• Journal of Institute of Control, Robotics and Systems
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• v.9 no.8
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• pp.632-639
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• 2003

This paper proposes a simple compensation scheme for the time delay caused by measurement, calculation and selection of voltage vector in Direct Torque Control (DTC) of an induction motor. In general scheme, it is difficult to know the exact delay time, furthermore the delay time can be varied by program routines for calculation and processing of measured data. In this proposed scheme, by applying voltage vector at the beginning of next sampling period, a fixed delay time is achieved and its compensation becomes much simpler. Furthermore, with the simple compensation algorithm, an improved performance can be achieved by shortening sampling period. Experimental results prove the feasibility of the proposed scheme in induction motor control.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.174-181
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• 2004

Recently, many studies have been undergoing to reduce working time in field of machine tool. There are two ways of reducing working time to reduce actual working time by heighten spindle speed and to reduce stand-by time by shortening tool exchange time. Auto tool changer belongs to latter case. Fixed address type auto tool changer can store more number of tools in small space than magazine transfer Ope and can shorten tool exchange time. This study focuses on the topology optimization to reduce the weight of the fixed address type ATC. The optimization program using a real number coding genetic algorithm is developed and is applied to the 10-bar truss optimization problem to verify the developed program. And, it is shown that the developed program gives better results than other methods. Finally, The developed program applied to optimize the fixed address type ATC.

• Journal of Korea Multimedia Society
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• v.22 no.2
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• pp.281-291
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• 2019

In order to reflect complex and diverse building types, resident characteristics and disaster factors, it is necessary to introduce a flexible situation-based response system based on real-time information. Intelligent CCTV, hybrid sensor, location scanner, and customized broadcasting device were examined to introduce for the real-time response intelligent response system and its feasibility was verified through field test. In addition, based on the real-time information, the evacuation simulation was executed by assuming the dormitory building and the resident of the school, and the safety of the evacuation and the shortening of the pinnacle time were confirmed. The feasibility of real time information based evacuation comparing with the existing evacuation system were verified in the case of evacuation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1505-1510
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• 2018

Product modeling technology for graphics is rapidly developing. And 3D data application and usability are increasing.modeling of product design is a very important factor in constructing. 3D modeling in product design takes a lot of production time. Recently, the reverse design method is very useful because of application of 3D data and shortening of production time. In this study, first, 3D point cloud and mesh data are generated using photographs based on image data. The second is to modify the design and the third is to make the prototype with the 3D printer. This product design and production process suggests the utilization and possibility of image data, the shortening of 3D modeling production time and efficient processes. Also, the product design process proposes a model of a new product development system to adapt to the production environment.

• Land and Housing Review
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• v.3 no.4
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• pp.415-421
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• 2012

In case of Korean housing complex, there became more mixed arrangement of buildings with different number of layers for a variety of urban skyline, recently. For example, around 33% of the construction sites of 'A' public corporation have gaps of more than 4 layers between high-rise buildings and low-rise ones in the same site, according to the survey. Generally, construction duration of the housing complex is estimated based on the layers of the highest building. Due to this baseline, whole construction duration could be extended so that the project cost could be increased. Therefore, framework duration of higher-rise buildings should be reduced to secure the feasibility of the project. On the other hands, these shortenings could adversely harm the feasibility in some cases because there are a wide range of combinations of the buildings with different number of layers in designing housing complex. Therefore, this study shows the results of analysis on effects of framework time shortening on the cost in housing complex project. Moreover, this could set the baseline of checking possibilities in condensing the construction duration of projects with buildings of different layers by supplying comprehensive database.

• Design & Manufacturing
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• v.8 no.1
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• pp.31-34
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• 2014

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. It spends most of times in the cooling process. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating. However, if response time of temperature controller and sensor will be increased, the performance of this system will increase.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.38-42
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• 2009

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. now then, cooling process spends the most of times in Injection molding cycle time. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.111-114
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• 2008

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. It spends most of times in the cooling process. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating. However, if response time of temperature controller and sensor will be increased, the performance of this system will increase.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.3
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• pp.32-38
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• 2001

Multi-carrier data transmission system performance is mostly limited by Inter- symbol-interference that is caused by a dispersive characteristic of the transmission channel. In order to enhance the system performance to meet the service requirements of local access, the channel impulse response shortening method incorporated with a channel frequency response compensation method is proposed. For a fast and efficient implementation of the equalizer proposed, Kalman and LMS algorithms are successively used. To verify the channel equalization performance, a set of computer simulation is performed on a filter bank based multitone system operating in a typical high-speed local area data transmission environment. The results showed us a comparable signal-to-interference improvement over the conventional multitone equalization scheme.

• Journal of Navigation and Port Research
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• v.41 no.2
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• pp.39-46
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• 2017

This study represents a fundamental research for a passenger-ship escape guidance system that is a ship-borne agent, and it is for the support of escape decision-making by providing accurate maritime safety information in real time. We conducted a passenger escaping experiment on a training ship, SAEYUDAL, using the situation-aware escape guidance system, which has been developed for on-board application based on products for buildings. It is shown that the system contributes to the shortening of the escape duration and the dispersion of the escaping persons by generating and guiding the safe escape routes which dangerous areas are considered. From the experiment on ship's heeling condition, it is revealed that the heeling angle is linearly related to the escape duration. Therefore, this study shows that the shortening of the escape duration enables a safe and rapid mustering that is the most important process under emergency and appropriate incident responses to minimize loss of lives.