Optimization of transport protocols with path-length constraints in complex networks

We propose a protocol optimization technique that is applicable to both weighted or unweighted graphs. Our aim is to explore by how much a small variation around the Shortest Path or Optimal Path protocols can enhance protocol performance. Such an optimization strategy can be necessary because even though some protocols can achieve very high traffic tolerance levels, this is commonly done by enlarging the path-lengths, which may jeopardize scalability. We use ideas borrowed from Extremal Optimization to guide our algorithm, which proves to be an effective technique. Our method exploits the degeneracy of the paths or their close-weight alternatives, which significantly improves the scalability of the protocols in comparison to Shortest Paths or Optimal Paths protocols, keeping at the same time almost intact the length or weight of the paths. This characteristic ensures that the optimized routing protocols are composed of paths that are quick to traverse, avoiding negative effects in data communication due to path-length increases that can become specially relevant when information losses are present.Comment: 8 pages, 8 figure

Faktor-Faktor yang Mempengaruhi Produksi Usaha Tani Sayur Sawi di Kelurahan Bensone Kecamatan Kota Kefamenanu Kabupaten Timor Tengah Utara

Penelitian ini bertujuan untuk mengetahui gambaran umum USAhatani sayur sawi dan juga faktor – faktor yang mempengaruhi produksi USAhatani sayur sawi. Metode pengambilan sampel adalah simple random sampling, dengan jumlah petani sebanyak 50 sampel. Analisis yang digunakan adalah analisis regresi linier berganda dalam bentuk logaritma dengan fungsi produksi Cobb-Douglas. Hasil uji F menunjukkan bahwa secara keseluruhan variabel bebas secara bersama-sama dapat menunjukkan pengaruhnya terhadap faktor produksi sawi dengan nilai Fhitung sebesar (712.476) ˃ nilai Ftabel (2.32), sedangkan hasl uji T menunjukan bahwa faktor-faktor produksi yang berpengaruh secara nyata terhadap produksi sayur sawi di Kelurahan Bansone adalah faktor luas lahan dengan nilai thitung luas lahan (4.090) > ttabel (1,684), faktor benih dengan nilai thitung benih(1.974) ˃ ttabel (1.684), faktor modal dengan nilai thitung modal (2.479) ˃ ttabel (1.684), faktor tenaga kerja dengan nilai thitung tenaga kerja (2.785) > ttabel(1.684) berpengaruh secara nyata terhadap produksi USAhatani sayur sawi sedangkan faktor pupuk dengan nilai thitung pupuk (0.164) ˂ ttabel (1.684), faktor pengalaman degan nilai thitung pengalaman (1.117) ˂ ttabel (1.684) dan faktor pendidikan formal dengan nilai thitung pendidikan (0.321) ˂ ttabel (1.684) tidak berpengaruh secara nyata terhadap produksi USAhatani sayur sawi. ©2016 dipublikasikan oleh Agrimor

Van Kampen's expansion approach in an opinion formation model

We analyze a simple opinion formation model consisting of two parties, A and B, and a group I, of undecided agents. We assume that the supporters of parties A and B do not interact among them, but only interact through the group I, and that there is a nonzero probability of a spontaneous change of opinion (A->I, B->I). From the master equation, and via van Kampen's Omega-expansion approach, we have obtained the "macroscopic" evolution equation, as well as the Fokker-Planck equation governing the fluctuations around the deterministic behavior. Within the same approach, we have also obtained information about the typical relaxation behavior of small perturbations.Comment: 17 pages, 6 figures, submited to Europ.Phys.J.

Reiteraciones: ritmo y diseminación en Génesis 1,1-2,4a

 PRELIMINARES. I. LA SECCIÓN CENTRAL. 1. La disposición rítmica de Génesis 1,3-31. 1.1. Ritmo. 1.2. Diseminación. 2. Una hipótesis sobre el procedimiento de construcción de Génesis 1,3-31. 3. El sentido de la presencia de los elementos rítmicos y de los diseminados. 3.1. La presencia de los días. 3.2. La presencia de las acciones. 3.2.1. Las seis acciones centrales. 3.2.2. Las dos acciones marginales. 3.3. La estructura de cada acción creadora. 3.3.1. «Y dijo Dios». 3.3.2. «Y fue así». 3.3.3. Las operaciones con las que Dios crea. 3.3.4. «Y llamó». «Y vio». 4. Progresión temática. II. LAS SECCIONES MARGINALES. CONCLUSIONES

Discretization-related issues in the KPZ equation: Consistency, Galilean-invariance violation, and fluctuation--dissipation relation

In order to perform numerical simulations of the KPZ equation, in any dimensionality, a spatial discretization scheme must be prescribed. The known fact that the KPZ equation can be obtained as a result of a Hopf--Cole transformation applied to a diffusion equation (with \emph{multiplicative} noise) is shown here to strongly restrict the arbitrariness in the choice of spatial discretization schemes. On one hand, the discretization prescriptions for the Laplacian and the nonlinear (KPZ) term cannot be independently chosen. On the other hand, since the discretization is an operation performed on \emph{space} and the Hopf--Cole transformation is \emph{local} both in space and time, the former should be the same regardless of the field to which it is applied. It is shown that whereas some discretization schemes pass both consistency tests, known examples in the literature do not. The requirement of consistency for the discretization of Lyapunov functionals is argued to be a natural and safe starting point in choosing spatial discretization schemes. We also analyze the relation between real-space and pseudo-spectral discrete representations. In addition we discuss the relevance of the Galilean invariance violation in these consistent discretization schemes, and the alleged conflict of standard discretization with the fluctuation--dissipation theorem, peculiar of 1D.Comment: RevTex, 23pgs, 2 figures, submitted to Phys. Rev.

Phase transition in the Sznajd model with independence

We propose a model of opinion dynamics which describes two major types of social influence -- conformity and independence. Conformity in our model is described by the so called outflow dynamics (known as Sznajd model). According to sociologists' suggestions, we introduce also a second type of social influence, known in social psychology as independence. Various social experiments have shown that the level of conformity depends on the society. We introduce this level as a parameter of the model and show that there is a continuous phase transition between conformity and independence