• Bulletin of the Korean Space Science Society
• /
• 2009.10a
• /
• pp.32.5-33
• /
• 2009

카네기 천문대에서 주도하여 개발 중인 구경 25.4m GMT 망원경 사업에 한국도 공식적으로 참여하였다. 현재 한국천문연구원은 GMT(Giant Magellan Telescope)부경부를 국내에서 개발하고자 이와 관련된 연구를 진행하고 있다. GMT 부경은 직경 1.06m 오목거울 7장이 모여 전체 직경 3.2m인 타원면을 형성하고 초점비는 F/0.7이다. GMT 부경개발 선행 연구과제로 카네기 천문대에서 개발되어 현재 운용중인 구경 6.5m 마젤란 망원경의 부경을 선택하였는데, 이는 마젤란 부경의 형상과 직경, 부경시스템 운영방식이 GMT 와 유사하기 때문이다. 천체관측 망원경에서 거울면의 변형에 가장 큰 영향을 미치는 인자는 거울의 자중이다. 거울의 직경이 커지면 자중이 증가하게 되어 거울면의 처짐이 커지게 된다. 이를 극복하고자 다양한 거울 support들이 개발되었다. 그중에서 counterweight lever 시스템 같은 부양(float) 시스템은 자중의 영향을 보상해 줌으로써 그것에 의한 거울의 변형을 최소화하는 역할을 하는데, GMT 부경 개발에 근간이 되는 마젤란 부경 또한 부양 시스템을 도입하였다. 마젤란 부경의 부양시스템은 counterweight lever 시스템과 유사한 진공 시스템을 도입하였다. 마젤란 부경의 support는 axial 방향으로 거울을 지지하는 axial support와 lateral 방향으로 거울을 지지하는 lateral support가 있는데, 이중에서 axial support가 진공시스템으로 구성된다. Lateral 방향의 지지는 경량화된 거울의 hole 안에 3개의 판스프링을 삽입하여 단지 거울과 판스링의 강성에 의해서만 이루어진다. 이 논문에서는 망원경이 작동을 할때 즉, 천정각(zenith angle)이 변할 때 axial support와 lateral support의 조합(combination)에 의해 지지되는 마젤란 부경의 표면 정밀도 RMS 값을 비교하였다.

• Journal of Korean Society of Disaster and Security
• /
• v.15 no.4
• /
• pp.31-38
• /
• 2022

In the case of special bridges whose superstructure is supported by cables, there are many blind spots that are difficult to access without special equipment and personnel. As a result, there are difficulties in the safety inspection of special bridges. The purpose of this study is to review the inspection blind spots of cable-supported bridges such as cable-stayed bridges and suspension bridges, and to study ways to eliminate blind spots using drones. To this end, the cables, stiffened girder, and pylons of the cable-stayed bridge located in the sea were inspected using drones. Through this study, it was confirmed that external safety inspection of special bridges that are difficult for inspectors to access is possible using drones. In particular, drone inspection to check the external condition and damage of the pylon, which is a blind spot for inspection of special bridges, is a very effective safety inspection method.

• Geotechnical Engineering
• /
• v.12 no.3
• /
• pp.127-148
• /
• 1996

Recently, foundations of heavy structures such as bridge abutments have been built on slopes or near the crest of slopes at an increasing rate. Because the bearing capacity of such foundations is considerably lower than the bearing capacity of the same soil on a level ground, deep footings such as piles and caissons are often used. However, the costs of such methods are generally very high. One of the new techniques to overcome the problem is to place reinforcing members such as geosynthetics or metal strips horizontally at some depths beneath the footings. Rational methods of analysis to predict the bearing capacity of footings in reinforced slopes are therefore needed. This paper proposes an analytical method for estimating the increase in bearing capacity gained from the included horizontal strips or ties of tensile reinforcing in the foundation soil below the footing built near the crest of a slope. A failure mechanism, including the concept of'wide slab effect', adopted in the present study for analyzing the bearing capacity of foundations in reinforced slopes, is established through the observed model test behaviors described by Binquet SE Lee and Huang et al, and the Boussinesq solutions. The analytical results are then compared with the experimental data described in the paper by Huang et al. Also in order to properly evaluate the soil reinforcement interaction, typical pullout test values of the apparent friction coefficient, which usually vary with depths owing to both the increase of the shearing volume and the increase in local stress caused by soil dilatancy, are analyzed and related functionally. Furthermore, analytical parametric studies are carried out to investigate the effect and significance of various pertinent parameters associated with design of reinforced slope foundations. Keywords : Bearing capacity, Reinforced slope, Slab effect, Friction coefficient.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.4
• /
• pp.175-184
• /
• 1999

Several major land reclamation projects such as the Inchon International Airport construction, Songdo New City construction, LNG Tank and LPG storage construction are underway along the coastal line of Inchon in Korea. This study was carried out to investigate the feasible use of waste lime in the land reclamation projects. Waste lime (hydrated lime) used in this study is produced as a by-product in the manufacturing process of $Na_2CO_3$ from local chemical factory in Inchon. This study presents the characteristics of bearing capacity and settlement on the ground formed by layers of waste lime and dredged soil. From the laboratory and in-situ plate load test, the ultimate bearing capacity by in-situ test was 1.25~1.37 times higher than that of the theoretical ultimate bearing capacity. Based on the settlement analysis by Magset- II, the total settlement of layered ground steadly increased up to the ratio of waste lime depth 0.2 and therefore rapidly increased with the increase of waste lime depth. The results of the present study indicate that the ratio of waste lime depth for reclamation work is about 0.2.

• Journal of Family Resource Management and Policy Review
• /
• v.19 no.2
• /
• pp.1-26
• /
• 2015

The purpose of this study was to analyze the quality of life (QoL) of elderly women and the effect of social support on their QoL. The data were used 'urvey on the Elderly in 2011', which was held from 'Ministry of Health & Welfare' and 'Korea Institute for Health and Social Affairs'. Among the total 15,146 respondents, 3,880 of elderly women whose age was over 65, and who did not live together with their married children were included in the analysis. Multiple regression analysis and path analysis were used to analyze the research model. The findings were as follows. First, from the fact that the elderly women showed the highest mean in 'contact frequency with friends' among social support, it seemed that the elderly women contacted their friends more than their children in their old age. Among the support types from their children, elderly women received emotional support, physical support, instrumental support in order and irregular cash as a way of economic support. Second, from the regression results, the most critical factor that affected the QoL of elderly women was 'subjective physical condition level' and 'subjective standard of living' comes next. Third, the most important factor was 'subjective standard of living' from path analysis results, and 'subjective physical condition level' and 'total amount of annual income' in order. Also, social supports such as 'phone call contact frequency with children', 'emotional support from children', phone call contact frequency with relatives', 'phone call contact frequency with friends' positively affected the QoL of elderly women. Therefore, raising social supports from children, relatives, and friends positively contributes to improve the QoL of elderly women directly and indirectly. The results show that social supporters, which is a part of the structural aspects of social support, and types of social support, which lies in functional aspects, directly affect QoL of the elderly women and turn out to be factors that improve the QoL as mediating variables. It is concluded that the social supports can be the most important resources that make up declining personal and social resources in old age and maintain the QoL of elderly women.

• Journal of the Korean Geotechnical Society
• /
• v.35 no.12
• /
• pp.69-89
• /
• 2019

Design chart solution and table solution were proposed by Choi et al. (2019a), which conducted a parametric numerical study for the bored PHC piles socketed into weathered rocks through sandy soil layers. Based on the Choi et al. (2019a), the new prediction formulae for mobilized capacity components such as total capacity, total skin friction and skin friction of sand at the settlement of 5% pile diameter were proposed in this study. The proposed prediction formulae (EQ-G1) considers pile diameter, relative embedment length and ${\bar{N}}$ (i.e, corrected N) value and their verification results are as follows. The SRF calculated from the new proposed design method was 71~94%, which are greatly improved compared with results by the existing design method. The design efficiency of bearing capacity was in the range of reasonable design except 4 cases, and the design efficiency of the PHC pile was evaluated as 85%. Therefore, it is possible that allowable compressive load (P_all) of PHC pile can be utilized in the resonable design by means of the new proposed method using EQ-G1 equations. And the other new proposed equations of EQ-G2-3 can be utilized approximately in calculation of axial compressive bearing capacity components for prebored PHC pile.

• Journal of the Korea Convergence Society
• /
• v.8 no.1
• /
• pp.131-138
• /
• 2017

The purpose of research and bamboo for failure, Damyang-county, Jeollanam-do at 2015 Damyang bamboo the world fairs held according to the attachment to local factors impact of regional development and hosting support. To identify the impact on the property held. Fair after setting up a hypothesis to carry out research in the visitors through after sample surveys and survey and Empirical Analysis. Show areas are improving in the future, due to host tourists want to come up with the purpose of research to become a popular tourist attraction again. Attachment or environmental factors and social factors showed that, and affect the region. The host of social factors turned out to be the biggest influence, and economic factors, environmental factors shown to affect, and to a venue in order.Attachment is a factor appears to be affecting the region was the venue. The property is shown to environmental factors is not statistically significant, and host local affection, support appears to be factors affecting the holding. As a result, Fair, held regional attachment to the Influence Factors of regional development support, and according to the next fair in the Region and through the impact on the property held.Evaluation strategy could contribute to explore the festival.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.3
• /
• pp.145-156
• /
• 2015

The aim of this study is to identify whether the domestic violence experience of children has an impact on their game addition and to verify the direct effects and moderating effects of social support. The survey was conducted to the children who were 5th and 6th graders in Gwangju and Jeonnam. The responses from 328 subjects of domestic violence experience from were analyzed. The analytic results are as the following. When verifying the impact of a domestic violence experience of children on their game addiction, domestict violence was found as the key variable that has a negative impact on children's game addiction. The results indicated that children with higher levels of domestict violence more likely to have higher levels of game addiction. Furthermore, boy's addiction degree to game was higher than girls' and lower education levels of mother, higher grades were found to be associated with higher game addiction. The impact of children's social support on their game addiction was analyzed. The analytic results suggest that social support has a impact on their game addiction. In other words, higher social support means lower game addiction. The moderating effect of social support was analyzed. Social support check the moderating effect of domestic violence of children on their game addiction. The Implications of these findings were discussed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.12
• /
• pp.8525-8534
• /
• 2015

The purpose of this study was to investigate relations among the Health Promotion Behavior, Physically, Psychological, and Social factors of the stroke patients. The subjects include the patients that were Stroke was diagnosed and being admitted to hospital. The data of total 223 stroke patients were used in analysis. Collected data were analyzed with descriptive statistics, t-test, ANOVA, Pearson correlation, and Structural Equation Analysis. As a result, The higher medical support health promotion behavior scores were higher. Health Promotion Behavior had correlations with the subjective health state(r=.56, p=.000), family support (r=.68, p=.000), medical support(r=.65, p=.000), Fatigue(r=.27, p=.004), and behavioral intentions(r=.75, p=.000). Factors Affecting Health Promotion Behaviors of the Stroke patients Physically factors of(${\beta}$=-.156, p=.014), Psychological factors of subjective health(${\beta}$ =.283, p=.001), behavioral intentions((${\beta}$=.362, p=.000), Social factors such as family support(${\beta}$=.219, p=.010), the medical support(${\beta}$=.246, p=.004) was found to be significant influence factors. In conclusion, health promotion behavior in stroke patients is subjective health, behavioral intentions, a family support. The higher medical support health promoting behavior appears score was found to be highly Psychological factors and social factors are important factors in promoting healthy behavior. Therefore, psychosocial personalized approach to maintaining the stroke health promotion, health promotion action program itdaneunde be used as basis for relapse prevention is significant.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.3
• /
• pp.253-260
• /
• 2016

This paper proposes a planar Log-Periodic Dipole Array(LPDA) antenna with light-weight supporting structure for installing on an aircraft. The proposed antenna is designed by applying a planar skeleton supporting structure that has light-weight for an aircraft and is capable of withstanding structural vibration. The material of the planar skeleton supporting structure is a Polyether ether ketone(Peek) which has excellent characteristics on strength and temperature. The proposed antenna is fabricated by attaching the radiating elements of the LPDA on both sides of the supporting structure. The changed input impedance due to the dielectric material of the supporting structure was compensated for by controlling the distance and length of several radiating elements. The 10-dB return loss bandwidths of the designed planar LPDA antenna with light-weight supporting structure are obtained as 0.4~3.1 GHz(7.3:1) in the simulation and 0.41~3.5 GHz(8.2:1) in the measurement. The average gains in 0.5~3 GHz band are 6.77 dBi in the simulation and 6.55 dBi in the measurement. Therefore, we confirm that the designed antenna is appropriate to be installed on an aircraft due to its light-weight structure and wideband directional radiation characteristics.