• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.317-317
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• 2018

Baseflow which is one of the unmeasurable components of streamflow and slowly flows through underground is important for water resource management. Despite various separation methods from researches preceded, it is difficult to find a significant separation method for baseflow separation. This study applied the MRC method and developed the improved approach to separate baseflow from total streamflow hydrograph. Previous researchers utilized the whole streamflow data of study period at once to derive synthetic MRCs causing unreliable results. This study has been proceeded with total nine areas with gauging stations. Each three areas are selected from 3 domestic major watersheds. Tool for drawing MRC had been used to draw MRCs of each area. First, synthetic MRC for whole period and two other MRCs were drawn following two different criteria. Two criteria were set by different conditions, one is flow condition and the other is seasonality. The whole streamflow was classified according to seasonality and flow conditions, and MRCs had been drawn with a specialized program. The MRCs for flow conditions had low R2 and similar trend to recession segments. On the other hand, the seasonal MRCs were eligible for the baseflow separation that properly reflects the seasonal variability of baseflow. Comparing two methods of assuming MRC for baseflow separation, seasonal MRC was more effective for relieving overestimating tendency of synthetic MRC. Flow condition MRCs had large distribution of the flow and this means accurate MRC could not be found. Baseflow separation using seasonal MRC is showing more reliability than the other one however, if certain technique added up to the flow condition MRC method to stabilize distribution of the streamflow, the flow conditions method could secure reliability as much as seasonal MRC method.

• Journal of Periodontal and Implant Science
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• v.52 no.2
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• pp.91-115
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• 2022

Purpose: This systematic review aimed to compare the efficacy, defined in terms of the mean percentage of root coverage (mRC), of surgical treatment approaches combined with adhesive restorations of non-carious cervical lesions (NCCLs) to that of root coverage alone in patients with a single gingival recession (GR) and NCCL. Methods: A literature search was conducted to identify longitudinal studies reporting the mRC following treatment for the correction of GR defects associated with NCCLs using a combination of surgical and restorative techniques in systemically and periodontally healthy patients. Results: The search resulted in the retrieval of 12,409 records. Seven publications met the inclusion criteria for the qualitative synthesis of data. The mRCs ranged from 69% to 97%. In the medium term, the gingival margin position was more stable when a connective tissue graft (CTG) was used, independently of whether restoration of teeth with NCCLs was performed. Conclusions: The strength of the evidence was limited by methodological heterogeneity in terms of study design as well as the unit and period of analysis, which precluded a metaanalysis. Although no definitive conclusion could be drawn due to the lack of sufficient evidence to estimate the effectiveness of the interventions, CTG-based procedures contributed to gingival margin stability regardless of the performance of restoration to treat NCCLs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.142-149
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• 2022

This study attempts to analyze the economic impact of the service robot industry using Input-Output analysis, which is conducted based on Demand-driven model, the Leontief price model, the Backward and Forward Linkage Effects, and the Exogenous Methods. In a Demand-driven model analysis, we can conclude that the service robot industry contains characteristics of both the manufacturing industry and the service industry, which causes a positive impact on the overall industry by compensating for the weaknesses of the two industries. The Leontief price analysis indicates when wages in the service robot industry increase, prices related to robot manufacturing also increase. Also, when profits in the service robot industry increase, prices related to service provision increase, too. The Backward and Forward Linkage Effects analysis shows that the service robot industry is highly sensitive to the current economic condition and has a great influence on the service industry. The service robot industry can highlight the aspect of service characteristics when the manufacturing industry is in recession and vice versa. In addition, the service robot industry can be regarded as a value-adding and domestic economy promoting industry which utilizes knowledge of information and communication technologies. It is important to foster the service robot industry in South Korea, which is in economic recession to provide an opportunity to stimulate the growth of both service and robot industries.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.111-118
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• 2009

Purpose: The integrity of interproximal hard/soft tissue has been widely accepted as the key determinant for success or degree of root coverage following the connective tissue graft. However, we reason that the gingival biotype of an individual, defined as the distance from the interproximal papilla to gingiva margin, may be the key determinant that influence the extent of root coverage regardless of traditional classification of gingival recession. Hence, the present study was performed with an aim to verify that individual gingival scalloping pattern inherent from biotype influence the level of gingival margin following the connective tissue graft for root coverage. Methods: Test group consisted of 43 single-rooted teeth from 21 patients (5 male and 16 female patients, mean age: 36.6 years) with varying degrees of gingival recession requiring connective tissue graft; 20 teeth of Miller class I and 23 teeth of Miller class III gingival recession, respectively. The control group consisted of contralateral teeth which did not demonstrate apparent gingival recession, and thus not requiring root coverage. For a biotype determination, an imaginary line connecting two adjacent papillae of a test tooth was drawn. The distance from this line to gingival margin at mid-buccal point and this distance (P-M distance) was designated as "gingival biotype" for a given individual. The distance was measured at baseline and 3 to 6 months examinations postoperatively both in test and control groups. The differences in the distance between Miller class I and III were subject to statistical analysis by using Student.s t-test while those between the test and control groups within a given patient were by using paired t-test. Results: The P-M distance at 3 to 6 months postoperatively was not significantly different between Miller class I and Miller class III. It was not significantly different between the test and control group in a given patient, either, both in Miller class I and III. Conclusions: The amount of root coverage following the connective tissue graft was not dependent on Miller's classification, but rather was dependent on P-M distance, strongly implying that the gingival biotype of a given patient may play a critical impact on the level of gingival margin following connective tissue graft.

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.179-187
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• 2000

The objectives of this study were to measure keratinized gingival thickness in healthy Korean adults, and to correlate the keratinized gingival thickness with width of keratinized gingiva, probing pocket depth and gingival recession.Thickness measurements were performed in 37 Korean dental students using an ultrasonic device(SDM). Width of keratinized gingiva, gingival recession and probing pocket depth were measured with a Williams periodontal probe.The results showed that the keratinized gingival thickness varied from 0.83 mm(canines) to 1.16 mm(central incisors) in the maxilla and, in the mandible, from 0.68 mm(1st premolars) to 1.69 mm(2nd molars). In a stepwise multiple linear regression analysis, 23% of variation of gingival thickness could be explained by width of keratinized gingiva and probing pocket depth. It could be concluded that the keratinized gingival thickness depends on tooth type and correlates with width of keratinized gingiva and probing pocket depth.

• Journal of Korea Technology Innovation Society
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• v.18 no.2
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• pp.264-291
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• 2015

This research is to empirically analyze the effects of governmental policy including R&D subsidiary and tax reduction, which are both direct and indirect financial supports, during the examination period (2007~2009). The analysis was based on 2,751 firms that received governmental support via both R&D subsidiary and tax reduction with 7,038 panel events during the economic recession (2008~2009) and found that governmental support drives R&D investment of firms during the recession. The contribution of this research is that investigation of policy effectiveness categorized by firm sizes, particularly during the economic crisis. The result of the study is that during the recession, large firms had more elasticity increase towards tax reduction whereas smaller firms and ventures had it towards direct financial subsidiary. The elasticity increase of both large and small firms was in positive association with firms' R&D investment. The result indicates that government support obviously has positive influence on R&D investment of firms during the crisis, even enforcing the investment.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.151-152
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• 2020

최근 코로나바이러스(COVID-19)의 여파로 경기침체가 이루어 지고 있는 중, 반대로 역성장을 이루고 있는 중고시장의 흥행요인을 분석하고, 또한 기존 지역단위의 중고거래시장이 아닌 새로운 소규모 동네단위 중고시장의 급성장 요인을 분석하여 향후동향을 예측하고자 한다.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.265-274
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• 2013

The business cycle during a recession leads to negative effects on raising funds and operations management of company. In particular, the company with many inventories in the recession causes liquidity problem. Which leads to frustration in the competitive strategy management. In this case the company experiencing cash or liquidity problems attempts to reduce its investment in inventory. However, reducing inventory investment makes problems to increase inventory operating costs. This paper presents sensitivity of total cost compared to the size for reducing inventory investment. This will guarantee the relevance of the reducing inventory investment. Optimal Inventory levels also may be required to be less than the optimal levels without reduction on inventory investments.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.81-93
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• 1999

Non-surgical therapy is still an important technique in periodontal treatment. In this study, scaling and root planing(SRP) with or without concomitant subgingival curettage were compared clinically and microbiologically. 14 moderate adult periodontitis patients were included in this study. After 2 weeks from screening visit, with split mouth design, one quadrant was treated by SRP, and the opposite side was treated by SRP with subgingival curettage. Clinical measurement and microbiological analysis was taken at baseline, 1 month, 3 month post-treatment. Clinical parameters used in this study was probing depth, gingival recession, gingival index, bleeding on probing, plaque index, tooth mobility(Periotest Value). Microbiological analysis consisted of determination of the percentages of 4 bacterial groups according to morphologic type with phase-contrast microscope and measuring Black-pigmented Bacteroides after anaerobic culture. 1. There were significant changes in probing depth and gingival recession at 1 month(P<0.05), and these changes remained through 3 month. However, no significant differences were observed between two groups(P<0.05). 2. There were also significant reductions in gingival index and bleeding on probing at 1 month(P<0.05),and these reduced levels were maintained through 3 month with no significant differences between two groups(P<0.05). 3. In both groups, motile bacteria decreased significantly at 1 months(P<0.05), but increased nearly to baseline level at 3 month. 4. The percentages of Black-pigmented Bacteroides, in both groups, decreased significantly at 1 month(P<0.05), and in the subgingival curettage group, significant more reductions were observed than in the root planing group(P<0.05). At 3 month, significant reduction was found in subgingival curettage group only(P<0.05). According to these results, we surmised that concomitant subgingival curettage and root planing give some advantageous effect on bacterial recolonization.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.183-192
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• 1993

The purpose of this epidermiological analysis was to evaluate the periodontal status of Korean young adults(twenties) in order to provide detail & baseline data for frequence of periodontal disease. Two hundred and fifty young adults, aged 20-29 years, were selected by random sampling. Dental visity, scaling treatment, education, income, toothbrushing frequence & method were checked, and plaque index(Loe and silness), calculus index(Ramfjord), gingival index(Loe and silness), attached gingival width, perio probing depth, gingival recession were measured. The obtained results were as follows. 1. Average plaque index(1.96), calculus index(1.43), gingival index(1.7) were higher in mandible than maxillar. It was most prevalent in lst molar. 2. Average attached gingival width(4.0mm) was wider in maxillar than mandible. It was most prominent in lateral incisor. 3. Pocket depth(>4mm) was distributed in 42% subject, it was higher in mandible than maxilla and most prevalent in 1st molar. 4. Gingival recession(>1mm) was distributed in 94% subject, it was higher in mandible than maxilla, and most prevalant in canine. 5. According to unpaired t-test, palque index, calculus index, gingival index were not statistically significant in history of scaling treatment, level of eduction and account of income, but were showed statistically significant in histrory of dental clinic.(PB0.05) 6. According to ANOVA test, correlation between tooth-brushing(frequence, method) and gingival index was showed statistically significant.(P<0.05) 7. There was gingival recessionof 87% subject in only one time brushing, 80% subject in two time, and 68% subject in three times. There was gingival recessionof 68% subject in leftright direction tooth brushing, 73% subject in upper-low method and 77% subject in combination method.