对高职院校学生体育运动参与情况的调查研究

本文运用文献资料法、调查法和数理统计法等研究方法,对高职院校学生体育运动参与情况进行了调查研究。旨在通过调查,了解高职院校学生的运动参与状况,为改善高职院校学生运动参与现状及提高高职院校学生的运动参与水平提供借鉴和参考。     

山区河流泥石流灾害防治技术研究

为改善通航条件、提高航道等级,对山区河流泥石流灾害防治技术进行了研究.根据形成机理、运动规律、成灾机制、岸坡的地形地貌特点,把山区河流型泥石流分为坡面流和沟谷流;基于土质结构原理与岩土稳定理论,提出了修复植被、规范人类行为与截流排水、拦粗排细、转向导流等工程防治技术相结合的山区河流泥石流灾害的综合防治技术.结果表明,该...     

电沉积Ni-S、Ni-Co-S合金析氢阴极的研究

在电沉积法制备Ni-S合金电极的基础上,向镀液中添加硫酸钴制备了Ni-Co-S合金电极。电化学测试结果表明,Ni-Co-S合金电极和Ni-S合金电极的催化性能都要好于其它电极,Ni-Co-S合金电极的性能随着硫酸钴浓度的升高先升高后降低。计算了电极的电极反应动力学参数(包括Tafel斜率b、交换电流密度i0和过电位),解释了Ni-Co-S合金电极和Ni-S合金电极在不同电流密度区活性不同的原因。恒电流电解表明,Ni-Co-S合金电极具有较高的稳定性。电极的微观形貌用SEM进行表征,成份用能谱进行分析,X射线衍射分析电极的晶型结构。     

Estimating a model of dynamic activity generation based on one-day observations: Method and results

In this paper we develop and explore an approach to estimate dynamic models of activity generation on one-day travel-diary data. Dynamic models predict multi-day activity patterns of individuals taking into account dynamic needs as well as day-varying preferences and time-budgets. We formulate an ordered-logit model of dynamic activity-agenda-formation decisions and show how one-day observation probabilities can be derived from the model as a function of the model’s parameters and, with that, how parameters can be estimated using standard loglikelihood estimation. A scale parameter cannot be identified because information on within-person variability is lacking in one-day data. An application of the method to data from a national travel survey illustrates the method. A test on simulated data indicates that, given a pre-set scale, the parameters can be identified and that estimates are robust for a source of heterogeneity not captured in the model. This result indicates that dynamic activity-based models of the kind considered here can be estimated from data that are less costly to collect and that support the large sample sizes typically required for travel-demand modeling. We conclude therefore that the proposed approach opens up a way to develop large-scale dynamic activity-based models of travel demand.     

基于动态控制的船舶制造成本反馈系统

成本失控是制约船舶企业竞争力的关键因素.为实现成本的动态控制,要求成本反馈系统能够及时、经济地提供准确的产品成本信息.为适应船舶制造成本反馈的特殊需求,对作业成本法进行了三点改进:统一了直接成本和间接成本处理方式、以广义工作中心进行成本归集和分配、合并了成本动因.算例表明改进的作业成本法计算出的产品成本准确性介于传统的成本核算方法和作业成本法之间,且贴近作业成本法.     

Rural transport – Valuing the mobility of older people

This paper describes a series of focus groups that were undertaken in the Republic of Ireland and Northern Ireland to examine the challenges faced by older people in rural Ireland when trying to make trips. The paper outlines transport policy in both Northern Ireland and the Republic of Ireland and describes the activity patterns of older trip makers and the modes they use. It also discusses some of the contrasts between challenges faced by older men and older women. Both older men and older women experience a shrinking in activity spaces and activity participation when older. Older women are less likely to drive and to own a car and so are seriously impacted by loss of a spouse in terms of their unmet travel needs. However, older men also experience difficulties: the alternatives that are available (such as community transport schemes) provide trips and services that are more attractive to women. In addition, the car dependent lifestyles of men throughout their adult lives seems to make them less prepared for life without a car than older women.     

Attitudes of Hong Kong residents to cars and public transport: Some policy implications

Hong Kong currently has low levels of car ownership and use due to a combination of good public transport, high population densities and high private transport costs. However, levels are rising, contributing to congestion and environmental problems. A major response by the government is to seek to increase rail's share of public transport journeys from its current level of 33% to 45% by 2016. After reviewing the transport situation in Hong Kong, the paper discusses the appropriateness of these targets as well as questioning whether they are achievable. The results of a questionnaire survey of 595 residents of Hong Kong, designed to elicit people's attitudes to cars and public transport, are analysed. It is concluded that unless the government does more to curb car ownership and use, rail targets will have little chance of being achieved.     

Characteristics of operating mode distributions of light duty vehicles by road type,average speed,and driver type for estimating on-road emissions: Case study of Beijing

Abstract

Researchers have collected extensive vehicle activity data in Beijing using GPS and attempted to develop a comprehensive database of facility- and speed-specific operating mode (OpMode) distributions of various vehicle types for estimating on-road vehicle emissions. This study developed the specific OpMode distributions of light duty vehicles (LDVs) for both restricted access and unrestricted access road types at various average speeds for characteristic analysis. (1) Strong patterns are found in the variations in OpMode distributions with the increase in the average speed: the time fraction of Decelerating/Braking remains less than 7%. The fraction of Idling decreases dramatically from 95% to 0%, while the fraction of Cruising/Accelerating increases from 2% to 94%. The fraction of Coasting increases to 28% and then decreases. (2) The time fractions for restricted access and unrestricted access are significantly different at the same average speeds, especially in Operating Modes #0, #1, #11, #12, #13, #14, #21, and #22, possibly causing an error of 20% in the emissions estimations. (3) Taxis show different OpMode distributions than those for private cars in the operating modes of Decelerating/Braking, Idling, and high-VSP modes, especially at low average speeds. The differences are derived from the more skillful driving behaviors of taxi drivers and may cause an estimation error of over 10%. Thus, the activities of taxis and private cars should be modeled separately for on-road emissions estimations.     

Unraveling the relationship between trip chaining and mode choice: evidence from a multi-week travel diary

Abstract

Trip chaining (or tours) and mode choice are two critical factors influencing a variety of patterns of urban travel demand. This paper investigates the hierarchical relationship between these two sets of decisions including the influences of socio-demographic characteristics on them. It uses a 6-week travel diary collected in Thurgau, Switzerland, in 2003. The structural equation modeling technique is applied to identify the hierarchical relationship. Hierarchy and temporal consistency of the relationship is investigated separately for work versus non-work tours. It becomes clear that for work tours in weekdays, trip-chaining and mode choice decisions are simultaneous and remain consistent across the weeks. For non-work tours in weekdays, mode choice decisions precede trip-chaining decisions. However, for non-work tours in weekends, trip-chaining decisions precede mode choice decisions. A number of socioeconomic characteristics also play major roles in influencing the relationships. Results of the investigation challenge the traditional approach of modeling mode choice separately from activity-scheduling decisions.     

Analysis of within-household effects and between-household differences in maintenance activity allocation

This paper investigates the allocation of household individuals to out-of-home maintenance activities using the rich activity-travel diary data from the San Francisco Bay Area. Two inter-related decisions are considered in this context: (i) whether the given activity episode is performed individually (solo) or jointly, and (ii) the person who participates in the activity, if it is a solo activity. To account for the conditional nature of the solo activity person selection, a nested mixed logit modeling framework is proposed and implemented to jointly analyze person allocation for all maintenance activities performed by a household on a given day. The model is used to investigate within-household effects and between-household differences. The proposed model relaxes some important restrictions in person allocation models by accounting for various sources of correlations and relaxing the assumption of constant variance across households. The proposed model is used to analyze the differences in person allocation between different types of households. The results indicate that life-cycle and household role, income, gender, employment status, and several types of constraints (activities including cost, time-availability, vehicle-availability, coordination constraints, and child-care obligations) affect person allocation decisions in the context of maintenance activities. The empirical results indicate the presence of various sources of correlations across persons, over activities, and within-household that are significant. In addition, the data also provides evidence that the unobserved variances in person selection utilities are not constant across households. A better understanding of these within-household interactions and between-household differences may be used in activity-based simulation models and to develop more effective and focused demand management measures.