Search

The digital low-dropout (D-LDO) regulator can work effectively in low supply voltage. It is appropriate for the digital circuits due to great process scalability. However, D-LDOs suffer a poor transient response caused by the limited sampling clock and the logic delays. Therefore, the transient performance needs to be improved. One of the solutions is getting rid of the control scheme related to synchronous clock. This paper presents an enhanced analog assisted (E-AA) technique for D-LDOs to reduce the voltage spikes. The proposed technique adds a current buffer (CB) and a switch compensated resistor (SCR) into the conventional passive analog assisted loop. The CB is used to amplify the loop gain. The SCR is used to prevent a second droop of output voltage during recovery. The simulation results show that a maximum voltage undershoot is 16.4 mV with a 5 mA/3.8 ns load step and a total capacitor is only 52 pF. Thus, the resulting figure-of-merit (FoM) is 0.41 ps.

A novel CMOS bipolar Gaussian monocycle pulse generator consisting of single to differential circuit, narrow pulse generator and Gaussian pulse-shaping circuit is presented. Without traditional LC filtering or multi-channel pulses combination, the proposed generator can be low power and low complexity. Fabricated in a 180 nm standard CMOS process, the test results show that the bipolar Gaussian monocycle pulse can be generated correctly, the power consumption is 1 mW at 200 MHz pulse repeating frequency and the chip core area is only 0.08 mm 2 under the power supply of 1.8 V, demonstrating the proposed generator with the advantages of low power and low complexity is suitable for implantable IR-UWB transmitter.

Virtual reality provides a new means for sensing and displaying Building Information Modeling (BIM) from two-dimension to three-dimension. This work uses virtual reality technology to connect BIM models with human perception based on the modeling and integration of BIM models. A variety of virtual reality methods are provided to perceive the highway BIM, such as holographic imaging, panoramic publishing, 3D printing, virtual driving, virtual flight, virtual cycling, virtual walking, augmented reality construction model delivery, etc. Virtual reality realizes people-oriented evaluation and optimization for highway project design, and improves the scientific nature of highway planning and design.

In this paper, a novel design on AC LED driver with no current glitch for multiple-string LEDs is presented. The LED driver can run LEDs directly from a pulsating voltage obtained by rectifying an AC voltage without any other AC-DC converter. In order to avoid current glitch due to hard switching operation, negative feedback control is used and the driver operates on a soft switching mode. Without AC-DC converter and complicated control circuit, the driving system is suitable for integration and the driver can be designed on a simple chip. Simulation results show that the lifespan is prolonged, and the quality of lighting and the efficiency of the system are improved because of no more current glitch. The proposed AC LED driver was fabricated in 1 um SPDM 5V40V700V BCD process. The measured results show that the efficiency is about 91% and the power factor is 98.5% under 3.3W 220V∼50Hz condition.

Image-based 3D reconstruction is not only useful for reconstructing visually realistic 3D flames, but it also deepens our understanding of flame physical nature. In this paper, we focus on the capturing and reusing of 3D temperature fields. A novel method is proposed to reconstruct and edit 3D temperature filed for combustion flame. Firstly, a multi-view imaging system is designed to capture the color images of combustion flames. Secondly, the 3D temperature distributions are calculated by using irradiance attenuation calibration, tomographic reconstruction and two-color pyrometric techniques. Finally, a target temperature driven editing method is proposed to restore the dynamic information between the reconstructed temperature fields, and to control flame animation based on temperature field directly. The experimental results indicate that our approach performs well in temperature field capturing and reusing.

Middleware, operating systems, and databases have been developed to the point where they have become fundamental components in the modern software era. The JTang middleware platform was developed for the modern service industry, and it offers a range of basic techniques, methods, middleware software, and tools for the services computing technology. This chapter describes the background for the development of this platform and its main components.

Service-based systems are facing great uncertainty due to the dynamic internet environment. Service verification and reconfiguration are used as the main mechanisms to improve the robustness of service-based system. This chapter first gives an overview of service verification and dynamic reconfiguration. Then it introduces an approach to verify the substitutability between different granularity services. Finally, it presents a quality of service-driven dynamic reconfiguration method.

Today, web service, due to its open standards, has been used extensively to build distributed applications. Because web services can be reused and composed to fulfill a complex request, the issue of web service composition has grown to be a hot topic and has attracted many researchers to work on it. This chapter first gives an overview of the area of service composition and addresses new challenges on service composition. Then it introduces three service composition methods.

A simple silicon two-dimensional (2D) flow sensor for the measurement of both flow direction and speed is described. By integrating two couples of silicon spreading-resistance temperature (SRT) sensors in two perpendicular directions on the surface of a silicon chip, this sensor can detect flow speed and flow direction φ in a full range of 360°. Experimental results confirm theoretical analysis that the output of the sensor increases with the square root of the flow velocity, and the outputs in the two perpendicular directions are proportional to sin φ and cos φ, respectively. The effects of sensor layout are also discussed. With complete oxide isolation for the SRT sensors, the flow sensor could achieve higher sensitivity by operating above the intrinsic temperature of silicon (∼150 °C), or could be used to detect fluid flow at a temperature as high as 300 °C.

Recently, the emerging accumulation of biomedical data on the Web (e.g. vast amounts of protein sequences, genes, gene products, drugs, diseases and chemical compounds, etc.) has shaped a big network of isolated professional knowledge. Embedded with domain knowledge from different disciplines all regarding to human biological systems, the decentralized data repositories are implicitly connected by human expert knowledge. Lots of biomedical data sources are published separately in the form of semantic ontologies represented by Web Ontology Language (OWL) syntax, which is naturally based on linked graphs. When we are faced with such massive, disparate and interlinked data, biomedical data analysis becomes a challenge. In this paper, we present a general OWL reasoning framework for the analysis of big biomedical data and implement a MapReduce-based property chain reasoning prototype system. OWL reasoning method is ideally suitable for problems involved complex semantic associations because it is able to infer logical consequences based on a set of asserted rules or axioms. MapReduce framework is used to solve the problem of scalability. In our experiment, we focus on the discovery of associations between Traditional Chinese Medicine (TCM) and Western Medicine (WM). The results show the system achieves high performance, accuracy and scalability.

This paper puts forward a kind of novel methodology for software system development, from the point of view of the problem existed in software development -- the gap between the requirement specification level and the program implementation level. We attempt to begin from the specification level of software development to touch the process of high-level specification construction profoundly. We propose a specification language to support multiple semantic dimensions and based on which build a unified functional model of software system in a specific domain. On the bases of these, we apply transformation and refinement methods to the model and transit it from the specification level to the implementation level. We expect such a process can change the current software producing procedure in nature. We also put this methodology into the application of the software development in real-time serving domain we focus on, which turns out to be encouraging.

In the Internet computing environment, clients usually invoke remote components to accomplish computation. As a result, many security problems are raised. Traditional network component architecture model focuses on business logic. It takes into little consideration the security problems when business logic is invoked. This paper proposes secure network component architecture model (SNCAM) to address them. It classifies clients according to their credibility levels on the component side. Next, we discuss the main idea of this paper, which is the security domain. To reduce the overhead introduced by the security mechanisms, a method called security agent is proposed. Finally, it quantitatively determines the performance cost introduced by the security mechanisms, and when to use the security agent

This paper describes a novel approach which combines the acoustic analysis using MFCC and the speaker's mean pitch to improve the performance of the gender recognition. In acoustic analysis, two sets of Gaussian mixture model (GMM), male and female, are trained from the speech, and the most likely sequence of models with corresponding likelihood scores are produced. In pitch estimation approach, a threshold is specified to differentiate the two sets. The information provided by the acoustic analysis using MFCC and pitch estimation are combined by using a linear normalization fusion method. The system was tested on the SRMC databases giving at most 3.3% recognition error rate

AlphaOS is a newly born RTOS for automotive use. It is compliant with OSEK/VDX standard and has a high performance compared to the average. This creation is conceived at July 2002, implemented on Motorola MPC555 board at November 2003 and fully tested till May 2004. This paper focuses on the design architecture and the test "method flow" of AlphaOS, aiming at revealing the methodology of how to develop and test an OSEK compliant RTOS.

The efficiency of the services discovery in Internet is attracting increasing attention. To compare with popular services discovery mechanism (UDDI mainly), we propose an agent-based services discovery mechanism in Internet (ABSDM). In this mechanism, we suppose that services information documents are stored in distributed servers, and servers are regarded as independent agents. So a searching-tree creating algorithm (STCA) could be used to join servers into a tree structure. Based on this structure, a recursive searching algorithm could be used to distribute searching request over the whole tree. During above-mentioned process, searching request could be parallel dealt with. Furthermore, searching efficiency of UDDI and ABSDM is evaluated and compared theoretically.

Wireless sensor networks (WSNs) are an area of emerging networking research. One obstacle is its limited supply of energy. Therefore, minimizing energy consumption and maximizing system lifetime have been a major design goal for WSNs. This paper presents an energy-efficient event-driven clustering routing algorithm (EDC algorithm) based on unique features of the event-driven data model of WSNs. The algorithm can decide which nodes would become cluster-head nodes according to the maximum remainder energy of nodes, which are sensing an event occurred and are firstly switched to the active state if their several components are in the sleeping state. This strategy can keep sensor nodes with lower remainder energy out of being used up quickly. Detailed simulations of sensor network environments demonstrate that EDC algorithm saves node energy, prolongs system lifetime, and improves evenness of dissipated network energy.

The time management is a crucial issue in the service-based, loose-coupled workflows. This work presents a time model for service-based workflows. In this model a service is divided into two parts, public part and private part. Then in this way time management in service-based workflows can be simplified. On the other hand, it preserves the autonomy of the workflow services.

An interorganizational workflow management system is an efficient tool to manage processes which cross organizational boundaries. This paper proposes a mobile-agent based interorganizational workflow management system. In the system, processes are executed by mobile agents that consist of both definitions and instances of processes and move among relevant organizations. Both the model and structure of the system are given here and an example is used to illustrate the general procedure of the execution of interorganizational processes in the system.

Smart sensors are sensing nodes that contain local intelligence to receive commands and take actions. They act as feelers of ubiquitous computing environments. Their software platform has to meet the requirements of concurrent operations, real-time constraint, adaptability and dependability. Gamma-OS is an OS kernel designed for these smart devices. This work analyzes the typical task model of smart sensors and presents the implementation of scheduling, resource access and dynamic admission control schemes in gamma-OS. Its primary and subordinate two-level task-scheduling scheme can efficiently isolate the scheduling of time-critical and time-uncritical tasks. Fault tolerance strategies including FTRMS admission control, fault detection, and fault recovery are also extended in gamma-OS to tolerate transient faults in executions of tasks.

Temporal behaviors prediction is very critical for real-time control systems. This paper presents a method to analyse the worst-case response time of OSEK/VDX compliant hard real-time distributed control systems. OSEK/VDX is an industry standard for an open-ended architecture for distributed control units in vehicles. Traditional time analysis methods based on the fixed priority preemptive scheduling model do not account for the problems occur in practical systems. Based on the current time analysis technologies, we propose an accurate time analysis method considering the practical effects of resource access synchronization, mixed preemptive and non-preemptive scheduling, as well as the overheads of OSEK OS. Furthermore, we also propose a scheme to efficiently integrate time analysis tools into the current development process for electronic control units in vehicles

Wireless sensor networks (for short, WSNs) can be used in many aspects in the future. One obstacle is their limited supply of energy. Therefore, minimizing energy consumption and maximizing the system lifetime have been major design goals for WSNs. This paper presents an energy-efficient ACHGT (Adaptive Clustering Hierarchy based on Game-theoretic Techniques) routing algorithm for WSNs. Individual sensors of the algorithm are modeled as players to make decisions about whether electing to become cluster-head nodes by using node energy payoff functions to weigh their own costs and benefits. This strategy can keep sensor nodes of lower remainder energy out from being used up quickly. Besides, it can evenly distribute the energy load among the sensors in the network to prolong system lifetime. Detailed simulations of sensor network environments demonstrate that the ACHGT algorithm reduces energy consumption, and improves the evenness of dissipated network energy and the ability to postpone the network partitions.

This paper is to elaborate the importance and necessity of applying knowledge management (KM) in intelligent transportation systems (ITS). The paper also discusses the possible target market, the application ranges of KM in ITS, the main contents and the primary methods of KM in ITS. A typical model of KM in ITS are given to elucidate the three layers of KM platform in ITS. Finally, the paper expresses the prospective future of applying KM in ITS.

Smart sensors differ from conventional ones in their ability to process a high amount of data close to the source and in the ability to communicate in a bidirectional way. In this article, we show the reasons to make sensors smart, identify the design challenges of the software running on smart sensors, and put forth our software platform. In our solution, we adopt the event-driven components with bidirectional interface and provide alternative scheduling policies for specific applications. This component infrastructure also supports diversity of connections by including a hierarchical communication model. Additionally, we present our solutions to improve the reliability of these software systems.

In a speaker identification system, training speaker models (e.g. Gaussian mixture model, GMM) is computationally expensive, especially when the dimension of feature vectors is large. Principal component analysis (PCA) method is an optimal linear dimension reduction technique in the mean-square sense, which can reduce the computational overhead of the subsequent processing stages. In this paper, a new speaker identification framework is proposed, with PCA embedded in after feature extraction step. Experiments are conducted to investigate PCA de-correlation and dimension reduction properties. The robust ability of PCA transform is also examined. Some promising results are found.

Software architecture based on remote components was a component based framework to rearrange the invoking order of local function and remote component for parallel running. This paper presents a construct concurrent code algorithm for software architectures based on remote components. Using the formal description of the algorithm, it impacts upon the system performance are studied in detail. The experiment results showed that algorithm scheme method that can greatly improve system performance. The concurrent algorithm provides a cooperating method of local framework and remote service for distributed software architecture.

A new classification using support vectors is presented. Support vector machines that learn classification problem are specific to use hyperplane. We propose a novel approach that contains support vectors describing the hypersphere to separate the samples. We also generalize it in multi-class classification phrase. The experiment results on UCI datasets are presented.

A novel approach to speaker recognition is presented. The method, called Support Vector Data Description (SVDD), was originally suggested by Vapnik, interpreted as a novelty detector by D. Tax and R. Duin (1999). In this paper, we use this data domain description as a classifier. It contains support vectors describing the sphere separating the samples. With a minimal radius R, this classifier achieves good performance in finding abnormal samples within the open set test. We use it in the speaker identification application. The results on YOHO database are presented.

A new BPSK demodulator was presented. By using a clock multiplier with very simple circuit structure to replace the analog multiplier in the traditional BPSK demodulator, the circuit structure of the demodulator became simpler and hence its power consumption became lower. Simpler structure and lower power will make the designed demodulator more suitable for use in an internal single chip design for a wireless implantable neural recording system. The proposed BPSK demodulator was implemented by Global Foundries 0.35 μm CMOS technology with a 3.3 V power supply. The designed chip area is only 0.07 mm2 and the power consumption is 0.5 mW. The test results show that it can work correctly.

Dealing with changes in processes has become unavoidable in deploying workflow. To improve the ability of workflow management in dealing with changes has emerged as a hot research topic in the area of workflow management. According to the changeable characteristics, workflow processes are categorized into dynamic, adaptive and flexible processes. In this paper, we primarily deal with the flexible processes. Flexibility is the ability of workflow process to execute on the basis of a loosely, or partially specified model, where the full specification of the model is made at runtime, and may be unique to each instance. To provide full support for flexibility, we propose a simple but applicable flexible workflow model based on ECA rules and composition of activities at runtime. Furthermore, selection constraints and composition constraints are put forward to ensure the valid selection and composition of activities at runtime. We also design two algorithms, one is to automate the composition with the best concurrence which is defined as the ability of activities to be executed in parallel and the other is to verify the validness of the manual selection and composition.