• Korean Journal of Computational Design and Engineering
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• v.12 no.1
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• pp.39-49
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• 2007

Recently three-dimensional (3-D) die design and production process has been widely introduced into the tooling shops of automotive manufacturers to reduce time-to-production of brand-new automobiles. 3-D solid models created in CAD systems are used not only for various simulations for design verification, but also for NC tool path generation to machine dies and their Styrofoam patterns. However, a lot of time and cost will be required to build solid models for dies if designers use only the generalized modeling capabilities of commercial 3-D CAD systems. To solve this problem, it is necessary to customize 3-D CAD system for the specific die design and manufacturing process. This paper describes a dedicated 3-D CAD system based on Unigraphics for die design for automotive body panels. The system provides not only 3-D design capabilities, but also standard part libraries, to enhance design productivity. The design process modeling technology has been introduced to facilitate redesign of the die for the modified panel. By introducing this system, dies can be designed more rapidly in the 3-D space, and their solid data can be directly transferred to CAM tools for NC tool path generation and simulation tools for virtual manufacturing.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.307-310
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• 2005

The Solar-B is the third Japanese spacecraft dedicated for solar physics to be launched in summer of 2006. The spacecraft carries a coordinated set of optical, EUV and X-ray instruments that will allow a systematic study of the interaction between the Sun's magnetic field and its high temperature, ionized atmosphere. The Solar Optical Telescope (SOT) consists of a 50cm aperture diffraction limited Gregorian telescope and a focal plane package, and provides quantitative measurements of full vector magnetic fields at the photosphere with spatial resolution of 0.2-0.3 arcsec in a condition free from terrestrial atmospheric seeing. The X-ray telescope (XRT) images the high temperature (0.5 to 10 MK) corona with improved spatial resolution of approximately 1 arcsec. The Extreme Ultraviolet Imaging Spectrometer (EIS) aims to determine velocity fields and other plasma parameters in the corona and the transition region. The Solar-B telescopes, as a whole, will enable us to explore the origins of the outer solar atmosphere, the corona, and the coupling between the fine magnetic structure at the photosphere and the dynamic processes occurring in the corona. The mission instruments (SOT/EIS/XRT) are joint effort of Japan (JAXA/NAO), the United States (NASA), and the United Kingdom (PPARC). An overview of the spacecraft and its mission instruments are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1424-1428
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• 2005

This paper describes a dedicated three-dimensional CAD system for design of drawing dies for automotive body panels. Since solid die models are useful not only for simulations for design verification, but also for NC tool path generation to machine dies and their Styrofoam patterns, 3-D CAD systems have been introduced in the tooling shop of automotive manufacturers. However, the work to build solid models requires a lot of time and effort if the designer uses only the general modeling capabilities of commercial 3-D CAD systems. To solve this problem, we customized a 3-D CAD system for the drawing die design. The system provides not only 3-D design capabilities, but also standard part libraries to enhance design productivity. By introducing this system, the drawing dies can be designed more rapidly in the 3-D space, and their solid data can be directly transferred to CAM tools for NC tool path generation and simulation tools for virtual manufacturing

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1031-1046
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• 2018

Vehicular ad hoc network (VANET) is a dedicated network to connect vehicles without any centralized administration or infrastructure. The wireless access in vehicular environments (WAVE) protocol leveraging IEEE 1609/802.11p is widely implemented for VANETs. However, in congested traffic situation, the performance of the WAVE system degrades significantly due to serious collision, especially for safety related broadcast services on the control channel (CCH) interval due to the inherent drawback of its collision avoidance mechanisms called carrier sense multiple access with collision avoidance (CSMA/CA). In this paper, we propose a method that can decrease the number of frame collisions in CCH with a few modifications to the IEEE 802.11p protocol. In the paper, vehicles still employ CSMA/CA to compete for the channel access opportunity. However, by taking advantage of periodicity of synchronization interval, a two-state switching scheme introducing two new inter frame space (IFS) is proposed to reduce the number of competing vehicles substantially and as a result, the collision probability is significantly decreased. The simulation results demonstrate the superiority of the proposed method in packet collision rate.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.401-407
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• 2009

The improvement in the terminal productivity plays a key role for container terminals to be more competitive. The productivity of yard tractors(YT) is one of the most important factor accelerating the terminal productivity. Thus, YT pooling system is newly introduced in container terminals for increasing the YT productivity. Recently, the terminals in Korea tend to adopt YT pooling system. This paper proposes the important decision factors for YT pooling work space and several types of formulations according to states of container terminals.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4549-4566
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• 2017

This work presents a novel facial descriptor, which is named as multiscale adaptive local directional texture pattern (MALDTP) and employed for expression recognition. We apply an adaptive threshold value to encode facial image in different scales, and concatenate a series of histograms based on the MALDTP to generate facial descriptor in term of Gabor filters. In addition, some dedicated experiments were conducted to evaluate the performance of the MALDTP method in a person-independent way. The experimental results demonstrate that our proposed method achieves higher recognition rate than local directional texture pattern (LDTP). Moreover, the MALDTP method has lower computational complexity, fewer storage space and higher classification accuracy than local Gabor binary pattern histogram sequence (LGBPHS) method. In a nutshell, the proposed MALDTP method can not only avoid choosing the threshold by experience but also contain much more structural and contrast information of facial image than LDTP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.44-46
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• 2018

In this paper, we design a system that can control unmanned mobile objects through communication between unmanned mobile object and control server system using LoRa network which is a dedicated IoT network. It is more efficient when the unmanned mobile object performs the special work by installing the LoRa network applied to the unmanned mobile object control system from the small space house or office hospital to the factory. In this paper, we will discuss the design of a system that can improve the social utilization of unmanned mobile objects by making it possible to communicate the events that occur around other mobile objects from the simplification of the navigation path.

• Journal of Information Display
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• v.3 no.3
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• pp.1-11
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• 2002

Multi-view function is important to three-dimensional displays without dedicated glasses. It is the reason that the observers earnestly desire to change their positions freely. Multi-viewing is also principal to the reality of three-dimensional (3D) image displayed on the screen. The display of projection type has the advantage that the number of viewing points can be easily increased according to the number of projectors. The authors research on multi-view projection display with hologram screen. Powerful directionality of the diffracted beam from hologram screen is required unlike two-dimensional (2D) display. We developed a new method that all diffracted beams satisfied the same Bragg condition and became sufficiently bright to observe the 3D image under usual indoor light. The principle is based on the essential Bragg diffraction in the three-dimensional space. Owing to such three-dimensional Bragg diffraction we achieved an excellent hologram screen that could be multiple reconstructed in spite of single recording. This hologram screen is able to answer arbitrary numbers of viewing points within wide viewing zone. The distortion of 3D image becomes also sufficiently small with the method of dividing the cross angle between illumination and diffraction beam.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.351-358
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• 2000

This study was conducted to develop a speed control system of a DC motor which drove a barley seeder mounted on a combine harvester. Barley seeder mounted on a combine has been known to reduce labor and cost of barley cultivation. However, development of the seeder has been unsuccessful because the combine, a dedicated rice and barley harvester has not enough space and proper power take-off for barley seeder. To develop a barley seeder, small powered motor speed controller was required. A proximity sensor for detecting working speed of the combine and a programmable one board microprocessor was used to develope a control system. Motor parameters and motor constant, relationship between seeding rate, motor speed, groove volumes of a tested roller, torque were measured. The proximity sensor sent a frequency signal to the microprocessor. In laboratory experiments, the excitation voltage of the motor was shown not to be proportional to the size of pulse width (duty ratio). A table transforming frequency signal, that represented for working speed to proper pulse width was developed from seeding rate experiments. However, seeding rate at low frequency signal was not proportional to the working speed. Seeding rate control proportional to the frequency signal was achieved by shifting of the frequency signal.

• Journal of Information Technology and Architecture
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• v.9 no.1
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• pp.67-78
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• 2012

Organizations have many physical servers in their departments such as application servers, web servers, database servers, mail servers, and so forth. The problem of server sprawl is common in information system centers of most profit and nonprofit organizations. Server sprawls are characterized by the use of dedicated servers for single applications. This server sprawl causes the problems such as the low resource utilization, the large space consumption, and the high management cost. Server consolidation is crucial to solve these problems by providing savings in hardware, software, maintenance, facility, and labor costs. This paper proposed a method to implement server consolidation for public organizations by the NDMS(National Disaster Management Systems) case study.