380 research outputs found
Steganography for Invisible Communication: A Review
No full textSteganography is the science and art of embedding secret messages in innocuous looking carriers in such a way that it does not draw the attention of anyone other than the sender and the targeted recipient, thus a method for secret and invisible communication which provides security through obscurity. Its main purpose is to hide the occurrence of communication over a public channel. Steganography has been used since ancient times and has grown exponentially in the recent past because of the improvements in computing power. Earlier, steganography was implemented using some physical medium i.e. some tangible objects but now a days, it is implemented electronically by using several other intangible objects i.e. data can be hidden using any type of media, be it image in bmp, jpeg, gif format or some music file, video clip, text file, SMS etc. In this paper, different types of techniques used to hide data have been discussed with major focus on image based modern steg-anographic techniques
Ancillary investigations in uveitis
No full textAncillary investigations are the backbone of uveitis work-up both for anterior and posterior segment diseases. They help in making the diagnosis, ruling out certain differential diagnosis and monitoring inflammation during the follow-up. This review aims to be an overview describing the role of commonly used investigations for uveitis
Autonomous Mobility on-Demand in urban areas: A Rotterdam-Zuid case study
No full textDue to connectivity problems, the attractiveness of public transport is limited. Policymakers aim to increase the modal share of public transport to protect the accessibility, livability, safety, sustainability and efficiency in the cities of the future. Applying Autonomous Mobility on-Demand (AMoD) systems as a feeder service for public transport hubs can improve the first- and last-mile trip leg, increasing the attractivity of public transport. It is essential for the implementation of AMoD systems to predict the impacts of varying operational strategies on beforehand. From an operators perspective, especially the financial viability of AMoD operations is vital and yet unclear. An existing gravity-based travel demand estimation model built in OmniTRANS is used to predict the AMoD passenger demand. Besides, an agent-based simulation model is developed using the software Anylogic that is connected to the demand-model as an add-on module to simulate the behavior of passengers and AMoD vehicles within an urban environment. The agent-based simulation model is applied to the case study Rotterdam-Zuid, where Station Zuidplein and Station Lombardijen function as an AMoD hub. The simulation outputs show that activating dynamic ridesharing using wireless fast chargers at the stations results in the most financially viable operation. Activating automatic relocation results in the most costly operation. Compared to existing public transport services, carsharing systems and taxi systems, the AMoD system shows to save a large amount of expenses due to the absence of drivers.STADCivil Engineering | Transport and Plannin
Modeling Urban Automated Mobility on-Demand Systems: an Agent-Based Approach
No full textAutomated Mobility-on-Demand (AMoD) systems are expected to revolutionize urban mobility systems. However, there are uncertainties in the planning and operations of AMoD systems. We deem the agent-based approach as being well suited for modeling new phenomena in future AMoD systems and therefore shed some light on the uncertainties about the operation and the impacts of such systems. Recommendations to various stakeholders are provided through the different contributions.Mathematical Physic
Assessing the Potential of the Strategic Formation of Urban Platoons for Shared Automated Vehicle Fleets
No full textThis paper addresses the problem of studying the impacts of the strategic formation of platoons in automated mobility-on-demand (AMoD) systems in future cities. Forming platoons has the potential to improve traffic efficiency, resulting in reduced travel times and energy consumption. However, in the platoon formation phase, coordinating the vehicles at formation locations for forming a platoon may delay travelers. In order to assess these effects, an agent-based model has been developed to simulate an urban AMoD system in which vehicles travel between service points transporting passengers either forming or not forming platoons. A simulation study was performed on the road network of the city of The Hague, Netherlands, to assess the impact on traveling and energy usage by the strategic formation of platoons. Results show that forming platoons could save up to 9.6% of the system-wide energy consumption for the most efficient car model. However, this effect can vary significantly with the vehicle types and strategies used to form platoons. Findings suggest that, on average, forming platoons reduces the travel times for travelers even if they experience delays while waiting for a platoon to be formed. However, delays lead to longer travel times for the travelers with the platoon leaders, similar to what people experience while traveling in highly congested networks when platoon formation does not happen. Moreover, the platoon delay increases as the volume of AMoD requests decreases; in the case of an AMoD system serving only 20% of the commuter trips (by private cars in the case-study city), the average platoon delays experienced by these trips increase by 25%. We conclude that it is beneficial to form platoons to achieve energy and travel efficiency goals when the volume of AMoD requests is high.Mathematical PhysicsTransport and Plannin
Spectral domain optical coherence tomography predates fluorescein angiography in diagnosing central serous chorioretinopathy
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