• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.237-254
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• 2019

This paper presents an improved time series based damage detection approach with experimental verifications for detection, localization, and quantification of damage in shear-type structures under varying mass effects using output-only vibration data. The proposed method can be very effective for automated monitoring of buildings to develop proactive maintenance strategies. In this method, Auto-Regressive Moving Average models with eXogenous inputs (ARMAX) are built to represent the dynamic relationship of different sensor clusters. The damage features are extracted based on the relative difference of the ARMAX model coefficients to identify the existence, location and severity of damage of stiffness and mass separately. The results from a laboratory-scale shear type structure show that different damage scenarios are revealed successfully using the approach. At the end of this paper, the methodology limitations are also discussed, especially when simultaneous occurrence of mass and stiffness damage at multiple locations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4483-4501
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• 2020

Recent findings identified the scatter and shape of MFD (macroscopic fundamental diagram) is heavily influenced by the spatial distribution of link density in a road network. This implies that the concept of MFD can be utilized to divide a heterogeneous road network with different degrees of congestion into multiple homogeneous subnetworks. Considering the actual traffic data is usually incomplete and inaccurate while most traffic partition algorithms rely on the completeness of the data, we proposed a three-step partitioned algorithm called Iso-MB (Isoperimetric algorithm - Merging - Boundary adjustment) permitting of incompletely input data in this paper. The proposed algorithm was implemented and verified in a simulated urban transportation network. The existence of well-defined MFD in each subnetwork was revealed and discussed and the selection of stop parameter in the isoperimetric algorithm was explained and dissected. The effectiveness of the approach to the missing input data was also demonstrated and elaborated.

• 천문학회보
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• 제46권2호
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• pp.64.1-64.1
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• 2021

Accretion flows around black holes and neutron stars emit high energy radiation with varying spectral and timing properties. Observed timing variations, both short and long-term, point to the existence of a mechanism, dictated by the flow dynamics, and not by the stellar surface or magnetic fields, that is common in both. Spectral energy distributions of multiple sources indicate that the Comptonization process, the dominant mechanism for changing states in X-ray, takes place inside the flow that has similar physical properties in both the objects. In a series of observational and numerical studies, we enquire about the following: 1. Is there a steady state configuration for accreting matter around black holes that can explain spectral and timing properties? 2. Could a similar formalism explain spectral and timing properties of accretion around neutron stars? 3. Could there be a generalized flow configuration for accreting matter around such compact objects? Furthermore, we show that a unified spectral model can be constructed based on the generalized flow configuration, common to black holes and neutron stars.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.579-584
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• 2008

고속철도 차륜의 미소결함을 고속 고공간 분해 능으로 측정할 수 있는 새로운 비파괴검사법이 요구되고 있다. 본 연구는 종래의 스캔형 자기카메라를 개선하여, 다중증폭회로와 결함표시를 위한 펄스 발생기를 장착한 신호처리회로를 제안한다. 홀센서를 선형으로 배열하고, 배열의 직각방향으로 차륜이 정속으로 회전하게 하면, 차륜의 답면을 검사할 수 있다. 각각의 홀전압을 증폭하고, AD변환기를 통하여 $\mu$-processor에 의하여 시간에 따른 전압차, 즉 ${\partial}V_H/{\partial}t$를 연산한다. ${\partial}V_H/{\partial}t$가 결함의 존재를 의미하는 비교치보다 클 때 pulse 신호가 발생하여 결함을 지시한다. 휠 시험편을 이용하여 제안된 방법을 검증하였다.

• 한국실내디자인학회논문집
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• 제14권2호
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• pp.63-71
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• 2005

The dome structure has been treated in two layers among the techniques that have formed the space in Baroque architecture and the light used to be manipulated to create the openness of space and the fantasy of atmosphere. Such an expression technique has influenced on the expression of space in the architecture of New York Five in the 1960s to 1970s and the concept of multiple space embellished with various layers has appeared in the architectural concept of New York Five; meanwhile, the common meaning with the technique of double layers and the ways of phenomenal expressions that have recognized the existence of space in the Baroque period has been achieved through the light, immaterial organism. It means that the existing concept of light limited simply to the plane elements of brightness and darkness has been treated as a formative element that has defined and adjusted the visual expansion and reduction of the space Itself and special existence and has been used as an element of the media of spatial structure. In addition, these elements have been treated as another solution for the emotional aspects of space. Therefore, this study compares the plastic and formative meaning of the Baroque architecture with that of New York Five in terms of the relation between space and light and examines them; in doing so, it will give a clue to understand various and new space expression techniques to many architects and space designers who have led modern architecture.

• 한국식생활문화학회지
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• 제15권4호
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• pp.259-268
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• 2000

The purpose of this study was to describe the levels of market goods substitution of housework and find out the determinants on it in the domain of food among married female home-based workers. The data were collected from 169 married female home-based workers in Pusan and Kyungnam province, by self-administered questionnaires. Frequencies, percentiles, Cronbach's alpha, Pearson's correlations, and multiple regression were used to analyze the data. In the convenience foods, frozen foods had the highest substitution level, whereas prepared stew had the lowest. The substitution level of Korean traditional storage foods was the middle. And in dining-out service, the substitution level was mostly high: the level of delivery service was higher than that of dining-out. Compared to the previous research, these results showed that market goods substitution tended to increase, and its level in the domain of food will promote continually over time. The variables affecting the substitution level of convenience food were the number of family members, occupation, the existence of elderly/disabled person in the family, sex-role attitude, and weekly hours at home-based work. The substitution level of Korean traditional storage foods was influenced by sex-role attitude, occupation, education, monthly household income, and the existence of elderly/disabled person in the family. The significant variables affecting the substitution level of dining-out service were weekly hours at home-based work, the number of family members, occupation, monthly household income, education, and sex-role attitude.

• 한국통신학회논문지
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• 제33권11A호
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• pp.1013-1020
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• 2008

코그니티브 라디오(cognitive radio) 기술 중 같은 지역에서 코그니티브 사용자와 우선사용자가 주파수를 공유하여 사용하는 방법은 단위 지역 당 주파수 사용효율을 향상시킬 수 있는 중요한 기술로 인식되고 있다. 본 논문에서는 코그니티브 라디오 시스템이 우선사용자에게 간섭을 미치지 않으며 동일 지역에서 우선사용자와 주파수를 공유할 수 있는 직교 빔 형성 방법을 제안한다. 제안된 방법은 우선사용자의 채널상태정보(channel state information)로부터 얻어진 부공간에 직교하는 코그니티브 라디오 사용자를 위한 부공간을 형성함으로써 우선사용자에게 간섭을 주지 않으며 주파수를 공유할 수 있는 코그니티브 라디오 사용자를 위한 다중 빔을 생성한다. 그러고, 코그니티브 라디오 시스템의 합 용량을 증가시키기 위해 기회적 무선자원할당 기법을 적용하였다. 전산모의 실험을 통해 제안된 주파수 공유 방법이 우선사용자에게 간섭을 주지 않음을 보였고 코그니티브 라디오 기지국이 2개의 안테나를 사용할 경우 시스템 합용량이 일반 셀룰라 시스템의 빔 포밍을 적용한 결과와 유사하게 사용자 20명에서 최대 2.72bps/Hz를 얻을 수 있음을 확인하였다.

• 천문학논총
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• 제15권spc1호
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• pp.103-112
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• 2000

Symbiotic stars are known as binary systems of a giant with heavy mass loss and a white dwarf accompanied by an emission nebula. They often show bipolar nebulae, and are believed to form an accretion disk around the white dwarf component by attracting the slow but heavy stellar wind around the giant companion. However, the existence and physical properties of the accretion disk in these systems still remain controversial. Unique to the spectra of symbiotic stars is the existence of the symbiotic bands around $6830{\AA}$ and $7088{\AA}$, which have been identified by Schmid (1989) as the Raman scattered features of the O VI $1032{\AA}$ and $1038{\AA}$ doublet by atomic hydrogen. Due to the incoherency of the Raman scattering, these features have very broad profiles and they are also strongly polarized. In the accretion disk emission model, it is expected that the Raman features are polarized perpendicular to the binary axis and show multiple peak structures in the profile, because the neutral scatterers located near the giant component views the accretion disk in the edge-on direction. Assuming the presence of scattering regions outflowing in the polar directions, we may explain the additional red wing or red peak structure, which is polarized parallel to the binary axis. We argue that in the accretion disk emission model it is predicted that the profile of the Raman feature around $6830{\AA}$ is different from the profile of the $7088{\AA}$ because the O VI line optical depth varies locally around the white dwarf component. We conclude that the Raman scattered features are an important tool to investigate the physical conditions and geometrical configuration of the accretion disk in a symbiotic star.

• 가정과삶의질연구
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• 제26권5호
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• pp.1-14
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• 2008

The purpose of this study was to examine factors contributing to financial resources interchange type and amount of the middle aged and the elderly household. For this study, the 6th KLIPS data was used, and sample size was 1,679 households including those with head of household being over the age of 50. Statistical analysis was conducted to examine frequency, percentile, mean and standard deviation, Pearson's correlation, Anova, Duncan's multiple range test and Heckman analysis First, Interchange amount of Benefits type household was significantly different according to the householder's gender, existence or nonexistence of a spouse, age, educational background, home ownership, family type and place of residence. However, interchange amount of provide- type households were significantly different according tohouseholder's gender, existence or nonexistence of a spouse, educational background, whether retired or not, and home ownership. Second, The receptive type of households and net receptive expense of households in terms of the financial resources interchanges and the findings of Heckman analyses suggest that the variables to have a significant effect on the receptive types of financial interchanges were as gender, age, education level, retired or not, and current economics. Factors having an effects on net receptive expense were age, and family type and for the number of receptive of financial resources, whether there is the receptive of financial resources, total income, total asset. Third, The supplying type of households and net supplying expense of households in terms of the financial resources interchanges, whether or not the type of financially supplying households is significant were residential area, total income, house ownership. Factor having an effect net supplying expense were age, family type, whether there is the supplying of financial resources, family satisfaction, and house ownership.

• 대한가정학회지
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• 제39권6호
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• pp.25-40
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• 2001

The purpose of this study was to find out the amount of the household work time related to food and examine the factors affecting the time accomplished by married female home-based workers and on-site workers. The data were collected from 165 married female home-based workers, and 292 married female on-site workers in Pusan and Kyungnam province, by the self-administered questionnaire. frequency distributions, Cronbach's alpha, t-tests, Pearson's correlations, and multiple regression analyses were conducted by SPSS/PC+. The major findings of this study were as follows: (1) both married female home-based and on-site workers spent more time on household work related to food in a weekend than in a weekday, (2) in a weekday, occupation was significantly related to the amount of time that married female home-based workers spent on food household work, whereas age and occupation were significant for married female on-site workers, (3) on Saturday, the significant factors of the time spent on food household work were the number of family and occupation for married female home-based workers, and educational level, occupation, sex role attitude, existence of children of 6 years or under, and existence of elders/disability within the family for married female on-site workers, and (4) on Sunday, for married female home-based workers, the number of family, occupation, and the level of market good substitution had significant effects on the amount of time spent on food household work, and for married female on-site workers, age, the number of family, occupation, sex role attitude, work hours on Sunday, and the level of market good substitution were significant.