Feed costs are the largest expense in commercial beef production. Increasing cattle (Bos taurus) feed efficiency should reduce feed costs and increase beef profitability. This study used data from ...two years of a backgrounding trial conducted in Lacombe, Alberta, Canada. The evaluation looked at economic and predicted CH4 emission impacts of diet quality and cattle efficiency type in backgrounding systems. The hypothesis was that diet quality from use of barley (Hordeum vulgare c.v. Canmore) or triticale (xTriticosecale c.v. Bunker) silage-based diets and cattle efficiency type defined by residual feed intake would interact to affect profitability and CH4 emissions. Effects of diet and cattle efficiency type on profitability and CO2e emissions were assessed using statistical and stochastic risk simulation. The profitability of beef backgrounding was affected by cattle efficiency type and diet quality with higher quality barley silage also lowering CO2e emissions. The difference in certainty equivalent (CAD~30 steer−1) of efficient steers on barley silage and inefficient steers on barley silage or efficient or inefficient steers on triticale silage supports a beef backgrounding producer focus on diet quality and cattle efficiency type. This study did not address potential agronomic differences, including yield, which could provide nuance to forage choice.
This paper investigates the decision planning problem of a quadrotor in dynamical environment where there are moving target robots that are ready to be driven into an aim area by turn commands from ...the quadrotor. First, a model of the decision planning problem is formulated. Second, a searching based planning algorithm is proposed for the quadrotor to determine when and where to command which target robot. A pruning function is designed in the proposed algorithm to guarantee that the obtained decision sequences are feasible. Guard conditions are set to avoid decision oscillation. Simulation results are provided to show the effectiveness of the proposed algorithm.
Learning algorithm design and applications of state-based games are investigated. First, a heuristic uncoupled learning algorithm, which is a two memory better reply learning rule, is proposed. Under ...reachability conditions it is proved that for any initial state, if all agents in the state-based game follow the proposed learning algorithm, the action state pair converges almost surely to an action invariant set of recurrent state equilibria. The design of the learning algorithm relies on global and local searches with finite memory, inertia, and randomness. Then, existence of time-efficient universal learning algorithm is studied. Finally, applications of our proposed learning algorithm are discussed, including learning pure Nash equilibrium in finite games and cooperative control with time-varying communication structure.
Logical dynamic games (LDGs) are a class of dynamic games that incorporate logical dynamics to describe the evolution of external states. Such games can be found in a wide range of natural and ...engineered systems, such as the Boolean network of lactose operon in Escherichia coli . However, little attention has been paid to LDGs in the control community. This paper aims at developing a framework for the analysis and synthesis of LDGs under finite-horizon criteria. First, a general mathematical model of LDGs is constructed. Using dynamic programming theory, we prove that an LDG can be decomposed as a series of time-sliced static games, and the existence of pure dynamic Nash equilibrium (DNE) is proved to be equivalent to the existence of pure Nash equilibria of the decomposed time-sliced static games. To disentangle the circular dependency in the DNE calculation, a backward recursive method is proposed. Second, the concept of logical dynamic potential games (LDPGs) is proposed, and the connection between an LDG and its corresponding optimal control problem is established. Three verification conditions for a given LDG to be LDPG are presented, including time-sliced condition, closed-path condition, and potential equation condition. And a recursive algorithm is further designed for the verification of LDPGs via potential equation conditions. Third, to seek time-independent verification conditions, LDGs with action-independent transition properties are investigated. We prove that, if the auxiliary game constructed by the stage cost function is a state-based potential game, then the LDG is an LDPG. Finally, the effectiveness of the theoretical results is demonstrated by some numerical examples.
This study focuses on the problem of asymptotical stabilization of logic dynamical systems (LDSs) under the situation where the only available measurable information is the real-time output. We ...propose a novel time-invariant control strategy called output-based random control (OBRC), which breaks through the limitation of time-invariant deterministic output feedback (TIDOF). The TIDOF can be regarded as a special type of the OBRC, but the OBRC is capable of stabilizing some LDSs that cannot be stabilized by any TIDOF. A necessary and sufficient condition for asymptotical stabilizability by the OBRC and a method of finding an optimal OBRC that minimizes a quadratic cost function are proposed. The proposed OBRC was applied to a reduced gene network for the lac operon in the bacterium Escherichia coli . The results of numerical computations and time-domain simulations indicate that the OBRC outperforms the TIDOF.
Block copolymerization of vinyl acetate (VAc) and vinyl neo-decanoate (VNDc) is carried out in the presence of a disulfide, isopropylxanthic disulfide (DIP), using 2,2′-azoisobutyronitrile (AIBN) as ...the radical initiator. The polymerization proceeds in a controlled/“living” style, as illustrated by stepwise increase in molecular weight and relatively narrow molecular weight distribution of the final product. The reaction mechanism is investigated in detail for the system of VAc homopolymerization in the presence of DIP. The results of chromatography, NMR, and mass spectra reveal that there exists two kinds of RAFT agents, that is, S-(cyano)isopropyl O-isopropyl xanthate and diisopropyl dithiocarbonate, the former coming from the reaction of 2-cyano-isopropyl radical with DIP and the latter being formed in situ during a series of radical process participated by the monomer. High efficiency of the cross initiation is achieved for the sequential polymerization. The block lengths are well controlled by the ratio of monomer to RAFT agents. The resulting block copolymer, PVAc-b-PVNDc, is hydrolyzed to prepare PVOH-b-PVNDc. These block copolymers, before and after hydrolysis, undergo self-assembly in solution and phase separation in bulk state.
To improve the de-noising effects of low signal-to-noise ratio (SNR) nuclear magnetic resonance (NMR) log echo data, this paper applies the wavelet packet threshold algorithm to the data. The ...principle of the algorithm is elaborated in detail. By comparing the properties of a series of wavelet packet bases and the relevance between them and the NMR log echo train signal, 'sym7' is found to be the optimal wavelet packet basis of the wavelet packet threshold algorithm to de-noise the NMR log echo train signal. A new method is presented to determine the optimal wavelet packet decomposition scale; this is within the scope of its maximum, using the modulus maxima and the Shannon entropy minimum standards to determine the global and local optimal wavelet packet decomposition scales, respectively. The results of applying the method to the simulated and actual NMR log echo data indicate that compared with the wavelet threshold algorithm, the wavelet packet threshold algorithm, which shows higher decomposition accuracy and better de-noising effect, is much more suitable for de-noising low SNR-NMR log echo data.
Taking the Triassic Chang 7 Member tight reservoirs of the Yanchang Formation in the Ordos Basin as study object, transverse relaxation simulation was made using nuclear magnetic resonance (NMR) ...experimental data, CT images and random-walker algorithm to evaluate microscopic pore-throats of the tight reservoirs. The smoothing degree of well logging curves was utilized to evaluate sand structure of the tight reservoirs; and through multi-well analysis and the calibration of well testing data, a grading chart of tight reservoir productivity was established based on sand structure. Reservoir quality was judged and analyzed by pore level: Transverse surface relaxivity ρ2 was obtained by comparing transverse relaxation time T2 of numerical simulation and that of NMR experiment, and the distribution of pore-throat radius was obtained according to the corrected NMR logging curves. The study shows there is an obvious correlation between productivity and sand structure of Chang 7 tight reservoirs. The more homogeneous the distribution of lithology, physical property and oiliness of the massive sand, and the smoother the well logging curves, the more likely the high oil yield will occur. Based on well logging evaluation and grading chart of productivity of tight reservoirs, sweet spots in well area W of Jiyuan Oilfield in Ordos Basin were identified, the comparison of the evaluation results and well testing data shows the accuracy rate is as high as 94.7%.
This paper investigates zero-determinant (ZD) strategies for iterated multi-player multi-action games with multiple memories. First, using the semi-tensor product (STP) of matrices, an equivalent ...algebraic model for the iterated game is proposed. Based on the algebraic expression, ZD strategies are derived for repeated finite games with multiple memories, allowing players to unilaterally apply a linear relationship among their augmented expected payoffs regardless of their opponents’ strategies. Furthermore, ZD strategies for repeated symmetric and skew-symmetric games are considered, based on which the coupling correlations among players’ payoffs, as well as the structure of the payoff vectors, are clarified. It is found that in repeated symmetric games, any player can get the same augmented expected payoff by employing a ZD strategy. In repeated skew-symmetric games, it is possible for all participants to achieve a zero-sum outcome. To execute the aforementioned ZD strategies, some identical elements are required in each augmented payoff vector for symmetric games, whereas the payoff vector for skew-symmetric games must contain zero elements.
As a small-scale power system, microgrid (MG) will lose support from the main grid if it switches to islanded mode because of the pre-planned scheduling or unplanned disturbances. To synchronise the ...frequency and voltage to their reference values, a secondary frequency and voltage cooperative control is proposed in this study. The proposed secondary control can synchronise the frequency and voltage to their reference values in finite time and achieve the active power sharing simultaneously. Moreover, it is suitable for switching communication architecture. The MG is considered as multi-agent systems and the system stability is proved by multi-agent theory and finite-time stability theory. A simulation system is established in Matlab/Simulink environment, and the results show the effectiveness of the proposed controller.
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