Robust regulation and tracking system design for multivariable control of the tape transport mechanism

Tape mechanisms must be able to transport the tape with a constant velocity for achieving high rate of data transfer. In this paper, a multivariable model of tape transport mechanism including the take-up and supply reel servos for tape tension control and capstan servo for speed control is considered. To achieve desired performance, pole-placement approach based on general canonical control form (GCCF) is used. Instead of using expensive tension sensors, an observer is designed. A regulator system is developed for disturbance rejection; and a modified integral control is designed for perfect tracking of desired set-points in tape speed and tensions. Since the real dynamic model associates with parametric uncertainties, an algorithm is developed for robust pole-placement. Eigenvalues of the uncertain control system are chosen such that appropriate responses are achieved while control efforts remain small bounded. Results show that robust performance is obtained for uncertain models with various parametric uncertainties.     

Attack containment in mobile ad-hoc networks through fair distribution of processing resources

Due to frequent joining and leaving of nodes and better performance, use of flooding algorithms is always proffered in Mobile Ad-hoc Networks (MANETs). A single query transmitted by a node can be received by hundreds of nodes at 3rd or 4th hop. But it is also fact that flooding algorithms provide an opportunity to attackers for launching query flooding attacks. On one side these query flooding attacks results in wastage of valuable processing resources and on the other side they cause in starvation and delay at legitimate user’s end. To solve this problem we proposed attack containment techniques by providing a fair share of processing resources to every node. Fair distribution is achieved by designing different query distribution techniques based on mathematical models. Results obtained through network simulator 2 prove that the proposed solution is resilient against various types of flooding attacks.     

Investigating data preprocessing methods for circuit complexity models

Preprocessing the data is an important step while creating neural network (NN) applications because this step usually has a significant effect on the prediction performance of the model. This paper compares different data processing strategies for NNs for prediction of Boolean function complexity (BFC). We compare NNs’ predictive capabilities with (1) no preprocessing (2) scaling the values in different curves based on every curve’s own peak and then normalizing to [0, 1] range (3) applying z-score to values in all curves and then normalizing to [0, 1] range, and (4) logarithmically scaling all curves and then normalizing to [0, 1] range. The efficiency of these methods was measured by comparing RMS errors in NN-made BFC predictions for numerous ISCAS benchmark circuits. Logarithmic preprocessing method resulted in the best prediction statistics as compared to other techniques.     

Radioisotope choroid plexography. A preliminary report

Radioisotope plexography seems as easy and innocuous as routine brain scanning. An introductory method is given which could be improved. The choroid plexuses of the four ventricles were well visualized in 15 patients. Consideration is given to the possible labeling process. Besides its morphological value, the test could give interesting clues in the dynamic study of hydrocephalus.     

Preparation of Jute-Plastic Composite by the Preirradiation Method

The jute-plastic composite was prepared by shaking the preirradiated jute fibers (by gamma rays) in a deoxygenated aqueous methyl methacrylate (MMA) solution that contained surfactant and a ho-mopolymer inhibitor. The total dose, dose rate, monomer concentration, reaction time, and temperature were optimized; the jute fibers preirradiated at a 3-Mrad dose at a 100-krad/h dose rate yielded maximum MMA grafting under the above experimental conditions when the jute substrates were shaken for 3 h at 80°C in a deoxygenated 10% MMA aqueous solution containing 1% nonionic surfactant and 0.2% homopolymerization inhibitor. The composite was characterized by infrared and differential scanning calorimetric analyses; the results revealed that preirradiated jute fibers were found to be grafted with MMA in the experimental conditions. The weathering effect and water absorption ability of the composite were determined and found that ungrafted jute samples lost both tenacity and stretchability by the weathering test, whereas the grafted jute samples retained strength (tenacity) even though these were subjected to a severe weathering test up to 105 h. The equilibrium moisture content sharply decreased with an increase in grafting up to the 15% grafting level, after which it was found to be very steady.     

Effect of Glass Transition Temperature (Tg ) in Thermal and Mechanical Properties of UV-Cured Films

Polymers of urethane diacrylate containing an aliphatic or aromatic backbone chain were prepared in the presence of a number of monofunctional and polyfunctional monomers under UV curing. These monomers have different glass transition temperatures ranging from — 110° to 250°C. Film hardness, gel content, tensile properties, and shape recovery characters of these polymers were determined. A correlation between the glass transition temperatures and these properties was established. The monomer N-vinyl pyrrolidone demonstrated the best performance in the preparation of polymers. Some of these polymer films have achieved a unique character of shape recovery phenomenon.     

New liquid crystalline columnar poly(epichlorohydrin‐co‐ethylene oxide) derivatives leading to biomimetic ion channels

A new family of liquid crystalline columnar polyethers was obtained by modification of Poly(epichlorohydrin‐co‐ethylene oxide) (P(ECH‐co‐EO)) with the dendron 3,4,5‐tris[4‐(n‐dodecan‐1‐yloxy)benzyloxy]benzoate, under different conditions. The highest modification degree that we could achieve was 69%. The copolymers were fully characterized by ¹H and ¹³C nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X‐ray diffraction (XRD). All copolymers exhibited liquid‐crystalline columnar behavior whose range of stability depended on the modification degree. X‐ray diffraction experiments on oriented samples showed that the dendrons are approximately perpendicular to the column axis and that their average number per unit cell ranged from 5 to 6. The formation of a stable columnar mesophase in the polyether should determine the presence of a continuous ion channel along the column axis. Therefore, these copolymers are suitable candidates for the preparation of membranes for small cation transport, in agreement with the results that we obtained by using poly(oxy‐1‐chloro methylethylene) (PECH) modified with the same dendron. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers