Letter Interactions in Brief Visual Displays

1980 ◽  
Vol 32 (4) ◽  
pp. 649-668 ◽  
Author(s):  
Grover C. Gilmore
Keyword(s):  
Target Letter ◽  
Target Detection ◽  
Detection Performance ◽  
Visual Displays ◽  
Low Level ◽  
Feature Similarity ◽  
Feature Information ◽  
Inhibitory Potential ◽  
The One

Three experiments were conducted to examine the influence of non-target letters on target detection performance. It was hypothesised that letters which are similar would exert a stronger masking influence on each other than letters which have a low level of feature similarity. The results indicate, however, that every letter has the same inhibitory potential regardless of its similarity rating to other letters. The highly significant letter interactions which did occur in the study were interpreted as evidence for an additive, rather than a subtractive, influence by the non-targets. It is proposed that when a target has an ambiguous identity, due to an impoverished representation, it may be disambiguated by the addition of feature information from the immediate letter context. The effect of filling in the target representation with a feature value from a non-target letter will be to weight the final representation towards the target which has the value most similar to the one substituted. In a sense, then, non-targets which are similar to a target can actually enhance target detection scores.

scholarly journals Implementation of a Modified Faster R-CNN for Target Detection Technology of Coastal Defense Radar

2021 ◽  
Vol 13 (9) ◽  
pp. 1703
Author(s):  
He Yan ◽  
Chao Chen ◽  
Guodong Jin ◽  
Jindong Zhang ◽  
Xudong Wang ◽  
...  
Keyword(s):  
False Alarm ◽  
False Alarm Rate ◽  
Target Detection ◽  
Real Data ◽  
Detection Performance ◽  
Detection Accuracy ◽  
Constant False Alarm Rate ◽  
Data Set ◽  
Detection Technology ◽  
Coastal Defense

The traditional method of constant false-alarm rate detection is based on the assumption of an echo statistical model. The target recognition accuracy rate and the high false-alarm rate under the background of sea clutter and other interferences are very low. Therefore, computer vision technology is widely discussed to improve the detection performance. However, the majority of studies have focused on the synthetic aperture radar because of its high resolution. For the defense radar, the detection performance is not satisfactory because of its low resolution. To this end, we herein propose a novel target detection method for the coastal defense radar based on faster region-based convolutional neural network (Faster R-CNN). The main processing steps are as follows: (1) the Faster R-CNN is selected as the sea-surface target detector because of its high target detection accuracy; (2) a modified Faster R-CNN based on the characteristics of sparsity and small target size in the data set is employed; and (3) soft non-maximum suppression is exploited to eliminate the possible overlapped detection boxes. Furthermore, detailed comparative experiments based on a real data set of coastal defense radar are performed. The mean average precision of the proposed method is improved by 10.86% compared with that of the original Faster R-CNN.

scholarly journals Clutter Cancellation and Long Time Integration for GNSS-Based Passive Bistatic Radar

2021 ◽  
Vol 13 (4) ◽  
pp. 701 ◽  
Author(s):  
Binbin Wang ◽  
Hao Cha ◽  
Zibo Zhou ◽  
Bin Tian
Keyword(s):  
Fourier Transform ◽  
Target Detection ◽  
Time Integration ◽  
Detection Performance ◽  
Bistatic Radar ◽  
Detection Range ◽  
Robust Detection ◽  
Coherent Integration ◽  
Long Time ◽  
Long Time Integration

Clutter cancellation and long time integration are two vital steps for global navigation satellite system (GNSS)-based bistatic radar target detection. The former eliminates the influence of direct and multipath signals on the target detection performance, and the latter improves the radar detection range. In this paper, the extensive cancellation algorithm (ECA), which projects the surveillance channel signal in the subspace orthogonal to the clutter subspace, is first applied in GNSS-based bistatic radar. As a result, the clutter has been removed from the surveillance channel effectively. For long time integration, a modified version of the Fourier transform (FT), called long-time integration Fourier transform (LIFT), is proposed to obtain a high coherent processing gain. Relative acceleration (RA) is defined to describe the Doppler variation results from the motion of the target and long integration time. With the estimated RA, the Doppler frequency shift compensation is carried out in the LIFT. This method achieves a better and robust detection performance when comparing with the traditional coherent integration method. The simulation results demonstrate the effectiveness and advantages of the proposed processing method.

scholarly journals Fast Implementation of Insect Multi-Target Detection Based on Multimodal Optimization

2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Rui Wang ◽  
Yiming Zhang ◽  
Weiming Tian ◽  
Jiong Cai ◽  
Cheng Hu ◽  
...  
Keyword(s):  
Target Detection ◽  
Computational Cost ◽  
Detection Performance ◽  
Coherent Detection ◽  
Observation Data ◽  
Multimodal Optimization ◽  
Performance Simulation ◽  
Single Target ◽  
Parameter Search ◽  
Long Time

Entomological radars are important for scientific research of insect migration and early warning of migratory pests. However, insects are hard to detect because of their tiny size and highly maneuvering trajectory. Generalized Radon–Fourier transform (GRFT) has been proposed for effective weak maneuvering target detection by long-time coherent detection via jointly motion parameter search, but the heavy computational burden makes it impractical in real signal processing. Particle swarm optimization (PSO) has been used to achieve GRFT detection by fast heuristic parameter search, but it suffers from obvious detection probability loss and is only suitable for single target detection. In this paper, we convert the realization of GRFT into a multimodal optimization problem for insect multi-target detection. A novel niching method without radius parameter is proposed to detect unevenly distributed insect targets. Species reset and boundary constraint strategy are used to improve the detection performance. Simulation analyses of detection performance and computational cost are given to prove the effectiveness of the proposed method. Furthermore, real observation data acquired from a Ku-band entomological radar is used to test this method. The results show that it has better performance on detected target amount and track continuity in insect multi-target detection.

scholarly journals Robust Weighted l1,2 Norm Filtering in Passive Radar Systems

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3270 ◽  
Author(s):  
Baris Satar ◽  
Gokhan Soysal ◽  
Xue Jiang ◽  
Murat Efe ◽  
Thiagalingam Kirubarajan
Keyword(s):  
Target Detection ◽  
Impulsive Noise ◽  
Simulated Data ◽  
Real Data ◽  
Detection Performance ◽  
Passive Radar ◽  
Mobile Telecommunication ◽  
Telecommunication System ◽  
Conventional Methods ◽  
Non Gaussian

Conventional methods such as matched filtering, fractional lower order statistics cross ambiguity function, and recent methods such as compressed sensing and track-before-detect are used for target detection by passive radars. Target detection using these algorithms usually assumes that the background noise is Gaussian. However, non-Gaussian impulsive noise is inherent in real world radar problems. In this paper, a new optimization based algorithm that uses weighted l 1 and l 2 norms is proposed as an alternative to the existing algorithms whose performance degrades in the presence of impulsive noise. To determine the weights of these norms, the parameter that quantifies the impulsiveness level of the noise is estimated. In the proposed algorithm, the aim is to increase the target detection performance of a universal mobile telecommunication system (UMTS) based passive radars by facilitating higher resolution with better suppression of the sidelobes in both range and Doppler. The results obtained from both simulated data with α stable distribution, and real data recorded by a UMTS based passive radar platform are presented to demonstrate the superiority of the proposed algorithm. The results show that the proposed algorithm provides more robust and accurate detection performance for noise models with different impulsiveness levels compared to the conventional methods.

scholarly journals Gambaran Derajat Grit Pada Mahasiswa Akademi Keperawatan “X” di Kabupaten Kepulauan Aru

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Roseilla Nora Izaach
Keyword(s):  
Socioeconomic Status ◽  
Life Goals ◽  
Personality Factors ◽  
Measuring Instrument ◽  
Descriptive Data ◽  
Low Level ◽  
Validity Coefficient ◽  
Future Success ◽  
The One ◽  
High Level

This study aimed to describe the level of grit in the Nursing Academy student X in the Aru Islands. Grit is the one of the latest theory in the study of Positive Psychology which emphasizes of two important aspects are perseverance of efforts and consistency of interest, that determines the success of individuals in achieving their life goals. The goal of achieving future success through education is the reason this research is conducted. Respondents in this study were students in 2014. The number of respondents are 51 people with entirely female. Measuring instrument used in this study was grit scale consists of 12 items with reliability of 0.85 and a validity coefficient range  from 0.44 to 0.82 ( Duckworth, et.al.,2007) . Based on the results of the processing of descriptive data, it was found that the majority of respondents have a low level of grit with percentage of 86.3%. Variable aspect of grit perseverance of efforts, the majority of respondents have a low level of 90.2%, and the consistency aspect of interest, the majority of respondents have a high level of 66.7%. The socioeconomic status of the students is based on the type of work of the parents, not indicating the tendency to be related to the degree of grit. Further research that can be done is to investigate more deeply about the contribution of personality factors, differences in cultural background and demographics that affect grit. Keywords: Grit, socioeconomic status, demographics

Of Baby Bottles and Bisphenol A: Debates about the Safety of an Endocrine Disruptor

2014 ◽  
Author(s):  
Sarah A. Vogel
Keyword(s):  
Bisphenol A ◽  
Behavioral Problems ◽  
Snack Food ◽  
Political Debate ◽  
Low Level ◽  
Department Of Health ◽  
The Simpsons ◽  
Baby Bottles ◽  
Growing Body ◽  
The One

In a 2009 episode of The Simpsons, Marge Simpson baked what she considered the ultimate healthy, socially conscious, safe snack food: “home­made, organic, nongluten, fairtrade zucchini cupcakes.” Proudly presenting the cupcakes to her daughter’s playgroup, Marge was asked what kind of butter she’d used. “None!” she exclaimed; she had baked the cupcakes in a nonstick pan. But Marge’s beaming pride quickly dissolved into embarrassment when she learned of her apparent eco-stupidity. Marge didn’t know that nonstick pans were made with PFOA (perflurooctanoic acid). “There is only one thing more dangerous than PFOAs, Marge,” one mother declared. “Plastics made with BPAs. Never, ever let your child near any product with the number 7.” At that moment, a child tips a cup up to his mouth revealing the number 7 on the bottom of the cup. The mothers scream in unison and run hysterically out of the house. Bisphenol A (or BPA) had become a three-letter household word. The chemical, used for over a half-century in plastics, was now at the center of a contentious scientific and political debate as well as fodder for prime-time cultural satire. Was BPA safe? On the one hand, a growing number of researchers, championed by environmental and health advocates, point to a growing body of research suggestive of serious health risks of BPA. This includes animal research on low-level effects of BPA exposure on prostate and mammary gland development and neurobehavioral function and development; a small but growing body of epidemiological research on BPA exposures and cardio­vascular disease, diabetes, and social behavioral problems; and evidence of widespread, low-level human exposure including in pregnant women (vom Saal et al. 2007; U.S. Department of Health and Human Services 2008). On the other hand, the Food and Drug Administration (FDA) and its counterpart in Europe, the European Food Safety Authority, maintain that the levels in food are low enough to be considered safe for all humans.

“A Particularly Serious Crime”

2021 ◽  
pp. 158-184
Author(s):  
Elliott Young
Keyword(s):  
United States ◽  
Home Country ◽  
The United States ◽  
The Other ◽  
President Obama ◽  
Felony Conviction ◽  
Low Level ◽  
Serious Crime ◽  
The One ◽  
Radical Shift

Machado was just five years old in 1990 when she was brought to the United States by her mother, who was desperate to escape the civil war raging in their home country of El Salvador; she wanted a better life for her two young daughters. In 2015, she was picked up in a traffic stop in Arkansas which triggered her deportation based on a felony conviction from a decade earlier. Machado’s story reveals a radical shift that had been happening since the mid-1990s. Unprecedented numbers of immigrants were being caught in a system that penalized people with mandatory deportations for relatively low-level crimes. Machado does not fit easily into the Manichean distinction made by President Obama in 2014 between “felons” on the one hand and “families” on the other. Machado, like so many others, is both.

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