• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.152-163
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• 1995

This experiment was performed to observe the adhesion pattern and microleakage in the gingival margin according to variation in the resin cement thickness which results from thickness of Die spacer. which is considered to effect the adaptability of the composite resin inlays. Clearfil CR inlays were fabricated on stone models with CR Sep applicated once and Nice fit twice, 4 times, and 6 times each. After 2nd curing within the CRC-100 oven, CR inlays were cemented with CR inlay cement. Dye(2% methylene blue) penetration and adhesion pattern were evaluated after sectioning of gingival margin into :3 pieces. The results were as follows ; 1. The thickness of resin cement showed unevenchanging pattern with that of die spacer, namely, it was increased until 4 times' application of Nice-Fit but was decreased with 6 times' application of that. 2. The degree of dye penetration wasn't affected by cement thickness within a limited value. 3. Most of dye penetration was shown through the interface between cement and enamel rather than the interface between cement and CR inlay. This shows that the affinity of resin cement for CR inlay was superior to the adhesive strength with tooth structure. 4. No gap was found at the interface between enamel and cement but some showed separation between dentin and cement. It is concidered that the contraction force of cement was less than the bond strength with the enamel. 5. Lots of voids were found in the CR inlay and resin cement. There was a pooling tendency of bonding agent and cement in the axiogingival line angle portion. 6. In some specimens, cracks were shown in enamel margin. From this it could be considered that cavity preparation and surface treatment weakened the tooth structure.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.11
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• pp.575-580
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• 2001

In this paper, using $500\mum-thickness\; (100)\; silicon\; wafer,\; flat\; 65\mum-thickness$ silicon mirror plates were fabricated through dry etching and wet etching, and $45\mum-depth$ grooved driving electrodes were fabricated through UV-LIGA process. Four shapes of the driving electrode were fabricated: twenty four grooves of the $50\mum-width$, twelve grooves of the $100\mum-width$, six grooves of the $200\mum-width$, and no grooves on the driving electrode. Fabricated mirror plate size and spring size are $2400\times2400\times65\mum3\; and \;500\times10\times65\mum3,$ respectively. Mirror plate parts and driving electrodes were assembled into the scanning mirrors. Measured natural resonance frequencies were about 600Hz which have error within $\pm 2%$ to calculated value. Due to the squeeze effect in the narrow gap between the mirror plate and the driving electrode, measured resonance frequencies were reduced as raising the amplitude of the mirror plate. In a case of driving electrode without grooves, the resonance frequency was reduced largely, compared with a case of driving electrode with grooves. According to the experimental results, squeeze effect was smaller in the driving electrode with smaller-width and many grooves. Therefore, the driving electrode with smaller-width and many grooves was effective in low voltage and high speed operation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.158-166
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• 1999

The purpose of this study was to investigate the correlation between airborne total dust and man-made mineral fibers (MMMF), and to estimate total dust concentration to maintain below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV$^{(R)}$) for the MMMF. The regression coefficients between airborne total dust concentrations and fiber concentrations determined in the industries producing glass fibers, rock wool. refractory ceramic and continuous filament glass fibers products were 0.41, 0.42, 0.20 and 0.19, respectively. The size characteristics of fibers as well as the amounts of contaminated non-fibrous dusts could affect the correlation intensities. When total dust and fiber exposure data were compared with the occupational exposure limits, there was a large gap between two evaluation results. The regression coefficient between total dust and fiber data was increased ($r^2=0.88$) in the process of insulation installation generating in the higher levels of glass or rock wool fibers. In this case, an estimated total dust concentration of glass wool or rock wool fibers complying with the ACGIH TLV (1 f/cc) was $1.7mg/m^3$. In conclusion, the total dust and fibers concentrations was highly correlated at the higher exposure levels so that total dust-monitoring data could be used to control simply and economically and to estimate worker's exposure to fibers.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.25-31
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• 2005

With the recent surge of public interests in real estate markets, public demand on cadastral information including cadastral maps has been increasing rapidly. However, the torrent system that provides cadastral information falls far short of meeting public demand due to its main focus on government users. In order to reduce the gap between public demand and supply of cadastral information, a new business model is needed that fulfills public needs and at the same time generates profits for service providers. The main objective of this paper is to identify a potential business model that satisfies the above conditions. To achieve this objective, we have explored the unmet needs of public users in real estate transactions and examined whether the unmet needs can best be served by the resources and capabilities of Korea Cadastral Survey Corporation. Then, we have crafted a detail business model i.e., Syndication model, that includes value propositions, resource maps, and revenue and cost estimations. Finally, a plan is proposed to serve government users better with the financial surplus from the proposed business model. The results of this study can be useful for other similar areas including GIS, ITS and telematics, academically as well as practically.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.137-143
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• 2016

This study was conducted to investigate the electrolyte metabolic responses to a 100 km ultra-marathon in 22 male amateur runners. Their average age was $50.91{\pm}4.77$ years old and their $VO_2max$ value was $48.19{\pm}6.4 mL/kg/min$. The participants completed the race with a mean finishing time of $205.55{\pm}19.61$ minute. Electrolyte parameters based on blood tests including calcium, inorganic phosphorus, magnesium, sodium, potassium, chloride, total carbon dioxide, anion gap, plasma volume change and osmolality were measured pre-race, at 50 km, and at 100 km (post-race). Only slight changes in sodium level with no cases of hypernatremia or hyponatremia were observed. Additionally, all the electrolyte parameters changes were within the normal range and plasma volumes were unchanged. Overall, amateur marathon runners are not at risk to develop clinically significant electrolyte or osmolality changes during a 100 km ultra-marathon.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.228-236
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• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from rice fields. This method has the advantages of being simple, easily available and economical. However, a measurement result using the chamber method is an estimated value and is complete when the uncertainty is estimated. The methane emissions from a rice paddy account for the largest portion of the greenhouse gas emissions in the agriculture sectors. Although assessment of uncertainty components affecting methane emission from a rice paddy is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. The goal of this study was to elucidate influencing factors on measurement uncertainty of methane concentrations measured by a closed automated chamber system from a rice paddy. METHODS AND RESULTS: The methane sampling system is located in the rice paddy in Gyeonggi-do Agricultural Research and Extension Services (37°13'15"N, 127°02'22"E). The primary measurement uncertainty components influencing methane concentrations (influencing factors) investigated in this research were repeatability, reproducibility and calibration in the aspects of methane sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor were quantified and compared. CONCLUSION: Results of this study showed what influencing factors were more important in determination of methane concentrations measured using the chamber system and analytical instrumentation located in the monitoring site. Quantifying the measurement uncertainty of the methane concentrations in this study would contribute to improving measurement quality of methane fluxes.

• Journal of Technology Innovation
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• v.21 no.2
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• pp.255-283
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• 2013

Despite its theoretically and practically important value, the concept of technological innovation orientation has not been theoretically well established and thus has not been operationalized appropriately in previous studies. Given such a gap in prior research regarding technological innovation orientation, this study proposed a refined conceptualization of technological innovation orientation and a new measurement instrument for capturing the refined concept of technological innovation orientation. More specifically, this study conceptualized technological innovation orientation as having two components of proclivity to technological leadership and openness to technological innovation and developed a measurement instrument for operationalizing the two-dimensional concept of technological innovation orientation. Based on the proposed conceptualization and operationalization of technological innovation orientation, this study also investigated the relationship between technological innovation orientation and firm performance. Based on a sample of 97 Korean IT SMEs, the results demonstrated a high reliability and validity for the measurement instrument developed to operationalize the two-dimensional technological innovation orientation. The results further revealed that technological innovation orientation is positively related to technological innovation performance and that technological innovation performance positively mediates the relationship between technological innovation orientation and financial performance.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.174-185
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• 2005

This paper presents the design, fabrication, and testing results of a dual stage actuator system for a fine positioning of magnetic heads in magnetic disk drives. A novel rotary microactuator which is electrostatically driven and utilized as a secondary actuator was designed. The stator and rotor electrodes in the microactuator was revised to have the optimal shapes and hence produces much higher rotational torque compared with the conventional comb-shape electrodes. The microactuators were successfully fabricated using SoG(silicon on glass) processing technology, which is known as being cost-effective. The fabricated microactuator has the structural thickness of $45{\mu}m$ with the gap width of approximately $3{\mu}m$. The dynamic characteristic of microactuator/slider assembly was investigated, and its natural frequency and DC gain were measured to be 3.4kHz and 32nm/V, respectively. The microactuator/slider assembly was integrated into a HDD model V10 of Samsung Electronics Co. and a dual servo algorithm was tested to explore the tracking performance of dual stage actuator system where the LDV signals instead of magnetic head signals were used. Experimental results indicate that this system achieves the tracking accuracy of 30nm. This value corresponds to a track density of 85,000 track per inch(TPI), which is about 3 times greater than that of current hard disk drives.

• Journal of Korean society of Dental Hygiene
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• v.9 no.2
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• pp.1-11
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• 2009

The purpose of this study was to examine the state of career and employment among dental hygiene students in an attempt to get an accurate grip on their preparation for career and employment. And it's also meant to help improve the efficiency of guidance by dental hygiene education institutions for career and employment. The subjects in this study were every dental hygiene student at three different colleges. After a self-administered survey was conducted, the following findings were given: 1. In regard to the future prospects of dental hygienist, 44.2 percent of the students investigated believed that there would be a bright future for dental hygienist, and 55.8 percent didn't agree to that or considered the prospects to be neither bright nor bleak. 2. As to the motivation of choosing the department of dental hygiene, 51.2 percent thought that it was easy for dental hygienists to get a job, and 22.2 percent wanted to be a professional. 3. Concerning preference for workplace, they hoped to work in a hospital-sized or larger institutions including dental hospitals. As to the reason why they wanted a job, 76.2 percent had their sight set on standing on their own feet. 4. As for the top priority for employment, they took interpersonal relationship into account the most(3.63), followed by aptitude(3.52) and working conditions/environments(3.51). 5. In terms of job values by academic year, all the freshmen, sophomores and juniors attached the most importance to interpersonal relationship. By academic standing in the previous semester, the students who got an A, B or C put more value on human relations, and those who got a D gave more weight to social status and fame. The gap between them was statistically significant. As for the impact of the high schools they graduated from, they took the most statistically significant consideration on interpersonal relationship irrespective of their alma mater.

• Journal of Information Technology Services
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• v.16 no.3
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• pp.17-45
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• 2017

Health Information Exchange (HIE) is expected to improve the quality and efficiency of care by allowing providers online access to healthcare information generated by other providers at the point of care. However, the adoption of the technology in Korea has been slow since its pilot program in 2007~2010 at Seoul National University Bundang Hospital. The objective of this study was to survey stakeholders on the incentive program for the facilitation of HIE adoption. We surveyed 39 experts representing 6 categories of stakeholders-provider, insurer, government, information service firms, customers, and medical informatics experts for the interviews. Interview questions included program objectives, program participation requirements, incentive payment method, and administrative burden for program participation. Experts indicated that the quality of care was the most important value the program should aim to achieve through the HIE adoption. They suggested that the requirements and administrative burden for participation should be kept at minimum to recruit a large number of providers to the program, which is an indicator of program success. Experts were divided on the payment method whether the incentive should be paid as a part of the fee payment scheme operated by the National Health Insurance (NHI) or should be a payment made independent of the NHI. The source of the divide was conflict of interest among stakeholders as to who pays for the program, and the insurer and consumer groups were against the NHI taking the financial burden. It appeared to be the most significant factor for the successful program launching to resolve the gap in perceptions about benefits of the technology among stakeholders and to win the willingness to pay for the program.