는 일반 압밀시험기에 의한 연직 압밀계수의 약 2배이었다. 또한, 연직모래배수재의 설치로 인한 스미어 영향은 과압밀응력범위에서 특히 크며 압밀응력이 증가할수록 감소하였다. In order to investigate the anisotropy in the coefficient of consolidation of the clay deposit, a series of consolidation tests were carried out on the artificially deposited clay sample by both Rowe-type and conventional consolidometers. The results of the tests showed that the coefficient of consolidation for radially inward drainage by Rowe-type consolidometer was about two times larger than that for vertical drainage by the conventional consolidometer. The smear effect caused by vertical sand drain installation was found to be significant, especially in the overconsolidated region, but smaller with the increase in consolidation pressure.

현장계측사례를 이용한 밴드 드레인공법의 압밀이론에 관한 연구

김현태,구남실,김병일 명지대학교 대학원 1999 대학원논문집 Vol.3 No.-

Vertical drain method is being used as effective ground improving for soft clay layer with small shear strength and high compressibility. chiefly applying to preloading method. This method is being used as sand drain, pack drain, paper drain and etc. The theory solution of vertical drain. which was originated by Barron(1948), was developed by Yoshikuni(1974). Hansbo(1981), and Onoue(1988). This theory solution shows the degree of consolidation differences by each variable in design and this study compared the consolidation theory of vertical drain with measured values and the difference between consolidation theory of vertical drain and measured values was analyzed. In this study, consolidation theory of paper drain was analyzed by three sides. First compared analyzed smear effect factor and well resistance factor of difference equation concerned about variability. Second, compared consolidation curve with measured curve by measured date of field. The last, compared measured settlement with predict settlement. As a result of comparison between observation of field and theoretical method, the theory of Onoue and Hansbo intend to estimate consolidation rate lowly and Baron theory by assumed c_h = c_v and measured values are nearly the same time-settlement behaviour.

Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches

Ireneusz Marzec,Łukasz Skarżyńsk,Jerzy Bobiński,Jacek Tejchman 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.5

The paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack and isotropic damage model were applied. Finally, an elasto-plastic-damage model was used. To ensure mesh-independent FE results, to describe strain localization in concrete and to capture a deterministic size effect, all models were enhanced in a softening regime by a characteristic length of micro-structure by means of a non-local theory. Bond-slip between concrete and reinforcement was considered. The numerical results were directly compared with the corresponding laboratory tests performed by Walraven and Lehwalter (1994). The advantages and disadvantages of enhanced models to model the reinforced concrete behaviour were outlined.