Turbo equalization via constrained-delay APP estimation with decision feedback

We consider turbo equalization for intersymbol interference (ISI) channels, wherein soft symbol decisions generated by the channel detector are iteratively exchanged with the outer error-correction decoder based on the turbo principle. Our work is based on low-complexity suboptimal soft-output channel detection using a constrained-delay (CD) a posteriori probability (APP) algorithm. Central to the proposed idea is the incorporation of effective decision-feedback schemes, which significantly reduce complexity while providing immunity against error propagation that typically plagues decision-feedback schemes. We observe that the effect of decision feedback is quite different on turbo equalization versus traditional, hard-decision-generating and noniterative equalization. In particular, we demonstrate that when the feedback scheme applied is inadequate for the given equalizer parameters and ISI condition, the extrinsic information generated by the equalizer becomes distinctly non-Gaussian, and the quality of soft information, as monitored by the trajectory of mutual information, fails to improve in the iterative process. We identify parameters of feedback-based CD-APP schemes that offer favorable complexity/performance tradeoffs, compared with existing turbo-equalization techniques.     

Two Semi-Empirical Methods for Determination of Shafranov Shift in IR-T1 Tokamak

In this paper we present two semi-empirical methods for determination of Shafranov shift in IR-T1 tokamak. In the first method, solution of the Grad–Shafranov equation present, and one relation for Shafranov shift obtained, also in second method according to magnetic fields distribution around the plasma, second relation for the Shafranov shift obtained. Based on the two methods, four magnetic pickup coils were designed, constructed, and installed on the outer surface of the IR-T1 tokamak chamber and then Shafranov shift determined from them. Results of the two methods are in good agreement with each other.     

A Comparative Study of Three Mapping Methodologies

Map building is one of the core competencies of truly autonomous robots. Numerous techniques have been developed to represent the static and dynamic environments as well as the perceptional sensing frameworks so far. In this paper, on the basis of our previous work, we compare various sensor systems in building the static and dynamic environment map with the segment-based map and Fuzzy-Tuned Grid-Based Map (FTGBM) strategies. From the comparative results of experiments, we propose a probably efficient and trade-off framework which balances the accuracy of the map against the overall system cost.     

Dietary assessment of hemodialysis patients in Tehran, Iran

Inadequate dietary intakes are a major determinant of malnutrition in hemodialysis (HD) patients. Considering the lack of information available on dietary intakes of HD patients in Iran, the present study was designed to assess the dietary intakes of HD patients in Tehran, Iran. For this cross‐sectional study, from among adult HD patients of 50 Tehran hemodialysis centers, 291 patients were randomly selected. Dietary intakes of these patients were assessed using a 4‐day dietary recall. In addition, 4 mL of blood was obtained from each patient before dialysis to measure serum urea, creatinine, albumin, phosphorus, calcium, potassium, and high sensitive C‐reactive protein levels. Dietary intakes of energy, protein and fiber were lower than recommended intakes in 88%, 84.5%, and 99% of HD patients, respectively. There were significant associations between dietary energy intake with the patient's age (p < 0.05), and HD vintage (P < 0.001). In addition, a significant association was found between dietary protein intake and sex (P < 0.05). Intakes of vitamins B1, B2, B3, B6, B12, C, E, folic acid, and of the minerals calcium and zinc (from both the diet and supplements) were lower than recommended intakes in 13.5%, 41.5%, 19%, 66%, 61%, 78%, 77%, 24%, 34%, and 98.5% of HD patients, respectively. Inadequate intakes of energy and various nutrients are prevalent in HD patients in Tehran, Iran, which may contribute to increased morbidity and mortality in these patients. Therefore, nutrition counseling and the administration of vitamin and mineral supplements are necessary in Iranian HD patients.     

Study of the slow-fast preamplifier input parameter’s effects on output image for LYSO scintillator with PS-PMT based animal PET

We developed a small animal positron emission tomography with four detector heads, each one composed of 2 × 2 cm² of pixilated LYSO matrix of 10 × 10 crystals, 2 × 2 mm wide and 10 mm deep coupled to position sensitive photomultiplier (PS-PMT, Hamamatsu R8900U-00-C12). Anger-type logic discretized positioning circuit (DPC) multiplexed readout connected to PMT of each head. The fast-slow preamplifier is used in the fabricated animal PET. We showed that the input capacitance of the preamplifier (the capacitance in the output node of the resistive network) has a direct effect on output image. Image broadening, peak to valley ratio and the geometry distortion of crystal illustration are studied for different input capacitance of preamplifier. The input capacitance of 1 nF resulted in the best image by keeping all the parameters at the proper level with no geometry distortion at the edge of the image.     

Three‐dimensional fatigue crack growth modelling in a helical gear using extended finite element method

In this paper, the fatigue crack growth in helical gear tooth root has been simulated using linear elastic fracture mechanics. The extended finite element method has been used to simulate 3D fatigue crack growth and obtain growth path. Paris equation has been used to calculate the fatigue life of the gear. The modelling time has reduced considerably compared to previous works carried out on 3D crack growth in gears. Some verifications have been carried out to ensure the reliability of the results.     

The Effect of Thermal Radiation on Nanofluid Cooled Microchannels

This article studies thermal analysis of single phase laminar flow nanofluid cooled rectangular microchannel heat sink (MCHS) subject to the uniform wall temperature condition. The solutions for velocity and temperature distributions are obtained from both high-aspect-ratio and low-aspect-ratio microchannels. The practical criterion for the validity of the model are used to express the cases which are assumed to produce inaccuracy in heat transfer prediction, and the participating area of base and tip plates of microchannel in radiation exchange has been defined. Radiation effects of ultra fine particles incorporated in a base coolant fluid, in heat transfer enhancement of nanofluid cooled MCHS are considered, and effects of near field thermal radiation on total heat transfer of micro heat sinks are also investigated.     

Theoretical and Experimental Approach in Poloidal Beta and Internal Inductance Measurement on IR-T1 Tokamak

Measurements of poloidal beta β _p and internal inductance l _i are essential in tokamak plasma research. Much more plasma parameters such as the plasma current density profile, magnetohydrodynamics instability, and plasma energy confinement time are determined by using these parameters. Discrete poloidal magnetic probes along with the diamagnetic loop can be utilized in measurement of the plasma poloidal beta β _p and internal inductance l _i . In this paper, theoretical and experimental results in determining β _p and l _i are presented and discussed.