We herein propose a MAC protocol for the smart antenna network, which applies pulse/tone exchange prior to the RTS/CTS handshake process. RTS frame collisions are drastically reduced with little additional overhead due to pulse/tone exchange in the proposed protocol. In addition, the number of exposed nodes is reduced by using smart antennas. Furthermore, since the occurrence of the deafness problem can be identified by pulse/tone exchange failure, retransmission is conducted using a fixed contention window value. Therefore, the wastage of wireless resources due to the deafness problem is reduced. As a result, the network throughput can be effectively improved compared with that for previous protocols. Simulation results demonstrate the validity and effectiveness of the proposed protocol.

Grazing incidence X-ray diffraction experiment proved that the a- and c-axes of PMDA-ODA crystals preferentially aligned in normal and parallel directions to rubbing at surface of rubbed film, and that polymer chains of residual amorphous phase aligned in rubbing direction.

Microwave photoconductivity decay (µ-PCD) method was applied to evaluate the effects of chemical composition and Ar+ plasma induced damage on the bulk and the surface states in amorphous In-Ga-Zn-O (a-IGZO) films. It was found that the peak reflectivity signal in the photoconductivity response increased with decreasing the Ga content, and had a strong correlation with the a-IGZO transistor performances. In addition, the peak reflectivity signals obtained after various Ar+ plasma treatment duration were well correlated with the transistor characteristics. With Ar+ plasma treatment, the peak reflectivity signal decreased in accordance with degradation of transistor characteristics. The µ-PCD method was found to be a very useful tool not only to evaluate the bulk and the surface states, but also to predict the performance of a-IGZO transistors subjected to various plasma processes in the production.

In this paper, a block-constrained trellis coded vector quantization (BC-TCVQ) algorithm is combined with an algebraic codebook to produce an algebraic trellis vector code (ATVC) to be used in ACELP coding. ATVC expands the set of allowed algebraic codebook pulse position, and the trellis branches are labeled with these subsets. The Viterbi algorithm is used to select the excitation codevector. A fast codebook search method using an efficient non-exhaustive search technique is also proposed to reduce the complexity of the ATVC search procedure while maintaining the quality of the reconstructed speech. The ATVC block code is used as the fixed codebook of AMR-NB (12.2 kbps), which reduces the computational complexity compared to the conventional algebraic codebook.

A one-dimensional ad hoc network with a single active source–destination pair is analyzed in terms of transport capacity, where each node uses multiple antennas. The analysis is based on using a multi-hop opportunistic routing transmission in the presence of fading. Specifically, the lower and upper bounds on the transport capacity are derived and their scaling law is analyzed as the node density, λ, is assumed to be infinitely large. The lower and upper bounds are shown to have the same scaling (ln λ)1/α, where α denotes the path-loss exponent. We also show that using multiple antennas at each node does not fundamentally change the scaling law.

In this paper, we constructed a class of low correlation zone sequence sets derived from the interleaved technique and DFT matrices. When p is a prime such that p > 3, p-ary LCZ sequence sets with parameters LCZ(pn-1,pm-1,(pn-1)/(pm-1),1) are constructed based on a DFT matrix with order pp, which is optimal with respect to the Tang-Fan-Matsufuji bound. When p is a prime such that p ≥ 2, pk-ary LCZ sequence sets with parameters LCZ(pn-1,pk-1,(pn-1)/(pk-1),1) are constructed based on a DFT matrix with order pkpk, which is also optimal. These sequence sets are useful in certain quasi-synchronous code-division mutiple access (QS-CDMA) communication systems.

In the letter, we propose an improved histogram shifting (HS) based reversible data hiding scheme for small payload embedding. Conventional HS based schemes are not suitable for low capacity embedding with relatively large distortion due to the inflexible side information selection. From an analysis of the whole HS process, we develop a rate-distortion model and provide an optimal adaptive searching approach for side information selection according to the given payload. Experiments demonstrate the superior performance of the proposed scheme in terms of performance curve for low payload embedding.

Vision based human action recognition has been an active research field in recent years. Exemplar matching is an important and popular methodology in this field, however, most previous works perform exemplar matching on the whole input video clip for recognition. Such a strategy is computationally expensive and limits its practical usage. In this paper, we present a martingale framework for selection of characteristic frames from an input video clip without requiring any prior knowledge. Action recognition is operated on these selected characteristic frames. Experiments on 10 studied actions from WEIZMANN dataset demonstrate a significant improvement in computational efficiency (54% reduction) while achieving the same recognition precision.

Recently a simple algorithm was presented by the first author which enables one to successively compute the transformation matrix of various order for the general 1-D to 1-D polynomial transformation. This letter extends the result to the general 1-D to 2-D polynomial transformation. It is also shown that the matrix obtained can be used for the 2-D to 2-D polynomial transformation as well.

In this paper, a capacitive-cross-coupling common-gate (CCC-CG) LNA using capacitive feedback is proposed to improve the noise figure (NF). In the conventional CCC-CG LNA, the transconductance gm is determined by the input-matching condition while a lager gm is required to improve NF. gm of the proposed LNA can be increased and NF can be improved by using the added capacitive feedback. The analytical calculation shows that the proposed LNA can perform better than the conventional CCC-CG LNA. In the measurement results using a 0.18-µm CMOS technology, the gain is 10.4–13.4 dB, NF is 2.7–2.9 dB at 0.8–1.8 GHz, and IIP3 is -7 dBm at 0.8 GHz. The power consumption is 6.5 mW with a 1.8-V supply.

This paper proposes a low-phase-noise ring-VCO-based frequency multiplier with a new subharmonic direct injection locking technique that only uses a time-delay cell and four MOS transistors. Since the proposed technique behaves as an exclusive OR and can double the reference signal frequency, it increases phase correction points and achieves low phase noise characteristic across the wide output frequency range. The frequency multiplier was fabricated by using 65 nm Si CMOS process. Measured 1-MHz-offset phase noise at 6.34 GHz with reference signals of 528 MHz was -119 dBc/Hz.

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.

PMIPv6 is the IETF standard for a network-based localized mobility management protocol. In PMIPv6, MNs are topologically anchored at an LMA, which forwards all data for registered MNs. However, since all data packets destined for MNs always traverse the MNs' LMA, the end-to-end packet delay is increased. Therefore, this paper proposes an RO scheme in single and multiple LMA environments. For efficient RO possibility detection, an IPv6 RO extension header and initial RO procedure are proposed. Plus, an effective post-handover RO procedure is presented, along with a packet forwarding scheme to avoid the race condition problem during an RO operation. A Performance evaluation confirms that the proposed scheme can significantly reduce the end-to-end delay, signaling overhead, and RO latency when compared with existing RO schemes.

A can swells due to gas produced from an inner food caused by poor hermetic sealing of the can. This paper presents a measurement for the bottom shape to detect a swelled can by using the millimeter-wave imaging. For get higher spatial resolution and an adjustable focal distance, two collimated beam lenses were applied to the measurement system. First, a configuration of the system was studied with the electrical field intensity and focal distance by using full wave electromagnetic simulation. Next, the bottom shapes of cans with different pressure were evaluated quantitatively using the system. A shape change of 0.5 mm was detected with pressure difference of 50 kPa, and it is reasonable considering actual dimension of the can shape. A potential of the proposed detection method was presented.

One of promising application offered by implant body area networks (BANs) is a capsule endoscope localization system. To begin with, this paper performs finite-difference time-domain (FDTD) simulations on implant BAN propagation with a numerical human model, and investigates the propagation characteristics of implant BAN signals at 400 MHz medical implant communication service (MICS) band. Then, the paper presents a capsule endoscope localization system which utilizes only received signal strength indicator (RSSI) and two estimation methods, such as a maximum likelihood (ML) estimation method and a least squares (LS) method. Furthermore, we evaluate the two localization methods by two computer simulation scenarios. Our computer simulation results demonstrate that the ML localization can improve the location estimation accuracy as compared with the LS localization, that is, our performance comparison reveals that a careful consideration the propagation characteristics of implant BANs signals is efficient in terms of estimation performance improvement in capsule endoscope localization.

Microwave interconnects have been proposed recently to break-down long wires in large integrated circuits. In this paper, using of coplanar waveguide RF interconnects in FPGAs is explored to improve performance and reduce routing congestion. We propose a new FPGA architecture consisting of both metal wires and RF receivers/transmitters corresponding with an algorithm to route the proposed FPGA. Experimental results show that used routing tracks and routing congestion are reduced by 23.8% and 7.06%, respectively and performance of the attempted benchmarks is improved by about 33% using this technique. These benefits are earned in reasonable cost of area and power consumption which is negligible for large and complex circuits.

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 presents a novel approach for mobile positioning in IEEE 802.11a wireless LANs with acceptable computational complexity. The approach improves the positioning accuracy by utilizing the time and frequency domain channel information obtained from the orthogonal frequency-division multiplexing (OFDM) signals. The simulation results show that the proposed approach outperforms the multiple signal classification (MUSIC) algorithm, Ni's algorithm and achieve a positioning accuracy of 1 m with a 97% probability in an indoor scenario.