• Journal of Preventive Medicine and Public Health
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• v.41 no.3
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• pp.181-185
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• 2008

Objectives : This study was performed to evaluate the reproducibility of a questionnaire concerned with reproductive history and to ascertain which characteristics of the subjects (age, the visit-revisit intervals, education and chronic disease) are associated with good reliability in the Korean Multi-Center Cancer Cohort (KMCC) study. Materials and Methods: A total of 19,688 participants were enrolled between 1993 and 2004. Among them, we selected 386 participants who were aged 40 or more and who re-visited within 8 years after the first visit. Reliability was measured by the percent agreement according to error range for the continuous variables and the percent agreement and kappa statistics for the categorical variables. Results : The pregnancy histories were reliable (kappa=0.67) and the reasons for being menopausal among the postmenopausal women were also reliable (kappa=0.92). The percent agreement of the breast-feeding history was high (96.1%), although the kappa statistic was low. For the continuous variables, when the error range of one variable was considered to be reliable, the percent agreement of the age at menarche and the age at the first full term pregnancy was good (69.4% and 83.6%), whereas that of the age at menopause was low (51.5%). The factors associated with high reliability were a younger age, the presence of chronic disease and a short visit-revisit time interval. Conclusions : The agreements for parity, the reasons for menopause, and the breastfeeding history in the reproductive history questionnaire used in the KMCC were relatively good. The questionnaire for the menarche age and the menopausal age might have lower reliability due to the difference between Korean age and American age. To obtain reliable information, more attention should be given to the items in questionnaire-based surveys, and especially for surveying old-aged women.

• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.128-138
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• 2007

At low in-situ stress, the continuity and distribution of natural fractures in rock mass predominantly control the failure processes. However at high in-situ stress, the failure process are affected and eventually dominated by stress-induced fractures preferentially growing parallel to the excavation boundary. This fracturing is often observed in brittle type of failure such as slabbing or spatting. Recent studies on the stress- or excavation-induced damage of rock revealed its importance especially in a highly stressed regime. In order to evaluate the brittle failure around a deep underground opening, physical model experiments were carried out. For the experiments a new tue triaxial testing system was made. According to visual observation and acoustic emission detection, brittle failure grades were classified under three categories. The test results indicate that where higher horizontal stress, acting perpendicular $(S_{H2})$ and parallel $(S_{H1})$ to the axis of the tunnel respectively, were applied, the failure grade at a constant vertical stress level (Sy) was lowered. The failure initiation stress was also increased with the increasing $S_{H1}\;and\;S_{H2}$. From the multi-variable regression on failure initiation stress and true triaxial stress conditions, $f(S_v,\;S_{H1},\;S_{H2})$ was proposed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.6
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• pp.385-391
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• 2022

This paper presents to develop a path planning algorithm combining gradient descent-based path planning (GBPP) and particle swarm optimization (PSO) for considering prohibited flight areas, terrain information, and characteristics of fixed-wing unmmaned aerial vehicle (UAV) in 3D space. Path can be generated fast using GBPP, but it is often happened that an unsafe path can be generated by converging to a local minimum depending on the initial path. Bio-inspired swarm intelligence algorithms, such as Genetic algorithm (GA) and PSO, can avoid the local minima problem by sampling several paths. However, if the number of optimal variable increases due to an increase in the number of UAVs and waypoints, it requires heavy computation time and efforts due to increasing the number of particles accordingly. To solve the disadvantages of the two algorithms, hierarchical path planning algorithm associated with hierarchical particle swarm optimization (HPSO) is developed by defining the initial path, which is the input of GBPP, as two variables including particles variables. Feasibility of the proposed algorithm is verified by software-in-the-loop simulation (SILS) of flight control computer (FCC) for UAVs.

• Korean Journal of Psychosomatic Medicine
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• v.28 no.1
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• pp.20-28
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• 2020

Objectives : The aim of this study was to compare psychosocial characteristics of the functional gastrointestinal disorders FGID group, non-FGID group, and control group and determine factors affecting the QOL of patients with FGID. Methods : 135 patients diagnosed with FGID were selected. 79 adults had no observable symptoms of FGID (control group) and 88 adults showed symptoms of FGID (non-FGID group). Demographic factors were investigated. The Korean-Beck Depression Inventory-II, Korean-Beck Anxiety Inventory, Korean-Childhood Trauma Questionnaire, Multidimensional Scale of Perceived Social Support, Connor-Davidson Resilience Scale, Patient Health Questionnaire-15 and WHO Quality of Life Assessment Instrument Brief Form were used to assess psychosocial factors. A one-way ANOVA was used to compare differences among groups. Pearson correlation test was performed to analyze the correlation of psychosocial factors and QOL of the FGID group. Further, a hierarchical regression analysis was conducted to determine factors affecting the QOL of the FGID group. Results : Between-group differences were not significant in demographic characteristics. Depression (F=48.75, p<0.001), anxiety (F=14.48, p<0.001), somatization (F=24.42, p<0.001) and childhood trauma (F=12.71, p<0.001) were significantly higher in FGID group than in other groups. Social support (F=39.95, p<0.001) and resilience (F=17.51, p<0.001) were significantly lower in FGID group than in other groups. Resilience (β=0.373, p<0.01) was the most important explanatory variable. The explained variance was 47.2%. Conclusions : Significantly more symptoms of depression, anxiety, childhood trauma, and somatization were observed for the FGID group. This group also had less social support, resilience, and quality of life than the non-FGID and control groups. The key factor for quality of life of the FGID group was resilience.

• Asia Marketing Journal
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• v.14 no.2
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• pp.65-96
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• 2012

Brand has received much attention from considerable marketing research. When consumers consume product or services, they are exposed to a lot of brand related stimuli. These contain brand personality, brand experience, brand identity, brand communications and so on. A special kind of new crisis occasionally confronting companies' brand management today is the brand related rumor. An important influence on consumers' purchase decision making is the word-of-mouth spread by other consumers and most decisions are influenced by other's recommendations. In light of this influence, firms have reasonable reason to study and understand consumer-to-consumer communication such as brand rumor. The importance of brand rumor to marketers is increasing as the number of internet user and SNS(social network service) site grows. Due to the development of internet technology, people can spread rumors without the limitation of time, space and place. However relatively few studies have been published in marketing journals and little is known about brand rumors in the marketplace. The study of rumor has a long history in all major social science. But very few studies have dealt with the antecedents and consequences of any kind of brand rumor. Rumor has been generally described as a story or statement in general circulation without proper confirmation or certainty as to fact. And it also can be defined as an unconfirmed proposition, passed along from people to people. Rosnow(1991) claimed that rumors were transmitted because people needed to explain ambiguous and uncertain events and talking about them reduced associated anxiety. Especially negative rumors are believed to have the potential to devastate a company's reputation and relations with customers. From the perspective of marketer, negative rumors are considered harmful and extremely difficult to control in general. It is becoming a threat to a company's sustainability and sometimes leads to negative brand image and loss of customers. Thus there is a growing concern that these negative rumors can damage brands' reputations and lead them to financial disaster too. In this study we aimed to distinguish antecedents of brand rumor transmission and investigate the effects of brand rumor characteristics on rumor spread intention. We also found key components in personal acceptance of brand rumor. In contextualist perspective, we tried to unify the traditional psychological and sociological views. In this unified research approach we defined brand rumor's characteristics based on five major variables that had been found to influence the process of rumor spread intention. The five factors of usefulness, source credibility, message credibility, worry, and vividness, encompass multi level elements of brand rumor. We also selected product involvement as a control variable. To perform the empirical research, imaginary Korean 'Kimch' brand and related contamination rumor was created and proposed. Questionnaires were collected from 178 Korean samples. Data were collected from college students who have been experienced the focal product. College students were regarded as good subjects because they have a tendency to express their opinions in detail. PLS(partial least square) method was adopted to analyze the relations between variables in the equation model. The most widely adopted causal modeling method is LISREL. However it is poorly suited to deal with relatively small data samples and can yield not proper solutions in some cases. PLS has been developed to avoid some of these limitations and provide more reliable results. To test the reliability using SPSS 16 s/w, Cronbach alpha was examined and all the values were appropriate showing alpha values between .802 and .953. Subsequently, confirmatory factor analysis was conducted successfully. And structural equation modeling has been used to analyze the research model using smartPLS(ver. 2.0) s/w. Overall, R² of adoption of rumor is .476 and R² of intention of rumor transmission is .218. The overall model showed a satisfactory fit. The empirical results can be summarized as follows. According to the results, the variables of brand rumor characteristic such as source credibility, message credibility, worry, and vividness affect argument strength of rumor. And argument strength of rumor also affects rumor intention. On the other hand, the relationship between perceived usefulness and argument strength of rumor is not significant. The moderating effect of product involvement on the relations between argument strength of rumor and rumor W.O.M intention is not supported neither. Consequently this study suggests some managerial and academic implications. We consider some implications for corporate crisis management planning, PR and brand management. This results show marketers that rumor is a critical factor for managing strong brand assets. Also for researchers, brand rumor should become an important thesis of their interests to understand the relationship between consumer and brand. Recently many brand managers and marketers have focused on the short-term view. They just focused on strengthen the positive brand image. According to this study we suggested that effective brand management requires managing negative brand rumors with a long-term view of marketing decisions.