Judul: Temporal Entity Tagging untuk Dokumen Bahasa Indonesia
Abstrak: One of the processes in document pre-processing is providing identifier tags called Named Entity Tagging. This research aims to implement a temporal entity tagging in Indonesian language documents with rule-based method. Temporal expressions are marked with DATE tag and the temporal value of the expression. Temporal expression comprise explicit expression, implicit expression, and event expression. The rules were obtained by analyzing temporal expressions in 100 Indonesian documents. There are 40 derived rules implemented in this system over 341 temporal expressions in the document. The system could find all of the temporal expressions consisting of 150 explicit temporal expressions, 155 implicit temporal expressions, and 36 event expressions. Also, the evaluation was conducted on 34 other documents. The system can correctly identify as many as 122 of 129 temporal expression contained in the additional documents. The system has achieved an accuracy of 100% for the 100 initial documents and 94.57% for the 34 test documents. Thus, rule-based identification of temporal entities for Indonesian performs well.
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Judul: Temporal Question Answering System Bahasa Indonesia
Abstrak: Time is an important dimension in information retrieval. Temporal expressions describe time information embedded in the documents. Therefore, extraction and normalization of temporal expressions from documents are crucial. In this research, a question answering system is implemented for temporal information processing from documents in Indonesian language based on four types of temporal question beginning with question words such as siapa (what), kapan (when), di mana (where), and berapa (how many). Implicit time references in document are first normalized and tagged manually into explicit time references. Complex temporal question is divided into simpler questions by using temporal signal detection for specific sequence of events. In order to obtain answer candidates, heuristic weighting is performed on the top passages. Answer extraction is performed using the smallest distance between query and answer candidates. A corpus containing 100 documents and 80 queries is used in this research. Answer evaluation is based on three criteria, namely, Right, Wrong, and Unsupported. The questions are used to evaluate the results of BM25 and Proximity ranking modes. The evaluation for simple temporal questions (Type 1 and 2) using BM25 and Proximity gave the same results at 85% Right answers for Type 1 and 75% for Type 2. The results for complex temporal questions (Type 3 and 4) indicated good performance. The best results were obtained by BM25 at 95% Right answers for Type 3 and 75% for Type 4, while using Proximity resulted in 85% Right answers for Type 3 and 80% for Type 4. We also used our corpus on a nontemporal question answering system by Umriadi in 2011. The results are 60%, 55%, 60%, and 40% Right answers for Type 1, 2, 3, and 4, respectively, much lower than our temporal question answering system. Therefore, temporal expression extraction and temporal signal identification are particularly important for handling questions containing temporal information. Our system is able to identify and answer the temporal questions in Indonesian language.
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Judul: Bioelectricity Production from Citrobacter freundii GBH253 and Chlorella pyrenoidosa on Microbial Fuel Cell Anode with Different Carbon Sources
Abstrak: Microbial Fuel Cell (MFC) development has significantly increased from various aspects to get higher and more stable electricity. Developing MFC on microorganism aspect is very important because it plays a crucial role in the MFC system. C. freundii GBH253 is one of the potential exoelectrogen bacterium that could be developed for the MFC system. Integrating C. freundii GBH253 and electricity-producing microalgae, such as C. pyrenoidosa, in the anode of MFC could get more stable and higher electricity. In this study, C. freundii GBH253 and C. pyrenoidosa were coupled to produce electricity from different substrates. C. freundii GBH253 and C. pyrenoidosa were tested on three different media types before being tested on MFC. They were also examined for the co-cultivation test to determine the symbiotic relationship between the two microorganisms. The MFC test was conducted using the Randomized Block Design Factorial and the Tukey test to see significant differences from each treatment. The parameters observed in this study were voltage, power density, Chemical Oxygen Demand (COD), Coulombic Efficiency (CE), pH, and volatile fatty acid (VFA). C. freundii GBH253 cannot grow on microalgae medium, while C. pyrenoidosa could grow on bacterial medium and a mixture of bacterium and microalgae media. The bacterium gained benefit from co-culture with microalgae. In the MFC test, electricity was generated in all treatments, which bacterium + microalgae with acetate treatment could generate power density up to 211,97 mW/m2 and the most stable compared to others. Production of electricity in bacterium-microalgae combination dominated by the bacterium; hence, microalgae still help bacterium by producing electricity and raised the COD value. The pH value of all treatments was higher than the initial pH. Acetate and phenol were VFA produced in all treatments, whereas butyric acid and propionic acid were found in some treatments. Pearson correlation showed that some VFA highly correlated with power density.
Keyword: Chlorella pyrenoidosa, Substrate, Microbial Fuel Cell, Electricity Producing Microalgae, Volatile Fatty Acid, Citrobacter freundii