• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.599-611
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• 2000

Alveolar crest is the section of interproximal alveolar bone which includes the free edge of the alveolar process. An increase of the normal forces within limits of tolerance leads to deposition of new bone. If forces are beyond the limits of tolerance, resorption of bone will result whether the force produces pressure or tension. This study was designed to evaluate changes of alveolar bone levels in mesial and distal surface of the left, right first molar, by using pre-treatment, post-treatment panorama films. Two hundreds sixteen subjects were divided into adolescent group of 104 subjects and adult group of 112 subjects, to which orthodontic treatment with a bicuspid extraction (adolescent group-50 subjects, adult group-50 subjects) or without a nonextraction (adolescent group-54 !subjects, adult group-62 subjects) was applied by fixed appliances. Pre- and post-treatment Panorama films were traced, and alveolar crest height was measured. Amounts of changes in alveolar crest height by treatment were calculated md compared in terms of side of tooth, extraction, age. The results were as follows ; 1. When pre-treatment alveolar crest bone levels were compared, levels of adult group were significantly lower than those of adolescent group. 2. Post-treatment alveolar crest bone levels were significantly lower than pre-treatment levels. 3. When changes of alveolar crest height were compared, between adolescent and adult group were not significantly. 4. When changes of alveolar crest height were compared, significantly larger changes were noticed in ex윤action than nonextraction cases. 5. When changes of alveolar crest height were compared, significantly larger changes were noticed in maxilla than mandible. 6. When mesio-distally compared, significantly larger changes were observed in the distal than mesial sides of adult group.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.1
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• pp.66-76
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• 2016

Determination of type of a vehicle is being used in various areas such as collecting tolls, collecting statistical traffic data and traffic prognosis. Because most of the vehicle type classification systems depend on vehicle length indirectly or directly, highly reliable automatic vehicle length measurement system is crucial for them. This study makes use of a pencil beam laser rangemeter and devises a mechanical device which rotates the laser rangemeter. The implemented system measures the range between a point and the laser rangemeter then indicates it as a spherical coordinate. We obtain several silhouettes of cross section of the vehicle, the rate of change of the silhouettes, signs of the rates then squares the rates to apply cell averaging constant false alarm rate (CA-CFAR) technique to find out where the border is between the vehicle and the background. Using the border and trigonometry, we calculated the length of the vehicle and confirmed that the calculated vehicle length is about 94% of actual length.

• Journal of Engineering Education Research
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• v.2 no.1
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• pp.39-50
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• 1999

In recent globalization era, Korean architectural education and profession are emerging as the fields with serious problems. There are two major reasons. One is an internal factor caused by Ministry of Education's full scale shift from department to faculty system. Due to the drastic change in this system, most of schools have serious difficulties to deliver the proper professional education. And the other is an external factor. In WTO era, Union of International Architects has adopted $\ulcorner$UIA Accord on Recommended International Standards of Professionalism In Architectural Practice$\lrcorner$. According to the education section of the Accord, it requires 5 years of professional education in the accredited school. So, if it is formally adopted in the Beijing Congress, which is scheduled to be held in June 1999, we may face very serious problems in architectural education. As mentioned above, with the present education system it is believed not easy to meet their new criteria. Within the present system, which does not have any mandatory relationship with professional licence, students might go on to diverse fields such as architectural design, structural engineering, construction management and building equipment engineering. However, if UIA Accord and Engineering Accreditation are required at the same time, it will not be easy to meet their new criteria with present architectural education system. The goal of this paper is to suggest the models to meet the standards of international community while keeping the strengths of existing systems.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.81-90
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• 1998

Electromagnetic waves may induce various effects on nervous tissues either by thermal or non-thermal mechanisms. This paper intoduces a method to evalute the non-thermal effect to central nervous system by measuring the EEGs of the rabbits treated by nimodipine before exposed to weak microwave field. 20 rabbits were divided into 2 groups and their EEGs were measured after their head section were exposed to 2,450 MHz microwave with the power density of 10 dBm and 20 dBm respectively for 10 minutes and compared with those of the 3rd group of 10 rabbits which were not exposed. The 4th group of 10 rabbits were intravenously given with nimodipine before exposed to 20 dBm field to determine whether this drug would reverse the EEGs changes induced by weak microwave irradiation. As field poser exceeded 20 dBm although no significant physiological changes were observed, total induced EEGs power was remarkably decreased suggesting the presence of CNS activation. Using Fourier analysis on the EEGs signal it was found that remarkable decrease in delta band and increase in the alpha and beta bands in a significant manner(P<0.05) compared to control group. The changes were, however, not reversed by nimodipine-treatment. The effects may be pure thermal in nature because no significant change has been observed in nimodipine treated rabbits.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.12
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• pp.1768-1774
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• 2012

This study was conducted to evaluate methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from livestock agriculture in 16 local administrative districts of Korea from 1990 to 2030. National Inventory Report used 3 yr averaged livestock population but this study used 1 yr livestock population to find yearly emission fluctuations. Extrapolation of the livestock population from 1990 to 2009 was used to forecast future livestock population from 2010 to 2030. Past (yr 1990 to 2009) and forecasted (yr 2010 to 2030) averaged enteric $CH_4$ emissions and $CH_4$ and $N_2O$ emissions from manure treatment were estimated. In the section of enteric fermentation, forecasted average $CH_4$ emissions from 16 local administrative districts were estimated to increase by 4%-114% compared to that of the past except for Daejeon (-63%), Seoul (-36%) and Gyeonggi (-7%). As for manure treatment, forecasted average $CH_4$ emissions from the 16 local administrative districts were estimated to increase by 3%-124% compared to past average except for Daejeon (-77%), Busan (-60%), Gwangju (-48%) and Seoul (-8%). For manure treatment, forecasted average $N_2O$ emissions from the 16 local administrative districts were estimated to increase by 10%-153% compared to past average $CH_4$ emissions except for Daejeon (-60%), Seoul (-4.0%), and Gwangju (-0.2%). With the carbon dioxide equivalent emissions ($CO_2$-Eq), forecasted average $CO_2$-Eq from the 16 local administrative districts were estimated to increase by 31%-120% compared to past average $CH_4$ emissions except Daejeon (-65%), Seoul (-24%), Busan (-18%), Gwangju (-8%) and Gyeonggi (-1%). The decreased $CO_2$-Eq from 5 local administrative districts was only 34 kt, which was insignificantly small compared to increase of 2,809 kt from other 11 local administrative districts. Annual growth rates of enteric $CH_4$ emissions, $CH_4$ and $N_2O$ emissions from manure management in Korea from 1990 to 2009 were 1.7%, 2.6%, and 3.2%, respectively. The annual growth rate of total $CO_2$-Eq was 2.2%. Efforts by the local administrative offices to improve the accuracy of activity data are essential to improve GHG inventories. Direct measurements of GHG emissions from enteric fermentation and manure treatment systems will further enhance the accuracy of the GHG data.

• Journal of Aquaculture
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• v.8 no.4
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• pp.251-260
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• 1995

Experimental transportations of the olive flounder (Paralichthys olivaceus) seedlings (body weight $2.1\pm0.39g$) with polyethylene vinyl bag were Performed to study the change of dissolved oxygen (DO) during transportation, survival rate and feeding activity of seedlings after transportation. The distance and time required for the transportations were 272 km and 11 hours, respectively. DO was rapidly decreased within 3 hours (P<0.05) during the transportation of seedlings of 40 fish in 10l of sea water at $15.6\~17.8^{\circ}C$ of initial water temperature with 5 ml/l of initial DO. The decreasing tendency of DO (Y) according to elapsed time (X) was expressed an equation of $Y\;=\;2.7444X^{-0.4780}$ (r=0.8071). Feeding activity of the seedlings after transportation supplemented with oxygen and icepack besides above transport conditions was significantly higher than that of fish supplemented with icepack only (P<0.05). It was desirable to starve the seedlings for 36 hours before transportation. Survival rate of seedlings was greatly reduced, when the dissolved oxygen concentration was lowered below the range of $0.7\~0.94ml/l$ just after transportation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6D
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• pp.755-764
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• 2011

At the present, planning and installation of parking space sections and lane width are implemented in accordance with the installation standard and parking lot structure by the enforcement regulations of the Parking Act. While large and RV (Recreational Vehicle) vehicles have increased in number recently, parking is complex with improper installation standards. It causes serious problems, including vehicle vandalism, increased civil complaints, travel inconveniences for parking lot users, management and maintenance issues for parking lots, and so forth. The study, therefore, determined that the practical and appropriate realignment of parking unit adjustment and lane width regulations are essential. The study conducted prior review on domestic parking sections and change cases of composition by vehicle types, including the component ratio of domestic and foreign vehicles, width of vehicle by types in order to examine the parking problems that account for a increasing social issues, and provided parking plan methods by types of vehicle, as well as reform and reaction plans for parking unit adjustment and lane width considering security and smooth traffic flow. After comparing and analyzing between estimated installation of parking space and lane width and internal and external cases, the study suggests the improvement that considers expenses and convenience of a driver. Also, it shows installation of parking space that considers traffic safety, improvement of lane width, and parking way depends on vehicle types. By providing estimation for parking planning and parking planning methods that secure safe and smooth traffic flow within a parking lot, the study will contribute to the development of improved alternatives for cost-effective traffic safety and set-up structure, including installation standards of parking lots.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.25-34
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• 2017

The objective of this study is to seek for improvement measures to make the Ecosystem and Nature Map by analyzing causes for grade changes and distributional characteristics of areas with public objections to the Ecosystem and Nature Map notified by e-official gazette from 2014 to June 2016. The receipt of public appeals has been recently increased from average 23 cases a year(2007-2013) to average 33 cases a year(2014-June 2016) while there were 42 areas with public appeals for less than the minimum area($62,500m^2$) for the evaluation of grade of the Ecosystem and Nature Map. Most of the public appeals focused on the 1st grade zone of the Ecosystem and Nature Map. Before grade changes by public appeals, the 1st grade zone of the Ecosystem and Nature Map were 76.0% of the whole areas with public appeals. However, after grade changes by public appeals, it was rapidly decreased to 25.2%, which means that a lot of the 1st grade zone with public appeals were lowered. In the results of analyzing the distributional characteristics of areas with public appeals, they were mostly distributed in lowland(less than 250m altitude), section with $10{\sim}20^{\circ}$ slope, and areas close to or within 100m from built-up area. Regarding areas with public appeals, the biggest time difference between the period of the existing research by National Ecosystem Survey and the period of notice after completing the treatment of public appeals was 18 years while areas showing 6-15 years of time difference were about 70%. Thus, there were huge differences in time of research and notice. Also, the biggest causes for grade changes were boundary errors caused by small-scale survey, and then followed by changes in evaluation of endangered species and occurrence of built-up area and damaged land. Analyzing areas with public appeals in each evaluation item of the Ecosystem and Nature Map, vegetation part was 73.0%, and endangered species area was 23.1% while topography and wetland was less.

• Economic and Environmental Geology
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• v.45 no.5
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• pp.565-578
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• 2012

Sedimentary facies of the Middle to Upper Cambrian Sesong Formation, Taebacksan Basin, are analyzed using detailed field mapping and stratigraphic section measuring. As a result, five sedimentary facies are recognized in the formation, which include lime nodule bearing shale facies, anastomosing wackestone-packstone facies, well-laminated siltstone facies, fine to medium sandstone facies and lime pebble conglomerate facies. Together with sedimentary facies analysis, study on vertical facies variation indicates that the Sesong Formation was deposited in an outer to inner shelf during relative sea-level fall. Especially, shallow marine aspects of the upper part of the Sesong Formation including 10-m-thick, fine to medium-grained sandstones appear to be very similar with the shallow marine strata accumulated during the Steptoean Stage (Dunderbergia) in Laurentia. These lithofacies comparisons of coeval strata between two continents suggest that sedimentation in the Sesong Formation reflects the influence of global sea-level fall occurred during the late Middle Cambrian to early Late Cambrian. As well, a stratigraphic discontinuity surface that may have sequence stratigraphic significance is recognized within the shallow marine sandstone beds of the uppermost Sesong Formation. This stratigraphic discontinuity surface may correspond to the Sauk II-III sequence boundary in Laurentia. Therefore, results delineated in this study will use a new stratigraphic paradigm for regional correlation of the Middle to Late Cambrian strata (e.g., the Sesong Formation) in the Taebacksan Basin, and will provide very useful information on intercontinental stratigraphic correlation in the future.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.780-790
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• 2020

In this study, the cell-wall microstructure and anti-swelling effectiveness (ASE) of heat-treated larch wood were evaluated and the correlation between them was analyzed. For this purpose, some larch lumbers were heat-treated for 12, 18, and 24 hours at temperatures of 190℃ and 220℃. By observing the scanning electron microscopy cross-sectional image of the heat-treated larch, it was confirmed that the shape of heat-treated wood cell changed, the cut-section of the wood cell wall was rough, and the intercellular space has become wide as the intercellular bonds had broken because of heat-treatment. In addition, the evaluation of the swelling for each treatment condition revealed that, as the heat-treatment temperature and duration increased, the amount of absorbed water and swelling decreased and the ASE increased. The decrease in the amount of absorbed water is thought to be affected by the chemical change in the cell wall by heat-treatment. On the contrary, the decrease in the swelling and the increase in the ASE are thought to be due to a combination of chemical changes and physical changes such as structural changes in the cell wall.