• ETRI Journal
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• v.42 no.3
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• pp.341-350
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• 2020

In a wireless sensor network (WSN), the data transmission technique based on the cooperative multiple-input multiple-output (CMIMO) scheme reduces the energy consumption of sensor nodes quite effectively by utilizing the space-time block coding scheme. However, in networks with high node density, the scheme is ineffective due to the high degree of correlated data. Therefore, to enhance the energy efficiency in high node density WSNs, we implemented the distributed source coding (DSC) with the virtual multiple-input multiple-output (MIMO) data transmission technique in the WSNs. The DSC-MIMO first compresses redundant source data using the DSC and then sends it to a virtual MIMO link. The results reveal that, in the DSC-MIMO scheme, energy consumption is lower than that in the CMIMO technique; it is also lower in the DSC single-input single-output (SISO) scheme, compared to that in the SISO technique at various code rates, compression rates, and training overhead factors. The results also indicate that the energy consumption per bit is directly proportional to the velocity and training overhead factor in all the energy saving schemes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.310-315
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• 1998

This study includes noise automatic inspection system for washing machine auto-transmission one of modern home necessary. We effort to find and certificate sound noisesource by sound power and sound intensity, and apply to frequency analysis in vibration related sound noise. Still more we have been studying to data acquisition and programming for MS VisualBasic version 5.0. System component is below. 1) Pentium PC for data acquisition. 2) DSO for noise acquisition. 3) S/W for comparison and decision. 4) I/F Board for data communication. Wave form data through the DSO are converting to ASCII code data. The ASCII code through binary converting S/W are to be decision fitness or the badness comparison S/W. Finally, we will making noise monitoring system and automatic inspection system.

• Journal of Information Processing Systems
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• v.16 no.5
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• pp.1048-1063
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• 2020

In this study, we propose a reinforcement learning agent to control the data transmission rates of nodes in carrier sensing multiple access with collision avoidance (CSMA/CA)-based wireless networks. We design a reinforcement learning (RL) agent, based on Q-learning. The agent learns the environment using the timeout events of packets, which are locally available in data sending nodes. The agent selects actions to control the data transmission rates of nodes that adjust the modulation and coding scheme (MCS) levels of the data packets to utilize the available bandwidth in dynamically changing channel conditions effectively. We use the ns3-gym framework to simulate RL and investigate the effects of the parameters of Q-learning on the performance of the RL agent. The simulation results indicate that the proposed RL agent adequately adjusts the MCS levels according to the changes in the network, and achieves a high throughput comparable to those of the existing data transmission rate adaptation schemes such as Minstrel.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.336-339
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• 2001

Transmission line data are very important for studying loadflow. Short circuit data(positive sequence, zero sequence) of 345kV and 154kV line were calulated and compared with KEPCO's line characteristics data. This Paper presents method of verification and complement of line data in PSS/E loadflow data using TMLC (Transmission Line Characteritics) program.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1340-1347
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• 2000

The international mobile telecommunication-2000(IMT-2000) system can support not only the non-realtime multimedia traffic such as data such as data image but also the realtime multimedia traffic such as voice, video. In the paper we propose multicode allocation and handoff schemes for efficient transmission of realtime and non-realtime data in cdma2000. In those schemes the bandwidth of target cell is reserved based on moving direction of mobiles to support QoS of realtime multimedia data and the reserved bandwidths is used by the non-realtime mobiles of the target cell until the mobiles want to perform hadoff. Our framework is able to guarantee QoS continuity of realtime multimedia data and carries the maximum number of subscriber. System performance is evaluated and compared with conventional scheme considering transmission delay channel utilization and blocking probability by computer simulation.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.11-14
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• 2010

In this paper, an improved binary-CDMA (Code Division Multiple Access) system for high speed multimedia data transmission will be presented. The improved binary CDMA technology will be used in municipal wireless network. The new name of the system is the Guardian system using a binary CDMA technology. The Guardian system can provide high data rate, and improve its throughput by minimizing latency from the limitation of resources of system bus during multimedia data transmission. Finally, we analyze the performance of Guardian modem according to the report of wireless data transmission test.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.108-112
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• 2021

For smart mobile devices, the wireless communication module is one of the hardware modules that consume the most energy. If we can build a multi-channel multi-interface environment using heterogeneous communication modules and operate them dynamically, data transmission performance can be highly improved by increasing the parallelism. Also, because these heterogeneous modules have different data rates, transmission ranges, and power consumption, we can save energy by exploiting a power efficient and low speed wireless interface module to transmit/receive sporadic small data. In this paper, we propose a power efficient data transmission method using heterogeneous communication networks. We also compared the performance of our proposed scheme to a conventional scheme, and proved that our proposed scheme can save energy while guaranteeing reasonable data delivery time.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.8
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• pp.703-709
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• 2010

An analysis tool for predicting transmission loss in high speed trains based on combined use of the statistical energy analysis and the finite element methods has been proposed. The analysis utilizes a commercially available numerical solver VA ONE with imbedded NASTRAN module. The proposed analysis tool is first verified by comparing numerically predicted transmission loss of a light rail transport(LRT) structure with experimental results. The comparison shows that the numerically predicted transmission loss is similar to the experimental data. The analysis tool is then applied to the prediction of transmission loss in the high speed train(HST) currently under development. Various sub-structures such as the floor, side panel and ceiling have been numerically analyzed to predict their transmission losses. The results obtained here can be used as input data for predicting the interior noise level of the HST at design stage.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.3
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• pp.116-122
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• 2006

The underground transmission lines is continuously expanded in power systems. Therefore the fault of underground transmission lines are increased every year because of the complication of systems. However the studies dealing with fault location in the case of the underground transmission lines are rarely reported except for few papers using traveling wave method and calculating underground cable impedance. This paper describes the algorithm using fuzzy system and travelling wave method in the underground transmission line. Fuzzy inference is used for fault discrimination. To organize fuzzy algorithm, it is important to select target data reflecting various underground transmission line transient states. These data are made of voltage and average of RMS value on zero sequence current within one cycle after fault occurrence. Travelling wave based on wavelet transform is used for fault location. In this paper, a variety of underground transmission line transient states are simulated by EMTP/ATPDraw and Matlab. The input which is used to fault location algorithm are Detail 1(D1) coefficients of differential current. D1 coefficients are obtained by wavelet transform. As a result of applying the fuzzy inference and travelling wave based on wavelet transform, fault discrimination is correctly distinguished within 1/2 cycle after fault occurrence and fault location is comparatively correct.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.386-398
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• 2019

The transmission capacity of transmission lines is affected by environmental parameters such as ambient temperature, wind speed, wind direction and so on. The environmental parameters can be measured by the installed measuring devices. However, it is impossible to install the environmental measuring devices throughout the line, especially considering economic cost of power grid. Taking into account the limited number of measuring devices and the distribution characteristics of environment parameters and transmission lines, this paper first studies the environmental parameter estimating method of inverse distance weighted interpolation and ordinary Kriging interpolation. Dynamic thermal rating of transmission lines based on IEEE standard and CIGRE standard thermal equivalent equation is researched and the key parameters that affect the load capacity of overhead lines is identified. Finally, the distributed thermal rating of transmission line is realized by using the data obtained from China meteorological data network. The cost of the environmental measurement device is reduced, and the accuracy of dynamic rating is improved.