• Journal of Korea Multimedia Society
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• v.22 no.3
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• pp.366-373
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• 2019

The development of monitoring and analysis systems to increase productivity while saving energy is needed as a method to reduce huge amount of energy consumed in the process of producing large forged products. In this paper, we propose a system to monitor and analyze energy usage in real-time collected from gas-meter, wattmeter, and thermometer based on IoT installed in forging factories. The system consists of a data collection server for collecting and processing data from IoT- based platform and existing SCADA equipment and ERP/MES system in forging factories, and an application server for providing services to users. To develop the system, the overall system structure is logically diagrammed, and the databases configuration and implementation modules to efficiently store and manage data are presented. In the future, the system will be utilized to reduce energy consumption by analyzing energy usage pattern and optimizing process works with real-time energy usage and production process data for each facility.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.147-158
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• 2017

The purpose of this study is to investigate the determinants of the SNS usage time depending on SNS motive of the youth workers. Although previous studies revealed that there are many motivations for SNS usage, it is not known which factors determine usage time of each SNS motive. In this study, we constructed the unbalanced panel data of the Korean Education & Employment Panel data. Among three different SNS motives such as information exchange, social networking, and fun pursuit, gender, physical health, extraversion, and conscientiousness affected the usage of SNS when the motivation was information exchange. When it was personal connection, the size of organization, education, physical health, subjective happiness, job satisfaction, neuroticism, and agreeableness did. When it was fun & interest, foreign company, status of children, subjective happiness, and job satisfaction did. Based on the findings, we discussed theoretical and practical implications.

• Journal of Korean Biological Nursing Science
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• v.16 no.2
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• pp.80-89
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• 2014

Purpose: The purpose of this study was to investigate relationships between short sleep, obesity, and screen time. Methods: Data were obtained from a survey using a sample of 1,166 academic, and 597 vocational high school students. A structured questionnaire was used to assess demographics, hours spent in sleep, TV viewing, internet usage, and game playing. Obesity was determined using the body mass index. Descriptive statistics, Cochran Mantel Haenszel Chi-square test, and multiple logistic regression with dummy variables were performed. Results: Short sleep (<8 hours/day) was significantly related to obesity, not in academic school students, but in vocational school students. Academic high school students who had enough sleep (${\geq}8$ hours/day), had more time spent on TV viewing, internet usage, and game playing. Similar results were found in vocational high school students except for internet use. Interestingly, students with better school performance spent significantly less time in TV viewing, internet usage, and game playing, and therefore had a lower risk of obesity in academic school students. Conclusion: There is a significant relationship between short sleep and obesity that was found only in vocational high school students. The relationship between short sleep and screen time was not significant in Korean high school students.

• The Journal of Korean Physical Therapy
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• v.30 no.2
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• pp.54-57
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• 2018

Purpose: Most studies have reported pain in the head-neck and upper-limbs according to smartphone usage, which is related to the proprioception sense in the head and neck, but there have been few studies. Therefore, the aim of this study was identify the adverse effects of the proprioceptive sense in the head-neck according to smartphone usage. Methods: Twenty-seven young adults (male: 9, female: 18) were enrolled in this study. The proprioceptive sense was measured through the joint reposition sense error and neural positon error in the head-neck during smartphone usage for 0, 5, and 20 minutes. The Noraxon MyoMotion system was used to record the joint position angle and neutral positon in the head-neck. One-way repeated ANOVA was used to identify the differences between the three smartphone use durations and the least-squares difference was used as a post hoc test. The data were analyzed using SPSS 18.0 software. Results: The joint reposition sense error and neural positon error in the head-neck were significantly different among the 0, 5, and 20 minutes of smartphone usage (p<0.05). In the post hoc test, the joint reposition sense error and neural positon error showed a significant difference between smartphone use for 0 minute and 5 minute, and between smartphone use for 0 minute and 20 minutes. Conclusion: This study suggests that smartphone use within 5 minutes can have adverse effects on the proprioceptive sense. Therefore, it is necessary to consider the appropriate use time and break time when using smart phones.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.127-141
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• 2009

While the ever-increasing complexity of automotive software systems can be effectively managed through the adoption of a reliable real-time operating system (RTOS), it may incur additional resource usage to a resultant system. Due to the mass production nature of the automotive industry, reducing physical resources used by automotive software is of the utmost importance for cost reduction. OSEK OS is an automotive real-time kernel standard specifically defined to address this issue. Thus, it is very important to develop and exploit kernel mechanisms such that they can achieve minimal resource usage in the OSEK OS implementation. In this paper, we analyze the task subsystem, resource subsystem, application mode and conformance classes of OSEK OS as well as the OSEK Implementation Language (OIL). Based on our analysis, we in turn devise and implement kernel mechanisms to minimize the dynamic memory usage of the OSEK OS implementation. Finally, we show that our mechanisms effectively reduce the memory usage of OSEK OS and applications.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.13-22
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• 2017

Accurate assessment of agricultural groundwater usage is an essential task to cope with drought that occurs irregularly in time and location. In this study, the agricultural groundwater usage was calculated in nationwide public wells (1,386 bedrock wells) during 5-year period (2010-2014) by using electric power consumption and well specification data. National average of agricultural groundwater usage per each well was estimated as $66.2m^3/day$, corresponding to 21.6% of total permitted volume of groundwater in each well. Chungcheong Nam-do had the highest usage with 38-55.6%. The value increased to 58.1% when the total permitted volume was based upon the supply standard against drought, and the value reached 100% in Chungcheong Nam-do. In Ganghwa distirct that suffered from severe drought in recent years, the average groundwater usage was 61.4%. In 2014, when the drought was the most severe with 45% precipitation of the average annual rainfall, the nationwide usage was turned out to be 25.6%, indicating about 4% higher than average agricultural groundwater usage 21.6%. Therefore, the quantitative assessment of groundwater usage in this study signifies that adequate use of groundwater is crucial to cope with agricultural drought.

• Journal of the Korean Society of School Health
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• v.26 no.1
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• pp.45-53
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• 2013

Purpose: The purpose of this study is to identify the relationship between smartphone usage time and university students' physical and mental health. Methods: A survey of 320 university students in Ulsan was conducted from Nov. 26 to 28, 2012, using a self-report questionnaire. The structured questionnaire consisted of questions regarding socio-demographic characteristics, the amount of time spent using smartphones, physical health, and mental health. The collected data were analyzed by the t-test, ANOVA, and the pearson correlation coefficient, using the SPSS 18.0 Program. Results: The mean of the time spent using smartphones was $154.94{\pm}93.97$ minutes. Female university students tend to spend significantly longer time using smartphones than male university students (p<.01). Smartphone usage time had a significant positive correlation with the students' score of smartphone addiction (r=.26, p<.001). Conclusion: The findings of this study can be utilized as a basic material to prevent physical and mental health problems caused by smartphone usage.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.3
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• pp.237-262
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• 2020

Part-time instructors are contributing to the production of excellent human resources through education and research, strengthening research competitiveness, and national and social knowledge and academic development. Therefore, academic and research information services for part-time instructors are essential for their educational and research activities. In this study, researcher suggested various methods for providing efficient educational and academic information services by surveying and analyzing their information environment, information needs, and educational and academic information recognition and usage behavior by applying the survey method to part-time instructors.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.1
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• pp.1-6
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• 2021

In this paper, to expand the use of standalone street lights, an algorithm for controlling LED energy consumption was proposed. The proposed method uses an LED module of a standalone street light divided into n zones. This is a method of reducing total power consumption by preventing the increase in power consumption due to high heat generation by weakly operating the entire LED according to the illuminance. When the amount of sunlight decreases, the whole LED operates weakly and then brightens, and unlike streetlight that act as streetlight, a method of dividing LEDs by area and limiting the number of LEDs operating according to illumination intensity was proposed. This is a way to use a lot of time with limited battery capacity by reducing the generation of heat that consumes the most power in streetlight. It is also a method of continuously changing the initial usage area to improve the total usage time of the LED substrate. As a result of the experiment, it was found that the proposed method extends the service time because it generates less heat than the conventional stand-alone streetlight.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1346-1352
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• 2009

Warranty cost of automobile parts varies depending on the parts failure rate in a warranty region of individual markets. Parts failure rate is significantly affected by usage-rate given that other stressors of individual markets are similar. Accordingly, warranty cost can be predicted by failure modeling which reflects usage-rate and using a stochastic process. In this paper, one-dimensional approach is used by applying accelerated failure time model on the assumption that the usage-rate is linear. Such model can explain changes in parts failure rate depending on the changes in usage-rate since it can be expressed as a function of usage-rate. Therefore, acquisition of usage-rate in a new market will automatically lead to estimate of failure rate even without warranty data and warranty cost of parts can be predicted through a renewal process in replacement cases. A case study using warranty data of two real markets is presented in the application part of this paper.