多项式拟合法在船载外测数据实时压缩算法中的应用

为了解决船载外测设备采样数量大的问题,船中心机必须对外测数据进行实时预处 理,适当压缩后才能向外发送。将多项式拟合的方法应用到外测数据的实时压缩算法之 中,通过建立一组正交多项式基,运用最小二乘法估计得到拟合点的平滑公式,在综合分析 多项式截断误差和随机误差的基础上总结得出最佳压缩多项式次数和采样点数。理论分析和 实例仿真结果均表明,该方法达到了良好的压缩和滤噪的效果,能够在比较高的精度范围内 体现数据的真实曲线特征。     

Recreation Specialization Among ATV Users and Its Relationship to Environmental Attitudes and Management Preferences on the Island of Newfoundland

The purpose of this study was to identify and document the attitudes, perceptions, and resource management preferences of all-terrain vehicle (ATV) users through the recreation specialization framework. Data were collected on the Burin Peninsula on the south coast of the island portion of the province of Newfoundland and Labrador. Variables were operationalized using a quantitative survey which generated an 8-item specialization index based on behavioral, cognitive, and affective measures of involvement in ATV riding. Three distinct subgroups of ATV users were identified through K-means cluster analysis. One-way ANOVA tests revealed significant differences across specialization groups. Results document the spectrum of attitudes and management preferences and provide recommendations for outdoor recreation policies that reflect the needs of a wide variety of ATV users.     

Weather Studies in Outdoor Recreation and Nature-Based Tourism: A Research Synthesis and Gap Analysis

ABSTRACT

The impact of weather on outdoor recreation and nature-based tourism has received increasing attention from the research community during the past ten years. This article synthesizes the results of those inquiries, categorizing their predominant themes and identifying knowledge gaps. One hundred eighty-four weather-related articles drawn from a cross-section of international journals served as the foundation for this work. The research synthesis identified three recurring themes: weather-related variables that influence outdoor recreation and nature-based tourism, the importance of geographic research context, and prevailing activity types. A gap analysis indicated an abundance of underinvestigated topics in weather-related studies in outdoor recreation and nature-based tourism. The article concludes with recommendations for future weather-related studies in outdoor recreation and nature-based tourism developed from the predominant themes uncovered in the research synthesis and research needs discovered in the gap analysis.     

Recreation Specialization Among New Zealand River Recreation Users: A Multiactivity Study of Motivation and Site Preference

This study explored the influence of specialization and activity on motivation to participate and site preference among three activities: whitewater kayaking, multisport racing, and fishing. Subjects consisted of 270 river-based recreationists in New Zealand. MANOVA results indicate a moderate effect for activity on motives to participate and site preference and a weak effect for specialization. Inter-activity motivation and site preference differences reveal similarity between whitewater kayaking and multisport and distinct differences between these and fishing. In these data, the distinctive nature of the activity provides greater explanatory power for motivation to participate and site preference than does the specialization construct.     

Models of Site‐choice for Walks in Rural Ireland: Exploring Cost Heterogeneity

Farmland can confer significant public good benefits to society aside from its role in agricultural production. In this article, we investigate preferences of rural residents for the use of farmland as a recreational resource. In particular, we use a choice experiment to determine preferences for the development of farmland walking trails. Our modelling approach uses a series of mixed logit models to assess the impact of alternative distributional assumptions for the cost coefficient on the welfare estimates associated with the provision of the trails. Our results reveal that using a mixture of discrete and continuous distributions to represent cost heterogeneity leads to a better model fit and lower welfare estimates. Our results further reveal that Irish rural residents show positive preferences for the development of farmland walking trails in the Irish countryside.     

大连湾-老铁山水道小型运输船船型经济性论证分析

根据大连湾-老铁山水道的情况,考虑变吃水的运输方式,以船长、船宽、吃水及航速作为变量来进行船型方案的组合。选用净现值、内部收益率、投资回收期、必要运费率和综合经济指标作为衡量船型方案的标准,通过分析计算得出最佳的船型方案。     

船载外测设备测速数据的误差修正

针对“远望”号航天远洋测量船对航天飞行器动态测量的特点，分析了影响船载外测设备测速数据的各种因素，提出了对测速数据进行误差修正的设想和思路并给出了误差修正公式；同时用实战任务中的实测数据进行计算，考察了此方法误差修正的效果。计算结果表明，使用经各种误差修正后的测速数据参与初轨计算能有效提高定轨精度。     

中小城市家庭规模与游憩行为的关系研究

家庭对居民游憩行为的影响已有研究,但家庭规模对居民游憩影响的研究国内并不多见.本次研究在全国选取5个中小城市,共回收问卷1818份,对游憩需求、游憩场所、游憩活动、游憩障碍进行调查.通过因子分析和单因素方差检验分析家庭规模对游憩行为的影响,提出家庭群体的游憩行为特征,并结合家庭生命周期理论对其游憩行为特征进行解释.     

提高绞吸式挖泥船产量之我见

文中从提高挖泥运转时间、提高流速、提高泥浆浓度三个方面论述了提高绞吸式挖泥船产量的方法。     

浙江省水路规费稽征管理系统设计浅谈

文章结合嘉兴市港航管理局征收管理的实际,对船舶管理、票据管理、网络建设与银行间的缴费进行了深入的探讨,并作了详细的介绍,通过嘉兴市港航管理局的实际应用,取得了较为显著的经济效益如社会效益。