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.

This paper proposes Burst Error Resilient coding (BRC) technology in mobile broadcasting network. The proposed method utilizes Scalable Video Coding (SVC) and Forward Error Correction (FEC) to overcome service outage due to burst loss in mobile network. The performance evaluation is performed by comparing PSNR of SVC and the proposed method under MBSFN simulation channel. The simulation result shows PSNR of SVC equal error protection (EEP), unequal error protection (UEP) and proposed BRC using Raptor FEC code.

We propose a system to provide accurate data and timely medical services, unconstrained by location, through the use of a platform that can utilize mobile devices, interface with sensors and medical information systems. As the application of integrated platform, we aim to develop medical services that manage thrombolytic therapy for emergent stroke patients.

This paper proposes non-coherent multiple-input multi-ple-output (MIMO) communication systems employing per transmit antenna differential mapping (PADM), which generates an independent differentially encoded sequence for each of the multiple transmit antennas by means of space-time coding and mapping. At a receiver, the proposed PADM employs adaptive maximum-likelihood detection (MLD). The features of PADM are as follows: 1) it has excellent tracking performance for fast time-varying fading channels, because it can detect transmitted data without needing channel state information (CSI); 2) it can be applied not only to transmit diversity (TD) but also to spatial multiplexing (SM). In this paper, we analyze the adaptive MLD based on pseudo matrix inversion and derive its metric for data detection. In order to satisfy requirements on multiple transmitted sequences for the adaptive MLD, this paper proposes a mapping rule for PADM. Next, this paper describes a receiver structure based on per-survivor processing (PSP), which can drastically reduce the complexity of adaptive MLD. Finally, computer simulations confirm that the proposed non-coherent MIMO communication systems employing PADM have excellent tracking capability for TD and SM on fast time-varying fading channels.

In this letter we design a new family of space-time block codes (STBC) for multi-input multi-output (MIMO) systems. The complex orthogonal STBC achieves full diversity and full transmission rate with fast maximum-likelihood decoding when only two transmit antennas are employed. By combining the Alamouti STBC and the multidimensional signal constellation rotation based on the cyclotomic number field, we construct cyclotomic orthogonal space-time block codes (COSTBCs) which can achieve full diversity and full rate for multiple transmit antennas. Theoretical analysis and simulation results demonstrate excellent performance of the proposed codes, while the decoding complexity is further reduced.

In this letter, we propose a channel-aware scheduling algorithm to support real-time applications in wireless multimedia sensor networks. Multimedia streams are sensitive to real-time delivery but can tolerate some packet loss. Therefore, this specific application is modelled as an (m,k)-firm stream. To satisfy the real-time requirements, a scheduling scheme that provides packet partitioning and real-time delivery is proposed. Packet partitioning combines static assignment and dynamic adjustment while considering the channel state. The scheme is designed to minimize the number of mandatory packets delivered in a bad channel state to avoid dynamic failure. In addition, automatic repeat request technology is introduced to enhance the reliability of real-time delivery. Simulations and analyses show that the proposed scheme has a good ability to withstand a bad channel status.

This paper presents a response time acceleration technique in a high-gain capacitive-feedback frontend amplifier (FA) for high output impedance sensors. Using an auxiliary amplifier as a unity-gain buffer, a sample-and-hold capacitor which is used for band-limiting and sampling the FA output is driven at the beginning of the transient response to make the response faster and then it is re-charged directly by the FA output. A condition and parameters for the response time acceleration using this technique while maintaining the noise level unaffected are discussed. Theoretical analysis and simulation results show that the response time can be less than half of the case without the acceleration technique for the specified settling error of less than 0.5%.

In the infrastructure-less disaster environment, the application of the peer-to-peer (P2P) group conference over mobile ad hoc network (MANET) can be used to communicate with each other when the rescue crews search the survivors but work separately. However, there still are several problems of in-time multimedia delivery in P2P-MANET: (1) MANET mobility influences the maintenance of P2P overlay. (2) P2P overlay is not proximal to MANET topology, this leads to the inefficient streaming delivery. (3) The unreliable wireless connection leads to the difficulty of multi-source P2P group conferencing. Therefore, P2P conferencing cannot work well on MANET. To overcome the above disadvantages, in this paper, we present a cross-layer P2P group conferencing mechanism over MANET, called RING (Real-time Intercommunication Network Gossip). The RING uses the ring overlay to manage peers and utilizes the cross-layer mechanism to force the ring overlay to be proximal to MANET topology. Therefore, RING can lead efficient in-time multimedia streaming delivery. On the other hand, the ring overlay can deal with peer joining/leaving fast and simply, and improves the delivery efficiency with the minimum signaling overhead. Through mathematical theory and a series of experiments, we demonstrate that RING is workable and it can shorten the source-to-end delay with minimal signaling overhead.

The IEEE has recently released IEEE 802.15.5 standard [3] to provide multi-hop mesh functions for low-rate wireless personal area networks (WPANs). In this paper, we extensively describe a link-layer reliable broadcast protocol referred to as timer-based reliable broadcast (TRB) [3] in the IEEE 802.15.5 standard. The TRB scheme exploits (1) bitmap based implicit ACK to effectively reduce the unnecessary error control messages and (2) randomized timer for ACK transmission to substantially reduce the possibility of contentions. Performance evaluation shows that the TRB scheme achieves 100% reliability compared with other schemes with expense of slightly increased energy consumption.

Discrete-Time fractional Brownian motion (DFBM) and its increment process, called discrete-time fractional Gaussian noise (DFGN), are usually used to describe natural and biomedical phenomena. These two processes are dominated by one parameter, called the Hurst exponent, which needs to be estimated in order to capture the characteristics of physical signals. In the previous work, a variance estimator for estimating the Hurst exponent directly via DFBM was provided, and it didn't consider point selection for linear regression. Since physical signals often appear to be DFGN-type, not DFBM-type, it is imperative to first transform DFGN into DFBM in real applications. In this paper, we show that the variance estimator possesses another form, which can be estimated directly via the autocorrelation functions of DFGN. The above extra procedure of transforming DFGN into DFBM can thus be avoided. On the other hand, the point selection for linear regression is also considered. Experimental results show that 4-point linear regression is almost optimal in most cases. Therefore, our proposed variance estimator is more efficient and accurate than the original one mentioned above. Besides, it is also superior to AR and MA methods in speed and accuracy.

Arc discharge generated by breaking electrical contact is considered as a main source of not only degradation of the electrical property but also an undesired electromagnetic (EM) noise. In order to clarify the effect of heated temperature on the bridge, arc-duration and the fluctuation of voltage, opening-waveforms at slowly separating silver-tin dioxide contact with holder heating are measured and discussed experimentally in this paper. Firstly, opening-waveforms are measured. Secondly, voltage fluctuation of the each arc-phase is discussed to extract the effect of the heated holder. The relationship between temperature of the heated holder and duration and fluctuation of the arc was investigated experimentally. It was revealed that as the initial temperature of the heated holder becomes higher, arc-duration becomes slightly longer. In addition, voltage fluctuation at the gaseous-phase decreases when the holder is heated. Consequently, the heated holder can suppress the voltage fluctuation even if its duration becomes slightly longer.

This study proposes an improved per-survivor-processing (PSP) scheme to tackle the phase error issue in the convolutionally coded OFDM systems. The proposed approach takes advantage of the trellis structure of the convolutional codes to compensate the symbol-time-offset (STO) caused phase error in frequency domain. Unlike the traditional PSP scheme which simply estimates the phase error by using a state-based horizontal process, the proposed approach develops an extra state-wise vertical process which selects the most likely phase estimate as the survival phase in each trellis stage and then accordingly align the phase of all states to this survival phase before moving to next trellis stage of the PSP scheme. With the vertical process, the resultant phase estimate is more reliable than that of the conventional PSP scheme and hence improve the accuracy in data decoding. Computer simulations confirm the validity of the proposed approach.

Wireless multimedia sensor networks tend to generate a large number of sensing data packets within a short period. A multi-channel TDMA scheme can avoid the hidden terminal problem and and has been shown to achieve higher performance than the CSMA scheme. In order to deliver large volumes of sensing data within a time limit, our scheme for minigroup multicast can improve the performance gain of the multi-channel TDMA by incorporating deflection routing which constrains any intermediate nodes from serving multiple sessions and establishes a new path detour the nodes on the existing path of multicast sessions. Through simulations, we show that, even though the deflection routing builds non-optimal paths, our scheme supports 95% packet delivery ratio and higher throughput than the legacy multicast routing protocol with CSMA-based media access control.

The authors have been investigating degradation process of Au plated slip ring and Ag-Pd-Cu brush system. In almost all cases the lifetime of the sliding system ends, when Au plating layer is worn out, the ring surface is oxidized to be black in color and contact resistance becomes very high. Further, the lifetime is very short without lubricant. So, the lubricant is very effective to make the lifetime longer. However, even with lubricant the lifetime is varied from about 1000 hours to almost 7000 hours in the past experiments. It is an important issue how the lubricant works on the lifetime of the system. In this paper the effect of lubricant on the degradation process of contact resistance is focused on. In the past tests the lubricant is supplied only once before the test. In this test the lubricant is regularly supplied almost every 900 operation hours. Consequently, the operation more than 8000 hours is realized, which is the longest among tests so far. In addition the contact voltage drop increase gradually until 2600 hours and after that it stays almost constant around 70 mV. According to the Element Analysis after the test the Ni base plating layer is totally exposed in many tracks. It means that the Au plating layer is gradually worn out probably at the stage of increasing voltage drop. In the previous tests the lifetime ended even when the Ni plating layer remained. So, the reason of long operation in this test is guessed to be that the lubricant not only decreases wear of ring and brush, but also suppresses oxidation of the Ni layer.

In this paper, we propose a novel in-network aggregation scheduling scheme for forest fire monitoring in a wireless sensor network. This adaptively configures both the timeout and the collecting period according to the potential level of a fire occurrence. At normal times, the proposed scheme decreases a timeout that is a wait time for packets sent from child nodes and makes the collecting period longer. That reduces the dissipated energy of the sensor node. Conversely, the proposed scheme increases the timeout and makes the collecting period shorter during fire occurrences in order to achieve more accurate data aggregation and early fire detection.

There are various existing methods translating timed Petri nets to timed automata. However, there is a trade-off between the amount of description and the size of state space. The amount of description and the size of state space affect the feasibility of modeling and analysis like model checking. In this paper, we propose a new translation method from timed Petri nets to timed automata. Our method translates from a timed Petri net to an automaton with the following features: (i) The number of location is 1; (ii) Each edge represents the firing of transition; (iii) Each state implemented as clocks and variables represents a state of the timed Petri net one-to-one correspondingly. Through these features, the amount of description is linear order and the size of state space is the same order as that of the Petri net. We applied our method to three Petri net models of signaling pathways and compared our method with existing methods from the view points of the amount of description and the size of state space. And the comparison results show that our method keeps a good balance between the amount of description and the size of state space. These results also show that our method is effective when checking properties of timed Petri nets.

We propose a methodology of loop design optimization for fourth-order fractional-N phase locked loop (PLL) frequency synthesizers featuring a short settling time of 5 µsec for applications in an active RFID (radio frequency identification) and automobile smart-key systems. To establish the optimized design flow, equations presenting the relationship between the specification and PLL loop parameters in terms of settling time, loop bandwidth, phase margin, and phase noise are summarized. The proposed design flow overcomes the settling time inaccuracy in conventional second-order approximation methods by obtaining the accurate relationship between settling time and loop bandwidth with the MATLAB Control System Toolbox for the fourth-order PLLs. The proposed flow also features the worst-case design by taking account of the process, voltage, and temperature (PVT) variations in loop filter components, and considers the tradeoff between phase noise and area. The three-step optimization process consists of 1) the derivation of the accurate relationship between the settling time and loop bandwidth for various PVT conditions, 2) the derivation of phase noise and area as functions of area-dominant filter capacitance, and 3) the derivation of all PLL loop components values. The optimized design result is compared with circuit simulations using an actually designed fourth-order fractional-N PLL in a 1.8 V 0.18 µm CMOS technology. The error between the design and simulation for the setting time is reduced from 0.63 µsec in the second-order approximation to 0.23 µsec in the fourth-order optimization that proves the validity of the proposed method for the high-speed settling operations.

This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

This letter investigates an iterative learning control with advanced output data (ADILC) scheme for non-minimum phase (NMP) systems when the number of NMP zeros is unknown. ADILC has a simple learning structure that can be applied to both minimum phase and NMP systems. However, in the latter case, it is assumed that the number of NMP zeros is already known. In this paper, we propose an ADILC scheme in which the number of NMP zeros is unknown. Based on input-to-output mapping, the learning starts from the relative degree. When the input becomes larger than a certain upper bound, we redesign the input update law which consists of the relative degree and the estimated value for the number of NMP zeros.