• ETRI Journal
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• v.41 no.5
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• pp.648-657
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• 2019

A cluster topology was proposed with the assumption of zero noise to improve the performance of wireless body area networks (WBANs). However, in WBANs, the transmission power should be reduced as low as possible to avoid the effect of electromagnetic waves on the human body and to extend the lifetime of a battery. Therefore, in this work, we consider a bit error rate for a cluster-based WBAN and analyze the performance of the system while the transmission of sensors and cluster headers (CHs) is controlled. Moreover, a hierarchical topology is proposed for the cluster-based WBAN to further improve the throughput of the system; this proposed system is called as the hierarchical cluster WBAN. The hierarchical cluster WBAN is combined with a transmission control scheme, that is, complete control, spatial reuse superframe, to increase the throughput. The proposed system is analyzed and evaluated based on several factors of the system model, such as signal-to-noise ratio, number of clusters, and number of sensors. The calculation result indicates that the proposed hierarchical cluster WBAN outperforms the cluster-based WBAN in all analyzed scenarios.

• Smart Structures and Systems
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• v.14 no.4
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• pp.517-539
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• 2014

The combined use of smart materials, complementing each others' characteristics and resulting in devices with optimised features, is providing new solutions in many industries. The use of ingenious combinations of smart materials has led to improvements in actuation speed and force, signal-to-noise ratio, sensor precision and unique capabilities such as self-sensing self-healing systems and energy autonomy. This may all give rise to a revival for numerous families of smart materials, for which application proposals had already reached a stationary situation. It may also provide the boost needed for the definitive industrial success of many others. This study focuses on reviewing the proposals, preliminary studies and success cases related to combining smart materials to obtain multifunctional, improved systems. It also examines the most outstanding applications and fields for the combined use of these smart materials. We will also discuss related study areas which warrant further research for the development of novel approaches for demanding applications.

• Journal of radiological science and technology
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• v.47 no.2
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• pp.117-123
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• 2024

This study was to assessment of quality assurance (QA) and noise characteristics of Noise Power Spectrum (NPS) according to the time of by using electronic portal imaging device (EPID) for LINAC (Linear Accelerator). LINAC device was (Varian Clinac^R iX LINAC, USA) used and the were 40 × 30 cm² of detector size were 1024 × 768 photo-electric diode array size. Signal could be obtained the K-space image of white noise images for NPS and we used to Overlap, Non-Overlap, Out of Penumbra, Flatness, Symmetry, Symmetry Rt, Lt methods. The 2013s NPS image Out of Penumbra quantitatively value more than 2013s NPS image Symmetry Rt, Lt methods quantitatively NPS based on the frequency of 1.0 mm^-1. Thus, the 2022s NPS image Out of Penumbra quantitatively value more than 2022s NPS image Symmetry Rt, Lt methods quantitatively NPS based on the frequency of 1.0 mm^-1. The assessment of comparison of white noise for NPS image noise and intensity of this study were to that should be used efficiently of the LINAC EPID detector system for Overlap method for International Electro-technical Commission (IEC).

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.127-130
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• 2004

Analytical sensitivity on TDM test is the lowest concentration that can be distinguished from background noise. The aim of study was to evaluate analytical sensitivity that is also referred to as the lower limit of detection(LLD) about difference between zero calibrator and isotonic saline sample. We tested for 10 days with zero calibrators and 0.85% saline samples while running trilevel control samples under control. Raw data divided by two groups calculated mean and standard deviation from two sample populations and analytical sensitivity by ${\bar{X}}+2SD$. In comparison with isotonic saline samples and zero calibrators, there were significant differences in phenytoin, phenobarbital and vancomycin, etc. Especially analytical sensitivity on phenytoin is at the same level as the upper limit of analytical measurement range with $40{\mu}g/mL$. We think the cause of this is matrix interference. In conclusion, we were sure that standard protocol for analytical sensitivity as lower limit of analytical measurement range on TDM test must be measured with zero standard rather than an isotonic saline sample and type 1 reagent DW for reducing matrix effects within interactions between different materials in a mixture.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.37.1-37.1
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• 2021

For the first time in Korea, we are developing technology for gravitational wave (GW) detectors as a major R&D program. Our main research target is quantum noise reduction technology which can enhance the sensitivity of a GW detector beyond its limit by classical physics. Technology of generating squeezed vacuum state of light (SQZ) can suppress quantum noise (shot noise at higher frequencies and radiation pressure noise at lower frequencies) of laser interferometer type GW detectors. Squeezing technology has recently started being used for GW detectors and becoming necessary and key components. Our ultimate goal is to participate and make contribution to international collaborations for upgrade of existing GW detectors and construction of next generation GW detectors. This presentation will summarize our results in 2020 and plan for the upcoming years. Technical details will be presented in other family talks.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.175-181
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• 2011

We propose a novel algorithm for measuring the radius of tubes. This proposed algorithm is capable of effectively removing added noise and measuring the radius of tubes within allowable precision. The noise is removed by using a candidate true center that minimizes the standard deviation with respect to the radius. Further, the disconnection in data points resulting from noise removal is solved by using a connection algorithm. The final step of the process is repeated until the value of the standard deviation decreases to a small predefined value. Experiments were performed using circle geometries with added noise and a real tube with complex noise and that is used in the braking units of automobiles. It was concluded that the measurement carried out using the algorithm was accurate within 1.4%, even with 15% added noise.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.7
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• pp.710-721
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• 2013

The noise prediction of motor driving system is one of the most important parts in EV/HEV, as the number of power electronic devices increases. This paper describes the mechanism of noise making process and proposes a simulation model of motor driving system for the prediction of the conducted noise. Theoretical calculations and model based simulations were carried out. DOD-dependent-battery parameters were extracted by AC analysis, and an inverter model including dynamic diode was used. Furthermore, 2-D EM tool was used for the motor modeling and was combined with the circuit models of battery and inverter. The simulated voltages, currents and spectrums in the motor driving system showed qualitatively meaningful results, suggesting the validness of the suggested modeling methods.

• Journal of Korean Society for Quality Management
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• v.35 no.4
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• pp.52-60
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• 2007

A multi-attribute robust design methodology is presented. This method can be applied where there are various technical constraints in design variables, multiple potentially conflicting design attributes, and uncontrollable noise variables. Two forms of technical constraints, soft and hard constraints, are considered in robust design settings. Specifically, this work presents procedures for integrating two types of design constraints seamlessly on the multiple design attributes, which is achieved through a development of multi-attribute utility formulation. The effectiveness of the overall procedures is tested with the aid of an I-Beam design problem, and results of sensitivity analysis are discussed.

• Proceedings of the KSRS Conference
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• v.2
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• pp.736-739
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• 2006

While hyperspectral data are very rich in information, their processing poses several challenges such as computational requirements, noise removal and relevant information extraction. In this paper, the application of advanced scale-space filtering to selected hyperspectral bands was investigated. In particular, a pre-processing tool, consisting of anisotropic diffusion and morphological leveling filtering, has been developed, aiming to an edge-preserving smoothing and simplification of hyperspectral data, procedures which are of fundamental importance during feature extraction and object detection. Two scale space parameters define the extent of image smoothing (anisotropic diffusion iterations) and image simplification (scale of morphological levelings). Experimental results demonstrated the effectiveness of the developed scale space filtering for the enhancement and smoothing of hyperspectral remote sensing data and their advantage against watershed over-segmentation problems and edge detection.

• Wind and Structures
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• v.3 no.2
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• pp.117-132
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• 2000

Under special conditions of turbulent wind, suspension and cable-stayed bridges could reach instability conditions. In various instances the bridge deck, as like a bluff body, could exhibit single-degree torsional instability. In the present study the turbulent component of flow has been considered as a solution of a differential stochastic linear equation. The input process is represented by a Gaussian zero-mean white noise. In this paper the analytical solution of the dynamic response of the bridge has been determined. The solution has been obtained with a technique of closing on the order of the moments.