• 한국생산제조학회지
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• 제9권3호
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• pp.150-159
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• 2000

In-process diagnosis of the cutting state is essential for the automation of manufacturing systems. Especially when the cutting process becomes unstable it induces self-exited vibrations a frequent case of poor tool life rough surface finish damage to the workpiece and the machine tool itself and excessive down time. To ensure that the cutting process main-tains stable it is highly desirable to have the capability of real-time. To ensure that the cutting process main-tains stable it is highly desirable to have the capability of real-time monitoring and controlling chatter. This paper describes the detection method of chatter vibration using cutting force in turning process. In order to detect a chatter vibra-tion the dynamic fluctuation of radial force is analyzed since this components is sensitive to the chatter. The envelope sig-nal of radial force has been calculated by the use of FIR Hilbert transformer and it was useful to classify the chatter signal from the dynamically unstable circumstances. It was found that the mode and the mode width were closely correlated with the chatter amplitude was well. Finally back propagation(BP) neural network have been applied to the pattern recognition for the classification of chatter signal in various cutting conditions. The validity of this systed was confirmed by the experiments under the various cutting conditions.

• 대한후두음성언어의학회지
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• 제13권2호
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• pp.164-172
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• 2002

The role of botulinum toxin as a therapeutic agent is expanding rapidly in otolaryngology. Botulinum toxin is a protease that blocks the release of acetylcholine from nerve terminals. Its effects are transient and nondestructive, and largely limited to the area in which it is administered These effects are also graded according to the dose, allowing for individualized treatment of patients and disorders. Botulinum toxin has been used primarily to treat disorders of excessive or inappropriate muscle contraction. In the field of otolaryngology, these include spasmodic dysphonia, oromandibular dystonia, and blepharospasm, vocal tics and stuttering, cricopharyngeal achalasia, various tremors and tics, hemifacial spasm, temporomandibular joint disorders and a number of cosmetic applications. Botulinum toxin treatment has recently begun to show some benefit in the control of pain from migraine and tension headache. It may also prove useful in the control of autonomic dysfunction, as in Frey syndrome, sialorrhea, and rhinorrhea. In over 20 yews of use in humans, botulinum toxin has accumulated a considerable safety record, and in many cases represents relief for thousands of patients unaided by other therapy.

• 대한인간공학회지
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• 제29권2호
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• pp.211-216
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• 2010

Fire service personnel and ambulance paramedics suffer musculoskeletal disorders as they lift and carry patients while performing Emergency Medical Services (EMS). The objective of the current study was performed to examine the association between working environment and musculoskeletal disorders of 119 paramedics and to analysis the EMS activities for them through basic survey (including task characteristics, risk factors, symptoms and illnesses). Observational job analysis of EMS activities indicated the squatting posture during first-aid performed on floor and the abrupt use of force during carrying heavy load including stretcher with patients on as hazard factors, and excessive low back twisting and bending during stairway transfer was observed. In addition, work-physiological assessment revealed various but rather high lumbar muscle usage rate among the study subjects, being 14.6~32.8% compared with Maximum Voluntary Contraction (MVC) during patients transfer work. Resting heart rate showed 65/min, on the other hand, heart rate on mobilization indicated maximum 124~156/min. Therefore, the results of analysis to the EMS activities, rescuer activities and medical tasks were accompanied with high possibility of accident and musculoskeletal disorders. Also, EMS activities indicated high muscle fatigue and energy consumption, and accumulated muscle fatigue with during continued work.

• Nuclear Engineering and Technology
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• 제41권1호
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• pp.39-52
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• 2009

Theory-based models and high performance simulations are briefly reviewed starting with atomistic methods, such as Electronic Structure calculations, Molecular Dynamics, and Monte Carlo, continuing with meso-scale methods, such as Dislocation Dynamics and Phase Field, and ending with continuum methods that include Finite Element and Finite Volume. Special attention is paid to relating thermo-mechanical and chemical properties of the fuel to reactor parameters. By inserting atomistic models of point defects into continuum thermo-chemical calculations, a model of oxygen diffusivity in $UO_{2+x}$ is developed and used to predict point defect concentrations, oxygen diffusivity, and fuel stoichiometry at various temperatures and oxygen pressures. The simulations of coupled heat transfer and species diffusion demonstrate that including the dependence of thermal conductivity and density on composition can lead to changes in the calculated centerline temperature and thermal expansion displacements that exceed 5%. A review of advanced nuclear fuel performance codes reveals that the many codes are too dedicated to specific fuel forms and make excessive use of empirical correlations in describing properties of materials. The paper ends with a review of international collaborations and a list of lessons learned that includes the importance of education in creating a large pool of experts to cover all necessary theoretical, experimental, and computational tasks.

• 한국의류학회지
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• 제27권11호
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• pp.1208-1218
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• 2003

The purpose of this study is to examine the expressional characteristics and effects of Diabolism image that appeared in fashion illustration. The concept of evil from ancient times is arranged with more basic pain, unhappiness, breakdown, fear, ignorance, sadness, imperfection, death, disease, and ugliness than it can be understandable in modern society. However, as the concept of evil is included in sacred ground of art and is begun to understand by the ugliness of broad sense, the evil and ugliness were recognized as subordinate concepts which fertilizing beauty. Also, image characteristics of Diabolism in pop culture are taking charge roles that remove visual discordance to decadent and mysterious beauty and trying to find new beauty by presentation of bad-tasted style. The aesthetic and expressional characteristics of Diabolism in modem visual media have something in common which is classified into five shapes: Negative image, Symbolic line and color, Transformation, Devilish shape, and Fantastic image. The Diabolism expressions in fashion illustration since 1980 show the possibility of image expression as a new technical field because they differ from existing expression methods and viewpoints of beauty. Therefore, the practical use of devilish image to express excessive aesthetic sense can expand the extent of image expression.

• Archives of Plastic Surgery
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• 제45권4호
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• pp.319-324
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• 2018

Perforator flaps are becoming increasingly common, and as primary thinning techniques are being developed, the need for secondary contouring of flaps is decreasing. However, many reconstructive flap procedures still incorporate secondary debulking to improve the functional and aesthetic outcomes. Direct excision, liposuction, tissue shaving with an arthroscopic cartilage shaver, and skin grafting are the four major methods used for secondary debulking. Direct excision is primarily applied in flaps where the skin is redundant, even though the volume is not excessive. However, due to the limited range of excision, performing a staged excision is recommended. Liposuction can reduce the amount of subcutaneous tissue of the flap and protect the vascular pedicles. However, the main drawback of this method is its limited ability to remove fibrotic tissues, for which the use of a shaver may be more convenient. The main drawback of using a shaver is that it is difficult to simultaneously remove excess skin. Skin grafting enables the removal of sufficient excess tissue to recover the contour of the normal limb and to improve the color match, facilitating excellent aesthetic results.

• Tribology and Lubricants
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• 제30권5호
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• pp.291-294
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• 2014

Multiple additives can help improve the performance of generally used lubricants. These additives include MoS2, cadmium, chloride, indium, sulfide, and phosphide, which are harmful to both humans and the environment. Thus, researchers in this industry have been trying to reduce the use of these additives by finding alternatives. Nanodiamonds are one of these candidates. Nanodiamond particles are very hard, chemically stable, and highly heat-conductive. This research involved uniformly dispersing nanodiamond particles in marine engine oils via a matrix synthesis method at various concentrations (0, 0.1, 0.3, 0.5, and 1.0 wt). Friction and wear tests involved constant loads on ball-on-disk specimens, where the ball was AISI 51200 steel, the disk was AISI 1020 steel, and the sliding speed was 0.217 m/s. The lowest wear occurred at a suitable concentration of nanodiamonds (0.3 wt). However, excessive amounts of nanodiamonds caused them to act as abrasive debris because of their hardness, which increased the wear amount. The friction coefficient decreased as the nanodiamond concentration increased because their octagonal, almost spherical shape caused them to act as rolling contact elements between two surfaces.

• 한국인터넷방송통신학회논문지
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• 제16권1호
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• pp.183-191
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• 2016

스마트폰의 확산과 더불어 SNS는 눈부시게 성장하고 있다. 그러나 SNS의 사용이 과해짐에 따라 SNS 중독이라는 사회문제가 대두되고 있다. 한편 SNS에 대한 부정적인 인식 때문에 사용자가 SNS를 떠나는 것 역시 문제로 떠올랐다. 이와 같이 SNS의 중독 및 지속사용 모두 SNS의 사용에 있어 중요한 문제이며, 이에 본 연구에서는 기본심리욕구를 원인 변인으로 선정하여 그 영향력을 확인하고자 하였다. Facebook 사용자 204명을 대상으로 한 연구결과 자율성 및 유능성은 Facebook 중독에 유의한 영향을 미쳤으며, 자율성, 유능성 및 관계성은 Facebook 지속사용의도에 유의한 영향을 미치는 것으로 나타났다.

• International Journal of Concrete Structures and Materials
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• 제8권4호
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• pp.315-326
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• 2014

This study evaluates the dosages of Class F fly ash, lithium nitrate and their combinations to suppress the excessive expansion caused by alkali-silica reactivity (ASR). In order to serve the proposed objective, the mortar bar specimens were prepared from (1) four dosages of Class F fly ash, such as 15, 20, 25 and 30 % as a partial replacement of Portland cement, (2) up to six dosages of lithium nitrate, such as lithium-to-alkali molar ratios of 0.59, 0.74, 0.89, 1.04, 1.19 and 1.33, and (3) the combination of lithium salt (lithium-to-alkali molar ratio of 0.74) and two dosages of Class F fly ash (15 and 20 % as a partial replacement of Portland cement). Percent contribution to ASR-induced expansion due to the fly ash or lithium content, test duration and their interaction was also evaluated. The results showed that the ASR-induced expansion decreased with an increase in the admixtures in the mortar bar. However, the specimens made with the both Class F fly ash and lithium salt produced more effective mitigation approach when compared to those prepared with fly ash or lithium salt alone. The ASR-induced expansions of fly ash or lithium bearing mortar bars by the proposed models generated a good correlation with those obtained by the experimental procedures.

• 한국환경과학회지
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• 제19권4호
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• pp.389-397
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• 2010

The in vitro toxicities of three crude oils of the Hebei Spirit were examined on laboratory grown plankton, with a focus on the effects of a dispersant. The specific growth rate of phytoplankton and the mortalities of two zooplankton were measured in response to exposure to various concentrations of water accommodated oil, dispersant or both. The effects of the oils varied among the plankton, but were generally low within the range of the oil concentrations used, with little difference in toxicity among the three oils. Such low toxicity appeared to be associated with weathering of the crude oils. Exposure to the dispersant, however, dramatically increased the mortality of zooplankton, with complete inhibition of phytoplankton growth. No synergistic toxic effect was observed with the crude oil and dispersant combination. A better decision making process could be crafted for future application of dispersant in the event of an oil spill in Korean waters to better protect the marine plankton community from the excessive use of dispersant.