Reachability problem considering running cost

2021 ◽  
Author(s):  
Wei Liao ◽  
Xiaohui Wei ◽  
Jizhou Lai
1994 ◽  
Vol 30 (11) ◽  
pp. 25-33 ◽  
Author(s):  
Yoshimasa Watanabe ◽  
Satoshi Okabe ◽  
Tomochika Arata ◽  
Yuji Haruta

A comprehensive wastewater treatment system that accomplishes oxidation of organic matter, nitrification, and denitrification was developed, and its characteristics and performance were investigated. A municipal wastewater was treated by an up-flow aerated biofilter (UAB), in which biofilms were developed on stainless meshes installed horizontally. This UAB exhibited a great potential ability of oxidation of organic matter, SS stabilization, and nitrification due to a unique aeration mechanism giving high DO concentrations with relatively low aeration rates. Another unique feature of the UAB was that attached biofilms on stainless meshes physically filtered out and/or adsorbed suspended solids in the wastewater in addition to the biological oxidation of organic matter. A stable nitrification could be achieved at HRT=10 hours corresponding to a hydraulic loading of 86 L m−2 d−1 and at a ratio of aeration rate to wastewater flow rate (A/W) of 2, which is considerably low as compared to aeration rates of typical activated sludge systems. This UAB system also could handle relatively high hydraulic loading rates. The UAB used in this study still have enough space to install more stainless meshes so as to reduce hydraulic loading rates resulting in the reduction of HRT and aeration rate, which leads to improvement of the system performance as well as reduction of the running cost.


2018 ◽  
Vol 3 (2) ◽  
pp. 1-6
Author(s):  
Raji A. Abimbola

In recent years, Nigeria’s power generation output from all the available energy sources such as coal, natural gas, and water, is far from the expected number required to meet the energy demand of her teeming populace. This culminates in long hours of power outages frequently experienced in many parts of the country. However, there appears to be no end in sight to the problem. Alternatively, few citizens who can afford generator have wittingly resulted to the use of this device to supply power. Generator set has unavoidable disadvantages of high maintenance or running cost, noise pollution, and release of dangerous gases that pose danger to human lives. Evidently, that solution is risky and inadequate. Power inverter is an alternative and better means of generating electricity with little or no maintenance cost, environment or eco- friendly and poses no risk to human health. It is in that connection that we develop in this work 2KVA sine wave inversion system which produces sinusoidal A.C. signal required in homes for lightning and powering electronic gadgets like television, radio, refrigerator, Air conditioner etc. It is an improvement over square wave and modified sine wave inversion systems that generate digital approximations of A.C. signal. An interesting but new addition is the use of LCD display, interfaced with PIC16F688 microcontroller for showing the design specifications of the inverter.


Author(s):  
Michael Blondin ◽  
Javier Esparza ◽  
Stefan Jaax ◽  
Philipp J. Meyer

AbstractPopulation protocols are a well established model of computation by anonymous, identical finite-state agents. A protocol is well-specified if from every initial configuration, all fair executions of the protocol reach a common consensus. The central verification question for population protocols is the well-specification problem: deciding if a given protocol is well-specified. Esparza et al. have recently shown that this problem is decidable, but with very high complexity: it is at least as hard as the Petri net reachability problem, which is -hard, and for which only algorithms of non-primitive recursive complexity are currently known. In this paper we introduce the class $${ WS}^3$$ WS 3 of well-specified strongly-silent protocols and we prove that it is suitable for automatic verification. More precisely, we show that $${ WS}^3$$ WS 3 has the same computational power as general well-specified protocols, and captures standard protocols from the literature. Moreover, we show that the membership and correctness problems for $${ WS}^3$$ WS 3 reduce to solving boolean combinations of linear constraints over $${\mathbb {N}}$$ N . This allowed us to develop the first software able to automatically prove correctness for all of the infinitely many possible inputs.


Author(s):  
Chris Köcher

AbstractWe study the reachability problem for queue automata and lossy queue automata. Concretely, we consider the set of queue contents which are forwards resp. backwards reachable from a given set of queue contents. Here, we prove the preservation of regularity if the queue automaton loops through some special sets of transformation sequences. This is a generalization of the results by Boigelot et al. and Abdulla et al. regarding queue automata looping through a single sequence of transformations. We also prove that our construction is possible in polynomial time.


2020 ◽  
Author(s):  
Tamás Tóth ◽  
István Majzik

AbstractAlgorithms and protocols with time dependent behavior are often specified formally using timed automata. For practical real-time systems, besides real-valued clock variables, these specifications typically contain discrete data variables with nontrivial data flow. In this paper, we propose a configurable lazy abstraction framework for the location reachability problem of timed automata that potentially contain discrete variables. Moreover, based on our previous work, we uniformly formalize in our framework several abstraction refinement strategies for both clock and discrete variables that can be freely combined, resulting in many distinct algorithm configurations. Besides the proposed refinement strategies, the configurability of the framework allows the integration of existing efficient lazy abstraction algorithms for clock variables based on $${\textit{LU}}$$ LU -bounds. We demonstrate the applicability of the framework and the proposed refinement strategies by an empirical evaluation on a wide range of timed automata models, including ones that contain discrete variables or diagonal constraints.


Author(s):  
H Masding

This paper sets out an assessment of the value and practicality of the construction of fossil fired generating plant designed and built as single units and includes a proposal for the design and layout of a single unit designed to maximize the benefits derived from this concept. The conclusion is that an acceptable design of power plant, based on the construction of single 600 MW units, can be developed for the UK system which could prove to be advantageous in construction time, in capital cost and in running cost. The layout applies equally effectively to large ‘green field’ sites or for replanting existing stations; in addition, the plant can be replicated in detail and thereby reduce design and engineering costs. Finally the layout can also be applied in principle to smaller units for overseas utilities as required by their system developments.


2018 ◽  
Vol 50 (3) ◽  
pp. 671-705 ◽  
Author(s):  
Giorgio Ferrari ◽  
Shuzhen Yang

AbstractIn this paper we study a finite-fuel two-dimensional degenerate singular stochastic control problem under regime switching motivated by the optimal irreversible extraction problem of an exhaustible commodity. A company extracts a natural resource from a reserve with finite capacity and sells it in the market at a spot price that evolves according to a Brownian motion with volatility modulated by a two-state Markov chain. In this setting, the company aims at finding the extraction rule that maximizes its expected discounted cash flow, net of the costs of extraction and maintenance of the reserve. We provide expressions for both the value function and the optimal control. On the one hand, if the running cost for the maintenance of the reserve is a convex function of the reserve level, the optimal extraction rule prescribes a Skorokhod reflection of the (optimally) controlled state process at a certain state and price-dependent threshold. On the other hand, in the presence of a concave running cost function, it is optimal to instantaneously deplete the reserve at the time at which the commodity's price exceeds an endogenously determined critical level. In both cases, the threshold triggering the optimal control is given in terms of the optimal stopping boundary of an auxiliary family of perpetual optimal selling problems with regime switching.


2013 ◽  
Vol 392 ◽  
pp. 791-795
Author(s):  
Lin Zhu ◽  
Hai Zhang

For the characteristics of urban centralized heating system are wide geography coverage and large span of density distribution in the monitoring system but having regular, the paper put forward a remote communication mode combined by WSN and GPRS. As the background of the remote monitoring for the client operating condition in heating network, the paper elaborate the structure of urban remote monitoring system for heating network, and the design idea of its hardware and software. As well as the WSN self-organized protocol is analyzed carefully. The scheme can effectively solve the industrial field problem, which industrial environment is difficult to wire, and the construction and running cost is high in the remote monitoring system. It also has high application value.


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