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Mahasiswa dalam Pembangunan Politik : Idealisme Versus Realisme Politik
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| Pengarang | : | Syam, Firdaus |
| Nama Majalah/Jurnal | : | Ilmu dan Budaya |
| Volume / Edisi | : | VIII-4, JANUARI (No. 4) |
| Halaman | : | 304-314 |
| Abstrak | : | - |
Unchained Catenaries
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | The College Mathematics Journal |
| Volume / Edisi | : | 56 (No. 1) |
| Halaman | : | 15-24 |
| Abstrak | : | Catenaries are the curves formed by a uniform chain or cable suspended from two ends. They are seen in the natural world in structures such as spider webs, and they also occur in engineered structures, including bridges and overhead power lines. Catenaries and catenary arches are also employed in architecture for their beauty and strength. In this article, we look at catenaries where a chain is fixed at one endpoint but free to move over the other. Such catenaries will either be supported by the weight of the tail end of the chain and hence be “stable,” or else unwind off the free end and adopt the configuration of a vertically hanging chain. We develop two models, which are analyzed to determine the conditions under which a particular system will be either stable or unstable and determine the widest span for which a stable catenary exists. The predictions made here may be explored experimentally with relatively inexpensive apparatus. The models presented also invite extensions, such as more general free point locations and the addition of friction, which could dissipate the system energy. |
Konsep Pemisahan Negara-Gereja : Hubungan Partai Katolik dan Mawi
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Ilmu dan Budaya |
| Volume / Edisi | : | VIII-4, JANUARI (No. 4) |
| Halaman | : | 299-303 |
| Abstrak | : | - |
Recursively Generated Spirals
| Pengarang | : | Vincent J. Matsko |
| Nama Majalah/Jurnal | : | The College Mathematics Journal |
| Volume / Edisi | : | 56 (No. 1) |
| Halaman | : | 4-14 |
| Abstrak | : | When the angles are changed in the usual algorithm to generate the Koch curve, a wide variety of images may be produced, some of which possess rotational symmetry. One family of such images consists of simple spiral-like images. While there are only two segments in each spiral arm, the number of segments that must be drawn to render a complete image of the spiral grows exponentially with the number of arms in the spiral. |
Radial Amplitude Equations for Fully Localized Planar Patterns
| Pengarang | : | Dan J. Hill, David J. Lloyd |
| Nama Majalah/Jurnal | : | Siam Journal On Applied Mathematics |
| Volume / Edisi | : | 84 (No. 6) |
| Halaman | : | 2590-2611 |
| Abstrak | : | Isolated patches of spatially oscillating pattern have been found to emerge near a pattern-forming instability in a wide variety of experiments and mathematical models. However, there is currently no mathematical theory to explain this emergence or characterize the structure of these patches. We provide a method for formally deriving radial amplitude equations to planar patterns via nonautonomous multiple-scale analysis and convolutional sums of products of Bessel functions. Our novel approach introduces nonautonomous differential operators, which allow for the systematic manipulation of Bessel functions, as well as previously unseen identities involving infinite sums of Bessel functions. Solutions of the amplitude equations describe fully localized patterns with nontrivial angular dependence, where localization occurs in a purely radial direction. Amplitude equations are derived for multiple examples of patterns with dihedral symmetry, including fully localized hexagons and quasipatterns with twelve-fold rotational symmetry. In particular, we show how to apply the asymptotic method to the Swift–Hohenberg equation and general reaction-diffusion systems. |
Dynamics of a Reaction-Diffusion SIS Epidemic Model with a Control Zone
| Pengarang | : | |
| Nama Majalah/Jurnal | : | Siam Journal On Applied Mathematics |
| Volume / Edisi | : | 84 (No. 6) |
| Halaman | : | 2569-2589 |
| Abstrak | : | In this paper, we investigate a susceptible-infected-susceptible (SIS) reaction-diffusion model with a control zone where new infections do not occur. We introduce a basic reproduction number ?0 and establish threshold-type results on the global dynamics in terms of ?0. In particular, we design the optimal control zone by investigating the influence of the starting point and length of the control zone in a one-dimensional bounded habitat on disease transmission. We also study the asymptotic distribution of the endemic steady state when the diffusion rates of the population are sufficiently small or large. Our analytical results show that the introduction of control zones tends to suppress the persistence of the disease to some extent and that the restriction of the movement of a population yields to the extinction of the disease at least in low-risk areas. |
Pembangunan dan Perubahan Sosial di Minahasa Sebuah Pengamatan Awal dari Luar
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Ilmu dan Budaya |
| Volume / Edisi | : | VIII-4, JANUARI (No. 4) |
| Halaman | : | 291-298 |
| Abstrak | : | - |
Beberapa Segi dari Sosial Budaya Kaitannya dengan Kurang Kalori Protein
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Ilmu dan Budaya |
| Volume / Edisi | : | VIII-4, JANUARI (No. 4) |
| Halaman | : | 276-290 |
| Abstrak | : | - |
Evolution of Derivative Singularities in Hyperbolic Quasilinear Systems of Conservation Laws
| Pengarang | : | Russell Arnold, Roberto Camassa, Gregorio Falqui, Giovanni Ortenzi, Marco Pedroni |
| Nama Majalah/Jurnal | : | Siam Journal On Applied Mathematics |
| Volume / Edisi | : | 84 (No. 6) |
| Halaman | : | 2545-2568 |
| Abstrak | : | Motivated by problems arising in the piecewise construction of physically relevant solutions to models of shallow water fluid flows, we study the initial value problem for quasilinear hyperbolic systems of conservation laws in 1+1 dimensions when the initial data are continuous with “corners,” i.e., derivative discontinuities. While it is well known that generically such discontinuities propagate along characteristics, under which conditions the initial corner points may fission into several ones, and which characteristics they end up following during their time evolution, seems to be less understood; this study aims at filling this knowledge gap. To this end, a distributional approach to moving singularities is constructed, and criteria for selecting the corner-propagating characteristics are identified. The extreme case of initial corners occurring with at least a one-sided infinite derivative is special. Generically, these gradient catastrophe initial conditions for hyperbolic systems (or their parabolic limits) can be expected to evolve instantaneously into either shock discontinuities or rarefaction waves. It is shown that when genuine nonlinearity does not hold uniformly and fails at such singular points, the solutions’ continuity along with their infinite derivatives persist for finite times. All the results are demonstrated in the context of explicit solutions of problems emerging from applications to fluid flows. |
Peranan PBB dalam Dunia Sekarang
| Pengarang | : | Beding, Marcel |
| Nama Majalah/Jurnal | : | Ilmu dan Budaya |
| Volume / Edisi | : | VIII-4, JANUARI (No. 4) |
| Halaman | : | 269-275 |
| Abstrak | : | - |