Modelling Aging Characteristics in Citation Networks

Growing network models with preferential attachment dependent on both age and degree are proposed to simulate certain features of citation network noted in \cite{red2}. In this directed network, a new node gets attached to an older node with the probability $\sim K(k)f(t)$ where the degree and age of the older node are $k$ and $t$ respectively. Several functional forms of $K(k)$ and $f(t)$ have been considered. The desirable features of the citation network can be reproduced with $K(k) \sim k^{-\beta}$ and $f(t) \sim \exp(\alpha t)$ with $\beta =2.0$ and $\alpha = -0.2$ and with simple modifications in the growth scheme.Comment: 6 pages, 6 figure

Efektivitas Pembelajaran Matematika Melalui Model Kooperatif Tipe Make a Match Pada Siswa Kelas X IPA SMA Negeri 1 Gowa

Jenis penelitian ini adalah penelitian pra-eksperimen yang melibatkan satu kelas sebagai kelas eksperimen dengan tujuan untuk mengetahui efektivitas pembelajaran matematika melalui model kooperatif tipe make a match pada siswa kelas X IPA SMA Negeri 1 Gowa Tahun Pelajaran 2017/2018. Penelitian ini mengacu pada tiga kriteria keefektifan pembelajaran yaitu hasil belajar matematika siswa tuntas dan meningkat, aktivitas siswa dalam kegiatan pembelajaran matematika, dan respon siswa terhadap pelaksanaan pembelajaran matematika dengan model kooperatif tipe make a match. Desain penelitian yang digunakan adalah One Group Pretest-Posttest Design, yaitu sebuah eksperimen yang dilaksanakan tanpa adanya kelompok pembanding (kontrol). Sampel penelitian dalam penelitian ini yaitu siswa kelas X IPA 2 SMA Negeri 1 Gowa sebanyak 31 orang sebagai kelas yang diterapkan model kooperatif tipe make a match. Hasil penelitian menunjukkan bahwa: (1) Skor rata-rata tes hasil belajar matematika siswa melalui model kooperatif tipe make a match adalah 86,93%. (2) Rata-rata persentase aktivitas siswa untuk setiap indikator mencapai kriteria efektif, yaitu 81,93%.(3) Angket respon siswa menunjukkan bahwa respon positif siswa terhadap model kooperatif tipe make a match yaitu 90,83%, dan mencapai kriteria efektif. Hasil analisis inferensial menunjukan bahwa: (1) uji normalitas posttest dengan nilai Pvalue=0,07 > α =0,05 dan uji normalitas gain dengan nilai Pvalue=0,2 > α =0,05 berdistribusi normal. (2) Pengujian hipotesis terdiri dari (a) ketuntasan klasikal postest telah tercapai dengan Zhitung =3,36> Ztabel= 1,645 maka Ho ditolak, (b) peningkatan hasil belajar matematika siswa sudah tercaoai dengan nilai pvalue = 0,000 < α = 0,05 maka Ho ditolak. Berdasarkan hasil penelitian tersebut, dapat disimpulkan bahwa model kooperatif tipe make a match efektif diterapkan dalam pembelajaran matematika pada siswa kelas X IPA SMA Negeri 1 Gowa

A Complete Survey of the Central Molecular Zone in NH3

We present a map of the major part of the central molecular zone (CMZ) of simultaneous observations in the NH3 (J,K) = (1,1) and (2,2) lines using the Kagoshima 6-m telescope. The mapped area is -1.000 < l < 1.625 deg, -0.375 < b < +0.250 deg. The kinetic temperatures derived from the (2,2) to (1,1) intensity ratios are 20--80 K or exceed 80 K. The gases corresponding to temperature of 20--80 K and > 80 K contain 75% and 25% of the total NH3 flux, respectively. These temperatures indicate that the dense molecular gas in the CMZ is dominated by gas that is warmer than the majority of the dust present there. A comparison with the CO survey by Sawada et al. (2001) shows that the NH3 emitting region is surrounded by a high pressure region on the l-v plane. Although NH3 emission traces dense gas, it is not extended into a high pressure region. Therefore, the high pressure region is less dense and has to be hotter. This indicates that the molecular cloud complex in the Galactic center region has a ``core'' of dense and warm clouds which are traced by the NH3 emission, and an ``envelope'' of less dense and hotter gas clouds. Besides heating by ambipolar diffusion, the hot plasma gas emitting the X-ray emission may heat the hot ``envelope''.Comment: 21 pages, 14 figures, accepted for PAS

Modelling temporal and spatial features of collaboration network

The collaboration network is an example of a social network which has both non-trivial temporal and spatial dependence. Based on the observations of collaborations in Physical Review Letters, a model of collaboration network is proposed which correctly reproduces the time evolution of the link length distributions, clustering coefficients, degree distributions and assortative property of real data to a large extent.Comment: 8 pages, 10 figures; follow up work on arXiv.org/physics/0511181; accepted for publication in IJMP