• Journal of Korean Society of Transportation
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• v.21 no.6
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• pp.57-65
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• 2003

Traffic congestion on the streets is the major concern of Metropolitan areas in Korea. Especially the signalized intersections are the main spots where traffic congestion is to be created. Currently the subway construction has been on the process in Taegu Metropolitan city. The subway stations are usually located at the intersections where a large number of vehicles and people are moving. During the constructional period, such an intersection creates profoundly a great deal of traffic congestion due to the open-cut constructional method. Under circumstance of the constructional method, the lane configurations should be changed frequently and the surface conditions make drivers uncomfortable. The propose of this study is to propose the improved method of traffic operation at the large circled intersection under the construction. The Signalized Modern Roundabout(SMR) is applied modifying from the modern roundabout. The geometric design and signal operation of SMR is developed in this study. To verify the operation of SMR the comparative study is conducted between the operation of the open-cut method and SMR method using the micro-simulation program, NETSIM. The result of simulation shows that the delay caused by the operation of SMR is not higher than that under the open-cut method. SMR makes also the constructional period shorten, makes the cost of construction lessened and makes drivers more comfortable as well than the method of open-cut. Therefore, the study concludes that the operation of SMR is more efficient, economic and safer method than that of open-cut method at the large circled intersection under construction.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.313-320
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• 2009

This experiment was conducted to evaluate the effect of tillage system and fertilizer type on the forage yield and quality of Italian ryegrass. This experiment was a $2{\times}2$ factorial arrangement for two tillage systems (tillage and no-tillage) and two fertilizer type (chemical and manure compost). The plant height, dry matter (DM) content, DM yield, TDN (total digestible nutrients) yield, and CP (crude protein) yield have significant differences in tillage system of Italian ryegrass. Italian ryegrass cultivated with tillage (plow and rotary till) had lower plant height, DM yield, TDN yield and CP yield than no-tillage, while its DM content showed the opposite results. However, there were no significant differences in the results on fertilizer types. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents were significantly higher in no-tillage compared to tillage. However, there was no significant difference in CP content on tillage system. TDN and relative feed value (RFV) were higher in tillage than no-tillage system (p<0.01). The TDN content was lower when using manure as fertilizer. No significant effects were observed for NDF and RFV in fertilizer type of Italian ryegrass. Based on the results of this study, tillage system and fertilizer type affected forage quality as well as forage yield. Forage yield of no-tillage was higher compared to tillage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.4
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• pp.361-366
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• 2017

This study was conducted to evaluate effects of seeding rate and depth during broadcast sowing on growth and yield of foxtail millet and proso millet over 2 years. The rate of sowing seeds was adjusted to 5, 7, 10 and 20 kg per ha on foxtail millet, and 5, 10, 15 and 30 kg per ha for proso millet. Sowing depth was 0.5, 1, 3, 5, 7, and 10 cm used tractor rotary attachment for shallow-tilling. The rate of seedlings standing when foxtail millet and proso millet were sowed to a depth of 0.5~5 cm was 72.0~78.0% and 73.0~80.5%, respectively. Plant height and weight at the three-leaf stage after emergence was highest for the treatment with 3 cm rotary depth. As the rate of broadcast seed sowing increased, plant length, diameter, seed length, and seeds on the panicle decreased. The grain yield of foxtail millet was highest with broadcast seed sowing of 10 kg per ha (3652, $3977kg\;ha^{-1}$) and proso millet was highest at broadcast seed sowing of 15 kg per ha (2226, $2052kg\;ha^{-1}$) in 2012 and 2013, respectively. Therefore, the optimum rate of sowed seeds under broadcast cultivation was $10kg\;ha^{-1}$ for foxtail millet and $15kg\;per\;ha^{-1}$ for proso millet. Optimum sowing depth for foxtail and proso millet under broadcast cultivation was 3 cm, using a rotary tractor attachment for shallow-tilling.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.1
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• pp.25-33
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• 2021

With the development of machine learning techniques, various types of data such as vibration, temperature, and flow rate can be used to detect and diagnose abnormalities in machine conditions. In particular, in the field of the state monitoring of rotating machines, the fault diagnosis of machines using vibration data has long been carried out, and the methods are also very diverse. In this study, an experiment was conducted to collect vibration data from normal and abnormal compressors by installing accelerometers directly on rotary compressors used in household air conditioners. Data segmentation was performed to solve the data shortage problem, and the main features for the fault classification model were extracted through the chi-square test after statistical and physical features were extracted from the vibration data in the time domain. The support vector machine (SVM) model was developed to classify the normal or abnormal conditions of compressors and improve the classification accuracy through the hyperparameter optimization of the SVM.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.105-110
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• 2012

This study deals with the accident models of rotary. The objectives is to develop the models by day and nighttime. In pursuing the above, this study gives particular attentions to collecting the data of geometric structure and accidents of 20 rotaries and developing the Poisson and negative binomial regression models using NLOGIT 4.0. The main results are as follows. First, the numbers of accident of nighttime (1.03 per 1,000 entering vehicles) were analyzed to be very higher than those of day (0.47 per 1,000 entering vehicles). Second, 4 Poisson models which were all statistically significant were developed, in which the dependent variable were both the number of accident and EPDO (equivalent property damage only). Finally, the number of entry/exit ($X_1$) and the number of entering lane ($X_5$) in the models of the number of accident, and $X_1$ in the EPDO models were adopted as the common variables. The variables were analyzed to be all positive to the dependent variables.

• Journal of Drive and Control
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• v.13 no.4
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• pp.1-6
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• 2016

Typically, the seat of an automotive vehicle generally includes a horizontal seat-cushion portion and a vertical seat-back portion that is operatively connected to the seat-cushion portion. The seat may include a recliner for the reclining of the seat-back portion relative to the seat-cushion portion by the seat occupant. An energy absorber or damper can also be provided for the seat-back portion. Because the recliner is configured to be released at a relatively high speed, and it results in an impact at the end of a folding stroke, the damper needs to dissipate energy as the seat back moves with respect to the seat cushion; therefore, the role of the seat damper in the automotive-seat design is important. In this paper, the mechanism of an hydraulic-type automotive-seat damper is investigated, and the torque characteristic is simulated according to the design-parameter variations such as the orifice area and the working-fluid properties.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.221-226
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• 2002

One of the serious challenges in developing rotary compressor with HFC refrigerant is the prediction of scuffing times and wear amounts between vane and roller surfaces. In this study, the tribological characteristics of sliding surfaces using vane-roller geometry of rotary compressor were investigated. The sliding tests were carried out under various sliding speeds, normal loads and surface roughness. During the test friction force, wear depth, time to failure and surface temperature were monitored. Because severe wear was occurred on vane surface, TiN coating was applied on sliding surfaces to prolong the wear-life of vane-roller interfaces. From the sliding test it was found that there was the optimum initial surface roughness to break in and to prolong the wear life of sliding surfaces. Depending on the load and speed, the protective layers, which were composed of metallic oxide and organic compound, were formed on sliding surfaces. Those would play an important role in role amounts of friction and wear between miler and vane surfaces.

• Journal of Biosystems Engineering
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• v.15 no.3
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• pp.177-185
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• 1990

The break of rotary blade is occured from a stress concentration of the inside of blade by the outside impulsive load. In order to examine its inside stress and stress concentration of rotary blade, a epoxy plate which is suitable to applicate by photoelastic system is used to experiment. These results are summarized as follow. 1. Refer to the existence of bolt hole and a size of its of rotary blade, a stress concentration which cause the break of rotary blade is not exposed. 2. It is expected to be break to section of hold of rotary blade and the break of this is due to that there are concentrated by shearing force, bending moment and bending stress. 3. When the crack which caused from processing are set up to any location, the stress concentration taken to the creak point. 4. Without regard to the location of the reaction points of rotary blade, the bending stress which is greated than the bending moment is occured within about 6 em toward the center line of bolt hole and it was possible to break that section.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.108-113
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• 2005

In this study, rotary type diamond dressing system for ultra-precision centerless grinding for ferrule was developed at the first time and experiments were conducted with AE sensor and hall sensor system to verify the optimum dressing condition for ultra-precision centerless grinding for ferrule. The correlations with the condition of dressing are evaluated by AE signal analysis with root mean square (RMS) and frequency analysis. And current signals from hall sensor are also studied as a factor of dressing optimum condition selection. Dressing process was conducted to investigate the effects of depth of cut, rotating speed, and the number of overlap to select the optimum condition of rotary dressing system of ultra-precision centerless grinding machine for ferrule fabrication. In order to verify the optimum condition of dressing, AE and current signals were compared with the surface quality of dressing wheel and grinding wheel for ultra-precision ferrule grinding. All of these experiments were completed by Taguchi Methodology to reduce experimental time. Hence, the optimum condition of rotary dressing system for ultra-precision centerless grinding for ferrule fabrication can be selected following to the experiment result from signals of AE and hall sensor.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.43-50
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• 2002

In the design of structure, the forces acting on tai structure are key parameter fur noise and vibration control. However, in the complex structure, the forces at the injection point on the structure cannot be measured directly. So, it is necessary to find out Indirect force evaluation method. In this paper, forces have been measured with In-situ vibration responses and system information. And, three existing techniques of indirect force measurement, vita. direct inverse. principal component analysis and regularization have been compared. This paper shows that multi-vibration responses are essential for talc precise estimation of the forces. To check these conditions, rotary compressor is adopted as test sample, because it is very difficult to measure the injection forces from internal excitation to shell. It alas also been obtained that relatively higher force is transmitted through three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation with curvature shell and plate.