• 한국해양환경ㆍ에너지학회지
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• 제10권4호
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• pp.187-192
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• 2007

플런징 쇄파에 의해 실린더에 작용하는 충격력을 실험적으로 고찰하였다. 쇄파는 조파기의 구동주파수를 선형적으로 감소시켜 수조의 목표지점에 파랑을 집중시킴으로써 생성되며, 쇄파의 파형은 등파기울기 스펙트럼을 채택하였다. 실린더와 쇄파 전면의 접촉각이 충격력에 미치는 영향을 고찰하기 위해 3개의 경사각을 적용하였으며, 압력 분포 및 정점 값에 대한 실린더 직경의 영향을 살피기 위해 3개의 서로 다른 직경을 갖는 실린더가 사용되었다. 충격 압력의 최대 값을 찾기 위해 실린더를 수조 길이방향으로 조금씩 이동하며 총 8개 지점에서 실험을 수행하였다. 실린더 표면의 압력과 합력은 piezo-electric형 압력계와 3축 로드셀을 사용하여 30 kHz의 빈도로 계측하였다. 실린더 직경, 경사각 및 회전각에 따른 정점 충격압력과 충격력의 변화를 분석하였으며, 실린더 표면의 압력분포를 고찰하였다. 실린더의 수조 내 위치 및 실린더 표면의 위치는 정점압력의 크기와 시계열 형상을 지배하는 주요 인자이며, 반면에 실린더 직경과 경사각의 영향은 상대적으로 미미하다. 충격현상은 매우 불안정하기 때문에 동일조건의 반복 실험에서도 계측 값의 넓은 분포가 발생한다.

• Journal of Preventive Medicine and Public Health
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• 제44권1호
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• pp.2-8
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• 2011

Objectives: Public release of and feedback (here after public release) on institutional (clinics and hospitals) cesarean section rates has had the effect of reducing cesarean section rates. However, compared to the isolated intervention, there was scant evidence of the effect of repeated public releases (RPR) on cesarean section rates. The objectives of this study were to evaluate the effect of RPR for reducing cesarean section rates. Methods: From January 2003 to July 2007, the nationwide monthly institutional cesarean section rates data (1 951 303 deliveries at 1194 institutions) were analyzed. We used autoregressive integrated moving average (ARIMA) time-series intervention models to assess the effect of the RPR on cesarean section rates and ordinal logistic regression model to determine the characteristics of the change in cesarean section rates. Results: Among four RPR, we found that only the first one (August 29, 2005) decreased the cesarean section rate (by 0.81 percent) and continued to have an impact period through the last observation in May 2007. Baseline cesarean section rates (OR, 4.7; 95% CI, 3.1 to 7.1) and annual number of deliveries (OR, 2.8; 95% CI, 1.6 to 4.7) of institutions in the upper third of each category at before first intervention had a significant contribution to the decrease of cesarean section rates. Conclusions: We could not found the evidence that RPR has had the significant effect of reducing cesarean section rates. Institutions with upper baseline cesarean section rates and annual number of deliveries were more responsive to RPR.

• 한국의류학회지
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• 제38권3호
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• pp.415-426
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• 2014

This study investigated the color change, enhancement of dye uptake, washing fastness, and light fastness of cotton and silk when dyed with Juniperus chinensis and Terminalia chebula (combination dyeing) using various methods. The dyeing methods were 1) dyeing Juniperus chinensis extract and Terminalia chebula Retzius extract sequentially (J-T), 2) dyeing Terminalia chebula Retzius extract and Juniperus chinensis extract sequentially (T-J), 3) dyeing Juniperus chinensis extract and Terminalia chebula Retzius extract simultaneously (J+T), and 4) dyeing Juniperus chinensis extract 4 times repeatedly and followed by a dyeing Terminalia chebula Retzius extract in sequence. In terms of increased dyeing uptake, combination dyeing (dyeing 2 times like method 1, 2, 3) had the same impact as the repeated dyeing (method 4). The color of J, T combination dyeing showed wide range of mixed YR series, Y series resulting from Terminalia chebula Retzius, and R series resulting from Juniperus chinensis. In cotton, J-T dyeing method showed superior enhancement of dye uptake, and T-J method in silk. In both of the cases, Y series color from Terminalia chebula Retzius extract was mainly shown (Y series color was superior to R series color after dyeing). Therefore, it is recommended for cotton to implement T-J method and for silk to implement J-T method in order to enhance both dyeing uptake and emphasize the color of R series. The K/S value of combination dyed fabrics was decreased by increasing washing time; however, the K/S value of combination dyed fabrics was increased by increasing UV irradiation time. But after repeated washing and longer UV irradiation, ${\Delta}E$ value of combination dyed fabric became smaller compared to fabric dyed with Juniperus chinensis only. Thus, it was found that after J, T combination dyeing, fabric became less prone to fading by washing and UV than after Juniperus chinensis single dyeing was done.

• Biomolecules & Therapeutics
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• 제21권4호
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• pp.313-322
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• 2013

Previous studies have demonstrated that repeated administration of the exogenous stress hormone corticosterone (CORT) induces dysregulation in the hypothalamic-pituitary-adrenal (HPA) axis and results in depression and anxiety. The current study sought to verify the impact of catechin (CTN) administration on chronic CORT-induced behavioral alterations using the forced swimming test (FST) and the elevated plus maze (EPM) test. Additionally, the effects of CTN on central noradrenergic systems were examined by observing changes in neuronal tyrosine hydroxylase (TH) immunoreactivity in rat brains. Male rats received 10, 20, or 40 mg/kg CTN (i.p.) 1 h prior to a daily injection of CORT for 21 consecutive days. The activation of the HPA axis in response to the repeated CORT injections was confirmed by measuring serum levels of CORT and the expression of corticotrophin-releasing factor (CRF) in the hypothalamus. Daily CTN administration significantly decreased immobility in the FST, increased open-arm exploration in the EPM test, and significantly blocked increases of TH expression in the locus coeruleus (LC). It also significantly enhanced the total number of line crossing in the open-field test (OFT), while individual differences in locomotor activities between experimental groups were not observed in the OFT. Taken together, these findings indicate that the administration of CTN prior to high-dose exogenous CORT significantly improves helpless behaviors, possibly by modulating the central noradrenergic system in rats. Therefore, CTN may be a useful agent for the treatment or alleviation of the complex symptoms associated with depression and anxiety disorders.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.1086-1097
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• 2021

This study examined the impact of using total mixed ration (TMR) and concentrate on feed intake, daily gain, carcass yield grade, and carcass quality grade of Hanwoo steers and its subsequent economic efficiency. Thirty six 7-month-old Hanwoo steers were assigned to one of the four treatment groups, and each group was divided into three repeated pens, with each repeated pen comprising three steers. The treatment groups were: 1) separate feeding with commercial concentrate and forage (namely, SCF) for the entire experimental period; 2) TMR feeding for a growing period followed by SCF for the early and late fattening period (namely, TMRGSCF); 3) TMR feeding for growing and an early fattening period followed by SCF for the late fattening period (namely, TMREFSCF); and 4) TMR feeding for the entire experimental period (namely, TMRW). The results showed that the SCF treatment had significantly (p < 0.05) higher feed intake during the growing period than other treatments. In contrast, the total feed intake had little difference during early and late fattening as well as the whole period regardless of feeding strategies. Daily gain showed no difference during the growing period. However, it was significantly higher in SCF and TMREFSCF treatments for the early and late fattening period, respectively (p < 0.05). The daily gain during the total raising period is in the order of TMREFSCF > TMRGSCF > SCF > TMRW. Carcass characteristics, including carcass weight, loin eye muscle area, and carcass yield grade, did not significantly differ among different treatments. However, TMRW treatment, wherein TMR was fed for a long time, showed that the cold carcass weight was less compared with other treatments, but carcass yield grade was higher with thinner backfat. Backfat thickness was in the order of SCF > TMRGSCF > TMREFSCF > TMRW, showing that the thickness reduced with longer TMR feeding (p < 0.05). TMRGSCF, which numerically had a higher carcass quality grade, showed higher economic efficiency, whereas SCF showed low economic efficiency. In conclusion, it was more feasible to apply TMR strategy in the growing and early fattening period and then SCF for the early or late fattening period to improve carcass yield, quality grade, and economic efficiency.

• 한국콘텐츠학회논문지
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• 제11권9호
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• pp.352-361
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• 2011

이 연구의 목적은 특수경비원들의 사건충격이 직무스트레스 및 대처능력에 미치는 영향을 규명하는데 있다. 이 연구는 2011년 4월 수도권(인천)소재 공항에서 재직하고 있는 특수경비원들을 모집단으로 설정한 후 판단표집법을 이용하여 최종분석에 이용된 사례 수는 총 239명이다. 연구에 사용된 설문지는 총 67문항으로 구성되었으며, SPSSWIN 18.0을 이용하여 빈도분석, 요인분석, 신뢰도분석, 회귀분석 등을 실시하였다. 설문지의 신뢰도는 Cronbach's ${\alpha}$값이 .779이상으로 나타났다. 결론은 다음과 같다. 첫째, 특수경비원들의 사건충격은 직무스트레스에 영향을 미친다. 즉, 침습이 자주 반복될수록 인간관계에 대한 스트레스는 증가한다. 또한, 과각성이 자주 반복될수록 역할에 대한 스트레스는 증가한다. 둘째, 특수경비원들의 사건충격은 대처능력에 영향을 미친다. 즉, 과각성이 자주 반복될수록 문제중심적 대처능력은 감소한다. 반면, 회피성향이 지속적으로 작용할수록 문제중심적 대처능력은 증가한다. 셋째, 특수경비원들의 직무스트레스는 대처능력에 영향을 미친다. 즉, 직무특성에 대한 무력감이 작용할수록 문제중심적 대처능력은 증가한다. 반면, 역할에 대한 모호성이 높게 작용할수록 문제중심적 대처능력, 사회적지지 추구능력은 감소한다.

• Management Science and Financial Engineering
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• 제16권2호
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• pp.81-97
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• 2010

Trust is one of the most important aspects of the relationship between retailers and consumers in e-commerce. Users may have concerns about transaction security or personal information leakage when they engage in transactions over the Internet. It can be difficult to attract customers if the retailers or service providers cannot establish trust with their customers. There have been many studies of trust-building mechanisms between customers and e-storefronts. However, little work has been done on identifying the relationships between customer satisfaction, purchase intention, and trust. In addition, trust building occurs in the pre- and post-purchase phases of an e-commerce transaction, as well as gradually over repeated transactions. Thus we distinguish between cue-based trust and experience-based trust. The objective of this study was to explain the impact of trust on customer satisfaction and purchase intention in relation to e-commerce sites from the perspective of a multi-dimensional concept of trust. We surveyed 350 undergraduate students and obtained 331 responses for analysis. The result of our analysis showed that cue-based trust has a positive relationship with trust based on experience. Although the two concepts of trust have positive relationships with satisfaction, the path coefficient of trust based on experience was higher than that of cue-based trust. In addition, the purchase intention mediates the relationship between cue-based trust and experience-based trust.

• Earthquakes and Structures
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• 제12권1호
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• pp.1-12
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• 2017

Historical earthquakes have shown that successive seismic events may occur in regions of high seismicity. Such a sequence of earthquakes has the potential to increase the damage level of the structures, since any rehabilitation between the successive ground motions is practically impossible due to lack of time. Few studies about this issue can be found in literature, most of which focused their attention on the seismic response of SDOF systems or planar frame structures. The aim of the present study is to examine the impact of seismic sequences on the damage level of 3D multistorey R/C buildings with various structural systems. For the purposes of the above investigation a comprehensive assessment is conducted using three double-symmetric and three asymmetric in plan medium-rise R/C buildings, which are designed on the basis of the current seismic codes. The buildings are analyzed by nonlinear time response analysis using 80 bidirectional seismic sequences. In order to account for the variable orientation of the seismic motion, the two horizontal accelerograms of each earthquake record are applied along horizontal orthogonal axes forming 12 different angles with the structural axes. The assessment of the results revealed that successive ground motions can lead to significant increase of the structural damage compared to the damage caused by the corresponding single seismic events. Furthermore, the incident angle can radically alter the successive earthquake phenomenon depending on the special characteristics of the structure, the number of the sequential earthquakes, as well as the distance of the record from the fault.

• 농촌계획
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• 제26권1호
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• pp.51-68
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• 2020

Korea's general rural development projects, which has shifted its paradigm to a bottom-up approach, should be promoted in the direction of focusing on the subjective well-being of the residents in rural areas. This study analyzed the effect that a general rural development project impact on the subjective well-being of the residents and the village leader in the relationship the spirituality of leadership, the village's social capital to analyze the impact any general rural areas, attributed the success of development projects with diversified.. The results are as follows: First, the basic living-based projects among general agricultural fishing village development projects have positive effects on the subjective welfare of the residents. Second, it was found that the basic living-based projects and regional income raising projects in general agricultural fishing village development projects had a positive effect on the altruistic behaviors and beliefs of spiritual leadership. Third, as a result of analyzing the effect of the level of general farming and fishing village development on social capital, regional income raising projects have a positive effect on the formation of social capital such as trust and network. Finally, as a result of analyzing the influence of social capital on subjective well-being, it was found that social capital such as trust and network has a positive effect on the subjective well-being of rural residents. In future research, it is required to select more extended research subjects not limited to residents of limited areas, and conduct repeated studies, with expanding the model to include the important variables that affect the subjective well-being of the residents.

• 자원리싸이클링
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• 제23권4호
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• pp.30-36
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• 2014

자동차 산업의 발달과 함께 환경오염 문제가 심각해지면서 연간 300,000톤 이상 발생하는 폐타이어의 재활용에 대한 관심이 높아지고 있다. 본 연구에서는 폐타이어 재활용을 목적으로 40, 80, 140 mesh 크기의 폐타이어 분말을 선별한 후, 입도 분석을 통하여 크기를 확인하고 그 형상을 SEM을 통해 관찰하였다. 또한 각각의 폐타이어 분말을 Virgin PP와 혼합하고 Intermeshing Corotating Twin Screw Extruder를 이용하여 TPV를 제조하고 특성 분석을 하였다. 이 중 효과가 좋은 140 mesh의 폐타이어 분말과 Virgin PP, Waste PP, PP-g-MA 세 가지 종류의 매트릭스를 다양한 비율로 혼합하여 TPV를 제조한 후 UTM을 통한 인장강도, 연신율과 Izod impact로 충격강도 등을 측정하였고 TGA로 열안정성을 확인하였다. 또한 SEM을 통하여 폐타이어 분말의 분산정도 및 파단면을 확인하였다.