Video events recognition is a challenging task for high-level understanding of video se- quence. At present, there are two major limitations in existing methods for events recognition. One is that no algorithms are av...Video events recognition is a challenging task for high-level understanding of video se- quence. At present, there are two major limitations in existing methods for events recognition. One is that no algorithms are available to recognize events which happen alternately. The other is that the temporal relationship between atomic actions is not fully utilized. Aiming at these problems, an algo- rithm based on an extended stochastic context-free grammar （SCFG） representation is proposed for events recognition. Events are modeled by a series of atomic actions and represented by an extended SCFG. The extended SCFG can express the hierarchical structure of the events and the temporal re- lationship between the atomic actions. In comparison with previous work, the main contributions of this paper are as follows： ① Events （include alternating events） can be recognized by an improved stochastic parsing and shortest path finding algorithm. ② The algorithm can disambiguate the detec- tion results of atomic actions by event context. Experimental results show that the proposed algo- rithm can recognize events accurately and most atomic action detection errors can be corrected sim- ultaneously.展开更多
根据2009—2012年南太平洋长鳍金枪鱼（Thunnus alalunga）延绳钓生产统计数据及遥感获取的海表温度（sea surface temperature,SST）、叶绿素a浓度（chlorophyll a concentration,Chl-a）和海面高度距平（sea surface height anomaly,S...根据2009—2012年南太平洋长鳍金枪鱼（Thunnus alalunga）延绳钓生产统计数据及遥感获取的海表温度（sea surface temperature,SST）、叶绿素a浓度（chlorophyll a concentration,Chl-a）和海面高度距平（sea surface height anomaly,SSHA）等环境数据,分析了长鳍金枪鱼单位捕捞努力量渔获量（catch per unit of fishing effort,CPUE）的时空分布及其与环境因子的相关性。结果表明：长鳍金枪鱼作业渔场主要集中在4°S—28°S、158°E—176°E附近海域;长鳍金枪鱼渔场CPUE呈明显的季节性变化,1—3月CPUE值较低（〈12.5尾·千钩-1）,随后逐渐增加,至7月达到最大值为18.1尾·千钩-1,而8—12月基本呈逐渐降低趋势;1月渔场重心位于16°S、168°E附近海域,2—3月向西北偏移,而在3—7月逐渐向东南方向转移,8月以后开始逐渐回撤至西北方向,在9—12月渔场重心变化幅度相对较小,主要位于15°S—16°S、168°E—169°E海域;总体来说,长鳍金枪鱼中心渔场最适SST为27.0～30.5℃,次适SST为20～24℃;最适叶绿素a浓度为0.02～0.08mg·m-3,最适海面高度距平为3～23 cm。展开更多
基金Supported by the National Natural Science Foundation of China(60805028,60903146)Natural Science Foundation of Shandong Province of China (ZR2010FM027)+1 种基金SDUST Research Fund(2010KYTD101)China Postdoctoral Science Foundation(2012M521336)
文摘Video events recognition is a challenging task for high-level understanding of video se- quence. At present, there are two major limitations in existing methods for events recognition. One is that no algorithms are available to recognize events which happen alternately. The other is that the temporal relationship between atomic actions is not fully utilized. Aiming at these problems, an algo- rithm based on an extended stochastic context-free grammar （SCFG） representation is proposed for events recognition. Events are modeled by a series of atomic actions and represented by an extended SCFG. The extended SCFG can express the hierarchical structure of the events and the temporal re- lationship between the atomic actions. In comparison with previous work, the main contributions of this paper are as follows： ① Events （include alternating events） can be recognized by an improved stochastic parsing and shortest path finding algorithm. ② The algorithm can disambiguate the detec- tion results of atomic actions by event context. Experimental results show that the proposed algo- rithm can recognize events accurately and most atomic action detection errors can be corrected sim- ultaneously.
文摘根据2009—2012年南太平洋长鳍金枪鱼（Thunnus alalunga）延绳钓生产统计数据及遥感获取的海表温度（sea surface temperature,SST）、叶绿素a浓度（chlorophyll a concentration,Chl-a）和海面高度距平（sea surface height anomaly,SSHA）等环境数据,分析了长鳍金枪鱼单位捕捞努力量渔获量（catch per unit of fishing effort,CPUE）的时空分布及其与环境因子的相关性。结果表明：长鳍金枪鱼作业渔场主要集中在4°S—28°S、158°E—176°E附近海域;长鳍金枪鱼渔场CPUE呈明显的季节性变化,1—3月CPUE值较低（〈12.5尾·千钩-1）,随后逐渐增加,至7月达到最大值为18.1尾·千钩-1,而8—12月基本呈逐渐降低趋势;1月渔场重心位于16°S、168°E附近海域,2—3月向西北偏移,而在3—7月逐渐向东南方向转移,8月以后开始逐渐回撤至西北方向,在9—12月渔场重心变化幅度相对较小,主要位于15°S—16°S、168°E—169°E海域;总体来说,长鳍金枪鱼中心渔场最适SST为27.0～30.5℃,次适SST为20～24℃;最适叶绿素a浓度为0.02～0.08mg·m-3,最适海面高度距平为3～23 cm。
