Nowadays, SMS spam has been overflowing in many countries. In fact, the standards of filtering SMS spam are different from country to country. However, the current technologies and researches about ...SMS spam filtering all focus on dividing SMS message into two classes: legitimate and illegitimate. It does not conform to the actual situation and need. Furthermore, they are facing several difficulties, such as: (1) High quality and large-scale SMS spam corpus is very scarce, fine categorized SMS spam corpus is even none at all. This seriously handicaps the researchers’ studies. (2) The limited length of SMS messages lead to lack of enough features. These factors seriously degrade the performance of the traditional classifiers (such as SVM, K-NN, and Bayes). In this paper, we present a new fine categorized SMS spam corpus which is unique and the largest one as far as we know. In addition, we propose a classifier, which is based on the probability topic model. The classifier can alleviate feature sparse problem in the task of SMS spam filtering. Moreover, we compare the approach with three typical classifiers on the new SMS spam corpus. The experimental results show that the proposed approach is more effective for the task of SMS spam filtering.
Nowadays, SMS spam has been overflowing in many countries. In fact, the standards of filtering SMS spam are different from country to country. However, the current technologies and researches about ...SMS spam filtering all focus on dividing SMS message into two classes: legitimate and illegitimate. It does not conform to the actual situation and need. Furthermore, they are facing several difficulties, such as: (1) High quality and large-scale SMS spam corpus is very scarce, fine categorized SMS spam corpus is even none at all. This seriously handicaps the researchers' studies. (2) The limited length of SMS messages lead to lack of enough features. These factors seriously degrade the performance of the traditional classifiers (such as SVM, K-NN, and Bayes). In this paper, we present a new fine categorized SMS spam corpus which is unique and the largest one as far as we know. In addition, we propose a classifier, which is based on the probability topic model. The classifier can alleviate feature sparse problem in the task of SMS spam filtering. Moreover, we compare the approach with three typical classifiers on the new SMS spam corpus. The experimental results show that the proposed approach is more effective for the task of SMS spam filtering. Keywords: Spam SMS corpus, Topic Model, LDA, SMTM
Silver-modified TiO2 microspheres (SMTMs) have been synthesized via a novel in-situ Ag-loading method in which tetrabutyl titanate (TBOT) is hydrolyzed in a mixed solution of ethanol and AgNO3. The ...structures, compositions and optical properties of the as-prepared products were characterized by XRD, FT-IR, EDX, XPS, FESEM, HRTEM and UV–vis diffuse reflectance techniques, and the photocatalytic properties of the product was estimated for the photodegradation of rhodamine B (Rh B) under visible light irradiation. The photo-response of the as-obtained SMTMs is greatly shifted into the visible light spectrum, and exhibits a band gap narrowing compared with that of pure TiO2 microspheres (PT). The photocatalytic tests of SMTMs reveal a much higher photocurrent and photocatalytic activity than that of other composites and PT. However, the photocatalytic activities of SMTMs in aqueous suspension depend on the Ag-loading process. The product synthesized by using, for example, an in-situ Ag-loading process not only showed an enhanced visible light-driven photocatalytic activity, but also displayed good photocatalytic stability.
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•In-situ Ag-loading is a potential technique for obtaining the silver-modified TiO2.•The photocatalytic activity of the products on degradation of Rh B was evaluated.•The SMTMs show the highest photocatalytic activity under visible light irradiation.
Silver-modified TiO2 microspheres (SMTMs) have been synthesized via a facile in-situ Ag-loading method that controlled hydrolysis of tetrabutyltitanate (TBOT) in a mixed solution of ethanol and ...AgNO3. The physical and chemical properties of SMTMs were studied by SEM, XRD, XPS (X-ray photoelectron spectroscopy) and UV–vis diffuse reflectance spectra (DRS). The state of silver species was measured by the XPS technique. The photocatalytic activity of the SMTMs was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The experimental results showed that the SMTMs exhibited a much better photocatalytic activity than that of PT (pure TiO2) and P25 (commercial TiO2).
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•In-situ Ag-loading method is a potential technique for the fabrication of the SMTMs.•The photocatalytic activities of the products on the removing of Rh B were evaluated.•The SMTMs showed the highest photocatalytic activity under visible light irradiation.
