• 제목/요약/키워드: SIR Model

검색결과 68건 처리시간 0.023초

Information Dissemination Model of Microblogging with Internet Marketers

  • Xu, Dongliang;Pan, Jingchang;Wang, Bailing;Liu, Meng;Kang, Qinma
    • Journal of Information Processing Systems
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    • 제15권4호
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    • pp.853-864
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    • 2019
  • Microblogging services (such as Twitter) are the representative information communication networks during the Web 2.0 era, which have gained remarkable popularity. Weibo has become a popular platform for information dissemination in online social networks due to its large number of users. In this study, a microblog information dissemination model is presented. Related concepts are introduced and analyzed based on the dynamic model of infectious disease, and new influencing factors are proposed to improve the susceptible-infective-removal (SIR) information dissemination model. Correlation analysis is conducted on the existing information dissemination risk and the rumor dissemination model of microblog. In this study, web hyper is used to model rumor dissemination. Finally, the experimental results illustrate the effectiveness of the method in reducing the rumor dissemination of microblogs.

Detection of flaw in steel anchor-concrete composite using high-frequency wave characteristics

  • Rao, Rajanikant;Sasmal, Saptarshi
    • Steel and Composite Structures
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    • 제31권4호
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    • pp.341-359
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    • 2019
  • Non-monolithic concrete structural connections are commonly used both in new constructions and retrofitted structures where anchors are used for connections. Often, flaws are present in anchor system due to poor workmanship and deterioration; and methods available to check the quality of the composite system afterward are very limited. In case of presence of flaw, load transfer mechanism inside the anchor system is severely disturbed, and the load carrying capacity drops drastically. This raises the question of safety of the entire structural system. The present study proposes a wave propagation technique to assess the integrity of the anchor system. A chemical anchor (embedded in concrete) composite system comprising of three materials viz., steel (anchor), polymer (adhesive) and concrete (base) is considered for carrying out the wave propagation studies. Piezoelectric transducers (PZTs) affixed to the anchor head is used for actuation and the PZTs affixed to the surrounding concrete surface of the concrete-anchor system are used for sensing the propagated wave through the anchor interface to concrete. Experimentally validated finite element model is used to investigate three types of composite chemical anchor systems. Studies on the influence of geometry, material properties of the medium and their distribution, and the flaw types on the wave signals are carried out. Temporal energy of through time domain differentiation is found as a promising technique for identifying the flaws in the multi-layered composite system. The present study shows a unique procedure for monitoring of inaccessible but crucial locations of structures by using wave signals without baseline information.

SEIR 모형을 이용한 전염병 모형 예측 연구 (A study of epidemic model using SEIR model)

  • 도미진;김종태;최보승
    • Journal of the Korean Data and Information Science Society
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    • 제28권2호
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    • pp.297-307
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    • 2017
  • 질병 확산 모형은 질병의 확산 과정을 모형화 함으로써 질병이 발생하고 퍼지는 시간 내에서 통제하기 위하여 활용하고자 하는 모형이다. 본 연구에서는 질병 확산 모형의 가장 대표적인 SIR 모형에 기본적인 확장 접근을 하여 접촉군 (exposed)이라는 단계를 추가한 SEIR 모형을 이용하여 모형 구축을 하였다. 이 모형은 감염 대상군 (susceptible)의 사람들이 질병에 노출 된 잠복기를 거쳐 일정 시간이 경과한 후 감염되어 감염군 (infected)으로 이동한 후 다시 회복군 (removed)으로 이동하는 모형이다. 이와 같이 질병에 감염된 후 감염력이 생기는 잠복기가 있는 경우에 연구에 활용될 수 있다. 본 연구에서는 2015년 국내에서 발생한 메르스 코로나바이러스 (Middle East respiratory syndrome coronavirus; MERS CoV)에 의한 호흡기 감염증 자료를 수집하였다. 질병의 확산 과정이 결정적이 아닌 확률적인 흐름을 따른다고 가정하여 포아송 확률과정을 따른다고 보고 확률적 화학반응 모형을 이용하여 모형을 구축하였다. 모형을 구현하기 위해서 SEIR 모형의 세 모수인 질병에 노출된 정도를 나타내는 접촉률 (exposed rate), 질병의 감염 정도를 나타내는 감염률 (transmission rate), 질병의 회복정도를 나타내는 회복률 (recovery rate)를 추정함으로써, SEIR 모형에 적합하고 전염병 확산에 대한 예측을 수행하였다. 또한 접촉군이 정확하게 관찰되지 않을 부분을 보완하기 위하여 접촉군을 생성하는 과정을 전체 모형 구축 과정에 추가하였다.

Area-to-Area Poisson Kriging and Spatial Bayesian Analysis in Mapping of Gastric Cancer Incidence in Iran

  • Asmarian, Naeimehossadat;Jafari-Koshki, Tohid;Soleimani, Ali;Ayatollahi, Seyyed Mohammad Taghi
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권10호
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    • pp.4587-4590
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    • 2016
  • Background: In many countries gastric cancer has the highest incidence among the gastrointestinal cancers and is the second most common cancer in Iran. The aim of this study was to identify and map high risk gastric cancer regions at the county-level in Iran. Methods: In this study we analyzed gastric cancer data for Iran in the years 2003-2010. Area-to-area Poisson kriging and Besag, York and Mollie (BYM) spatial models were applied to smoothing the standardized incidence ratios of gastric cancer for the 373 counties surveyed in this study. The two methods were compared in term of accuracy and precision in identifying high risk regions. Result: The highest smoothed standardized incidence rate (SIR) according to area-to-area Poisson kriging was in Meshkinshahr county in Ardabil province in north-western Iran (2.4,SD=0.05), while the highest smoothed standardized incidence rate (SIR) according to the BYM model was in Ardabil, the capital of that province (2.9,SD=0.09). Conclusion: Both methods of mapping, ATA Poisson kriging and BYM, showed the gastric cancer incidence rate to be highest in north and north-west Iran. However, area-to-area Poisson kriging was more precise than the BYM model and required less smoothing. According to the results obtained, preventive measures and treatment programs should be focused on particular counties of Iran.

Genomic approaches for the understanding of aging in model organisms

  • Park, Sang-Kyu
    • BMB Reports
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    • 제44권5호
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    • pp.291-297
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    • 2011
  • Aging is one of the most complicated biological processes in all species. A number of different model organisms from yeast to monkeys have been studied to understand the aging process. Until recently, many different age-related genes and age-regulating cellular pathways, such as insulin/IGF-1-like signal, mitochondrial dysfunction, Sir2 pathway, have been identified through classical genetic studies. Parallel to genetic approaches, genome-wide approaches have provided valuable insights for the understanding of molecular mechanisms occurring during aging. Gene expression profiling analysis can measure the transcriptional alteration of multiple genes in a genome simultaneously and is widely used to elucidate the mechanisms of complex biological pathways. Here, current global gene expression profiling studies on normal aging and age-related genetic/environmental interventions in widely-used model organisms are briefly reviewed.

Remediated Food in Media Revised model of Lévi-Strauss' Culinary Triangle

  • Jong Sir, Oh
    • International Journal of Advanced Culture Technology
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    • 제11권1호
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    • pp.181-191
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    • 2023
  • This study suggests a revised model of Lévi-Strauss' culinary triangle, which is frequently cited in food-related articles. To scrutinize how the media shares content about food and to remediate food discourse, this study conducted a focus group interview and targeted food program viewers and classified discoursal elements or nodes by Nvivo qualitative tools. In the process of classification, it found what seems to be hard to explain in the current food culture with Lévi-Strauss' culinary triangle, even if it still depicts appropriately, in the post-modern era implied complexity. Then, it arranged obtained discoursal nodes and analyzed the relationship between them. Interestingly, food in media plays as an important role beyond food itself, such as it can trigger memories, create social divides, play a role in economic invigoration, etc. Consequently, this paper suggests the revised culinary triangle model expanded from Lévi-Strauss' in which traces the molding process of food remediation with discoursal nodes in stages.

시뮬레이션을 이용한 생물테러 발생에 따른 피해예측에 관한 연구 ­천연두를 중심으로­ (A Study on the Demage forecast of Biological Terrorism ­Focused on Smallpox­)

  • 김영훈;박정화;김태현;문성암
    • 한국국방경영분석학회지
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    • 제29권2호
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    • pp.26-44
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    • 2003
  • This study Is to forecast the damage of smallpox as a biological weapon and to measure the effect of potential responses (quarantine, vaccination and cure) to the spread of smallpox infection when a smallpox bioterrorism attack occurs. We designed the smallpox spreading simulation model through the literature study on a basis of some existing infectious disease models such as SIR, SEIR model by using Vensim program. In order to evaluate the performance of responses to smallpox, we measure the total infection population, infection sustaining duration, average infection rate and the infection spreading behavior of the smallpox. This study can help those who are related to the bioterrorism forecast the present and possible demage, and take more effective actions for minimizing the damage by smallpox bioterrorism.

자동창고의 저장 및 불출요구의 대기시간에 관한 연구 (Expected Waiting Times for Storage and Retrieval Requests in Automated Storage and Retrieval Systems)

  • 조면식
    • 대한산업공학회지
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    • 제30권4호
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    • pp.306-316
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    • 2004
  • We present a closed form approximate analytical model to estimate the expected waiting times for the storage and retrieval requests of an automated storage/retrieval (AS/R) system, assuming that the storage/retrieval (S/R) machine idles either at the rack or at the input/output point. The expected waiting times (and the associated mean queue lengths) can play an important role to decide whether the performance of a stable AS/R system is actually acceptable, to determine buffer size (or length) of the input conveyor, and to compute the number of the rack openings which is required to hold the loads which are requested by processing machines but waiting in the rack to be retrieved by the SIR machine. This model can be effectively used in the early design stage of an AS/R system.

Moringa oleifera Prolongs Lifespan via DAF-16/FOXO Transcriptional Factor in Caenorhabditis elegans

  • Im, Jun Sang;Lee, Ha Na;Oh, Jong Woo;Yoon, Young Jin;Park, Jin Suck;Park, Ji Won;Kim, Jung Hoon;Kim, Yong Sung;Cha, Dong Seok;Jeon, Hoon
    • Natural Product Sciences
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    • 제22권3호
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    • pp.201-208
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    • 2016
  • Here in this study, we investigated the lifespan-extending effect and underlying mechanism of methanolic extract of Moringa olelifa leaves (MML) using Caenorhabditis elegans (C. elegans) model system. To define the longevity properties of MML we conducted lifespan assay and MML showed significant increase in lifespan under normal culture condition. In addition, MML elevated stress tolerance of C. elegans to endure against thermal, oxidative and osmotic stress conditions. Our data also revealed that increased activities of antioxidant enzymes and expressions of stress resistance proteins were attributed to MML-mediated enhanced stress resistance. We further investigated the involvement of MML on the aging-related factors such as growth, food intake, fertility, and motility. Interestingly, MML significantly reduced growth and egg-laying, suggesting these factors were closely linked with MML-mediated longevity. We also observed the movement of aged worms to estimate the effects of MML on the health span. Herein, MML efficiently elevated motility of aged worms, indicating MML may affect health span as well as lifespan. Our genetic analysis using knockout mutants showed that lifespan-extension activity of MML was interconnected with several genes such as skn-1, sir-2.1, daf-2, age-1 and daf-16. Based on these results, we could conclude that MML prolongs the lifespan of worms via activation of SKN-1 and SIR-2.1 and inhibition of insulin/IGF pathway, followed by DAF-16 activation.

Lateral load sharing and response of piled raft foundation in cohesionless medium: An experimental approach

  • Dinesh Kumar Malviya;Manojit Samanta
    • Geomechanics and Engineering
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    • 제38권2호
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    • pp.139-155
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    • 2024
  • The piled raft foundations are subjected to lateral loading under the action of wind and earthquake loads. Their bearing behavior and flexural responses under these loadings are of prime concern for researchers and practitioners. The insufficient experimental studies on piled rafts subjected to lateral loading lead to a limited understanding of this foundation system. Lateral load sharing between pile and raft in a laterally loaded piled raft is scarce in literature. In the present study, lateral load-displacement, load sharing, bending moment distribution, and raft inclinations of the piled raft foundations have been discussed through an instrumented scaled down model test in 1 g condition. The contribution of raft in a laterally loaded piled raft has been evaluated from the responses of pile group and piled raft foundations attributing a variety of influential system parameters such as pile spacing, slenderness ratio, group area ratio, and raft embedment. The study shows that the raft contributes 28-49% to the overall lateral capacity of the piled raft foundation. The results show that the front pile experiences 20-66% higher bending moments in comparison to the back pile under different conditions in the pile group and piled raft. The piles in the piled raft exhibit lower bending moments in the range of 45-50% as compared to piles in the pile group. The raft inclination in the piled raft is 30-70% less as compared to the pile group foundation. The lateral load-displacement and bending moment distribution in piles of the single pile, pile group, and piled raft has been presented to compare their bearing behavior and flexural responses subjected to lateral loading conditions. This study provides substantial technical aid for the understanding of piled rafts in onshore and offshore structures to withstand lateral loadings, such as those induced by wind and earthquake loads.