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The imbalanced development among different levels of healthcare facilities has become a major social issue in China's urban healthcare system. In this research, we propose a methodology to find the optimal macro-level patient flow distribution in terms of multi-dimension inputs and outputs for the hierarchical healthcare system. This research integrates Discrete-Event Simulation (DES), multi-objective...
The block relocation problem, which is also known as the container relocation problem, is to find an optimal sequence of operations for retrieving blocks (containers) from a container bay composed of several stacks. The primary contribution of this study is that a lower bound better than those in the existing studies is proposed. This enables us to construct a faster branch-and-bound algorithm than...
Steady state analysis of production systems have been extensively studied during the past several decades. This type of analysis is usually applicable in large-volume manufacturing as the transient can be ignored compared to the overall production run-time. However, when the volume of the production is relatively small, transient may play a major role during the production process and steady state...
Introduction of robots into manual assembly lines to assist human workers or introduction of human into robot-based manufacturing attracts more and more attention in academy and industry. This interest stems from the insight that the integration of robots into manual assembly lines or vice versa may increase productivity by combining the abilities of machines with those of humans. To uphold productivity...
Geometric fidelity of 3D printed products is critical for Additive Manufacturing (AM) or 3D printing to be a direct manufacturing technology. Shape deviations of AM built products can be attributed to multiple variation sources such as substrate geometry defect, disturbance in process variables, and material phase change. Three strategies have been reported to improve geometric quality in AM: (1)...
This paper presents the development and validation of an automatic steering controller that has been successfully implemented on a 18.3-m articulated bus for revenue service in Eugene, Oregon, USA. The automated steering system provides both lane keeping and S-curve precision docking on a 4-km-long narrow and curving urban segment with six stations and mixed traffic lanes while the operator controls...
An extensible, decentralized Internet of Things (IoT), with self-governing objects connected to a shared, variable power supply, is a realistic problem domain for certain demand-management problems arising in the context of future “smart homes” connected to smart power grids. A theoretical framework of such an IoT is presented and discussed in this paper. Each object of the IoT has a power demand...
This paper deals with the description of pilot operational work of the system for heat energy collection from thermally active mining dump Hedvika. It describes particular technologies for heat collection including the system for use of the gathered heat energy in the form of hot water. It also describes the measurement system that monitors thermal activity of the mining dump at the location of heat...
In this paper, we propose a multi-agent based electric power interchange method between micro-grids (MGs). The proposed multi-agent system consists of eight types of agent: single micro virtual power plant agent (MVPP), single Micro Grid controller agent (MGC), Load agents (LAGs), gas-turbines (gas-engine) agents (GAGs), photovoltaic generation agents (PVAGs), wind-turbine generation agents (WTAGs),...
This paper presents a method for semi-automatically segmenting ion-abrasion scanning electron microscopy (I-A SEM) images of fuel cell anodes into discrete regions representing the metal, ceramic, and empty space components of a given volume of a fuel cell anode. Segmentation is accomplished by the use of the fast marching method (FMM) proceeding from multiple automatically-generated seeds. Statistical...
The engine cooling system in trucks is one of the main sources of parasite load. Thus fuel efficiency can be improved by optimal control of engine thermal management system considering fuel consumption minimization as the objective. Although several optimal control methods have been proposed for the engine cooling system, their main emphasize is on regulating engine and coolant temperature in an acceptable...
Use of renewable energy sources for electricity generation is gaining prominence due to the increasing importance of sustainable development. Many of the electricity producers using renewable energy resources have very small generating capacities and it is a challenge to integrate them with the grid. Smart grids can play an important role in facilitating integration of these small distributed electricity...
A multi-cluster tool is composed of a number of single-cluster tools linked by buffering modules. The capacity of a buffering module can be one or two. Aiming at finding an optimal one-wafer cyclic schedule, this work explores the effect of two-space buffering modules on the performance of a multi-cluster tool. The tool is modeled by a kind of Petri nets. The dynamic behavior of robot waiting and...
This work investigates the challenging problem of scheduling single-arm multi-cluster tools with wafer residency time constraints. They have linear topology and their bottleneck tool is process-bound. This work aims to find an optimal one-wafer cyclic schedule. With a prior developed Petri net model and the minimal cycle time for a multi-cluster tool without wafer residency time constraints, it derives...
Semiconductor wafer fabrication facility (fab) is a typical re-entrant manufacturing system. It is characterized with reentrant process flows, mix processing models, large-scale and unbalanced production facilities. A hybrid method (ACO-ICSA), combining an ant colony optimization (ACO) with immune clone selection algorithm (ICSA), is proposed to solve its fab-wide scheduling problem. Its main idea...
Scheduling optimization in semiconductor manufacturing is always a crucial task in production performance indicators such as machine utilization, cycle time and delivery times. With the increasing complexity of fabrication techniques and scales, scheduling and control activities are inevitably confronted with each other and shall be integrated correspondingly. In particular scheduling and control...
This paper considers a semiconductor manufacturing scheduling problem (SMSP), subjected to all the practical constraints such as limited waiting time, machine status, different process time on different machines, setup time and arrival time in wafer fabrication facilities (fabs) of semiconductor manufacturing industry. A hybrid estimation of distribution algorithm with multiple subpopulations (HEDA-MS)...
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