Lower Bounds for Shoreline Searching With 2 or More Robots

Searching for a line on the plane with $n$ unit speed robots is a classic online problem that dates back to the 50's, and for which competitive ratio upper bounds are known for every $n\geq 1$. In this work we improve the best lower bound known for $n=2$ robots from 1.5993 to 3. Moreover we prove that the competitive ratio is at least $\sqrt{3}$ for $n=3$ robots, and at least $1/\cos(\pi/n)$ for $n\geq 4$ robots. Our lower bounds match the best upper bounds known for $n\geq 4$, hence resolving these cases. To the best of our knowledge, these are the first lower bounds proven for the cases $n\geq 3$ of this several decades old problem.Comment: This is an updated version of the paper with the same title which will appear in the proceedings of the 23rd International Conference on Principles of Distributed Systems (OPODIS 2019) Neuchatel, Switzerland, July 17-19, 201

Analyzing the Impact of Spatio-Temporal Sensor Resolution on Player Experience in Augmented Reality Games

Along with automating everyday tasks of human life, smartphones have become one of the most popular devices to play video games on due to their interactivity. Smartphones are embedded with various sensors which enhance their ability to adopt new new interaction techniques for video games. These integrated sen- sors, such as motion sensors or location sensors, make the device able to adopt new interaction techniques that enhance usability. However, despite their mobility and embedded sensor capacity, smartphones are limited in processing power and display area compared to desktop computer consoles. When it comes to evaluat- ing Player Experience (PX), players might not have as compelling an experience because the rich graphics environments that a desktop computer can provide are absent on a smartphone. A plausible alternative in this regard can be substituting the virtual game world with a real world game board, perceived through the device camera by rendering the digital artifacts over the camera view. This technology is widely known as Augmented Reality (AR). Smartphone sensors (e.g. GPS, accelerometer, gyro-meter, compass) have enhanced the capability for deploying Augmented Reality technology. AR has been applied to a large number of smartphone games including shooters, casual games, or puzzles. Because AR play environments are viewed through the camera, rendering the digital artifacts consistently and accurately is crucial because the digital characters need to move with respect to sensed orientation, then the accelerometer and gyroscope need to provide su ciently accurate and precise readings to make the game playable. In particular, determining the pose of the camera in space is vital as the appropriate angle to view the rendered digital characters are determined by the pose of the camera. This defines how well the players will be able interact with the digital game characters. Depending in the Quality of Service (QoS) of these sensors, the Player Experience (PX) may vary as the rendering of digital characters are affected by noisy sensors causing a loss of registration. Confronting such problem while developing AR games is di cult in general as it requires creating wide variety of game types, narratives, input modalities as well as user-testing. Moreover, current AR games developers do not have any specific guidelines for developing AR games, and concrete guidelines outlining the tradeoffs between QoS and PX for different genres and interaction techniques are required. My dissertation provides a complete view (a taxonomy) of the spatio-temporal sensor resolution depen- dency of the existing AR games. Four user experiments have been conducted and one experiment is proposed to validate the taxonomy and demonstrate the differential impact of sensor noise on gameplay of different genres of AR games in different aspect of PX. This analysis is performed in the context of a novel instru- mentation technology, which allows the controlled manipulation of QoS on position and orientation sensors. The experimental outcome demonstrated how the QoS of input sensor noise impacts the PX differently while playing AR game of different genre and the key elements creating this differential impact are - the input modality, narrative and game mechanics. Later, concrete guidelines are derived to regulate the sensor QoS as complete set of instructions to develop different genres or AR games

A Citizen's Guide to Redistricting

Provides a detailed overview of states' rules and processes for redrawing federal, state, and local legislative districts. Illustrates possible motives behind redistricting, effects on elections, implications for legislation, and reform recommendations

Remote Controlled Restraint: The Effect of Remote Warfighting Technology on Crisis Escalation

How do technologies that remove warfighters from the front lines affect the frequency and intensity of military confrontations between states? Many scholars and policymakers fear that weapons that reduce the risks and costs of war – in blood and treasure – will lead states to resort to force more frequently during crises, destabilizing the international security environment. These concerns have featured prominently in debates surrounding the proliferation and use of remote warfighting technologies, such as drones. This project sets out to evaluate whether and how drones affect crisis escalation. Specifically, do drones allow decisionmakers to deploy military forces more frequently during interstate crises? Once deployed, how do these systems affect escalation dynamics? I argue that drones can help control escalation, raising questions about scholarly theories that suggest the world is more dangerous and less stable when technology makes conflict cheaper and less risky. At the core of this project is a theory of technology-enabled escalation control. The central argument is that technologies like drones that remove friendly forces from the battlefield may lead states to use force more frequently, but decrease the likelihood of escalation when used in lieu of inhabited platforms. More specifically, these technologies lower the political barriers to initiating military operations during crises, primarily by eliminating the risk of friendly force casualties and the associated domestic political consequences for launching military operations. At the same time, removing personnel from harm’s way may reduce demand for escalatory reprisals after remotely operated systems are lost to hostile action. Drones can also help to mitigate escalatory spirals by collecting intelligence that overcomes information asymmetries that often contribute to armed conflict, helping facilitate more measured decision-making and tailored targeting of enemy forces. By more fully considering how technology affects escalatory dynamics after the initial use of force, technology-enabled escalation control theory advances our understanding of the link between technology and conflict. I test the theory using a multi-method approach that combines case studies with original experiments embedded in surveys fielded on public and military samples. The dissertation also introduces a new research method for international relations research: experimental manipulations embedded in wargames with military participants. In Chapter 1 and 2, I define the concept of crisis escalation and review the literature that examines the effect of technology on escalation and conflict dynamics. I then introduce the theory of technology-enabled escalation control and outline four mechanisms that undergird the theory – increased initiation, tempered/tailored targeting, restrained retaliation, and amplified aggression. Each of these hypothesized mechanisms describes ways in which emerging technologies can prevent crises from escalating into broader or more intense conflicts. Chapter 3 describes each component of the multi-method research design that I use to test the theory in Chapters 4 through 7. Chapter 4 uses experiments embedded in surveys and wargames to assess whether and how drones allow states to more frequently initiate military operations. Chapter 5 tests whether drones enable decisionmakers to control escalation by restraining retaliation after attacks on a state’s drones. Chapter 6 and 7 test the theory in the context of U.S drone use during the Cold War and Israeli drone use from the 1960s through late-2010s. The findings of these empirical tests provide strong support for technology-enabled escalation control. In Chapter 8, I conclude with a summary of the analysis and test the generalizability of the theory beyond the state use of drones. I find that tenets of technology-enabled escalation control explain escalation dynamics associated with U.S. cyber operations against North Korea and Hezbollah’s use of drones against Israel and during the Syrian Civil War. The chapter also maps out pathways for future research and identifies policy implications. My findings suggest the growing proliferation of drones will increase the frequency of military confrontations during crises, yet these confrontations are unlikely to escalate. Even though drones may help control escalation, clearer doctrine, rules of engagement, and international agreements to govern their use will help to further avoid crisis escalation and conflict