• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.172-177
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• 2004

A planetary gear trains has characteristics in compactness, power transformation ability and constant meshing. Usability is increased in applications of auto transmission and industrial gearbox. Study on optimum design of planetary gear train has been progressed on minimization of weight, miniaturization of planetary gear train and improvement of high strength. There are demands of study for the planetary gear train required long lift estimation In this wort being considered life, strength, intereference, contact ratio and aspect ratio, the optimum design algorithm is proposed to reduce the volume of planetary gear train with transferring the same amount of power. In the design of algorithm for planetary gear train, the determination of teeth number is separated to achieve simplicity and the simulated annealing method as a global optimal technique is used for optimal design method.

• Journal of Korean Society for Quality Management
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• v.28 no.3
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• pp.145-154
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• 2000

Effective management of knowledge is essential to keep up with demands of this challenging information age. The first step for this kind of management would be to define indicators to evaluate the quality of knowledge. In this paper, we use five latent variables (intrinsic quality, representational quality, ease of use of quality, maintainable quality, usage of quality) as basis for a preliminary path analysis for knowledge management. Preliminary study results showed that high intrinsic quality does not necessarily guarantee high frequency of use. A modified questionnaire is made and is used for SERVQUAL. The result of SERVQUAL shows that customers are not relatively happy about both intrinsic quality and its ease of use. Additional path analyses are done for both expected and observed quality indicators. The path model based on the expectation indicated that the presentation method of knowledge would induce its easy maintenance while that based on observation did not back up the same phenomenon.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.175-183
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• 2005

In recent years, as the demands of VBNS and VDSL increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM elements increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this Paper, the optical alignment characteristic of multi-axis ultra precision stage is studied. The alignment algorithms are studied for applying to the ultra precision multi-axis stage. The alignment algorithm is comprised of field search and peak search algorithms. The contour of optical power signals can be obtained by field search and the precise coordinate can be found out by peak search. Three kinds of alignments, such as 1 ch. input vs. 1 ch. output optical stack, 1 ch. input vs. 8 ch. output PLC stacks, and ferrule vs. ferrule, are performed for investigating the alignment characteristics.

• Journal of Ocean Engineering and Technology
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• v.25 no.4
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• pp.48-53
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• 2011

Current trends in propeller design have led to the need for extremely complex blade shapes, which place great demands on the accuracy of design and analysis methods. This paper presents a new proposal for improving the prediction of propeller performance with a vortex lattice method using the lifting surface theory. The paper presents a review of the theory and a description of the numerical methods employed. For 8 different propellers, the open water characteristics are calculated and compared with experimental data. The results are in good agreement in the region of a high advanced velocity, but there are differences in the other case. We have corrected the parameters for the trailing wake modeling in this paper, and repeated the calculation. The new calculation results are more in agreement with the experimental data.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.6-8
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• 2004

Recently, the PM type stepping motor preferred solution for many small electronics position determination devices since it is small in size. Thus, there are glowing demands for permanent magnet(PM) type stepping motor that greater mechanical output, smaller size. This paper deals with a study of the miniaturization of the PM type stepping motor with claw-poles. We introduced the small-sized PM type stopping motor that has new structure and analyzed the magnetic characteristic of it versus general type model using 3-D finite element analysis(FEA).

• Journal of environmental and Sanitary engineering
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• v.18 no.3 s.49
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• pp.11-20
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• 2003

There are two ways of reducing air pollution. One is the approach of the pollutant source control and the other one is the traffic demand decreasing approach. This study is focusing on the approach of land use planning and optimal location of urban facilities because those are the basic cause to generate transportation demands. So, the purpose of this study would be to analyze the changes of NOx and CO distribution on environmental air by functional hierarchy of urban roads and to make evaluation model of 'Transportation-Land Use -Air Pollution'. It will contribute to improve the air pollution level at same actual traffic generation according to different location.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.782-787
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• 2002

In optical disk drives (ODD), the demands of high data density and high speed have been increasing rapidly to achieve high data capacity and data transfer rate. The short wavelength laser, High NA objective lens, and high track following performance are needed to raise data density and data rate. For high-performance actuator, the improvement of linearity and acceleration become more important. Also, 3-axis actuator for active tilt compensation is introduced to overcome the decrease in disk tilt tolerance which is induced by short wavelength laser. In this paper, a hybrid type 3-axis actuator is presented and a new yoke structure, which can reduce the interaction between yoke and moving magnet, is designed to keep the efficiency of magnetic circuit. Experimental results show the validity of the yoke in the hybrid type actuator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.375-380
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• 2002

As the data storage device market demands higher data transfer rate with higher track density. TMR budget is to be tighter so that even minor improvement is sought in HDD development fields. Disk flutter associated with the turbulent air flow inside the chamber becomes of great interest for the reduction of PES especially at OD. A comparative transient turbulent flow study is presented in this paper for the reduction of disk flutter with different housing designs.

• Korean Journal of Organic Agriculture
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• v.12 no.3
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• pp.249-264
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• 2004

High yield arable and crop farming demands a temporally and quantitatively determined application of plant nutrients according to field and culture. The nutrients may come from commercial fertilizers or from animal wastes. Regarding the dangers to soil, water and air, which come from current agricultural application measures for nitrogen, a sectoral approach for a nonpolluting liquid manure utilization can-not be used ally longer. An integrated system approach has to be found, leading to a drastic improvement of nutrient utilization and hence to a considerably reduced nutrient use. This can be only expected, if the organic manure can be applicated at times, when losses through leaching and volatilization can be minimized.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.111-116
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• 2011

Incheon International Airport is becoming a hub in the Northeast Asia region since its opening in 2001. Along with an increasing volume of air traffic, demands for airspace are also increasing significantly. In particular, air traffic delays have been growing rapidly due to an increasing volume of air traffic, specially flying to Europe through China. And therefore, there should be an alternative protocol to prevent flight delays. The main purpose of this study is to review current West Sea Airways of G597/Y64 which contains highly potential problems and to evaluate the efficacy of double-tracked airways in the west sea area.