Dimitris Papanikolaou | Harvard University (original) (raw)

Uploads

Papers by Dimitris Papanikolaou

Cities have become more networked and wired, thus generating unprecedented amounts of operational... more Cities have become more networked and wired, thus generating unprecedented amounts of operational and behavioral data. For instance, a city’s traffic is instrumented by online mapping services (Google maps) in conjunction with crowd-sourcing (Waze). In this work, we present an Urban Analytics Platform (UAP) that demonstrates a systematic framework to tackle data-driven problems that the modern urban settings present. UAP embodies an end-to-end system for ingesting multiple data sources and processing them via neural network models to tackle predictive urban computing problems, like traffic flow. Results show improved traffic flow prediction and how we can utilize the improved prediction to inform on the possible weather conditions for abnormal traffic patterns.

Proceedings of the 26th International Conference on Education and Research in Computer Aided Architectural Design in Europe (eCAADe)

Adjunct Proceedings of the 2019 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2019 ACM International Symposium on Wearable Computers, 2019

We often perceive other peoples' presence implicitly, through the traces of their interaction... more We often perceive other peoples' presence implicitly, through the traces of their interactions with physical objects. What if our urban environments could mediate these traces allowing remotely located people perceive each other's presence collectively? We developed Pneuxels, a network of programmable inflatables, placed at remote sites, that allow visitors in one site to perceive the presence of visitors in other sites, promoting thereby a sense of collective awareness and place-making. Pneuxels (Pneumatic Pixels) are pneumatically actuated pixels, connected through a web-socket platform, that change their physical state based on input from other Pneuxels, from the environment, or from users. We discuss our experiences in designing, prototyping, and testing Pneuxels, and we report our results from preliminary user studies.

Annual Simulation Symposium, Apr 3, 2011

One-way vehicle sharing systems are convenient mobility systems consisting of parking stations an... more One-way vehicle sharing systems are convenient mobility systems consisting of parking stations and a fleet of shared vehicles. Users can pick up a vehicle from any station and drop it off to any other station. However, due to asymmetric demand patterns eventually all vehicles end up at the stations with no demand, decreasing throughput performance. This paper presents an ongoing research for a new computational framework in System Dynamics that describes distribution of resource allocation in a vehicle sharing system under non homogenous demand patterns by simulating the resource flow between areas of high density to areas of low density as demand pattern changes. The framework will be used as study tool to understand behavior and explore organizational solutions.

Proceedings of the Ninth International Conference on Tangible, Embedded, and Embodied Interaction, 2015

Today, it is not uncommon to find ourselves remote from those we care about. Despite the impact o... more Today, it is not uncommon to find ourselves remote from those we care about. Despite the impact of mobile and social technologies on connectedness, recent studies suggest that it could be these very technologies that exacerbate a sense of loneliness. In attempt to help people feel more connected, we designed and created BodyPods, a remotely paired set of communicating chairs that facilitate a sense of presence by leveraging implicit actions such as sitting to communicate that someone you care about is home. Each BodyPod consists of a flexible surface with six pressure-sensitive and light-emitting pads that adjusts its shape to the body anatomy. As a person's body moves, limbs exert different pressure on each pad creating a live digital "bodyprint" that is mapped on the pads of other BodyPods through color and light. Findings from a 10 person user study suggest bodyprints may be distinctive, particularly among small groups of people with different body types.

Computer-supported scenario analysis is a fundamental practice in urban planning in which a decis... more Computer-supported scenario analysis is a fundamental practice in urban planning in which a decision-maker formulates a question and a computer model simulates the hypothetical scenario for subsequent assessment. This paper concentrates on scenario analysis for sizing and rebalancing tradeoffs for mobility on demand (MoD) systems. Developing such models is challenging because trip patterns are by definition random while rebalancing patterns require first solving routing, a computationally intractable problem even for medium-sized systems. Using Boston's bike sharing system as a case, we present a novel approach based on reconstructing accumulation dynamics, showing that, independently of system or trip pattern characteristics, vehicle mass in MoD systems moves periodically between two types of locations and accumulates between two other types of locations. Following this, we present a method to build data-driven system dynamics macromodels that allow decision makers to interacti...

International Journal of Architectural Computing, 2021

107th ACSA Annual Meeting Proceedings, Black Box, 2019

Architecture and Culture, 2019

Proceedings of the 24th Conference on Computer Aided Architectural Design Research in Asia (CAADRIA) [Volume 2]

2013 9th International Conference on Intelligent Environments, 2013

This paper describes the development of a pedagogy that aims to engage architecture students in p... more This paper describes the development of a pedagogy that aims to engage architecture students in principles of mechanical computation and to develop critical thinking on how information and computation can be manifested and performed tectonically. I pose the question: Can we create architectures that compute?

Communications in Computer and Information Science

BLACK BOX: Articulating Architecture’s Core in the Post-Digital Era, 2019

This essay discusses the development of a pedagogical approach that uses principles of mechanical... more This essay discusses the development of a pedagogical approach that uses principles of mechanical computation as a means to critically inquiry how information and computation can be manifested and performed tectonically through architecture. Drawing examples from the development of two courses, I pose the question: is computing designable? how might we design architecture that computes? Selected student projects are presented and discussed.

Architectural Computing - Pedagogical Experiments at the Intersection of Architectural Design and Mechanical Computation, 2019

Architecture and Culture, Nov 4, 2019

In their book Reinventing the Automobile, William Mitchell, Chris Borroni-Bird, and Larry Burns u... more In their book Reinventing the Automobile, William Mitchell, Chris Borroni-Bird, and Larry Burns unravel a fascinating vision for technologically driven, shared, on-demand, mobility systems. Today, shared mobility-on-demand systems are one of the most rapidly growing sectors of urban transport, yet, the average shared vehicle is often as inefficient as a privately owned one. In this essay, I argue that the question of sharing versus owning is one that depends less on planning, technology, and operations, as the authors of the book suggest, and more on contextual factors such as urban form, land use distribution, and user behaviour. I organize my argument in three parts. First, I provide a definition of cost of shared mobility that serves as a basis for comparing shared with privately owned mobility. Next, I critique three common arguments in support of mobility-on-demand systems. Finally, I frame the question of sharing versus owning in a generalized yet addressable manner and I suggest new methodological directions to address it.

Choreographies of Information: Communication through Architectural Form in the Early Napoleonic Internet of Optical Telegraphy, 2015

Today, it is not uncommon to find ourselves remote from those we care about. Despite the impact o... more Today, it is not uncommon to find ourselves remote from those we care about. Despite the impact of mobile and social technologies on connectedness, recent studies suggest that it could be these very technologies that exacerbate a sense of loneliness. In attempt to help people feel more connected, we designed and created BodyPods, a remotely paired set of communicating chairs that facilitate a sense of presence by leveraging implicit actions such as sitting to communicate that someone you care about is home. Each BodyPod consists of a flexible surface with six pressure-sensitive and light-emitting pads that adjusts its shape to the body anatomy. As a person’s body moves, limbs exert different pressure on each pad creating a live digital “bodyprint” that is mapped on the pads of other BodyPods through color and light. Findings from a 10 person user study suggest bodyprints may be distinctive, particularly among small groups of people with different body types.

This paper discusses the design, process, and results of an experimental workshop with mid-school... more This paper discusses the design, process, and results of an experimental workshop with mid-school students that introduced the theory, underlying technologies, and operational challenges of smart urban systems. Students brainstormed ideas of how to use electronics, interaction design and game theory to make bike- sharing systems that incentivize users to rebalance bikes through rewards/penalties. Furthermore they tested their ideas by collaboratively designing, prototyping, and playing an interactive board game implementing both theory and technology. Through their game students explored questions such as: how can we create coordinated behavior from self-interested players? How and when can the game reach a sustainable equilibrium? In what other systems can we apply similar concepts?

Mobility on Demand (MoD) systems allow users to pick-up and drop-off vehicles (bikes, automobiles... more Mobility on Demand (MoD) systems allow users to pick-up and drop-off vehicles (bikes, automobiles) ubiquitously in networks of parking stations. Asymmetric trip patterns cause imbalanced fleet allocation decreasing level of service. Current redistribution policies are complex to plan and typically cost more than the usage revenues of the system. This paper discusses a new operation model based on a double auction market where cost-minimizing users are both buyers and sellers of trip rights while profit-maximizing stations are competing auctioneers that trade them. Thus, trips are priced relatively to the inventory needs of origin and destination stations, causing some trips to be more expensive while other trips to pay back.

Proceedings of the 26th International Conference on Education and Research in Computer Aided Architectural Design in Europe (eCAADe)

Adjunct Proceedings of the 2019 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2019 ACM International Symposium on Wearable Computers, 2019

Annual Simulation Symposium, Apr 3, 2011

Proceedings of the Ninth International Conference on Tangible, Embedded, and Embodied Interaction, 2015

International Journal of Architectural Computing, 2021

107th ACSA Annual Meeting Proceedings, Black Box, 2019

Architecture and Culture, 2019

Proceedings of the 24th Conference on Computer Aided Architectural Design Research in Asia (CAADRIA) [Volume 2]

2013 9th International Conference on Intelligent Environments, 2013

Communications in Computer and Information Science

BLACK BOX: Articulating Architecture’s Core in the Post-Digital Era, 2019

Architectural Computing - Pedagogical Experiments at the Intersection of Architectural Design and Mechanical Computation, 2019

Architecture and Culture, Nov 4, 2019

Choreographies of Information: Communication through Architectural Form in the Early Napoleonic Internet of Optical Telegraphy, 2015

Today, it is not uncommon to find ourselves remote from those we care about. Despite the impact o... more Today, it is not uncommon to find ourselves remote from those we care about. Despite the impact of mobile and social technologies on connectedness, recent studies suggest that it could be these very technologies that exacerbate a sense of loneliness. In attempt to help people feel more connected, we designed and created BodyPods, a remotely paired set of communicating chairs that facilitate a sense of presence by leveraging implicit actions such as sitting to communicate that someone you care about is home. Each BodyPod consists of a flexible surface with six pressure-sensitive and light-emitting pads that adjusts its shape to the body anatomy. As a person’s body moves, limbs exert different pressure on each pad creating a live digital “bodyprint” that is mapped on the pads of other BodyPods through color and light. Findings from a 10 person user study suggest bodyprints may be distinctive, particularly among small groups of people with different body types.

Unconventional Computing: Design Methods for Adaptive Architecture, ed. Simone Ferracina and Rachel Armstrong (Riverside Architectural Press, 2013), 2013

Infrastructure Sustainability and Design, ed. Spiro Pollalis et al. (Routledge, 2012), 266-274, 2012

It has been a common misbelief that intelligence and coordinated behavior is the result of single... more It has been a common misbelief that intelligence and coordinated behavior is the result of single minds’ activity. In his seminal work “The Society of Mind” Marvin Minsky described a new model to explain intelligence consisting of a distributed social network of connected agents, the behavior of whom is driven by their personal goals, beliefs, and constraints as a response to external stimuli. Minsky argued that intelligence is thus not a single mind phenomenon, but instead the product of properly wired collective behavior. Today, current research on distributed sensor networks uses market mechanisms and basic microeconomic behavior as the means to create emergent patterns of collective intelligence for managing resource allocation among the sensor nodes. How can these ideas be used to create smarter urban environments?

Interdisciplinary Design: New Lessons from Architecture and Engineering, ed. Hanif Kara et al. (ACTAR Press, 2012), 106-114, 2012

Is it the form that drives design and production process, or instead the processes themselves tha... more Is it the form that drives design and production process, or instead the processes themselves that determine forms? While often design expressionism pushes engineering ingenuity to invent new solutions, it is typically technology innovation that offers the tools to designers to explore new formalistic domains. Through the course of history design practice has been integrating technology, people and materials to invent new methods to increase form customization while decreasing production costs. We are witnessing a transformation of the building industry of what was previously known as empirical craftsmanship to today’s highly controlled digital fabrication. Nevertheless, today’s digital technology’s achievements seem to open more questions in design practice and research than the answers they provide.

People sharing the same space but having different time schedules often perceive each other’s pre... more People sharing the same space but having different time schedules often perceive each other’s presence through the implicit traces their interactions with physical objects leave behind. If John, returning home after Sarah has left, feels the sofa warm, he may infer that Sarah was sitting there recently. What if we could allow remotely located people have the same emotional experience as John and Sarah have? BodyPods is a pair of multi sensory seats to emotionally connect remotely located people by sensing, exchanging, and visually expressing the “bodyprints” of their users as live gestural expressions through the Internet. Analogous to a footprint, a bodyprint manifests a person’s sitting posture as a distribution of the pressure that their body and limbs exert against the cushions of the seat. When a person sits on one BodyPod, his/her bodyprint is reflected on the pads of the other BodyPod through color and light. Findings from a 10 person user study suggest bodyprint signatures may be distinctive, particularly among small groups of people with different body types, allowing BodyPods to act as novel user recognition interfaces.

Object-based social connectedness is an established area in HCI and TEI with most prior works focusing on the explicit, synchronous, and deliberate interactions. In contrast, we are interested in the ability of objects to connect people asynchronously by capturing and sharing implicit traces of human activity that fade over time. We are also interested in the concept of a bodyprint as a digital signature of the person’s identity and activity. Motivated by the Affordance Theory, we chose pressure because we believe it is a modality that the act of sitting affords better. Prior works on posture-sensing chairs focused on retrofitting existing designs with multiple sensors resulting in significant computational complexity with signal analysis. Our approach instead was to rethink the design and function of a seat in order to minimize the number of sensors and simplify their input analysis. BodyPods can detect eight postures using only six pressure sensors and a simple signal processing through a novel flexible shape that adjusts to body anatomy ensuring consistent contact with the sensors during posture transitions.

Contributions: [1] We present a novel kinematically deformable seat design that uses only six pressure sensitive units to capture body postures. [2] We introduce the concept of bodyprint as a means to visually communicate, synchronously or asynchronously, seated postures and potentially user identities. [3] We present findings from design, material and fabrication explorations that can be useful to designers and researchers in the field of TEI interested in augmented furniture.

The Cloudcommuting workshop introduced 6 middle-school students to the theory, technology, and op... more The Cloudcommuting workshop introduced 6 middle-school students to the theory, technology, and operational complexity of intelligent Mobility on Demand (MoD) systems. MoD systems use networks of parking stations and shared fleets of vehicles (bikes, scooters, auto- mobiles) allowing users to make point-to-point trips on demand. We asked students to imagine an intelligent, self-organizing MoD system that senses inventory imbalances, and rewards (penalizes) trips from full (empty) to empty (full) stations. Furthermore, to collaboratively de- sign, make, and play an interactive board game to demonstrate and test their ideas in practice.
Students were organized into 4 interdependent teams, based on the feedback loop of the game: the game design team created the deci- sion-making rules, economics, and layout of the game; the electron- ics team prototyped the stations that sense inventory levels and send messages to a server; the visualization team programmed the server to receive these messages and project price information back to the stations. Finally, the simulation team developed a multi-agent model to study the complex behavior of the system. Through their game students explored questions such as: how can we create coordinated behavior from self-interested players? How and when can the game reach a sustainable equilibrium? In what other systems can we apply similar concepts?
In CloudCommuting, students did not design a representation of an ecosystem; instead they created the ecosystem itself and engineered its interaction with the human world: students became designers, engineers, visualizers, builders, economists, simulators, and most of all, negotiators trying to determine what works with the experts of the other teams. Most importantly, through their collaboration students learned that no team could work without the feedback of the others. For example, visualization depended on the technology of the electronics while their decisions depended in turn on the concept of the game design.

The Market Economy of Trips (MET) investigates the potential of using market incentive mechanisms... more The Market Economy of Trips (MET) investigates the potential of using market incentive mechanisms and a visual information system to create sustainable, self-organizing, one-way vehicle sharing systems. That is systems requiring minimum central intervention.
One-way vehicle sharing systems are distributed urban mobility networks of vehicles and parking stations that allow users to conveniently pick up a vehicle from any station and drop it off to any other station. Popular examples are bike sharing programs however this trend is rapidly entering automobile markets.
Despite their great convenience vehicle sharing systems have drawbacks too. Due to asymmetric demand patterns, eventually all vehicles are ending at the stations with no demand. This inventory imbalance, not only decreases through- put, but it furthermore increases trip time as drivers search for parking spaces. Existing policies redistribute manually vehicles, which is a complex, inefficient, and highly unsustainable solution. As a consequence, many vehicle sharing systems end up wasting more resources for sustaining their performance than the value of the service they provide.
We explore a new strategy to create autonomous self-organizing vehicle sharing systems that uses price incentives to smooth demand imbalances, and an interactive graphical user interface to intuitively communicate location-based price information to the users. Similarly to a market economy, prices adjust dynamically to parking needs incentivizing users to drive vehicles to stations that mostly need them while discouraging arrivals to stations that don’t need them.
In this paper we explain decision-making in dynamically priced mobility systems, explore the conditions under which a stable equilibrium state may exist, and if so, whether local price calculation and visual perception of the price landscape is sufficient to bring it. Is there a pricing policy that can make the system self-sustaining such that the funds from its overpaying users are enough to reward its underpaying users? How efficient can a dynamically priced vehicle sharing system be?
To address these questions we develop and conduct a game experiment to empirically evaluate users’ visual perception of payoffs, and a computational framework using System Dynamics and Urban Economics, to explore the lim- its of efficiency of MET under different demand patterns, pricing policies and population’s income distribution.