Entrance surface dose and image quality: comparison of adult chest and abdominal X-ray examinations in general practitioner clinics, public and private hospitals in Malaysia

This study was undertaken to compare the entrance surface dose(ESD) and image quality of adult chest and abdominal X-ray examinationsconducted at general practitioner (GP) clinics, and public andprivate hospitals in Malaysia. The surveyed facilities wererandomly selected within a given category (28 GP clinics, 20public hospitals and 15 private hospitals). Only departmentalX-ray units were involved in the survey. Chest examinationswere done at all facilities, while only hospitals performedabdominal examinations. This study used the x-ray attenuationphantoms and protocols developed for the Nationwide Evaluationof X-ray Trends (NEXT) survey program in the United States.The ESD was calculated from measurements of exposure and clinicalgeometry. An image quality test tool was used to evaluate thelow-contrast detectability and high-contrast detail performanceunder typical clinical conditions. The median ESD value forthe adult chest X-ray examination was the highest (0.25 mGy)at GP clinics, followed by private hospitals (0.22 mGy) andpublic hospitals (0.17 mGy). The median ESD for the adult abdominalX-ray examination at public hospitals (3.35 mGy) was higherthan that for private hospitals (2.81 mGy). Results of imagequality assessment for the chest X-ray examination show thatall facility types have a similar median spatial resolutionand low-contrast detectability. For the abdominal X-ray examination,public hospitals have a similar median spatial resolution butlarger low-contrast detectability compared with private hospitals.The results of this survey clearly show that there is room forfurther improvement in performing chest and abdominal X-rayexaminations in Malaysia.     

A comparison of some model order reduction methods for fast simulation of soft tissue response using the point collocation-based method of finite spheres

In this paper we develop the point collocation-based method of finite spheres (PCMFS) to simulate the viscoelastic response of soft biological tissues and evaluate the effectiveness of model order reduction methods such as modal truncation (MT), Hankel optimal model and truncated balanced realization (TBR) techniques for PCMFS. The PCMFS is a physics-based meshfree numerical technique for real time simulation of surgical procedures. Since computational speed has a significant role in simulation of surgical procedures, model order reduction methods have been compared for relative gains in efficiency and computational accuracy. Of these methods, TBR results in the highest accuracy with an average error which is within 3.37% of the full model while MT results in the highest efficiency with a computational cost reduction of 54.2% compared to the full model.     

Reducing electrode wear ratio using cryogenic cooling during electrical discharge machining

In this study, cooling effect of copper electrode on the die-sinking of electrical discharge machining of titanium alloy (Ti-6Al-4V) has been carried out. Investigation on the effect of cooling on electrode wear and surface roughness of the workpiece has been carried out. Design of experiment plan for rotatable central composite design of second order with four variables at five levels each has been employed to carry out the investigation. Current intensity (I), pulse on-time (t _on), pulse off-time (t _off), and gap voltage (v) were considered as the machining parameters, while electrode wear and surface roughness are the responses. Analysis of the influence of cooling on the responses has been carried out and presented in this study. It was possible to reduce electrode wear ratio up to 27% by electrode cooling. Surface roughness was also reduced while machining with electrode cooling.     

Polymer Nanocomposite Membranes of Sulfonated Poly(Styrene‐Isobutylene‐Styrene) With Sulfonated Graphene Oxide for Fuel Cell and Protective Clothing Applications

Graphene oxide (GO) and its sulfonated analog (sGO) have been incorporated into sulfonated poly(styrene‐isobutylene‐styrene) (SO₃H SIBS) in order to enhance its water retention and proton conductivity, while aiming to block permeant passage through the material. The polymer nanocomposite membranes (PNMs) were tested for two applications: direct methanol fuel cell and chemical and biological protective clothing. The transport properties of the membranes were determined as a function of SIBS sulfonation level (i.e., 37, 61, and 88 mol%), filler type (i.e., GO and sGO) and filler loading (i.e., 1, 3, 5, and 10 wt%). Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the functionalization and incorporation of the fillers into SO₃H SIBS. No significant changes were observed in the thermal stability or FTIR spectra of the PNMs after addition of the fillers. Dissimilar behaviors were observed for the ion exchange capacity, water absorption capabilities and transport properties of the membranes after incorporation of the fillers. Atomic force microscopy (AFM) phase images and Fenton's test results indicate that the oxidative stability of the PNMs is associated to the interconnectivity between the hydrophilic domains of the fillers and SO₃H SIBS. The PNMs presented low permeability and high proton conductivity and thus, functioned adequately for both applications. POLYM. ENG. SCI., 59:E455–E467, 2019. © 2018 Society of Plastics Engineers     

Real-Time Frequency Estimation of Complex GMSK Signal of Green Communications Devices

Parameter estimation of signals of universal software radio peripheral (USRP) devices is crucial to solve the problem of phase offsets of received signals in distributed beamforming. For systems that will utilize the closed loop feedback algorithm where the receiver needs to send the received signal strength (RSS) values periodically to the beamforming node so as to take advantage of energy conservation, the frequency and phase of these signals should be estimated before smoothening by nonlinear filters. This article presents the estimation of the frequency offsets of a Gaussian minimum shift keying (GMSK) signal from N210 USRP devices in real time by using the Radix-2 fast Fourier transform (FFT) algorithm in GNURadio. For these green communications devices, most of the needed hardware parts have been software defined, thereby reducing the supposed energy consumption. The frequency offsets from reference carrier frequencies of 900 MHz and 2.4 GHz are less than 3 kHz each before the estimation, but the average offsets are 45 Hz and 100 Hz after the estimation, respectively. The high offset value experienced with the 2.4 GHz carrier was due to consistent interference from devices on that same frequency.     

An Energy-Efficient Hardware Implementation of HOG-Based Object Detection at 1080HD 60 fps with Multi-Scale Support

The end of Dennardian scaling in advanced technologies brought about new architectural templates to overcome the so-called utilization wall and provide Moore’s Law-like performance and energy scaling in embedded SoCs. One of the most promising templates, architectural heterogeneity, is hindered by high cost due to the design space explosion and the lack of effective exploration tools. Our work provides three contributions towards a scalable and effective methodology for design space exploration in embedded MC-SoCs. First, we present the He-P2012 architecture, augmenting the state-of-art STMicroelectronics P2012 platform with heterogeneous shared-L1 coprocessors called HW processing elements (HWPE). Second, we propose a novel methodology for the semi-automatic definition and instantiation of shared-memory HWPEs from a C source, supporting both simple and structured data types. Third, we demonstrate that the integration of HWPEs can provide significant performance and energy efficiency benefits on a set of benchmarks originally developed for the homogeneous P2012, achieving up to 123x speedup on the accelerated code region (～98 % of Amdahl’s law limit) while saving 2/3 of the energy.     

The use of AI methodologies in production system modeling

Managers of production facilities encounter substantial complexities when attempting to utilize formal mathematical methods to support their planning activities. These complexities arise from difficulties in the formulation of production models, their execution via computer based methods, and the interpretation of the results obtained. This paper demonstrates a practical method for providing managers with the tools necessary to deal with these complexities. The method is based on the representation of modeling knowledge via formal logic and its implementation via Prolog.     

CALCULATING THE VISCOSITY OF MIXTURES BY GROUP CONTRIBUTIONS

A group contribution method for predicting the viscosity of binary and ternary liquid mixtures is proposed. Tests of the method against existing literature data show excellent agreement. Parameters for eight groups are presented.     

Think globally act locally approach for the synthesis of a liveness-enforcing supervisor of FMSs based on Petri nets

This paper, by using Petri nets (PNs), reports a general approach, called a think globally, act locally (TGAL) method, to compute liveness-enforcing supervisors (LES) for flexible manufacturing systems (FMSs) prone to deadlocks. A place called global sink/source place (GP) is introduced provisionally help us to decide a set of monitors such that deadlock states can be removed. The TGAL method proceeds with liveness enforcement by an iterative way in which a complete state enumeration is computed at each step. The resulting LES is generally maximally permissive or suboptimal, without solving intractable integer linear programming (ILP) problems. Given a system, a sufficient condition is developed to decide whether the TGAL method can find maximally permissive, that is, optimal supervisors. Several typical FMSs popularly studied in the literature are used as the examples to demonstrate the proposed method.     

3-D finite element modeling of extended single plate shear connections: Predicting the mode of failure

Twisting and lateral-torsional stability of extended shear-plate connections could be a design issue due to the relatively long distance between the weld and the bolt centroid of the shear tab, and the eccentricity between the thickness of the connection plate and web of the supported beam. The 13^th edition of the Steel Construction Manual did not include checks for determining whether or not twisting would have to be considered as a controlling design limit state. However, the current edition (i.e., the 14^th edition) provides a methodology for evaluating the need for stiffeners (also called stabilizer plates) that based on the amount of twisting of the connection plate. This paper presents the results of three-dimensional non-linear finite element analyses of a number of extended single plate connections in which the floor slab, which braces the top flange of the supported member, was incorporated. The primary goal of the reported research was to examine the need for stabilizer plates, and to investigate twist in extended shear tabs.