• Steel and Composite Structures
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• 제19권3호
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• pp.697-711
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• 2015

It is well known the importance of considering hysteretic energy demands for the seismic assessment and design of structures. In such a way that it is necessary to establish new parameters of the earthquake ground motion potential able to predict energy demands in structures. In this paper, several alternative vector-valued ground motion intensity measures (IMs) are used to estimate hysteretic energy demands in steel framed buildings under long duration narrow-band ground motions. The vectors are based on the spectral acceleration at first mode of the structure Sa($T_1$) as first component. As the second component, IMs related to peak, integral and spectral shape parameters are selected. The aim of the study is to provide new parameters or vector-valued ground motion intensities with the capacity of predicting energy demands in structures. It is concluded that spectral-shape-based vector-valued IMs have the best relation with hysteretic energy demands in steel frames subjected to narrow-band earthquake ground motions.

• 한국농공학회지
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• 제35권2호
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• pp.23-32
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• 1993

This paper describes the background and the development of a hydrologic network flow model. The model was development to simulate daily water demand and supply for selected stream reaches within a watershed, and used as a tool for evaluating, simulating, and planning a water resources system. The proposed network flow model considers daily runoff from subareas, various water demands, and diversion structures within each subarea. Daily streamflow at a reach is simulated after balancing the water demands from subareas. The lateral inflow from subareas is simulated using a modified tank model. Total water demands consist of the daily demands for agricultural, domestic, industrial, livestock, fishery, and environmental uses within a rural district. The return flow, diversions from sources and storage components such as reservoirs were also incorporated into the mode l . The developed model is a generalized version that may be applied to different combinations of river reaches for a given system. This may help potential users identify areas where water supply does not suffice the demands for different time horizons.

• Journal of Korean Biological Nursing Science
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• 제12권2호
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• pp.114-126
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• 2010

Purpose: To examine the levels of the disease-related knowledge and educational demands of pre-dialysis, chronic renal failure patients at different GFRs and stages. Methods: This study used a cross-sectional survey and aimed at 116 pre-dialysis, chronic renal failure patients, who were registered and received regular treatment from December 1 to December 31, 2009 at the nephrology departments of tertiary medical centers in Seoul. Stages were classified into Stage 3, 4 and 5 depending on GFR ranges. To measure the levels of knowledge and educational demands, the tool, which were first invented by Young Ae Lim (1996) and then modified by Hyo Sun Lim (2005) to adjust the knowledge and educational demands measuring tool for hemodialysis patients to pre-dialysis patients with chronic renal failure, was used. Collected data was analyzed with the SPSS WIN 12.0 program (average, standard deviation, Pearson's correlation coefficient, t-test and ANOVA). Results: There was a significant difference in the disease-related knowledge levels of the subjects at each stage (F=24.41, p=.000). The Scheffe post hoc test confirmed that patients at higher stages had higher levels of knowledge of their disease. Also, although the results showed that patients at higher stages had higher educational demands, there was no significant difference among the groups (F=1.259, p=.288). Conclusion: As patients have different levels of knowledge of the disease and educational demands depending on their stages, it is important to develop and use a systematic education program that reflects the demands and levels of patients at each stage in order to help pre-dialysis patients with chronic renal failure with self-management and improve their quality of life.

• Earthquakes and Structures
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• 제1권4호
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• pp.327-344
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• 2010

This paper summarizes results of a comprehensive analytical study aimed at evaluating the influence of strong ground motion duration on residual displacement demands of single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems. For that purpose, two sets of 20 earthquake ground motions representative of short-duration and long-duration records were considered in this investigation. While the influence of strong ground motion duration was evaluated through constant-strength residual displacement ratios, $C_r$, computed from the nonlinear response of elastoplastic SDOF systems, its effect on the amplitude and height-wise distribution of residual drift demands in MDOF systems was studied from the response of three one-bay two-dimensional generic frame models. In this investigation, an inelastic ground motion intensity measure was employed to scale each record, which allowed reducing the record-to-record variability in the estimation of residual drift demands. From the results obtained in this study, it was found that long strong-motion duration records might trigger larger median $C_r$ ratios for SDOF systems having short-to-medium period of vibration than short strong-motion duration records. However, taking into account the large record-to-record variability of $C_r$, it was found that strong motion duration might not be statistically significant for most of the combinations of period of vibration and levels of lateral strength considered in this study. In addition, strong motion duration does not have a significant influence on the amplitude of peak residual drift demands in MDOF systems, but records having long strong-motion duration tend to increase residual drift demands in the upper stories of long-period generic frames.

• Journal of Preventive Medicine and Public Health
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• 제52권5호
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• pp.299-307
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• 2019

Objectives: While occupational stress has long been a central focus of psychological research, few studies have investigated how immigrant microbusiness owners (MBOs) respond to their unusually demanding occupation, or how their unresolved occupational stress manifests in psychological distress. Based on the job demands-resources model, this study compared MBOs to employees with regard to the relationships among emotional demands, job resources, and depressive symptoms. Methods: Data were derived from a cross-sectional survey of 1288 Korean immigrant workers (MBOs, professionals, office workers, and manual workers) aged 30 to 70, living in Toronto and surrounding areas. Face-to-face interviews were conducted between March 2013 and November 2013. Results: Among the four occupational groups, MBOs appeared to endure the greatest level of emotional demands, while reporting relatively lower levels of job satisfaction and job security; but MBOs reported the greatest job autonomy. The effect of emotional demands on depressive symptoms was greater for MBOs than for professionals. However, an inspection of stress-resource interactions indicated that though MBOs enjoyed the greatest autonomy, the protective effects of job satisfaction and security on the psychological risk of emotional demands appeared to be more pronounced for MBOs than for any of the employee groups. Conclusions: One in two Korean immigrants choose self-employment, most typically in family-owned microbusinesses that involve emotionally taxing dealings with clients and suppliers. However, the benefits of job satisfaction and security may protect MBOs from the adverse mental health effects of job stress.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제33권3호
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• pp.395-423
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• 2019

본 연구의 목적은 향후 수학교과서의 추론 과제 개발에 대한 시사점을 제공하기 위하여, 고등학교 수준 수학교과서 3종을 연구 대상으로 수열 단원에 제시된 추론 과제의 인지적 난이도 수준과 추론 과정 구성요소를 분석하는 것이다. 연구 결과, 3종의 수학교과서의 수열 단원에 제시된 추론 과제의 대부분이 인지적 난이도 수준이 낮은 것으로 나타났으며, 인지적 난이도 수준이 낮은 추론 과제는 하나의 추론 과정 구성요소만을 요구하는 것으로 나타났다. 반면에 추론 과제의 일부만이 인지적 난이도 수준이 높은 것으로 나타났으며, 인지적 난이도 수준이 높은 추론 과제는 다양한 추론 과정 구성요소를 요구하는 것으로 나타났다. 이러한 연구 결과를 바탕으로 인지적 난이도 수준이 낮은 추론 과제보다는 학생들에게 다양한 추론 과정의 학습기회를 제공하고 추론의 본질을 심도있게 이해시킬 수 있는 인지적 난이도 수준이 높은 추론 과제 개발에 대한 필요성을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권4호
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• pp.1101-1121
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• 2024

Thorough understanding of user demands and formulation of product development strategies are crucial in product design, and can effectively stimulate consumer behavior. Scientific categorization and classification of demands contribute to accurate design development, design efficiency, and success rates. In recent years, e-commerce has become important consumption platforms for smart wearable products. However, there are few studies on product design and development among those related to promoting platform product services and sales. Meanwhile, design strategies focusing on real consumer needs are scarce among smart wearable product design studies. Therefore, an empirical consumer demand analysis method is proposed and design development strategies are formulated based on a categorized interpretation of demands. Using representative smart bracelets from wearable smart products as a case, this paper classifies consumer demands with three methods: big data semantic analysis, KANO model analysis, and satisfaction analysis. The results reveal that analysis methods proposed herein can effectively classify consumer demands and confirm that differences in consumer demand categories have varying impacts on consumer behavior. On this basis, corresponding design strategies are proposed based on four categories of consumer demands, aiming to make product design the leading factor and promote consumer behavior on e-commerce platforms. This research further enriches demand research on smart wearable products on e-commerce platforms, and optimizes products from a design perspective, thereby promoting consumption. In future research, different data analysis methods will be tried to compare and analyze changes in consumer demands and influencing factors, thus improving research on impact factors of product design in e-commerce.

• 대한화학회지
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• 제56권4호
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• pp.518-529
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• 2012

이 연구에서는 중학교 '과학2' 교과서에 서술되어 있는 '원소', '주기율표', '원자'에 대한 내용이 요구하는 인지 요구도를 분석하였다. 우리나라는 2007년 개정 교육과정에 의하여 처음으로 주기율표 및 그와 관련 내용들을 중학교에서 다루게 되어있다. 분석에 활용한 6종 과학 교과서에 서술된 내용이 어떠한 인지 수준을 요구하는 지를 알아내는 분석틀은 영국에서 개발된 CAT(Curriculum Analysis Taxonomy)의 3종류 분석틀을 사용하였다. 이 3종류 분석틀에 의하여 분석한 '과학2' 교과서에 서술된 내용이 요구하는 인지 수준들은 다음과 같았다. '원소'에 대한 교과서 서술이 더 이상 간단한 물질로 분리될 수 없는 순물질임을 이해하는 내용으로 후기 형식적 조작 수준이었다. 그러나 '원소'는 한 가지 종류의 원자만으로 이루어진 물질이라고 서술된 초기 형식적 조작 수준도 있었다. '주기율표'에 대한 교과서 서술이 다양한 종류의 원소들을 원소 기호를 이용하여 특정 기준에 따라 몇 가지 그룹으로 분류될 수 있음을 이해해야 하고, 실체를 범주화하는데 있어서 여러 기준으로 분류해야 하는 내용으로 후기 구체적 조작 수준이었다. '주기율표'를 여러 족들의 집함임을 알고 이원 분류표로 이해해야 하는 내용으로 초기 형식적 조작수준이었다. '원자' 구조와 연결 짓는 복합적 분류 체계로 주기율표를 표현하는 후기 형식적 수준도 있었다. '원자'에 대한 교과서 서술이 원자가 구조를 가진다는 것 그리고 원자가 같은 종류도 있고 다른 종류도 있다는 서술은 초기 형식적 수준이었다.

• 한국학교보건학회지
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• 제30권2호
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• pp.103-112
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• 2017

Purpose: The Purpose of this study was to examine school health teachers' burnout, engagement, job demands and job resources and to identify the factors that influence burnout and engagement. Methods: The participants were 222 school health teachers working in elementary, middle or high schools. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and hierarchical multiple regression. Results: The significant factors influencing burnout were rewards (${\beta}=-.51$), autonomy (${\beta}=-.15$), and job demands (${\beta}=.13$). These factors explained 42% of the variance in burnout. The significant factors influencing engagement were feedback (${\beta}=.49$), rewards (${\beta}=.21$), type of employment (${\beta}=.15$) and autonomy (${\beta}=.13$). These factors explained 49% of the variance in engagement. Conclusion: The study showed that job demands increase burnout, while job resources such as rewards and autonomy alleviate it. In addition, job resources, such as feedback, rewards and autonomy, increase engagement among school health teachers. Therefore, in order to reduce burnout and increase engagement among school health teachers, it is necessary to reduce the level of job demands and to provide enough job resources such as rewards, autonomy and feedback by improving the job environment.

• Computers and Concrete
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• 제19권6호
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• pp.689-699
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• 2017

An energy-based approach for determining earthquake safety of reinforced concrete frame structures is presented. The developed approach is based on comparison of plastic energy capacities of the structures with plastic energy demands obtained for selected earthquake records. Plastic energy capacities of the selected reinforced concrete frames are determined graphically by analyzing plastic hinge regions with the developed equations. Seven earthquake records are chosen to perform the nonlinear time history analyses. Earthquake plastic energy demands are determined from nonlinear time history analyses and hysteretic behavior of earthquakes is converted to monotonic behavior by using nonlinear moment-rotation relations of plastic hinges and plastic axial deformations in columns. Earthquake safety of selected reinforced concrete frames is assessed by using plastic energy capacity graphs and earthquake plastic energy demands. The plastic energy dissipation capacities of the frame structures are examined whether these capacities can withstand the plastic energy demands for selected earthquakes or not. The displacements correspond to the mean plastic energy demands are obtained quite close to the displacements determined by using the procedures given in different seismic design codes.