• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1605-1614
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• 2013

This paper presents a probabilistic methodology for small signal stability analysis of power system with correlated wind sources. The approach considers not only the stochastic characteristics of wind speeds which are treated as random variables with Weibull distributions, while also the wind speed spatial correlations which are characterized by a correlation matrix. The approach based on the 2m+1 point estimate method and Cornish Fisher expansion, the orthogonal transformation technique is used to deal with the correlation of wind farms. A case study is carried out on IEEE New England system and the probabilistic indexes for eigenvalue analysis are computed from the statistical processing of the obtained results. The accuracy and efficiency of the proposed method are confirmed by comparing with the results of Monte Carlo simulation. The numerical results indicate that the proposed method can actually capture the probabilistic characteristics of mode properties of the power systems with correlated wind sources and the consideration of spatial correlation has influence on the probability of system small signal stability.

• Steel and Composite Structures
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• v.36 no.2
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• pp.197-211
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• 2020

Application of the steel ring as a type of seismic fuse has been one of the efforts made by researchers in recent years aiming to enhance the ductility of the bracing systems which in turn, possesses various advantages and disadvantages. Accordingly, to alleviate these disadvantages, an innovative bracing system with a diamond scheme equipped with a steel ring is introduced in this paper. In this system, the braces and yielding circular damper act in parallel whose main functionality is to increase ductility, energy absorption and mitigate drawbacks of the existing bracing systems, in which the braces and yielding circular damper act in parallel. To conduct the experimental tests, specimens with three types of rigid, semi-rigid and pinned connections were built and subjected to cyclic loading so that their performance could be analyzed. Promisingly, the results indicate both great applicability and efficiency of the proposed system in energy absorption and ductility. Moreover, it was concluded that as the braces and damper are in parallel, the use of a steel ring with smaller size and thickness would result in higher energy absorption and load-resisting capacity when compared to the other existing systems. Finally, to assess the potential of numerically modeling the proposed system, its finite element model was simulated by ABAQUS software and observed that there is a great agreement between the numerical and experimental results.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.71-77
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• 2012

This study examines the factors influencing internet protocol television (IPTV) usage intention. Using Davis's technology acceptance model (TAM) and DeLone and McLean's model of information system success, this study investigates the effects of information system quality (information quality, system quality, and service quality) and media quality on IPTV use in terms of perceived usefulness, perceived ease of use, and usage intention. We examined the proposed model by employing structural equation modeling and survey data from 222 IPTV users. The results indicate that information quality, service quality, and media quality had significant effects on perceived usefulness and that information quality and media quality had significant effects on perceived ease of use. However, system quality had no effect on perceived usefulness or perceived ease of use. In addition, perceived ease of use influenced perceived usefulness, and perceived usefulness and perceived ease of use influenced IPTV usage intention. Further, the stability and reliability of IPTV services encouraged IPTV use, and successful IPTV services showed high media quality.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.877-887
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• 2015

Rapid development of cities with constant increasing load and deregulation in electricity market had forced the transmission lines to operate near their threshold capacity and can easily lead to voltage instability and caused system breakdown. To prevent such catastrophe from happening, accurate readings of voltage stability condition is required so that preventive equipment and operators can execute security procedures to restore system condition to normal. This paper introduced Enhanced Hybrid Particle Swarm Optimization algorithm to estimate the voltage stability condition which utilized Fast Voltage Stability Index (FVSI) to indicate how far or close is the power system network to the collapse point when the reactive load in the system increases because reactive load gives the highest impact to the stability of the system as it varies. Particle Swarm Optimization (PSO) had been combined with the ANN to form the Enhanced Hybrid PSO-ANN (EHPSO-ANN) algorithm that worked accurately as a prediction algorithm. The proposed algorithm reduced serious local minima convergence of ANN but also maintaining the fast convergence speed of PSO. The results show that the hybrid algorithm has greater prediction accuracy than those comparing algorithms. High generalization ability was found in the proposed algorithm.

• Journal of Computing Science and Engineering
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• v.2 no.4
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• pp.394-411
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• 2008

The data in automation and control systems can be achieved not only from different field devices but also from different OPC (OLE for Process Control) servers. However, current OPC clients can only read and decode the simple data from OPC servers. They will have some problems to acquire structured data and exchange the structured data. In addition to the large network control systems, the OPC clients can read, write, and subscribe to thousands of data points from/to OPC servers. Due to that, the most important factor for building a high performance and scalable industrial control system is the ability to transfer the process data between server and client in the most efficient and fastest way. In order to solve these problems, we propose a means to implement the OPC DA (Data Access) server supporting the OPC complex data, so that the OPC DA clients are able to read and decode any type of data from OPC servers. We also propose a method for caching the process data in large industrial control systems to overcome the limitation of performance of the pure OPC DA system. The performance analysis and discussion indicate that the proposed system has an acceptable performance and is feasible in order for applying to real-time industrial systems today.

• Journal of the Korean Society of Costume
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• v.54 no.6
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• pp.77-90
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• 2004

The purpose of this study was to provide basic information requisite in the new sizing system for gloves. KS glove standards' size dimensions, size designation and labeling systems were analyzed. Also, KS glove standards' control sizes were compared to the anthropometric data of 824 Korean adults taken in the previous study. As well, the ISO hand size system was also compared to the anthropometric data of the previous study according to frequency tables of hand length and hand circumference. The size dimensions showed differences among KS standards and there was no size designation and labeling systems existed in KS standards. Among KS glove size systems, protective rubber gloves for radioactive contamination and surgical rubber gloves' size which followed ISO system were accurately indicate the hand size of the person a glove is intended to fit. ISO glove sizing system comprised the control dimensions of hand length and hand circumference. The coverage of ISO size A was 84.8% which was highest among ISO size A. B, C. And in hand circumference 178, 191, 203, 216mm showed the frequencies above 3% and in hand length 167, 175. 183, 191, 199mm showed the frequencies above 3%.

• Advances in Traditional Medicine
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• v.7 no.5
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• pp.518-526
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• 2008

Recently a major goal in asthma therapy is to reduce or prevent the inflammatory response of airway. Eosinophilic accumulation in the tissue is a prominent feature of allergic diseases including asthma. Production of chemokines by bronchial epithelial cells may contribute to the allergic inflammation by recruiting eosinophils. In this study we evaluated the inhibitory effect of Gamichungsangbohatang (GMCSBHT), used traditionally in treating asthma, on secretion of chemokines for eosinophils in human A549 epithelial cells. Chemokines such as eotaxin, RANTES, IL-8 were inhibited in a dose-dependent manner, but IL-16 showed no inhibition by GMCSBHT. These findings indicate that GMCSBHT might be a therapeutic value in treating asthma by suppression of chemokines secretion associated with local accumulation of eosinophils.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3054-3067
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• 2015

The phenomena of higher channel cross polarization discrimination (XPD) is mainly observed for future wireless technologies such as small cell network and massive multiple-input multiple-output (MIMO) system. Therefore, utilization of high XPD is very important and space-polarization division multiple access (SPDMA) with dual-polarized MIMO system could be a suitable solution to high-speed transmission in high XPD environment as well as reduction of array size at base station (BS). By SPDMA with dual-polarized MIMO system, two parallel data signals can be transmitted by both vertically and horizontally polarized antennas to serve different mobile stations (MSs) simultaneously compare to conventional space division multiple access (SDMA) with single-polarized MIMO system. This paper analyzes the performance of SPDMA for maximum ratio transmission (MRT) in time division duplexing (TDD) system by proposed dual-polarized MIMO spatial channel model (SCM) compare to conventional SDMA. Simulation results indicate that how SPDMA utilizes the high XPD as the number of MS increases and SPDMA performs very close to conventional SDMA for same number of antenna elements but half size of the array at BS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1630-1642
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• 2016

Inter-domain routing is the most critical function of the Internet. The routing system is a logical network relying on the physical infrastructure with geographical characteristics. Nature disasters or disruptive accidents such as earthquakes, cable cuts and power outages could cause regional failures which fail down geographically co-located network nodes and links, therefore, affect the resilience of inter-domain routing system. This paper presents a model for regional failures in inter-domain routing system called REFER for the first time. Based on REFER, the resilience of the inter-domain routing system could be evaluated on a finer level of the Internet, considering different routing policies of intra-domain and inter-domain routing systems. Under this model, we perform simulations on an empirical topology of the Internet with geographical characteristics to simulate a regional failure locating at a city with important IXP (Internet eXchange Point). Results indicate that the Internet is robust under a city-level regional failure. The reachability is almost the same after the failure, and the reroutings occur at the edge of the Internet, hardly affecting the core of inter-domain routing system.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.753-759
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• 1995

One of the important features of the advanced nuclear power plants is the system simplification. In this work, a model has been introduced to quantitatively evaluate the system simplification. A few models have been developed for quantitative evaluation of design simplification and the design enhancements of CVCS of the advanced reactors have been evaluated with models based on the entropy concept and the system availability. In addition, operational interface of CVCS with peripheral systems has been considered to develop a new evaluation model in this work. The quantification results for the design of the System 80+ and KSNPP indicate that the simplicity of the CVCS is primarily dependent on the type and number of charging pumps.