Errors that arise from tolerance variations and mismatches between devices severely degrade the performance of bandgap reference circuits, which are essential building blocks to all high-performance systems. All these...
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Errors that arise from tolerance variations and mismatches between devices severely degrade the performance of bandgap reference circuits, which are essential building blocks to all high-performance systems. All these error sources have been analyzed (and verified through SPICE) and their design implications have been addressed. It has been found that resistor tolerance and current-mirror mismatch are the dominant sources of error in bandgap reference-type circuits. Further, it has been found that resistor mismatch, transistor mismatch, and current-mirror mismatch errors have a PTAT variation, while resistor tolerance error has a CTAT dependence - both PTAT and CTAT errors are eliminated by trimming the PTAT terminating resistor in a bandgap circuit, only at room temperature. Resistor TC errors cannot be trimmed out and hence resistors must therefore be carefully selec.ed and designed.
A quartz crystal microbalance (QCM) has been used to monitor the polymer production of a bacterial population in liquid medium. The increasing amount of produced polymer corresponds to an increase in the viscosity of ...
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A quartz crystal microbalance (QCM) has been used to monitor the polymer production of a bacterial population in liquid medium. The increasing amount of produced polymer corresponds to an increase in the viscosity of the liquid, which is directly measurable as the fluid contacts the surface of the quartz crystal in the sensor system. This procedure is being developed as a novel method for measuring microbial polymer production and growth of an environmental isolate obtained from a river sediment contaminated with petroleum hydrocarbons. This measurement technique may be used to monitor growth characteristics of unknown anaerobic bacteria when used in conjunction with other currently employed microbiological test methods such as spectrophotometry to measure turbidity. In the presence of glucose, a novel, strictly anaerobic bacterial isolate, designated strain JEL-1, produces a viscous, as yet unidentified polymer. In defined minimal media containing amino acids and glucose under a nitrogen gas atmosphere, copious quantities of this polymer are produced. This research investigates the corresponding increase in quantity of the polymer produced by JEL-1 as well as the polymer production rate in a controlled liquid medium.
In this paper, we propose a new similarity measure determination based on the NURBS-Warping method. In this method, the query image represented by the Non-Uniform Rational B-Spline (NURBS) descriptor is warped to best...
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ISBN:
(纸本)9810474806
In this paper, we propose a new similarity measure determination based on the NURBS-Warping method. In this method, the query image represented by the Non-Uniform Rational B-Spline (NURBS) descriptor is warped to best fit the shape of the database image. The similarity between two images is determined by measuring the effort being spent in the warping process. Four similarity parameters are derived to reflect the effort spent throughout the warping process. These parameters are the Total Cumulative Change in the Position of the Control Points (TCCPCP), Total Cumulative Change in the Curvature of the Control Points (TCCCCP), Total Cumulative Voting Distance Score (TCVDS) and degree of matching, which are used to compute the similarity measure for each database image. The retrieved database images are ranked according to the computed similarity measure. A set of experiments is carried out to investigate the characteristic of each similarity parameters that influence the similarity measure computation independently. We also validate the effectiveness of the computed similarity measure for retrieving a set of database images based on the human similarity judgement. The retrieval results of the proposed method are compared with the Curvature Scale Space (CSS) method proposed by Mokhtarian. The overall experiments results show that the similarity measure derived from the NURBS-Warping method show good retrieval results in a highly similar database.
In this paper, a new multicast routing algorithm is introduced for multi-layered satellite networks, which include GEO, MEO, and LEO layers. This sch.me aims to minimize the total cost of multicast trees in the satell...
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In this paper, a new multicast routing algorithm is introduced for multi-layered satellite networks, which include GEO, MEO, and LEO layers. This sch.me aims to minimize the total cost of multicast trees in the satellite network. Multicast trees are constructed and maintained in the dynamic satellite network topology in a distributed manner. Simulation results are provided to evaluate the performance of this sch.me in terms of end-to-end delay and multicast tree cost.
In this paper, a multicast transport protocol, called TCP-Peachtree, is proposed for satellite IP networks. In addition to the acknowledgment implosion and scalability problems appeared in terrestrial wirelined networ...
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In this paper, a multicast transport protocol, called TCP-Peachtree, is proposed for satellite IP networks. In addition to the acknowledgment implosion and scalability problems appeared in terrestrial wirelined networks, satellite multicasting has additional problems, i.e., low bandwidth feedback link, different multicast topology and congestion control problem. In TCP-Peachtree, the modified B+ tree hierarchical structure is used to form dynamic multicast groups. Local error recovery and ACK aggregations are performed within each subgroup and also via logical subgroups. Two new algorithms, Jump Start and Quick Recovery, which are based on a type of low priority segments, called NIL segments, are proposed for congestion control. NIL segments are used to probe the availability of network resources and also for error recovery. Moreover, an ACK filter is also introduced to aggregate ACKs. The simulation results show that the congestion control algorithms in TCP Peachtree outperform the TCP NewReno when combined with our hierarchical groups and ACK filter. It is also shown that TCP Peachtree can have very good scalability.
Current sensing is one of the most important functions on a smart power chip. Conventional current-sensing methods insert a resistor in the path of the current to be sensed. This method incurs significant power losses...
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Current sensing is one of the most important functions on a smart power chip. Conventional current-sensing methods insert a resistor in the path of the current to be sensed. This method incurs significant power losses, especially when the current to be sensed is high. Lossless current-sensing methods address this issue by sensing the current without dissipating the power that passive resistors do. Six available lossless current sensing techniques are reviewed. A new sch.me for increasing the accuracy of current sensing when the discrete elements are not known is introduced. The new sch.me measures the inductor value during the DC-DC controller startup.
In video-on-demand (VOD) applications, it is desirable to provide the user with the video-cassette-recorder-like (VCR) capabilities such as fast-forwarding a video or jumping to a specific frame. We address this issue...
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ISBN:
(纸本)9781581136203
In video-on-demand (VOD) applications, it is desirable to provide the user with the video-cassette-recorder-like (VCR) capabilities such as fast-forwarding a video or jumping to a specific frame. We address this issue in the broadcast framework, where each video is broadcast repeatedly on the network. Existing techniques rely on data prefetching as the mechanism to provide this functionality. This approach provides limited usability since the prefetching rate cannot keep up with typical fast-forward speeds. Fast-forwarding a video for several seconds would inevitably exhaust the prefetch buffer. We address this practical problem in this paper by repeatedly broadcasting the interactive versions of the videos. For instance, an interactive version might contain only every fifth frame in the original video. Our client software leverages these "interactive" broadcasts to provide better VCR service. We formally prove the correctness of this approach, and compare its performance to a prefetch method, called active buffer management. This sch.me has been shown to offer, in the broadcast environment, the best performance to date. Our simulation results indicate that the new technique is superior in handling long-duration VCR actions.
Video-cassette-recorder-like (VCR) capabilities such as jumping to a specific frame or fast forwarding a video are becoming essential services in video-on-demand (VOD) applications. To provide VCR functionalities in a...
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Video-cassette-recorder-like (VCR) capabilities such as jumping to a specific frame or fast forwarding a video are becoming essential services in video-on-demand (VOD) applications. To provide VCR functionalities in a broadcast environment, current techniques depend on data prefetching. However, a fast-forward or a fast-backward of a video for several seconds would certainly exhaust the prefetch buffer because the prefetching rate cannot sustain typical speeds. In this paper we address this practical problem where each video and its interactive version are broadcast repeatedly on the network. For example, interactive versions might contain only every fifth frame in the original videos. We propose a new technique that leverages these "interactive" broadcasts to provide better VCR service.
This work presents an innovative design of a high frequency and potentially highly efficient boost DC-DC converter with an input voltage of 2.7-3.3 Volts and with a programmable output voltage of 4-9 Volts. Current so...
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This work presents an innovative design of a high frequency and potentially highly efficient boost DC-DC converter with an input voltage of 2.7-3.3 Volts and with a programmable output voltage of 4-9 Volts. Current sourcing capability is between 40 mA-360 mA. A low power boost DC-DC converter designed in CMOS which partially uses circuit macro-models -designed and tested using Cadence tools- for an all CMOS silicon process illustrates this design. The key features of this design are very high switching frequency, reconfigurability, silicon all CMOS implementation, and mixed signal simulation capability. The boost converter has a simulation switching frequency of 5 MHz, an average efficiency of 50% and an output ripple voltage of about 30 mV.
In this paper, group-wise successive interference cancellation (GSIC) receiver with adaptive minimum mean squared error (MMSE) detection and extended GSIC (EGSIC) receiver with adaptive MMSE detection are proposed for...
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In this paper, group-wise successive interference cancellation (GSIC) receiver with adaptive minimum mean squared error (MMSE) detection and extended GSIC (EGSIC) receiver with adaptive MMSE detection are proposed for dual-rate DS-CDMA system. Users are divided into 2 groups for their data rates: high-rate (HR) users and low-rate (LR) users. Initial bit estimates for the HR users are obtained by adaptive MMSE detection. Multiple access interference (MAI) between the HR users is cancelled by parallel interference cancellation (PIC) and updated bit estimates for the HR users are obtained. Then, the estimates for the received signals of the HR users are regenerated using the updated bit estimates and summed up to be subtracted from the received signal. The initial bit estimates for the LR users are obtained by adaptive MMSE detection using the received signal with MAI from the HR users being subtracted. MAI between the LR users is cancelled by PIC and updated bit estimates for the LR users are obtained. It is possible to extend the proposed receiver. In the extended GSIC (EGSIC) receiver with adaptive MMSE detection, an extra stage is added which takes the interference from the LR users to the HR users into account. It is shown that the EGSIC receiver with adaptive MMSE detection achieves significant performance improvement over the MF receiver, EGSIC receiver for dualrate DS-CDMA system in a Rayleigh fading channel.
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