In an embedded system where a single application or a class of applications is repeatedly executed on a processor, its cache configuration can be customized such that an optimal one is achieved. We can have an optimal cache configuration which minimizes overall memory access time by varying the three cache parameters: the number of sets, a line size, and an associativity. In this paper, we first propose two cache simulation algorithms: CRCB1 and CRCB2, based on Cache Inclusion Property. They realize exact cache simulation but decrease the number of cache hit/miss judgments dramatically. We further propose three more cache design space exploration algorithms: CRMF1, CRMF2, and CRMF3, based on our experimental observations. They can find an almost optimal cache configuration from the viewpoint of access time. By using our approach, the number of cache hit/miss judgments required for optimizing cache configurations is reduced to 1/10-1/50 compared to conventional approaches. As a result, our proposed approach totally runs an average of 3.2 times faster and a maximum of 5.3 times faster compared to the fastest approach proposed so far. Our proposed cache simulation approach achieves the world fastest cache design space exploration when optimizing total memory access time.

Two-dimensional (2D) matrix symbols have higher storage capacity than conventional bar-codes, and hence have been used in various applications, including parts management in factories and Internet site addressing in camera-equipped mobile phones. These symbols generally utilize strong error control codes to protect data from errors caused by blots and scratches, and therefore require a large number of check bits. Because 2D matrix symbols are expressed in black and white dot patterns, blots and scratches often induce clusters of unidirectional errors (i.e., errors that affect black but not white dots, or vice versa). This paper proposes a new class of unidirectional lm ln-clustered error correcting codes capable of correcting unidirectional errors confined to a rectangle with lm rows and ln columns. The proposed code employs 2D interleaved parity-checks, as well as vertical and horizontal arithmetic residue checks. Clustered error pattern is derived using the 2D interleaved parity-checks, while vertical and horizontal positions of the error are calculated using the vertical and horizontal arithmetic residue checks. This paper also derives an upper bound on the number of codewords based on Hamming bound. Evaluation shows that the proposed code provides high code rate close to the bound. For example, for correcting a cluster of unidirectional 40 40 errors in 150 150 codeword, the code rate of the proposed code is 0.9272, while the upper bound is 0.9284.

This paper proposes a method to construct a basis conversion matrix between two given bases in Fpm. In the proposed method, Gauss period normal basis (GNB) works as a bridge between the two bases. The proposed method exploits this property and construct a basis conversion matrix mostly faster than EDF-based algorithm on average in polynomial time. Finally, simulation results are reported in which the proposed method compute a basis conversion matrix within 30 msec on average with Celeron (2.00 GHz) when mlog p≈160.

We have introduced a new ultrasonic-based localization method that requires only one ultrasonic receiver to locate transmitters. In our previous reports [1],[2], we conducted several fundamental experiments, and proved the feasibility and accuracy of our system. However the performance in a more realistic environment has not yet been evaluated. In this paper, we have extended our localization system into a robot tracking system, and conducted experiments where the system tracked a moving robot. Localization was executed both by our proposed method and by the conventional TOA method. The experiment was repeated with different density of receivers. Thus we were able to compare the accuracy and the scalability between our proposed method and the conventional method. As a result 90-percentile of the position error was from 6.2 cm to 14.6 cm for the proposed method, from 4.0 cm to 6.1 cm for the conventional method. However our proposed method succeeded in calculating the position of the transmitter in 95% out of total attempts of localization with sparse receivers (4 receivers in about 5 m 5 m area), whereas the success rate was only 31% for the conventional method. From the result we concluded that although the proposed method is less accurate it can cover a wider area with sparse receivers than the conventional method. In addition to the dynamic tracking experiments, we also conducted some localization experiments where the robot stood still. This was because we wanted to investigate the reason why the localization accuracy degraded in the dynamic tracking. According to the result, the degradation of accuracy might be due to the systematic error in localization which is dependent on the geometric relationship between the transmitter and the receiver.

Recent progress in scaled CMOS technologies can enhance signal bandwidth and clock frequency of analog-digital mixed VLSIs. However, the inevitable reduction of supply voltage causes a signal voltage mismatch between a non-scaled analog chip and a scaled A-D mixed chip. To overcome this problem, we present a Delta-Amplifier (DeltAMP) which can handle larger signal amplitude than the supply voltage. DeltaAMP folds a delta signal of an input voltage within a window using a virtual ground amplifier, modulation switches and comparators. For reconstruction of the folded delta signal to the ordinal signal, Analog-Time-Digital conversion (ATD) was also proposed, in which pulse-width analog information obtained at the comparators in DeltAMP was converted to a digital signal by counting. A test chip of DeltAMP with ATD was designed and fabricated using a 90 nm CMOS technology. A 2 Vpp input voltage range and 50 µW power consumption were achieved by the measurements with a 0.5 V supply. High accuracy of 62 dB SNR was obtained at signal bandwidth of 120 kHz.

Multiple access based on energy spreading transform (EST) in [1] has been shown to effectively separate multiuser signals in an iterative manner. In this paper, an optimum hard-decision detector for the EST-based multiple access is proposed. The proposed scheme employs minimum mean square error (MMSE) processing at each iteration to enhance the performance of the original scheme. Analysis and simulation results show the significant performance improvement of the proposed scheme over the original method.

This paper proposes a frequency domain nulling filter and Turbo equalizer to suppress interference in the uplink of one-cell reuse single-carrier time division multiple access (TDMA) systems. In the proposed system, the desired signal in a reference cell is interfered by interference signals including adjacent-channel interference (ACI), co-channel interference (CCI), and intersymbol interference (ISI). At the transmitter, after a certain amount of spectrum is nulled considering the expected CCI, the suppressed power due to nulling is reallocated to the remaining spectrum components so as to keep the total transmit power constant. In this process, when mitigation of ACI is necessary, after a certain amount of spectrum at both edges is nulled using an edge-removal filter, the aforementioned process is conducted. At the receiver, frequency domain SC/MMSE Turbo equalizer (FDTE) is employed to suppress ISI due to spectrum nulling process in the transmitter as well as the multipath fading. Computer simulations confirm that the proposed scheme is effective in suppression of CCI, ACI and ISI in one-cell reuse single-carrier TDMA systems.

We propose a sketch-based modeling system where all user input is performed from a unique viewpoint. The strokes drawn by the user must not then be restricted to the drawing plane: their orientation in the 3D space is automatically determined by the system. The desired surface is reconstructed from a grid made of two groups of similar lines, that are considered co-planar. The orientation of the two sets of planes is determined by assuming that at the intersection of a representative line of each group, those two lines are perpendicular.

We introduce the interval timing correlation, which can establish timing correlation conditions to handle interval timing timestamps. Interval timestamps are adopted to handle the temporal uncertainties in the timestamps of stream data. A probabilistic querying approach is taken in order to support timing predicates such as deadline, delay, and within over interval timestamps. A timing correlation condition entails a desired confidence threshold (minimum satisfaction probability). We define the interval timing correlation and discuss how to implement the algorithm. We present an analysis result which can effectively identify only tuples that need to be considered in determining the correlation. The performance of the proposed algorithm is shown.

A transmission line created by cables adjoined by connectors is influenced by noise from connectors with contact failure, and such noise degrades communication quality. The authors used a model of a connector with increased contact resistance in a coaxial cable and measured the electromagnetic near-field around a cable while changing positions of the model. In this paper, the result shows that the radiated electromagnetic field has no relationship with the position along the cable of a connector with increased contact resistance, when the contact condition of connector, contact resistance value, measurement position, and length of a transmission line are constant.

Negative bias temperature instability (NBTI) has become a critical reliability phenomena in advanced CMOS technology. In this paper, we propose an analytical temperature-aware dynamic NBTI model, which can be used in two circuit operation cases: executing tasks with different temperatures, and switching between active and standby mode. A PMOS Vth degradation model and a digital circuits' temporal performance degradation estimation method are developed based on our NBTI model. The simulation results show that: 1) the execution of a low temperature task can decrease ΔVth due to NBTI by 24.5%; 2) switching to standby mode can decrease ΔVth by 52.3%; 3) for ISCAS85 benchmark circuits, the delay degradation can decrease significantly if the circuit execute low temperature task or switch to standby mode; 4) we have also observed the execution time's ratio of different tasks and the ratio of active to standby time both have a considerable impact on NBTI effect.

This paper presents a multi functional range finder employing dual imager core on a single chip. Each imager core has functionalities of 2-D imaging and 3-D capture using the light section method with combinations of the dual imager core. The presented chip achieves, 2-D imaging mode, 3-D capture mode with the conventional light-section method, high-speed 3-D capture mode with the stereo matching mode, and 2-D and 3-D simultaneous capture mode. We demonstrate 58 fps 2-D imaging with 8 bit gray scale, and 24.8 rangemaps/s 3-D range-finder with the maximum range error of 1.619 mm and the standard deviation of 0.385 mm at 700 mm.

This paper describes recent technology trend of mixed analog digital RF circuits. With the progress of CMOS technology, large-scale digital signal process and control function can be integrated in an RF integrated circuit and some analog signal process blocks can be translated to digital signal processing units. At the same time, the design of remaining analog functional blocks becomes very hard. In this paper, those integration techniques for receiver and transmitter in these 20 years are reviewed. As a typical example of digital assisted systems, synthesizer based transmitters are discussed in detail.

This Letter proposes an optimal gain filter for the perceptual acoustic echo suppressor. We designed an optimally-modified log-spectral amplitude estimation algorithm for the gain filter in order to achieve robust suppression of echo and noise. A new parameter including information about interferences (echo and noise) of single-talk duration is statistically analyzed, and then the speech absence probability and the a posteriori SNR are judiciously estimated to determine the optimal solution. The experiments show that the proposed gain filter attains a significantly improved reduction of echo and noise with less speech distortion.

We propose an automatic generative method for stylus style CG as automatic generative method for non-photorealistic CG.

This letter focuses on the simplified capacity evaluation for the downlink of a distributed antenna system (DAS) with random antenna layout. Based on system scale-up, we derive a good approximation of the downlink capacity by developing the results from random matrix theory. We also propose an iterative method to calculate the unknown parameters in the approximated expression of the downlink capacity. The approximation is illustrated to be quite accurate and the iterative method is shown to be quite efficient by Monte Carlo simulations.

Printed circuit boards (PCBs) driven by a connected feed cable are considered to be one of the main sources of the electromagnetic interference (EMI) from electronic devices. In this paper, a method for predicting the electromagnetic (EM) radiation from a PCB driven by a connected feed cable at up to gigahertz frequencies is proposed and demonstrated. The predictive model is based on the transmission line theory and current- and voltage-driven CM generation mechanisms with consideration of antenna impedance. Frequency responses of differential-mode (DM) and common-mode (CM) currents and far-electric field were investigated experimentally and with finite-difference time-domain (FDTD) modeling. First, the dominant component in total EM radiation from the PCB was identified by using the Source-Path-Antenna model. Although CM can dominate the total radiation at lower frequencies, DM is the dominant component above 3 GHz. Second, the method for predicting CM component at lower frequencies is proposed. And its validity was discussed by comparing FDTD calculated and measured results. Specifically, the relationship between the CM current and the terminating resistor was focused as important consequence for the prediction. Good agreement between the measured and predicted results shows the validity of the predicted results. The proposed model can predict CM current with sufficient accuracy, and also identify the primary coupling-mechanism of CM generation. Then far-electric field was predicted by using the proposed method, and it was demonstrated that outline of the frequency response of the undesired EM radiation from the PCB driven by the connected feed cable can be predicted with engineering accuracy (within 6 dB) up to 18 GHz. Finally, as example of application of equivalent circuit model to EMC design, effect of the width of the ground plane was predicted and discussed. The equivalent circuit model provides enough flexibility for different geometrical parameters and increases our ability to provide insights and design guidelines.

In this paper, we solve the call admission control (CAC) and routing problem in an integrated network that handles several classes of calls of different values and with different resource requirements. The problem of maximizing the average reward (or cost) of admitted calls per unit time is naturally formulated as a semi-Markov Decision Process (SMDP) problem, but is too complex to allow for an exact solution. Thus in this paper, a policy gradient algorithm, together with a decomposition approach, is proposed to find the dynamic (state-dependent) optimal CAC and routing policy among a parameterized policy space. To implement that gradient algorithm, we approximate the gradient of the average reward. Then, we present a simulation-based algorithm to estimate the approximate gradient of the average reward (called GSMDP algorithm), using only a single sample path of the underlying Markov chain for the SMDP of CAC and routing problem. The algorithm enhances performance in terms of convergence speed, rejection probability, robustness to the changing arrival statistics and an overall received average revenue. The experimental simulations will compare our method's performance with other existing methods and show the robustness of our method.

Intrusion detection system (IDS) has played an important role as a device to defend our networks from cyber attacks. However, since it is unable to detect unknown attacks, i.e., 0-day attacks, the ultimate challenge in intrusion detection field is how we can exactly identify such an attack by an automated manner. Over the past few years, several studies on solving these problems have been made on anomaly detection using unsupervised learning techniques such as clustering, one-class support vector machine (SVM), etc. Although they enable one to construct intrusion detection models at low cost and effort, and have capability to detect unforeseen attacks, they still have mainly two problems in intrusion detection: a low detection rate and a high false positive rate. In this paper, we propose a new anomaly detection method based on clustering and multiple one-class SVM in order to improve the detection rate while maintaining a low false positive rate. We evaluated our method using KDD Cup 1999 data set. Evaluation results show that our approach outperforms the existing algorithms reported in the literature; especially in detection of unknown attacks.

In order to reduce the amount of interference to neighboring cells in cellular systems, we generally use base station (BS) antennas that have sharp beam patterns in the vertical plane; however, the distribution of incoming waves at the BS affects the effective gain of the BS antennas which have directional pattern. Therefore, we have to clarify the characteristics of the distribution of the incoming waves. A recent trend is decreasing the cell radius; therefore, clarifying the distribution of the incoming waves at the BS when mobile stations (MSs) are located within 1 km from the BS is important. In this report, we evaluate the effective gains of the BS antennas, which are calculated using the measured vertical power angle profile (PAP). Moreover, we examine the application of a simple incoming wave model to the evaluation of the antenna effective gains. In the model, the average power of the incoming waves is set to the Laplacian function and each wave is changed to a lognormal distribution. The antenna effective gain calculated using the model agrees well with that calculated using the measured PAP.