• Proceedings of the KSR Conference
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• 2007.11a
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• pp.551-557
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• 2007

This paper describes a study on the permeability reduction of the riverbed ground during urban railway tunnel construction. The research is mainly concentrated on the study of the grouting or injection methods among permeability reduction methods which can be adapted in the riverbed ground. Firstly, the various grouting methods are theoretically reviewed and compared based on the previous research papers and case study results. It is also evaluated the grouting methods in view of a safe construction of the river crossing railway tunnel. Baced on the literature review and previous construction data, the design technology of grouting methods considering the long term hydro-geological behaviour in the riverbed, is suggested. Two injection methods namely, Natural Durable Stabilizer(N.D.S) and Space-Multi Injaction Grouting(S.M.I) methods, are introduced as new approach methods which can be adopted to modify the riverbed ground. In order to evaluate the ground that grouted and modified by the N.D.S and S.M.I method, the pilot test programmes including the field and laboratory permeability tests, are carried out in the river crossing tunnel construction sites. The results obtained from pilot test programme, are also reviewed. In conclusion, the grouting efficiency of the S.M.I method using the non-alcalimeter silica sol is better than that of NDS method using cement. In addition, it hopes that the research results are contributed to develop the grouting design technology.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.753-767
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• 2009

Objectives : The study is to gain some basic material for the improvement of dental clinics' homepages through a survey investigation, in which college students of three Dental Hygienic departments participated in Kwangju and Cheollanamdo Province. Methods : In the investigation three factors were analyzed : the degree of knowledge on dental clinics' homepages, the degree of recognition on them, and whether they have paid a visit on them or not. A total of 509(96.8%) respondents are valid except 17sheets of responses. Results : 1. When asked about the degrees of knowledge on the formation of the homepages by students' years, the correct rate on Information Service was higher in a row of the second year, the first year, and the third year. And it shows statistically significant difference(p<0.05). In the part of Counseling Service, the rate of correct answers was highest in the second year, and then the first year and the third year. It also shows significant difference(p<0.05). In case of Visual Service, the second year got the highest rate of correct answers, and then the first year and the third year. Here is significant difference by the school years<0.01) 2. It was asked whether they have visited the dental clinics' homepages. The results are like this: 145 sophomores(28.5%) have visited them, and 115 juniors(22.6%) and 85 freshmen(16.7%), and it show significant difference (p<0.001). 3. It was asked how many sites they have visited. Among the freshmen, not a few students visited two sites (34, 9.9%), among sophomores 48 students visited five sites(13.9%), and among juniors the highest answers were two sites (41, 11.9%). It shows signigicant difference(p<0.01). 4. It was asked what is the purpose of the visits. At this 27 freshmen answered for having counseling(7.8%), and 80 sophomores(23.3%) and 43 juniors(12.5%) answered they visited them for the purpose of gaining some materials about their major. It shows significant difference(p<0.001). 5. It was asked with what opportunity they have visited them. They answered through searching activities like this : freshmen (68, 19.8%), sophomores (130, 37.9%), and juniors (98, 28.6%). It shows significant difference(p<0.05). 6. In regard with the recognition of the homepages, all the participants said that the management of the homepages are closely related with the images of the clinics($3.96{\pm}0.781$). But it is found that they do not think that the effective management of dental clinics' homepages is the task of dental hygienic workers as a part of dental hygienic($3.12{\pm}0.971$). 7. There is some difference concerned with the homepages among each group of students; sophomores have highest recognition on them and then juniors and freshmen, and it shows significant difference(p<0.01). In addition, those who have visited them show higher recognition than those who have never visited them(p<0.001). Conclusions : There are some differences among each group of students in regard with the formation service, the purpose of visiting them and such experiences, and the opportunities. Whereases they think that the management of the homepages are closely related with the images of the clinics, they do not think that the effective management of dental clinics' homepages is the task of dental hygienic workers as a part of dental hygienic. Therefore it is necessary to study actively for the qualitative improvement of the dental clinics' homepages, which will result in the higher recognition on the homepages by the dental hygienic students and the workers.

• Journal of Science Education
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• v.42 no.1
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• pp.27-48
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• 2018

The purposes of this study are to derive suggestions and implications to improve the continuity of Korean Science & Practical Arts (Technology Home Economics) curricula through international comparative analysis with focus on the science curricula or standards in five countries (Canada, New Zealand, Singapore, the United States, Korea). Original documents of the national curriculums or standards of each country collected from NCIC comparatively analyzed the big concepts of the 'system' and 'energy' based on features of related components of curriculum contents, vertical, and lateral connectivity. The results indicated that the big concepts of systems and energy were used internationally to consider the curriculum continuity. In most countries, the big concept of system was used as a framework to integrate science with technology or other contents. In particular, it was also utilized to strengthen vertical and lateral connectivity in earth science and space science contents area. In the comparison of countries for the system as the big concept, New Zealand focused interrelationship between system and human activities, systems' interaction, levels and features of system concept for the linkage between grades and subjects on the basis of level. In the case of Canada and Singapore, science and technology are combined to strengthen contents' connection. However, the revised 2015 curriculum has a lack of continuity and sequence because the concepts of system and energy were concentrated on a specific grade and contents' area. The curriculum was not developed systematically for multiple grades according to their levels. In conclusion, Korean science curriculum requires sufficient understanding of students' learning and research on learning progressions and curriculum continuity. In addition, it is very important to constitute the curriculum based on the vertical and lateral connectivity in order to improve science education and to foster students' key competencies and abilities.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.47-60
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• 2010

Most of the researches about classification usually have used kNN(k-Nearest Neighbor), SVM(Support Vector Machine), which are known as learn-based model, and Bayesian classifier, NNA(Neural Network Algorithm), which are known as statistics-based methods. However, there are some limitations of space and time when classifying so many web pages in recent internet. Moreover, most studies of classification are using uni-gram feature representation which is not good to represent real meaning of words. In case of Korean web page classification, there are some problems because of korean words property that the words have multiple meanings(polysemy). For these reasons, LSA(Latent Semantic Analysis) is proposed to classify well in these environment(large data set and words' polysemy). LSA uses SVD(Singular Value Decomposition) which decomposes the original term-document matrix to three different matrices and reduces their dimension. From this SVD's work, it is possible to create new low-level semantic space for representing vectors, which can make classification efficient and analyze latent meaning of words or document(or web pages). Although LSA is good at classification, it has some drawbacks in classification. As SVD reduces dimensions of matrix and creates new semantic space, it doesn't consider which dimensions discriminate vectors well but it does consider which dimensions represent vectors well. It is a reason why LSA doesn't improve performance of classification as expectation. In this paper, we propose new LSA which selects optimal dimensions to discriminate and represent vectors well as minimizing drawbacks and improving performance. This method that we propose shows better and more stable performance than other LSAs' in low-dimension space. In addition, we derive more improvement in classification as creating and selecting features by reducing stopwords and weighting specific values to them statistically.

• Journal of radiological science and technology
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• v.32 no.4
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• pp.361-370
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• 2009

The image quality management of bone mineral density is the responsibility and duty of radiologists who carry out examinations. However, inaccurate conclusions due to lack of understanding and ignorance regarding the methodology of image quality management can be a fatal error to the patient. Therefore, objective of this paper is to understand proper image quality management and enumerate methods for examiners and patients, thereby ensuring the reliability of bone mineral density exams. The accuracy and precision of bone mineral density measurements must be at the highest level so that actual biological changes can be detected with even slight changes in bone mineral density. Accuracy and precision should be continuously preserved for image quality of machines. Those factors will contribute to ensure the reliability in bone mineral density exams. Proper equipment management or control methods are set with correcting equipment each morning and after image quality management, a phantom, recommended from the manufacturer, is used for ten to twenty-five measurements in search of a mean value with a permissible range of ${\pm}1.5%$ set as standard. There needs to be daily measurement inspections on the phantom or at least inspections three times a week in order to confirm the existence or nonexistence of changes in values in actual bone mineral density. in addition, bone mineral density measurements were evaluated and recorded following the rules of Shewhart control chart. This type of management has to be conducted for the installation and movement of equipment. For the management methods of inspectors, evaluation of the measurement precision was conducted by testing the reproducibility of the exact same figures without any real biological changes occurring during reinspection. Bone mineral density inspection was applied as the measurement method for patients either taking two measurements thirty times or three measurements fifteen times. An important point when taking measurements was after a measurement whether it was the second or third examination, it was required to descend from the table and then reascend. With a 95% confidence level, the precision error produced from the measurement bone mineral figures came to 2.77 times the minimum of the biological bone mineral density change. The value produced can be stated as the least significant change (LSC) and in the case the value is greater, it can be stated as a section of genuine biological change. From the initial inspection to equipment moving and shifter, management must be carried out and continued in order to achieve the effects. The enforcement of proper quality control of radiologists performing bone mineral density inspections which brings about the durability extensions of equipment and accurate results of calculations will help the assurance of reliable inspections.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.529-533
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• 2015

VCUG(Voiding Cystourethrography) study is being performed to check urinary reflex symptom from bladder to ureter or kidney in the method of filling the bladder with radiation opaque contrast agent. However, VCUG study have been performed impersonally, patients have to be naked and open their legs and then void. This method is so impersonal that it is immediately needed to improve the way of testing and crete new aid. Therefore, this study through producing underwear for VCUG, analysis and compares the test time of VCUG, patient radiation dose and patient satisfaction. The target of this study was 79 Male and Female patients who visited genitourinary clinic of PNUYH for their VCUG tests AXIUM Iconos R200(Siemens Medical System : Germany) and self-produced plastic underwears made by vinyl and plasic molding machine were used. The 79 patient were divided into two groups : experiment of patient and comparison group of we patient (using aid) in order to compare, testing time, DAP (dose area product) and patient satisfaction. There was time reduction, from 35.3min of comparison group to 27.8min experimentation group by 7.5min decrease. And comparison group of $4566.6{\mu}Gym^2$(DAP) decreased experimental group (using aid) of $3411.9{\mu}Gym^2$ by $1154.7{\mu}Gym^2$. In the case of patients satisfaction study, anxiety had a drop by 3.45 of comparison group to 2.51 experimentation group by 0.94 decrease. in experimental group. And shame had a drop by 4.02 of comparison group to 3.08 experimentation group by 0.94 increase. in experimental group. Difference of the smooth voiding had a drop by 1.90 of comparison group to 2.84 experimentation group by 0.94 increase. in experimental group. In addition satisfaction had a rise by 1.19 in experimental group. There were also other opinions of uncomfortableness on it and troublesome to wear. VCUG is one of the sensitive care required test. Therefore staff and the aid can give patients such comfortable and the aid can consentive on voiding. As a result test time and DAP can be reduced. It is needed to make testing at more comfortable for patients.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.773-780
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• 2020

With the development of the 4th industrial, research is being conducted to prevent diseases and reduce damage in various fields of science and technology such as medicine, health, and bio. As a result, artificial intelligence technology has been introduced and researched for image analysis of radiological examinations. In this paper, we will directly apply a deep learning model for classification and detection of pneumonia using chest X-ray images, and evaluate whether the deep learning model of the Inception series is a useful model for detecting pneumonia. As the experimental material, a chest X-ray image data set provided and shared free of charge by Kaggle was used, and out of the total 3,470 chest X-ray image data, it was classified into 1,870 training data sets, 1,100 validation data sets, and 500 test data sets. I did. As a result of the experiment, the result of metric evaluation of the Inception V3 deep learning model was 94.80% for accuracy, 97.24% for precision, 94.00% for recall, and 95.59 for F1 score. In addition, the accuracy of the final epoch for Inception V3 deep learning modeling was 94.91% for learning modeling and 89.68% for verification modeling for pneumonia detection and classification of chest X-ray images. For the evaluation of the loss function value, the learning modeling was 1.127% and the validation modeling was 4.603%. As a result, it was evaluated that the Inception V3 deep learning model is a very excellent deep learning model in extracting and classifying features of chest image data, and its learning state is also very good. As a result of matrix accuracy evaluation for test modeling, the accuracy of 96% for normal chest X-ray image data and 97% for pneumonia chest X-ray image data was proven. The deep learning model of the Inception series is considered to be a useful deep learning model for classification of chest diseases, and it is expected that it can also play an auxiliary role of human resources, so it is considered that it will be a solution to the problem of insufficient medical personnel. In the future, this study is expected to be presented as basic data for similar studies in the case of similar studies on the diagnosis of pneumonia using deep learning.

• Pediatric Infection and Vaccine
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• v.10 no.2
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• pp.159-166
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• 2003

Purpose : Streptococcus pneumoniae is part of the normal flora but is also responsible for causing many invasive diseases such as pneumonia, meningitis, and sepsis in addition to noninvasive diseases such as otitis in children. Multi-drug resistant strains has raised a lot of concern worldwide and thus the importance of prevention has been emphasized. We have analyzed the current serotypes and antibiotic sensitivity of each serotype as a baseline study to estimate the efficacy of the pneumococcal vaccine in Korean children. Methods : One hundred sixteen cases of pneumococcus cultured at Yonsei Medical Center from September 2001 to January 2003 were analyzed. The serotyping was done with the Quellung reaction and penicillin resistance was tested using the oxacillin disc diffusion method. Results : Pneumococcus were cultured from the sputum in 76 cases(65.5%), from the blood in 13 cases(11.2%), from the ear discharge in 12 cases(10.3%), from the throat in 7 cases(6.0%), from the nasal cavity in 2 cases(1.7%), and one case(0.9%) each from the cerebrospinal fluid, eye discharge, peritoneal fluid, post-operational wound, brain abscess, and catheter tip. Serotyping was possible with 98 cases and the following serotypes were found; 15 cases of type 19F(15.3%), 11 cases of 19A(11.2%), 8 cases of 11A(8.2%), 7 cases each of 6A, 14 and 3(7.1%), 6 cases each of 35, 6B and 23F(6.1%). Eighty two cases(70.7%) out of 116 cases were penicillin resistant and serotypes 19F, 19A, 11A, 23F, 6A, 9V constituted the majority, 48 cases(59.8%). These serotypes showed resistance to cotrimoxazole (74.4%), tetracycline(69.5%), and erythromycin(90.3%) as well. In the 22 cases cultured from children, 19A and 19F were found in 25.0%, 6A, 6B, and 23F in 10.0%, 11A, 14, 19, and 29 in 5.0%. Fifty percent(10/20) of the clinical isolates were represented in the current 7-valent pneumococcal protein conjugate vaccine, and 85%(17/20) when the cross-reacting serotypes were included. Penicillin resistance was found in 86.4%(19/22). Conclusion : The percentage of serotypes included in the 7 valent pneumococcal protein conjugate vaccine found in our study was 40.8% which was less than other prior studies. In anticipation of a change of pneumococcal serotypes, a nationwide multicenter study is needed before the initiation of pneumococcal vaccines in Korea.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.172-179
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• 2016

Purpose: Bacillus cereus has been reported as the cause of nosocomial infections in cancer patients. In our pediatric cancer ward, a sudden rise in the number of patients with B. cereus bacteremia was observed in 2013 to 2014. This study was performed to investigate the molecular epidemiology of increased B. cereus bacteremia cases in our center. Methods: Pediatric cancer patients who developed B. cereus bacteremia were identified from January 2001 to June 2014. The B. cereus bacteremia in this study was defined as a case in which at least one B. cereus identified in blood cultures, regardless of true bacteremia. Available isolates were further tested by multilocus sequence typing (MLST) analysis. A retrospective chart review was performed. Results: Nineteen patients developed B. cereus bacteremia during the study period. However, in 2013, a sudden increase in the number of patients with B. cereus bacteremia was observed. In addition, three patients developed B. cereus bacteremia within 1 week in July and the other three patients within 1 week in October, respectively, during emergency room renovation. However, MLST analysis revealed different sequence types without consistent patterns. Before 2013, five tested isolates were ST18, ST26, ST177, and ST147-like type, and ST219-like type. Isolates from 2013 were ST18, ST73, ST90, ST427, ST784, ST34-like type, and ST130-like type. Conclusions: MLST analyses showed variable ST distribution of B. cereus isolates. Based on this study, there was no significant evidence suggesting a true outbreak caused by a single ST among patients who developed B. cereus bacteremia.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.351-363
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• 2020

It is well known that alluvial sediment located in coastal region has been easily affected by geohazard like ground subsidence, marine or meteorological disasters which threaten invaluable lives and properties. The subsidence is a sinking of the ground due to underground material movement that mostly related to soil compaction by water extraction. Thus, continuous monitoring is essential to protect possible damage from the ground subsidence in the coastal region. Radar interferometric application has been widely used to estimate surface displacement from phase information of synthetic aperture radar (SAR). Thanks to advanced SAR technique like the Small BAseline Subset (SBAS), a time-series of surface displacement could be successfully calculated with a large amount of SAR observations (>20). Because the ALOS-2 PALSAR-2 L-band observations maintain higher coherence compared with other shorter wavelength like X- or C-band, it has been regarded as one of the best resources for Earth science. However, the number of ALOS-2 PALSAR-2 observations might be not enough for the SBAS application due to its global monitoring observation scenario. Unfortunately, the number of the ALOS-2 PALSAR-2 Stripmap images in area of our interest, Busan which located in the Southeastern Korea, is only 11 which is insufficient to apply the SBAS time-series analysis. Although it is common that the radar interferometry utilizes multiple SAR images collected from same acquisition mode, it has been reported that the ALOS-2 PALSAR-2 Stripmap-ScanSAR interferometric application could be possible under specific acquisition mode. In case that we can apply the Stripmap-ScanSAR interferometry with the other 18 ScanSAR observations over Busan, an enhanced time-series surface displacement with better temporal resolution could be estimated. In this study, we evaluated feasibility of the ALOS-2 PALSAR-2 Stripmap-ScanSAR interferometric application using Gamma software considering differences of chirp bandwidth and pulse repetition frequency (PRF) between two acquisition modes. In addition, we analyzed the interferograms with respect to spectral shift of radar carrier frequency and common band filtering. Even though it shows similar level of coherence regardless of spectral shift in the radar carrier frequency, we found periodic spectral noises in azimuth direction and significant degradation of coherence in azimuth direction after common band filtering. Therefore, the characteristics of spectral bandwidth in the range and azimuth direction should be considered cautiously for the ALOS-2 PALSAR-2 Stripmap-ScanSAR interferometry.