This paper proposes a new method for measurement of the roll error motion of a slide table in a precision linear slide. The proposed method utilizes a pair of clinometers in the production process of a precision linea...This paper proposes a new method for measurement of the roll error motion of a slide table in a precision linear slide. The proposed method utilizes a pair of clinometers in the production process of a precision linear slide, where the roll error motion measurement will be carried out repeatedly to confirm whether the surface form errors of slide guideways in the linear slide are su ciently corrected by hand scraping process. In the proposed method, one of the clinometers is mounted on the slide table, while the other is placed on a vibration isolation table, on which the precision linear slide is mounted, so that influences of external disturbances can be cancelled. An experimental setup is built on a vibration isolation table, and some experiments are carried out to verify the feasibility of the proposed method.展开更多
Primary challenges with a forest inventory program are surveyors with various levels of experience and the turnover of inexperienced surveyors.Few studies have looked at the consistency of an instrument’s results amo...Primary challenges with a forest inventory program are surveyors with various levels of experience and the turnover of inexperienced surveyors.Few studies have looked at the consistency of an instrument’s results among inexperienced surveyors.Most studies have assessed whether instruments were significantly different.These tests do not indicate whether instruments were statistically equivalent,i.e.,that choosing either one would be acceptable under a certain level of tolerance.This study evaluated the consistency and statistical equivalence among instruments for measuring diameter at breast height(DBH)and for total tree height(HT)among inexperienced surveyors.The study was conducted as a randomized experiment with students from an introductory tree measurement course,using four types of DBH and HT instruments,and with different tree attributes.For DBH,the results show that D-tape was the most consistent across tree attributes and teams of inexperienced surveyors and was only statistically interchangeable with Caliper with a tolerance≥3 cm.For HT,Ultrasound was the most consistent but only statistically interchangeable with Laser with a tolerance≥8 m.A single type of instrument for measuring DBH and for HT is recommended,especially when field crews may be a mixture of experienced and inexperienced surveyors.Our study provides initial recommendations on the choice of instruments when either purchasing new ones or replacing old ones in forest inventories.展开更多
基金supported by Japan Society for the Promotion and Science (JSPS)
文摘This paper proposes a new method for measurement of the roll error motion of a slide table in a precision linear slide. The proposed method utilizes a pair of clinometers in the production process of a precision linear slide, where the roll error motion measurement will be carried out repeatedly to confirm whether the surface form errors of slide guideways in the linear slide are su ciently corrected by hand scraping process. In the proposed method, one of the clinometers is mounted on the slide table, while the other is placed on a vibration isolation table, on which the precision linear slide is mounted, so that influences of external disturbances can be cancelled. An experimental setup is built on a vibration isolation table, and some experiments are carried out to verify the feasibility of the proposed method.
文摘Primary challenges with a forest inventory program are surveyors with various levels of experience and the turnover of inexperienced surveyors.Few studies have looked at the consistency of an instrument’s results among inexperienced surveyors.Most studies have assessed whether instruments were significantly different.These tests do not indicate whether instruments were statistically equivalent,i.e.,that choosing either one would be acceptable under a certain level of tolerance.This study evaluated the consistency and statistical equivalence among instruments for measuring diameter at breast height(DBH)and for total tree height(HT)among inexperienced surveyors.The study was conducted as a randomized experiment with students from an introductory tree measurement course,using four types of DBH and HT instruments,and with different tree attributes.For DBH,the results show that D-tape was the most consistent across tree attributes and teams of inexperienced surveyors and was only statistically interchangeable with Caliper with a tolerance≥3 cm.For HT,Ultrasound was the most consistent but only statistically interchangeable with Laser with a tolerance≥8 m.A single type of instrument for measuring DBH and for HT is recommended,especially when field crews may be a mixture of experienced and inexperienced surveyors.Our study provides initial recommendations on the choice of instruments when either purchasing new ones or replacing old ones in forest inventories.
