• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.6
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• pp.64-74
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• 1999

The frequency of earthquake occurrence tends to increase in Korea. Therefore, the stability of pipeline, such as watersupply pipe, gas pipe, and oil pipe etc. across fault zones in Gyoung-sang landmass is very important, expecially , in metropolitan area. There were some examples of the construction of buried pipeline across fault zones in Korea. the interactiion between the buried pipeline across fault zones and the ground is considered. As well, in the interfaces of them, the direct shear numerical analysis model including elasto-plastic joint element is assumed that the retained dilatancy theory in them, otherwise. Also, the other elements are modeled the ground is nonlinear elastic coutinuaus beam, respectively. In this study, the maximum shear force point exist inside retaine zone(anchored zone) during shwar (as fault sliding), and the distribution of pipeline's behavior is all alike them of pipeline buried in ladnsliding grounds. Since the pipeline is not continuous beam but jointed by steel-pipe segments , practically, on acting of a large bending moment or a shear force, then, those are may be unstable. The reaearch on this point may be new approach.

• Journal of Korean Elementary Science Education
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• v.29 no.2
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• pp.195-206
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• 2010

The purposes of this study were to develop science education programs for changing students' science research ethical views, and to investigate the types and features of their views, and to examine their changes overtime. The subject of this study was one 6th grade class(41 students) at an elementary school located in Seoul. The scientific research ethical education programs developed in the study was applied through 8 lessons over 4 weeks. The results of this study show that 3 types of science research ethical views were appeared in elementary students participated in this study: 'human technology centered views', 'value ecology centered views' and the mixed views. The numbers of students, who changed their views from type I or type II to type III, were significantly increased. Students with type III appeared to actively involve in classroom activities aligned with science research ethical issues. The results imply that intended science ethical education program can affect students' ethical views on science. It is also important to aware that teacher's effective assistance and help contribute to students' meaningful changes on their traditional scientific ethical views. Educational implications on science education are discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1607-1611
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• 2001

The dependence of the performance of 40-Gb/s optical transmission using short pulses on the fiber chromatic dispersion is numerically studied. When very short pulses are used, the wide spectrum of the optical signal and the chromatic dispersion of the fiber interact in such a way that results in the reduction of nonlinear impairments of the transmission performance. The degree of this reduction is determined by the combined effects of chromatic dispersion of the fiber and the strength of the optical signal and the transmission distance. When 3ps-long pulses were used for the transmission, the eye-closure penalty was highest with the dispersion D=4ps/nm/km.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.1-7
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• 2020

In this study, a multichannel gas-liquid microextraction system is designed by integrating the automatic elution of extraction line and multichannel gas-purging liquid phase microextraction. The system uses an injection pump and inert gas to push the extraction solvent to a sample bottle of a gas-phase color autosampler and then implements multichannel gas-liquid microextraction and gas chromatography-mass spectrometry. The system also employs a three-way integrated micro-high-temperature heater, syringe pump, and microflow controller to realize the simultaneous processing of multiple groups of samples, thus improving the sample pretreatment speed and reproducibility and reducing human error. Autoinjection experiments were implemented with polycyclic aromatic hydrocarbon standard samples. The experiments show that the average recovery rate of the system exceeds 70%, and the relative standard among the channels is less than 15%.

• Journal of Environmental Impact Assessment
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• v.16 no.3
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• pp.207-227
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• 2007

본 연구는 오늘날 범지구적 차원에서 심각한 수준에 있는 생태계 파괴에 대한 사회학적 함의를 정립하는 데 목적이 있다. 이를 위해 먼저 생태계의 개념과 구조를 살펴보고, 다음으로 인간활동으로 인한 생태계 파괴의 메커니즘을 분석하고, 마지막으로 그 메커니즘에 기초하여 생태계 파괴에 대한 사회학적 함의를 정립하였다. 생태계로서의 자연은 인간 없이 존재할 수 있지만 인간은 자연 없이는 생존할 수 없다. 따라서 생계위기는 곧 인간의 위기다. 그럼에도 불구하고 18세기 산업혁명 이후 풍요성과 편리성 추구를 위한 인간의 활동 결과 지구는 점용환경용량을 2.5배 초과되었다. 이것은 인간이 범한 모순이다. 이 모순을 해결하면서 사회발전을 추진하자는 이념으로 1987년 지속가능발전이 제창되었고, 지속가능발전은 1990년대 중반에 지속가능사회로 대치되었고, 2000년대에 와서는 지속가능사회가 생태적 근대화로 대체되었다. 18세기 산업혁명 이후 풍요성과 편리성 증대를 위한 인간의 활동으로 생태계가 파괴되기 시작한 후, 생태계를 보전하면서 사회발전을 추진하자는 생태적 근대화 이념이 출현까지의 역사적 과정은 정(正)-반(反)-합(合)의 변증법 과정으로 이론화될 수 있다. 산업혁명 이전의 농업사회 때는 인간의 활동이 점용환경용량 범위 안에서 이루어졌기 때문에 환경문제가 없었다. 이 시대는 생태적 지속가능성이 유지되었기 때문에 생태적 합(合)의 상태라고 할 수 있다. 산업혁명 이후 인간의 활동이 생태계의 점용환경용량을 초월시킨 것은 생태계에 반(反)이 작용한 것이다. 따라서 범지구적 차원에서 환경문제의 심각성을 인식하고 지속가능발전을 위한 정책이 도입되기 이전까지 생태계는 정(正)과 반(反)이 대립상태에서 공존하였다. 1990년대 이후 생태적 지속가능성을 위한 각종 지속가능발전정책의 도입은 정(正)과 반(反)의 대립을 통해 다시 생태학적 합(合)의 상태를 지향하는 과정이라고 할 수 있다.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.164-169
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• 2010

Methyl (E,E,Z)-2,4,6-decatrienoate is the aggregation pheromone of brown-winged stink bug Plautia stali (Hemiptera: Pentatomidae). Attractiveness of the pheromone synthesized in Korea was compared with that of synthesized in Japan in the field. A lure filled with hexane was used as a control treatment. Catches in trap baited with Korean pheromone was significantly higher than that baited with Japanese one only in one orchard out of three sweet persimmon orchards in 2008. However there was no difference in trap catches between Korean and Japanese pheromones at three sites in 2009. Gas chromatography analysis showed that the components of both pheromones were not different each other. Monitoring of P. stali seasonal fluctuation using Korean pheromone showed that the bugs were most captured in August, 2008 and in September, 2009.

• Journal of Korean Elementary Science Education
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• v.26 no.1
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• pp.117-130
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• 2007

This study investigated the university proffssors', pre-service teachers' and in-service teachers' perceptions of the specialized science education courses in the 11 national universities of education in Korea, analyzed their perception differences, and made suggestions the future directions for the specialized courses. For this study, 46 university professors, 402 in-service teachers, and 336 pre-service teachers were participated nationwide. The results show that there were significant differences in their perceptions between the three groups. For university professors, for example, the acquisition of science content knowledge appeared to be the most important objective of the courses, whereas the other groups preferred the acquisition of more practical knowledge and skills that they could easily use and apply in their classroom teaching later. The university professors tended to think that the science specialized courses would be very useful to the teachers' teaching and contribute to developing their professionality. On the contrary, the in-service and pre-service teachers tended to think that the courses would be not so useful because science theories construct the courses rather than practical knowledge. The implications of these findings are discussed in relation to the future science teacher education.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.461-468
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• 2008

The needs for visualizing interactive multimedia contents on portable devices with realistic three dimensional shapes are increasing as new ubiquitous services are coming into reality. Especially in digital fashion applications with virtual reality technologies for clothes of various forms on different avatars, it is required to provide very high quality visual models over mobile networks. Due to limited network bandwidths and memory spaces of portable devices, it is very difficult to transmit visual data effectively and render realistic appearance of three dimensional images. In this thesis, we propose a compression method to reduce three dimensional data for digital fashion applications. The three dimensional model includes animation of avatar which require very large amounts of data over time. Our proposed method utilizes temporal and spatial coherence of animation data, to reduce the amount. By grouping vertices from three dimensional models, the entire animation is represented by a movement path of a few representative vertices. The existing three dimensional model compression approaches can get benefits from the proposed method by reducing the compression sources through grouping. We expect that the proposed method to be applied not only to three dimensional garment animations but also to generic deformable objects.

• Journal of The Korean Association For Science Education
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• v.18 no.3
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• pp.327-336
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• 1998

The purposes of this study were to investigate 6th-graders' use of cognitive strategies and metacognitive strategies in usual learning and testing situations, and to compare the difference in the use of the strategies by students' science achievement, learning motivation, and gender. The relationship among these strategies, science achievement, and learning motivation were also examined, and the portion of variance of explanation for achievement score was studied by a multiple regression analysis. The results showed that high-achieving students used more cognitive strategies and metacognitive strategies in usual learning and more cognitive strategies in testing situations than low-achieving students. Highly motivated students used more cognitive and metacognitive strategies than poorly motivated students in all situations. Elementary female students used more learning strategies than male students in usual learning. On the other hand, no gender differences was found to be significant in the use of strategies in testing situations. These learning strategies were significantly correlated with the science achievement and motivation scores. The cognitive strategies in usual learning accounted for the significant portion of the variance of the achievement score. Educational implications are discussed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.86-93
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• 2008

A low-power, low-noise, highly-linear hybrid balun circuit is proposed for 2.4-GHz fully differential CMOS direct conversion receivers. The hybrid balun is composed of a passive transformer and loss-compensating auxiliary amplifiers. Design issues regarding the optimal signal splitting and coupling between the transformer and compensating amplifiers are discussed. Implemented in $0.18{\mu}m$ CMOS process, the 2.4 GHz hybrid balun achieves 2.8 dB higher gain and 1.9 dB lower noise figure than its passive counterpart and +23 dBm of IIP3 only at a current consumption of 0.67 mA from 1.2 V supply. It is also examined that the hybrid balun can remarkably lower the total noise figure of a 2.4 GHz fully differential RF receiver only at a cost of 0.82 mW additional power dissipation.