AbstractThe BATtle of the Attack Detection ALgorithms (BATADAL) is the most recent competition on planning and management of water networks undertaken within the Water Distribution Systems Analysis ...Symposium. The goal of the battle was to compare the performance of algorithms for the detection of cyber-physical attacks, whose frequency has increased in the last few years along with the adoption of smart water technologies. The design challenge was set for the C-Town network, a real-world, medium-sized water distribution system operated through programmable logic controllers and a supervisory control and data acquisition (SCADA) system. Participants were provided with data sets containing (simulated) SCADA observations, and challenged to design an attack detection algorithm. The effectiveness of all submitted algorithms was evaluated in terms of time-to-detection and classification accuracy. Seven teams participated in the battle and proposed a variety of successful approaches leveraging data analysis, model-based detection mechanisms, and rule checking. Results were presented at the Water Distribution Systems Analysis Symposium (World Environmental and Water Resources Congress) in Sacramento, California on May 21–25, 2017. This paper summarizes the BATADAL problem, proposed algorithms, results, and future research directions.
•A system for precise control and prediction of a greenhouse environment was constructed to realize real-time monitoring and intelligent control of soil temperature, air humidity, soil moisture, ...carbon dioxide concentration and light intensity in the artificial environment.•A three-layer feed-forward-back propagation (BP) neural network model was established to access and predict the artificial growth environment of Dendrobium candidum.•The FABPM-BP not only has a reduced network training time but also has improved convergence efficiency and network stability, while the average relative errors are within 5%.
Dendrobium officinale is a perennial epiphytic herb of the Orchidaceae family. It has very strict needs with respect to growth environment and climatic conditions. In order to precisely control the artificial growth environment of Dendrobium candidum, a monitoring system was designed and implemented using a Programmable Logic Controller (PLC) and Supervisory Control and Data Acquisition (SCADA) system.
A platform was created for precise control using a Siemens S7-200CPU224 PLC and different sensors of various environmental parameters as the control unit and SCADA-configured software as the core of the monitoring unit. We here used 4 indexes, soil temperature, soil moisture, humidity, and light, as prediction parameters and established a three-layer feed-forward fuzzy optimization neural network model.
The system not only allows prediction of the optimal environmental parameters for the growth of Dendrobium candidum, real-time monitoring, and intelligent control but also escapes the shortcomings of traditional back-propagation (BP) neural networks, which suffer from slow convergence, shock, and poor generalization. The current model’s average prediction error is less than 2.5%. It also provides a theoretical basis and decision support for the precision control of planting projects and relevant environment forecasting. The climate in the test area is hot and rainy in summer and colder and drier in winter. The annual precipitation is concentrated in spring and summer, peaking twice, in May and October. The subtropical high temperature was recorded in August, which has little rainfall and is prone to drought. Winter features both cold and warm air and some rainy days, but not as much overall precipitation as summer.
Abstract
This project is carried out using Programmable Logic Controller, which is the main component of the proposed system. It is an industrial oriented machine system used to fill water in the ...empty bottles automatically, which reduce the usage of man power, low power consumption, accuracy. The system is implemented in various soft drink industries, water packaging industries and food industries. The filling process gets efficient, when our filling machine is combined with an automatic conveyor to increase the speed of filling process. The conveyor belt roll-up the empty bottles and an analog timer is used to adjust the timing of the water flow. The empty bottles are sensed by photo electric sensors and it detects the empty bottles present in the conveyor, stops the conveyor, then the valve is opened up to fill the bottles. This sequential process will continue for each and every water bottle filling process. A Programmable Logic Controller machine is preferred due to its and cost efficient high ratings. The proposed method will reduce the cost for small scale industries and help them in setting up and an automated decision for filling water bottles.
This paper presents the design and implementation of a multiprocessor programmable controller in field-programmable gate array (FPGA). The novelty of the proposed solution is that it combines two ...approaches used so far in the domain of FPGA implementations of control algorithms, i.e., program based and hardware coded, and applies multiple processors in a single FPGA chip. The controller is programmed according to the IEC 61131-3 standard and runs control tasks in parallel. Performance tests of the prototype show that it is able to execute control programs significantly faster than industrial programmable logic controllers.
Programmable Logic Controller (PLC) programs are vulnerable to tampering attacks with addition of malware, which can substantially cause severe physical destructions. In order to solve the problems, ...We propose a static analysis method of Binary PLC programs for the detection of PLC malwares. Firstly, disassemble the binary program into STL program. Secondly, constructed the control flow graph of STL program according to the characteristics of STL language. Thirdly, generate the program execution paths according to traverse the control flow graph and analysis loop paths. Finally the PLC program output and input mapping relations are obtained based on the program execution paths. The experiment shows that the proposed method has achieved the analysis of PLC programs and get each path predicate and the mapping relation between output and input.
The literature on the subject of synchrophasor estimation (SE) algorithms has discussed the use of interpolated discrete Fourier transform (IpDFT) as an approach capable to find an optimal tradeoff ...between SE accuracy, response time, and computational complexity. Within this category of algorithms, this paper proposes three contributions: the formulation of an enhanced-IpDFT (e-IpDFT) algorithm that iteratively compensates the effects of the spectral interference produced by the negative image of the main spectrum tone; the assessment of the influence of the e-IpDFT parameters on the SE accuracy; and the discussion of the deployment of IpDFT-based SE algorithms into field programmable gate arrays, with particular reference to the compensation of the error introduced by the free-running clock of A/D converters with respect to the global positioning system (GPS) time reference. The paper finally presents the experimental validation of the proposed approach where the e-IpDFT performances are compared with those of a classical IpDFT approach and to the accuracy requirements of both P and M-class phasor measurement units defined in the IEEE Std. C37.118-2011.
Background
The incidence of primary liver cancer (PLC) continues to increase worldwide. The incidence trends and patterns of PLC associated with different age at diagnosis remain unknown.
Methods
We ...collected detailed information on PLC between 1990 and 2017 from Global Burden of Disease Study 2017. Estimated annual percentage changes in the PLC age‐standardized incidence rate (ASR) diagnosed by age, sex, region, and etiology were calculated to quantify the temporal trends in PLC ASR.
Results
Globally, the number of PLC cases for which the age at diagnosis was <30 years decreased from 17,381 in 1990 to 14,661 in 2017, whereas the number of PLC cases diagnosed at age 30 to 59 and ≥60 years old increased from 216,561 and 241,189 in 1990 to 359,770 and 578,344 in 2017, respectively. The ASR of PLC cases with age at diagnosis <30 years and between 30 and 59 years decreased in both sexes, whereas the ASR of PLC with age at diagnosis ≥60 years increased in males and remained stable in females at the global level. Males had a more dramatic increase in PLC diagnosed at age ≥60 years but a milder decrease in PLC diagnosed between 30 and 59 years of age. This decrease was attributed largely to the reduction in PLC caused by hepatitis B and hepatitis C and was consistent in most regions except for developed countries, in which the ASR of PLC increased irrespective of sex and age. The ASR of PLC due to nonalcoholic steatohepatitis (NASH) increased by the greatest magnitude in most regions.
Conclusion
PLC in highly endemic regions has been partly alleviated due to the potent control of hepatitis, especially among young and middle‐aged people. However, an unfavorable trend was observed in most developed countries and in elderly populations. As such, PLC prevention schedules should give more attention to NASH and elderly patients.
There is a significant increase in incidence of late‐onset liver cancer. The most pronounced increase occurs in liver cancer due to nonalcoholic steatohepatitis.
This brief presents an approach to safe controller synthesis for manufacturing systems controlled by programmable logic controllers (PLCs). In this brief, manufacturing systems are considered as ...discrete-event dynamic systems with logical inputs and outputs. The methodology is based on the use of safety constraints placed at the end of the PLC program. These constraints are checked offline by a formal approach and acted as a safety filter in order to be robust against control errors. The proposed approach separates the functional control part from the safety part and focuses on the latter. This brief presents the whole methodology and recent improvements on consistency checking of a set of Boolean expressions.
One solution to problems with petroleum derived plastics is to design polymers for the circular economy. In this regard, polymer chemistries, like ester or carbonate linkages, which are closer to ...equilibrium are very promising but to use these materials requires improvements to their properties and methods of manufacture. Here, efficient polymerization catalyses are used to transform wastes and bio-sourced monomers into thermoplastics which combine high elasticity and strength and which can be degraded to allow for some chemical recycling. The plastics are prepared from carbon dioxide, limonene oxide (from waste citrus fruit peel) and ε-decalactone (from triglycerides). These monomers are polymerized, using catalyzed controlled polymerizations with high conversion efficiencies, to selectively form ABA block polymers (A = high T g polycarbonate, B = low T g polyester). The series of 5 poly(limonene carbonate)- b -poly(ε-decalactone)- b -poly(limonene carbonate) (PLC-PDL-PLC) samples allow for systematic variations in the overall molar masses ( M n = 50–100 kg mol −1 ) and hard-block compositions (21–63 wt% PLC). All the polymers are fully characterized using a range of spectroscopies, gel permeation chromatography, thermal and tensile mechanical measurements. The leading plastic combines tensile strength (stress at break, σ b = 21.2 MPa, Young's Modulus, E y = 321 MPa) and high elasticity (elongation at break, ε b = 400%) – an enhancement of more than 20× in elongation at break and tensile toughness over poly(limonene carbonate), overcoming the well-known brittleness and processing limitations of PLC. It undergoes selective, catalyzed depolymerization to limonene oxide, carbon dioxide and the precursor polyester providing a future chemical recycling and upcycling opportunity.
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