• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.543-546
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• 2005

In this paper, it was estimated the BER performance of the individual system type by applying the SFH type and the FFH type to the FH MC-DS CDMA system that combined the strong points of MC DS/CDMA and that of Frequency Hopping under the Nakagami fading channel with Multi-tone Jamming. An increase in the number of hoppings means that it can improve the BER performance by reducing the receiving burden of the FH MC DS/CDMA by achieving a frequency diversity effect. Therefore, I verified that the performances of the FH MC DS/CDMA system could be improved by increasing the number of hoppings.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.6 s.165
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• pp.902-910
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• 2007

The purpose of this study was to suggest future marketing strategy for Korean textile and apparel industry so that they could find a way to maintain a major sourcing site in the global market place. This study identified international buyers' visiting purposes and the items they were most interested in sourcing from Korea according to their firm types and home country regions. This study analyzed the survey results obtained fiom international buyers who visited the international textile and apparel trade show in Seoul, Korea. The data was analyzed using frequency and ${\chi}^2$-test analysis. The results showed that there was a significant relationship between buyers' country regions and their interests. There was also a significant relationship between buyers' firm types and their visiting purposes. The results indicated that decision making for what Korean industry should focus their marketing efforts on should be different according to the buyers' country regions and firm types. This study was conducted to present an effective marketing strategy for how Korean textile and apparel industries could survive in the competitive global marketplace.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2843-2852
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• 2013

In the nested mobile network environment, the mobile node selects one of multiple mobile routers. The MR(Mobile Router) by existing top-down or bottom-up methods may not be the optimal MR if the numbers of mobile nodes and routers are substantially increased, and the scale of the network is increased drastically. Since an inappropriate MR decision causes handover or binding renewal to mobile nodes, determining of the optimal MR is important for efficiency. In this paper, we propose an algorithm that decides on the optimal MR using MR QoS(Quality of Service) information, and we describe how to understand the various structured MLP(Multi-Layered Perceptron) based on the algorithm. In conclusion, we prove the ability of the suggested neural network for a nesting mobile network through the performance analysis of each learned MLP.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.43-54
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• 2007

Despite the importance of customer satisfaction corresponding to the phenomenal development of the gas industries, supplier-centered management still prevails in the city gas industry due to the monopolistic market environment. However, customer's demands for diverse and higher services are ever growing in the midst of the development and the accelerated competition of the service industries. In this context, customer satisfaction management may be the best style of management for establishing a short, mid and long-term foundation of growth. This paper derives directions for improving customer satisfaction management in such 3 areas as systematic, technological and service improvement from the environmental changes as well as from the customer needs. Based on the survey and comparative analysis of customer satisfaction, we also suggest 5 growth strategies to maintain sustainable development of the gas industry in the midst of competitive environment between city gas companies and among diversified energy businesses and to protect rights of the city gas consumers.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.1
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• pp.45-52
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• 2020

Even though sewers have been conventionally designed to prevent from sediment deposition using a specified minimum velocity or shear stress at a particular depth of flow or with a particular frequency of occurrence, it was appreciated that these methods do not consider the characteristics and concentration of the sediment and the specific hydraulic conditions of the sewer with sediment. In this study, a densimetric Froude number formula was suggested considering particle diameter and volumetric concentration of the sediment as well as flow depth and flowrate, based on several domestic field inspections, which was compared with other formulas proposed by previous investigators. When the sediment concentration was not considered, the calibration coefficient of 0.125-1.5 to the densimetric Froude numbers of this study was needed to obtain the similar ones with previous investigators'. For the densimetric Froude number formula obtained with consideration of sediment concentration, the exponent value of term C_v was almost the same as that of previous results and that of d₅₀/R_h was similar for F_r < 2.2.

• Journal of Ocean Engineering and Technology
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• v.22 no.2
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• pp.65-71
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• 2008

Recently, many researches in relation to data transmission with faster speed and greater volume, many researches have been carried out on sonar systems for underwater communication. According to these researches, an acoustic transducer for underwater communication requires wide bandwidth properties. In domestic researches for underwater communication sonar, an operating frequency in the range of $20{\sim}40\;kHz$ is used. In this paper, we propose anon-resonance type acoustic transducer for underwater communication. The TVR (transmitting voltage response) characteristics increased linearly as the frequency increased, and the RVS (receiving voltage sensitivity) characteristics were constant as the frequency increased. Traditional techniques for wide bandwidth transducershave a limit and a transmission loss difference at lower and higher frequency operating ranges. In this paper, the new transducer proposed decreased the transmission loss under some conditions. It was optimized with the FE analysis tool (ATILA) and evaluated using the TVR and the RVS characteristics in the range of $10{\sim}90\;kHz$. The value of TVR was 138 dB at 20 kHz and 148 dB at 40 kHz, and the differences was 12 dB. The value of RVS was $195{\pm}2\;dB$ and nearly constant. From theseresults, it is certain that the developed transducers can be used for an underwater communication network in the 1.3 km range with both a 20 kHz bandwidth and 30 kHz center frequency.

• Journal of Magnetics
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• v.20 no.1
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• pp.40-46
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• 2015

This study investigated the accuracy of magnetic resonance angiography (MRA) and computed tomography angiography (CTA) in terms of reflecting the actual vascular length. Three-dimensional time of flight (3D TOF) MRA, 3D contrast-enhanced (CE) MRA, volume-rendering after CTA and maximum intensity projection were investigated using a flow model phantom with a diameter of 2.11 mm and area of $0.26cm^2$. 1.5 and 3.0 Tesla devices were used for 3D TOF MRA and 3D CE MRA. CTA was investigated using 16 and 64 channel CT scanners, and the images were transmitted and reconstructed by volume-rendering and maximum intensity projection, followed by conduit length measurement as described above. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s using the 3.0 Tesla apparatus, and $2.57{\pm}0.07mm$ with a velocity of 71.5 cm/s using the 1.5 Tesla apparatus; both images were magnified from the actual measurement of 2.11 mm. The measurement with the 16 channel CT scanner was smaller ($3.83{\pm}0.37mm$) than the reconstructed image on maximum intensity projection. The images from CTA from examination apparatus and reconstruction technique were all larger than the actual measurement.

• Smart Structures and Systems
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• v.19 no.1
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• pp.21-31
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• 2017

To control the stochastic vibration of a vibration-sensitive instrument supported on a beam, the beam is designed as a sandwich structure with magneto-rheological visco-elastomer (MRVE) core. The MRVE has dynamic properties such as stiffness and damping adjustable by applied magnetic fields. To achieve better vibration control effectiveness, the optimal bounded parametric control for the MRVE sandwich beam with supported mass under stochastic and deterministic support motion excitations is proposed, and the stochastic and shock vibration suppression capability of the optimally controlled beam with multi-mode coupling is studied. The dynamic behavior of MRVE core is described by the visco-elastic Kelvin-Voigt model with a controllable parameter dependent on applied magnetic fields, and the parameter is considered as an active bounded control. The partial differential equations for horizontal and vertical coupling motions of the sandwich beam are obtained and converted into the multi-mode coupling vibration equations with the bounded nonlinear parametric control according to the Galerkin method. The vibration equations and corresponding performance index construct the optimal bounded parametric control problem. Then the dynamical programming equation for the control problem is derived based on the dynamical programming principle. The optimal bounded parametric control law is obtained by solving the programming equation with the bounded control constraint. The controlled vibration responses of the MRVE sandwich beam under stochastic and shock excitations are obtained by substituting the optimal bounded control into the vibration equations and solving them. The further remarkable vibration suppression capability of the optimal bounded control compared with the passive control and the influence of the control parameters on the stochastic vibration suppression effectiveness are illustrated with numerical results. The proposed optimal bounded parametric control strategy is applicable to smart visco-elastic composite structures under deterministic and stochastic excitations for improving vibration control effectiveness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.203-208
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• 2021

At the manufacturing site, workers have been operating by inputting materials into the manufacturing process and leaving input records according to the work instructions, but product LOT tracking has been not possible due to many omissions. Recently, it is being carried out as a system to automatically input materials using RFID-Tag. In particular, the initial automatic recognition rate was good at 97 percent by automatically generating input information through RACK (TAG) ID and RACK input time analysis, but the automatic recognition rate continues to decrease due to multi-material RACK, TAG loss, and new product input issues. It is expected that it will contribute to increasing speed and yield (normal product ratio) in the overall production process by improving automatic recognition rate and real-time monitoring through the establishment of artificial intelligent smart factory datasets.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.70-76
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• 2021

The relevance of intelligence involves the definition of such communication systems of PR-management and branding of media channels with the use of social networks, which are already implemented in practice by modern representatives of professional PR product. The purpose of the investigation is to determine the system of implementation of technologies of PR-management and branding of media channels with the use of social networks based on a survey of PR and brand of different media channels on the basis of a survey of brand managers and PR. 980 respondents from Ukraine took part in the survey. The survey was conducted on the Google-forms platform. The results outline a list of the most popular social networks and messengers for the implementation of PR management and branding technologies, including Facebook, Twitter, Google, LinkedIn, Tumblr; Telegram, WhatsApp, Viber, Skype. It is determined that the criteria of branding analysis are informativeness, centralization/distribution, content, feedback intensity. Identified 2 prospects for the development of branding in an interactive media environment (creation of a presentation system; integration of websites of social media and companies in universal centers). The criteria of general importance of the factors influencing the behavioral intention of consumers to use social media channels are presented (satisfaction, accessibility, perceived usefulness, trust, ease of use, attitude, social influence, self-efficacy). The meaning of the content of social media channels (public, informational and communication) is indicated. The practical significance of the study was to present the links between the criteria, development prospects and the values of branding factors.