DSpace at MIT
(35.360 recursos)
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Mostrando recursos 1 - 10 de 10
1.
Precision Robot Calibration Using Kinematically Placed Inclinometers - Robertson, Alec P.; Slocum, Alexander; Willoughby, Patrick J.
In the field of industrial robotics, many different calibration methods exist to reduce error in the
robot system. Locating the manipulator home position is a common calibration technique, which
can be divided into three main categories ? relative, optimal and leveling based methods. The
home position of an industrial manipulator is a position where all joint angles have a pre-defined
value (e.g. zero or 90 degrees), which can be transformed into Cartesian space via the robot
kinematics. Large industrial manipulators, with a working range in the order of several meters,
require an accurately defined home position that can be restored with repeatability in the order of
0.2mm...
2.
Analyzing Multiple Product Development Projects Based On Information and Resource Constraints - Yassine, Ali; Browning, Tyson
Product development (PD) and engineering design processes are often characterized by the
information flowing among activities. In PD, this flow forms a complex activity web?a process
that can be viewed as a complex system. Most literature on the subject of information flow in
PD focuses on a single project, where precedence information constraints (based solely on
necessary information and possible assumptions) determine the execution sequence for the
activities and the resultant project lead-time. In this paper, we consider multiple PD projects that
share a common set of design resources. Especially in this setting, precedence information
availability is insufficient to assure that activities will execute on time. We...
3.
Performance of Coupled Product Development Activities with a Deadline - Joglekar, Nitindra R.; Whitney, Daniel E.; Yassine, Ali A.; Eppinger, Steven D.
This paper explores the performance of coupled development tasks subject to a deadline constraint
by proposing a performance generation model (PGM). The goal of the PGM is to develop insights
about optimal strategies (i.e. sequential, concurrent, or overlapped) to manage coupled design tasks
that share fixed amount of engineering resources subject to performance and deadline constraints.
Model analysis characterizes the solution space for the coupled development problem. The solution
space is used to explore the generation of product performance and the associated dynamic forces
affecting concurrent development practices. We use these forces to explain conditions under which
concurrency is a desirable strategy.
4.
Do-It-Right-First-Time (Draft) Approach To Design Structure Matrix (DSM) Restructuring - Whitney, Daniel E.; Yassine, Ali A.; Lavine, Jerry; Zambito, Tony
This paper argues, using two real-world applications from
the automotive industry, that the biggest benefit of a Design
Structure Matrix (DSM) model may come not from resequencing
and partitioning, but rather from ?rewiring? the
process/blocks. ?Rewiring? means redefining relationships
among elements and/or inserting new elements into the
matrix. This requires intimate understanding of the process
and cannot be done with application of context-free
partitioning algorithms.
The Do-it-Right-First-Time (DRFT) approach to DSM
restructuring is another way to look at a DSM by inspecting
the sources of iteration within a block and reversing it through
inserting a DRFT activity at the beginning of the block. In this
way, the traditional Design-Build-Test ?Cycle? is reversed into
a...
5.
Assessment of Rework Probabilities for Simulating Product Development Processes Using the Design Structure Matrix (DSM) - Yassine, Ali A.; Whitney, Daniel E.; Zambito, Tony
This paper uses the Design Structure Matrix (DSM) to
model and simulate the performance of development processes.
Though the simulation is a powerful tool for analyzing process
performance, its ability is limited by the quality of input
information used in the analysis. DSM simulation requires
process data that is hard to assess or estimate directly from
development participants. In this paper, we propose a
methodology that allows a more practical estimation of an
important simulation parameter: rework probabilities.
Furthermore, we show how does this assessment method
(combined with simulation) allow managers to evaluate process
improvement plans based on two resulting process measures:
reliability and robustness. The method is illustrated with a real
application...
6.
A Statistical Model of Vehicle Emissions and Fuel Consumption - Cappiello, Alessandra; Chabini, Ismail; Lue, Alessandro; Zeid, Maya Abou; Nam, Edward K.
Many vehicle emission models are overly simple, such
as the speed dependent models used widely, and other models are
sufficiently complicated as to require excessive inputs and
calculations, which can slow down computational time. We
develop and implement an instantaneous statistical model of
emissions (CO2, CO, HC, and NOx) and fuel consumption for
light-duty vehicles, which is simplified from the physical loadbased
approaches that are gaining in popularity. The model is
calibrated for a set of vehicles driven on standard as well as
aggressive driving cycles. The model is validated on another
driving cycle in order to test its estimation capabilities. The
preliminary results indicate that the model gives reasonable
results compared...
7.
A Statistical Model of Vehicle Emissions and Fuel Consumption - Cappiello, Alessandra; Chabini, Ismail; Nam, Edward K.; Lue, Alessandro; Zeid, Maya Abou
A number of vehicle emission models are overly simple, such as static speed-dependent models widely used in
practice, and other models are sophisticated as to require excessive inputs and calculations, which can slow
down computational time. We develop and implement an instantaneous statistical model of emissions (CO2,
CO, HC, and NOx) and fuel consumption for light-duty vehicles, which is derived from the physical loadbased
approaches that are gaining in popularity. The model is calibrated for a set of vehicles driven on standard
as well as aggressive driving cycles. The model is validated on another driving cycle in order to assess its
estimation capabilities. The preliminary results...
8.
Agents to the Rescue? - West, Patricia M.; Ariely, Dan; Bellman, Steve; Bradlow, Eric; Huber, Joel; Johnson, Eric; Kahn, Barbara; Little, John; Schkade, David
The advent of electronic environments is bound to have profound effects on consumer decision making. While the
exact nature of these influences is only partially known it is clear that consumers could benefit from properly
designed electronic agents that know individual users' preferences and can act on their behalf. An examination of
the various roles agents perform is presented as a framework for thinking about the design of electronic agents. In
addition, a set of goals is established that include both outcome-based measures, such as improving decision
quality, as well as process measures like increasing satisfaction and developing trust.
9.
Modeling Traffic Flow Emissions - Cappiello, Alessandra
The main topic of this thesis is the development of light-duty vehicle dynamic emission models and their integration with dynamic traffic models. Combined, these models
constitute fundamental components to support the development and assessment of traffic
management policies, and the optimization of their parameters, to alleviate the negative
impacts of road traffic.
We develop and implement a dynamic model of emissions (CO2, CO, HC, and NOx) and
fuel consumption for light-duty vehicles. The model is derived from regression-based and
load-based emissions modeling approaches, and effectively combines their respective
advantages. The model is calibrated for two vehicle categories using FTP...
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