@conference {
	title = {Modeling Air Traffic Throughput and Delay with Network Cell Transmission Model},
	author = {Nguyen, Alex T., Baras, John S.},
	year = {2010},
	month = {05/2010},
	abstract = {In practice, the model is envisioned to initially run offline to determine a preliminary solution to the initial state of the system. Solutions for subsequent changes in actual state can be determined by running the model online for the incremental state change. Stochastic events such as convective weather clearing times or capacities can be included in the model to better see the benefits and impacts of pre-positioning traffic to take advantage of possible future clearing.},
	address = {Herndon, VA},
	booktitle = { Integrated Communications Navigation and Surveillance Conference (ICNS 2010)},
	pages = {pp. 1-14}
}
@conference {
	title = {Network Cell Routing Model For Control of Throughput and Delay of Air Traffic},
	author = {Nguyen, Alex T., Baras, John S.},
	year = {2009},
	month = {10/2009},
	abstract = {Attempts to manage air traffic by either decreasing delay or increasing flow can have the reverse effect on the other. In the National Airspace System (NAS), flights typically depart at their chosen times, and flow management techniques are implemented in the air in an effort to maximize flow, which could lead to delay for individual aircraft. Other areas of the world allow flights to depart only at predetermined slot times knowing that there is a clear unobstructed path, leading to minimal delays but possibly under utilizing airspace. We propose a new approach in leveraging the highway cell transmission model (CTM) to the airspace in the form of a multi-objective optimization that trades between maximizing throughput and minimizing delay. The model is posed as a multi commodity traffic flow integer program where the constraints are relaxed slightly from the CTM to examine strategies for achieving optimal throughput and delay. In practice, the model is envisioned to initially run offline to determine a preliminary solution to the initial state of the system. Solutions for subsequent changes in actual state can be determined by running the model online for the incremental state change. Stochastic events such as convective weather clearing times or capacities can be included in the model to better see the benefits and impacts of pre-positioning traffic to take advantage of possible future clearing.},
	address = {Orlando, FL},
	booktitle = {28th Digital Avionics Systems Conference (DASC - 2009)},
	pages = {pp. 2.B.2-1 - 2.B.2-6}
}
@conference {
	title = {Network Cell Air Traffic Routing Model For Control of Throughput and Delay},
	author = {Nguyen, Alex T., Baras, John S.},
	year = {2009},
	month = {10/2009},
	abstract = {Attempts to manage air traffic by either decreasing delay or increasing flow can have the reverse effect on the other. In the National Airspace System (NAS), flights typically depart at their chosen times, and flow management techniques are implemented in the air in an effort to maximize flow, which could lead to delay for individual aircraft. Other areas of the world allow flights to depart only at predetermined slot times knowing that there is a clear unobstructed path, leading to minimal delays but possibly underutilizing airspace. We propose a new approach in leveraging the highway cell transmission model (CTM) to the airspace in the form of a multi-objective optimization that trades between maximizing throughput and minimizing delay. The model is posed as a multicommodity traffic flow integer program where the constraints are relaxed slightly from the CTM to examine strategies for achieving optimal throughput and delay. In practice, the model is envisioned to initially run offline to determine a preliminary solution to the initial state of the system. Solutions for subsequent changes in actual state can be determined by running the model online for the incremental state change. Stochastic events such as convective weather clearing times or capacities can be included in the model to better see the benefits and impacts of pre-positioning traffic to take advantage of possible future clearing.},
	address = {San Diego, CA},
	booktitle = {INFORMS 2009},
	pages = {2.B.2-1 - 2.B.2-6}
}
@conference {
	title = {Alternative Network Architectures for Supporting Communications From the International Space Station},
	author = {Nguyen, Alex T., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2002},
	month = {05/2002},
	abstract = {In order to support the communications needs of the International Space Station (ISS), alternative communications architectures to provide broadband support need to be considered. We address three communications options and evaluate an architecture for the direct to ground option, which could serve as an intermediary solution to satisfy near term communications needs of commercial experiments and payloads on the ISS and overcome certain limitations of the current ISS communications infrastructure. We focus on a particular user{\textquoteright}s requirements, and examine the system{\textquoteright}s communications links, and coverage availability. These parameters, along with high-level cost estimates, are compared to using commercial relay satellites, and an enhanced TDRSS. The direct to ground option is viable for store-and-forward applications and cost comparable to commercial constellations, but TDRSS is the choice for realtime or continuous data applications.},
	address = {Quebec, Canada},
	booktitle = {20th AIAA International Communication Satellite systems Conference and Exhibit},
	pages = {pp. 1-10},
	organization = {Montreal}
}
@techreport {
	title = {A direct-to-ground architecture for supporting Commercial Communications from the International Space Station},
	author = {Nguyen, Alex T., Zhou, Xiangrong., Hadjitheodosiou, Michael.},
	year = {2002},
	month = {01/2002},
	abstract = {We outline the first steps of an effort to start defining a communications architecture for supporting broadband data communications from the International Space Station. We address three communications options and focus on a direct-to-ground architecture, which could serve as an intermediary solution to satisfy near-term communications needs of commercial experiments and payloads on the ISS and overcome certain limitations of the current ISS communications infrastructure. A high-level analysis of the architecture for the direct to ground option is performed, focusing on a particular user{\textquoteright}s requirements, communications links, and coverage availability. We also discuss system, mobility support and protocol issues that need to be addressed for this solution to be a feasible alternative.},
	address = {New York, NY}
}
@conference {
	title = {A direct-to-ground architecture for supporting commercial communications from the International Space Station},
	author = {Nguyen, Alex T., Zhou, Xiangrong., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2002},
	month = {04/2002},
	abstract = {We outline the first steps of an effort to start defining a communications architecture for supporting broadband data communications from the International Space Station. We focus on a direct-to-ground architecture, which could serve as an intermediate solution to satisfy the near term communications needs of commercial experiments and payloads on the ISS and overcome certain limitations of the current ISS communications infrastructure. We address three communications options and evaluate an architecture for the direct-to-ground option, focusing on a particular user{\textquoteright}s requirements, communications links, and coverage availability. We also discuss system, mobility support and protocol issues that need to be addressed for this solution to be a feasible alternative.},
	address = {New York, NY},
	booktitle = {IEEE International Conference on Communications},
	pages = {pp. 2989-2993}
}
@article {
	title = {Broadband Communication Support for Earth Observation from the International Space Station},
	author = {Nguyen, Alex T., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2004},
	month = {10/2004},
	abstract = {In order to support the communications needs of Earth-observing instruments on the International Space Station (ISS), alternative communications architectures to provide broadband support need to be considered. In this paper, we evaluate the direct-to-ground option in terms of coverage. We show that a direct-to-ground option is a feasible solution to enhance the limited communication capabilities provided by the current ISS infrastructure. In order to ensure efficient end-to-end communication support and deal with the complications of the space environment, COTS equipment with recently demonstrated protocol modifications needs to be adopted. We also demonstrate that selecting the most appropriate location for placement of the ground stations is an important design issue that can ensure optimal coverage and maximize throughput. As both the need for broadband services from the ISS and from other upcoming space missions increases, this option will play a role in enhancing the currently limited space-relay architecture until a next generation relay system is deployed.},
	pages = {pp. 375-388},
	volume = {Vol. 46},
	number = {Issue 3},
	journal = {Computer Networks Journal}
}
@techreport {
	title = {Alternative Network Architectures for Supporting Communications from the International Space Station},
	author = {Nguyen, Alex T., Hadjitheodosiou, Michael.},
	year = {2002},
	month = {01/2002},
	abstract = {In order to support the communications needs of the International Space Station (ISS), alternative communications architectures to provide broadband support need to be considered. We address three communications options and evaluate an architecture for the direct to ground option, which could serve as an intermediary solution to satisfy near term communications needs of commercial experiments and payloads on the ISS and overcome certain limitations of the current ISS communications infrastructure. We focus on a particular user\&rsquo;s requirements, and examine the system\&rsquo;s communications links, and coverage availability. These parameters, along with high-level cost estimates, are compared to using commercial relay satellites, and an enhanced TDRSS. The direct to ground option is viable for store-and-forward applications and cost comparable to commercial constellations, but TDRSS is the choice for real-time or continuous data applications.},
	number = {Number: CSHCN TR 2002-9}
}
