Rm DR Research Articles

Penerapan Metode Monte Carlo pada Simulasi Antrian Poliklinik RSUD DR. RM. Djoelham

Long queues at the polyclinic of RSUD RM DR Djoelham Binjai often cause inconvenience to patients and reduce service efficiency. This study aims to analyze the queuing system at the hospital's polyclinic using the Monte Carlo method, which is able to model uncertainty in patient arrivals and service times. With this method, it is expected that a more accurate picture of patient waiting time and queue performance can be obtained so that improvement measures can be identified. The data used in this simulation includes the number of patients who come and the service time in the polyclinic. Monte Carlo simulations are carried out to predict various queuing scenarios based on variations that occur in patient arrivals and service duration. The simulation results provide information related to the estimated average waiting time of patients, and the level of queue density. This study shows that the application of the Monte Carlo method is effective in providing a more measurable solution to minimize waiting time and improve service quality at the polyclinic of RM DR Djoelham Binjai Hospital. These results are expected to be a reference for hospital management in making strategic decisions related to the optimization of health services. With the average waiting time for patients in the queue is 10.59 minutes while the average patient time is 25.34 minutes.

A Harder–Narasimhan stratification of the -Grassmannian

We establish a Harder–Narasimhan formalism for modifications of $G$-bundles on the Fargues–Fontaine curve. The semi-stable stratum of the associated stratification of the ${B^+_{{\rm dR}}}$-Grassmannian coincides with the variant of the weakly admissible locus defined by Viehmann, and its classical points agree with those of the basic Newton stratum. When restricted to minuscule affine Schubert cells, the stratification corresponds to the Harder–Narasimhan stratification of Dat, Orlik and Rapoport. We also study basic geometric properties of the strata, and the relation to the Hodge–Newton decomposition.

Free–free absorption in hot relativistic flows: application to fast radio bursts

ABSTRACT Magnetic flares create hot relativistic shocks outside the light cylinder radius of a magnetized star. Radio emission produced in such a shock or at a radius smaller than the shock undergoes free–free absorption while passing through the shocked medium. In this work, we demonstrate that this free–free absorption can lead to a negative drift in the frequency-time spectra. Whether it is related to the downward drift pattern observed in fast radio bursts (FRBs) is unclear. However, if the FRB down-drifting is due to this mechanism then it will be pronounced in those shocks that have isotropic kinetic energies $ \gtrsim 10^{44}$ erg. In this model, for an internal shock with a Lorentz factor ∼100, the normalized drift rate $|{\rm DR_{\rm obs}}|/\nu _{\rm mean}$ is ∼10−2 per ms, where νmean is the central frequency of the radio pulses. The corresponding radius of the shocked shell is, therefore, in the range of 1010 cm and 1011 cm. This implies that, for an outflow consisting of hydrogen ion, the upper limit on the mass of the relativistic shocks is a few × 10−10 M⊙, which is considerably low compared to that ejected from SGR 1806-20 during the 2004 outburst.

Newton polytopes and algebraic hypergeometric series

Let $X$ be the family of hypersurfaces in the odd-dimensional torus ${\mathbb T}^{2n+1}$ defined by a Laurent polynomial $f$ with fixed exponents and variable coefficients. We show that if $n\Delta$, the dilation of the Newton polytope $\Delta$ of $f$ by the factor $n$, contains no interior lattice points, then the Picard-Fuchs equation of $W_{2n}H^{2n}_{\rm DR}(X)$ has a full set of algebraic solutions (where $W_\bullet$ denotes the weight filtration on de Rham cohomology). We also describe a procedure for finding solutions of these Picard-Fuchs equations.

Rigid connections and $F$-isocrystals

An irreducible integrable connection $(E,\nabla)$ on a smooth projective complex variety $X$ is called rigid if it gives rise to an isolated point of the corresponding moduli space $\mathcal{M}_{\rm dR}(X)$. According to Simpson’s motivicity conjecture, irreducible rigid flat connections are of geometric origin, that is, arise as subquotients of a Gauss–Manin connection of a family of smooth projective varieties defined on an open dense subvariety of $X$. In this article we study mod-$p$ reductions of irreducible rigid connections and establish results which confirm Simpson’s prediction. In particular, for large $p$, we prove that $p$-curvatures of mod-$p$ reductions of irreducible rigid flat connections are nilpotent, and building on this result, we construct an $F$-isocrystalline realization for irreducible rigid flat connections. More precisely, we prove that there exist smooth models $X_R$ and $(E_R,\nabla_R)$ of $X$ and $(E,\nabla)$, over a finite-type ring $R$, such that for every Witt ring $W(k)$ of a finite field $k$ and every homomorphism $R \to W(k)$, the $p$-adic completion of the base change $(\widehat{E}_{W(k)},\widehat{\nabla}_{W(k)})$ on $\widehat{X}_{W(k)}$ represents an $F$-isocrystal. Subsequently, we show that irreducible rigid flat connections with vanishing $p$-curvatures are unitary. This allows us to prove new cases of the Grothendieck–Katz $p$-curvature conjecture. We also prove the existence of a complete companion correspondence for $F$-isocrystals stemming from irreducible cohomologically rigid connections.

Trees with Double Roman Domination Number Twice the Domination Number Plus Two

A double Roman dominating function (DRDF) on a graph $$G=(V,E)$$ is a function $$f:V(G)\rightarrow \{0,1,2,3\}$$ such that (i) every vertex v with $$f(v)=0$$ is adjacent to at least two vertices assigned a 2 or to at least one vertex assigned a 3, (ii) every vertex v with $$f(v)=1$$ is adjacent to at least one vertex w with $$f(w)\ge 2.$$ The weight of a DRDF is the sum of its function values over all vertices. The double Roman domination number $$\gamma _{\rm dR}(G)$$ equals the minimum weight of a double Roman dominating function on G. Beeler, Haynes and Hedetniemi showed that for every non-trivial tree T, $$\gamma _{\rm dR}(T)\ge 2\gamma (T)+1,$$ where $$\gamma (T)$$ is the domination number of T. A characterization of extremal trees attaining this bound was given by three of us. In this paper, we characterize all trees T with $$\gamma _{\rm dR}(T)=2\gamma (T)+2$$ .

New observational limits on dark radiation in braneworld cosmology

A dark radiation term arises as a correction to the energy momentum tensor in the simplest five-dimensional RS-II brane-world cosmology. In this paper we revisit the constraints on dark radiation based upon the newest results for light-element nuclear reaction rates, observed light-element abundances and the power spectrum of the Cosmic Microwave Background (CMB). Adding dark radiation during big bang nucleosynthesis alters the Friedmann expansion rate causing the nuclear reactions to freeze out at a different temperature. This changes the final light element abundances at the end of BBN. Its influence on the CMB is to change the effective expansion rate at the surface of last scattering. We find that our adopted BBN constraints reduce the allowed range for dark radiation to between $-12.1\%$ and $+6.2\%$ of the ambient background energy density. Combining this result with fits to the CMB power spectrum, the range decreases to $-6.0\%$ to $+6.2\%$. Thus, we find, that the ratio of dark radiation to the background total relativistic mass energy density $\rho_{\rm DR}/\rho$ is consistent with zero although in the BBN analysis there could be a slight preference for a negative contribution. However, the BBN constraint depends strongly upon the adopted primordial helium abundance.

Theoretical uncertainty of the supersymmetric dark matter relic density from scheme and scale variations

For particle physics observables at colliders such as the LHC at CERN, it has been common practice for many decades to estimate the theoretical uncertainty by studying the variations of the predicted cross sections with a priori unpredictable scales. In astroparticle physics, this has so far not been possible, since most of the observables were calculated at Born level only, so that the renormalization scheme and scale dependence could not be studied in a meaningful way. In this paper, we present the first quantitative study of the theoretical uncertainty of the neutralino dark matter relic density from scheme and scale variations. We first explain in detail how the renormalization scale enters the tree-level calculations through coupling constants, masses and mixing angles. We then demonstrate a reduction of the renormalization scale dependence through one-loop SUSY-QCD corrections in many different dark matter annihilation channels and enhanced perturbative stability of a mixed on-shell/$\bar{\rm DR}$ renormalization scheme over a pure $\bar{\rm DR}$ scheme in the top-quark sector. In the stop-stop annihilation channel, the Sommerfeld enhancement and its scale dependence are shown to be of particular importance. Finally, the impact of our higher-order SUSY-QCD corrections and their scale uncertainties are studied in three typical scenarios of the phenomenological Minimal Supersymmetric Standard Model with eleven parameters (pMSSM-11). We find that the theoretical uncertainty is reduced in many cases and can become comparable to the size of the experimental one in some scenarios.

Study of the renormalization-group evolution ofN=1supersymmetric gauge theories using Padé approximants

We study asymptotically free SU($N_c$) gauge theories with ${\cal N}=1$ supersymmetry, including the purely gluonic theory and theories with $N_f$ copies of a pair of massless chiral superfields in the respective representations $R$ and $\bar R$ of SU($N_c$). The cases in which $R$ is the fundamental representation and the symmetric and antisymmetric rank-2 tensor representation are considered. We calculate Pad\'e approximants to the beta functions for these theories in the $\overline{\rm DR}$ scheme up to four-loop order for the gluonic theory and up to three-loop order for the theories with matter superfields and compare results for IR zeros and poles with results from the NSVZ beta function. Our calculations provide a quantitative measure, for these theories, of how well finite-order perturbative results calculated in one scheme reproduce properties of a known beta function calculated in a different scheme.

Tensorial Independent Component Analysis-Based Feature Extraction for Polarimetric SAR Data Classification

For polarimetric synthetic aperture radar (PolSAR) data, various polarimetric signatures can be obtained by target decomposition techniques, which are of great help for characterizing the land cover. It is straightforward to combine these polarimetric features together and formulate them as a third-order polarimetric feature tensor. However, how to make full use of the abundant information provided by these polarimetric features remains a challenge. A feasible solution is applying feature extraction (FE) techniques on the high-dimensional polarimetric manifold to obtain a lower dimensional intrinsic feature set. Common FE methods, such as principal component analysis (PCA), independent component analysis (ICA), etc., use matrix linear algebra and require rearranging the original tensor into a matrix. This leads to the loss of the spatial information of the PolSAR data. In this paper, to jointly take advantage of the spatial and feature information, a novel FE scheme incorporating ICA with the tensor decomposition techniques is proposed. After applying the proposed FE method on the third-order polarimetric feature tensor, each PolSAR image pixel is represented by a low-dimensional intrinsic feature vector. Furthermore, these feature vectors are fed to the $k$ -nearest neighbor (KNN) classifier and support-vector-machine classifier for supervised classification. Simulated data, together with two measured data sets, i.e., Flevoland of Airborne Synthetic Aperture Radar (AIRSAR) and Quebec City of Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), are utilized to evaluate the performance of the proposed method. For comparison purpose, several classical and advanced FE methods, such as PCA, ICA, Laplacian eigenmaps, and $\hbox{LRTA}_{\rm dr}-(K_{1},K_{2},p)$ , are also applied. The experimental results demonstrate the superiority of the proposed FE method in three folds: 1) The extracted features by the proposed method are more discriminative, characterized by the high separability in the scatterplots; 2) the classification accuracy is improved as much as approximately 7% compared with the complex Wishart classifier; and 3) the proposed method is computational efficient and has fast convergence.

One-loop SQCD corrections to the decay of top squarks to charm and neutralino in the generic MSSM

In this article we calculate the 1-loop supersymmetric QCD (SQCD) corrections to the decay $\tilde u_1\to c \tilde\chi^0_1$ in the MSSM with generic flavour structure. This decay mode is phenomenologically important if the mass difference between the lightest squark $\tilde u_1$ (which is assumed to be mainly stop-like) and the neutralino LSP $\tilde \chi^0_1$ is smaller than the top mass. In such a scenario $\tilde u_1\to t \tilde\chi^0_1$ is kinematically not allowed and searches for $\tilde u_1\to W b \tilde\chi^0_1$ and $\tilde u_1\to c \tilde\chi^0_1$ are performed. A large decay rate for $\tilde u_1\to c \tilde\chi^0_1$ can weaken the LHC bounds from $\tilde u_1\to W b \chi^0_1$ which are usually obtained under the assumption ${\rm Br}[\tilde u_1\to W b \chi^0_1]=100\%$. We find the SQCD corrections enhance $\Gamma[\tilde u_1\to c \tilde\chi^0_1]$ by approximately 10\% if the flavour-violation originates from bilinear terms. If flavour-violation originates from trilinear terms, the effect can be $\pm 50\%$ or more, depending on the sign of $A^t$. We note that connecting a theory of SUSY breaking to LHC observables, the shift from the $\overline{\rm DR}$ to the on-shell mass is numerically very important for light stop decays.

Zenith/Nadir Pointing mm-Wave Radars: Linear or Circular Polarization?

We consider zenith/nadir pointing atmospheric radars and explore the effects of different dual-polarization architectures on the retrieved variables: reflectivity, depolarization ratio, cross-polar coherence, and degree of polarization. Under the assumption of azimuthal symmetry, when the linear depolarization ratio (LDR) and circular depolarization ratio (CDR) modes are compared, it is found that for most atmospheric scatterers reflectivity is comparable, whereas the depolarization ratio dynamic range is maximized at CDR mode by at least 3 dB. In the presence of anisotropic (aligned) scatterers, that is, when azimuthal symmetry is broken, polarimetric variables at CDR mode do have the desirable property of rotational invariance and, further, the dynamic range of CDR can be significantly larger than the dynamic range of LDR. The physical meaning of the cross-polar coherence is revisited in terms of scattering symmetries, that is, departure from reflection symmetry for the LDR mode and departure from rotation symmetry for the CDR mode. The Simultaneous Transmission and Simultaneous Reception mode (STSR mode or hybrid mode or <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$Z_{\rm DR}$</tex></formula> mode) is also theoretically analyzed for the case of zenith/nadir pointing radars and, under the assumption of azimuthal symmetry, relations are given to compare measurements obtained at hybrid mode with measurements obtained from orthogonal (LDR and CDR) modes.

Note on Large Subsets of Binary Vectors with Similar Distances

We consider vectors from $\{0,1\}^n$. The weight of such a vector $v$ is the sum of the coordinates of $v$. The distance ratio of a set $L$ of vectors is ${\rm dr}(L):=\max \{\rho(x,y):\ x,y \in L\}/ \min \{\rho(x,y):\ x,y \in L,\ x\neq y\},$ where $\rho(x,y)$ is the Hamming distance between $x$ and $y$. We prove that (a) for every constant $\lambda>1$ there are no positive constants $\alpha$ and $C$ such that every set $K$ of at least $\lambda^p$ vectors with weight $p$ contains a subset $K'$ with $|K'|\ge |K|^{\alpha}$ and ${\rm dr}(K')\le C$; and (b) for a set $K$ of vectors with weight $p$, and a constant $C>2$, there exists $K'\subseteq K$ such that ${\rm dr}(K')\le C$ and $|K'| \ge |K|^\alpha$, where $\alpha = 1/ \lceil \log(p/2)/\log(C/2) \rceil$.

Microflow-based control of near-wall fluctuations for large viscous drag reduction

The stabilizing effect of microgroove surface morphology on viscous drag reduction was studied experimentally in the inlet region of a plane channel flow. The stabilization is thought to be due to the ability of a microgrooved surface pattern to suppress the velocity fluctuations in the spanwise direction on a restricted portion of the wetted surface, which prevents vorticity development at the wall and consequently across the entire flow field. This smart microflow control strategy, which works successfully only under very particular circumstances, was implemented in a microgroove-modified channel flow in which the front part has a microgrooved surface topology. The results of pressure drop measurements indicate that microgrooved surfaces can effectively stabilize laminar boundary layer development, leading to a significant reduction in the viscous drag. In the rear flat part of the microgroove-modified channel test section, a maximum drag reduction of \({\rm DR\simeq 35\%}\) was measured. This corresponds to an overall drag reduction of \({\rm DR\simeq 16\%}\) at a length Reynolds number of \(Re_x\simeq 10^6. \) The drag reduction effect persisted in a narrow range of flow velocities and for the reported experimental conditions corresponds to microgroove dimensions between 1.5 and 2.5 viscous length-scales.

Effect of Hot Band Grain Size on the Anisotropy of Warm Rolled Low Carbon Steels

In warm rolled steels, the intensity of the &lt;111&gt;//ND annealing texture, which favours formability, has been related to the formation of shear bands during rolling. Coarse hot band grain sizes (HBGS’s) facilitate flow localization, the mechanism associated with the formation of shear bands.In this work, the effect of grain size after hot rolling was studied in a low carbon steel containing small additions of Cr and Mn. The formation of shear bands and their subsequent influence on the normal anisotropy rm and planar anisotropy Dr in the annealed steels were of particular interest. Two HBGS’s (18 and 30mm) were employed and the specimens were warm rolled to reductions of 65 and 80% at various temperatures between 640 and 700°C. The results show that the frequency of shear banding is slightly lower for the smaller grain size. The normal anisotropy was not affected by the HBGS; by contrast, much lower Dr values were associated with the finer grained steel.

One-loop calculations for SUSY processes

Strategy and results for complete one-loop computations in the Minimal Supersymmetric Standard Model are reviewed, with applications to the calculation of SUSY mass spectra and SUSY-particle processes. Determination of renormalization constants and counterterms are described in the on-shell renormalization scheme, and a translation between $\bar{\rm DR}$ and on-shell parameters is given. As an example, cross sections for chargino and neutralino pair production in $e^+e^-$ annihilation are presented, complete at the one-loop level.

Local ν-Euler Derivations and Deligne's¶Characteristic Class of Fedosov Star Products¶and Star Products of Special Type

In this paper we explicitly construct local ν-Euler derivations $\mathsf E_\alpha = \nu \partial_\nu + \Lie{\xi_\alpha} + \mathsf D_\alpha$ , where the ξα are local, conformally symplectic vector fields and the $\mathsf D_\alpha$ are formal series of locally defined differential operators, for Fedosov star products on a symplectic manifold (M,ω) by means of which we are able to compute Deligne's characteristic class of these star products. We show that this class is given by $\frac{1}{\nu}[\omega]+\frac{1}{\nu} [\Omega]$ , where $\Omega \in \nu Z^2_{{\rm dR}}(M)[[\nu]]$ is a formal series of closed two-forms on M the cohomology class of which coincides with the one introduced by Fedosov to classify his star products. Moreover, we consider star products that have additional algebraic structures and compute the effect of these structures on the corresponding characteristic classes of these star products. Specifying the constituents of Fedosov's construction we obtain star products with these special properties. Finally, we investigate equivalence transformations between such special star products and prove existence of equivalence transformations being compatible with the considered algebraic structures. Dedicated to the memory of Moshe Flato