• Title/Summary/Keyword: Underwood

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Development of ViscoElastoPlastic Continuum Damage (VEPCD) Model for Response Prediction of HMAs under Tensile Loading (인장하중을 받는 아스팔트 혼합물의 점탄소성 모형의 개발)

  • Underwood, B. Shane;Kim, Y. Richard;Seo, Youngguk;Lee, Kwang-Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.1D
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    • pp.45-55
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    • 2008
  • The objective of this research was to develop a VEPCD (ViscoElastoPlastic Continuum Damage) Model which is used to predict the behavior of asphalt concrete under various loading and temperature conditions. This paper presents the VEPCD model formulated in a tension mode and its validation using four hot mix asphalt (HMA) mixtures: dense-graded HMA, SBS, CR-TB, and Terpolymer. Modelling approaches consist of two components: the ViscoElastic Continuum Damage (VECD) mechanics and the ViscoPlastic (VP) theory. The VECD model was to describe the time-dependent behavior of HMA with growing damage. The irrecoverable (whether time-dependent or independent) strain has been described by the VP model. Based on the strain decomposition principle, these two models are integrated to form the VEPCD model. For validating the VEPCD model, two types of laboratory tests were performed: 1) a constant crosshead strain rate tension test, 2) a fatigue test with randomly selected load levels and frequencies.

Analysis of the Hebei Spirit Oil Spill Incident and its Aftermath (허베이 스피리트호 유류오염사고와 그 영향에 관한 분석)

  • Lee, Juhyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.5
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    • pp.455-461
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    • 2017
  • The Hebei Spirit oil spill incident occurred in December 7, 2007 and caused approximately $12,547k{\ell}$ of crude oil spillage along 370km off the west coast of Korea. Due to the astronomical and irrecoverable damage to the marine ecosystems and the overall living standards of the residents, the oil spill incident has been notoriously named as the "worst oil spill incident" occurred in Korea. Nevertheless, though almost a decade has passed since the tragic incident in Korea, it appears that compensation and recovery efforts seem not close to satisfaction and the local residents are still struggling with various negative impacts incurred by the incident because of critical cleavage among the interests of the relevant parties to the incident. In this paper, the analysis of Hebei Spirit oil spill incident regarding two aspects was carried out; First, meticulously analyze the practical and statistical data of the incident to precisely examine the fundamental causes for its occurrence to further prevent the reoccurrence of such disastrous incident; and the second, comprehensively inspect reasons for the protracted and inefficient damage recovery and victim-oriented compensation. To be specific, this study observed the levels of compensation against damages from the incident, and the adequacy of it in terms of ultimately and inclusively addressing financial, social and ecological aspects based primarily upon the legal verdicts, and statistical and empirical surveys.

Consent for using human biological material in research: based on the revised Bioethics and Safety Act (인체유래물연구에 대한 동의 소고(小考) - 개정 생명윤리법 제42조의2를 계기로 -)

  • Lee, Dongjin;Lee, Sun Goo
    • The Korean Society of Law and Medicine
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    • v.20 no.2
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    • pp.111-140
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    • 2019
  • The Bioethics and Safety Act provides a set of rules to regulate biobanks and research activities using human biological material, but the law seems to be defective in several folds. The law requires that, prior to collection or use of human biological materials, researchers should obtain the informed consent of the donors, but the law does not obligate biobanks to do so. Even in cases where the law requires informed consent, the ordinance of the Ministry of Health and Welfare allows open (or blanket) consent. In addition, a new article in the Act, Article 42-2 which will take effect from October 24, 2019, allows medical institutions to provide biobanks with remaining biospecimens collected in the course of diagnosis and treatment, unless the donors express their intent to opt-out, without obtaining specific consent from them. Given the need to protect the autonomy of donors and the unique characteristics of biobanks and research activities that use human biological materials, this paper concludes that such open consent-based law may not be suitable to protect the autonomy of the donors and that the broad consent requirement may be a desirable policy option. The paper acknowledges that the international community has long questioned whether broad consent (as well as open consent) is an effective choice to regulate the use of human biological materials. The paper stresses that the baseline requirement in designing the law is that the secondary use of human biological materials should be based on informed consent of the donors; the core value of the law should be a governance structure that promotes transparency and protects donor participation.

Spatial dispersion of aggregate in concrete a computer simulation study

  • Hu, Jing;Chen, Huisu;Stroeven, Piet
    • Computers and Concrete
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    • v.3 no.5
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    • pp.301-312
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    • 2006
  • Experimental research revealed that the spatial dispersion of aggregate grains exerts pronounced influences on the mechanical and durability properties of concrete. Therefore, insight into this phenomenon is of paramount importance. Experimental approaches do not provide direct access to three-dimensional spacing information in concrete, however. Contrarily, simulation approaches are mostly deficient in generating packing systems of aggregate grains with sufficient density. This paper therefore employs a dynamic simulation system (with the acronym SPACE), allowing the generation of dense random packing of grains, representative for concrete aggregates. This paper studies by means of SPACE packing structures of aggregates with a Fuller type of size distribution, generally accepted as a suitable approximation for actual aggregate systems. Mean free spacing $\bar{\lambda}$, mean nearest neighbour distance (NND) between grain centres $\bar{\Delta}_3$, and the probability density function of ${\Delta}_3$ are used to characterize the spatial dispersion of aggregate grains in model concretes. Influences on these spacing parameters are studied of volume fraction and the size range of aggregate grains. The values of these descriptors are estimated by means of stereological tools, whereupon the calculation results are compared with measurements. The simulation results indicate that the size range of aggregate grains has a more pronounced influence on the spacing parameters than exerted by the volume fraction of aggregate. At relatively high volume density of aggregates, as met in the present cases, theoretical and experimental values are found quite similar. The mean free spacing is known to be independent of the actual dispersion characteristics (Underwood 1968); it is a structural parameter governed by material composition. Moreover, scatter of the mean free spacing among the serial sections of the model concrete in the simulation study is relatively small, demonstrating the sample size to be representative for composition homogeneity of aggregate grains. The distribution of ${\Delta}_3$ observed in this study is markedly skew, indicating a concentration of relatively small values of ${\Delta}_3$. The estimate of the size of the representative volume element (RVE) for configuration homogeneity based on NND exceeds by one order of magnitude the estimate for structure-insensitive properties. This is in accordance with predictions of Brown (1965) for composition and configuration homogeneity (corresponding to structure-insensitive and structure-sensitive properties) of conglomerates.

Nitric Oxide Delivery using Nanostructures and Its Biomedical Applications (나노 구조체를 이용한 산화질소 전달체에 대한 연구 및 바이오메디컬 응용)

  • Choi, Yunseo;Jeong, Hyejoong;Park, Kyungtae;Hong, Jinkee
    • Korean Chemical Engineering Research
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    • v.57 no.3
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    • pp.305-312
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    • 2019
  • The discovery of nitric oxide (NO) as a major signaling molecule in a number of pathophysiological processes - vasodilation, immune response, platelet aggregation, wound repair, and cancer biology - has led to the development of various exogeneous NO delivery systems. However, the development of ideal delivery system for human body application is still left as a challenge due to its high reactivity and short half-life in physiological condition. In this article, an overview of several nano-structures as potential NO delivery system will be presented, along with their recent research results and biomedical applications. Nano-size delivery system has immense advantages compared to others due to its high surface-to-volume ratio and capability for surface modification; thus, it has been proven to be effective in delivering nitric oxide with enhanced performance. Through this novel nano-structure delivery system, we are expecting to achieve sustained release of nitric oxide within adequate range of concentration, which ensures desired drug effects at the target site. Among different nano-structures, in particular, nanoparticle, microemulsion and nanofilm will be reviewed and compared to each other in respect of nitric oxide release profile. The proposed nano-structures for exogeneous NO delivery have a biological significance in that it can be further utilized in diverse biomedical fields as a highly promising therapeutic method.

Analysis of the Views of Nature of Elementary and Secondary School Students and Teachers and Its Implications for Science Education : Focusing on the Korean Traditional Views of Nature (초·중등학교 학생과 교사의 자연관 분석 및 과학교육에 주는 함의 : 한국의 전통적 자연관을 중심으로)

  • Lee, Yumi;Oh, Jun-Young;Son, Yeon-A
    • Journal of the Korean Society of Earth Science Education
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    • v.12 no.3
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    • pp.208-223
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    • 2019
  • In this study, it was analyzed first the views of nature of elementary and middle school students using the analysis framework of the views of nature that reflects the results of the literature analysis on the traditional views of nature that Koreans traditionally have. Next, it was analyzed characteristics of the views of nature which elementary and secondary school teachers. Finally, it was discussed the implications of the results of analysis of students' and teachers' views on science education in elementary and secondary schools. For this purpose, the framework for analysis the views of nature was reconstructed by combining the characteristics of Korean's traditional views of nature (Lee & Son, 2017) with the framework developed by Cobern and his colleagues (Cobern, Gibson, & Underwood, 1995). And in order to analyze in depth how students and teachers perceive nature, each question was asked to write a reason why they thought about their responses. According to the study, students and teachers respected nature and viewed it as a living creature, and had the view that nature was cyclical and that humans and nature interacted with each other. And they also had a traditional Korean view of nature that they consider naturalness important and nature is beautiful. It can be said that this is different from the view of Western modern science which perceives the world as a material and see nature with the view of linear time. Therefore, Korea's traditional views of natures, which students and teachers have, can be a conflict with the view of modern science in science class. Therefore, the science teaching strategy for students and teachers with different natural views will require consideration of the individual's understanding of nature and lesson strategies related to it. And it is also necessary that science textbook and science class cultures need to actively interact with teachers and students, and between students to share and understand each other's view of nature, and create a science class culture that considers the values students have and views on nature.

Policy suggestions for active reporting of medical professionals for early detection of child abuse (아동학대의 조기발견을 위한 제도적 개선 방안: 「아동학대범죄의 처벌 등에 대한 특례법」이 정한 의료인에 의한 신고를 중심으로)

  • Bae, Seung Min;Lee, Sun Goo
    • The Korean Society of Law and Medicine
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    • v.18 no.1
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    • pp.143-169
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    • 2017
  • The Act on Special Cases Concerning the Punishment, etc. of Child Abuse Crimes intends to encourage reporting and punishment of child abuse by using the concept of 'crime' in child abuse cases. Article 10 of the Act imposes duty to report child abuse on a number of different professions, including medical professionals. Currently, more than 80% of child abuse cases occur among family members and the detection rate of child abuse is as low as 0.5% in Korea. On the other hand, medical professionals can identify child abuse relatively clearly with specific medical opinions. Therefore, it is necessary that medical professions are informed of this duty and does not bear disincentive from reporting. This paper makes policy suggestions in this regard. First, it is necessary that medical students and medical professionals receive regular education about the obligation to report child abuse. Education should include details of the reporting duty, as well as the fact that there is legal obligation to report even if the child abuse is "suspicious", not certain. Second, it is imperative to establish and implement protective programs for medical professionals who report child abuse. The current law provides a rough framework for protection of people who report child abuse, but it is necessary to produce detailed guidelines that are applicable in the context of medical setting. Education for medical students and medical professionals should include the contents of these guidelines, so that they do not hesitate reporting because they fear the aftermath of reporting. Third, it is highly recommended that physicians use the national Baby/Infant Health Checkup Program as an opportunity to detect child abuse. In Korea, the Baby/Infant Health Checkup Program provides physicians to periodically monitor health condition of all babies and children until the age of 71 months. In order to utilize this program for early detection of child abuse, it is imperative that the bBaby/Infant Health Checkup Program is modified to involve child abuse experts and medical professionals who participate in the program are educated about child abuse.

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Factors Influencing Sexuality Knowledge and Gender Sensitivity During Adolescents and Early Adulthoods (청소년기 및 초기 성인기의 성지식과 성인지 감수성에 영향을 미치는 요인)

  • Hae Su Na;Sun Goo Lee;Kang Min Baek;Woo Young Im;Seung-Gul Kang;Seong-Jin Cho;Kyoung-Sae Na;Jae Myeong Kang;Seo-Eun Cho;Seung Min Bae
    • Korean Journal of Psychosomatic Medicine
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    • v.31 no.1
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    • pp.25-32
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    • 2023
  • Objectives : This study investigated the level of sexuality knowledge and gender sensitivity and factors influencing on them among Korean high school and college students. Methods : 129 questionnaires from high school and college students with consent forms, collected from July to December of 2022, were analyzed. After identification of participants' gender, age, major, their report of the practicality of sex education, and their experience of violence or sexual assaults, participants' level of sexuality knowledge and gender sensitivity were compared. Results : Females showed higher gender sensitivity, regardless of age and group (p=0.004). The early adulthood group (≥19 years old) showed higher sexuality knowledge and gender sensitivity, compared to those adolescents (<19 years old). Among college students, those who majored in health science were identified with higher sexuality knowledge and gender sensitivity, compared to non-health science major students(p<0.001; p=0.005). Conclusions : This study revealed the significant differences in sexuality knowledge and gender sensitivity according to sex, age, and majors in adolescents and early adults. Therefore, it seems to be necessary to consider the differences in sexuality knowledge and gender sensitivity among age, sex, and majors when establishing public policy or legislation for sex crimes, including digital sex crimes.

New Insights on Mobile Location-based Services(LBS): Leading Factors to the Use of Services and Privacy Paradox (모바일 위치기반서비스(LBS) 관련한 새로운 견해: 서비스사용으로 이끄는 요인들과 사생활염려의 모순)

  • Cheon, Eunyoung;Park, Yong-Tae
    • Journal of Intelligence and Information Systems
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    • v.23 no.4
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    • pp.33-56
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    • 2017
  • As Internet usage is becoming more common worldwide and smartphone become necessity in daily life, technologies and applications related to mobile Internet are developing rapidly. The results of the Internet usage patterns of consumers around the world imply that there are many potential new business opportunities for mobile Internet technologies and applications. The location-based service (LBS) is a service based on the location information of the mobile device. LBS has recently gotten much attention among many mobile applications and various LBSs are rapidly developing in numerous categories. However, even with the development of LBS related technologies and services, there is still a lack of empirical research on the intention to use LBS. The application of previous researches is limited because they focused on the effect of one particular factor and had not shown the direct relationship on the intention to use LBS. Therefore, this study presents a research model of factors that affect the intention to use and actual use of LBS whose market is expected to grow rapidly, and tested it by conducting a questionnaire survey of 330 users. The results of data analysis showed that service customization, service quality, and personal innovativeness have a positive effect on the intention to use LBS and the intention to use LBS has a positive effect on the actual use of LBS. These results implies that LBS providers can enhance the user's intention to use LBS by offering service customization through the provision of various LBSs based on users' needs, improving information service qualities such as accuracy, timeliness, sensitivity, and reliability, and encouraging personal innovativeness. However, privacy concerns in the context of LBS are not significantly affected by service customization and personal innovativeness and privacy concerns do not significantly affect the intention to use LBS. In fact, the information related to users' location collected by LBS is less sensitive when compared with the information that is used to perform financial transactions. Therefore, such outcomes on privacy concern are revealed. In addition, the advantages of using LBS are more important than the sensitivity of privacy protection to the users who use LBS than to the users who use information systems such as electronic commerce that involves financial transactions. Therefore, LBS are recommended to be treated differently from other information systems. This study is significant in the theoretical point of contribution that it proposed factors affecting the intention to use LBS in a multi-faceted perspective, proved the proposed research model empirically, brought new insights on LBS, and broadens understanding of the intention to use and actual use of LBS. Also, the empirical results of the customization of LBS affecting the user's intention to use the LBS suggest that the provision of customized LBS services based on the usage data analysis through utilizing technologies such as artificial intelligence can enhance the user's intention to use. In a practical point of view, the results of this study are expected to help LBS providers to develop a competitive strategy for responding to LBS users effectively and lead to the LBS market grows. We expect that there will be differences in using LBSs depending on some factors such as types of LBS, whether it is free of charge or not, privacy policies related to LBS, the levels of reliability related application and technology, the frequency of use, etc. Therefore, if we can make comparative studies with those factors, it will contribute to the development of the research areas of LBS. We hope this study can inspire many researchers and initiate many great researches in LBS fields.