A new Hibiscus cultivar ‘Woolred’ having vigorous growth, uniform plant habit, upright, compact branches, and unique flower shape was developed through interspecific crosses between H. sinosyriacus ‘Seobong’ (♀) and H. syriacus ‘Samchully’ ( ♂ ). Hibiscus breeding program was initiated in 2002 and Hibiscus × ‘Woolred’ was preliminarily selected as ‘R-161’ in 2004 due to its vigorous growth and stable flower quality with rich pink flower. The selected line was further evaluated for different growth characteristics such as leaf shape, leaf size, flowering characteristics, and tested for distinctness, homogeneity, and stability during 2007-2009. The new cultivar ‘Woolred’ had violet pink color flower (RHS N74C) with red eye spot, medium in size having fan petals. The size of flower was 11.5 cm and size of red eye was 3.2 cm. Leaves were 7.7 cm long and 4.2 cm wide. After the plant characteristics evaluation for 3 years (2007 ~ 2009), it was registered as a cultivar ‘Woolred’ (3702, No. of plant variety protection rights) in 2011. This newly developed cultivar ‘Woolred’ having vigorous growth and unique flower shape can be used as specimen plant in landscape.

In this study, the internal structure of a Heumgyeonggak-nu (欽敬閣漏) was designed, and the power transmission mechanism was analyzed. Heumgyeonggak-nu is an automated water clock from the Joseon Dynasty that was installed within Heumgyeonggak (欽敬閣), and it was manufactured in the 20th year of the reign of King Sejong (1438). As descriptions of Heumgyeonggak-nu in ancient literature have mostly focused on its external shape, the study of its internal mechanism has been difficult. A detailed analysis of the literature record on Heumgyeonggak-nu (e.g., The Annals of the Joseon Dynasty) indicates that Heumgyeonggaknu had a three-stage water clock, included a waterfall or tilting vessel (欹器) using the overflowed water, and displayed the time using a ball. In this study, the Cheonhyeong apparatus, water wheel, scoop, and various mechanism wheels were designed so that 16 fixed-type scoops could operate at a constant speed for the water wheel with a diameter of 100 cm. As the scoop can contain 1.25 l of water and the water wheel rotates 61 times a day, a total of 1,220 l of water is required. Also, the power gear wheel was designed as a 366-tooth gear, which supported the operation of the time signal gear wheel. To implement the movement of stars on the celestial sphere, the rotation ratio of the celestial gear wheel to the diurnal motion gear ring was set to 366:365. In addition, to operate the sun movement apparatus on the ecliptic, a gear device was installed on the South Pole axis. It is expected that the results of this study can be used for the manufacture and restoration of the operation model of Heumgyeonggak-nu.