• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.11
• /
• pp.2945-2965
• /
• 2023

The laser inertial measurement unit is a precision device widely used in rocket navigation system and other equipment, and its quality is directly related to navigation accuracy. In the quality evaluation of laser inertial measurement unit, there is inevitably uncertainty in the index input information. First, the input numerical information is in interval form. Second, the index input grade and the quality evaluation result grade are given according to different national standards. So, it is a key step to transform the interval information input by the index into the data form consistent with the evaluation result grade. In the case of uncertain input, this paper puts forward a method based on probability distribution to solve the problem of asymmetry between the reference grade given by the index and the evaluation result grade when evaluating the quality of laser inertial measurement unit. By mapping the numerical relationship between the designated reference level and the evaluation reference level of the index information under different distributions, the index evidence symmetrical with the evaluation reference level is given. After the uncertain input information is transformed into evidence of interval degree distribution by this method, the information fusion of interval degree distribution evidence is carried out by interval evidential reasoning algorithm, and the evaluation result is obtained by projection covariance matrix adaptive evolution strategy optimization. Taking a five-meter redundant laser inertial measurement unit as an example, the applicability and effectiveness of this method are verified.

• Journal of Practical Engineering Education
• /
• v.10 no.2
• /
• pp.119-124
• /
• 2018

Educational equipment that enables the user or device to recognize the indoor position by using the acceleration and angular velocity of the IMU (Inertial Measurement Unit) sensor is introduced. With this educational equipment, various position recognition and tracking algorithms can be learned and creative engineering design works can be realized. The data value of the IMU sensor is transmitted to the MCU (microcontroller unit) through $I^2C$ (Inter-Integrated Circuit), and the indoor position recognition algorithm is applied by processing the data value through the filter and numerical method. It is then designed to use wireless communication to send and receive processed values and to be recognized by the user. As an example using this equipament, the case of "Implementation and recognition of virtual position using computation of moving direction and distance using IMU sensor" is introduced, and various creative engineering design application is discussed.

• International Journal of Reliability and Applications
• /
• v.9 no.1
• /
• pp.17-30
• /
• 2008

Analysis of measurement systems is important to determine if the measurement process is adequate to measure the part-to-part variability in the process. Control chart techniques provide an effective, and easy-to-use method for performing this analysis. However, application with the real data for the evaluation procedure for multiple measurement systems have not been demonstrated. This research will provide a methodology for the evaluation of part-to-part variation and variation of different measurement systems step by step followed by number of case studies for each methodologies provided.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.606-609
• /
• 2006

In this study, it was selected that in order to make an investigation into the status of the unit water content control of the ready-mixed concrete plants in the country, Capacitance Measurement Method out of various methods which are able to gauge the amount of unit water content in fresh concrete. Then, it were estimated that the quantity of unit water in fresh concrete and the technical standard of every mixture design of the six ready-mixed concrete plants chosen at random in the country. Finally, based on this study, it was proposed as fundamental data to utilize measurement techniques of the quantity of unit water for the quality control of the ready-mixed concrete in construction field.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.96.5-96
• /
• 2001

The probe with a 110mm diameter is originated and fabricated to measure hole accuracies of extremely deepholes. It consists of a measuring unit, an actuator unit, an active rotation stopper and a feed unit. The rolling of the probe is restricted and adjusted by the active rotation stopper. The probe is fed by the feed unit. In this measurement, accuracies are measured by using a rolling proof apparatus and machine table of deep hole boring machine instead of the stopper and the feed unit, respectively. Straightness, roundness and a diameter of a 110-mm hole are measured by the probe and testers made for each measuring purpose ...

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.745-748
• /
• 2008

On investigation about quick measurement technology of unit water at range of W/B=35% in high strength, the average error of the Di-electric constant moisture tester A has measured more than $23.0kg/m^3$ unit water content of design and the average error of the method of unit volume weigh was less than $-9.6kg/m^3$. The average error with mixing factor has influenced with a kind of sand, but had not influenced with unit water content of design. Therefore, it will be for introduce business decide require more than a study about cement, sand, superplasticizer, etc.

• The Journal of Korean Physical Therapy
• /
• v.29 no.3
• /
• pp.145-151
• /
• 2017

Purpose: The purpose of this study was to investigate the validity and reliability of the measurement of shoulder joint motions using an inertial measurement unit (IMU). Methods: For this study, 33 participants (32 females and 1 male) were recruited. The subjects were passively positioned with the shoulder placed at specific angles using a goniometer (shoulder flexion $0^{\circ}-170^{\circ}$, abduction $0^{\circ}-170^{\circ}$, external rotation $0^{\circ}-90^{\circ}$, and internal rotation $0^{\circ}-60^{\circ}$ angles). Kinematic data on the shoulder joints were simultaneously obtained using IMU three-dimensional (3D) angular measurement (MyoMotion) and photographic measurement. Test-retest reliability and concurrent validity were examined. Results: The MyoMotion system provided good to very good relative reliability with small standard error of measurement (SEM) and minimal detectable change (MDC) values from all three planes. It also presented acceptable validity, except for some of shoulder flexion, shoulder external rotation, and shoulder abduction. There was a trend for the shoulder joint measurements to be underestimated using the IMU 3D angular measurement system compared to the goniometer and photo methods in all planes. Conclusion: The IMU 3D angular measurement provided a reliable measurement and presented acceptable validity. However, it showed relatively low accuracy in some shoulder positions. Therefore, using the MyoMotion measurement system to assess shoulder joint angles would be recommended only with careful consideration and supervision in all situations.

• Journal of Environmental Science International
• /
• v.24 no.4
• /
• pp.393-401
• /
• 2015

Rainfall-runoff model of Jeju Oedo Stream was used to compute the optimal unit hydrograph by HEC-HMS model that reflecting on watershed characteristics. Each rainfall event was comparatively analyzed with the actual flow measurement using Clark, Snyder and SCS synthetic methods for derived unit hydrograph. Subsequently, the null hypothesis was established as p-value for peak flow and peak time of each unit hydrograph by one-way ANOVA(Analysis of variance) was larger than significance level of 0.05. There was no significant difference in peak flow and peak time between different methods of unit hydrograph. As a result of comparing error rate with actual flow measurement data, Clark synthetic unit graph best reflected in Oedo Stream as compared to other methods, and error rate of Clark unit hydrograph was 0.02~1.93% and error rate at peak time was 0~2.74%.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.21 no.48
• /
• pp.201-211
• /
• 1998

The fundamental object of work measurement is to precisely establish the time standards, which are the indices of labor productivity. This study discussed the development of robot work measurement method that could establish the time standard effectively. In manufacturing industries the various robot tasks are generally classified and standardized by the unit motions. The Robot Modularization of the Unit Motion (ROMUM) was realized by the module of two steps GET and PUT unit motions. This method reduced time and effort of analysis, and could be done with ease. Therefore, ROMUM will increase the convenience of use for the unskilled worker and decrease the time required, cost and errors. And, it will contribute to reduce the unnecessary motion by robot motion analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.203-206
• /
• 2001

This paper presents a straightness measurement system for flat and long workpieces. The measurement system consists of a laser optical unit, a CCD camera and processing system, and a carrier system with a stylus. The carrier system accompanies the stylus, which displaces a retroreflector along the surface profile. The optical unit is used to optically amplify the displacement of retroreflector. The CCD camera and processing system finally identifies the vertical displacement of the stylus unit. The developed system is applied to two surfaces: ground surface and LM guide surface. The experimental results show that the developed system can measure the straightness of flat surfaces within sub-micron error.