• 아동학회지
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• 제20권2호
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• pp.171-186
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• 1999

This study investigated behavior problems of toddlers in the day care setting and difficulties of the caregivers due to such behaviors. The subjects were 24 toddlers enrolled in two day care centers and 56 caregivers at day care centers in Seoul. Toddlers were observed and teachers filled out questionnaires. Analysis of the data by $x^2$ and correlations revealed the kind of behavior problems frequently shown by toddlers, sex differences, differences between centers, and the caregivers' points of view regarding the frequency and difficulties of such behaviors.

• 한국건축시공학회지
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• 제12권6호
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• pp.607-614
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• 2012

In this study, the evolution of the electro-mechanical impedance (EMI) of a piezoelectric (PZT) patch embedded in fresh cement paste was investigated to discuss the possibility of monitoring the setting process of cement-based materials using an EMI sensing technique. A tailored thin square PZT patch was embedded in cement paste before casting, and EMI signatures of the embedded patch were continuously measured from casting up to 12 hours. A standard penetration resistance test was performed to compare and correlate the evolution of EMI during the setting process. The results showed that EMI responses differ according to the age of the cement paste, and that the behavior of the EMI resonance peak has a clear correlation with the penetration resistance of the cement paste. Based on the results, it is concluded that an EMI sensing technique using embedded PZT patch can be effectively applied to monitor the setting process of cement-based materials.

• 한국세라믹학회지
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• 제56권1호
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• pp.56-64
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• 2019

Calcium phosphate bone cement was prepared to contain antibiotics for release after setting using granulated ${\beta}$-tricalcium phosphate (${\beta}$-TCP) and hydroxyapatite (HA). Gentamicin sulfate (GS) solution was infiltrated within the interconnected pores of the granule to avoid affecting the setting reaction and for protection of GS during the setting. Consequently, the setting time and the temperature increase were not affected, regardless of the loading of GS. The release of the GS from the cement was estimated by measuring the concentration at regular intervals from the cement dipped solution. The ${\beta}$-TCP granule loaded with GS exhibited the saturation of accumulative concentration at 16 h. In contrast, the HA granule with GS exhibited steady increase in accumulative concentration of over $10{\mu}g/ml$ at 144 h. Thus, the granulated cement could release the GS greater than the minimum inhibitory concentration of staphylococcus during the prescription peroid of the oral antibiotics.

• 한국생활과학회지
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• 제15권6호
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• pp.919-935
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• 2006

The purpose of this study was to analyze the relationship between outdoor play environments and child's play behaviors. The data were collected by field measurement survey, and non-participatory observation from 9 child care centers in Daejeon. The field measurement survey were conducted from June 20 to July 20, 2004, whereas non-participatory behavior observation were conducted from September 2 to October 10, 2004. The major results showed the following. 1) The characteristics of outdoor play environment in child care centers showed that most of them were too small and did not use the adequate surfacing to play various activities. In many cases, outdoor play settings was made of play equipment setting, play props and manipulative settings, and tree/vegetation. 2) Child's play behavior has been focused on functional play activity and construction play activity. 3) The relationship between outdoor play environments and child's play behaviors showed that small outside play environment with monotonous construction and multi-complex play equipments produced functional play behaviors on children. On the other hand, where various play areas were put together, we could observe relatively diverse play behaviors. However, in some cases, despite the small and monotonous play area, diverse play behaviors were observed. These playgrounds at least differed from others in that they provided the place where multi purpose play was possible. This finding shows that multi purpose play areas can be an alternative in small playground environment.

• Journal of Biosystems Engineering
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• 제16권2호
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• pp.133-141
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• 1991

This study was undertaken to investigate the structural and configurational characteristics of the tailings return-unit in the commercially available head-feed combines and to study the aero-dynamical behavior of the tailings in the units. The mathematical model of the motion of tailings in the thrower casing was developed and the simulated trajectories for different type of units was analyzed to compare with the measured ones. The air-stream velocity profile in various locations along the tailings returning duct was measured to find the effect of configurational characteristics and blade tip speed. The results of the study are summerized as follows. 1. The ejecting angle, which is the angle between the direction of the particle velocity ejecting from the blade and the horizontal axis, was found to be about $66^{\circ}$ in both the simulation and experiment. The angle was much greater than the setting angle of actual duct of the combines studied, which were $48{\sim}56^{\circ}$. By comparison of these results, it was suggested to change duct setting angle so as to reduce the frictional force, between the duct wall and tailings, by reducing the difference between the ejecting and setting angles. 2. The velocity of the air stream in the duct was in general higher in the upper bound of the duct compared to the lower and decreased as the stream went toward the end of duct. The comparison of the tailings units among the combines studied showed a superior performance with the tapered duct having small diameter in the outlet and with greater number of thrower blade.

• 콘크리트학회논문집
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• 제16권1호
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• pp.54-60
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• 2004

발포폴리스티렌(EPS)의 효율적인 재활용 기술개발의 일환으로서 폐 발포폴리스티렌을 중합성 모노머인 스티렌에 용해한 고분자 용액에 가교제, 개시제, 촉진제 등을 첨가하여 상온 중합성 결합재를 개발하였으며 이를 이용한 폴리스티렌 모르타르를 제조하여 그 중요한 경화특성인 사용가능시간, 건조양생재령에 따른 발열온도 및 길이변화 거동에 미치는 폐 발포폴리스티렌 용액농도 및 TMPTMA 첨가량의 영향에 대해서 검토하였다. EPS용액을 이용한 결합재 및 폴리스티렌 모르타르의 사용가능시간은 EPS용액 농도 및 TMPTMA 첨가율의 증가에 따라서 짧아지며, 또한 폴리스티렌 모르타르의 경화에 따른 길이변화는 EPS용액 농도 및 TMPTMA 첨가율에 크게 영향을 받는데 이를 적절히 조절하여 경화특성을 제어함으로써 저수축 혹은 무수축 폴리스티렌 모르타르의 제조가 가능하다는 것을 검증하고 있다.

• 한국학교보건학회지
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• 제26권2호
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• pp.114-123
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• 2013

Purpose: The purpose of this study was to compare life skill's levels of adolescents. Methods: This was descriptive comparative survey using as convenience sample of 460, fifth and sixth grades in elementary school in Seoul Korea. The life skill was measured by life skill scale that 78 items regarding self esteem, social skill, decision making skill, and goal setting skill. Collected data were analyzed by frequency, mean, t-test and Pearson correlation using the SPSS/WIN 20.0. Results: The family-related self-esteem was higher ($26.02{\pm}3.73$) than other self-esteem score. Low family-related self-esteem associated with health behavior such as current drinking, accessing to pornography sites on internet in adolescents. There was a significant positive correlation between self-esteems (cognitive, peer, family, body, general), decision making skill and goal-setting skill. Conclusion: The results of this study suggest that it is important to develop a program that focuses on enhancing family-related self-esteem to effectively reduce the risk behaviors among adolescents.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.469-474
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• 1999

The object of study is analysis to joint crack behavior of cracked joint concrete pavement. In the new constructing concrete pavement, joint crack behavior was compared general joint depth D/4 with joint depth D/3 and D/5 that it's environmental effects changed temperature and humidity. After joint saw cutting joint section was predicted crack at joint depth D/5 test section from the result for monitoring development of crack. In the setting of data logger system of the joint section, it's data compared see with the naked eye. In the research, development of crack at the joint section should effect to joint saw timing latter than joint depth. This performance could be the minimum of deterioration to the early curing. In this research, At new constructing of joint concrete pavement of highway, the monitoring system be setting after finished paving and joint sawing. The system and see with the naked eye could be analysis to pavement behaviors from collecting data at the test section. This system could be monitoring shot term and long term. In this report, joint section of crack behavior analysis used to collected data during a month after paving and joint sawing.

• 제어로봇시스템학회논문지
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• 제19권11호
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• pp.1017-1021
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• 2013

The traffic signal has been widely used in the transport system with a fixed time interval currently. This kind of setting time was determined based on experience for vehicles to generate a waiting time while allowing pedestrians crossing the street. However, this strict setting causes inefficient problems in terms of economic and safety crossing. In this research, we propose a monitoring algorithm to detect, track and check pedestrian crossing the crosswalk by the patterns of behavior. This monitoring system ensures the safety for pedestrian and keeps the traffic flow in efficient. In this algorithm, pedestrians are detected by using HOG feature which is robust to illumination changes in outdoor environment. According to a complex computation, the parallel process with the GPU as well as CPU is adopted for real-time processing. Therefore, pedestrians are tracked by the relationship of hue channel in image sequence according to the predefined pedestrian zone. Finally, the system checks the pedestrians' crossing on the crosswalk by its HOG based behavior patterns. In experiments, the parallel processing by both GPU and CPU was performed so that the result reaches 16 FPS (Frame Per Second). The accuracy of detection and tracking was 93.7% and 91.2%, respectively.

• 한국지구과학회지
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• 제25권3호
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• pp.142-151
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• 2004

This study was designed to determine whether visitor behavior at science museums differs across various exhibit styles and between Family and Non Family groups. Eight exhibits in the natural history sections of the national science museum located in Daejeon were identified to have distinctive characteristics and styles. At each selected exhibit, visitor behavior was observed for an hour. An average of eighty people stopped by each exhibit. Descriptive analyses of visitors behaviors showed that: 1) families spent more time than non-family visitors; 2) families paid more attention to exhibits, for instance, they talked and commented about the exhibits; 3) exhibit characteristics related to holding power and attention span; 4) families more frequently visited exhibits related to school curriculum rather than ones that looked attractive, fun or novel. Visitors did not play with sensory simulation types of exhibits as much as expected. This implicates that exhibit style does not guarantee long visitors holding time and attracting power. Non-significant results are explained in terms of environmental and exhibit-related factors. Several potential factors including visitor factors, setting factors, and exhibit factors are discussed and explored with topics proposed for future study.