Software maintenance is a time consuming and expensive phase of a software product's life-cycle. The paper investigates the use of software design metrics to statistically estimate the maintainability of large sof...
详细信息
ISBN:
(纸本)0769508812
Software maintenance is a time consuming and expensive phase of a software product's life-cycle. The paper investigates the use of software design metrics to statistically estimate the maintainability of large software systems, and to identify error prone modules. A methodology for assessing, evaluating and, selecting software metrics for predicting software maintainability is presented. In addition, a linear prediction model based on a minimal set of design level software metrics is proposed. The model is evaluated by applying it to industrial software systems.
Grasslands are the largest of the Earth's four major vegetation types and are among the most agriculturally productive lands. Grassland management practices alter biophysical factors, such as plant species composi...
详细信息
The performance of future cellular and personal communications is expected to be limited by the "down-link" from the base station to the mobile. In this context, using sophisticated processing at the base st...
详细信息
ISBN:
(纸本)0780365143
The performance of future cellular and personal communications is expected to be limited by the "down-link" from the base station to the mobile. In this context, using sophisticated processing at the base station transmitter represents a promising method for enhancing the downlink capacity. Specifically, we consider space-time transmit processing, which exploits antenna arrays at the base station. Two extreme strategies for achieving this are space-time codes, which provide transmit diversity for combating Rayleigh fading without requiring knowledge of the space-time channel to the receiver, and transmit beamforming, which uses feedback regarding the space-time channel to increase the effective channel gain to the user of interest. We review some results regarding both space-time codes and transmit beamforming, including information-theoretic insights that show that transmit beamforming offers significant performance gains even with imperfect channel feedback. We then present the main result of the paper, which is a novel method for generating space-time channel feedback.
We propose an adaptive regularization algorithm for smoothing dense range images using a novel, first order stabilizing function. The stabilizer we suggest is based upon minimizing the reconstructed surface area and i...
详细信息
We propose an adaptive regularization algorithm for smoothing dense range images using a novel, first order stabilizing function. The stabilizer we suggest is based upon minimizing the reconstructed surface area and is derived in the native, spherical coordinate system of the range scanner. This allows adjustments to be made along only the direction of measurement, thereby preventing the data overlapping problem that can arise in dense images. Adaptation is achieved by adjusting the regularization parameter according to the results of 2D edge analysis. Results indicate effective noise suppression along with well preserved edges and details in the reconstructed, 3D surfaces.
It is known that in the absence of distortion, the minimum average sampling density for a multiband signal is given by its spectral occupancy. Furthermore, there exist nonuniform sampling patterns of the same average ...
详细信息
It is known that in the absence of distortion, the minimum average sampling density for a multiband signal is given by its spectral occupancy. Furthermore, there exist nonuniform sampling patterns of the same average sampling density such that reconstruction is feasible even if the actual spectral support of the multiband signal is unknown. This is called spectrum-blind nonuniform sampling. However, if the samples are distorted, an increased sampling density may lead to superior reconstruction.
A new CMOS differential latched comparator suitable for low voltage, low-power application is presented. The circuit consists of constant-gm rail-to-rail common-mode operational transconductance amplifier followed by ...
详细信息
A new CMOS differential latched comparator suitable for low voltage, low-power application is presented. The circuit consists of constant-gm rail-to-rail common-mode operational transconductance amplifier followed by a regenerative latch in a track and latch configuration to achieve a relatively constant delay. The use of a track and latch minimizes the total number of gain stages required for a given resolution. Potential offset from the constant-g/sub m/ differential input stage, estimated as the main source of offset, can be minimized by proper choice of transistors sizes. Simulation results show that the circuit requires less than 86 /spl mu/A with a supply voltage of 1.65 V in a standard CMOS 0.18 /spl mu/m digital process. The average delay is less than 1 ns and is approximately independent of the common-mode input voltage.
Low Earth orbit satellite networks can augment terrestrial wireless networks to provide global broadband services to users regardless of the users' locations. Delivering QoS guarantees to the users of LEO satellit...
详细信息
Low Earth orbit satellite networks can augment terrestrial wireless networks to provide global broadband services to users regardless of the users' locations. Delivering QoS guarantees to the users of LEO satellite networks is complicated since the footprints of the LEO satellites move as the satellites traverse their orbits, and thus, causing frequent user handovers between the satellites. Traffic on inter-satellite links of a particular satellite change as the user traffic served by the satellite changes with the satellite's mobility. The change in user traffic on the inter-satellite links may cause violation of QoS requirements of on-going calls. We propose a novel routing algorithm called the predictive routing protocol (PRP), that exploits the predictive nature of the LEO satellite topology to maximize the total number of users served by the system, while maintaining each user's QoS requirements. The PRP predicts the user traffic load on the inter-satellite links up to a short time in the future by using the deterministic knowledge of the LEO satellite topology, and user location information. The PRP determines multiple paths for a particular connection that effectively help avoid possible future bottlenecks as predicted by estimated future traffic on the inter-satellite links. The algorithm is compared with other non-predictive routing protocols such as IP routing by extensive simulations and it is shown that PRP can deliver deterministic QoS guarantees (such as delay jitter), without over-reserving channel bandwidth. An admission control curve has also been obtained which may be used to ensure that the desired QoS metrics may be guaranteed.
Proposes an algorithm based on simulated annealing for automatic seed matching and reconstruction using either 3 radiographic films or 3 fluoroscopic images. An algorithm for automated seed identification on fluorosco...
详细信息
ISBN:
(纸本)0780364651
Proposes an algorithm based on simulated annealing for automatic seed matching and reconstruction using either 3 radiographic films or 3 fluoroscopic images. An algorithm for automated seed identification on fluoroscopic images is also proposed. The authors present results obtained for 112 clinical cases, 100 simulated cases and one phantom reconstruction with known seed locations. Results for clinical eases are compared with results obtained using the 3-film technique.
The focus of this paper is the measuring, modeling, and decoupling of saturation-induced saliencies in carrier signal injection based sensorless control. First techniques for the measurement of saturation-induced sali...
详细信息
The focus of this paper is the measuring, modeling, and decoupling of saturation-induced saliencies in carrier signal injection based sensorless control. First techniques for the measurement of saturation-induced saliencies are presented. The goal of these measurements is to provide useful information on the position and magnitude of the various saturation-induced saliencies. Using the results from several different experimental measurements, models are developed explaining the source and behavior of the saturation-induced saliencies. The paper concludes by presenting methods for decoupling the effects caused by the parasitic saturation-induced saliencies, eliminating the errors that they cause in rotor position or flux angle estimation.
We discuss the nonlinear control of a novel biped robot with three-degrees-of-freedom and two control inputs, whose dynamics are linear apart from the gravitational torque and the impact equations. We show that the eq...
详细信息
ISBN:
(纸本)0780366387
We discuss the nonlinear control of a novel biped robot with three-degrees-of-freedom and two control inputs, whose dynamics are linear apart from the gravitational torque and the impact equations. We show that the equations of motion are locally feedback linearizable by nonlinear change of coordinates and nonlinear feedback in a region that includes all walking gaits of interest. We combine the feedback linearization control with control of the resulting linear system and the nonlinear impact equations to generate a stable walking gait.
暂无评论