• Education of Primary School Mathematics
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• v.15 no.2
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• pp.159-170
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• 2012

Many obstacles have been found in the learning of ratio and rate. The types of epistemological obstacles concern 'terms', 'calculations' and 'symbols'. It is important to identify the epistemological obstacles that students must overcome to understand the learning of ratio and rate. In this respect, the present study attempts to figure out what types of epistemological obstacles emerge in the area of learning ratio and rate and where these obstacles are generated from and to search for the teaching implications to correct them. The research questions were to analyze this concepts as follow; A. How do elementary students show the epistemological obstacles in ratio and rate? B. What is the reason for epistemological obstacles of elementary students in the learning of ratio and rate? C. What are the teaching implications to correct epistemological obstacles of elementary students in the learning of ratio and rate? In order to analyze the epistemological obstacles of elementary students in the learning of ratio and rate, the present study was conducted in five different elementary schools in Seoul. The test was administered to 138 fifth grade students who learned ratio and rate. The test was performed three times during six weeks. In case of necessity, additional interviews were carried out for thorough examination. The final results of the study are summarized as follows. The epistemological obstacles in the learning of ratio and rate can be categorized into three types. The first type concerns 'terms'. The reason is that realistic context is not sufficient, a definition is too formal. The second type of epistemological obstacle concerns 'calculations'. This second obstacle is caused by the lack of multiplication thought in mathematical problems. As a result of this study, the following conclusions have been made. The epistemological obstacles cannot be helped. They are part of the natural learning process. It is necessary to understand the reasons and search for the teaching implications. Every teacher must try to develop the teaching method.

• Therapeutic Science for Rehabilitation
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• v.8 no.1
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• pp.51-62
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• 2019

Objective: To develop and verify the usability of a cognitive rehabilitation system with diverse cognitive functional levels based on tangible objects for the elderly population. Methods: A study was conducted to investigate the system's strengths and weaknesses by upgrading it with responses from two groups of 15 patients and 4 occupational therapists. After undergoing three forms of training - regarding executive function, memory, and concentration for a total of 20-30 min, the participants were asked to answer a structured questionnaire about contents of the three forms of training, hardware including the tablet PC functioning as a CPU and display media and tangible objects, and satisfaction of experiential usage of the system. Results: Both groups responded that the most interesting training area was executive function while the least interesting was concentration. Six participants reported that the size of the screen of the tablet PC was inappropriate, and five responded that the size of the tool was inappropriate. All therapists and 40% of the patients responded that they were satisfied with this system. Conclusion: This system's features include easy manipulation of tangible tools for performing training tasks, easy selection of and training in cognitive areas based on users' needs, and automatic adjustment of difficulty level based on users' performance. The training environment was designed to be similar to the natural environment by using tangible objects in both hands as input devices for the system, and the system was considered as an alternative to the lack of community cognitive rehabilitation specialists.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.151-171
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• 2023

For the efficient establishment of a channel strategy for banks, this study aims to propose a channel model by classifying channels into types, and carrying out a correspondence analysis per type. A survey of bankers was conducted to visualize categorical data and create a positioning map. As a result, first, 12 banking channels were classified into 4 types based on business processing subjects and places, which were then, further grouped into the categories of full-banking and self-banking. Second, a correspondence analysis according to the classified types was carried out, and it was found that the branch-type is suitable for product description and customer management, while the banking-type is suitable for efficient business processing without time and space constraints. Furthermore, the analysis also showed that the machine-type and banking-type are inappropriate for customer management, and the mobility-type demonstrates low operational effectiveness due to a lack of awareness. The aforementioned findings suggest the need for a hybrid convergence channel that reflects the characteristics of banking tasks and fills in the gaps between the different channels. Third, a channel model was derived by adding a common area to the 2×2 model consisting of the business processing subjects and places. Therefore, this study is meaningful in that it examines the diversification of channels and factors in the division of roles by channel type based on customers' banking channel selection factors, and presents basic research findings for future channel strategy establishment and efficient channel operation.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.79-91
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• 2002

A time variable modeling study was performed for seasonal variations of vertical temperature profiles in the Okjung Lake located in upstream of the Sumjin River. Based on the model structure of the US Army Corps of Engineer's CE-QUAL-W2, the lake was divided into 3 branches, 50 longitudinal segments and 49 vertical layers and vertical profiles of water temperature and current velocity were simulated over one year. The model results were calibrated and verified against vertical profiles of water temperature measured every month from March 1998 to February 1999 at 5 different locations. The model results showed a good agreement with the field measurements. The hydrologic balance during this period was validated by comparing the simulated values of surface elevation level with the measured data. There was some discrepancy in July data between the model results and the fleld measurements. This could be attributed partially to the inadequacy of the model to the highly hydrodynamic nature of water body and partially to the lack of accuracy in local atmospheric temperature data during summer monsoon period. The model results have shown that there was no seasonal over-turn in most part of the Okjung Lake, where water temperature maintained above $4^{\circ}C$ over one year. In the upstream shal-low area (depth<20 meter), however, temperature at surface layer fell below $4^{\circ}C$ and water was frozen such that slight over-turn would occur during winter period. From this study, we concluded that the Okjung Lake is oligomictic. This conclusionis significantly different from the general pattern that the lakes located from $20^{\circ}C$ to $40^{\circ}C$ latitude would be warm monomictic. From the examination of simulated current velocity distribution, it was found that the upstream inflows would infiltrate into mesolimnion of the lake during hydrodynamic summer monsoon periods due to the thermal density of water.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.186-191
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• 2017

The goal of this study was to develop an optimal formula for cookies containing soybean/seoritae, Hwanggum, and isomalto-oligosaccharide using response surface methodology to achieve a blood glucose lowering effect. The model showed a good fit with the experimental data [$R^2=0.92$ (soybean) and 0.93 (seoritae)]. However, the p-value of lack of fit was less than 0.05 and ridge analysis was used to determine an optimal formula. The estimated optimal conditions were as follows: soybean cookie: 68.7% soybean, 2.5% Hwanggum, and 75.2% isomalto-oligosaccharide; seoritae cookie: 56.5% soybean, 3.8% Hwanggum, and 56.2% isomalto-oligosaccharide. The area under the curve and glycemic index were significantly lower in the soybean cookie group than in the control. The glycemic load (GL) index of the soybean (19.9) cookie was in the range of a low-glycemic food (<20 GL). These results can be applied to develop a cookie with a blood glucose lowering effect.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.347-351
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• 2008

Rhizomes of Acorus gramineus Soland have been used as sedatives, analgesics, and stomachics in Korean medicine. Even though A. gramineus produced in Korea is known as having better efficacy of a remedy than that in China, its cultivation area has not increased because of the lack of seedlings. To solve this problem, seed propagation method was tested. Seeds were harvested and sowed three times in June, 2005. The best results showed at greenish yellow seed stage harvested in mid June, and its germination ratio was 90.7%. Seeds were well stored at $5^{\circ}C$ for 30 days. As for in vitro culture, multiple shoots were induced first in MS basal medium supplemented with $2.0mg{\cdot}L^{-1}$ NAA plus $0.1mg{\cdot}L^{-1}$ BA, and then roots were induced in MS basal medium containing $0.1mg{\cdot}L^{-1}$ BA or $0.5mg{\cdot}L^{-1}$ NAA plus $1.0mg{\cdot}L^{-1}$ BA. Growth of A. gramineus seedlings in Wonyesangto, potting material sold in markets for horticultural plants, was superior to vermiculite.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.3
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• pp.321-330
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• 2020

The purpose of this study is to present the appropriate standby space for the mechanical parking lot considered parking queue. This analysis is based on the field-study by results of the influential factors on the parking queue of mechanical parking lots in the commercial area of Gwang-ju metropolitan city. In this study, the parking queue was analized through the simple modeling using Vissim based on average service rate and average arrival rate from the result of field-study. As a result of applying the field survey products to the theoretical queue model, no significant result was obtained when the traffic intensity exceeded 1. Therefore, parking queue was analyzed through simple modeling using Vissim, and the model for calculating the proper parking queue size of the mechanical parking lot by size was derived. The model for estimating of an appropriate mechanical parking standby space considering parking queue presented in this study is expected to be a criterion for considering the appropriate parking space of a new building, and also it can be used to minimized the traffic impact due to the parking queue by the lack of standby space.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.685-695
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• 2012

We studied the detailed bathymetry and the geophysical characteristics of the summit of the Dokdo volcano using mutibeam echosounding and geophysical survey data. The bathymetry around the main east and west islets of the Dokdo volcano shows very shallow within about 10 m water depth. From near islets to about 30 m b.s.l., the shallow water area has very steep slope and many irregular sunken rocks. The area from about 30 m to about 80 m b.s.l. shows gentle rises and falls, and less steep slope. The area from 80 m b.s.l. has gradually flat undulation and smooth slope seabaed and is extended to offshore. The main islets of the Dokdo volcano and the rocky sea bottom elongated from the islets might be the residual part of the eroded and collapsed main crater of the Dokdo volcano. The bathymetry and the seafloor image(from backscattering) data show small craters, assumed to be formed by the eruption of later volcanism. The seafloor images propose that, except some areas with shallow sand sedimentary deposits, there are typical rocky bottom such as rocky protrusions and lack of sediments in the main morphology of the survey area. The stepped slopes of the seabed are deduced to be submarine terraces. The several prominent submarine terraces are found at the summit of the Dokdo volcano, suggesting repetition of sea level changes(transgressions and regressions) in the Quaternary. The results of the magnetic anomaly and the analytic signal have a good coherence with other geophysical consequences regarding to the location of the residual crater.

• Journal of the Korean earth science society
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• v.31 no.3
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• pp.214-224
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• 2010

Gravity and Magnetic survey data were analyzed to investigate the geophysical characteristics and regional geological structures of the southwestern Yellow Sea. The set of data about the southwestern part of the Yellow Sea in Korea was one collected by the Korea Ocean Research and Development Institute (KORDI) in 2003, 2004, and 2005. The Yellow Sea has a few basins and the study area also includes parts of the Heuksan Basin and the East China Sea Basin. The bathymetry of the study area ranges from about ?40 m southwestward near China to about 150 m northeastward near Korea. The bathymetry has the gentle rise and fall and the smooth slope. The gravity anomalies, from sea surface gravity and satellite gravity data, reflect the basement rocks rather than the smooth bathymetry. The gravity anomalies are higher on Northeastern part of the study area and lower over the South of the Heuksan Basin. The analytic signal from the Bouguer anomaly shows higher anomalous zones near the boundaries of the basins. The magnetic anomalies and the analytic signal, from the magnetic data, suggest that the complex anomalies on the Northern part are attributed to the volcanic intrusions and that the smooth patterns in the Southern part are based on the lack of the intrusions. The power spectrum analysis of the Bouguer anomalies and the magnetic anomalies indicate that the depth to the Moho discontinuity varies from about 30.2 to 28.3 km and that the depths of the basement rocks and the Eocene discontinuity range from about 8.4 to 8 km and from about 1.5 to 1.7 km, respectively. The inversion of the Bouguer anomaly shows that the Moho depth to the Western part of the study area near China is slightly deeper than the Eastern part near Korea. The result of 2-D gravity modeling has a good coherence with the results of the analytic signal, the power spectrum analysis, and the inversion.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.2
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• pp.110-126
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• 2024

This study conducted a classification of small-scale biological habitats created in Seoul to analyze and synthesize location characteristics, habitat structure, biological habitat functions, and threat factors of representative sites, as well as derive creation and management problems according to the ecological characteristics. The aim was to suggest improvement measures and management items. Data collected through a field survey was used to categorize 39 locations, and 8 representative sites were selected by dividing them into location, water system, and size as classification criteria for typification. Due to the characteristics of each type, the site was created in an area where amphibian movement was disadvantageous due to low or disconnected connectivity with the hinterland forest, and the water supply was unstable in securing a constant flow and maintaining a constant water depth. The habitat structure has a small area, an artificial habitat structure that is unfavorable for amphibians, having the possibility of sediment inflow, and damage to the revetment area. The biological habitat function is a lack of wetland plants and the distribution of naturalized grasses, and threats include the establishment of hiking trails and decks in the surrounding area. Artificial disturbances occur adjacent to facilities. When creating habitats according to the characteristics of each type, it was necessary to review the possibility of an artificial water supply and introduce a water system with a continuous flow in order to connect the hinterland forest for amphibian movement and locate it in a place where water supply is possible. The habitat structure should be as large as possible, or several small-scale habitats should be connected to create a natural waterfront structure. In addition, additional wetland plants should be introduced to provide shelter for amphibians, and facilities such as walking paths should be installed in areas other than migration routes to prevent artificial disturbances. After construction, the management plan is to maintain various water depths for amphibians to inhabit and spawn, stabilize slopes due to sediment inflow, repair damage to revetments, and remove organic matter deposits to secure natural grasses and open water. Artificial management should be minimized. This study proposed improvement measures to improve the function of biological habitats through the analysis of problems with previously applied techniques, and based on this, in the future, small-scale biological habitat spaces suitable for the urban environment can be created for local governments that want to create small-scale biological habitat spaces, including Seoul City. It is significant in that it can provide management plans.