Topic
Filter factor
About: Filter factor is a research topic. Over the lifetime, 401 publications have been published within this topic receiving 3018 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this article, the role of forests in filtering airborne organic pollutants from the atmosphere and transferring them to soil was examined, and a mathematical model was assembled to calculate the filter factor, defined as the quotient of the net deposition of a given compound to a forest and its net deposition to a bare soil.
Abstract: The role of forests in filtering airborne organic pollutants from the atmosphere and transferring them to soil was examined. A mathematical model was assembled to calculate the filter factor, defined as the quotient of the net deposition of a given compound to a forest and its net deposition to a bare soil. A simple equation was obtained that expressed the filter factor as a function of just two physical-chemical properties of the chemical: the octanol/air and air/water partition coefficients (KOA and KAW). The model was then applied to a spruce and to a beech/oak canopy close to Bayreuth for which measured deposition velocities were available. The model simulations indicated that there was little filter effect for volatile compounds with log KOA < 7 and for hydrophilic substances with log KAW < −6. Similarly, although forest canopies are thought to be effective filters of airborne particles, the filter factor for compounds that are primarily particle bound was also close to 1, since the dry particle bou...
233 citations
7 Aug 2002
TL;DR: In this paper, the authors discuss the importance of model-based design methods, treating the derivative filter as an inherent part of the design, and illustrate how default choices for the derivative filters may lead to excessive control actions.
Abstract: A PID controller is a second-order controller, and as such involves four parameters. However, many available tuning methods design only three parameters, and then use a default choice for the derivative filter factor. In this paper it is pointed out that for a PID controller of series form a default value for the derivative filter makes some sense, since it corresponds to a lead-lag controller. For PID controllers of ideal (or parallel) form default values are much less natural. The main purpose of the paper is to discuss the importance of model-based design methods, treating the derivative filter as an inherent part of the design. For example, it is illustrated how default choices for the derivative filter may lead to excessive control actions.
139 citations
15 Mar 1999
TL;DR: An improved structure is introduced in order to visualize subband outputs of the directional filter Banks, while retaining the attractive properties of the original directional filter banks such as 1-D separable filtering, perfect reconstruction, and maximal decimation.
Abstract: A new directional filter bank for image analysis and classification is proposed. This paper introduces an improved structure in order to visualize subband outputs of the directional filter banks, while retaining the attractive properties of the original directional filter banks such as 1-D separable filtering, perfect reconstruction, and maximal decimation. Using this structure, any arbitrary 2/sup n/ band directional filter bank can be implemented by cascading simple directional filter bank blocks, unlike the original structure that needs a parallel structure for visualizing subband outputs. Also, in order to have nondistorted phase information in the subbands for visualization, both FIR and IIR filter prototypes that can be implemented efficiently are provided for linear phase filtering. This paper shows the approach proposed here can be applied to image analysis and classification.
80 citations
TL;DR: In this article, a hybrid silicon photonic integrated filter is proposed and demonstrated with a novel structure, which incorporates a ring resonator in one arm of a Mach-Zehnder interferometer making it possible to obtain a programmable filter response.
Abstract: A hybrid silicon photonic integrated filter is proposed and demonstrated with a novel structure. This filter incorporates a ring resonator in one arm of a Mach-Zehnder interferometer making it possible to obtain a programmable filter response. The optical filter consists of a 5-mm-long delay loop made of low-loss silicon waveguides with integrated thermal modulators resulting in a 0.164-nm free spectral range with absolute phase tunability and gain elements that allow for the tuning of the filter factor. The microwave response of this integrated filter is measured and display tunability of 20 GHz.
77 citations
Patent•
26 Jun 2003
TL;DR: A moving picture encoding device includes an inter-pixel filter (114) having a filter A (114a), filter B (114b), filter C (114c), and filter D (114d) each having different filtering intensity for filtering decoded image data and removing block distortion which is a high frequency noise in the vicinity of the boundary between blocks, and a filter processing control section (110) for deciding the filtering intensity of the interpixel filter as mentioned in this paper.
Abstract: A moving picture encoding device includes an inter-pixel filter (114) having a filter A (114a), a filter B (114b), a filter C (114c), and a filter D (114d) each having different filtering intensity for filtering decoded image data and removing block distortion which is a high frequency noise in the vicinity of the boundary between blocks, and a filter processing control section (110) for deciding the filtering intensity of the inter-pixel filter (114).
69 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 4 |
| 2017 | 8 |
| 2016 | 7 |