Abstract--Sentiment analysis or opinion mining, which is one of the application of Natural Language Processing (NLP), aims to find a method to facilitate human in communicating with a computer using their common language. To simplify the process of understanding human language, there are three important stages that must be carried out by a computer, which are tokenizing, stemming and filtering. The tokenizing that breaks down the sentence into a single word will make the computer assume all words (token) are the same. If there is a phrase formed from one of unimportant words, which is happened to be in the stoplist, the phrase will be deleted. Solution for the aforementioned problem is tokenizing based on phrase detection using Hidden Markov Model (HMM) POS-Tagger to improve classification performance using Support Vector Machine (SVM). With this approach, computer will be able to distinguish a phrase from others, then store the phrase into a single entity. There is an increase in accuracy by approximately 6% on Dataset I and 3% on Dataset II in the classification process using phrase detection, due to reduction of missing features that usually occurs in the filtering process. In addition, the detection of the phrase-based approach also produces the most optimal classification model, as seen from the ROC value that reaches 0.897. Intisari--Analisis I. PENDAHULUAN A. Latar BelakangDi era informasi seperti saat ini, kemampuan untuk mengolah data menjadi informasi merupakan komoditas yang sangat berharga bagi sebuah organisasi. Partai politik bisa mengetahui popularitas calon presiden yang diusungnya melalui kicauan para pengguna Twitter [1]. Selain itu, dengan banyaknya aplikasi microblogging dan media sosial, hasil analisis dari tulisan atau komentar seorang konsumen bisa digunakan sebagai pendukung manajemen merek dan corporate reputation [2]. Online shop yang berkembang dengan pesat, baik dalam hal jumlah maupun jenis barang yang dijual, juga menyediakan banyak informasi yang bisa digunakan oleh para pelaku bisnis jual beli online [3]. Hal ini menyebabkan munculnya gagasan untuk menilai tanggapan atau ulasan publik terhadap sebuah produk atau kebijakan dari organisasi tertentu yang kemudian digunakan sebagai tolok ukur keberhasilan produk atau kebijaksanaan tersebut. Namun, pekerjaan tersebut akan menjadi sangat berat apabila dilakukan secara manual, karena data yang didapatkan dari aplikasi microblogging dan media sosial mayoritas berupa data tekstual yang tidak terstruktur, sehingga akan memakan banyak waktu dan tenaga bila dilakukan oleh manusia. Oleh sebab itu, dibutuhkan sebuah sistem yang secara otomatis bisa melakukan analisis terhadap data tekstual, yaitu analisis sentimen atau opinion mining.Analisis sentimen atau opinion mining merupakan sebuah kegiatan untuk memahami, mengekstrak, dan mengolah data tekstual secara otomatis untuk mendapatkan informasi sentimen yang terkandung dalam suatu kalimat opini [4]. Sentimen itu sendiri merupakan cerminan dari attitude pembicara atau penulis berkenaan dengan t...
Vehicles technology have been a priority area of research over the last few decades. With the increasing the use of electronic components in the automotive industry to measure conditions around the vehicle, the focus of automotive technology development is now leading to the development of active technology. Information on the speed of conventional vehicles is generally still obtained based on the rotation of the wheel, but there are weakness in the system that is the diference between wheel and road through vehicle also changes wheel radius of the vehicle due to wind tube air preasure that can change at any time. In this research used Inertial Measuring Unit (IMU) 6 axis (accelerometer and gyroscope) which have been done filtering by using Kalman filter in order to make output sensor value more stable, results obtained at the test of 0 m/s had an RMS error of 0.8696 m/s when elevation is +450; 0.0393 m/s when elevation is 00; and 0.3030 m/s when elevation is -450. this research is expected to be an exploration for the development of a decent system that is suitable to be used as vehicle speed estimator which is as reliable as it is by using an existing speedometer on a ground vehicle generally regardless of slippage and changes in wind capacity on wheels.
Document grouping is a necessity among a large number of articles published on internet. Several attempts have been done to improve this grouping process, while majority of the efforts are based on word appearance. In order to improve its quality, the grouping of documents need to be based on topic similarity between documents, instead of the frequency of word appearance. The topic similarity could be known from its latency, since the similarity of the word interpretation are often used in the same context. In the unsupervised learning process, SOM is often used, in which this approach simplifies the mapping of multi-dimension data. This research result shows that implementation of the latent structure decreases characteristic dimension by 32% of the word appearance, hence makes this approach more time efficient than others. The latent structure, however, when implemented on SOM Algorithm, is capable to obtain good quality result compared to word appearance frequency approach. It is then proven by 5% precision improvement, recall improvement of 3%, and another 4% from F-measure. While the achievement is not quite significant, the quality improvement is able to put the dominance of grouping process, compared to the original classification defined by the content provider.
Abstract-Flyback is one of high voltage generation methods using a low voltage source. This method has a simple circuit, which consists of two main components for generating the high voltage. In this study, flyback method is used to generate high voltage on plasma electrolytic oxidation (PEO) application. PEO is a process that combine electrochemical oxidation process and high voltage spark. This application needs high voltage to produce plasma. The plasma is used to form a new surface coating on metal. Flyback circuit is succesfully simulated on LTSpice IV. Voltage value and waveform on simulation has been observed and compared with the real one. The measured and observed part is IGB gate, output voltage of transformer before diode, and load voltage after diode. Flyback effect and waveform on simulation has the similiar result with the real one. A 10 volt input voltage can produce output voltage on the average of 1 kilovolt. Therefore, flyback simulation is able to represent flyback ability on real circuit for generating high voltage which can be used on high voltage generation for PEO application.Intisari-Metode flyback merupakan salah satu metode pembangkitan tegangan tinggi dengan sumber tegangan rendah. Metode ini memiliki rangkaian yang sederhana. Rangkaian flyback hanya memiliki dua komponen utama untuk membangkitkan tegangan tinggi. Pada makalah ini, digunakan metode flyback untuk merancang pembangkitan tegangan tinggi pada aplikasi plasma electrolytic oxidation (PEO). PEO merupakan suatu proses kombinasi dari sebuah proses oksidasi elektrokimia dan penerapan percikan (spark) tegangan tinggi. Aplikasi PEO membutuhkan tegangan tinggi untuk menghasilkan plasma. Plasma pada proses tersebut digunakan untuk membentuk lapisan permukaan baru pada sebuah permukaan metal. Rangkaian flyback yang disimulasikan dengan LTSpice IV berhasil dilakukan. Nilai tegangan dan bentuk geombang pada simulasi telah diamati dan dibandingkan dengan pengujian rangkaian flyback yang dibuat. Tiga titik yang diukur dan diamati pada simulasi dan pengujian adalah tegangan pada gate IGBT, tegangan keluaran transformator sebelum diode, dan tegangan pada beban setelah diode. Efek flyback yang terjadi dan bentuk gelombang yang dihasilkan simulasi mendekati hasil pengujian. Dengan sumber tegangan pulsa 10 volt, rangkaian ini menghasilkan tegangan keluaran rata-rata 1 kilovolt. Dengan demikian, simulasi flyback mampu merepresentasikan kemampuan rangkaian flyback yang telah dibuat untuk menghasilkan tegangan tinggi, sehingga metode flyback dapat digunakan pada pembangkitan tegangan tinggi untuk aplikasi PEO.Kata Kunci-flyback, tegangan tinggi, plasma, plasma elecrolytic oxidation, PEO.I. PENDAHULUAN Pada umumnya, pembangkitan tegangan tinggi dilakukan dengan rangkaian yang berukuran besar dan rumit. Seiring berkembangnya penelitian tentang pengaplikasian tegangan tinggi di segala bidang saat ini, dibutuhkan rangkaian yang lebih sederhana untuk dapat membangkitkan tegangan tinggi. Rangkaian yang lebih sederhana dapat memudahkan penelitian di la...
Wind energy and solar energy are the prime energy sources which are being utilized for renewal energy. The performance of a photovoltaic (PV) array for solar energy is affected by temperature, irradiation, shading, and array configuration. Often, the PV arrays are shadowed, completely or partially, by the passing clouds, neighboring buildings and towers, trees, and utility and telephone poles. Under partially shaded conditions, the PV characteristics are more complex with multiple peaks, hence, it is very important to understand and predict the MPP under PSC in order to extract the maximum possible power. This paper presents the development of PV array simulator for studying the I–V and P–V characteristics of a PV array under a partial shading condition. It can also be used for developing and evaluating new maximum power point tracking techniques, for PV array with partially shaded conditions. It is observed that, for a given number of PV modules, the array configuration significantly affects the maximum available power under partially shaded conditions. This is another aspect to which the developed tool can be applied. The model has been experimentally validated and the usefulness of this research is highlighted with the help of several illustrations.
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