• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.773-781
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• 2013

Recently, an extended warranty of the system following the expiration of the basic warranty is becoming increasingly popular to the user. In this respect, we suggest a preventive maintenance model following the expiration of extended warranty with minimal repair warranty from the user's point of view in this paper. Under basic warranty and extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user. For the preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the numerical examples are presented to illustrate the purpose when the failure time of the system has a Weibull distribution.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.207-213
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• 2009

This research estimates the contribution to the Busan regional economy made by Busan Port's container cargo handling from the microscopic point of view. The cost is calculated and shown in the currency unit of Korea, won, per TEU. A questionnaire was conducted to 12 different types of maritime business to obtain total sales and performances of the companies. The total sales of maritime business related to container goods per the whole TEU was computed at 238,230won/TEU. This can be adopted as a new index to analyse the Busan regional economy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3182-3196
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• 2012

In this paper, we present a new LED (Light Emitting Diode) mood lighting system interacting with smartphones based on the generation of different light sequences. In the proposed system, one light sequence is considered to be one unit of the service contents, which is then transmitted through a network and played in an LED lighting system. To this end, we propose a novel generation scheme using a smartphone, and a decoding/playing mechanism in an LED lighting system. The lighting sequences have a fixed period divided into predefined time units. Two modes - basic and interpolation - are supported in each time unit when playing a color sequence. In the basic mode, the color is maintained for the entire time unit, whereas in the interpolation mode the color is interpolated. The sequence is decoded and played in the lighting circuit by changing the duty cycle of a PWM (Pulse Width Modulation) signal. A demonstration system of the overall proposed method was using smartphones, a server and an LED lighting system. The results from this experiment show the validity and applicability of the proposed scheme.

• Journal of Korea Planning Association
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• v.54 no.2
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• pp.5-16
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• 2019

The purpose of this study is to analyze the spatial characteristics of business-type-changed parcel in the Hongik-University commercial area, from the view point of commercial gentrification. A commercial gentrification occurs through a business-type-change in a spatial basic unit (microscopic spatial unit such as parcel) of an area which has not been considered in relavent policies and research. So, this study analyzed the spatial characteristics of business-type-changed parcels using the Cox's proportional hazard regression model. The main results of this study are as follows. First, as new developments in the adjacent area occur, the business-type-change probability increases. Second, by the commercial area division, the business-type-change probability is different. Finally, the accessibility is better, the probability is higher. These results could suggest that a consideration of the spatial characteristics form microscopic viewpoint is necessary to understand the commercial gentrification. And these could be used as basic data for a gentrification diagnostic and management system, which can predict gentrification from the view point of business-type-change on the basis of a parcel.

• Journal of Korean Physical Therapy Science
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• v.19 no.2
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• pp.63-71
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• 2012

Purpose : This study aimed to acquire a basic knowledge about lumbar stability and inquire into exercise approach of pressure biofeedback unit for lumbar stability. Methods : This study was composed with reviewed theory of lumbar stability and several books and articles for exercise using pressure biofeedback unit. Results : The stability of lumbar should work symmetrical with passive, active, control subsystem in neutral zone, and local muscles should be using for stability. Especially, selective using of transverse abdominis work for lumbar stability importantly. The control of using pressure biofeedback unit may important not only examination but treatment. Conclusion : The stability of lumbar need co-contraction of specific local muscle and training for timing as well as using pressure biofeedback unit for accurate control may use for examination and therapedic approach.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.211-220
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• 2023

Surface electromyography (sEMG) is a noninvasive method used to capture electrically muscle activity, which can be easily measured even during exercise. The basic unit of muscle activity is the motor unit, and because an sEMG signal is a superposition of motor unit action potentials, analysis of muscle activity using sEMG should ideally be done from the perspective of motor unit activity. However, conventional techniques can only evaluate sEMG signals based on abstract signal features, such as root-mean-square (RMS) and mean-power-frequency (MPF), and cannot detect individual motor unit activities from an sEMG signal. On the other hand, needle EMG can only capture the activity of a few local motor units, making it extremely difficult to grasp the activity of the entire muscle. Therefore, in this study, a method to visualize the activities of motor units in a single-channel sEMG signal by relocating wavelet coefficients obtained by redundant discrete wavelet analysis is proposed. The information obtained through this method resides in between the information obtained through needle EMG and the information obtained through sEMG using conventional techniques.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.211-221
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• 2023

This study was conducted as a basic study for the selection of tags suitable for logistics management in the palletized unit-load unit and the development of various technologies to activate the palletized unit-load shipment of agricultural products through local APCs. Three types of passive RFID tags of UHF 900 MHz and one type of active RFID tag of 2.4 GHz band designed and manufactured through this study were used to analyze the receiving strength according to the tag's attachment location and distance of the palletized unit-load of agricultural products. In the passive RFID tag, there was a large difference in receiving strength by the tag's attachment location and a large amount of data loss depending on the distance within 30 m, whereas, in the active RFID tag, it was superior to the passive tags in terms of both receiving strength and data loss. Therefore, active tags are desirable from the perspective of multiple identification of warehouses with large spaces in relation to the application of RFID tags for palletized unit-loads of agricultural products, but the development of low-power technologies such as software wakeup power management as well as hardware to minimize battery power consumption is necessary.

• Journal of The Korea Institute of Healthcare Architecture
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• v.30 no.1
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• pp.7-17
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• 2024

Purpose: This study is to present basic data and standards for calculating the space composition and area required when planning a neonatal intensive care unit. Methods: Review domestic and foreign facility standards and regulations related to the current neonatal intensive care unit, select a regional neonatal intensive care center designated by the Ministry of Health and Welfare as a case hospital, and organize a space program for the construction plan of the neonatal intensive care unit through analysis of characteristics such as facility size and function composition. Results and Implications: The size, facility area, and detailed room composition characteristics of the neonatal intensive care unit in Korea were confirmed, and essential rooms and appropriate areas were derived when planning the construction of the neonatal intensive care unit. Korea's legal facility standards related to neonatal intensive care units are lower than the actual hospital status and overseas standards, and the facility standards of the medical law need to be improved.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.6
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• pp.487-497
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• 2018

Water quality improvement processes for stagnant area consist mainly of technologies applying vegetation and artificial water circulation, and these existing technologies have some limits to handle pollution loads effectively. To improve the purification efficiency, eco-friendly technologies should be developed that can reinforce self-purification functions. In this study, a multi-functional floating island combined with physical chemical biological functions ((1) flotation and oxidization using microbubbles, (2) vegetation purification and (3) bio-filtration with improved adsorption capacity) has been developed and basic experiments were performed to determine the optimal combination conditions for each unit process. It has been shown that it is desirable to operate the microbubble unit process under conditions greater than $3.5kgf/cm^2$. In vegetation purification unit process, Yellow Iris (Iris pseudacorus) was suggested to be suitable considering water quality, landscape improvement and maintenance. When granular red-mud was applied to the bio-filtration unit process, it was found that T-P removal efficiency was good and its value was also stable for various linear velocity conditions. The appropriate thickness of filter media was suggested between 30 and 45 cm. In this study, the optimal design and operating parameters of the multi-functional floating island have been presented based on the results of the basic experiments of each unit process.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.131-135
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• 2006

Many alternatives on the residential open building have been researched for corresponding high flexibility and possibility of remodeling in Korea as well. However, existing researches only dealt with two-dimensional floor plan. All buildings as well as apartment housing must have been examined various spatial aspect, three-dimensional not two-dimensional. It will examine basic method of three-dimensional flexible unit system to add to three-dimensional usage method overcoming these limitations. The purpose of this study is to propose the system of three-dimensional residential open building in Korea after examining possibility of flexibility of residential open building in 1.5 times of existing floor height.