A Two-stage Multilevel Randomized Response Technique With Proportional Odds Models and Missing Covariates

2020 ◽  
pp. 004912412091495
Author(s):  
Shu-Hui Hsieh ◽  
Shen-Ming Lee ◽  
Chin-Shang Li
Keyword(s):  
Missing At Random ◽  
Missing Covariates ◽  
Randomized Response ◽  
Personal Privacy ◽  
Proportional Odds ◽  
Two Stage ◽  
Inverse Probability ◽  
Wide Range ◽  
Proportional Odds Models ◽  
Income Data

Surveys of income are complicated by the sensitive nature of the topic. The problem researchers face is how to encourage participants to respond and to provide truthful responses in surveys. To correct biases induced by nonresponse or underreporting, we propose a two-stage multilevel randomized response (MRR) technique to investigate the true level of income and to protect personal privacy. For a wide range of applications, we present a proportional odds model for two-stage MRR data and apply inverse probability weighting and multiple imputation methods to deal with covariates on some subjects that are missing at random. A simulation study is conducted to investigate the effects of missing covariates and to evaluate the performance of the proposed methods. The practicality of the proposed methods is illustrated with the regular monthly income data collected in the Taiwan Social Change Survey. Furthermore, we provide an estimate of personal regular monthly mean income.

scholarly journals Object Detection in Very High-Resolution Aerial Images Using One-Stage Densely Connected Feature Pyramid Network

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3341 ◽  
Author(s):  
Hilal Tayara ◽  
Kil Chong
Keyword(s):  
High Resolution ◽  
Object Detection ◽  
Computation Time ◽  
Aerial Images ◽  
Feature Maps ◽  
Two Stage ◽  
One Stage ◽  
Wide Range ◽  
Feature Pyramid ◽  
Very High

Object detection in very high-resolution (VHR) aerial images is an essential step for a wide range of applications such as military applications, urban planning, and environmental management. Still, it is a challenging task due to the different scales and appearances of the objects. On the other hand, object detection task in VHR aerial images has improved remarkably in recent years due to the achieved advances in convolution neural networks (CNN). Most of the proposed methods depend on a two-stage approach, namely: a region proposal stage and a classification stage such as Faster R-CNN. Even though two-stage approaches outperform the traditional methods, their optimization is not easy and they are not suitable for real-time applications. In this paper, a uniform one-stage model for object detection in VHR aerial images has been proposed. In order to tackle the challenge of different scales, a densely connected feature pyramid network has been proposed by which high-level multi-scale semantic feature maps with high-quality information are prepared for object detection. This work has been evaluated on two publicly available datasets and outperformed the current state-of-the-art results on both in terms of mean average precision (mAP) and computation time.

scholarly journals Light echoes from the plateau in Eta Carinae’s Great Eruption reveal a two-stage shock-powered event

2018 ◽  
Vol 480 (2) ◽  
pp. 1466-1498 ◽  
Author(s):  
Nathan Smith ◽  
Jennifer E Andrews ◽  
Armin Rest ◽  
Federica B Bianco ◽  
Jose L Prieto ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Binary Interaction ◽  
Shock Interaction ◽  
Spectral Evolution ◽  
Two Stage ◽  
Circumstellar Material ◽  
Broad Emission ◽  
Wide Range ◽  
Light Echoes ◽  
Η Car

ABSTRACT We present multi-epoch photometry and spectroscopy of a light echo from η Carinae’s 19th century Great Eruption. This echo's light curve shows a steady decline over a decade, sampling the 1850s plateau of the eruption. Spectra show the bulk outflow speed increasing from ∼150 km s−1 at early times, up to ∼600 km s−1 in the plateau. Later phases also develop remarkably broad emission wings indicating mass accelerated to more than  10 000 km s−1. Together with other clues, this provides direct evidence for an explosive ejection. This is accompanied by a transition from a narrow absorption line spectrum to emission lines, often with broad or asymmetric P Cygni profiles. These changes imply that the pre-1845 luminosity spikes are distinct from the 1850s plateau. The key reason for this change may be that shock interaction with circumstellar material (CSM) dominates the plateau. The spectral evolution of η Car closely resembles that of the decade-long eruption of UGC 2773-OT, which had clear signatures of shock interaction. We propose a two-stage scenario for η Car’s eruption: (1) a slow outflow in the decades before the eruption, probably driven by binary interaction that produced a dense equatorial outflow, followed by (2) explosive energy injection that drove CSM interaction, powering the plateau and sweeping slower CSM into a fast shell that became the Homunculus. We discuss how this sequence could arise from a stellar merger in a triple system, leaving behind the eccentric binary seen today. This gives a self-consistent scenario that may explain interacting transients across a wide range of initial mass.

Sign in / Sign up

Export Citation Format

Share Document