• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1204-1212
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• 2008

This study enables to troubleshoot the problems of the existing dual system with the help of the implementation of totally dualized fault-tolerant system to L-CTC computer and HADAX, and equipments are simplified and systems are modernized with the addition of the control function, as a upgraded LCP control system, to L-CTC computer on the basis of WINDOWS based O/S switched from DOS environment. An error on Microlok, which is aninterlocking apparatus, forwarded to L-CTC computer ensures to handle the false data during the operation of the system. This paper discusses a sure way to prevent the deterioration of (SMRT) L-CYC system and to bolster its stability with formation of the dual system. Additionally, WINDOW based O/S consisting of L-CTC computer leads to simplification and modernization of facilities and enhances maintenance functions offering centralization for branch offices and machine rooms as well.

• Advances in nano research
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• v.7 no.3
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• pp.209-221
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• 2019

Graphene, with impressive electronic properties, have high potential in the microelectronic field. However, graphene itself is a zero bandgap material which is not suitable for digital logic gates and its application. Thus, much focus is on graphene nanoribbons (GNRs) that are narrow strips of graphene. During GNRs fabrication process, the occurrence of defects that ultimately change electronic properties of graphene is difficult to avoid. The modelling of GNRs with defects is crucial to study the non-idealities effects. In this work, nearest-neighbor tight-binding (TB) model for GNRs is presented with three main simplifying assumptions. They are utilization of basis function, Hamiltonian operator discretization and plane wave approximation. Two major edges of GNRs, armchair-edged GNRs (AGNRs) and zigzag-edged GNRs (ZGNRs) are explored. With single vacancy (SV) defects, the components within the Hamiltonian operator are transformed due to the disappearance of tight-binding energies around the missing carbon atoms in GNRs. The size of the lattices namely width and length are varied and studied. Non-equilibrium Green's function (NEGF) formalism is employed to obtain the electronics structure namely band structure and density of states (DOS) and all simulation is implemented in MATLAB. The band structure and DOS plot are then compared between pristine and defected GNRs under varying length and width of GNRs. It is revealed that there are clear distinctions between band structure, numerical DOS and Green's function DOS of pristine and defective GNRs.

• Imaging Science in Dentistry
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• v.53 no.1
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• pp.43-51
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• 2023

Purpose: This study aimed to assess texture analysis(TA) of cone-beam computed tomography (CBCT) images as a quantitative tool for the differential diagnosis of odontogenic and non-odontogenic maxillary sinusitis(OS and NOS, respectively). Materials and Methods: CBCT images of 40 patients diagnosed with OS (N=20) and NOS (N=20) were evaluated. The gray level co-occurrence (GLCM) matrix parameters, and gray level run length matrix texture (GLRLM) parameters were extracted using manually placed regions of interest on lesion images. Seven texture parameters were calculated using GLCM and 4 parameters using GLRLM. The Mann-Whitney test was used for comparisons between the groups, and the Levene test was performed to confirm the homogeneity of variance (α=5%). Results: The results showed statistically significant differences(P<0.05) between the OS and NOS patients regarding 3 TA parameters. NOS patients presented higher values for contrast, while OS patients presented higher values for correlation and inverse difference moment. Greater textural homogeneity was observed in the OS patients than in the NOS patients, with statistically significant differences in standard deviations between the groups for correlation, sum of squares, sum of entropy, and entropy. Conclusion: TA enabled quantitative differentiation between OS and NOS on CBCT images by using the parameters of contrast, correlation, and inverse difference moment.

• Journal of Astronomy and Space Sciences
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• v.41 no.3
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• pp.195-208
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• 2024

As human exploration goals shift from missions in low Earth orbit (LEO) to long-duration interplanetary missions, radiation protection remains one of the key technological issues that must be resolved. The low Earth orbit space radiation dosimeter (LEO-DOS) instrument to measure radiation levels and create a global dose map in the LEO on board the the next generation small satellite-2 (NEXTSat-2) was launched successfully on May 25, 2023 using the Nuri KSLV-III in Korea. The NEXTSat-2 orbits the Earth every 100 minutes, in an orbit with an inclination of 97.8° and an altitude of about 550 km above sea level. The LEO-DOS is equipped with a particle dosimeter (PD) and a neutron spectrometer (NS), which enable the measurement of dosimetric quantities such as absorbed dose (D), dose equivalent (H) for charged particles and neutrons. To verify the observations of LEO-DOS, we conducted a radiation dose estimation study based on the initial results of LEO-DOS, measured from June 2023 to September 2023. The study considered four source categories: (i) galactic cosmic ray particles; (ii) the South Atlantic Anomaly region of the inner radiation belt (IRB); (iii) relativistic electrons and/or bremsstrahlung in the outer radiation belt (ORB); and (iv) solar energetic particle (SEP) events.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.3
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• pp.153-161
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• 2011

In this work, we report the physics-based SPICE model of amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) and demonstrate the SPICE simulation of amorphous InGaZnO (a-IGZO) TFT inverter by using Verilog-A. As key physical parameter, subgap density-of-states (DOS) is extracted and used for calculating the electric potential, carrier density, and mobility along the depth direction of active thin-film. It is confirmed that the proposed DOS-based SPICE model can successfully reproduce the voltage transfer characteristic of a-IGZO inverter as well as the measured I-V characteristics of a-IGZO TFTs within the average error of 6% at $V_{DD}$=20 V.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.6
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• pp.709-715
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• 2006

The effects of thermal cycle condition and applied stress on the intergranular corrosion in austenitic 316 type stainless steels were investigated. Specimens were solution-treated at 1100$^{\circ}C$ for one hour and then sensitized in the temperature range of $500{\sim}800^{\circ}C$ by holding $2{\sim}300s$ with a various applied stresses of $0{\sim}8kg/mm^2$. Degree of sensitization. DOS %, was measured through polarization curve by electrochemical DL-EPR test. Microstructural observations were also conducted DOS % increased with an increase of sensitization temperature and/or holding time. Increase of applied stress resulted in increase of DOS % and more corroded surface because of acceleration of intergranular corrosion and fine grain size due to the stress. Cr depleted zone near grain boundary was observed. The amount of depletion was profounded with an increase of sensitization temperature, holding time and applied stress. $M_{23}C_6$ carbides were precipitated discontinuously at grain boundary. However, its amount was relatively small in the thermal cycle condition of 800$^{\circ}C$, 300sec and 4kg/mm$^2$.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.373-380
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• 1997

In order to implement the real-time operating systems for robot controller, this paper proposes a systematic method for implementing the real-time kernel under the DOS environment. So far, we designed the robot control software and its own operating system simultaneously. Though robot operating systems have simple structure, it allows the developer to have a surplus time and effort to implement complete robot systems. In addition to this, in most cases of this type, operating systems does not support multitasking function, thus, low level hardware interrupts are used for real-time execution. Subsequently, some kinds of real-time tasks are hard to implement under this environment. Nowadays, the operating systems for robot controller requires multitasking functions, intertask communication and task synchronization mechanism, and rigorous real-time responsiveness. Thus, we propose an effective and low costs real-time systems for robot controller satisfying the various real-time characteristics. The proposed real-time systems are verified through real implementation.

• Carbon letters
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• v.16 no.2
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• pp.116-120
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• 2015

We investigated the adsorption of Na on graphene and graphene oxide, which are used as anode materials in sodium ion batteries, using density functional theory. The adsorption energy for Na on graphene was -0.507 eV at the hollow sites, implying that adsorption was favorable. In the case of graphene oxide, Na atoms were separately adsorbed on the epoxide and hydroxyl functional groups. The adsorption of Na on graphene oxide-epoxide (adsorption energy of -1.024 eV) was found to be stronger than the adsorption of Na on pristine graphene. However, the adsorption of Na on graphene oxide-hydroxyl resulted in the generation of NaOH as a by-product. Using density of states (DOS) calculations, we found that the DOS of the Na-adsorbed graphene was shifted down more than that of the Na-adsorbed graphene oxide-epoxide. In addition, the intensity of the DOS around the Fermi level for the Na-adsorbed graphene was higher than that for the Na-adsorbed graphene oxide-epoxide.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.297-300
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• 2017

본 연구는 기술수용모델(Technology Acceptance Model)을 기반으로 <클림트 인사이드(2017)>전시에서 사용된 <스토클렛 저택의 장식벽화(Stoclet Frieze)> VR 앱에 대한 인지된 유용성(이하 PU)과 인지된 이용용이성(이하 PEOU)의 평가에 초점을 맞추었다. VR 앱의 학습적합성(SFL)이 감상적합성(SFA)보다 높게 평가된 PU의 경우, 학습유용성(UFL)과 감상유용성(UFA)의 모든 요인이 만족도(DOS)에 긍정적인 영향을 미침으로써, 전시환경에서의 VR 앱의 학습에 대한 내적 동기 부여 및 감상 지원에 대한 잠재력이 확인되었다. 또한 PEOU의 모든 요인들은 DOS뿐만 아니라 DOI와도 유의미한 상관관계를 가졌다. 본 연구를 통해 TAM의 PU와 PEOU의 ATUA(DOS 및 DOI) 및 BITUA(ITRA(1) 및 ITRA(2))에 대한 영향력이 검증됨에 따라, 두 변수는 사용자의 VR 앱에 대한 기술 수용에 대한 예측을 가능케 했으며, 결론적으로 예술작품 원작을 재매개한 VR 앱에 대한 평가모델로써 TAM의 적합성이 입증되었다.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.31-37
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• 2013

Mobile ad hoc networks (MANET) refers to a network designed for special applications for which it is difficult to use a backbone network. In MANETs, applications are mostly involved with sensitive and secret information. Since MANET assumes a trusted environment for routing, security is a major issue. In this paper we analyze the vulnerabilities of a pro-active routing protocol called optimized link state routing (OLSR) against a specific type of denial-of-service (DOS) attack called node isolation attack. Analyzing the attack, we propose a mechanism called enhanced OLSR (EOLSR) protocol which is a trust based technique to secure the OLSR nodes against the attack. Our technique is capable of finding whether a node is advertising correct topology information or not by verifying its Hello packets, thus detecting node isolation attacks. The experiment results show that our protocol is able to achieve routing security with 45% increase in packet delivery ratio and 44% reduction in packet loss rate when compared to standard OLSR under node isolation attack. Our technique is light weight because it doesn't involve high computational complexity for securing the network.