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Papers by Ranga Jayaraman

Interfaces, 1999

We built and deployed a decision-support system for scheduling paper manufacturing and distributi... more We built and deployed a decision-support system for scheduling paper manufacturing and distribution, an extremely complex task with multiple stages of production and strong interaction between stages. In contrast to earlier approaches, our system considers multiple scheduling objectives and multiple stages of production and distribution simultaneously using multiple evaluation criteria. Our system functions as an intelligent assistant to the schedulers and generates multiple good scheduling alternatives using a portfolio of algorithms and direct human-expert input. The successful deployment of our system at several paper mills in North America has resulted in significant savings, greater customer satisfaction, and improved business processes.

Research Report, IBM …, 1992

We consider a multi-period, two level product-component con guration where many of the components... more We consider a multi-period, two level product-component con guration where many of the components are common to several products. The demands for ... Key Words: Commonality, Inventory, Service Constraint, Approx-imations. ... IBM TJ Watson Research Center, Yorktown Heights, NY ...

Robotics and Automation, IEEE …, 1989

... This limits 1042-296X/89/0600-0324$01 .OO O 1989 IEEE Page 2. LEVAS AND JAYARAMAN: MODELING A... more ... This limits 1042-296X/89/0600-0324$01 .OO O 1989 IEEE Page 2. LEVAS AND JAYARAMAN: MODELING AND SIMULATION OF WORKCELL APPLICATIONS 325 ... Page 6. LEVAS ANDJAYARAMAN: MODELING AND SIMULATION OF WORKCELL APPLICATIONS 329 ...

Interfaces, 1999

In this paper, we discuss a new decision-support system for scheduling paper manufacturing and di... more In this paper, we discuss a new decision-support system for scheduling paper manufacturing and distribution. Scheduling production and distribution of paper is an extremely complex task requiring the consideration of numerous constraints and objectives. Problem complexity is compounded by process interactions wherein the scheduling of one stage of the production process may negatively impact downstream processes. In contrast to earlier approaches, our system considers multiple scheduling objectives and multiple stages of paper manufacturing and distribution simultaneously in a global multi-criteria optimization framework. It generates multiple scheduling alternatives by using several algorithms based on approaches such as linear/integer programming, network flow methods and heuristics. These alternatives reveal tradeoffs with respect to competing objectives, such as maximizing profitability, on-time delivery, product quality, and minimizing manufacturing disruptions. Each scheduling alternative is a complete enterprise schedule that includes sub-schedules for each stage of the manufacturing process and loading. The scheduler can work cooperatively with the system to explore alternatives and to improve solution quality. As the final decision maker, the scheduler can choose the best alternative for the enterprise. By functioning as an intelligent assistant, our system relieves the schedulers of mundane computational tasks and allows them to focus on the objectives of the enterprise and decision making. For generating multiple solutions and facilitating cooperation with the scheduler, our system is implemented using the agent based Asynchronous Team (A-Team) architecture in which multiple solution methods cooperate by evolving a shared population of solutions. The successful deployment of our system at several paper mills in North America has resulted in significant savings and improved customer satisfaction. These positive results arose from improved schedule quality and improvements in the business process that our decision-support approach has fostered.

Turbulent boundary layers with a time-dependent free-stream velocity occur in many fluid dynamic ... more Turbulent boundary layers with a time-dependent free-stream velocity occur in many fluid dynamic devices. The main objective of the present work are as follows: (1) to understand the characteristics of a turbulent boundary layer that develops under steady, zero-pressure gradient ...

This paper reports experiments on an unsteady turbulent boundary layer. The upstream portion of t... more This paper reports experiments on an unsteady turbulent boundary layer. The upstream portion of the flow is steady (in the mean). In the downstream region, the boundary layer saes a linearly decreasing free-stream velocity. This velocity gradient oscillates in time, at frequencies ranging from zero to approximately the bursting frequency. Considerable detail is reported for a low-amplitude case, and preliminary results are given for a higher amplitude sufficient to produce some reverse flow. For the small amplitude, the mean velocity and mean turbulence intensity profiles are unaffected by the oscillations. The amplitude of the periodic velocity component, although as such as 70Z greater than that in the free stream for very low frequencies, becomes equal to that in the free stream at higher frequencies. At high frequencies, both the boundary layer thickness and tLe Raynolds stress distribution across the boundary layer become frozen. The behavior at larger amplitude is quite similar. Most importantly, at sufficiently high frequencies the boundary layer thickness remains frozen at its mean value over the oscillation cycle, even though flow reverses near the wall during a part of the cycle.

CAD Based Programming for Sensory Robots, 1988

... X. Authors, R. Jayaraman, Thomas J. Watson Research Center, Yorktown Heights, NY. A. Levas, T... more ... X. Authors, R. Jayaraman, Thomas J. Watson Research Center, Yorktown Heights, NY. A. Levas, Thomas J. Watson Research Center, Yorktown Heights, NY. Publisher, Springer-Verlag New York, Inc. New York, NY, USA. Bibliometrics, ...

Journal of Fluid Mechanics, 1990

... 138 G . J . Brereton, W. C . Reynolds and R. Jayaraman ... scaling deduced from the channel-f... more ... 138 G . J . Brereton, W. C . Reynolds and R. Jayaraman ... scaling deduced from the channel-flow data of Luchik & Tiederman (1987) (u,2/[vfB] x 90) implied this frequency would take a value of 3.6 Hz, whereas the outer scaling of Rao, Narasimha & Badri Narayanan (1971) (U/[S*f ...

IEEE Spectrum, 2000

Oftentimes in complex design, development, and production projects, the communication and informa... more Oftentimes in complex design, development, and production projects, the communication and information exchange requirements far exceed the capabilities of ordinary computer-aided design, computerintegrated manufacturing, and concurrent engineering systems and their product-data models. Such activities as project management, team meetings, sales, service, advertising, and accounting similarly require information exchange and support systems. This, then, is where the burgeoning study of collaborative environments comes in.

AIAA Journal, 1982

ABSTRACT

Interfaces, 1999

We built and deployed a decision-support system for scheduling paper manufacturing and distributi... more We built and deployed a decision-support system for scheduling paper manufacturing and distribution, an extremely complex task with multiple stages of production and strong interaction between stages. In contrast to earlier approaches, our system considers multiple scheduling objectives and multiple stages of production and distribution simultaneously using multiple evaluation criteria. Our system functions as an intelligent assistant to the schedulers and generates multiple good scheduling alternatives using a portfolio of algorithms and direct human-expert input. The successful deployment of our system at several paper mills in North America has resulted in significant savings, greater customer satisfaction, and improved business processes.

Research Report, IBM …, 1992

We consider a multi-period, two level product-component con guration where many of the components... more We consider a multi-period, two level product-component con guration where many of the components are common to several products. The demands for ... Key Words: Commonality, Inventory, Service Constraint, Approx-imations. ... IBM TJ Watson Research Center, Yorktown Heights, NY ...

Robotics and Automation, IEEE …, 1989

... This limits 1042-296X/89/0600-0324$01 .OO O 1989 IEEE Page 2. LEVAS AND JAYARAMAN: MODELING A... more ... This limits 1042-296X/89/0600-0324$01 .OO O 1989 IEEE Page 2. LEVAS AND JAYARAMAN: MODELING AND SIMULATION OF WORKCELL APPLICATIONS 325 ... Page 6. LEVAS ANDJAYARAMAN: MODELING AND SIMULATION OF WORKCELL APPLICATIONS 329 ...

Interfaces, 1999

In this paper, we discuss a new decision-support system for scheduling paper manufacturing and di... more In this paper, we discuss a new decision-support system for scheduling paper manufacturing and distribution. Scheduling production and distribution of paper is an extremely complex task requiring the consideration of numerous constraints and objectives. Problem complexity is compounded by process interactions wherein the scheduling of one stage of the production process may negatively impact downstream processes. In contrast to earlier approaches, our system considers multiple scheduling objectives and multiple stages of paper manufacturing and distribution simultaneously in a global multi-criteria optimization framework. It generates multiple scheduling alternatives by using several algorithms based on approaches such as linear/integer programming, network flow methods and heuristics. These alternatives reveal tradeoffs with respect to competing objectives, such as maximizing profitability, on-time delivery, product quality, and minimizing manufacturing disruptions. Each scheduling alternative is a complete enterprise schedule that includes sub-schedules for each stage of the manufacturing process and loading. The scheduler can work cooperatively with the system to explore alternatives and to improve solution quality. As the final decision maker, the scheduler can choose the best alternative for the enterprise. By functioning as an intelligent assistant, our system relieves the schedulers of mundane computational tasks and allows them to focus on the objectives of the enterprise and decision making. For generating multiple solutions and facilitating cooperation with the scheduler, our system is implemented using the agent based Asynchronous Team (A-Team) architecture in which multiple solution methods cooperate by evolving a shared population of solutions. The successful deployment of our system at several paper mills in North America has resulted in significant savings and improved customer satisfaction. These positive results arose from improved schedule quality and improvements in the business process that our decision-support approach has fostered.

Turbulent boundary layers with a time-dependent free-stream velocity occur in many fluid dynamic ... more Turbulent boundary layers with a time-dependent free-stream velocity occur in many fluid dynamic devices. The main objective of the present work are as follows: (1) to understand the characteristics of a turbulent boundary layer that develops under steady, zero-pressure gradient ...

This paper reports experiments on an unsteady turbulent boundary layer. The upstream portion of t... more This paper reports experiments on an unsteady turbulent boundary layer. The upstream portion of the flow is steady (in the mean). In the downstream region, the boundary layer saes a linearly decreasing free-stream velocity. This velocity gradient oscillates in time, at frequencies ranging from zero to approximately the bursting frequency. Considerable detail is reported for a low-amplitude case, and preliminary results are given for a higher amplitude sufficient to produce some reverse flow. For the small amplitude, the mean velocity and mean turbulence intensity profiles are unaffected by the oscillations. The amplitude of the periodic velocity component, although as such as 70Z greater than that in the free stream for very low frequencies, becomes equal to that in the free stream at higher frequencies. At high frequencies, both the boundary layer thickness and tLe Raynolds stress distribution across the boundary layer become frozen. The behavior at larger amplitude is quite similar. Most importantly, at sufficiently high frequencies the boundary layer thickness remains frozen at its mean value over the oscillation cycle, even though flow reverses near the wall during a part of the cycle.

CAD Based Programming for Sensory Robots, 1988

... X. Authors, R. Jayaraman, Thomas J. Watson Research Center, Yorktown Heights, NY. A. Levas, T... more ... X. Authors, R. Jayaraman, Thomas J. Watson Research Center, Yorktown Heights, NY. A. Levas, Thomas J. Watson Research Center, Yorktown Heights, NY. Publisher, Springer-Verlag New York, Inc. New York, NY, USA. Bibliometrics, ...

Journal of Fluid Mechanics, 1990

... 138 G . J . Brereton, W. C . Reynolds and R. Jayaraman ... scaling deduced from the channel-f... more ... 138 G . J . Brereton, W. C . Reynolds and R. Jayaraman ... scaling deduced from the channel-flow data of Luchik & Tiederman (1987) (u,2/[vfB] x 90) implied this frequency would take a value of 3.6 Hz, whereas the outer scaling of Rao, Narasimha & Badri Narayanan (1971) (U/[S*f ...

IEEE Spectrum, 2000

Oftentimes in complex design, development, and production projects, the communication and informa... more Oftentimes in complex design, development, and production projects, the communication and information exchange requirements far exceed the capabilities of ordinary computer-aided design, computerintegrated manufacturing, and concurrent engineering systems and their product-data models. Such activities as project management, team meetings, sales, service, advertising, and accounting similarly require information exchange and support systems. This, then, is where the burgeoning study of collaborative environments comes in.

AIAA Journal, 1982

ABSTRACT