Comparing Onsite and Offsite Methods for Measuring Norms for Trail Impacts

This study examined the comparability of onsite and offsite methods for measuring norms for trail impacts using photo/survey techniques. A total of 449 subjects participated in a study of Mudeung-Mountain Provincial Park, Gwang-Ju, Korea. For the overall photo evaluation method (OPEM), respondents rated the acceptability of bare soil area for each of a series of photographs. For the specific photo evaluation method (SPEM), respondents selected a photograph that illustrated the largest acceptable proportion of bare soil area from a series of 10 photographs. Overall, there were no substantial differences in maximum acceptable impacts between onsite (onsite-I visitor group surveyed at the actual trail points and onsite-II departing visitor group surveyed at the exit area) and offsite (students surveyed in a laboratory setting) groups for the two norm measurement alternatives (OPEM and SPEM). Subjects’ difficulty ratings were low for both methods, and there were no substantial differences in norms between individuals with high and low levels of experience at the park. The offsite method appears to be substitutable for onsite methods in this particular study area, which is a frontcountry setting with a relatively simple range of recreation opportunities. Implications and further studies are discussed.     

在线自动监测与手工分析地表水总氮的可比性研究

对比浙江省地表水水质自动监测站总氮在线监测与实验室手工方法,分析进口水质总氮自动监测仪在国内的适用性以及与手工方法的可比性。结果表明,一些国外引进的自动监测仪在国内使用时要根据我国水体的实际情况在实验条件上作一定的改进,改进后的监测数据与手工方法才具有可比性。     

材料性能试验总延伸率的可比性

金属材料的总延伸率δ是很重要的性能参数.但在单向拉伸试验中,由于试样原始标距不同,所获得的总延我早率也不同.此文讨论了不同原始标距时,总延伸率δ的可比性问题,推导出了理论换算公式,并以实验结果加以验证.