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A novel constant on-time bi-frequency (COT-BF) control technique for switching dc-dc converters operating in discontinuous conduction mode (DCM) is proposed in this paper. The proposed COT-BF control technique realizes the output voltage regulation of switching dc-dc converters by adjusting the combination of high-frequency control pulse and low-frequency control pulse. COT-BF control technique is...
In highway engineering, pre-estimation on the global stability of highway slopes is a key to construction design and safety. The factors on slope stability include geological data, hydrographic data, situation of slopes, the way of cut, and so on. Therefore, a suitable analytical methodology of system engineering integrating the comprehensive qualitative and quantitative information is needed. A multi-level...
This paper proposes a robust guaranteed cost control method for a linear system with norm bounded time varying parametric uncertainties and external disturbance. Using the Lyapunov stability theory and linear matrix inequality method, a robust guaranteed cost control law is derived to guarantee that the closed loop system is not only stable, but also has adequately quadratic and H∞ performance levels...
Witricity is a recent technology for wireless power transfer over a limited distance. In this paper, we investigate a relay effect to extend the distance. The concept of magnetic resonance in strongly coupled regime with more than two resonators is presented. Theoretical analysis is performed based on a set of differential equations and experiments are conducted to demonstrate its effectiveness. Our...
Brain Machine Interface (BMI) systems demand real-time spike sorting to instantaneously decode the spike trains of simultaneously recorded cortical neurons. Real-time spike sorting, however, requires extensive computational power that is not feasible to implement in implantable BMI architectures, thereby requiring transmission of high-bandwidth raw neural data to an external computer. In this work,...
A recent study on witricity (wireless electricity) has demonstrated that wireless energy can be delivered over a moderate distance using strongly coupled magnetic resonance. The objective of this work is to apply the witricity technology to the problem of powering a wireless Body Sensor Network (wBSN). The theory of witricity is investigated using coupled mode theory. Compact witricity resonators...
A processing method of blood cell flow image in micro rectangular capillary is proposed and the recognition and computation procedures are also discussed. According to the characteristics of cell micro-flow image, the image is filtered and enhanced in frequency spectrum, and mathematical morphology operations are applied to recognize and segment the flowing objects in image. With the segmented results,...
Expectation and requirements for future wireless communication systems continue to grow and evolve. Thus, 3GPP has considered LTE/SAE to ensure its competitiveness in the future. In LTE/SAE, one of the recurring problems is dimensioning and testing. Modeling is an effective way to solve the problem because model is easy to generate test scenarios and inexpensive in changing test configurations and...
The heat dissipation of six different types of microchannel networks integrated in LTCC based microsystems has been investigated by experimental measurement and simulation analysis, including straight, serpentine, spiral and fractal-shaped microchannel networks of curve, I-shaped and parallel. The cross section of microchannel is 200 ??m ?? 200 ??m and the total length is about 200 mm. The water mass...
DoS attacks bring serious threats to the Internet and the Capabilities technique is promising to defend against DoS attacks. In this paper, we firstly make profound researches on shortcomings and inadequacies of TVA (Traffic Validation Architecture), a typical Capabilities scheme based on router. And we propose ASTVA (TVA based on Autonomous Systems), which can effectively lower the cost of security...
There are two types of packet marking techniques in DDoS attacks defense. IP traceback reconstructs attack paths and entrance nodes, while path identification enables the victim identify and filter effectively malicious packets. In this paper, we propose an idea of organic combination of both that the upstream nodes identify and filter malicious packets. We specifically design a new packet marking...
In this paper, an effective approach for QRS detection is presented for wearable ECG devices in wireless Body Sensor Networks (wBSN). Significant reduction of high and low frequency noises are obtained under the action of continuous wavelet transform to original ECG signal after the careful selection of scale level. The following Hilbert transform to the transformed signal enables easier location...
Distributed Denial of Service (DDoS) attacks pose a major threat to today's cyber security. Defense against these attacks is complicated by source IP address spoofing, which is exploited by attackers to conceal source IP addresses and localities of malicious traffic. In this paper, we propose HPi (Hash-based Path Identification), a novel packet marking scheme to defeat DDoS attacks regardless of forged...
Witricity is a newly developed technique for wireless energy transfer. This paper presents a frequency adjustable witricity system to power medical sensors and implantable devices. New witricity resonators are designed for both energy transmission and reception. A prototype platform is described, including an RF power source, two resonators with new structures, and inductively coupled input and output...
On Dec 8th, 2003, the top price levels showed in the limit order book were enlarged from three to live in Chinese stock market, and the transparency was largely increased. The paper studies on the contribution of every quote price to price discovery, and compares with contribution of before and after transparency was increased. The results show that there exists significant difference of information...
With the development of three-dimensional low temperature co-fired ceramic (LTCC) packaging substrate, the internal microscale structures have great effect on the strength, toughness and lifetime of LTCC microsystem, where the study of local or nanoscale mechanical properties and microstructure is critical, especial for the prediction of the local failure behaviors. In this study, the nanoscale mechanical...
Along with the development of the electrical technology, the power of the circuit rises rapidly, heat dissipation becomes a key problem in the design of the circuit. The 3D microchannel coolers made with LTCC (low temperature co-fire ceramic) technology can absorb the heat of the chip and pass it to the external environment by the liquid circulation. In this paper, the critical manufacturing processes...
When measuring the surface of blades based on single-beam laser triangulation principle, depth of field and inclination angle of probe would bring some adverse effects to the inspection process. In order to eliminate this, an adaptive dynamic profile measuring method is proposed, which is based on the B-Spline extrapolation. Therefore, the inclination angle can be controlled by using the direction...
In adaptive observer methods for actuator fault estimation, the system has to satisfy the condition of the Strictly Positive Realness (SPR). However, some practical systems may fail to satisfy the SPR condition. This paper proposes two methods for actuator fault estimation without the need of the SPR condition, based on the adaptive observer technique with the same structure. At first, for a class...
This paper designs a kind of phase shifting algorithm of white light interferometry technology, aiming at high precision measurement of MEMS. Through analyzing the error source of phase shifting in theory, five-frame phase-shifting algorithm based on the immunity to phase-shifting error is presented. In the proposed algorithm, phase shifting distance is set to be lambda/8 per step, and the interference...
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