• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1529-1534
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• 2018

We used in-situ synchrotron X-ray scattering to investigate phase transformations of octahedral tilted monoclinic $SrRuO_3$ (MSRO) and tetragonal SRO (TSRO) thin films on $SrTiO_3$ (STO) substrates. The octahedral tilted MSRO thin films were highly crystalline and the monoclinic distortion angle was $0.45^{\circ}$. The phase transition temperature from the MSRO to TSRO phase occurred at approximately $200^{\circ}C$ as a second order transition. Conversely, no phase transformations of the TSRO thin film occurred within the range from RT to $250^{\circ}C$. The octahedral $RuO_6$ rotation was strongly affected by the phase transformation in the SRO thin films.

• 한국정밀공학회지
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• 제14권4호
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• pp.110-118
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• 1997

Multi-layer neural networks with error back-propagation algorithm have a great potential for identifying nonlinear systems with unknown characteristics. However, because they have a demerit that the speed of convergence is too slow, various methods for improving the training characteristics of backpropagition networks have been proposed. In this paper, a fuzzy division method is proposed to improve the convergence speed, which can find out an effective fuzzy division by the tuning of membership function and independently train each neural network after dividing the network model into several parts. In the simulations, the proposed method showed that the optimal fuzzy partitions could be found from the arbitray initial ones and that the convergence speed was faster than the traditional method without the fuzzy division.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.820-824
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• 2004

Personal Robot System in developing, have a module architecture, each module are connected through heterogeneors network systems like Ethernet, WLAN (802.11), IEEE1394 (Firewire), Bluetooth, USB, CAN, or RS-232C. In developing personal robot system we think that the key of robot performance is interoperability among modules. Each network protocol are well connected in the view of network system for the interoperability. So we make a bridging architecture that can routing, converting, transporting data packets with matcing each network's properties. Furthermore we suggest a advanced design scheme for realtime / non-realtime and control signal (short, requiring hard-realtime) / multimedia data (large, requiring soft-realtime). By some application systems, we could test performance, interoperability and stability. In this paper, we show our design concept, middleware architecture, and some applications systems using this middleware.

• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.351-356
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• 2015

Visible light communication (VLC) is considered to be an attractive scheme to realize the broadband wireless communication for an indoor environment. We present a room division multiplexing (RDM) mechanism for an indoor multi-room VLC network, which utilizes the spatial position of the LED lamp in different rooms as a novel dimension of network resource for multiplexing, and thus the network capacity is increased. In such a network, the service interruption caused by user cross-room movement is an important problem, and we propose a double-area-positioning based cross-room switch solution. An experimental platform demonstrates the RDM-deployed VLC network, and validates the performance of the presented switch mechanism.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1159-1164
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• 2006

In this paper an artificial neural network model is developed to estimate the unconfined compression strength of Deep Cement Mixing(DCM) treated soil. A database which consists of a number of unconfined compression test result compiled from 9 clay sites is used to train and test of the artificial neural network model. Developed neural network model requires water content of soil, unit weight of soil, passing percent of #200 sieve, weight of cement, w-c ratio as input variables. It is found that the developed artificial neural network model can predict more precise and reliable unconfined compression strength than the conventional empirical models.

• 경영과정보연구
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• 제38권1호
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• pp.1-21
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• 2019

본 연구는 최고경영자와 이사회의 네트워크밀도와 R&D투자 간의 관계와 이들 관계에 영향을 미칠 수 있는 기업분할의 유형과 제도의 영향을 분석하는데 주된 목적을 두고 실행되었다. 연구목적의 달성을 위해 외환위기가 발생하고 기업분할 관련법(상법 530조)이 제정된 직후인 1999년부터 가장 최근의 자료수집이 가능한 2016년까지 총 18년의 연구기간 동안 기업분할을 실행한 국내기업들을 대상으로 다중회귀분석을 실행하였다, 분석결과는 국내기업 최고경영자와 이사회의 네트워크밀도와 R&D투자 간에 유의한 정(+)의 관계가 있음을 보여주고 있다. 또한 기업분할 유형과 관련하여 최고경영자와 이사회의 네트워크밀도와 R&D투자 간의 정의 관계는 비관련분할에서 보다 관련분할을 실행한 기업에서 강화되었음을 보여주고 있으며, 기업분할 제도와 관련해서는 물적분할보다 인적분할을 실행한 기업들에서 이들 관계가 강화되었음을 보여주고 있다. 신속한 의사결정이 요구되는 사안임에도 불구하고 장기적인 관점에서 높은 수준의 불확실성과 위험을 수반하게 되는 R&D투자결정에 있어 최고경영자와 이사회 간의 네트워크밀도가 긍정적인 영향을 미칠 수 있음을 보여주는 본 연구의 분석결과는 최고경영진들 간의 신뢰의 중요성을 강조해 온 네트워크이론의 주장과 일치한다. 또한 혁신역량 강화를 위한 R&D투자결정에 있어 개인수준의 요인들뿐만 아니라 조직수준의 요인이 함께 고려되어야 함을 시사하고 있다. 본 연구는 향후 기업분할의 활용을 통한 보다 전략적인 국내기업 지배구조의 개선방안에 대한 연구를 강화하는 동기를 제공해 줄 수 있을 것으로 기대된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2097-2100
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• 2003

Many studies have been done on secure operating system using secure kernel that has various access control policies for system security. Secure kernel can protect user or system data from unauthorized and/or illegal accesses by applying various access control policies like DAC(Discretionary Access Control), MAC(Mandatory Access Control), RBAC(Role Based Access Control), and so on. But, even if secure operating system is running under various access control policies, network traffic among these secure operating systems can be captured and exposed easily by network monitoring tools like packet sniffer if there is no protection policy for network traffic among secure operating systems. For this reason, protection for data within network traffic is as important as protection for data within local system. In this paper, we propose a secure operating system trusted channel, SOSTC, as a prototype of a simple secure network protocol that can protect network traffic among secure operating systems and can transfer security information of the subject. It is significant that SOSTC can be used to extend a security range of secure operating system to the network environment.

• Journal of Advanced Marine Engineering and Technology
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• 제40권10호
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• pp.906-915
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• 2016

In this study, a network monitoring system, including a secure 460-Network and a 460-Gateway, is designed and developed according with the requirements of the IEC (International Electro-Technical Commission) 61162-460 network standard for the safety and security of networks on board ships. At present, internal or external unauthorized access to or malicious attack on a ship's on board systems are possible threats to the safe operation of a ship's network. To secure the ship's network, a 460-Network was designed and implemented by using a 460-Switch, 460-Nodes, and a 460-Gateway that contains firewalls and a DMZ (Demilitarized Zone) with various application servers. In addition, a 460-firewall was used to block all traffic from unauthorized networks. 460-NMS (Network Monitoring System) is a network-monitoring software application that was developed by using an simple network management protocol (SNMP) SharpNet library with the .Net 4.5 framework and a backhand SQLite database management system, which is used to manage network information. 460-NMS receives network information from a 460-Switch by utilizing SNMP, SNMP Trap, and Syslog. 460-NMS monitors the 460-Network load, traffic flow, current network status, network failure, and unknown devices connected to the network. It notifies the network administrator via alarms, notifications, or warnings in case any network problem occurs. Once developed, 460-NMS was tested both in a laboratory environment and for a real ship network that had been installed by the manufacturer and was confirmed to comply with the IEC 61162-460 requirements. Network safety and security issues onboard ships could be solved by designing a secure 460-Network along with a 460-Gateway and by constantly monitoring the 460-Network according to the requirements of the IEC 61162-460 network standard.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2004년도 추계학술대회
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• pp.37-41
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• 2004

The existing network can be expanded with addition of new nodes and multiple choices of link type for each nossible link. In this paper, the design problem of network expansion is defined as finding the network topology minimizing cost subject to reliability constraint. To efficiently solve the problem, an genetic algorithm approach is suggested.

• ETRI Journal
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• 제26권4호
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• pp.371-374
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• 2004

We propose and demonstrate a fabrication method of chirped fiber gratings by a thermal diffusion process. The method could suggest a direction for a simple and cost-effective implementation of chirped fiber grating-based devices.