An 8-bit 100-kS/s successive approximation (SA) analog-to-digital converter (ADC) is proposed for measuring EEG and MEG signals in an 88 point. The architectures of a SA ADC with a single-ended analog input and a split-capacitor-based digital-to-analog converter (SC-DAC) are used to reduce the power consumption and chip area of the entire ADC. The proposed SA ADC uses a time-domain comparator that has an input offset self-calibration circuit. It also includes a serial output interface to support a daisy channel that reduces the number of channels for the multi-point sensor interface. It is designed by using a 0.35-µm 1-poly 6-metal CMOS process with a 3.3 V supply to implement together with a conventional analog circuit such as a low-noise-amplifier. The measured DNL and INL of the SA ADC are +0.63/-0.46 and +0.46/-0.51 LSB, respectively. The SNDR is 48.39 dB for a 1.11 kHz analog input signal at a sampling rate of 100 kS/s. The power consumption and core area are 38.71 µW and 0.059 mm2, respectively.

In our privious paper, we proposed an algorithm that determines delay times of a timed Petri net from the structural information of a signaling pathway, but Petri net structures containing cycles and inhibitory arcs were not considered. This paper provides conditions for cycle-contained Petri nets to have reasonable delay times. Furthermore, handling of inhibitory arcs are discussed in terms of the reaction rate of inhibitory interaction in signaling pathway, especially the conversion process of Petri net with inhibitory arc to the one without inhibitory arc is given.

A workflow net N may be extended as another workflow net N' by adding nodes and arcs. N' is intuitively called a subclass of N under protocol inheritance if we cannot distinguish those behaviors when removing the added transitions. Protocol inheritance problem is to decide whether N' is a subclass of N under protocol inheritance. It is known that the problem is decidable but is intractable. Even if N is a subnet of N', N' is not always a subclass of N under protocol inheritance. In this paper, limiting our analysis to protocol inheritance between acyclic extended free-choice workflow nets and their subnets, we gave a necessary and sufficient condition on the problem. Based on the condition, we also constructed a polynomial time procedure for solving the problem.

The Generalized cross-correlation (GCC) method is most commonly used for time delay estimation (TDE). However, the GCC method can result in false peak errors (FPEs) especially at a low signal to noise ratio (SNR). These FPEs significantly degrade TDE, since the estimation error, which is the difference between a true time delay and an estimated time delay, is larger than at least one sampling period. This paper introduces an algorithm that estimates two peaks for two cross-correlation functions using three types of signals such as a reference signal, a delayed signal, and a delayed signal with an additional time delay of half a sampling period. A peak selection algorithm is also proposed in order to identify which peak is closer to the true time delay using subsample TDE methods. This paper presents simulations that compare the algorithms' performance for varying amounts of noise and delay. The proposed algorithms can be seen to display better performance, in terms of the probability of the integer TDE errors, as well as the mean and standard deviation of absolute values of the time delay estimation errors.

This paper provides a sufficient condition to construct timed-release public-key encryption (TRPKE), where the constructed TRPKE scheme guarantees strong security against malicious time servers, proposed by Chow et al., and strong security against malicious receivers, defined by Cathalo et al., in the random oracle model if the component IBE scheme is IND-ID-CPA secure, the component PKE scheme is IND-ID-CPA secure, and the PKE scheme satisfies negligible γ-uniformity for every public key. Although Chow et al. proposed a strongly secure TRPKE scheme, which is concrete in the standard model, to the best of our knowledge, the proposed construction is the first generic one for TRPKE that guarantees strong security even in the random oracle model.

The broadcast scheduling problem (BSP) in wireless ad-hoc networks is a well-known NP-complete combinatorial optimization problem. The BSP aims at finding a transmission schedule whose time slots are collision free in a wireless ad-hoc network with time-division multiple access (TDMA). The transmission schedule is optimized for minimizing the frame length of the node transmissions and maximizing the utilization of the shared channel. Recently, many metaheuristics can optimally solve smaller problem instances of the BSP. However, for complex problem instances, the computation of metaheuristics can be quite time and memory consuming. In this work, we propose a greedy genetic algorithm for solving the BSP with a large number of nodes. We present three heuristic genetic operators, including a greedy crossover and two greedy mutation operators, to optimize both objectives of the BSP. These heuristic genetic operators can generate good solutions. Our experiments use both benchmark data sets and randomly generated problem instances. The experimental results show that our genetic algorithm is effective in solving the BSP problem instances of large-scale networks with 2,500 nodes.

In this paper, we study decentralized supervisory control of timed discrete event systems, where we adopt the OR rule for fusing local enablement decisions and the AND rule for fusing local enforcement decisions. Under these rules, necessary and sufficient conditions for the existence of a decentralized supervisor that achieves a given specification language are easily obtained from the result of literature. If a given specification language does not satisfy these existence conditions, we must compute its sublanguage satisfying them. The main contribution of this paper is proposing a method for computing such a sublanguage.

This paper discusses hybrid state saving for applications in which processes should create checkpoints at constant intervals and can hold a finite number of checkpoints. We propose a reclamation technique for checkpoint space, that provides effective checkpoint time arrangements for a rollback distance distribution. Numerical examples show that when we cannot use the optimal checkpoint interval due to the system requirements, the proposed technique can achieve lower expected overhead compared to the conventional technique without considering the form of the rollback distance distribution.

We propose the asynchronous receiver-initiated MAC protocol with the stair-like sleep mode; each node reduces its own sleep time by the sleep-change-rate depending on the number of hops from the source to the sink in wireless sensor networks (WSNs). Using the stair-like sleep approach, our protocol achieves high delivery ratio, low packet delay, and high energy efficiency due to the reduction in idle listening time. Our protocol can formulate the upper bound of the idle listening time because of the feature that the sleep time decreases in a geometric progression, and the reduction of the idle listening time is obtained by using the stair-like sleep approach. In our proposed scheme, the sink calculates the sleep change rate based on the number of hops from the source to the sink. By using the control packets which have the role of the acknowledgment (ACK), our proposed protocol can achieve the stair-like sleep with no additional control packets. In addition, even in the network condition that multi-targets are detected, and the number of hops to the sink are changed frequently, our proposed protocol can change the sleep change rate adaptively because the sink can always obtain the number of hops from the source to the sink. Simulation results show that the proposed protocol can improve the performance in terms of the packet delivery ratio, the packet delay, and the energy efficiency compared to the conventional receiver-initiated MAC (RI-MAC) protocol.

In this paper, we present Greedy Routing for Maximum Lifetime (GRMax) [1],[2] which can use the limited energy available to nodes in a Wireless Sensor Network (WSN) in order to delay the dropping of packets, thus extend the network lifetime. We define network lifetime as the time period until a source node starts to drop packets because it has no more paths to the destination [3]. We introduce the new concept of Network Connectivity Aiming (NCA) node. The primary goal of NCA nodes is to maintain network connectivity and avoid network partition. To evaluate GRMax, we compare its performance with Geographic and Energy Aware Routing (GEAR) [4], which is an energy efficient geographic routing protocol and Greedy Perimeter Stateless Routing (GPSR) [5], which is a milestone among geographic routing protocol. We evaluate and compare the performance of GPSR, GEAR, and GRMax using OPNET Modeler version 15. The results show that GRMax performs better than GEAR and GPSR with respect to the number of successfully delivered packets and the time period before the nodes begin to drop packets. Moreover, with GRMax, there are fewer dead nodes in the system and less energy is required to deliver packets to destination node (sink).

An accurate and rapid synchronization scheme is a prerequisite for achieving high-quality multimedia transmission for wireless handheld terminals, e.g. China multimedia mobile broadcasting (CMMB) system. In this paper, an efficient orthogonal frequency division multiplexing (OFDM) timing synchronization scheme, which is robust to the doubly selective fading channel, is proposed for CMMB system. TS timing is derived by performing an inverse sliding correlation (ISC) between the segmented Sync sequences in the Beacon, which possesses the inverse conjugate symmetry (ICS) characteristic. The ISC can provide sufficient correlative gain even in the ultra low signal noise ratio (SNR) scenarios. Moreover, a fast fine symbol timing method based on the auto-correlation property of Sync sequence is also presented. According to the detection strategy for the significant channel taps, the specific information about channel profile can be obtained. The advantages of the proposed timing scheme over the traditional ones have been demonstrated through both theoretical analysis and numerical simulations.

In this paper, a hybrid parallel implementation of inverse matrix computation using SMW formula is proposed. By aggregating the memory bandwidth in the hybrid parallel implementation, the bottleneck due to the memory bandwidth limitation in the authors previous multicore implementation has been dissolved. More than 8 times of speed up is also achieved with dual-core 8-nodes implementation which leads more than 20 simulation steps per second, or near real-time performance.

This paper presents comprehensive comparisons based on the block error rate (BLER) of open-loop (OL) transmit diversity schemes considering a cubic metric (CM) for single-carrier (SC)-Frequency Division Multiple Access (FDMA) using discrete Fourier transform (DFT)-precoded OFDMA in uplink frequency-selective fading channels. The OL transmit diversity schemes assumed in the paper are space-time block code (STBC), space-frequency block code (SFBC), single-carrier (SC) - SFBC, cyclic delay diversity (CDD), and frequency switched transmit diversity (FSTD) for two antennas and a combination of STBC, SFBC, SC-SFBC and selection transmit diversity including time switched transmit diversity (TSTD) or FSTD for four antennas. We derive the most appropriate OL transmit diversity scheme for SC-FDMA using a frequency domain equalizer (FDE) with QPSK and 16QAM modulations and with various channel coding rates employing turbo coding. We investigate the best OL transmit diversity scheme under various propagation channel conditions including the fading maximum Doppler frequency and root mean square (r.m.s.) delay spread, and the fading correlation between transmitter/receiver antennas.

In this paper, using the Linear Time Variant (LTV) phase noise model and considering higher order harmonics generated by the oscillator output signal, a more general formula for transformation of the excess phase to the output signal is presented. Despite the basic LTV model which assumes that the total carrier power is within the fundamental harmonic, in the proposed model, the total carrier power is assumed to be distributed among all output harmonics. For the first harmonic, the developed expressions reduce to the basic LTV formulas. Simulation and experimental results are used to ensure the validity of the model.

In this letter, the tradeoff between symbol rate and diversity gain of Space-Time Block Codes (STBCs) with linear receivers is considered. It is known that Group Orthogonal-Toeplitz Codes (GOTCs) can achieve a good tradeoff with linear receivers. However, the symbol rate of GOTCs is limited to that of the base Orthogonal Space-Time Block Codes (OSTBCs). We propose to simply change the GOTC base codes from OSTBCs to Quasi-Orthogonal Space-Time Block Codes (Q-OSTBCs). Q-OSTBCs can improve the symbol rate of GOTCs at the expense of diversity gain. Simulation results show that Q-OSTBC based GOTCs can improve the tradeoff between symbol rate and diversity gain over that of the original GOTCs.

A high-speed low-complexity time-multiplexing Reed-Solomon-based forward error correction architecture based on the pipelined truncated inversionless Berlekamp-Massey algorithm is presented in this paper. The proposed architecture has very high speed and very low hardware complexity compared with conventional Reed-Solomon-based forward error correction architectures. Hardware complexity is improved by employing a truncated inverse Berlekamp-Massey algorithm. A high-speed and high-throughput data rate is facilitated by employing a three-parallel processing pipelining technique and modified syndrome computation block. The time-multiplexing method for pipelined truncated inversionless Berlekamp-Massey architecture is used in the parallel Reed-Solomon decoder to reduce hardware complexity. The proposed architecture has been designed and implemented with 90-nm CMOS technology. Synthesis results show that the proposed 16-channel Reed-Solomon-based forward error correction architecture requires 417,600 gates and can operate at 640 MHz to achieve a throughput of 240 Gb/s. The proposed architecture can be readily applied to Reed-Solomon-based forward error correction devices for next-generation short-reach optical communications.

A scheme that modulates the training sequence is proposed to support two-layer data streams in the time domain synchronous orthogonal frequency division multiplex (TDS-OFDM) systems. A theoretical analysis and computer simulation show that the proposed scheme works well and that the two layer data streams are compatible with each other.

Microblogs are a rising social network with distinguishing features such as simplicity and convenience and has already attracted a large number of users and triggered massive information explosion concerning individuals' own statuses and opinions. While sentiment analysis of the messages in microblogs is of great value, most of present studies are on English microblogs and few are on Chinese microblogs. Compared to English, Chinese has its unique expression style, such as no spaces or other word delimiters. Furthermore, Chinese short text also has its own properties. Thus we are inspired to explore effective features for sentiment classification of Chinese short text. In this paper, we propose to study user-related sentiment classification of Chinese microblogs in terms of the statistical and semantic characteristics, and deisgn the corresponding features: ratio of positive words and negative words (PNR), position feature (POS), collocation of verbs (COL), auxiliary words (AU). Then we employ an SVM-based method to classify the sentiment. Experiments show that the features we design is effective in recognizing the sentiment of messages in microblogs.

To acquire a second language, one must develop an ear and tongue for the correct stress and intonation patterns of that language. In English language teaching, there is an effective method called Jazz Chants for working on the sound system. In this paper, we propose a method for predicting stressed words, which play a crucial role in Jazz Chants. The proposed method is specially designed for stress prediction in Jazz chants. It exploits several sources of information including words, POSs, sentence types, and the constraint on the number of stressed words in a chant text. Experiments show that the proposed method achieves an F-measure of 0.939 and outperforms the other methods implemented for comparison. The proposed method is expected to be useful in supporting non-native teachers of English when they teach chants to students and create chant texts with stress marks from arbitrary texts.

This paper proposes a video-quality estimation method based on a no-reference model for realtime quality monitoring in video-streaming services. The proposed method analyzes both bitstream information and decoded pixel information to estimate video-quality degradation by transmission errors. Video quality in terms of a mean squared error (MSE) between degraded video frames and error-free video frames is estimated on the basis of the number of impairment macroblocks in which the quality degradation has not been possible to be concealed. Error-concealment effectiveness is evaluated using motion information and luminance discontinuity at the boundaries of impairment regions. Simulation results show a high correlation (correlation coefficients of 0.93) between the actual MSE and the number of macroblocks in which error concealment has not been effective. These results show that the proposed method works well in reatime quality monitoring for video-streaming services.