In this study, a personalized recommendation system for efficient integrated cognitive rehabilitation training based on bigdata was developed. The system consists of 5 main phases (collection, storage, processing, analyzing, visualization). First, in the pre-processing process before the collection phase, resulting scores from multiple cognitive rehabilitation contents and patients’ personal information are saved in database. In the collection/storage phases, the patient information saved in the database is saved in bigdata platform. In the processing phase, the data are processed/refined in a necessary form to be utilized in the analysis and statistical processing program, R. Lastly, in the analysis/visualization phases, personalized contents of integrated cognitive rehabilitation training are recommended to patients using the K-Means method of the unsupervised learning algorithms and spiral model through patients’ personal information, MMSE results, cognitive rehabilitation contents results based on the processed/refined data. Patients can utilize the personalized recommendation system for integrated cognitive rehabilitation training based on bigdata to implement cognitive function evaluation and personalized training at home.

In a wireless communication system, the performance is decreased by various interference and disturbance elements. In order to decrease the influence by these elements, the various schemes have been studied. In this paper, the method mitigating inter-cell interference (ICI) is proposed when a mobile user is located in the cell edge. ICI is one reason among the reasons of the performance reduction. The proposed scheme constructs the cooperative communication system and suggests the signal transmission method using pre-coding vectors. The proposed scheme can provide improved performance when the mobile user is located in the cell edge.

In order to improve the reliability of the OFDM systems, this paper proposes the variable modulation scheme based on the condition of the channel between the transmitter and the receiver. The proposed scheme uses the codebook that is stored in advance at the transmitter and the receiver. The key idea of the variable modulation scheme is to use the similarity with the condition of the channel between the adjacent subcarriers in the OFDM system. From the simulation results, the proposed scheme has about 3 dB SNR gain at the BER of \(10^{-3}\) compared to the conventional scheme.

For reliable communication, this letter proposes cooperative transmission scheme with spatial phase coding (SPC) in the edge area among base stations. The diversity method has the a difficulty in terms of the price and complexity in a base station with multiple antennas. Thus, this problem may be resolved by using the cooperative scheme among the base stations and the proposed scheme increases that uses economically resource by using less feedback bits. Especially, if the coverage of many base stations is overlapped, the performance of the proposed scheme is improved. From the simulation results, the proposed scheme has the better performance compared to the conventional scheme in heterogeneous network.

This letter proposes a cooperative communication scheme with pre-coding in order to improve a performance in a wireless communication system. In a conventional scheme, a performance of the system is degraded due to the signal attenuation by the path loss and inter-cell interference (ICI). The proposed scheme uses two relays in order to obtain a diversity gain. Additionally, the proposed scheme uses a constructive spatial phase coding (SPC) using the phase relation of the channels in order to obtain an improved diversity gain. Therefore, the proposed scheme can prevent the performance degradation caused by the path loss. When a mobile is located in the cell edge, the signal suffers from the ICI by the other signals transmitted from a neighboring base station. In the proposed scheme, the other signals broadcast from neighboring base station are destructively superimposed by using the destructive SPC scheme. And then the power of the destructively superimposed signal is reduced. Therefore, the proposed scheme can reduce the ICI effect in the cell edge. Also, the destructively superimposed signal does not cause the performance degradation of other mobiles in the neighboring cell. The simulation results show that the bit error performance of the proposed scheme is better than the conventional scheme.

In this paper, a dual-hop relay based on channel state is studied. In the conventional relay scheme, a relay uses the same modulation method without reference to channel state. But, a relay uses an adaptive modulation method with reference to channel state. If the channel state is poor, a relay eliminates latter 2 bits and uses Quadrature Phase Shift Keying (QPSK) modulation. If channel state is good, a relay modulates the received symbols with 16-QAM symbols by using 4 bits. The performance of the proposed scheme for Symbol Error Rate (SER) and throughput is analyzed. Keywords—Adaptive transmission, channel state, dual-hop, hierarchical modulation, relay.

In the wireless communication system, the mobile station (MS) has a performance degradation by path loss and inter-cell interference (ICI) according to the MS’s movement. Especially, the MS suffers from ICI by the unwanted signal of neighboring cell. This letter proposes adaptive transmission scheme according to the MS’s movement in order to prevent the degradation of performance by path loss and ICI. The proposed scheme uses a cooperative communication and pre-coding scheme in order to improve the performance of the wireless communication system. When the MS is located in cell edge, the proposed scheme can reduce ICI by using coordinated multi-point (CoMP) and pre-coding. The proposed scheme can reduce a power of the unwanted signal by using the destructive pre-coding. Also, the destructive pre-coding does not cause the performance degradation of the MSs in the neighboring cell. The simulation results show that the proposed scheme can improve more a performance than the conventional scheme in the wireless communication system. Key-Words: cell edge, CoMP, cooperative transmission, SPC

Recently, the wireless communication requires robust and spectrally efficient communication techniques for fading channel. Thus, for reliable communication, this paper proposes the enhanced adaptive modulation coding in the cooperative communication. The proposed scheme uses modulation coding according to the channel state. When the channel can be estimated and this estimate sent back to the transmitter, the transmission scheme can be adapted relative to the channel characteristics. The relay between source and destination uses precoding vector for efficient detection that the receiver recovers the received signal. The simulation results show enhanced performance compared with the conventional cooperative and adaptive modulation coding communication. Key-Words: AMC, cooperative communication, pre-coding

Rapid-hardening track technology for the high-speed railway gravel track has been developed to effectively improve a chronic maintenance of the high-speed railway gravel track. The roadbed is a necessary part for the rapid-hardening track technology and it is highlighted to recycle current ballast gravel on the high-speed railway, for smoothly supporting gravel to the roadbed, after cleaning. For this reason, the blasting-based waterless cleaning method is widely researched which has low cost, high performance of clearing and no environmental waste. In this paper, we describe the development of waterless ballast gravel cleaning progress and machine for recycling ballast gravel on a high-speed railway.

In the cooperative transmission scheme, both the cellular system and broadcasting system are composed. Two cellular base stations (CBSs) communicating with a user in the cell edge use cooperative transmission scheme in the conventional scheme. In the case that the distance between two CBSs and the user is distant, the conventional scheme does not guarantee the quality of the communication because the channel condition is bad. Therefore, if the distance between CBSs and a user is distant, the performance of the conventional scheme is decreased. Also, the bad channel condition has bad effects on the performance. The proposed scheme uses two relays to communicate well with CBSs when the channel condition between CBSs and the user is poor. Using the relay in the high attenuation environment can obtain both advantages of the high bit error rate (BER) and throughput performance. Keywords—Cooperative communications, diversity gain, OFDM, interworking system.

Because current wireless communication requires high reliability in a limited bandwidth environment, this paper proposes the variable modulation scheme based on the codebook. The variable modulation scheme adjusts transmission power using the codebook in accordance with channel state. Also, if the codebook is composed of many bits, the reliability is more improved by the proposed scheme. The simulation results show that the performance of proposed scheme has better reliability than the the performance of conventional scheme. Keywords—MIMO-OFDM, variable modulation, codebook, channel state.

: The conventional Wi-Fi back scatter system can only process one-to-one communication between the Wi-Fi reader and the Wi-Fi tag. For improvement of throughput of the conventional system, this paper proposes the multi-to-multi communication system. In the proposed system, the interference by the multi-to-multi communication is effectively cancelled by the orthogonal multiple access based on the identification code of the tag. Although the overhead is generated by the procedure for the multi-to-multi communication, because the procedure is processed by the Wi-Fi protocol, the overhead is insignificant for the entire communication procedure. From the numerical results, it is confirmed that the proposed system has nearly proportional increased throughput in according to the number of the tag that simultaneously participates in communication.

The retention mechanism of Ni(Ⅱ)-α-isonitroso-β-diketone imine chelates in reversed-phase HPLC has been studied by examining the effect of temperature, mobile phase composition in acetonitrile-water mixture, and molecular structure on retention. The empirical retention equation was investigated to evaluate the properties of S (hydrophilic index). The value of the S index of the Ni(Ⅱ) chelates decrease with the increasing column temperature and a linear relationship between S and log kw' has been found. The results showed that the S index is influenced by the interaction between Ni(Ⅱ) chelates and mobile phase. Molecular properties, van der Waals molar volume, polarizability and dipole moment, of the Ni(Ⅱ) chelates were calculated by Cerius 2 program and the calculations were performed at Universal Force Field (UFF) model. The S value and log kw' increase with decreasing the dipole moment of Ni(Ⅱ) chelates.