• Communications of the Korean Mathematical Society
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• v.35 no.1
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• pp.43-61
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• 2020

We extend the work of A. Beauville on rank 2 vector bundles on a smooth curve in several directions. We give families of examples with large dimension, add new existence and non-existence results and prove the existence of indecomposable limits with arbitrary rank. To construct the large dimensional families we use the examples of limits of rank 2 trivial bundles on ℙ² and ℙ³ due to C. Banica. We also consider a more flexible notion: limits of trivial bundles on nearby curves.

• Korean Journal of Social Welfare
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• v.59 no.4
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• pp.111-136
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• 2007

The National Basic Livelihood Security(NBLS) System implemented from October 2000 has expanded cash assistance to cover the poor who are able to work in our country. Although the cash assistance for them has positive aspects of providing basic livelihood security for all people, but many scholars have also pointed out its negative aspects such as a decrease in labor supply among the poor. In order to provide policy implications for the cash assistance program of our country as well as the US, this paper examines the impact of Temporary Assistance for Needy Families(TANF) on poverty among single mothers and their families using data from March Current Population Survey of $1991{\sim}2002$. TANF imposes strong work requirements and time limits to recipients as conditions for cash assistance, which are major sub-components of TANF. Therefore, this paper analyzes TANF by looking at work requirements and time limits separately, not by looking at TANF as a single policy. The research findings show that work requirements significantly decreased income and increased poverty among single mothers. Although time limits show income increasing effects and poverty decreasing effects, it seems further studies on time limits are needed at this point. The research findings of this paper provide important lessons for welfare to work cash assistance of our country as well as the US.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.3
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• pp.733-742
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• 2013

The Korea has significant tidal current energy resources, but it is so hard to work underwater for tidal turbine installation. Therefore commercial diving work is very important for tidal current generator. Also, Jangjuk channel is vary famous as proper area to generate tidal current energy. Nevertheless, no one is studied about characteristics of commercial diving works with installation of tidal current generator. The purpose of this study is to introduce commercial diving with work types and investigate critical limits of diving working under the conditions, which are working only to minutes at slack tide during the neap tide. As the results, work types are five as like mooring installation, OMAS(Offshore Maintenance Access System), support structure installation, cable and turbine installation. Here, the original construction period is expected about 4 months, but the construction take 18 months to complete. The cause of extends construction period is insufficiency of researching tidal current conditions at the site and ignorance of slack tide which need to secure diving working time. Total diving working times are 110th during 18 months, the highest percentage of diving times is turbine installation about 43.6 %, and cable, mooring installation and support structure construction are 27.3 %, 15.5 %, 13.6 %, respectively. On the basis of this study, estimation of times of commercial diving is possible with work types of tidal current power, and has a significance as basic data to determining construction period.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.375-383
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• 2023

Objectives: Coal-fired power plants feature diverse working conditions, including multi-layered employment structures and irregular work cycles due to outsourcing and non-standardized tasks. The current uniform occupational environment measurement systems have limitations in accurately assessing and evaluating these varied conditions. This study aims to propose alternative measurement and assessment strategies to supplement existing methods. Methods: Major domestic coal-fired power plants were selected as the study targets. To prepare for the study and establish strategies, work processes were identified and existing occupational environment measurement results were compared and analyzed. The study proceeded by employing three strategies: specific exposure groups (SEGs) measurement, continuous monitoring, and supplementary measurements, which were then compared and discussed. Results: Previous exposure index evaluations (5,268 cases) indicated that crystalline silica, a type of respirable particulate matter, had detection limits below the threshold (non-detectable) in 82.6% (4,349 cases) of instances. Exposures below 10% of the exposure limit were observed at a very low concentration of 96.1%. Similar exposure group measurements yielded results where detection limits were below the threshold in 38.2% of cases, and exposures below 10% of the limit were observed in 70.6%. Continuous monitoring indicated detection limits below the threshold in 12.6% of cases, and exposures below 10% of the limit were observed in 75.6%. Instances requiring active workplace management accounted for more than 30% of cases, with SEGs at 11.8% (four cases), showing a higher proportion compared to 3.0% (four cases) in continuous monitoring. For coal dust, exposures below 10% of the limit were highest in legal measurements at 90.2% (113 cases), followed by 74.0% (91 cases) in continuous monitoring, and 47.0% (16 cases) in SEGs. Instances exceeding 30% were most prevalent in SEGs at 14.7% (five cases), followed by legal measurements at 5.0% (eight cases), and continuous monitoring at 2.4% (three cases). When examining exposure levels through arithmetic means, crystalline silica was found to be 104.7% higher in SEGs at 0.0088 mg/m³ compared to 0.0043 mg/m³ in continuous monitoring. Coal dust measurements were highest in SEGs at 0.1247 mg/m³, followed by 0.1224 mg/m³ in legal measurements, and 0.0935 mg/m³ in continuous monitoring. Conclusions: Strategies involving SEGs measurement and continuous monitoring can enhance measurement reliability in environments with irregular work processes and frequent fluctuations in working conditions, as observed in coal-fired power plants. These strategies reduce the likelihood of omitting or underestimating processes and enhance measurement accuracy. In particular, a significant reduction in detection limits below the threshold for crystalline silica was observed. Supplementary measurements can identify worker exposure characteristics, uncover potential risks in blind spots of management, and provide a complementary method for legal measurements.

• Journal for History of Mathematics
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• v.25 no.3
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• pp.15-27
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• 2012

This paper aims to examine Alan Turing's life at the centenary of his birth and to discuss a philosophical implication of his work by concentrating on halting theorem particularly. Turing negatively solved Hilbert's decision problem by proving impossibility of solving halting problem. In this paper I claim that the impossibility implies limits of reason, and accordingly that the marginality in cognition and/or in action should be recognized.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.30
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• pp.43-50
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• 1994

Work environment has been changed as the development of new techknowledge such as computer industry. The more new techknowledges, the more changes in our work conditions. But our cognitive limits can't pace up to the change of work environment. As a result, rapid work transfer occurs frequently, which increase work stress, work error and deleterous work performance. For many changes, this paper analyse the effect of work performance when the information used in mental work is changed as a sudden impact during dexterous work conditions. When the information impact is intruded in works, performances are reduced, but the react time does not respond sensitively then cognitive process time. So it is recommended to refer the cognitive time as a index of performance when mental work is included.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.2
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• pp.87-96
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• 2017

Objectives: Improvement of the reliability of work environment measurement results is one of the principal subjects to be resolved in the field of industrial hygiene. Thus, this study was conducted in order to review domestic programs for enhancing the reliability of work environment measurement results and propose a more efficient management plan for workplace monitoring. Materials and Methods: The current domestic programs reviewed in this study are the quality control system and evaluation system for industrial hygiene laboratories, the reliability system accompanied by KOSHA (the Korea Occupational Safety and Health Agency), the system of permissible exposure limits and observed inspection system for permissible exposure limits. Their contents and data were analyzed by reviewing articles, reports, and guidelines related to reliability improvement for work environment measurement results. Results: As a result of the literature review, all the domestic programs investigated in this study had both merits and demerits in terms of considering the reliability of work environment measurement results. In particular, the fact that preliminary notification is provided to the head of a workplace before implementation would be an obstacle for elevating the reliability of work environment measurement results. Conclusions: Based on the review results obtained from this study, it is proposed that on-site measurement without preliminary notification should be considered for a more efficient inspection system that would enhance the reliability of workplace monitoring.

• Journal of the Korean Society of Safety
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• v.26 no.3
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• pp.47-51
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• 2011

Work platform is temporary material that many workers use in construction field, but many workers construct and use the work platform without considering safety standards, workers who have not the knowledge of safety standards construct the work platform in weakness and use the work platform in unstable, According to the statistics in 2009, 1230 people were injured at the work platform. Among them, victims by falling account for about 77% and mostly lead to fatal injuries. we have studied and survey about the safety or danger of the work platform(set limits to duble scaffold) in construction field and about how many workers observe safety standards of the work platform. According to the result of this survey, 24%~100%(average : 68%) of the work platform in survey is not observe the safety standards.

• Management & Information Systems Review
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• v.13
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• pp.141-162
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• 2003

This article discusses the issues of the estimated size and characteristics of irregular employment work force in Korea after IMF economic crisis in 1997. The issues of the estimated size of irregular employment work force originated from different concepts and its operationalizations among the labor economists, despite their utilization of the same labor force data, 'Economically Active Population Survey(EAPA)' collected from Korea National Statistical Office(KNSO). And the issues contribute toward the understandings of the irregular employment and the limits of the EAPA, despite its various usefulness. This article also describes the summary characteristics of irregular employment work force from both sides of labor supply and its demand. The major characteristics of irregular employment work force on the labor supply side appears in the concentration of social minorities, i.e. woman, the aged, lower educated and skilled populations. On the labor demand of irregular employment work force, the majority of it concentrated on the establishments under 10 employees, and probably the important incentives for irregular employment work force of the firms is labor cost efficiency. Finally, this article propose an alternative against the discrimination between the regular and irregular work force.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.237-242
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• 2004

In design stage of high precision manufacture/inspection FAB building, it is necessary to investigate the vibration allowable limits of high precision equipment and to study a structure dynamic characteristics of C/R and Sub-structure in order to provide a structure vibration environment to satisfy thess allowable limits. The aim of this study is to investigate the dynamic characteristics of PC-Type mock-up structures designed for next TFT LCD FAB through vibration measurement and analysis procedure, therefore, to provide a proper dynamic structure design for high precision manufacture/inspection work process, which satisfy thess allowable limits.