• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.242-245
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• 2011

This is the first report of Japonolaeops dentatus Amaoka, belonging to the family Bothidae, collected in Korea. Four specimens (152.9~174.7 mm in standard length) were caught in the coastal waters of Jeju Island by using the bottom trawl. This species was characterized by the following morphological traits: 115~120 dorsal fin rays, 96~98 anal fin rays, 105~106 pores in lateral line, upper jaw extending to below anterior margin of lower eye, and teeth presenting on both ocular and blind sides of the jaw. We propose a new Korean name, "Geom-eun-kko-ri-neop-chi-sok" and "Geom-eun-kko-ri-neop-chi" for the genus and species, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.173-179
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• 2017

This paper analyzes actuator characteristics for main wing and tail surfaces of an ornithopter by using a motion capture test. Experiments with the ornithopter are conducted indoor, and its fuselage is held on a jig to reduce interaction with vibration generated by flapping motion. The motion capture system detects the movement of markers attached on the main wing and tail wing tip. Experimental results show that the main wings tend to change its amplitude according to the flapping frequency, and the lift and thrust generation simulation is implemented by applying the experimental results and the ornithopter specification to Modified Strip Theory. Step input excitation is applied for experimental analysis of the tail wing in horizontal and vertical directions. As a result, horizontal and vertical tail wings have different characteristics in terms of overshoot, final value, damping ratio and natural frequency because they have different wing structures and linkages.

• Research in Plant Disease
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• v.9 no.4
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• pp.221-223
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• 2003

In May 2002, a destructive stem rot of Obedient plant (Physostegia virginiana) occurred sporadically in an exhibition farm of Hamyang-gun, Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted. White mycelial mats were spread over lesions and the sclerotia were formed on the stems near soil line. The sclerotia was globoid or irregular in shape, 1${\sim}$3 mm in size, and brown in color. The optimum temperature for fungal growth was about $30^{\circ}C$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA, and hyphal diameter was 3.6${\sim}$9.4 ${\mu}m$. On the basis of mycological characteristics and test of pathogenecity to host plants, the fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of Physostegia virginiana caused by Sclerotium rolfsii in Korea.

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.260-267
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• 1998

Three species of the order Perciformes collected from coastal waters of Cheju Island, Korea were documented with photographs, all of which are newly known to Korea. Nemipterus bathybius Snyder, 1911 of the family Nemipteridae is distinguished by seven anal soft rays and the most upper ray at the caudal fin elongated. Cirrhitichthys aureus (Temminck et Schlegel, 1842) of the family Cirrhitidae (New Korean name: Hwangbokdom-kwa), is characterized by the five to six light black spots on the dorso-Iateral sides, 12 dorsal soft rays and a dorsal fin without spots and bands. Parapercis aurantiaca D$\ddot{o}$erlein, 1884 of the family Pinguipedidae, has several taxonomic characters. The dorsal spines and the soft rays of the dorsal fins were connected without a notch. The five to six dark yellow bands with the same size of eye length were shown on the lateral region. A new Korean name Kinsilkkoridom is proposed for the Nemipterus bathybius, and Cirrhitichthys aureus, Hwangbukdom, and Parapercis aurantiaca, Hwangssangdonggari.

• Korean Journal of Ichthyology
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• v.32 no.3
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• pp.136-142
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• 2020

Morphology and osteology of the slender ribbonfish, Trachipterus ishikawae was described and figured in detail. The morphological characteristics are as follow: body elongate and compressed; upper jaw protrusile; tubercles along ventral edge of body and tail; eyes are large; body naked; caudal fin long and at a right angle to the body; from (3~4)+(7~8) gill rakers; from 180 to 185 dorsal fin rays, from 12 to 13 pectoral fin rays; 9 caudal fin rays and 5+2 short spine at caudal spine. The osteological characteristics are as follow: premaxillary is long and has four teeth; dentary is triangle shape; interopercle and subopercle are wide and flat; 5 branchiostegal rays; post clavicle is thin and long; from 79 to 80 centrum; posterior vertebrae elongate; 5~6 tubercles at urostyle bone.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.274-280
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• 2014

The spermatozoa of Platichthys stellatus is relatively simple cells composed of a spherical head, a short midpiece, and a tail, as in most Pleuronectiformes. The ultrastructure is characterized by the following features: a round nucleus with a deep nuclear fossa, the centriolar complex located at a right angle to each other, a short midpiece, a tail with paired lateral ribbon and no acrosome. However there are some minor morphological differences, including the appearance and number of the mitochondria, the shape and size of the nuclear fossa and the structure of the basal body. Especially the basal body structure consisting of a basal foot, a rootlet and nine alar sheets structures varies considerably in different species. It can be used as indicator of relationships in Pleuronectiformes because minute morphological differences might have functional and evolutionary significance. In conclusion, the spermatozoa of P. stellatus show a certain structural homogeneity and provide support for the concept that ultrastructural features of spermatozoa can be useful in taxonomic studies of Pleuronectiformes.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1479-1494
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• 2015

Since the Markowitz's mean-variance framework for portfolio analysis, the topic of portfolio optimization has been an important topic in finance. Traditional approaches focus on maximizing the expected return of the portfolio while minimizing its variance, assuming that risky asset returns are normally distributed. The normality assumption however has widely been criticized as actual stock price distributions exhibit much heavier tails as well as asymmetry. To this extent, in this paper we employ the genetic algorithm to find the optimal portfolio under the Value-at-Risk (VaR) constraint, where the tail of risky assets are modeled with the generalized Pareto distribution (GPD), the standard distribution for exceedances in extreme value theory. An empirical study using Korean stock prices shows that the performance of the proposed method is efficient and better than alternative methods.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.289-297
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• 2010

The loss of natural habitats and their fragmentation caused by human activities pose a great threat to biodiversity worldwide, reducing animal population to small, fragmented patches of natural habitat. In this paper, a metapopulation dynamics of Sericinus montela koreanus, a species of butterfly, was studied for two years by mark-release-recapture (MRR) techiques in the Musimcheon, Cheongju Korea. 2,749 individuals (males: 2,295, females: 454) were marked and released, with 343 individuals (12.5%) recaptured during the MRR experiment. Capture sex ratio and recapture sex ratios was both consistently male-biased. The Jolly-Seber model was used to estimate daily metapopulation size, survival rates, addition rate, and accidental deaths. We urge conservation biologists to consider the local population dynamics of species for the management of metapopulations in fragmented landscapes. In the case of the S. montela koreanus, continuing site protection is essential.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.181-188
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• 2020

This study was conducted to identify the optimal conditions for seedling growth in Veronica rotunda var. subintegra (Nakai) T.Yamaz. which a endemic plant and can be development as ornamental plants. We sowed V. rotunda var. subintegra (Nakai) T.Yamaz. seeds, and exposed the seedling was different treatment conditions. We varied soil type and fertilizer concentration, shading ratio, additional fertilizer concentration, pretreatment light exposure and collection time of seeds. We found that seedling growth was good in horticultural substrate (with no additional fertilizer), but mixed soils supplemented with fertilizer inhibited growth, regardless of the fertilizer concentration. In the 55% shading treatment, seedling growth was greater than in the non-shading treatment. High concentration addition of fertilizer (Hyponex) promoted plant growth, in terms of both plant length and fresh weight. Exposure of seeds to a red light-source prior to germination had a greater effect on seedling growth than exposure to other light sources. Seedlings exhibited better growth when grown from seed collected in 2018, rather than 2017.

• Research in Plant Disease
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• v.9 no.1
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• pp.28-31
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• 2003

A sclerotinia rot was occurred on the stems of Obedient plant (Physostegia virginiaqna) grown in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services, Korea in 2002. The typical symptoms of the disease were that the infected leaves and stems, at first, became dark green, then watery and soft rotted, later, White fluffy mycelia formed on the lesion developed black sclerotia, later, Sclerotia formed on the plants and PDA medium were globose to cylindrical or irregular in shape and 1.0~10.3$\times$1.0~8.4 mm in size. Aphothecia were cup-shape with numerous asci and 0.8~1.8 cm in diameter, Asci were cylindrical in shape and 84~286$\times$4.7~26.3 ${\mu}{\textrm}{m}$ in size. Ascospores were one cell hyaline, ellipsoid to ovoid in shape, and 7.6~12.8$\times$3.4~6.2 ${\mu}{\textrm}{m}$ in size. The optimum temperature far mycelial growth was $25^{\circ}C$. This is the first report on the sclerotinia rot of Physostegia virginiaqna caused by Sclerotinia sclerotiorum in Korea.