• Journal of Surface Science and Engineering
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• v.43 no.3
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• pp.159-164
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• 2010

Surface roughness of deposited or etched film strongly depends on ion bombardment. Relationships between ion bombardment variables and surface roughness are too complicated to model analytically. To overcome this, an empirical neural network model was constructed and applied to a deposition process of silicon nitride (SiN) films. The films were deposited by using a pulsed plasma enhanced chemical vapor deposition system in $SiH_4$-$NH_4$ plasma. Radio frequency source power and duty ratio were varied in the range of 200-800 W and 40-100%. A total of 20 experiments were conducted. A non-invasive ion energy analyzer was used to collect ion energy distribution. The diagnostic variables examined include high (or) low ion energy and high (or low) ion energy flux. Mean surface roughness was measured by using atomic force microscopy. A neural network model relating the diagnostic variables to the surface roughness was constructed and its prediction performance was optimized by using a genetic algorithm. The optimized model yielded an improved performance of about 58% over statistical regression model. The model revealed very interesting features useful for optimization of surface roughness. This includes a reduction in surface roughness either by an increase in ion energy flux at lower ion energy or by an increase in higher ion energy at lower ion energy flux.

• Journal of Korea Multimedia Society
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• v.22 no.7
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• pp.790-803
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• 2019

The effects of different heat treatments on the sensory characteristics of abalones are studied in this study. In this paper, the sensory evaluation of abalone samples under different heat treatment conditions is carried out, and the evaluation results are analyzed. The three-dimensional (3D) scanning and reverse engineering are used in tooth modeling of the sensory evaluation of abalone samples under different heat treatment conditions. Besides, the chewing movement models are simplified into three modes, including the cutting mode, compressing mode and grinding mode, which are simulated using finite element simulation. The elastic modulus of the abalone samples is obtained through the compression testing using a texture analyzer to distinguish their material properties under different heat treatments and to obtain simulated mechanical parameters. Finally, taking the mechanical parameters of the finite element simulation of abalone chewing as input and sensory evaluation parameters as the output, BP neural network is established in which the sensory texture evaluation model of abalone samples is obtained. Through verification, the neural network prediction model can meet the requirements of food texture evaluation, with an average error of 9.12%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.641-648
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• 2013

ARP spoofing is a typical Internet attack, in which an attacker sends data by changing his's MAC address with the other's one. Currently, this attack is usually dealt with separating the attacking PCs infected with ARP spoofing virus, by keeping network devices investigating by the network manager. However, this manual process has some limitations in time and accuracy. This paper proposes a new network management system to replace the effort of network manager who has to keep on inspecting the network. Along with designing an ARP analyzer and a disconnection notifier and adding them into the existing network management system, the proposed system provides a basement to identify and notify the PC infected by an ARP spoofing virus with fast and high accuracy. As a result, it is expected to minimize the network break off and to make easy the network management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.295-302
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• 2011

Ubiquitous is an information communication environment which peoples could connect on network without being conscious of the network and computer condition at anytime and anywhere. Presently, advanced technology, digital cities and eco-friendly cities using Ubiquitous technology are being focused through out the world. As recent information industry and communication technology have developed remarkably, studies on intelligent structures and structural maintenance methods by combining a general idea of connecting all objects on network by interpolating computers which is called Ubiquitous Computing, and USN(Ubiquitous Sensor Network) are being attempted. In this paper, a basic experiment on penetration of RF(Radio Frequency) sensor nodes using an experimental sample setting concrete and reinforcing bar as variables is studied to estimate the possibility of applying wireless sensor networks in structures. The spring of reinforcing bars, concrete thickness, intensity of radio frequency were set up as variables, transmitting and receiving distance were checked vertically and horizontally. Moreover, Spectrum Analyzer was used for checking the magnitude of the frequency used in order to measure the reduction of radio wave exactly. The radio wave reduction was numerically analyzed, and the influence of the wavelength was analysed as well. As a result, the penetration depth in concrete without reinforcing bars was 45cm, and in reinforced concretes which reinforcing bars placed at spacing of 5cm and 15cm, the penetration depth were 37cm and 45cm each. No influence on radio wave penetration depth were found when the spacing of reinforcing bars in the reinforced concrete structures becomes over 15cm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.125-130
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• 2017

Since field control equipment such as PLC has no function to log key event information in the log, it is difficult to analyze the accident. Therefore, it is necessary to secure information that can analyze when a cyber accident occurs by logging the main event information of the field control equipment such as PLC and IED. The protocol analyzer is required to analyze the field control device (the embedded device) communication protocol for event logging. However, the conventional analyzer, such as Wireshark is difficult to process the data identification and extraction of the large variety of protocols for event logging is difficult analysis of the payload data based and classification. In this paper, we developed a system for Big Data based on field control device communication protocol payload data extraction for event logging of large studies.

• Spatial Information Research
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• v.22 no.3
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• pp.1-8
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• 2014

While SNS services such as Twitter or Facebook are rapidly growing, research for the SNS analysis has been concerned. Especially, twitter reacts to social issues in real-time so that it is used to get useful experimental data for researchers of social science or information retrieval. However, it is still lack of research on the methodology to collect data. Therefore, this paper suggests the tweet acquisition system by considering tendency of twitter user oriented location-based event and political social event. First the system acquires tweets including information of location and keyword about event and secure IDs for acquisition of political social event. Then we plan ID-analyzer to classify the tendency of users. In addition for measuring reliability of ID-analyzer, it acquires and analyzes the tweet by using high-ranked ID. In analyses result, top-ranked ID shows 88.8% reliability, 2nd-ranked ID shows 76.05% and ID-analyzer shows 77.5%, it shortens collection time by using minority ID.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.310-315
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• 2013

This paper presents a two-port time-domain reflectometry(TDR) measurement technique for extracting the complex propagation constant of a cross-linked polyethylene(XLPE) cable. For the extraction, a short pulse transmitted through the cable is measured in the time domain and analyzed in the frequency domain. The propagation constant of a 22.9 kV XLPE cable with a conductor area of 325 $mm^2$ is extracted up to a frequency of approximately 2.14 GHz. The $S_{21}$ measured using a network analyzer and the two-port TDR technique are compared for verification. As a result compared with previous TDR method, the upper possible frequency limit for extracting the propagation constant increases and the measurement error decreases.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.65-69
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• 2003

Microstructural and electromagnetic properties of YIG ferrites, (Y, Ca)-(Fe, V, In, Al)-O for Isolator/Circulator were investigated with the sintering temperature. YIG ferrites of $Y_{2.1}Ca_{0.9}Fe_{4.4}V_{0.5}In_{0.05}Al_{0.05}O_{12}$ were fabricated by sintering at $1300^{\circ}C$, $1330^{\circ}C$, $1350^{\circ}C$, $1370^{\circ}C$. Crystallographic and microstructural properties were measured using XRD and SEM. Saturation magnetization$(4{\pi}M_s)$ were measured using VSM, and FMR(Ferromagnetic Resonance) experiment was conducted to measure ferromagnetic resonance line width$({\Delta}H)$. Microwave characteristics of YIG ferrites were measured using a Network Analyzer. The YIG ferrite of $Y_{2.1}Ca_{0.9}Fe_{4.4}V_{0.5}In_{0.05}Al_{0.05}O_{12}$, sintered at $1350^{\circ}C$, showed higher density, saturation magnetization and lower ferromagnetic resonance line width than those sintered at any other temperature.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.47-47
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• 2003

Abstract: RF Birdcage Resonator는 높은 자장 균질성과 신호 대 잡음비의 특성이 좋음으로 인해 MRI와 MRS 연구에 보편적으로 사용되고 있다. 본 연구는 인체를 비롯한 동물실험을 위한 다양한 실험대상에 따라 코일의 크기를 예측하여 Birdcage Resonator를 개발하였다. Unloaded와 Loaded 상태에서의 전기적인 성향을 Lumped Element Circuit Theory를 따라 일반적인 분석을 하였을 뿐 아니라 실제적인 실험을 통한 분석도 하였다. Introduction: Birdcage Resonator 는 자장 균일성이 뛰어나고 신호대잡음비가 좋아 Magnetic Resonance Imaging과 Spectroscopy에 유용하게 사용되어지고 있다. 이 연구에서는 실험대상에 따른 여러 가지의 Birdcage Resonator를 개발하기 위해 Lumped Element Circuit Theory를 사용한 일반적인 이론적 방법론을 이용하여 코일을 분석하였을 뿐 아니라 실제 제작한 후 실험을 통한 실질적인 영상분석도 병행하여 진행하였다. Method: 실질적인 개발에 앞서 Lumped Element Circuit Theory를 통해 이론적인 분석으로부터 나온 여러 parameter들을 정리하였다. 제작 후 실험적인 분석은 Network Analyzer (HP 4195A, 미국)를 통한 1차적인 분석을 한 후 최종적으로 3T MRI 장비 (메디너스, 한국)에서 수행하였다. 제작된 Birdcage Resonator의 종류는 기본적으로 Low-Pass Filter를 적용한 12-column 구조이다. 각각의 직경과 element의 길이는 다음과 같다. 1) 직경 13cm, element의 길이 22cm, 2) 직경 15cm, element의 길이 22cm, 3) 직경 17 cm, element의 길이 25cm. Result and Discussion: 여러 parameter들을 이론적으로 계산하여 실제 Birdcage Resonator를 제작하여 실험적인 분석을 한 결과 많은 차이가 있음을 알 수 있었다. 그 이유는 이론적인 계산에서는 생각되지 않았던 요인들이 실제 제작에 있어서는 많은 영향을 미쳤기 때문인 것이다. Network Analyzer를 통한 1차적인 분석 후에도 실제의 Magnet Field내에서 또 다시 차이가 나는 것 또한 같은 이유에서이다. 그러므로 Birdcage Resonator 제작에 있어서 이러한 여러 요인들을 충분히 고려하여야 할 것이다. Acknowledgement: 본 연구는 2002 년도 한국과학재단 목적기초연구사업 (과제번호 : R0l-2002-000-00294-0 (2002) 지원아래 수행되었다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.133-142
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• 2004

Recently, the growth of Internet and a variety of multimedia services through Internet increasingly demands high-speed packet transmission, the new routing function, and QoS guarantee on conventional routers. Thus, a new switching mechanical called the MPLS(Multi-Protocol Label Switching), was proposed by IETF(Internet Engineering Task Force) as a solution to meet these demands. In addition the deployment of MPLS network supporting Differentiated Services is required. In this paper, we propose the architecture of the MPLS switch supporting Differentiated Services in the MPLS-based network. The traffic conditioner consists of a classifier, a meter, and a marker. The VOQ-PHB module, which combines input Queue with each PHB queue, is implemented to utilize the resources efficiently. It employs the Priority-iSLIP scheduling algorithm to support high-speed switching. We have designed and verified the new and fast hardware architecture of VOQ-PHB and the traffic conditioner for QoS and high-speed switching using NS-2 simulator. In addition, the proposed architecture is modeled in VHDL, synthesized and verified by the VSS analyzer from SYNOPSYS. Finally, to justify the validity of the hardware architecture, the proposed architecture is placed and routed using Apollo tool.