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Magnetic properties and microstructures of snO_2 doped Mn-Zn ferrites

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Rare Metals 2006年第z1期25卷 445-449页

作者： NG foong-Kee sALE Frank R. school of Technology Tunku Abdul Rahman College PO Box 10979 50932 Kuala Lumpur West Malaysia school of Materials The University of Manchester Grosvenor Street Manchester M17HS United Kingdom

The effects of additive snO2 (0.4wt.%), with and without siO2 (0.02wt.%) and/or CaO (0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that snO2 on its own increases the initial permeability (μi) slightly, but snO2 with siO2 and/or CaO decreases the values of μi. However, ferrites with snO2 additions have reduced power losses. The separate contributions of hysteresis loss and eddy current loss to the total power loss show that snO2 (with or without siO2 and/or CaO) doping increases the hysteresis loss slightly, but snO2 doping alone reduces the eddy current loss significantly (～14%). The additions of siO2 or CaO further decrease the eddy current loss, and by interaction of snO2-CaO-siO2, the eddy current loss is reduced by more than 20%. These magnetic and microstructural effects were discussed in terms of the additive-impurity interaction, the existence of grain boundary phases, and the effective bulk and grain boundary resistivities of the ferrites.

关键词： Mn-Zn ferrites snO2 doping magnetic properties microstructure

Full Friendly Index sets of Cartesian Products of Two Cycles

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Acta Mathematica sinica,English series 2010年第7期26卷 1233-1244页

作者： Wai chee sHIU Department of Mathermatics Hong Kong Baptist University

Let G =（V, E） be a connected simple graph. A labeling f ： V → Z2 induces an edge labeling f＊： E → Z2 defined by f＊（xy） = f（x）＋f（y） for each xy ∈ E. For i ∈ Z2, let vf（i） = ｜f^-1（i）｜ and ef（i... 详细信息

Let G =（V, E） be a connected simple graph. A labeling f ： V → Z2 induces an edge labeling f＊： E → Z2 defined by f＊（xy） = f（x）＋f（y） for each xy ∈ E. For i ∈ Z2, let vf（i） = ｜f^-1（i）｜ and ef（i） = ｜f＊^-1（i）｜. A labeling f is called friendly if ｜vf（1） - vf（0）｜ ≤ 1. For a friendly labeling f of a graph G, we define the friendly index of G under f by if（G） = e（1） - el（0）. The set [if（G）｜ f is a friendly labeling of G} is called the full friendly index set of G, denoted by FFI（G）. In this paper, we will determine the full friendly index set of every Cartesian product of two cycles.

关键词： vertex labeling friendly labeling friendly index set Cartesian product of two cycles

An Efficient stacked-LsTM Based User Clustering for 5G NOMA systems

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Computers, Materials & Continua 2022年第9期72卷 6119-6140页

作者： s.Prabha Kumaresan chee Keong Tan Yin Hoe Ng Faculty of Engineering Multimedia UniversityCyberjaya63100Malaysia school of Information Technology Monash UniversitySubang Jaya47500Malaysia

Non-orthogonal multiple access(NOMA)has been a key enabling technology for the fifth generation(5G)cellular *** on the NOMA principle,a traditional neural network has been implemented for user clustering(UC)to maximize the NOMA system’s throughput performance by considering that each sample is independent of the prior and the subsequent ***,the prediction of UC for the future ones is based on the current clustering information,which is never used again due to the lack of memory of the ***,to relate the input features of NOMA users and capture the dependency in the clustering information,time-series methods can assist us in gaining a helpful insight into the *** its mathematical complexity,the essence of time series comes down to examining past behavior and extending that information into the ***,in this paper,we propose a novel and effective stacked long short term memory(s-LsTM)to predict the UC formation of NOMA users to enhance the throughput performance of the 5G-based NOMA *** the proposed strategy,the s-LsTM is modelled to handle the time-series input data to improve the predicting accuracy of UC of the NOMA users by implementing multiple LsTM layers with hidden *** implemented LsTM layers have feedback connections that help to capture the dependency in the clustering information as it propagates between the ***,we develop,train,validate and test the proposed model to predict the UC formation for the futures ones by capturing the dependency in the clustering information based on the time-series *** results demonstrate that the proposed scheme effectively predicts UC and thereby attaining near-optimal throughput performance of 98.94%compared to the exhaustive search method.

关键词： Non-orthogonal multiple access(NOMA) deep neural network(DNN) long short term memory(LsTM) temporal channel user clustering

super-edge-graceful Labelings of some Cubic Graphs

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Acta Mathematica sinica,English series 2006年第6期22卷 1621-1628页

作者： Wai chee sHIU Department of Mathematics Hong Kong Baptist University

The notion of super-edge-graceful graphs was introduced by Mitchem and simoson in ***, few examples except trees are known. In this paper, we exhibit two classes of infinitely many cubic graphs which are super-edge-gr... 详细信息

关键词： super-edge-graceful cubic graph permutation cubic graph permutation Petersen graph,permutation ladder graph

Distance signless Laplacian spectrum of a graph

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Frontiers of Mathematics in China 2022年第4期17卷 653-672页

作者： Huicai JIA Wai chee sHIU College of science Henan University of EngineeringZhengzhou451191China Department of Mathematics The Chinese University of Hong KongHong KongChina

Let G be a simple connected graph with n *** transmission Tv of a vertex v is defined to be the sum of the distances from v to all other vertices in G,that is,T_(v)=Σ_(u)∈Vd_(uv),where duv denotes the distance between u and *** T_(1),…,T_(n)be the transmission sequence of *** D=(dij)_(n×n)be the distance matrix of G,and T be the transmission diagonal matrix diag(T_(1),…,T_(n)).The matrix Q(G)=T+D is called the distance signless Laplacian of *** this paper,we provide the distance signless Laplacian spectrum of complete k-partite graph,and give some sharp lower and upper bounds on the distance signless Laplacian spectral radius q(G).

关键词： Distance signless Laplacian spectral radius bound

An integrated approach for machine-learning-based system identification of dynamical systems under control:application towards the model predictive control of a highly nonlinear reactor system

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Frontiers of Chemical science and Engineering 2022年第2期16卷 237-250页

作者： Ewan chee Wee Chin Wong Xiaonan Wang Department of Chemical&Biomolecular Engineering Faculty of EngineeringNational University of SingaporeSingapore 117585Singapore Chemical Engineering&Food Technology Cluster Singapore Institute of TechnologySingapore 138683Singapore

Advanced model-based control strategies,e.g.,model predictive control,can offer superior control of key process variables for multiple-input multiple-output *** quality of the system model is critical to controller performance and should adequately describe the process dynamics across its operating range while remaining amenable to fast *** work articulates an integrated system identification procedure for deriving black-box nonlinear continuous-time multiple-input multiple-output system models for nonlinear model predictive *** showcase this approach,five candidate models for polynomial and interaction features of both output and manipulated variables were trained on simulated data and integrated into a nonlinear model predictive controller for a highly nonlinear continuous stirred tank reactor *** procedure successfully identified system models that enabled effective control in both servo and regulator problems across wider operating *** controllers also had reasonable per-iteration times of ca.0.1 *** demonstration of how such system models could be identified for nonlinear model predictive control without prior knowledge of system dynamics opens further possibilities for direct data-driven methodologies for model-based control which,in the face of process uncertainties or modelling limitations,allow rapid and stable control over wider operating ranges.

关键词： nonlinear model predictive control black-box modeling continuous-time system identification machine learning industrial applications of process control

UAV navigation system using line-based sensor pose estimation

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Geo-spatial Information science 2018年第1期21卷 2-11页

作者： Julien Li-chee-Ming Costas Armenakis Department of Earth and space science and Engineering Geomatics EngineeringLassonde School of EngineeringYork UniversityTorontoCanada

This work presents a mapping and tracking system based on images to enable a small Unmanned Aerial Vehicle(UAV)to accurately navigate in indoor and GPs-denied outdoor environments.A method is proposed to estimate the UAV’s pose(i.e.,the 3D position and orientation of the camera sensor)in real-time using only the on-board RGB camera as the UAV travels through a known 3D environment(i.e.,a 3D CAD model).Linear features are extracted and automatically matched between images collected by the UAV’s onboard RGB camera and the 3D object *** matched lines from the 3D model serve as ground control to estimate the camera pose in real-time via line-based space *** results demonstrate that the proposed modelbased pose estimation algorithm provides sub-meter positioning accuracies in both indoor and outdoor *** is also that shown the proposed method can provide sparse updates to correct the drift from complementary simultaneous localization and mapping(sLAM)-derived pose estimates.

关键词： Pose estimation modelbased tracking navigation GPs-denied environment

synthesis of tin nanoparticles through modified polyol process and effects of centrifuging and drying on nanoparticles

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中国有色金属学会会刊：英文版 2012年第S3期22卷 707-711页

作者： sang-soo chee Jong-Hyun LEE Department of Materials science and Engineering Seoul National University of Science and Technology

sn nanoparticles with average diameter of 13.1 nm were synthesized by modified polyol process,and their melting point was observed to be about 40 °C less than that of bulk *** though sn nanoparticles are solid and covered with thin PVP capping and oxide layer,sn nanoparticles in solution agglomerate upon centrifugation,resulting in a melting point *** to stickiness of the PVP capping layer,extensive aggregation between sn nanoparticles was observed after ***,the aggregation behavior did not further influence the melting point,because actual agglomeration did not occur in the aggregates.

关键词： tin nanoparticle melting point centrifugation agglomeration aggregation

L(j,k)-number of Direct Product of Path and Cycle

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Acta Mathematica sinica,English series 2013年第8期29卷 1437-1448页

作者： Wai chee sHIU Qiong WU Department of Mathematics Hong Kong Baptist University

For positive numbers j and k, an L（j,k）-labeling f of G is an assignment of numbers to vertices of G such that ｜f（u）-f（v）｜≥j if uv∈E（G）, and ｜f（u）-f（v）｜≥k if d（u,v）=2. Then the span of f is the difference between the maximum and the minimum numbers assigned by f. The L（j,k）-number of G, denoted by λj,k（G）, is the minimum span over all L（j,k）-labelings of G. In this paper, we give some results about the L（j,k）-number of the direct product of a path and a cycle for j≤k.

关键词： L(j k)-labeling product of a path and a cycle