An efficient pad assignment methodology to minimize voltage drop on a power distribution network is proposed. A combination of successive pad assignment (SPA) with incremental matrix inversion (IMI) determines both location and number of power supply pads to satisfy drop voltage constraint. The SPA creates an equivalent resistance matrix which preserves both pad candidates and power consumption points as external ports so that topological modification due to connection or disconnection between voltage sources and candidate pads is consistently represented. By reusing sub-matrices of the equivalent matrix, the SPA greedily searches the next pad location that minimizes the worst drop voltage. Each time a candidate pad is added, the IMI reduces computational complexity significantly. Experimental results including a 400 pad problem show that the proposed procedures efficiently enumerate pad order in a practical time.

A method for fast but yet accurate performance evaluation of processor architecture is mostly desirable in modern processors design. This paper proposes one such method which can measure cycle counts and power consumption of pipelined processors. The method first develops a trace-driven performance simulation model and then employs simulation reuse in simulation of the model. The trace-driven performance modeling is for accuracy in which performance simulation uses the same execution traces as constructed in simulation for functional verification. Fast performance simulation can be achieved in a way that performance for each instruction in the traces is evaluated without evaluation of the instruction itself. Simulation reuse supports simulation speedup by elimination of an evaluation at the current state, which is identical to that at a previous state. The reuse approach is based on the property that application programs, especially multimedia applications, have many iterative loops in general. A performance simulator for pipeline architecture based on the proposed method has been developed through which greater speedup has been made compared with other approaches in performance evaluation.

Timing optimization is an important goal of global routing in deep submicron era. To guarantee the timing performance of the circuit, merely adopting topology optimization becomes inadequate. In this paper, we present an efficient timing-driven global routing algorithm with buffer insertion. Our approach is capable of applying topological-based timing optimization and buffer insertion simultaneously with routablity considerations. Compared with previous works, we efficiently solve the timing issues under a limited buffer usage. The experimental results have demonstrated significant delay improvement within short runtime with very small number of buffers inserted.

The objectives of the End-to-End Reconfigurability (E2R) research project are to bring the full benefits of the valuable diversity within the radio eco-space, composed of a wide range of systems (such as cellular, wireless local area and broadcast), and to devise, develop and trial architectural design of reconfigurable devices and supporting system functions to offer an expanded set of operational choices to the different actors of the value chain in the context of heterogeneous mobile radio systems. The E2R project will help operators to better exploit their investments on infrastructures and terminals and ensure that the infrastructure will be flexible and reconfigurable to accommodate evolving standards, applications and the end-user needs. E2R is seen by many actors of the wireless industry as a core technology to enable the full potential of beyond 3G systems. It has the potential to revolutionize wireless just as the PC revolutionized computing. This paper presents the E2R research project, its architectural framework and approach, the main fields of investigations across the different technical workpackages in 2005, as well as the E2R Phase 2 project proposal ambitions (2006-2007).

A recursive quadratic programming (RQP) approach is proposed for multiuser detection in multicarrier code-division multiple-access (MC-CDMA) systems. In this approach, the combinatorial problem associated with the optimal maximum likelihood (ML) detection is relaxed to a quadratic programming (QP) problem first and then a recursive approach is developed to improve the detection performance. Computer simulations are presented which demonstrate that the detector developed based on the proposed approach offers close-to-optimal symbol-error rate (SER) performance which outperforms several existing suboptimal detectors.

In this paper, we present a new all-digital carrier recovery loop for high-order quadrature amplitude modulation (QAM) signal constellations. The proposed approach is a blind phase-frequency detector structure that consists of a phase detector, a phase offset estimator, a frequency offset estimator, and a digital control oscillator. Compared to previous related approaches, the proposed algorithm provides a wider acquisition range and a more accurate estimation of frequency and phase offsets. These features are demonstrated by simulation results of the DOCSIS (Data-Over-Cable Service Interface Specifications) cable modem system.

Recently, a number of techniques have been introduced to exploit multiuser diversity of a wireless multiple-input multiple-output (MIMO) broadcast channel (BC) that consists of a base station with t transmit antennas and K users with multiple antennas. However, prior works have ignored the rate overhead associated with feedback of MIMO BC channel state information at transmitter (CSIT), which is roughly K times larger than single-user MIMO CSIT (i.e., it is O(tr) where r = rk and rk is the number of antennas at the kth user). Considering the amount of feedback signaling, quantization is a necessity for effective feedback transmission as a form of partial CSIT. In this paper, we propose the greedy multi-channel selection diversity (greedy MCSD) scheme based on block MMSE QR decomposition with dirty paper coding (block MMSE-DP), where partial CSIT is almost sufficient. The sum-rate performance of our novel scheme approaches extremely close to the sum capacity of MIMO BC as the number of users increases, whereas the feedback overhead is reduced by a factor of 2t3/L(t2-t), in which L is the number of active channel vectors. Simulation results validate the expectation from the analysis. In addition, the proposed scheme is shown to be appropriate for reconfigurable implementation.

Driving methods for TFT-OLEDs are explained with their features and classified from the viewpoints of grayscale methods and uniformizing methods. This classification leads us to a novel proposal using time ratio grayscale and current uniformization. This driving method maintains current uniformity and simultaneously overcomes charging shortage of the pixel circuit for low grayscale levels and current variation due to the shift of operating points. Tolerance toward degraded characteristics, linearity of grayscale and luminance uniformity against degraded characteristics are confirmed using circuit simulation.

The requirement for achieving the smoothness of mode transit between track seeking and track following has become a challenging issue for hard disk drive (HDD) motion control. In this paper, a random-optimization-based self-organizing neuro-fuzzy controller (RO-SNFC) for HDD servo system is presented. The proposed controller is composed of three designs. First, the concept of pseudo-errors is used to detect the potential dynamics of the unknown plant for rule extraction. Second, the propensity of the obtained pseudo-errors is specified by a cubic regression model, with which the cluster-based self-organization is implemented to generate clusters. The generated clusters are regarded as the antecedents of the T-S fuzzy "IF-THEN" rules. The initial knowledge base of the RO-SNFC is established. Third, the well-known random optimization (RO) algorithm is used to evolve the controller parameters for control efficiency and robustness. In this paper, a motion reference curve for HDD read/write head is employed. With the reference velocity curve, the RO-SNFC is used to achieve the optimal positioning control. From the illustrations, the feasibility of the proposed approach for HDD servo systems is demonstrated. Through the comparison to other approaches, the excellent performance by the proposed approach in access time and positioning smoothness is observed.

A novel evolutionary algorithm is described for designing the topology of spanning tree-based communication networks. Two specific performance objectives are dealt with: the optimum communication spanning tree problem (OCSTP), and the quadratic minimum spanning tree problem (q-MST). Improved network performance is reliably obtained when using the proposed algorithm on accepted benchmark instances, in comparison with the previous best-known approaches. The same methodology can be applied straightforwardly to the design of communication networks with other objectives.

The voltage margin of an embedded DRAM's sense operation has been shrinking with the scaling of process technology. A method to estimate this margin would be a key to optimizing the memory array configuration and the size of the sense transistor. In this paper, the voltage margin of the sense operation is theoretically analyzed. The accuracy of the proposed voltage margin model was confirmed on a 0.13-µm eDRAM test chip, and the results of calculation were generally in agreement with the measured results.

There is increasing evidence from in vivo recordings in monkeys trained to respond to stimuli by making left- or rightward eye movements, that firing rates in certain groups of neurons in oculo-motor areas mimic drift-diffusion processes, rising to a (fixed) threshold prior to movement initiation. This supplements earlier observations of psychologists, that human reaction-time and error-rate data can be fitted by random walk and diffusion models, and has renewed interest in optimal decision-making ideas from information theory and statistical decision theory as a clue to neural mechanisms. We review results from decision theory and stochastic ordinary differential equations, and show how they may be extended and applied to derive explicit parameter dependencies in optimal performance that may be tested on human and animal subjects. We then briefly describe a biophysically-based model of a pool of neurons in locus coeruleus, a brainstem nucleus implicated in widespread norepinephrine release. This neurotransmitter can effect transient gain changes in cortical circuits of the type that the abstract drift-diffusion analysis requires. We also describe how optimal gain schedules can be computed in the presence of time-varying noisy signals. We argue that a rational account of how neural spikes give rise to simple behaviors is beginning to emerge.

In reconstructing 3-D from images based on feature points, one usually defines a triangular mesh that has these feature points as vertices and displays the scene as a polyhedron. If the scene itself is a polyhedron, however, some of the displayed edges may be inconsistent with the true shape. This paper presents a new technique for automatically eliminating such inconsistencies by using a special template. We also present a technique for removing spurious occluding edges. All the procedures do not require any thresholds to be adjusted. Using real images, we demonstrate that our method has high capability to correct inconsistencies.

This paper focuses on developing a square root (SQRT) algorithm in finite fields GF(p2d) (d 0). Examining the Smart algorithm, a well-known SQRT algorithm, we can see that there is some computation overlap between the Smart algorithm and the quadratic residue (QR) test, which must be implemented before a SQRT computation. It makes the Smart algorithm inefficient. In this paper, we propose a new QR test and a new SQRT algorithm in GF(p2d), in which not only there is no computation overlap, but also most of computations required for the proposed SQRT algorithm in GF(p2d) can be implemented in the corresponding subfields GF(p2d-i) for 1 i d, which yields many reductions in the computational time and complexity. The computer simulation also shows that the proposed SQRT algorithm is much faster than the Smart algorithm.

Limit cycle oscillations of rotor speed are substantially caused by inverter's dead time, when an induction motor (IM) drive operates in low frequency condition. In this paper, without any hardware modification, discontinuous PWM (DPWM3) modulate strategy possibly controls the unfavorable rotor speed limit cycle under no load operation condition. Simulated results are presented to demonstrate the effectiveness.

A timing-driven placement algorithm based on path topology analysis is presented. The optimization for path delay is transformed into cell location optimization. The algorithm pays much attention on path topologies and applies an effective force directed method to find cell target locations. Total wire length optimization is combined with the timing-driven placement algorithm. MCNC (Microelectronics Centre of North-Carolina) standard cell benchmarks are experimented and results show that our timing-driven placement algorithm can make the longest path delay improve up to 13% compared with wirelength driven placement.

Although the Digital Rights Management (DRM) systems have been rapidly developed to protect copyrights, they have not considered user privacy because they regard this as an unnecessary element in achieving their goals. However, the protection of user privacy becomes one of the most important issues in DRM systems as the number of people who suffer from accidents caused by the infringement of individual information dramatically increases. This paper suggests a license management protocol which is a more powerful protocol to protect individual information in DRM. To protect the exposure of information of user identification, the proposed protocol uses alias like a TID and a token instead of the identity of content users. Due to using alias, this protocol can guarantee the anonymity of content users. Also, it can prevent the leakage of individual information through encryption of usage information. In this way, it can protect the privacy of content users.

Polarimetric calibration of radar is indispensable for using radar data effectively. This paper proposes a polarimetric radar calibration algorithm using polarization-preserving and polarization-selective reflectors as reference targets. The algorithm assumes radar antenna reciprocity but allows different co-polarization transmission characteristics between horizontal and vertical polarization channels. In processing, the second order terms of small cross-talk factors in antenna polarization transfer characteristics are ignored. The major advantage of the present algorithm is that it does not need assumptions on the scattering characteristics of the background natural surface and is independent of external phase calibration. The results of error analysis show that the present algorithm has sufficient tolerance against errors of reference targets. The validity of the present algorithm was evaluated by analyzing the Spaceborne Imaging Radar C (SIR-C) data and the results were satisfactory.

A fully integrated clock and data recovery circuit with the proposed gated frequency detector (GFD) is presented. It has been realized in a standard 0.25-µm CMOS technology. The proposed voltage-controlled oscillator (VCO) can achieve wide operation range and reasonable conversion gain by employing the analog/digital dual loop architecture. The characteristics of small VCO gain can help to reduce loop bandwidth without enlarge the capacitors and relax the constraint on choosing the loop parameter to reduce the size of the on-chip capacitor. The proposed GFD will make the frequency lock time fixed and can avoid the harmonic locking problem in digital domain for wide data rate operations. All measured BERs are less than 10-12 with the data rate from 1.7 Gbps to 3.125 Gbps.

In this paper, dosimetry of an in vitro exposure apparatus based on a cylindrical waveguide is performed. The SAR distributions are first obtained numerically by using FDTD method. The thermal fields in the medium are then estimated by numerical calculations of the equation of heat conduction. The maximum temperature rise for 17.9 W/kg average SAR during 3000 s exposure is about 2 on the bottom of the medium where cells are located. The thermal distribution is relatively uniform near the center of the dish and the temperature in this region is around 38.7. The results of the numerical calculation are experimentally supported. The results provide the electromagnetic and thermal characteristics of the exposure apparatus, which will define the exposure conditions of the planned experiments using this apparatus.