Simulated Annealing for Location Area Planning in Cellular networks

LA planning in cellular network is useful for minimizing location management cost in GSM network. In fact, size of LA can be optimized to create a balance between the LA update rate and expected paging rate within LA. To get optimal result for LA planning in cellular network simulated annealing algorithm is used. Simulated annealing give optimal results in acceptable run-time.Comment: 7 Pages, JGraph-Hoc Journa

Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed

A pressure control analysis of cryogenic storage systems

Self-pressurization of cryogenic storage tanks due to heat leak through the thermal protection system is examined along with the performance of various pressure control technologies for application in microgravity environments. Methods of pressure control such as fluid mixing, passive thermodynamic venting, and active thermodynamic venting are analyzed using the homogeneous thermodynamic model. Simplified equations suggested may be used to characterize the performance of various pressure control systems and to design space experiments

Self-pressurization of a flightweight liquid hydrogen tank: Effects of fill level at low wall heat flux

Experimental results are presented for the self pressurization and thermal stratification of a 4.89 cu m liquid hydrogen storage tank subjected to low heat flux (2.0 and 3.5 W/sq m) in normal gravity. The test tank was representative of future spacecraft tankage, having a low mass to volume ratio and high performance multilayer thermal insulation. Tests were performed at fill levels of 29 and 49 pcts. (by volume) and complement previous tests at 83 pct. fill. As the heat flux increases, the pressure rise rate at each fill level exceeds the homogeneous rate by an increasing ratio. Herein, this ratio did not exceed a value of 2. The slowest pressure rise rate was observed for the 49 pct. fill level at both heat fluxes. This result is attributed to the oblate spheroidal tank geometry which introduces the variables of wetted wall area, liquid-vapor interfacial area, and ratio of side wall to bottom heating as a function of fill level or liquid depth. Initial tank thermal conditions were found to affect the initial pressure rise rate. Quasi steady pressure rise rates are independent of starting conditions

Towards the Formal Reliability Analysis of Oil and Gas Pipelines

It is customary to assess the reliability of underground oil and gas pipelines in the presence of excessive loading and corrosion effects to ensure a leak-free transport of hazardous materials. The main idea behind this reliability analysis is to model the given pipeline system as a Reliability Block Diagram (RBD) of segments such that the reliability of an individual pipeline segment can be represented by a random variable. Traditionally, computer simulation is used to perform this reliability analysis but it provides approximate results and requires an enormous amount of CPU time for attaining reasonable estimates. Due to its approximate nature, simulation is not very suitable for analyzing safety-critical systems like oil and gas pipelines, where even minor analysis flaws may result in catastrophic consequences. As an accurate alternative, we propose to use a higher-order-logic theorem prover (HOL) for the reliability analysis of pipelines. As a first step towards this idea, this paper provides a higher-order-logic formalization of reliability and the series RBD using the HOL theorem prover. For illustration, we present the formal analysis of a simple pipeline that can be modeled as a series RBD of segments with exponentially distributed failure times.Comment: 15 page

Perbandingan Pendekatan Konstruktivisme antara Model Pembelajaran Discovery Learning dan Reception Learning terhadap Kemampuan Berpikir Kritis dan Hasil Belajar Peserta Didik Kelas X SMA Negeri 3 Takalar

Penelitian ini bertujuan untuk mengetahui perbedaan yang signifikan kemampuan berfikir kritis dan hasil belajar peserta didik kelas X SMA Negeri 3 Takalar dengan menggunakan model pembelajaran Discovery Learning dan Reception Learning. Metode penelitian yang digunakan yaitu Quasi Eksperimen Design dengan menggunakan desain Nonequivalent Control Group Design, dengan jumlah populasi yaitu seluruh kelas X SMA Negeri 3 Takalar. Teknik pengambilan sampel dalam penelitian ini yaitu Simple Random Sampling yaitu kelas X1 sebagai kelas eksperimen dengan jumlah peserta didik sebanyak 36 orang dan kelas X5 sebagai kelas kontrol dengan jumlah peserta didik sebanyak 34 orang. Instrumen pengumpulan data yang digunakan adalah tes untuk mengetahui kemampuan berpikir kritis dan hasil belajar peserta didik dengan menggunakan model pembelajaran Discovery Learning dan Reception Learning. Data tersebut kemudian dianalisis dengan menggunakan analisis deskripsi dan inferensial. Analisis deskripsi untuk mengetahui deskripsi kemampuan berpikir kritis dan hasil belajar peserta didik dengan menggunakan model pembelajaran Discovery Learning dan Reception Learning serta analisis inferensial untuk mengetahui perbedaan yang signifikan dari rata-rata kemampuan berfikir kritis dan hasil belajar peserta didik yang menggunakan model pembelajaran Discovery Learning dan Reception Learning. Berdasarkan hasil penelitian untuk kemampuan berpikir kritis diperoleh nilai sign (0,000 0,05) maka H0 diterima artinya tidak terdapat perbedaan antara hasil belajar peserta didik yang diajar dengan model pembelajaran Discovery Learning dan Reception Learning. Penelitian ini diharapkan perlu dilakukan penelitian serupa dengan mengembangkan pendekatan dari variabel yang lain dan dapat dilakukan penelitian yang sama tetapi dengan materi yang lain

Western Influences in the Arabic Literature of Egypt and Syria Between 1820 and 1879.

The French invasion of Egypt and Syria in 1798 marks the dawn of the Renascence of Arabic literature and the infiltration into it of western influences. Of the three obvious sources of these influences, French, Italian and English, the first predominates. French influence in Egypt was disseminated by numerous agencies. The first virile agency was the French invasion. The enthusiasm of the Viceroy Muhammad Ali for French culture created new agencies, such as the educational missions, the technical schools, the School of Languages and the translation bureau. These agencies produced their full effect in the reign of Ismail Pasha and out of them grew indigenous agencies, vis., journalism, the Jamiyat al-Maarif, the Dar al-Ulum and the embryonic nationalist party, which combined to speed up westernization. The most prominent exponents of the renascence in Egypt were Rifaah Bey, Abu Soud, Saleh Majdi Bey, All Mubarak Pasha, Abdallah Pasha Fikri and Othman Jalal. In Syria other agencies operated. French political propaganda, the activities of French and American missionaries and the ecclisiastical connection of native Christians with Rome combined to create a new atmosphere. The writings of Roshaid ad-Dahdah, Rizqallah Hassun and others introduced new element and the learned coterie which Cornelius Van Dyck formed with Shaikj Yusuf al-Asir, Butrus al-Bustani and Nasif al-Yaziji gave a vigorous impulse to the new literary movements. But even more substantial and effective was the contribution of the Syrian Ahmad Faris Shidyaq whose conversion to Islam was followed by an active literary and Journalistic career at Constantinople. His Journal, Al Jawaib with its press focussed the best productions of the Arab mind, past and present. In the final chapter the effect of these influences on Arabic literary style is discussed