• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.5
• /
• pp.417-422
• /
• 2010

Introduction: Bone density is one of the important factors for the long term success of endosseous implants. The bone density varies from site to site and from patient to patient. A preoperative evaluation of the bone density is quite useful to oral surgeons for planning dental implantation. More accurate information on the bone density will help surgeons identify suitable implant sites, thereby increase the success rate of dental implantation. This study examined the correlation between the bone density measured preoperatively by computed tomography (CT) and the implant primary stability measured by resonance frequency analysis. Furthermore, the effects of the implant sites, gender, age and generalized systemic disorder patients on the bone density and primary implant stability were examined. Materials and Methods: One hundred and fourteen patients were selected. None of the patients had undergone a tooth extraction or bone graft history in the previous year. Preoperatively, the patients underwent CT scanning to evaluate the Hounsfield unit (HU), and resonance frequency analysis (RFA) was used to evaluate the implant primary stability at the time of implant installation. All implants were 4.0 mm diameter and 11.5 mm length US II. All patients were recorded and the HU and implant stability quotient (ISQ) value were evaluated according to the sites, gender and age. Results: The highest HU values were found in the mandibular anterior site ($827.6{\pm}151.4$), followed by the mandibular molar site ($797{\pm}135.1$), mandibular premolar site ($753.8{\pm}171.2$), maxillary anterior site ($726.3{\pm}154.4$), maxillary premolar site ($656.7{\pm}173.8$) and maxillary molar site ($621.5{\pm}164.9$). The ISQ value was the highest in the mandibular premolar site ($81.5{\pm}2.4$) followed by the mandibular molar site ($80.0{\pm}5.7$), maxillary anterior site ($77.4{\pm}4.1$), mandibular anterior site ($76.4{\pm}11.9$), maxillary premolar site ($74.2{\pm}14.3$) and maxillary molar site ($73.7{\pm}7.4$). The mean HU and ISQ value were similar in females and males. (HU: P=0.331, ISQ: P=0.595) No significant difference was also found in the age group respectively. However, the correlation coefficients between the variables showed a closed correlation between the HU and ISQ value. Conclusion: These results showed close correlation between the bone density (HU) and primary stability value (ISQ) at the time of implant installation (Correlation coefficients=0.497, P<0.01). These results strengthen the hypothesis that it might be possible to predict and quantify the initial implant stability and bone density from a presurgical CT diagnosis.

• Journal of The Korean Association For Science Education
• /
• v.34 no.5
• /
• pp.499-510
• /
• 2014

The purpose of this research is to understand interactive learning during docent-led tours in a science museum focusing on scaffolding. We developed a scaffolding framework by collating the work of other researchers in related fields. The results show that scaffolding included three dimensions: purpose, interaction, and domain. The purpose dimension, divided into six categories, is related to the intention of the scaffolder and what the scaffolding are for: strategic, social, procedural, conceptual, verbal, and metacognitive. The interaction dimension reflects students' interaction with the scaffolder in two ways: dynamic (situation specific) and static (planned in advance). The domain dimension is related to two contents: domain-general and domain-specific (such as science). The scaffolding framework was applied to dynamic interactions between docents and visitors. The data was collected from elementary school students' family visits with the guidance of two docents at the Seodaemun Museum of Natural History. The data collected consisted of surveys, interviews, video-recordings, and transcripts. The analysis shows that five guiding contexts and scaffolding phases were recognized; 1) strategic scaffolding in a poorly illustrated exhibit; 2) conceptual scaffolding in a thoroughly explanative exhibit; 3) verbal scaffolding in misleading interpretation; 4) procedural scaffolding in a manipulative exhibit; and 5) metacognitive scaffolding with inaccurate content. In addition, the results show that the docents used the dynamic and static scaffolding synthetically so that the docent-led tour was effective. In conclusion, this study presents the usefulness of understanding visitors' science learning through the scaffolding framework, as well as the how docents can scaffold actively.

• Journal of the Economic Geographical Society of Korea
• /
• v.14 no.3
• /
• pp.419-436
• /
• 2011

Korean farm villages are locked in vicious circle, as lots of their problems related to low income and hollow matters are geared and multiply. To get over those problems, various plans to develop Korean farm villages are being pushed ahead. In addition, since the early of 1990s, Korea has been projects to develop settlement zones and culture villages. It has been also preceeding with a comprehensive development project of farm villages and a new vitalizations project, etc. All of these projects aim to reorganize and expand life environments, industrial bases, and convenience and welfare facilities. The existing studies on a comprehensive project to develop farm villages have been focusing on evaluation indexes, problems, investment priorities, etc. But in fact, studies on a comprehensive development project of farm villages are not thoroughgoing enough in aspects of residents' attitude and their recognition on the influence on tourist development. Thus, this study aims to present strategic schemes to allow residents to actively participate in a stage of promoting a comprehensive development project of farm villages, a stage of making the plan, and a stage of the implementation. For this, this study analyzes a comprehensive development project of farm villages and attempts to figure out which influence the tourist development in farm villages has on residents' attitude and recognition resulting from changes in economic, social cultural, and environmental aspects. Especially, this study previously examines what influential factors there exists are and what influences the development of farm villages has on residents. Based on the results from the above analysis, schemes to enable residents to actively a comprehensive development project of farm villages are presented as follows. First, it is necessary to raise our recognition on tourism and tourism development of farm villages. If the main theme of a comprehensive development project of farm villages intends farm village development, it is required to educate residents and let them clearly raise their recognition on tourism, and the effect of the project is guaranteed. Second, it is highly required to make a plan so that we can feel economic effects of revenues through project promotion and positive effects including the expansion of infrastructures and welfare facilities, etc. Third, it is necessary to bring into relief the positive recognition and attitude of a comprehensive development project of farm villages. As for the negative recognition and attitude, it is very important to change negative residents' recognition to the positive direction and to allow them to participate in and to take an interest in the project, so that the project can be effectively promoted.

• The Journal of Engineering Geology
• /
• v.19 no.1
• /
• pp.71-79
• /
• 2009

Step-drawdown tests were conducted at four pumping Wells, two in porous media and two in fractured rocks, respectively. In general, P = 2.0 suggested by Jacob (1947) is applied to porous media and fractured rocks in terms of drawdowns of step-drawdown test. In an attempt to review problems of linear model (Jacob's graphic method) in interpreting the step-draw down test, the outcomes of well parameters (aquifer loss coefficient (B), well loss coefficient (C) and well loss exponent (P)) calculated from linear and nonlinear model (Labadie and Helweg's least-squares method) were compared and analyzed. The values of C and P calculated from linear and nonlinear models differed according to permeability of aquifer and the conditions of pumping well. The value C obtained from nonlinear models in porous media and fractured rocks is about $10^0{\sim}10^{-2}$ and $10^{-3}{\sim}10^{-6}$ times lower than in their linear models, respectively. The value P of porous media obtained from nonlinear model ranged from 2.123 to 2.775, while it ranged from 3.459 to 5.635 for fractured rocks. In case of nonlinear model, well loss highly depends on the value P. At this time, well efficiencies calculated from linear and nonlinear models were $1.56{\sim}14.89%$ for porous media and $8.73{\sim}24.71%$ for fractured rocks, showing a significant error according to chosen models. In nonlinear model, it was found that the regression analysis using the least squares method was very useful to interpret step-drawdown test in all aquifer.

• Horticultural Science & Technology
• /
• v.29 no.5
• /
• pp.420-432
• /
• 2011

Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.

• Korean Journal of Ecology and Environment
• /
• v.40 no.1
• /
• pp.130-142
• /
• 2007

This study was to examine impacts of turbid water on fish community in the downstream of Yongdam Dam during the period from June to October 2006. For the research, we selected six sampling sites in the field: two sites were controls with no influences of turbid water from the dam and other remaining four sites were the stations for an assessment of potential turbid effects. We evaluated integrative health conditions throughout applications of various models such as necropsy-based fish health assessment model (FHA), Index of Biological Integrity (IBI) using fish assemblages, and Qualitative Habitat Evaluation Index (QHEI). Laboratory tests on fish exposure under 400 NTU were performed to find out impact of turbid water using scanning electron microscope (SEM). Results showed that fine solid particles were clogging in the gill in the treatments, while particles were not found in the control. This results indicate that when inorganic turbidity increases abruptedly, fish may have a mechanical abrasion or respiratory blocking. The stream health condition, based on the IBI values, ranged between 38 and 48 (average: 42), indicating a "excellent" or "good" condition after the criteria of US EPA (1993). In the mean time, physical habitat condition, based on the QHEI, ranged 97 to 187 (average 154), indicating a "suboptimal condition". These biological outcomes were compared with chemical dataset: IBI values were more correlated (r=0.526, p<0.05, n=18) with QHEI rather than chemical water quality, based on turbidity (r=0.260, p>0.05, n=18). Analysis of the FHA showed that the individual health indicated "excellent condition", while QHEI showed no habitat disturbances (especially bottom substrate and embeddeness), food-web, and spawning place. Consequently, we concluded that the ecological health in downstream of Yongdam Dam was not impacted by the turbid water.

• Korean Journal of Soil Science and Fertilizer
• /
• v.35 no.2
• /
• pp.69-76
• /
• 2002

To study the behavior of $NH_4{^+}$ of CMS (condensed molasses solubles) in soil, a laboratory incubation experiment was conducted during a period of up to 21 days at $25^{\circ}C$. The $NH_4{^+}$ of CMS was labeled with $^{15}N$ and was applied to water-unsturated and water-saturated conditions. Soil pH was gradually decreased from 6.1 to 5.4 under unsaturated condition. However, soil pH was increased to 6.5 within 2 days under saturated condition and then was constant. The concentration of ammonium was decreased 3 times faster under unsaturated condition than under saturated condition. The concentration of nitrate was increased from 17.4 to $155.4mg\;kg^{-1}$ under unsaturated condition. But concentration of nitrate was kept with low(below $8.0mg\;kg^{-1}$) under saturated condition. During the incubation, 52.4% of $^{15}NH_4{^+}$ applied was existed in the form of $NO_3{^-}$ by nitrification under unsaturated condition. Most of applied nitrogen was immobilized within 4 days of incubation. On 21 days of the incubation the percentage of immobilized nitrogen derived from $^15NH_4{^+}$(NDFA) was 19.6% under unsaturated condition and 17.0% under saturated condition. The percentage of unaccounted N, which was lost by denitrification, was 28.4% under unsturated condition and 67.6% under saturated condition.

• Journal of agricultural medicine and community health
• /
• v.35 no.3
• /
• pp.287-300
• /
• 2010

Objectives: We identified factors associated with any participation and with "good participation" (as assessed by frequency of attendance) in health promotion programs at a public health center in Korea. Methods: The subjects included 199 women who attended a baseline examination of health promotion programs during the first half of 2009. We collected data by structured interviews and physical examinations. Participation status was quantified by the frequency of attendance to the program. We classified the subjects as non-participants (0) and participants (1+ times), and as poor participants (0-29 times) and good participants (30+ times). Results: Of the 199 subjects, there were 57 (28.6%) non-participants, while 56 (28.1%) were classified as good participants. The factors that significantly affected participation status, as identified by univariate analysis, were personal factors (age, educational level, marital status, religion, living with someone, monthly income), environmental factors (method of access, accessibility of other facilities), body mass index, hypertension, perceived barriers to health, emotional salience, affectionate domain of social support, and depression. Multiple logistic regression analyses indicated that method of access was the most significant factor affecting participation in the health promotion program, and that the factors most highly associated with good participation were emotional salience, hypertension and body mass index. Conclusions: Our findings suggest that specific factors determine and enhance participation in health promotion programs offered by public health centers. These factors should be considered during the design and evaluation of health promotion programs that are offered by public health centers.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.39 no.3
• /
• pp.39-50
• /
• 2011

This study furnishes basis data for plan foundation and proper valuation of view by presenting objective and concrete selection standards and ways of Landscape Control Point(LCP) on valuation of development projects. To sum up the results of study, it establishes the prospect, publicity and direction of view as a selection standard LCP on precedent studies. The prospect, which includes visual range, direction of view, geographical features, and visibility, sets up as a valuation basis picking out the available places which have alterations according to direction and distance in practice. In the case of publicity, to select the place as there presentative area where public activities often happen than others, thirteen evaluation indexes including administration facilities, educational facilities, commercial facilities and so on. And variation of landscape is set up as an assessment index to know how much the land has changed from the beginning to the end of development. To apply the selection standards to sample places, the preliminary LCP is founded by analyzing both the prospect and published; a series of courses for selecting the final LCP is founded by analyzing the preliminary LCP and variableness of landscape on a basic of placed which have many alterations of view. At last, in the case of a selection system for LCP, the preliminary LCP is founded by analyzing both the prospect and publicity; a series of courses for selecting the final LCP is found by analyzing the preliminary LCP and variableness of landscape. Applying selection standards and the assessment index to the Sam-deok 3 residence improvement area, in the case of prospect, the southern distant view area has the largest extent. Next, the results of the assessment using the system of publicity show that a five-lane road is taking up the largest area. Hence, a total of 48 preliminary LCPs are set up by analyzing both the prospect and publicity. The results of analyzing landscape variation, one of the valuation indexes, show that Sam-deok dong around the post office has the highest rate of variation at 28.07%. Finally, three LCPs in each part, which are close range, middle range and distance view, are selected; thus, a total of nine LCPs are selected. The selected LCPs that go through a series of practical courses like a GIS program have a lot of professional opinions and are expected to secure objectivity of landscape assessment.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.39 no.3
• /
• pp.98-106
• /
• 2011

This study was performed with the purpose of providing basic data for the improvement of zoning regulations of urban nature park by analyzing the present problem which occurred during last 6 years from the year of 2005 when the program was introduced for the first time. The study was processed first by the analysis of the cases of problems evoked by citizens, second the other problems was delineated by interviews of officials, at last the validity of all of the problems was verified by a group of professionals through delphi method. The results can be summarized as follows. 1. In relation to the designation and management of urban national park areas, designation criteria, designation process, maintenance, laws and regulations and 20 other items were found to be problematic. After Delphi method, 5 items were removed and 2 added. The results showed that there were 17 problematic items in total. 2. Regarding the problem of criteria for designation, which are, lack of priority(weights), lack of objectivity due to the difficulty to use quantitative evaluation method, incompatibility for contaminated land environmental impact assessment, incompatibility of land suitability assessment, lack of detailed field survey standards, lack of national park area standards, and 6 other items. 3. Regarding the problem of designation process, which are, the occurrence of civil appeals for designating a new national park, the needs of feasibility study on the urban national park areas constructed before urban national park guidelines came out, lack of a comprehensive review of the boundaries set when determining national park area management plan, poor temporal and financial conditions for an accurate field survey, and 4 other items. 4. Regarding the problem of maintenance management, which are, lack of management system in each space, lack of effectiveness of Urban Nature Park Area Management Plan among master plans for park and green areas, the occurrence of dual managers due to dual natures such as purpose area and city park, lack of professional manpower to manage park areas, and 4 other items. 5. Regarding the problems of regulation guidelines, which are, lack of separate urban park area management plan, incompatibility of the permitted facilities in the park to the park area standards, lack of feasibility study on urban park areas, and 3 other items.