Non-cooperative Systems Research Articles

Monotonicity methods for noncooperative elliptic systems

We show how monotonicity methods combined with infinite-dimensional sandwich pairs can be used to solve very general systems of equations that are not semibounded.

On Non-Cooperative Block-Faded Orthogonal Multiple Access Schemes with Correlated Sources

In this paper, we study the performance of non-cooperative multiple access systems with noisy separated channels, where correlated sources communicate to an access point (AP) through block-faded links. In the considered scenario, perfect channel state information (CSI) is assumed at the receiver while no CSI is available at the transmitters. We first consider uncoded transmissions from the sources to the AP, which exploits the source correlation to carry out joint channel detection (JCD). In this scenario, we propose an analytical approach to evaluate the achievable performance in terms of average bit error rate (BER). We then investigate the impact of coding, considering the same fixed coding scheme at each source. Then, we consider an extrinsic information transfer (EXIT) chart-based framework to optimize the design of concatenated and low-density parity-check (LDPC) codes for JCD schemes.

Existence of radial stationary solutions for a system in combustion theory

In this paper, we construct radially symmetric solutions of a nonlinear noncooperative elliptic system derived from a model for flame balls with radiation losses. This model is based on a one step kinetic reaction and our system is obtained by approximating the standard Arrehnius law by an ignition nonlinearity, and by simplifying the term that models radiation. We prove the existence of 2 solutions using degree theory.

Cooperative Pricing Decision Model in Supply Chain

This paper considers a retailer who wishes to procure a kind of product to meet customer’s demand and shows that the supplier and the retailer’s cooperetive pricing decision . We gives the prices of Pareto optimal equlibrium and compares the prices with that of cooperative supply chain and find that noncooperative system profit is less than cooperative system profit. Furthermore, we shows that on some assumption, Pareto optimal price policy is equivalent to jointly decision policy, i.e., Pareto optimal price policy can reach the whole system maximum profit, and the numerical example indicates that with the retailer operating cost increasing, the total profit of supply chain is decreasing.

Energy efficient resource allocation in non-cooperative multi-cell OFDMA systems

Energy efficient resource allocation in non-cooperative multi-cell OFDMA systems

Analysis of Heterotropic Cooperativity in Cytochrome P450 3A4 Using α-Naphthoflavone and Testosterone

Cytochrome P450 3A4 (CYP3A4) displays non-Michaelis-Menten kinetics for many of the substrates it metabolizes, including testosterone (TST) and α-naphthoflavone (ANF). Heterotropic effects between these two substrates can further complicate the metabolic profile of the enzyme. In this work, monomeric CYP3A4 solubilized in Nanodiscs has been studied for its ability to interact with varying molar ratios of ANF and TST. Comparison of the observed heme spin state, NADPH consumption, and product formation rates with a non-cooperative model calculated from a linear combination of the global analysis of each substrate reveals a detailed landscape of the heterotropic interactions and indicates negligible binding cooperativity between ANF and TST. The observed effect of ANF on the kinetics of TST metabolism is due to the additive action of the second substrate with no specific allosteric effects.

Extending the notion of rationality of selfish agents: Second Order Nash equilibria

Motivated by the increasing interest of the Computer Science community in the study and understanding of non-cooperative systems, we present a novel model for formalizing the rational behavior of agents with a more farsighted view of the consequences of their actions. This approach yields a framework creating new equilibria, which we call Second Order equilibria, starting from a ground set of traditional ones. By applying our approach to pure Nash equilibria, we define the set of Second Order pure Nash equilibria and present their applications to the Prisoner’s Dilemma game, to an instance of Braess’s Paradox in the W a r d r o p model and to the K P model with identical machines.

Unequal Error Protection (UEP) Image Transmission System with Lifting Wavelet Transform (LWT) Based Reed Solomon (RS) Coded Cooperation Scheme

This paper presents a new unequal error protection (UEP) image transmission system that incorporates a Lifting Wavelet Transform (LWT) and Reed Solomon (RS) coded cooperation scheme to increase image transmission diversity, as well as save transmission bandwidth. Having a partner to assist direct communication increases the resilience of low frequency subband data against an error-prone fading channel. Low frequency subbands are partitioned into two sets of data and transmitted using the RS coded cooperation scheme. High frequency subbands data are transmitted directly to a base station. Results show that the new UEP image transmission system using LWT based RS coded cooperation scheme achieves diversity gains of around 10dB, with channel SNR from 10 to 20dB, compared with the image transmission system with non-cooperative system under slow Rayleigh fading channel for all levels of LWT decomposition. In addition, the new UEP image transmission system using LWT based RS coded cooperation scheme with one level of wavelet decomposition offers around 37.5% bandwidth gain (s), compared with the system without LWT, which incurs a reduction of 3dB in reconstructed image quality.

Existence of radial stationary solutions for a system in combustion theory

In this paper, we construct radially symmetric solutions of a nonlinear non-cooperative elliptic system derived from a model for flame balls with radiation losses. This model is based on a one step kinetic reaction and our system is obtained by approximating the standard Arrehnius law by an ignition nonlinearity, and by simplifying the term that models radiation. We prove the existence of 2 solutions using degree theory.

Discussion on: “On a Small Gain Theorem for ISS Networks in Dissipative Lyapunov Form”

relating the stability estimates of the subsystems. The order of this system is n — the number of interconnected subsystems. It can be shown that stability properties of this comparison system can be translated to the same stability properties for the original composite system, as undertaken in [11]. In a sense, cooperative systems like (2) are at the core of large-scale systems analysis in the ISS framework, and it can be expected that the constructions in this paper can be translated back to comparison systems. The geometric construction in the present paper further motivates the stability analysis and tailored design ofmore general networks of nonlinear systemswith corresponding non-cooperative comparison systems. While input-tostate stability and related concepts provide worst-case estimates, the resulting theory will always be conservative for systems where the nature of feedback is not that of a disturbance but can have beneficial effects on the stability of the system. Especially in contexts where synchronization or consensus is desired, interconnection topologies cease to yield purely cooperative comparison dynamics and it remains to future research to extend constructive methods as detailed in this paper to this broader scope.

Joint Power Allocation and Interference Mitigation Techniques for Cooperative Spread Spectrum Systems with Multiple Relays

This paper presents joint power allocation and interference mitigation techniques for the downlink of spread spectrum systems which employ multiple relays and the amplify and forward cooperation strategy. We propose a joint constrained optimization framework that considers the allocation of power levels across the relays subject to an individual power constraint and the design of linear receivers for interference suppression. We derive constrained minimum mean-squared error (MMSE) expressions for the parameter vectors that determine the optimal power levels across the relays and the linear receivers. In order to solve the proposed optimization problem efficiently, we develop joint adaptive power allocation and interference suppression algorithms that can be implemented in a distributed fashion. The proposed stochastic gradient (SG) and recursive least squares (RLS) algorithms mitigate the interference by adjusting the power levels across the relays and estimating the parameters of the linear receiver. SG and RLS channel estimation algorithms are also derived to determine the coefficients of the channels across the base station, the relays and the destination terminal. The results of simulations show that the proposed techniques obtain significant gains in performance and capacity over non-cooperative systems and cooperative schemes with equal power allocation.

Noncooperative elliptic systems

We show how monotonicity methods combined with infinite dimensional sandwich pairs can be used to solve very general systems of equations that are not semibounded.

Bimodal gene expression in noncooperative regulatory systems

Bimodality of gene expression, as a mechanism contributing to phenotypic diversity, enhances the survival of cells in a fluctuating environment. To date, the bimodal response of a gene regulatory system has been attributed to the cooperativity of transcription factor binding or to feedback loops. It has remained unclear whether noncooperative binding of transcription factors can give rise to bimodality in an open-loop system. We study a theoretical model of gene expression in a two-step cascade (a deterministically monostable system) in which the regulatory gene produces transcription factors that have a nonlinear effect on the activity of the target gene. We show that a unimodal distribution of transcription factors over the cell population can generate a bimodal steady-state output without cooperative transcription factor binding. We introduce a simple method of geometric construction that allows one to predict the onset of bimodality. The construction only involves the parameters of bursting of the regulatory gene and the dose-response curve of the target gene. Using this method, we show that the gene expression may switch between unimodal and bimodal as the concentration of inducers or corepressors is varied. These findings may explain the experimentally observed bimodal response of cascades consisting of a fluorescent protein reporter controlled by the tetracycline repressor. The geometric construction provides a useful tool for designing experiments and for interpretation of their results. Our findings may have important implications for understanding the strategies adopted by cell populations to survive in changing environments.

Global bifurcations of critical orbits of [formula omitted]-invariant strongly indefinite functionals

Let H be a separable Hilbert space which is an orthogonal representation of a compact Lie group G and let Φ : H → R be a G -invariant strongly indefinite functional of the class C 1 . To study critical orbits of Φ we have defined the degree for G -invariant strongly indefinite functionals, which is an element of the Euler ring U ( G ) . Using this degree we have formulated the Rabinowitz alternative for G -invariant strongly indefinite functionals. The abstract results are applied to the study of global bifurcations of weak solutions of non-cooperative systems of elliptic differential equations.

Coordinating ordering and pricing decisions in a two-stage distribution system with price-sensitive demand through short-term discounting

We consider a short-term discounting model in which the distributor offers a discounted price for the retailers’ orders placed at the beginning of its replenishment cycle, in a non-cooperative distribution system with one distributor and multiple retailers, each facing price-sensitive demand. We examine the value of the price discount strategy as a mechanism for the distributor to coordinate the retailers’ ordering and pricing decisions under two common types of demand, linear demand in price and constant elasticity demand in price. Our numerical study reveals that, in the presence of homogeneous retailers (namely, retailers with identical demand rates), the distributor’s profit improvement due to coordination generally decreases as the number of retailers or the inventory holding cost rate increases, but increases as price elasticity increases. Although an increase in the inventory holding cost rate has a negative effect on the distributor’s profit, it may have a positive effect on the retailers’ profits. We further find that with heterogeneous retailers (namely, retailers with different demand rates), offering a discounted price under linear demand benefits the distributor when both the inventory holding cost rate and the variation in demand are either small or large. This cross effect, however, is absent under constant elasticity demand.

Existence and multiplicity of solutions for asymptotically linear noncooperative elliptic systems

Using the minimax methods in critical point theory and a generalized Landesman–Lazer type condition, we establish two existence results of solutions for asymptotically linear noncooperative elliptic systems at resonance. Besides this, we obtain two solutions in the case of near resonance.

Exploiting Cooperative Advantages in Slotted ALOHA Random Access Networks

In cooperative systems, users achieve spatial diversity and multihop gains by transmitting packets over multiple independent fading paths provided by their partners. Most previous works on cooperative communications focus on the physical layer aspects such as coding, modulation, and transceiver signal processing techniques. In this work, we study the advantages of user cooperation from a MAC layer perspective and devise queueing strategies to exploit cooperative gains in random access networks. Based on the conventional slotted ALOHA protocol, we propose a simple cooperative transmission mechanism for a two-user cooperative pair. We derive the two-user stability region of the proposed system and show the improvements compared to noncooperative systems. The benefits can be attributed to both physical layer cooperation, where users with good channels may relay for those with bad channels, and MAC layer cooperation, where system parameters can be chosen to enhance cooperation and reduce competition. Then, we extend the proposed strategy to a finite-user system that consists of multiple cooperative pairs. By treating each pair as a single transmission entity, we derive inner bounds for the finite-user stability region and propose a ranking system to characterize the transmission entities' relative tendency of being stable (or unstable).

A Precoded OFDMA System with User Cooperation

A new cooperative scheme for a two-user orthogonal frequency division multiple access (OFDMA) uplink communication scenario is proposed. Each user is equipped with one transmit/receive antenna. Before transmission, inter-block linear precoding is introduced to pairs of blocks. The cooperative transmission is implemented in cycles of three time slots. During each slot, a user transmits either his data, or a weighted mixture of his data and the data that he received in previous slots of the same cycle. The weights are obtained in an optimum fashion, so that a user that faces deep fading on certain subcarriers can benefit from the other user's channel, without taxing significantly the resources of that user. It is shown that the proposed scheme achieves the maximum available diversity for both users (full cooperation), or for the weak user (half cooperation) without increasing the number of antennas needed as compared to an energy-equivalent noncooperative OFDMA system that also uses inter-block precoding. Further, the proposed use of inter-block precoding allows one to exploit the cooperation induced diversity in 1.5 slots on the average; 2 slots would be needed if intra-block precoding was used instead.

Accurate Iris Segmentation Method for Non-Cooperative Iris Recognition System

Problem statement: Iris segmentation is one of the most important ste ps in iris recognition system and determines the accuracy of matching. Most segmentation methods in the literature assumed that the inner and outer boundaries of the iris wer e circular. Hence, they focus on determining model parameters that best fit these hypotheses. This is a source of error, since the iris boundaries were n ot exactly circles. Approach: In this study we proposed an accurate iris segment ation method that employs Chan-Vese active contour method to extract the iris from his surrounding structures. Results: The proposed method was implemented and tested on the challenging UBIRIS database the results indicated the efficacy of the proposed meth od. Conclusion: The experimental results showed that the proposed method localized the iris area probabl y even when the eyelids occlude same part of iris.

Scale Invariant Gabor Descriptor-Based Noncooperative Iris Recognition

A new noncooperative iris recognitionmethod is proposed. In this method, the iris features are extracted using a Gabor descriptor. The feature extraction and comparison are scale, deformation, rotation, and contrast-invariant. It works with off-angle and lowresolution iris images. The Gabor wavelet is incorporated with scale-invariant feature transformation (SIFT) for feature extraction to better extract the iris features. Both the phase and magnitude of the Gabor wavelet outputs were used in a novel way for local feature point description. Two feature region maps were designed to locally and globally register the feature points and each subregion in the map is locally adjusted to the dilation/contraction/deformation. We also developed a video-based noncooperative iris recognition system by integrating video-based non-cooperative segmentation, segmentation evaluation, and score fusion units. The proposed method shows good performance for frontal and off-angle iris matching. Video-based recognition methods can improve non-cooperative iris recognition accuracy.