Heterogeneous network (HetNet) is a promising technology to improve the capacity of future generations of cellular network, in which a mobile station can be served by multiple base stations (BSs) with different scales...
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ISBN:
(纸本)9781479959532
Heterogeneous network (HetNet) is a promising technology to improve the capacity of future generations of cellular network, in which a mobile station can be served by multiple base stations (BSs) with different scales of coverage range, including short range low power nodes (LPNs). In HetNet, a major challenge is how to provide guaranteed quality-of-service (QoS) for all users. To address this issue, we investigate a practical scenario in which the massive multiple-input multiple-output (MIMO) technology is adopted by the cooperation of one macro-cell BS and several LPNs. Furthermore, we provide a lightweight channel state information (CSI) acquisition scheme for the implementation. Numerical simulation results demonstrate that the signal-to-interference-and noise ratio (SINR) of intended users in LPNs covered with small cells can be significantly increased by this proposed massive MIMO precoding scheme, whereas oppressing the impact on neighboring victim users.
Conventional methods for storing and reproducing task are based on only the information of the actuators in the robot. However, in these methods, reproducing the stored task is difficult when the environment differs f...
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ISBN:
(纸本)9781479917631
Conventional methods for storing and reproducing task are based on only the information of the actuators in the robot. However, in these methods, reproducing the stored task is difficult when the environment differs from that in storing phase. This is because these methods consider a meaningful task as just a motion. In this paper, to reproduce a stored task even if the environment differs from that in storing phase, storage and reproduction of a task based on the controlled variable of a task is proposed. To verify the principle of this proposal, the water pouring task is considered. The proposed method can reproduce the water pouring task even if the initial weight of the water in the bottle differs from that in storing phase. The validity of the proposal is confirmed by experiments using one degree-of-freedom robots.
Virtual network Embedding (VNE) is recognized as the fundamental issue in network virtualization. Previous work in VNE mainly focused on researching efficient static algorithms without considering the dynamic topology...
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Virtual network Embedding (VNE) is recognized as the fundamental issue in network virtualization. Previous work in VNE mainly focused on researching efficient static algorithms without considering the dynamic topology remapping which may have an impact on the mapping efficiency. In this paper, we address the dynamic topology remapping problem and give a classification to clarify the remapping approaches under any circumstances. We find that choosing different strategies between timing, object and algorithm will affect the further mapping schemes.
Harmonic distortion on voltages and currents increases with the increased penetration of Plug-in Electric Vehicle (PEV) loads in distribution systems. Wind Generators (WGs), which are source of harmonic currents, have...
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ISBN:
(纸本)9781467380416
Harmonic distortion on voltages and currents increases with the increased penetration of Plug-in Electric Vehicle (PEV) loads in distribution systems. Wind Generators (WGs), which are source of harmonic currents, have some common harmonic profiles with PEVs. Thus, WGs can be utilized to subside the effect of PEVs on harmonic distortion. This paper studies the impact of PEVs on harmonic distortions and integration of WGs to reduce it. A harmonic decoupled power flow model is developed, where PEVs and WGs are represented by harmonic current loads and sources, respectively. The developed model is first used to solve harmonic power flow on IEEE 34-node distribution test feeder with low, moderate, and high penetrations of PEVs, then its impact on total harmonic distortions (THDs) is studied. Next, optimal size of WGs are calculated using Genetic Algorithm in the test feeder to reduce voltage and current THDs below the IEEE recommended values.
The Hawking temperature for the Schwarzschild black hole is divergent when the mass of the black hole vanishes; however, the corresponding geometry becomes the Minkowski spacetime whose intrinsic temperature is zero. ...
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The Hawking temperature for the Schwarzschild black hole is divergent when the mass of the black hole vanishes; however, the corresponding geometry becomes the Minkowski spacetime whose intrinsic temperature is zero. In connection with this issue, we construct a nonsingular temperature which follows the Hawking temperature for the large black hole, while it vanishes when the black hole is completely evaporated. For the thermodynamics significances of this modified temperature, we calculate thermodynamic quantities and study phase transitions. It turns out that even the small black hole can be stable below a certain temperature, and the hot flat space is always metastable so that it decays into the stable small black hole or the stable large black hole.
In this paper we propose an integrated test environment for combinatorial testing and discuss its realization at macro level. We describe the entities that make up the integrated test environment and their interaction...
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ISBN:
(纸本)9781479980482
In this paper we propose an integrated test environment for combinatorial testing and discuss its realization at macro level. We describe the entities that make up the integrated test environment and their interaction, high-lighting the combinatorial test aspects. The proposed environment can be used for the automated as well as manual testing. Test tools supplied by research institutions and commercial tool vendors need to be integrated to realize the test environment proposed in this paper. The proposed system is theoretical in nature which can be embraced by large scale industrial and research projects to achieve an efficient integrated environment for combinatorial testing. This in turn can aid in the adoption of combinatorial testing to achieve the desired quality improvements in the products.
This paper introduces vehicle trajectory discovery for vehicular wireless networks. Nowadays, GPS-based navigation systems are popular used for providing efficient driving paths for drivers, as well as it's still ...
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Downlink joint processing (JP) between base stations eliminates the inter-cell interference in a cellular system with a frequency reuse factor of one and improves the spectral efficiency of cell-edge users. JP has a h...
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Downlink joint processing (JP) between base stations eliminates the inter-cell interference in a cellular system with a frequency reuse factor of one and improves the spectral efficiency of cell-edge users. JP has a huge impact on both feedback and backhaul load, and thus partial JP was presented to tackle with signaling demand. However, achieving equivalent backhaul reduction based on limited feedback channel state information is challenging when linear techniques, such as zero-forcing beamforming (BF) are used, which led to the use of stochastic algorithms instead. Therefore stochastic multi-start particle swarm optimization algorithm (MSPSOA) is proposed in this paper to achieve backhaul reduction and address the issue of lack of diversity, which is related to the basic particle swarm optimization algorithm (BPSOA). The lack of diversity has been solved in this work by replacing the inactive particles adaptively based on a predefined constant which represents the difference between local best and global best optimization criterion. The performance of the proposed MSPSOA and BPSOA BF is evaluated with respect to full and partial JP using different metrics such as sum-rate, actual interference and convergence using a multipath realistic environment WINNER II channel model. The proposed MSPSOA outperforms BPSOA in terms of average sum-rate by 15.3%, while the actual interference decreased by 14.6% in some conducted scenarios.
Since entering into the era of multi-core CPU, because the traditional K-means clustering algorithm isn't designed focus on parallelization very well, which can't fully utilize the parallel computing power of ...
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