Strict Minimal Siphon-Based Colored Petri Net Supervisor Synthesis for Automated Manufacturing Systems With Unreliable Resources

Various deadlock control policies for automated manufacturing systems with reliable and shared resources have been developed, based on Petri nets. In practical applications, a resource may be unreliable. Thus, the deadlock control policies proposed in previous studies are not applicable to such applications. This paper proposes a two-step robust deadlock control strategy for systems with unreliable and shared resources. In the first step, a live (deadlock-free) controlled system that does not consider the failure of resources is derived by using strict minimal siphon control. The second step deals with deadlock control issues caused by the failures of the resources. Considering all resource failures, a common recovery subnet based on colored Petri nets is proposed for all resource failures in the Petri net model. The recovery subnet is added to the derived system at the first step to make the system reliable. The proposed method has been tested using an automated manufacturing system deployed at King Saud University.publishedVersio

Petri Nets at Modelling and Control of Discrete-Event Systems with Nondeterminism - Part 2

Discrete-Event Systems (DES) are discrete in nature. Petri Nets (PN) are one of the most widespread tools for DES modelling, analyzing and control. Different kinds of PN can be used for such purposes. Some of them were described in [3], being the first part of this paper. Here, the applicability of Labelled PN (LbPN) and Interpreted PN (IPN) for modelling and control of nondeterministic DES, especially with uncontrollable and/or unobservable transitions in the models, will be pointed out. Moreover, another kinds of nondeterminism in DES (errors, failures) will be modelled, and the possibilities of the error recovery of failed system will be presented

Design and Management of Manufacturing Systems

Although the design and management of manufacturing systems have been explored in the literature for many years now, they still remain topical problems in the current scientific research. The changing market trends, globalization, the constant pressure to reduce production costs, and technical and technological progress make it necessary to search for new manufacturing methods and ways of organizing them, and to modify manufacturing system design paradigms. This book presents current research in different areas connected with the design and management of manufacturing systems and covers such subject areas as: methods supporting the design of manufacturing systems, methods of improving maintenance processes in companies, the design and improvement of manufacturing processes, the control of production processes in modern manufacturing systems production methods and techniques used in modern manufacturing systems and environmental aspects of production and their impact on the design and management of manufacturing systems. The wide range of research findings reported in this book confirms that the design of manufacturing systems is a complex problem and that the achievement of goals set for modern manufacturing systems requires interdisciplinary knowledge and the simultaneous design of the product, process and system, as well as the knowledge of modern manufacturing and organizational methods and techniques

18th Annual Symposium of the School of Science, Engineering and Health

Message from the Dean We in the School of Science, Engineering and Health welcome you to this 18th Annual Symposium, and our first as Messiah University. Here you will see our students, faculty and staff showcase innovation, creativity, teamwork and professionalism in our academic departments. Basic and applied research in science and health fields stem from curiosity, acquired skill, and a desire to test and improve processes from foundational principles. The outcomes of scientific research expand intellectual understanding and have tremendous impact on quality of life, environmental health, and human flourishing. We miss having you as guests on our campus but warmly welcome you to enjoy this day virtually. Angela Hare Dean School of Science, Engineering and Health, Messiah Universit

USCID water management conference

Presented at Upgrading technology and infrastructure in a finance-challenged economy: a USCID water management conference held on March 23-26, 2010 in Sacramento, California.Includes bibliographical references.The Surface Energy Balance Algorithm for Land (SEBAL®) is used worldwide to estimate actual evpotranspiration (ET) at different spatial scales (individual fields to entire basins) and temporal scales (water year, growing season, individual day, etc.). SEBAL has been successfully applied on various surface types including crops, riparian, natural vegetation, playas, and wetlands. Comparisons of SEBAL actual ET results with reliable ground based measurements (Eddy covariance, Bowen ratio, lysimeter, water balance and scintillometer) have shown close agreement with differences ranging from 1 to 5% when compared to reliable ground-based estimates over a growing season when the model is applied by experienced operators. This paper describes near real-time application of SEBAL® (Version 2009) to produce weekly maps of actual ET, crop coefficients, and biomass production for California's Central Valley. Each week, the maps for the prior week are produced and posted to the Internet. The maps are developed using MODIS multispectral satellite imagery with an end resolution of 250 meters. This paper discusses potential application of near real time actual ET maps by water managers, water supply agencies and irrigators

Advances in Robotics, Automation and Control

The book presents an excellent overview of the recent developments in the different areas of Robotics, Automation and Control. Through its 24 chapters, this book presents topics related to control and robot design; it also introduces new mathematical tools and techniques devoted to improve the system modeling and control. An important point is the use of rational agents and heuristic techniques to cope with the computational complexity required for controlling complex systems. Through this book, we also find navigation and vision algorithms, automatic handwritten comprehension and speech recognition systems that will be included in the next generation of productive systems developed by man

USCID water management conference

Presented at Upgrading technology and infrastructure in a finance-challenged economy: a USCID water management conference held on March 23-26, 2010 in Sacramento, California.Includes bibliographical references.The operation of main irrigation canals is complicated in situations where the operator does not have full control over the canal inflow, or where there are very long transmission distances from the point of supply, or both. Experienced operators are able to control the canal, but often supply errors are simply passed to downstream, thus creating problems further down the system. In previous work, the senior author showed that it is important to contain such errors and not let them pass downstream. With automatic upstream level control, all flow errors are passed to the downstream end of the canal. Distant downstream water level control requires full control of canal inflow. Without this, most errors will occur toward the upstream end of the canal. An alternative scheme is offered here where the canal check gates are controlled based on the relative water level error between adjacent pools. The scheme uses a simple linear model for canal pool response. The scheme is implemented as a multiple-input, multiple-output scheme and solved as a Linear Quadratic Regulator (LQR). Thus all gates respond to relative deviations from water-level set point. The scheme works to keep the relative deviations in all pools the same. If the canal has more inflow than outflow, the scheme will adjust gates so the water levels in all pools will rise together with the same deviation from set point. It thus distributes the error over the entire canal. When in equilibrium, operators will be able to judge the actual flow rate mismatch by the rate of change of these levels. The scheme acts like a combination of upstream level and distant downstream level control. It was tested on a simulation model of the Central Main Canal at the Central Arizona Irrigation and Drainage District, Eloy, AZ

USCID water management conference

Presented at Upgrading technology and infrastructure in a finance-challenged economy: a USCID water management conference held on March 23-26, 2010 in Sacramento, California.Includes bibliographical references.The Central Arizona Irrigation and Drainage District (CAIDD) began delivering water to users in 1989. Although designed for automatic control, the system was run manually until a homemade SCADA (Supervisory Control and Data Acquisition) system was developed by district employees. In 2002, problems with radio communication and limitations of the homemade SCADA system prompted CAIDD to begin the process of modernization. New spread-spectrum radios and RTUs (Remote Terminal Units) were purchased along with a commercial SCADA package (iFix by GE-IP). In 2005, CAIDD decided to pursue implementation of full automated control of a majority of district check gates. Currently, 125 gates are under remote manual supervisory control and 129 water levels are remotely monitored. CAIDD chose to implement SacMan (Software for Automated Canal Management) under development by the U.S. Arid Land Agricultural Research Center, Maricopa, AZ. The decision was made to only apply full automation at gates that had gate position sensors. Thus purchase and installation of gate position sensors have slowed implementation. To date, five lateral canals have been set up for full automatic control, where SacMan routes flow changes through the canal and uses downstream water level feedback control to correct for any errors that occur. The ditchrider only makes changes at the farm turnouts and district-operated wells. Automation of the Central Main canal has been tested in simulation. Control of this canal requires special treatment, as described in a companion paper. The district is waiting until enough of the canal is ready for automation before it turns automatic controls on 24/7, since this will require some operator training and remote oversight when problems occur. We hope this occurs in the summer of 2010

USCID water management conference

Presented at Upgrading technology and infrastructure in a finance-challenged economy: a USCID water management conference held on March 23-26, 2010 in Sacramento, California.Glenn-Colusa Irrigation District (GCID) is in the process of developing a Resources Plan (Plan) to establish improved policies and decision making processes to better and more actively manage its available water supplies. The first element of the Plan will address Water Supplies and Transfers; it will be developed through evaluation of the district's recent historical and future water demands relative to available surface water and groundwater supplies. The analyses will reveal the probabilities, magnitudes and durations of possible future water supply shortage and surplus conditions. When combined with supporting legal and institutional review, the analyses will provide a basis for managing available water surface and groundwater supplies, shaping conjunctive water management policy, and evaluating potential surface water transfers. GCID is developing a water balance model, including related refinements to the District's water measurement, data management and reporting systems, to analyze historical and possible future water supplies and demands. The water balance will be calculated on a monthly time step for up to ten consecutive years, including winter months when rainfall is appreciable and irrigation demands are generally low. Individual water balances will be prepared for each of GCID's ten water operator areas, which can be combined to form the balance for the overall District. This paper provides a background description of GCID and discusses ongoing development of the water balance model and related improvements to GCID's flow measurement and data management procedures

USCID water management conference

Presented at Upgrading technology and infrastructure in a finance-challenged economy: a USCID water management conference held on March 23-26, 2010 in Sacramento, California.Due to multiple impacts being placed on the James Irrigation District (District) water supply, a study was performed to understand if the District could sustain its current operations. It was determined that the practices could continue but it would require capitally intensive improvements to the Districts infrastructure. Planned improvements include the construction of recharge basins for sustainability, installation of up to 16 groundwater wells and pumps, basin construction, pipeline installation, and construction of flow control and pumping structures. The improvements were estimated to cost approximately $9,000,000; a cost too high for the District to fund on their own. Because of the urgency of the project, The District explored multiple opportunities to fund the project. This included applying for loans, applying for grants, raising water rates, and raising land assessments; all at the same time. To obtain loan money the District applied for funds through Proposition 82, distributed by the Department of Water Resources (DWR). At this same time, the district pursued loans through local banks, which provided a challenge considering the unstable banking industry. Many components of the project are proposed to be built using grant funding. First was a Challenge Grant as provided by United States Bureau of Reclamation's (USBR) Water 2025 program; providing$300,000. Next was the USBR Field Services program; providing $25,000. Approximately$50,000 was utilized from the DWR Local Groundwater Assistance Program. In addition to these funds, Recovery Act funding became available for drought relief, where the District could obtain roughly $1,500,000. To generate further income the District approved a water rate increase. It was at this time when it became apparent that the Districts revenue source had become out of balance. The Land assessments were not enough to cover the operational overhead of the District. To rectify this issue, land assessments would need to be raised. This would require a proposition 218 election, which has been pursued. The intention of this paper is to discuss the multiple funding sources available to the District, how they were utilized, and problems that have been encountered