• Communications of the Korean Mathematical Society
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• v.9 no.4
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• pp.905-915
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• 1994

Let $M_g$ be the moduli space of isomorphism classes of genus g smooth curves. It is a quasi-projective variety of dimension 3g - 3, when $g > 2$. It is known that a complete subvariety of $M_g$ has dimension $< g-1 [D]$. In general it is not known whether this bound is rigid. For example, it is not known whether $M_4$ has a complete surface in it. But one knows that there is a complete curve through any given finite points [H]. Recently, an explicit example of a complete curve in moduli space is given in [G-H]. In [G-H] they constructed a complete curve of $M_3$ as an intersection of five hypersurfaces of the Satake compactification of $M_3$. One way to get a complete curve of $M_3$ is to find a complete one dimensional family $p : X \to B$ of plane quartics which gives a nontrivial morphism from the base space B to the moduli space $M_3$. This is because every non-hyperelliptic smooth curve of genus three can be realized as a nonsingular plane quartic and vice versa. This paper has come out from the effort to find such a complete family of plane quartics. Since nonsingular quartics form an affine space some fibers of p must be singular ones. In this paper, due to the semistable reduction theorem [M], we search singular plane quartics which can occur as singular fibers of the family above. We first list all distinct plane quartics in terms of singularities.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.41.1-41.1
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• 2016

The Galactic center, Sagittarius A* (Sgr A*), is the closest supermassive black hole and emits synchrotron radiation. It provides great opportunity to study the origin of mm/sub-mm emission. Currently, two competing models have been suggested as a jet base and a radiatively inecient accretion flow (RIAF). To unveil the properties, the extremely high resolution(${\sim}10{\mu}as$) corresponding to the projected Schwarzschild radius of ~0.1AU is necessary. With KVN, a jet model can be tested by multi- frequency simultaneous observations because the optically thick surface in a jet (i.e. radio core) moves toward the center at a higher frequency. We conducted 8 observations with KVN at 43/86GHz in 2015, and found that the measured positional shift to the reference calibrator, J1744-3116, was ~0.3 mas to the south of Sgr A* using the source frequency phase referencing (SFPR) at Q/W bands for the first time. With the result, in the future, we will attempt to measure the variation of source position shifts that can constrain the direction of approaching jets and the variability of black hole activity of Sgr A*.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.56-64
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• 2009

This paper presents a parallel typed walking robot which can walk in omni-direction and climb from a floor to a wall. We design a six D.O.F leg mechanism composed of three legs, which form a parallel mechanism with a base and a ground to generate arbitrary poses. Optimal design is conducted to maximize the walking space and the dexterity, which are normalized by the stroke of leg. Kinematic parameters are found to maximize the weighted optimal objectives. We design a triple parallel mechanism robot by inserting Stewart platform between the upper leg mechanism and the lower leg mechanism and examine the gaits when the robot walks on the ground and climbs from a floor to a wall. The analysis of walking space and dexterity for each gait shows that the triple parallel walking robot has a large walking space with a large stability region. We explore the possibility that the robot can climb from a floor to a wall. Investigating the gaits for the six steps proves that the robot can lift the foot up to the wall by combining the orientational walking space generated by three parallel mechanisms.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.589-592
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• 2008

Running title: A plunging ranula extended into parapharyngeal space Ranulas are lesion of sublingual gland origin, which occur in the floor of the mouth. Most ranulas, whether simple or plunging, are pseudocysts without and epithelial lining and ranulas have higher levels of salivary amylase and protein content. They can be classified into two types based on their extent: simple ranulas, confined to the sublingual space and plunging ranula which extend into adjacent spaces. Plunging ranula requires differential diagnosis with other lesions (neuroma, monomorphic adenoma, hemangioma, lipoma, dermoid cyst, lateral cervical cyst). The patient was diagnosed as plunging ranula. We experienced 17 years old male, visited to our department, who complain Rt. cervical swelling and in MRI view, this lesion involved sublingual, submadibular, parapharyngeal, skull base. We experienced a rare case of plunging ranula, extended into parapharyngeal space. We report the case.

• Korean Institute of Interior Design Journal
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• v.18 no.1
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• pp.89-98
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• 2009

As the quality of life Increases, most people are much interested in their health. The latest knowledge and concepts are newly employed and consistently extended in the field of medical facilities as well. The purpose of this study is to investigate space-structural features of dental clinics, to analyze space components in two aspects, the function and the moving path, to provide with base materials for interior design research, and, as a result, to contribute to the improvement of dental clinics. The visitor survey method was implemented in five dental offices haying opened since 2000. The survey results show that each area is distributed as follows; the consultation room is the largest, the waiting space is secondly largest, and the facility area of medical assistance and administration is the smallest. The consultation space can be designed as semi-opened or opened. Considering moving paths, each should not be too long for the communication between doctors and patients, and for the effective medical examination and treatment. The survey indicates medical assistants have the longest moving path because they fully utilize every space. Based on the survey results described above, more systematic in-depth studies should be performed in the future.

• Journal of Korean Society of Rural Planning
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• v.15 no.1
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• pp.1-13
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• 2009

This study tried to establish a renewal guideline for rural villages through the analysis on locational characteristics of amenity/disamenity elements. Space Syntax Method was applied to analyze the locational characteristics of amenity/disamenity elements in qualitative terms. The study was carried out by 5 steps: Selection of amenity/disamenity classification table and case study villages(used same ones as in the previous study) ${\rightarrow}$ Drawing of base-map for spatial analysis ${\rightarrow}$ Preparation of final study-map after field survey ${\rightarrow}$ Spatial analysis using the Space Syntax Method ${\rightarrow}$ Proposing of a rural village renewal guideline. Through the application study to the case study villages, it was ascertained that the renewal guideline proposed in this study would well help reflect spatial characteristics of amenity/disamenity elements in plan-making works of rural villages.

• Architectural research
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• v.22 no.4
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• pp.155-162
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• 2020

Numerous scholars have explored the modeling, control, and optimization of energy systems in buildings, offering new insights about technology and environments that can advance industry innovation. Eye trackers deliver objective eye-gaze data about visual and attentional processes. Due to its flexibility, accuracy, and efficiency in research, eye tracking has a control scheme that makes measuring rapid eye movement in three-dimensional space possible (e.g., virtual reality, augmented reality). Because eye movement is an effective modality for digital interaction with a virtual environment, tracking how users scan a visual field and fix on various digital objects can help designers optimize building environments and materials. Although several scholars have conducted Virtual Reality studies in three-dimensional space, scholars have not agreed on a consistent way to analyze eye tracking data. We conducted eye tracking experiments using objects in three-dimensional space to find an objective way to process quantitative visual data. By applying a 12 × 12 grid framework for eye tracking analysis, we investigated how people gazed at objects in a virtual space wearing a headmounted display. The findings provide an empirical base for a standardized protocol for analyzing eye tracking data in the context of virtual environments.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.42.3-42.3
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• 2019

We translate Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) ultraviolet (UV) multi-channel images into another UV single-channel image using a deep learning algorithm based on conditional generative adversarial networks (cGANs). The base input channel, which has the highest correlation coefficient (CC) between UV channels of AIA, is 193 Å. To complement this channel, we choose two channels, 1600 and 304 Å, which represent upper photosphere and chromosphere, respectively. Input channels for three models are single (193 Å), dual (193+1600 Å), and triple (193+1600+304 Å), respectively. Quantitative comparisons are made for test data sets. Main results from this study are as follows. First, the single model successfully produce other coronal channel images but less successful for chromospheric channel (304 Å) and much less successful for two photospheric channels (1600 and 1700 Å). Second, the dual model shows a noticeable improvement of the CC between the model outputs and Ground truths for 1700 Å. Third, the triple model can generate all other channel images with relatively high CCs larger than 0.89. Our results show a possibility that if three channels from photosphere, chromosphere, and corona are selected, other multi-channel images could be generated by deep learning. We expect that this investigation will be a complementary tool to choose a few UV channels for future solar small and/or deep space missions.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.17-24
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• 2022

This study aims to identify the Spatial Changes and the main agent of space creation in Samrye Area during the Japanese Occupation Period. As for the urban space in the Samrye area, the urban space was expanded to the Hujeong-ri area from the construction of the Jeonbuk light railway. Before 1914, the urban space of Samrye was formed around Samrye Station in Samrye-ri, which oversees Samrye-do from the Goryeo Dynasty to the Joseon Dynasty, but when Samrye Station of Jeonbuk light railway was established in Hujeong-ri in 1914, the foundation of a ladder-type street network visible from the central space of the current Samrye area was formed until the 1930s. And it was the Japanese and Korean landowners who took the lead in the construction of the Jeonbuk light railway, not the government, who expanded the urban space of Samnye from Samrye-ri to Hujeong-ri. The background of the establishment of Jeonbuk light railway is the reason why Dongsan Farm has difficulty in transporting rice to the Honam Line during the rice harvest. At that time, Park Ki-soon, famous as the land king, took charge of the established chairman of the railroad installation and established it, and with the establishment of Samrye Station, the access road was connected to his farm. In addition, a new road was built on the farm land that owned the Hujeong-ri area to the Seoul-Mokpo Interroad in Samrye-ri, thereby expanding the urban space. In other words, unlike Gunsan and Iksan, which were built under the leadership of the Japanese colonial eran government, the urban space in Samrye area was expanded by a farmer who grew up as a large landowner based on agriculture, which was the economic base at the time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.131-138
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• 2023

In this paper, a free space optical communication device that can be used in a mobile base station of several km or less was fabricated and its characteristics were investigated. To overcome the loss due to atmospheric transmission, an optical fiber amplifier (EDFA) with an output of 23 dBm or more was used. In order to increase the focusing speed and miniaturization of the laser beam, an optical lens was manufactured, and a transmission lens was designed to have beam divergence within the range of 1.5 to 1.8 [mrad]. A PT module that controls PAN/TILT was fabricated in order to reduce pointing errors and effective automatic alignment between transceiver devices. In this study, Reed-Solomon (RS) code was used to maintain the transmission quality above a certain level. It was manufactured to be able to communicate at a wireless distance of 300m in a weather situation with visibility of 300m. For performance measurement, it was measured using BERT and eye pattern analyzer, and it was confirmed that BER can be maintained at 2.5Gbps.