• Structural Engineering and Mechanics
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• v.22 no.6
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• pp.665-683
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• 2006

The strength behaviors of Fiber Reinforced Plastics (FRP) Composites can be greatly influenced by the properties of constitutive materials, the laminate structures, and load conditions etc, accompanied by many uncertainty factors. So the reliability study on FRP is an important subject of research. Many achievements have been made in reliability studies based on the probability theory, but little has been done on the roles played by fuzzy variables. In this paper, a fuzzy reliability model for FRP laminates is established first, in which the loads are considered as random variables and the strengths as fuzzy variables. Then a numerical model is developed to assess the fuzzy reliability. The Monte Carlo simulation method is utilized to compute the reliability of laminas under the maximum stress criterion. In the second part of this paper, a generalized fuzzy reliability model (GFRM) is proposed. By virtue of the fact that there may exist a series of states between the failure state and the function state, a fuzzy assumption for the structure state together with the probabilistic assumption for strength parameters is adopted to construct the GFRM of composite materials. By defining a generalized limit state function, the problem is converted to the conventional reliability formula that enables the first-order reliability method (FORM) applicable in calculating the reliability index. Several examples are worked out to show the validity of the models and the efficiency of the methods proposed in this paper. The parameter sensitivity analysis shows that some of the mean values of the strength parameters have great influence on the laminated composites' reliability. The differences resulting from the application of different failure criteria and different fuzzy assumptions are also discussed. It is concluded that the GFRM is feasible to use, and can provide an effective and synthetic method to evaluate the reliability of a system with different types of uncertainty factors.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.487-496
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• 2016

This study aims to explore the present condition of job preparation of students in the department of physical education in depth so that convergence talents with professional physical education abilities can be trained and physical education majors can establish themselves in adverse conditions such as the reduction of the entrance quota and a lack of cases of research on job training in the departments related to physical education by the college evaluation of the Ministry of Education and to present a direction of career training. In order to analyze the relationships among sub-factors according to the level of perception of physical education-related majors, methods such as MANOVA and correspondence analysis were used. The results obtained through the research are as follows: First, it turned out that it is important to carry out career training in advance, considering physical education-related college students' aptitude and talent by grade. Second, it turned out that it is important to alleviate the problem of employment barrier in the preparation for career fast. Third, it turned out that it is important for us all to make efforts to expand the types of physical education-related employment and provide opportunities.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.23 no.2
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• pp.82-89
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• 2012

Objectives : Demands for comprehensive and intensive treatment programs for treatment of children with attention-deficit hyperactivity disorder (ADHD) who suffer from serious impairment in various psychosocial areas are increasing. The aim of this study was to evaluate the possibility of developing new types of camp programs focused on improving social adjustment of children and helping parents effectively manage their children's problem behaviors. Methods : Fifteen children diagnosed as ADHD according to Diagnostic and Statistical Manual of Mental Disorders-IV (mean age 9.5 years) and their parents participated in this program. Eight consecutive camps were held at two-week intervals, from Jun 2007 to Oct 2007 in an adolescent training center located at Chungtaesan, in Korea. Each camp program included social skills training in the classroom and outdoor activities in the forest for children, as well as parent training for mothers. In addition, after the sixth camp, we conducted one parental session for fathers and a three-day booster family camp three months later. Finally, eleven families adhered to the program. Results : All children, parents, and therapists rated questionnaires or checklists at baseline, intra-, and post-treatment. Parenting burden rated using the Parenting Stress Index showed a significant decrease, from 57.89 to 46.22 (p=.019). And, overprotection rated using the Parenting Bonding Instrument showed a significant decrease, from 16.56 to 12.44 (p=.046). However, no significant improvement in children's behavioral and emotional problems was observed. Conclusion : In this study, the consecutive ADHD family camp program was effective for empowerment of parental competency, but not for general improvement of children's behavioral and emotional symptoms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3738-3760
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• 2022

Due to increasing spectrum demand for new wireless devices applications, cooperative spectrum sensing (CSS) paradigm is the most promising solution to alleviate the spectrum shortage problem. However, in the interweave cognitive radio (CR) system, the inherent nature of CSS opens a hole to Byzantine attack, thereby resulting in a significant drop of the CSS security and efficiency. In view of this, a weighted differential sequential single symbol (WD3S) algorithm based on MATLAB platform is developed to accurately identify malicious users (MUs) and benefit useful sensing information from their malicious reports in this paper. In order to achieve this, a dynamic Byzantine attack model is proposed to describe malicious behaviors for MUs in an interweave CR system. On the basis of this, a method of data transmission consistency verification is formulated to evaluate the global decision's correctness and update the trust value (TrV) of secondary users (SUs), thereby accurately identifying MUs. Then, we innovatively reuse malicious sensing information from MUs by the weight allocation scheme. In addition, considering a high spectrum usage of primary network, a sequential and differential reporting way based on a single symbol is also proposed in the process of the sensing information submission. Finally, under various Byzantine attack types, we provide in-depth simulations to demonstrate the efficiency and security of the proposed WD3S.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.413-415
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• 2022

Since human joints can be used as useful information for analyzing human behavior as a component of the human body, many studies have been conducted on human action recognition using joint information. However, it is a very complex problem to recognize human action that changes every moment using only each independent joint information. Therefore, an additional information extraction method to be used for learning and an algorithm that considers the current state based on the past state are needed. In this paper, we propose a human action recognition technique considering the positional relationship of connected joints and the change of the position of each joint over time. Using the pre-trained joint extraction model, position information of each joint is obtained, and bone information is extracted using the difference vector between the connected joints. In addition, a simplified neural network is constructed according to the two types of inputs, and spatio-temporal features are extracted by adding LSTM. As a result of the experiment using a dataset consisting of 9 behaviors, it was confirmed that when the action recognition accuracy was measured considering the temporal and spatial relationship features of each joint, it showed superior performance compared to the result using only single joint information.

• Journal of Korea Entertainment Industry Association
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• v.5 no.2
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• pp.77-86
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• 2011

This paper is aimed at analyzing the relationship between users' actions in relation to a SNG (Social Network Game), which mainly targets communities, and the motivations that give rise to such selective actions. The subjects of existing researches on game area have rarely dealt with game users but mainly focused on the studies and utilization of game production technologies; and, in cases of studies on games users, their subjects have been hardly more than observations of users' behaviors in relation to the performance to achieve certain goals or themes of a game; for example, upgrading a character's level or obtaining rewards through "defeat". Therefore, it is necessary to analyze the actions of SNS game users from the perspective of behavioral selections caused by various motivations of human beings rather than approaching from the perspective of problem solving methods. In order to accomplish this goal, fist of all, Lazzaro's People Fun model and motivation theory of SNS users will be analyzed. Secondly, relevant materials from 13 SNG cases will be collected. Games' events and the functional actions of users will be classified. Lastly, the primary actions of SNG users will be classified into 8 different types and motivations - action patterns will be analyzed based on the classified materials.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.137-144
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• 2013

The use of fiber-reinforced polymer (FRP) reinforcing bars in concrete structures has been increased as an alternative of steel reinforcement which has shown greater vulnerability to corrosion problem. However, the long-term performance of concrete members with FRP reinforcement is still questioned in comparison to the used of steel reinforcement. This study presents the results of an experimental study on the long-term behaviors of GFRP (glass fiber reinforced polymer) bar reinforced concrete beams after exposed to accelerated aging in an environmental chamber with temperature of $46^{\circ}C$ ($115^{\circ}F$) and 80% of relative humidity up to 300 days. The objectives of this research was to compare strength degradation and change of ductility between GFRP reinforced concrete beams and steel reinforcement beams after accelerated aging. Two types (wrapped and sand-coated surface) of GFRP bars and steel were reinforced. in concrete beams. Test results show that the failure modes of GFRP bar reinforced concrete beams are very similar with traditional RC beams, and the change of load-carrying capacity of steel reinforcing concrete beam is greater than that of GFRP bar reinforcing concrete beam under the accelerated aging. Test result also shows that the use of GFRP reinforcing in concrete could be introduced more brittle failure than that of steel reinforcing for practical application. The deformability factor up to compression failures indicates no significant variation before and after exposure of accelerated aging.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.799-813
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• 2011

Increasing mountain biking (MTB) in forest recreation areas is changing the behavioral patterns in the areas where hiking has been a dominant activity, and it may cause ecological and social impacts to the areas. This study examined hikers' perceived conflicts by MTB including the relationship between socio-demographic and visiting characteristics and perceived conflict. On-site survey was conducted in Mudeungsan Provincial Park (MPP), Korea, during September, 2010. Out of 388 hikers participated in the survey, 374 responses were used for data analysis. 30.2% of the respondents encountered or saw MTB (avg.: 1.7 times) in MPP. Overall, 77.1% of respondents thought MTB in MPP was a problem. 73.5%~83.2% of respondents perceived conflict by four major MTB behaviors (e.g., too fast running MTB in trails; MTB bikes occupying trails; MTB bikes passing by hikers too closely; MTB bikers doing unpleasant behaviors to hikers). Based on the type of conflict, 48.5~62.4% of respondents fell in the type of "social values conflict (SVC)", 11.1~32.4%, "interpersonal conflict (IC)", and 16.8~26.6%, "no conflict (NC)", respectively. Types of conflicts were related with sociodemographic (e.g., gender, age, education) and visiting characteristics (e.g., number of visits, experience of encountering MTB). Such relationships were nonexistent in most cases when the "experience of encountering MTB" was controlled.

• Journal of Korean Academy of Nursing
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• v.26 no.4
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• pp.768-781
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• 1996

The problem of care of patients and families with Alzheimer's disease has become a conscious raising social policy issue in Korea. The government of the Republic of Korea has become cognizant of the situation and has begun searching for ways to remedy it. Thus, there is a need for a comprehensive under-standing of the situation in which patients and their families are struggling and the enormous problems of care. With a realization of the urgent need, this study was done to investigate the situation and the care needs of families with patients with Alzheimer's Disease, and to compare the effectiveness of services utilized by the families in terms of cost and effects on patient's conditions and on family live. The Subjects for the study were 29 families with hospitalized patients, 25 families utilizing hospital outpatient clinics, 14 families utilizing day care facilities, and 16 families with homebound patients. A total of 84 families were interviewed by four trained interviewers using structured and semistructured questionnaires. The data produced from these interviews included : the patient's stage of Alzheimer's disease, patient's bizarre behavior, hours spent on patient care per day, family burden and quality of life, direct and indirect costs encountered in the care of patients, and the families' evaluation of the effectiveness of the services received. The data were analyzed to determine the relationships between family charactersistics, patient's conditions and services utilization. The effectiveness of each of the service entities was assessed through families evaluation and hoped for service and comparisons were made between services in terms of the cost-effectiveness ratios. After initial comparison of cost-effectiveness ratios, further analysis was done to compare between groups for incremental effectiveness for each incremental unit of cost to determine the most cost-effective service entities. The findings of the study are as fellows : 1. The choice of living arrangement and the types of services are a function of the stage of Alzheimer's condition and the economic status of the family. 2. Comparision of the cost of care showed that most expenses were encountered in by families with hospitalization, families using outpatient services, and families using day care services in that order. The least expense was involved in the care of homebound patients. The economic burden felt by families was in the same order as expenses. 3. The average number of hours spent on daily patient care was 9.9 hours for the outpatient clinic users, 9.7 hours for homebound patients, and 5.4 hours for day care users. 4. There were significant differences in the patient's conditions (CDRL), bizarre behaviors and the families's burden by living arrangement and /or types of service. However, no significant difference was found between groups in the family's quality of life. 5. The families rated the services of day care center as most effective for the care of the patients and families, except for a few families who had experienced some improvement in the patient's conditions. The outpatient clinic users expressed psychological comforts mainly in that the patient was being taken care of. For those hospitalized patients, families expressed the comfort of being relieved of the burden of care and that the patient is being professionally cared for. Form the analysis of the costs, hours of patient care, patient's bizarre behaviors, family's quality of life and burdens, and family's evaluation of services, it is concluded that up to the mid stage of Alzheimer's condition, the utilization of day care center services is found to be the most cost-effective, and toward the end stage of the Alzheimer's disease, it is hoped that there will be a establishment of long term or short term in-patient facilities for the protection of patients and preservation of the integrity of families for less cost. Thus. it was concluded that the family centered system of care is the most effective for Korea with systematic support systems developed for the care of patients and their families according to the needs of families as the patient's condition deteriorates.

• Korean Journal of Social Welfare
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• v.60 no.2
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• pp.131-153
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• 2008

Based upon the first national sample of adult men and women, the study aims to examine the prevalence of chid sexual abuse in Korea and factors related to the incidence of child sexual abuse. The results of the study show that 20.8% of the sample experienced one or more types of sexual abuse in their childhood, which indicates that Korean society is not any longer immune to child sexual abuse. With regard to how to cope with sexual abuse, "not informed to anyone and did not get any help at all" is the most major one for all types of sexual abuse. Even those who got help were reported to depend heavily upon private routes such as parents, relatives, or friends, indicating the urgency of establishing systematic intervention schemes for the problem. The results of a logistic regression analysis show that gender of the child, involvement in delinquent behaviors, economic status of the family, number of siblings, and residence in high-crime region are significantly related to the incidence of child sexual abuse. These results of the study would be expected to provide a useful guideline for developing policies or intervention programs aimed to prevent or address child sexual abuse.