• The Mathematical Education
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• v.37 no.1
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• pp.115-138
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• 1998

We seek the possibility of introduction of Fractals to the high school math. curriculum through identifying Fractals teaching programs appropriate for the scopes and sequences in math. education for the high school students. We presented the contents of Fractal theory suitable for the high school students. The following subjects were chosen to be introduced; self-similarity, Fractal dimension, Cantor set, Sierpinsky triangle, Sierpinsky carpel Koch curve, Koch island, perimeter estimate of rugged profiles drawn on paper, and chaos game. We developed the working papers and the criteria for appraisal. Each working paper focuses on the activities in which students can solve the given problems, understanding the characteristics and ideas of Fractals. The working papers were given to the second year students who take science course, and the degree of achievements were analyzed based on the appraisal criteria. The results show that it is possible to introduce Fractals to the high school students.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.124-127
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• 2001

We consider the routing and wavelength assignment problem in survivable WDM transport network without wavelength conversion. We assume the single-link failure and a path protection scheme in optical layer. When a physical network and a set of working paths are given, the problem is to select a link-disjoint protection path for each working path and assign a wavelength for each working and protection path. We give an integer programming formulation of the problem and propose an algorithm to solve it based on column generation technique and variable fixing. We devise a branch-and-price algorithm to solve the column generation problem. We test the proposed algorithm on some randomly generated data and test results show that the algorithm gives very good solutions.

• Management Science and Financial Engineering
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• v.11 no.2
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• pp.85-103
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• 2005

In this paper, we consider the routing and wavelength assignment problem in survivable WDM transport network without wavelength conversion. We assume the single-link failure and a path protection scheme in optical layer. When a physical network and a set of working paths are given, the problem is to select a link-disjoint protection path for each working path and assign a wavelength for each working and protection path. We give an integer programming formulation of the problem and propose an algorithm to solve it. Though the formulation has exponentially many variables, we solve the linear programming relaxation of it by using column generation technique. We devise a branch-and price algorithm to solve the column generation problem. After solving the linear programming relaxation, we apply a variable fixing procedure combined with the column generation to get an integral solution. We test the proposed algorithm on some randomly generated data and test results show that the algorithm gives very good solutions.

• Journal of the Ergonomics Society of Korea
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• v.33 no.2
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• pp.167-174
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• 2014

Objective: This research focuses on the working environment of office workers and aims to propose an ideal seating posture and chair design. Background: Generally, office workers having to seat in a fixed posture for long periods of time tend to suffer from an increased rate of musculoskeletal disorders. Method: The measurement and survey of 123 office workers on their working conditions and literature survey will lead to a suggestion of an ideal seating posture and workstation design theory. Results: Work environment satisfaction appeared low for chair and desks. Work-related pain over the last year was experienced among 47.2% of the respondents in shoulder (34.2%), neck (30.9%). Observation of working posture revealed that only 27.6% of workers utilize backrest during work. Conclusion: Office work embodies many situations where risks of musculoskeletal disorders may be high. Thus, the seated workplace must be set up to allow proper seating posture for workers. Application: The results of this study can be applied as baseline data for preventing musculoskeletal disorders of office workers.

• Wind and Structures
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• v.8 no.4
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• pp.295-307
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• 2005

The paper describes the work of the IAWE Working Group WBG - Reliability and Code Level, one of the International Codification Working Groups set up at ICWE10 in Copenhagen. The following topics are covered: sources of uncertainties in the design wind load, appropriate design target values for the exceedance probability of the design wind load for different structural classes with different consequences of a failure, yearly exceedance probability of the design wind speed and specification of the design aerodynamic coefficient for different design purposes. The recommendations from the working group are summarized at the end of the paper.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.159-165
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• 2009

Through the understanding of the change of productivity and the ability of error recovery according to aging and the assessment and analysis of them, we may take this research to contribute to make a design for the road-map to help set up the policy of employment for old generation. For this we have taken an experiment of the coordination tester for 100 person who are chosen randomly and analysed the collected data using SAS, which is one of widely used statistical analysis packages. The main results are as follow: $\circledcirc$ The result of regression between the working speed and the length of the correction of error shows independence. (pr>0.2029). $\circledcirc$ The regression between age and working speed is statistically significant. (pr<0.0001) $\circledcirc$ The relation between age and the length of the correction of error is not significant. (pr>0.9123).

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.53.1-53.1
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• 2021

Dwarf galaxies are the most abundant objects in the universe. Hence, understanding the dwarfs is important but relatively little is known due to the lack of computing power and limitations in the telescope resolution. We thus use the state-of-the-art NewHorizon simulation, which is a set of cosmological hydrodynamical simulations, to dissect the quenching mechanism working on dwarf galaxies by inspecting the star formation and mass history of individual galaxies. It is known that internal (AGN, SN, stellar feedback) and external (major and minor mergers, ram pressure stripping, strangulation) mechanisms affect the quenching of dwarfs. Because of the combination of these mechanisms, periodicity in the star formation history of the dwarf galaxies is expected. To check for their periodicity, Fourier transform was performed on the star formation history. By comparing the physical timescales and the periodicity, we determine the dominant effect working on the dwarfs. Then, we compare the dominant effects working on the galaxies according to their varying properties.

• Safety and Health at Work
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• v.12 no.3
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• pp.370-376
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• 2021

Backround: Working condition surveys are widely recognized as useful tools for monitoring the quality of working life and the improvements introduced by health and safety policy frameworks at the European and national level. The Italian Workers' Compensation Authority carried out a national survey (Insula) to investigate the employer's perceptions related to working conditions and their impact on health. Methods: The present study is based on the data collected from the Italian survey on health and safety at work (INSULA) conducted on a representative sample of the Italian workforce (n = 8,000). This focuses on the relationship between psychosocial risk factors and self-reported health using a set of logistic and linear regression models. Results: Working conditions such as managerial support, job satisfaction, and role act as protective factors on mental and physical health. On the contrary, workers' risk perceptions related to personal exposure to occupational safety and health risks, concern about health conditions, and work-related stress risk exposure determine a poorer state of health. Conclusions: This study highlights the link between working conditions and self-report health, and this aims to provide a contribution in the field of health at work. Findings show that working conditions must be object of specific preventive measures to improve the workers' health and well-being.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.48-53
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• 2001

In Korea, the modification of working conditions of the train crews, with the launch of the KTX, demands a new set of regulations. The analysis on the french case will be a first step, in spite of socio-economical differences between Korea and France, in making new rules for the train crews of the KTX.

• Journal of International Academy of Physical Therapy Research
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• v.3 no.2
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• pp.469-474
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• 2012

The purpose of this study is to analyze the correlation between the stature and the muscle performance ratings and the subjective discomfort rations at performing lower arm's pronation and supination according to change sin the height of working table for more efficient performance at designing a working table and performing a work. For the purpose, this study conducted an experiment targeting 40 people in their 20s, who were classified into 4 groups each group composing 10 people at intervals of 5cm from the standard stature of 166.5cm. The experiment measured the maximum isometric pronation and the supination muscular power, and at measuring the factors, the heights of working tables were set as 800mm, 850mm, and 900mm. From the measurement results, it was found that the stature and the maximum muscular power was correlated. That is, as the experiment groups's average stature is higher, the maximum muscular power was higher. For the correlation between the motion patterns(pronation and supination) and the maximum muscular power, it was seen that the maximum muscular power was higher at performing the pronation than the supination. In the correlation between motion patterns and the subjective discomfort ratings, it was seen that the subjective discomfort rating was higher at performing the supination than the pronation. For the correlation between height adjustment and the subjective discomfort ratings, as the height of working table was lower, the subject discomfort rating was lower. Therefore there was no difference in the maximum muscular power according to the height changes of working table, but it was found that as the working table was higher, the user felt more comfortable.