Reseñas

Steven JAY PEITZMAN, Dropsy, dialysis, transplant. A short history of failing kidney

Two maximum principles for a nonlinear fourth order equation from thin plate theory

We develop two maximum principles for a nonlinear equation of fourth order that arises in thin plate theory. As a consequence, we obtain uniqueness results for the corresponding fourth order boundary value problem under Navier boundary conditions as well as some bounds of interest

Un enfer pavé de bonnes intentions : interdire les killer robots

National audienc

Perencanaan Bisnis Penyewaan Peralatan Video untuk Stasiun Televisi di Indonesia

Penelitian ini merupakan studi mengenai peluang dari rencana bisnis yaitu “Penyewaan Peralatan Video untuk Stasiun Televisi di Indonesia''. Tujuan penelitian ini untuk mengetahui seberapa besar prospek keuntungan dari kegiatan USAha atau bisnis jasa Penyewaan Peralatan Video sekaligus memberikan bantuan dan menjadi solusi atas kebutuhan Stasiun Televisi dalam penyediaan peralatan untuk Produksi suatu Program Acara. Metode analisis yang digunakan dalam penelitian ini adalah Metode Analisis Deskriptif dengan alasan metode ini dapat merumuskan dan menafsirkan data yang ada sehingga menghasilkan gambaran yang jelas mengenai jenis USAha yang akan dijalankan secara umum. Instrumen yang digunakan untuk membuat analisis profitabilitas bisnis ini adalah analisis SWOT dan analisis proyeksi laporan keuangan berdasarkan asumsi logis sesuai kondisi yang sebenarnya terjadi. Ukuran untuk menentukan prospek keuntungan bisnis ini bersandar pada analisis ini adalah jangka waktu pengembalian modal dan proyeksi keuntungan yang diharapkan. Dalam bagian akhir penelitian ini, akan diperoleh gambaran bahwa jangka waktu pengembalian modal dapat dicapai dalam 12 (duabelas) bulan, sehingga pada bulan ke 13 (tigabelas) dan seterusnya sudah dapat diperoleh keuntungan yang tetap, yaitu sebesar Rp. 390,191,000,- perbulan

Uniqueness in some higher order elliptic boundary value problems in n dimensional domains

We develop maximum principles for several P functions which are defined on solutions to equations of fourth and sixth order (including a equation which arises in plate theory and bending of cylindrical shells). As a consequence, we obtain uniqueness results for fourth and sixth order boundary value problems in arbitrary n dimensional domains

Dick effect in a pulsed atomic clock using Coherent Population Trapping

The Dick effect can be a limitation of the achievable frequency stability of a passive atomic frequency standard when the ancillary frequency source is only periodically sampled. Here we analyze the Dick effect for a pulsed vapor cell clock using coherent population trapping (CPT). Due to its specific interrogation process without atomic preparation nor detection outside of the Ramsey pulses, it exhibits an original shape of the sensitivity function to phase noise of the oscillator. Numerical calculations using a three-level atom model are successfully compared with measurements; an approximate formula of the sensitivity function is given as an easy-to-use tool. A comparison of our CPT clock sensitivity to phase noise with a clock of the same duty cycle using a two-level system reveals a higher sensitivity in the CPT case. The influence of a free-evolution time variation and of a detection duration lengthening on this sensitivity is studied. Finally this study permitted to choose an adapted quartz oscillator and allowed an improvement of the clock fractional frequency stability at the level of 3.2x10-13 at 1

An empirical study of authentication methods to secure e-learning system activities against impersonation fraud

The demand for e – learning systems in both academic and non – academic organizations has increased the need to improve security against impersonation fraud. Although there are a number of studies focused on securing Web - based systems from Information Systems (IS) misuse, research has recognized the importance of identifying suitable levels of authenticating strength for various activities. In e - learning systems, it is evident that due to the variation in authentication strength among controls, a ‘one size fits all’ solution is not suitable for securing diverse e - learning activities against impersonation fraud. The focus of this exploratory study was to investigate what levels of authentication strength users perceive to be most suitable for activities in e - learning systems against impersonation fraud and aimed to assess if the ‘one size fits all’ approach that is mainly used is valid when it comes to securing e - learning activities from impersonation fraud. A sample of 1,070 e - learners was analyzed using descriptive statistics and exploratory factor analysis to uncover suitable levels of authentication strength to secure e - learning activities against impersonation fraud. The findings determined that there is a specific set of e – learning activities that have high potential for impersonation and need a moderate to high level of authentication strength to reduce the threat