Hybrid recommendations for mobile commerce based on mobile phone features

Mobile data communications have evolved as the number of third generation (3G) subscribers has increased. The evolution has triggered an increase in the use of mobile devices, such as mobile phones, to conduct mobile commerce and mobile shopping on the mobile web. There are fewer products to browse on the mobile web; hence, one‐to‐one marketing with product recommendations is important. Typical collaborative filtering (CF) recommendation systems make recommendations to potential customers based on the purchase behaviour of customers with similar preferences. However, this method may suffer from the so‐called sparsity problem, which means there may not be sufficient similar users because the user‐item rating matrix is sparse. In mobile shopping environments, the features of users' mobile phones provide different functionalities for using mobile services; thus, the features may be used to identify users with similar purchase behaviour. In this paper, we propose a mobile phone feature (MPF)‐based hybrid method to resolve the sparsity issue of the typical CF method in mobile environments. We use the features of mobile phones to identify users' characteristics and then cluster users into groups with similar interests. The hybrid method combines the MPF‐based method and a preference‐based method that uses association rule mining to extract recommendation rules from user groups and make recommendations. Our experiment results show that the proposed hybrid method performs better than other recommendation methods.     

Java based replicated server objects and their remote method invocations in a distributed environment

A distributed system is said to be fault‐tolerant if it is able to provide important services despite partial failures of the computers or software objects in the system. These systems are needed to support applications such as remote access and control, virtual mobile offices and wide area collaborative systems where there are chances of failures in the network and software objects. Fault‐tolerance is usually achieved by replicating the objects in the system. Traditional distributed applications constructed using Java RMI (remote method invocation) are not fault‐tolerant because of the lack of support of object replication. The objective of the present work is to design a remote method invocation that supports server object replication. To provide a fault‐tolerant service to the remote client objects, server objects are actively replicated. The problems associated with the method invocation in the context of active server object replication are presented and solutions are discussed and implemented. Copyright © 2001 John Wiley & Sons, Ltd.     

Procedural Synthesis using Vortex Particle Method for Fluid Simulation

We propose a fast and effective technique to improve sub‐grid visual details of the grid based fluid simulation. Our method procedurally synthesizes the flow fields coming from the incompressible Navier‐Stokes solver and the vorticity fields generated by vortex particle method for sub‐grid turbulence. We are able to efficiently animate smoke which is highly turbulent and swirling with small scale details. Since this technique does not solve the linear system in high‐resolution grids, it can perform fluid simulation more rapidly. We can easily estimate the influence of turbulent and swirling effect to the fluid flow.     

Multitask bilateral learning for real‐time image enhancement

Nowadays, deep neural networks (DNNs) for image processing are becoming more complex; thus, reducing computational cost is increasingly important. This study highlights the construction of a DNN for real‐time image processing, training various image processing operators efficiently through multitask learning. For real‐time image processing, the proposed algorithm takes a joint upsampling approach through bilateral guided upsampling. For multitask learning, the overall network is based on an encoder‐decoder architecture, which consists of encoding, processing, and decoding components, in which the encoding and decoding components are shared by all the image processing operators. In the processing component, a semantic guidance map, which contains processing information for each image processing operator, is estimated using simple linear shifts of the shared deep features. Through these components, the proposed algorithm requires an increase of only 5% in the number of parameters to add another image processing operator and achieves faster and higher performance than that of deep‐learning‐based joint upsampling methods in local image processing as well as global image processing.     

Broadband MIMO Antenna System for 5G Operations in Mobile Phones

A broadband 8‐antenna multiple‐input and multiple‐output (MIMO) system working for 5G new radio N77 (3.3‐4.2 GHz) in mobile terminals is proposed. In particular, each antenna element/unit consists of a monopole‐type meandered branch and an inverted U‐shaped self‐isolated antenna branch; and the antenna unit is fed by the meandered branch. The antenna unit has two resonances generated separately by each branch of the antenna unit. Since the monopole couples strongly with the self‐isolated antenna element that has the inherent self‐isolation characteristics, quite good isolation for the broadband 8‐antenna MIMO system can be obtained. The results such as antenna efficiency, radiation patterns, envelope correlation coefficient, and channel capacity are also presented.     

Microcantilever sensors with embedded piezoresistive transistor read-out: Design and characterization

Microcantilevers are very effective tools in detecting of small amount of bio-species and chemicals. Recent advances in metal-oxide-semiconductor field effect transistor (MOSFET) as a transducer to detect the molecule binding-induced cantilever deflection has gained extensive attention due to its high sensitivity and direct compatibility with micro-electro-mechanical system (MEMS) sensors. In this paper, six different piezoresistive nMOSFET-embedded microcantilevers are designed and characterized to systematically study the impacts of different cantilever and transistor channel geometries on the device sensitivity. It is found that the amount of change in the drain current is the same range as reported in the literature. For point-loading applications, transistors with lower channel width are optimal for relative drain current change even though their absolute current output is less. In particular, the embedded nMOSFET Exhibits 63.6% higher sensitivity by decreasing transistor channel width from 300 to 60 μm. Furthermore, theoretical results are compared with experimental data to optimize cantilever and transistor geometrical factors to achieve higher stress or force sensitivity. The low frequency noise characteristics of the devices show better resolution for higher aspect-ratio transistors, with drain current noise in the nanoampere range. Results reveal useful design guidelines to enhance the MOSFET-embedded microcantilever sensitivity for various applications.     

3D imaging application in the studies of micro air vehicles

3D techniques are increasingly used in aerospace industry to improve quality and performance of aircrafts. This paper presents a 3D imaging technique for studying the aerodynamic shape and flight performance of micro air vehicles. 3D stereoscopic vision, based upon stroboscopic imaging, was utilized to obtain the 3D information of the aircraft's flexible aerodynamic surface. The aircraft models with deformable aerodynamic shape were designed and tested in a purpose-built wind tunnel experimental environment. After calculation of SIFT feature points and subdivision of triangular meshes, deformable surface of the aircraft's aerodynamic shape was represented. The aircraft's 3D visualization was used for analyzing unsteady deformation in the aerodynamic shape under external airflow disturbances. The results, together with aerodynamic forces measured in the experiment, will be useful to improve the flight performance and disturbance resistance ability of micro air vehicles.     

Self‐Assembled Pd@CeO2/γ‐Al2O3 Catalysts with Enhanced Activity for Catalytic Methane Combustion

Pd@CeO₂/Al₂O₃ catalysts are of great importance for real applications, such as three‐way catalysis, CO oxidation, and methane combustion. In this article, the Pd@CeO₂ core@shell nanospheres are prepared via the autoredox reaction in aqueous phase. Three kinds of methods are then employed, that is, electrostatic interaction, supramolecular self‐assembly, and physical mixing, to support the as‐prepared Pd@CeO₂ nanospheres on γ‐Al₂O₃. A model reaction of catalytic methane‐combustion is employed here to evaluate the three Pd@CeO₂/γ‐Al₂O₃ samples. As a result, the sample Pd@CeO₂‐S‐850 prepared via supramolecular self‐assembly and calcined at 850 °C exhibits superior catalytic performance to the others, which has a far lower light‐off temperature (T₅₀ of about 364 °C). Moreover, almost no deterioration of Pd@CeO₂‐S‐850 is observed after five sequent catalytic cycles. The analysis of H₂‐TPR curves concludes that there exists hydrogen spillover related to the strong metal–support interaction between Pd species and oxides. The strong metal–support interaction and the specific surface areas might be responsible for the catalytic performance of the Pd@CeO₂ samples toward catalytic methane combustion.     

Fast and Highly Sensitive Ionic‐Polymer‐Gated WS2–Graphene Photodetectors

The combination of graphene with semiconductor materials in heterostructure photodetectors enables amplified detection of femtowatt light signals using micrometer‐scale electronic devices. Presently, long‐lived charge traps limit the speed of such detectors, and impractical strategies, e.g., the use of large gate‐voltage pulses, have been employed to achieve bandwidths suitable for applications such as video‐frame‐rate imaging. Here, atomically thin graphene–WS₂ heterostructure photodetectors encapsulated in an ionic polymer are reported, which are uniquely able to operate at bandwidths up to 1.5 kHz whilst maintaining internal gain as large as 10⁶. Highly mobile ions and the nanometer‐scale Debye length of the ionic polymer are used to screen charge traps and tune the Fermi level of the graphene over an unprecedented range at the interface with WS₂. Responsivity R = 10⁶ A W^?1 and detectivity D* = 3.8 × 10¹¹ Jones are observed, approaching that of single‐photon counters. The combination of both high responsivity and fast response times makes these photodetectors suitable for video‐frame‐rate imaging applications.     

Dielectrophoresis‐Assisted Integration of 1024 Carbon Nanotube Sensors into a CMOS Microsystem

Carbon‐nanotube (CNT)‐based sensors offer the potential to detect single‐molecule events and picomolar analyte concentrations. An important step toward applications of such nanosensors is their integration in large arrays. The availability of large arrays would enable multiplexed and parallel sensing, and the simultaneously obtained sensor signals would facilitate statistical analysis. A reliable method to fabricate an array of 1024 CNT‐based sensors on a fully processed complementary‐metal‐oxide‐semiconductor microsystem is presented. A high‐yield process for the deposition of CNTs from a suspension by means of liquid‐coupled floating‐electrode dielectrophoresis (DEP), which yielded 80% of the sensor devices featuring between one and five CNTs, is developed. The mechanism of floating‐electrode DEP on full arrays and individual devices to understand its self‐limiting behavior is studied. The resistance distributions across the array of CNT devices with respect to different DEP parameters are characterized. The CNT devices are then operated as liquid‐gated CNT field‐effect‐transistors (LG‐CNTFET) in liquid environment. Current dependency to the gate voltage of up to two orders of magnitude is recorded. Finally, the sensors are validated by studying the pH dependency of the LG‐CNTFET conductance and it is demonstrated that 73% of the CNT sensors of a given microsystem show a resistance decrease upon increasing the pH value.