• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.2
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• pp.61-70
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• 1984

This paper examines the array antenna theory, basic relations between the array size (aperture) and its beamwidth and resultant patterns. This paper also provides array antenna system design criteria, mainly maximizing the signal-to-noise ratio (SNR) and its corresponding optimum array structure and weight functions. Explicit new expressions for array performance are also illustrated in terms of the array output SNR. An example is provided for a 37-element planar array to explicitly illustrate the beam-forming and nulling operations of the array. Fundamentals of sidelobe canceller (SLC) systems have been discussed along with a derivation of new SLC equations for optimum weights.

• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1171-1180
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• 2018

Korea's water transmission system is operated by the nonpressure flow method that flows from highlands to lowlands due to the nature of Korea with many mountainous areas. In order to store water in the highlands, the water pumps are installed and operated. However, In this process, a lot of electrical energy is consumed. therefore, it is necessary to minimize the energy consumption by optimizing the size and operation schedule of the water pumps. The optimal capacity and operation method of the water pump are affected by the size of the tank (distributing reservoir). Therefore, in order to economically design and operate the water transmission system, it is reasonable to consider both the construction cost of the water pump and the tank and the long-term operation cost of the water pump at the step of determining the scale of the initial facilities. In this study, the optimum design model was developed that can optimize both the optimal size of the water pump and the tank and the operation scheduling of the water pump by using the genetic algorithm (GA). The developed model was verified by applying it to the water transmission systems operated in Korea. It is expected that this study will help to estimate the optimal size of the water pump and the tank in the initial design of the water transmission system.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.25-31
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• 2007

The recent frequent heavy rainfall has caused an increased in soil erosion and the soil drain which drained soil has caused decreased in channel radius and environmental problems by turbidity. In this study, the optimum size of the sediment basin was tested with soil erosion estimated from the Universal Soil Loss Equation (USLE) in the basin using by GIS data. The results show that the estimated soil erosion and the designed soil deposit are $72.1\;m^3$ and $85.0\;m^3$ respectively and the size of sediment basin is proper. In this study the water depth was calculated from the Hec-Ras model to test the stability of the bank and to prove submersion of the inside fields from stream overflow.

• Resources Recycling
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• v.28 no.2
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• pp.23-30
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• 2019

An color sorting technique was introduced to recycle End-of-life automobile shredded bumpers. The color sorting is a innovate method of separating the differences in the color of materials which are difficult to separate in gravity and size classification by using a camera and an image process technique. Experiments were planned and optimal conditions were derived by applying BBD (Box-Behnken Design) in the reaction surface method. The effects of color sensitivity, feed rate and sample size were analyzed, and a second-order reaction model was obtained based on the analysis of regression and statistical methods and $R^2$ and p-value were 99.56% and < 0.001. Optimum recovery was 94.1% under the conditions of color sensitivity, feed rate and particle size of 32%, 200 kg/h, and 33 mm respectively. The recovery of actual experiment was 93.8%. The experimental data agreed well with the predicted value and confirmed that the model was appropriate.

• New & Renewable Energy
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• v.7 no.3
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• pp.92-100
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• 2011

With the increased demand of clean energy and global warming measures, the renewable energy development has been increased recently. The TCP (Tidal Current Power) is one of the ocean renewable energy sources. Having the high tidal energy source in Korea, there are many potential TCP sites with strong current speed. The rotor, which initially converts the energy, is a very important component because it affects the efficiency of the entire system. The rotor performance is determined by various design parameters including number of blades, shape, sectional size, diameters and etc. However, the interactions between devices also contribute significantly to the energy production. The rotor performance considering the interaction needs to be investigated to predict the exact power in the farm. This paper introduces the optimum design of TCP turbine and the performance of devices considering the interference between rotors.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.151-156
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• 2000

Ultra precision progressive die have used for above one million's lot size of production part. In the field of design and making tool for press working, the progressive die for sheet metal (STS 304, thickness : 0.5mm) is a specific division. In order to prevent the defects, the optimum design of the production part, strip layout, die design, die making and tryout etc. are necessary. They require analysis of many kinds of important factors, i.e. theory and practice of metal press working and its phenomena, die structure, machining condition for die making, die materials, heat treatment of die component, know-how and so on. In this study, we designed and constructed a progressive die of multi-stage and performed try out. Out of these processes the die development could be taken for advance. Especially the result of tryout and its analysis become the characteristics of this paper (part 1 and part 2) that nothing might be ever seen before such as this type of research method on all the processes. In the part 2 of this study we treated die making and tryout mostly.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1232-1240
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• 2002

Recently, linear motors are applied to many small precision products. Thus high generating power with small size is required of it. In order to increase the motor efficiency, the design variables need to be optimized. In this study, Vector Fields FEM software, OPERA-3d, was used for simulating linear motor. The thrust and magnetic flux density at the air-gap center were simulated and compared with the experimental results. Taguchi method was applied to investigate the effects of each variables. As a result, the thickness of conductor and magnet was important for the thrust but the thickness of the yoke. The temperature of the conductor was determined by finding the thermal conductivity that was determined by experimentation. Correlation equation relating to the thrust and temperature was proposed by Latin square and Least Square method. The optimum design variables were determined by correlation equation, and compared with simulation results. According to this analysis, thrust force of linear motor was improved about 7% comparing with conventional model.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.231-235
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• 2000

Precision progressive die have used for above ten thousand pieces of lot size production part. In the field of design and making tool for press working, the progressive die for sheet metal (SPC, thickness : 2mm) is a specific division. In order to prevent the defects, the optimum design of the U-bending production part, strip layout, die design, die making and tryout etc. are necessary. They require analysis of many kinds of important factors, i.e. theory and practice of metal pres working and its phenomena, die structure, machining condition for die making, die materials, heat treatment of die component, know-how and so on. In this study, we designed and constructed a progressive die of multi-stage and performed try out. Out of these processes the die development could be taken for advance. Especially the result of tryout and its analysis become the characteristics of this paper (part 1 and part 2) that nothing might be ever seen before such as this type of research method on all the processes. In the part 2 of this study we treated die making and tryout mostly.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.218-223
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• 2000

Ultra precision progressive die have used for above one million's lot size of production part. In the field of design and making tool for press working, the progressive die for sheet metal (STS 304, thickness : 0.5mm) is a specific division. In order to prevent the defects, the optimum design of the production part, strip layout, die design, die making and tryout etc. are necessary. They require analysis of many kinds of important factors, i.e. theory and practice of metal press working and its phenomena, die structure, machining condition for die making, die materials, heat treatment of die component, know-how and so on. In this study, we designed and constructed a progressive die of multi-stage and performed try out. Out of these processes the die development could be taken for advance. Especially the result of tryout and its analysis become the characteristics of this paper (part 1 and part 2) that nothing might be ever seen before such as this type of research method on all the processes. In the part 2 of this study we treated die making and tryout mostly.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.735-741
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• 2003

A simplified view of array design and application process was introduced. Array design is critical to achieve a successful phased array measurements. A planar microphone array is designed to produce optimum performance and also to fit economic requirement in integrating data acquisition system. Certain performance characteristics are of primary concern when designing arrays. These characteristics include array resolution, spatial aliasing and array sidelobe suppression. Every array has its directional pattern that shows such characteristics. Assuming that a monopole source is located in center, beam-patterns have been simulated varying measurement conditions such as number of sensors. array aperture size, distance between array and source, frequency of interest and so on. Sensor correction was conducted on very channel using magnitudes and phased of FRF with respect to a reference microphone channel. Then with a spiral type array, measurements have been made with two point sources of same frequency in order to investigate array resolving abilities. It is observed that higher frequency source achieves better resolution than lower one does.