• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.551-556
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• 2012

Fatigue is known to detrimentally affect a person's performance. Also, fatigue may reduce effectiveness and efficiency of marine officers and crew members. The purpose of this research is to understand on the status of the marine officers' fatigue. In this study, we carried out the questionnaire survey which is related to the marine officers' fatigue factors such as work, sleep and rest hour or period, sleepiness, casual factor, fatigue symptom, etc. The questionnaire contained 25 questions and it was distributed among 1,033 marine officers(deck officers 607 and engineers 426). The results of this survey show that marine officers' fatigue is a casual factor in marine accidents such as collisions, groundings and there was a fatigue difference between deck officers and engineers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.132-137
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• 2005

This paper addresses what amount of whole-body vibration is exposed to pilots of UH60 helicopters during flight. To measure the whole-body exposed from the feet and seat, the 12-axis vibration measurement system was used. It enables simultaneous measurement of vibration exposure from the body contact area of the feet, hip and back. The measured 12-axis vibration signals are exploited to the comfort level of UH60 helicopters during flight. It is shown that the evaluated ride value is close to $0.74{\sim}0.79m/s^2$ and that it is equivalent to the semantic scale of 'fairly uncomfortable'. To assess the health effects of whole-body vibration exposed to pilots of UH60 helicopters during their flight, the rms-based and VDV(vibration dose value)-based evaluation results of measured four-axis vibration signals are shown in this work. The fatigue-decreased proficiency limit, whose level is half of the exposure limit, is expected to come after the two-hour flight. The exposure limit is shown to reach after the 10-hour flight.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.411-414
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• 2009

Photo-capacitor electrodes are attracting great attention because of their high capacitance and potential applications in electronic devices. Carbon capacitor, active carbon capacitor and its combination will be fabricated using simple sandwich capacitor electrode method as carbonaceous material on each type of capacitor electrodes with 20 ${\times}$ 15 mm cell size. Carbon/active carbon cell was fabricated using sol-gel process with 120oC dry temperature in l hour and using sintering process with 500oC in 2 hour. The effect of sintering temperature on carbon properties was also investigated with X-ray diffraction technique to get the best sintering temperature. The detail of fabrication process will be explained. Elemental composition in electrode material can be measured using quantitative spectroscopic as and a cyclic voltammetric technique was used to study the combined effects of electrode material and effect of annealing temperature and also time on the capacitance of thermally treated in capacitor electrode. In this work, characterization impedance technique is used to measurement of capacitance and giving complementary results. Active carbon as carbonaceous material has a better capacitance in charge/discharge process with mean thickness $32{\mu}m$ and with particle size $1{\mu}m$ to $4.5{\mu}m$ in 20 ${\times}$ 15 mm sample size of capacitor electrode.

• Journal of Computing Science and Engineering
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• v.6 no.1
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• pp.67-78
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• 2012

People are willing to spend more for their health. Traditional medical services are hospital-centric and patients obtain their treatments mainly at the clinics or hospitals. As people age, more medical services are needed to exceed the potentials of this hospital-centric service model. In this paper, we present the design and implementation of CardioSentinal, a 24-hour heart care and monitoring system. CardioSentinal is designed for in-home and daily medical services. It mainly focuses on the outpatients and elderly. CardioSentinal is an interdisciplinary system that integrates recent advances in many fields such as bio-sensors, small-range wireless communications, pervasive computing, cellular networks and modern data centers. We conducted numerous clinic trials for CardioSentinal. Experimental results show that the sensitivity and accuracy are quite high. It is not as good as the professional measurements in hospital due to harsh environments but the system provides valuable information for heart diseases with low-cost and extreme convenience. Some early experiences and lessons in the work will also be reported.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.188-188
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• 2011

Recently, scaling down of ULSI (Ultra Large Scale Integration) circuit of CMOS (Complementary Meta Oxide Semiconductor) based electronic devices, the electronic devices, become much faster and smaller size that are promising property of semiconductor market. However, very narrow interconnect line width has some disadvantages. Deposition of conformal and thin barrier is not easy. And metallization process needs deposition of diffusion barrier and glue layer for EP/ELP deposition. Thus, there is not enough space for copper filling process. In order to get over these negative effects, simple process of copper metallization is important. In this study, Cu-V alloy layer was deposited using of DC/RF magnetron sputter deposition system. Cu-V alloy film was deposited on the plane SiO2/Si bi-layer substrate with smooth surface. Cu-V film's thickness was about 50 nm. Cu-V alloy film deposited at $150^{\circ}C$. XRD, AFM, Hall measurement system, and AES were used to analyze this work. For the barrier formation, annealing temperature was 300, 400, $500^{\circ}C$ (1 hour). Barrier thermal stability was tested by I-V(leakage current) and XRD analysis after 300, 500, $700^{\circ}C$ (12 hour) annealing. With this research, over $500^{\circ}C$ annealed barrier has large leakage current. However vanadium-based diffusion barrier annealed at $400^{\circ}C$ has good thermal stability. Therefore thermal stability of vanadium-based diffusion barrier is desirable for copper interconnection.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.12
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• pp.1046-1052
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• 2016

For the safe driving of autonomous vehicles, accurate position estimation is required. Generally, position error must be less than 1m because of lane keeping. However, GPS positioning error is more than 1m. Therefore, we must correct this error and a map matching algorithm is generally used. Especially, road marking intensity map have been used in many studies. In previous work, 3D LIDAR with many vertical layers was used to generate a local intensity map. Because it can be obtained sufficient longitudinal information for map matching. However, it is expensive and sufficient road marking information cannot be obtained in rush hour situations. In this paper, we propose a localization algorithm using an accumulated intensity local map. An accumulated intensity local map can be generated with sufficient longitudinal information using 3D LIDAR with a few vertical layers. Using this algorithm, we can also obtain sufficient intensity information in rush hour situations. Thus, it is possible to increase the reliability of the map matching and get accurate position estimation result. In the experimental result, the lateral RMS position error is about 0.12m and the longitudinal RMS error is about 0.19m.

• Hwankyungkyoyuk
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• v.24 no.1
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• pp.26-39
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• 2011

The purpose of this study is to review the current state of energy education in Korea and identifies barriers faced by teachers in doing energy education. For this purpose, this study carried out a questionnaire survey targeting energy saving policy research-schools. The results of this research are as follows. First, teachers facing barriers in energy education pointed out the lack of teaching text and students' interest in energy, and work stress as main barriers. Second, teachers facing barriers in energy education rather than teachers not facing barriers are inclined to do more education at Ordinance hour and Jongrye hours. It implies that more energy education textbooks for Ordinance hour and Jongrye hours need to be developed. Third, teachers facing barriers in energy education desire more chances for training program, compared with teachers who do not feel barriers. It implies that opportunities for teacher training program need to be expanded.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1259-1268
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• 2017

The alpha eigenvalue problem in multigroup neutron diffusion is studied with particular attention to the theoretical analysis of the model. Contrary to previous literature results, the existence of eigenvalue and eigenflux clustering is investigated here without the simplification of a unique fissile isotope or a single emission spectrum. A discussion about the negative decay constants of the neutron precursors concentrations as potential eigenvalues is provided. An in-hour equation is derived by a perturbation approach recurring to the steady state adjoint and direct eigenvalue problems of the effective multiplication factor and is used to suggest proper detection criteria of flux clustering. In spite of the prior work, the in-hour equation results give a necessary and sufficient condition for the existence of the eigenvalue-eigenvector pair. A simplified asymptotic analysis is used to predict bands of accumulation of eigenvalues close to the negative decay constants of the precursors concentrations. The resolution of the problem in one-dimensional heterogeneous problems shows numerical evidence of the predicted clustering occurrences and also confirms previous theoretical analysis and numerical results.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.386-393
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• 2018

Purpose: Chicken cutting is done manually, which is inefficient, unhygienic, and carries a high accident risk during processing. This study develops and evaluates an automatic chicken cutting machine that suits small-scale workplaces. Methods: This study developed an automatic chicken cutting machine equipped with four traverse blades and two longitudinal blades. An experiment was conducted with various blade rotating speeds and tray feed rates to evaluate the machine's performance. The chicken loss rate and chicken piece weights were measured to calculate the coefficient of variation (CV), thereby determining processing uniformity. Results: The optimal cutting conditions with the smallest chicken loss rate were 0.05 m/s tray feed speed and 18.8 m/s and 16.4 m/s for the traverse and longitudinal blades, respectively. The processing ran at 55.3 chickens per hour and the chicken pieces were more uniform when using the device than for hand-work processed pieces. Conclusions: The loss rate increased in proportion to the cutting-blade rotation speed due to the high cutting rate in meat. The loss rate also increased as the tray feed speed slowed because the cutting blade pushed the chicken meat. The tray feed speed should be increased to improve the amount processed per hour.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.79-88
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• 2019

Purpose: This study was conducted to understand the client relationship experience of the physical therapists working at elderly care facilities and to lay the foundation for finding the identity of physical therapists. Methods: In-depth interviews were conducted on eight incumbent physical therapists who had experienced working in elderly care facilities for at least one year. Data collection was conducted between June and September 2017, and the interview took an hour to an hour and a half to complete. After an in-depth interview, it was arranged as a file and analyzed according to the four steps of the phenomenological research method of the Giorgi. Results: Data were collected and analyzed; 19 categories, 6 themes and 5 domains were derived. Six themes were presented according to the 5 domains; the subject of relationships included 'diversity elderly'; context of relationships included 'the world of elderly nursing homes I did not know'; influence of relationships included 'the physical therapist is heartbroken because of the tormenting elderly'; condition of relationships included 'a reality that is tied to work'; aspects of relationships included 'how to reestablishing relationships with the elderly' and 'recognized and identified as a physical therapist'. Conclusion: This study shows that physical therapists working in elderly care facilities generally tend to fulfill their responsibilities and interact with clients; we found that identity of physical therapists was primarily defined by relationship experiences with patients.