• Journal of Korean Philosophical Society
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• 제137권
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• pp.109-130
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• 2016

Plato learned of teleology from his teacher Socrates and expanded it to its application in cosmology. His cosmological work Timaeus was the final edition of teleological view. The motive that Demiurge created the cosmos was in resemblance of his goodness. He then modeled the idea of the Good imposing limit to the Forms of Good in a material world. In this sense, Demiurge was an excellent creator and created the Good cosmos. The cosmic body was made from four elements (water, fire, air, earth) and the cosmic soul entered the cosmic body and the cosmic intelligence (nous) entered the cosmic soul. According to these steps, this cosmos was created and named a living god. In conclusion, Plato asserts that this cosmos was created by God's teleological project, and resembles the goodness of a god. When man followed the order and balance in the cosmos, the good of the individual and the state would be accomplished.

• Journal of the Korea Construction Safety Engineering Association
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• 통권36호
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• pp.34-37
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• 2006

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제42권6호
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• pp.515-521
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• 2014

In this paper, we designed axis-displaced Gregorian antenna by using Ray-tracing method. This antenna improves gain, VSWR by rotating the axis of the sub-reflector to get rid of E-field wave returned from sub-reflector to feed horn. Therefore it reduce the sub-reflector size and the volume of antenna. This method is used to track the propagation path for radiation pattern of feed horn from feed horn to sub-reflector, main-reflector and air. We get E-field distribution of this antenna aperture and calculate antenna radiation pattern and optimize the antenna performance. The Ray-tracing Method was verified because the gain, radiation patterns, side lobe level, beam width and return loss of the designed antenna are very similar to CST simulation result and a measured result of the fabricated antenna.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제38권12호
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• pp.1223-1231
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• 2010

The design is presented for a SATCOM antenna capable of simultaneous multi-band (X/Ku/Ka-Band) communications without replacement of feed horns or change of other parts in the application as a ground satellite terminal for large data transfer. The antenna is the offset configuration and consists of a dual-band(X/Ka-band) feed horn, a single-band(Ku-band) feed horn, a frequency selective surface(FSS) sub-reflector and a parabolic main-reflector. The antenna has a main reflector defining a prime focus and a frequency selective surface sub-reflector defining an image focus. A dual-band feed and a single-band feed are provided at each of the prime focus and image focus. The antenna is designed using 3D EM simulator and the gains measured in X/Ku/Ka-band of the complete antenna assembly is more than 31.6dBi, 36.8dBi, 40.8dBi, and the cross polarization is 21.7dB, 26.6dB, 25.2dB, respectively.

• Aerospace Engineering and Technology
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• 제6권2호
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• pp.60-65
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• 2007

Acoustic chamber was developed for verifying the performance of a satellite under the launch condition on the Space environment test department. As the size of a satellite is increased the extension of existing facility is required. This paper encompasses the following items; redesign of components in acoustic chamber, product procedures of them and review of the test for the components of satellite in the upgraded acoustic chamber.

• Bulletin of the Korean Space Science Society
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.33.1-33.1
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• 2010

천상열차분야지도에는 유방택이 계산하여 작성한 중성기가 실려 있다. 중성기란 24절기일 각각에 대해 혼각과 효각에 자오선이위치하는 하늘의 입수도를 표로 만들어 놓은 것이다. 우리는 유방택이 사용할 수 있었던 역법이 선명력과 수시력이라고 생각하고, 우선 수시력에 의한 중성 계산법으로 을해중성기를 계산해 보았다. 이때 적도수도 값에 따라 중성기가 달라질 수 있는데, 유방택이 사용가능한 28수의 적도수도는 천상열차분야지도에 수록되어 있는 것, 수시력에서 사용한 것, 선명력에서 사용한 것이 있었을 것이다. 우리는 여기에 몇 가지 다른 적도수도들의 경우를 더하여 유방택이 어떤 계산 방법으로 중성기를 작성했는지 알아보았다. 그 결과, 베이징 기준의 수시력과 선명력의 적도수도의 조합이 을해중성기와 가장 가까운 결과를 주었으며, 천상열차분야지도의 적도수도와 수시력의 적도수도도 비교적 을해중성기에 가까운 결과를 주었다. 우리는 유방택이 선명력의 중성 계산 방법과 선명력의 적도수도를 사용하여 을해중성기를 작성한 것이 아닌가 추측하고 추후 연구를 계속하려고 한다.

• Journal of the Daesoon Academy of Sciences
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• 제45집
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• pp.1-35
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• 2023

This study aims at determining the meaning of Life in The Canonical Scripture of the Daesoon Thought upon the ontological bases of occidental philosophies; especially upon those of Plato and Bergson. In western philosophy, the word ontology designates investigating the meanings of being, which is derived from the Greek 'onto (being)' and 'logia (logical discourse).' The various meanings of life have been sought from ancient times all over the world, for these are the critical and vital questions that pertain to the nature of human existence. Plato had asserted that life, in his word, soul, had three different kinds of aspects of meaning. Immortal, reciprocal, and divine. Plato scheme was such that the soul could die, but after death it could became reborn into another various forms of living creatures. The real inner life of humans, the soul, would live eternally. Henri-Louis Bergson, a famous French philosopher from the 20^th century, claimed that life had three different kinds of aspects. Self-identity, Élan vital (vital impetus) and liberty. Bergson insisted especially the real meaning of life had been characterized by "unité multiple et multiplicitéune," "unity as something multiple and multiplicity something singular." The meaning of life in Daesoon Thought could be said to have three different characteristics, solidarity, earthly immortality and grievance-resolution. Some similarities can be found between certain western ontological meanings of life and those of Daesoon Thought. Namely, the qualities of eternity, reciprocity, and divinity.

• Journal of Astronomy and Space Sciences
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• 제14권1호
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• pp.67-79
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• 1997

We have designed the quasi optics of the dual channel receiver to observe the radio sources with 100GHz-band and 150GHz-band simultaneously. We introduced the general quasi optics and the relation between the Gaussian beam and thin lens approximation. We determined the parameters of the quasi optic components to match the beam waist at cassegrain focus with that of feed horn well.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제42권1호
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• pp.90-97
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• 2014

In this paper, we have designed the antenna for Korea SAT-5 Satellite Communication which can use Ka band in the earth station. The antenna structure consist of the the dual-offset gregorian reflector that has high gain and efficiency, the corrugated horn that has symmetric radiation patterns and low side lobe levels, the iris polarizer that make circular polarization and the OrthoMode Transducer that separate transmitting and receiving signals. The designed antenna gain is more than 45.7dBi in Tx-band which use LHCP and 42.0dBi in Rx-band which use RHCP. The co-polarized and cross-polarized radiation pattern comply with ITU-R S.580-6 and S.731-1 that are recommended by International Telecommunication Union in the geostationary satellite. The Axial ratio is less than 1.0dB in Tx-band and 1.5dB in Rx-band that meet MIL-STD-188-164A.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제24권12호
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• pp.1205-1214
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• 2013

Recently spaceborne SAR systems are increasing image resolution and frequency. As a high quality image resolution, the wider bandwidth is required and a wideband signal generator with RF component is very complicated and RF impairments of device is increased. Therefore, it is very important to improve performance by reducing these errors. In this study, the transmission signal of the wideband signal generator is applied to the phase noise, IQ imbalance, ripple gain, nonlinear model of high power amplifier. And we define possible structures of wideband signal generator and measure the PSLR and ISLR for the performance assesment. Also, we extract error of the amplitude and phase from the waveform and use a quadratic polynomial curve fitting and examine the performance change due to nonlinear device. Finally, we apply a high power amplifier predistortion method for non-linear error compensation. And we confirm that distortion in the output of the amplifier by intermodulation component is decreased by 15 dB.