• International journal of advanced smart convergence
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• v.11 no.1
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• pp.36-41
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• 2022

Recently, to improve the performance of the strongest channel gain user in non-orthogonal multiple access (NOMA) with a non-uniform source and symmetric superposition coding (SSC), a novel bit-to-symbol (BTS) mapping have been proposed. However, only the performance of the user with the stronger channel gain was analyzed. Thus, we compare the bit-error rate (BER) of the new BTS scheme with that of uniform sources, especially for the user with weakest channel gain. First, we show that the performance of the novel BTS scheme for the user with weakest channel gain also improves, compared to that of the uniform sources. Furthermore, the signal-to-noise (SNR) gain of the new BTS scheme over the uniform sourcesis calculated. As a consequence, the novel BTS scheme would improve the performance of the user with weakest channel gain as well as that with the stronger channel gain for SSC NOMA with a non-uniform source.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.143-148
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• 2006

The goal of this paper is to analyze, through simulations and experiments, GNSS interference mitigation performance under various types of antenna structures against wideband and narrowband interferences using spatial-temporal adaptive signal processing (STAP) techniques. The STAP approach, which combines spatial and temporal processing, is a viable means of GNSS array signal processing that enhancing the desired signal quality and providing protection against interference. In this paper, we consider four types of 3D antenna array structure - Uniform Linear Array (ULA), Uniform Rectangular Array (URA), Uniform Circular Array (UCA), and the Single-Ring Cylindrical Array (SRCA) under an interference environment. Analytical evaluation and simulations are performed to investigate the system performance. This is followed by simulation GPS orbits in interfered environment are used to evaluate the STAP performance. Furthermore, experiments using a 2x2 URA hardware simulator data show that with the removal of wideband and narrowband interference through the STAP techniques, the signal tracking performance can be enhanced.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.48-54
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• 2021

In most existing researches on non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC), uniform sources have been usually considered. For the first part in this two-part paper, for the strongest channel gain user, we showed that the bit-error rate (BER) for the optimal maximum a-posteriori (MAP) receiver for the non-uniform source improves slightly, compared to that of the conventional receiver for the uniform sources. We demonstrate that in communication scenarios of the non-uniform source NOMA schemes, for the weakest channel gain user, the BER performance of the optimal MAP receiver for a non-uniform source improves greatly, compared to that of the conventional receiver for uniform sources. We first derive an analytical expression of the BER for non-uniform source NOMA with SSC. Then, simulations demonstrate that the BER of the optimal MAP receiver for the non-uniform source improves, compared with that of the conventional maximum likelihood (ML) receiver for the uniform sources. In result, the proposed optimal MAP receiver for the non-uniform source could be a promising scheme for SSC NOMA, with improved BER performances.

• Journal of the Korean Society of Costume
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• v.64 no.6
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• pp.148-160
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• 2014

This study proposed the design development of performance uniform for Korean classical music. To do this, we considered the state of the performance uniform of the Korean Classical Music Band through photographic data. The research targeted the performers in Korean Classical Music Band, and conducted a survey for the preference of type, pattern, decoration, color and fabric materials. Based on the results, we extracted the design of performance uniform, which is suitable for the environment of Korean classical music performance and meets the substantial requirements of performers. The performance uniform that the current national or public Korean classical music bands are using, has two types: Western clothing and Hanbok. The attire is influenced by the genre of the music that they are playing because one of its main functions is to deliver the music to audience effectively. In addition, there are some differences in the uniform based on the gender, but no division in the design of clothing according to music instruments. However, the result of the survey show that there was no difference in preference by gender, but there was some difference according to the division of music instruments. On this study, we reflected this result in the design, and proposed the design of an convenient outer garment for everyone to wear in the music performance band.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.64-69
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• 2005

In this paper, we analyzed the nonlinear performance on the DS/CDMA Communication System. At the $BER=10^{-4}$, uniform chip waveforms have similar performance in the linear channel. However, non-uniform chip waveforms have about more 0.5[dB] power gain than the conventional raised-cosine chip waveforms. In the nonlinear HPA, non-uniform chip waveforms have worse BER performance than the uniform chip waveforms because of the high PAPR. In other words, non-uniform chip waveforms show similar performance as uniform chip waveforms if IBO (input back on) of 15[dB] is given.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.3
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• pp.456-464
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• 2016

A new combat uniform is improved for added combat safety with various functions such as survivability, battle conformity and a camouflage performance system. Camouflage performance is an important factor in terms of combat survivability since it makes identification difficult and provide security. The combat uniform is worn under extreme conditions (exposure to ultraviolet light, sweat and friction) and an excellent color fastness to repeated washing is required. In this study, we investigated the color management, durability and discoloration of new combat uniform fabric with a digital pattern for camouflage performance to provide preliminary color management data. We examined color differences between standard fabric and mass-produced combat uniform fabrics, color differences between each military supply contract firm and color changes in combat uniforms after 60 washing cycles. The slight color differences between standard fabric and mass-produced combat uniform fabrics were tolerable under quality criteria of Republic of Korea Ministry of National Defense. However, the differences between the military supply contract firms were recognizable to the naked eye and increased with repeated washing. Continuous research on color fastness under repeated washing and color management is required to standardize reliability from each military supply contract firm for the daytime performance of a combat uniform's camouflage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.15-21
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• 2011

Cooperative diversity system can be applied to an ad-hoc network for reduction of the power consumption, for expansion of the communication range, and for improving the system performance. In a selection relay cooperative diversity system which selects the maximal SNR(Signal-to-noise ratio) relay for transmitting the source information, the selected strong relay transmits continuously under slow fading channel, consequently it reduces the network lifetime. To overcome this defect, recently the uniform power relay selection has been studied to expand the network life time. We apply the uniform power relay selection to a DOT(Double opportunistic transmit) cooperative system that select the transmit relays, of which the SNR of the transmit relays exceed both of the source-relay and the relay-destination threshold. And the performance of the system is analytically derived. The performance comparisons are made among SC(Selection combining), MRC(Maximal ratio combining), and uniform power relay selection of the cooperative diversity system. We noticed that the performance of the uniform power relay selection is inferior to that of others. It is interpreted that the uniform transmit opportunity to the selected relays for extension of the network lifetime degrades the performance.

• Journal of Computing Science and Engineering
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• v.9 no.4
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• pp.177-189
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• 2015

High-performance processors using Non-Uniform Cache Architecture (NUCA) are increasingly used to deal with the growing wire delays in multicore/manycore processors. Due to the convergence of high-performance computing with embedded computing, NUCA caches are expected to benefit high-end embedded systems as well. However, for real-time systems that use multicore processors with NUCA caches, it is crucial to bound worst-case execution time (WCET) accurately and safely. In this paper, we developed a WCET analysis approach by considering the effect of static NUCA caches on WCET. We compared the WCET in real-time applications with different topologies of static NUCA caches. Our experimental results demonstrated that the static NUCA cache could improve the worst-case performance of realtime applications using multicore processor compared to the cache with uniform access time.

• Smart Structures and Systems
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• v.19 no.4
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• pp.351-360
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• 2017

Protection of structures against natural hazards such as earthquakes has always been a major concern. Semi-active control combines the reliability of passive control and versatility and adaptability of active control. So it has recently become a preferred control method. This paper proposes an algorithm based on Uniform Deformation Theory to mitigate vulnerable buildings using magneto-rheological (MR) damper. Due to the successful performance of fuzzy logic in control of systems and its simplicity and intrinsically robustness, it is used here to regulate MR dampers. The particle swarm optimization (PSO) algorithm is also used as an adaptive method to develop a fuzzy control algorithm that is able to create uniform inter-story drifts. Results show that the proposed algorithm exhibited a desirable performance in reducing both linear and nonlinear seismic responses of structures. Performance of the presented method is indicated in compare with passive-on and passive-off control algorithms.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.4
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• pp.193-198
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• 2014

Heat transfer performance variation of a condenser caused by non-uniform distribution of air flow was investigated using a numerical simulation method. A heat exchanger used for a outdoor unit of a commercial heat pump system and represented by a numerical model was selected. Non-uniform profile of air-velocity was constructed by measuring the air velocity at various locations of the outdoor unit. Simulation was conducted for various refrigerant circuits and air flow conditions. Simulation results show that the heat transfer capacity was reduced depending on the air-flow rate and the refrigerant circuit configuration. It is also shown that the capacity reduction rate is increased as the average air velocity decreases.