Order selection criteria for vector autoregressive models

The least-squares method for estimating the parameters of the vector autoregressive (VAR) model is considered and new estimates for the covariance matrix of the VAR model input noise and the prediction error covariance matrix are derived. Based on these new estimates, the criteria FPEF and AICF for VAR model order selection are proposed. FPEF can replace the final prediction error (FPE) criterion, and AICF, which is an estimate of the Kullback-Leibler index, can replace the Akaike information criterion (AIC) and its corrected version AICC. A simulation study shows that FPEF is less biased than FPE, and AICF is less biased than AIC and AICC. In addition, the performance of the proposed criteria is compared with that of other well-known criteria and the results show that AICF has the best performance and gives the smallest average prediction error.     

Asymptotic performance of transmit antenna selection with maximal-ratio combining for generalized selection criterion

In this letter, we investigate the asymptotic error performance of an uncoded multiple-input-multiple-output (MIMO) scheme combining transmit antenna selection and receiver maximal-ratio combining (MRC) with a generalized selection criterion. A single transmit antenna corresponding to a fixed ordinal number of order statistic is selected for uncoded transmission. The order statistics consist of instantaneous channel power gain between each transmit and all the receive antennas. A general asymptotic bit error rate (BER) expression is derived for all values of ordinal number. An interesting conclusion is reached that the system diversity order is proportional to the ordinal number of the selected antenna.     

Part assessment guidelines and criteria for parts selection andmanagement

Parts selection and management is a process designed to evaluate the risks inherent in the use of an electronic part (e.g., a resistor, diode, or integrated circuit), and then facilitate informed decisions regarding its selection and future management activities. One step in the process is part assessment, which evaluates a part's quality and integrity. This involves comparing data acquired for the part with predetermined criteria to determine if the part will function acceptably in an equipment manufacturer's product. This paper presents the part assessment process, along with the criteria developed for assessment. The process and criteria were developed by analyzing industry standards and existing company methods, consulting with industry and academia experts, and conducting a case study of 113 electronic parts. The results of the case study are also provided     

On WCDMA base station selection criteria

This letter presents a BS selection criterion for WCDMA that allows selecting the base station requiring the minimum transmission power in both the uplink and downlink direction. The importance of minimizing transmitted power lies on the associated interference reduction and, consequently, the capacity increase. Furthermore, it is shown that, with a proper setting of the parameters, the criterion used in practical WCDMA systems based on Ec/Io measurements can be adjusted to provide results similar to the proposed method.     

Variable structure Human Intention Estimator with mobility and vision constraints as model selection criteria

In this paper, a novel method for early estimation of a human’s action intention is presented. Human intention, modeled as a goal location associated with a hand motion and eye gaze dynamics, is inferred by fusing information from collected hand motion and gaze motion data. The algorithm, called Human Intention Estimator with Variable Structure (HIEVS), uses two variable structure Interacting Multiple Model (VS-IMM) filters in parallel to process the hand motion and gaze data and generate posterior model probabilities associated with a finite set of action models. The posterior model probabilities from each filter are then fused at the end of each iteration and the current intention is estimated as the model, which has the highest fused posterior model probability. Two model set augmentation (MSA) algorithms are presented to select the active models for each VS-IMM during each iteration. For the hand motion filter, an MSA algorithm which computes the human’s reachable workspace is used. The MSA algorithm for the gaze filter utilizes the human’s visual span to determine the active models. This method allows for accurate early prediction of the human’s intention even when the total model set is large. A real world experiment is performed to validate the proposed method.     

Recombination level selection criteria for lifetime reduction in integrated circuits

In the past, lifetime control in integrated circuits has been done on an empirical basis. This paper introduces selection criteria for recombination centers which are to be used for reducing minority carrier lifetime in integrated circuits. It is shown that the recombination level should have a large lifetime ratio (τ_SC/τ_LL) in order to obtain minority carrier lifetime reduction with minimal increase in the leakage current, and should possess large capture cross section values in order to minimize compensation effects. Using these criteria, preferred locations for the recombination center have been defined for both p and n type silicon, and the trade-off between reduction of lifetime and increase in leakage current has been shown to degrade with increase in resistivity and ambient temperature. These criteria have also allowed a quantitative comparison between various lifetime control techniques for the first time, and platinum doping has been identified as the most favorable lifetime control process at the present time.     

Joint antenna subset selection for spatial multiplexing systems based on statistical and instantaneous selection criteria

While the joint transmit/receive (Tx/Rx) AnSS with exhaustive search is the best solution for error rate minimization, its complexity makes it difficult for implementation on practical systems. To overcome this disadvantage, we propose a two-stage AnSS algorithm for the spatial multiplexing (SM) in the multiple input multiple output (MIMO) system, which employs both the statistical (i.e., average Euclidean distance, AED) and instantaneous selection criteria (i.e., modified instantaneous Euclidean distance, M-IED). The proposed algorithm reduces the computational complexity by decoupling the joint Tx/Rx selection into two separate selections of the numbers of Tx/Rx antennas and antenna subset, respectively. We show that the proposed AED criterion can be implemented through a simple look up table (LUT), thereby significantly reducing the computational complexity. Simulation results and computational complexity comparisons, prove that the proposed two-stage AnSS algorithm for the SM scheme reduces the hardware and computational complexity without any loss of the signal-to-noise ratio (SNR) and the diversity order, compared to the exhaustive search method.     

Contractor selection criteria: a cost-benefit analysis

This paper describes an empirical study aimed at ranking prequalification criteria on the basis of perceived total cost-benefit to stakeholders. A postal questionnaire was distributed to 100 client and contractor organizations in Australia in 1997. Forty-eight responses were analyzed for scores on 38 categories of contractor information in terms of “value to client” “contractor costs,” “client costs,” and “value for money.” The client and contractor responses for “value to client” and “client costs” of processing were found to be homogeneous. Those for “contractor costs” and “value for money” differed significantly between the clients and the contractors. A simple linear regression analysis was used to model the responses, and an index of cost-benefit was derived for each of the categories. This was found to be superior to all of the nonlinear alternatives examined. The model was also found to have greater intuitive value than the equivalent raw “value for money” responses     

Bias criteria for the selection of spectral windows (Corresp.)

Bias criteria for evaluating spectral window functions and upper bounds of bias are derived using power spectrum models, and known window functions are evaluated according to the criteria. The function commonly called the "Hanning" window is shown to have the best bias characteristics.     

Truncation criteria for model reduction using balanced realisation

It is shown with an example that the reduction technique using balanced realisation suggested previous (Moore 1981) may not retain the most significant states. An example is presented which shows that there are cases where the truncation of states using the second-order modes instead of d_i (products of the second-order modes and the input or output vector of the balanced realisation) leads to better approximation of the impulse response     

Analytical model for design criteria of passively Q-switched lasers

A general and straightforward model was developed for the design of passively Q-switched lasers. With the second-threshold criterion and using a numerically fitting procedure, the output pulse energy was expressed as an analytical function of the initial transmission of the saturable absorber and the reflectivity of the output coupler. An analytical expression for the optimal output reflectivity was also obtained for maximizing the output pulse energy of a passively Q-switched laser with a given initial transmission of the saturable absorber. Excellent agreement was studied between the present results and detailed theoretical computations. A Nd:YAG laser with Cr⁴⁺ :YAG as a saturable absorber has illustrated the use of the present model     

Active overload prevention based adaptive MAP selection in HMIPv6 networks

Multi-level mobile anchor points (MAP) architecture is deployed in large-scale wireless/mobile networks using HMIPv6 to achieve better mobility service, while selecting the most suitable serving MAP for the mobile nodes (MNs) to enhance the whole network performance has been a critical issue. An adaptive MAP selection based on active overload prevention (MAP-AOP) hence is proposed. The MAP periodically evaluates the load status by using dynamic weighted load evaluation algorithm, and then sends the load information to the covered access routers (AR) by using the expanded routing advertisement message in a dynamic manner. Taking achieving the load balancing among the available MAPs, the current serving AR executes the active overload prevention to select MAP candidates for the MN pending a handover, and then adaptively selects an optimal one from the candidates by comprehensively considering the system cost and the average handover latency caused by each candidate. The simulation conducted on the NS-2 platform indicates that MAP-AOP outperforms the comparative MAP selection schemes with the optimized system cost and average handover latency, and better load balancing.     

Bid markup selection models by use of multiple criteria

Multiple attribute decision modeling is proposed for determining the most preferred bid markup in a competitive bidding situation. In this note, a previously proposed model is extended by introducing two new bidding criteria, called the conditional positive profit and the expected positive profit ratios, respectively. Three two-criteria decision models and a single criteria decision models using the newly introduced criteria are proposed to determine the bidder's most preferred markup level. The simple additive weighting method and the weighting product method are used to solve these models. Two numerical examples are used to illustrate the different rankings that are obtained when different models and solution methods are used. The results demonstrate that the bidder's preference over the set of bidding criteria has a significant effect on the selection of the bid markup     

On the residual variance and the prediction error for the LSF estimation method and new modified finite sample criteria for autoregressive model order selection

The case where the data sample size is finite and the least-squares-forward (LSF) method is used for autoregressive (AR) parameter estimation is considered. New formulas describing the residual variance and the prediction error behaviors in AR parameter estimation are derived, and the relation between the residual variance and the prediction error is determined. Based on this relation, the existing finite sample criteria for AR model order selection are modified, and it is shown that these modified criteria have better performance.     

Asymptotic performance of space-time block codes with imperfect transmit antenna selection

The asymptotic bit error performance of the Alamouti scheme with transmit antenna selection is investigated for imperfect selection of antenna subset. It is shown that the transmit diversity order is equal to the largest ordinal number of the antenna within the selected antenna subset.     

异构网络选择的一种新博弈模型

目前对于异构网络选择问题的研究大多没有充分考虑用户和网络的相互选择,为此提出一种新的异构网络选择博弈模型,通过用户与网络相互选择得到该博弈的稳定匹配.算法性能分析与仿真验证表明,该模型相对于用户决策模型提高了网络满意度,相对于网络决策模型提高了用户满意度,即最终用户与网络得到了双赢.     

A hybrid approach of neutrosophic sets and DEMATEL method for developing supplier selection criteria

For any organization, the selection of suppliers is a very important step to increase productivity and profitability. Any organization or company seeks to use the best methodology and the appropriate technology to achieve its strategies and objectives. The present study employs the neutrosophic set for decision making and evaluation method (DEMATEL) to analyze and determine the factors influencing the selection of SCM suppliers. DEMATEL is considered a proactive approach to improve performance and achieve competitive advantages. This study applies the neutrosophic set Theory to adjust general judgment, using a new scale to present each value. A case study implementing the proposed methodology is presented (i.e. selecting the best supplier for a distribution company). This research was designed by neutrosophic DEMATEL data collection survey of experts, interviewing professionals in management, procurement and production. The results analyzed in our research prove that quality is the most influential criterion in the selection of suppliers.     

基于MAP的多态自适应NEMO模型

为实现对移动网络(NEMO)的高效支持,提出了基于MAP的多态自适应NEMO模型,根据节点组成情况将NEMO分为三种状态:稳态、亚稳态、活跃态,结合移动IPv6、MAP及前缀绑定更新实现对三态的自适应支持,并设计多态NEMO通信优化算法对NEMO与外界的通信过程进行优化,提高了NEMO的整体通信效率。