• Journal of The Korean Association For Science Education
• /
• v.12 no.3
• /
• pp.49-59
• /
• 1992

New-Piagetian theory has proposed that mental capacity and mental demand do a critical role in human cognitive processes. In this study, the students' mental capacity and the mental demand of the given problems were examined. The principal findings of the study are as follows; (1) There was no significant difference among achievement scores of subjects (3rd grade students of middle school, 2nd grade students of high school, 3rd grade students of high school) in the items of balance that needed specific content knowledge. But, in the Newton's 2nd law items that needed specific content knowledge, there was significant difference be ween3rd grade students of middle school and high school students(2nd, 3rd). According to increase of mental demand, middle school students' achievement score appeared to decrease linearly. However high school students' achievement score didn't change untill they faced the items of critical mental demand. When mental demand was beyond critical mental demand,their score was decreased rapidly. (2) According to hierchical analysis of items, the more mental demand an item needed, the higher or at least the same hierachical item was. These results showed that mental demand was the main factor which decided diffculties of problem solving (3) It was possible for students to solve the newton's 2nd law item that had one or two more mental demand relative to balance beam item. Although the item needed the same mental demand.students recognized that the Newton's 2nd law items were easier than the balance beam items.

• Child Health Nursing Research
• /
• v.4 no.1
• /
• pp.105-115
• /
• 1998

The purpose of the study was to test the reliability and validity of the Korean version of Children's Health Locus of Control Scale (CHLC), an instrument designed to measure health locus of control in children aged 7 to 12. The scale was administered to 467 children in grades 4 to 6, enrolled in 2 elementary schools located in city. The mean age of the subject was 10.03 (SD=1.33). The findings were as follows: 1. Cronbach alpha coefficient for internal consistency was .69 for the total, and .67, .65, and .56 on the respective subscales. 2. Construct validity was supported through factorial isolation of three theory consistent subscales : internal, chance, and powerful others. Two items did not fit well with the originally developed subscale. The total percent of varience explained by 3 factors was 34.5%. The result of the factor analysis according to Kaiser's criterion revealed that the scale was consisted of 5 factors. But, The items of the subscales were rather inconsistent with the dimensions of the locus of control concept. 3. There were significant differences according to parent's educational level and occupation, and birth order on the scores of the CHLC. There were no significant differences according to grade level and sex. 4. The score of the CHLC was significantly correlated with the self concept of the children(r=.14, p<.001). The result indicated that the Korean version of Children's Health Locus of Control Scale was valid and reliable in measuring health locus of control concept in children, even though luther research is required to reconfirm and increase the reliability of the instrument. CHLC could be used for study explaining the health related behavior of the children and research project related to health education program.

• Proceedings of the Korean System Dynamics Society
• /
• 2002.02a
• /
• pp.19-40
• /
• 2002

The intent of this study is to develop system dynamics model for assessment of organizational and human factors in nuclear power plant which can contribute to secure the nuclear safety. Previous studies are classified into two major approaches. One is engineering approach such as ergonomics and probability safety assessment(PSA). The other is social science approach such like sociology, organization theory and psychology. Both have contributed to find organization and human factors and to present guideline to lessen human error in NPP. But, since these methodologies assume that relationship among factors is independent they don't explain the interactions among factors or variables in NPP. To overcome these limits, we have developed system dynamics model which can show cause and effect among factors and quantify organizational and human factors. The model we developed is composed of 16 functions of job process in nuclear power, and shows interactions among various factors which affects employees' productivity and job quality. Handling variables such like degree of leadership, adjustment of number of employee, and workload in each department, users can simulate various situations in nuclear power plant in the organization side. Through simulation, user can get insight to improve safety in plants and to find managerial tools in the organization and human side. Analyzing pattern of variables, users can get knowledge of their organization structure, and understand stands of other departments or employees. Ultimately they can build learning organization to secure optimal safety in nuclear power plant.

• Survey Research
• /
• v.10 no.2
• /
• pp.1-21
• /
• 2009

The purpose of this study is to compare the estimates of housework time by gender using two representative methods of time use study: Time Diary and Stylized Survey Questionnaire. Our analysis is based on the data from the Lifetime Use Survey(2004), which used time-diary questions, and the Korean Labor & Income Panel Study(KLIPS 2004), which used stylized questions on housework hours. The results show that men over-report their housework time in the stylized time use questions. In contrast, women under-report their housework time, which is unusual in the previous studies on response errors and reporting gap. Subgroup analysis shows that widowed/divorced men tend to over-report their contribution to housework more than other groups whereas among women, groups burdened with employed work, caring and housework underestimate their housework time. This reporting gap is explained by gendered norm and perception of time pressure. The theory to explain under-reporting of the housework time has been undeveloped in the previous studies. Our study suggests that perceptions of time pressure be an important factor to explain women's reporting gap of housework estimates.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.10
• /
• pp.722-733
• /
• 2006

In scalable streaming application, there are two important knobs to tune to effectively exploit the underlying network resource and to maximize the user perceivable quality of service(QoS): layer selection and packet scheduling. In this work, we propose Semantics Aware Packet Scheduling (SAPS) algorithm to address these issues. Using packet dependency graph, SAPS algorithm selects a layer to maximize QoS. We aim at minimizing distortion in selecting layers. In inter-frame coded video streaming, minimizing packet loss does not imply maximizing QoS. In determining the packet transmission schedule, we exploit the fact that significance of each packet loss is different dependent upon its frame type and the position within group of picture(GOP). In SAPS algorithm, each packet is assigned a weight called QoS Impact Factor Transmission schedule is derived based upon weighted smoothing. In simulation experiment, we observed that QOS actually improves when packet loss becomes worse. The simulation results show that the SAPS not only maximizes user perceivable QoS but also minimizes resource requirements.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.77-81
• /
• 2004

In this paper a novel line interactive UPS (Uninterruptible Power Supply) using the two 4-leg VSCs and AC line reactor is proposed. The 4-leg Voltage Source Converter(VSC) can use the DC link voltage effectively by the 3-D SVPWM method. Hence the DC battery voltage can be reduced by $15\%$ in comparison to that of the conventional line-interactive UPS system. One VSC is in parallel with the AC line reactor of the power source side, and the other is in series with the load. The parallel 4-leg voltage source inverter controls three-phase line voltage independently in order to control the line reactor current indirectly. It eliminates the neutral line current and the active ripple power of the source side using the pqr theory so that unity power factor and the sinusoidal source current can be achieved even though both the source and the load voltages have zero sequence components. The series 4-leg voltage source inverter compensates the line voltage and allows the load voltage to be balanced and harmonic-free. Both of parallel and series 4-leg voltage source inverters always act as independently controllable voltage sources, so that three-phase output voltage shows a seamless transition to the backup mode. The feasibility of the proposed UPS system has been investigated and verified through computer simulation results.

• The Journal of Information Systems
• /
• v.20 no.3
• /
• pp.257-277
• /
• 2011

The current study categorizes factors of smartphone into three, using KANO model: attractive factors which cause only product satisfaction, must-be factors for dissatisfaction, and one-dimensional factors for both. Based on it, it presents a new model for the effects that smartphone factors have on satisfaction or dissatisfaction. The purpose is to theoretically explain that smartphone factors on which companies and users place a high value can actually affect satisfaction or dissatisfaction. After choosing 15 factors out of 25 which had been selected through literature study, these were divided into attractive, must-be, and one-dimensional ones. 93 out of 109 questionnaires returned were used for analysis. After frequency analysis using SPSS were conducted on the surveys, the factors were grouped, based on KANO table. The grouping results are as follows. Attractive factors include 'expansion slots for external memory, battery desorption, brand awareness, mobile banking and internet telephony'. Must-be ones include 'multi-touch, information security, entertainment, information retrieval, location based service and SNS. Finally, 'screen visibility, size of internal memory, the amount of internal memory, battery life, and response to after-sales service' are classified as one-dimensional factors. A critical finding of this paper is that since the results are different depending on the operating system of smartphones, it must be taken into consideration in studies on smartphones. The wide and rapid spread of smartphones has changed people's lifestyle as well as business environment, which forces companies to compete with each other to adapt to the changed circumstances. In this competitive system, studies on smartphone factors of satisfaction and dissatisfaction are essential for firms to establish a new strategy. From this point of view, the present paper is expected to be a basic material for enterprises not only to develop goods and services that maximize customer satisfaction and minimize dissatisfaction, but also to establish the future business strategy.

• The Journal of Information Systems
• /
• v.29 no.3
• /
• pp.53-75
• /
• 2020

Purpose Despite the continued rise in the popularity of mobile MMORPGs, the previous studies mainly focused on negative results of playing MMORPG such as violence and game addiction. In addition, previous studies that verified game play motives were not enough to explain user's fundamental motives for MMORPG play. To verify the positive role of playing MMORPG, this study focused on stress coping strategies on continued play MMORPG, and divided factors into two dimensions: escapism and coping with system. The purpose of this study is to comprehensively identify the discriminatory effects of each factor on users' self-control, and the effect of self-constrol and behavioral adapatation on continued use intention for MMORPG. Design/methodology/approach This study was designed to examine the structural relationships among MMORPG users' escapism, system coping, self-control, behavioral adaptation and continued use intention for MMORPG. Findings The results from this study are as follow. First, the participants' effect-based escapism had a positive impact on self-control, whereas cause-based escapism had a negative impact on self-control. Next, proactive coping and reactive coping for system problem had a positive impact on self-control. In addition, Self-control had a positive impact on behavioral adaptation and continued use intention for MMORPG. Lastly, the behavioral adaptation to MMORPG had a positive impact continued use intention. The results of our study can suggest the positive effects of coping strategy on users' self-control and behavioral adaptation by applying the theory of both escapism and coping with system. Based on our results, game companies should develop contents that can gratify users' coping motives and enhance self-control and behavioral adaptation.

• Journal of The Korean Association For Science Education
• /
• v.24 no.3
• /
• pp.596-611
• /
• 2004

Based on conceptual change theory, cognitive conflict is known as an important factor for conceptual change even though there are still questions about its positive and negative effects on science learning. However there are little research which propose types of meaningful(constructive) cognitive conflict in learning science. The purpose of this study is to find out how are the anxiety types of cognitive conflict to which high school students respond in the action-reaction task, and to reveal what's the characteristic of the explanatory hypothesis according to the anxiety types. The result of this study indicated that first, the characteristics of the anxiety types of the cognitive conflict were classified as eight types. Especially the students who belong to the types of conviction of logical misconception and reasonable modification suggested explanatory hypothesis close to physical nature. On the other hand, the students who showed other types of anxiety except the two types of anxiety suggested temporary supported hypothesis or simple explanatory hypothesis based on students' observation and intuition. Finally we discussed the importance and the implication of the types of anxiety in applying the cognitive conflict strategy to science instruction.

• Child Health Nursing Research
• /
• v.10 no.1
• /
• pp.89-97
• /
• 2004

Purpose: Adolescence is viewed as a critical period in the formation of health behavior and many health behaviors developed during this era persist into adulthood. Social-cognitive theory, self-efficacy as a central construct, has been used to predict and intervene the health behavioral patterns in adolescent. Previous research demonstrated that the attachment in childhood and self-esteem as psychosocial factors are predictors of the health efficacy in adolescent and it is viewed as solely an antecedent for the lifelong health behavior. Method: To investigate the path pattern of attachment in childhood, self-esteem and health efficacy in adolescents, 381 adolescents in high school from two urban cities in Korea were recruited for cross-sectional sample. Attachment in childhood was measured using Mother-Father-Peer Scale. Self esteem was measured with Hare self esteem. Perceived self efficacy in Health was measured by the School Health Efficacy Questionnaire. The path analysis revealed a significant relationship between attachment in childhood and self-esteem, self-esteem and health efficacy in adolescents. Self esteem was the strongest contributing factor for health efficacy in adolescent. The results suggest that attachment in childhood may aid in formulating positive self -esteem in adolescents and self-esteem played a major role in predicting health efficacy in adolescents. Conclusion: Therefore, self-esteem enrichment should be incorporated with adolescent health promotion and certainly should be a component in any health education program in school health program and interventions. These results have implications of psychosocial and family related factors on health promotion and health education for the health care provider with regard to primary and secondary prevention in adolescent population.