This paper presents the formal analysis of the feature negotiation and connection management procedures of the Datagram Congestion Control Protocol (DCCP). Using state space analysis we discover an error in the DCCP specification, that result in both ends of the connection having different agreed feature values. The error occurs when the client ignores an unexpected Response packet in the OPEN state that carries a valid Confirm option. This provides an evidence that the connection management procedure and feature negotiation procedures interact. We also propose solutions to rectify the problem.

Artificial lighting is responsible for a large portion of total energy consumption and has great potential for energy saving. This paper designs an LED light control algorithm based on users' localization using multiple battery-less binary human detection sensors. The proposed lighting control system focuses on reducing office lighting energy consumption and satisfying users' illumination requirement. Most current lighting control systems use infrared human detection sensors, but the poor detection probability, especially for a static user, makes it difficult to realize comfortable and effective lighting control. To improve the detection probability of each sensor, we proposed to locate sensors as close to each user as possible by using a battery-less wireless sensor network, in which all sensors can be placed freely in the space with high energy stability. We also proposed to use a multi-sensor-based user localization algorithm to capture user's position more accurately and realize fine lighting control which works even with static users. The system is actually implemented in an indoor office environment in a pilot project. A verification experiment is conducted by measuring the practical illumination and power consumption. The performance agrees with design expectations. It shows that the proposed LED lighting control system reduces the energy consumption significantly, 57% compared to the batch control scheme, and satisfies user's illumination requirement with 100% probability.

This contribution presents and analyzes the statistical regularity related to the noise power spectrum series and the speech spectrum series. It also undertakes a thorough inquiry of the quasi-Gaussian distributed power spectrum series obtained using the radical root transformation. Consequently, a noise-estimation algorithm is proposed for speech enhancement. This method is effective for separating the noise power spectrum from the noisy speech power spectrum. In contrast to standard noise-estimation algorithms, the proposed method requires no speech activity detector. It was confirmed to be conceptually simple and well suited to real-time implementations. Practical experiment tests indicated that our method is preferred over previous methods.

This letter introduces a new model for backscatter assisted wireless powered communication networks (BAWPCNs) that include a hybrid access point (HAP) and multiple backscatter communication (BackCom) and traditional wireless powered communication network (WPCN) users. To make full use of time to transmit information, both backscatter and harvest-then-transmit (HTT) modes are employed. In the proposed model, during the first time slot dedicated for energy transfer in traditional WPCNs, the traditional WPCN users harvest energy radiated by the HAP, and simultaneously the BackCom users reflect modulated signals to the HAP. The traditional WPCN users are scheduled during the remaining time slots via time division multiple access (TMDA). The optimal time allocation policies for the half-duplex (HD) and full-duplex (FD) BAWPCNs are obtained to maximize the system throughput. The tradeoff between backscatter and HTT modes is analyzed. Simulation results demonstrate the superiority of the proposed model.

In the field of action recognition, Spatio-Temporal Interest Points (STIPs)-based features have shown high efficiency and robustness. However, most of state-of-the-art work to describe STIPs, they typically focus on 2-dimensions (2D) images, which ignore information in 3D spatio-temporal space. Besides, the compact representation of descriptors should be considered due to the costs of storage and computational time. In this paper, a novel local descriptor named 3D Gradient LBP is proposed, which extends the traditional descriptor Local Binary Patterns (LBP) into 3D spatio-temporal space. The proposed descriptor takes advantage of the neighbourhood information of cuboids in three dimensions, which accounts for its excellent descriptive power for the distribution of grey-level space. Experiments on three challenging datasets (KTH, Weizmann and UT Interaction) validate the effectiveness of our approach in the recognition of human actions.

This letter considers the robust transceiver design for multiple-input multiple-output interference channels under channel state information mismatch. According to alternating schemes, an adaptive algorithm is proposed to solve the minimum SINR maximization problem. Simulation results show the convergence and the effectiveness of the proposed algorithm.

This paper presents a novel framework called error case frames for correcting preposition errors. They are case frames specially designed for describing and correcting preposition errors. Their most distinct advantage is that they can correct errors with feedback messages explaining why the preposition is erroneous. This paper proposes a method for automatically generating them by comparing learner and native corpora. Experiments show (i) automatically generated error case frames achieve a performance comparable to previous methods; (ii) error case frames are intuitively interpretable and manually modifiable to improve them; (iii) feedback messages provided by error case frames are effective in language learning assistance. Considering these advantages and the fact that it has been difficult to provide feedback messages using automatically generated rules, error case frames will likely be one of the major approaches for preposition error correction.

This paper studies the supervisory control of partially observed quantitative discrete event systems (DESs) under the fixed-initial-credit energy objective. A quantitative DES is modeled by a weighted automaton whose event set is partitioned into a controllable event set and an uncontrollable event set. Partial observation is modeled by a mapping from each event and state of the DES to the corresponding masked event and masked state that are observed by a supervisor. The supervisor controls the DES by disabling or enabling any controllable event for the current state of the DES, based on the observed sequences of masked states and masked events. We model the control process as a two-player game played between the supervisor and the DES. The DES aims to execute the events so that its energy level drops below zero, while the supervisor aims to maintain the energy level above zero. We show that the proposed problem is reducible to finding a winning strategy in a turn-based reachability game.

In this paper, MWAN (Mobile Wireless Ad hoc Networks with internet connection) is considered, which is a solution for many tasks owing to its ease of use, and practicality. Recently, MWAN is required to support large data like multimedia data transfer and it is transferred through several relay nodes. There are 2 problems that cause difficulties for large data transfer through a mobile network. First one is rerouting delay by handoff and second one is network congestion caused by handoff. Also, faulty data transfer caused by handoff delay makes extra load and causes some problems for MWAN. To solve these problems and get network reliability, we propose a new multipath routing scheme that can provide solution for seamless connection while handoff. In the proposed scheme, our MWAN can support multiple paths for data transfer, maintain end-to-end connection while handoff and get new route quickly. The performance of the proposed scheme is evaluated and compared with other multipath routing scheme to show the improvement.

Let $R$ = $mathbb{F}_{p}+umathbb{F}_{p}+vmathbb{F}_{p}+uvmathbb{F}_{p}$, where u2=u, v2 and uv=vu. A relation between the support weight distribution of a linear code $mathscr{C}$ of type p4k over R and its dual code $mathscr{C}^{ot}$ is established.

CMOS amperometric sensors with a microelectrode array offer great potential for counting bacteria because of their low cost, compact size, and ease of use. This paper presents a current-integration-based CMOS amperometric sensor for high-sensitivity bacteria counting. It has a current integrator for noise reduction and reportedly the most large-scale microelectrode array (1024 × 1024). This proposed sensor can count the number of bacteria ranging from a single cell to approximately a million cells. A prototype chip was fabricated using two-poly three-metal (2P3M) 0.6-µm standard CMOS technology. A 7.6 × 7.1-mm2 chip operates from a 5V supply at 1.9mA. In addition, by using the prototype chip, we performed electrochemical measurement and partial 2D imaging of silicone through constant potential amperometry. The measurement results indicate that the proposed sensor chip was able to accurately readout redox current from the 1024 × 1024 sensor array.

This study mainly involved examining a high-directivity radiation system with spherical dielectric resonator as pseudo multipole source. The method of spherical wave expansion is focused on wherein the plane wave that is infinitely spread can be radiated from or absorbed by multipoles at the origin. It is not possible to explain this phenomenon by Huygens' principle, which is a basic principle of aperture antenna theory. Thus, in the study, a high-directivity beam design is proposed by synthesizing spherical waves. The directivity of the synthesized spherical wave corresponds with the angular momentum and angle, which is an uncertainty relation different from that of the aperture source. The estimation of the effective aperture of the synthesized spherical wave indicates that the wave intrinsic source is assumed to exist at the surface of the cutoff region. Finally, the results reveal that a radiation system without a singular point can be composed using a spherical dielectric resonator. The study discusses the potential of a high-directivity radiation system constructed by a multi-mode degenerate spherical dielectric resonator as a pseudo multipole source.

In this paper, we present sub-1-V CMOS-based electrophoresis method for small-form-factor biomolecule manipulation that is contained in a microchip. This is the first time this type of device has been presented in the literature. By combining CMOS technology with electroless gold plating, the electrode pitch can be reduced and the required input voltage can be decreased to less than 1 V. We fabricated the CMOS electrophoresis chip in a cost-competitive 0.6 µm standard CMOS process. A sample/hold circuit in each cell is used to generate a constant output from an analog input. After forming gold electrodes using an electroless gold plating technique, we were able to manipulate red food coloring with a 0-0.7 V input voltage range. The results shows that the proposed CMOS chip is effective for electrophoresis-based manipulation.

Appearance-based generic object recognition is a challenging problem because all possible appearances of objects cannot be registered, especially as new objects are produced every day. Function of objects, however, has a comparatively small number of prototypes. Therefore, function-based classification of new objects could be a valuable tool for generic object recognition. Object functions are closely related to hand-object interactions during handling of a functional object; i.e., how the hand approaches the object, which parts of the object and contact the hand, and the shape of the hand during interaction. Hand-object interactions are helpful for modeling object functions. However, it is difficult to assign discrete labels to interactions because an object shape and grasping hand-postures intrinsically have continuous variations. To describe these interactions, we propose the interaction descriptor space which is acquired from unlabeled appearances of human hand-object interactions. By using interaction descriptors, we can numerically describe the relation between an object's appearance and its possible interaction with the hand. The model infers the quantitative state of the interaction from the object image alone. It also identifies the parts of objects designed for hand interactions such as grips and handles. We demonstrate that the proposed method can unsupervisedly generate interaction descriptors that make clusters corresponding to interaction types. And also we demonstrate that the model can infer possible hand-object interactions.

Existing noise inference algorithms neglected the smooth characteristics of noise data, which results in executing slowly of noise inference. In order to address this problem, we present a noise inference algorithm based on fast context-aware tensor decomposition (F-CATD). F-CATD improves the noise inference algorithm based on context-aware tensor decomposition algorithm. It combines the smoothness constraint with context-aware tensor decomposition to speed up the process of decomposition. Experiments with New York City 311 noise data show that the proposed method accelerates the noise inference. Compared with the existing method, F-CATD reduces 4-5 times in terms of time consumption while keeping the effectiveness of the results.

In this paper, we investigate a novel preamble channel estimation (CE) method based on the compressed sensing (CS) theory in the orthogonal frequency division multiplexing system with offset quadrature amplitude modulation (OQAM/OFDM) over a frequency selective fading channel. Most of the preamble based CE methods waste power by deploying the pilots in all the subcarriers. Inspired by the CS theory, we focus on using many fewer pilots than one of traditional CE methods and realize accurate reconstruction of the channel response. After describing and analyzing the concept of OQAM/OFDM and its traditional CE methods, we propose a novel channel estimation method based on CS that requires fewer pilots in the preamble, and we design the corresponding preamble pattern to meet the requirements of CS. Simulation results validate the efficiency and superior performance of the proposed method in wireless channel.

A flexible orthogonal frequency-division multiplexing optical network enables the bandwidth to be flexibly changed by changing the number of sub-carriers. We assume that users request to dynamically change the number of sub-carriers. Dynamic bandwidth changes allow the network resources to be used more efficiently but each change takes a significant amount of time to complete. Service centric resource allocation must be considered in terms of the waiting time needed to change the number of sub-carriers. If the user demands drastically increase such as just after a disaster, the waiting time due to a chain-change of bandwidth becomes excessive because disaster priority telephone services are time-critical. This paper proposes a Grouped-elastic spectrum allocation scheme to satisfy the tolerable waiting time of the service in an optical fiber link. Spectra are grouped to restrict a waiting time in the proposed scheme. In addition, the proposed scheme determines a bandwidth margin between neighbor spectra to spectra to prevent frequent reallocation by estimating real traffic behavior in each group. Numerical results show that the bandwidth requirements can be minimized while satisfying the waiting time constraints. Additionally measurement granularity and channel alignment are discussed.

This paper addresses power saving for STAs (Wireless Stations) in WLANs (Wireless LANs). Mobile devices are increasingly used in situations in which they access WLANs. However, mobile devices consume large amounts of power when they communicate through a WLAN, and this shortens their battery lifetime. IEEE 802.11 specifies PSM (Power-Saving Mode) as the power-saving method for standard WLANs. However, the sleep conditions specified by PSM for STAs are not optimal in terms of power saving, except when the number of STAs is small, and this increases packet transfer delay. In this paper, we propose a power-saving method in which STAs reduce power consumption by sleeping for a period specified by the NAV (Network Allocation Vector) duration, which is set by an RTS/CTS handshake, and the duration of the NAV is extended by bidirectional burst transmission. To suppress the transfer delay caused by the bidirectional burst transmission, an AP (Access Point) manages the transmission deadline of each downlink packet on the basis of its acceptable value of delay and adapts the number of packets transferred in the bidirectional burst transmission. Although another existing method also uses the NAV duration to manage STA sleeping, the bidirectional burst transmission can only be initiated by the STAs themselves and the NAV is of an extremely limited duration. On the other hand, the proposed method specifies generalized bidirectional burst transmission without the limitations of the transmission initiator and the burst length within acceptable packet transfer delay. Moreover, we investigate the combination of the proposed method with PSM in order to improve the performance in situations in which the number of STAs is small by taking advantage of the combined properties of PSM and the proposed method. The evaluation results demonstrate that these proposed methods can reduce the power consumption of wireless stations and suppress packet transfer delay.

60GHz wireless communication requires analog baseband circuits having a bandwidth of about 1GHz. This paper presents a wide bandwidth current-mode low pass filter technique which involves current amplifiers, resistors and capacitors. The proposed current-mode filter is obtained by replacing an integrator employing an op-amp with another integrator employing a current amplifier. With the low input impedance current amplifier having little variation of the input impedance, the proposed filter is expected to improve linearity and power efficiency. The proposed current amplifier which employs super source follower topology with complementary input is suitable for the filter because of its class AB operation. Although simulation results shows the conventional current amplifier which employs super source follower topology without the complementary input has 12Ω variation and 30Ω input impedance, the proposed current amplifier has 1Ω variation and 21Ω input impedance. A fourth order 1GHz bandwidth filter which involves the proposed current amplifiers is designed in a 65nm CMOS technology. The filter can achieve IIP3 of 1.3dBV and noise of 0.6mVrms with power consumption of 13mW under supply voltage of 1.2V according to simulation results with layout parasitic extraction models. Active area of the filter is 380μm×170μm.

In this paper, a new effective C/N0 theoretical model for global navigation satellite system (GNSS) receiver is proposed, in the presence of continuous wave interference (CWI). The proposed model is derived based on an interesting finding, correlator may output direct current (DC) in the presence of CWI. The DC introduced by CWI eventually leads to increase of carrier power estimation. It is totally different from current assumption that interference just causes noise power increase after correlation. The proposed model is verified by simulation.