Universiti Teknikal Malaysia Melaka: UTeM Open Journal System
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An FPGA-based Design Approach for Microsatellites Telemetry Subsystem
Get PDFThe Tele-command and Telemetry (TT&C) subsystems are one of the vital components in satellites. Commanding, managing and data sampling from different sections of the satellite are performed through the TT&C subsystem. The telemetry and Tele-command parts of this subsystem could be implemented cooperatively with or separately from each other. Based on the satellite requirements, its mission and orbital lifetime and cost various approaches may be used in order to implement this subsystem. Furthermore, nowadays, the development of satellite subsystems based on commercial devices because of their low cost and accessibility is more attractive. However, their endurance for harsh space environment remains as a severe challenge. The Field Programmable Gate Arrays (FPGAs), one of the best-developed commercial devices, are most successfully option in this application field. Nevertheless, the system designing methodology and the reliability of the implemented system on FPGAs remain as two major concerns. In this paper designing method and implementation result of Telemetry subsystem on field programmable gate array (FPGA) is presented. The implemented subsystem successfully passed environmental test according to ECSS standard. Furthermore, flight data confirm the feasibility of the presented FPGA based design methodology
Microaneurysms Segmentation in Retinal Images for Early Detection of Diabetic Retinopathy
Get PDFMicroaneurysms (MAs) are the tiny aneurysms which show the earliest sign of diabetic retinopathy (DR). MAs might progress and harm human eyes if not treated. This paper presents an automatic method for segmentation of MAs in order to control the progression of DR. MESSIDOR database of 40 random images were utilised for further processing. The proposed approach covered pre-processing steps, contrast enhancement, filtration and segmentation by h-maxima transform and multilevel thresholding. Some post-processing techniques also involved in this approach using morphological operation. The detected MAs determined the grade of disease severity. The result showed that the percentage of severity disease detected was 60%
MULTI-RESPONSE OPTIMIZATION OF PLASTIC INJECTION MOULDING PROCESS USING GREY RELATIONAL ANALYSIS BASED IN TAGUCHI METHOD
Get PDFThis project investigates the multi-response optimization using grey relational analysis based in Taguchi method of plastic injection mould. Four input process parameters selected are mould temperature, melting temperature, injection time and cooling time. The responses investigated were part weight, shrinkage, warpage, ultimate tensile strength, tensile modulus and percentage of elongation. It is found that the optimum setting parameter generated from multi-response optimization is at run number 4 that are mould temperature at 56oC, melting temperature at 250oC, injection time at 0.7s and cooling time at 15.4s. Result of run number 4 for multi-response optimization for part weight, warpage, shrinkage, tensile ultimate strength, tensile modulus and percentage of elongation are 6.9807g, 0.087mm, 1.73%, 24.732MPa, 981.76MPa and 31.37%, respectively. Multi-response optimization results show that all response results are not higher or lower than experimental results. This is because multi-response optimization normalized all response value. Thus, by implemented multi-response optimization process, the materials characteristics value of plastic part can be predicted
Query Rewriting using Multitier Materialized Views for Cyber Manufacturing Reporting
Get PDFWithin cyber manufacturing context, Internet of Data (IoD) technology has enabled manufacturing sector to store and transfer mass data rapidly for processing. Data growth which is driven by advancement in the way data are produced and interconnected has caused volume of data a crucial issue to address. As such, in monitoring delicate wafer processing in semiconductor manufacturing, reporting delay problem caused by databases of high data volumes is intolerable. This is because, various reports (that require access to large databases) need to be frequently generated in the shortest time possible. Reporting delay is usually handled through SQL query rewriting. In this paper, the results of experimenting SQL query rewriting by utilizing multitier materialized views structure is presented. In particular, we define sub-materialized views (SMVs) concept, and implement it using real data sets from SilTerra (a semiconductor industry). The outcome of the experiment supports the hypothesis that SQL query rewriting using SMV outperforms the classic rewriting. The results reveal that the performance of SMV is far better (than without SMV) for complex queries against large data sets. The benefits of SMV are not limited to cyber manufacturing domain as the use of SMV can contribute other industries with similar problem
MULTIPLE ANDROID PACKAGE FILES EXTRACTOR IN MINING REQUEST PERMISSIONS AND API CALLS
Get PDFAndroid smartphone has the highest demand in the world due to the ability of the devices and the open source software concept. Numbers of Android applications are increasing as to fulfill users and businesses’ needs. Not only Android gains huge business return but its applications has also become the target of attackers. One of the approaches to investigate and detect malware is through a reverse engineering technique where the profile parameters are extracted. The process of reversing Android execute file (.apk) individually takes a long time. Other than having used several tools, the approach leaves open the possibility of misconduct during the mining of necessary source codes. Therefore, an Android permissions and Application Programming Interface (API) calls extractor tool were developed for Android mobile devices apps. This tool had the capability to record all request permissions and required API calls inside the AndroidManifest.xml and classes.dex made to App executable file. In addition, the automatic feature of the tool allowed for the recording of the permission and API calls more than one Android Package Kit (APK) files at a time. MAPE (Multiple Android Package Extractor) was developed using Node.js. Currently, researchers either disclose mining techniques or use existing tools manually. MAPE used a sequential search in Depth First Search (DFS) technique to accomplish the operation. This tool can shorten the researchers’ processing time on retrieving request permissions and targeting API calls. The output produced by MAPE can be used for several purposes such as Apps categorization and malware detection
Influence of Curing Temperature on Mechanical Properties of Woven Jute Reinforced Polyester Composite
Get PDFThe aim of this work is to evaluate the influence of curing temperature onto the mechanical properties of woven jute/polyester composite using warm compression moulding. 40 vol.% woven jute fibres were compressed moulded at a pressure of 2.0 MPa, holding time of 900s by varying the fabrication temperature in three levels which are 150°C, 170°C and 180 °C. The mechanical and thermal properties were characterized using flexural and impact testing, DSC and TGA. Optimum mechanical properties are achieved at moulding temperature of 170°C. The flexural strength and flexural modulus at the optimised moulding temperature are 37.20 MPa and 0.84 GPa respectively, while their impact strength is 19.38 kJm-2. Morphological examination revealed that the composite failed in brittle manner and due to fibre pull-out indicating of weak interface
SUPPRESSION OF CUTTING FORCES USING COMBINED INVERSE MODEL BASED DISTURBANCE OBSERVER AND DISTURBANCE FORCE OBSERVER
Get PDFThis paper focuses on damping strategies that addressed the effect that high frequency harmonics content of cutting force have on positioning accuracy of the x-axis of an XY positioning table via controller and observer design approaches. Cutting force generated from direct contact between the workpiece and cutting tool becomes input disturbance to the drive system of the positioning table. The force high frequency components if left undamped would generate vibration to the system thus affecting the system positioning accuracy, surface finish quality as well as tool life. For this purpose, a cascade P/PI position controller, an Inverse Model Based Disturbance Observer (IMBDO) and a Disturbance Force Observer (DFO) were designed and numerically analysed. The cascade P/PI controller was designed using traditional loop shaping frequency domain method. IMBDO estimates the input disturbance and any unmodelled system dynamics while DFO performs direct estimation of the cutting force using knowledge of harmonic frequencies corresponding to the input cutting force. A combined cascade P/PI controller with IMBDO and DFO reduced additional 3.83% and 1.90% tracking errors compared to separate application of IMBDO and DFO. This novel control approach produced between 34-80% greater reductions in peak amplitudes of the harmonics content of the cutting forces compared to cascade P/PI
Optimization of Drill Geometry Design to Minimize Thermal Necrosis in Surgical Bone Drilling
Get PDFDuring the orthopedic bone drilling surgery procedures, the friction between the drill and bones surface leads to a localized temperature increase results in thermal necrosis on the soft tissue surrounding the hole. The magnitudes of the friction energy are greatly dependent with the drill geometry design. Recognizing the importance on studying this phenomenon, this paper aim to investigate the effects of drill geometry on temperatures during the bone drilling procedure. Totals of 17 drills were design and tested with different geometry namely point angle, helix angle and web thickness on different penetration angle (0⁰, 15⁰, and 30⁰) to mimic the manually control penetration by the surgeon. From the conducted investigation, the most significant parameter that affects the temperature rise was the penetration angle followed by the point angle. In addition, the interaction between helix angle and web thickness also controlled the drilling temperature. From the result, the optimum drill-bit design geometry was 21.8% web thickness, 126.92° point angle and 36.53° helix angle which produces the minimum drilling temperature
Automated Printed Circuit Board Assembly Verification and Validation System
Get PDFWith the fast-paced evolution in the engineering field especially in electronics, the design of circuitry is becoming more and more complex. Hence, to make sure the Printed Circuit Board Assembly (PCBA) is designed correctly, the prototypes of the PCBA have to be tested and validated before moving on to manufacturing and production process. The InCircuit Test (ICT) and flying probes are too expensive to be applied for a prototype stage. Hence, the verification and validation (V&V) test for the prototype of PCBA is done manually by the V&V engineers. However, it is a complex and time-consuming process. Therefore, there is a requirement to improve the current PCBA prototype verification and validation. This project is proposed to assist V&V engineers to perform a V&V test for PCBA prototype. This project basically consists of a CNC machine, which has total five degrees of freedom with measuring probe at the end effector. Three stepper motors were used to move the x, y and z coordinate of the probe. The stepper motors were controlled by controller myRIO with stepper motor driver A4988. Besides that, another two smaller stepper motors were used for the probing mechanism. The probing mechanism was designed and simulated by using SolidWorks software. For software, the data extraction from the PCB file was done by the algorithm built using LabVIEW. In addition, a graphical user interface (GUI) was also designed and built using LabVIEW. The system was tested in terms of accuracy and consistency by using samples of PCB. The results from the evaluation showed about 70.83% of accuracy in average. Overall, the performance of the system is acceptable and the accuracy of the system can be improved by the implementation of closed-loop control into the system
TIO2 Nanoparticles Reinforced Lead-Free 96.5Sn–3.0Ag–0.5Cu Solder Paste for Ultra-Fine Package Assembly in Reflow Soldering Process
No full textUltra-fine package assembly using TiO2 nanoparticle reinforced lead-free solder paste was carried out in the reflow soldering process. TiO2 nanoparticles were mixed with the SAC solder paste at 0.01, 0.05 and 0.15 wt.%. The ultra-fine package (passive capacitor) was mounted on PCB with a thickness of 2.0 mm using the nanocomposite solders. Voids, microstructure and TiO2 nanoparticle distributions were inspected through the X-ray, SEM and HRTEM. The ultra-fine solder joints were formed perfectly without any void formation. The TiO2 nanoparticles are distributed homogenously in the solder joint. The mechanism of IMC reaction during the reflow soldering process is also discussed. Homogeneous mixing of nanoparticle plays a significant role for the distribution of the nanoparticle in the solder joint