• Explosives and Blasting
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• v.35 no.4
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• pp.27-35
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• 2017

A total of 22 sites around openings of limestone mine are chosen to assess rock mass classification schemes such as RMR, Q-system, and GSI. RMR and Q are modified to estimate the relationship with GSI. Q' is the modified Q with SRF=1.0 and $J_w=1.0$. Rock mass is assumed to be completely dry and very favorable discontinuity orientations are assumed to estimate ${RMR_{89}}^{\prime}$. Relationships of Q-Basic RMR, Q-Total RMR, ${GSI-RMR_{89}}^{\prime}$, and GSI-Q' are analyzed, in which a correlation of ${GSI-RMR_{89}}^{\prime}$ is found to be the highest. Failure strains are calculated using the modulus ratios and most measuring sites appear to be stable with low failure strain class.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.810-819
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• 2007

The I/Q unbalance which is generated by non-ideal components such as a $90^{\circ}$ phase shifter and I/Q filters is an inevitable physical phenomenon and leads to performance degradation when we implement a coherent two-dimensional (2-D) modulation/demodulation system. This paper provides an exact and general expression for the SEP(symbol error probability) of DVB-S2 system with I/Q phase and amplitude unbalance over AWGN channel. Coordinate rotation and shift techniques used to redefine a received signal are key mathematical tools. In conclusion, the derived result is expressed as a linear combination of the 2-D Gaussian Q-functions.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.737-744
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• 2000

This paper resorts to rock mass rating and rock mass quality to draw value based on the evaluation of rock and to draw interrelation formula in relation to rock mass quality, A comparative analysis was given of survey values reported in the existing documents. This paper has tried to find out the relationship between RMR and Q System for the sake of choosing rational reinforcing patterns and of the safety of tunnels. The results run as follow: RMR=8.251n(Q)+43.83. This paper has also tried to find out the relationship between RMR and Q System by using Fuzzy Approximate Reasoning Concept. We suggest that those in charge should not depend on a single system only after evaluating the classification of rocks, and compare one result with another for the good of keeping track of the condition of base rocks in a better way.

• Journal of Korea Multimedia Society
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• v.11 no.3
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• pp.353-363
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• 2008

A multi-agent system has a longer learning period and larger state-spaces than a sin91e agent system. In this paper, we suggest a new method to reduce the learning time of Nash Q-learning in a multi-agent environment. We apply Macro-actions to Nash Q-learning to improve the teaming speed. In the Nash Q-teaming scheme, when agents select actions, rewards are accumulated like Macro-actions. In the experiments, we compare Nash Q-learning using Macro-actions with general Nash Q-learning. First, we observed how many times the agents achieve their goals. The results of this experiment show that agents using Nash Q-learning and 4 Macro-actions have 9.46% better performance than Nash Q-learning using only 4 primitive actions. Second, when agents use Macro-actions, Q-values are accumulated 2.6 times more. Finally, agents using Macro-actions select less actions about 44%. As a result, agents select fewer actions and Macro-actions improve the Q-value's update. It the agents' learning speeds improve.

• Tunnel and Underground Space
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• v.29 no.5
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• pp.305-317
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• 2019

The RMR and Q-system for characterizing rock mass and drilling core, and for estimating the support and reinforcement measures in mine galleries, tunnels and caverns have been widely used by engineers. SMR has been widely used in the rock mass classification for rock slope, but Q-Slope has been introduced into slopes since 2015. In the last ten years, a modified Q-system called Q-slope has been tested by the many authors for application to the benches in open pit mines and excavated road rock slopes. The results have shown that a simple correlation exists between Q-slope values and the long-term stable and unsupported slope angles. Just as RMR and Q have been used together in a tunnel or underground space and complemented by comparison, Q-Slope can be used in parallel with SMR. This paper introduces how to use Q-Slope which has not been announced in Korea and application examples of Pasir open pit coal mine in Indonesia.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.368-375
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• 2000

For safety reason ATS(Automatic Train Stop) system is being used, which is a kind of communication system with a feedback amplifier and a transformer on the train and wayside coils. The coils are highly resonant LC circuits, also have very high Q(Quality) factors. The Q factors of wayside ATS coils are to be maintained high enough for the amplifier to operate reliably. In this paper a novel Q measurement system is proposed. The system measures the resonant frequency and the bandwidth of the ATS coils, by controlling the phase difference between the transformer and the coil using digital PLL(Phase Locked Loop). The overall configuration and algorithms of the proposed system and the digital PLL control schemes are presented in details. The experimental waveforms are shown to verify the system performances.

• Journal of the Korean Mathematical Society
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• v.52 no.2
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• pp.239-268
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• 2015

Let Q be a finite quiver and $G{\subseteq}Aut(\mathbb{k}Q)$ a finite abelian group. Assume that $\hat{Q}$ and ${\Gamma}$ are the generalized Mckay quiver and the valued graph corresponding to (Q, G) respectively. In this paper we discuss the relationship between indecomposable $\hat{Q}$-representations and the root system of Kac-Moody algebra $g({\Gamma})$. Moreover, we may lift G to $\bar{G}{\subseteq}Aut(g(\hat{Q}))$ such that $g({\Gamma})$ embeds into the fixed point algebra $g(\hat{Q})^{\bar{G}}$ and $g(\hat{Q})^{\bar{G}}$ as a $g({\Gamma})$-module is integrable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1A
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• pp.37-45
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• 2005

In this paper, after analyzing the effect of I/Q imbalance in an OFDM system, the detection method of an OFDM signal distorted by I/Q imbalance is proposed. Also, the channel estimation and the pilot symbol design scheme are proposed for using the proposed detection method. Since I/Q imbalance in an OFDM system degrades the SIR and the BER(Bit Error Ratio) performance, the robust detection method is required for an OFDM system. the proposed detection method can effectively suppress the interference caused by I/Q imbalance using characteristics of an OFDM signal differently from the conventional method, and results in improving the SIR of a desired OFDM signal.

• Journal of Korean Society for Quality Management
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• v.44 no.3
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• pp.541-552
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• 2016

Purpose: In this study, we propose that how to approach a effective system engineering and optimize system engineering management process for the mass production weapon system parts localization development process and success in DTaQ. Methods: To approach a effective system engineering for the mass production weapon system parts localization, we analyze a weapon system acquisition process and system engineering process of Republic of Korea and DTaQ parts localization business regulations in advance. after results of analysis of them, we implement a optimized parts localization development system engineering based on ISO/IEC/IEEE 15288. Results: In order to apply International Standard ISO/IEC/IEEE 15288 to the mass production weapon system parts localization development process, we compare the mass production weapon system parts localization acquisition environment with ISO/IEC/IEEE 15288 and analyze them. therefore, It is possible to implement a part of concept stage and development stage of ISO/IEC/IEEE total life cycle stage for the mass production weapon system parts localization development process. To achieve the technical review milestones of DTaQ parts localization business regulations in the selected stages of ISO/IEC/IEEE, the development and management agency perform 2 high rank process and 19 low rank process specified in ISO/IEC/IEEE. Conclusion: When the development and management agency perform the mass production weapon system parts localization development using the proposed system engineering approach, they should easily meet milestone through the clarified requirement and simplified System Engineering output documents in limited development period.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1939_1941
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• 2009

The modulation quality of the RF transmitter in a wireless communication system usually affects system performance and it mostly depends on both a nonlinearity and a distortion, from the intermodulation products and the I/Q mismatch such as I/Q amplitude error and a local phase error, respectively. This paper focused on how much the error vector magnitude(EVM) which describes the modulation accuracy changes according to the variation of the I/Q mismatch components at I/Q modulator. For this work, the equation for the EVM including the I/Q mismatch components can be induced and calculated in accordance with the variation of the I/Q mismatch components. Consequently, the effect of I/Q mismatch components on the EVM, which is required in the transmitter specification of Personal Area Network, can be clearly analyzed.