• Steel and Composite Structures
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• 제52권2호
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• pp.199-215
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• 2024

The Caynarachi Bridge is a 130 m long posttensioned steel-concrete composite bridge built in Peru. The structural performance of this bridge under construction loads is reviewed in this paper using numerical simulation. Hence, a numerical model using shell finite elements to trace its deformational behavior at service conditions is proposed. The geometry and boundary conditions of the superstructure are updated according to the construction schedule. Firstly, the adequacy of the proposed model is validated with the field measurements obtained from the static truck load test. Secondly, the study of other scenarios less explored in research are performed to investigate the effect of some variables on bridge performance such as time effects, sequence of execution of concrete slabs and type of supports conditions at the abutments. The obtained results show that the original sequence of execution of the superstructure better behaves mechanically in relation to the other studied scenarios, yielding smaller stresses at critical cross sections with staging. It is also demonstrated that an improper slab staging may lead to more critical stresses at the studied cross sections and that casting the concrete slab at the negative moment regions first can lead to an optimal design. Also, the long-term displacements can be accurately predicted using an equivalent composite resistance cross section defined by a steel to concrete modulus ratio equal to three. This article gives some insights into the potential shortcomings or advantages of the original design through high-fidelity finite element simulations and reinforces the understating of posttensioned composite bridges with staging.

• 천문학회보
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• 제41권1호
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• pp.38.2-38.2
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• 2016

The mapping of dark matter clustering from real to redshift spaces introduces the anisotropic property to the measured density power spectrum in redshift space, known as the Redshift Space Distortion (hereafter RSD) effect. The mapping formula is intrinsically non-linear, which is complicated by the higher order polynomials due to the indefinite cross correlations between the density and velocity fields, and the Finger-of-God (hereafter FoG) effect due to the randomness of the peculiar velocity field. Furthermore, the rigorous test of this mapping formula is contaminated by the unknown non-linearity of the density and velocity fields, including their auto- and cross-correlations, for calculating which our theoretical calculation breaks down beyond some scales. Whilst the full higher order polynomials remains unknown, the other systematics can be controlled consistently within the same order truncation in the expansion of the mapping formula, as shown in this paper. The systematic due to the unknown non-linear density and velocity fields is removed by separately measuring all terms in the expansion using simulations. The uncertainty caused by the velocity randomness is controlled by splitting the FoG term into two pieces, 1) the non-local FoG term being independent of the separation vector between two different points, and 2) the local FoG term appearing as an indefinite polynomials which is expanded in the same order as all other perturbative polynomials. Using 100 realizations of simulations, we find that the best fitted non-local FoG function is Gaussian, with only one scale-independent free parameter, and that our new mapping formulation accurately reproduces the observed power spectrum in redshift space at the smallest scales by far, up to k ~ 0.3 h/Mpc, considering the resolution of future experiments.

• KDI Journal of Economic Policy
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• 제36권2호
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• pp.65-101
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• 2014

본 연구에서는 이자율 변수에 적절한 확률과정을 부여하고 이를 가격함수에 직접 대입한 뒤 최종적으로 자산가격 PDE를 도출하는 재무모형을 이용하여 우리나라 기대인플레이션을 추정하고 그 특성을 살펴보고자 한다. 우리나라의 기대인플레이션은 글로벌 금융위기 이전에는 4%를 상회하는 높은 수준을 보였으나 2008년 후반을 기점으로 하향 안정화되는 모습을 시현했다. 또한 수익률곡선에서 도출된 기대인플레이션과 서베이 등을 통해 실제로 자료의 입수가 가능한 기대인플레이션을 이용하여 경제주체의 기대인플레이션 형성에 체계적인 편의가 존재하지 않고(불편성), 기대형성에 활용 가능한 모든 정보가 반영되었는지(효율성)를 기준으로 합리성을 평가한 결과, 분석에 이용된 모든 기대인플레이션에서 효율성은 기각되나 기대편의는 발생하지 않는 것으로 나타났다. 한편, 실제인플레이션과 기대인플레이션 간의 Granger 인과관계 검정 결과, 대체로 컨센서스 및 BOK 전문가 기대인플레이션은 상대적으로 장기의 실제인플레이션과, 이자율모형에서 도출된 기대인플레이션은 단기의 실제인플레이션과 상호 인과관계가 발생하는 것으로 분석되었다. 이러한 결과는 각각의 인플레이션 지표들이 내포하는 인플레이션의 정보가 상이하다는 것을 방증하고 있다. 이는 중앙은행이 하나의 인플레이션 지표보다는 다양한 지표들을 균형 있는 시각으로 관찰하는 것이 필요함을 시사한다.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.583-592
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• 2011

The radiological characteristics for waste classification were assessed for neutron-activated decommissioning wastes from a CANDU reactor. The MCNP/ORIGEN2 code system was used for the source term analysis. The neutron flux and activation cross-section library for each structural component generated by MCNP simulation were used in the radionuclide buildup calculation in ORIGEN2. The specific activities of the relevant radionuclides in the activated metal waste were compared with the specified limits of the specific activities listed in the Korean standard and 10 CFR 61. The time-average full-core model of Wolsong Unit 1 was used as the neutron source for activation of in-core and ex-core structural components. The approximated levels of the neutron flux and cross-section, irradiated fuel composition, and a geometry simplification revealing good reliability in a previous study were used in the source term calculation as well. The results revealed the radioactivity, decay heat, hazard index, mass, and solid volume for the activated decommissioning waste to be $1.04{\times}10^{16}$ Bq, $2.09{\times}10^3$ W, $5.31{\times}10^{14}\;m^3$-water, $4.69{\times}10^5$ kg, and $7.38{\times}10^1\;m^3$, respectively. According to both Korean and US standards, the activated waste of the pressure tubes, calandria tubes, reactivity devices, and reactivity device supporters was greater than Class C, which should be disposed of in a deep geological disposal repository, whereas the side structural components were classified as low- and intermediate-level waste, which can be disposed of in a land disposal repository. Finally, this study confirmed that, regardless of the cooling time of the waste, 15% of the decommissioning waste cannot be disposed of in a land disposal repository. It is expected that the source terms and waste classification evaluated through this study can be widely used to establish a decommissioning/disposal strategy and fuel cycle analysis for CANDU reactors.

• 비교문화연구
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• 제27권
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• pp.471-496
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• 2012

Since Takeo Toi's discussion in The Anatomy of Dependence (1973), the concept of amae has generated considerable interest in the fields of psychology, anthropology, communication and other fields. However, there have been few agreements on the definition and functions of amae (Behrens, 2004). Furthermore, it has rarely drawn interest from linguists in general and has rarely been discussed in the context of social interaction. This study aims to examine the concept of amae in Japanese and the corresponding phenomena in Korean, and attempts to explore the similarities and differences between them. The prototype of the amae relationship is the mother-infant relationship (Doi,1973). Even an adult can assume the role of a baby, showing his or her need for dependence on others and expecting to be accepted. It turns out that amae-like phenomena frequently occur in everyday life in Korea as well (Lee, 1982). There is no single term for the concept, but it can be translated in many different ways in Korean, for example, aykyo, ayang, ungsek, erikwang, etc. It can have either positive or negative connotations depending on the situation. It seems that the psychological system that causes dependent behaviors such as ungsek in Korea is cheong, one of the key terms characterizing the Korean culture. Cheong, like amae, starts in the mother-infant relationship extending to familial and to other relationships. A corpus-based analysis shows that cheong is conceptualized as gluing people together, growing over time, and also potentially fatal because it assumes illogical, uncalculated, and personal relationships. In conclusion, unlike some Japanese scholars' claim that amae is the Japanese concept that exists only in Japan, it seems that similar phenomena do exist in Korea as well, but that Korean has no single term corresponding to amae in Japanese. It seems that cheong can be posited in Korean as the inner emotional system that makes amae-like behaviors possible, and that there is not single term, but many, designating the behaviors, possibly because the behaviors have a negative connotation and are not encouraged in Korean society.

• 한국해양공학회지
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• 제25권4호
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• pp.59-65
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• 2011

In structural health monitoring (SHM) using electro-mechanical impedance signatures, it is a critical issue for extremely large structures to extract the best damage diagnosis results, while minimizing unknown environmental effects, including temperature, humidity, and acoustic vibration. If the impedance signatures fluctuate because of these factors, these fluctuations should be eliminated because they might hide the characteristics of the host structural damages. This paper presents a long-term SHM technique under an unknown noisy environment for tidal current power plant structures. The obtained impedance signatures contained significant variations during the measurements, especially in the audio frequency range. To eliminate these variations, a continuous principal component analysis was applied, and the results were compared with the conventional approach using the RMSD (Root Mean Square Deviation) and CC (Cross-correlation Coefficient) damage indices. Finally, it was found that this approach could be effectively used for long-term SHM in noisy environments.

• 가정∙방문간호학회지
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• 제23권2호
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• pp.155-165
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• 2016

Purpose: The purpose of this study was to investigate factors influencing health workers' infection management behavior in long-term care facilities. Methods: A descriptive cross-sectional survey was conducted with 180 health workers who are employed in long-term care facilities. The data were collected from April, 25 until July, in 2016. Results: Infection management behavior positively correlated with the perceived importance of infection management (r=.77, p<.001), but role conflict negatively correlated with infection management behavior (r=.28, p<.001). The hierarchical regression model with general characteristics (first step) and perceived importance of infection management, work environment, and role conflict (second step) against infection management behavior was statistically significant (F=31.93, p<.001). This model could explain 62.8% of infection management behavior ($R^2=.62$, ${\Delta}R^2=.39$). Particularly, perceived importance of infection management was identified as factors influencing infection management behavior(${\beta}=.70$, p<.001). Conclusion: The findings of this study imply that systemic education about infection control and monitoring should be considered, so as to encourage proper infection management behaviors among health workers in long-term care facilities.

• 아태비즈니스연구
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• 제10권2호
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• pp.27-41
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• 2019

Following the methodology of Ben-Rephael, Kadan and Wohl (2015), this paper examines whether firm-level liquidity premium exists and whether the premium exhibits a long-term trend in the Korean stock market. The results show that over the whole sample period (1998-2018), a liquidity premium of 0.083% exists in the cross-section of stocks. Interestingly, the pricing of liquidity declines significantly over the sample period. Sub-period analysis indicates that liquidity is priced mainly in the first sub-period (1998-2004) with a significant monthly premium of 0.304%, while the pricing of liquidity becomes weaker or insignificant in the second (2005-2011) and the third (2012-2018) period. I also find that the significance of the liquidity premium in the first period is attributed to small stocks. To explore underlying reasons that might affect the decline in the liquidity premium, I decompose liquidity premium into the product of firm-level liquidity and the sensitivity of expected stock returns on liquidity. The results reveal that the long-term decline is explained by both an increase in firm-level liquidity and a decrease in the sensitivity of expected returns on liquidity.

• 전력전자학회논문지
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• 제26권3호
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• pp.183-191
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• 2021

A battery management system (BMS) provides some functions for ensuring safety and reliability that includes algorithms estimating battery states. Given the changes caused by various operating conditions, the state-of-health (SOH), which represents a figure of merit of the battery's ability to store and deliver energy, becomes challenging to estimate. Machine learning methods can be applied to perform accurate SOH estimation. In this study, we propose a Long-Term Recurrent Convolutional Network (LRCN) that combines the Convolutional Neural Network (CNN) and Long Short-term Memory (LSTM) to extract aging characteristics and learn temporal mechanisms. The dataset collected by the battery aging experiments of NASA PCoE is used to train models. The input dataset used part of the charging profile. The accuracy of the proposed model is compared with the CNN and LSTM models using the k-fold cross-validation technique. The proposed model achieves a low RMSE of 2.21%, which shows higher accuracy than others in SOH estimation.

• Journal of Hospice and Palliative Care
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• 제24권1호
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• pp.26-35
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• 2021

Purpose: The purpose of this study was to determine the effects of awareness of good death and end-of-life care attitudes on end-of-life care performance in long-term care hospital nurses. Methods: This study used a cross-sectional study design. The participants were 147 nurses working at six long-term care hospitals with more than 200 beds in B city, South Korea. Data were collected using self-reported questionnaires, and analyzed with descriptive statistics, the t-test, analysis of variance, Pearson correlation coefficients, and multiple stepwise regression analysis using IBM/SPSS 26.0 for Windows. Results: The participants' awareness of good death, end-of-life care attitudes, and end-of-life care performance were positively correlated. The factors affecting end-of-life care performance were age, education level, awareness of good death, and end-of-life care attitudes; these variables explained 19.0% of end-of-life care performance. Conclusion: In order to improve long term care hospital nurses' end-of-life care performance, continuing education and training should be provided regarding awareness of good death and end-of-life care attitudes.