• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.443-448
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• 1996

In this paper, the 100 % non-inductive current drive scenarios are addressed for the steady-state operation on KT-2 tokamak, with the profile control using fast wave and lower hybrid wave as the external tools. Considering the stability, the well-aligned current profiles with a reversed-shear and $q_{min}$ > 2.0 has been favor-able in high ${\beta}_{p}$ plasma, together with a possibly higher bootstrap current fraction. Therefore, the effects of the auxiliary heating power profile on the control of MHD favorable current profile are evaluated in detail.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.117-120
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• 2002

An experimental research has been carried out for flow control of the shock wave/turbulent boundary-layer interaction utilizing aeroelastic mesoflaps. Various shapes and thicknesses of the mesoflap are tested to achieve different deflections of the flap, and ail the results are compared to the solid-wall reference case without flow-control mechanism. Quantitative variation of skin friction has been measured downstream of the interactions using the laser interferometer skin friction meter, and qualitative skin friction distribution has been obtained by observing the interference fringe pattern on the oil-film surface. A strong spanwise variation in the fringe patterns with a narrow region of separation near the centerline is noticed to form behind the shock structure, which phenomenon is presumed partially related to three-dimensional flow structures associated with both the sidewalls and the bottom test surface. The effect of the shape of the cavity is also observed and it is noticed that the shape of the cavity is not negligible.

• Advances in aircraft and spacecraft science
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• v.3 no.3
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• pp.299-315
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• 2016

In this work, a strategy for passive vibration control of periodic structures is proposed which involves adding a periodic array of simple resonant devices for creating band gaps. It is shown that such band gaps can be generated at low frequencies as opposed to the well known Bragg scattering effects when the wavelengths have to meet the length of the elementary cell of a periodic structure. For computational purposes, the wave finite element (WFE) method is investigated, which provides a straightforward and fast numerical means for identifying band gaps through the analysis of dispersion curves. Also, the WFE method constitutes an efficient and fast numerical means for analyzing the impact of band gaps in the attenuation of the frequency response functions of periodic structures. In order to highlight the relevance of the proposed approach, numerical experiments are carried out on a 1D academic rod and a 3D aircraft fuselage-like structure.

• Journal of the Korean Geotechnical Society
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• v.25 no.9
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• pp.45-55
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• 2009

The quality of railroad trackbed fills has been controlled by field measurements of density and bearing resistance of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. To overcome the defect, the compressional wave velocity was adopted as a control measure, in parallel with the advent of the new design procedure, and its measurement technique was proposed in the preliminary investigation. The key concept of the quality control procedure is that the target value for field compaction control is the compressional wave velocity determined at optimum moisture content using modified compaction test, and direct-arrival method is used for the field measurements during construction, which is simple and reliable enough for practice engineers to access. This direct-arrival method is well-suited for such a shallow and homogeneous fill lift in terms of applicability and cost effectiveness. The sensitivity of direct-arrival test results according to the compaction quality was demonstrated at a test site, and it was concluded that compressional wave velocity can be effectively used as quality control measure. The experimental background far the companion study (Park et al., 2009) was established through field and laboratory measurements of the compressional wave velocity.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.11-18
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• 2011

Wave overtopping reef system with guide vanes convert incident wave energy on the reef type structures into electric power. Previous studies decided shape parameters likes slope, height of the sloping arm and shape of guide vane. In this paper, using these shape parameters produce 1/7 scale model and construct integration scale model system combining water pressure head turbine, power generation, power control, operating control and monitoring system. In these systems, we measure the overtopping and power generation with different wave heights and periods and compare the results with the previous studies. This was confirmed designed overtopping and power generation, then we suggest efficient control system.

• Journal of Biomedical Engineering Research
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• v.39 no.1
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• pp.55-61
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• 2018

The purpose of this study was to investigate the effect of a pillow simulated with cranial sacral therapy (CST) on sleep induction using electroencephalography (EEG). This study included 12 voluntary participants divided into experimental group (CST group) and control group (Non-CST group) to observe EEG changes. The position of the electrode for EEG measurement consists of 8 channels electrodes (Fp1, Fp2, F3, F4, T3, T4, P3 and P4). In this study, we measured the fall asleep time, change of brain activity and sleep wave ratio using EEG wave (${\delta}$, ${\theta}$, ${\alpha}$, ${\beta}$ and ${\gamma}$). As a result, the mean fall asleep time of the experimental group was shorter than that of the control group significantly (p < 0.001). Also in comparison with the control group, both the delta (d) and theta (q) wave corresponding to the slow waves showed a larger increase and the alpha (a) wave showed a larger decrease significantly. The slow waves of experimental group showed a higher rate of significant increase than the control group (p < 0.001). Therefore this study showed that pillow based on CST had an effective in improving sleep induction and quality.

• Korean Journal of Radiology
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• v.23 no.2
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• pp.237-245
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• 2022

Objective: Viscoelasticity is an essential feature of nerves, although little is known about their viscous properties. The discovery of shear wave dispersion (SWD) imaging has presented a new approach for the non-invasive evaluation of tissue viscosity. The present study investigated the feasibility of using SWD imaging to evaluate diabetic neuropathy using the sciatic nerve in a diabetic rat model. Materials and Methods: This study included 11 diabetic rats in the diabetic group and 12 healthy rats in the control group. Bilateral sciatic nerves were evaluated 3 months after treatment with streptozotocin. We measured the nerve cross-sectional area (CSA), nerve stiffness using shear wave elastography (SWE), and nerve viscosity using SWD imaging. The motor nerve conduction velocity (MNCV) was also measured. These four indicators and the histology of the sciatic nerves were then compared between the two groups. The performance of CSA, SWE, and SWD imaging in distinguishing the two groups was assessed using receiver operating characteristic (ROC) analysis. Results: Nerve CSA, stiffness, and viscosity in the diabetic group was significantly higher than those in the control group (all p < 0.05). The results also revealed a significantly lower MNCV in the diabetic group (p = 0.005). Additionally, the density of myelinated fibers was significantly lower in the diabetic group (p = 0.004). The average thickness of the myelin sheath was also lower in the diabetic group (p = 0.012). The area under the ROC curve for distinguishing the diabetic neuropathy group from the control group was 0.876 for SWD imaging, which was significantly greater than 0.677 for CSA (p = 0.030) and 0.705 for SWE (p = 0.035). Conclusion: Sciatic nerve viscosity measured using SWD imaging was significantly higher in diabetic rats. The viscosity measured using SWD imaging performed well in distinguishing the diabetic neuropathy group from the control group. Therefore, SWD imaging may be a promising method for the evaluation of diabetic neuropathy.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.57-61
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• 2006

As high speed internet users are tremendously increasing, three are keenly in need of development of high speed portable internet technology which can provide high quality wireless internet service cheaply even in the mobile. Unlike the FDD-CDMA, TDD-OFDMA has relatively poor wave environment with inducing interference, fading and delay because it agrees to multi-carrier modulation method and time-division radio telecommunication system. To solve this problem, it is necessary to develop repeater operating by digital signal processing method which have more strict wireless channel control and wave signal processing technology over TDD telecommunication equipments. This thesis is dealing with design and implementation of Digital RF Repeater which implemented 'Synchronization Acquisition Unit', 'TDD signal switching Unit', 'Feedback Signal Cancellation Unit'. Over this argument, we will develop digital RF repeater with more cheap, more adaptive in wave environment like oscillation control, adaptive wave monitoring and output increasing and having control function as a result it will be helpful for success in high speed portable internet service business.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.3
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• pp.35-44
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• 2002

In this paper, the analytic studies on the wave control performance of moored pontoon-type floating breakwater are presented. A two-dimensional eigenfunction expansion method is adopted to study the motion responses and the transmission coefficients of pontoon-type floating breakwater in beam waves. The stiffness coefficients of mooring line are idealized as linear elastic spring. Comparison of the analytical results with a numerical results (FEM) shows good agreement over a wide range of frequencies. The performance of mooed pontoon-type floating breakwater is tested with various design parameters such as sectional geometry, mooring line characteristics and wave frequencies. It is found that the properly designed floating breakwater can be an effective wave control structure.

• Annals of Clinical Neurophysiology
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• v.4 no.2
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• pp.108-113
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• 2002

Background and Objective : Carpal tunnel syndrome (CTS) is the most common mononeuropathy encountered in clinical practice. No single procedure or group of procedures has demonstrated adequate sensitivity. F-wave study in CTS is very rarely reported. To determine the diagnostic usefulness of new parameters of F-wave and comparative study of F-wave parameters of median and ulnar nerves in patients with CTS. Methods : F-wave responses of median and ulnar nerves were analyzed from 27 patients with clinically diagnosed CTS and 22 age and gender-matched normal control. Conventional F-wave parameters were studied. Also, the usefulness of new parameters such as mean and maximal ulnar-median F-wave latency differences, ulnar-median F-wave persistence and chronodispersion differences, median/ulnar F-wave amplitude ratio, and F-wave conduction velocity (FCV) using mean and maximal latency were assessed. Results : Compared with controls, median F-wave minimal, maximal and mean latencies, mean F-wave amplitude/M-wave amplitude, minimal, mean and maximal ulnar-median F-wave latency differences, and FCVs using minimal, maximal and mean latency were significant (P<0.05~0.001). Median F-wave minimal, maximal and mean latencies, mean ulnar-median F-wave latency difference, and FCVs using minimal, maximal and mean latency showed high sensitivity and specificity. Mean ulnar-median F-wave latency difference and FCVs using maximal and mean latency were new parameters. Conclusion : New F-wave parameter including mean ulnar- median F-wave latency difference and FCVs using maximal and mean latency may be a useful to assess the CTS. Also, median F-wave minimal, maximal and mean latencies, and FCV using minimal latency may be included in routine diagnostic tests in CTS.