• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.304-311
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• 2022

Although the SEAD(suppression to enemy air defenses) mission is a strategically important task in modern warfare, the high risk of direct exposure to enemy air defense assets forces to use of unmanned aerial vehicles. this paper proposes a path planning algorithm for SEAD mission for an unmanned aerial vehicle and a method for calculating the mission effectiveness on the planned path. Based on the RRT-based path planning algorithm, a low-altitude ingress/egress flight path that can consider the enemy's short-range air defense threat was generated. The Dubins path-based Intercept path planning technique was used to generate a path that is the shortest path while avoiding the enemy's short-range anti-aircraft threat as much as possible. The ingress/intercept/egress paths were connected in order. In addition, mission effectiveness consisting of fuel consumption, the survival probability, the time required to perform the mission, and the target destruction probability was calculated based on the generated path. The proposed techniques were verified through a scenario.

• Korean Journal of Childcare and Education
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• v.6 no.2
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• pp.1-15
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• 2010

The purpose of this study is to investigate the difference between using computers for an Information Literacy Abilities of Young Children(ILAYC) and development of the ILAYC, with regard to following factors: computer use at home, learning in educational facilities for early childhood, and parents' recognition toward computer-assisted education. The data were obtained from random sampling of 4-year old children in educational facilities for early childhood located in J city. The research was conducted in order to measure ILAYC, using the questionnaire for teachers from September 3 to 27, 2009. The t-test to investigate computer utilization ability and information literacy ability for young children revealed that the ILAYC was not significantly influenced by their computer use at home, while the ILAYC varied with learning in educational facilities and parents' recognition toward computer-assisted education. These are resulted from parents' different recognition toward computer-assisted education when they select an educational facility for early childhood.

• International Journal of Knowledge Content Development & Technology
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• v.5 no.1
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• pp.15-32
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• 2015

This article analyzes motivations behind social sciences blog posts citing journal articles in order to find out whether blog citations are good indicators for the societal impact or benefits of research. A random sample of 300 social sciences blog posts (out of 1,233 blog posts) from ResearchBlogging.org published between 01/01/2012 to 18/06/2014 were subjected to content analysis. The 300 blog posts had 472 references including 424 journal articles from 269 different journals. Sixty-one (22.68%) of all cited journals were from the social sciences and most of the journals with high frequency were highly cited general science journals such as PNAS and Science. Seventy-five percent of all journals were referenced only once. The average age of articles cited at the time of citation was 5.8 years. Discussion and criticism were the two main categories of motivations. Overall, the study shows the potential of blog citations as an altmetric measure and as a proxy for assessing the research impact. A considerable number of citation motivations in blogs such as disputing a belief, suggesting policies, providing a solution to a problem, reacting to media, criticism and the like seemed to support gaining societal benefits. Societal benefits are considered as helping stimulate new approaches to social issues, or informing public debate and policymaking. Lower self-citation (compared to some other altmetric measures such as tweets) and the fact that blogging involves generating content (i.e. an intellectual process) give them an advantage for altmetrics. However, limitations and contextual issues such as disciplinary differences and low uptake of altmetrics, in general, in scholarly communication should not be ignored when using blogs as a data source for altmetrics.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.101-111
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• 2005

Various urban transport policies have an effect on urban transit riderships and accessibility. This study reports variations of metropolitan subway travel patterns affected by an enormous change in bus routes and transfer discount fare policy between subway and bus mode conducted by Seoul city in July 1st of 2004. In an effort to see the difference between the before and the after policies, two data sets are prepared. Firstly, on a daily bassis. an origin-destination trip table of May of 2004 is used. Secondly, on a daily bassis, an origin-destination trip table of August-September of 2004 is used as a counter measure. Even if seasonal variation was not considered, Seoul metropolitan area have experienced increasing riderships and accessibility. Finally, the effects of accessibility in spatial interaction model by rall service changes such as random shocks were scrutinized and interpreted in detail.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.21 no.2
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• pp.39-46
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• 2015

Background: The purpose of this study was to investigate the influence of short-term treadmill walking with high-heeled shoes on electromyography activities of the medial gastrocnemius, lateral gastrocnemius and tibialis anterior in healthy young females. Methods: Fifteen healthy females were recruited for this study. To measure muscle activation, the subjects were asked in random order to walk on a treadmill using either high-heeled shoes or barefoot conditions. The shoe heel height for high-heeled walking was 7 cm. The walking speed on the treadmill was 4 km/h, and the inclination rate of the treadmill was 10%. The subjects performed treadmill walking in the barefoot and high-heeled walking conditions for 5 minutes. Electromyography data were collected from the tibialis anterior, medial gastrocnemius, lateral gastrocnemius, and soleus on both firm and foam surfaces and during eyes-open and-closed conditions while standing. Results: Tibialis anterior activity was significantly different before and after the walking task while standing on a foam surface with eyes closed (p<.05). Conclusion: This finding suggests that the activity of the tibialis anterior may be lowered after high-heeled walking. Therefore, high-heeled shoes contribute to harmful effects at the ankle joints, increasing the risks of falling and musculoskeletal injury.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.453-460
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• 2017

High voltage power transmission lines have been to keep the proper dip for maintenance. Powerline dips at a random point are conventionally measured by the direct or indirect observation but it is not only unsafe but labor-intensive. Therefore in this study we applied the photogrammetric technique to remotely measure the powerline dips. Since it is not easy to extract conjugate points from linear powerlines, we exploited the epipolar lines acrossing the powerlines for 3D mapping of the powerlines and dip measurements. The vertical mapping accuracy estimated at two field-surveyed power line points was 15~16cm that are within 5% of deflection at the points and less than 3% of the powerline dip.

• Journal of the Korean Society of School Health
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• v.21 no.2
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• pp.35-46
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• 2008

Purpose: This study was a part of preliminary survey for establishing Korean HPS(Health Promoting School) model which was originally suggested by WHO. Methods: Three elementary and middle schools were sampled in urban and rural area across three level of social-economic status, and survey was conducted on one class in each grade by random selection. To measure mental health and social and familial factors, self-esteem scale, self-efficacy scale, depression scale, family cohesion scale, parent-child communication scale, adolescent's mental health and problem behavior questionnaire(AMPQ), and other question items about family status and economic level were conducted. Students' mental health level was compared by region, sex, grade, and other familial and economic factors. Results: Familial and social factors such as economical and educational level of parents, number of family members were different between rural and urban area. Also, students of rural area got lower scores at self-esteem, self-efficacy, but higher scores at extroverted problem behavior than their urban counterparts. In pre-school students, high grade students' self-esteem, and family cohesion scores were lower than low grade students. And sexual differences were found across problem behavior domain and region in middle school students. Especially, the students of single-parent family and lower economic family got insistently low scores at various mental health related scales. Conclusion: These results should be considered, when the HPS model is designed and applied in Korea.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.628-632
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• 2005

Remote sensing through atmospheric turbulence had been hard works for a long time, because wavefront distortion due to the Earth's atmospheric turbulence deteriorates image quality. But due to the appearance of adaptive optics, it is no longer difficult things. Adaptive optics is the technology to correct random optical wavefront distortions in real time. For past three decades, research on adaptive optics has been performed actively. Currently, most of newly built telescopes have adaptive optical systems. Adaptive optical system is typically composed of three parts, wavefront sensing, wavefront correction and control. In this work, the wavefront sensing technology for adaptive optical system is treated. More specifically, shearing interferometers and Shack-Hartmann wavefront sensors are considered. Both of them are zonal wavefront sensors and measure the slope of a wavefront. . In this study, the shearing interferometer is made up of four right-angle prisms, whose relative sliding motions provide the lateral shearing and phase shifts necessary for wavefront measurement. Further, a special phase-measuring least-squares algorithm is adopted to compensate for the phase-shifting error caused by the variation in the thickness of the index-matching oil between the prisms. Shack-Hartmann wavefront sensors are widely used in adaptive optics for wavefront sensing. It uses an array of identical positive lenslets. And each lenslet acts as a subaperture and produces spot image. Distortion of an input wavefront changes the location of spot image. And the slope of a wavefront is obtained by measuring this relative deviation of spot image. Structures and measuring algorithms of each sensor will be presented. Also, the results of wavefront measurement will be given. Using these wavefront sensing technology, an adaptive optical system will be built in the future.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.142-145
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• 2005

Since the successful launch of FORMOSAT -2 satellite by National Space Organization of Taiwan in May 2004, the Remote Sensing Instrument (RSI) on- board the FORMOSAT -2 has continuously acquired images at one panchromatic and four multi-spectral bands (http://www.nspo.org.tw). In general, the RSI performs well and receives high quality images which proved to be very useful for various applications. However, some RSI panchromatic products exhibit obvious trembling artifact that must be removed. Preliminary study reveals that the trembling artifact is caused by the instability of the spacecraft attitude. Though the magnitude of this artifact is actually less than half of a pixel, it affects the applicability of panchromatic products. A procedure removing this artifact is therefore needed for providing image products of consistent quality. Due to the nature of trembling artifact, it is impossible to describe the trembling amount by employing an analytic model. Relied only on image itself, an algorithm determining trembling amount and removing accordingly the trembling artifact is proposed. The algorithm consists of 3 stages. First, a cross-correlation based scheme is used to measure the relative shift between adjacent scan lines. Follows, the trembling amount is estimated from the measured value. For this purpose, the Fourier transform is utilized to characterize random shifts in frequency domain. An adaptive estimation method is then applied to deduce the approximate trembling amount. In the subsequent stage, image re-sampling operation is applied to restore the trembling-free product. Experimental results show that by applying the proposed algorithm, the unpleasant trembling artifact is no longer evident.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.790-799
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• 2010

The Upper Devonian Grossmont Formation in Alberta, Canada reserves an estimated 50 billion cubic meters of bitumen and possess about 1/6 of the total bitumen resources in northern Alberta. However, unlike the overlying Athabasca oil sands, non conventional bitumen resources has not been developed as yet. The carbonate rocks of Grosmont Formation have been subject to various stages of diagenesis, including dolomatization and karstification with a strong effect on the distribution of porosity and permeability, which resulted in highly heterogeneous reservoirs. An extensive fracture logging and mapping was performed on total of six boreholes located in the study area to explore the characteristics of fracture geometry system and the subsurface structures of carbonates reservoir that holds bitumen. Fractal dimension was used as a measure of the statistical homogeneity of the fractured rock masses. The applicability of random Cantor dust, Dc, as a fractal parameter was examined systematically. The statistical homogeneity of fractured carbonates rock masses was investigated in the study area. The structural domains of the rock masses were delineated depthwise according to estimated Dc. The major fracture orientation was dominated by horizontal beddings having dip of $0-20^{\circ}$. Also, fractures having high dip angles existed with relatively low frequency. Three dimensional fracture network modeling for each structural domain has been performed based on fracture orientation and intensity, and some representative conceptual models for carbonates reservoir in the study area has been proposed. The developed subsurface conceptual models will be used to capture the geomechanical characteristics of the carbonates reservoir.