Multi-Wavelength Photometric and Polarimetric Observations of the Outburst of 3C 454.3 in Dec. 2009

In December 2009, the bright blazar, 3C 454.3 exhibited a strong outburst in the optical, X-ray and gamma-ray regions. We performed photometric and polarimetric monitoring of this outburst in the optical and near-infrared bands with TRISPEC and HOWPol attached to the Kanata telescope. We also observed this outburst in the infrared band with AKARI, and the radio band with the 32-m radio telescope of Yamaguchi University. The object was in an active state from JD 2455055 to 2455159. It was 1.3 mag brighter than its quiescent state before JD 2455055 in the optical band. After the end of the active state in JD 2455159, a prominent outburst was observed in all wavelengths. The outburst continued for two months. Our optical and nearinfrared polarimetric observations revealed that the position angle of the polarization (PA) apparently rotated clockwise by 240 degrees within 11 d in the active state (JD 2455063-2455074), and after this rotation, PA remained almost constant during our monitoring. In the outburst state, PA smoothly rotated counterclockwise by 350 degrees within 35 d (JD 2455157-2455192). Thus, we detected two distinct rotation events of polarization vector in opposite directions. We discuss these two events compared with the past rotation events observed in 2005, 2007 and 2008.Comment: 9 pages, 6 figures, accepted for publication in PAS

Enhancement of aggregation-induced emission by introducing multiple o-carborane substitutions into triphenylamine

The enhancement of aggregation-induced emission (AIE) is presented on the basis of the strategy for improving solid-state luminescence by employing multiple o-carborane substituents. We synthesized the modified triphenylamines with various numbers of o-carborane units and compared their optical properties. From the optical measurements, the emission bands from the twisted intramolecular charge transfer (TICT) state were obtained from the modified triphenylamines. It was notable that emission efficiencies of the multi-substituted triphenylamines including two or three o-carborane units were enhanced 6- to 8-fold compared to those of the mono-substituted triphenylamine. According to mechanistic studies, it was proposed that the single o-carborane substitution can load the AIE property via the TICT mechanism. It was revealed that the additional o-carborane units contribute to improving solid-state emission by suppressing aggregation-caused quenching (ACQ). Subsequently, intense AIEs were obtained. This paper presents a new role of the o-carborane substituent in the enhancement of AIEs

A Ranking Method based on User's Contexts for Information Recommendation

ICUIMC '08 : the 2nd international conference on Ubiquitous information management and communication,January 31 - February 01,2008,Suwon,KoreaWe propose a ranking method using a Support Vector Machine for information recommendation. By using the SVM, a recommendation method can determine suitable items for a user from enormous item sets. However, it can decide based on just two classes: whether the user likes a thing or not. When there is a large number of recommended items, it is not easy for the user to find the best item by herself. To resolve this issue, it is desirable to rank the items based on the user's preferences. Moreover, the user's preferences change depending on the context. Based on the above problem, we propose a context-aware ranking method for information recommendation. Our method considers a user's context when ranking items. Our method consists of the following two steps: (1) Predicting important feature parameters for the user. (2) Calculating a ranking score of each item in recommendation candidates. In this paper, we describe our method and show experimental results

A Recommendation Method Considering User'sTime Series Contexts

ICUIMC '09: the 3nd international conference on Ubiquitous information management and communication,January 15 - 16,2008,Suwon,KoreaThis paper proposes a recommendation method considering users' time series contexts which are situations that have occurred / will occur in the past/future. There are some recommendation methods that provide information suitable for users' action patterns as the recommendation methods considering them. These methods provide information referring to the other users that have a similar action pattern to that of an active user. However, since a user's action pattern changes depending on the user's contexts, the methods need to refer to the other users' action patterns related to the current user's contexts. In this paper, we propose a recommendation method considering the user's time series contexts considering that the user's action pattern changes depending on the user's contexts