• Publications of The Korean Astronomical Society
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• v.31 no.3
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• pp.65-76
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• 2016

We study a manuscript that includes 28 oriental constellations in the flags of barracks in Gangjin. According to the Joseon Chronicles, the constellation flags in the manuscript are thought to have originated from Seon-Pil Kim (金善弼) who first made 28 constellation flags for the barracks in 1878 during the Joseon Dynasty. Seon-Pil Kim was a commander and he used the 28 constellation flags for communications in a military camp. The flags also contain 28 animals and letter-like symbols with constellation maps. We examine the constellation maps in flags in terms of shapes and number of stars, and compare them with those of constellations in the Korean and Chinese star charts such as CheonSangYeolChaBunYaJiDo (天象列次分野之圖), Joseon-Butienge (朝鮮步天歌), Suzhou (蘇州) Star Chart, and Tang-Butiange (唐步天歌). Finally, we found that the shape of constellations in the flags might be similar to those in the Chinese Tang-Butienge. We also found several errors such as the shape, connecting pattern, and number of constellations drawn in the flags. It seems that the constellation flags were unofficially used in military camps in the late Joseon dynasty. Meanwhile, the 28 constellations are divided into four groups and each group has its own color and direction. We suppose that the constellation flags might represent the positions of military camps and each group of flags has their own color based on their cardinal points.

• Publications of The Korean Astronomical Society
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• v.28 no.3
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• pp.37-54
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• 2013

China and Korea have a long history of star charts, dating from the prehistoric period. Historically, Korean astronomy has been deeply influenced by China over the last two thousand years, particularly on constellation system. Therefore, Chinese and Korean traditional star charts have many similarities in terms of shape of constellation, number of star, and so forth. Korean star charts, however, have lots of unique characteristics distinguishing from Chinese ones, such as, size of star and position of constellation. Overall knowledge of the Chinese star chart is required to study the Korean star chart. In this paper, I focus on introducing selected star charts in China and Korea. Although this review is very limited, I hope that this paper is helpful in research in the field of historical astronomy.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.212-216
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• 2022

Space based constellation network is a kind of ad hoc network in which users are self-organized without center node. In space based constellation network, users are allowed to enter or leave the network at any given time. Thus, the number of active users is an unknown and time-varying parameter, and the performance of the network depends on how accurately this parameter is estimated. The so-called problem of active user identification, which consists of determining the number and identities of users transmitting in space based constellation network is discussed and a novel active user identification method is proposed in this paper. Active user identification code generated by transmitter address code and receiver address code is used to spread spectrum. Subspace-based method is used to process received signal and judgment model is established to identify active users according to the processing results. The proposed method is simulated under AWGN channel, Rician channel and Rayleigh channel respectively. Numerical results indicate that the proposed method obtains at least 1.16dB E_b/N₀ gains compared with reference methods when miss alarm rate reaches 10^-3.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.51-56
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• 2022

In space based constellation network, users are allowed to enter or leave the network arbitrarily. Hence, the number, identities and transmitted data of active users vary with time and have considerable impacts on the receiver's performance. The so-called problem of multiuser detection means identifying the identity of each active user and detecting the data transmitted by each active user. Traditional methods assume that the number of active users is equal to the maximum number of users that the network can hold. The model of traditional methods are simple and the performance are suboptimal. In this paper a Maximum A Posteriori Probability (MAP) based multiuser detection method is proposed. The proposed method models the activity state of users as Markov chain and transforms multiuser detection into searching optimal path in grid map with BCJR algorithm. Simulation results indicate that the proposed method obtains 2.6dB and 1dB E_b/N₀ gains respectively when activity detection error rate and symbol error rate reach 10^-3, comparing with reference methods.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.48.1-48.1
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• 2016

남십자자리(Crux)는 현재 북반구 중위도 지역에서는 관측할 수 없는 별자리지만 고대 중국의 전통 별자리 체계가 성립되던 시기인 춘추전국시대만 하더라도 지평선 부근에서 쉽게 관측할 수 있는 별자리였다. 우리는 세차운동 계산을 통해 남십자자리가 출몰성에서 전몰성으로 변했음을 확인하였고, 고대 중국의 문헌 기록과 성표, 성도의 별자리 그림 분석을 통해 남십자자리의 밝은 4개의 별이 중국의 전통 별자리인 고루성(庫褸星)과 일치함을 확인하였다. 또한 남십자자리가 관측되던 시기와 관측되지 않던 시기에 각각 작성되었던 성표와 성도 분석을 통해 고루성의 별자리 모양이 점차 변형되어 갔음을 제시하였다. 마지막으로 서양의 천문기술이 중국에 전해 진 이후 진행된 동서양의 별자리 상호 비교 및 동정 결과들을 분석하여 중국의 전통 별자리 체계에서 어떻게 고루성이 완전히 배제되게 되었는지에 대한 논의를 포함, 본 연구의 초기 결과들을 발표할 예정이다.

• Korean Journal of Heritage: History & Science
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• v.46 no.2
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• pp.70-95
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• 2013

The Tejaprabha Buddha painting, located in the Korai Museum in Kyoto, Japan, was made in 1569 when Joseon Dynasty was in his $14^{th}$ year under SeonJo's ruling, and is only one of Tejaprabha Buddha paintings from the early Chosun dynasty. With its well preserved state, the painting allows clear indications of all icons and list of names that were written, and the record region also has minimal deterioration. This Buddhist painting is a GumSeonMyoHwa which is drawn with gold lining on red hemp cloth and has a relatively small dimension of $84.8{\times}66.1cm$. With the Tejaprabha Buddha in the center, the painting has two unidentified Bodhisattvas, Navagrabha, Rahu, Keto, YiSipPalSoo (28 constellation of the eastern philosophy), SipYiGoong (12 zodiacs of the western philosophy), SamDaeYookSung, and BookDooChilSung (the Big Dipper), all of which provide resourceful materials for constellation worshipin the Joseon era. This painting has a crucial representation of the overall Tejaprabha Buddhism - a type of constellation worships - from the early Joseon dynasty. Even though the composition does seem to be affiliated with the paintings from the Koryo dynasty, there are meaningful transformations that reflect changes in content into constellation worship in Joseon dynasty. As a part of the Tejaprabha Buddha, SipIlYo has become a center of the painting, but with reduced guidance and off-centered 'Weolpe (star)', the painting deteriorates the concept of SipIlYo's composition. Furthermore, addition of Taoistic constellation beliefs, such as JaMiSung (The purple Tenuity Emperor of the North Pole), OkHwangDaeChae, and CheonHwangJae, eliminates the clear distinction between Taoistic and Buddhist constellation worships. Unlike the Chinese Tejaprabha Buddha painting, the concept of YiSipPalSoo (28 constellation of eastern philosophy) in this painting clearly reflects Korean CheonMoonDo's approach to constellation which can be applied to its uniqueness of the constellation worships. The fact that the Big Dipper and ChilWonSungKoon (Buddha of the Root Destiny Stars of the Northern and central Dipper) are simultaneously drawn can also be interpreted as the increase in importance of the constellation worship at the time as well.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.2
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• pp.43-55
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• 2015

In the case of satellite navigation positioning, the shielding of satellite signals is determined by the environment of the region at which a user is located, and the navigation performance is determined accordingly. The accuracy of user position determination varies depending on the dilution of precision (DOP) which is a measuring index for the geometric characteristics of visible satellites; and if the minimum visible satellites are not secured, position determination is impossible. Currently, the GLObal NAvigation Satellite system (GLONASS) of Russia is used to supplement the navigation performance of the Global Positioning System (GPS) in regions where GPS cannot be used. In addition, the European Satellite Navigation System (Galileo) of the European Union, the Chinese Satellite Navigation System (BeiDou) of China, the Quasi-Zenith Satellite System (QZSS) of Japan, and the Indian Regional Navigation Satellite System (IRNSS) of India are aimed to achieve the full operational capability (FOC) operation of the navigation system. Thus, the number of satellites available for navigation would rapidly increase, particularly in the Asian region; and when integrated navigation is performed, the improvement of navigation performance is expected to be much larger than that in other regions. To secure a stable and prompt position solution, GPS-GLONASS integrated navigation is generally performed at present. However, as available satellite navigation systems have been diversified, finding the minimum satellite constellation combination to obtain the best navigation performance has recently become an issue. For this purpose, it is necessary to examine and predict the navigation performance that could be obtained by the addition of the third satellite navigation system in addition to GPS-GLONASS. In this study, the current status of the integrated navigation performance for various satellite constellation combinations was analyzed based on 2014, and the navigation performance in 2020 was predicted based on the FOC plan of the satellite navigation system for each country. For this prediction, the orbital elements and nominal almanac data of satellite navigation systems that can be observed in the Korean Peninsula were organized, and the minimum elevation angle expecting signal shielding was established based on Matlab and the performance was predicted in terms of DOP. In the case of integrated navigation, a time offset determination algorithm needs to be considered in order to estimate the clock error between navigation systems, and it was analyzed using two kinds of methods: a satellite navigation message based estimation method and a receiver based method where a user directly performs estimation. This simulation is expected to be used as an index for the establishment of the minimum satellite constellation for obtaining the best navigation performance.

• Korean Journal of Acupuncture
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• v.36 no.4
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• pp.252-263
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• 2019

Objectives : This research aimed to 1) analyze the true meanings of the chapter, 'Wigi Haeng (Wei Qi Xing), the movement of guard qi' in Youngchu (Ling Shu) from the point of view of ancient Chinese Astronomy, 2) calculate the speed of Wigi over 24 Chinese seasons, 3) analyze the true meaning of daytime and nighttime in the chapter. Methods : 1) The chapter 'Wigi Haeng' was analyzed using concepts of ancient Chinese astronomy, 2) the records of angular distances of 28 constellations in the Book of Han (Han Shu) were used to analyze the meanings, and 3) the records of lengths of daytime and nighttime in the Book of Hou Han (Hou Han Shu) were used to calculate the speed of Wigi. Results : 1) The author of the chapter 'Wigi Haeng' did not consider the irregularity in the angular distances of the 28 Chinese constellations (Su). 2) The commentary in the Huangjenaegyong Taeso (Huang Di Nei Jing Tai Su) about the constellations in the chapter is correct. 3) The speed of Wigi changes in daytime and nighttime depending on the seasons. 4) When the speed of Wigi increases in daytime, the speed in nighttime decreases, and vice versa. 5) The beginning of daytime in 'Wigi Haeng' is not the time of sunrise but the time of dawn (2.5 Gak before sunrise). The nighttime ends 2.5 Gak after sunset. Conclusions : 1) The chapter 'Wigi Haeng' demonstrates the ancient astronomical point of view on the universe and the movement of Wigi. The speed of Wigi is variable. 2) This chapter does not address the irregularity in the angular distances of the 28 Su. 3) More research is needed on the meaning of daytime and nighttime in 'Wigi Haeng'.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.433-437
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• 1996

We have analyzed the content of the Korean stone star chart. Ch'on-Sang-Yul-Cha-Bun-Ya-Ji-Do(here-after Ch'on-Sang-Do). In the star map we have found 1468 stars, 4 more than the Chinese star catalog Bo-Chun-Ga. The four extra stars form a constellation, Jong Dae Boo. The map projection law used in the star chart is found to be the polar equtorial and equidistance projection. The linear distance of an object on Ch'on-Sang-Do from the center is linearly proportional to the north polar angular distance. We have found from a statistical analysis that most stars with declination lower than 50 are at positions representing the epoch of around the first century. On the other hand, stars near the north pole with declination higher than 50 are at the epoch of about 1300, which is close to the time the chart was engraved. This implies that the original Ko-Gu-Rye Dynasty's star chart has been revised by astronomers of Cho-Sun Dynasty. We have also shown that stars on Ch'on-Sang-Do are engraved in such a way that their area is linearly proportional to the visual magnitude.

• Journal of Astronomy and Space Sciences
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• v.26 no.3
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• pp.375-402
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• 2009

Korean historical constellations and their names are similar to Chinese ones. Although Korean historical astronomy is influenced by China, they have distinct differences in each shape and names of the constellations. We, therefore, compare Bocheonga (步天歌) of the early Joseon dynasty (朝鮮, $1392{\sim}1910$) preserved in Gyujanggark (奎章閣) with that of the Sui dynasty ((隋代, $581{\sim}618$ of China written by Wang Ximing(王希明) in terms of star charts and descriptions of the contents. We find out that the two books are partly different all over the books. First, there are definite differences in preface, three area of constellations (三垣) in the heaven, and the description of the Milky Way. Second, some of constellations show different in shape, the number of stars. Especially connecting pattern in some constellations shows different in each other. Third, Joseon Bocheonga describes their colors for some stars. These mean that Joseon has a unique tradition of star maps unlike Chinese one. We also summarize the differences and distinctive characteristics of Joseon star charts compared with Chinese ones.