• Transactions of the Korean Society of Machine Tool Engineers
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• 제16권6호
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• pp.15-20
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• 2007

Recently the machine industry is rapidly advanced for improving productivity. Especially an effort decreased error factors of machine tool continuously is being studied. In this paper, we propose a method that decreased vibration in the high speed spindle. By appling 6-sigma technique(DMADOV), we can grasp the influence between the housing design and a rotation accuracy. For a correct conclusion, we measure an actual spindle and analysis by $ARMD^{(R)}$(rotation analysis program). inally we find out influenceable design factors and the improvement condition about 20.7%.

• Journal of the Korea Safety Management & Science
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• 제9권2호
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• pp.19-31
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• 2007

If you examine the Industrial Disaster Analysis Content that occurs every year in the small and medium enterprise, industrial disaster occurs because of manager's lack of safety and worker's unprepared safety education. Therefore effective safety education systems are needed to offer adequate knowledge and technology to the workers. On this research, to give an effective education way to decrease industrial disaster we administered to the workers who are in charge of 300 workplace in Incheon area to search actual condition of industrial disaster and to disclose a link between industrial disaster and industrial safety education. We put in effect on frequency study and examined x2 using SPSSWIN 10.0. On the research, the results shows that the industrial safety education and training are in effect regularly and the satisfaction are low. But the manager's satisfactions are high through safety education. So it shows that we need to find a way to put in effect safety education to satisfy the workers.

• ETRI Journal
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• 제32권4호
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• pp.503-511
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• 2010

WiBro radio frequency (RF) repeater is used for solving the problem of partial shadow areas in the wireless communication field that uses time-division duplexing (TDD) mode. In this paper, a method to efficiently generate TDD signals for WiBro RF repeater is proposed and its digital circuit is implemented. A TDD signal is detected from RF signals transmitted/received to/from RF repeater and then inputted again into the RF repeater, so that it can operate normally. First, the envelope of downlink signals is detected and then clamped to extract the basic form of a TDD signal using an operational amplifier circuit. Next, the TDD signal is generated by restoring and filtering the shape which has been distorted by the wireless channel. The algorithm and system to acquire TDD signal are developed with a goal to have simple but powerful functions with as little cost as possible. The proposed method is implemented as an RF-digital integrated system and verified through the experiments under the same condition as actual WiBro service environment.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2652-2660
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• 2021

The gamma-ray exposure doses in decontamination operation after a nuclear accident were evaluated with a consideration of various geometrical conditions and specific gamma-ray energies. The calculation domain is organized with three residence types and each form is divided into two kinds of geometrical arrangements. The position-wise air KERMA values were calculated with an assumption of evenly distributed gamma-ray source based on Monte Carlo radiation transport analysis using the MCNP code. The radioactivity is initially set to be unity to be multiplied by the deposition value measured in the actual accident condition. The workforce data set depending on the target object was determined by modifying the Fukushima report. The external exposure doses for decontamination workers were derived from the calculated KERMA values and the workforce analysis. These results can be used to efficiently determine the workforce required by the characteristics of the area and the structure to be decontaminated within the dose limits.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제19권1호
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• pp.58-70
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• 2020

Detour behavior on the expressway means that the driver uses the local road by passing the part of the expressway which is stagnant at the time of the traffic demand such as holidays. Since the detour rate was estimated through the survey at toll gate in the past, there was a difficulty in estimating the actual detour rate due to the small sample of the survey. In this study, we use DSRC-based route travel data to conduct empirical studies on detour patterns such as the estimation of actual detour rate, the improvement of travel time using detour road, and the correlation between traffic conditions on the expressway and detour rate. On the day of Chuseok and the day before Chuseok, the analysis of Giheung-DongtanIC→OsanIC and Seopyeongtaek IC→Walgott JC showed that the use of detour roads increased gradually during the congestion of the main line and travel time reduced when using detour roads, However, when the traffic congestion of the main line is not severe, the travel time increases when using the detour roads. The correlation between the traffic condition of the expressway and the actual detour rate has a negative correlation, which is consistent with the congestion pattern of the main line. The results of this study can be used to overcome limitations of detour pattern research based on surveys in the past and to establish a detour strategy for expressway sections where traffic demand is concentrated.

• Journal of Korean Society for Geospatial Information Science
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• 제22권1호
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• pp.13-22
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• 2014

Recently, many civil appeals have been occurred in land management work because of discord between cadastral records and actual land use pattern. it is important to select parcels for land alternation exactly using land information and to evaluate compensation cost according to scenarios for advancing this problem. This study operated GIS spatial overlay based on serial cadastral maps and actual-width of the road and analyzed the number and area of the parcels for land alternation by the land classification and ownership applying fuzzy membership function according to occupation ratio to road. Also compensation cost was calculated according to scenarios using individual public land price information of the parcels for land alternation and was arranged by district as Eup and Myeon according to land classification and ownership. This study can efficiently support the work of the parcels for land alternation complying with the financial condition of local government, by supplying compensation cost according to scenarios to the parcels of land alternation by district as Eup and Myeon.

• Korean Journal of Optics and Photonics
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• 제28권6호
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• pp.304-313
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• 2017

The finite element analysis for optimizing a mirror system consisting of a large-diameter mirror and flexures requires numerous, repetitive calculations and corrections of the actual model to satisfy the given design conditions. In general, modification of this real model is conducted by reconfiguring nodes of the elements. The reconfiguration is very time-consuming work, to fix the continuity of each of the newly formed component nodes at the interfaces. But the process is a very important factor in determining the analysis time. To save time in modeling and actual computation, and to attain faster convergence, we present a new opto-mechanical analysis using non-shared node connections at each of the interfaces of the optical components. By comparing the results between the new element model and a conventional element model with shared node connections, we found that the opto-mechanical performance was almost the same, but the time to reach the given condition was drastically reduced.

• Korean Journal of Rural Living Science
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• 제8권2호
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• pp.119-124
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• 1997

In this study we tried to give a decision on propriety of working conditions, to present ideas on reducing work loads, and to grope for efficiency of agricultural works. For this we examined the actual working conditions of cultivating welsh onion in the summer ground. And we improved harmful factors that affect farmer's health by considering results of previous study and farmer's subjective sensation. And we measured. compared, and analyzed the farmer's work loads before and after improvement. The results of this study are as follows ; 1. According to examine the actual working conditions of cultivating welsh onion in the summer ground, farmers have experienced physical and mental chronic fatigue on the basis of farmer's appel to eye - fatigue and sun - burned skin on hot working environment including excessive ultraviolet rays, the rough ground condition, inconsistent arrangement of working stand and sorter, heavy - weared habits, and unsuitable working posture. 2. When we improved harmful factors that affect farmer's health, conformed the effects on important work efficiency index such as heart rate, electromyovolume, body temperature, and microclimate inside clothing and work loads were decreased by eliminating the hillock and obstacles of ground, decreasing the clothing weight, using proper clothing appliances such as hat and sunglasses, controlling height of working stand and sorter suitably, improving the working postures and methods as using assistant appliances, alloting the working time and sequence effectively and presenting the light gymnastic exercises and rest for fatigue restoration.

• Journal of Information Technology Services
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• 제20권5호
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• pp.11-28
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• 2021

As untact travel has become a new trend in leisure culture due to the spread of COVID-19, car camping market is rapidly increasing. The sales of car camping-related goods increased by up to 600 percent, and the sales of SUV in Korea also increased by about four times. Despite the growth of the car camping market, there is a lack of research on the actual condition of the car camping market or research on the user's perspective. Therefore, in this study, a survey of actual camping users was conducted to derive factors that they consider important in camping, and through this, a car camping map was produced. As a result, two types of maps were produced: a map about the car camping site and convenience facilities closest to the car camping site in Gangwon-do, and a hash tag themed map based on keywords for each car camping site. We gathered data on portal sites and social media to obtain information related to camping sites and proceeded with analysis using text mining. In addition, we extracted keywords using network analysis techniques and selected key themes that represent them. This allows the user to choose a car camping site by selecting keywords that suit their taste. We hope that this research will help car camping researchers as a prior study and provide a foundation for leading a clean camping culture through clean camping campaign. Also, we hope that car camping users will be able to do quality trip.

• Journal of Korean Public Health Nursing
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• 제27권3호
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• pp.450-465
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• 2013

Purpose: The purpose of this study was to identify cognitive impairment and risk factors among elderly persons aged 60 or more in Korea using raw data from the 2008 Elderly Survey: Basic Analysis Report of Actual Living Condition of the Elderly and Welfare Need Survey in Korea. Methods: This study was conducted using raw data obtained from 13,335 subjects representing elderly persons aged 60 or more in Korea. Data were analyzed using SPSS 19.0 software. Results: The rate of cognitive impairment was found to be 22.0%. Logistic regression analysis became more prevalent with increased aged. In addition elderly subjects with the following factors showed increased cognitive impairment: mails; underweight; slept well for 3 to 4 days per week at most; lack of high intensity physical activity; Eub/Myoun area; did not live alone; did not graduate from high school; un-employed; lack of active social participation, and not computer/Internet savvy. Conclusion: This study identified cognitive impairment and risk factors among elderly persons aged 60 or more in Korea using samples representing elderly persons aged 60 or more throughout the country.