Image and video compression algorithms based on recovery techniquesusing mean field annealing

Image and video coding algorithms have found a number of applications ranging from video telephony on the public switched telephone networks (PSTN) to HDTV. However, as the bit rate is lowered, most of the existing techniques, as well as current standards, such as JPEG, H. 261, and MPEG-1 produce highly visible degradations in the reconstructed images primarily due to the information loss caused by the quantization process. In this paper, we propose an iterative technique to reduce the unwanted degradations, such as blocking and mosquito artifacts while keeping the necessary detail present in the original image. The proposed technique makes use of a priori information about the original image through a nonstationary Gauss-Markov model. Utilizing this model, a maximum a posteriori (MAP) estimate is obtained iteratively using mean field annealing. The fidelity to the data is preserved by projecting the image onto a constraint set defined by the quantizer at each iteration. The proposed solution represents an implementation of a paradigm we advocate, according to which the decoder is not simply undoing the operations performed by the encoder, but instead it solves an estimation problem based on the available bitstream and any prior knowledge about the source image. The performance of the proposed algorithm was tested on a JPEG, as well as on an H.261-type video codec. It is shown to be effective in removing the coding artifacts present in low bit rate compression     

Determination of Seasonal Changes in Olive Oil by Using Differential Scanning Calorimetry Heating Thermograms

Thermal properties (upon heating) of extra virgin olive oils (EVOOs) from Aegean cultivars were determined to evaluate the possibility of using differential scanning calorimetry (DSC) as a tool for monitoring seasonal changes in chemical composition. Chemical properties of the samples were analyzed to assess the relationship between the thermal properties and chemical properties as well. The thermal properties of Aegean cultivars were found to be influenced by major components (palmitic acid, oleic acid, linoleic acid, triolein and palmitodiolein). The melting offset temperature, the temperature range of melting and the melting enthalpy of Aegean cultivars presented significant differences with respect to crop season (p < 0.05). DSC may be utilized to evaluate compositional changes with respect to crop season.     

Effect of Vanadium-Titanium Co-doping on the BPSCCO Superconductor

We have produced the (BiPb)₂V _x Sr₂Ca₃Cu_4?y Ti _y O_12+?? compounds for x=0.05 and y=0, 0.05, 0.10 and 0.20 by glass-ceramic method. The effects of vanadium adding and Ti doping on the structure have been investigated by electrical resistance, scanning electron micrographs (SEM), XRD patterns and magnetic hysteresis loop measurements. It has been found that the high-T _c superconducting phase, (2223), is formed in the samples annealed at 845?°C for 185, with concentration x=y=0.05. However, with increasing Ti doping the (2223) phase transforms into the (2212) phase. We have observed no superconducting properties for x=0.05 and y=0.20 compound. It has completely transformed to semiconductor. In addition, the critical current densities (J _c), calculated from the hysteresis loop measurements by using Bean??s critical state model are obtained for the samples in the same doping range. Our data have indicated that J _c decreases with increasing temperature and Ti concentration.     

Finite element and experimental investigation of temperature changes on a twist drill in sequential dry drilling

The drilling process is highly non-linear. Coupled with a thermo-mechanical machining, localized heating and temperature increases in the workpiece are caused by the rapid plastic deformation of the workpiece and by the friction along the drill-chip interface. The cutting temperature at the tool-chip interface is an important factor which directly affects workpiece surface integrity, tool wear, and hole diameter and cylindricity in the drilling process. In this study, the effects of sequential dry drilling operations on the drill bit temperature were investigated both experimentally and numerically. Drill temperatures were measured by inserting standard thermocouples into the coolant (oil) hole of TiN/TiAlN-coated carbide drills. Experimental studies were conducted using two different workpiece materials, AISI 1040 steel and Al 7075-T651. The drill bit temperature was predicted using a numerical computation with Third Wave AdvantEdge finite element method (FEM) software, which is based on Lagrangian explicit. The results obtained from the experimental study and finite element analyses (FEA) were compared. Reasonable agreement between the measured and calculated drill bit temperature results were found for sequential dry drilling.     

Selection of optimal cutting conditions by using GONNS

Machining conditions are optimized to minimize the production cost in conventional manufacturing. In specialized manufacturing applications, such as micro machining and mold making, achievement of specific goals may be the primary objective. The Genetically Optimized Neural Network System (GONNS) is proposed for the selection of optimal cutting conditions from the experimental data when analytical or empirical mathematical models are not available. GONNS uses Backpropagation (BP) type neural networks (NN) to represent the input and output relations of the considered system. Genetic Algorithm (GA) obtains the optimal operational condition by using the NNs. In this study, multiple NNs represented the relationship between the cutting conditions and machining-related variables. Performance of the GONNS was tested in two case studies. Optimal operating conditions were found in the first case study to keep the cutting forces in the desired range, while a merit criterion (metal removal rate) was maximized in micro-end-milling. Optimal operating conditions were calculated in the second case study to obtain the best possible compromise between the roughness of machined mold surfaces and the duration of finishing cut. To train the NNs, 81 mold parts were machined at different cutting conditions and inspected.     

Examination of the movement of a woven fabric in the horizontal direction using a non-contact end-effector

The handling process of a single ply of cotton woven fabrics from a stack in the textile industry is done by workers. Cost-effective automatic handling of the fabrics is becoming an increasingly important issue to reduce the unit cost of the final product .In this study, transporting speeds in the horizontal direction of the woven fabrics were investigated using a non-contact end-effector. A Cartesian robot, which has an x and z axis, was used for handling the cotton woven fabrics. The movement process of a single woven fabric ply from a stack was experimentally shown to find out percentage of success rate of the system. Although the experiments were restricted with small square fabric plies of 100 mm×100 mm sizes, this process could also be applied for products with different shapes.     

Basic computational tools and mechanical hardware for torque-based diagnostic of machining operations

In the industry, only rotary dynamometers can be used for monitoring when multiple spindles are used in machining operations. The current commercial rotary dynamometers are bulky and expensive for most machining centers. The basic hardware and computational tools proposed are for a smaller, more cost effective Torque-based Machining Monitor (TbMM). The objective of the TbMM concept is to estimate the remaining tool life, detect chatter from the torque signal inside the proposed device, and communicate with the central computer only when problems arise. The remaining tool life estimation and chatter detection algorithms of the TbMM were developed by analyzing the experimental data collected by a commercial rotary dynamometer. The mechanical hardware of the TbMM was designed to generate voltage proportional to the cutting torque using a piezoelectric composite element. The remaining tool life was estimated from the standard deviation (or variance) of the torque signal. Teager-Kaiser algorithm (TKA) based procedure detected the chatter based on the frequency estimations only from four samples at a time. The accuracy and characteristics of the signal of the mechanical component of the TbMM were found satisfactory in the estimation of machining problems such as wear and chatter. The TbMM is a good choice particularly when multiple spindles work simultaneously on the same workpiece.     

Cash-back rewards versus equity-based electronic loyalty programs in e-commerce

Loyalty is a crucial part of today’s business because retaining a customer is generally less expensive than attracting a new one. This relationship also holds true in e-commerce. Most of the e-loyalty programs available on the Internet utilize cash-back rewards. A new type of e-loyalty program in which customers are offered a fraction of merchant firm’s equity is emerging recently. The profitability of this approach versus cash-back reward programs is still an open question. In this paper, we first survey current e-loyalty programs, and then develop a two-period duopoly model in which one of the firms gives customers a small fraction of its equity and the other offers cash-back reward for a purchase. We derive analytical conditions to compare the total profits generated through each loyalty program. In particular, we find that equity-based e-loyalty programs provide higher total profits than those of cash-back programs in markets where it is difficult for customers to switch between firms. We are grateful for the valuable comments and suggestions by the participants of the AMCIS 2004 Doctoral Consortium, New York City; the Big Ten IS Research Consortium 2004 at the Michigan State University; EURO/INFORMS 2003, Istanbul, Turkey; WISE 2002, Barcelona, Spain; and ICTEC 2002, Montreal, Canada. We are also indebted to the faculty at the Krannert Graduate School of Management for their indispensable inputs.     

Comparison of bursting pressure results of LPG tank using experimental and finite element method

In this study, the resistance of liquefied-petroleum gas (LPG) tanks produced from carbon steel sheet metal of different thicknesses has been investigated by bursting pressure experiments and non-linear Finite Element Method (FEM) method by increasing internal pressure values. The designs of LPG tanks produced from sheet metal to be used at the study have been realized by analytical calculations made taking into consideration of related standards. Bursting pressure tests have been performed that were inclined to decreasing the sheet thickness of LPG tanks used in industry. It has been shown that the LPG tanks can be produced in compliance with the standards when the sheet thickness is lowered from 3 to 2.8mm. The FEM results have displayed close values with the bursting results obtained from the experiments.     

Effect of Bleaching on Roughness of Dental Composite Resins

This study investigated the effect of three bleaching agents (Whiteness Perfect, Whiteness Super, Whiteness HP) on roughness of three dental resin composites (Admira, Durafill VS, Gradia Direct). Twenty disk-shaped standard specimens (10 × 2 mm) of each composite material were prepared and divided into four subgroups (n = 5). In each resin composite group, the unbleached specimens served as control; the other specimens were bleached with one of the bleaching agents according to the manufacturer's instruction. Roughness values were assessed using the atomic force microscope and metallographic microscope. Two-dimensional and 3D images were also taken for detecting surface alterations of each specimen group. Although the surfaces of all specimens did not seem to be smooth, the unbleached control specimens showed more irregular areas compared with those of the bleached ones. Roughness values were decreased in bleached groups to some extent depending on the bleaching agents used.