• The Journal of Korean Academy of Prosthodontics
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• v.47 no.3
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• pp.301-311
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• 2009

Statement of problem: Flapless implant surgery using a soft tissue punch device requires a circumferential excision of the mucosa at the implant site. To date, Although there have been several reports on clinical outcomes of flapless implant surgeries, there are no published reports that address the appropriate size of the soft tissue punch for peri-implant tissue healing. Purpose: In an attempt to help produce guidelines for the use of soft tissue punches, this animal study was undertaken to examine the effect of soft tissue punch size on the healing of peri-implant tissue in a canine mandible model. Material and methods: Bilateral, edentulated, flat alveolar ridges were created in the mandibles of six mongrel dogs. After a three month healing period, three fixtures (diameter, 4.0 mm) were placed on each side of the mandible using 3 mm, 4 mm, or 5 mm soft tissue punches. During subsequent healing periods, the peri-implant mucosa was evaluated using clinical, radiological, and histometric parameters, which included Gingival Index, bleeding on probing, probing pocket depth, marginal bone loss, and vertical dimension measurements of the peri-implant tissues. Results: The results showed significant differences (P <0.05) between the 3 mm, 4 mm and 5 mm tissue punch groups for the length of the junctional epithelium, probing depth, and marginal bone loss during healing periods after implant placement. When the mucosa was punched with a 3 mm tissue punch, the length of the junctional epithelium was shorter, the probing depth was shallower, and less crestal bone loss occurred than when using a tissue punch with a diameter $\geq$ 4 mm. Conclusion: Within the limit of this study, the size of the soft tissue punch plays an important role in achieving optimal healing. Our findings support the use of tissue punch that 1 mm smaller than implant itself to obtain better peri-implant tissue healing around flapless implants.

• Journal of Korea Port Economic Association
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• v.37 no.2
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• pp.73-89
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• 2021

The handysize bulk carriers are capable of transporting a variety of cargo that cannot be transported by mid-large size ship, and the spot chartering market is active, and it is a market that is independent of mid-large size market, and is more risky due to market conditions and charterage variability. In this study, Granger causality test, the Impulse Response Function(IRF) and Forecast Error Variance Decomposition(FEVD) were performed using monthly time series data. As a result of Granger causality test, coal price for coke making, Japan steel plate commodity price, hot rolled steel sheet price, fleet volume and bunker price have causality to Baltic Handysize Index(BHSI) and charterage. After confirming the appropriate lag and stability of the Vector Autoregressive model(VAR), IRF and FEVD were analyzed. As a result of IRF, the three variables of coal price for coke making, hot rolled steel sheet price and bunker price were found to have significant at both upper and lower limit of the confidence interval. Among them, the impulse of hot rolled steel sheet price was found to have the most significant effect. As a result of FEVD, the explanatory power that affects BHSI and charterage is the same in the order of hot rolled steel sheet price, coal price for coke making, bunker price, Japan steel plate price, and fleet volume. It was found that it gradually increased, affecting BHSI by 30% and charterage by 26%. In order to differentiate from previous studies and to find out the effect of short term lag, analysis was performed using monthly price data of major cargoes for Handysize bulk carriers, and meaningful results were derived that can predict monthly market conditions. This study can be helpful in predicting the short term market conditions for shipping companies that operate Handysize bulk carriers and concerned parties in the handysize chartering market.

• Journal of the Korean earth science society
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• v.45 no.2
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• pp.157-171
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• 2024

The purposes of this study were: (1) to revalidate the revised Systems Thinking Measuring Instrument (Re_STMI) reported by Lee et al. (2024) among Vietnamese high school students and (2) to investigate the differences in systems thinking abilities between Korean and Vietnamese high school students. To achieve this, data from 234 Vietnamese high school students who responded to translated Re_STMI consisting of 20 items and an Scale consisting of 20 items were used. Validity analysis was conducted through item response analysis (Item Reliability, Item Map, Infit and Outfit MNSQ, DIF between male and female) and exploratory factor analysis (principal axis factor analysis using Promax). Furthermore, structural equation modeling was employed with data from 475 Korean high school students to verify the latent mean analysis. The results were as follows: First, in the item response analysis of the 20 translated Re_STMI items in Vietnamese, the Item Reliability was .97, and the Infit MNSQ ranged from .67 to 1.38. The results from the Item Map and DIF analysis align with previous findings. In the exploratory factor analysis, all items were loaded onto intended sub-factors, with sub-factor reliabilities ranging from .662 to .833 and total reliability at .876. Confirmatory factor analysis for latent mean analysis between Korean and Vietnamese students yielded acceptable model fit indices (χ²/df: 2.830, CFI: .931, TLI: .918, SRMR: .043, RMSEA: .051). Lastly, the latent mean analysis between Korean and Vietnamese students revealed a small effect size in systems analysis, mental models, team learning, and shared vision factors, whereas a medium effect size was observed in personal mastery factors, with Vietnamese high school students showing significantly higher results in systems thinking. This study confirmed the reliability and validity of the Re_STMI items. Furthermore, international comparative studies on systems thinking using Re_STMI translated into Vietnamese, English, and other languages are warranted in the context of students' systems thinking analysis.

• Asia pacific journal of information systems
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• v.24 no.4
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• pp.443-472
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• 2014

To survive in the global competitive environment, enterprise should be able to solve various problems and find the optimal solution effectively. The big-data is being perceived as a tool for solving enterprise problems effectively and improve competitiveness with its' various problem solving and advanced predictive capabilities. Due to its remarkable performance, the implementation of big data systems has been increased through many enterprises around the world. Currently the big-data is called the 'crude oil' of the 21st century and is expected to provide competitive superiority. The reason why the big data is in the limelight is because while the conventional IT technology has been falling behind much in its possibility level, the big data has gone beyond the technological possibility and has the advantage of being utilized to create new values such as business optimization and new business creation through analysis of big data. Since the big data has been introduced too hastily without considering the strategic value deduction and achievement obtained through the big data, however, there are difficulties in the strategic value deduction and data utilization that can be gained through big data. According to the survey result of 1,800 IT professionals from 18 countries world wide, the percentage of the corporation where the big data is being utilized well was only 28%, and many of them responded that they are having difficulties in strategic value deduction and operation through big data. The strategic value should be deducted and environment phases like corporate internal and external related regulations and systems should be considered in order to introduce big data, but these factors were not well being reflected. The cause of the failure turned out to be that the big data was introduced by way of the IT trend and surrounding environment, but it was introduced hastily in the situation where the introduction condition was not well arranged. The strategic value which can be obtained through big data should be clearly comprehended and systematic environment analysis is very important about applicability in order to introduce successful big data, but since the corporations are considering only partial achievements and technological phases that can be obtained through big data, the successful introduction is not being made. Previous study shows that most of big data researches are focused on big data concept, cases, and practical suggestions without empirical study. The purpose of this study is provide the theoretically and practically useful implementation framework and strategies of big data systems with conducting comprehensive literature review, finding influencing factors for successful big data systems implementation, and analysing empirical models. To do this, the elements which can affect the introduction intention of big data were deducted by reviewing the information system's successful factors, strategic value perception factors, considering factors for the information system introduction environment and big data related literature in order to comprehend the effect factors when the corporations introduce big data and structured questionnaire was developed. After that, the questionnaire and the statistical analysis were performed with the people in charge of the big data inside the corporations as objects. According to the statistical analysis, it was shown that the strategic value perception factor and the inside-industry environmental factors affected positively the introduction intention of big data. The theoretical, practical and political implications deducted from the study result is as follows. The frist theoretical implication is that this study has proposed theoretically effect factors which affect the introduction intention of big data by reviewing the strategic value perception and environmental factors and big data related precedent studies and proposed the variables and measurement items which were analyzed empirically and verified. This study has meaning in that it has measured the influence of each variable on the introduction intention by verifying the relationship between the independent variables and the dependent variables through structural equation model. Second, this study has defined the independent variable(strategic value perception, environment), dependent variable(introduction intention) and regulatory variable(type of business and corporate size) about big data introduction intention and has arranged theoretical base in studying big data related field empirically afterwards by developing measurement items which has obtained credibility and validity. Third, by verifying the strategic value perception factors and the significance about environmental factors proposed in the conventional precedent studies, this study will be able to give aid to the afterwards empirical study about effect factors on big data introduction. The operational implications are as follows. First, this study has arranged the empirical study base about big data field by investigating the cause and effect relationship about the influence of the strategic value perception factor and environmental factor on the introduction intention and proposing the measurement items which has obtained the justice, credibility and validity etc. Second, this study has proposed the study result that the strategic value perception factor affects positively the big data introduction intention and it has meaning in that the importance of the strategic value perception has been presented. Third, the study has proposed that the corporation which introduces big data should consider the big data introduction through precise analysis about industry's internal environment. Fourth, this study has proposed the point that the size and type of business of the corresponding corporation should be considered in introducing the big data by presenting the difference of the effect factors of big data introduction depending on the size and type of business of the corporation. The political implications are as follows. First, variety of utilization of big data is needed. The strategic value that big data has can be accessed in various ways in the product, service field, productivity field, decision making field etc and can be utilized in all the business fields based on that, but the parts that main domestic corporations are considering are limited to some parts of the products and service fields. Accordingly, in introducing big data, reviewing the phase about utilization in detail and design the big data system in a form which can maximize the utilization rate will be necessary. Second, the study is proposing the burden of the cost of the system introduction, difficulty in utilization in the system and lack of credibility in the supply corporations etc in the big data introduction phase by corporations. Since the world IT corporations are predominating the big data market, the big data introduction of domestic corporations can not but to be dependent on the foreign corporations. When considering that fact, that our country does not have global IT corporations even though it is world powerful IT country, the big data can be thought to be the chance to rear world level corporations. Accordingly, the government shall need to rear star corporations through active political support. Third, the corporations' internal and external professional manpower for the big data introduction and operation lacks. Big data is a system where how valuable data can be deducted utilizing data is more important than the system construction itself. For this, talent who are equipped with academic knowledge and experience in various fields like IT, statistics, strategy and management etc and manpower training should be implemented through systematic education for these talents. This study has arranged theoretical base for empirical studies about big data related fields by comprehending the main variables which affect the big data introduction intention and verifying them and is expected to be able to propose useful guidelines for the corporations and policy developers who are considering big data implementationby analyzing empirically that theoretical base.

• KDI Journal of Economic Policy
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• v.13 no.4
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• pp.3-30
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• 1991

This paper examines Korea's exports of manufactures to the United States, Japan, and other OECD member countries in the 1974-89 period, focusing on the market share in the trade partners' imports. It decomposes the growth of exports into various effects, following the "constant-market-shares" analysis. For this purpose, the entire period is divided into three subperiods: 1974-78, 1978-83, and 1983-89. The paper also estimates a regression model of the market share determination, using the data of Korea's market share in U.S. imports. In the three subperiods under study, Korea's exports grew at different paces for varied reasons. The average annual growth rate was 28 %, 11 %, and 21 %, respectively. A large drop in the "competitiveness effect", that is, in the market-share growth rate, was mainly responsible for the decline in the export growth rate. The largest drop in the competitiveness effect was found in the light manufactures exports in the second period. The market share did not regain the rapid growth momentum. The main reason for the rise in export growth rate in the last subperiod was the "market-size effect"-a rise in the growth rate of the trade partners' imports. According to the regression results, high intensities in physical and human capital tended to lower the Korean manufacturing industries' market shares in the United States. This negative correlation was stronger in the case of human capital intensity, suggesting that Korea is relatively poorer in human capital endowment than in physical capital endowment when compared to the United States. This negative correlation between the market share and each of the two intensities became weaker overtime. This may be interpreted as the consequence of both physical and human capital accumulation which were faster than the labor force growth. Depreciation of the Japanese yen was estimated to have a negative influence on the Korean manufacturing industries' market share in the United States, and this negative influence became stronger each year in the 1980s. This seems to reflect the intensifying competition between the two countries' exports in U.S. import markets. The Heavy and Chemical Industry Policy of the 1970s, which promoted a number of selected industries by providing them with various incentives and inevitably discriminated against the rest of the industries, was estimated to have had strong negative effects on the export performance of the light manufacturing industries. This finding and the largest decline in the "competitiveness effect" -found in the light manufactures exports in the 1978-83 period-indicate that the Heavy and Chemical Industry Policy was mainly accountable for the drop in the export growth rate during the period. On the other hand, the rise in export growth rate during the subsequent subperiod was greatly impacted by the large scale exchange rate realignments of major currencies, especially by the appreciation of the Japanese yen, and other changes in international economic conditions.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.835-852
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• 2000

The ultimate goal of periodontal therapy is the regeneration of periodontal tissue and repair of function. For more than a decade there have been many efforts to develop materials and methods of treatment to promote periodontal wound healing. Recently many efforts are concentrated on the regeneration potential of material used in oriental medicine. In some in vitro and in vivo experiments, there have been many evidences that these materials have an effect on bone regeneration. The purpose of this study was to evaluate histologically and radiologically in Sprague-Dawley rats the effects of safflower seed extracts on the regeneration of the calvarial defects surgically produced. So in this study, the critical size defects were surgically produced in the calvarial bone of 30 Sprague-Dawley rats using the 8mm trephine bur. The safflower seed extract was applied into the defect of each rat in experimental group, whereas nothing was applied into the defect of each rat in control group. Rats were sacrificed at 2, 4, 8 weeks following operation and histomorphometric and radiodensitometric analysis were performed. 1. The newly formed bone length was $102.91{\pm}22.05$, $178.29{\pm}24.40$ at 2 week in the each control, experimental group, $130.95{\pm}39.24$, $242.62{\pm}50.33$ at 4 week and $181.53{\pm}76.35$, $240.36{\pm}22.00$ at 8 week($unit,{\mu}m$). In the 2, 4 week, there were statistically significant difference between control and experimental group(P<0.05). 2. The newly formed bone area was $2962.06{\pm}1284.48$, $10648.35{\pm}1284.48$ at 2 week, $5103.25{\pm}1375.88$, $9706.78{\pm}1481.81$ at 4 week, $8046.02{\pm}818.99$, $12057.06{\pm}740.47$ at 8 week($unit,{\mu}m^2$). In every week, there were statistically significant difference between control and experimental group(P<0.05). 3. The radiopacity was $14.26{\pm}.33$, $25.47{\pm}4.33$ at 2 week, $20.06{\pm}9.07$, $26.61{\pm}2.78$ at 4 week, $22.99{\pm}3.76$, $27.29{\pm}1.54$ at 8 week(unit, %). In the 2 week, there was statistically significant difference between control and experimental group(P<0.05). In conclusion, the results of the present study suggest that safflower seed extract initially has an effect on the newly formed bone area, length and radiopacity when it is applied to the calvarial defect of Sprague - Dawley rat. Then. the material has an effect on newly formed bone area and length.

• Journal of Chest Surgery
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• v.33 no.7
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• pp.531-540
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• 2000

Baclgrpimd; Recent studies have suggested that the cardioprotective effect of ischemic preconditioning(IP) is closely related to glycogen depletion and attenuation of intracellular acidosis. In the present study, the authors tested this hypothesis by perfusion isolated rabbit hearts with glucose(G) is closely related to glycogen depletion and attenuation of intracellular acidosis. In the present study, the authors tested this hypothesis by perfusion isolated rabbit hearts with glucose(G)-free perfusate. Material and Method; Hearts isolated from New Zealand white rabbits(1.5~2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45 min global ischemia followed by 120 min reperfusion with IP(IP group, n=13) or without IP(ischemic control group, n=10). IP was induced by single episode of 5 min global ischemia and 10 min reperfusion. In the G-free preconditioned group(n=12), G depletion was induced by perfusionwith G-free Tyrode solution for 5 min and then perfused with G-containing Tyrode solution for 10 min; and 45 min ischemia and 120 min reperfusion. Left ventricular functionincluding developed pressure(LVDP), dP/dt, heart rate, left ventricular end-distolic pressure(LVEDP) and coronary flow (CF) were measured. Myocardial cytosolic and membrane PKC activities were measured by 32P-${\gamma}$-ATP incorporation into PKC-specific peptide and PKC isozymes were analyzed by Western blot with monoclonal antibodies. Infarct size was determined by staining with TTC(tetrazolium salt) and planimetry. Data were analyzed by one-way analysis of variance (ANOVA) and Turkey's post-hoc test. Result ; In comparison with the ischemic control group, IP significantly enhanced functional recovery of the left ventricle; in contrast, functional significantly enhanced functional recovery of the left ventricle; in contrast, functional recovery were not significantly different between the G-free preconditioned and the ischemic control groups. However, the infarct size was significantly reduced by IP or G-free preconditioning(39$\pm$2.7% in the ischemic control, 19$\pm$1.2% in the IP, and 15$\pm$3.9% in the G-free preconditioned, p<0.05). Membrane PKC activities were increased significantly after IP (119%), IP and 45 min ischemia(145%), G-free [recpmdotopmomg (150%), and G-free preconditioning and 45 min ischemia(127%); expression of membrane PKC isozymes, $\alpha$ and $\varepsilon$, tended to be increased after IP or G-free preconditioning. Conclusion; These results suggest that in isolated Langendorff-perfused rabbit heart model, G-free preconditioning (induced by single episode of 5 min G depletion and 10 min repletion) colud not improve post-ischemic contractile dysfunction(after 45-minute global ischemia); however, it has an infarct size-limiting effect.

• Asia pacific journal of information systems
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• v.23 no.1
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• pp.87-106
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• 2013

In the service-oriented economy, knowledge and skills are considered core resources to secure competitive advantages and service innovation. Knowledge management capability, which facilitates to produce, share, accumulate and reuse knowledge, becomes as important as knowledge itself to create service value. Along with knowledge management capability, dynamic capability and operational capability are the key capabilities related to managing service delivery processes. Previous studies indicated that these three capabilities are related to service innovation. Although separately investigate the relationship between the three capabilities. The purpose of this study is 1) to define variables that have effects on service innovation including knowledge management capability, dynamic capability and operational capability, and 2) to empirically test to identify relationship among variables. In this study, knowledge management capability is defined as the capability to manage knowledge process. Dynamic capability is regarded as the firm's ability to integrate, build, and reconfigure internal and external competences to address rapidly changing environments. Operational capability refers to a high-level routine that, together with its implementing input flows, confers upon an organization's management a set of decision options for producing significant outputs of a particular type. The proposed research model was tested against the data collected through the survey method. The survey questionnaire was distributed to the managers who participated in an educational program for management consulting. Each individual who answered the questionnaire represented a knowledge based service firm. About 212 surveys questionnaires were sent via e-mail or directly delivered to respondents. The number of useable responses was 93. Measurement items were adapted from previous studies to reflect the characteristics of the industry each informant worked in. All measurement items were in, 5 point Likert scale with anchors ranging from strongly disagree (1) to strongly agree (5). Out of 93 respondents, about 81% were male, 82% of respondents were in their 30s. In terms of jobs, managers were 39.78%, professions/technicians were 24.73%, researchers were 12.90%, and sales people were 10.75%. Most of respondents worked for medium size enterprises (47,31%) in their, less than 30 employees (46.24%) in their number of employees, and less than 10 million USD (65.59%) in terms of sales volume. To test the proposed research model, structural equation modeling (SEM) technique (SPSS 16.0 and AMOS version 5) was used. We found that the three organizational capabilities have influence on service innovation directly or indirectly. Knowledge management capability directly affects dynamic capability and service innovation but indirectly affect operational capability through dynamic capability. Dynamic capability has no direct impact on service innovation, but influence service innovation indirectly through operational capability. Operational capability was found to positively affect service innovation. In sum, three organizational capabilities (knowledge management capability, dynamic capability and operational capability) need to be strategically managed at firm level, because organizational capabilities are significantly related to service innovation. An interesting result is that dynamic capability has a positive effect on service innovation only indirectly through operational capability. This result indicates that service innovation might have a characteristics similar to process innovation rather than product orientation. The results also show that organizational capabilities are inter-correlated to influence each other. Dynamic capability enables effective resource management, arrangement, and integration. Through these dynamic capability affected activities, strategic agility and responsibility get strength. Knowledge management capability intensify dynamic capability and service innovation. Knowledge management capability is the basis of dynamic capability as well. The theoretical and practical implications are discussed further in the conclusion section.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.313-324
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• 2009

We explore the effect of particle shape and size on 3-dimensional (3D) network and pore structure of porous earth materials composed of glass beads and silica gel using NMR micro-imaging in order to gain better insights into relationship between structure and the corresponding hydrologic and seismological properties. The 3D micro-imaging data for the model porous networks show that the specific surface area, porosity, and permeability range from 2.5 to $9.6\;mm^2/mm^3$, from 0.21 to 0.38, and from 11.6 to 892.3 D (Darcy), respectively, which are typical values for unconsolidated sands. The relationships among specific surface area, porosity, and permeability of the porous media are relatively well explained with the Kozeny equation. Cube counting fractal dimension analysis shows that fractal dimension increases from ~2.5－2.6 to 3.0 with increasing specific surface area from 2.5 to $9.6\;mm^2/mm^3$, with the data also suggesting the effect of porosity. Specific surface area, porosity, permeability, and cube counting fractal dimension for the natural mongolian sandstone are $0.33\;mm^2/mm^3$, 0.017, 30.9 mD, and 1.59, respectively. The current results highlight that NMR micro-imaging, together with detailed statistical analyses can be useful to characterize 3D pore structures of various porous earth materials and be potentially effective in accounting for transport properties and seismic wave velocity and attenuation of diverse porous media in earth crust and interiors.

• Polymer(Korea)
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• v.32 no.2
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• pp.103-108
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• 2008

Osmotic pellet, which consisted of water-swellable seed layer, drug layer, and porous membrane layer, has been widely utilized in oral drug delivery system. In this work, we describe the preparation of osmotic pellet with nifedipine as model drug and a mixture of cellulose acetate (CA) and Eudragit RS as membrane layer, and then examined the drug release behavior on the variation of the thickness change of membrane layer (CA and Eudragit RS) and release media. Furthermore, we examined the nifedipine release behavior using sodium alginate as a potential membrane candidate. Osmotic pellet was obtained in the quantitative yield by fluidized bed coater. Osmotic pellet exhibited the round morphology and the size ranging $1500{\sim}1700{\mu}m$ in SEM. The nifedipine release decreased as the thickness of membrane layer (CA and Eudragit RS) increased. In addition, it observed that there is difference of release amount in between intestinal juice (pH 6.8) and gastric juice (pH 1.2). In the case of osmotic pellet coated with sodium alginate, nifedipine release behavior depended on the crosslinking of sodium alginate layer. In conclusion, we found that various membrane layers could control the release amount of nifedipine.