TBM掘进数据标准化预处理方法研究北大核心CSCD

TBM信息化采集了海量数据,对TBM数据的标准化预处理是进行诸多研究的前提。基于此,提出了一种TBM掘进数据标准化处理方法,依托TBM现场施工掘进大数据,以破岩特征为依据选取基本掘进参数(刀盘转速、推进速度、刀盘推力及刀盘扭矩)分析掘进过程TBM数据特点,提出循环掘进过程空推段、上升段、稳定段及下降段起点的判别方法,对稳定段起点提出了标准差法判别方法、均值判别方法、直方图判别方法,满足实时和非实时的数据划分需求。最后对两个TBM工程的数据进行标准化预处理,实现施工大数据的标准化。结果表明,提出的标准化预处理方法可实现循环掘进过程数据的有效划分。研究成果可推广应用于众多TBM工程的数据标准化处理,有效实现机器学习数据库的建立。     

An exploratory analysis of joint-activity participation characteristics using the American time use survey

This paper presents a detailed exploratory analysis of joint activity participation characteristics using the American Time Use Survey (ATUS). As a very large nationwide survey that explicitly elicited information on both household and non-household companions for each activity episode, the ATUS is ideally suited for this analysis. Several intuitive and interesting results are obtained. Joint episodes are found to be of longer durations, significantly likely to take place at the residence of other people, and often confined to certain time periods of the weekday. In addition, important differences in these characteristics are also observed based on activity purpose, companion type, and the day of the week. These findings are intended to provide the basis for the justification of detailed collection of joint activity–travel participation information in household activity–travel surveys, and also as a stimulant for further empirical analysis and modeling of joint activity participation behavior.

An experimental study of the effect of low-noise wheels in reducing noise and vibration

Wheel/rail interaction is a major source of railway noise. A low-noise wheel structure is developed and its effect on noise reduction is investigated. This low-noise wheel employs a rubber material inserted into the steel rim or mounted on the wheel surface. The low-noise wheel has low stiffness and a high-damping ratio compared to a solid wheel. Measurement shows that it reduces rolling and squealing. It turns out that a subway line with the proposed wheel could reduce its interior noise level by 4–5 dB(A) and vehicle vibration level by 7–8 dB. While the proposed structure seems promising in noise reduction for railway vehicles, the endurance and cost effectiveness of the low-noise wheel are yet to be verified.     

Persuasibility and its assessment

Persuasive technology is the use of computers, devices or applications to change a person’s attitudes or behavior. Persuasibility design within the system life-cycle is a nascent area of research which is different from design in the traditional method. This paper focuses on the research of persuasibility design and its assessment in the system life-cycle. A life-cycle oriented systemic general theory is developed in this paper to evaluate persuasibility design. Persuasibility assessment is considered as a part of persuasibility design. Its procedure and method are explored and analyzed based on the system life-cycle in this paper. A possible research direction is to create more explicit and detailed persuasion design and assessment methods which can be used not only in personal computer persuasive application, but also many other electric devices that are designed for persuasion purposes.     

Fuel economy comparison of conventional drive trains series and parallel hybrid electric step vans

A hybrid electric vehicle (HEV) is a vehicle that combines a conventional propulsion system with an on-board rechargeable energy storage system to achieve better fuel economy than a conventional vehicle HEVs do not have limited ranges like battery electric vehicles, which use batteries charged by an external source. The different propulsion power systems may have common subsystems or components. The objective of this study is to compare the fuel economies of a conventional step van, a series hybrid electric step van (HESV), and a parallel HESV by calculating the fuel consumption using the ADVISOR software by NREL. We also showed the results of the vehicles in different driving cycles including the Central Business District bus cycles, the New York City Cycle, and the US EPA City and Highway cycles.     

Analysis of a regenerative braking system for Hybrid Electric Vehicles using an Electro-Mechanical Brake

The regenerative braking system of the Hybrid Electric Vehicle (HEV) is a key technology that can improve fuel efficiency by 20∼50%, depending on motor size. In the regenerative braking system, the electronically controlled brake subsystem that directs the braking forces into four wheels independently is indispensable. This technology is currently found in the Electronic Stability Program (ESP) and in Vehicle Dynamic Control (VDC). As braking technologies progress toward brake-by-wire systems, the development of Electro-Mechanical Brake (EMB) systems will be very important in the improvement of both fuel consumption and vehicle safety. This paper investigates the modeling and simulation of EMB systems for HEVs. The HEV powertrain was modeled to include the internal combustion engine, electric motor, battery and transmission. The performance simulation for the regenerative braking system of the HEV was performed using MATLAB/Simulink. The control performance of the EMB system was evaluated via the simulation of the regenerative braking of the HEV during various driving conditions.     

Belt routing and safety assessment through computer simulation

Most of the research on safety belt systems has involved crash simulation that only considered a dynamic human model. However, belt routing analysis, usually known as comfort level estimation, is also an important factor in safety belt design, considering that serious injuries of the abdominal region result from the infiltration of a belt into the neck or the chest. Thus, safety belt evaluations using kinematic human models are also needed. In this paper, a belt fit simulation method is suggested. Using the proposed process, both comfort and safety analyses can be performed under the same conditions continuously, and thus the safety belt design parameters, such as the location of anchor points, dummy posture and etc., can be evaluated. In conclusion, this computer process enables a belt system design to reduce injuries.     

Development of an intelligent CAE system for auto-body concept design

The concept design phase is a critical step in auto-body design, as it has a great effect on later design work. This paper describes the implementation of an auto-body structure design in the early stages of a new auto-body developing program. In order to reduce the long design period and analysis error that plagues traditional auto-body concept design, an intelligent CAE system has been successfully developed and implemented based on the UGS NX/API opening platform. This system, the so-called ACD-ICAE (Auto-body concept design-intelligent computer aided engineering) System that means concept design-intelligent computer aided engineering system, employs a fully parametrized template method to build the conceptual auto-body geometry model and FEM model quickly and easily. It also integrates auto-body modeling, analysis and optimization on only one CAD platform via a parametric variables database. Moreover, all parametric variables are shared and updated in different phases of the ACD-ICAE System. A wizard User Interface (UI) based on knowledge of auto-body engineering was developed and used in this system. The procedures implementing the functional diagram of the ACD-ICAE system are also provided. A typical example of a car body concept design with four doors shows that the ACD-ICAE system is efficient and accurate.     

Theoretical method for predicting the weight reduction rate of a box-type car body for rolling stock by material substitution design

In this paper, a theoretical approach is suggested for predicting the structural performances and weight reduction rate of a car body with a box-type section when its material is substituted with a lightweight material for weight saving. For the material substitution design of a car body for rolling stock, bending, axial, and twisting deformations should be considered at constant stiffness and strength conditions. To compare the weight reduction effects on different material applications, some new indices were derived from a structural performance point of view. The derived indices provide good measures to estimate weight reduction by material substitution design and can be effectively applied to the conceptual design of a car body.     

Performance of air conditioners with a gas-liquid separation condenser and one-tank laminated evaporator

In this study, a parallel flow condenser and laminated evaporator for an automotive air-conditioning system were modified to improve performance. Gas-liquid separation type condensers, in which the condenser and receiver drier are integrated, and one-tank laminated type evaporators were developed, and their performances were investigated experimentally using HFC-134a. Heat transfer characteristics in the condenser are examined by means of air temperature, air velocity entering the condenser and inlet pressure of the refrigerant; heat transfer characteristics in the evaporator are examined by means of air temperature, relative humidity, flow rate of air, outlet pressure of refrigerant and superheat. Pressure drops for both evaporator and condenser are also measured, and correlations for pressure drop are derived for the condenser and evaporator, respectively. Air velocity and mass flow rate of the refrigerant have a significant effect on the overall heat transfer coefficient, and flow pass is not significantly influenced by the cooling capacity of the condenser. The overall heat transfer coefficient of the evaporator increases as air flow rate, air temperature and relative humidity increases.