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Ning Cai

Publications and source records attributed to Ning Cai.

At least 37 records · Page 2Linked to original sources
arXiv2018

Message Transmission over Classical Quantum Channels with a Jammer with Side Information: Message Transmission Capacity and Resources

In this paper we propose a new model for arbitrarily varying classical-quantum channels. In this model a jammer has side information. We consider two scenarios. In the first scenario the jammer knows the channel input, while in the second scenario the jammer knows both the channel input and the message. The transmitter and receiver share a secret random key with a vanishing key rate. We determine the capacity for both average and maximum error criteria for both scenarios. We also establish the strong converse. We show that all these corresponding capacities are equal, which means that additionally revealing the message to the jammer does not change the capacity.

cs.IT↗
arXiv2017

Social Computing Based Analysis on Monogamous Marriage Puzzle of Human

Most of the mammal species hold polygynous mating systems. The majority of the marriage systems of mankind were also polygynous over civilized history, however, socially imposed monogamy gradually prevails throughout the world. This is difficult to understand because those mostly influential in society are themselves benefitted from polygyny. Actually, the puzzle of monogamous marriage could be explained by a simple mechanism, which lies in the sexual selection dynamics of civilized human societies, driven by wealth redistribution. The discussions in this paper are mainly based on the approach of social computing, with a combination of both experimental and analytical analysis.

cs.SI↗
arXiv2017

A Distributed Parallel Model to Analyze Journal Impact Factors

A simple abstract model is developed as a parallel experimental basis for the aim of exploring the differences of journal impact factors, particularly between different disciplines. Our model endeavors to simulate the publication and citation behaviors of the articles in the journals belonging to a similar discipline, in a distributed manner. Based on simulation experiments, the mechanism of influence from several fundamental factors to the trend of impact factor is revealed. These factors include the average review cycle, average number of references and yearly distribution of references. Moreover, satisfactory approximation could possibly be observed between certain actual data and simulation results.

cs.DL↗
arXiv2017

On Non-Consensus Motions of Dynamical Linear Multi-Agent Systems

The non-consensus problems of high order linear time-invariant dynamical homogeneous multi-agent systems are concerned. Based on the conditions of consensus achievement, the mechanisms that lead to non-consensus motions are analyzed. Besides, a comprehensive classification for diverse types of non-consensus phases in accordance to the different conditions is conducted, which is jointly depending on the self-dynamics of agents, the interactive protocol and the graph topology. A series of numerical examples are demonstrated to illustrate the theoretical analysis.

eess.SY↗
arXiv2017

On Almost Controllability of Dynamical Complex Networks with Noises

This paper discusses the controllability problem of complex networks. It is shown that almost any weighted complex network with noise on the strength of communication links is controllable in the sense of Kalman controllability. The concept of almost controllability is elaborated by both theoretical discussions and experimental verifications.

eess.SY↗
arXiv2017

Exponent for classical-quantum multiple access channel

In this paper we obtain a lower bound of exponent of average probability of error for classical quantum multiple access channel, which implies that for all rate pairs in the capacity region is achievable by a code with exponential probability of error. Thus we re-obtain the direct coding theorem.

quant-ph↗
arXiv2016

The Classical-Quantum Channel with Random State Parameters Known to the Sender

We study an analog of the well-known Gel'fand Pinsker Channel which uses quantum states for the transmission of the data. We consider the case where both the sender's inputs to the channel and the channel states are to be taken from a finite set (cq-channel with state information at the sender). We distinguish between causal and non-causal channel state information at the sender. The receiver remains ignorant, throughout. We give a single-letter description of the capacity in the first case. In the second case we present two different regularized expressions for the capacity. It is an astonishing and unexpected result of our work that a simple change from causal to non-causal channel state information at the encoder causes the complexity of a numerical computation of the capacity formula to change from trivial to seemingly difficult. Still, even the non-single letter formula allows one to draw nontrivial conclusions, for example regarding continuity of the capacity with respect to changes in the system parameters. The direct parts of both coding theorems are based on a special class of POVMs which are derived from orthogonal projections onto certain representations of the symmetric groups. This approach supports a reasoning that is inspired by the classical method of types. In combination with the non-commutative union bound these POVMs yield an elegant method of proof for the direct part of the coding theorem in the first case.

quant-ph↗
arXiv2016

On Quantitatively Measuring Controllability of Complex Networks

This letter deals with the controllability issue of complex networks. An index is chosen to quantitatively measure the extent of controllability of given network. The effect of this index is analyzed based on empirical studies on various classes of network topologies, such as random network, small-world network, and scale-free network.

eess.SY↗
arXiv2015

A Novel Clustering Approach Based on Group Quasi-Consensus of Unstable Dynamic Linear High-Order Multi-Agent Systems

This paper introduces a novel approach of clustering, which is based on group consensus of dynamic linear high-order multi-agent systems. The graph topology is associated with a selected multi-agent system, with each agent corresponding to one vertex. In order to reveal the cluster structure, the agents belonging to a similar cluster are expected to aggregate together. As theoretical foundation, a necessary and sufficient condition is given to check the group consensus. Two numerical instances are shown to illustrate the process of approach.

eess.SY↗
arXiv2014

Agent-Based Model for Rural-Urban Migration: A Dynamic Consideration

This paper develops a dynamic agent-based model for rural-urban migration, based on the previous relevant works. The model conforms to the typical dynamic linear multi-agent systems model concerned extensively in systems science, in which the communication network is formulated as a digraph. Simulations reveal that consensus of certain variable could be harmful to the overall stability and should be avoided.

cs.MA↗
arXiv2014

Almost Decouplability of any Directed Weighted Network Topology

This paper introduces a conception that any weighted directed network topology is almost decouplable, which can help to transform the topology into a similar form being composed of uncoupled vertices, and thus reduce the complexity of analysis for networked dynamical systems. As an example of its application, the consensus problem of linear multi-agent systems with time-varying network topologies is addressed. As a result, a necessary and sufficient condition for uniform consensus is proposed.

eess.SY↗
arXiv2014

Secrecy capacities of compound quantum wiretap channels and applications

We determine the secrecy capacity of the compound channel with quantum wiretapper and channel state information at the transmitter. Moreover, we derive a lower bound on the secrecy capacity of this channel without channel state information and determine the secrecy capacity of the compound classical-quantum wiretap channel with channel state information at the transmitter. We use this result to derive a new proof for a lower bound on the entanglement generating capacity of compound quantum channel. We also derive a new proof for the entanglement generating capacity of compound quantum channel with channel state information at the encoder.

cs.IT↗
arXiv2014

On Swarm Stability of Linear Time-Invariant Descriptor Compartmental Networks

Swarm stability is concerned for descriptor compartmental networks with linear time-invariant protocol. Compartmental network is a specific type of dynamical multi-agent system. Necessary and sufficient conditions for both consensus and critical swarm stability are presented, which require a joint matching between the interactive dynamics of nearest neighboring vertices and the Laplacian spectrum of the overall network topology. Three numerical instances are illustrated to verify the theoretical results.

eess.SY↗
arXiv2013

Optimal Amplify-and-Forward Schemes for Relay Channels with Correlated Relay Noise

This paper investigates amplify-and-forward (AF) schemes for both one and two-way relay channels. Unlike most existing works assuming independent noise at the relays, we consider a more general scenario with correlated relay noise. We first propose an approach to efficiently solve a class of quadratically constrained fractional problems via second-order cone programming (SOCP). Then it is shown that the AF relay optimization problems studied in this paper can be incorporated into such quadratically constrained fractional problems. As a consequence, the proposed approach can be used as a unified framework to solve the optimal AF rate for the one-way relay channel and the optimal AF rate region for the two-way relay channel under both sum and individual relay power constraints. In particular, for one-way relay channel under individual relay power constraints, we propose two suboptimal AF schemes in closed-form. It is shown that they are approximately optimal in certain conditions of interest. Furthermore, we find an interesting result that, on average, noise correlation is beneficial no matter the relays know the noise covariance matrix or not for such scenario. Overall, the obtained results recover and generalize several existing results for the uncorrelated counterpart. (unsubmitted)

cs.IT↗
arXiv2012

Multi-hop Analog Network Coding: An Amplify-and-Forward Approach

In this paper, we study the performance of an amplify-and-forward (AF) based analog network coding (ANC) relay scheme in a multi-hop wireless network under individual power constraints. In the first part, a unicast scenario is considered. The problem of finding the maximum achievable rate is formulated as an optimization problem. Rather than solving this non-concave maximization problem, we derive upper and lower bounds for the optimal rate. A cut-set like upper bound is obtained in a closed form for a layered relay network. A pseudo-optimal AF scheme is developed for a two-hop parallel network, which is different from the conventional scheme with all amplification gains chosen as the maximum possible values. The conditions under which either the novel scheme or the conventional one achieves a rate within half a bit of the upper bound are found. Then we provide an AF-based multi-hop ANC scheme with the two schemes for a layered relay network. It is demonstrated that the lower bound of the optimal rate can asymptotically achieve the upper bound when the network is in the generalized high-SNR regime. In the second part, the optimal rate region for a two-hop multiple access channel (MAC) via AF relays is investigated. In a similar manner, we first derive an outer bound for it and then focus on designing low complexity AF-based ANC schemes for different scenarios. Several examples are given and the numerical results indicate that the achievable rate region of the ANC schemes can perform close to the outer bound.

cs.IT↗
arXiv2011

Convolutional Network Coding Based on Matrix Power Series Representation

In this paper, convolutional network coding is formulated by means of matrix power series representation of the local encoding kernel (LEK) matrices and global encoding kernel (GEK) matrices to establish its theoretical fundamentals for practical implementations. From the encoding perspective, the GEKs of a convolutional network code (CNC) are shown to be uniquely determined by its LEK matrix $K(z)$ if $K_0$, the constant coefficient matrix of $K(z)$, is nilpotent. This will simplify the CNC design because a nilpotent $K_0$ suffices to guarantee a unique set of GEKs. Besides, the relation between coding topology and $K(z)$ is also discussed. From the decoding perspective, the main theme is to justify that the first $L+1$ terms of the GEK matrix $F(z)$ at a sink $r$ suffice to check whether the code is decodable at $r$ with delay $L$ and to start decoding if so. The concomitant decoding scheme avoids dealing with $F(z)$, which may contain infinite terms, as a whole and hence reduces the complexity of decodability check. It potentially makes CNCs applicable to wireless networks.

cs.IT↗
arXiv2011

Analog Network Coding in the Generalized High-SNR Regime

In a recent paper [4], Marić et al. analyzed the performance of the analog network coding (ANC) in a layered relay network for the high-SNR regime. They have proved that under the ANC scheme, if each relay transmits the received signals at the upper bound of the power constraint, the transmission rate will approach the network capacity. In this paper, we consider a more general scenario defined as the generalized high-SNR regime, where the relays at layer $l$ in a layered relay network with $L$ layers do not satisfy the high-SNR conditions, and then determine an ANC relay scheme in such network. By relating the received SNR at the nodes with the propagated noise, we derive the rate achievable by the ANC scheme proposed in this paper. The result shows that the achievable ANC rate approaches the upper bound of the ANC capacity as the received powers at relays in high SNR increase. A comparison of the two ANC schemes implies that the scheme proposed in [4] may not always be the optimal one in the generalized high-SNR regime. The result also demonstrates that the upper and lower bounds of the ANC rate coincide in the limit as the number of relays at layer L-1 dissatisfying the high-SNR conditions tends to infinity, yielding an asymptotic capacity result.

cs.IT↗