Optimization of tag reading performance in generation-2 RFID protocol

Radio frequency identification (RFID) provides a non-line-of-sight (NLOS) and contactless approach for object identification. But if there are multiple tags in the range of an RFID reader, tag collision can take place due to radio signal interference and therefore an anti-collision algorithm is required to resolve collisions. Recently, EPCglobal RFID generation-2 (Gen-2) protocol [EPCglobal Specification, EPCTM radio-frequency identity protocols class-1 generation-2 UHF RFID protocol for communications at 860 MHz–960 MHz, version 1.0.9, January 2005. Available from: <http://www.epcglobalinc.org>] is proposed for ultra-high frequency (UHF) passive tags and is being deployed. Gen-2 designs a slotted random anti-collision algorithm, especially, an adaptive slot-counter (Q) selection algorithm. The integer-valued parameter Q in Gen-2 plays a critical role in tag collision resolution. This adaptive algorithm dynamically adjusts the value of Q based on the type of replies from tags. In this paper, we propose an optimal Q algorithm that determines the optimal values of Q according to the number of remaining tags and in turn to optimize tag identification speed (TIS) and query success rate (QSR), respectively. It’s been demonstrated through extensive simulations that the proposed algorithm achieves higher TIS than Gen-2 adaptive Q algorithm.     

Novel compact dual‐narrow/wideband branch‐line couplers using T‐Shaped stepped‐impedance‐stub lines

This article presents a compact model to reduce the physical size and increase the frequency ratio between the second and first resonance frequencies of a dual‐function stepped‐impedance‐stub (SIS) line, which was subsequently employed in the realization of dual‐band branch‐line couplers. The proposed model comprises of a loaded spiral T‐shaped SIS that reduces the size of a conventional SIS line as well as improving its frequency ratio. The proposed model behaves exactly similar to the recently developed dual‐band resonators with the advantage of size reduction of ～35% as well as having a wide range of realizable frequency ratios between 1.4 and 3.7 compared to 1.7–2.7 and 1.8–2.3 for the conventional SIS and T‐shaped transmission‐lines, respectively. Dual‐narrowband and wideband branch‐line couplers were developed based on the spiral T‐shaped SIS lines. The dual‐wideband device's bandwidth was enhanced by 2.7% accompanied by a size reduction of 58.6% in comparison with the conventional dual‐wideband couplers operating at the same frequencies. The theoretical results were verified by measurement. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Replacing 100% of phenol in phenolic adhesive formulations with lignin

Lignin, produced as a byproduct of pulp and paper and bioethanol industries, is a polyphenolic compound that has excellent potential to be used as phenol replacement in phenolic adhesive formulation. In this study, the phenol portion of phenol formaldehyde (PF) resin has been replaced by an agricultural‐based lignin, which was produced as a byproduct of a cellulosic bioethanol process through dilute‐acid pretreatment and enzymatic hydrolysis from corn stover. The PF resol resin was formulated using isolated lignin under alkaline condition. Chemical, physical, and thermal properties of the isolated lignin, PF resin and adhesive were measured using advanced analytical techniques such as Fourier transformed infrared spectroscopy (FTIR), size exclusion chromatography (SEC), phosphorous nuclear magnetic resonance spectroscopy (³¹P NMR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The developed 100% lignin‐based adhesive and a commercially formulated phenol resorcinol formaldehyde (PRF, as reference) were used to prepare single‐lap‐joint samples for mechanical testing. The plywood samples were pressed under exactly the same conditions (time, temperature, and pressure) as what recommended for the commercial PRF formulation. According to two‐way ANOVA results, statistically there was no significant difference between the shear strengths of plywood samples made with 100% lignin‐based adhesive and those made with the commercial PRF resin. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45124.     

Voice communications over zigbee networks

This article provides an overview of ZigBee-enabled wireless networks and discusses the feasibility of supporting voice communications over ZigBee networks. We begin by providing an overview of the ZigBee technology followed by an evaluation of voice quality and performance over such an impoverished wireless channel. Two types of voice communications, namely full-duplex voice over IP (VoIP) and half-duplex push-to-talk (PTT) are considered. Voice quality of VoIP is measured using the R-factor [1] (a well known objective speech quality metric). The quality of PTT, however, is evaluated based on packet-loss rate, delay, and jitter. The simulation results demonstrate that a low-power, low-rate wireless sensor network can support a limited range of voice services.     

Energy‐efficient cluster division for multi‐cell joint transmission technology

Coordinated Multi‐Point (CoMP) is an effective way to improve user performance in next‐generation wireless cellular networks, such as 3GPP LTE‐Advanced(LTE‐A). The base station cooperation can reduce interference, and increase the signal to interference and noise ratio (SINR) of cell‐edge users and improve the system capacity. However, the base station cooperation also adds additional power consumption for signal processing and sharing information through back‐haul links between cooperative base stations. As such, CoMP may potentially consume more energy. This paper studies such energy consumption issue in CoMP, presents a semi‐dynamic CoMP cluster division algorithm based on energy efficiency (SCCD‐EE) that can effectively adapt to users' real‐time interference, and employs the idea of Maximal Independent Set (MIS) to solve the problem of cluster overlapping. To verify the feasibility of the proposed algorithm, this paper performs comprehensive evaluations in terms of energy efficiency and system capacity. The simulation results show that the proposed semi‐dynamic cluster division algorithm can not only improve the system capacity and the quality of service (QoS) of cell‐edge users, but also achieve higher network energy efficiency compared with static cluster methods and Non‐CoMP approaches. Copyright © 2016 John Wiley & Sons, Ltd.     

Development of amitriptyline buccoadhesive tablets for management of pain in dental procedures

Administration of lidocaine and nonsteroidal anti-inflammatory drugs (NSAIDs) as a routine procedure for relief of dental pains by and large is restricted due to some side effects. Amitriptyline (AM) has long been known to exert analgesic activity as a result of blocking the Na? channels. The objective of the present investigation was to prepare suitable buccoadhesive tablets using cellulose derivatives in order to obtain new formulations containing AM to provide local analgesic action. The tablets were evaluated in terms of physical characteristics, mucoadhesion performance, drug release, and in vivo assessment of analgesic efficiency. Tablets containing higher amounts of high-viscosity hydroxypropylmethyl cellulose (HPMC-K4M) significantly demonstrated enhanced adhesive performances. On the other hand, presence of sodium carboxymethyl cellulose (NaCMC) in formulations including HPMC of lower-viscosity grade (HPMC-E5LV) provided further adhesiveness by increase in viscosity. Rate of drug release from HPMC-E5LV tablets was significantly higher than the HPMC-K4M tablets. Kinetically, patterns of AM release from the tablets fitted best to Higuchi model. Moreover, in a randomized double-blind trial, analgesic efficiency of the prepared bioadhesive tablets was revealed to be satisfactory. It is suggested that applying the topical AM mucoadhesive tablet containing the low amount of drug is a safe and promising alternative to relief the pain in the buccal region.     

A Store-and-Forward Cooperative MAC for Wireless Ad Hoc Networks

Cooperative communications are widely used to increase the throughput of wireless networks. It is important to select the appropriate relay nodes to enhance the performance of cooperative communications. In wireless ad hoc networks, such as IEEE802.11 WLAN, the distributed MAC is used to share the wireless channel to different nodes. In this work, a simple store-and-forward cooperative MAC (SFC-MAC) is proposed, which is fully compatible with IEEE 802.11 MAC. In SSF-MAC, the relay node just stores the packets received from the sender and forward them to the receiver after it successfully contend the channel. Furthermore, an model is built to analyze the performance of relay methods in the ideal channel and imperfect channel. We utilize throughput performance as a metric to determine whether a relay node is selected. The analysis and simulation results show that the proposed simple SSF-MAC can increase the system throughput.     

A 3D hybrid BE–FE solution to the forward problem of electrical impedance tomography

This paper presents a three dimensional (3D) hybrid boundary element–finite element (BE–FE) method solution to the electrical impedance tomography (EIT) forward problem. EIT is a method to find the distribution of electrical conductivity within an object through injecting current on surface electrodes placed on the object, and measuring the distribution of potential around the object. Existing 3D models are based on the finite element (FE) method and the boundary element (BE) method. In this paper, a hybrid BE–FE method approach is demonstrated for modeling the forward problem of EIT. Such a hybrid BE–FE technique combines strengths of FE and BE methods by dividing the regions into some homogeneous BE regions and heterogeneous FE regions. To validate numerical results, a homogenous test problem is solved analytically for the electrical potential. A cylindrical model of human thorax is studied. Results obtained for this model from BE, FE, and hybrid BE–FE methods with three different meshes and two different electrode placement strategies are compared.     

Antenna Power Cutback Manipulation to Optimize Relay Power Allocation over MAMR Networks Employing Zero Forcing Scheme

Power allocation between relays and data streams is an important aspect of MIMO relay systems. Different methods are designed to consider weight matrices within relay channels. Commonly employed methods are based on linearly distributed multi antenna relay beamforming with match filter, zero forcing and MMSE techniques. This article proposes a cutback relay power allocation technique to design a suboptimal beamforming weight matrix by ZF–ZF method to decrease BER considerably at high SNRs. This method allocates the unused relay antenna power to others through the associated relay. This allows maximum workable power to increase; consequently the system performance is improved.