bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parameters estimation for RL electrical circuits based on least square and Bayesian approach
Authors: Farnoosh R. , Nabati P. , Hajirajabi A. 
Published: March 2013

PurposeThe main purpose of this paper is to estimate the resistance and inductor in the RL electrical circuit when these are unavailable or missing data that it is a concern in electrical engineering. The input voltage is assumed to be corrupted by the noise and the current is observed at discrete time points.Design/methodology/approachThe authors propose a computationally efficient framework for parameters estimation using least square estimator and Bayesian Monte Carlo scheme.FindingsThe explicit formulas for least square estimator are derived and the strong consistency of resistance estimator is verified when inductor is a known parameter, then Bayesian estimation of parameters governed by using Markov chain Monte Carlo methods. The applicability of the results is demonstrated by using numerical examples. Several numerical results and figures are presented via Matlab and R programming to illustrate the performance of the estimators.Practical implicationsThe paper can be used in various types of electrical engineering real time projects. The projects include electrical circuits, electrical machines theory and drives, especially when the parameters are uncertain that it is a worry in electrical engineering.Originality/valueTo the author's best knowledge, least square and Bayesian estimation of resistance and inductor have not been studied before. The proposed model is nonlinear with respect to inductor (L); therefore the present work has fundamental difference in comparison with the similar models.
Finite element analysis of magnetostrictive vibration energy harvester
Authors: Rezaeealam Behrooz 
Published: March 2013

PurposeThe paper aims to analyze the behavior of the Galfenol rods under bending conditions that are employed in a vibration energy harvester by illustrating the spatial variations in stress and magnetic field.Design/methodology/approachThis paper describes a 3‐D static finite element model of magnetostrictive materials, considering magnetic and elastic boundary value problems that are bidirectionally coupled through stress and field dependent variables. The finite element method is applied to a small vibration‐driven generator of magnetostrictive type employing Iron‐Gallium alloy (Galfenol).FindingsThe 3‐D static finite element modeling presented here highlights the spatial variations in magnetic field and relative permeability due to the corresponding stress distribution in the Galfenol rods subjected to transverse load. The numerical calculations show that about 1.1 T change in magnetic flux density is achieved which demonstrates the effectiveness of the inspected vibration‐driven generator in voltage generation and energy harvesting. The model predictions agree with the experimental results and are coherent with the magnetostriction phenomenon.Originality/valueThis paper fulfils the behavior analysis of Galfenol rods under transverse load that includes both compression and tension. The compressive and tensile stresses contributions to change in magnetic flux densities in the Galfenol rods were calculated by which the effectiveness of the inspected vibration‐driven generator in voltage generation and energy harvesting is demonstrated.
A vertex cut algorithm for model order reduction of parasitic resistive networks
Authors: Kitanov Petko , Marcotte Odile , Schilders Wil H.A. , Shontz Suzanne M. 
Published: March 2013

PurposeTo simulate large parasitic resistive networks, one must reduce the size of the circuit models through methods that are accurate and preserve terminal connectivity and network sparsity. The purpose here is to present such a method, which exploits concepts from graph theory in a systematic fashion.Design/methodology/approachThe model order reduction problem is formulated for parasitic resistive networks through graph theory concepts and algorithms are presented based on the notion of vertex cut in order to reduce the size of electronic circuit models. Four variants of the basic method are proposed and their respective merits discussed.FindingsThe algorithms proposed enable the production of networks that are significantly smaller than those produced by earlier methods, in particular the method described in the report by Lenaers entitled “Model order reduction for large resistive networks”. The reduction in the number of resistors achieved through the algorithms is even more pronounced in the case of large networks.Originality/valueThe paper seems to be the first to make a systematic use of vertex cuts in order to reduce a parasitic resistive network.
Unified LCL circuit for modular active power filter
Authors: Wojciechowski Daniel 
Published: March 2013

PurposeThe purpose of this paper is to present the concept and design methodology for unified, LCL interfacing circuit intended for a high power, modular active power filtering system. The paper aims to contain simulations and selected measurements of an industry applied system.Design/methodology/approachThe design methodology of unified LCL circuit is based on an analytical model of the system and practical requirements for an active power filter. The stability of the system is confirmed by using poles of discrete transmittance of the close loop system.FindingsThe paper reveals the topology and design methodology of the unified LCL circuit for a high power, modular active power filtering system. The circuit permits zero current ripples, high dynamics of compensating currents, and full scalability of the system.Practical implicationsThe practical implications of this paper are in the industrial applications of high power, modular active filtering system.Originality/valueThe topology of unified LCL filter and its design methodology for a modular active power filtering system are of value. It also provides a stability analysis for the system with model‐based predictive current controller.
An OFDM‐based physical‐layer feedback mechanism for relay selection in virtual MIMO systems
Authors: Kuang Yujun , Zhang Enzhan 
Published: March 2013

PurposeThe purpose of this paper is to introduce an orthogonal frequency‐division multiplexing (OFDM)‐based 2‐phase physical‐layer feedback space (PFS) for distributed relay selection (RS) in virtual multiple‐input multiple‐output (VMIMO) systems. The proposed method is evaluated with numeric and simulation results.Design/methodology/approachUnlike minislots used in current MAC layer feedback, the authors introduce physical‐layer feedback space (PFS) which hosts one‐bit for each candidate relay (CR), for instance, a 48‐subcarrier OFDM symbol hosts 48 bits. In the two‐phase feedback procedure, each CR firstly hears the invitation and respond between cluster heads (CH) of upper‐/down‐stream cluster and decides whether to be a qualified relay or not. Then if it is qualified, it randomly selects one subcarrier and sends a pre‐equalized one‐bit feedback. The upper‐stream CH evaluate all feedbacks in PFS, then selects all or a subset of relays with successful feedback and broadcasts its decision to all nodes. Although the number of successful feedbacks (NSF) drops as number of CR increases (NCR), 7∼8 CR can be selected with high probability when NCR is triple that of total subcarriers (48).FindingsIn current literature, several traditional MAC layer feedback mechanisms are designed for relay selection in virtual MIMO (VMIMO) system most of which are based upon feedback minislots. For such methods, the number of active nodes should be estimated first and known to all participating nodes to choose optimal feedback possibility to obtain best successful feedback possibility. Furthermore, each minislot should include unique identification of candidate relay thus such methods can NOT be referred as one‐bit feedback. In the new method, though OFDM subcarriers play the same role as minislots, they are exactly one‐bit fashioned and occupies only multiple OFDM symbols which is much shorter than that in current methods.Originality/valueBy using physical‐layer feedback space, exactly only one‐bit is required for each candidate relay to send its feedback, and the overall overhead introduced for all of them is K‐bit provided by the required PFS, which spans only fixed duration of the PFS, which is one or more OFDM symbols. Therefore, the proposed scheme can greatly reduce overhead and feedback delay during relay selection.
Vector mode based hardware acceleration and emulation for LDPC application
Authors: Liao Y.B. , Han X. , Zhu Z.J. , Wang Y. , Kang S. 
Published: March 2013

PurposeWith the rapid development of integrated circuits, verification of SOC chips has become a great challenge due to its integration and complexity. Traditional software‐based simulation methodology cannot meet verification needs. Therefore, FPGA‐based hardware acceleration technologies are requested in SOC verification. The classic methodology of hardware acceleration downloads the DUT (Device under Test) to the FPGA, while part of RTL codes and test bench is still run on the simulator in the workstation. Research found that the speed bottleneck of this methodology is mostly caused by the ping‐pong mode of data transmission between workstation software and the FPGA emulator, thus resulting in that channel transmission time takes too much proportion of total time. The purpose of this paper is to present a vector mode based hardware/software co‐emulation methodology, which leverages a pipeline structure to transmit, receive and buffer data. This methodology reduces the communication overhead by carrying out a parallel mechanism in that while user's design is under test in the emulator, signal data are transmitting in the channel simultaneously, thus increasing the speed of hardware acceleration and emulation.Design/methodology/approachThe methodology of hardware acceleration proposed by this paper intercepts data for once from the emulation process of a traditional platform as test bench and utilizes direct memory access (DMA) channel to speed up data transfer, as well as increasing reasonable data caching mechanism, which reduces the ratio of channel transmission time in the entire emulation time, achieving accelerating emulation.FindingsThe proposed methodology and traditional hardware acceleration approach were tested on a quasi‐cyclic low‐density parity‐check (LDPC) decoder. Experiment results indicate that the proposed method can increase communication throughput 140 times compared with the traditional approach.Originality/valueA vector mode based hardware/software co‐emulation methodology is presented in the paper. Higher communication throughput can be achieved by carrying out a parallel mechanism, as well as leveraging a pipeline structure to transmit, receive and buffer data.
Accelerating data distribution in P2P live stream with data reservation mechanism
Authors: Liyong Ren , Ming Lei , Di Zhao 
Published: March 2013

PurposeThe purpose of this paper is to improve data transmission efficiency in a P2P system.Design/methodology/approachThis mechanism does not require changing existing mesh topology, and only necessary peers' evaluation mechanisms need to be introduced.FindingsThis paper presents a data reservation mechanism so that it can transmit data via the push and pull model on the P2P live stream system with the mesh topology. The experiment result of establishing a simulation environment reveals that the above mentioned is an effective way of reducing the data transmission delay by 40 per cent.Originality/valueTo improve data transmission efficiency in a P2P system, this paper presents a data reservation mechanism so that it can transmit data via the push and pull model on the P2P live stream system with the mesh topology.
Scalable group key exchange protocol with provable security
Authors: Li Chengbang , Xu Chunxiang 
Published: March 2013

PurposeThe purpose of this paper is to introduce a scalable group key exchange (GKE) protocol with provable security, which is used to establish a confidential channel.Design/methodology/approachThe protocol in this paper uses line structure, rather than formal ring structure or tree structure, to reduce the amount of calculation and communication.FindingsIn the protocol, every participant just need send two messages. The security can be proved under the Decisional Diffie‐Hellman (DDH) problem.Originality/valueUsing the protocol provides an efficient and secure method to allow group users to share a common key.
Research on resource allocation mechanism for MBMS in wireless cellular system
Authors: Cui Linli , Shao Zhenhai , Zhou Tian , Li Aiyun 
Published: March 2013

PurposeThe purpose of this paper is to introduce a resource allocation mechanism for Multimedia Broadcast/Multicast Service (MBMS) in a wireless cellular system and to obtain a rapid and efficient transmission scheme over various types' services. The proposed algorithm is evaluated by simulation results.Design/methodology/approachA big problem for wireless communication is the limited time/frequency resources. Therefore, the most important issue is how to utilize these limited resources to transmit various services over a wireless broadband network, especially for MBMS services. In this paper, resource allocation mechanism in a full unicast system is first analyzed with three classical methods, then improved modulation and coding schemes (MCS) methods are proposed in a full multicast system to improve system throughput and spectral efficiency. Based on the foregoing discussions, research on resource allocation mechanism for mixed multicast and unicast traffic is developed in single‐cell and multi‐cell system (MBSFN, MBMS over single frequency network), respectively. Different transmission proportions between multicast and unicast are analyzed and a multiplexing scenario is also considered.FindingsResource allocation is a hot topic in wireless communication and there are many investigations on it. However, resource allocation for multicast system, especially for mixed multicast and unicast traffic system, is still a problem worthy of further study. Under same transmission condition in a single cell scenario, system throughput in multicast mode is worse than in unicast mode, which is partly because the number of valid date in multicast resource block (RB) is less than the one in unicast in 3GPP LTE/LTE‐A, on the other hand, because that multicast need to select a relative low MCS to satisfy most MBMS users, even the users with a very poor transmission condition. Fortunately, multicast in MBSFN (MBMS over single frequency network) transfer mode can largely improve system performance.Originality/valueImproved MCS selection schemes are proposed for full multicast transmission and three transmission scenarios for mixed multicast and unicast traffic are presented to discuss resource allocation mechanism over various types' services. Simulation results show that system performance of multicast system can be greatly enhanced in MBSFN transmission mode, especially with MIMO technology.
The near‐field processing and narrowband imaging algorithm for MIMO array
Authors: Gong Pengcheng , Shao Zhenhai , Zhou Jingquan , Zhu Xueyong 
Published: March 2013

PurposeImaging is a really difficult problem when systems are implemented in the near‐field region and real‐time needs. The purpose of this paper is to consider a novel system model and present a narrowband 2‐D imaging algorithm in the near‐field region and under the real time constraint.Design/methodology/approachThe first part of this paper proposes a novel approximation for the round‐trip distance of the near‐field echoed data based on a 2‐D synthetic aperture planar array. The second part of this work proposes a near‐field narrow imaging algorithm based on the above system model. Narrowband waveforms are employed in the array system, so that the range alignment and decoupling in range‐azimuth are not necessary.FindingsThe errors of the proposed approximation are much smaller as compared with those of the Fresnel approximation. For example, the errors of the proposed approximation are negligible when the antenna is fixed at (0, 0). In other cases, the errors are decreased by almost 50 percent. Compared with 2‐D plane array, the synthetic aperture plane of the paper reduces the number of antennas. Finally, numerical simulation results verify the validity of the imaging algorithm.Originality/valueThe near‐field difficulty is solved by the adoption of the proposed approximation. The theoretical analysis and simulation results verify the validity of the imaging algorithm in the near‐field region and under the real time constraint.
A measurement of real travel speed for road segment with magnetic sensors
Authors: Zhang Enzhan , Kuang Yujun 
Published: March 2013

PurposeThe purpose of this paper is to introduce a weighted average method to process speed measurements from multiple magnetic sensors, which are installed on road segments. Speeds are weighted‐averaged in a fix duration time (5 minutes) for each sensor across location index of the sensor where it was installed. The proposed method is evaluated with numeric and simulation results.Design/methodology/approachUnlike traditional vehicle average speed measurements, the authors propose a weighted‐average speed measurement method of road segment, using wireless magnetic sensor nodes, which are installed on the measured road segment. Magnetic sensors offer a non‐contact vehicle detection method, and small sensors with relatively low power consumption. Using magnetic sensors, the local changes in the Earth's magnetic field caused by the presence of a moving vehicle can be measured and the vehicle's speed obtained. Next, using adaptive weighted average algorithm and space weighted algorithm in a fixed period, the weighted average travel speed of road segment can be obtained.FindingsIn current literature, there are many methods to measure vehicles' speed on road, such as image‐based, radar‐based, GPS‐based, double‐loop‐based or magnetic sensor‐based, but most of them only provide individual vehicle speed. Using probe vehicles, mean travel speed of road segment can be obtained, but it is costly on hardware and measurement, because many probe‐vehicles need to be used on roads and many measurements need to be done everyday. GPS data can be used to provide valuable travel speed data for Intelligent Transportation System (ITS). However, not every vehicle is equipped with GPS and to access ID numbers for personal cars would entail privacy problems. Mean travel speed of road segment is obtained based on statistical average speed. Generally, statistical average speed is used, which is based upon Gaussian distribution is not true in traffic systems.Originality/valueBy using wireless magnetic sensor nodes, vehicle instantaneous speeds are obtained in a fixed time when vehicles are passing over sensor nodes and then the adaptive weighted average speed on each sensor node location is computed based on the monitoring data from each sensor node in the fixed time. Considering different weights of each lane and road space (in the middle of the road segment or near the intersection), the proposed scheme can obtain the weighted‐average speed of the road segment.
Beyond price: how does trust encourage online group's buying intention?
Authors: Ku Edward C.S. 
Published: March 2013

PurposeThe purpose of this paper is to investigate how online trust affects group shopping intention in the Ihergo web site.Design/methodology/approachSamples from the Ihergo web site were collected by mailing a questionnaire survey to those who agreed to participate.FindingsGroup‐buying operators need to understand their consumers and the scheduling shopping rules between internet shoppers and firms. Moreover, word‐of‐mouth (WOM) can be created online by offering web visitors the ability to access the opinions of satisfied customers.Practical implicationsAn online business may adopt different methods to enhance its customer satisfaction level. When people enter a significant amount of personal data at a web site, they are typically reluctant to change vendors and enter the data again.Social implicationsCustomers view a group‐buying operator as a shopping expert, and expect that the group‐buying operator can handle shopping problems before a dispute occurs.Originality/valueThe findings of this study provide interesting insights for group‐buying operators interested in group‐buying commerce; consumers having a high level of interest in shopping possess a strong motivation and desire to interact with the group‐buying operator.
Public contributions to private‐collective systems: the case of social bookmarking
Authors: Benbunan‐Fich Raquel , Koufaris Marios 
Published: March 2013

PurposeThe aim of this study is to provide a theoretical extension to the private‐collective model of information sharing along with an empirical test with users of a social bookmarking website.Design/methodology/approachThe paper includes a survey of 112 users of an actual bookmarking site recruited through an online research panel firm. The survey consisted of scales adapted from the literature as well as scales developed by the authors.FindingsThe results indicate that contributions to a social bookmarking site are a combination of intentional and unintentional contributions. A significant predictor of intentional public contributions of bookmarks is an egoistic motivation to see one as competent by contributing valuable information. However, there is also a significant but negative relationship between altruism and public contribution whereby users concerned with the needs of others limit their public contributions.Research limitations/implicationsThe sample consists of users of a particular social bookmarking site (Yahoo!'s MyWeb). Therefore, the results may not be generalizable to other social bookmarking websites, different types of social networks, or other contexts lacking the public/private option for contributions. Second, since the data comes from a cross‐sectional survey, as opposed to a longitudinal study, the causal relations posited in the model and substantiated with the statistical analyses can only be inferred based on the authors’ theoretical development. Third, although the size of the sample (112 respondents) is appropriate for PLS analysis it may have been insufficient to detect other significant relationships.Practical implicationsAdministrators of social bookmarking sites should incorporate incentive and feedback mechanisms to inform contributors whether they contributions have been used (for example, with times viewed) and/or deemed useful (with numeric or qualitative ratings).Social implicationsThe results suggest that both selfish motivations associated with the need to feel competent (egoism), as well as selfless concerns for the needs of other users (altruism) drive intentional contributions to the public repository in social bookmarking systems. These two counterbalancing forces indicate that a mix of egoism and altruism is crucial for the long‐term sustainability of social web sites based on information sharing.Originality/valueThis study provides theoretical explanations and empirical evidence of egoism and altruism as significant explanations for cooperation in private‐collective models, such as the ones represented by social bookmarking systems.