• Journal of the Korea Safety Management & Science
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• v.7 no.2
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• pp.57-64
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• 2005

Prescribed according to the occupational safety and health low noise measurement method was changed to personal sampling in the method to measure an area noise. Such method had the limit which did not evaluated characteristic of sound of occurrence and the place of origin. This study was peformed to establish an engineering remedy of the work-place noise. The subject was a vibration control process of the place of business in Pusan. A simulation program applied for an engineering improvement of the work-place noise. The results were as follows: 1. An noise occurrence level of the work-place before improvement was $88^{\sim}97dB(A)$, We applied an improvement method to be established and were expected to $80^{\sim}l19dB(A)$, 2. The level of the noise-distribution to appear in the place of origin of the work-place before improvement was $90^{\sim}93dB(A)$ but, We executed the simulation after applied an engineering remedy and predicted $80^{\sim}85dB(A)$. A result of the simulation blue part was changed mostly into the dark blue color. The results suggest that simulation program establishes an engineering remedy and is useful to the case to apply.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.191-198
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• 2016

This paper aims to present how to design and implement a multimedia tutorial system for the self-learning French language using Director with additional tools. To implement a multimedia tutorial system we need to design several steps. First, we should choose the level of the users and design tutorial. Second, we should prepare all materials such as sounds, graphics, text and video. Finally, we should implement the selected elements and control the educational software. Due to the nature of the paper, it must emphasize French basic conversation to make environment that be used in each scene and the scene of the context dialog. In view of the fact that the fitness of each content utilization field of multimedia authoring tool is high, it is possible as part of the system sizing process of the manufacturing process, to impart its meaning. This learning-contents are composed of 10 units each situation, and we anticipate there are the several effects of this system on basic French students. This system helps lecturer get French students interested in lessons, and enables learner to learn French of the role of iterative practice by linking image and sound. Also this system helps learners to prepare and review French studying after a lesson and allows leaners to maximize their efficiency. The future of this work is to implement this system on the app.

• Korean Journal of Materials Research
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• v.25 no.10
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• pp.571-576
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• 2015

The effects of coating thickness on the delamination and fracture behavior of thermal barrier coating (TBC) systems were investigated with cyclic flame thermal fatigue (FTF) and thermal shock (TS) tests. The top and bond coats of the TBCs were prepared by electron beam-physical vapor deposition and low pressure plasma spray methods, respectively, with a thickness ratio of 2:1 in the top and bond coats. The thicknesses of the top coat were 200 and $500{\mu}m$, and those of the bond coat were 100 and $250{\mu}m$. FTF tests were performed until 1140 cycles at a surface temperature of $1100^{\circ}C$ for a dwell time of 5 min. TS tests were also done until more than 50 % delamination or 1140 cycles with a dwell time of 60 min. After the FTF for 1140 cycles, the interface microstructures of each TBC exhibited a sound condition without cracking or delamination. In the TS, the TBCs of 200 and $500{\mu}m$ were fully delaminated (> 50 %) within 171 and 440 cycles, respectively. These results enabled us to control the thickness of TBC systems and to propose an efficient coating in protecting the substrate in cyclic thermal exposure environments.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.227-232
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• 2015

Nowadays, there are many innovative products in the pro-audio market thanks to advanced IT technology, DSP is very important technology to process high quality audio signal in SR(Sound Reinforcement) system. Digital audio technology that converged with IT technology can give new user-experience. In this paper, we present a new digital crossover system for active speakers using DSP and network technology. The prototype of crossover module consists of various audio process module such as filters, delay, phase controls and also it provides user to remote monitoring and remote control features by internet connection.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.3
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• pp.119-127
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• 2020

This study was conducted to determine how precooling reduces the subjective reported pain and objective pain and to evaluate the effectiveness of precooling the injection site before administration of local anesthesia in children. Electronic databases (PubMed, Ovid SP, Cochrane Central Register of Controlled Trials) were searched for publications from 1980 to 2020. Studies were screened for titles and abstracts, followed by full-text evaluation of included reports. Six studies were included in this systematic review. The primary outcome evaluated was the pain perception or the subjective pain reported by the child receiving the injection. The secondary outcome evaluated was objective pain evaluated in each study. Among 5 studies that evaluated child reported pain scores on a visual analogue scale (VAS), 4 studies reported lower scores in the precooling group and one study reported a higher VAS score in the precooling group than in children treated with 20% benzocaine topical anesthesia. Among 6 studies that evaluated the pain reaction of children by Sound Eye Motor (SEM) score, 4 studies reported a lower SEM score in the precooling group, one study reported no significant difference between the precooling and control groups, and one study reported higher SEM scores in the precooling group than in children treated with 20% benzocaine topical anesthesia. Within the limits of this systematic review, evidence suggests that precooling the injection site with ice can be an effective adjunct to topical anesthesia in reducing both subjective and objective pain during local anesthesia administration in children.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1674-1680
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• 2009

This paper proposes an autonomous fault determination, fault zone isolation and fault restoration strategy based on the ethernet communication as a new attempt to solve the problem the of the existing central control method. In proposed method, The FRTU(Feeder Remote Terminal Unit)s on the feeder determines autonomously where the faulted zone is by exchanging the voltage and current information with neighbor FRTUs based on the network communication, and then separates the faulted zone in an nil-voltage status to make the protective device to reclose successively. In particular, the minimization of outage time and relational load balancing is archived by each interconnection switch which determines autonomously the load zone to be allocated among those zones after the sound outage zones was separated individually. Finally, to show effectiveness of the proposed fault restoration strategy, the several fault cases are simulated for the test distribution system, and the load balancing index of the proposed solution is compared with all of feasible solutions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.97-103
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• 2008

Recently, it is increased to apply sensorless drive for BLDC (Brushless DC) motor to household electrical appliances, especially in the refrigerators and air conditioners, to reduce the cost and the acoustic noise by the operation and to make their functions more comfortable for human beings. In this paper, low-cost sensorless drive for BLDE motor is implemented by random PWM (Pulse Width Modulation). The experimental results show that the electromagnetic noise was reduced and the sound quality was improved by BLDC motor sensorless random PWM Control.

• Journal of the Korea Institute of Building Construction
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• v.16 no.1
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• pp.87-96
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• 2016

More than half of Korea's urban population currently lives in multi-unit dwellings. This particular residence structure inevitably positions the living spaces of residents in close proximity to one another. Because of this proximity, the sounds of a particular household will transfer to other residents' units creating conflict between tenants. Efforts to alleviate this problem have been made in both the public and private sector. A prominent method of noise analysis between living units has been to make an actual sound measurement and obtain qualitative measurements from questionnaires. Although this method has been most widely used, such analysis requires a large amount of human effort and time. In addition, the questionnaire method fails to provide the objective information needed to accurately assess the noise situation. To overcome the inadequacies of this previous method, this study seeks to evaluate the applicability of an acoustic simulation method. Three types of living noises were analyzed to assess the noise levels passed between multi-unit dwellings. The acoustic simulation method was found to be more economical, efficient, and adaptable in information processing. The results of this study can be further applied to design and control living-noise through procedures such as acoustic absorption or space redesign.

• Journal of Environmental Impact Assessment
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• v.9 no.1
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• pp.87-98
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• 2000

The costs of solid waste management have continued to increase. Stricter environmental regulations have been applied to waste management units. Future integrated solid waste management should be balanced between source reduction, recycling, energy recovery, and land disposal. To achieve more balanced solid waste management programs, more local governments must adopt diversion and recycling goals and finance to meet those goals. The hierarchy of integrated solid waste management must be enforced in a manner that is flexible enough to allow local governments to implement waste management facilities that match the communities' ability to pay for them. In establishing a hierarchy of integrated solid waste management, local governements have difficulties in implementing source reduction and recycling because of a lack of local control and inability to pay for new facilities. Integrated solid waste management involves selecting compatible options for facilities to manage the collection, recovery of energy and materials(transformation), and disposal of solid wastes efficiently. Waste Collection, transformation, and disposal must support source reduction and recycling activities.

• Journal of Biomedical Engineering Research
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• v.14 no.2
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• pp.125-136
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• 1993

The study of Cochlear biomechanics is to clearly define three biomechanical principles of the Cochlea : Activity, Nonlinearity and Feedback. In this article, the Cochlea is linearly and actively modelled in one dimensional time domain. The sharp tunning of the Basilar Membrane displacement is shown when the amplifying activity of hair cells is added to the model. The amplified energy of the travelling displacement wave is emitted throughout the Cochlear fluid, so that the model becomes unstable. A new technique is introduced to reduce strong echos fro the Helicotrema. It makes the model less unstable. Both pure and click tones are used as input stimuli onto the ear durm. When the model is normal, the click response of the model shows that the backward emission of the amplified fluid pressure has mainly the echos from the Helicotrema. However, when the linear and active model is assumed to be abnormal, that is, some of hair cells are damaged not to produce the active process, the effect of the hair cell damage is resulted in the Oto-acoustic emission. The frequency response of the abnormally emitted sound pressure shows that the Oto-acoustic emission has the information about the characteristic frequency of the damaged hair cell. The main aim of this paper is to demonstrate the active biomechanics of the Chchlea in the time domain.