• Journal of Gastric Cancer
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• v.6 no.4
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• pp.244-249
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• 2006

Purpose: Tumor size has been reported to be one of the prognostic factors in the preoperative setting and 8 cm has been confirmed as a cut-off value for large gastric tumors with respect to postoperative complications. The aim of this study was to investigate the clinicopathologic features and the prognosis in patients with tumors larger than 8 cm in diameter. Materials and Methods: We retrospectively studied 2,260 patients with gastric cancer who underwent a gastrectomy from 1983 to 2001 at the Department of Surgery, Korea University College of Medicine. For a comparative analysis we divided the cases into the large and the small groups according to tumor size. The clinicopathological factors associated with large gastric tumors were analyzed by using univariate and multivariate analyses. To determine which variables were independent prognostic factors for overall survival, we applied the Cox proportional hazards model and we used P<0.05 as the cutoff value for statistical significance. Results: Univariate and multivariate analyses disclosed that tumor location (P<0.001), resection type (P<0.001), curability (P<0.001), depth of invasion (P<0.001), number of metastatic lymph nodes (P<0.001), differentiation (P<0.001) and combined resection (P<0.001) were significantly different between the two groups. The independent factors for survival identified by using the Cox proportional hazards model for large gastric tumors were nodal status (P<0.001), curative resection (P<0.001), depth of invasion (P=0.010), type of resection (P=0.018) and age (P=0.033). Conclusion: Large gastric tumors showed more aggressive local findings than their smaller counterparts. In patients with large gastric tumors, a curative resection was the most important factor for the prognosis. Therefore, we suggest that every effort should be made to do a curative gastrectomy and an accurate preoperative examination. (J Korean Gastric Cancer Assoc 2006;6:244-249)

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.99-118
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• 2015

Object-oriented programming languages have been widely selected for developing modern information systems. The use of concepts relating to object-oriented (OO, in short) programming has reduced efforts of reusing pre-existing codes, and the OO concepts have been proved to be a useful in interpreting system requirements. In line with this, we have witnessed that a modern conceptual modeling approach supports features of object-oriented programming. Unified Modeling Language or UML becomes one of de-facto standards for information system designers since the language provides a set of visual diagrams, comprehensive frameworks and flexible expressions. In a modeling process, UML users need to consider relationships between classes. Based on an explicit and clear representation of classes, the conceptual model from UML garners necessarily attributes and methods for guiding software engineers. Especially, identifying an association between a class of part and a class of whole is included in the standard grammar of UML. The representation of part-whole relationship is natural in a real world domain since many physical objects are perceived as part-whole relationship. In addition, even abstract concepts such as roles are easily identified by part-whole perception. It seems that a representation of part-whole in UML is reasonable and useful. However, it should be admitted that the use of UML is limited due to the lack of practical guidelines on how to identify a part-whole relationship and how to classify it into an aggregate- or a composite-association. Research efforts on developing the procedure knowledge is meaningful and timely in that misleading perception to part-whole relationship is hard to be filtered out in an initial conceptual modeling thus resulting in deterioration of system usability. The current method on identifying and classifying part-whole relationships is mainly counting on linguistic expression. This simple approach is rooted in the idea that a phrase of representing has-a constructs a par-whole perception between objects. If the relationship is strong, the association is classified as a composite association of part-whole relationship. In other cases, the relationship is an aggregate association. Admittedly, linguistic expressions contain clues for part-whole relationships; therefore, the approach is reasonable and cost-effective in general. Nevertheless, it does not cover concerns on accuracy and theoretical legitimacy. Research efforts on developing guidelines for part-whole identification and classification has not been accumulated sufficient achievements to solve this issue. The purpose of this study is to provide step-by-step guidelines for identifying and classifying part-whole relationships in the context of UML use. Based on the theoretical work on Meta-model Formalization, self-check forms that help conceptual modelers work on part-whole classes are developed. To evaluate the performance of suggested idea, an experiment approach was adopted. The findings show that UML users obtain better results with the guidelines based on Meta-model Formalization compared to a natural language classification scheme conventionally recommended by UML theorists. This study contributed to the stream of research effort about part-whole relationships by extending applicability of Meta-model Formalization. Compared to traditional approaches that target to establish criterion for evaluating a result of conceptual modeling, this study expands the scope to a process of modeling. Traditional theories on evaluation of part-whole relationship in the context of conceptual modeling aim to rule out incomplete or wrong representations. It is posed that qualification is still important; but, the lack of consideration on providing a practical alternative may reduce appropriateness of posterior inspection for modelers who want to reduce errors or misperceptions about part-whole identification and classification. The findings of this study can be further developed by introducing more comprehensive variables and real-world settings. In addition, it is highly recommended to replicate and extend the suggested idea of utilizing Meta-model formalization by creating different alternative forms of guidelines including plugins for integrated development environments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6089-6098
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• 2015

This study purposes to identify the effects of performance of public health services (PHS) and personal characteristics on community image to public hospitals. The subjects of this study were 33 public hospitals and 1,789 community residents. The data of '2011 Public hospital evaluation programme' were utilized in this study. The personal characteristics consisted of nine items which were gender, age, education, occupation, monthly incomes, medical security, use experience, health state, and location type. The PHS performance consisted of five items which were number of doctors, number of nurses, total number of staff, budget per 1,000 community residents, and amount of activities per 1,000 community residents. The cronbach's alpha of community image instrument was 0.916. As the results of logistic regression, the significant variables of community image, were age (OR=0.34, 95% CI=0.19-0.60), education (OR=3.03, 95% CI=1.60-5.76), use experience (OR=0.57, 95% CI=0.40-0.81), health state (OR=0.69 95% CI=0.49-0.96), location type (OR=2.10, 95% CI=1.11-3.99), and amount of activities per 1,000 community residents (OR=0.58, 95% CI=0.35-0.96). Community image is very important to public hospitals. The workforce and budget related PHS were significantly demanded to improve community image. The Central and Local government should support to public hospitals to perform PHS effectively.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.790-798
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• 1999

Background: As the early outcome after coronary artery bypass grafting(CABG) has been stabilized, neurologic complication has now become one of the most important morbidity. The aim of this study was to find out the risk factors associated with the neurologic complications after CABG. Material and Method: In 351 patients who underwent CABG, the incidence and features of neurologic complications, with associated perioperative risk factors, were retrospectively reviewed. Neurologic complication was defined as a new cerebral infarction confirmed by postoperative neurologic examination and radiologic studies, or delayed recovery of consciousness and orientation for more than 24 hours after the operation. Result: Neurologic complications occurred in 18 patients(5.1%), of these nine(2.6%) were diagnosed as having new cerebral infarctions(stroke). Stroke was manifested as motor paralysis in four patients, mental retardation or orientation abnormality in four, and brain death in one. Statistical analysis revealed the following variables as significant risk factors for neurologic complications by both univariate and multivariate analyses: cardiopulmonary bypass longer than 180 minutes, atheroma of the ascending aorta, carotid artery stenosis detected by Duplex sonography, and past history of cerebrovascular accident or transient ischemic attack. Age over 65 years, aortic calcification detected by simple X-ray, and intraoperative myocardial infarction were significant risk factors by univariate analysis only. Neither the severity of carotid artery stenosis nor technical modifications such as cannulation of the aortic arch or single clamp technique, which were expected to affect the inciden e of neurologic complications, had significant relationship with the incidence. Conclusion: This study confirmed the strong association between neurologic complications after CABG and atherosclerosis of the arterial system. Therefore, to minimize the incidence of neurologic complications, systematic evaluation focused on atherosclerotic lesions of the arterial system followed by adequate alteration of operative strategy is needed.

• Proceedings of the KOR-KST Conference
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• 1995.12a
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• pp.45-73
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• 1995

The current paper presents a system dynamics model which can generate the land use anq transportation system performance simultaneously is proposed. The model system consists of 7 submodels (population, migration of population, household, job growth-employment-land availability, housing development, travel demand, and traffic congestion level), and each of them is designed based on the causality functions and feedback loop structure between a large number of physical, socio-economic, and policy variables. The important advantages of the system dynamics model are as follows. First, the model can address the complex interactions between land use and transportation system performance dynamically. Therefore, it can be an effective tool for evaluating the time-by-time effect of a policy over time horizons. Secondly, the system dynamics model is not relied on the assumption of equilibrium state of urban systems as in conventional models since it determines the state of model components directly through dynamic system simulation. Thirdly, the system dynamics model is very flexible in reflecting new features, such as a policy, a new phenomenon which has not existed in the past, a special event, or a useful concept from other methodology, since it consists of a lots of separated equations. In Chapter I, II, and III, overall approach and structure of the model system are discussed with causal-loop diagrams and major equations. In Chapter V _, the performance of the developed model is applied to the analysis of the impact of highway capacity expansion on land use for the area of Montgomery County, MD. The year-by-year impacts of highway capacity expansion on congestion level and land use are analyzed with some possible scenarios for the highway capacity expansion. This is a first comprehensive attempt to use dynamic system simulation modeling in simultaneous treatment of land use and transportation system interactions. The model structure is not very elaborate mainly due to the problem of the availability of behavioral data, but the model performance results indicate that the proposed approach can be a promising one in dealing comprehensively with complicated urban land use/transportation system.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.160-171
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• 2002

The impact of summer monsoon on water quality of the lower Nakdong River was evaluated during the summer (June-August) in 1997. Several limnological variables were measured in the interval of $1{\sim}3$ day using an automatic monitoring system (Hydrolab $Recorder^{TM}$) to detect water quality changes caused by rainfall on onehour basis. During the monsoon period (from late June to mid July), 5 times of major rainfall events of >50 mm were recorded in the river basin. Dynamic changes of water quality were observed during the monsoon, and the first rainfall event (June$25{\sim}27$) had a significant influence on the water quality at the lower part of the river. All Parameters were largely changed due to the first rain event, and the changed level was maintained until the end of monsoon period. Nutrient concentrations and turbidity increased and values of the other parameters were declined as a result of water dilution. This rainfall event, Changma, is a meteorological phenomenon caused by the East-Asian monsoon climate. The magnitude and frequency of the rainfall during the early monsoon play an important role in change of water quality and ecosystem characteristics of large river systems.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.670-678
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• 2014

The purpose of this study was to find the optimal swelling method and condition for seacucumber to improve its taste and texture to accomodate the rapid increase of consumption. Another purpose was to try to determine an easy way to soak dried sea-cucumber under different conditions, and identify the influence of swelling time on the texture of sea-cucumber, in order to reduce preparation time and provide basic data for easy handling. After boiling or steaming for six different periods including 5, 15, 30 and 60 minutes the texture of the sea-cucumbers were compared, For the additive test, the sea-cucumbers were boiling for 30 minutes period with 4 different additives and the textures were compared, Since the texture is an important characteristic of sea-cucumber, there are many variables that affect this property including the, drying and preservation methods. This study provides basic understanding of the influence of the heating method, time and temperature on the swelling of sea-cucumber for handy use at processing sites.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.49-60
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• 1996

In order to evaluate soil factors affecting the growth of Italian poplar, 23 areas planted with Italian poplar were surveyed. These 23 areas were classified into 3 categories, river-side, fallow-land and hill-side. The growth performance and soil factors for each area were investigated. The growth of Italian poplar at river-side was shown to be superior to that of fallow-land and fill-side. The rates of growth for fallow-land and hill-side are decreased by 8% and 21% compared to those of river-side, respectively. This suggests that plantation of Italian poplar at hill-side would not be profitable. Soil conditions of high productive area appeared liquid phase 20%, porosity 45%, water holding capacity 35 - 40%, soil hardness $1kg/cm^3$. pH 6 and rich in organic matter and total nitrogen. The results of factor analysis for soil factors affecting to Italian poplar growth that showed eigenvalue over 1 and communality value over 70% explained factor 1 : liquid phase, porosity and water holding capacity, factor 2 : pH and calcium, and factor 3 : soil hardness. This suggests that physical characteristics of soil is more important than chemical characteristics for Italian poplar growth. Multiregerssion analysis was conducted between diameter growth and soil hardness, liquid phase and calcium. The t-values for each independent variables showed significance at 1 - 10% level, but water holding capacity and pH are not significant. It is supposed that sites suitable to Italian poplar were alluvial plain of sandy loam or part of banking soil, well-ventilating soil, lower soil hardness, apposite soil moisture absorbing with about 100cm of ground water level, plentiful organic matters and total nitrogen and little acidity soil.

• Journal of the Korean Child Neurology Society
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• v.26 no.4
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• pp.205-209
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• 2018

Purpose: Several studies have shown that magnesium plays an important role in modulating N-methyl-D-aspartate (NMDA)-related seizures by blocking NMDA ion channel receptors. Clinicians usually measure total serum magnesium levels instead of biologically active ionized magnesium levels. We compared the serum ionized magnesium ($iMg^{2+}$) level between epileptic children with and without a history of fever-triggered seizure (FTS). Methods: All epileptic children who visited the outpatient clinic or pediatric emergency department at Korea University Guro Hospital between January 2015 and July 2017 were included. Only epileptic children aged 1-8 years who were newly diagnosed within 2 years were included. Results: There were 12 children with FTS and 16 without FTS. Median serum $iMg^{2+}$ level was 0.93 (0.85-1.14, quartile) mEq/L. Serum $iMg^{2+}$ level was significantly lower in epileptic children with FTS (0.86 mEq/L) compared to those without FTS (1.10 mEq/L) (P=0.005). No difference was noted in clinical variables between the two groups. Lower serum $iMg^{2+}$ level significantly increased the risk of having FTS in epileptic children based on multivariable logistic regression analysis (odds ratio [OR]=0.028). Conclusion: Serum $iMg^{2+}$ level was significantly lower in epileptic children with FTS than in those without FTS. Measurement of biologically active serum $iMg^{2+}$ level could be considered in epileptic children with recurrent FTS. A large-scale prospective study is warranted.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.4
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• pp.195-209
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• 2021

According to the 2019-2020 social media usage survey conducted by the Seoul e-commerce center, 5 out of 10 consumers have experienced shopping through social media. The cost of traditional advertising media has been reduced and advertising spending on social media has risen by 74%, indicating that social media is becoming a more important marketing element. While the number of users of social media has increased and corporate marketing activities have increased accordingly, research has been conducted in various aspects of marketing such as user motivation for social media, satisfaction, and purchase intention. There was no subdivided study on the differences in the social media usage frequency of consumers in actual purchasing behavior. This study attempted to identify differences in consumer characteristics by cluster in the agrifood purchase situation by grouping them by type according to the frequency of use of social media for consumers who purchase agri-food online. Product involvement, product need, and online purchase channel Consumer characteristics such as demographic distribution, perceived risk, and eating and lifestyle in each cluster were checked for the three agrifood purchase situations including choice, and types for each cluster were presented. To this end, questionnaire data on the frequency of social media use and online agrifood purchase behavior were collected from 245 consumers, and the validity of the measurement variables was secured through factor analysis and reliability analysis. As a result of cluster analysis according to the frequency of social media use, it was divided into three clusters. The first cluster was a group that mainly used open social media, and the second cluster was a group that used both open and closed social media and online shopping malls; The third cluster was a group with low online media usage overall, and the characteristics of each cluster appeared. Through regression analysis, the effect on product involvement, product need, and purchase channel selection when purchasing agri-food online through each of the three clusters was confirmed through regression analysis. As a result of the regression analysis, the characteristic of cluster 1 in the situation of purchasing agri-food online is a male in his 30s living in a rural area who has no reluctance to purchase agri-food on social media or online shopping malls. The characteristics of cluster 2 are mainly consumers who are interested in purchasing health food, and the consumer characteristics are represented. In the case of cluster 3, when purchasing products online, they purchase after considering quality and price a lot, and the consumer characteristics are represented as people who are more confident in purchasing offline than online. Through this study, it is judged that by identifying the differences in consumer characteristics that appear in the agri-food purchase situation according to the frequency of social media use, it can be helpful in strategic judgments in marketing practice on social media customer targeting and customer segmentation.