• Communications of Mathematical Education
• /
• v.21 no.2 s.30
• /
• pp.153-176
• /
• 2007

The purpose of this paper is to analyze teaching-learning program which can be applied to mathematically gifted students in primary school, Our program is based on constructivist views on teaching and learning of mathematics. Mainly, we study the algorithmic thinking of mathematically gifted students in primary school in connection with the network problems; Eulerian graph problem, the minimum connector problem, and the shortest path problem, The above 3-subjects are not familiar with primary school mathematics, so that we adapt teaching-learning model based on the social constructivism. To achieve the purpose of this study, seventeen students in primary school participated in the study, and video type(observation) and student's mathematical note were used for collecting data while the students studied. The results of our study were summarized as follows: First, network problems based on teaching-learning model of constructivist views help students learn the algorithmic thinking. Second, the teaching-learning model based on constructivist views gives an opportunity of various mathematical thinking experience. Finally, the teaching-learning model based on constructivist views needs more the ability of teacher's research and the time of teaching for students than an ordinary teaching-learning model.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.4
• /
• pp.721-726
• /
• 2012

In this paper, we proposed an efficient algorithm based on SPFA(shortest path faster algorithm), which is an improved the Bellman-Ford algorithm. The Bellman-Ford algorithm can be used on graphs with negative edge weights unlike Dijkstra's algorithm. And SPFA algorithm used a queue to store the nodes, to avoid redundancy, though the Bellman-Ford algorithm takes a long time to update the nodes table. In this improved algorithm, an adjacency list is also used to store each vertex of the graph, applying dynamic optimal approach. And a queue is used to store the data. The improved algorithm can find the optimal path by continuous relaxation operation to the new node. Simulations to compare the efficiencies for Dijkstra's algorithm, SPFA algorithm and improved Bellman-Ford were taken. The result shows that Dijkstra's algorithm, SPFA algorithm have almost same efficiency on the random graphs, the improved algorithm, although the improved algorithm is not desirable, on grid maps the proposed algorithm is very efficient. The proposed algorithm has reduced two-third times processing time than SPFA algorithm.

• Journal of Digital Convergence
• /
• v.13 no.12
• /
• pp.161-169
• /
• 2015

Realtime search words of typical portal sites appear every few seconds in descending order by search frequency in order to show issues increasing rapidly in interest. However, the characteristics of realtime search words reordering within too short a time cause problems that they go over the key issues of the day. This paper proposes a method for deriving a key issue through association analysis of realtime search words. The proposed method first makes scores of realtime search words depending on the ranking and the relative interest, and derives the top 10 search words through descriptive statistics for groups. Then, it extracts association rules depending on 'support' and 'confidence', and chooses the key issue based on the results as a graph visualizing them. The results of experiments show that the key issue through association rules is more meaningful than the first realtime search word.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.6
• /
• pp.1099-1107
• /
• 2019

Objectives: The purpose of this study was to investigate the changes in pH in the oral cavity using the probiotic intake method. Methods: A total of 109 participants were enrolled and randomly assigned to three groups. Participants in the control group did not ingest powdered probiotics, those in experimental group 1 ingested powdered probiotics by dissolving them on the tongue, and those in experimental group 2 dissolved powdered probiotics on the tongue and rinsed with water. pH values were measured 5 times in all. The significance of each group was examined by the Kruskal-Wallis test. The trend over time was expressed as a graph with groupwise means and confidence intervals, considering repeated measurement data. Results: A significant difference was found between the control group and experimental group 1 at two time-points, i.e., immediately after intake and 3 min after ingestion. As a result of the time trend, the pH value of experimental group 2 was smaller than that of experimental group 1, compared to the control group. Conclusions: Studies have shown that taking probiotics with water may help reduce changes in oral pH. Probiotics should be aware of live bacteria and provide consumers with more detailed information on proper dosage and precautions.

• Journal of Internet Computing and Services
• /
• v.8 no.5
• /
• pp.1-10
• /
• 2007

Recently, the web 2.0 services which appear by exponential extension of the Internet can be expressed with the changes in the quality of structural evolution and in the quantity of increasing users. The structural base is in user participational architecture, the web 2.0 services such as Blog, UCC, SNS(Social Networking Service), Mash-up, Long tail, etc. play a important role in organization of web, and grouping and searching of user participational data in web 2.0 is broadly used by folksonomy. Folksonomy is a new form that categorizes by tags, not classic taxonomy skill. it is made by user participation. Searching based on tag is now done by a simple text or a tag cloud method. But searching to consider and express the relations among each tags is imperfect yet. Thus, this paper provides the relational searching based on tags using the relational graph of tags. It should improve the trust of the searching and provide the convenience of the searching.

• The Mathematical Education
• /
• v.56 no.3
• /
• pp.281-300
• /
• 2017

This study analyzed the difficulties of middle school students in computer simulation of the law of large numbers through eye movement analysis. Some students did not attend to the simulation results and could not make meaningful inferences. It is observed that students keep the existing concept even though they observe the simulation results which are inconsistent with the misconceptions they have. Since probabilistic intuition influence student's thinking very strongly, it is necessary to design a task that allows students to clearly recognize the difference between their erroneous intuitions and simulation results. In addition, we could confirm through eye movements analysis that students could not make meaningful observations and inferences if too much reasoning was needed even though the simulation included a rich context. It is necessary to use visual representations such as graphs to provide immediate feedback to students, to encourage students to attend to the results in a certain intentional way to discover the underlying mathematical structure rather than simply presenting experimental data. Some students focused their attention on the visually salient feature of the experimental results and have made incorrect conclusion. The simulation should be designed so that the patterns of the experimental results that the student must discover are not visually distorted and allow the students to perform a sufficient number of simulations. Based on the results of this study, we suggested that cumulative relative frequency graph showing multiple results at the same time, and the term 'generally tends to get closer' should be used in learning of the law of large numbers. In addition, it was confirmed that eye-tracking method is a useful tool for analyzing interaction in technology-based probabilistic learning.

• Journal of Animal Science and Technology
• /
• v.59 no.5
• /
• pp.12.1-12.7
• /
• 2017

Background: Despite the widespread use of dexamethasone in veterinary and human medicine, it is reported to cause some severe pregnancy related side effects like abortion in some animals. The mechanism of the response is not clear but seems to be related to interspecies and/or breed difference in response which may involve alterations in the concentrations of some reproductive hormones. Methods: Twenty Sahel goats comprising 18 does and 2 bucks were used for this study. Pregnancies were achieved by natural mating after synchronization. Repeated dexamethasone injections were given at 0.25 mg/kg body weight. Blood samples were collected biweekly for hormonal assay. Uterine biopsies were harvested at days 28 and day 78 of gestation through caesarean section for immunohistochemical analysis using 3 pregnant does randomly selected from each group at each instant. Data were expressed as Means ${\pm}$ Standard Deviations and analyzed using statistical soft ware package, GraphPad Instant, version 3.0 (2003) and progesterone receptor (PR) were scored semi-quantitatively. Results: Dexamethasone treatments had no significant (p > 0.05) effect on progesterone and estrogen concentrations in pregnant Sahel goats but up regulated PR from 2+ to 3+ in second trimester. Conclusion: As dexamethasone adverse effect on placenta is an established fact, the lack of effect on progesterone level in this study may be due to the fact that unlike other species whose progesterone production during pregnancy is placenta - dependent, in goats is corpus luteum - dependent. Consequently dexamethasone adverse effect on placenta reported in literatures did not influence progesterone levels during pregnancy in Sahel goat. The up regulation of progesterone receptor (PR) in Sahel goat gravid uterus is a beneficial effects and that dexamethasone can safely be used in corpus luteum - dependent progesterone secreting pregnant animal species like Sahel goat and camel. Therefore source of progesterone secretions during pregnancy should be considered in clinical application of dexamethasone in pregnancy.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.29 no.1
• /
• pp.71-80
• /
• 2011

Thresholding is important step for detecting binary change/non-change information in the unsupervised change detection. This study proposes new unsupervised change detection method using Hyperion hyperspectral images, which are expected with data increased demand. A graph is drawn with applying the range average method for the result value through pixel-based similarity measurement, and thresholding value is decided at the maximum distance point from a straight line. The proposed method is assessed in comparison with expectation-maximization algorithm, coner method, Otsu's method using synthetic images and Hyperion hyperspectral images. Throughout the results, we validated that the proposed method can be applied simply and had similar or better performance than the other methods.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.516-516
• /
• 2002

With the wide usage of LiDAR data and high-resolution satellite image, 3D modeling of buildings in urban areas has become an important research topic in the photogrammetry and computer vision field for many years. However the previous modeling has its limitations of merely texturing the image to the DSM surface of the study area and does not represent the relief of building surfaces. This study is focused on presenting a system of realistic 3D building modeling from consecutive stereo image sequences using digital camera. Generally when acquiring images through camera, various parameters such as zooming, focus, and attitude are necessary to extract accurate results, which in certain cases, some parameters have to be rectified. It is, however, not always possible or practical to precisely estimate or rectify the information of camera positions or attitudes. In this research, we constructed the collinearity condition of stereo images through extracting the distinctive points from stereo image sequence. In addition, we executed image matching with Graph Cut method, which has a very high accuracy. This system successfully performed the realistic modeling of building with a good visual quality. From the study, we concluded that 3D building modeling of city area could be acquired more realistically.

• Journal of Chest Surgery
• /
• v.48 no.2
• /
• pp.105-111
• /
• 2015

Background: The aim of this study was to establish whether pulmonary lobectomy using video-assisted thoracic surgery (VATS) can be safely performed by trainees with limited experience with open lobectomy. Methods: Data were retrospectively collected from 251 patients who underwent VATS lobectomy at a single institution between October 2007 and April 2011. The surgical outcomes of the procedures that were performed by three trainee surgeons were compared to the outcomes of procedures performed by a surgeon who had performed more than 150 VATS lobectomies. The cumulative failure graph of each trainee was used for quality assessment and learning curve analysis. Results: The surgery time, estimated blood loss, final pathologic stage, thoracotomy conversion rate, chest tube duration, duration of hospital stay, complication rate, and mortality rate were comparable between the expert surgeon and each trainee. Cumulative failure graphs showed that the performance of each trainee was acceptable and that all trainees reached proficiency in performing VATS lobectomy after 40 cases. Conclusion: This study shows that trainees with limited experience with open lobectomy can safely learn to perform VATS lobectomy for the treatment of lung cancer under expert supervision without compromising outcomes.