Judul: Pengembangan stemmer berbasis kamus besar bahasa Indonesia
Abstrak: Although many studies have aimed to develop a stemmer for Indonesian language, there are still some issues that these studies have not been able to overcame, for example an issue concerning morphophonemic. Kamus Besar Bahasa Indonesia-Based Stemmer is a stemmer which can be used as one of the main components in an information retrieval system for documents written in Indonesian. The use of Kamus Besar Bahasa Indonesia (KBBI) as a base for stemming allows the stemmer to produce the appropriate stem according to Indonesian rule of forming derived words. All words contained in KBBI are compiled in a database and used as a reference in the stemming process. For every word that is going to be stemmed, a group of words that may be present in KBBI is formed. This group of words is formed by removing parts of word that may be known as affixes in Indonesian language. This research also conducts an analysis of Ridha Stemmer, which has been widely used by many information retrieval researches at IPB’s Computer Science Department. The analysis is limited only on the correctness of the produced stems. Both stemmers are evaluated by measuring the recall-precision values returned by the use of each stemmer in an information retrieval system. The analysis shows that Ridha Stemmer yields correct stems at 20.15% of total tokens, and 25.56% wrong stems. From the result of performance evaluation, it is obtained that the use of KBBI-Based Stemmer gives slightly higher average precision value than Ridha Stemmer, with values each 0.441 and 0.443. Keywords:
Keyword: information retrieval, stemmer, Kamus Besar Bahasa Indonesia

Judul: Sistem Pencarian Turunan Kata pada Al-Quran Menggunakan Light Stemming dan Clustering untuk Pembicara Bahasa Indonesia
Abstrak: Topics searching in the Holy Quran using word derivative is difficult task without arabic word morphology knowledge. Light stemming is stem extraction method that can replaces word derivative plays in topics searching. However, this method fail to removes infix so clustering method can be better hopefully. This research aims to build word derivative searching system using light stemming and clustering that appropriate with Indonesian speaker’s query. There are two types of query that accepted by the system that have 30 queries in each: Latin and Arabic script. Searching quality evaluation using Average Precision (AVP), Mean Average Precision (MAP), and Precision at N shows that light stemming is better than clustering with 0.30 AVP in light stemming and 0.03 AVP in clustering. Whereas for running time, light stemming is four time faster than clustering at Arabic script.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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