Showing papers by "Universiti Teknologi Petronas published in 2007"

On the security defects of an image encryption scheme.

Abstract: This paper studies the security of a recently-proposed chaos-based image encryption scheme, and points out the following problems: 1) there exist a number of invalid keys and weak keys, and some keys are partially equivalent for encryption/decryption; 2) given one chosen plain-image, a subkey K10 can be guessed with a smaller computational complexity than that of the simple brute-force attack; 3) given at most 128 chosen plain-images, a chosen-plaintext attack can possibly break the following part of the secret key: fKi mod 128g 10=4 , which works very well when K10 is not too large; 4) when K10 is relatively small, a known-plaintext attack can be carried out with only one known plain-image to recover some visual information of any other plain-images encrypted by the same key.

Detection of level of satisfaction and fuzziness patterns for MCDM model with modified flexible S-curve MF

Abstract: The present research work deals with a logistic membership function (MF), within non-linear MFs, in finding out fuzziness patterns in disparate level of satisfaction for Multiple Criteria Decision-Making (MCDM) problem. This MF is a modified form of general set of S-curve MF. Flexibility of this MF in applying to real world problem has also been validated through a detailed analysis. An example illustrating an MCDM model applied in an industrial engineering problem has been considered to demonstrate the veracity of the proposed technique. The approach presented here provides feedback to the decision maker, implementer and analyst and gives a clear indication about the appropriate application and usefulness of the MCDM model. The key objective of this paper is to guide decision makers in finding out the best candidate-alternative with higher degree of satisfaction with lesser degree of vagueness under tripartite fuzzy environment.

Liquid-Liquid Equilibrium of Poly(ethylene glycol) 2000 + Potassium Citrate + Water at (25, 35, and 45) °C

Abstract: Liquid−liquid equilibrium for an aqueous two-phase system containing poly(ethylene glycol) 2000 + potassium citrate + water was studied at three different temperatures of (25, 35, and 45) °C. The binodal curve was fitted to an empirical equation relating the concentrations of PEG 2000 and potassium citrate, and the coefficients were estimated for the respective temperatures. Tie line compositions were correlated using Othmer−Tobias and Bancroft equations, and the parameters are also reported.

Evolutionary artificial neural network for selecting flexible manufacturing systems under disparate level-of-satisfaction of decision maker

Abstract: This paper proposes the application of Meta-Learning Evolutionary Artificial Neural Network (MLEANN) in selecting the best flexible manufacturing systems (FMS) from a group of candidate FMSs. Multi-criteria decision-making (MCDM) methodology using an improved S-shaped membership function has been developed for finding out the "best candidate FMS alternative" from a set of candidate-FMSs. The MCDM model trade-offs among various parameters, viz., design parameters, economic considerations, etc., affecting the FMS selection process under multiple, conflicting-in-nature criteria environment. The selection of FMS is made according to the error output of the results found from the proposed MCDM model.

Extraction and reconstruction of retinal vasculature.

Abstract: Information about retinal vasculature morphology is used in grading the severity and progression of diabetic retinopathy. An image analysis system can help ophthalmologists make accurate and efficient diagnoses. This paper presents the development of an image processing algorithm for detecting and reconstructing retinal vasculature. The detection of the vascular structure is achieved by image enhancement using contrast limited adaptive histogram equalization followed by the extraction of the vessels using bottom-hat morphological transformation. For reconstruction of the complete retinal vasculature, a region growing technique based on first-order Gaussian derivative is developed. The technique incorporates both gradient magnitude change and average intensity as the homogeneity criteria that enable the process to adapt to intensity changes and intensity spread over the vasculature region. The reconstruction technique reduces the required number of seeds to near optimal for the region growing process. It a...

Crescimento, produtividade, caracterização e composição química da aveia branca

Abstract: One experiment was carried out at Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, State of Sao Paulo, with the purpose of evaluating growth, productivity, morphological and phenological characteristics and chemical composition of white oat ( Avena sativa L. cv. UPF 7). The treatments were conducted during cutting times each 14 days, in a random design with three replications. A quadratic effect of time was observed on dry matter and crude protein accumulation, reaching maximum values at maturation (12,240 kg ha -1 ) and at 98 days after emergence (DAE) (818 kg ha -1 ), respectively. Crude protein concentration and in vitro dry matter digestibility (IVDMD) decreased with the time from 24.9 and 82.2% at 14 DAE to 4.9 and 36.8% at maturation, respectively. At 70 DAE, IVDMD was 68%, dry matter production was 3693 kg ha -1 , plants height was 63 cm, CP, Ca and P were 18.9, 0.28 and 0.37% respectively. The optimum availability of forage estimated for 37 DAE through polynomial regression was 1,500 kg ha -1 (dry matter production), and at this time the forage showed the following characteristics: height of 33 cm, 21.4% CP, 0.4% P, 0.27% Ca and 75.5% IVDMD. The time suggested for the utilization of this forage, according to the values of IVDMD and availability of forage varied from 37 to 70 DAE.

A Novel Signal Independent Technique for PAPR Reduction in OFDM Systems

Abstract: New techniques for the reduction of peak to average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems are presented. These techniques are based on precoding the constellation symbols with Zadoff-Chu and generalized chirp-like (GCL) precoders. The proposed techniques can achieve a PAPR reduction of up to 4.5 dB for OFDM systems. The techniques have been shown to be effective and have low complexity

Partition Behavior of Bovine Serum Albumin in PEG2000‐Sodium Citrate‐Water Based Aqueous Two‐Phase System

Abstract: The effect of phase forming components, pH, neutral salt (NaCl) addition on partitioning of bovine serum albumin (BSA) in PEG2000‐sodium citrate based aqueous two‐phase system was investigated at 25°, 35°, and 45°C. The systems were prepared by varying the phase forming components concentration at a pH of 5.0, 6.0, 7.0, 8.0, and 9.0 with different NaCl salt concentrations of 0.05 M, 0.1 M, 1.5 M, 0.2 M, 0.3 M, and 0.4 M. The affinity of the BSA for the lower phase increases with increase in pH, due to increase in ratio of trivalent to divalent citrate ions in the two‐phase system. It was confirmed that the partition of BSA depends on the relative hydrophobicity of the compounds as well as their charge. Optimum level of pH and NaCl concentration for the partitioning of bovine serum albumin was determined.

Evaluation Of Below Bubble Point Viscosity Correlations & Construction of a New Neural Network Model

Abstract: This paper, precisely, evaluates two famous below bubble point viscosity correlations and tries to create a new Neural Network model for estimating this property. The new created model outperforms the two investigated correlations namely Khan Model (1987) and Labedi Model (1992). The new technique (Artificial neural network) found to be successful in developing a model for predicting viscosity below bubble point with an outstanding correlation coefficient of 99.3%. A limited number of data points have been collected from Pakistani fields in order to construct, test, and validate the model. Viscosity from 99 sets of differential liberation data covering a wide range of pressure, temperature, and oil density were used to validate the correlations and to develop the new model. A series of statistical and graphical analysis were conducted also to show the superiority of the model that has been formulated through an Artificial Neural Network technique. A thorough literature review is also made to check the applicability of the existing correlations and their drawbacks.

A Sketch-and-Spray Interface for Modeling Trees

Abstract: We introduce in this paper an interface for modeling botanical trees that we term a sketch-and-spray interface. In using the interface, a user would sketch out various types of strokes to construct the main structures of a tree. A user could use a branch stroke to draw a single branch, a leaf stroke to draw a single leaf or a stem of leaves, or a copy stroke to draw a whole branch together with all its sub-branches and leaves. A user could also use various editing strokes to modify the tree structure. Finally, a user could spray particles upon it to `grow' the overall shape of the tree. We illustrate the utility of our interface using a number of examples throughout this paper.

Sensing degree of fuzziness in MCDM model using modified flexible S-curve MF

Abstract: It is hard to sense the degree of vagueness while using a Multiple Criteria Decision-Making (MCDM) model in industrial engineering problems. Selection of best candidate-alternative is an important issue when the attributes of the candidate-alternatives are conflicting in nature and they have incommensurable units. An MCDM model makes it possible to select the candidate-alternative that suits best for the investor. An example illustrating an MCDM model applied in plant-site selection problem has been considered in this article to demonstrate the veracity of the proposed methodology. The degree of vagueness hidden in the proposed approach has been investigated using a flexible modified logistic membership function (MF). The approach presented here provides feedback to the decision maker, implementer and analyst and gives a clear indication about the appropriate application and usefulness of the MCDM model. The key objective of this article is to guide decision makers in finding out the best candidate-alternative with higher degree of satisfaction and lesser degree of vagueness.

Ornithine decarboxylase expression in the small intestine of broilers submitted to feed restriction and glutamine supplementation

Abstract: Six hundred and forty one-day-old Cobb male broilers were used to evaluate ornithine decarboxylase (ODC) expression in the mucosa of the small intestine. Birds were submitted to early feed restriction from 7 to 14 days of age. The provided feed was supplemented with glutamine. A completely randomized design with a 2 x 2 factorial arrangement was used (with or without glutamine, with or without feed restriction). Restricted-fed birds were fed at 30% the amount of the ad libitum fed group from 7 to 14 days of age. Glutamine was added at the level of 1% in the diet supplied from 1 to 28 days of age. Protein concentration in the small intestine mucosa was determined, and ODC expression at 7, 14, 21, and 28 days of age was evaluated by dot blotting. ODC was present in the mucosa of broilers, and the presence of glutamine in the diet increased ODC activation. Glutamine prevented mucosa atrophy by stimulating protein synthesis, and was effective against the effects of feed restriction. Dot blotting can be used to quantify ODC expression in the intestinal mucosa of broilers.

Iron and manganese amended activated alumina - A medium for adsorption/oxidation of arsenic from water

Abstract: In a laboratory study, iron and manganese amended activated alumina (IMAA) showed promise as an effective medium for removing arsenic [As(III) and As(V)] from groundwater. Batch adsorption/oxidation kinetic test indicated that the effectiveness of the IMAA medium was due to in situ oxidation of As(III) to As(V) and higher adsorption of As(V) by the medium. A home arsenic removal unit, containing 4 L of IMAA or AA and operated at 6 L/h, produced 2400 L and 2340 L or 1392 L and 1320 L of water in two cycles of runs when the influent arsenic concentration was 1.0 mg/L [0.6 mg/L of As(III) and 0.4 mg/L of As(V)]. The IMAA medium should be subjected to field trials to assess the long-term effects on performance, such as loss of medium capacity, attrition of the iron and manganese coating, fouling by organics, and pH and competing ion effects. © IWA Publishing 2007.

Predicting Separation of Lower Hydrocarbon from Natural Gas by a Nano‐Porous Membrane using Capillary Condensation

Abstract: In the present work, the potential of a nano-porous membrane for predicting the separation of lower hydrocarbons from natural gas by capillary condensation was explored. While a gas permeates through a capillary at a suitable pressure, the adsorbed layer may attain a thickness enough to fill the entire membrane pore. Poiseuille flow of the condensed phase follows. Our computed results have established that for a passage through a nano-porous membrane, gas having lower condensation pressure condenses in the pores at a pressure which is about an order of magnitude lower than its vapor pressure at the concerned temperature. In the case of propane/methane and butane/methane binary mixtures, propane and butane are preferentially condensed and permeation rates up to 700 g mol/m 2 s bar for propane and 600 g mol/m 2 s bar for butane have been achieved at a temperature lower than the critical temperature of the permeating species and higher than the critical temperature of the non-permeating species. Since methane has a much lower critical temperature than both propane and butane, it gets physically dissolved in the condensed phase of propane, butane in the case of propane/methane and butane/methane binary mixtures, respectively. An equation of state (EOS) approach has been adopted to calculate the fugacity of methane in the gas, as well as in the condensed phase, in order to estimate its solubility. The Peng-Robinson equation of state was used. Computation of the separation factor for methane/propane and methane/butane was performed over a wide range of temperature, pressure, and gas composition. The separation factor which is expectedly a function of these variables ranged from 0.3-75 for methane/propane and 0.7-140 for methane/butane binary mixtures. It has been established that an acceptable degree of separation is achievable at moderate pressure and at low temperature for the removal of propane and butane from natural gas. The results have the potential to be used for further refinement and optimization of the process conditions so that this strategy can be exploited for large-scale removal of lower hydrocarbon from natural gas at a low cost. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Knowledge based system with embedded intelligent heart sound analyser for diagnosing cardiovascular disorders.

Abstract: Cardiovascular disease (CVD) is the leading cause of death worldwide, and due to the lack of early detection techniques, the incidence of CVD is increasing day by day. In order to address this limitation, a knowledge based system with embedded intelligent heart sound analyser (KBHSA) has been developed to diagnose cardiovascular disorders at early stages. The system analyses digitized heart sounds that are recorded from an electronic stethoscope using advanced digital signal processing and artificial intelligence techniques. KBHSA takes into account data including the patient's personal and past medical history, clinical examination, auscultation findings, chest x-ray and echocardiogram, and provides a list of diseases that it has diagnosed. The system can assist the general physician in making more accurate and reliable diagnosis under emergency conditions where expert cardiologists and advanced equipment are not readily available. To test the validity of the system, abnormal heart sound samples and medical data from 40 patients were recorded and analysed. The diagnoses made by the system were counter checked by four senior cardiologists in Malaysia. The results show that the findings of KBHSA coincide with those of cardiologists.

Effect of the Reciprocating Mass of Slider-Crank Mechanism on Torsional Vibrations of Diesel Engine Systems

Abstract: The torsional vibration phenomenon in the running gear of reciprocating engine systems is usually dealt with by considering a series of constant inertias connected by sections of massless shafting. However in reality, a slider crank mechanism is a vibrating system with varying inertia because the effective inertia of the total oscillating mass of each crank assembly varies twice per revolution of the crankshaft. Large variations in inertia torques can give rise to the phenomenon of secondary resonance in torsional vibration of modern marine diesel engines which can not be explained by conventional theory incorporating only the mean values of the varying inertias. In the past associated secondary resonances and regions of instability tended to be dismissed by most engineers as interesting but of no importance. The situation changed in recent years since there is evidence of the existence of the secondary resonance effects which could have contributed to a number of otherwise inexplicable crankshaft failures in large slow speed marine engines. The cyclic variation of the polar moment of inertia of the reciprocating parts during each revolution causes a periodic variation of frequency and corresponding amplitude of vibration of reciprocating engine systems. It also causes an increase in the speed range over which resonance effects are experienced and only a partial explanation of the behaviour of the systems has been worked out. It is impossible to avoid these instabilities by changes in the design, unless of course the variations in mass and spring constant can be made zero. In the present paper a critical appraisal of the regions of instability as determined from the equation of motion which takes into account variation of inertia is given. The motion in the form of complex waveforms is studied at different speeds of engine rotation. A comparison of theoretical results with Goldsbrough’s experimental results and Gregory’s analysis is included.

Feedback linearized strategies for collaborative nonholonomic robots

Abstract: Collaborative wheeled mobile robots are not stable around a point by continuous time-invariant feedback. Therefore, linear control is ineffective and innovative design techniques such as feedback linearization are required. This paper presents feedback linearized control strategies for collaborative nonholonomic robots using leader-follower formation. A framework for collaborative robots is developed based on their kinematics. The development framework relies on robots having communication capabilities instead of visual capabilities. The collaborative robot system is modeled using Simulink. From the simulation results, the full state linearized via dynamic feedback strategy for the leader robot globally stabilizes the system. Furthermore, the full state linearized via dynamic feedback strategy achieves postures stabilization for the leader-follower formation. For the follower robots, the input-output via static feedback linearized control strategies minimize the error between the desired and actual formation. Furthermore, the input-output linearized control strategies allow dynamical change of the formation at run-time. Thus, for a given feasible trajectory, the full state feedback linearized strategy for the leader robot and input-output feedback linearized strategies for the follower robots are found to be more efficient in stabilizing the system.

Evaluating the effectiveness of digital storytelling with panoramic images to facilitate experience sharing

Abstract: Technology advancement has now enabled experience sharing to happen in a digital storytelling environment that is facilitated through different delivery technologies such as panoramic images and virtual reality. However, panoramic images have not being fully explored and formally studied especially to assist experience sharing in digital storytelling setting. This research aims to study the effectiveness of an interactive digital storytelling to facilitate the sharing of experience. The interactive digital storytelling artifact was developed to convey the look and feel of Universiti Teknologi PETRONAS through the panoramic images. The effectiveness of digital storytelling through panoramic images was empirically tested based on the adapted Delone and McLean IS success model. The experiment was conducted on participants who have never visited the university. Six hypotheses were derived and experiment showed that there are correlations between user satisfaction of digital storytelling with panoramic images and user's individual impact of the application to assist experience sharing among users. Hence, this research concludes a model on the production of an effective digital storytelling with panoramic images for specific experience sharing to bloom among users.

Fuzzy Multi-object Linear Programming Application in Product-Mix Decision-Making

Abstract: This paper focuses on optimizing product-mix problem using real-world data of a food processing industry. The extensively used LP model has been remodeled using fuzzy sets and applied to the real-world problem. The developed LP model is able to consider the fuzziness in the parameters and to tackle the presence of multiple objective functions. The degree of satisfaction of the product-mix decision-maker in terms of (i) the total profit obtained and (ii) the waste resulted, is at least 70%, which is encouraging

Using Singularity Spectrum Attributes for Analyzing Homogeneity/Heterogeneity of Reservoir

Abstract: Over the last decade, spectral decomposition techniques have greatly improved seismic interpretation in the exploration of hydrocarbons. Significant efforts have been directed to the development of such methods for tuning hydrocarbon reservoirs, thin beds and channel estimation. Geological and geophysical changes of the earth formation manifest as discontinuities in a seismic trace. These discontinuities also called singularities thus carry most of the information in the trace. Statistical techniques are required to analyze these discontinuities in order to ascertain the variation in the fluid flow. This paper discusses a technique for detecting reservoir homogeneity/heterogeneity based on singularity spectrum attributes. Singularity spectrum determined from multifractal analysis, can globally describe the singularity content of a signal. Obtaining the singularity spectrum of signals also helps in the identification and classification of different state changes in a signal. The developed technique is applied on synthesized seismograms and two attributes of the singularity spectrum namely correlation dimension and width are determined. Results show that by using these attributes the heterogeneity or homogeneity of the reservoir can be evaluated. Such attributes can increase the reliability of suspected hydrocarbon zones; hence unravelling drilling uncertainties and is potentially useful for reservoir fluid flow modelling.

Parallelization of prime number generation using message passing interface

Abstract: In this research, we proposed a parallel processing algorithm that runs on cluster architecture suitable for prime number generation. The proposed approach is meant to decrease computational cost and accelerate the prime number generation process. Several experimental results are shown to demonstrate the viability of our work.

Enhanced cycling properties of transition metal molybdates, LixM2(MoO4)3 {0≤x<3} [M=Co,Ni] : a nanocomposite approach for lithium batteries

Abstract: Nanocomposite electrodes of recently identified polyanion cathode materials comprising LixM2(MoO4)3 {0 ≤ x < 3} [M = Co, Ni] and nanosized carbon having ~10 nm particle size were found to show remarkable improvement in their discharge capacity compared to the one prepared with acetylene black. The addition of nanosized carbon as a conductive additive offered improved initial discharge capacity of 121 mAh/g between 3.5–2.0 V vs Li/Li. The cause for such an increase could be firmly attributed to the filling up of the grain–grain contact area of the active material, facilitating the intimate grain–grain contacts in the composite structure leading to enhanced capacity delivery. As for the nanocomposite LixCo2(MoO4)3, it was found that at least 55% of its first discharge capacity was retained at the end of 20th cycle compared to its analogous counterpart, LixNi2(MoO4)3.

An Efficient Hybrid Chaotic Image Encryption Scheme

Abstract: In recent years chaotic cryptography has attracted significant attraction for multimedia security. However, most of these chaotic ciphers still suffer from excessive computation for a given level of security [1–3]. In view of these, a novel scheme is proposed in this paper to encrypt digital images that has far smaller computational load. The proposed scheme is based on multiple-piecewise linear chaotic maps (m-PLCMs) and S-box, where the R, G and B channels of digital images are first segmented into low correlated frames of the appropriate length. Identical chaotic key stream is used for the various frames of the R, G and B channels of the segmented image. The reuse of the chaotic stream reduces the computational complexity by a higher factor and the combination of S-box makes it infeasible to extract the chaotic stream due to its low differential and linear probabilities. The analysis of the proposed scheme proves that it efficiently fulfills the tradeoff between security and encryption speed

Modeling of high speed vehicle for path following and obstacles avoidance

Abstract: This research aims to develop a controller that has the ability to control high speed vehicle in avoiding obstacles while following prescribed path as accurately as possible. Every instant, the vehicle decides by itself how to modify its direction according to its environment. Each obstacle is represented independent of the others as a bell-shaped hump by the Gaussian functions which serve as an obstacle recognition system. Multi-objective cost function is formed for the planning strategy to generate, evaluate and select plans so that the vehicle can select which direction to move. Neural network and optimal preview controllers are utilized to control a full linear steering model of a vehicle to increase path following accuracy. To conduct the specified works, MATLAB software was extensively used. Simulated obstacle avoidance has confirmed the capability of a vehicle to precisely avoid collision with obstacles while traveling on high speed along its predetermined path.

XMLTemplate: framework that minimizes the number of software components

Abstract: Extensible Markup Language (XML) is a technology that has been widely used in many areas. This paper proposes a framework that uses XML document to minimize the number of components used in a Web-based application. This decrease in component number is achieved by replacing subclasses with XML document that contains the user interface information which helps create the user interface. The proposed method is applied on a Lecturer's Publication Monitoring System (LPMS) project and a comparison between the framework and normal implementation is done based on this project.

Enabling interoperability between mobile IM and different IM applications using Jabber

Abstract: The two most popular text-messaging systems nowadays are Instant Messaging (IM) and Short Messaging System (SMS). IM runs in computers, where SMS runs through mobile phones. Nowadays, there are numerous efforts done to merge the functionalities of IM into mobile phone. This is due to the fact that IM can provide "presence" of users and less costly. In order to provide the best satisfaction to its users, the mobile IM should be able to communicate to multiple IM service providers. In relation to that, this paper presents the research conducted to develop a mobile IM named Message Conveying System (MCS) that allows it to enable communication with other IM service providers. This was made possible through the implementation of Jabber protocol in MCS, which results in its interoperability with other Jabber-based IM service providers. The MCS was tested to be successfully run on the mobile phone and communicate with the other two Jabber-based IM service providers; Psi and Spark.