Three-dimensional unstructured grid generation via incremental insertion and local optimization

Algorithms for the generation of 3D unstructured surface and volume grids are discussed. These algorithms are based on incremental insertion and local optimization. The present algorithms are very general and permit local grid optimization based on various measures of grid quality. This is very important; unlike the 2D Delaunay triangulation, the 3D Delaunay triangulation appears not to have a lexicographic characterization of angularity. (The Delaunay triangulation is known to minimize that maximum containment sphere, but unfortunately this is not true lexicographically). Consequently, Delaunay triangulations in three-space can result in poorly shaped tetrahedral elements. Using the present algorithms, 3D meshes can be constructed which optimize a certain angle measure, albeit locally. We also discuss the combinatorial aspects of the algorithm as well as implementational details

Kajian Ekonomi Tentang Kemiskinan Di Perdesaan Propinsi Sumatera Barat

This research is aimed to study problem of poverty in rural areas of West Sumatera. Operationally, this study has four objectives: (1) to analyze factors determining poverty, such as: land tenure, technology, education, health, access into institutional economies, and alternative profession; (2) to seek the relative poverty as indicated by land tenure distribution and income distribution; (3) to analyze discrepancies in land tenure distribution and income distribution between households clasified poor and not poor; and (4) to analyze discrepancies in income distribution between households with alternative professions and those without alternative professions;One of five hypotheses in this research turn out to be empirically unsupported; The difference between land tenure distribution among households classified not poor is insignificant. This may be due to the fact that this research is carried out in villages whose conditions are quite similar so that land tenure distribution between both categories of households does not vary

The Birds of the Highlands of South-West Saudi Arabia and adjacent parts of the Tihama: July 2010

The objective of the survey was to compare habitats and bird life in the Asir region, particularly Jebal Souda and the Raydah escarpment protected area of the Saudi Wildlife Commission, and adjacent regions of the tihama, with those observed in July 1987 (Jennings, et al., 1988). The two surveys were approximately the same length and equal amounts of time were spent in the highlands and on the tihama. A number of walked censuses were carried out during 2010 on Jebal Souda, using the same methodology as walked censuses in 1987, and the results are compared. Broadly speaking the comparison of censuses revealed that in 2010 there were less birds and reduced diversity on the Jebal Souda plateau, compared to 1987. However in the Raydah reserve the estimates of breeding bird populations compiled in the mid 1990s was little changed as far as could be assessed in 2010. The highland region of south-west Saudi Arabia, especially Jebal Souda, has been much developed since the 1987 survey and is now an important internal recreation and resort area. This has lead to a reduction in the region’s importance for terraced agriculture. These changes may be a contributing factor to changes in bird numbers on the plateau. Subsidiary tasks that arose during the 2010 survey were to help locate satellite tagged Bald Ibises Geronticus eremita from Syria which were transiting Saudi Arabia at the time. Secondly to search for the Asir subspecies of the Eurasian Magpie Pica pica asirensis, which is endemic to the south-west Saudi Arabia highlands, and is reported to be in decline. A separate team searching for the Bald Ibis located some individuals and one was found dead. Few Magpies were located and it seems clear that this very scarce bird has declined further in numbers in recent years. A number of interesting records of birds were obtained, especially on the tihama, where two new birds for Saudi Arabia were observed, Black-headed Heron Ardea melanocephala and Painted Snipe Rostratula benghalensis and one species, Glossy Ibis Plegadis falcinellus was found breeding for the first time in the Arabian Peninsula. Some recommendations for the protection and management of the Raydah reserve are presented. A systematic list of all birds seen is provided

Perbandingan Hasil Belajar Siswa Yang Menggunakan Alat Peraga Benda Dua Dimensi Dengan Yang Menggunakan Alat Peraga Benda Tiga Dimensi Pada Pokok Bahasan Bangun Ruang: Kubus Dan Balok (Studi Eksperimen Kelas VIII Di SMP Negeri 1 Talun, Kab. Cirebon)

Salah satu karakteristik matematika adalah mempunyai objek yang bersifat abstrak. Sifat abstrak ini menyebabkanbanyak siswa mengalami kesulitan dalam mempelajari matematika. Sehingga siswa merasa bosan dan tidak tertarik dalammempelajari matematika. Salah satu cara untuk mengatasi hal tersebut adalah dengan menggunakan alat bantupembelajaran, yaitu alat peraga benda dua dimensi dan alat peraga benda tiga dimensi pada pokok bahasan yang sama.Tujuan dari penelitian ini yaitu untuk mengetahui hasil belajar siswa yang menggunakan alat peraga benda duadimensi dan untuk siswa yang menggunakan alat peraga benda tiga dimensi, serta untuk mengetahui perbedaan hasil belajarsiswa antara yang menggunakan alat peraga benda dua dimensi dan yang menggunakan alat peraga benda tiga dimensi.Hasil belajar adalah hal yang selalu menjadi orientasi dari setiap pelaksanaan proses pembelajaran. Oleh karena itu,guru perlu memilih dan menggunakan alat peraga yang sesuai dengan tujuan pembelajaran, supaya pembelajaran lebihbervariasi, materi yang disampaikan mudah dipahami, dan siswa lebih termotivasi dalam belajar, sehingga dapatmenghasilkan hasil belajar yang lebih baik.Metode yang digunakan dalam penelitian ini adalah metode eksperimen dengan pendekatan kuantitatif, sedangkanuntuk pengumpulan data melalui observasi, studi dokumentasi dan pemberian soal tes. Populasi target dalam penelitian iniadalah seluruh siswa kelas VIII semester genap tahun ajaran 2008/2009. Kemudian diambil sampel dengan menggunakanteknik cluster sample dan dipilih kelas VIIIDsebagai kelompok 1 dengan alat peraga benda dua dimensi dan dipilih kelasVIIIEsebagai kelompok 2 dengan alat peraga benda tiga dimensi. Setelah data diperoleh kemudian dianalisis dengan ujinormalitas, uji homogenitas, uji t, serta uji hipotesis.t dengan tarafnyata α = 0,05 dan derajat kebebasan (dk) = (40 + 38 – 2) = 76. Karena nilai 76 tidak terdapat dalam daftar distribusiDari hasil data uji hipotesis dengan perhitungan uji t diperoleh hargastudent's t maka ditentukan dengan cara interpolasi yang diperoleh hargatabelt= 3,22. Sedangkanhitungt = 1,99. Karenat yaitu 3,22 >1,99, maka Ho ditolak dan Ha diterima, artinya terdapat perbedaan hasil belajar matematika antara siswa yangt>hitungmenggunakan alat peraga benda dua dimensi dengan siswa yang menggunakan alat peraga benda tiga dimensi. Dalam halini hasil belajar matematika siswa yang menggunakan alat peraga benda tiga dimensi lebih baik daripada siswa yangmenggunakan alat peraga benda dua dimensi, dengan uji t untuk alat peraga benda dua dimensi adalah 7,63 dan untuk alatperaga benda tiga dimensi adalah 12,08

Extending the scope of microscopic solvability: Combination of the Kruskal-Segur method with Zauderer decomposition

Successful applications of the Kruskal-Segur approach to interfacial pattern formation have remained limited due to the necessity of an integral formulation of the problem. This excludes nonlinear bulk equations, rendering convection intractable. Combining the method with Zauderer's asymptotic decomposition scheme, we are able to strongly extend its scope of applicability and solve selection problems based on free boundary formulations in terms of partial differential equations alone. To demonstrate the technique, we give the first analytic solution of the problem of velocity selection for dendritic growth in a forced potential flow.Comment: Submitted to Europhys. Letters, No figures, 5 page