• Journal of Information Technology Services
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• v.8 no.1
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• pp.11-27
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• 2009

Recently, IPTV attracts great attention along with the digital convergence of communication and media technologies. This study examined critical factors on the consumer's continued use of the IPTV service. Based on the expectation-confirmation theory and the innovation diffusion theory, we derived nine key factors in the research model-relative advantage, compatibility, ease of use, image, diversity of contents, interactivity, monetary value, social influence, and user satisfaction. Using the partial least square method, we found that content diversity and compatibility have a significant indirect effect on the continued use of the IPTV service via user satisfaction, and user satisfaction and social influence also have a significant direct impact on the IPTV use. These findings not only provide practical insights on the consumer acceptance of new technology-converging services, but also help managers to plan their marketing strategies better.

• Communications of the Korean Mathematical Society
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• v.16 no.3
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• pp.459-485
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• 2001

The aim of EIT (electrical impedance tomography) system is to image cross-section conductivity distribution of a human body by means of both generating and sensing electrodes attached on to the surface of the body, where currents are injected and voltages are measured. EIT has been suffered from the severe ill-posedness which is caused by the inherent low sensitivity of boundary measurements to any changes of internal tissue conductivity values. With a limited set of current-to-voltage data, figuring out full structure of the conductivity distribution could be extremely difficult at present time, so it could be worthwhile to extract some necessary partial information of the internal conductivity. We try to extract some key patterns of current-to-voltage data that furnish some core information on the conductivity distribution such s location and size. This overview provides our recent observation on the location search and the size estimation.

• Journal of Ginseng Research
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• v.18 no.1
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• pp.53-59
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• 1994

To develop the methodology of the quantitative analysis of saponin in ginseng milk, conditions of the saponin extraction were optimized using the fractional factorial design with 3 variables and 3 levels by a RSM computer program. The extraction of saponin increased with an increase in extraction temperature up to $90^{\circ}C$ and then decreased significantly at $100^{\circ}C$. Extraction time affected the saponin yield in a similar trend. On the other hand, decreasing cooling temperature increased the amount of the saponin extracted. Recovery yield of the saponin from ginseng milk varied from 70.0% to 92.9%. The optimum extraction temperature, time and cooling temperature determined by partial differentiation of the model equation were $86^{\circ}C$, 2.83 hrs and $4^{\circ}C$, respectively. Key words Ginseng milk, saponin, response surface methodology.

• Journal of The Korean Astronomical Society
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• v.54 no.5
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• pp.157-170
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• 2021

We investigate flow and magnetic structure of a solar prominence with a focus on how the magnetic field originally determined by subsurface dynamics gives rise to the structure. We perform a magnetohydrodynamic simulation that reproduces the self-consistent evolution of a flow and the magnetic field passing freely through the solar surface. By analyzing Lagrangian displacements of magnetized plasma elements, we demonstrate the flow structure that is naturally incorporated to the magnetic structure of the prominence formed via dynamic interaction between the flow and the magnetic field. Our results explain a diverging flow on a U-loop, a counterclockwise downdraft along a rotating field line, acceleration and deceleration of a downflow along an S-loop, and partial emergence of a W-loop, which may play key roles in determining structural properties of the prominence.

• Journal of The Korean Astronomical Society
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• v.52 no.4
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• pp.89-97
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• 2019

We demonstrate the subsurface origin of the observed evolution of the solar active region 10930 (AR10930) associated with merging and breakup of magnetic polarity regions at the solar surface. We performed a magnetohydrodynamic simulation of an emerging magnetic flux tube whose field-line twist is asymmetrically distributed along its axis, which is a key to merging and fragmentation in this active region. While emerging into the surface, the flux tube is subjected to partial splitting of its weakly twisted portion, forming separate polarity regions at the solar surface. As emergence proceeds, these separate polarity regions start to merge and then break up, while in the corona sigmoidal structures form and a solar eruption occurs. We discuss what physical processes could be involved in the characteristic evolution of an active region magnetic field that leads to the formation of a sunspot surrounded by satellite polarity regions.

• Korea Trade Review
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• v.44 no.6
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• pp.69-85
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• 2019

Logistics outsourcing businesses consist of the three main stages of bidding, contracting, and operations. This study focuses on the impacts of factors in the logistics outsourcing stages on outsourcing performance. Key factors in each stage may have direct influences on logistics partnerships and performance. Also, factors of each stage may impact the factors of subsequent stages. The relationships were examined using a structural equation model and verified by PLS (partial least square)-SEM methodology. Study results were as follows. First, the uncertainty of the shipper in the bidding phase affects the flexible contract in the contracting phase, and thus, affects the satisfaction of the logistics outsourcing services. Second, the uncertainty of the shipper in the bidding phase affects operations through contracts, and positively affects logistics outsourcing satisfaction through trust and cooperation.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.65.2-65.2
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• 2003

88 selective COX-2 inhibitors belonging to three chemical classes (triaryl rings, diaryl cycloalkanopyrazoles, and diphenyl hydrazides) were studied using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). Partial least squares analysis produced statistically significant models with q values of 0.84 and 0.79 for CoMFA and CoMSIA, respectively. The key spatial properties were detected by careful analysis of the isocontour maps. The binding energies calculated from flexible docking correlated with inhibitory activities by the least-squares fit method. (omitted)

• Journal of Species Research
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• v.12 no.1
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• pp.27-37
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• 2023

Kushia zosteraphila Harris V.A. & Iwasaki, 1996 is newly collected and described from macroalgae in the intertidal region of Gijang-gun, along the southeastern coastal region of Korea. Kushia zosteraphila can be distinguished from congeners by following morphological characteristics: the length of the first dorsal seta similar with the second dorsal seta of female P5, the length to width ratio of the female caudal ramus, and the presence of a conspicuous comb on the accessory lobe of the male antennule. Although there are some minor discrepancies, the main diagnostic characteristics of the specimen from the study area are well-matched with the original description. We herein provide detailed morphological descriptions and illustrations of this species. According to a survey of the location of the reported porcellidiid species in Korea, this specimen is the second record in Korean waters of the genus Kushia. A key to species of the family Porcellidiidae in Korea is provided. A partial sequence of the mitochondrial COI gene was obtained and provided as a DNA barcode for this species.

• Animal Systematics, Evolution and Diversity
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• v.39 no.4
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• pp.284-288
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• 2023

In this article, a phyllidiid nudibranch which is distributed widely in the Indo-Pacific region, Phyllidia varicose Lamarck, 1801, is reported based on a specimen collected from Seopseom Islet, Jeju Island, Korea. This species is characterized by bluish-gray dorsal tubercles with a yellow cap and three distinct ridges consisting of dorsal tubercles going from the anterior to posterior region, the presence of bluish-black pigment between the dorsal ridges, and a characteristic black longitudinal stripe along the midline of the sole. In this study, we provide a key to species belonging to the genus Phyllidia discovered in Korea, the morphological descriptions, photographs, and a sequence of partial mitochondrial cytochrome c oxidase subunit I of P. varicosa. Currently, four species of the genus Phyllidia have been reported to be present in Korea, including P. varicosa.

• IMMUNE NETWORK
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• v.24 no.1
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• pp.5.1-5.19
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• 2024

The key role of T cells in cancer immunotherapy is well established and is highlighted by the remarkable capacity of Ab-mediated checkpoint blockade to overcome T-cell exhaustion and amplify anti-tumor responses. However, total or partial tumor remission following checkpoint blockade is still limited to only a few types of tumors. Hence, concerted attempts are being made to devise new methods for improving tumor immunity. Currently, much attention is being focused on therapy with IL-2. This cytokine is a powerful growth factor for T cells and optimises their effector functions. When used at therapeutic doses for cancer treatment, however, IL-2 is highly toxic. Nevertheless, recent work has shown that modifying the structure or presentation of IL-2 can reduce toxicity and lead to effective anti-tumor responses in synergy with checkpoint blockade. Here, we review the complex interaction of IL-2 with T cells: first during normal homeostasis, then during responses to pathogens, and finally in anti-tumor responses.