• Journal of Periodontal and Implant Science
• /
• v.38 no.1
• /
• pp.7-14
• /
• 2008

Purpose: Chitosan & chitosan derivative(eg. membrane) have been studied in periodontal regeneration, and recently many studies of chitosan have reported good results. If chitosan's effects on periodontal regeneration are enhanced, we can use chitosan in many clinical and experimental fields. For this purpose, this study reviewed available literatures, evaluated comparable experimental models. Materials and Methods: Ten in vivo studies reporting chitosan's effects on periodontal tissue regeneration have been selected by use of the 'Pubmed' and hand searching. Results: 1. In Sprague Dawley rat calvarial defect models, amount of newly formed bone in defects showed significant differences between chitosan/chitosan-carrier/chitosan-membrane groups and control groups. 2. In beagle canine 1-wall intrabony defect models, amount of new cementum and new bone showed significant differences between chitosan/chitosan-membrane groups and control groups. The mean values of the above experimental groups were greater than the control groups. Conclusion: The results of this study have demonstrated that periodontal regeneration procedure using chitosan have beneficial effects, which will be substitute for various periodontal regenerative treatment area. One step forward in manufacturing process of chitosan membrane and in use in combination with other effective materials(eg. bone graft material or carrier) may bring us many chances of common use of chitosan in various periodontal area.

• Journal of Radiation Protection and Research
• /
• v.42 no.3
• /
• pp.158-165
• /
• 2017

Background: Nuclear facilities in South Korea have generally adopted pressurized ion chambers to measure ambient gamma ray exposure rates for monitoring the impact of radiation on the surrounding environment. The rates assessed with pressurized ion chambers do not distinguish between natural and man-made radiation, so a further step is needed to identify the cause of abnormal variation. In contrast, using NaI(Tl) scintillation detectors to detect gamma energy rates can allow an immediate assessment of the cause of variation through an analysis of the energy spectra. Against this backdrop, this study was conducted to propose a more effective way to monitor ambient gamma exposure rates. Materials and Methods: The following methods were used to analyze gamma energy spectra measured from January to November 2016 with NaI detectors installed at the Korea Atomic Energy Research Institute (KAERI) dormitory and Hanbat University. 1) Correlations of the variation of rates measured at the two locations were determined. 2) The dates, intervals, duration, and weather conditions were identified when rates increased by $5nSv{\cdot}h^{-1}$ or more. 3) Differences in the NaI spectra on normal days and days where rates spiked by $5nSv{\cdot}h^{-1}$ or more were studied. 4) An algorithm was derived for automatically calculating the net variation of the rates. Results and Discussion: The rates measured at KAERI and Hanbat University, located 12 kilometers apart, did not show a strong correlation (coefficient of determination = 0.577). Time gaps between spikes in the rates and rainfall were factors that affected the correlation. The weather conditions on days where rates went up by $5nSv{\cdot}h^{-1}$ or more featured rainfall, snowfall, or overcast, as well as an increase in peaks of the gamma rays emitted from the radon decay products of $^{214}Pb$ and $^{214}Bi$ in the spectrum. This study assumed that $^{214}Pb$ and $^{214}Bi$ exist at a radioactive equilibrium, since both have relatively short half-lives of under 30 minutes. Provided that this assumption is true and that the gamma peaks of the 352 keV and 1,764 keV gamma rays emitted from the radionuclides have proportional count rates, no man-made radiation should be present between the two energy levels. This study proved that this assumption was true by demonstrating a linear correlation between the count rates of these two gamma peaks. In conclusion, if the count rates of these two peaks detected in the gamma energy spectrum at a certain time maintain the ratio measured at a normal time, such variation can be confirmed to be caused by natural radiation. Conclusion: This study confirmed that both $^{214}Pb$ and $^{214}Bi$ have relatively short half-lives of under 30 minutes, thereby existing in a radioactive equilibrium in the atmosphere. If the gamma peaks of the 352 keV and 1,764 keV gamma rays emitted from these radionuclides have proportional count rates, no man-made radiation should exist between the two energy levels.

• Journal of The Korean Association For Science Education
• /
• v.36 no.3
• /
• pp.361-369
• /
• 2016

In this study, we investigated the characteristics of group discussion and classroom discussion in the scientific modeling of the particulate model of matter. 7th graders in Seoul participated in this study. We implemented science instructions based on the GEM cycle of scientific modeling. We analyzed the differences between group discussion and classroom discussion in three steps: exploring thoughts, comparing thoughts, and drawing conclusions. We also looked into the level of argumentations of the students in the modeling activities. The analysis of the results indicated that students generated a group model by extracting commonalities from each model of their group members, and then they evaluated and modified the group model by comparing the differences among the models in classroom discussion. The main step involved in group discussion was 'exploring thoughts', whereas in classroom discussion it was 'comparing thoughts'. Although the levels of argumentation among the students were generally low, most students participated with enthusiasm, as they expressed their interest and had positive perception in the modeling activities. As a result, the modeling activities were found to have positive influences on concept development. Some suggestions to implement the modeling activities in science teaching effectively were discussed.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.5
• /
• pp.540-548
• /
• 2012

The Weapon Target Allocation(WTA) problem is the NP-Complete problem. The WTA problem is that the threatful air targets are assigned by weapon of allies for killing the targets. A good solution of NP-complete problem is heuristic algorithms. Genetic algorithms are commonly used heuristic for global optimization, and it is good solution on the diverse problem domain. But there has been very little research done on the generation of their initial population. The initialization of population is one of the GA step, and it decide to initial value of individuals. In this paper, we propose to the population initialization method to improve a Genetic Algorithm. When it initializes population, the proposed algorithm reflects the characteristics of the WTA problem domain, and inherits the dominant gene. In addition, the search space widely spread in the problem space to find efficiently the good quality solution. In this paper, the proposed algorithm to verify performance examine that an analysis of various properties and the experimental results by analyzing the performance compare to other algorithms. The proposed algorithm compared to the other initialization methods and a general genetic algorithm. As a result, the proposed algorithm showed better performance in WTA problem than the other algorithms. In particular, the proposed algorithm is a good way to apply to the variety of situation WTA problem domain, because the proposed algorithm can be applied flexibly to WTA problem by the adjustment of RMI.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.39 no.2
• /
• pp.91-102
• /
• 2011

This study was carried out to analyze the problems on several steps of the establishment of the Nature Ecological Forest in Yeouido Park, Seoul, and also to suggest improved approaches on each step. For execution drawing, planting models and plans seemed to be uncertain, and the quantity and size of planting trees seemed to be impractical. For construction, the woody plants planted on the site were different in species and size from the planting plan. Ecological planting was somewhat limited because of the inappropriate soil properties. For management, replacement of the dead trees was not executed properly, and no management scheme was prepared after the replacement period. We suggested improved approaches for the establishment of ecological forests in urban areas as follows: for execution drawing, overstory, understory and herbaceous ground cover layers should be composed based on standard plant community structures. Trees that are available from tree markets should be specified in the planting plan. For construction, trees for planting need to be tagged to identify species and size. When tree species and size are changed, they should be checked to ensure that they are proper to the plant community model. Soil information should be collected to check that they fit the target plant community model. For management, the proper amount of trees needs to be specified in the planting plan by applying regular discount rates, especially for trees supplied from the government sector. The replacement period should be extended from two years to five years. The change of plant communities should be monitored during first five years after establishment.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.12
• /
• pp.2351-2357
• /
• 2008

Noninvasive radial artery pulse wave has been widely used not only for the pulse wave analysis(PWA) itself but also for assessment of arterial stiffness with estimated aortic pulse wave from peripheral pulse wave. However, it has been found that the deformation of pulse shape can be caused readily by changing measuring position, indentation pressure, and so on. So, in this study, we have developed a system which can measure radial pulse wave and skin displacement simultaneously while the indentation body goes down to occlude subject's radial artery. This system can be divided into a measuring apparatus part, an indentation control hardware part, a data acquisition part and a control and computation part. And, the measuring apparatus consists of an arm-rest, a step motor, an indentation body, a laser displacement sensor(LK-G30, Keyence Co.) and pulse wave sensor. Under load-free condition and radial artery loaded condition, the evaluation of developed system has been performed. From these results, we can conclude: 1) The developed system can control the indentation body quantitatively and the adopted laser displacement sensor shows linear output characteristic even with skin as a reflector. 2) This system can measure the pulse wave and the displacement of indentation body, that is, skin displacement simultaneously at each specific level of indentation body. 3) This system can provide the number of motor steps used to get down the indentation body, the measured skin displacement, the calculated indentation pressure, the calculated pulse pressure and the pulse waveform as well as the information generated by combining these with each others. 4) This system can reveal the relationship between the morphological changes of pulse wave and the estimated displacement of radial artery wall by indentation. Consequently, the developed system can furnish more abundant information on radial artery than previous diagnosis systems based on tonometric measurement. In further study, we expect to setup the standard measuring process and to concrete the algorithm for the estimation of radial artery's diameter and of displacement of radial artery's wall. Furthermore, with well designed clinical studies, we hope to turn out the usefulness of developed system in the field of cardiovascular system evaluation.

• KSBB Journal
• /
• v.10 no.4
• /
• pp.349-356
• /
• 1995

To produce PHA(polyhydroxyalkanoic acid) from microbr, dozens of microorganism have been screened from sewage sludge. Selected a strain HJ out of 50 strains of PHA producing bacteria has a capability of accumulating large amounts of PHB/HV copolymer when grown in batch culture with a single carbon source (glucose) that was not generally considered as precursor of hydroxyvalerate monomer unit. The strain HJ was identified as the genus Pseudomonas with respect to morphological, cultural, and biochemical characteristics. The optimal temperature and pH for cell growth were $37^{\circ}C$ and 7.0. The optimal medium compositions for cell growth were glucose 1% as a carbon source, (NH4) 2SO4 0.2% as a nitrogen source, K2HPO4 0.3%, and KH2PO4 0.45%. TO investigate she optimal condition for PHA production two-step cultivation method was employed. PHA production was inducted by deficiency of NH4+, SO4-2, Mg+2. Besides carbon source, deficiency of all nutrients stimulated PHA productivity but deficiency of NH4+ stimulated the most HV monomer content. The highest PHA production was C/N molar ratio 95.2. Pseudomonas sp. HJ was also able to pyoduc PHB/HV copolymer when cultivated on alkane, alkanoate, alcohol as carbon sources. The contents of PHA and she proportions of hydroxyvalerate monomer units varied depending on the carbon sources. Especially Pseudomonas sp. HJ was able to incorporate hydroxyvalerate into PHB/HV to level as high as from 49 to 74 mol% when grown in a medium containing hexadecane and propionate. The purified PHA was identified PHB/HV copolymer by HNMR analysis.

• The Journal of Fisheries Business Administration
• /
• v.30 no.1
• /
• pp.119-147
• /
• 1999

This article is subject to the rationalization of the cold-storage warehouse management, which gives the stabilization of the fishery production and the food life with respect to fisheries industry. In this point of view, the article examines to the structure of the cold-storage warehouse industry from the perspective of the industrial organization. To put it concretely, the article intends to apprehend the state of the structure of the industry and analyze the cold-storage warehouse's management activities. In addition, I try to find know the factors that affect the management performance(profitablity) of the industry through the cross-sectional correlation analysis. Finally, the conclusion of the article can be described as follows : \circled1 On the basis of the cold-storage capacity, there is the tendency that the industry concentrate in the area of Pusan(41.7%). \circled2 By formulating step of development of the industry, it is divided by six types. Type I is designed as raw material-storage warehouse for self-processing. Type IIis the raw material-storage warehouse for self-processing and storage-sale warehouse. Type III is the raw material-storage warehouse for self.distribution. Type IV is the raw material-storage warehouse for self-distribution and storage-sale warehouse. Type V is the net storage-sale warehouse. Type Ⅵ is the physical distribution center warehouse. Although each region has one representative type,6 types exist in all regions. \circled3 The competition structure of the industry has double structure on the basis of cold-storage capacity. \circled4 With respect to the management activity of the cold-storage warehouse, there is no change or even a decrease not increasing or not any change in sales from 1996 to 1997 \circled5 In order to try to induce the amount of shipper's materials, services that a cold-storage warehouse supply with its users include a custody-fee discount, a distribution-process service, a finance service, quality management service and so on. One of the best attractive services is the custody-fee service. \circled6 In the structure and management activity of the industry, the factors that affect management performance (profitablity) are a custody-fee discount, sales ability and capital structure of individual firm. Positive factor is sales ability and capital structure of individual firm. But, The custody-fee discount turns out to be a negative capital structure of individual film.

• Korean Journal of Child Education & Care
• /
• v.17 no.2
• /
• pp.99-114
• /
• 2017

This study investigated the affects of Parent-child interaction, peer interaction and teacher-child interaction on kindergartners' social competence, language and literacy Ability. Participants were 1203 children attending panel study on Korean children. It used the 'Social Competence Inventory', 'SECCYD', 'HEQ', 'PIPPS' and the 'Teacher-Child Relation Scale' in collection of data. Collected data were analyzed through the SPSS 18.0 program and pearson's correlation and step-wise multi regression analysis. Findings are as follows. First, there were positive correlations between children's social competence and parent-child interaction, peer interaction and teacher-child interaction. Second, there were positive correlations between children's language and literacy ability and peer interaction and teacher-child interaction. Third, Parent-child interaction, peer interaction were predictable variable affecting the young children's social competence. Fourth, peer interaction and teacher-child interaction were found to be predictable variables affecting the young children's language and literacy ability.

• Sijohaknonchong
• /
• v.20
• /
• pp.97-111
• /
• 2004

It is extremely crucial in academic researches to clarify exact spellings and original contents of the works under analysis. In the case of Sijo, the works in different collections of poems with the same title prove to have been transformed in its spellings and expressions through the long period. Therefore it has been a very important step which should be taken prior to a research of Sijo that spellings and expressions of those works be compared and checked. In this point of view, I believe the book titled A Full Collection of Sijo. Yokdae Sijojunseo, written by me can be of great help to identify the expressions and contents. Moreover this book enables us to check authors and melodies of the works. This is a study on the aspects and phases of transformation of an original work by examining 'Eobusasisa'. The findings are the following: first of all, the number of collections including 'Eobusasisa' is unexpectedly small; secondly, how the original work was transformed and modified in various collections. A representative collection including 'Eobusasisa' as a transformed style into Sijo is Haedonggayo, where 38 poems out of 40 of 'Eobusasisa' are collected. All the modifications and changes have been checked in this study. To sum up, it is very important to compare the variations of a Sijo work with each other. It enables us to check up and to identify the writers, spellings, expressions, and melodies.