• Title/Summary/Keyword: Meta study

Search Result 2,600, Processing Time 0.025 seconds

A Study on the Effect of the Kinds and Replacement Ratios of Mineral Admixtures on the Development of Chloride Invasion Resistance Property of Concrete Immersed in Salt Water (혼화재 종류 및 치환율이 염수에 침지한 콘크리트의 내염성능 향상에 미치는 영향에 관한 연구)

  • Yoo Jae-Kang;Kim Dong-Seuk;Park Sang-Joon;Won Chul
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • v.y2004m10
    • /
    • pp.71-76
    • /
    • 2004
  • This paper investigate that the effect of the concrete containing mineral admixtures(pozzolanic materials such as fly-ash, ground granulated blast-furnace slag, silica fume and meta kaolin) on the resistance properties to chloride ion invasion. The purposed testing procedure was applied to the concrete added mineral admixtures for $3\sim4$ replacement ratios under W/B ratios ranged from 0.40 to 0.55. Specimens were immersed in $3.6\%$ NaCl solution for 330 days, and penetration depth, water soluble chloride contents and acid soluble chloride contents were measured in 28, 91, 182 and 330 days. Then, diffusion coefficient were calculated using total chloride contents. As a results. the kinds of mineral admixture and replacement ratios had a great effect on the resistance property of the concrete to chloride ion invasion compared with the plain concrete. And the optimal replacement ratios of mineral admixture had a limitation for each admixtures. The amount of acid soluble chloride ions and water soluble chloride ions were varied with the kinds of mineral admixtures and the penetration depth from the concrete skin. Chloride diffusion coefficient of each concretes decreased with the time elapsed. and the diffusion coefficients of the concrete immersed salt water for 330 days had a establishment with the compressive strength measured before immersing.

  • PDF

Optimization for Configuration and Material Cost of Helical Pile Using Harmony Search Algorithm (하모니서치 알고리즘을 이용한 헬리컬 파일의 형상 및 재료비 최적 설계기법에 대한 연구)

  • Na, Kyunguk;Lee, Dongseop;Lee, Hyungi;Choi, Hangseok
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.35 no.2
    • /
    • pp.377-386
    • /
    • 2015
  • The helical pile is a manufactured steel pile consisting of one or more helix-shaped bearing plates affixed to a central shaft. This pile is installed by rotating the shaft into the ground to support structural loads. Advantages of the helical pile are no need for boring or grout process, and ability to install a pile foundation with relatively light devices. In this study, an optimized design method for helical piles is proposed to minimize the material cost with consideration of the load bearing capacity obtained by the cylindrical shear method. The harmony search meta-heuristic algorithm was adopted for optimization process. The optimized design was verified by comparing with the 2009 International building code. It is noted that the optimization for the configuration of helical piles along with material cost proves to be an out-performed tool in designing helical pile foundation with economic feasibility.

Influence of Perineural Invasion on Survival and Recurrence in Patients with Resected Pancreatic Cancer

  • Zhang, Jun-Feng;Hua, Rong;Sun, Yong-Wei;Liu, Wei;Huo, Yan-Miao;Liu, De-Jun;Li, Jiao
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.9
    • /
    • pp.5133-5139
    • /
    • 2013
  • Background: Perineural invasion (PNI) has been reported as one of the sources of locoregional recurrence in resected pancreatic cancer (PC). However the impact of PNI in resected pancreatic cancer remains controversial. The purpose of this study was to determine the association between PNI status and clinical outcomes. Methods: Publications were identified which assessed prognostic significance of PNI status in resected pancreatic cancer up to February 2013. A meta-analysis was performed to clarify the association between PNI status and clinical outcomes. Results: A total of 21 studies met the inclusion criteria, covering 4,459 cases. Analysis of these data showed that intrapancreatic PNI was correlated with reduced overall survival only in resected pancreatic ductal adenocarcinoma (PDAC) patients (HR=1.982, 95%CI: 1.526-2.574, p=0.000). Extrapancreatic PNI was correlated with reduced overall survival in all resected pancreatic cancer patients (HR=1.748, 95%CI: 1.372-2.228, p=0.000). Moreover, intrapancreatic PNI status may be associated with tumor recurrence in all resected pancreatic cancer patients (HR=2.714, 95%CI: 1.885-3.906, p=0.000). Conclusion: PNI was an independent and poor prognostic factor in resected PDAC patients. Moreover, intrapancreatic PNI status may be associated with tumor recurrence.

A Systematic Review of Psychological Distress as a Risk Factor for Recurrent Cardiac Events in Patients with Coronary Artery Disease (관상동맥질환자의 심질환 재발에 영향을 미치는 심리적 디스트레스에 대한 체계적 문헌고찰)

  • Park, Jin-Hee;Bae, Sun-Hyoung
    • Journal of Korean Academy of Nursing
    • /
    • v.41 no.5
    • /
    • pp.704-714
    • /
    • 2011
  • Purpose: The purpose of this study was to determine whether psychological distress is an independent risk factor for recurrent cardiac events in patients with coronary artery disease (CAD). Methods: A prospective cohort of studies that measured psychological distress and the incidence of recurrent cardiac events in the adult population were included. Three computerized databases were assessed (PubMed, CINAHL, and PSYCINFO). Meta-analysis was conducted using a random-effects model to determine summary estimates of risks of major recurrent cardiac events associated with each psychological distress. Of 506 publications identified, 33 met inclusion criteria, and 24 studies were used to estimate effect size of psychological distress on recurrent cardiac events. Results: Mean number in the research sample was 736 and mean time of follow-up was 4.0 years. Depression, anxiety, anger, and hostility as psychological factors were studied. According to estimation of effect size using random model effect, depression (OR=1.39, 95% CI: 1.22-1.57), anxiety (OR=1.22, 95% CI: 0.96-1.56), and anger/hostility (OR=1.29, 95% CI: 1.07-1.57) CAD patients in significantly increased risk for recurrent cardiac events. Conclusion: Finding suggests that psychological distress in forms of depression, anxiety, anger, and hostility impact unfavorably on recurrent cardiac events in CAD patients.

A Performance Comparison of Multi-Label Classification Methods for Protein Subcellular Localization Prediction (단백질의 세포내 위치 예측을 위한 다중레이블 분류 방법의 성능 비교)

  • Chi, Sang-Mun
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.18 no.4
    • /
    • pp.992-999
    • /
    • 2014
  • This paper presents an extensive experimental comparison of a variety of multi-label learning methods for the accurate prediction of subcellular localization of proteins which simultaneously exist at multiple subcellular locations. We compared several methods from three categories of multi-label classification algorithms: algorithm adaptation, problem transformation, and meta learning. Experimental results are analyzed using 12 multi-label evaluation measures to assess the behavior of the methods from a variety of view-points. We also use a new summarization measure to find the best performing method. Experimental results show that the best performing methods are power-set method pruning a infrequently occurring subsets of labels and classifier chains modeling relevant labels with an additional feature. futhermore, ensembles of many classifiers of these methods enhance the performance further. The recommendation from this study is that the correlation of subcellular locations is an effective clue for classification, this is because the subcellular locations of proteins performing certain biological function are not independent but correlated.

Initial Small Data Reveal Rumor Traits via Recurrent Neural Networks (초기 소량 데이터와 RNN을 활용한 루머 전파 추적 기법)

  • Kwon, Sejeong;Cha, Meeyoung
    • Journal of KIISE
    • /
    • v.44 no.7
    • /
    • pp.680-685
    • /
    • 2017
  • The emergence of online media and their data has enabled data-driven methods to solve challenging and complex tasks such as rumor classification problems. Recently, deep learning based models have been shown as one of the fastest and the most accurate algorithms to solve such problems. These new models, however, either rely on complete data or several days-worth of data, limiting their applicability in real time. In this study, we go beyond this limit and test the possibility of super early rumor detection via recurrent neural networks (RNNs). Our model takes in social media streams as time series input, along with basic meta-information about the rumongers including the follower count and the psycholinguistic traits of rumor content itself. Based on analyzing millions of social media posts on 498 real rumors and 494 non-rumor events, our RNN-based model detected rumors with only 30 initial posts (i.e., within a few hours of rumor circulation) with remarkable F1 score of 0.74. This finding widens the scope of new possibilities for building a fast and efficient rumor detection system.

DEM Generation by the Matching Line Using Exterior Orientation Parameters of the IKONOS Geo Imagery (IKONOS 위성영상의 외부표정요소로부터 정합선 수립에 의한 DEM 생성)

  • Lee, Hyo-Seong;Ahn, Ki-Weon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.24 no.4
    • /
    • pp.367-376
    • /
    • 2006
  • This study determines the optimum polynomial of exterior orientation parameters(EOPs) as a function of line number of linear array scanner. To estimate priori EOPs, meta data of IKONOS scene and ground control points are used. We select a first order polynomial and a constant for position elements modeling and rotation elements modeling. Positioning accuracy of the determined EOPs is compared with that of RPCs bias-corrected by the least squares adjustment. There is almost no difference between accuracies of the two methods. To obtain digital elevation model(DEM), matching line is established by the EOPs. The DEM is compared with DEM generated by ERDAS IMAGINE software, which utilizes the bias-corrected RPCs. Height differences of DEMs by the two methods are ranged within a allowable standard deviation. The produced DEM, therefore, shows accuracy similar to the verified method.

A Study of New Technique Development for Creep Evaluation of Heat Resistant Steel Weldment(I) (내열강 용접부의 크리프 평가 신기술 개발에 관한 연구)

  • 유효선;백승세;권일현;이송인
    • Journal of Welding and Joining
    • /
    • v.20 no.6
    • /
    • pp.30-30
    • /
    • 2002
  • It has been reported that the creep characteristics on weldment which is composed of weld metal(W.M), fusion line(F.L), heat-affected zone(HAZ), and base meta(B.M) could be unpredictably changed in severe service conditions such as high temperature and high pressure. However, the studies done on creep damage in power plant components have been mostly conducted on B.M and not the creep properties of the localized microstructures in weldment have been thoroughly investigated yet. In this paper, it is investigated the creep characteristics for three microstructures like coarse-grain HAZ(CGHAZ), W.M, and B.M in X20CrMoV121 steel weldment by the small punch-creep-(SP-Creep) test using miniaturized specimen(l0×10×0.5mm). The W.M microstructure possesses the higher creep resistance and shows lower creep strain rate than the B.M and CGHAZ. In the lower creep load the highest creep strain rate is exhibited in CGHAZ, whereas in the higher creep load the B.M represents the high creep strain rate. The power law correlation for all microstructures exists between creep rate and creep load at 600℃. The values of creep load index (n) based on creep strain rate for B.M, CGHAZ, and W.M are 7.54, 4.23, and 5.06, respectively and CGHAZ which shows coarse grains owing to high welding heat has the lowest creep loade index. In all creep loads, the creep life for W.M shows the highest value.

Preparation and Characterization of Polyamide Thin Film Composite Reverse Osmosis Membranes Using Hydrophilic Treated Microporous Supports (친수성 처리된 다공성 지지체를 이용한 폴리아마이드 박막 역삼투 복합막 제조 및 특성 분석)

  • Son, Seung Hee;Jegal, Jonggeon
    • Membrane Journal
    • /
    • v.24 no.4
    • /
    • pp.317-324
    • /
    • 2014
  • It is very well known that the conventional polyamide (PA) thin film composite (TFC) reverse osmosis (RO) membranes have excellent permselective properties, but their chlorine tolerance is not good enough. In this study, to improve such chlorine tolerance, microporous membranes containing hydrophilic functional groups such as -COOH were used as a support to prepare PA TFC RO membranes, employing the conventional interfacial polymerization method. Meta-phenylene diamine (MPD) and 2,6-diamine toluene (2,6-DAT) were used as diamine monomers and tri-mesoyl chloride (TMC) as an acid monomer. The membranes prepared were characterized using various instrumental analytical methods and permeation test set-up. The flux obtained from the membranes prepared so was more than $1.0m^3/m^2day$ at 800 psi of operating pressure, while the salt rejection was over 99.0%. The chlorine tolerance of them was also found to be better than that of the membrane prepared by using conventional polysulfone support without hydrophilic functional groups.

The Analysis of Ethanol Distribution Level in Biological Specimens (생체 시료중에서 Ethanol 농도 분포에 관한 연구)

  • Hong, Hoon-Gi;Kim, Dong-Wook
    • Analytical Science and Technology
    • /
    • v.11 no.3
    • /
    • pp.222-228
    • /
    • 1998
  • Five kinds of packed column and two kinds of capillary column were used to get optimum condition for ethanol analysis by using fifteen different volatile, low molecular weight organic substances. Only two columns, Gaskuropack 54 and DB-1, showed good separation efficiency. In the adding salt-effect experiment 0.6N - perchloric acid, 1M - meta-phosphoric acid and saturated NaCl solution were used for alcohol concentration measurement of biological fluids and tissue specimens. Among adding salt experiment, adding saturated NaCl solution showed the most stable value of alcohol concentration. This fact might be due to the increased vaporization of alcohol in the saturated NaCl solution. In the time-course of blood alcohol concentration, the alcohol level was lineary decreased to the diameter of vessel containing specimens. This result was interpreted in view of ethanol level, weight, water content, and hematocrit value. The ethanol distribution levels were measured from samples of blood and tissue obtained from 25 postmortems cases investigated by NISI. This study showed that the distribution level was decreased in order of brain, blood, kidney, spleen, liver, and lung.

  • PDF