• Journal of the Korean Society for information Management
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• v.18 no.3
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• pp.265-284
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• 2001

The aim of this study was to discover the correlation between users cognitive style and their attitude towards evaluating the system. Postgraduate students cognitive styles were defined as Verbaliser/Imager and Wholist/Analytic, and the functionality and ease of learning features of a Web-based OPAC(Online Public Access Catalogue) system were evaluated using a combined evaluation methods: interviews for the preliminary survey, a questionnaire far the central data collection, and a psychometric approach for the judgement of students cognitive style using Ridings CSA(Cognitive Style Assessment) tool. Forty-four postgraduate student volunteers responded and data was analysed using SPSS(Statistical Package for Social Science) for Windows. The statistical analysis of each feature of the evaluation, the correlation between the variables, and the features were explored using Pearsons correlation coefficients(r). In exploring the effects of the cognitive styles of individuals, this study has failed to reveal a significant (P < 0.05) correlations in the interactive Web-based OPACs evaluation. It could be said that the contribution of cognitive styles to evaluating Web-based OPACs is likely to be weaker than that of non-cognitive (or demographic) variables.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.9-18
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• 2016

The thermal and mechanical properties of fiber-reinforced cement-based composite for solar thermal energy storage were investigated in this paper. The effect of the addition of different cement-based materials to Ordinary Portland cement on the thermal and mechanical characteristics of fiber-reinforced composite was investigated. Experiments were performed to measure mechanical properties including compressive strength before and after thermal cycling and split tensile strength, and to measure thermal properties including thermal conductivity and specific heat. Test results showed that the residual compressive strength of mixtures with OPC and slag was greatest among cement-based composite. Thermal conductivity of mixtures including graphite was greater than that of any other mixtures, indicating favor of graphite for improving thermal transfer in terms of charging and discharging in thermal energy storage system. The addition of CSA or zirconium increased specific heat of fiber-reinforced cement-based composite. Test results of this study could be actually used for the design of thermal energy storage system in concentrating solar power plants.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.1
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• pp.60-67
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• 2016

A pressurized heavy water reactor (PHWR) designed to refuel in service produces the energy required by nuclear fission. The fuel channel consists of components such as a pressure tube which directly contacts the fuel and is a passage for the reactor coolant, a calandria tube which contacts the moderator and is rolled joint with calandria, and a spacer which is not to contact the pressure tube and a calandria tube. As the fuel channel is one of the most important equipments, it requires accurate and periodic inspections to assess the integrity of a reactor in accordance with CSA N285.4. A fuel channel inspection system is developed to inspect fuel channels during in-service inspection in Wolsong unit. In this paper, the results and considerations of a field test are presented in order to show the effectiveness of the developed fuel channel inspection system.

• Electronics and Telecommunications Trends
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• v.11 no.4 s.42
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• pp.13-25
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• 1996

본 고에서는 ADSL(Asymmetric Digital Subscriber Lines) 서비스를 DMT(Digital Multichannel Transmitter) 시스템 모델에 관하여 고찰한다. CSA(Carrier Service Area) 구역에서 6Mb/s급의 다중반송파변조방식(multi-carrier modulation)을 전송방식으로 하는 ADSL-3급 서비스가 가능한 가입자 루프 및 전송신호 특성을 고려한 설계 요구 조건을 살펴보고, 이를 만족하는 DMT ADSL 시스템 모델, 등화기 구조 및 DMT ADSL시스템의 성능예측방법을 고찰함으로써 보다 나은 성능의 ADSL시스템 구현을 위한 설계방향을 제시하고자 한다.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.270-278
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• 2011

The purpose of this study was to compare acute and chronic LBP patient in twenties and forties, respectively by size measure paraspinal muscle (cross-sectional area; CSA). CSA of paraspinal muscle (psoas, multifidus, erector muscle) size was measured by free-handling technique of the picture archiving and communication system(PACS) using MRI at the level(lower end-plate of L4) in twenties(9 males, 10 females) and forties(9 males, 8 females) in acute and chronic LBP patient. The results of this study showed no significantly difference between acute and chronic LBP (p>0.05) in twenties patients. However, there was significant difference between acute and chronic LBP (p<0.05) in forties patients. Also, there was significant difference in paraspinal muscle CSA between chronic LBP patients in twenties and chronic LBP patients in forties (p<0.05). This study showed that paraspinal muscle atrophy was observed in forties with various cause, but Not chronic LBP patients in twenties. Accordingly it is required for chronic LBP patients in forties to minimize trunk muscle atrophy through immediate back muscle dynamic exercise and early functional activity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.6
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• pp.476-481
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• 2014

In this paper, we design the pre-equalizer of transmitter circuit in order to enhancement modulation bandwidth of white LED which is light source of VLC (Visible Light Communication). Also, we eliminate yellow light component by optical filtering which mitigate frequency response of white LED. Power loss by optical filtering is overcome by using convex lens. By applying proposed system, 3 dB bandwidth deciding modulation bandwidth of white LED increases from 3 MHz to more than 25 MHz and the transmission distance increases by optical design which secure additional signal power. We optically modulate NRZ-OOK signal to LED and receive light signal using APD. We analyze received data using CSA and RFSA. As a result, we experimently demonstrate the possibility that transmits NRZ-OOK signal up to 30 Mbps in 4.5 m, 50 Mbps in 1.5 m through the pre-equalizer and optical design.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.278-281
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• 1995

In this paper, we have developed EEG (electroencephalography) analyzer for monitoring the condition of brain in neurological surgery. This system is composed of EEG amplifier. personal-computer and BSP (Digital Signal Processor). By parallel processing of DSP, this system can analysis the power spectral density change of EEG in real-time and display the CSA(Compressed Spectral Array) and CDSA(Color Density Spectral array) of EEG. This system was tested by real EEG and showed the change of EEG.

• Journal of The Korean Association For Science Education
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• v.30 no.8
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• pp.1097-1109
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• 2010

The purpose of this study is to analyze the ERF components patterns of observers who have different cognitive styles using magneto-encephalography (MEG). The task was developed based on the CSA (Cognitive Style Analysis) program. Eight right-handed, healthy male college students participated in voluntarily. To investigate college students' ERF components during the task, an MEG system with block design was used to measure magnetic signals in their brains. For examining the observation characteristic by cognitive style, MEG ERF components were analyzed. As a result, four ERF components (M1, M2, M3, M4) were observed. Through the results of this study, the reason for different observation characteristics by cognitive styles was verified in the neurophysiological methods. This study will have implications to establish theories on scientific observation and cognitive styles.

• Journal of Korean Neurosurgical Society
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• v.65 no.6
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• pp.801-815
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• 2022

Objective : To evaluate the stent apposition of a low-profile visualized intraluminal support (LVIS) device in distal internal carotid artery (ICA) aneurysms, examine its correlation with clinical and angiographic outcomes, and determine the predictive factors of ischemic adverse events (IAEs) related to stent-assisted coiling. Methods : We retrospectively analyzed a prospectively maintained database of 183 patients between January 2017 and February 2020. The carotid siphon from the cavernous ICA to the ICA terminus was divided into posterior, anterior, and superior bends. The anterior bends were categorized into angled (V) and non-angled (C, U, and S) types depending on the morphology and measured angles. Complete stent apposition (CSA) and incomplete stent apposition (ISA) were evaluated using unsubtracted angiography and flat-panel detector computed tomography. Dual antiplatelet therapy with aspirin 200 mg and clopidogrel 75 mg was administered. Clopidogrel resistance was defined as fewer responders (≥10%, <40%) and non-responders (<10%) based on the percent inhibition (%INH) of the VerifyNow system. These were counteracted by a dose escalation to 150 mg for fewer responders or substitution with cilostazol 200 mg for non-responders. IAEs included intraoperative in-stent thrombosis, transient ischemic attack, cerebral infarction, and delayed in-stent stenosis. A multivariate logistic regression analysis was used to determine the predictive factors for ISA and IAEs. Results : There were 33 ISAs (18.0%) and 27 IAEs (14.8%). The anterior bend angle was narrower in ISA (-4.16°±25.18°) than in CSA (23.52°±23.13°) (p<0.001). The V- and S-types were independently correlated with the ISA (p<0.001). However, treatment outcomes, including IAEs (15.3% vs. 12.1%), aneurysmal complete occlusion (91.3% vs. 88.6%), and recanalization (none of them), did not differ between CSA and ISA (p>0.05). The %INH of 27 IAEs (13.78%±14.78%) was significantly lower than that of 156 non-IAEs (26.82%±20.23%) (p<0.001). Non-responders to clopidogrel were the only significant predictive factor for IAEs (p=0.001). Conclusion : The angled and tortuous anatomical peculiarity of the carotid siphon caused ISA of the LVIS device; however, it did not affect clinical and angiographic outcomes, while the non-responders to clopidogrel affected the IAEs related to stent-assisted coiling.

• Structural Engineering and Mechanics
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• v.7 no.3
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• pp.241-257
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• 1999

This paper presents a procedure to minimize the cost of materials of cable-stayed bridges with composite box girder and concrete tower. Two sets of iterations are included in the proposed procedure. The first set of iteration performs the structural analysis for a cable-stayed bridge. The second set of iteration performs the optimization process. The design is formulated as a general mathematical problem with the cost of the bridge as the objective function and bending forces, shear forces, fatigue stresses, buckling and deflection as constraints. The constraints are developed based on the Canadian National Standard CAN/CSA-S6-88. The finite element method is employed to perform the complicated nonlinear structural analysis of the cable-stayed bridges. The internal penalty function method is used in the optimization process. The limit states design method is used to determine the load capacity of the bridge. A computer program written in FORTRAN 77 is developed and its validity is verified by several practical-sized designs.