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...

Fabry-Pérot (FP) filter arrays fabricated by highresolution three dimensional (3D) NanoImprint technology are presented. A fabrication process to implement 3D templates with very high vertical resolution is developed. Filter arrays with 64 different cavity heights have been fabricated requiring only one single imprint step. Different optical methods are involved in this paper to characterize geometric and spectral properties. In order to investigate the transfer accuracy of the surface quality from the NanoImprint template to the filter, we use white light interferometry (WLI) measurements. Surface roughness and structure height accuracy of <1 nm for both values demonstrate the conservation of these critical parameters during the 3D NanoImprint process. Additionally, an optical characterization methodology for spectral transmission and reflection measurements of the filter arrays is introduced and applied. A compact microscope spectrometer setup which allows efficient handling, high resolution and short inspection time is verified by comparing measurement results to that of an optical bench setup used as a reference. First, this paper focuses on the foundation of the FP filter arrays, second on the technological fabrication, third on validation calibration of the setup and forth on the characterization of the filter arrays. The measurements envisage the spectral position of filter transmission lines, the full width at half maximum (FWHM) and the

Recently the switching mode used in a buck converter is controlled by pulse width modulation (PWM) which has relatively higher efficiency compared to a linear power supply system. In general, there are two problems that often occur in the buck converter, First, the difficulties in controlling inductor current which has considerably large ripple, and second, a transient output voltage that appears at the start-up. By using fuzzy logic control in PWM switching mode, the inductor current and output voltage of the buck converter can be controlled. Using Mamdani method fuzzy logic with 2 inputs, i.e. Error and Change of Error, the system produces 1 output, which is duty ratio. The results showed that the fuzzy logic control decreased the error of the output voltage of buck converter by 3%, and decreased the ripple in the inductor current by 1.5% up to 3%. Intisari-Pada masa sekarang ini buck converter banyak yang menggunakan mode switching dengan pengaturan menggunakan pulse width modulation (PWM) yang memiliki efisiensi yang lebih tinggi dibanding sistem catu daya linier. Secara umum ada dua permasalahan yang sering terjadi pada buck converter. Pertama, sulitnya pengendalian arus pada induktor yang memiliki ripple yang cukup besar. Kedua adalah transient tegangan keluaran yang muncul pada saat start up. Dengan menggunakan fuzzy logic control sebagai pengendali PWM, maka pengaturan arus pada induktor dan tegangan keluaran buck konverter dapat dibuat sesuai dengan keinginan. Fuzzy logic menggunakan metode mamdani dengan 2 input yaitu Error, Perubahan Error, dan 1 output berupa duty ratio. Dari uji coba yang telah dilakukan, didapatkan hasil output tegangan memiliki error yang berkurang pada kurang lebih 3% jika ditambahkan dengan pengendalian fuzzy logic, dan pengaturan arus pada induktor lebih baik yaitu berkurangnya ripple sebesar 1,5% sampi 3%.

The microstrip antenna has small, lightweight shape characteristics, and limit performances. It is necessary to increase the performances, especially the axial ratio (Ar) of the previous antenna configured in two layers accompanying the capacitive coupling between them. If length of feeding line and width-to-length ratio of radiating patch are not matched, it can decrease the Ar performance. This paper discusses about the analysis of previous antenna (two layers) and modified antenna (one layer), optimized modified antenna using stub on coplanar-fed both single and array microstrip patch antenna for mobile satellite communication, especially for receiver antenna, Rx. The Method of Moment (MoM) is used to analyze the antenna with an infinite ground plane and substrate. The antenna is made of a thin patch conductor and a microstrip-line. The microstrip-line is located on the same layer which has the thickness h = 1.6 mm and uses a conventional substrate (relative permittivity, ε r = 2.17 and loss tangent, δ = 0.0009). The patch conductor is fed by a coplanar-fed with microstrip-line to obtain a conformal configuration. The dual-fed type is to generate a left-handed circular polarization (LHCP) which is combined with an equilateral triangle patch. In this case, one of the microstrip-line feeds is set longer than the other to introduce a 90 0 phase delay. Moreover, the simulation results discuss about the three varies size of stub embedded on coplanar-fed and compare among of them to confirm that the antenna satisfy the target. The results of single antenna using stub-fed, especially for bandwidth of axial ratio below 3-dB and gain above 5 dBic are about 0.02 GHz and 0.065 GHz, respectively. The results of array antenna, in the case of bandwidth of axial ratio below 3-dB and gain above 5 dBic are about 0.03 GHz and 0.3 GHz, respectively. In addition, the result for axial ratio of the modified antenna and the previous antenna at 2.5025 GHz are 0.27 dB and 1.02 dB, respectively. It is caused a coplanar-fed which connected directly to the radiating patch (one layer antenna).

Sparse code multiple access (SCMA), which combines the advantages of low density signature (LDS) and code-division multiple access (CDMA), is regarded as one of the promising modulation technique candidate for the next generation of wireless systems. Conventionally, the message passing algorithm (MPA) is used for data detector at the receiver side. However, the MPA-SCMA cannot be implemented in the next generation wireless systems, because of its unacceptable complexity cost. Specifically, the complexity of MPA-SCMA grows exponentially with the number of antennas. Considering the use of high dimensional systems in the next generation of wireless systems, such as massive multi-user MIMO systems, the conventional MPA-SCMA is prohibitive. In this paper, we propose a low complexity detector algorithm named the expectation propagation algorithm (EPA) for SCMA. Mainly, the EPA-SCMA solves the complexity problem of MPA-SCMA and enables the implementation of SCMA in massive MU-MIMO systems. For instance, the EPA-SCMA also enables the implemantation of SCMA in the next generation wireless systems. We further show that the EPA can achieve the optimal detection performance as the numbers of transmit and receive antennas grow. We also demonstrate that a rotation design in SCMA codebook is unnecessary, which is quite rather different from the general assumption.