Distributed Coupled Multi-Agent Stochastic Optimization

This work develops effective distributed strategies for the solution of constrained multi-agent stochastic optimization problems with coupled parameters across the agents. In this formulation, each agent is influenced by only a subset of the entries of a global parameter vector or model, and is subject to convex constraints that are only known locally. Problems of this type arise in several applications, most notably in disease propagation models, minimum-cost flow problems, distributed control formulations, and distributed power system monitoring. This work focuses on stochastic settings, where a stochastic risk function is associated with each agent and the objective is to seek the minimizer of the aggregate sum of all risks subject to a set of constraints. Agents are not aware of the statistical distribution of the data and, therefore, can only rely on stochastic approximations in their learning strategies. We derive an effective distributed learning strategy that is able to track drifts in the underlying parameter model. A detailed performance and stability analysis is carried out showing that the resulting coupled diffusion strategy converges at a linear rate to an $O(\mu)-$neighborhood of the true penalized optimizer

Linear Convergence of Primal-Dual Gradient Methods and their Performance in Distributed Optimization

In this work, we revisit a classical incremental implementation of the primal-descent dual-ascent gradient method used for the solution of equality constrained optimization problems. We provide a short proof that establishes the linear (exponential) convergence of the algorithm for smooth strongly-convex cost functions and study its relation to the non-incremental implementation. We also study the effect of the augmented Lagrangian penalty term on the performance of distributed optimization algorithms for the minimization of aggregate cost functions over multi-agent networks

Multiwavelength fiber laser based on bidirectional lyot filter in conjunction with intensity dependent loss mechanism

We experimentally demonstrate a multiwavelength fiber laser (MWFL) based on bidirectional Lyot filter. A semiconductor optical amplifier (SOA) is used as the gain medium, while its combination with polarization controllers (PCs) and polarization beam combiner (PBC) induces intensity dependent loss (IDL) mechanism. The IDL mechanism acts as an intensity equalizer to flatten the multiwavelength spectrum, which can be obtained at a certain polarization state. Using different ratio of optical splitter has affected to multiwavelength flatness degradation. Subsequently, when we removed a polarizer in the setup, the extinction ratio (ER) is decreased. Ultimately, with two segments of polarization maintaining fiber (PMF), two channel spacings can be achieved due to splicing shift of 0° and 90°

Dynamics of DNA Bubble in Viscous Medium

The damping effect to the DNA bubble is investigated within the Peyrard-Bishop model. In the continuum limit, the dynamics of the bubble of DNA is described by the damped nonlinear Schrodinger equation and studied by means of variational method. It is shown that the propagation of solitary wave pattern is not vanishing in a non-viscous system. Inversely, the solitary wave vanishes soon as the viscous force is introduced.Comment: 4 pages. arXiv admin note: substantial text overlap with arXiv:1112.471

Implementasi Manajemen Berbasis Sekolah (Mbs) dalam Meningkatkan Profesionalisme Guru di SD Negeri 10 Banda Aceh

Adapun latar belakang masalah dari penelitian ini adalah masih banyak guru yang kurang profesional dibidangnya, seperti adanya guru yang terlambat masuk mengajar, tidak mempunyai perangkat pembelajaran yang lengkap, kurangnya koordinasi antar kepala sekolah dan guru. Penelitian ini bertujuan untuk mengetahui profesionalisme guru melalui implementasi Manajemen Berbasis Sekolah (MBS) di SD Negeri 10 Banda Aceh.Pendekatan yang digunakan dalam penelitian ini adalah kualitatif dengan jenis penelitian deskriptif. Subjek dari penelitian ini adalah guru SD Negeri 10 Banda Aceh berjumlah 10 orang dipilih dengan menggunakan teknik purpossive sampling. Teknik pengumpulan data dengan menggunakan observasi dan wawancara.Data hasil penelitian diolah dengan mereduksi data, penyajian data, dan penarikan kesimpulanHasil penelitian ini menunjukkan bahwa kepala sekolah melakukan diskusi untuk pengambilan kebijakan yang akan diterapkan oleh sekolah, kepala sekolah melakukan evaluasi dengan memeriksa perangkat pembelajaran, kehadiran guru, prestasi belajar siswa dan keaktifan pada UKG yang dilakukan di gugus. Kelulusan siswa setiap tahunnya mencapai 100% lulus. Ini membuktikan prestasi sekolah yang diperoleh melalui keberhasilan siswa, guru-guru memanfaatkan waktu dengan sebaik-baiknya pada peroses belajar mengajar, guru menggunakan berbagai media pembelajaran. Siswa memiliki peningkatan pada hasil belajar dan dengan demikian terlihat peningkatan profesionalisme guru melalui implementasi manajemen berbasis sekolah

Large-scale solar wind flow around Saturn's nonaxisymmetric magnetosphere

The interaction between the solar wind and a magnetosphere is fundamental to the dynamics of a planetary system. Here, we address fundamental questions on the large-scale magnetosheath flow around Saturn using a 3D magnetohydrodynamic (MHD) simulation. We find Saturn's polar-flattened magnetosphere to channel ~20% more flow over the poles than around the flanks at the terminator. Further, we decompose the MHD forces responsible for accelerating the magnetosheath plasma to find the plasma pressure gradient as the dominant driver. This is by virtue of a high-beta magnetosheath, and in turn, the high-MA bow shock. Together with long-term magnetosheath data by the Cassini spacecraft, we present evidence of how nonaxisymmetry substantially alters the conditions further downstream at the magnetopause, crucial for understanding solar wind-magnetosphere interactions such as reconnection and shear flow-driven instabilities. We anticipate our results to provide a more accurate insight into the global conditions upstream of Saturn and the outer planets.Comment: Accepted for publication in Journal of Geophysical Journal: Space Physic