Sliding mode control for altitude and attitude stabilization of quadrotor UAV with external disturbance

This paper addresses the problem of robust altitude and attitude control of ‘×’ mode configuration quadrotor UAV using Lyapunov stability based sliding mode control with saturation function. The dynamic model of the quadrotor was derived by considering nonlinearity factor. MATLAB Simulink was used to simulate the model in two different conditions; without and with the presence of external disturbance. This was done to test the robustness of the control method. Simulation results showed that the sliding mode controller provides good performance and robustness against disturbance

Sensor Fusion Algorithm by Complementary Filter for Attitude Estimation of Quadrotor with Low-Cost IMU

This paper proposes a sensor fusion algorithm by complementary filter technique for attitude estimation of quadrotor UAV using low-cost MEMS IMU. Angular rate from gyroscope tend to drift over a time while accelerometer data is commonly effected with environmental noise. Therefore, high frequency gyroscope signal and low frequency accelerometer signal is fused using complementary filter algorithm. The complementary filter scaling factor K1=0.98 and K2=0.02 are used to merge both gyro and accelerometer. The results show that the smooth roll, pitch and yaw attitude angle can be obtained from the low cost IMU by using proposed sensor fusion algorithm

Adaptive spatial mode of space-time and spacefrequency OFDM system over fading channels

In this paper we present a 2 transmit 1 receive (1 Tx : 1 Rx) adaptive spatial mode (ASM) of space-time (ST) and space-frequency (SF) orthogonal frequency division multiplexing (OFDM). At low signal to noise ratio (SNR) we employ ST-OFDM and switch to SF-OFDM at a certain SNR threshold. We determine this threshold from the intersection of individual performance curves. Results show a gain of 9 dB (at a bit error rate of 10-3) is achieved by employing adaptive spatial mode compared to a fixed ST-OFDM, almost 6 dB to fixed SF-OFDM, 4 dB to Coded ST-OFDM and 2 dB to a fixed coded SF-OFDM, at a delay spread of 700 ns

Sonographic Appearance of Abdominal Wall at the Left Flank of Laparotomy Incision Site in Ettawah Grade Does

The aim of this study was to describe the sonographic appearance of abdominal wall at the left flank of laparotomy incision site in 11 mated Ettawah grade does. Brightness-mode ultrasound examination by using transducer with frequency of 5.0-6.0 MHz was conducted to grouping the does based on their pregnancy statuses. The incision site of the abdominal wall at left flank laparotomy was transcutaneous-scanned as long as 8 cm vertically. The sonographic appearance of the laparotomy wall thickness showed that in all groups of does were similar and not different statistically. The thickness of oblique external and oblique internal abdominal muscles increased in the pregnant does as compared to non-pregnant does (P<0.05)

PI Controller Design Using Model Reference Adaptive Control Approaches For A Chemical Process

This paper discusses the application of Model Reference Adaptive Control (MRAC) concepts in designing an adaptive feedback controller to tune a given PI controller. The approaches of using the gradient (MIT) and stability (Lyapunov) methods are shown. The effectiveness of the two methods are shown through simulation and comparison is made to show which method give the best result. The results show that the stability method produces a better result

Temperature influence on total volatile compounds (TVOCs) inside the car cabin of visible light transmittance

In the automotive industry indoor air quality or Vehicle Indoor Air Quality (VIAQ) are caused by various substances emitted from interior materials inside a vehicle. The volatile organic compounds (VOCs) are an example of emitted substances from the interior materials which is harmful to the human body. As stated by previous researches, there is a strong correlation between the total VOCs emission and interior temperature. This occurs due to the solar radiation through the back window glasses, windscreen and side window glasses. This trapped heat can accelerate the melting process of trim materials such as hard plastic and rubber, thus causing the emission of total VOCs (TVOCs). Therefore, reducing the percentage of visible light transmittance (VLT) will help to reduce radiation process. The aim of this study is to investigate the effect of VLT level on TVOCs emission in the vehicle cabin under static condition (parked and unventilated) and operating condition (driving and air-conditioned). For static condition the result shows that the TVOCs concentration linearly decreases whenever the percentage of VLT level decreases. However, for operating condition the percentage of VLT have less significance after 50 minutes driving time. In conclusion, the VLT levels have a strong relationship to the TVOCs concentration despite after a long driving time

The effects of Momordica charantia on the liver in streptozotocin-induced diabetes in neonatal rats

The aim of this study is to determine the effects of Momordica charantia (MC) fruit aqueous extract on the liver histopathological changes in neonatal rats streptozotocin (STZ)-induced diabetes mellitus type II. Diabetes mellitus was induced in one day old neonatal Sprague-Dawley rats with STZ (85 mg/kg) and monitored for 12 weeks thereafter. The diabetic rats were separated into three groups as follows: the diabetic control group (nSTZ), the MC treated diabetic group (nSTZ/M), and the glibenclamide treated diabetic group (nSTZ/G). At the end of the treatment, blood glucose, serum insulin, alanine amino transferases (ALT) and aspartate amino transferases (AST) level was measured. Malondialdehyde (MDA) concentration was measured in the plasma and liver. The liver samples were processed for light microscopy examination. The results showed a reduction of blood glucose, ALT and AST, and increment of insulin level in the nSTZ/M and nSTZ/G rats. Administration of MC reduced the MDA concentration in plasma and liver of the nSTZ/M rats. Glucose tolerance and insulin sensitivity was improved in the nSTZ/M and nSTZ/G groups. The degenerative changes in liver were alleviated in the nSTZ/M and nSTZ/G groups. These results suggested that MC fruit aqueous extract may have a significant role in alleviating liver damage in the nSTZ-diabetic rats.Key words: Diabetes, Momordica charantia, liver, neonatal rat

A Pilot Study on the Sustainability of the Engineers' Technical Knowledge Repository (KR) Establishment: a Malaysian Case

. Knowledge is an important resource in this current economic condition where organizations are competing in creating more innovation in order to maintain their business in the marketplace. Thus, it is important for an establishment to continue their capitalizing their knowledge asset as knowledge is vital to gain competitive advantage in this current epoch. With regards to that, an organization needs to plan and design the most appropriate approach which enable the organizational knowledge asset to be captured, stored and utilized its valuable benefits. Establishing a knowledge repository (KR) is one of the approaches organizations adapt in maintaining organizational knowledge asset and promoting knowledge reuse. The focal point of this research is on the sustainability of knowledge repository establishment in sharing, transferring, storing the technical knowledge of the key personnel from the Malaysian public sector. The study adopted the qualitative research approach as its aim is to look into the sustainability of KR in an in-depth manner which concerned with the societal facet of that particular system. Therefore, the paper discusses the outcomes from the pilot study on which elements that sustain the significant impact in contributing to the process of knowledge repository sustainability in an organization

Determination of antioxidant activity in methanolic and chloroformic extracts of Momordica charantia

The aim of this study was to determine and compare the antioxidant activity of methanolic and chloroformic extracts of Momordica charantia (MC) fruit. In this study, the total antioxidant and free radical scavenging activities in methanolic and chloroformic were measured by ferric thiocyanate (FTC), thiobarbituric acid (TBA) and 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) methods. Total phenol and flavonoid contents of the MC extracts were also evaluated. The total antioxidant activity results indicated that, the inhibition percent of methanolic extract was significantly higher than the inhibition percent of chloroformic extract in the FTC and TBA methods. A higher IC50 value for free radical scavenging was found for methanolic extract when compared with chloroformic extract. Methanolic extract contained a significantly higher concentration of total phenols and flavonoids when compared with chloroformic extract. Methanolic extract contained more potent antioxidant and high polyphenol compounds when compared with chloroformic extract. The present study, confirmed that, the type of solvent has an important role in detecting plant compounds. The natural plant antioxidants and phenolics compounds in MC have the capability of being used in food systems to preserve food quality.Key words: Momordica charantia, antioxidant activity, polyphenol compounds, phenolics, flavonoids

Tax Literacy Rate Among Taxpayers: Evidence From Malaysia

The extent of taxpayer knowledge can have a major impact on the degree of compliance with taxation rules and regulation. Low knowledge creates uncertainty about requirements of the tax regulation and can lead to high degree of involun-tary non-compliance. This study high¬lighted the importance of taxation knowledge by measuring Malaysian’s tax payers’ tax literacy rate taking into consideration the following criteria: 1) Individual ability to fill the tax return form inde¬pendently, 2) Taxpayer’s interest in learning about tax, and 3) Incident of errors in filling the tax re¬turn forms. Questionnaires were used in this study to ascertain the tax liter-acy rate. The results in¬dicate that among the respondents, professionals group has the highest percentage of tax literacy and the formers have the lowest percentage. Majority of the businessmen paid for services for fill¬ing tax return forms and high rank officers are the highest among the group for not employing oth¬ers for filling the tax forms. Businessmen have the highest incidence of error in filling tax return form and most of teachers reported no error in filling such forms. Most business-men showed interests and were willing to spend time to learn about taxation. They perceived taxation knowledge as an important tool for themselves and also for their family. Overall results indicate that more than 60% of respondents are tax lit-erate. However, a significant number of them are actually‘ functionally tax illiter-ate’. Most of them thought that they knew a lot about taxation as they had read them in the tax literature sent to them by the IRB. However, the evidence was con-trary to this conjecture. The in¬formation on the extent of taxpayers’ knowledge is potentially useful to the tax authorities to assist them in developing effective com-pliance enhancement policie