1,720,978 research outputs found
SIZING OPTIMIZATION OF STANDALONE PHOTOVOLTAIC SYSTEM FOR RESIDENTIAL LIGHTING
Get PDFThis study presents a sizing methodology to optimize photovoltaic array and
battery storage in a standalone photovoltaic (PV) system with lighting load. Sizing
using the deterministic method was carried out for initial design. Stochastic method
by mean of Loss of Power Supply Probability (LPSP) calculation was developed
using daily weather data input. The weather data consists of ambient temperature,
relative humidity and solar radiation. An estimation method of hourly solar radiation
data is also developed in this study to complete any missing solar radiation data in the
dataset. Then, complete time-series dataset can be used for LPSP calculation and
system simulation. Size optimization was carried out using a graphical method.
System size was optimized based on desired system performance (indicated by LPSP
value) and minimum cost that consist of Capital Cost and Life-cycle cost. In addition,
Excess energy value is used as over-design indicator. A comparison of sizing
optimization methods was carried out, and it was found that the design space
approach giving flexibility in the selection of PV panel and battery capacity compared
to other methods. The sizing result of this method is a configuration of 500Wp PV
array and 400Ah battery. Economic analyses, including cost of the energy and
payback period for selected configuration are studied. A simulation model was
developed using TRNSYS 16 to test the sizing results. Experimental data was used to
validate the simulation results. Simulation validation shows that result accuracy has
improved. The results indicated that Root Mean Square Error (RMSE) between
simulated and measured battery voltage has decreased by 50% compared to previous
work. The validated simulation model then was used to test and analyse the selected
PV system configuration
Rancang Bangun Fermentor Yogurt dengan Sistem Kontrol Logika Fuzzy Menggunakan Mikrokontroler ATMega32
Get PDFYogurt is milk fermented product that becomes popular recently. In yogurt processing, fermenter is the main device. Lactobacillus sp. and Streptococcus sp. are two probiotic bacteria species that are common to be used in yogurt fermentation process. Both bacteria grow well in a specific range of temperature between 40-45 C, so temperature control in fermenter operational becomes one of the important things to ensure speed and quality of fermentation process. Fermentation process is a process with high degree of uncertainty and categorized as non-linear time invariant system. Thus, classical control system method is difficult to be implemented. To overcome this issue, intelligent control system can be implemented to yogurt's fermenter temperature control. One of intelligent control system method that can be implemented is fuzzy logic-based control system. In this study, fuzzy control system has been designed and implemented for fermenter temperature control. Control system algorithm is integrated in ATMega16 (for On-Off logic control) and ATMega32 (for Fuzzy Logic control) microcontrollers. Experimental results of fermenter control system shows that temperature profile of fermenter with fuzzy logic control system is more stable by settling time around an hour and 15 minutes and error average of -0.36 oC. Fermentation process for 16 hours with fuzzy logic controller produce yogurt with pH value of 3.66, total number of Lactobacillus sp. is 4.85 x 10 cfu/mL and Streptococcus sp. is 1.34 x 106 cfu/mL
MENINGKATKAN EFISIENSI MESIN EKSTRAKSI BETA KAROTEN DENGAN ULTRASONIC TRANSDUCER ARRAY BERBASIS ARDUINO UNO
No full textIndustri pangan Indonesia berkontribusi besar terhadap PDB dengan pertumbuhan tahunan 3,57%, namun keamanan pangan menjadi perhatian akibat penggunaan pewarna sintetis terlarang seperti rhodamin B dan methanyl yellow. Keterbatasan produksi pewarna alami menjadi tantangan, meski Indonesia kaya akan pigmen alami seperti beta karoten, pigmen antioksidan yang menghasilkan warna kuning hingga oranye. Beta karoten dapat diekstraksi dari komoditas seperti labu kuning (Cucurbita moschata), namun metode ekstraksi konvensional seperti maserasi membutuhkan waktu lama, sementara metode ultrasonik tanduk getar berbiaya tinggi dan berisiko degradasi senyawa. Solusi inovatif berupa mesin ekstraksi berbasis ultrasonic transducer array dengan Arduino Uno dikembangkan, terdiri atas reaction chamber, cooling chamber, dan control panel. Mesin ini, dengan daya 266 watt, menghasilkan kadar beta karoten tertinggi sebesar 4941,12 µg/g, lebih efisien dibanding teknologi lain. Mesin ini memaksimalkan hasil ekstraksi serta mengefisiensikan waktu, biaya, dan penggunaan bahan ekstraksi.Kata Kunci—Beta Karoten, Mesin Ekstraksi, Pewarna, Pewarna Alami, Labu Kuning.
Hitung Cepat Buah Jeruk Berbeda Kultivar pada Pohon berbasis Citra Smartphone dan Kecerdasan Buatan
Get PDFCurrently, predictions of orange fruit yield in an orchard are still done manually, namely by sampling manually to count the number of oranges on the tree. This method is not effective and the accuracy of predictions cannot be guaranteed. Automation in the process of counting citrus fruit on trees to predict yield can be done with computer vision using artificial intelligence models for object detection. One of the proposed model solutions that can be used for object detection is by using You Only Look Once (YOLO) architecture. However, the performance of the YOLO model for different varieties of orange trees in Indonesia is not yet known. Therefore, in this research, the development of the YOLOv5 model was carried out to quickly count orange fruit on trees of different varieties including the stages of image capture, image resizing, segmentation, model training with hyperparameters such as batch size and epoch, as well as model evaluation. In this study, the primary image dataset taken consisted of images of orange trees with two different cultivars, namely Pontianak Siamese oranges and Terigas Tangerines which have different characteristics. Then the YOLOv5 model is trained using labeled image data. The YOLOv5 model is trained with variations of hyperparameters and then the results are compared. The best model results in Siam Pontianak have a single label configuration in batch size 4 with parameters Mean Average Precision (mAP50), accuracy, precision, recall, and F1-score which produces a value of 0.88; 0.712; 0.853; 0.822; and 0.8372. Meanwhile, the best model results in Keprok Terigas have a single label configuration in batch size 10 with parameters Mean Average Precision (mAP50), accuracy, precision, recall, and F1-score which produces a value of 0.933; 0.75; 0.913; 0.878; and 0.8951.Saat ini, prediksi yield buah jeruk pada suatu kebun jeruk masih dilakukan secara manual, yaitu dengan melakukan sampling menghitung manual jumlah buah pada pohon. Metode ini tidak efektif dan keakuratan prediksi tidak dapat dijamin. Otomasi dalam proses perhitungan buah jeruk pada pohon untuk memprediksi yield dapat dilakukan dengan komputer visi dengan menggunakan model kecerdasan buatan untuk deteksi obyek. Salah satu model yang dapat digunakan adalah model dengan arsitektur You Only Look Once (YOLO. Namun, belum diketahui performa model YOLO untuk pohon jeruk dengan varietas berbeda yang ada di Indonesia. Oleh karenanya, pada penelitian ini dilakukan pengembangan model YOLOv5 untuk menghitung cepat buah jeruk pada pohon dengan varietas yang berbeda. Pada penelitian ini dataset citra primer yang diambil terdiri dari citra pohon jeruk dengan dua kultivar yang berbeda yaitu jeruk Siam Pontianak dan Keprok Terigas yang memiliki karakteristik berbeda. Kemudian model YOLOv5 dilatih dengan menggunakan data citra yang telah dilabeli. Model YOLOv5 dilatih dengan variasi hyperparameter dan kemudian dibandingkan hasilnya. Hasil model terbaik pada Siam Pontianak memiliki konfigurasi label tunggal pada batch size 4 dengan parameter Mean Average Precision (mAP50), akurasi, presisi, recall, dan skor-F1 yang menghasilkan nilai sebesar 0,88; 0,712; 0,853; 0,822; dan 0,8372. Sementara itu, Hasil model terbaik pada Keprok Terigas memiliki konfigurasi label tunggal pada batch size 10 dengan parameter Mean Average Precision (mAP50), akurasi, presisi, recall, dan skor-F1 yang menghasilkan nilai sebesar 0,933; 0,75; 0,913; 0,878; dan 0,8951
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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