• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.951-969
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• 2010

A Study on the Management Performance of the Distribution channel's CRM : Balanced Scorecard Approach as to CRM application field of the Distribution Company About Korea Airport Service In this paper, the performances of Distribution channel's estimation schemes for CRM system are investigated. We anticipate these moves will have a positive effect on the CRM Scorecard infra, process, elevate royalty environments. As is study of used SPSSWN 15.0 correlation analysis, regression analysis & AMOS 7.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.237-253
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• 2019

For massive multiple-input multiple-output (MIMO) circumstances with time division duplex (TDD) protocol, pilot contamination becomes one of main system performance bottlenecks. This paper proposes an uplink pilot sequence assignment to alleviate this problem for spatially correlated massive MIMO circumstances. Firstly, a single-cell TDD massive MIMO model with multiple terminals in the cell is established. Then a spatial correlation between two channel response vectors is established by the large-scale fading variables and the angle of arrival (AOA) span with an infinite number of base station (BS) antennas. With this spatially correlated channel model, the expression for the achievable system capacity is derived. To optimize the achievable system capacity, a problem regarding uplink pilot assignment is proposed. In view of the exponential complexity of the exhaustive search approach, a pilot assignment algorithm corresponding to the distinct channel AOA intervals is proposed to approach the optimization solution. In addition, simulation results prove that the main pilot assignment algorithm in this paper can obtain a noticeable performance gain with limited BS antennas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.370-377
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• 2004

In this paper, we present an adaptive modulation technique for orthogonal frequency division multiplexing (OFDM) for broadband wireless communications. Also, using improved channel prediction, we enhance the performance of adaptive OFDM in high mobility environments. Adaptive modulation technique has been shown to achieve reliable high-rate data transmission over frequency-selective fading channel when OFDM is employed. This scheme requires the accurate channel information between two stations for a better performance. In an outdoor high mobility environment, most of adaptive OFDM systems have to be given the channel information transmitted from the receiver. Even if it is possible, there is some delay. Moreover, the channel impulse response between two stations is very rapidly varied. If the channel information is obsolete at the time of transmission, then poor system performance will result. In order to solve this problem, we propose adaptive OFDM with improved channel predictor. The proposed bit allocation algorithm has a lower complexity and the proposed scheme mitigates the effect of channel delay. Robust approach is less sensitive to outdated channel information. Performance results show that the proposed scheme can achieve considerable performance enhancement.

• MALSORI
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• no.50
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• pp.111-122
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• 2004

Automatic detection of laryngeal diseases by voice is attractive because of its non-intrusive nature. Cepstrum based approach to detect laryngeal cancer shows reliable performance even when the periodicity of voice signals is severely lost, but it has a drawback that it is not robust to channel mismatch due to different microphone characteristics. In this paper, to deal with mismatched training and test microphone conditions, we investigate channel compensation techniques such as Cepstral Mean Subtraction (CMS) and Pole Filtered CMS (PFCMS). According to our experiments, PFCMS yields better performance than CMS. By using PFCMS, we obtained 12% and 40% error reduction over baseline and CMS, respectively.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.588-591
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• 2004

This paper describes a new approach to Internet host mobility. We argue that local mobility, the performance of existing mobile host protocol can be significantly improved. It proposes Fast Moving Detection scheme that based on neighbor AP channel information and moving detection table. And, it composes Local Area Clustering Path (LACP) domain that collected in AP's channel information and MN interface information. It stored the roaming table to include channel information and moving detection. Those which use the proposal scheme will need to put LACP information into the beacon or probe frame. Each AP uses scheme to inform available channel information to MN. From the simulation result, we show that the proposed scheme is advantageous over the legacy schemes in terms of the burst blocking probability and the link utilization.

• Transactions of Materials Processing
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• v.15 no.5 s.86
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• pp.382-386
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• 2006

Preform design is an effective means of achieving the homogeneous deformation of workpiece materials and decreased load in metal forming. However, this approach has not been applied to equal channel angula. pressing (ECAP). In this paper, plastic deformation behavior of workpieces having four different preform shapes during ECAP was investigated using finite element analyses. The results indicated that a preform design of the workpiece head has a beneficial effect on homogeneous deformation, reducing the maximum pressing load at the initial stage and eliminating folding defects at strain concentration points.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.6
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• pp.418-429
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• 2016

In this paper, we propose a hybrid Wyner-Ziv video coding structure that combines conventional motion predictive video coding and Wyner-Ziv video coding to eliminate the feedback channel, which is a major practical problem in applications using the Wyner-Ziv video coding approach. The proposed method divides a hybrid frame into two regions. One is coded by a motion predictive video coder, and the other by the Wyner-Ziv coding method. The proposed encoder estimates side information with low computational complexity, using the coding information of the motion predictive coded region, and estimates the number of syndrome bits required to decode the region. The decoder generates side information using the same method as the encoder, which also reduces the computational complexity in the decoder. Experimental results show that the proposed method can eliminate the feedback channel without incurring a significant rate-distortion performance loss.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.127-136
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• 2008

For mobile wireless systems with full frequency reuse, co-channel interference near the cell coverage boundaries has a significant impact on the signal reception performance. This paper addresses an approach to efficiently mitigate the effect of downlink co-channel interference when multi-antenna terminals are used in cellular environments, by proposing a signal detection strategy combined with a system-level coordination for dynamic frequency reuse. We demonstrate the utilization of multi-antennas to perform spatial demultiplexing of both the desired signal and interfering signals from adjacent cells results in significant improvement of spectral efficiency compared to the maximal ratio combining (MRC) performance, especially when an appropriate frequency reuse based on the traffic loading condition is coordinated among cells. Both analytic expressions for the capacity and experimental results using the adaptive modulation and coding (AMC) are used to confirm the performance gain. The robustness of the proposed scheme against varying operational conditions such as the channel estimation error and shadowing effects are also verified by simulation results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.49-55
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• 2008

To address the convergence issue of power control algorithms, a number of algorithms have been developed hat shape the dynamics of up-link power control for cellular network. Power algorithms based on fixed point iterations can be accelerated by the use of various methods, one of the simplest being the use of Newton iterations, however, this method has the disadvantage which not only needs derivatives of the cost function but also may be weak to noisy environment. we showed performance of the power control schemes to solve the fixed point problem under static or stationary channel. They proved goof performance to solve the fixed point problem due to their predictor based optimal control and quadratic convergence rate. Here, we apply the proposed power control schemes to the problem of the dynamic channel or to dynamic time varying link gains. The rigorous simulation results demonstrated the validity of our approach.

• Journal of Communications and Networks
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• v.10 no.1
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• pp.38-43
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• 2008

In this paper, adaptive channel borrowing approach fuzzy neural networks for load balancing (ACB-FNN) is presented to maximized the number of served calls and the depending on asymmetries traffic load problem. In a wireless network, the call's arrival rate, the call duration and the communication overhead between the base station and the mobile switch center are vague and uncertain. A new load balancing algorithm with cell involved negotiation is also presented in this paper. The ACB-FNN exhibits better learning abilities, optimization abilities, robustness, and fault-tolerant capability thus yielding better performance compared with other algorithms. It aims to efficiently satisfy their diverse quality-of-service (QoS) requirements. The results show that our algorithm has lower blocking rate, lower dropping rate, less update overhead, and shorter channel acquisition delay than previous methods.