Click-through information is considered as a valuable source of users＇ implicit relevance feedback. As user behavior is usually influenced by a number of factors such as position, presentation style and site reputati...Click-through information is considered as a valuable source of users＇ implicit relevance feedback. As user behavior is usually influenced by a number of factors such as position, presentation style and site reputation, researchers have proposed a variety of assumptions to generate a reasonable estimation of result relevance. Therefore, many click models have been proposed to describe how user click action happens and to predict click probability （and search result relevance）. This work builds upon many years of existing efforts from THUIR labs, summarizes the most recent advances and provides a series of practical click models. In this paper, we give an introduction of how to build an effective click model. We use two click models as specific examples to introduce the general procedures of building a click model. We also introduce common evaluation metrics for the comparison of different click models. Some useful datasets and tools are also introduced to help readers better understand and implement existing click models. The goal of this survey is to bring together current efforts in the area, summarize the research performed so far and give a view on building click models for web search.展开更多
The new reality of smart distribution systems with use of generation sources of small and medium sizes brings new challenges for the operation of these systems. The complexity and the large number of nodes requires us...The new reality of smart distribution systems with use of generation sources of small and medium sizes brings new challenges for the operation of these systems. The complexity and the large number of nodes requires use of methods which can reduce the processing time of algorithms such as power flow, allowing its use in real time. This paper presents a known methodology for calculating the power flow in three phases using backward/forward sweep method, and also considering other network elements such as voltage regulators, shunt capacitors and sources of dispersed generation of types PV （active power and voltage） and PQ （active and reactive power）. After that, new elements are introduced that allow the parallelization of this algorithm and an adequate distribution of work between the available processors. The algorithm was implemented using a multi-tiered architecture; the processing times were measured in many network configurations and compared with the same algorithm in the serial version.展开更多
This paper investigates the usage of passive harmonic filters to mitigate harmonic distortions when two resonant points are present in a system caused by shunt capacitors used for power factor correction and bus volta...This paper investigates the usage of passive harmonic filters to mitigate harmonic distortions when two resonant points are present in a system caused by shunt capacitors used for power factor correction and bus voltage regulation. Six scenarios were investigated using DIgSILENT 14 power factor）＇ software. The investigations are with and without power factor correction and capacitors used to increase bus voltage. Passive harmonic filters are designed to reduce harmonic distortions at the PCC （point of common coupling） to fall within the IEEE 519 harmonic voltage and current limits caused by parallel resonance. The results of the case studies are analysed to evaluate the effectiveness of the filter design.展开更多
The author considers the hyperbolic geometric flow introduced by Kong and Liu. Using the techniques and ideas to deal with the evolution equations along the Ricci flow by Brendle, the author derives the global forms...The author considers the hyperbolic geometric flow introduced by Kong and Liu. Using the techniques and ideas to deal with the evolution equations along the Ricci flow by Brendle, the author derives the global forms of evolution equations for Levi-Civita connection and curvature tensors under the hyperbolic geometric flow. In addition, similarly to the Ricci flow case, it is shown that any solution to tile hyperbolic geometric flow that develops a singularity in finite time has unbounded Ricci curvature.展开更多
文摘Click-through information is considered as a valuable source of users＇ implicit relevance feedback. As user behavior is usually influenced by a number of factors such as position, presentation style and site reputation, researchers have proposed a variety of assumptions to generate a reasonable estimation of result relevance. Therefore, many click models have been proposed to describe how user click action happens and to predict click probability （and search result relevance）. This work builds upon many years of existing efforts from THUIR labs, summarizes the most recent advances and provides a series of practical click models. In this paper, we give an introduction of how to build an effective click model. We use two click models as specific examples to introduce the general procedures of building a click model. We also introduce common evaluation metrics for the comparison of different click models. Some useful datasets and tools are also introduced to help readers better understand and implement existing click models. The goal of this survey is to bring together current efforts in the area, summarize the research performed so far and give a view on building click models for web search.
文摘The new reality of smart distribution systems with use of generation sources of small and medium sizes brings new challenges for the operation of these systems. The complexity and the large number of nodes requires use of methods which can reduce the processing time of algorithms such as power flow, allowing its use in real time. This paper presents a known methodology for calculating the power flow in three phases using backward/forward sweep method, and also considering other network elements such as voltage regulators, shunt capacitors and sources of dispersed generation of types PV （active power and voltage） and PQ （active and reactive power）. After that, new elements are introduced that allow the parallelization of this algorithm and an adequate distribution of work between the available processors. The algorithm was implemented using a multi-tiered architecture; the processing times were measured in many network configurations and compared with the same algorithm in the serial version.
文摘This paper investigates the usage of passive harmonic filters to mitigate harmonic distortions when two resonant points are present in a system caused by shunt capacitors used for power factor correction and bus voltage regulation. Six scenarios were investigated using DIgSILENT 14 power factor）＇ software. The investigations are with and without power factor correction and capacitors used to increase bus voltage. Passive harmonic filters are designed to reduce harmonic distortions at the PCC （point of common coupling） to fall within the IEEE 519 harmonic voltage and current limits caused by parallel resonance. The results of the case studies are analysed to evaluate the effectiveness of the filter design.
文摘The author considers the hyperbolic geometric flow introduced by Kong and Liu. Using the techniques and ideas to deal with the evolution equations along the Ricci flow by Brendle, the author derives the global forms of evolution equations for Levi-Civita connection and curvature tensors under the hyperbolic geometric flow. In addition, similarly to the Ricci flow case, it is shown that any solution to tile hyperbolic geometric flow that develops a singularity in finite time has unbounded Ricci curvature.
