• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.608-612
• /
• 2009

Technology demonstration models(TDM) of a 75-$ton_f$ liquid rocket engine(LRE) thrust chamber were manufactured on the basis of development technologies of 30-$ton_f$ LRE. It was confirmed that some machining and welding technologies which were aimed to be verified through the manufacturing of demonstration models could be applied to the thrust chamber 75-$ton_f$-class. New designed mixing head part was manufactured by means of new process. The manufacturing process and technologies established through TDM's will improve the reliability of manufacturing process of large LRE thrust chamber.

• Wind and Structures
• /
• v.17 no.5
• /
• pp.479-494
• /
• 2013

The vehicle-induced aerodynamic loads bring vibrations to some of the highway sound barriers, for they are designed in consideration of natural wind loads only. As references to the previous field experiment, the vehicle-induced aerodynamic loads is investigated by numerical and theoretical methodologies. The numerical results are compared to the experimental one and proved to be available. By analyzing the flow field achieved in the numerical simulation, the potential flow is proved to be the main source of both head and wake impact, so the theoretical model is also validated. The results from the two methodologies show that the shorter vehicle length would produce larger negative pressure peak as the head impact and wake impact overlapping with each other, and together with the fast speed, it would lead to a wake without vortex shedding, which makes the potential hypothesis more accurate. It also proves the expectation in vehicle-induced aerodynamic loads on Highway Sound Barriers Part1: Field Experiment, that max/min pressure is proportional to the square of vehicle speed and inverse square of separation distance.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.1
• /
• pp.67-71
• /
• 2019

With continued technology innovation in the fields of computer graphics (CG) and virtual reality (VR), digital animated avatars (or virtual humans) are evolving into ones that are more interactive at a suitable location such as museum, airport, and shopping mall. Specially, the form of the avatar (or the virtual human) realistically need to be expressed in a way that matches the users' physical space. In recent many researches, the form of virtual human has been expressed as mixed-reality human (MRH)-the virtual human combines with the physicality as the real part. In this paper, we propose to carry out a study comparing various MRH on co-presence and emotional response in two-typed virtual humans depending on how many actual parts are included: (1) (Level 1) small parts in the virtual human combined virtual components (e.g., the head only) and (2) (Level 2) large parts in the virtual human with the physicality as the real part such as head, arms, and upper body). We report on the implemented results of our virtual humans and experimental results on co-presence and emotional response.

• Journal of Auto-vehicle Safety Association
• /
• v.13 no.1
• /
• pp.45-50
• /
• 2021

This study aimed to verify the criteria of the driver monitoring systems proposed by UNECE ACSF informal working group and the ministry of land, infrastructure, and transport of South Korea using driving behavior data. In order to verify the criteria, we investigated the safety regulations of driver monitoring systems in a conditional autonomous vehicle and found that the driver monitoring measures were related to eye blinks times, head movements, and eye closed duration. Thus, we took two different experimental data including real-world driving and simulator-based drowsy driving behaviors in previous studies. The real-world driving data were used for analyzing blink times and head movement intervals, and the drowsiness data were used for eye closed duration. In the drowsy driving study, 10 drivers drove approximately 37 km of a monotonous highway (about 22 min) twice. The results suggested that the appropriate duration of eyes continuously closed was 4 seconds. The results from real-world driving data were presented in the other paper - part 1.

• Fisheries and Aquatic Sciences
• /
• v.24 no.5
• /
• pp.181-190
• /
• 2021

Grouper is one of the most economically important fishes with various morphological forms and characteristics, meaning it is often difficult to identify species and distinguish between life stages, sometimes leading to morphological misidentification. Therefore, identification using a molecular deoxyribose nucleic acid (DNA) approach was needed as an alternative means to identify closely related species. This study aims to determine the molecular phylogeny of grouper from the northern part of the Bird's Head Seascape of Papua. The DNA sequence of each cytochrome oxidase I (COI) gene was used to study the molecular relationship among closely related species of grouper. The results showed that there were 16 Epinephelinae that have been compared to a gene bank (National Centre for Biotechnology Information, NCBI) in the sequence length of 623 base pairs. The closest genetic distance was found between Cephalopholis miniata and Cephalopholis sexmaculata (0.036), while the furthest genetic distance was observed between Plectropomus laevis and Cephalopholis spiloparaea (0.247). This finding was further reinforced by the morphological characters of each species. This finding highlighted that five genera were represented as a monophyletic group (clade), i.e., Epinephelus, Cephalopholis, Plectropomus, Saloptia and Variola.

• Journal of the Korean Society of Costume
• /
• v.37
• /
• pp.47-69
• /
• 1998

The purpose of this study is to inquire the hair, head-dress and clothing(upper clothing: Veil, Samkaksika, Sash) of Bodhisattvas in Dunhuang Mogaoku of the period from Northern Liang Dynasty(421∼439) to Tang Dynasty(618∼907). The method of this figure and the change of clothing form : 'Dunhuang Mogaoku'1st Volume-4th Volume. The Bodhisattvas' hair style are somehat various ; A part in her hair, Suibal, Gae, Sakbal. A part in Bodhisattvas's hair is observed from Northern Liang Dynasty to Sui Dynasty. But Suibal had been continuous succeeded. Meanwhile, in the periods of Sui and Tand Dynasty, there were the hair styles whose ends were curled up. It is called Eulle Meor-ee. Especially, in Tang Dynasty various styles of Gae were appeared. Doogun was observed from Northern Wei to Tang Dynasty. There were three kinds of head-dress; Samsikkwan(having 3 decoration), Bokwan and Jungmeunkwan(appeared in Tang Dynasty). Meanwhile, Sash let was become more and more decorative. The Upper clothing can be classify into Veil, Samkaksika, Sash, etc. Veil were observed in every period but X shaped one was form Northern Wei and U shaped one was from Northern Zhou Dynasty. After the period of Sui Dynasty U shaped Veil become prevalent. Samkaksika was observed for the first time in Northern Zhou Dynasty. Cutted sam-kaksika was appeared in Sui Dynasty and succeeded to Tang Dynasty. Poncho tyed Samkaksika was also observed in Tang Dynasty. In Westhern Wei Dynasty. daesupo was used into outter garment, which us that chinese influence was deep tell. Sash showed up in Tang Dynasty and it is used for Veil for the whole period of the Dynasty. But using sash for veil was formally hanged on going the lated period of Tang Dynasty. We can observe the sun-moon decoration and the wings of a bird decoration at the Bokwan, Veil, Samkaksika and Sash, etc. It is was the influendce of Sasan Per-sia and India. I will fill up the insufficency of this study wity continous research of ornament(Muktahara) and skirt of Bodhisattva and deeper inquiry of the relationship around the many countries.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.37 no.6
• /
• pp.478-484
• /
• 2004

On 11 June 1991, eggs from the brood stock of small yellow croaker (Larimichthys polyactis) were artificially fertilized using the standard dry method and were hatched. Each of the fertilized eggs (1.1-1.2 mm in diameter) had an oil globule and was transparent and buoyant. The fertilized eggs hatched in a range of water temperatures $(17.5-20.3^{\circ}C)$ 44 hrs after fertilization. The total lengths of the newly hatched larvae were 3.1-3.3 mm, and these hatchlings had 31 myotomes (10+21). Melanophores and yellow-brown chromatophores were concentrated on the head, at the ventral part of the yolk, and in the middle of the tail. Four days after hatching, the larvae completely absorbed the yolk and became flexions of 5.1-5.5 mm in total length. Fifteen days after hatching, one spine (the anterior tip of the maxillary) appeared in the upper jaw and three spines developed at the upper parts of the eyes and on the posterior part of the head. At this stage, the larvae were approximately 8.3 mm long. Thirty-nine days after hatching, juveniles (1.9-3.4 mm in total length) had a pointed tail fin. By 66 days after hatching, the juvenile fish (about 4.0-6.5 mm in total length) were similar to adult fish in body shape. The larvae of L. polyactis could be distinguished from those of L. croacea by two distinct characteristics: the large number of vertebrae (28-29), and a relatively small bony ridge on the occipital region of the head.

• Korean Journal of Ichthyology
• /
• v.18 no.3
• /
• pp.193-201
• /
• 2006

We researched the reproductive ecology of pale chub, Zacco platypus that inhabits Gajeong-cheon and Wonju-cheon that are a tributary to the Han river. The nuptial organ was formed on the head part, the anal fin and the tail part in male, the change of nuptial color was outstanding. By their changing body shape, the anal fin was extended and body depth came to be high during the spawning season in both sexes. Territorial male of defending behavior were head butting, rotated fighting, parallel swimming, biting and expelling. After pale chub located himself from the upper of the female that was approached to the side parallelling with the female, male and female spawned digging sand with their anal fin by vibrating and any parental care of the eggs was not taken. The spawning interval and lasting time were relevant to individuals density of spawning ground.

• Design & Manufacturing
• /
• v.13 no.2
• /
• pp.1-5
• /
• 2019

In this study, micro cellular injection molding of automobile head lamp housing with uneven thickness structure was performed to obtain improvement on deformation and light-weight of the part. The thickness of the presented model was uniformly modified to control the deformation of the molded part. In order to maximize the lightweight ratio, the model having an average thickness of 2.0 mm were thinly molded to an average thickness of 1.6 mm. GFM(Gas Free Molding) and CBM(Core Back Molding) technology were applied to improve the problems of the conventional foam molding method. Equal Heat & Cool system was also applied by 3D cooling core and individual flow control system. Warpage of the molded parts with even cooling was minimized. To improve the mechanical properties of foamed products, complex resin containing nano-filler was used and variation of mechanical properties was evaluated. It was shown that the weight reduction ratio of products with light-weighted injection molding was 8.9 % and the deformation of the products was improved from the maximum of 3.6 mm to 2.0 mm by applying Equal Heat & Cool mold cooling system. Also the mechanical strength reduction of foamed product was less than 12% at maximum.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.26 no.2
• /
• pp.127-129
• /
• 2015

Background and Objectives : The etiology of globus pharyngeus remains uncertain. It has been known there is a relationship between the presence of air bubbles in esophagus and GERD symptoms. The aim of this study is to identify relationship between the globus symptom and the presence of air column in esophagus. Subjects and Methods : The study population consisted of 46 patients who underwent CT scan as part of evaluation for globus. Controls were chosen from the population consisted of patients with lymphadenopathy who underwent CT scan. The correlation between the presence of globus symptom and diameter, volume, and position of the air column was assessed using t-test. Reproducibility of diameter and volume of the esophageal air column was analyzed using intraclass correlation coefficient. Results : In study group, the mean volume of the air column was $769.56{\pm}983.08mm^3$, the mean diameter was $8.24{\pm}4.90mm$, the mean distance from the inferior border of posterior lamina of cricoid cartilage was $88.86{\pm}28.01mm$. In control group, $682.18{\pm}767.28mm^3$, $8.37{\pm}5.50mm$, $88.34{\pm}21.06mm$, respectively. There were no differences of diameter, volume and distance of the air column between the two groups. We failed to obtain acceptable reliability when we compare the diameter and the volume of the esophageal air column. Conclusion : There was no relationship between air column of esophagus and presence of globus symptom. And the measurement of diameter and volume of the esophageal air column change over time and it should be considered in a further study.