Effects of injection parameters on propagation patterns of hydrogen-fueled rotating detonation waves

Two-dimensional rotating detonation waves (RDWs) with separate injections of hydrogen and air are simulated using the Navier–Stokes equations together with a detailed chemical mechanism. The effects of injection stagnation temperature and slot width on the detonation propagation patterns are investigated. Results find that extremely high temperatures can lead to a chaotic mode in which detonation waves are generated and extinguished randomly. Increasing the slot width can reduce the number of detonation waves and finally trigger detonation quenching at a low injection stagnation temperature. But increasing the slot width can change the RDW propagation pattern from a chaotic to a stable mode under high injection temperature. Furthermore, the kinetic parameter τ (representing the chemical reactivity of the mixture) and the kinematic parameter α (representing the mixing efficiency of hydrogen and oxygen) are introduced to distinguish the RDW propagation patterns.     

Trust based consensus model for social network in an incomplete linguistic information context

A theoretical framework to consensus building within a networked social group is put forward. This article investigates a trust based estimation and aggregation methods as part of a visual consensus model for multiple criteria group decision making with incomplete linguistic information. A novel trust propagation method is proposed to derive trust relationship from an incomplete connected trust network and the trust score induced order weighted averaging operator is presented to aggregate the orthopairs of trust/distrust values obtained from different trust paths. Then, the concept of relative trust score is defined, whose use is twofold: (1) to estimate the unknown preference values and (2) as a reliable source to determine experts’ weights. A visual feedback process is developed to provide experts with graphical representations of their consensus status within the group as well as to identify the alternatives and preference values that should be reconsidered for changing in the subsequent consensus round. The feedback process also includes a recommendation mechanism to provide advice to those experts that are identified as contributing less to consensus on how to change their identified preference values. It is proved that the implementation of the visual feedback mechanism guarantees the convergence of the consensus reaching process.     

X线能谱中重叠峰的处理

回顾了Ｘ线能谱中重叠峰的处理方法，本文述及重叠系数法和退卷积法。阐述了重叠峰的概念、重叠系数的计算和测量方法以及强度的计算。介绍了方法的原理，并列举了具体实例。     

基于线路分段参数的非全程同塔双回线故障定位算法

对非全程同塔双回输电线路故障定位问题进行研究。首先,对非全程同塔双回线的特点进行分析,并针对传统伪根识别法无法适用于非全程同塔双回线故障定位的问题,在分析伪根存在与否的基础上,提出一种换模量伪根识别算法,该算法可以有效识别故障支路与非故障支路的伪根情况。进而,提出一种基于非全程同塔双回线路分段参数的双端工频量故障定位算法,该算法将故障支路辨识与故障点定位相结合,在线路全程内均可完成故障定位,不受故障类型、各端数据不同步和过渡电阻等因素影响。ATP-EMTP仿真结果表明,所提算法可行、有效。     

Notices

The expected number of maxima and level crossings of a continuous stationary Gaussian process and the discrete process obtained by sampling the continuous one are evaluated and compared. The ratio of these two values as a function of sampling rate for two classes of spectra is calculated. It is shown that the rule of thumb of sampling at twice the Nyquist frequency is a good one.     

Factorial 2 p–q Plans Robust Against Linear and Quadratic Trends

When the substrate of a 2 ^n–q factorial or fractional factorial experiment may be expected to show trends representable by linear and quadratic terms in time, then certain orderings spaced at equal time-intervals permit better estimation of the effects than do others. Some of these ordered plans are given for p – q = 2, 3, 4, 5. Simple methods are given for computing effects, trends, and efficiencies.     

Quantitative analysis of time-course development of motion sickness caused by in-vehicle video watching

It has been common and popular to watch videos in moving vehicles. An important issue in developing comfortable in-vehicle video watching systems is to understand how passengers get motion sickness. With this in mind, the goals of this paper are (1) to introduce an experimental protocol and a statistical analysis procedure for quantitatively evaluating how motion-sickness is developed during car-driving, and (2) to demonstrate their practical usefulness with a working experimental study. In the experimental protocol, motion sickness was induced to subjects by requiring them to watch an in-vehicle video during 15-min driving, and the time-course development of motion sickness was recorded by asking subjects to evaluate their degree of motion sickness every one minute. A main difficulty in analyzing data from these studies is how to incorporate the individual difference in motion-sickness susceptibility. Since susceptibilities are markedly different among subjects, within-subject design experiments are preferred. However, it is practically difficult to conduct complete set of trials because subjects who are not willing to continue experiment (due to heavy motion sickness) should be able to withdraw from the subsequent series of trials in accordance with ethical requirement. To cope with this incomplete data issue, we introduce a statistical data analysis procedure that enables to estimate and impute missing entries in the within-subject design table. Using a working example, we demonstrated that the protocol and the procedure are useful for quantitative assessment of the time-course motion sickness development. We conducted an in-vehicle motion-sickness study with 31 subjects, where the time-course motion sickness developments of video-watching, book-reading, and normal riding conditions were compared. The results indicate that video-watching brings on 2.7 times more severe motion sickness than normal riding, but 25% less severe than book-reading.     

A Balanced Design for 18 Varieties

A solution is given to the problem of finding a balanced incomplete block design for 18 varieties in 51 blocks of six plots each. The design is obtained by combining group divisible partially balanced designs and duplicating some of the blocks.     

An approach to group decision making with heterogeneous incomplete uncertain preference relations

For practical group decision making problems, decision makers tend to provide heterogeneous uncertain preference relations due to the uncertainty of the decision environment and the difference of cultures and education backgrounds. Sometimes, decision makers may not have an in-depth knowledge of the problem to be solved and provide incomplete preference relations. In this paper, we focus on group decision making (GDM) problems with heterogeneous incomplete uncertain preference relations, including uncertain multiplicative preference relations, uncertain fuzzy preference relations, uncertain linguistic preference relations and intuitionistic fuzzy preference relations. To deal with such GDM problems, a decision analysis method is proposed. Based on the multiplicative consistency of uncertain preference relations, a bi-objective optimization model which aims to maximize both the group consensus and the individual consistency of each decision maker is established. By solving the optimization model, the priority weights of alternatives can be obtained. Finally, some illustrative examples are used to show the feasibility and effectiveness of the proposed method.     

Levels of incomplete information in group decision models – A comprehensive simulation study

We present a comprehensive computational study on the effects of providing different forms of incomplete preference information in additive group decision models. We consider different types of information on individual preferences, and on weights of the group members, and study their effects on conclusiveness, efficiency and fairness of outcomes at the group level. Furthermore, we analyze possible violations of the axiom of independence of irrelevant alternatives (IIA) as well as the impact of problem characteristics, in particular initial agreement between group members. Our results indicate that providing information in the form of a ranking of differences between consecutive alternatives comes close to providing exact cardinal preference information in several outcome dimensions. However, group decision procedures based on incomplete preference information also show a significant amount of violations of the IIA axiom.