• Proceedings of the KSR Conference
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• 1999.05a
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• pp.143-150
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• 1999

The vibration signals of driving parts of electric train are distorted its signal patterns due to the impact components, which occurs when wheel passes rail joints. An elimination method of the impact components is investigated using adaptive signal processing technique in this study. The result shows that adaptive interference canceling method seems to be more effective than line enhancement technique. The application of adaptive interference canceling method to the signal measured at bogie shows that the extractions of the signals of driving parts of traction motor, reduction gear, and axle bearing are successful. Therefore, only the signals of bogie, which is the place to attach an accelerometer easily, is sufficient for the fault diagnosis and the safety evaluation of electric train. Also, adaptive interference canceling method can be applicable to evaluate the performance of vibration isolation between bogie and car body and to investigate the characteristics of indoor sound.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.2
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• pp.77-82
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• 2011

In this paper, we investigate source separation algorithms for stereo audio mixed using amplitude panning method. This source separation algorithms can be used in various applications such as up-mixing, speech enhancement, and high quality sound source separation. The methods in this paper estimate the panning angles of individual signals using the principal component analysis being applied in time-frequency tiles of the input signal and independently extract each signal through directional filtering. Performances of the methods were evaluated through computer simulations.

• Journal of Family Resource Management and Policy Review
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• v.5 no.2
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• pp.59-67
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• 2001

Pu-lei is a well-known translator in Chinese literature. He had delivered his experience, knowledge and paternal love to his son who was studying abroad, by hundreds of letters from 1954 to 1966. These letters are appreciated as the perfect expression for paternal love and concerns. Although he had experienced both cultures of the West and the East, his lessons for son are rooted in the oriental‘sprit training’. What he emphasized in his letters is that one should put sound personality first than merely enhancing abilities. Especially, he valued the recreation from meditation and living up to one's belief. Furthermore, he had taught his son to observe the properties, to manage time, and pride of his country and patriotism. The modern family education has overlooked the enhancement of human nature. The egoistic and jaundiced parental love and over-protectiveness led the disorder and the absence of morality today. In this point, the lessons from Pu-lei's letter will give us important suggestions.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.97-104
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• 2008

This study was intended to evaluate the permeable performance through a change of reinforcing materials, curing condition, durability evaluation and permeability test, and to select the reinforcing material which could reduce the durability and water tightness from it, as the study for considering how the change of the outside's environment factors that the concrete structure actually contacted with impacted the concrete's durability especially the permeability by referring to such the background of the study. Accordingly, it was judged that evaluating the permeability by considering the severe environment condition where the concrete structure was placed in was more reasonable than measuring the existing permeability coefficient conducted in the sound state for the permeability evaluation of actually-used concrete structure. In this study, it also could be known that the specimen of hybrid fiber reinforced concrete which mixed the long and short steel fiber was the most effective for water tightness enhancement in severe environmental conditions.

• Science of Emotion and Sensibility
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• v.17 no.1
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• pp.53-62
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• 2014

Despite the huge potential of the practical application of emotion recognition technologies, the enhancement of the technologies still remains a challenge mainly due to the difficulty of recognizing emotion. Although not perfect, human emotions can be recognized through human images and sounds. Emotion recognition technologies have been researched by extensive studies that include image-based recognition studies, sound-based studies, and both image and sound-based studies. Studies on emotion recognition through facial expression detection are especially effective as emotions are primarily expressed in human face. However, differences in user environment and their familiarity with the technologies may cause significant disparities and errors. In order to enhance the accuracy of real-time emotion recognition, it is crucial to note a mechanism of understanding and analyzing users' personality traits that contribute to the improvement of emotion recognition. This study focuses on analyzing users' personality traits and its application in the emotion recognition system to reduce errors in emotion recognition through facial expression detection and improve the accuracy of the results. In particular, the study offers a practical solution to users with subtle facial expressions or low degree of emotion expression by providing an enhanced emotion recognition function.

• Journal of East-West Nursing Research
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• v.6 no.1
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• pp.46-54
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• 2001

This study was conducted to identify the effectiveness of meridian acupressure for enhancement of post operative bowel movement to the patient with absolute bed rest who having surgery under general anesthesia. This study used a qusai experimental, nonequivalent control group post test only design. This subject were 44 patients, 22 for the experimental and 22 for the control group, who were admitted at KyungHee University hospital, neurosurgical unit A and B ward, assigned by matched sample by the name of operation who having microvascular decompression and laminectomy. Date were collected from May 1, 2001 to June 30, 2001 by auscultation, self report and by using 7 point face scale. The recovery of bowel sound were measured every 4 hours until gas out for 1 minute auscultation on lower abdomen after 4 hours having surgery. The time of gas out were measured by self report, the severity of nausea were measured every 4 hours for 7 point face scale and also the degree of satisfaction of nursing care were measured after 2 days having surgery with same scale. Data were analyzed with $X^2$, t-test, repeated measures ANOVA and ANOVA. The result of this study were as follows; 1. The experimental group which were implemented with meridian acupressure showed shorter time the recovery of bowel sound after having surgery than control group(t=-5.112, p=.0001). 2. The experimental group which were implemented with meridian acupressure showed shorter time of gas after having surgery than control group(t=-4.010, p=.0001) 3. The experimental group which were implemented with meridian acupressure showed decreased level of nausea score according to time interval than control group(F=21.995, p=.0001). 4. The experimental group which were implemented with meridian acupressure showed higher the degree of satisfaction of nursing care than control group(t=-4.010, p=.0001). These finding indicate that a meridian acupressure could be a effective nursing intervention for enhancement of post operative bowel movement to the patient with absolute bed rest who having surgery under general anesthesia.

• Safety and Health at Work
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• v.10 no.1
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• pp.109-113
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• 2019

Background: In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift. Methods: This case-control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with ${\alpha}=0.05$. Results: The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p < 0.0001, p < 0.0001). Conversely, age and body mass index had no significant influence on cortisol concentration (p = 0.360, p = 0.62). Conclusion: Based on the obtained results, increasing SPL will lead to enhancement of serum cortisol concentration. Given that cortisol concentration varies while workers are exposed to different SPLs, this hormone can be used as a biomarker to study the effect of noise-induced stress.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.5
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• pp.321-327
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• 2016

This paper presents the application of airfoil impeller for enhancement of aerodynamic performance of a high speed centrifugal fan. Three airfoil impellers are proposed, considering the maximum thickness and the location of maximum thickness of the airfoil. C4 airfoil thickness distribution is applied to the three airfoil impellers. The impellers are evaluated using CFD (computational fluid dynamics) and suction power test. From the results, it is confirmed that flow separations on the pressure side of the impeller blades and the pressure side of diffuser blades are reduced when airfoil blade is applied to the impellers. It is also confirmed that with the centrifugal fan having airfoil impellers, there is an increase in fan efficiency by approximately 3% and reduction in specific sound level by approximately 1.3 dB(A).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.5
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• pp.25-37
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• 2010

This study is aimed at enhancing mobility rights for the transportation underprivileged that has been made light of relatively compared to normal people. In order to do this, we've suggested having ITS (Intelligent Traffic System) built and improving satisfaction through the test operation of its main system. The existing sound signal device for the visually handicapped has one problem with managing it. Because, the people in charge of it had to visit each problematic site directly to maintain and fix some problems every time it was out of order. Moreover, it couldn't provide sustainable services about voice guidance and the visually handicapped had to control it by either confirming the location of buttons that were installed on the pillar of traffic light and then pressing one of them or using a remote controller on their own. In order to improve such inconveniences, we have created a new typed sound signal device for the visually handicapped by applying the cutting-edge wireless technology based on ergonomics considering actual road situations. Such technology enables it report the status of signal device and light to them by using its voice guidance system automatically every time they have access to it. Additionally, we've already introduced it to a couple of test areas and then known the fact that they recognized traffic situation more conveniently and safely compared to the existing sound signal device. That is above average in terms of satisfaction. In addition to that, we've provided LTS (Location Tracking System - Location-based service intended for elementary students) by utilizing the existing wireless infrastructure and founded the fact that about 87% of their parents were satisfied with the service based on LTS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1472-1479
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• 2003

An attempt to reduce supersonic jet noise is carried out by using two steady microjets in a round jet. The jet is issued from a round sonic nozzle with an exit diameter of 10 mm. Two micro-nozzles with an inside diameter of 1 mm each are installed on the exit plane at an angle of 45 relative to the main jet axis. Far-field noise was measured at 40 diameters off the jet axis. The angle between a microphone and the jet axis is 30 or 90$^{\circ}$. For an injection rate of 4-6% of the main jet, screech tones were completely suppressed by the microjets. The reduction in the overall sound pressure levels were 2.4 and 2.7 dB for 90 and 30 measuring directions, respectively. However, the enhancement of mixing/spreading of the jet by the microjet was negligible. The reduction of noise is probably due to distorted shock cell structures and/or deformed large scale vortical structures by the microjets.