1,720,971 research outputs found
Model Identification of Continuous Fermentation under Noisy Measurements
No full textThe dynamic model concept plays a central role in automatic control. Understanding the dynamic behavior of chemical and biological processes depends first on understanding the steady state behavior of these processes, then the dynamic characteristics of the process (e.g., the time constant, gain and deadtime) can be used to determine how long it takes to approach the new steady state and what path the process takes. The dynamic models can be used for bioprocess design, analysis of bioprocess control approaches, operator training, and start-up / shutdown strategy development. This paper will present bioprocess model identification of continuous fermentation for gluconic acid production under measurement noise. In this study, the input and output data was generated from first principle dynamic bioprocess model using Contois kinetic model and mass balances. Simulated measurement noises were then added to process variables. The data was then analyzed using System Identification Toolbox in Matlab. The final results obtained are in the form of Laplace-transfer functions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Kendali Sistem Bioreaktor Kontinyu
Full text linkTujuan dalam industri bioproses umumnya adalah memaksimalkan pertumbuhan mikroba dan / atau produksi beberapa senyawa yang dihasilkan oleh mikroorganisme. Untuk mencapai hal ini dengan cara yang efisien, maka diperlukan untuk menjaga lingkungan yang sesuai untuk mikroorganisme setiap saat. Tujuan utama penelitian ini adalah untuk menerapkan algoritma kendali PI (Proporsional integral) dan PID (Proporsional Integral Derivative) untuk suatu sistem bioproses. Kriteria Bode kemudian diterapkan untuk memeriksa kestabilan sistem diikuti dengan penentuan parameter pengendali menggunakan metode TLC (Tyreus-Luyben). Hasil simulasi lintas tertutup menunjukkan kinerja pengendalian yang dapat diterima
Simulasi Pengendali Proporsional Integral pada Proses Penguapan
Full text linkMakalah ini mempresentasikan metode penyaringan signal input gradien sehingga dapat meningkatkan kinerja sistem pengendalian bila terjadi gangguan (noise) pada pembacaan sensor. Sistem pengendalian yang dipelajari adalah sistem pengendalian unit penguapan. Cao (2004) telah mempublikasikan suatu strategi pengendalian desentralisasi pada unit operasi penguapan. Keunikan strategi yang diajukan Cao terletak pada perlunya untuk mengendalikan suatu variabel baru yang merupakan fungsi dari data yang berasal dari sensor-sensor yang tersedia. Kondisi optimal pada sistem pengendalian yang ditinjau perlu dijabarkan terlebih dahulu secara matematis dan dinyatakan sebagai gradien yang merupakan fungsi dari berbagai variabel proses. Gradien tersebut kemudian dikendalikan dengan tujuan lebih lanjut untuk mengendalikan variabel sebenarnya. Keuntungan penerapan saringan signal input gradien pada studi ini dinyatakan dalam reduksi biaya operasi yang dibandingkan dengan pengendalian gradien tanpa penyaringan
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Metode Optimasi Pada Sistem Pengendalian Proses Tangki Pemanas Berpengaduk
Full text linkPada penelitian ini, penyetelan pengendali PID (Proportional Integral Derivative) dilakukan dengan metode optimasi dan hasil akhirnya dibandingkan dengan metode penyetelan lain (yaitu metode sintesa langsung dan Ziegler-Nichols). Tujuan penelitian adalah mendapatkan response output terbaik ketika terjadi perubahan set point dan terjadi gangguan. Penyetelan pengendali adalah proses yang berguna dalam menetapkan parameter pengendali yang dapat mempengaruhi response output dari perubahan setpoint (masalah servo) maupun ketika terjadi gangguan (masalah regulatori). Kinerja pengendali dapat dievaluasi dari harga SSE (Sum Squares of Error) ketika sistem dikendalikan oleh pengendali PID yang disetel dengan metode tertentu. Hasil penelitian menunjukkan bahwa metode optimasi tampak lebih baik dari metode lainnya karena memberikan kinerja terbaik
- …
