• The Journal of Korean Orthopaedic Ultrasound Society
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• v.6 no.1
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• pp.1-9
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• 2013

Purpose: The purpose is to perform objective evaluation for rotator cuff using ultrasonography and validate factors influencing cuff integrity as well as efficacy of follow-up ultrasonography after unreamed antegrade intramedullary nailing for humerus fracture. Materials and Methods: Seventeen patients with an average age of $55.7{\pm}18.6$ years underwent antegrade intramedullary nailing for humerus fracture and follow-up ultrasonography of shoulder joint. Mean follow-up period was $43.5{\pm}32.2$ months. Intraoperative evaluation for preoperative cuff tear was performed, of which four cuffs were repaired by single row repair technique. Clinical evaluation included visual analogue scale (VAS), range of motion, Korean Shoulder Scoring System (KSS) and American Shoulder and Elbow Society (ASES) score. Ultrasonographic evaluation was performed on cuff integrity and protrusion of proximal nail tip as well. Radiographic evaluation included time to union, protrusion of proximal nail tip and migration of proximal interlocking screw which could affect shoulder joint function. Results: Mean VAS at last follow-up was $1.65{\pm}1.84$ points. Range of motion showed forward flexion of $137.0{\pm}33.5^{\circ}$, external rotation of $43.5{\pm}12.7^{\circ}$ and internal rotation of $16.4{\pm}2.0^{\circ}$ while KSS score and ASES score were $79.6{\pm}20.7$ and $83.7{\pm}17.0$ points, respectively. Bone union was demonstrated in all cases and average time to union was $3.4{\pm}1.3$ months. Migration of proximal interlocking screw was shown in 6 cases (35%). On ultrasonographic evaluation, there were normal in 8 (47%), weaving in 4 (24%), partial tear in 5 cases (29%), but no complete tear. Protrusion of proximal nail tip was demonstrated in 8 cases (47%) on plain radiographs whereas in 11 cases (65%) on ultrasonography and was associated with increasing age (p=0.038). Ultrasonographic weaving and partial tear was associated with protrusion of proximal nail tip (p=006), but not with repair of preoperative tear (p>0.05). Conclusion: Because weaving and partial tear on ultrasonography originated from protrusion of proximal nail tip, careful insertion of nail and meticulous repair of cuff during operation lead to stable fixation with satisfactory recovery of shoulder function follow-up ultrasonography can be a useful tool for evaluating protrusion of nail tip and rotator cuff tear, of which diagnosis is difficult on plain X-ray after antegrade intramedullary nailing for humerus fracture.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.280-287
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• 2007

Purpose : Urinary lithiasis is uncommon in children, however, it may lead to chronic renal insufficiency and even end stage renal disease. The etiology of stone formation in children is largely unknown; although the most common causes are known to be associated with congenital anomalies of the genito-urinary(G-U) tract, urinary tract infections(UTI), and metabolic diseases. Methods : A total of 73 children(male:female=42:31, mean age $6.6{\pm}5.3$ years) presented with urinary lithiasis between Sep. 1998 and Jul. 2007 at Seoul National University Children's Hospital. The medical records were reviewed retrospectively. Results : The most common presenting symptoms were gross hematuria(28/73, 38%) and flank or abdominal pain(23/73, 32%). The stones were located in the upper urinary tract in 48 patients(66%), in the bladder in 18(24%), and in both the bladder and upper urinary tract in 2 (3%). Congenital anomalies of the G-U tract with/without UTI were detected in 30 children (41%), hypercalciuria with/without hypercalcemia in 15(20%), and other metabolic diseases in 8(11%). In 17 patients(23%), no underlying cause of stone formation was detected. The majority of stones were infected stones(24/36, 67%), which were followed by calcium stones(8/36, 22%), uric acid stones(3/36, 8%). and cystine stones(1/36, 3%). Thirty-four patients(46%) underwent surgical procedures and/or extracorporeal shockwave lithotripsy for stone removal, and 13(18%) passed stones spontaneously with/without medical management. Stones recurred in 6 patients(8%): 4 with neurogenic bladder augmented by ileocystoplasty, 1 with cystinuria, and 1 with unknown etiology. Conclusion : The common causes of urinary lithiasis in children were congenital anomalies of the G-U tract with/without UTI and metabolic disorders including hypercalciuria/hypercalcemia. For the management of stones, minimally invasive procedures should be chosen on the basis of accompanying symptoms and the composition, locations and etiology of stones.

• Korean Journal of Materials Research
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• v.11 no.5
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• pp.427-430
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• 2001

We prepared 10cm-diameter Si(100)/500 $\AA$-Si$_3$N$_4$/Si(100) wafer Pairs adopting 500 $\AA$ -thick Si$_3$N$_4$layer as insulating layer between single crystal Si wafers. Si3N, is superior to conventional SiO$_2$ in insulating. We premated a p-type(100) Si wafer and 500 $\AA$ -thick LPCVD Si$_3$N$_4$∥Si (100) wafer in a class 100 clean room. The cremated wafers are separated in two groups. One group is treated to have hydrophobic surface and the other to have hydrophilic. We employed a FLA(fast linear annealing) bonder to enhance the bond strength of cremated wafers at the scan velocity of 0.1mm/sec with varying the heat input at the range of 400~1125W. We measured bonded area using a infrared camera and bonding strength by the razor blade crack opening method. We used high resolution transmission electron microscopy(HRTEM) to probe cross sectional view of bonded wafers. The bonded area of two groups was about 75%. The bonding strength of samples which have hydrophobic surface increased with heat input up to 1577mJ/$m^2$ However, bonding strength of samples which have hydrophilic surface was above 2000mJ/$m^2$regardless of heat input. The HRTEM results showed that the hydrophilic samples have about 25 $\AA$ -thick SiO layer between Si and Si$_3$N$_4$/Si and that maybe lead to increase of bonding strength.

• Development and Reproduction
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• v.13 no.1
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• pp.1-11
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• 2009

Implantation itself is governed by an array of endocrine, paracrine and autocrine modulators, of embryonic and maternal origin. Window of implantation is the unique temporal and spatial expression of factors allows the embryo to implant via signaling, appositioning, attachment, and invasion in a specific time frame of $2{\sim}4$ days. When the embryo has arrived in the uterine cavity, a preprogrammed sequence of events occurs, which involves the production and secretion of a multitude of biochemical factors such as cytokines, growth factors, and adhesion molecules by the endometrium and the embryo, thus leading to the formation of a receptive endometrium. Cytokines such as LIF, CSF-1, and IL-1 have all been shown to play important roles in the cascade of events that leads to implantation. Integrin, L-selectin ligands, glycodelin, mucin-1, HB-EGF and pinopodes are involved in appositioning and attachment. The embryo also produces cytokines and growth factors (ILs, VEGF) and receptors for endometrial signals such as LIF, CSF-1, IGF and HB-EGF. The immune system and angiogenesis play an important role. The usefulness of these factors to assess endometrial receptivity and to estimate the prognosis for pregnancy in natural and artificial cycles remains to be proven. Integrins, pinopodes, glycodelin and LIF (from biopsies) are promising candidates; from uterine flushings, glycodelin and LIF are also candidates. The ideal serum marker is not available, but VEGF, glycodelin and CSF have some clinical implications. Further evaluation that includes larger groups of infertile women and fertile controls are needed to elucidate whether their presence in plasma, flushing fluid, or endometrial samples can be used as some kind of a screening tool to assess endometrial function and prognosis for pregnancy before and after artificial reproductive therapy. A better understanding of their function in human implantation may lead to therapeutic intervention, thereby improving the success rate in reproduction treatment. New molecular techniques are becoming available for measuring both embryonic and endometrial changes prior to and during implantation. The use of predictive sets of markers may prove to be more reliable than a single marker. Ultimately, the aim is to use these tools to increase implantation in artificial cycles and consequently improve live-birth rates.

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.65-82
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• 2015

Recently, there has been a surge of interest in finding core issues and analyzing emerging trends for the future. This represents efforts to devise national strategies and policies based on the selection of promising areas that can create economic and social added value. The existing studies, including those dedicated to the discovery of future promising fields, have mostly been dependent on qualitative research methods such as literature review and expert judgement. Deriving results from large amounts of information under this approach is both costly and time consuming. Efforts have been made to make up for the weaknesses of the conventional qualitative analysis approach designed to select key promising areas through discovery of future core issues and emerging trend analysis in various areas of academic research. There needs to be a paradigm shift in toward implementing qualitative research methods along with quantitative research methods like text mining in a mutually complementary manner. The change is to ensure objective and practical emerging trend analysis results based on large amounts of data. However, even such studies have had shortcoming related to their dependence on simple keywords for analysis, which makes it difficult to derive meaning from data. Besides, no study has been carried out so far to develop core issues and analyze emerging trends in special domains like the aviation industry. The change used to implement recent studies is being witnessed in various areas such as the steel industry, the information and communications technology industry, the construction industry in architectural engineering and so on. This study focused on retrieving aviation-related core issues and emerging trends from overall research papers pertaining to aviation through text mining, which is one of the big data analysis techniques. In this manner, the promising future areas for the air transport industry are selected based on objective data from aviation-related research papers. In order to compensate for the difficulties in grasping the meaning of single words in emerging trend analysis at keyword levels, this study will adopt topic analysis, which is a technique used to find out general themes latent in text document sets. The analysis will lead to the extraction of topics, which represent keyword sets, thereby discovering core issues and conducting emerging trend analysis. Based on the issues, it identified aviation-related research trends and selected the promising areas for the future. Research on core issue retrieval and emerging trend analysis for the aviation industry based on big data analysis is still in its incipient stages. So, the analysis targets for this study are restricted to data from aviation-related research papers. However, it has significance in that it prepared a quantitative analysis model for continuously monitoring the derived core issues and presenting directions regarding the areas with good prospects for the future. In the future, the scope is slated to expand to cover relevant domestic or international news articles and bidding information as well, thus increasing the reliability of analysis results. On the basis of the topic analysis results, core issues for the aviation industry will be determined. Then, emerging trend analysis for the issues will be implemented by year in order to identify the changes they undergo in time series. Through these procedures, this study aims to prepare a system for developing key promising areas for the future aviation industry as well as for ensuring rapid response. Additionally, the promising areas selected based on the aforementioned results and the analysis of pertinent policy research reports will be compared with the areas in which the actual government investments are made. The results from this comparative analysis are expected to make useful reference materials for future policy development and budget establishment.

• Journal of Intelligence and Information Systems
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• v.18 no.1
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• pp.125-141
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• 2012

These days, the malicious attacks and hacks on the networked systems are dramatically increasing, and the patterns of them are changing rapidly. Consequently, it becomes more important to appropriately handle these malicious attacks and hacks, and there exist sufficient interests and demand in effective network security systems just like intrusion detection systems. Intrusion detection systems are the network security systems for detecting, identifying and responding to unauthorized or abnormal activities appropriately. Conventional intrusion detection systems have generally been designed using the experts' implicit knowledge on the network intrusions or the hackers' abnormal behaviors. However, they cannot handle new or unknown patterns of the network attacks, although they perform very well under the normal situation. As a result, recent studies on intrusion detection systems use artificial intelligence techniques, which can proactively respond to the unknown threats. For a long time, researchers have adopted and tested various kinds of artificial intelligence techniques such as artificial neural networks, decision trees, and support vector machines to detect intrusions on the network. However, most of them have just applied these techniques singularly, even though combining the techniques may lead to better detection. With this reason, we propose a new integrated model for intrusion detection. Our model is designed to combine prediction results of four different binary classification models-logistic regression (LOGIT), decision trees (DT), artificial neural networks (ANN), and support vector machines (SVM), which may be complementary to each other. As a tool for finding optimal combining weights, genetic algorithms (GA) are used. Our proposed model is designed to be built in two steps. At the first step, the optimal integration model whose prediction error (i.e. erroneous classification rate) is the least is generated. After that, in the second step, it explores the optimal classification threshold for determining intrusions, which minimizes the total misclassification cost. To calculate the total misclassification cost of intrusion detection system, we need to understand its asymmetric error cost scheme. Generally, there are two common forms of errors in intrusion detection. The first error type is the False-Positive Error (FPE). In the case of FPE, the wrong judgment on it may result in the unnecessary fixation. The second error type is the False-Negative Error (FNE) that mainly misjudges the malware of the program as normal. Compared to FPE, FNE is more fatal. Thus, total misclassification cost is more affected by FNE rather than FPE. To validate the practical applicability of our model, we applied it to the real-world dataset for network intrusion detection. The experimental dataset was collected from the IDS sensor of an official institution in Korea from January to June 2010. We collected 15,000 log data in total, and selected 10,000 samples from them by using random sampling method. Also, we compared the results from our model with the results from single techniques to confirm the superiority of the proposed model. LOGIT and DT was experimented using PASW Statistics v18.0, and ANN was experimented using Neuroshell R4.0. For SVM, LIBSVM v2.90-a freeware for training SVM classifier-was used. Empirical results showed that our proposed model based on GA outperformed all the other comparative models in detecting network intrusions from the accuracy perspective. They also showed that the proposed model outperformed all the other comparative models in the total misclassification cost perspective. Consequently, it is expected that our study may contribute to build cost-effective intelligent intrusion detection systems.

• Journal of the Korean Society of Food Culture
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• v.11 no.4
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• pp.455-463
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• 1996

A survey was conducted to investigate the perceptions of health and foods, and the food habits among the elderly men who came to the Tap-Gol park on a daily basis. A total of 253 subjects were selected for this study. The data was analyzed through the $X^2-test$, Duncan's multiple range test and Pearson Correlation by the use of SAS program. The results were as follows. The majority of the subjects were in their 70's. 56.1% of them lived with their sons' families, 9.1% lived alone, and 27.3% lived with a spouse. 32% of the subjects were living with the expense less than 50,000 won per month. Although some were suffering from such diseases as arthritis, indigestion, and hypertension etc., the subjects were generally in good health. Their dependance on dietary supplements were insignificant. Most of the subject had a common-sensible notion as to health. They put emphasis on the three factors for the maintenance of good health: a balanced diet, a peace of mind and exercising. With regard to the food habits, the majority were fair in general. The subject living with family had more regular meals than the single people did. 41.5% of the subjects responded that they had irregular meals, mainly for lunch due to a poor appetite or a financial problem. The respondents cited protein food, milk, fruit, sea weeds and food cooked with oil as conducive to good health. But what they consumed did not match what they thought was good, particularly milk. The results of this study lead to the suggestion that Korea need to develop such a lunch program for the elderly as is practiced in the U.S., through which dietary motivation can be stimulated and a low-priced and balanced diet offered at least for one meal a day.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.637-648
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• 2009

As the cost of disks decreases, PCs are soon expected to be equipped with a disk of 1TB or more. Assuming that a single person generates 1GB of data per month, 1TB is enough to store data for the entire lifetime of a person. This has lead to the growth of researches on lifelog management, which manages what people see and listen to in everyday life. Although many different lifelog management systems have been proposed, including those based on the relational data model, based on ontology, and based on file systems, they have all advantages and disadvantages: Those based on the relational data model provide good query processing performance but they do not support complex queries properly; Those based on ontology handle more complex queries but their performances are not satisfactory: Those based on file systems support only keyword queries. Moreover, these systems are lack of support for lifelog group management and do not provide a convenient user interface for modifying and adding tags (metadata) to lifelogs for effective lifelog search. To address these problems, we propose a lifelog management system based on the relational data model. The proposed system models lifelogs by using the relational data model and transforms queries on lifelogs into SQL statements, which results in good query processing performance. It also supports a simplified relationship query that finds a lifelog based on other lifelogs directly related to it, to overcome the disadvantage of not supporting complex queries properly. In addition, the proposed system supports for the management of lifelog groups by providing ways to create, edit, search, play, and share them. Finally, it is equipped with a tagging tool that helps the user to modify and add tags conveniently through the ion of various tags. This paper describes the design and implementation of the proposed system and its various applications.

• The Journal of Korean Society for School & Community Health Education
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• v.4
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• pp.117-139
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• 2003

The purpose of this research lies in presenting logical viability for the measures that curtail access to lewd Internet contents by middle school students amidst the reality in which lewd contents are circulated freely through the Internet, a medium that the middle school students find most easy to access. In order to establish right form of awareness towards sex, this research identified the ways they access the lewd Internet contents, their reaction after the exposure to those contents, their knowledge of sex, their concerns regarding sex and their accessibility to sexual activities in order to conduct a comparative analysis on the relationship between lewd Internet contents and their awareness of sex. First, realities of accessing lewd Internet contents and reactions according to the demographics of middle school students There isa significant difference in the experience of accessing lewd Internet contents in terms of gender. Mostly, male students tend to access the contents more. As for the way they access the lewd Internet contents, both male and female students replied that they access through spam mail of lewd nature. Thus, measures to address this problem are needed urgently. As to when they first accessed the lewd contents, most of the research subjects replied that they accessed either in elementary school period or in the early middle school period. This shows that most of the students got exposed to lewd contents even before they could establish positive, correct awareness of sex. Thus, there is a risk that they may formulate wrong kind of sexual awareness. Accordingly, it is necessary to develop measures through focused sex education. Students are divided into two groups according to the time they spend on the contents averagely: those who spend over one hour and those who spend less than an hour on the lewd contents. If the students spending longer hours are not to be checked and properly guided, it may lead to increasing cases of sexual delinquencies due to their wrongly formed awareness of sex. When the question of existence(non-existence) of guardian was addressed, students with both parents tend to access the lewd Internet contents in a more diverse manner and tend to access more compared to those students from single parent or no-parent families. Accordingly, guardians need to pay attention to how their children are using the Internet. Second, awareness of sex depending on the middle school students' demographics In case of sexual knowledge, middle school students shows relatively high level of knowledge. In particular, female students are found more knowledgeable than male students, and the students in upper years are more knowledgeable as well. As a result, this research recommends that the students in lower years should be guided with more basc and detailed information, while those in upper years need to be taught to form and express their own thoughts and attitudes and to build up independence on this matter. In case of worries about sex, both male and female students don't worry too much about it. However, male students are more concerned about sex than female students in a more diverse ways. As for the differences by academic year, concerns for sex increase, as students get older. Accordingly, sex education that helps establish sound perception of the opposite sex and that focuses on the etiquettes that one must adhere to at the presence of the opposite sex need to be conducted against middle school students. In case of accessibility to sex, male students manifest higher tendency than female students. As for the differences by academic year, those in the first and second years show higher accessibility than those in their third year. In general, younger students tend to be more open-minded toward sex. Accordingly, students in lower academic years need to undergo basic knowledge oriented sex education, whereas those in upper academic years need to undergo discussion centered sex education where they subject to questions regarding their attitude and opinion. Third, relationship between the reactions after the exposure to the lewd Internet contents and their awareness of sex As the frequency of contact with lewd Internet contents increases, awareness of sex increases as well. Thus, the lewd Internet contents contribute to the increase in students' concern for sex as well as increase in accessibility to sex, which eventually become barriers to students' establishment of a healthy perception of sex. Reactions to sex after the exposure to lewd Internet contents and awareness of sex indicate a significant correlation. However, negative correlation is manifested with knowledge of sex. Thus, it is possible to know that the greater access to lewd Internet contents does not necessarily translate into increase in knowledge of sex. However, the study showed there is a correlation between concerns for sex and the level of accessibility to sex. In more detail, the more reactions to the contents they show, the more concerns for sex they have and the more positively they take acceptability to sex. Moreover, it is necessary to develop necessary measures since textbooks today do not include measures needed to address the lewd Internet contents. Given the above findings, it is necessary to continue to complement structural measures in order to prevent easy access of lewd Internet contents by middle school students. Moreover, it is necessary to be considerate of the students so that they themselves can form a healthy Internet culture and grow up within positive framework for the sex education.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.451-464
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• 2022

The high-level nuclear waste repository is a deep geological disposal system exposed to complex environmental conditions such as high temperature, radiation, and ground-water due to handling spent nuclear fuel. Continuous exposure can lead to cracking and deterioration of the structure over time. On the other hand, the high-level nuclear waste repository requires an ultra-long life expectancy. Thus long-term structural health monitoring is essential. Various sensors such as an accelerometer, earth pressure gauge, and displacement meter can be used to monitor the health of a structure, and a piezoelectric sensor is generally used. Therefore, it is necessary to develop a highly durable sensor based on the durability assessment of the piezoelectric sensor. This study designed an accelerated life test for durability assessment and life prediction of the piezoelectric sensor. Based on the literature review, the number of accelerated stress levels for a single stress factor, and the number of samples for each level were selected. The failure mode and mechanism of the piezoelectric sensor that can occur in the environmental conditions of the high-level waste repository were analyzed. In addition, two methods were proposed to investigate the maximum harsh condition for the temperature stress factor. The reliable operating limit of the piezoelectric sensor was derived, and a reasonable accelerated stress level was set for the accelerated life test. The suggested methods contain economical and practical ideas and can be widely used in designing accelerated life tests of piezoelectric sensors.