• International Area Studies Review
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• v.21 no.4
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• pp.195-222
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• 2017

This exploratory study analyses the factors, sources and effects of the regional competitive advantage of Jeju Island in Korea in global competition era. The competitive advantage of Jeju Province is analysed with the triple diamond model based on Porter's model for the competitive advantage of nations. The competitive advantage factors of Jeju Province are measured through the competitive advantage of the hospitality industry, which is one of the major industries of Jeju Island. These factors include outstanding natural landscape, domestic hospitality industry workforce, social overhead capital, massive domestic and international tourists, growth of related industries such as duty free shops and casinos, and coincidences such as Jeju Olle trail construction and Chinese government's international travel approval. Since these factors are based on local, domestic and international management resources, this study suggests that obtaining such resources is critical among Jeju hospitality industry in gaining the competitive advantage. Although the competitive advantage of Jeju hospitality industry is increasing, the organic connections with the regional economy are required for improvements on Jeju residents' quality of life. This study examines the factors and origins of competitive advantages on a regional level instead of a national level, and further investigates how the characters and origins of these factors affect the local economy. The results suggest that the triple diamond model is suitable for evaluating the regional competitive advantages.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.203-208
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• 2022

Recently, various digital technology issues such as e-Navigation, Maritime Autonomous Surface Ship (MASS) and Smart ships have constantly emerged in the maritime industry, based on the fourth industrial revolution. The International Maritime Organization is gradually tightening regulations for marine safety and marine environmental protection, and these strengthened regulations are leading to new maritime industries. Thus, the purpose of this study was to design a suitable model to analyze the industrial competitiveness of domestic autonomous operation technology industry, based on the Porter's diamond model. Based on a total of five evaluation factors and 13 detailed factors, the industrial competitiveness of the domestic autonomous operation technology industry was evaluated qualitatively and quantitatively. This industry, which is in the early stage of industrial development, was evaluated as 16.9 points relative to indexing industrial competitiveness. Currently, it is characterized by the simultaneous development of related regulations and core technologies, from the establishment of the scope of the industry. The industrial competitiveness evaluation considering these industrial characteristics is expected to serve as the basis for strategic support and new industrial policy, and impact a wide range of related industries such as shipping, logistics, ports, and shipbuilding and equipment industries.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.54-54
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• 2018

To optimize the deposition parameters of diamond films, the temperature, pressure, and distance between the filament and the susceptor need to be considered. However, it is difficult to precisely measure and predict the filament and susceptor temperature in relation to the applied power in the hot filament chemical vapor deposition (HFCVD) system. In this study the temperature distribution inside the system was numerically calculated for the applied powers of 12, 14, 16 and 18 kW. The applied power needed to achieve the appropriate temperature at a constant pressure and other conditions was deduced, and applied to actual experimental depositions. The numerical simulation was conducted using the commercial computational fluent dynamics software, ANSYS-FLUENT. To account for radiative heat-transfer in the HFCVD reactor, the discrete ordinate (DO) model was used. The temperatures of the filament surface and the susceptor at different power levels were predicted to be 2512 ~ 2802 K, and 1076 ~ 1198 K, respectively. Based on the numerical calculations, experiments were performed. The simulated temperatures for the filament surface were in good agreement with experimental temperatures measured using a 2-color pyrometer. The results showed that the highest deposition rate and the lowest deposition of non-diamond was obtained at a power of 16 kW.

• Restorative Dentistry and Endodontics
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• v.49 no.3
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• pp.30.1-30.12
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• 2024

Objectives: The aim of the current study was to evaluate the effect of polishing systems and surface sealant on the color stability and whiteness index of single-shade resin composites after staining and bleaching. Materials and Methods: Three single-shade (Omnichroma, Charisma Diamond One, Zenchroma) and one multi-shade (Filtek Z250) materials were tested. From each resin composite, 40 specimens were prepared. The specimens were divided into 4 subgroups (n = 10) according to the surface treatments: 1-step polishing, 1-step + Biscover LV, 2-step polishing, and 2-step polishing + Biscover LV. Color differences (ΔE₀₀) were calculated after being immersed in the coffee solution for 12 days. After the staining, the specimens were immersed in a whitening mouthrinse (Crest-3D White) for 12 hours. Whiteness index differences (ΔWI_D = WI_D after staining - WI_D after bleaching) values were recorded. The generalized linear model was used for analysis (p< 0.05). Results: The lowest and highest ΔE₀₀ values were found for Zenchroma and Charisma Diamond One respectively. Sealed groups indicated higher ΔE₀₀ values than nonsealed groups with significant differences (p = 0.008). The lowest and highest ΔWI_D values were found for Zenchroma and Charisma Diamond One respectively. Sealed groups indicated lower ΔWI_D values than nonsealed groups with significant differences (p = 0.022). Conclusions: The use of surface sealant increased the discoloration and showed less whiteness change in resin materials. When the 1-step was compared with the 2-step polishing, the effects on the color stability and whiteness index values of the resin materials were similar.

• Journal of Service Research and Studies
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• v.8 no.4
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• pp.53-75
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• 2018

Bicycle-sharing as a product service system in the sharing economy, its characteristic is that users can go to nearby places by the public bike at any time however they don't need to have their own bicycle. However, the service quality of bicycle-sharing and satisfaction of users continuously decrease with the rapid growth number of bicycle-sharing users in China. Based on the double diamond model and from the perspective of service design, this research studies the service experience of bicycle-sharing of Chinese users, focuses on the potential pain points of Chinese users when using the public bike, and designs the optimum proposal to promote users' satisfaction. According to the research result, the research builds a new concept which can satisfy users' demand for communication, enjoyment and option during the cycling. The experience of new service system of bicycle-sharing makes humanized and subconscious interaction possible.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.987-992
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• 1997

Burrs always come out with the machining of ducterial with small size. Though the size of burrs is small, burrs dominate deterioration of the accuracy of the micro grooves. So the burr generation model especially side burr generation model was investigated to predict the size of the burrs at the given cutting conditions. The side shear plane is introduced to build the burr generation model and the width of side shear plane nomalized with cutting depth is defined with the shear angle. From the theoretical observation, the width of side shear plane can vary up 40% of the cutting depth. To determine the size of burr and stiffness, single groovings were carried out and it was found that there exist a critical depth of cut that the size or stiffness of the burr vary.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.83-87
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• 2001

A 110 mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machinable, but not polishable due to its ductility. A harder material, Ni, is usually electrolessly coated on an Al substrate to increase the surface hardness for optical polishing. Aspheric metal secondary mirror without a conventional polishing process, the surface roughness of Ra=10nm, and the form error of $Ra={\lambda}/12({\lambda}=632nm)$ has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of electroless-Ni coated Al alloy and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.7
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• pp.1003-1012
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• 2008

A three dimensional numerical study has been applied to predict the turbulent fluid flow and heat transfer characteristics for the rectangular channel with different types of baffles. Four different types of the baffles are used. The inclined baffles have the width of 19.8 cm, the square diamond type hole having one side length of 2.55 cm, and the inclination angle of $5^{\circ}$. Reynolds number is varied between 23,000 and 57,000. The SST k-${\omega}$ turbulence model is used in the present numerical study. The validity of the numerical results is examined with the experimental data. The numerical results of the flow field depict that the flow patterns around the different baffle type are entirely different and it significantly affects the local heat transfer characteristics. The heat transfer and friction factor depend significantly on the number of baffle holes. It is found that the heat transfer enhancement of baffle type II (3 hole baffle) has the best values.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.403-408
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• 2021

Various surface colors are predicted and implemented using the interference color generated by controlling the thickness of nano-level diamond like carbon (DLC) thin film. Samples having thicknesses of up to 385 nm and various interference colors are prepared using a single crystal silicon (100) substrate with changing processing times at low temperature by plasma-enhanced chemical vapor deposition. The thickness, surface roughness, color, phases, and anti-scratch performance under each condition are analyzed using a scanning electron microscope, colorimeter, micro-Raman device, and scratch tester. Coating with the same uniformity as the surface roughness of the substrate is possible over the entire experimental thickness range, and more than five different colors are implemented at this time. The color matched with the color predicted by the model, assuming only the reflection mode of the thin film. All the DLC thin films show constant D/G peak fraction without significant change, and have anti-scratch values of about 19 N. The results indicate the possibility that nano-level DLC thin films with various interference colors can be applied to exterior materials of actual mobile devices.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.623-628
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• 2002

A meshfree formulation for the calculation of energy band structure is presented. The conventional meshfree shape function is modified to handle the periodicity of Bravais lattice, and applied to the calculation of real-space electronic-band structure. Numerical examples include the Kronig-Penney model potential and the empirical pseudopotentials of diamond and zinc-blonde semiconductors. Results demonstrate that the meshfree method be a promising one as a real-space technique for the calculations of diverse physical band structures.