Mehran University Research Journal of Engineering and Technology

4

Authors: Mazhar Hussain Peerzada, Awais Khatri, Sadaf Aftab Abbasi

Much less has been done on failure characteristics of 3D (Three Dimensional) woven fabrics. This work is to attempt to this need. Shear behavior is key characteristic and play direct role to the performance of woven fabrics. In this study, three different 3D weave structures have been used to analyze the fabric shear rigidity. Shear analysis has been carried out in both directions using Kawabata evaluating system. Based on the results, a relationship of shear rigidity (G) and shear hysteresis are compared and analyzed in zero and 90o direction of fabric.

6

Authors: Sheeraz Memon, Faisal Karim Shaikh, Javed Ali Baloch

The environment affects largely the performance of automatic speaker recognition. This work investigates the effects of clinical environment on the task of speaker recognition. For this task we have used two sets of speakers, a clinical set which consists of speech samples from 70 clinically depressed speakers and a control set which comprises of 68 clinically non-depressed speakers. The MFCCs (Mel Frequency Cepstral Coefficients) are applied for feature extraction, and a number of modeling methods such as GMM-EM (Gaussian Mixture Models Based on Expectation Maximization), GMM based on Kmeans (GMM-Kmeans), GMM-LBG based on Linde Buzo Gray, and GMM -ITVQ based on Information Theoretic Vector Quantization are used. The different modeling methods are evaluated for the novel speech corpus. The results suggest that the speaker recognition rates for the depressed speakers are lower (60-71%) than for the non-depressed speakers (79-89%). This paper further investigate the performance of VQ (Vector Quantization) based Gaussian modeling, and proposes a novel approach called GMM-ITVQ. The results suggest that GMM-EM has the higher recognition rates however, the performance of GMMITVQ is comparable to GMM-EM.

6

Authors: Uzma Syed, Roger H. Wardman, Rafique Ahmed Jhatial

In this research software was designed for assessing the inter-yarn zone fabric porosity of Tencel plain weave fabrics in terms of flow of dye liquor by using Matlab. Fabric images were captured at constant light intensity and magnification using an optical microscope and image analysis software. The captured images were first converted into monochrome image and then into binary image at specific threshold value (150). The percentage of white pixels in the binary image were calculated which assessed the fabric porosity in percentage. The loosely woven fabric gives higher percentage of fabric porosity as compared to the tightly woven fabric. This software has potential to calculate the fabric porosity of plain weave fabric manufactured from any type of raw material.

8

Authors: Atif BinMansoor, Zohaib Khan, Shoab Ahmed Khan

Internet is a widely used medium for transfer of information due to its reach and ease of availability. However, internet is an insecure medium and any information might be easily intercepted and viewed during its transfer. Different mechanisms like cryptology and steganography are adopted to secure the data communication over an inherently insecure medium like internet. Cryptology scrambles the information in a manner that an unintended recipient cannot easily extract the information, while steganography hides the information in a cover object so that it is transferred unnoticed in the cover. Encrypted data may not be extracted easily but causes a direct suspicion to any observer, while data hidden using steganographic techniques go inconspicuous. Cryptanalysis is the process of attacking the encrypted text to extract the information, while steganalysis is the process of detecting the disguised messages. In literature, both cryptology and steganography are treated separately. In this paper, we present our research on an improved data security paradigm, where data is first encrypted using AES (Advanced Encryption Standard) and DES (Data Encryption Standard) cryptology algorithms. Both plain and encrypted data is hidden in the images using Model Based and F5 steganographic techniques. Features are extracted in DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform) domains using higher order statistics for steganalysis, and subsequently used to train a FLD (Fisher Linear Discriminant) classifier which is employed to categorize a separate set of images as clean or stego (containing hidden messages). Experimental results demonstrate improved data security using proposed CRYPTO-STEG approach compared to plain text steganography. Results also demonstrate that the Model Based steganography is more secure than the F5 steganography.

8

Authors: Zubair Ahmed Memon, Mohammad Aslam Uqaili, Mukhtiar Ali Unar

Power quality standards (IEEE-519) require to limit the total harmonic distortion within satisfactory range caused by power electronic based devices. Our work deals with the design of hybrid active filter to reduce current perturbations produced by power electronics based devices. The Instantaneous Active and Reactive Power Method (pq) is used to perform the identification of disturbing currents. The pq algorithm creates a reference current, whereas, this reference current is tracked by the current of the voltage source converter. The currents of the voltage source converter are controlled by hysteresis controller. Simulation results showed that the hybrid active filter can compensate the harmonic currents effectively and improve power quality.

10

Authors: Sania Bhatti , Manzoor AhmedHashmani , Naheed Shaikh

An Expert System is a computer program that simulates the human intelligence and behaviour in specific and limited domains. It is used to solve problems with tricks, shortcuts and heuristics i.e. rules of thumb. Checking a Plan (Map) to verify its compliance with building bylaws is a complex task mainly due to various rules and the exceptions to those rules. Humans are prone to make errors in such situations. Due to the problems faced by Building Control Department, HDA ( Hyderabad Development Authority) there is a strong need to develop a computerized system. In this research we have developed a prototype named as ESBBC (Expert System for Building Bylaws Compliance) for HDA that can help in their building plan checking system. The proposed solution is merging three frameworks, i.e. Java an OOP (Object Oriented Programming) language, Prolog- a rule based language and MS Access- for database. The solution is fulfilling the three main requirements of the HDA, i.e. Determination of whether a particular plan is in compliance with predefined building bylaws or not. (2) Offering search facility. (3) Maintaining records of plans which are entered for compliance checking. We have checked plans of 20 properties according to HDA building regulations using ESBBC and presented their results. The results show that ESBBC has capability to identify errors made by humans.

10

Authors: Imdadullah Siddiqui, Muhammad Hassan Agheem, Abdul Salam Soomro

The Meting-Jhimpir coalfield covers an area of about 90 square kilometers. The coal in the Meting- Jhimpir area was deposited in Early Eocene age, in the east of Karachi. The coal is enriched in Fe, Zn, Pb, Ni, Cu, Cr, Sb, As, Co, Cd, Mn, Na, K, Ca and Mg. The study also shows that in Meting-Jhimpir coal quartz is dominant mineral and calcite and dolomite as accessory minerals. The comparison of studied coal with Clarke values shows that the coal is slightly enriched with Co, Cr, As, Ca, Mg, and U and Cu, K, Na, Ni, Pb and Zn are depleted.

10

Authors: Imran Ali Jokhio, Sana Hoor Jokhio, Faisal Karim Shaikh

The growing popularity of RFID (Radio Frequency Identification) systems cannot be overlooked due to their wide range of application areas. However, some RFID applications face security and privacy threats due to the exposure of tags over wider distances. There are security methods but these can lack security and scalability when authenticating RF tags in MORIS (Multi Organizational RFID System). RFID systems operating within a single domain have only security and privacy issues due to the security method on tags, but in a multi-organizational system there are even more security and privacy issues in the system architecture rather than just in the security method on tag side. In this paper, we have designed a broker service to EPC (Electronic Product Code) system architecture for secure and confidential data management of the RFID data events. Secure and confidential authentication broker service is an extension to the EPC network architecture for a MORIS. The central authentication broker service ensures to avoid illicit access to the confidential RFID tag's data such as EPC code, whilst managing a large-scale authentication data to ensure secure and deterministic response to the authentic entities of the system.

12

Authors: Fayyaz Hussain Asghar, Muhammad Javed Hyder

Computational analysis of film cooling effectiveness using novel semicircular hole shapes with streamwise inclination of 30o has been carried out. Pitch to diameter ratios of 3.0 has been investigated. Reynolds Averaged Navier-Stoke equation solver FLUENT with standard k- turbulence model is used for simulations. Coolant to mainstream blowing ratios is varied from 1.33-2.0. It is observed that for the streamwise region x/D<20 the centerline and laterally averaged effectiveness values from a row of semicircular holes are higher than that from a row of circular holes due to the less jet lift-off of coolant jet. For a row of semicircular holes, mean coolant jet heights are lower than that from a row of circular holes. Simulations for two rows of inlined and staggered semicircular holes are also carried out and the results are compared with single row of full circular holes. It is found that centerline and laterally averaged effectiveness values from 2 rows of semicircular holes are much higher than a single row of full circular hole case at all streamwise regions at all blowing ratios tested. Among all the cases studied, effectiveness values from two staggered rows of semicircular holes are found to be highest. Jet lift-off is found minimum from two staggered row of semicircular holes. For all cases studied, the mean coolant jet heights from two staggered rows of semicircular holes are found minimum. Results for counter rotating vortex pairs from all cases at plane normal to mainstream

16

Authors: Aamir Hanif, Mohammad AhmedChoudhry, Tahir Mehmood

VSC (Voltage Source Converter) feed-forward control strategy of DVR (Dynamic Voltage Restorer) for an in-phase voltage injection scheme is proposed in this paper to tackle not only voltage sags and swells in the utility supply but also phase jumps as well. The proposed strategy utilizes a time based ramp at a clock rate of 50Hz to obtain a 3-phase reference signal that is compared with actual 3-phase utility voltage to obtain an error signal. If the error in each phase of the utility voltage is greater than zero then appropriate control signals are generated. The switching devices in VSC are switched accordingly to compensate voltage sags, swells and phase jumps in the utility voltage that propagates to load. For the mitigation of voltage sags, swells and phase jumps, the unipolar SPWM control is used. The proposed control system response time to compensate voltage sag, swell and phase jump through switching of VSC devices is less than 10ms whereas ITIC curve and SEMI-F-47 standard suggest a target of 20ms. Load voltage THD is below 5% as per IEEE Std. 519-1992. These results show that employed control strategy has an excellent capability of voltage restoration with acceptable harmonic distortion, within specified time frame for smooth and clean power flow to load. MATLAB®/Simulink® SimpowerSystem tool box has been used to obtain simulation results to verify the effectiveness and validity of the proposed control strategy to improve the quality of the power delivered to the load.