Electrokinetically driven flow mixing utilizing chaotic electric fields

This paper presents a novel microfluidic mixing scheme in which the species streams are mixed via the application of chaotic electric fields to four electrodes mounted on the upper and lower surfaces of the mixing chamber. Numerical simulations are performed to analyze the effects of the resulting chaotic electrokinetic driving forces on the fluid flow characteristics within the micromixer and the corresponding mixing performance. During simulation, chaotic oscillating electric potentials are derived using a Duffing–Holmes chaos system. Simulation results indicate that the chaotic electrokinetic driving forces induce a complex flow behavior within the micromixer which results in efficient mixing of the two species streams. It is shown that mixing efficiencies up to 95% can be obtained in the novel micromixer.     

Visualization exploration and encapsulation via a spreadsheet-likeinterface

Exploring complex, very large data sets requires interfaces to present and navigate through the visualization of the data. Two types of audience benefit from such coherent organization and representation: first, the user of the visualization system can examine and evaluate their data more efficiently; second, collaborators or reviewers can quickly understand and extend the visualization. The needs of these two groups are addressed by the spreadsheet-like interface described in this paper. The interface represents a 2D window in a multidimensional visualization parameter space. Data is explored by navigating this space via the interface. The visualization space is presented to the user in a manner that clearly identifies which parameters correspond to which visualized result. Operations defined on this space can be applied which generate new parameters or results. Combined with a general-purpose interpreter, these functions can be utilized to quickly extract desired results. Finally, by encapsulating the visualization process, redundant exploration is eliminated and collaboration is facilitated. The efficacy of this novel interface is demonstrated through examples using a variety of data sets in different domains     

Digital secure communication via chaotic systems

This paper presents a novel secure communication system for digital signal transmissions. It contains four important parts: modulation, chaotic transmitter, chaotic receiver, and demodulation. The modulation mechanism is to modulate each of delivered bit information to be a carrier signal in the continuous form. Then this carrier signal is taken as a parameter of the chaotic system, called the unified chaotic system. Such a system possesses three different types of chaos characterizations depending on its system's parameter, and this guarantees the communication security more. In the public channel, only three chaotic state variables are delivered and this means that the important carrier information is efficiently screened. According to chaotic states received in the receiver terminal, the continuous carrier signal is decrypted using certain adaptation mechanisms. Finally, the proposed demodulation method can successfully recover the original bit information which is embedded in the communication systems. Some simulation results are provided to verify the efficiency of the proposed secure communication system.     

Accelerated value iteration via Anderson mixing

In this paper,we introduce the Anderson acceleration technique developed to be applied to reinforcement learning tasks.We develop an accelerated value iteration...     

Particle mixing and reactive front motions in chaotic but closed shallow flows

A numerical study is presented of wind-induced active mixing and transport processes in closed shallow flows that are able to support chaotic advection. The wind-induced non-linear shallow water flow field is predicted using a quadtree grid based Godunov-type finite volume solver. Particles are tracked by numerically integrating the advection equations using velocity information interpolated from the predicted flow field. In complex oscillating flows, storage of all the necessary velocity information becomes problematical. Instead, we utilize the mean field and the first few dominant unsteady contributions as determined using Singular Value Decomposition. The advected particles are assumed to support autocatalytic reaction defined as A + B → 2B. Wind-induced reactive particle advection is considered in a realistic mine tailings pond with somewhat idealized bed topography. The reactive process reaches a stationary stage where reaction products occupy the whole closed flow domain. However, in the transient stage, particles undergo active advection and trace out filamentary structures that are similar to those in open flows. Because of the impossibility of particle escape and the global fine-scale chaotic mixing, the initial stages of chaotic mixing in closed flows are more efficient than in open flows. The results qualitatively validate a surface reaction theory derived by Károlyi and Tél [Károlyi G, Tél T. Chemical transients in closed chaotic flows: the role of effective dimensions. Phys Rev Lett 2005;95:264501-1-4] for closed systems.     

帐篷混沌序列稀疏测量矩阵构造

测量矩阵的构造是压缩感知(CS)中重要的研究内容之一.利用混沌系统伪随机性、遍历性的特点,提出了一种基于帐篷混沌序列构造确定性稀疏随机矩阵的方法.对混沌系统生成的确定性序列进行了间隔采样,采样后的序列满足统计独立性,然后通过符号函数映射,生成了具有稀疏性质的伪随机序列,进而构造出混沌稀疏测量矩阵.仿真实验表明:该方法构造出的混沌稀疏测量矩阵与高斯随机矩阵、稀疏随机矩阵及Bernoulli随机矩阵相比,具有类似的重构性能.混沌系统参数与初值固定时,构造的混沌稀疏测量矩阵是确定的,计算复杂度小且硬件上容易实现.     

Multipurpose watermarking scheme via intelligent method and chaotic map

Multimedia Tools and Applications - In this paper, we propose a novel multipurpose intelligent image watermarking scheme for both content authentication and copyright protection. To achieve this,...     

Synchronization of coupled chaotic FitzHugh-Nagumo neurons via Lyapunov functions

After investigating the effect of the frequency of an external electrical stimulation on the chaotic dynamics of a single FitzHugh-Nagumo (FHN) neuron, this paper derives both a sufficient and a necessary condition of the coupling coefficient for self-synchronization of two interacting FHN neurons by using the Lyapunov function method and the largest transverse Lyapunov exponent, respectively. Also, for the cases that self-synchronization is not achieved through the coupling coefficient, a feedback control law for synchronization using the Lyapunov method is investigated. The performance of the proposed control law is compared with that of an existing one in the literature. Simulation results are provided.     

A numerical design study of chaotic mixing of magnetic particles in a microfluidic bio-separator

A two-dimensional numerical investigation into the mixing of magnetic microparticles with bio-cells in a chaotic micromixer is carried out by using a multiphysics finite element analysis package. Fluid and magnetic problems are simulated in steady-state and time-dependent modes, respectively. Intensity of segregation is utilized as the main index to examine the efficiency of the mixer. Trajectories of the particles are used in order to detect chaos in their motion and quantify its extent. Moreover, probability of the collision between particles and target bio-cells is examined as a supplemental index to study the effects of driving parameters on the mixing process. Simulation results reveal that while in some ranges of operating conditions all indices are in good agreement, there are some ranges where they appear to predict contradicting results which is discussed in details. It is found that optimum operating conditions for the system is obtained when the Strouhal number is less than 0.6, which corresponds to the efficiency of about 85% in a mixing length of 500 μm (The mixer design described here is patent pending).     

Robust synchronization of fractional-order unified chaotic systems via linear control

A new scheme for accomplishing synchronization between two fractional-order unified chaotic systems is proposed in this paper. The scheme does not require that the nonlinear dynamics of the synchronization error system must be eliminated. Moreover, the parameter of the systems does not have to be known. A controller is a linear feedback controller, which is simple in implementation. It is designed based on an LMI condition. The LMI condition guarantees that the synchronization between the slave system and the master system is achieved. Numerical simulations are performed to demonstrate the effectiveness of the proposed scheme.     

基于Logistic映射的混沌跳频信号发生器设计与实现

混沌数字序列以其优良的伪随机特性,在扩频通信中展示出潜在的应用前景.在Logistic映射的基础上,通过混沌序列当前值与前2个值之间的逻辑运算,并由m序列控制其运算关系与系数,提出一种复杂度更高的用于混沌扩频的数字序列.利用MCS-51单片机作为跳频图案的生成平台以及锁相环电路构成频率合成器,实现了跳速1 000跳/s、频点数为256、频率范围从15 MHz～17.5 MHz的混沌跳频信号发生器.     

Microfluidic encapsulation of cells in alginate particles via an improved internal gelation approach

An improved internal gelation approach is developed to encapsulate single mammalian cells in monodisperse alginate microbeads as small as 26 μm in diameter and at rates of up to 1 kHz with high cell viability. The cell damage resulting from contact with calcium carbonate nanoparticles as gelation reagents is eliminated by employing a co-flow microfluidic device, and the cell exposure to low pH is minimized by a chemically balanced off-chip gelation step. These modifications significantly improve the viability of cells encapsulated in gelled alginate particles. Two different mammalian cell types are encapsulated with viability of over 84 %. The cells are functional and continue to grow inside the microparticles.     

Controlling chaotic and hyperchaotic systems via a simple adaptive feedback controller

This paper investigates the problem of chaos control, and proposes a simple adaptive feedback control method for it under a reasonable assumption. In comparison with previous methods, the present control technique is simple both in the form of the controller and in its application. A numerical example using the Genesio chaotic system verifies the effectiveness and correctness of the proposed approach.     

3D textured model encryption via 3D Lu chaotic mapping

In the emerging Virtual/Augmented Reality (VR/AR) era, three dimensional (3D) content will be popularized just as images and videos today. The security and privacy of these 3D contents should be taken into consideration. 3D contents contain surface models and solid models. Surface models include point clouds, meshes and textured models. Previous work mainly focused on the encryption of solid models, point clouds and meshes. This work focuses on the most complicated 3D textured model. We propose a 3D Lu chaotic mapping based encryption method for 3D textured models. We encrypt the vertices, polygons, and textures of 3D models separately using the 3D Lu chaotic mapping. Then the encrypted vertices, polygons and textures are composited together to form the final encrypted 3D textured model. The experimental results reveal that our method can encrypt and decrypt 3D textured models correctly. Furthermore, typical statistic and brute-force attacks can be resisted by the proposed method.     

Parameter estimation for chaotic systems via a hybrid flower pollination algorithm

Neural Computing and Applications - Parameter estimation is a fundamental research issue which has attracted great concern in the control and synchronization of chaotic systems. This problem can be...     

TI DSKplus Board在房间声回授通道特性测量中的应用

介绍一种新的测量房间声回授通道特性的实验方法。用TI（Texas Instruments）公司提供的DSKplus Board开发套件,实现数据的实时发送和采集,并把采集的数据送入主机保存,以备主机进行房间声回波通道特性的分析计算。     

Microfluidic mixing via transverse electrokinetic effects in a planar microchannel

A new micromixer incorporating integrated electrodes deposited on the bottom surface of a glass/PDMS microchannel is used to induce a localized, perpendicular electric field within pressure driven axial flow. The presence of the electric field drives electro-osmotic flow in the transverse direction along the channel walls, creating helical motion that serves to mix the fluid. A numerical model is used to describe the three-dimensional flow field, where characterization is performed via particle tracking of passive tracer particles, and the conditional entropy (S _lc) is utilized to approximate the extent of mixing along cross-sectional planes. The geometrical parameters and operating conditions of the numerical model are used to fabricate an experimental device, and fluorescence microscopy measurements are used to verify mixing of rhodamine B across the width of the microchannel for a wide range of fluid flow rates. The results demonstrate that under certain operating conditions and selective placement of the electrode gaps along the width of the microchannel, efficient mixing can be achieved within 6 mm of the inlet.

QoS-supported On-chip Communication for Multi-processors

We present a Quality of Service (QoS)-supported on-chip communication that increases the shared communication resources for multi-processor systems on chip. Time-critical embedded systems require tight guaranteed services in terms of throughput, latency etc. in order to comply to hard real-time constraints. Typically, guaranteed-service schemes require dedicated/reserved resources (i.e. links) for communication and thus suffer from low resource utilization. So improving the bandwidth utilization by using the unused bandwidth among the other competing transactions in a fair fashion is an important issue. To the best of our knowledge, we are presenting the first approach for on-chip communication that provides a high resource utilization under a transaction-specific, flexible communication scheme. It provides tight time-related guarantees through our bounded arbitration scheme considering the lower and the upper bounds for each type of transactions. We demonstrate its advantages by means of a complete MPEG4 video decoder case study analysis and achieve under certain constraints a bandwidth utilization of up to 100% and 97% on average with a guaranteed 100% bandwidth. Thus, we provide an on-chip communication scheme that provides high bandwidth utilization while providing tight guarantee. Large parts of this work have previously been published at the IEEE International Conference on Hardware/Software Codesign and System Synthesis (Codes+ISSS), 2006.     

On-chip optical interconnect using visible light

We propose and fabricate a monolithic optical interconnect on a GaN-on-silicon platform using a wafer-level technique. Because the InGaN/GaN multiple-quantum-well diodes (MQWDs) can achieve light emission and detection simultaneously, the emitter and collector sharing identical MQW structure are produced using the same process. Suspended waveguides interconnect the emitter with the collector to form in-plane light coupling. Monolithic optical interconnect chip integrates the emitter, waveguide, base, and collector into a multi-component system with a common base. Output states superposition and 1×2 in-plane light communication are experimentally demonstrated. The proposed monolithic optical interconnect opens a promising way toward the diverse applications from in-plane visible light communication to light-induced artificial synaptic devices, intelligent display, on-chip imaging, and optical sensing.     

Differential coupling contributes to synchronization via a capacitor connection between chaotic circuits

Nonlinear oscillators and circuits can be coupled to reach synchronization and consensus. The occurrence of complete synchronization means that all oscillators can maintain the same amplitude and phase, and it is often detected between identical oscillators. However, phase synchronization means that the coupled oscillators just keep pace in oscillation even though the amplitude of each node could be different. For dimensionless dynamical systems and oscillators, the synchronization approach depends a great deal on the selection of coupling variable and type. For nonlinear circuits, a resistor is often used to bridge the connection between two or more circuits, so voltage coupling can be activated to generate feedback on the coupled circuits. In this paper, capacitor coupling is applied between two Pikovsk-Rabinovich (PR) circuits, and electric field coupling explains the potential mechanism for differential coupling. Then symmetric coupling and cross coupling are activated to detect synchronization stability, separately. It is found that resistor-based voltage coupling via a single variable can stabilize the synchronization, and the energy flow of the controller is decreased when synchronization is realized. Furthermore, by applying appropriate intensity for the coupling capacitor, synchronization is also reached and the energy flow across the coupling capacitor is helpful in regulating the dynamical behaviors of coupled circuits, which are supported by a continuous energy exchange between capacitors and the inductor. It is also confirmed that the realization of synchronization is dependent on the selection of a coupling channel. The approach and stability of complete synchronization depend on symmetric coupling, which is activated between the same variables. Cross coupling between different variables just triggers phase synchronization. The capacitor coupling can avoid energy consumption for the case with resistor coupling, and it can also enhance the energy exchange between two coupled circuits.