• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.765-773
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• 2009

The purpose of this study is to identify secondary chemistry teachers' abilities to carry-out experiment lesson successfully. As far as the research method is concerned, literature reviews, analyses of abilities to carry-out experimentation from science textbooks, and a survey of science teachers' perceptions of experimental ability were employed along with the progressive discussions among the authors. In order to identify secondary chemistry teachers' abilities to carry-out experimentation, we divided the experiment lesson into three stages of preparation, conduct and arrangement, and management of lab, and added the stage of safety. Each stage is classified into sub-areas, and the sub-area consists of subordinate elements. The safety stage was included separately to emphasize the importance of the safety issue in lab and experimental activities. The secondary chemistry teachers' abilities to carry-out experimentation are the abilities to perform experiments in person, presupposing the instruction of experiment, and can be featured with the use of reagent and measuring instruments, the preparation of sample, designing experiment, correct experimental habit and skillfulness, data processing, analysis and reasoning, and management of lab and safety.

• Journal of Korean Elementary Science Education
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• v.43 no.1
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• pp.18-34
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• 2024

This study aimed to examine the effects of a science-learning program based on data visualization on the science inquiry and creative problem-solving abilities of elementary school science-gifted students. Accordingly, this research developed a data visualization science-learning program using Tableau, which had twelve sessions. The subjects encompassed 61 students in three gifted classes taught by the researcher. The scientific inquiry ability test and creative problem-solving ability test modified to suit the environment and situation were given to the subjects before and after the treatment. The results confirmed that science learning based on data visualization had no significant impact on basic science inquiry skills. Among the subdomains, significant results were obtained only in the reasoning subdomain. Moreover, integrative inquiry ability was significantly affected, unlike basic inquiry abilities. Among the five subdomains, significant differences were observed in three subdomains (data conversion, data interpretation, and variable control). However, concerning the generation of hypotheses and the control of variables, students exhibited confusion regarding the process of variable control and the exact concept of hypothesis development. This study also evaluated the effects of the program's application on creative problem-solving abilities and found a significant impact. Additionally, it was significantly different in all four subdomains. The results were interpreted to be owing to the students' mastery of Tableau's features, collaborative learning through discussion and debate, and the thematic impact of the data visualization program emphasizing procedural thinking. Finally, this study presented implications for science learning based on data visualization and the future direction of education.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.5
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• pp.53-58
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• 2002

A recent development, a concrete-filled steel(CFS) pier is an alternative to a reinforced concrete bridge pier in an urban area, because of its fast construction and excellent ductility against earthquakes. The capacity of CFS piers has not been used to a practical design, because there is no guide of a seismic design for CFS piers. Therefore, the guide of a seismic design value is derived from tests of CFS piers in order to apply it to a practical seismic design. Steel piers and concrete-filled steel piers are tested with constant axial load using quasi-static cyclic lateral load to check ductile capacity and using the real Kobe ground motion of pseudo-dynamic test to verify seismic performance. The results prove that CFS piers have more satisfactory ductility and strength than steel piers and relatively large hysteretic damping in dynamic behaviors. The seismic performance of steel and CFS piers is quantified on the basis of the test results. These results are evaluated through comparison of both the response modification factor method by elastic response spectrum and the performance-based design method by capacity spectrum and demand spectrum using effective viscous damping. The response modification factor of CFS piers is presented to apply in seismic design on a basis of this evaluation for a seismic performance.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.39-50
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• 2007

This paper presents applications of the log-linear ROCOF(rate-of-occurrence-of-failure) and the Weibull ROCOF to model the failure rate of individual cast iron pipes in a water distribution system and provides a method of estimating the economically optimal replacement time of the pipes using the 'modified time-scale'. The performance of the two ROCOFs is examined using the maximized log-likelihood estimates of the ROCOFs for the two types of failure data: 'failure-time data' and 'failure-number data'. The optimal replacement time equations for the two models are developed by applying the 'modified time-scale' to ensure the numerical convergence of the estimated values of the model parameters. The methodology is applied to the case study water distribution cast iron pipes and it is found that the log-linear ROCOF has better modeling capability than the Weibull ROCOF when the 'failure-time data' is used. Furthermore, the 'failure-time data' is determined to be more appropriate for both ROCOFs compared to the 'failure-number data' in terms of the ROCOF modeling performances for the water mains under study, implying that recording each failure time results in better modeling of the failure rate than recording failure numbers in some time intervals.

• 한국노년학
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• v.28 no.4
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• pp.1265-1278
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• 2008

The purpose of this study was to study the Relationships between Sport for All Participation and Physical and Mental Function affecting the Elderly's Self-perceived Health. For accomplishing this purpose of this study, the 308 subjects were selected by the multi-stage stratified cluster sampling method from the Seoul, in the years of 2008. presently. Out of the 360 questionnaires responded to, only 308 were used for data analysis because 52 were responded to incompletely or incorrectly. The survey questionaries were used to collect data. The questionary for physical function state were developed and standardized by kung-hee chung(1993), yang-lae Kim(2005). And mental function state were divided two parts; self-perceived scale and depress scale. The questionary for self-perceived scale were based on MMSE-K(Mini Mental State Examination-Korea). The questionary for Depression were based on Depression Scale developed by Beck(1978), adapted in Korean and standardization by Lee Young-ho & Song Jong-yong(1991), regulated by Jo Gyu-whang(2004). From the analysis of this study, the following conclusions were obtained: First, according to the elderly people's participation in leisure sport activities, it partially affected physical and mental function state. Second, according to the degree of elderly people's participation in leisure sport activities, it partially affected physical and mental function state.

• Journal of Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.13-21
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• 2005

Advanced analysis and optimal design of steel arch bridges is presented. In the design method using an advanced analysis, separate member capacity checks after analysis are not required because the stability and strength of the structural system and its component members can be rigorously treated in the analysis. The geometric nonlinearity is considered by using the stability function. The Column Research Council tangent modulus is used to account for gradual yielding due to residual stresses. A parabolic function is used to represent the transition from elastic to zero stiffness associated with a developing hinge. An optimization technique used is a modified section increment method. The member with the largest unit value evaluated by AASHTO-LRFD interaction equation is replaced one by one with an adjacent larger member selected in the database. The objective function is taken as the weight of the steel arch bridge and the constraint functions account for load-carrying capacities and deflection requirements. Member sizes determined by the proposed method are compared with those given by other approaches.

• Journal of Korea Port Economic Association
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• v.23 no.4
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• pp.228-243
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• 2007

This study porvides an empirical overview of the import patterns of Incheon port using an Engle-Granger cointegration technique and Johansen's multivariate cointegraion methodology test to check the stationarity of the model. The empirical results show that the import in Incheon port related to the economic variables. This paper also applies rolling regression to our model, indicating that import are endogeneous to the economic variable.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.4
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• pp.267-291
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• 2010

Life can be kept in suspended animation either before fertilization at oocyte stage or after fertilization at different stages of embryonic development for a variety of reasons. It not only has potential applications in fertility preservation and management in human but also has important roles in the preservation and management of animal genetic resources, low-cost international movement of selected genetics, and rapid dissemination of germplasm through assisted reproductive technologies (ART) and genetic engineering. Currently, slow-freezing and vitrification are the two approaches by which oocytes and embryos can be cryopreserved for long-term storage. Both of these methods have their own advantages and disadvantages but allow the cryopreservation of oocytes and embryos with comparable efficiency. Vitrification of oocyte and embryos, although proven successful just 13 years after slow-freezing, is generally considered an emerging technology and appears to slow gain acceptance in both animal and human ART despite having controversial storage and contamination issues. In this manuscript, we discuss the basic techniques of oocyt/embryo cryopreservation and review the current status and recent developments in vitrification.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.301-307
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• 2021

In addition to the revival of the Internet of Things, embedded systems, which are at the core of the Internet of Things, require intelligent control as things change. Embedded systems, however, are heavily constrained by resources such as hardware, memory, time and power. When changes are needed to firmware in an embedded system, flash Memory must be initialized and the entire firmware must be uploaded again. Therefore, it is time- and energy-efficient in that areas that do not need to be modified must also be initialized and rewritten. In this paper, we propose how to upload firmware in installments to each sector of flash memory so that only firmware can be replace the firmware in the parts that need to be modified when the firmware needs to be modified. In this paper, the proposed method was evaluated using real target board, and as a result, the time was reduced by about half.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.459-466
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• 2016

This study examined the effects of robot-assisted therapy on the motor and functional recovery of the lower limbs in 53 subacute stroke patients. Robot-assisted therapy was performed using Lokomat? (Hocoma AG, Zurich, Switzerland) for thirty minutes per day, five times a week for four weeks. The outcome measures used were the Fugl-Meyer assessment, Motricity index(MI), Functional ambulation category(FAC), Berg balance scale(BBS) for gait function and balance ability, 10m walking test, K-Modified Barthel Index(K-MBI) for the activities of daily living and Mini mental state examination (MMSE), and Beck's depression inventory(BDI) for depression. All patients recruited underwent these evaluations before and after the four week robot-assisted therapy. For the evaluation, the somatosensory evoked potentials were used to assess the functional recovery. Robot-assisted therapy on the lower limb after subacute stroke showed improvement in motor strength, gait function, and the activities of daily living. All changes in terms of MI, FAC, BBS, and K-MBI exhibited a statistically significant difference after the four weeks robot-assisted therapy. The somatosensory evoked potential result showed a correlation with the MI and K-MBI. Robot-assisted therapy is believed to facilitate the motor and functional recovery of the lower limb in subacute stroke patients.