• Journal of Chest Surgery
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• v.42 no.3
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• pp.317-323
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• 2009

Background: Although high efficiency of conversion into sinus rhythm has been demonstrated after performing the Cox-Maze procedure in patients with atrial fibrillation associated with mitral valve disease, the changes in the mechanical function and size of the left atrium have not been determined. The aim of the study was to evaluate the effect of the Maze procedure on the left atrial size and contractile transport function. Material and Method: From July 1997 to July 2008, 647 consecutive patients were operated on for chronic atrial fibrillation associated with mitral valve disease. Among these, 211 patients that (1) were able to be followed up for 2 years after surgery, (2) had sustained normal sinus rhythm, regardless of whether they were taking anti-arrhythmic medications and (3) did not have valvular regurgitation greater than grade III or they did not have moderate grade valvular stenosis were selected for evaluation. The left atrial size and contractile transport function were assessed by transthoracic echocardiography at the postoperative base line (1 year) and at regular follow-up periods (2 years, 3 years, 4 years and 6 year). Result: The left atrial dimension was increased and the contractile transport function was decreased during the follow-up period. The longer the follow-up period, the greater was the statistical significance of the left atrial size increase and contractile transport function decrease. Conclusion: In patients who sustain normal sinus rhythm conversion after a Maze III procedure with a mitral valve operation, there is a gradual increase of the left atrial dimensions and a decrease of contractile transport function during the follow-up period. Therefore, scrupulous follow-up is needed for these patients.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.113-122
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• 2010

Purpose: To evaluate the accuracy of a target position at static and dynamic state by using Dynamic phantom for the difference between tumor's actual movement during respiratory gated radiation therapy and skin movement measured by RPM (Real-time Position Management). Materials and Methods: It self-produced Dynamic phantom that moves two-dimensionally to measure a tumor moved by breath. After putting marker block on dynamic phantom, it analyzed the amplitude and status change depending on respiratory time setup in advance by using RPM. It places marker block on dynamic phantom based on this result, inserts Gafchromic EBT film into the target, and investigates 5 Gy respectively at static and dynamic state. And it scanned investigated Gafchromic EBT film and analyzed dose distribution by using automatic calculation. Results: As a result of an analysis of Gafchromic EBT film's radiation amount at static and dynamic state, it could be known that dose distribution involving 90% is distributed within margin of error of 3 mm. Conclusion: As a result of an analysis of dose distribution's change depending on patient's respiratory cycle during respiratory gated radiation therapy, it is expected that the treatment would be possible within recommended margin of error at ICRP 60.

• Journal of Chest Surgery
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• v.37 no.8
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• pp.672-683
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• 2004

Background: The treatment results of the advanced lung carcinoma is not satisfactory with the present therapeutic modalities: surgical resection, anti-cancer chemotherapy, and radiotherapy or combination therapy. To predict the prognosis of the non-small-cell lung carcinoma, TNM classification has been was as the basic categorization; however, it has been not satisfactory. It is necessary to consider the causes and the prognosis of the lung carcinoma from another points of view rather the conventional methods. We intended to find out the relationship between the major apoptotic factor, p53 gene and the prognosis of the patient with lung carcinoma. Material and Method: Three hundreds and fifty-nine patients with lung carcinoma who underwent surgery were analysed. We observed p53 protein accumulated in the cellular nuclei. The p53 protein was detected by immuno-histo-chemical method. We collected information of the patient retrospectively. Result: p53 protein densities were observed in 40% in average as a whole. The protein density was 44 percent in man, 25 percent in woman, 49 percent in the squamous cell carcinoma, and 38 percent in the adenocarcinoma. There were significant correlations between the p53 protein density and the mortality in the squamous cell carcinoma (p=0.025), follow-up duration in TNM stage I group (p=0.010), and follow-up duration in the lobectomy patient group (p=0.043), and tumor cell differentiation (p=0.009). p53 protein densities were significantly different between the lobectomy and the pneumonectomy group (p=0.044). Conclusion: The authors found that p53 protein had some correlations with the prognosis of the lung cancer partially in some factors. We suggest the p53 protein density could be used as a marker of prognosis in the non-small-cell lung carcinoma.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.10 no.1
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• pp.51-59
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• 2007

Purpose: Recently well-developed anorectal function tests have revealed that there is an obvious pelvic floor dyssynergia (PFD) pattern in pediatric patients with constipation, as well as in adult's. The use of biofeedback therapy (BT) has been widely implemented in adult PFD patients; however, this approach has only rarely been considered for pediatric PFD patients. Therefore, we assessed the effectiveness of BT in children with PFD. Methods: We studied 70 children with PFD, who were referred to the department of pediatrics at the Asan Medical Center for the management of soiling or chronic constipation from September 2002 to February 2005. Diagnosis of PFD and assessment of the efficacy of BT for PFD treatment were carried out along with several ano-rectal function tests (cine-defecography, ano-rectal manometry, balloon expulsion test and intra-anal EMG); in addition, a questionnaire was administered. The BT based intra-anal EMG was performed. A follow-up telephone interview was performed more than 6 months later. Results: Most of the symptoms and results of the ano-rectal function tests were statistically improved after BT. In comparisons between the BT and control groups (BT refusal group due to poor compliance), the symptoms were statistically improved at follow-up. Therefore, for the shortterm improvement of symptoms, BT was better than conservative therapy alone. The negative feelings associated with ano-rectal function testing and BT were directly associated with failure or success of therapy. Conclusion: Pediatric patients with constipation or soiling that presented with an obvious PFD pattern showed that BT was a useful therapeutic tool for rapid improvement of symptoms.

• Journal of Gifted/Talented Education
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• v.13 no.4
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• pp.65-94
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• 2003

The purpose of this study is to acquire the information on the current situation of students' selection process in order to renovate the system of picking up the students. As a first step of the study, we examined the validity of the factors of the single-out system such as qualification and the process for the application and the standards and proceeding of the selection. Then we analysed the result of the entrance examination of Hansung Science Highschool in 2002. The analysis was on the correlation between the result of entrance examination and the achievement in the school and the decision of the course after graduation. To know on the achievement of the students, we investigated the records of regular tests and asked the teachers' opinion in math and science classes. As a result, we gained the following points: First, the present single-out system has a danger of excluding students who are much talented in science and math field because it is based on students' achievements in middle schools; Second, the new selection system should consider the character and attitude of the applicants in addition to their knowledge; Third, the continuous observation of the teacher in middle school should be an important factor of the picking up system; Fourth, more questions requiring divergent thinking ability and inquiry skill should be developed as selective examination question. Also examination questions should cover the various contents from mathematics to science, and do not affect pre-learning; Finally, the system of present letting all students stand in one line should be changed into that of letting students in various lines. We can consider using multi-step selection system.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.2
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• pp.81-89
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• 2011

The results of tracking the symbolism of plants in the introduction factors of Sokhwa(folk painting) are as the following. 1. The term Sokhwa(俗畵) is not only a type of painting with a strong local customs, but also carries a symbolic meaning and was discovered in "Donggukisanggukjip" of Lee, Gyu-Bo(1268~1241) in the Goryo era as well as the various usage in the "Sok Dongmunseon" in the early Chosun era, "Sasukjaejip" of Gang, Hee-mang(1424~1483), "Ilseongrok(1786)" in the late Chosun era, "Jajeo(自著)" of Yoo, Han-joon(1732~1811), and "Ojuyeonmunjangjeonsango(五洲衍文長箋散稿)" of Lee, Gyu-gyung(1788~?). Especially, according to the Jebyungjoksokhwa allegation〈題屛簇俗畵辯證說〉in the Seohwa of the Insa Edition of Ojuyeonmunjangjeonsango, there is a record that the "people called them Sokhwa." 2. Contemporarily, the Korean Sokhwa underwent the prehistoric age that primitively reflected the natural perspective on agricultural culture, the period of Three States that expressed the philosophy of the eternal spirits and reflected the view on the universe in colored pictures, the Goryo Era that religiously expressed the abstract shapes and supernatural patterns in spacein symbolism, and the Chosun Era that established the traditional Korean identity of natural perspective, aesthetic values and symbolism in a complex integration in the popular culture over time. 3. The materials that were analyzed in 1,009 pieces of Korean Sokhwa showed 35 species of plants, 37 species of animals, 6 types of natural objects and other 5 types with a total of 83 types. 4. The shape aesthetics according to the aesthetic analysis of the plants in Sokhwa reflect the primitive world view of Yin/yang and the Five Elements in the peony paintings and dynamic refinement and biological harmonies in the maehwado; the composition aesthetics show complex multi-perspective composition with a strong noteworthiness in the bookshelf paintings, a strong contrast of colors with reverse perspective drawing in the battlefield paintings, and the symmetric beauty of simple orderly patterns in nature and artificial objects with straight and oblique lines are shown in the leisurely reading paintings. In terms of color aesthetics, the five colors of directions - east, west, south, north and the center - or the five basic colors - red, blue, yellow, white and black - are often utilized in ritual or religious manners or symbolically substitute the relative relationships with natural laws. 5. The introduction methods in the Korean Sokhwa exceed the simple imitation of the natural shapes and have been sublimated to the symbolism that is related to nature based on the colloquial artistic characteristics with the suspicion of the essence in the universe. Therefore, the symbolism of the plants and animals in the Korean Sokhwas is a symbolic recognition system, not a scientific recognition system with a free and unique expression with a complex interaction among religious, philosophical, ecological and ideological aspects, as a identity of the group culture of Koreans where the past and the future coexist in the present. This is why the Koran Sokhwa or the folk paintings can be called a cultural identity and can also be interpreted as a natural and folk meaningful scenic factor that has naturally integrated into our cultural lifestyle. However, the Sokhwa(folk paintings) that had been closely related to our lifestyle drastically lost its meaning and emotions through the transitions over time. As the living lifestyle predominantly became the apartment culture and in the historical situations where the confusion of the identity has deepened, the aesthetic and the symbolic values of the Sokhwa folk paintings have the appropriateness to be transmitted as the symbolic assets that protect our spiritual affluence and establish our identity.

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.119-142
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• 2015

With the explosive growth in the volume of information, Internet users are experiencing considerable difficulties in obtaining necessary information online. Against this backdrop, ever-greater importance is being placed on a recommender system that provides information catered to user preferences and tastes in an attempt to address issues associated with information overload. To this end, a number of techniques have been proposed, including content-based filtering (CBF), demographic filtering (DF) and collaborative filtering (CF). Among them, CBF and DF require external information and thus cannot be applied to a variety of domains. CF, on the other hand, is widely used since it is relatively free from the domain constraint. The CF technique is broadly classified into memory-based CF, model-based CF and hybrid CF. Model-based CF addresses the drawbacks of CF by considering the Bayesian model, clustering model or dependency network model. This filtering technique not only improves the sparsity and scalability issues but also boosts predictive performance. However, it involves expensive model-building and results in a tradeoff between performance and scalability. Such tradeoff is attributed to reduced coverage, which is a type of sparsity issues. In addition, expensive model-building may lead to performance instability since changes in the domain environment cannot be immediately incorporated into the model due to high costs involved. Cumulative changes in the domain environment that have failed to be reflected eventually undermine system performance. This study incorporates the Markov model of transition probabilities and the concept of fuzzy clustering with CBCF to propose predictive clustering-based CF (PCCF) that solves the issues of reduced coverage and of unstable performance. The method improves performance instability by tracking the changes in user preferences and bridging the gap between the static model and dynamic users. Furthermore, the issue of reduced coverage also improves by expanding the coverage based on transition probabilities and clustering probabilities. The proposed method consists of four processes. First, user preferences are normalized in preference clustering. Second, changes in user preferences are detected from review score entries during preference transition detection. Third, user propensities are normalized using patterns of changes (propensities) in user preferences in propensity clustering. Lastly, the preference prediction model is developed to predict user preferences for items during preference prediction. The proposed method has been validated by testing the robustness of performance instability and scalability-performance tradeoff. The initial test compared and analyzed the performance of individual recommender systems each enabled by IBCF, CBCF, ICFEC and PCCF under an environment where data sparsity had been minimized. The following test adjusted the optimal number of clusters in CBCF, ICFEC and PCCF for a comparative analysis of subsequent changes in the system performance. The test results revealed that the suggested method produced insignificant improvement in performance in comparison with the existing techniques. In addition, it failed to achieve significant improvement in the standard deviation that indicates the degree of data fluctuation. Notwithstanding, it resulted in marked improvement over the existing techniques in terms of range that indicates the level of performance fluctuation. The level of performance fluctuation before and after the model generation improved by 51.31% in the initial test. Then in the following test, there has been 36.05% improvement in the level of performance fluctuation driven by the changes in the number of clusters. This signifies that the proposed method, despite the slight performance improvement, clearly offers better performance stability compared to the existing techniques. Further research on this study will be directed toward enhancing the recommendation performance that failed to demonstrate significant improvement over the existing techniques. The future research will consider the introduction of a high-dimensional parameter-free clustering algorithm or deep learning-based model in order to improve performance in recommendations.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.73-79
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• 1991

Between January 1980 and September 1988,08 patients with advanced T3 & T4 glottic carcinoma were treated with RT and surgery/RT in the Department of Radiation Oncology, Yonsei Cancer Center and ENT, Yonsei University College of Medicine. The mean age was 60 years old (range 33 to 79 years old). The 34 patients were treated with irradiation alone, and the remaining 34 patients with surgery and irradiation. Initial nodal presentation was $37\% (25/68);\;31\%$ (l1/34) in RT alone group and $41\%$ (14/34) in combined treatment group. The minimum follow-up was 2 years. The local control rate after treatment was $47\%$ in RT alone group and $65\%$ in combined treatment group; $57\%$ for node negative and $27\%$ for node positive patients treated with RT alone; $65\%$ for node negative and $54\%$ for node positive patients treated with combined treatment. The treatment failure was observed in 30 patients; 14 patients for primary local failure, 6 patients for regional nodal failure,5 patients for local and regional failure, 26 patients for primary failure and/or distant metastasis, and 2 patient for regional failure and/or distant metastasis. The overall 5-year suwival rate was $57\%;\;37\%$ in RT alone group and $70\%$ in combined treatment group; $55\%$ for node negative and $20\%$ for node positive patients treated with RT alone; $73\%$ for node negative and $77\%$ for node positive patients treated with combined treatment. In conclusion, the combined treatment groups in the treatment of advanced 73 and 74 glottic cancer showed the better results in local control rates and S-year actuarial survival rates than RT alone group. We suggest that total laryngectomy and postoperative RT in the most patients of advanced glottic cancer were performed. However, in cases of node negative patints, RT alone is prefer as a treatment modality over combined surgery and RT since the treatment results were comparable and furthermore functional preservation could be achieved.

• Journal of Preventive Medicine and Public Health
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• v.32 no.4
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• pp.452-458
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• 1999

Objectives: The authors conducted the study to evaluate bias when potentially diseased subjects were included in cohort members while analyzing risk factors of chronic liver diseases. Methods: Total of 14,529 subjects were followed up for the incidence of liver diseases from January 1993 to June 1997. We have used databases of insurance company with medical records, cancer registry, and death certificate data to identify 102 incident cases. The cohort members were classified into potentially diseased group(n=2,217) when they were HBsAg positive, serum GPT levels higher than 40 units, or had or has liver diseases in baseline surveys. Cox's model were used for potentially diseased group, other members, and total subjects, respectively. Results: The risk factors profiles were similar for total and potentially diseased subjects: HBsAg positivity, history of acute liver disease, and recent quittance of smoking or drinking increased the risk. while intake of pork and coffee decreased it. For the potentially diseased, obesity showed marginally significant protective effect. Analysis of subjects excluding the potentially diseased showed distinct profiles: obesity increased the risk, while quitting smoking or drinking had no association. For these intake of raw liver or processed fish or soybean paste stew increased risk; HBsAg positivity, higher levels of liver enzymes and history of acute liver diseases increased the risk. Conclusions: The results suggested the potential bias in risk ratio estimates when potentially diseased subjects were included in cohort study on chronic liver diseases, especially for lifestyles possibly modified after disease onset. The analytic strategy excluding potentially diseased subjects was considered appropriate for identifying risk factors for chronic liver diseases.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.97-104
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• 1997

of $PLC-\gamma$ 1 activity. Results : In the immunohistochemistry, the expression of $PLC-\beta$ was negative for all grnups. The expression of $PLC-\gamma$ 1 was highest in the group III followed by group II in the proliferative zone of mucosa. The expression of PKC-01 was strong1y positive in group I followed by group II in the damaged surface epithelium. The above findings were also confirmed in the immunoblotting study. In the irnrnunoblotting study, the expressions of $PLC-\beta,\;PLC-\gamma\;1,\;and\;PLC-\delta$ were the same as the results of immunohistochemistry The expression of ras oncoprotein was weakly Positive in groups II, III and IV. The of EGFR was the highest in the group II, III, followed by group W and the expression of PKC was weakly positive in the group II and III. Conclusion : $PLC-\gamma$ 1 mediated signal transduction including ras oncoprotein, EGFR, and PKC play a significant role irL mucosal regeneration after irradiation. $PLC-\delta$ 1 mediated signal transduction might have an important role in mucosal damage after irradiation. Further studies will be necessary to confirm the signal transduction mediating the $PLC-\delta$ 1.