• Communications for Statistical Applications and Methods
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• v.31 no.3
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• pp.323-336
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• 2024

The accurate forecasting of insurance claims is a critical component for insurers' risk management decisions. Hierarchical Bayesian parametric (BP) models can be used for health insurance claims forecasting, but they are unsatisfactory to describe the claims distribution. Therefore, Bayesian nonparametric (BNP) models can be a more suitable alternative to deal with the complex characteristics of the health insurance claims distribution, including heavy tails, skewness, and multimodality. In this study, we apply both a BP model and a BNP model to predict group health claims using simulated and real-world data for a private life insurer in Indonesia. The findings show that the BNP model outperforms the BP model in terms of claims prediction accuracy. Furthermore, our analysis highlights the flexibility and robustness of BNP models in handling diverse data structures in health insurance claims.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.76-94
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• 2008

This paper investigates performance of the Markowitz's portfolio selection model with applications to Korean stock market. We choose Samsung-Group-Funds and KOSPI index for performance comparison with the Markowitz's portfolio selection model. For the most recent one and a half year period between March 2007 and September 2008, KOSPI index almost remains the same with only 0.1% change, Samsung-Group-Funds shows 20.54% return, and Markowitz's model, which is composed of the same 17 Samsung group stocks, reaches 52% return. We perform sensitivity analysis on the duration of financial data and the period of portfolio change in order to maximize the return of portfolio. In conclusion, according to our empirical research results with Samsung-Group-Funds, investment by Markowitz's model, which periodically changes portfolio by using nonlinear programming with only financial data, outperforms investment by the fund manager who possesses rich experiences on stock trading and actively changes portfolio based on minute-by-minute market news and business information.

• School Mathematics
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• v.5 no.3
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• pp.361-384
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• 2003

The purpose of this study was to investigate students' problem solving process based on the model of IDEAL if they learn to solve word problems of simultaneous linear equations through structure-representation instruction. The problem solving model of IDEAL is followed by stages; identifying problems(I), defining problems(D), exploring alternative approaches(E), acting on a plan(A). 160 second-grade students of middle schools participated in a study was classified into those of (a) a control group receiving no explicit instruction of structure-representation in word problem solving, and (b) a group receiving structure-representation instruction followed by IDEAL. As a result of this study, a structure-representation instruction improved word-problem solving performance and the students taught by the structure-representation approach discriminate more sharply equivalent problem, isomorphic problem and similar problem than the students of a control group. Also, students of the group instructed by structure-representation approach have less errors in understanding contexts and using data, in transferring mathematical symbol from internal learning relation of word problem and in setting up an equation than the students of a control group. Especially, this study shows that the model of direct transformation and the model of structure-schema in students' problem solving process of I and D stages.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.10-14
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• 2008

Computer-animated crowd scenes are often observed in computer games and feature films. The common way to model locomotion of large human crowds is to employ agent based methods where the behavior of each person is independently modeled. But for large crowds, it is difficult for a user to control all the individuals using individual behavior model. Instead, crowd behaviors can be controlled more intuitively at the group level than at the individual level. In this paper, we present the group force field model to simulate path following behavior for groups. A group is a set of characters who have the same goals, i.e. the same path to follow. We also define three characteristics of grouping behavior: alignment, cohesion, and distribution. Our group force field model preserves these characteristics while avoiding collisions. By using our model, user can generate desired group behaviors from line-up behavior to lumped one.

• Journal of the Korean Society of Safety
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• v.36 no.1
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• pp.1-8
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• 2021

To simulate a process model in the field of chemical engineering, it is very important to identify the physical properties of novel materials as well as existing materials. However, it is difficult to measure the physical properties throughout a set of experiments due to the potential risk and cost. To address this, this study aims to develop a property prediction model based on the group contribution method for aromatic chemical compounds including benzene rings. The benzene rings of aromatic materials have a significant impact on their physical properties. To establish the prediction model, 42 important functional groups that determine the physical properties are considered, and the total numbers of functional groups on 147 aromatic chemical compounds are counted to prepare a dataset. Support vector regression is employed to prepare a prediction model to handle sparse and high-dimensional data. To verify the efficacy of this study, the results of this study are compared with those of previous studies. Despite the different datasets in the previous studies, the comparison indicated the enhanced performance in this study. Moreover, there are few reports on predicting the physical properties of aromatic compounds. This study can provide an effective method to estimate the physical properties of unknown chemical compounds and contribute toward reducing the experimental efforts for measuring physical properties.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.515-518
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• 2010

Horizontal forces may form a major part of the loading system for structures supported on pile groups. It is known that during a strong earthquake, the dynamic behavior of a group-pile foundation is related not only to the inertial force coming from the superstructures but also to the deformation of the surrounding ground. Therefore, it is necessary to understand the behaviors of the group-pile foundations and superstructures during major earthquakes. In this paper, numerical simulation of real-scale group-pile foundation subjected to horizontal cyclic loading is conducted by using a program named as DBLEAVES. In the analysis, nonlinear behaviors of ground and piles are described by cyclic mobility model and axial force dependent model (AFD model). The purpose of this paper is to prove availability of the analysis method by comparing numerical results and test results.

• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.226-238
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• 1998

I studied a group management model of virtual class for distance education system on the information superhighway. There are many objects and actions that need to be managed and controlled in virtual classes of a distance education model. Educators should be able to manage students' learning group and immediately be aware of who is attending and who is quitting the learning group in a virtual class. Also, students and educators in virtual classes can communicate and discuss various topics. I proposed a group management model for distance education on a network, and studied management algorithm and MIB (Management Information Base), which are required to manage virtual classes in distance education systems.

• The Korean Journal of Rehabilitation Nursing
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• v.20 no.1
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• pp.12-21
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• 2017

Purpose: This study attempts to examine the effects of a horticultural program on activities of daily living (ADL) and depression among older patients with mild dementia. Methods: This study adopted a quasi-experimental design-based nonequivalent control group pretest and posttest design, enrolling 30 older patients with mild dementia. The Korean Form of Geriatric Depression Scale was utilized, while the data was collected from the experimental group for 60 minutes, twice weekly for 6 weeks in 12 sessions. ADL and depression were assessed for both the experimental and the control group. Overall functions were assessed only for the experimental group. Results: The experimental group showed improvement in physical function, cognitive function, as well as psychological, emotional function and social function following each session (p<.001). The horticulture program was effective in both ADL ($Z^2=5.65$, p<.001) and depression (t=-5.24, p<.001). Conclusion: In this study, the horticultural therapy based on the Cox's interaction model had positive effects for older patients with mild dementia. Therefore, horticultural therapy may be commendably applied to older patients with mild dementia as a nursing intervention.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.55-59
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• 2013

Ionizing radiation causes the massive generation of reactive oxygen species, resulting in cellular and tissue damage. The present study was performed to evaluate ${\gamma}$-irradiation induced cellular damage in ICR mice. The mice were divided into four groups with ten mice in each group. Group 1 served as an unexposed control group. Groups 2, 3, and 4 were exposed to 3, 5, and 7 Gy of ${\gamma}$-radiation, respectively. Five mice per group were sacrificed 1 and 7 days after ${\gamma}$-radiation. Exposure to ${\gamma}$-irradiation resulted in hematopoietic damage in a dose-dependent manner when compared with the unexposed control group, which featured a significantly decreased spleen index. However, the exposed mice showed no significant differences in their serum AST, ALT and in the histopathological change of their liver. These results suggest that ${\gamma}$-irradiation is a good tool to prepare a hematopoietic damage model. This animal model can be employed to study the hematopoietic efficacy of biologically active compounds.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.24 no.2
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• pp.28-34
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• 2011

Background & Objectives : Allergic rhinitis is an inflammation or irritation of the mucous membranes that line the nose. Common symptoms include sneezing, a stuffy or runny nose, itchy eyes, nose and throat, and watery eyes. We aimed to determine therapeutic effects of Tribulus terrestris by observing changes of total IgE level and the scratching or rubbing around the nose behavior. Materials and Methods : Fifteen BALB/c mice were divided into three groups : AR group(allergic rhinitis elicitated), TT group(which ate herbal medicine) and AH group(which ate antihistamine). Allergic rhinitis was induced in the three groups by intraperitoneal and intranasal sensitization with 0.1% ovalbumin solution. Then Tribulus terrestris was orally administered only to the TT group of 28days, while the AH group was given antihistamine. We observed changes of total IgE level and the scratching or rubbing around the nose behavior. We used Kruskal-Wallis test statistically(p<0.05). Results : 1. Tribulus terrestris showed significantly decreased IgE level on the serum of the rat model. 2. Tribulus terrestris showed significantly decreased scratching or rubbing around the nose behaviors of the rat model. Conclusion : According to the above results, it is considered that Tribulus terrestris has an inhibitory effect on the process of allergic rhinitis and it can be used in relieving symptoms of allergic rhinitis.