Analysis and design of CW-LD pumped stable Q-switched laser

A high power continuous wave (CW) laser diode (LD) pumped acousto-optic Q-switched Nd:YVO4 laser is presented. A short pulse at the 1064 nm is obtained. With a repetition rate of 50 kHz, the maximum average output power of 5.72 W is achieved. The optical conversion efficiency and the slope efficiency are up to 28% and 32.4% respectively. At the repetition rate of 10 kHz and the pulse width of 16.3ns, the maximum single pulse energy of 286 μJ and the peak power of 13kW are acquired. The laser can be used as a signal source in the free-space optical communication. The output signal agrees with the modulate signal well.     

High-temperature characterisation and analysis of leakage-current-compensated,low-power bandgap temperature sensors

This paper presents a low-power, high-performance current-feedback instrumentation amplifier (CFIA) for portable bio-potential sensing applications. Noise analysis is performed to assign an optimized current for the input stage of the amplifier. Analysis on selecting nested chopping frequencies is performed, further reducing 1/f noise and the residual offset. Enhanced power efficiency is achieved by sharing cascode branches and using a Class-AB output stage. Through these methods, a good balance between noise performance and other parameters such as output ripples and power consumption of the ripple reduction feedback loop (RRFL) is achieved. The amplifier is developed using a 1-poly 6-metal 0.18 μm CMOS process. Three gain stages with a gain-boosting input stage provide a low-frequency, open-loop gain >250 dB. When configured to a closed-loop gain of 60 dB, the amplifier achieves a noise voltage density of 18 \({\text{nV}}/\sqrt {{\text{H}}z}\) and a 1/f noise corner of 3 Hz. With a current of 75 μA and a supply voltage of 3.3 V, a CMRR of 110 dB and a PSRR of 120 dB are achieved, with an average input offset of about 6.5 μV. The amplifier achieves a state-of-art noise efficiency factor of 4.2. Practical application of the CFIA is demonstrated with an in vivo electrocardiogram detection.     

Design-to-testing: a low-power, 1.25 GHz,single-bit single-loop continuous-time $$\Delta \Sigma$$ modulator with 15 MHz bandwidth and 60 dB dynamic range

Continuous-time Delta-Sigma (CT-\(\Delta \Sigma\)) analog-to-digital converters have been extensively investigated for their use in wireless receivers to achieve conversion bandwidths >15 MHz and higher resolution of 10–14 bits. This paper presents the complete design-to-testing tutorial of a state-of-the-art high-speed single-bit CT-\(\Delta \Sigma\) architecture and its circuit design details in 0.13 μm CMOS technology node sampling at 1.25 GS/s. The designed modulator achieves higher dynamic range of 60 dB in a wide conversion bandwidth of 15 MHz and consumes only 3.5 mW. The proposed modulator achieves a Figure of Merit of 154 fJ/level.     

An efficient framework for dynamic reconfiguration of instruction-set customization

We present an efficient framework for dynamic reconfiguration of application-specific custom instructions. A key component of this framework is an iterative algorithm for temporal and spatial partitioning of the loop kernels. Our algorithm maximizes the performance gain of an application while taking into consideration the dynamic reconfiguration cost. It selects the appropriate custom instructions for the loops and clubs them into one or more configurations. We model the temporal partitioning problem as a k-way graph partitioning problem. A dynamic programming based solution is used for the spatial partitioning. Comprehensive experimental results indicate that our iterative partitioning algorithm is highly scalable while producing optimal or near-optimal (99% of the optimal) performance gain.     

Structural and Energetic Analysis of Group V Impurities in p-Type HgCdTe: The Case of As and Sb

Although molecular beam epitaxy technology-based arsenic-doped Hg_1?x Cd _x Te has been extensively studied, according to the newly proposed framework of the defect-complex-based p-type doping mechanism, heavier group V elements such as antimony (Sb) should have a different doping behavior because of their larger radius which can cause larger lattice distortion. In this work, we performed first-principles calculations and took As and Sb as examples to study this issue. The substitutional doping, interstitial doping (including split, tetrahedral, and hexagonal interstitial sites), and defect complex doping forms for arsenic and antimony are all investigated. A significant lattice distortion is found in hexagonal and split-site interstitial-Sb-doped Hg_0.75Cd_0.25Te due to the larger covalent radius of Sb. Compared with As, Sb can lead to a more complicated configuration change in the case of Sb_Hg-V _Hg-Sb_Hg tridoping, and the interstitial Sb is found to be stable even with the coupling of Hg vacancies through detailed energetic calculations, indicating that the interstitial Sb has greater ability to form stable defect complexes, and thus great potential to be a more appropriate p-type dopant. This study provides more complementary understanding of the behaviors of group V impurities in HgCdTe.     

Authenticated Encryption: Relations among Notions and Analysis of the Generic Composition Paradigm

An authenticated encryption scheme is a symmetric encryption scheme whose goal is to provide both privacy and integrity. We consider two possible notions of authenticity for such schemes, namely integrity of plaintexts and integrity of ciphertexts, and relate them, when coupled with IND-CPA (indistinguishability under chosen-plaintext attack), to the standard notions of privacy IND-CCA and NM-CPA (indistinguishability under chosen-ciphertext attack and nonmalleability under chosen-plaintext attack) by presenting implications and separations between all notions considered. We then analyze the security of authenticated encryption schemes designed by “generic composition,” meaning making black-box use of a given symmetric encryption scheme and a given MAC. Three composition methods are considered, namely Encrypt-and-MAC, MAC-then-encrypt, and Encrypt-then-MAC. For each of these and for each notion of security, we indicate whether or not the resulting scheme meets the notion in question assuming that the given symmetric encryption scheme is secure against chosen-plaintext attack and the given MAC is unforgeable under chosen-message attack. We provide proofs for the cases where the answer is “yes” and counter-examples for the cases where the answer is “no.” M. Bellare’s work was supported in part by a 1996 Packard Foundation Fellowship in Science and Engineering, NSF CAREER Award CCR-9624439, NSF grants CNS-0524765 and CNS-0627779, and a gift from Intel Corporation. C. Namprempre’s work was supported in part by grants of the first author and the Thailand Research Fund.     

Leakage current,active power,and delay analysis of dynamic dual Vt CMOS circuits under P–V–T fluctuations

The leakage current, active power and delay characterizations of the dynamic dual V_t CMOS circuits in the presence of process, voltage, and temperature (P–V–T) fluctuations are analyzed based on multiple-parameter Monte Carlo method. It is demonstrated that failing to account for P–V–T fluctuations can result in significant reliability problems and inaccuracy in transistor-level performance estimation. It also indicates that under significant P–V–T fluctuations, dual V_t technique (DVT) is still highly effective to reduce the leakage current and active power for dynamic CMOS circuits, but it induces speed penalty. At last, the robustness of different dynamic CMOS circuits with DVT against the P–V–T fluctuations is discussed in detail.     

A novel design of ultra-broadband,high-gain and high-linearity variable gain distributed amplifier in 0.13 μm CMOS technology

A high-gain, high-linearity and ultra-broadband variable gain distributed amplifier (VGDA) based on employing multiple techniques is presented to substantially increase the gain. The complete design is composed of two major parts including a VGDA part followed by a single stage distributed amplifier (SSDA) part. The VGDA part makes it possible to achieve different gain settings. For high gain considerations, the SSDA part cascades with the VGDA part that takes the benefits of the multiplicative gain mechanism. A theory is presented to enhance the linearity without imposing further DC power consumption. This idea has been validated by simulation results as expected. The design is analysed and simulated in the standard 0.13 μm CMOS technology. It presents the large gain tuning range of 35 dB, from –5 dB attenuation gain up to +30 dB maximum amplification gain, in relation to the control voltage (V_ctr) that varies between 0.42 and 1.1 V. At the maximum amplification gain setting, it presents a DC up to 16 GHz 3 dB bandwidth, an average noise figure of 3.2 dB and an IIP3 of –2 dB m. Furthermore, it dissipates 46.42 mW from 0.7 and 0.9 V power supplies of the drain lines of VGDA and SSDA parts, respectively. Additionally, the Monte Carlo (MC) simulation has been performed to predict an estimate of the accuracy of performance of the proposed design under various conditions.     

Cryptanalysis of block-wise stream ciphers suitable for the protection of multimedia and ubiquitous systems

In this paper we introduce a general framework of related-key attack on block-wise stream ciphers which are suitable for the protection of multimedia and ubiquitous systems. As a case study, we show how our cryptanalytic framework is applied to a block-wise stream cipher TWOPRIME: we construct various related-key differentials of TWOPRIME and use them to show that recovering related keys of TWOPRIME can be performed with a data complexity of 2¹⁴ known plaintext blocks and a time complexity of 2³² 8-bit table lookups. We expect that our general framework for a related-key attack would be useful tool for analyzing many of block-wise stream ciphers.     

Design and Analysis of Ring Resonator with Thermal Tuning

A type of waveguide ring resonator, based on Er^3＋/Yb^3＋ co-doped phosphate glass and using thermal-optical effect as tuning manner, is brought up. The ring resonator is composed of two straight waveguides and a ring waveguide with radius of 400 μm. Electrode is evaporated on the top of the waveguide to achieve thermal tuning. Firstly, the filtering scheme of the ring resonator is analyzed, then how parameters of the electrode influence the filtering characteristics is discussed.     

Analysis and Implementation of Dual-ZCS forward DC/DC Converter

As the switching frequency of switch mode power supply (SMPS) increases, the original working mode, such as pulse width modulate (PWM) is not compatible. So, many researches start to investigate new soft switching technic[1~3]. Soft switches not only have the advantages of lower switching loss, higher working frequencies and smaller volume, but also introduce little electromagnetic interference than hard switches. The combination of dual-switch forward topology and soft switch technology ca…     

Analysis of Phased-Mission System Reliability and Importance with Imperfect Coverage

Accounting for static phased-mission systems (PMS) and imperfect coverage (IPC),generalized and integrated algorithm (GPMS-CPR) implemented a synthesis of several approaches into a single methodology whose advantages were in the low computational complexity, broad applicability,and easy implementation. The approach is extended into analysis of each phase in the whole mission.Based on Fussell-Vesely importance measure, a simple and efficient importance measure is presented to analyze component‘s importance of phased-mission systems considering imperfect coverage.     

Analysis and Implementation of DuaI-ZCS forward DC／DC Converter

As the switching frequency in DC/DC converter increases, original ‘hard-switch’working mode is not compatible. Another problem is the reliability, which is puzzled in single-ended forward, push-pull or bridge-like structures. In this paper, a new dual-ZCS (zero current switches)forward topology is proposed. The operating principle of soft-switch is analyzed, showing the relationship between voltage and current in time domain. Then how to calculate the key parameters of resonant network is. Finally, a prototype ZCS SMPS is implemented and tested. The results consisted with the analyzing results well, and illustrated the advantages of the proposed structure.     

Role Models — Patterns of Agent System Analysis and Design

Due to their autonomy and social behaviour, agents will play important roles in emerging enterprises; they will fill key positions and provide essential capabilities. This paper describes role modelling as a software engineering technique for specifying, analysing, and designing systems on the basis of the roles that the agents will play. This paper builds on our earlier research in patterns of agent systems. A pattern is a useful solution to a reoccurring problem in a particular context; patterns can be used to solve software engineering problems in analysis, design, and implementation. This paper explains how object-oriented role models can be extended to represent patterns of agent interaction that can then be employed to engineer agent systems. Role theory deals with collaboration and co-ordination. Roles have also been applied to distributed systems management, and to agent and robot systems. However, there has to date not been a methodology for realising these representations in an automated or semi-automated system, due to the lack of adequate formalism and corresponding abstractions in software. Role models rectify this situation for software analysis, design, and implementation.     

The hop count shift problem and its impacts on protocol design in wireless ad hoc networks

The hop count information has been exploited in the design of networking protocols in wireless ad hoc multi-hop networks. The hop count setup process normally assumes a perfect disk communication model and uses a simple controlled flooding approach. However, the practical communication model may not be such a disk communication model but time-varying and lossy. Sometimes transmissions can be successful beyond the nominal transmission range, i.e., the radius of such a disk model. The defacto hop count which are setup via time-varying and lossy radio channels may be different from the one based on the disk communication model. This paper introduces the hop count shift problem in realistic radio channels and investigates its impacts, via extensive simulations, on some representative hop count based protocols. Our simulation results suggest that these protocols’ performance generally suffers from the hop count shift problem, and the degradation is dependent on how the practical communication model deviates from the disk communication model. We also propose a strategy to combat the hop count shift problem and conduct simulations to show its effectiveness. The study of this paper necessitates reexaminations for the design of new hop count setup mechanism and the hop count based networking protocols.     

Stability and H ∞ Performance Analysis of Switched Stochastic Neutral Systems

This paper is concerned with the problems of stability and H _∞ performance for a class of switched stochastic neutral delay systems. By applying the average dwell time method, sufficient condition is first derived to guarantee the mean-square exponential stability of the switched stochastic neutral system. Then, the condition on a weighted H _∞ performance is proposed. The corresponding results are all formulated in terms of linear matrix inequalities (LMIs). Finally, a numerical example is provided to illustrate the effectiveness of the proposed approach.     

Analysis of Intermediate Product Price and Social Welfare in the Vertical Merger of Enterprises

With the development of modern economy, the merger of enterprises is not only the important growth method of the enterprise, but also the strategic tool with which a nation may adjust the industrial structure and guarantee its social welfare. Used as a kind of enterprise’s market behavior, the enterprise merger plays a key role in extending the scale of enterprise, increasing the property effectively and improving the economic performance. The merger of enterprise is divided into horizontal m…     

Performance Analysis of Tags Collection Time on A New Architecture of 2.4 GHz Embedded Active RFID System for Indoor and Outdoor Tracking and Monitoring Applications Based on IEEE 802.15.4 Standard

This paper focuses on the analysis of tags collection time of 2.4 GHz embedded active Radio Frequency Identification (RFID) system for indoor and outdoor real-time tracking and monitoring applications based on IEEE 802.15.4 standard. The main novelty of the system is the implementation of the communication method in order to provide Machine to Machine (M2M) communication and automated switching mechanism between indoor and outdoor location by utilizing active RFID, Wireless Sensor Network (WSN), Global Positioning System (GPS) and mobile communication on a single platform. In this work, GPS receiver covers outdoor location tracking, while active RFID provides identification and Receive Signal Strength Indicator (RSSI) reading for each tag holder to cover indoor location tracking especially near or inside building where location information is not detected by GPS. Several experiments were conducted on three different RFID tags which were active RFID tag embedded with GPS and GSM (ERFIDG2), active RFID tag embedded with GPS (ERFIDG) and standalone RFID tag communicating with the same active RFID reader. The experiment was done to evaluate the communication performance of the active RFID in terms of tags collection time using Transparent (AT) and Application Programming Interface (API) mode. The experiment was extended to measure tags collection time in single hop and multi hops communication for Tag Talk First (TTF) and Reader Talk First (RTF) protocols. The results show that the proposed active RFID system (ERFIDG2) is better than the standalone and ERFIDG systems. The in-depth research done in this work is to study the experience and identify the challenges that will be faced in the development and implementation of a wireless RFID-based system for tracking and monitoring applications.