• The Mathematical Education
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• v.40 no.1
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• pp.77-92
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• 2001

In this study, the number of theses conducted in 1990's for the master's degree in mathematics education was investigated in terms of their fields and themes. These theses were analysed as to how much they had been studied according to the field and whether they had conformed to the expectations and requirements for research in mathematics education under the current educational curriculum. Futhermore, this study aimed to discover advancing directions of research in mathematics education. The results are as follows: First, the rate of annual thesis presentations decreased as many as 3.82% in 1994 compared with the previous year, but the rate increased steadily in the other years showing an overall annual average increase of 8.41%. Second, in the geographical distribution of thesis presentations among local provinces, Seoul represented the highest frequency at 41.13% and Cheju Island the lowest at 1.68%. When the annual thesis presentations were analysed among regions, their number increased steadily in Seoul, but fluctuated in most other regions. Third, regarding study themes, theses on mathematics education formed 70.91% of the total while those focusing on pure mathematics formed 29.09%. Among the theses of mathematics education, most were based on teaching curriculums and the least were based on education assessment. Among the theses on teaching curriculum, teaching analytics formed the highest rate. Theses on education technology, such as computerizing and computing, have shown to be increasing annually and formed 8.95% of the total in 1999. The study also indicated that especially in the late 1990's, there have been many designed programs based on the Web, like JAVA and CGI, and studies on teaching and teaming methods using the internet.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.129-135
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• 2017

The respective delivering vehicle loaded with the own cargo moves into the respective delivery area. At the base, the delivery points D1 and D2, for example, have the same starting point but the destination is different. The average delivering time of the delivery vehicle is mostly more than 8 hours a day. Therefore, the efficiency of delivery is generally low. In this study, the deliveries will be forwarded from a base station to a delivery point where cross docking will be applied to a single vehicle, and will be distributed from the cross docking point through cross docking. If the distribution is implemented, one vehicle will not have to be operated from the base to the cross docking point. In that case, logistics cost will be reasonably saved by the reduction of transportation cost and labor time. If one vehicle only runs from the base to the cross docking point, each vehicle will be operated in two shifts, and the vehicle operation can be efficiently implemented. This research model is based on the assumption that the 3 types of ratios between the traffic volume of the vehicles starting at the base and the vehicles waiting at the cross docking point are set to the first ratio of 30% to 70%, the second ratio of 50% to 50% and the final ratio of 70% to 30%. As a result of the study, The delivery time in the cross docking point is much higher than that in present on the condition that the cargo volume in the D2 area is more than 50%. Likewise, the delivery time is slightly higher on the condition that the cargo volume is less than 50%. Time is reduced in terms of 50% model like AS-IS model.

• Journal of Environmental Science International
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• v.13 no.12
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• pp.1023-1032
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• 2004

Rapid progress in urbanization has resulted in a change of the micro climate, especially in the urban area. In order to investigate the phenomenon of the heat island in the residential micro climate, a field survey was carried out by 4 sets of the residential type in Jeonju under typical winter synoptic condition. As analytic methode, it is used the comparison on the relation of the Land-to-Coverage Rate to Heat Island and Oxygen Concentration. And as a key question it is asked how stable characteristics of the micro climate will result from the survey of the Heat Island and the Oxygen Concentration, used as indicator. To ensure the trustworthy result of research, it is calculated the critical influence of the wind velocity and the Land-to-Covearage Rate. As a result of comparative analysis, it could be confirmed that the local temperatures in all sets of the residential type were higher than the average temperature in Jeonju. But the housing type A 'exclusive use for housing zone' has relativly the most stable and best living condition. On the contrary the residential type B and D has the worst toward the oxygen concentration in the time zone 9-12 a.m., which didn't reach the minimum of the oxygen concentration $20.5{\%}.$ It means that the higer the development and population density is, the worse is the situation of the Quality of Life in the residential types in accordance with the heat island and oxygon con­centration.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.101-112
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• 2013

Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) offers opportunities to make advances in many research areas including hydrology by providing near-global scale elevation measurements at a uniform resolution. Its wide coverage and complimentary online access especially benefits researchers requiring topographic information of hard-to-access areas. However, SRTM DEM also contains inherent errors, which are subject to propagation with its manipulation into analysis outputs. Sensitivity of hydrologic analysis to the errors has not been fully understood yet. This study investigated their impact on estimation of hydrologic derivatives such as slope, stream network, and watershed boundary using Monte Carlo simulation and spatial moving average techniques. Different amount of the errors and their spatial auto-correlation structure were considered in the study. Two sub-watersheds of Geum and Deadong River areas located in South and North Korea, respectively, were selected as the study areas. The results demonstrated that the spatial presentations of stream networks and watershed boundaries and their length and area estimations could be greatly affected by the SRTM DEM errors, in particular relatively flat areas. In the Deadong River area, artifacts of the SRTM DEM created sinks even after the filling process and then closed drainage basin and short stream lines, which are not the case in the reality. These findings provided an evidence that SRTM DEM alone may not enough to accurately figure out the hydrologic feature of a watershed, suggesting need of local knowledge and complementary data.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.1 s.47
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• pp.33-39
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• 2006

Parameters including the seismic sources and the elastic wave propagation characteristics were analysed using the observed ground motions from 3 Kyoungju region earthquakes. The Levenberg-Marquardt algorithm was applied to invert all the variables non-linearly and simultaneously with S wave energy In frequency domain. Average stress drop of 3 events and local attenuation parameter ${\kappa}$ were estimated to about 48-bar and 0.0312 respectively. Regional attenuation parameter, Qo and ${\eta}$, were also estimated to be about 417 and 0.83. ${\kappa}$ values are much higher than that of EUS, even though smaller than that of WUS. All these values resultant from this study show that there are differences in some parameters of other studios due to differences in the governing equation. of acceleration motions

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.32.2-32.2
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• 2013

We examine large-scale environmental effects on the formation and the mass growth of dark matter halos. To facilitate this, we constructed dark matter halo merger trees from a cosmological N-body simulation, which enabled us to trace the merger information and the assembly history of individual halos. In fact, since the massive halos are more likely to be distributed in denser regions than in less dense regions (Mo & White, 1996), the large-scale environment dependence of the properties of halos can be partly originated from the halo mass effect. In order to avoid such contamination, caused by the mass dependence of halo properties, we carefully measured the local overdensity as the indicator of large-scale environment, which was calculated to be as independent of halo mass as possible. Small halos (${\sim}10^{11-12}M_{\odot}$), which usually host isolated single galaxies, show a notable difference on the formation time of galaxies depending on their large-scale environments, which reconfirms halo assembly bias (Gao & White, 2007). Furthermore, we investigate how this environmental effect on small halos is correlated with the mass assembly history of galaxies by using our semi-analytic model. We found that assembly bias in small halos does not have significant effects on the formation time or on the star formation history of galaxies residing in those halos except for the individual stellar mass of galaxies at z = 0. On average, isolated galaxies in high-density regions tend to be slightly more massive than those in low-density regions. Although the observational data from the current galaxy surveys is not yet sufficient for testing this prediction, future galaxy surveys will be able to explore these small galaxies more thoroughly.

• Journal of Korean Public Health Nursing
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• v.19 no.2
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• pp.229-240
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• 2005

Purpose: To evaluate every step of the cancer screening program. Method: 146 of 233 health centers participated in this study. Data were collected by mailing questionnaires between December 2002 and January 2003. The response rate was 65.5%. Result: The government cancer screening program was directed by a variety of departments of the health centers. 41.1% of persons in charges were nurses. 41.3% of the health centers received a list of the appropriate person from the National Health Insurance Cooperation within one or two months. 26.1% of health centers received ??? after five month from when the program started. All the health centers advertised their services, and most of them used mail and mass media 56.4%, used other institute's materials, and 72.2% of them used the government's materials. 76.7% of the heath centers recommended secondary health screening to the persons who had positive results at the first screening. 71.6% of the health centers ascertained the patients with cancer who were diagnosed at secondary screenings. 67.9% of the health centers had registered home-based cancer patients at the health center. 137 out of 146 health centers had a local institute for cancer screening; an average of 4.9 institutes had cancer screening. 80.1% of the persons in charge of the programs felt they needed this program, but 80.8% of them thought the program should be modified. Conclusion: Organized and standardized programs are needed to promote the efficiency of National Cancer Screening Program.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1259-1269
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• 2015

Recently, big data is positioning as a keyword in the academic circles. And usefulness of big data is carried into government, a local public body and enterprise as well as academic circles. Also they are endeavoring to obtain useful information in big data. This research mainly deals with analyses of box office success or failure of films using text mining. For data, it used a portal site 'D' and film review data, grade point average and the number of screens gained from the Korean Film Commission. The purpose of this paper is to propose a model to predict whether a film is success or not using these data. As a result of analysis, the correct classification rate by the prediction model method proposed in this paper is obtained 95.74%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.6
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• pp.665-680
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• 1997

The specific absorption rate (SAR) distributions in various models of the human head have been analyzed when the models are exposed to 350 MHz and 900 MHz plane waves. The numerical analysis is performed with the finite-difference time-domain (FDTD) method. A homogeneous sphere including a cylinderical neck, a homogeneous head shaped model, and a heterogeneous realistic model are used as models of human head. The incident plane wave used for these calculations is propagating from the front to the back or from the back to the front of the head model, with its E-field vector orientation being parallel to the major length of the body. The specific findings are: 1) the average SARs of the three models are similar mutually but the local SARs of them differ greatly mutually; 2) the power is deposed more deeply in the head at 350 MHz, which is roughly the resonant frequency of a human head, than at 900 MHz; 3) for a plane wave propagating from the back, "hot spot" is found in the neck region, not in the head; 4) for a plane wave propagating from the front, "hot spot" is found in the nose at 900 MHz, and in the upper part of the lip and the jaw region at 350 MHz.

• Journal of Periodontal and Implant Science
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• v.28 no.2
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• pp.193-203
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• 1998

20 Subjects with clinical diagnosis of adult periodontitis with sites having average pocket depth of 4mm were selected for the study. After scaling and root planing of those sites, 30% minocycline-HCI contained in biodegradable device were inserted in one group, scaling and root planing was carried out in another group and the last group was without any periodontal treatment. the difference between the group was detemined by pocket dept, bleeding on prbing, attachment level, distribution of subgingval plaque bacteria. Conclusion was made for the comparisons between baseline and 4 week and the groups. 1. In analysis of pocket depth, there was significant sifference in scaling and root planing group only. 2. Both the scaling and root planing group and minocycline group showed significant decrease in bleeding on probing. 3. There was significant increase in the attachment level in scaling and root planing group, but no difference was foundbetween the groups. 4. There was significant decrease in the total number of subgingival bacteria in all groups and the number of motile bacteria decreased significantly in the minocycline group. These result indicate that insertion of Minocycline-HCI at the base of periodntal pocket was useful as an additional aid of mechanical trarment at the point of periodontal pocket, bleeding on probing, attachment level, microbial distribution.