Browsing by Author "Saha, Abir"

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    Determine characteristics requirement for the surrogate road edge objects for road departure mitigation testing
    (2019) Chien, Stanley; Yi, Qiang; Lin, Jun; Saha, Abir; Li, Lin; Chen, Yaobin; Chen, Chi-Chih; Sherony, Rini; Electrical and Computer Engineering, School of Engineering and Technology
    Road departure mitigation system (RDMS), a vehicle active safety feature, uses road edge objects to determine potential road departure. In the U.S., 45%, 16%, and 15% of car-mile (traffic flow * miles) roads have grass, metal guardrail, and concrete divider as road edge, respectively. It is difficult to test RDMS with real roadside objects. Lightweight and crashable surrogate roadside objects that have representative radar, LIDAR and camera characteristics of real objects have been developed for testing. This paper describes the identification of automotive radar, LIDAR, and visual characteristics of metal guardrail, concrete divider, and grass. These characteristics will be referenced for designing and fabricating the representative surrogate objects for RDMS testing. Colors and types of the roadside objects were identified from 24,735 randomly sampled locations in the US using Google street view images. The radar and LIDAR parameters were measured using 24GHz/77GHz radar and 350-2500nm IR spectrometer.
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    Development of infrared reflectance characteristics of surrogate roadside objects
    (2018-08) Saha, Abir; Chien, Stanley; Li, Lingxi; Li, Lin
    An important topic in autonomous vehicle related research in recent times is road departure warning (RDW) and road keeping assistance (RKA). RDW or RKA should be able to recognize and avoid roadside objects. Standard tests are needed to evaluate the performance of RDW and RKA feature of cars from different manufacturers. To avoid damage to the cars under test and the test environment during testing, there is a need of soft, durable and reusable surrogate targets representing various real roadside objects such as curb, concrete divider and metal guardrail. These surrogate objects should have representative characteristics of real roadside objects from the point of view of various commonly used object detection sensors on the vehicles such as camera, radar and LIDAR. Transportation Active Safety Institute (TASI) at Indian University-Purdue University Indianapolis (IUPUI) is in the process of developing surrogate concrete divider, curb metal guardrail and grass that should be recognized as real roadside objects by LIDAR sensors, can be crashed without damage to the test vehicle and can be reused even after multiple crashes. The first step is to understand what the representative roadside objects should look like from the point of view of LIDAR units using laser of various wavelengths, and the next step is to design surrogate objects that successfully emulate the properties of the real roadside objects. Reflectance of an object is an important property for LIDAR detection. This thesis describes an approach for the determination of infrared reflectance property of concrete, metal guardrail and grass for different LIDAR view angles. Various samples of each of these roadside objects were evaluated. Based on these measurements, the suggested reflectance of surrogate roadside objects in the common LIDAR wavelength range of 800-1100 nm is specified. Finally, the design of surrogate roadside objects that satisfy these requirements is described, and the infrared reflectance of these surrogate objects are compared to the suggested reflectance bounds for different LIDAR view angles.
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    Development of Surrogate Grass for the Evaluation of Vehicle Road Departure Mitigation Systems
    (IEEE, 2020-09) Chien, Stanley; Zhou, Jue; Yi, Qiang; Pandey, Seeta Ram; Saha, Abir; Lin, Jun; Chen, Yaobin; Sherony, Rini; Electrical and Computer Engineering, School of Engineering and Technology
    Vehicle road departure mitigation system (RDMS), as new active safety technology, has been introduced into the market in recent years. This system can detect roadside objects and road edges to reduce the risk of roadway departure crashes. To evaluate and improve the performance of RDMS, surrogates of roadside objects, which have the same camera, radar, and LiDAR characteristics of the real objects, need to be developed. Grass is the most common road edge in the U.S. as seen from the real road data. This paper describes the development of surrogate grass. The LiDAR (infrared) and radar characteristics of the selected artificial turf (grass) are obtained and compared with those of real grass. In order to make the surrogate grass match the real grass in the view of sensors (LiDAR, radar and camera), a special color coating with high reflectance material is applied to the artificial turf. Both LiDAR and radar measurements confirmed that the surrogate grass closely match the key characteristics of the real grass. Five grass colors and eighteen color patterns were identified based on 1,021 grass road-edge samples from all states of the U.S. 300-meter long surrogate grass was made and successfully used on the test track for the vehicle RDMS evaluation.
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    Impact of Social Networking Sites on Post-Partum Depression in Women: An Analysis in the Context of Bangladesh
    (IEEE, 2017-12) Saha, Abir; Das, Maitraye; Electrical and Computer Engineering, School of Engineering and Technology
    Postpartum Depression (PPD) refers to moderate or severe depression in a woman after childbirth. It is strikingly common in new mothers from all regions of the world with a prevalence of around 10-15%. PPD can have severe adverse effects on maternal and child health, such as suicidal tendency of the mother, infanticide as well as poor cognitive and developmental growth of the child. Despite this, few women seek medical attention due to ignorance, negligence and financial limitations; the latter is especially true for those who live in developing countries. Nowadays, social networking sites (SNS) e.g., Facebook can act as accessible and effective tools for the prevention and treatment of PPD. In this paper, we analyze the opinions and awareness level of Bangladeshi people about PPD and impact of using SNS during postpartum period on reducing PPD based on our survey (N = 93). We also discuss possible SNS-based interventions and design implications that can effectively and feasibly reduce PPD in women in developing countries.