• Journal of Legislation Research
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• no.55
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• pp.7-56
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• 2018

This paper deals with the legal meaning and issues of street performances. The key elements in the legal sense of street performances (or artistic performances) are 'public places' and 'artistic activities'. Therefore, as far as belongs to "artistic activities in public places", we can call them in principle as street performances regardless of its level of art, whether they are paid or not, size of performances or genre of artistic activities. Street performances are a way for anyone to freely participate and enjoy art by being performed on open places. In addition, street performances can be seen as more popular and democratic artistic acts than mainstream art culture in that anyone can become street performers. Although street performances are in vogue and becoming a universal cultural phenomenon, they do not appear to be legally organized yet. However, we don't have to strictly regulate street performances on the grounds that they are something different and special. Instead, they should let their street performances be freely performed and enjoyed in accordance with the constitutional law that guarantees the freedom of art or the freedom of artistic expression. Of course, it is necessary to modify the relevant laws on key issues raised regarding street performances. Finally, for street performances to be well established as cultural phenomenon, it should be harmonized that efforts to observe the law and orders by street performers, mature rituals and cultural tolerances of citizens who enjoy street performances, and efforts to realize the purpose of cultural countries and to promote street performances by governments.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.66-74
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• 2021

The objective of this study is to evaluate the practical application potential and limitations of the modified fly ash(MFA) by vibration grinding as a partial replacement of ordinary portland cement(OPC). The test parameters investigated were the replacement level of fly ash(FA) and FA for OPC, varying from 10% to 40%, and curing temperatures of 5, 20, and 40℃. The various characteristics(including slump, air content, bleeding, setting time, compressive strength development, and hydration products) of MFA concrete were measured and then compared with those of the concrete with conventional FA. Test resul ts showed that the MFA prefers to FA in reducing the bl eeding of fresh concrete and enhancing the compressive strength gain at an early age. The compressive strength ratios between MFA and FA concrete specimens at an age of 1 day were 135%, 146%, and 111% at the curing temperatures of 5, 20, and 40℃, respectively. The corresponding ratios at an age of 28 days were approximately 110%, regardless of the curing temperatures. The X-ray diffraction analysis also revealed less calcium hydroxide products in MFA pastes than in FA pastes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.5
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• pp.357-371
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• 2023

In cable tunnel construction using TBM, the vertical shaft is an essential structure for entrance and exit of TBM equipment and power lines. Since a shaft penetrates the ground vertically, it often encounters rock mass. Blasting or rock splitting methods, which are mainly used to the rock excavation, cause public complaints due to the noise, vibration and road occupation. Therefore, mechanical excavation using vertical shaft excavation machine are considered as an alternative to the conventional methods. However, at the current level of technology, the vertical excavation machine has limitation in its performance when applied for high strength rock with a compressive strength of more than 120 MPa. In this study, the potential utilization of waterjet technology as an excavation assistance method was investigated to improve mechanical excavation performance in the hard rock formations. Rock cutting experiments were conducted to verify the cutting performance of the abrasive waterjet. Based on the experimental result, it was found that ensuring excavation performance with respect to changing in ground conditions can be achieved by adjusting waterjet parameters such as standoff distance, traverse speed and water pressure. In addition, based on the relationship between excavation performance, uniaxial compressive strength and RQD, it was suggested that excavation performance could be improved by artificially creating joints using the abrasive waterjet. It is expected that these research results can be utilized as fundamental data for the introduction of vertical shaft excavation machines in the future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.103-114
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• 2023

Objectives: This study was conducted to evaluate hand-arm vibration (HAV) exposure levels due to the use of power hand tools and to evaluate the determinants in the automobile assembly process. Methods: The exposure level to HAV was evaluated for 30 work lines in five assembly processes (body, engine, chassis, door, and design) that use air-powered tools and battery-powered tools and operate in circulation for two hours. The 2-hr equivalent energy vibration acceleration, A (2), of the task was measured. The 8-hr equivalent energy vibration acceleration, A (8), was estimated in consideration of the number of tasks that can be performed per day by each process. In addition, a survey on the working environment was conducted with workers exposed to vibration. Results: The geometric mean of the HAV exposure level, A (2), for a total of 30 tasks was 2.51 m/s², and one case was 10.30 m/s², exceeding TLV (2hr). The HAV exposure level of A (8) was evaluated from 1.03 m/s² to 5.36 m/s². A (2) showed a statistically significant difference (P<0.01) for each process, and the chassis process (GM=3.90 m/s²) was the highest. The larger the tool size and the longer the tool length, the higher was the vibration acceleration when using a battery-powered tool than an air-powered tool (P<0.01). Battery-powered tool users showed higher dissatisfaction on all items than did air-powered tool users. Conclusions: As a result of this study, it is necessary to implement a program to reduce the HAV exposure levels.

• Tuberculosis and Respiratory Diseases
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• v.49 no.3
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• pp.343-352
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• 2000

Backgrounds : Respiratory care for patients in intensive care units (ICUs) has been performed mainly by nurses in Korea. However, the current status of respiratory care in the Korea ICUs is not well known. Respiratory care and the methods of delivery in ICUs were surveyed. Method : A confidential questionnaire was distributed to the head nurses working the ICUs at 117 hospitals in Korea. One hundred hospitals returned the questionnaires, for a response rate of 85%. The hospitals were divided into three groups : Main university hospitals (MUH), university associated hospitals (UAH), and general hospitals (GH) Result : Eighteen units of 66 units in MUH and 35 units of 58 units in GH were organized as a general ICUs. The percentage of ICUs with full-time doctors was 47.1%. The nurses usually delivered respiratory care spending from 1 to 4 h during their 8 h of working time. Although the respondents felt that respiratory care should be delivered by trained respiratory therapists, these therapists were not found at the hospitals. Most of the units performed percussion, tracheal suctioning, and positional changes. However, vibration and IPPB were less frequently performed in GH. Among oxygen supply apparatus, venturi mask and T-piece were not frequently used in GH. GH applied a noninvasive ventilator mode less frequently than MUH and UAH. The percentage of Swan-Ganz catheter monitoring was only 21.4% in GH. Conclusion : Respiratory care for patients in the Korean ICUs was provided by nurses on the whole. In addition, there were many differences in the level of respiratory care according to the type of hospital. To overcome the current problems revealed, an effective in-hospital training program for the development of full-time respiratory care therapists should be established urgently in Korea.

• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.380-387
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• 2015

The anti-amnesic effect of Artemisia argyi H against trimethyltin (TMT)-induced learning and memory impairment and its neuroprotective effect against $H_2O_2$-inducedoxidative stress were investigated. Cognitive behavior was examined by Y-maze and passive avoidance test for 4 weeks, which showed improved cognitive functions in mice treated with the extract. In vitro neuroprotective effects against $H_2O_2$-induced oxidative stress were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromide and lactate dehydrogenase (LDH) assays. A. argyi H. extract showed protective effects against $H_2O_2$-induced neurotoxicity; moreover, LDH release into the medium was inhibited. Finally, high-performance liquid chromatography (HPLC) analysis showed that eupatilin and jaceosidin were the major phenolic compounds in A. argyi H. extract. These results suggest that A. argyi H. could be a good source of functional substances to prevent neurodegenerative diseases.

• Geophysics and Geophysical Exploration
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• v.26 no.2
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• pp.52-61
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• 2023

The use of ultra-high-resolution (UHR) seismic surveys to preceisly characterize coastal and shallow structures have increased recently. UHR surveys derive a spatial resolution of 3.125 m using a high-frequency source (80 Hz to 1 kHz). A digital streamer system is an essential module for acquiring high-quality UHR seismic data. Localization studies have focused on reducing purchase costs and decreasing maintenance periods. Basic performance verification and application tests of the developed streamer have been successfully carried out; however, a comparative analysis with the existing benchmark model was not conducted. In this study, we characterized data obtained by using a developed streamer and a benchmark model simultaneously. Tamhae 2 and auxiliary equipment of the Korea Institute of Geoscience and Mineral Resources were used to acquire 2D seismic data, which were analyzed from different perspectives. The data obtained using the developed streamer differed in sensitivity from that obtained using benchmark model by frequency band.However, both type of data had a very high level of similarity in the range corresponding to the central frequency band of the seismic source. However, in the low frequency band below 60 Hz, data obtained using the developed streamer showed a lower signal-to-noise ratio than that obtained using the benchmark model.This lower ratio can hinder the quality in data acquisition using low-frequency sound sources such as cluster air guns. Three causes for this difference were, and streamers developed in future will attempt to reflect on these improvements.

• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.143-152
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• 1988

This study was conducted to obtain basic data which affected engine performance of the power tiller being widely used in the rural area. Among the various factors affected engine performance, only flywheel weight was considered as the major factor in this study. Fuel consumption ratio, motoring loss, torque, vibration and mechanical efficiency of the engine tested were measured and analyzed on the four levels of flywheel weight (32.2, 29.7, 26.4, 24.2 kg). The results obtained were as follows: 1. The maximum output of 6 and 7.5 kW engine was 7.43 kW and 7.85 kW respectively. When flywheel weight was reduced from 32.2 kg to 24.2 kg, output power of the engine was increased 0.27 kW in 6 kW engine and increased 0.39 kW in 7.5 kW engine. 2. The fuel consumption ratio was decreased from 300.8 to 296.8 g/kW-hr in 6 kW engine and decreased from 313.6 to 312.8 g/kW-hr in 7.5 kW engine when the flywheel weight was reduced from 32.2 kg to 24.2 kg. 3. The mechanical efficiencies of the engine was increased from 76.1 to 76.8% in 6 kW engine and increased from 76.7 to 77.0% in 7.5 kW engine when the flywheel weight was reduced from 32.2 kg to 24.2 kg. 4. When the flywheel weight was reduced from 32.2 kg to 24.2 kg, a tendency of a little decrease of vibration at X- and Z-axis in 6 kW engine and of a little increase of vibration at Y-axis in 6 kW engine and all directions in 7.5 kW engine was observed. 5. Motoring losses was decreased from 2.33 to l.76 kW in 6 kW engine and decreased from 2.46 to 1.84 kW in 7.5 kW engine when the flywheel weight was reduced from 32.2 kg to 24.2 kg. From the above results and the flywheel weight calculated theoretically, it was recommendable that the flywheel weight should be reduced about 7 kg in 6 kW engine and about 10 kg in 7.5 kW engine, respectively.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.937-946
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• 2005

This experiment was conducted to investigate the effects of dietary Bacillus subtilis on growth performance, nutrient digestibility, immunological cells change, fecal noxious gas and carcass meat quality characteristics in finishing pigs. The dietary treatments were 1) CON(basal diet), 2) BS0.1(basal diet+ 0.1% Bacillus subtilis) and 3)BS0.2(basal diet+0.2% Bacillus subtilis). Sixty crossbred(Landrace$\time$ Yorkshire$\time$Duroc) pigs(89.5$\pm$0.11kg average initial body weight) were used in a 42 days growth trial. The pigs were assigned to the treatments according to body weight and each treatment had 5 replicates of 4 pigs per pen in a randomized complete block design. Through the entire experimental period, average daily gain(ADG) and average daily feed intake(ADFI) were not significantly different among the treatments. Pigs fed BS0.1 diet significantly increased their gain/feed compared to pigs fed CON and BS0.2 diets(P<0.05). Also, dry matter(DM) and nitrogen(N) digestibilities were greater in the pigs fed BS0.1 diet than those fed CON diet(P<0.05). There were no significant differences in fecal NH3-N concentration among the treatments. In blood assay for immunological cells change investigations, red blood cells(RBC) counts increased in the pigs fed BS0.2 diet compared to pigs fed CON and BS0.1 diets. There were no significant differences in carcass pH, drip loss, marbling and firmness. However, sensual color and a*(redness) value of meat in the pigs fed BS0.2 diet were higher than in pigs fed CON diet(P<0.05). Therefore, this experiment suggested that Bacillus subtilis supplementation could improve nutrient digestibility, RBC counts and carcass meat color of pigs.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.147-159
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• 1995

This study was conducted to introduce fundamental data of hand-arm vibration and noise exposure levels with impact wrenches(double-hammer impact wrenches and oil-pulse impact wrenches) used in automobile assembly lines considering the process variables and tool variables. In studing, products per day, required time screwing the bolts or nuts per bolts or nut were considered as process variables, and capacity of bolts or nuts, air consumptions per minute, tool weights, RPM were considered as tool variables. Hand-arm vibration levels of 3 axis in each hand were measured using the instruments compling with ISO/DIS 5349 and noise levels were measured using a noise logging dosimeter. The results were as follows : 1. Required time to screwing the bolt or nut by oil-pulse impact wrenches is shorter than double-hammer impact wrenches but total daily exposure time of oil-pulse impact wrenches was higher than double-hammer impact wrenches because the number of bolts or nuts per cycle was many. 2. Oil-pulse impact wrenches have been used to screwing the large bolt or nut in comparing with double-hammer impact wrenches and required time to screwing the bolts or nuts were shorter than double-hammer impact wrenches because oil-pulse impact wrenches were using high RPM and large air consumption per minute. Noise level of oil-pulse impact wrenches was 8 dB(A) lower than double-hammer impact wrenches. 3. Dominant hand-arm vibration levels of double-hammer impact wrenches in each hand were $8.24m/sec^2$ of Zh axis in right hand and $9.60m/sec^2$ of Xh axis in left hand. Dominant hand-arm vibration level of oil-pulse impact wrenches in each hand was $2.59m/sec^2$ of Xh axis in right hand and $3.23m/sec^2$ of Yh axis in left hand. 4. In double-hammer impact wrenches, corresponding hand-arm vibration levels of Xh, Yh, Zh axis in left hand were higher than hand-arm vibration levels of right hand in 3 axis. In oil-pulse impact wrenches, Xh axis of right, Yh axis of left, Zh axis of left were higher than the corresponding hand-arm vibration levels of Xh, Yh, Zh axis in right and left hand. 5. Correlation coefficients among Xh, Yh. Zh axis of right and left hand hand-arm vibration levels in double-hammer impact wrenches and oil-pulse impact wrenches were commonly high in Yh axis and correlation coefficients of Yh axis in double-hammer impact wrenches and oil-pulse impact wrenches were 0.76 and 0.86,respectively. 6. As a measure repetitiveness, plotting total daily exposure time with the number of bolts or nut per cycle, direct correlation was shown between repetitiveness and hand-arn vibration exposure, and correlation coefficient between the number of bolts or nut per cycle and total daily exposure time in double-hammer impact wrenches, oil-pulse impact wrenches were 0.84 and 0.50, respectively. 7. Considering the total acceleration level and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption in right hand, and bolt or nut capacity in left hand were commonly the variable that explainability was high. Considering the noise and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption per minute was commonly the variable that explainability was high.