BUKU ABSTRAK - Universiti Putra Malaysia

Science, Technology & Engineering
Design and Prototype of an Ergonomic Back-leaning Posture Support for
Motorbike Riders
Prof. Ir. Dr. Mohd. Sapuan Salit
Karmegam Kurupiah, Md. Yusof Ismail and Napsiah Ismail
Faculty of Engineering, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6336; sapuan@eng.upm.edu.my
This study presents a prototype of an ergonomic back-leaning posture support for motorbike in Malaysia.
Motorbike riders are more exposed to musculoskeletal disorders such as lower back pain. Prototype consists
of two basic components, frame and backrest cushion. Prototype back-leaning posture support is evaluated by
comparing it with anthropometry data in terms of flexible range accommodations and by test runs on road with
riders. Prototype has shown better comfort seating, adjustability, stability, solidity, durability and safety for riders.
Keywords: Back posture support, ergonomic, lower back pain, motorbike
Robust Estimators in Simple Mediation Analysis
Assoc. Prof. Dr. Habshah Midi
Anwar Fitrianto
Institute of Mathematical Research, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6876; habshahmidi@gmail.com
Simple mediation model involves a series of regression equations. The Ordinary Least Squares (OLS)
method is often used to estimate the parameters of the mediation model. However, many researchers are not
aware of the fact that the OLS estimators suffer a huge set back in the presence of outliers. In order to rectify this
problem, robust methods which are not easily affected by outliers, have been created. We have proposed a robust
M and MM procedure for estimation of mediation parameters in the presence of single outlier. The performance
of the MM, M, and OLS estimates are compared by numerical example. The empirical evidence shows that the
MM, M, and OLS estimators are equally good in a well behaved data. Nevertheless, when contamination occurs
in the data, the performance of the MM is the best followed by the M and the OLS estimators.
Keywords: Simulation, mediation analysis, unusual observation, outliers, indirect effect, M-estimator, MM-estimator
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