• Journal of the Korean Magnetics Society
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• v.23 no.3
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• pp.83-88
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• 2013

The soft magnetic Fe-Si-Cr flakes with the thickness of about 1 ${\mu}m$ were annealed at 500 and $700^{\circ}C$ for 1 h, and the composite sheets for electromagnetic wave noise absorber available for quasi-microwave band were fabricated by using these annealed flakes and polymer. Further the power loss characteristics of the composite sheets was investigated to clarify the annealing effect on electromagnetic wave absorption properties. The power loss decreased in the frequency range of several GHz when the annealed flakes were used as compared to the sheet using the as-milled FeSiCr alloy flakes. Moreover the sheets using annealed flakes exhibited lower value of real and imaginary part of complex permeability. These inferior electromagnetic wave absorption properties of the composite sheets using annealed alloy flakes were considered to be obtained by the enhanced eddy current effect upon annealing-induced recovery of microstructure and resulted low complex permeability.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.1
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• pp.22-29
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• 2006

We demonstrate highly manufacturable Multi-channel Field Effect Transistor (McFET) on bulk Si wafer. McFET shows excellent transistor characteristics, such as $5{\sim}6 times higher drive current than planar MOSFET, ideal subthreshold swing, low drain induced barrier lowering (DIBL) without pocket implantation and negligible body bias dependency, maintaining the same source/drain resistance as that of a planar transistor due to the unique feature of McFET. And suitable threshold voltage ($V_T$) for SRAM operation and high static noise margin (SNM) are achieved by using TiN metal gate electrode.

• Journal of computational fluids engineering
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• v.19 no.2
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• pp.66-71
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• 2014

Aerodynamic design of a vehicle has very important meaning on the fuel economy, dynamic stability and the noise & vibration of a moving vehicle. In this study, the correlation of aerodynamic effect between two model vehicles moving inline on a road was studied with the basic SAE model vehicle. Drag and lift are two main physical forces acting on the vehicle and both of them directly effect on the fuel economy and driving stability of the vehicle. For the research, the distance between two vehicles is varied from 5m to 30m at the fixed vehicle speed, 100km/h and the side-wind was assumed to be zero. The main issue for this numerical research is on the understanding of the interaction forces; lift and drag between two vehicles formed inline. From the study, it was found that as the distance between two vehicles is closer, the drag force acting on both the front and rear vehicle decreases and the lift force has same trend for both vehicle. As the distance(D) is 5m, the drag of the front vehicle reduced 7.4% but 28.5% for the rear-side vehicle. As the distance is 30m, the drag of the rear vehicle is still reduced to 22% compared to the single driving.

• The Journal of Korean Medicine
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• v.25 no.3
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• pp.160-168
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• 2004

Background and Objectives: Tinnitus is on the increase due to the increase in the elderly population, industrial pollution and noise pollution. This symptom is especially marked in patients with a hearing problem and the relationship between cause, mechanism and treatment is poorly understood. The characteristics of tinnitus and other hearing problems are well brought out using an animal model with salicylate ototoxicity. Therapeutic effects of Uncariae Ramulis and Testudinis Plastrum were expected in tinnitus and hearing problems; therefore we experimented on an animal model with salicylate ototoxicity. Salicylate is one of the most commonly prescribed drugs, although it has been recognized that salicylate induces hearing loss and tinnitus reversibly. The purpose of this study was to find the therapeutic effects of this by the morphologic study using salicylate ototoxicity. Materials and Methods : Twelve healthy Sprague-Dawley rats were divided into three groups: normal, control and sample. The sample group was treated with the extract of Uncariae Ramulis and Testudinis Plastrum (1cc/100g, once a day for 6 days). Then, to induce the salicylate ototoxicity in the control and sample groups, rats were injected intraperitoneally with sodium salicylate (500mg/kg). We observed the morphologic changes in the cochlea of the rats every 2, 3, 4 and 5 hours after injection. Results : The outer hair cells showed marked changes. Vacuolization formed in the cuticular plate and the endoplasm of the control group. The endoplasm and the cuticular plates of the sample group after 2 hours were similar to the control group, but the cuticular plates of the sample group observed after 3, 4 and 5 hours were not similar. Conclusions : The results suggest that an extract of Uncariae Ramulis and Testudinis Plastrum has therapeutic effects on an animal model with salicylate ototoxicity.

• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.89-96
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• 2015

To reduce noise inside an elevated railroad station, the vibration of the station structure should be lowered, and to establish more effective anti-vibration measures it is required that, reflecting the track-bridge-structure interaction, the transfer characteristics of vibration induced by a train is well identified. In this paper, the current status of domestic railroad stations is classified, and the vibration transfer characteristics is analyzed via measurement data from representative elevated stations. From the analysis results on the measurement data, in transferring vibration from the track to the structure, remarkable vibration reduction in higher frequency range is observed, and, in some stations, amplified response characteristics in lower frequency range is identified. Also, for stations with floating track system or TPS type, relatively greater reduction in transferred vibration is observed.

• Journal of Preventive Medicine and Public Health
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• v.24 no.1 s.33
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• pp.45-56
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• 1991

The history of occupational health in Korea s covered the era of the Republic of Korea after the Liberation from the Japanese colonialism. But the number of Korean workers exceeded about 2 millions at the times of liberation in 1945, so that it is expected that many occupational health problems inflicted Korean workers under the Japanese colonialism. The authors reviewed medical literatures, administrative documents, and other available data which were published under the colonial state, and collected things which had reference to the health status of Korean workers. The results were as follows : 1. Nutritional status of Korean workers was supposed to be inferior to that of general population, some students, and poor inhabitants in a remote mountain villages. 2. It was supposed that the constitution of Korean workers was near lower limit of average build of contemporary Koreans. 3. The accidents rate in mines was significantly high but decreasing year after year, and the most important cause of accidents was the fall of roof in the mine. The medical facilities and equipments for miners were supposed to be not sufficient in the mines and workshops. 4. Some occupational disease including silicosis, noise-induced hearing impairment, and decompression disease were known. But, overall incidence or prevalence of these diseases could not be identified. 5. On the whole, the fatalities of acute infectious diseases of Korean workers were higher than those of Japanese inhabitants in Korea and Korean inhabitants. The prevalence of pulmonary tuberculosis of Korean workers was increasing with every passing year. 6. The medical personnels and facilities were so deficient that most Korean workers were out of adequate medical use. We discussed only a part of the health status of Korean workers under the Japanese colonialism, so it would be necessary to have a better grasp of details of occupational health policy and health status in the era of afflicting.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.1
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• pp.18-22
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• 2002

Background and Objectives : It has been pointed out that alcohol intake in human beings induces changes in voice register and maximum phonation time. These changes supposedly result from injection of the vibratory vocal folds. The purpose of this study was to clarify the voice changes associated with alcohol intake and the changes of laryngeal mucosa. Materials and Methods : The subjects included 29 volunteers, including 20 men and 9 women ranging in age from 22 to 31 years. Alcohol intake was accomplished by oral administration of 23% soju 1 bottle (255cc). Serum alcohol concentration levels were evaluated hourly for 3 h after ingestion of alcohol. Seven measurements were performed at pre-alcohol intake and post-alcohol intake hourly : fundamental frequency, jitter, shimmer, noise to harmonic ratio as the acoustic analysis, maximal phonation time, mean flow rate, and subglottal pressure as the aerodynamic analysis. The changes of laryngeal mucosa were evaluated by flexible laryngoscope at each measurement. Results : By comparing the acoustic and aerodynamic data and laryngeal mucosa before and after alcohol intake, there were not remarkable changes (p>0.05). Conclusion : The voice and laryngeal mucosa have not remarkably changed according to alcohol concentration in this study. Furthermore studies on the voice change induced by multiple alcohol concentrations are required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5280-5287
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• 2014

This paper proposes a method in which classes are grouped as a hierarchical tree structure for the effective classification of the Raman spectra. As experimental data, the Raman spectra of 28 chemical compounds were obtained, and pre-treated with noise removal and normalization. The spectra that induced a classification error were grouped into the same class and the hierarchical structure class was composed. Each high and low class was classified using a PCA-MAP method. According to the experimental results, the classification of 100% was achieved with 2.7 features on average when the proposed method was applied. Considering that the same classification rates were achieved with 6 features using the conventional method, the proposed method was found to be much better than the conventional one in terms of the total computational complexity and practical application.

• Journal of Sensor Science and Technology
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• v.12 no.2
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• pp.88-94
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• 2003

Electromyogram (EMG) is the bioelectric signal induced by motor nerves. Analyzing EMG with the movement produced by muscle contraction, we can provide input commands to a computer as a man-machine interface as well as can evaluate the patient's motional abnormality. In this paper, we developed an integrated miniaturized device which acquires and transmits the surface EMG of an interested muscle. Developed system measures $60{\times}40{\times}25mm$, weighs 100g. Using an amplifier circuitry on the electrodes and the radio frequency transmission, the developed system dispenses with the use of cables among the electrodes, amplifier, and the post processing system (personal computer). The wiring used in conventional systems can be obstacle for natural motion and source of motion artifacts. In results, the developed system improves not only the signal-to-noise ration in dynamic EMG measurement, but also the user convenience. We propose a new human-computer interface as well as a dynamic EMG measurement system as a possible application of the developed system.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.17-24
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• 2014

Blind algorithms designed to maximize the probability that constant modulus errors become zero carry out some summation operations for a set of constant modulus errors at an iteration time inducing heavy complexity. For the purpose of reducing this computational burden induced from the summation, a new approach to the estimation of the zero-error probability (ZEP) of constant modulus errors (CME) and its gradient is proposed in this paper. The ZEP of CME at the next iteration time is shown to be calculated recursively based on the currently calculated ZEP of CME. It also is shown that the gradient for the weight update of the algorithm can be obtained by differentiating the ZEP of CME estimated recursively. From the simulation results that the proposed estimation method of ZEP-CME and its gradient produces exactly the same estimation results with a significantly reduced computational complexity as the block-processing method does.