• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2092-2099
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• 2013

Through the data transfer race in industry since 1990s, the operational speed of optical disk drive(ODD) becomes commonly over 10,000 rpm. Such high speed operation inevitably causes the vibration, which is also the disturbances in the read-write process of pick-up servo-controller. Generally the vibration disturbance problem can be solved by the vibration isolation using the rubber mount and the increase of robustness of the pick-up servo-controller. Optical disk itself has not been targeted for the vibration reduction, because it is manufactured under the standardized format. In this paper we focused on the increase of critical speed of optical disk, that is, the improvement of dynamic characteristics, with the control of residual stresses which are come from the injection molding process. To do this, first, the residual stresses induced from the injection molding process are calculated using finite element method. The major design parameters of the process conditions are flow rate and melt temperature, which control the residual stresses in optical disk. Second, the critical speed of optical disk is calculated with modal analysis considering residual stress distributions. It was found out that the critical speed can be improved by the control of operational parameters in the injection molding process.

• Journal of the Korea Computer Industry Society
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• v.4 no.4
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• pp.547-552
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• 2003

In this thesis, interference phenomena of bluetooth networks requiring Security were minimized; strengthened security of piconet by assigning an identical PIN code to bluetooth devices, which was establishing a specific piconet during authentication stage. To establish a bluetooth piconet system. an unique ID was assigned to each bluetooth device, communication algorithms having different data formats between devices was designed, and an embedded hardware module using ARM processor and uCOS-II RTOS was implemented. About 30% of CPU efficiency in the module was increased by modifying functions including block parameters to work as nonblocking; by the increased efficiency of total piconet, the module could be used as an access point. The module could transmit maximum 10 frames of image and also audio signal by switching the packet effectively according to channel condition. By above-mentioned process, video, audio, and data could be well transmitted by the bluetooth managing program and the possibility of a commercial remote control system using bluetooth technology was suggested.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.2
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• pp.84-91
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• 2003

KOMPSAT series use software-controlled unregulated bus system in which the main bus is directly connected to a battery and the duty-ratio for PWM switch is controlled by the on-board satellite software. This paper proposes a new power-stage circuit that can be available for modularization of the power regulator which is used at the software-controlled unregulated bus system satellite. And we analyze the proposed power-stage operation according to its operating modes and verify it by performing software simulation and hardware experiment using prototype. We construct a parallel-module converter which is composed of proposed power-stages and perform experiment to verify modular characteristics of the proposed power-stage. Finally, we verify the usefulness of the proposed power-stage by comparing above results with those of a parallel-module converter made of conventional power-stages.

• Convergence Security Journal
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• v.24 no.1
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• pp.51-57
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• 2024

Although industrial control systems (ICSs) recently keep evolving with the introduction of Industrial IoT converging information technology (IT) and operational technology (OT), it also leads to a variety of threats and vulnerabilities, which was not experienced in the past ICS with no connection to the external network. Since various control command messages are sent to field devices of the ICS for the purpose of monitoring and controlling the operational processes, it is required to guarantee the message integrity as well as control center authentication. In case of the conventional message integrity codes and signature schemes based on symmetric keys and public keys, respectively, they are not suitable considering the asymmetry between the control center and field devices. Especially, compromised node attacks can be mounted against the symmetric-key-based schemes. In this paper, we propose message authentication scheme based on double hash chains constructed from cryptographic hash function without introducing other primitives, and then propose extension scheme using Merkle tree for multiple uses of the double hash chains. It is shown that the proposed scheme is much more efficient in computational complexity than other conventional schemes.

• Journal of Practical Engineering Education
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• v.11 no.2
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• pp.283-289
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• 2019

Recently, product mobility, data compatibility and communication connectivity have become very important to the control system, depending on the application of smart manufacturing. Accordingly, embedded systems are essential in all industries including home appliances, telecommunication, and national defense. Therefore, the demand for embedded system development personnel is increasing further, and education and training programs are needed to combine the practical skills of industrial sites, including programming skills and hardware. Currently, embedded system education offers a variety of education centered on Aduino, but this is mostly for beginners and is not sufficient for majors. In addition, while various prototype studies related to embedded systems are active, the training and training programs for working-level human resources needed at industrial sites are very scarce. Therefore, in order to foster the working personnel of the embedded system for the application of smart manufacturing, this paper selected the capability unit through in-depth interviews and survey analysis of 10 experts based on NCS, and developed education and training programs and contents.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.92-100
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• 2008

The existing transportation systems is emerged as a major obstacle to solve the problems such as a traffic jam and the increasing cost for a distribution and a traffic safety. In hun, ITS targeting intellectual vehicles and transportation infrastructure like road and signals is getting more important and the standards of ITS wireless communication is also getting attention. New traffic control strategies are being developed to utilize real-time traffic information collected by detection method using ITS wireless technology. Especially, DSRC system is being expanded wit ETCS and the use of OBU is spreading. These infrastructures will have much influence on ITS industry and a profound study on the method of utilizing a present infrastructure is going on in various fields. The optimum traffic signal control system using quality real-time information through these infrastructure is under development and so is WISDOM. Accordingly, this paper proposes communication protocol utilizing DSRC to collect real-time traffic information in WISDOM.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.201-202
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• 2018

자동차 부품산업은 자동차산업의 후방산업으로 완성차 메이커 제조산업의 조립용인 중간재 산업으로 부품의 품질에 따라 완성차의 성능이 좌우된다. 자동차 산업구조상 완성차에 종속적인 사업구조로 부품사의 독자 성장이 어렵고 수익성이 완성차업체에 종속 된다. 자동차부품사의 대형화 및 생산공정 자동화 변화로 기존의 수직계열화된 부품 공급 관계에도 변화가 예상되며, 완성차업체는 통합적인 시스템 부품을 생산할 수 있는 글로벌 대형 부품업체에 의존하는 상황이 전개될 수도 있다. 이와 같은 위기와 변화를 극복하기 위해 본 연구에서는 산업구조분석을 자동차 부품산업에 적용하여 자동차부품산업의 경쟁력제고 전략을 도출하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.91-98
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• 2010

Advances in communications and control technology, the strengthening of the Internet, and the growing recognition of the urgency to reduce the risk and production cost are motivating the development of improvements in the traditional manufacturing industry. In this paper, we developed a remote dust collector bag control system which is a combination of advanced IT and traditional dust collector based on the event. At first, we made the A/D(Analog/Digital) converter using a micro processor because the differential pressure transmission, which is a sensor of the dust collector, produces analog volt data. A/D converter can provide RS-232 communication to connect with Power Line Communication(PLC) modem. And, n-bytes message format was defined for the efficient dust collector bag information transmission from a dust collector to a user. Also, we designed the data types to model the dust collector and the dust collector bag, and they were logically modeled using XML and object-oriented modeling method. In addition to that, we implemented the system for showing the dust collector bag exchange time exactly to users at real-time using various visual user interfaces.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.57.3-57.3
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• 2018

KVN 수신기는 22/43/86/129GHz 주파수 대역의 우주전파를 관측할 수 있는 4채널 동시 관측 시스템의 핵심으로 다수의 제어 및 모니터 항목이 존재한다. 대표적인 예로 Synthesizer, Pcal, LO, Vacuum, Cryogenic Temperature 등이 있으며 이와 관련된 여러 인스트루먼트가 21m 전파망원경의 하부단에 위치한 수신기실 내에 분산 배치되어 있다. 이에 대한 효율적인 제어를 위해서는 사용자 컴퓨터 관점에서 두 가지 조건이 충족되어야 한다. 첫째, 물리적으로 분산된 인스트루먼트에 대한 접근 및 변경이 용이해야 하고, 둘째는 단일 인터페이스 상에서 다양한 인스트루먼트를 하나로 통합하는 확장성이 보장되어야 한다. 이러한 요건을 고려하여 KVN은 산업 분야에서 널리 쓰이고 있는 프로피버스를 수신기 시스템의 제어를 위한 기반 인터페이스로 활용 중에 있고, 추가 기능 요구에 효율적으로 대처하고 있다. 본 발표에서는 먼저 KVN 수신기 시스템을 구성하는 인스트루먼트에 대해 살펴보고자 한다. 그리고 이를 효율적으로 제어하기 위한 기반 인터페이스로서 프로피버스 구축 및 활용 현황에 대해 논하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.289-290
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• 2021

Recently, with the advent of the 4th industrial revolution, the role of robots is increasing, and the use of robots is also increasing in the service field. The most popular model for nonlinear research related to robots is the inverted pendulum system. A balancing robot using an inverted pendulum system is a representative nonlinear system and is mainly used to study control theory and other kinematic structures. In this paper, the state of the robot is measured using the 3-axis acceleration sensor (ADXL345) and 3-axis digital output gyro sensor (ITG-3200) or HMC5883L required for balancing robot control, and using the ESP32-WROOM-32 module. I want to design an MCU module that can control a balancing robot. In addition, by using the ESP32-WROOM-32 MCU module, we intend to design an MCU module that can monitor the state of the balancing robot based on WiFi or Bluetooth.