• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.268-277
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• 2022

In this study, each component of flow noise source of underwater propeller installed to the scale model of the KVLCC2 is investigated and the effect of each noise source on underwater-radiated noise is quantitatively analyzed. The computation domain is set to be the same as the test section of the large cavitation tunnel in the Korea Research Institute of Ship and Ocean Engineering. First, for the high-resolution computation of flow field which is noise source region, the incompressible multiphase Delayed Detached Eddy Simulation is performed. Based on flow simulation results, the Ffowcs Williams and Hawkings integral equation is used to predict underwater-radiated noise and its validity is confirmed through the comparison with the tunnel experiment result. For the quantitative comparison on the contribution of each noise source, the spectral levels of sound pressure and power levels predicted using propeller tip-vortex cavitation, blade surface and rudder surface as the integral region of noise sources are investigated. It is confirmed that the cavitation which is monopole noise source significantly contributed to the underwater-radiated noise than propeller blades and rudder which is dipole noise source, and the rudder have more contribution than propeller blades due to the influence of the propeller wake.

• Journal of Intelligence and Information Systems
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• v.29 no.4
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• pp.325-345
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• 2023

In the rapidly evolving domain of e-commerce, our study presents a cohesive approach to enhance customer satisfaction prediction from online reviews, aligning methodological innovation with practical insights. We integrate the RFE-SHAP feature selection with LDA topic modeling to streamline predictive analytics in e-commerce. This integration facilitates the identification of key features-specifically, narrowing down from an initial set of 28 to an optimal subset of 14 features for the Random Forest algorithm. Our approach strategically mitigates the common issue of overfitting in models with an excess of features, leading to an improved accuracy rate of 84% in our Random Forest model. Central to our analysis is the understanding that certain aspects in review content, such as quality, fit, and durability, play a pivotal role in influencing customer satisfaction, especially in the clothing sector. We delve into explaining how each of these selected features impacts customer satisfaction, providing a comprehensive view of the elements most appreciated by customers. Our research makes significant contributions in two key areas. First, it enhances predictive modeling within the realm of e-commerce analytics by introducing a streamlined, feature-centric approach. This refinement in methodology not only bolsters the accuracy of customer satisfaction predictions but also sets a new standard for handling feature selection in predictive models. Second, the study provides actionable insights for e-commerce platforms, especially those in the clothing sector. By highlighting which aspects of customer reviews-like quality, fit, and durability-most influence satisfaction, we offer a strategic direction for businesses to tailor their products and services.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.843-855
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• 2006

The purpose of this study was to understand the substance of the reflective inquiry of students and obtain educational suggestion to the inquiry class for the promotion of the reflective inquiry, by checking out which characteristics the reflective inquiry showed according to the modes of interaction of small group in highschool earth science inquiry class. The result of study is shown as follows. At the stage of developmentand conclusion, the reflective inquiry relating the task context to data context was often appeared on the group of the modes of comfort interaction, but it was very rare on the group of modes of confrontation interaction. And the reflective inquiry scale value of the latter was two times lower than the former, The comfort group showed much more reflective inquiry statements quantitatively and performed much more meaningful reflective inquiry relating the task context to the data context. The heterogeneous group in the inquiry ability and the cognitive style showed confrontation interaction modes in the affective domain, having the most negative influence on the reflective inquiry. The homogeneous group both in the cognitive style and the inquiry ability showed the comfort interaction mode, having positive int1uence on the reflective inquiry.

• Information Systems Review
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• v.22 no.2
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• pp.101-120
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• 2020

This study investigates the effects of privacy psychological characteristics of B2C logistics services users on their willingness to comply with their logistics companies' information protection policy. Using cognitive valence theory as a theoretical framework, this study proposes a research model to examine the relationships between users' logistics security knowledge, privacy trust, privacy risk, privacy concern, and their willingness of information protection policy compliance. To test the proposed model, we conducted a survey from actual users of logistics services and collected valid 151 samples. We analyzed the data using a structural equation modeling software. The empirical results show that logistics security knowledge positively affects privacy trust; privacy concern positively influences privacy risk; privacy trust, privacy risk, and privacy concern positively influence behavioral willingness of compliance. However, logistics security knowledge does not affect behavioral willingness of compliance. The results of the study provide several contributions to the literature of B2C logistics services domain and managerial implications to logistics services companies.

• Radiation Oncology Journal
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• v.20 no.4
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• pp.359-366
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• 2002

Purpose : The purpose of the present study was to analyze and evaluate prior studies published in Korea on the cancer-related quality of life, in order to make recommendations for further research. Materials and Methods : A total of 31 studies were selected from three different databases. The selected studies were analyzed according to 11 criteria, such as site of cancer, domain, independent variable, research design, self/proxy rating, single/battery instrument, translation/back translation, reliability, validity, scoring, and findings. Results : Of the 31 studies, approximately half of them were conducted using a mixed cancer group of patients. Many of the studies asserted that the concept of quality of life had a multidimensional attribute. Approximately 30% were longitudinal design studies giving information about the changes in quality of life. In all studies, except one, patients directly rated their level of quality of life. With respect to the questionnaires used for measuring the quality of life, most studies did not consider whether or not their reliability and validity had been established. In addition, when using questionnaires developed in other languages, no studies employed a translation/ back-translation technique. All studies used sum or total scoring methods when calculating the level of quality of life. The types of variables tested for their influence on qualify of life were quite limited. Conclusion : It is recommended that longitudinal design studies be peformed, using methods of data collection whose validity and reliability has been confirmed, and that studies be conducted to identify new variables having an influence on the quality of life.

• Asia pacific journal of information systems
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• v.21 no.2
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• pp.89-116
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• 2011

In collaborative tagging systems such as Delicious.com and Flickr.com, users assign keywords or tags to their uploaded resources, such as bookmarks and pictures, for their future use or sharing purposes. The collection of resources and tags generated by a user is called a personomy, and the collection of all personomies constitutes the folksonomy. The most significant need of the folksonomy users Is to efficiently find useful resources or experts on specific topics. An excellent ranking algorithm would assign higher ranking to more useful resources or experts. What resources are considered useful In a folksonomic system? Does a standard superior to frequency or freshness exist? The resource recommended by more users with mere expertise should be worthy of attention. This ranking paradigm can be implemented through a graph-based ranking algorithm. Two well-known representatives of such a paradigm are Page Rank by Google and HITS(Hypertext Induced Topic Selection) by Kleinberg. Both Page Rank and HITS assign a higher evaluation score to pages linked to more higher-scored pages. HITS differs from PageRank in that it utilizes two kinds of scores: authority and hub scores. The ranking objects of these pages are limited to Web pages, whereas the ranking objects of a folksonomic system are somewhat heterogeneous(i.e., users, resources, and tags). Therefore, uniform application of the voting notion of PageRank and HITS based on the links to a folksonomy would be unreasonable, In a folksonomic system, each link corresponding to a property can have an opposite direction, depending on whether the property is an active or a passive voice. The current research stems from the Idea that a graph-based ranking algorithm could be applied to the folksonomic system using the concept of mutual Interactions between entitles, rather than the voting notion of PageRank or HITS. The concept of mutual interactions, proposed for ranking the Semantic Web resources, enables the calculation of importance scores of various resources unaffected by link directions. The weights of a property representing the mutual interaction between classes are assigned depending on the relative significance of the property to the resource importance of each class. This class-oriented approach is based on the fact that, in the Semantic Web, there are many heterogeneous classes; thus, applying a different appraisal standard for each class is more reasonable. This is similar to the evaluation method of humans, where different items are assigned specific weights, which are then summed up to determine the weighted average. We can check for missing properties more easily with this approach than with other predicate-oriented approaches. A user of a tagging system usually assigns more than one tags to the same resource, and there can be more than one tags with the same subjectivity and objectivity. In the case that many users assign similar tags to the same resource, grading the users differently depending on the assignment order becomes necessary. This idea comes from the studies in psychology wherein expertise involves the ability to select the most relevant information for achieving a goal. An expert should be someone who not only has a large collection of documents annotated with a particular tag, but also tends to add documents of high quality to his/her collections. Such documents are identified by the number, as well as the expertise, of users who have the same documents in their collections. In other words, there is a relationship of mutual reinforcement between the expertise of a user and the quality of a document. In addition, there is a need to rank entities related more closely to a certain entity. Considering the property of social media that ensures the popularity of a topic is temporary, recent data should have more weight than old data. We propose a comprehensive folksonomy ranking framework in which all these considerations are dealt with and that can be easily customized to each folksonomy site for ranking purposes. To examine the validity of our ranking algorithm and show the mechanism of adjusting property, time, and expertise weights, we first use a dataset designed for analyzing the effect of each ranking factor independently. We then show the ranking results of a real folksonomy site, with the ranking factors combined. Because the ground truth of a given dataset is not known when it comes to ranking, we inject simulated data whose ranking results can be predicted into the real dataset and compare the ranking results of our algorithm with that of a previous HITS-based algorithm. Our semantic ranking algorithm based on the concept of mutual interaction seems to be preferable to the HITS-based algorithm as a flexible folksonomy ranking framework. Some concrete points of difference are as follows. First, with the time concept applied to the property weights, our algorithm shows superior performance in lowering the scores of older data and raising the scores of newer data. Second, applying the time concept to the expertise weights, as well as to the property weights, our algorithm controls the conflicting influence of expertise weights and enhances overall consistency of time-valued ranking. The expertise weights of the previous study can act as an obstacle to the time-valued ranking because the number of followers increases as time goes on. Third, many new properties and classes can be included in our framework. The previous HITS-based algorithm, based on the voting notion, loses ground in the situation where the domain consists of more than two classes, or where other important properties, such as "sent through twitter" or "registered as a friend," are added to the domain. Forth, there is a big difference in the calculation time and memory use between the two kinds of algorithms. While the matrix multiplication of two matrices, has to be executed twice for the previous HITS-based algorithm, this is unnecessary with our algorithm. In our ranking framework, various folksonomy ranking policies can be expressed with the ranking factors combined and our approach can work, even if the folksonomy site is not implemented with Semantic Web languages. Above all, the time weight proposed in this paper will be applicable to various domains, including social media, where time value is considered important.

• Journal of Hospice and Palliative Care
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• v.19 no.1
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• pp.61-69
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• 2016

Purpose: It is important to alleviate care burden for terminal cancer patients and their families. This study investigated the factors associated with care burden among family caregivers (FCs) of terminally ill cancer patients. Methods: We analyzed data from 289 FCs of terminal cancer patients who were admitted to palliative care units of seven medical centers in Korea. Care burden was assessed using the Korean version of Caregiver Reaction Assessment (CRA) scale which comprises five domains. A multivariate logistic regression model with stepwise variable selection was used to identify factors associated with care burden. Results: Diverse associating factors were identified in each CRA domain. Emotional factors had broad influence on care burden. FCs with emotional distress were more likely to experience changes to their daily routine (adjusted odds ratio (aOR), 2.54; 95% confidence interval (CI), 1.29~5.02), lack of family support (aOR, 2.27; 95% CI, 1.04~4.97) and health issues (aOR, 5.44; 2.50~11.88). Family functionality clearly reflected a lack of support, and severe family dysfunction was linked to financial issues as well. FCs without religion or comorbid conditions felt more burdened. The caregiving duration and daily caregiving hours significantly predicted FCs' lifestyle changes and physical burden. FCs who were employed, had weak social support or could not visit frequently, had a low self-esteem. Conclusion: This study indicates that it is helpful to understand FCs' emotional status and family functions to assess their care burden. Thus, efforts are needed to lessen their financial burden through social support systems.

• Journal of the Korean earth science society
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• v.22 no.5
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• pp.377-387
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• 2001

In order to elucidate sedimentation processes and depositional environments in transitional area between continental shelf and coastal zone, sedimentologic study has been done with 84 surface sediments sampled in nearshore/offshore off the mid-western coast of the Korean Peninsula for 3 years (1996${\sim}$1999). The surface sediment can be classified into 4 facies (gravelly sand, sand, silty sand and sandy silt). Mean grain size, sorting, skewenss and kurtosis varies -0.39${\sim}7.82{\Phi}$, 0.36${\sim}4.68{\Phi}$, -0.38${\sim}$0.86, -1.56${\sim}$3.43, respectively. The textural parameters show a finer-grained and poorly-sorted trend shoreward, northward and southward from the central part of the study area. The positively-skewed distribution and relationship of each textural parameters indicate a tide-dominated depositional environment. According to C/M diagram, there are 3 different domains (mode A, B, C) of sediment transport mode. The northern part is characterized by bedload transport (mode A) and represents co-influence of wave and tide, whereas domain C in the southern part is controlled by uniform suspension transport (mode C), correlating with sandy-silt area. In the broad middle area, transport processes are complex (the mixture of bedload, graded suspension and uniform suspension; mode B). Hence, the subdivision depositional environments of this study area may be classified by 3 depositional environments dependent on the interplay of sediment supplies from river, relict sediments and hydrologic conditions. In results, the nearshore and offshore areas are thus characterized as a mixing zone between coastal terrigenous sediments and relict sediments in the continental shelf by complex processes (tide, wave and river flow). These sedimentation processes play an important role in producing distinct sedimentologic features in the transitional zone linking coastal and shelfal areas.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.176-184
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• 2017

Objectives : Middle aged women with depression often experience hot flush symptoms. It is still unclear about the association between depression and hot flush symptoms. Therefore, we investigated hormonal profile, functional somatic symptoms, coping styles and attitude for menopause between depressed women with hot flush and those without hot flush. Methods : This study included 33 depressed patients with hot flush symptoms and 33 depressed patients without hot flush symptoms. Hot flush was confirmed through prospective daily symptom ratings for a week. Subjects' coping styles were assessed by the stress coping checklist. Somatic symptoms were assessed by the Patient Health Questionnaire-15(PHQ-15). Sex hormonal levels were assayed by a radioimmunoassay. The Brief World Health Organization Quality of Life Assessment Instrument(WHOQOL-BREF) was used to evaluate quality of life. Results : In coping style, depressed women with hot flush symptoms used less 'problem-centered coping'($13.15{\pm}3.17$) and 'search for social support'($11.83{\pm}2.84$) than those without hot flush symptoms($15.17{\pm}3.1$, p=0.028 ; $14.25{\pm}3.22$, p=0.009 ; respectively). Depressed women with hot flush symptoms showed more negative attitude toward post-menopause, but its statistical significance was marginally insufficient(p=0.059). We did not find any group differences in sex hormonal levels and somatic complaints assessed by the PHQ-15. The score of social relationship domain of WHOQOL-BREF was significantly lower in subjects with hot flush symptoms($8.62{\pm}2.04$) than subjects without hot flush symptoms($9.71{\pm}1.65$ ; p=0.044). Conclusions : Among middle aged women with depression, the manifestation of hot flush symptoms was associated with coping styles and attitude for menopausal transition. Hot flush symptoms in depressed women negatively influence quality of life, so clinicians actively perform therapeutic approach in case of depressed patients with hot flush symptoms. In case of depressed patients who present hot flushes, cognitive behavior therapy or stress management might be an effective treatment option in company with antidepressants or hormonal treatment. Later, longitudinal study will be needed to evaluate risk factor, cause and effect associated with hot flush and depression.

• Journal of Korean Academy of Nursing
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• v.27 no.2
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• pp.411-422
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• 1997

The purpose of this study is twofold : (i) to investigate how much effort the married couples are making for the good health of both the pregnant woman and her unborn child from the time of their marriage to and during the period of conception : and (ii) to comprehensive investigate socio-cultural back-grounds which affect prenatal effort. Result of this study provide a basis for the prenatal care program which will be appropriate to our culture. This study has been done by the ethnographic research method. The subjects of this study are 53 people in all consisting of 33 pregnant women and 20 husbands. In order to investigate socio-cultural factors which influence Taegyo, producers of Taegyo music were interviewed. In addition the researcher surveyed the markets of Taegyo music, participated in special courses of prenatal education, analyzed the content of the books and periodicals dealing with Taegyo, and collected the concept of Taegyo distributed by the mass media. The full-fledged study continued for eight months from February to August.1996. The data were analyzed as soon as they were collected. Spradly's(1979, 1980) developmental, sequential method of domain analysis. taxonomic analysis, componential analysis, and theme analysis in this order was adopted as the procedure of analyzing the data. To obtain the exactness of study, Sandelowski's (1986) four criteria, that is, Credibility, Fittingness, Auditability, and Confirmability were applied to all stages of data collection, data analysis, the interpretation of the result, and the description of the result. The following are the result : 1. The couples' Taegyo at the stage of preconception was related to their physical, psychological, spiritual conditions under which a healthy baby will be born. Specific methods they prefer are : "the choice of one's spouse." "physical check-up," "physical good health, " "praying, " and so on. 2. When the marriod couple have sex in order to conceive, their Taegyo was related to the imposition of their physical, psychological, and environmental conditions. Specific methods they prefer are : "having sex at specific time, " "having sex in nice place." "to purify their minds while having sex," and so on. 3. The married couples' Taegyo while they are in pregnancy was related to the imposition of their physical. psychological, emotionmental. environmental, social and spiritual conditions. Specific methods they prefer are : "listening to music. " "reading," "looking at beautiful things only," "to avoid looking at or listening to bad things." "to eat food in good shape, " "to avoid drugs," "eating Korean herbal medicine." "sexual abstinence," "to avoid dangerous places," "to keep emotional tranquility," "moderate exercises and rest." "leading a pure life." "praying." "being aware of their words and behavior." "for the couple to keep a good relationship." "interaction with their unborn child," "to support Taegyo for pregnant women," and so on. 4. The married couple put Taegyo into practice on the basis of the following principles : the principle of respecting an unborn child, the principle of forming a good disposition. the principle of top-down parental love, the principle of synergy between a pregnant woman and her unborn child, the principle of expecting a good child, the principle of forming a good habit, and the principle of acquiring a parental role. 5. The practice of Taegyo is influenced by such factors as the married couple, the supporting system, and the mass media. As the husband -and-wife factor, their information of Taegyo, the degree of importance is assigned to their characters, their time to spare, their healthiness, the age of pregnant woman, their conception plan, their religion, their belief of the Taegyo effects, and the birth of a baby in this order. The factor of the supporting system consists of her husband's support, her family support, and her neighbor's support. The mass media factors include the broadcasting media, books specialized in Taegyo, periodicals for pregnant women, booklets for advertizing powdered milk, Taegyo music of record manufacturing companies, and the teaching materials for gifted children. Among these the mass media is especially taking advantage of Taegyo as its main source of economic profits are leading the public behavior pattern to a prodigal one. Taegyo is a self-control behavior which requires practice for the following : the physical and psychological good health of the pregnant woman and her unborn child, the development of the unborn child's good character, the development of the unborn child's intelligence and talents, the expectation of the unborn child's good features. shape a good habit, the expectation of the unborn child's bright future, and the learning of a parental role, the expectation of male birth. Above all it is a type of our good cultural tradition which pursues a value higher than the one that the prenatal care does. The principles of pregnancy care inherent in the habit of Taegyo will provide us a guideline for the development of the prenatal care.