• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.1001-1009
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• 2023

Flow is a concept closely related to intrinsic motivation and is considered a positive factor in sports performance in sports psychology. The purpose of this study was to confirm the addictive nature of Flow through previous studies and propose a new hypothesis that Flow may decrease intrinsic motivation in the long term, unlike previous studies. In line with adaptation level theory and the law of diminishing marginal utility, the satisfaction derived from Flow is continuously decreasing. At some point, the individual's progress is limited and they reach a point where they no longer experience FLOW. However, the individual will continue to try because the desire to experience FLOW again exists. However, failure to experience FLOW and repeated failure will lead to sadness, which will decrease intrinsic motivation.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.511-521
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• 2020

The purpose of this study is to research the effects of the same brand item sold online at different prices. To that end, the exploratory study is focused on four factors that influence price dispersion online is suggested. First, the products are divided into utilitarian products and hedonic products in line with the product concept, and laptops, washing machines are included in the utility concept products. Also the backpacks and sneakers are included in the hedonic concept products. A total of 400 effective objectives were selected and analyzed for each concept products, 200 objectives. The research analysis revealed that the price dispersion is significant relationship with an average price, the highest price, the lowest price, the year of release, the number of retailers, and the number of reviews in case of the utility concept product. On the contrary, in case of hedonic concept products, average price, highest price, lowest price, year of release, retailer, and reviews and ratings is found to be positively related to price dispersion. Based on these results, theoretical and practical implications are discussed about the influence price dispersion on marketing.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.143-150
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• 1987

To assess the analytic performance of immunoradiometric TSH assay (IRMA TSH), assay precision determined by intra and interassay variance, assay accuracy determined by dilution and recovery study, were evaluated by using two commercial kit $(Abott^{(R)}\;and\;Daichi^{(R)})$. Normal range of basal serum TSH and TRH stimulated TSH increment were also determined in 234 healthy subjects (male 110, female 124; age 20-70) and 30 voluteers (male 10, female 20; age 21-26). In addition, basal TSH levels of 70 patients with untreated hyperthyroidism, 50 untreated hypothyroidism, and 60 euthyroidism were measured to assess the clinical utility of IRMA TSH. The detection limit of IRMA TSH was 0.04 mU/l and 0.08 mU/l by Abott Kit and Daichi kit respectively. Using Abott kit, intra assay variance were 2.0, 3.1 and 1.4% in mean TSH concentration 2.4, 31.6 and 98.2 mU/l repectively and interassay variance were 2.0 and 3.2% in mean TSH concentration 2.3 and 31.3 mU/l. Mean recovery rate was 92.5% and dilution study showed nearly straight line. When Daichi kit was used, intrasssay variance were 5.6, 5.2 and 6.2% in mean TSH concentration of 2.4, 31.6 and 98.2 mU/l respectively and interassay variance were 7.1 and 7.4% in mean TSH of 2.3 and 31.3 mU/l. Mean recoveray rate was 89.9%. Normal range of basal TSH and TRH stimulated peak TSH were 0.38-4.02 mU/l and 2.85-30.8 mU/l repectively (95% confidence interval, Abott kit used). Sensitivity and specificity of basal TSH levels for diagnosing hypothyroidism as well as specificity for diagnosing hyperthyroidism were 100% by using both kit. Sensitivity of basal TSH level for diagnosing hyperthyroidism was 100% when TSH levels were measured by Abott kit while that was 80.9% when measured by Daichi kit. These results suggest that IRMA TSH was very precise and accurate method and might be used as a first line test in the evaluation of thyroid function.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.2
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• pp.91-111
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• 2024

Most of utility cable tunnels are constructed utilizing shield TBM as part of the underground transmission line project. The TBM chamber is the only space inside the tunnel that encounters rock and soil, and is the place with the highest frequency of accident exposure, such as collapse and collision accidents. Since there is currently no way to measure the disc cutter wear from outside the chamber, frequent inspection by workers is essential. Accordingly, in this study, in order to prevent safety accidents inside the TBM chamber and expect the effect of shortening the construction period by reducing the number of chamber openings, the concept of disk cutter wear measurement technology was established and a prototype was produced. By considering prior technology and determining that magnetic sensors are most suitable for the excavation environment, wear measurement sensor package were developed integrating magnetic sensors, wireless communication modules, power supply, external casing, and monitoring systems. To verify the performance of the prototype in an actual excavation environment, a full-scale tunnelling test was performed using a 3.6 m EPB shield TBM. Based on the full-scale tests, five prototypes were operated normally among eight prototypes. It was analyzed that sensor measurement, wireless communication, and durability performance were secured within a maximum thrust of 3,000 kN and a rotation speed of 1.5 RPM.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.269-273
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• 1998

To clarify the clinical utility of the calvarial bone graft in the maxillofacial reconstruction, we performed on anatomical study by measuring the regional thickness of the parietal bone on 17 Korean adult dry skulls. Before the sectioning the calvarium, the anatomical landmarks were marked on each specimens. And then we measured the total thickness of the parietal bone, the thickness of the outer and inner cortical plates on various points in each sections of parietal bones using a digital caliper under the stereomicroscope. The total thickness of the parietal bone was ranged from 5.17mm to 7.50mm, and there were no statistical difference in the total thickness of the parietal bone on the same points bilaterally. But there was a tendency that the thickness of the parietal bone was thicker toward to the lambda point than the coronal suture area. At the other hand, the thickness of the outer and inner plate of the parietal bone was the thickest at the first point of the right aspect on the line 1, the first point of the left aspect on the line 5, respectively. In conclusion, this study showed that the donor site of the parietal bone for the maxillofacial reconstruction should be located at more posterior and medial area of the parietal bone than the prevalent known donor site.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.9
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• pp.433-440
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• 2002

The addition of switches to a distribution feeder does, in general, increase reliability by decreasing the duration of the outage of many to the customers on the feeder. To cover its service area so that feeder-level delivery reaches sufficiently close to all customers, feeders typically split their routes many times, in what is often called a lateral feeder. It is interesting to note, however, that the effectiveness of a switch is very much dependent on the types of lateral feeder. The types of lateral are classified into two types. The first is loop lateral feeder that can connect its load to an adjacent feeder through a tie line in case that a fault occurs in its feeder and it is laid out so that every feeder has complete fault backup through re-switching of its loads to other sources like a main feeder The second is the radial lateral feeder cannot connect its load to an adjacent line, no provision is made for contingency backup of feeders. There are no other circuits in the radial lateral feeder form which to restore power. In this study, we evaluate the effectiveness of a switch installation between on the radial and loop lateral feeders to increase reliability by decreasing the duration of the outage. These results can help power utility to design the switch layouts on the radial and loop lateral feeder system.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.320-329
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• 2010

As software producers have tried to keep their profit against illegal piracy, contents producers also want to protect their contents from unlawful sharing among users. Some researchers uncovered that the regulation on the unlicensed contents is not the best policy to maximize their profit mainly due to network effect but this issue has been still controversial. In this paper, we develop a model to investigate the effect of regulation against unlicensed contents sharing on the profit of contents producers and present the optimal condition to maximize profit of contents producers under the regulation and non-regulation of unlicensed contents. As a result, we analyzed that the firm's payoff under the regulation on unlicensed contents is not always greater than the payoff under the non-regulation because of network externality. If the additional utility from off-line purchase of type P consumers (who enjoy the additional benefit of off-line purchase) is large enough, then the firm's payoff is maximized without regulation.

• Journal of Korean Society of Steel Construction
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• v.13 no.1
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• pp.1-8
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• 2001

The purpose of this study is to examine the utility of concretefilled steel tubular column to H-beam connections with tubular stiffener. As a preliminary step. a tensile experiment was undertaken to scrutinize characteristics of the structural behavior that take place between beam flanges and column with tubular stiffener. A total of 4 types of experimental settings were developed as tabular stiffeners are made up 9, 18, and 27 mm of thickness and 50 and 80 mm of height respetively Along with the overall load subsequently the degree of displacement and strain were recorded. Based on the yield line theory results of this of this study were evaluated and further critically reviewed the applicability of the strength formula. This study found that collapse mechanism was emerged on the beam flange as reinforcing tabular stiffeners Complementary studies of this sort, including numerical analyses should be undertaken in order to develope specific design critera.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.315-321
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• 2016

Background: Herbal medicine has becoming a potential source of treatment for different types of cancer including breast cancer. It has been shown that plants from the family Rhamnaceae possess anticancer activity. Objective: In this study, we determined the antiproliferative influence of Ziziphus spina christi- a species from this family- on the MCF-7 (human breast adenocarcinoma) cell line. Materials and Methods: The cytotoxicity of the total extract, ethanol, ethanol-aqueous (1:1) as well as aqueous fractions of Ziziphus spina christi leaves was evaluated through MTT assay against MCF-7 cell line. Cell cycle inhibition and apoptosis induction were assessed by flowcytometry cycle RNase/PI analysis and Annexin V-FLUOS, respectively. Apoptosis was also analyzed by immunoblotting assay. Results: Our results indicated that the ethanolic fraction had the lowest $IC_{50}$ value (0.02 mg/ml), induced cell cycle arrest at the G1/S phase as well as apoptosis after a 48h of treatment. Conclusions: This is the first report on anticancer effect of Ziziphus spina christi ethanolic fraction on breast cancer cells, providing a scientific basis for its utility in traditional medicine. However, further in-depth studies are needed to confirm the precise mechanisms.

• Progress in Superconductivity
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• v.10 no.1
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• pp.60-67
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• 2008

We present domestic efforts for superconducting fault current limiter (SFCL) application in the Korea Electric Power Corporation (KEPCO) grid and pending points at issue. KEPCO's decision to upgrade the 154 kV/22.9 kV main transformer from 60 MVA to 100 MVA cast a problem of high fault current in the 22.9 kV distribution lines. The grid planners supported adopting an SFCL to control the fault current. This environment friendly to SFCL application must be highly dependent upon the successful development of SFCL having specifications that domestic utility required. The required conditions are (1) small size of not greater than twice of 22.9 kV gas insulated switch-gear (GIS), (2) sustainability of current limitation without the line breaking by circuit breakers (CB) for maximum 1.5 seconds. Also, optionally, recommended is (3) the reclosing capability. Conventional resistive SFCLs do not meet (1) $\sim$ (3) all together. A hybrid SFCL is an excellent solution to meet the conditions. The hybrid SFCL consists of HTS SFCL components for fault detection and line commutation, a fast switch (FS) to break the primary path, and a limiter. This characteristic structure not only enables excellent current limiting performances and the reclosing capability, but also allows drastic reduction of HTS volume and small size of the cryostat, resulting in economic feasibility and compactness of the equipment. External current limiter also enables long term limitation since it is far less sensitive to heat generation than HTS. Semi-active operation is another advantage of the hybrid structure. We will discuss more pending points at issues such as maintenance-free long term operation, small size to accommodate the in-house substation, passive and active control, back-up plans, diagnosis, and so on.