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Simple Semantics in Topic Detection and Tracking 总被引:3,自引:0,他引:3
Topic Detection and Tracking (TDT) is a research initiative that aims at techniques to organize news documents in terms of news events. We propose a method that incorporates simple semantics into TDT by splitting the term space into groups of terms that have the meaning of the same type. Such a group can be associated with an external ontology. This ontology is used to determine the similarity of two terms in the given group. We extract proper names, locations, temporal expressions and normal terms into distinct sub-vectors of the document representation. Measuring the similarity of two documents is conducted by comparing a pair of their corresponding sub-vectors at a time. We use a simple perceptron to optimize the relative emphasis of each semantic class in the tracking and detection decisions. The results suggest that the spatial and the temporal similarity measures need to be improved. Especially the vagueness of spatial and temporal terms needs to be addressed. 相似文献
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This paper examines the exploitation of inertial measurements to analyze javelin throwing mechanics. The main objective was to demonstrate that consumer-grade inertial navigation systems, augmented with some position and attitude data obtained from a video sequence, yield detailed information of the mechanics of javelin throwing. Especially, such a system makes it possible to analyze the momentary force and power exerted on the javelin during the acceleration phase. Although the presented system is a pilot, leaving space for further improvements, it already reveals the potential of inertial navigation systems to sports. In practise, an inertial measurement unit was embedded inside the tip of the javelin to determine the javelin’s momentary attitude, position, and velocity. Graphs on the speed and angular velocity about the longitudinal axis of the javelin during the whole performance are presented. The maximum estimated release speed and release angular speed were 28.02 m/s and 215.9 rad/s, respectively. The acceleration phase trajectory of the javelin and its deviation from a straight line path are demonstrated. Additionally, the momentary forces and powers are shown and the effect of aerodynamic forces on the projectile is specified. The magnitude of the maximum tangential forces and accelerating powers were 364 N and 9.76 kW. The duration and length of the acceleration phase trajectory varied between 223 and 231 ms, and 2.48 and 2.75 m. To estimate the accuracy of the inertial measurements, the acceleration phase results were compared to measurements made with high-speed cameras. 相似文献
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Juha Kettunen 《Assessment & Evaluation in Higher Education》2004,29(3):357-368
The study analyses the role of regional development in higher education using the approach of the balanced scorecard, which provides a framework for organizations to describe and communicate their strategy. It turns out that the balanced scorecard is not only an approach for implementing the strategy, but it also provides a general framework for evaluating the strategy from the different perspectives. The study presents examples where the new evaluation approach has been used to analyse the national educational policy of regional development, regional strategies of higher education institutions and their cooperation. According to the results of the study, cooperation between higher education institutions is most important from the perspectives of learning and regional development. 相似文献
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This study identifies the responsibilities of the bodies and institutions involved in the implementation of the Bologna Process.
They include the levels of Europe, nations, higher education institutions, departments, degree programmes, teachers and students.
The future planning is analysed using the Balanced Scorecard approach designed for the communication and implementation of
the strategy. The approach is used to analyse the objectives of European education policy from the different perspectives.
Strategic planning and quality assurance are most efficient when they are transformed into action at the closest possible
point to teaching and learning. 相似文献
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Runlong Cai Rujing Yin Chao Yan Dongsen Yang Chenjuan Deng Lubna Dada Juha Kangasluoma Jenni Kontkanen Roope Halonen Yan Ma Xiuhui Zhang Pauli Paasonen Tuukka Petj Veli-Matti Kerminen Yongchun Liu Federico Bianchi Jun Zheng Lin Wang Jiming Hao James N Smith Neil M Donahue Markku Kulmala Douglas R Worsnop Jingkun Jiang 《国家科学评论(英文版)》2022,9(10)
Transformation of low-volatility gaseous precursors to new particles affects aerosol number concentration, cloud formation and hence the climate. The clustering of acid and base molecules is a major mechanism driving fast nucleation and initial growth of new particles in the atmosphere. However, the acid–base cluster composition, measured using state-of-the-art mass spectrometers, cannot explain the measured high formation rate of new particles. Here we present strong evidence for the existence of base molecules such as amines in the smallest atmospheric sulfuric acid clusters prior to their detection by mass spectrometers. We demonstrate that forming (H2SO4)1(amine)1 is the rate-limiting step in atmospheric H2SO4-amine nucleation and the uptake of (H2SO4)1(amine)1 is a major pathway for the initial growth of H2SO4 clusters. The proposed mechanism is very consistent with measured new particle formation in urban Beijing, in which dimethylamine is the key base for H2SO4 nucleation while other bases such as ammonia may contribute to the growth of larger clusters. Our findings further underline the fact that strong amines, even at low concentrations and when undetected in the smallest clusters, can be crucial to particle formation in the planetary boundary layer. 相似文献
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Juha Himanka 《Higher Education》2015,69(1):117-128
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In research literature, two study orientations have been identified: meaning orientation and reproducing orientation. Few studies have examined how study orientations and conceptions of knowledge (epistemologies) interrelate. Further, longitudinal studies of the development of orientations and of conceptions of knowledge in relation to academic achievement are scarce. The study set out:(i) to examine the relationship between study orientations and conceptions of knowledge; (ii) to investigate how these kinds of beliefs change during short, career-aimed studies of natural science; (iii) to explore how study orientations and changes in them are related to study success. The sample consisted of 66 undergraduate students of pharmacy studying at a Finnish university. Participants filled in a questionnaire regarding study orientations and conceptions of knowledge at the beginning of their studies and after 3 years of study. Results showed a relationship between reproducing orientation and dualist conceptions of knowledge. Reproducing orientation and dualism diminished during undergraduate natural science studies. Further, students' reproducing orientation after the last study year was negatively related to their study success. In addition, a favourable development was detected in the group of above-average achievers, who maintained their initial level of meaning orientation while diminishing their level of reproducing orientation. Implications for instruction are discussed. 相似文献