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Date 1-3 Dec. 2004

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Displaying Results 1 - 25 of 3665510
  • A new differential pH sensor current mode read-out circuit using two operational floating current conveyor

    Publication Year: 2004 , Page(s): S1/5 - 13-16
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (223 KB) |  | HTML iconHTML  

    This paper presents a new differential current mode read-out circuit for the ion sensitive field effect transistor (ISFET)9 as a pH sensor. It uses only two operational floating current conveyors (OFCC), and provides linear sensitivity to pH over a wide range (pH values 2-12). Moreover, it provides an output current that is linearly related to the differential current between the ISFET and the reference field effect transistor (REFET) sensors. The proposed read-out circuit uses only one type of active element (i.e. an OFCC) that makes this circuit easier to be both integrated and fabricated using a conventional CMOS process. Our simulation results demonstrate that the read-out circuit works reliably and can be a suitable sensor read-out circuit for lab on chip and biomedical applications. The read-out circuit connected with the system composed of the ISFET and REFET sensors also reduces the impact of the parameter fluctuations and environment conditions on the performance of the ISFET sensor. View full abstract»

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  • Hop-by-hop congestion control over a wireless multi-hop network

    Publication Year: 2004 , Page(s): 2548 - 2558 vol.4
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (766 KB) |  | HTML iconHTML  

    This paper focuses on congestion control over multi-hop, wireless networks. In a wireless network, an important constraint that arises is that due to the MAC (media access control) layer. Many wireless MACs use a time-division strategy for channel access, where, at any point in space, the physical channel can be accessed by a single user at each instant of time. We develop a fair hop-by-hop congestion control algorithm with the MAC constraint being imposed in the form of a channel access time constraint, using an optimization based framework. In the absence of delay, we show that this algorithm is globally stable using a Lyapunov function based approach. Next, in the presence of delay, we show that the hop-by-hop control algorithm has the property of spatial spreading. In other words, focused loads at a particular spatial location in the network get "smoothed" over space. We derive bounds on the "peak load" at a node, both with hop-by-hop control, as well as with end-to-end control, show that significant gains are achieved with the hop-by-hop scheme, and validate the analytical results with simulation. View full abstract»

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  • Modeling and simulation of FET structure for DNA sequencing applications

    Publication Year: 2004 , Page(s): S1/5 - 17-20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (231 KB) |  | HTML iconHTML  

    The paper presents an analysis of a sub-micron DNA-wire based FET. It describes the device structure, its bases of operation, introduces the device model and presents simulation results depicting internal and external device characteristics under different biasing conditions. Analyses of the simulation results as they relate to the DNA wire hybridization are discussed. The results indicate a high potential for utilizing this FET structure for DNA sequencing applications. View full abstract»

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  • A miniature, gun-hard MEMS IMU for guided projectiles, rockets and missiles

    Publication Year: 2004 , Page(s): 26 - 34
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB) |  | HTML iconHTML  

    BAE SYSTEMS is a leading provider of inertial sensors and systems, including silicon-MEMS inertial based products to automotive, commercial and military markets. BAE SYSTEMS is developing a miniature MEMS inertial measurement unit. SiIMU02™ is capable of surviving and performing after the massive shock and vibration environment of a guided projectile gun-launch event, and is small enough to fit into next generation small caliber guided rockets and missiles. This paper explains the logical progression from the first generation SiIMU01™, which is now in production, to the second generation SiIMU02™, as the next step along a development roadmap to even smaller and better performing MEMS IMUs in the near future. The IMU architecture is presented, as are results of initial prototype performance testing and gun firing trials. The emerging guided projectile and rocket programs are posing new challenges for inertial measurement units. These special requirements, and how they are solved by the unique combination of sensor technology and IMU architecture employed in SiIMU02™, are explained. View full abstract»

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  • Intelligent Web topics search using early detection and data analysis

    Publication Year: 2003 , Page(s): 584 - 589
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    Topic-specific search engines that offer users relevant topics as search results have recently been developed. However, these topic-specific search engines require intensive human efforts to build and maintain. In addition, they visit many irrelevant pages. In our project, we propose a new approach for Web topics search. First, we do early detection for "candidate topics" while extracting words from the HTML text. Secondly, we perform data analysis on the appearance information such as appearance times and places for candidate topics. By these two techniques, we can reduce candidate topics' crawling times and computing cost. Analysis of the results and the comparisons with related research will be made to demonstrate the effectiveness of our approach. View full abstract»

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  • A new sliding mode like control method for buck converter

    Publication Year: 2004 , Page(s): 3688 - 3693 Vol.5
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (415 KB) |  | HTML iconHTML  

    Sliding mode control is a robust control method with guaranteed large signal stability and good dynamic response. Despite its advantages, sliding mode control for DC-DC converters suffers from non-zero steady state error and variable switching frequency that depends on the converter parameters. This paper proposes a simple sliding mode like control (SMLC) technique for the buck converter that has a fixed switching frequency and zero steady state error. The response of this controller is robust and can be defined directly in the time domain. In addition, fuzzy logic implementation of the proposed SMLC is provided. Experimental results show that the proposed SMLC has good first-order dynamic performance and no steady state error. View full abstract»

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  • High-power InGaN light emitting diodes grown by molecular beam epitaxy

    Publication Year: 2004 , Page(s): 1299 - 1300
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (207 KB)  

    The highest power InGaN light emitting diodes produced by molecular beam epitaxy are reported. When operated in continuous-wave mode at room temperature, the optical output power of the devices was 3.75 mW at a forward injection current of 20 mA, and the maximum output power was 14.3 mW. The electroluminescence had a peak at 405 nm and a full width half maximum of 15 nm. The electrical characteristics showed a voltage of 4.8 V and a resistance of 31 Ω at a forward injection current of 20 mA. View full abstract»

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  • Using fuzzy measures to group cycles in metabolic networks

    Publication Year: 2003 , Page(s): 239 - 243
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (391 KB) |  | HTML iconHTML  

    This paper describes part of a modeling tool, called FCModeler, for exploring metabolic networks that displays and finds structural relationships in graphs. Nodes of the map represent specific biochemicals such as proteins, RNA, and small molecules, or stimuli, such as light, heat, or nutrients. Edges of the map capture regulatory and metabolic relationships found in biological systems. These relationships are established by domain experts and the biological literature. Automated cycle analysis finds sets of connected nodes in a metabolic network. Families of interconnected cycles show how metabolic cycles interact with one another. These cycle families are formed using fuzzy measure theory. View full abstract»

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  • Discovering cyber communities from the WWW

    Publication Year: 2003 , Page(s): 590 - 594
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (237 KB) |  | HTML iconHTML  

    In this paper we present a novel method to discover cyber communities from the WWW. A cyber community is a set of highly connected web pages in the WWW, which share the similar topics or interests. The WWW can be modeled as a huge scale-free network graph. Discovering cyber communities is converted to trawling the corresponding web graph to search for approximate p-quasi complete graph. The algorithm presented in this paper considers the characteristics of the scale-free network graphs and is based on the neighborhood information of the vertex in the p-quasi complete graph in the web graph. View full abstract»

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  • Modeling and analysis of perceptive robot controller based on hybrid automata

    Publication Year: 2004 , Page(s): 2924 - 2929 Vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB) |  | HTML iconHTML  

    This paper presents a modeling and analysis method for the motion planning and control of mobile robot systems in a hybrid fashion. Robotic systems obtain environmental information from perceptive sensors and respond to the perceptions to execute the task through decision and control process. The hybrid perceptive model of the robotic system has one continuous and two discrete layers, and it also has continuous and discrete perceptive references. The discrete layers enable the robot system to plan and modify original path through switching. Stability can be guaranteed in switching. The hybrid perceptive references can not be stopped by blocking the continuous reference, including obstacles. The model is verified by experiments. View full abstract»

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  • Software verification and validation within the (rational) unified process

    Publication Year: 2003 , Page(s): 216 - 220
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB) |  | HTML iconHTML  

    We discuss the integration of software verification and validation activities (as defined by the IEEE Std. 1012) within the unified process. We compare and contrast these two process frameworks, and identify the aspects of verification and validation that are directly supported, partially supported or not supported by the unified process. View full abstract»

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  • Digital loss-minimizing multimode synchronous buck converter control

    Publication Year: 2004 , Page(s): 3694 - 3699 Vol.5
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (487 KB) |  | HTML iconHTML  

    A multimode control strategy for a synchronous buck converter operating over a wide load range, is presented. For heavy loads, the converter runs in fixed-frequency continuous conduction mode (CCM). At light loads, it enters discontinuous conduction mode (DCM) with synchronous rectification. At still lighter loads, synchronous rectification is disabled in DCM. At very light loads, the converter operates in variable-frequency pulse skipping mode. The synchronous rectifier (SR) timing is scheduled as a function of the load current, enabling appropriate transition among the modes. An on-line adaptive algorithm to optimize the SR timing, based on power loss minimization, is presented. This control strategy is particularly well suited for a digital controller implementation, since it uses sophisticated computations, while not requiring high analog-to-digital conversion rates. View full abstract»

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  • Silicon pin detector with integrated JFET-based source follower

    Publication Year: 2004 , Page(s): 1301 - 1302
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    A pin photodiode monolithically integrated with a bias resistor and a JFET-based source follower is presented. Results from static and dynamic characterisation of the structure are reported, together with SPICE simulations used to design an optimised device which can be fabricated in the same technology. This structure can be employed as a pixel in linear X-ray scanners for non-destructive inspection. View full abstract»

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  • Validation of radio frequency telemetry concept in the presence of biological tissue-like stratified media

    Publication Year: 2004 , Page(s): 1335 - 1338 Vol.2
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (357 KB) |  | HTML iconHTML  

    We discuss a novel radio frequency (RF) telemetry concept for biomedical applications. The concept consists of a miniaturized spiral inductor/antenna for bio-MEMS sensors and an external pick-up antenna integrated into a hand-held device. The measured relative signal strength in the presence of biological phantoms ranged from -5.9 to -7.5 dB for antenna separations of 5 and 10 cm. These relative signal strengths are easily measurable, therefore validating the RF telemetry concept for biomedical applications. View full abstract»

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  • Dual-wavelength-pumped fiber Raman converter for wavelength conversion at 10 Gbit/s

    Publication Year: 1996 , Page(s): 156 - 157
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    Summary form only given. Optical fiber's zero-dispersion wavelength and lowest-loss wavelength depends on its physical and chemical structure, such as core and cladding materials. Wavelength conversion by stimulated Raman scattering (SRS) in fibers is known to be efficient because of its long interaction length achievable by fibers' waveguide structure. But the application of SRS to information wavelength conversion is not straightforward, because either a long propagation distance leading to temporal walk-off or a high input signal intensity leading to nonlinear phase distortion is required for efficient conversion. We propose to overcome this problem by use of dual wavelength-pumped Raman shifting method. View full abstract»

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  • A power-efficient MAC protocol for integrated voice and data services over 802.11e HCF

    Publication Year: 2004 , Page(s): 2032 - 2036 Vol.4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (650 KB) |  | HTML iconHTML  

    A novel power-efficient MAC protocol, named on-demand polling (ODP) scheme, is presented for supporting integrated voice and data services over WLAN. The ODP scheme combines the polling-based and the contention-based mechanisms over HCF (hybrid coordination function). In the ODP scheme, a voice station is in the polling list when it is in the active mode. During the idle mode, it is configured to operate in the sleep mode for saving power. Also, it adopts the contention-based mechanism to join the list again when returning from the idle mode. In this paper, we investigate the RR-Brady, the RR-CBR and the proposed ODP schemes and derive the power consumption and the aggregate throughput for voice and data stations, respectively. Simulation results show that the ODP scheme can reduce the power consumption for voice stations and enhance the throughput for data stations. View full abstract»

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  • Design of enterprise Web servers in support of instant information retrievals

    Publication Year: 2003 , Page(s): 2661 - 2666 vol.3
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (462 KB) |  | HTML iconHTML  

    As the world is building "the Internet of things", the successful deployment of instant information retrievals Web servers will be essential for enterprises to provide satisfactions for customers. For instance, the precise and pertinent information of a product should be delivered promptly and securely. By taking advantage of radio frequency identification technology, information retrievals for a product labeled with a smart tag can be performed much more efficiently than ever before. This article presents a Web server design scheme to facilitate the information retrieving in a future product identification and tracking system, aiming at meeting the following competitive requirements: responsive, evolution-prone, and locally contextual. Bucket are used for identifying product states, while binary tree search algorithms are used to sort, store, and retrieve the precise and pertinent service for a request that carries a product identity. View full abstract»

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  • A hybrid neuro-fuzzy system for neuromuscular disorders diagnosis

    Publication Year: 2004 , Page(s): S2/5 - S5-8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (182 KB) |  | HTML iconHTML  

    Motor unit action potentials (MUAPs) recorded during routine electromyography (EMG) examination provide important information for the assessment of neuromuscular disorders. The conventional computer-aid methods of MUAP diagnosis are mainly based on single feature set and single neural network model, and the diagnosis accuracy of which is not always satisfactory. In order to utilize multiple feature sets to improve diagnosis accuracy, a hybrid decision support system based on fusion multiple neural network outputs is presented. Back-propagation (BP) neural networks are used as single diagnosis models in every feature set, i.e. i) time domain measures, ii) autoregressive coefficients, and iii) cepstral coefficients. Then these outputs are combined by fuzzy integral. More excellent diagnosis yield indicates the potential of the system for neuromuscular disorders diagnosis. View full abstract»

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  • A mechanics-based strain gage methodology for solder joint reliability assessment

    Publication Year: 2004 , Page(s): 533 - 541
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1101 KB) |  | HTML iconHTML  

    It is essential to understand solder joint strains to improve package reliability. However, it is often difficult to measure the true solder joint strains directly. Strain gages have been increasingly used to indicate package mechanical stress levels. One of the most used strain gage locations is on the component side, right next to the package corner. A concern with this location alone is that the strain gages mounted close to the package pick up the local stress concentration near the package edges or corners. In this paper, appropriate strain gage locations are suggested based on mechanics principles and finite element simulation results. The solder joint deformations are determined from strain gage readings at various locations. This paper also proposes a new strain matching criterion. Most original equipment manufacturers (OEMs) have been using maximum principal strain to match stress levels and define strain limits. A problem with maximum principal strain is that it does not indicate the direction along which the maximum bending occurs. Experimental data demonstrates that the new strain criterion has much better correlation to solder joint failure than maximum principal strains in various bend modes. The conclusions apply to any strain gage mounting metrology on packages attached to printed circuit boards (PCBs). View full abstract»

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  • Internet-based decision support: towards e-hospital

    Publication Year: 2003 , Page(s): 595 - 600
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (802 KB) |  | HTML iconHTML  

    Rapid progress in information technology enables us to retrieve relevant information from databases on the internet. Medical and health care are not exceptions: the recent advances provide a new environment to telemedicine, in which online information retrieval has been challenging problems. In this paper, a new approach to internet-based decision support from university hospital is presented. The system consists of the following four components: one is a web-based system for home doctors, which supports writing an introduction letter to the university hospital. Second one gives a diagnostic and therapeutic report on the patient who was introduced by home doctors and admitted to the university hospital. Third system gives reports on medical images and pathological examinations. Finally, the fourth one makes a decision support for neurological diseases. The integrated system has been already in use at Shimane University Hospital since 2001 and is now being evaluated by doctors inside/outside the hospital. View full abstract»

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  • Motion planning of robot fingertips for graspless manipulation

    Publication Year: 2004 , Page(s): 2951 - 2956 Vol.3
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (533 KB) |  | HTML iconHTML  

    In this paper, we present a method of motion planning of multiple robot fingertips for graspless (or nonprehensile) manipulation. The method can automatically generate various graspless operations, including pushing and tumbling. By considering whether each robot finger should be position- or force-controlled, we can obtain robust manipulation plans against external disturbances. Some examples of planned graspless manipulation of a cuboid by two robot fingers are presented. We also show an experimental result of execution of planned graspless manipulation by a robot with a multi-fingered hand. View full abstract»

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  • Driving innovation in the electricity sector

    Publication Year: 2005 , Page(s): 2,2/1 - 2,211
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (213 KB)  

    This paper discusses the driving innovation in the electricity sectors. Technology has impact along the E-value chain and reshapes the energy markets. Technology add values both in supply-side and demand-side. Technologies can also create changes and chances in market operation and customer behaviour. View full abstract»

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  • High capacity image steganography using wavelet-based fusion

    Publication Year: 2004 , Page(s): 430 - 435 Vol.1
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (639 KB) |  | HTML iconHTML  

    Digital steganography exploits the use of a host data to hide a piece of information in such a way that it is imperceptible to a human observer. This work presents a cover-screw algorithm based on what is called the wavelet based fusion. In this method the wavelet decomposition of both the cover image and the secret message are merged into a single fused result using an embedding strength factor ( ). The algorithm also applies a preprocessing step on the cover image to shrink the range of the pixels components in order to guarantee that the embedded message will be recovered with acceptable accuracy. Experimental results showed the high invisibility of the proposed model as well as the large hiding capacity it provides. View full abstract»

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  • An on-line hot-spot detection scheme in DS-CDMA networks - single traffic type

    Publication Year: 2004 , Page(s): 3911 - 3915 Vol.6
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB) |  | HTML iconHTML  

    The intensive handoff calls from surrounding cells, triggered by non-uniform traffic distribution, cause more serious quality of service (QoS) deterioration problems than uniform traffic distribution because they usually cannot be regulated by admission control. This paper proposes an on-line hot-spot detection scheme, which predicts the presence of hot-spots and assists the admission control to reduce the handoff deterioration probability. Our proposed scheme consists of two procedures: 1) a utilization trend detection procedure, which predicts the traffic load of the desired sector from its past utilization information; and 2) an aggregated utilization procedure, which estimates how close is the desired sector to the hot-spot regime. Simulations show that under an acceptable new call blocking probability, the proposed scheme decreases the handoff deteriorating probability of the hot-spot cells and their surrounding cells. View full abstract»

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  • Learning spatial context from tracking using penalised likelihoods

    Publication Year: 2004 , Page(s): 138 - 141 Vol.4
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (709 KB) |  | HTML iconHTML  

    MAP estimation of Gaussian mixtures through maximisation of penalised likelihoods was used to learn models of spatial context. This enabled prior beliefs about the scale, orientation and elongation of semantic regions to be encoded, encouraging one-to-one correspondences between mixture components and these regions. In conjunction with minimum description length this enabled automatic learning of inactivity zones and entry zones from track data in a supportive home environment. View full abstract»

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