A queueing theory description of fat-tailed price returns in imperfect financial markets

In a financial market, for agents with long investment horizons or at times of severe market stress, it is often changes in the asset price that act as the trigger for transactions or shifts in investment position. This suggests the use of price thresholds to simulate agent behavior over much longer timescales than are currently used in models of order-books. We show that many phenomena, routinely ignored in efficient market theory, can be systematically introduced into an otherwise efficient market, resulting in models that robustly replicate the most important stylized facts. We then demonstrate a close link between such threshold models and queueing theory, with large price changes corresponding to the busy periods of a single-server queue. The distribution of the busy periods is known to have excess kurtosis and non-exponential decay under various assumptions on the queue parameters. Such an approach may prove useful in the development of mathematical models for rapid deleveraging and panics in financial markets, and the stress-testing of financial institutions

Composition dependent magnetic properties of iron oxide - polyaniline nanoclusters

Gamma - Iron Oxide prepared by sol -gel process was used to produce nanocomposites with polyaniline of varying aniline concentrations. TEM shows the presence of chain like structure for lower polyaniline concentration. The room temperature hysteresis curves show finite coercivity of 160 Oe for all the composites while the saturation magnetization was found to decrease with increasing polymer content. ZFC - FC magnetisation measurements indicate high blocking temperatures. It is believed that this indicates a strongly interacting system, which is also shown by our TEM results. Monte Carlo simulations performed on a random anisotropy model with dipolar and exchange inteactions match well with experimental results.Comment: 9 (nine) pages, 6 figures (jpeg and eps

Effects of the Nearest-Neighbour Coulomb Interactions on the Ground State of the Periodic Anderson Model

The magnetic and non-magnetic ground states of the periodic Anderson model with Coulomb interaction between $f$-electrons on the nearest-neighbour(NN) sites are investigated using a variational method, which gives exact calculation of the expectation values in the limit of infinite dimensions. It is shown that for a critical value of NN Coulomb interactions the magnetic ground state of the periodic Anderson model in the Kondo regime is unstable. Factors in terms of the physical processes responsible for instability of the magnetic ground state are also discussed. Our study indicates the importance of the NN Coulomb interactions for correlated two band models.Comment: RevTeX, 6 pages, 5 figures, to appear in Phys. Rev.

Biodiversitas Burung pada Beberapa Tipe Habitat di Kampus Universitas Sam Ratulangi Manado dalam Masa Pandemi Covid-19

Biodiversitas burung dapat dijadikan sebagai bio-indikator biologis berkaitan dengan kesehatan lingkungan serta sebagai tolok ukur kelestarian dalam pembangunan dan pemanfaatan sumber daya alam. Penelitian ini bertujuan untuk mengidentifikasi tingkat biodiversitas jenis burung di Kampus Universitas Sam Ratulangi di masa pandemi Covid 19 dan untuk mengetahui perbandingan biodiversitas di beberapa tipe habitat berdasarkan indeks nilai keanekaragaman Shannon-Wiener. Penelitian ini menggunakan metode purposive sampling yang dilaksanakan pada bulan November-Desember 2020. Berdasarkan hasil penelitian ditemukan 21 jenis  burung, yaitu Passer montanus, Pycnonotus aurigaster, Hirundo tahitica, Halcyon cloris, Nectarinia jugularis, Anthreptes malacensis, Geopelia striata, Streptopelia chinensis, Columba livia, Collocalia esculenta, Gallirallus torquatus, Lonchura oryzivora, Lonchura malacca, Corvus enca, Eudynamis melanorhyncha, Cacomantis sepulcralis, Coracina bicolor, Motacilla cinerea, Egretta garzetta, Ardea purpurea, dan Haliastur indus. Burung yang paling banyak ditemukan adalah Passer montanus sedangkan burung yang paling sedikit adalah Ardea purpurea dan Egretta garzetta dengan indeks keanekaragaman termasuk dalam kategori sedang melimpah yaitu 1,873

Cooperating Agents for 3D Scientific Data Interpretation

Many organizations collect vast quantities of three-dimensional (3-D) scientific data in volumetric form for a range of purposes, including resource exploration, market forecasting, and process modelling. Traditionally, these data have been interpreted by human experts with only minimal software assistance. However, such manual interpretation is a painstakingly slow and tedious process. Moreover, since interpretation involves subjective judgements and each interpreter has different scientific knowledge and experience, formulation of an effective interpretation often requires the cooperation of numerous such experts. Hence, there is a pressing need for a software system in which individual interpretations can be generated automatically and then refined through the use of cooperative reasoning and information sharing. To this end, a prototype system, SurfaceMapper, has been developed in which a community of cooperating software agents automatically locate and display interpretations in a volume of 3-D scientific data. The challenges and experiences in designing and building such a system are discussed. Particular emphasis is given to the agents' interactions and an empirical evaluation of the effectiveness of different cooperation strategies is presented

Magnetic properties of polypyrrole - coated iron oxide nanoparticles

Iron oxide nanoparticles were prepared by sol -gel process. Insitu polymerization of pyrrole monomer in the presence of oxygen in iron oxide ethanol suspension resulted in a iron oxide - polypyrrole nanocomposite. The structure and magnetic properties were investigated for varying pyrrole concentrations. The presence of the gamma - iron oxide phase and polypyrrole were confirmed by XRD and FTIR respectively. Agglomeration was found to be comparatively much reduced for the coated samples, as shown by TEM. AC susceptibility measurements confirmed the superparamagnetic behaviour. Numerical simulations performed for an interacting model system are performed to estimate the anisotropy and compare favourably with experimental results.Comment: 11 pages,8 figure

Penerapan Pembelajaran Tematik Untuk Meningkatkan Hasil Belajar IPA Materi Pada Lingkungan Siswa Kelas I SDN 018 Letawa Kecamatan Sarjo Kabupaten Mamuju Utara

Penelitian ini bertujuan untuk meningkatkan hasil belajar dengan tema lingkungan pada kelas I SD Negeri 018 Letawa Kecamatan Sarjo Kabupaten Mamuju Utara. Penelitian dilaksanakan dengan dua siklus, dan setiap siklus terdiri dari empat tahap yaitu : Perencanaan, Pelaksanaan, Observsi dan refleksi. Subjek penelitian ini adalah semua siswa kelas I SD Negeri 018 Letawa Kecamatan Sarjo Kabupaten Mamuju Utara Tahun Pelajaran 2012/2013 dengan jumlah siswa 32 orang. Data penelitian ini diperoleh dari observasi kegiatan guru dan kegiatan belajar siswa. Berdasarkan hasil analisa data, pada siklus I diperoleh Daya Serap Individu 69% dan Ketuntasan Belajar Klasikal 75%. Sedangkan Pada siklus II meningkat dengan Daya Serap Individu 75% dan Ketuntasan Belajar Klasikal 81%, serta hasil belajar siswa mengalami peningkatan secara klasikal dari siklus I ke sisklus II yaitu 75,0% ke 81,25%

Almost sure stability of the Euler-Maruyama method with random variable stepsize for stochastic differential equations

In this paper, the Euler–Maruyama (EM) method with random variable stepsize is studied to reproduce the almost sure stability of the true solutions of stochastic differential equations. Since the choice of the time step is based on the current state of the solution, the time variable is proved to be a stopping time. Then the semimartingale convergence theory is employed to obtain the almost sure stability of the random variable stepsize EM solution. To our best knowledge, this is the first paper to apply the random variable stepsize (with clear proof of the stopping time) to the analysis of the almost sure stability of the EM method