MC Model Research Articles

Robust adaptive beamforming with low sensitivity for mutual coupling based on auxiliary elements

The performance of the conventional adaptive beamformer undergoes degradation in the presence of the mutual coupling between the neighbouring elements. To eliminate the sensitivity for the MC, the dummy elements are fixed around the array. Here, the authors demonstrate the optimal layers of auxiliary elements for uniform rectangular array (URA) in the case of the specific MC model and give the concrete theoretical proof. The corresponding derivation proves that only one layer of auxiliary elements is needed to tackle with the MC effect, and the output SINR and beampattern are improved by means of the proposed method for URA. Finally, the simulation results have shown the effectiveness of authors’ method.

Increasing ecoliteracy and student creativity in waste utilization by usingmodels in project based learning social studies learning

<span lang="EN-ID">This study aims to determine the increase in ecoliteracy and creativity in waste utilization by using a project-based-learning (PBL) model in social studies learning. This research is a classroom action research (Action Research). The design of the action model used is the Kemmis and Mc model. Taggart. This research was conducted in the fifth grade (V) of Primary Schools. Data collection techniques used in the study were observation sheet, interview, documentation, and field notes instruments. The results of this study showed that there was an increase in ecolithicacy ability.</span><span lang="EN-ID">Based on the results of the pretest conducted on December 17, 2018, it can be seen that students in Telajung 02 Public Elementary School have not had the ability of Ecoliteracy and students' creativity in utilizing waste. Of the 32 students, the highest score that can be obtained is only 40 from a maximum score of 100. While the lowest value obtained is 20 from a maximum score of 100. In the first cycle, around 63% of students classified as having high ecoliteration ability, 9% classified as having the low ecoliteration ability and 28% classified as having the very low ecoliteration ability. </span><span lang="EN-ID">In cycle II, there was an increase, around 90% of students classified as having high ecoliteration ability, 6% classified as having the low ecoliteration ability and 4% classified as having low ecoliteration ability. </span><span lang="EN-ID">The average value of ecoliteration ability in the first cycle was 87.6 and the second cycle increased to 78.2. In addition, students become more active in the learning process and more courageous in expressing their opinions. This shows that the ecoliteracy and creativity of students can be improved through the project-based-learning model.</span>

Computed tomography x-ray characterization: A Monte Carlo study

The Monte Carlo method is a powerful tool for investigating the characteristics of x-ray beams in diagnostic radiology. An accurate CT MC simulation typically requires a detailed description of the scanner under investigation, including specifications of the photon energy spectrum, the bowtie and inherent filtration design, and the geometry of the scanner (focal spot to isocenter distance, fan angle). Modern CT dosimetry is substantially informed by data produced using Monte Carlo radiation transport techniques. In order to achieve desired levels of accuracy, methods require a good model of the x-ray spectrum used. It has been shown that x-ray spectrum modeling can produce adequate spectra if both the tube potential and the HVL of the x-ray beam are known [1]. Therefore, for accurate CT dosimetry, characterization of the HVL of the CT scanner is necessary. In this work the Phillps® provided the spectrum of Brilliance 64 scanner. The purpose of this work is evaluating all data send by the manufacturer in the way to obtain a spectrum that can be used in Monte Carlo simulations to estimate organ dose or other dosimetric quantities. The EGSnrc MC code was used to evaluate the HVL obtained with the spectrum provided by the manufacturer. The cavity code was used for these simulations and variance reduction techniques were used. The HVL of our MC models were benchmarked against experimental data. The authors found that the HVL of the MC simulations agreed well with the manufacturer-specified data within 1–5% on average for the scanner. This study may be useful to establish a patient-specific dosimetry for the Phillips Brilliance 64 CT systems.

ESTIMATION OF THE ANISOTROPY EMISSION OF LPN/CIEMAT NEUTRON SOURCES: EFFECT OF HEAVY CAPSULE HOLDERS.

In order to estimate the anisotropy emission of 241Am-Be and 252Cf neutron sources from the Spanish Neutron Standards Laboratory (LPN/CIEMAT) detailed models of sources capsules and capsule holders were designed with the MCNPX code. Simulations of the sources inside the capsules without the capsule holders were done to validate the MC model by comparison with experimental results provided by other authors. After that, the capsule holders were incorporated to the simulation. In general, a good agreement has been found between measurements and our calculations. Results show the additional encapsulations have significant influence on anisotropy factors, energy spectra and dose rates.

A modified grain growth Monte Carlo algorithm for increased calculation speed in the presence of Zener drag effect

In its basic implementation, the grain growth Monte Carlo Potts algorithm is repeated millions of times in random matrix positions by using random number generator. The probability for possible site reorientation is bigger for a subset of lattice sites, and the remaining sites are rarely tested. However this method requires a long calculation time for large lattice systems. To increase the calculation speed for grain growth simulation, one proposes two modifications to the classical MC model. First, all lattice sites will be tested for reorientation at random with the same probability, i.e. without repetition for every Monte Carlo step. Second, the site energy will be divided by a parameter that represents the effective force acting on grain boundaries in the presence of particles. The second modification accelerates the growth of large grains to the detriment of neighboring small grains. The efficiency of these modifications has been tested for grain growth with the presence of Zener drag effect and its absence.

Accelerating Synchronization Using Moving Compute to Data Model at 1,000-core Multicore Scale

Thread synchronization using shared memory hardware cache coherence paradigm is prevalent in multicore processors. However, as the number of cores increase on a chip, cache line ping-pong prevents performance scaling for algorithms that deploy fine-grain synchronization. This article proposes an in-hardware moving computation to data model (MC) that pins shared data at dedicated cores. The critical code sections are serialized and executed at these cores in a spatial setting to enable data locality optimizations. In-hardware messages enable non-blocking and blocking communication between cores, without involving the cache coherence protocol. The in-hardware MC model is implemented on Tilera Tile-Gx72 multicore platform to evaluate 8- to 64-core count scale. A simulated RISC-V multicore environment is built to further evaluate the performance scaling advantages of the MC model at 1,024-cores scale. The evaluation using graph and machine-learning benchmarks illustrates that atomic instructions based synchronization scales up to 512 cores, and the MC model at the same core count outperforms by 27% in completion time and 39% in dynamic energy consumption.

Determination of 137Cs content in fuel assemblies of a zero power reactor by Monte Carlo based efficiency calibration

In the Training Reactor of the Budapest University of Technology and Economics EK-10 fuel assemblies are applied and some slightly irradiated EK-10 fuel assemblies are stored as spare fuel. These fuel assemblies were used in a critical assembly in the first part of 1970s. Due to the lack of exact data related to the power history of these assemblies the long-lived fission product (137Cs) content was determined by gamma spectrometry. Some fuel assemblies were measured in a predetermined geometric arrangement using a portable Canberra GX2518 XtRa coaxial type HPGe semiconductor gamma detector. In order to determine the energy dependent detection efficiency function for this rather complex measuring geometry Monte Carlo model was constructed. For calculation of the specific activities of radioisotopes located in the fuel assemblies MCNP6 transport code was applied. The MC simulation model such as the material composition of fuel rods, cladding and the exact geometry of fuel assemblies were designed by original documents of EK-10 fuel assembly. The MC model calculation was verified by the measured intensities of the gamma lines emitted by 235U isotope and of the gamma lines of the daughter elements of 238U.

Three-dimensional numerical simulation of pile-twin tunnels interaction – Case of the Shiraz subway line

The use of an underground transportation network to solve urban traffic problems is a practical solution. Shiraz, one of the most famous touristic cities of Iran, is developing its own urban railway network using mechanized twin tunnels. It is almost inevitable for tunnels to pass nearby an existing pile foundations. In this study, a three-dimensional numerical model was developed to investigate the pile-tunnel interaction. All the mechanized excavation phases of an EPB-TBM (Earth pressure balance, Tunnel boring machine) and the segmental lining were modeled using a finite difference code. The role of the Constitutive soil’s model is also investigated by using both a linear elastic-perfectly plastic one (failure criteria of Mohr-Coulomb type) named as MC and a nonlinear perfectly plastic one the Cap-Yield (CYsoil) constitutive model. Two different scenarios were considered: the influence of tunneling on existing piles and the impact of installing bridge piles nearby existing twin tunnels. The influence of the soil/structure interaction is presented in terms of surface settlements, forces induced in the tunnel lining and forces along the piles. It should be noted that on the base of the obtained results, the MC model cannot accurately estimate the ground settlements and the forces in tunnel and piles, therefore it is necessary to use advanced constitutive models like CYsoil for design purposes.

SIMULATION OF OSL AND TLD DOSEMETER RESPONSE FOR THE DEVELOPMENT OF NEW EXTREMITY DOSEMETERS.

The individual monitoring service at the Helmholtz Zentrum München is currently developing a new eye lens dosemeter to be integrated in radiation protection glasses and a new ring dosemeter using a new BeOSL detector element for extremity dosimetry developed by Dosimetrics. In the design process for the new eye lens dosemeter, MCNP6 Monte Carlo simulations were used to model the energy and angular response of new dosemeters before ordering the expensive tools for injection molding. This study describes the simulation of the dosemeter and detector, and the involved calculations do obtain the response in terms of the radiation protection quantity Hp(3). Simulations were carried out also for existing whole body dosemeters and TLD rings in order to verify the MC tools. With the final dosemeter prototypes becoming available earlier this year, all MC models could be verified and show very good agreement with experimental data.

PENERAPAN METODE PEMBELAJARAN ROLE PLAYING UNTUK MENINGKATKAN SIKAP TOLERANSI KERAGAMAN SUKU BANGSA DAN BUDAYA KELAS V

This study is based on the problems found in the fifth grade of SD Negeri Rahayu, namely: (1) students' tolerance is still low; (2) the social studies learning process still takes place in a classical manner (Teacher Center); and (3) lack of utilization of learning models / methods. Thus the purpose of this study are: (1) to describe how the activities of students in learning the tolerance attitude of ethnic diversity and culture by applying the method of role playing; and (2) to describe an increase in the ability of tolerance of class V students by applying the role playing method in learning. The research method used is Classroom Action Research (CAR) with the design of the Kemmis and MC models. Taggart is carried out for two cycles starting from the stages of planning, implementation, observation, and reflection. The subjects in this study were class V SD Negeri Rahayu 2018/2019 academic year, totaling 28 students. The instruments used to collect data in this study are: (1) observation sheet; and (2) questionnaire. The results of the study showed that: (1) in general the activities of fifth grade students in learning Social Sciences regarding the tolerance attitude of ethnic and cultural diversity experienced positive development. This is based on the average activity of students in the first cycle, which is 56% and in the second cycle increases to 90%; and (2) in general the increase in tolerance of ethnic groups and the culture of class V students by using the role playing method in learning Social Sciences experienced positive development. This is based on N-Gain data in cycle I, o, 38 and in cycle II it increases to 0.58. The percentage completeness data obtained in the first cycle is 86%, after reflecting and following up on cycle II it increases very well to 100%.

Production performance of largemouth bass Micropterus salmoides and water quality variation in monoculture, polyculture and integrated culture

A 74‐day experiment was conducted to evaluate the production performance and water quality variation in three types of farming system for largemouth bass Micropterus salmoides. The tested aquaculture models included monoculture of largemouth bass (MC), polyculture of largemouth bass, gibel carp Carassius auratus gibelio and silver carp Hypophthalmichthys molitrix (PC), and integrated culture of largemouth bass, gibel carp, silver carp and freshwater pearl mussel Hyriopsis cumingii (IC). The ratio of largemouth bass, gibel carp and silver carp was 30:2:1 in the PC model, and the ratio of largemouth bass, gibel carp, silver carp and mussel was 30:2:1:5 in the IC model. The largemouth bass were fed with formulated feed twice daily. No significant differences were found in weight gain and yield of largemouth bass, total fish yield, nitrogen (N) and phosphorus (P) utilization efficiencies, N and P wastes, pH, nitrite, nitrate, reactive phosphate, total nitrogen, total phosphorus, total organic carbon, chemical oxygen demand, 5‐day biochemical oxygen demand, chlorophyll a, primary productivity among the MC, PC and IC models. The ammonia was lower, while the dissolved oxygen was higher in the PC tanks than in the MC tanks. These results suggest that the environment situation was better in the PC tanks relative to that in the MC tanks. The present study reveals that the PC model should be a way to optimize the aquaculture model for commercial largemouth bass farming.

Dosimetric pitfalls in the application of shielding disk in breast intraoperative electron radiation therapy

Introduction: Intraoperative electron radiotherapy (IOERT) is an IORT technique in which electron beams with different nominal energies are used for irradiation of microscopic residual of tumor bed after surgery. Application of a shielding disk, which is positioned under the target volume, for protecting the normal tissues such as pectoral muscle, lung, and heart is one of the advantages of IOERT in the breast cancer treatment. A common characteristic of these disks is double-layer format; a high atomic number (Z) layer with the ability to absorb the electron beam to prevent penetration to deeper tissues and a Low-Z layer on top of the former to minimize the backscattered electrons from the lower layer. In this study, we have evaluated the misalignment effects of shielding disk on dose distribution inside the target volume and surrounding healthy tissues through EGSnrc MC Simulation. Materials and Methods: LIAC 12 (Sordina IORT Technologies, S.p.A) is a dedicated IOERT machine that can produce electron beam energies of 6, 8, 10, 12MeV. This machine and its dedicated shielding disks which is made from 3 mm steel and 3 mm PMMA were used in this study. Machine head and employed radio-protecting disk were modeled using the BEAMnrc MC code. Some scoring planes were defined at the bottom of the applicator. Before using the phase-space files, the developed MC models were validated through comparing the Monte Carlo calculated PDDs and TDPS with those measured by ionometric dosimetry. EGSnrc C++ class library was used for simulation and calculation of the dose distribution around the shielding disk in some incorrect positions. Backscatter factor (BSF), shielding factor (SF), and percentage of leakage dose (PLD) was calculated as interested shielding parameters. In addition, some extracted parameters form differential DVH such as V100 and S-Index (Uniformity Index) were used to evaluate the dose distribution in the target. Results: The BSFs for all correct and incorrect setups at different nominal energies varied from 1.03 to 1.11, while experimental BSF values ranged from 1.02 to 1.1. By increasing the degree of disk rotation and beam energy, the SF decreases, while the PLD would be increased. By increasing the disk rotation, V100 decrements while the S-index is increased inside the target area. Conclusion: The analysis of uncertainties in shielding disk setup showed that the increment of disk rotation relative to applicator central axis can considerably influence the dose uncertainty inside the target volume and received dose to the organ at risks. Therefore, evaluating the treatment setup after positioning the disk and applicator through intraoperative C-arm imaging can be considered as a mandatory issue for IOERT quality assurance.

Quantification the dosimetric parameters of asymmetric physical wedged-6MV photon beam

Introduction: Physical wedge as a useful tool has been utilized in radiotherapy to modify photon beam shape and intensity such that it distributes dose uniformly in tumor site and reduces hot points. Since during Linac commissioning dosimetric parameters like output factors and lateral dose profiles are measured only for symmetric open and wedged fields, so calculation the parameters for asymmetric wedged fields become necessary. The study aims to achieve output factors and dose profiles for symmetric and asymmetric wedged fields of 6 MV photon beams. Materials and Methods: The Siemens PRIMUS Linac head for 6 MV photon beam was simulated by BEAMnrc and all dose calculations were performed by DOSXYZnrc code. Percentage depth dose (PDD) and profiles for open and wedged (15° and 45°) fields were compared with corresponding measurements. Wedge factors for 10 x 10 cm2 field size as a function of lateral distance from central axis were obtained as well for half beam (negative or positive Y jaws were closed) wedged fields. All mesurments were carried out using 0.125 cm3 Farmer type ionization chamber with DOSE1 electrometer (FC65G, Scanditronix-Wellhofer, Germany) at the depth of 10 cm with source to surface distance (SSD) of 100 cm in 50 cm3 PTW-Blue water phantom and processed by dosimetry software RFAplus (Version 5.2, Scanditronix-Wellhofer, Germany). Results: The calculated doses were in agreement with measured data that confirmed the simulated MC model. The output factors on the central axis of symmetric wedged beams decreased to 0.693 and 0.307 for 15˚ and 45˚ wedges, respectively. The total photon fluence of 15˚ and 45˚ physical wedged fields reduced to 71.6% and 27.7% of fluence for open field, respectively. It was found that the output factor for asymmetric wedged fields is lower than ones from symmetric fields, particularly at field edges. Conclusion: The presences of physical wedge across the beamline decrease the photon fluence and cases beam hardening both for symmetric and asymmetric wedged fields. Lack of scattering photons near the half beam edges in asymmetric wedged field causes a dose fall off in these regions where have potential to overestimate the calculated dose by treatment planning system and consequent cold spots at target volume. Our calculated correction coefficients are recommended to calculate doses by TPS in case of asymmetric wedged fields.

APPLICATION OF EVERYONE IS A TEACHER HERE LEARNING MODEL TO IMPROVE SELF CONFIDENCE STUDENTS

This research is motivated by some students problems about the belief in its ability. This is based on early observation of one-way learning so that students are not used to speaking in front of many people. One of the efforts is to improve self-confidence by applying the learning model of everyone is a teacher here. The objectives to be achieved in this research are: (1) to express the implementation of learning by applying the learning model of everyone is a teacher here to improve student self confidence, (2) To express the improvement of self confidence of students after applying the learning model of everyone is a teacher here. This study is a classroom action research adapted from the Kemmis and Mc model. Taggart. This research was conducted in Grade 4 which amounted to 30 students. The results obtained from the learning process has progressed from cycle I to cycle II. Negative findings found in cycle I amounted to 10, while negative findings in cycle II amounted to two. From the data it is recommended to teachers to use the learning model of everyone is a teacher here to improve student self confidence.

PENERAPAN PENDEKATAN PEMBELAJARAN CONTEXTUAL TEACHING AND LEARNING (CTL) UNTUK MENINGKATKAN HASIL BELAJAR SISWA KELAS VIII C PADA MATERI LUAS DAN KELILING LINGKARAN DI MTS BIROBULI

To improve students' learning outcomes on the broad and circle of the circle, the researcher applied the learning using Contextual Teaching And Learning (CTL) approach. Researchers conduct classroom action research using a qualitative approach. The design of this study refers to the Kemmis and MC models. Taggrt which consists of four components, namely (1) Planning (Planning), (2) Implementation of action (Action), (3) Observation, and (4) reflection. Based on the research result, it was found that the students of grade VIII C MTS Birobuli in cycle I, from 27 students who completed the final test of action there were 13 complete students, so that the percentage of learning completeness equal to 48%, and in cycle II, from 27 students who took the final test action there are 22 complete students with percentage mastery 81%. Based on these results, it can be concluded that the forwarding of learning model Contextual Teaching And Learning (CTL) can improve the learning outcomes of students of class VIII C MTS Birobuli on the circumference material and the area of the circle.

OA239] Monte Carlo as quality control tool of machine performance and treatment planning system, is it a luxury or a necessity?

Purpose During last decades many radiotherapy machines, treatment planning systems (TPS) and complicated treatment techniques (VMAT, IMRT, SBRT) have been developed. Fast dose calculation algorithms are used for radiotherapy, applying many approximations during dose calculation to minimize calculation time. The main objective of this presentation is to present how to implement Monte Carlo in clinical daily quality control of TPS and machine performance. Methods EGSnrc ⧹ BEAMnrc were used to create a model of the Agility (Elekta) by using the data provided by the manufacturer. Validation of the MC model was done using the methodology of Pena[1]. Comparison of standard treatment plans between MC treatment planning system and measurements was necessary to verify moving parts of the machine. Converting RTplan DICOM files to MC input files and converting MC dose matrix file to a DICOM file were done using the Moderato platform [2]. Impacts of variance reduction techniques, voxel size and simulating volume were well investigated to minimize calculation time. Homemade MATLAB code was used to extract the data from machine log files which was used as input for MC simulation. Results Validation of MC model was within 2% when comparing to measurement for all PDDs, profiles and output factors of different fields sizes. Good agreement was obtained between TPS algorithm and MC for most of the cases, but small differences were found for small lung lesions, as MC and TPS do not use same cut off energy of secondary electrons. TPS and MC plans using machine log files have a good agreement for all patients. 30 min as max of calculation time and 1% uncertainty for all planning treatment volumes (PTVs) are respected for all patients. The system is currently being extended to use it with other external radiotherapy machines like Clinac® (Varian) and Gamma Knife (Elekta) for double calculation and delivered dose verification. Conclusions Monte Carlo has been used to validate TPS plans as well as performance of the external radiotherapy machine (Agility (Elekta)). Beside to measurements, MC as independent quality control tool is important for complicated treatment techniques.

Shielding disk position in intra-operative electron radiotherapy (IOERT): A Monte Carlo study

PurposeIn IOERT breast treatments, a shielding disk is frequently used to protect the underlying healthy structures. The disk is usually composed of two materials, a low-Z material intended to be oriented towards the beam and a high-Z material. As tissues are repositioned around the shield before treatment, the disk is no longer visible and its correct alignment with respect to the beam is guaranteed. This paper studies the dosimetric characteristics of four possible clinical positioning scenarios of the shielding disk. A new alignment method for the shielding disk in the beam is introduced. Finally, it suggests a new design for the shielding disk. MethodsAs the first step, the IOERT machine “Mobetron 1000” was modeled by using Monte Carlo simulation, tuning the MC model until an excellent match with the measured PDDs and profiles was achieved. Four possible shielding disk positioning scenarios were considered, determining the dosimetric impact. Furthermore, in our center, to prevent beam misalignment, we have developed a shielding disk equipped with guiding rods. Having ascertained a correct alignment between the disk and the beam, we can propose a new internal design of the shielding disk that can improve the dose distribution with a better coverage of the treated area. ResultsAll MC simulations were performed with a 12 MeV beam, the maximum energy of Mobetron 1000 and a 5.5 cm diameter flat tip applicator, this applicator being the most clinically used. The simulations were compared with measurements performed in a water phantom and showed good results within 2.2% of root mean square difference (RMSD). The misplacement positions of the shielding disk have dosimetric impacts in the treatment volume and a small translation could have a significant influence on healthy tissues. The D-scenario is the worst which could happens when the shielding disk is flipped upside down, giving up to 144% dose instead of 90% at the surface of the Pb/Al shielding disk. A new shielding design used, together with our alignment tool, is able to give a more homogeneous dose in the target area. ConclusionsThe accuracy of shielding disk position can still be problematic in IOERT dosimetry. Any method that can ascertain the good alignment between the shielding disk and the beam is beneficial for the dose distribution and is a prerequisite for an optimized shield internal design that could improve the coverage of the treated area and the protection of healthy tissues.

IMPROVED INTERPERSONAL INTELLIGENCE MODEL STUDENTS THROUGH COOPERATIVE LEARNING (TYPE two stay two stray) IN LEARNING IPS (Classroom Action Research in Class VIII C SMP Negeri 45 Bandung)

Abstract-This research is supported by low interpersonal intelligence of learners on IPS learning in class VIII C SMP Negeri 45 Bandung. This can be seen from the still low empathy, prosocial, low self-awareness as a member of the group, social ethics of learners, problem-solving skills and effective communication skills of learners. Seeing the problem, the researcher chose Cooperative Learning Model Type Two Stay Two Stray (TSTS) as a solution to improve students' interpersonal intelligence. The purpose of this study is to describe the planning, implementation, obstacles and solutions and increase interpersonal intelligence. The type of research used is Class Action Research (PTK) Kemmis and Mc model. Taggart which consists of four stages. Stages of planning in this study include determining SK / KD and teaching materials, preparing RPP, Student Worksheet and create research instruments according to the needs of researchers. This research was conducted in three cycles and obtained the result of improvement of students' interpersonal intelligence in IPS learning. Increased interpersonal intelligence of learners is characterized by an increase that occurs in every aspect of the assessment of interpersonal intelligence. This proves cooperative learning model type two stay two stray (TSTS) can improve students' interpersonal intelligence.Keywords: Interpersonal Intelligence, Cooperative Learning Model type Two Stay Two Stray (TSTS).

Root-Based Nonlinear Companding Technique for Reducing PAPR of Precoded OFDM Signals

Orthogonal frequency division multiplexing (OFDM) signals are characteristically independent and identically distributed Gaussian random variables that follow Rayleigh distribution. The signals also exhibit high peak-to-average power ratio (PAPR) problem due to the infinitesimal amplitude component distributed above the mean of the Rayleigh distribution plot. Since the amplitudes are nonlinearly and non-monotonically increasing, applying roots to the amplitude distribution is shown in this paper to change the probability density function (PDF) and thus reduces the PAPR. We exemplify these by imposing this constraint on standard $\mu $ -law companding (MC) technique in reducing PAPR of OFDM signals, which is known to expand the amplitudes of low power signals only without impacting the higher amplitude signals. This limits the PAPR reduction performance of the MC scheme. Since companding involves simultaneously compressing/expanding high/low amplitude OFDM signals, respectively, in this paper, we refer to the new method as a root-based MC (RMC) scheme that simultaneously expands and compresses OFDM signal amplitudes unlike MC. In addition, we express a second transform independent of the MC model. The results of the two proposed schemes outperform four other widely used companding techniques [MC, log-based modified (LMC), hyperbolic arc-sine companding (HASC) and exponential companding (EC)]. Besides these, we precode the OFDM signals using discrete Hartley transform (DHT) in order to further reduce the PAPR limits achieved by RMC by distorting the phase. While preserving the BER, DHT-precoded RMC outperforms all the four other companding schemes (MC, EC, HASC, LMC) in terms of PAPR.

News on mean pion multiplicity from NA61/SHINE

NA61/SHINE is a large acceptance fixed target experiment at the CERN SPS which studies final hadronic states in interactions between various particles and nuclei [1]. The main topic of this contribution are preliminary results for mean negatively charged pion multiplicities 〈π−〉 from central Ar+Sc and Be+Be collisions. The data were taken recently by the NA61/SHINE collaboration for a wide range of beam momenta. Measured rapidity distributions [see formula in PDF] were extrapolated to unmeasured regions to obtain total multiplicities 〈π−〉 A new scheme to calculate the mean number of wounded nucleons 〈W〉 utilizing the EPOS MC model is described. Using data from other experiments, a comparison of [see formula in PDF]for different collisions and beam momenta is discussed.