• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4C
• /
• pp.282-294
• /
• 2002

The modern telecommunication networks are composed of various network-type and are managed by various management technologies, such as TMN, SNMP, TINA etc. Furthermore, the network user's needs of real-time multimedia services are rapidly increasing. In order to guarantee the user-requested quality-of-service(QoS) and keep the network utilization at maximum, it is required to manage the network performance continuously after the network is deployed. The performance management function should provide the useful information for the network expansion and the capacity reallocation in the future. In this paper, we propose a DPE-based performance management architecture for the integrated management of the heterogeneous network elements with TMN and SNMP. We propose an approach to provide the Intranet traffic monitoring and analysis function using layered network management concept and distributed processing technology. The proposed architecture has been designed and implemented based on multiprocess and multithread structure to support concurrent processing. To manage the traffic according to the Intranet service categories, we implemented an ITMA(Intelligent Traffic Monitoring Agent) with packet capture library. With the proposed architecture, we could measure and analyze the real Intranet traffic of Yeungnam University.

• Nuclear Engineering and Technology
• /
• v.42 no.5
• /
• pp.590-599
• /
• 2010

Recently, efficient operation and practical management of power plants have become important issues in the nuclear industry. In particular, typical aging parameters such as stress and cumulative usage factor should be determined accurately for continued operation of a nuclear power plant beyond design life. However, most of the major components have been designed via conservative codes based on a 2-D concept, which do not take into account exact boundary conditions and asymmetric geometries. The present paper aims to suggest an effective fatigue evaluation methodology that uses a prototype of the integrated model and its transfer functions. The validity of the integrated 3-D Finite Element (FE) model was proven by comparing the analysis results of individual FE models. Also, mechanical and thermal transfer functions, known as Green's functions, were developed for the integrated model with the standard step input. Finally, the stresses estimated from the transfer functions were compared with those obtained from detailed 3-D FE analyses results at critical locations of the major components. The usefulness of the proposed fatigue evaluation methodology can be maximized by combining it with an on-line monitoring system, and this combination, will enhance the continued operations of old nuclear power plants.

• Particle and aerosol research
• /
• v.7 no.1
• /
• pp.31-44
• /
• 2011

The hourly volatile organic compounds(VOCs) concentrations between 2005 and 2008 at Bulgwang photochemical assessment monitoring station were investigated to establish a method for quality assurance and quality control(QA/QC) procedure. Systematic error, erratic error, and random error, which was manifested by outlier and highly fluctuated data, were checked and removed. About 17.3% of the raw data were excluded according to the proposed QA/QC procedure. After QA/QC, relative standard deviation for representing 15 species concentrations decreased from 94.7-548.0% to 63.4-125.8%, implying the QA/QC procedure is proper. For further evaluation about the adequacy of QA/QC procedure, principal components analysis(PCA) was carried out. When the data after QA/QC procedure was used for PCA, the extracted principal components were different from the result from the raw data and could logically explain the major emission sources(gasoline vapor, vehicle exhaust, and solvent usage). The QA/QC procedure based on the concept of errors is inferred to proper to be applied on VOCs. However, an additional QA/QC step considering the relationship between species in the atmosphere needs to be further considered.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.5
• /
• pp.793-800
• /
• 2010

GPS spoofing is an intentional interference which uses the mimic GPS signals to fake the receivers. The generic GPS receiver is hard to recognize the spoofing signal because the spoofer generates the fake signals as close as possible to the GPS signal. So the spoofer can do critical damage to public operations. This paper introduces a basic concept of spoofing and analyzes the effect of the spoofing signal to the GPS receiver. Also for stand-alone GPS receivers, two anti-spoofing methods are implemented : RAIM based method and the SQM based method. To evaluate the performance of anti-spoofing method, the software based spoofing signal generator and GPS signal generator are implemented. The performance of the anti-spoofing methods obtained using the output of the software based GPS receiver shows that SQM based method is more effective when multiple spoofing signals exist.

• Tribology and Lubricants
• /
• v.25 no.1
• /
• pp.56-60
• /
• 2009

A journal bearing is used in a hydrodynamic lubrication state, but it becomes a boundary lubrication state that asperity of a contact part touch each other when pressure is too high and an enough oil film is not formed by viscosity change due to lubricating oil temperature. At this time, abrasion due to contact between a journal and a bearing is unavoidable, and scuffing damage that the journal adheres to the bearing occurs if the process is repeated. Damage of the journal bearing is an important problem because it gives huge damage to a machine and can generate large accidents such as economic loss and human life damage. In this study, method for using the pull-up resistor concept was introduced as the monitoring technology. This monitoring system is important to enhance reliability of the engine.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.6
• /
• pp.574-581
• /
• 2012

Condition-based maintenance(CBM) has been used as a useful concept for optimizing maintenance plan and decreasing maintenance cost in several kinds of plant sites. This study introduced an example that developed an integrated management system for maintenance parameters and hydraulic turbine of hydro-power plant in order to improve its maintenance strategy as applying CBM techinique. The integrated management system consists of three parts. One is a hardware part including PDA inspection system and several kind of precision measuring instruments. Another is a vibration monitoring system on hydraulic turbine. The other is a software part that takes charge of making hierarchy tree of maintenance parameters and their inspection route, managing accumulated database, assessing health condition of components, and supporting interface with other enterprise management system. The system has been installed at Chuncheon hydro-power plant for test and demonstration. It is expected that the system can contribute database construction for diagnostics and prognostics on facility health condition and systematic accumulation of know-how on operation and maintenance of plant.

• Smart Structures and Systems
• /
• v.25 no.3
• /
• pp.265-277
• /
• 2020

Recently, the concept of "drive-by" bridge monitoring system using indirect measurements from a passing vehicle to extract key parameters of a bridge has been rapidly developed. As one of the most key parameters of a bridge, the natural frequency has been successfully extracted theoretically and in practice using indirect measurements. The frequency of bridge is generally calculated applying Fast Fourier Transform (FFT) directly. However, it has been demonstrated that with the increase in vehicle velocity, the estimated frequency resolution of FFT will be very low causing a great extracted error. Moreover, because of the low frequency resolution, it is hard to detect the frequency drop caused by any damages or degradation of the bridge structural integrity. This paper will introduce a new technique of bridge frequency extraction based on Hilbert Transform (HT) that is not restricted to frequency resolution and can, therefore, improve identification accuracy. In this paper, deriving from the vehicle response, the closed-form solution associated with bridge frequency removing the effect of vehicle velocity is discussed in the analytical study. Then a numerical Vehicle-Bridge Interaction (VBI) model with a quarter car model is adopted to demonstrate the proposed approach. Finally, factors that affect the proposed approach are studied, including vehicle velocity, signal noise, and road roughness profile.

• Journal of Korean Neurosurgical Society
• /
• v.62 no.3
• /
• pp.296-301
• /
• 2019

An epileptic seizure is defined as the transient occurrence of signs and/or symptoms due to abnormally excessive or synchronous neuronal activity in the brain. The type of seizure is defined by the mode of onset and termination, clinical manifestation, and by the abnormal enhanced synchrony. If seizures recur, that state is defined as epilepsy. Antiepileptic drugs (AEDs) are the mainstay of treatment. Knowledge about initiating and maintaining adequate AEDs is beneficial for the clinician who treats children with epilepsy. This article will delineate the general principles for selecting, introducing, and discontinuing AEDs and outline guidelines for monitoring adverse effects. In general, AED therapy following a first unprovoked seizure in children is not recommended. However, treatment should be considered after a second seizure. In children and adolescents, if they are seizure-free for at least 2 years, attempts to withdraw medication/s should be made, taking into account the risks vs. benefits for the individual patient. The decision on when and what AED to use should be tailored according to the patient. For optimal treatment, the selection of adequate AEDs can be achieved by considering the precise definition of the patient's seizure and epilepsy syndrome. Continuous monitoring of both therapeutic and adverse effects is critical for successful treatment with AEDs.

• Electronics and Telecommunications Trends
• /
• v.37 no.2
• /
• pp.30-41
• /
• 2022

As the society is superaging, the number of patients with movement disabilities due to musculoskeletal or nervous system illness is rapidly increasing. To improve public health and reduce medical expenses, it is essential to develop rehabilitation systems that allow patients to resume their daily-life activities. However, the existing musculoskeletal illness diagnosis and rehabilitation method is limited in terms of precision and efficiency because it is based on an empirical diagnosis and prescription without regard for individual characteristics. To overcome these limits, it is critical to design a novel concept of routine rehabilitation therapy device that is capable of inducing musculoskeletal balance by the precise analysis of musculoskeletal usage patterns via the motion and the muscle activity tracking of linked muscles. This study introduces the trend of on-skin sensor device technology for routine musculoskeletal monitoring and therapy. For on-skin rehabilitation systems, skin-adhesive and stretchable motion/posture, electromyography, pressure sensors, small-size and low-power wireless sensor interfaces, and user-friendly rehabilitation contents based on new algorithms are combined.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.10
• /
• pp.3275-3298
• /
• 2022

Cloud-based architectures for precision agriculture are domain-specific controlled and require remote access to process and analyze the collected data over third-party cloud computing platforms. Due to the dynamic changes in agricultural parameters and restrictions in terms of accessing cloud platforms, developing a locally controlled and real-time configured architecture is crucial for efficient water irrigation and farmers management in agricultural fields. Thus, we present a new implementation of an independent sensor-enabled architecture using variety of wireless-based sensors to capture soil moisture level, amount of supplied water, and compute the reference evapotranspiration (ETo). Both parameters of soil moisture content and ETo values was then used to manage the amount of irrigated water in a small-scale agriculture field for 356 days. We collected around 34,200 experimental data samples to evaluate the performance of the architecture under different agriculture parameters and conditions, which have significant influence on realizing real-time monitoring of agricultural fields. In a proof of concept, we provide empirical results that show that our architecture performs favorably against the cloud-based architecture, as evaluated on collected experimental data through different statistical performance models. Experimental results demonstrate that the architecture has potential practical application in a many of farming activities, including water irrigation management and agricultural condition control.