不完美信息博弈中对手模型的研究

针对传统的显式建模方法依赖大量数据样本的问题,提出了策略自扩展算法,通过样本数据的自扩展来提高建模效率。同时,为了提高对手模型的准确度,结合隐式建模和隐式子策略建模的方法,提出了子策略发现算法。以勒杜克(Leduc)扑克博弈为实验对象,对比研究了2种传统方法和本文提出的2种算法。实验结果表明:策略自扩展算法提高了显式建模的效率和模型准确性。在利用对手弱点获取收益方面,策略自扩展算法比显式建模方法提升了84. 4%,子策略发现算法比隐式建模方法提升了128. 6%。

基于BDI的对手Agent模型

MAS中建立对手模型,并进行意图和规划识别是有效交互的必要条件.BDI是描述思维的有效手段,可用来建立通用的对手思维状态模型.当前对手模型的研究偏重于对单一行为结果的推断,不能充分表示并发多意图及其关系,也不利于实时地的为决策提供支持提出的基于BDI建立通用对手Agent模型的算法改进了AnandS.Rao和Milind Tambe等人有代表性的研究成果.

一个改进的传统协商模型和算法

在传统的AGENT协商方法里,博弈论方法和启发式方法解决了很多复杂的系统问题并且得到了广泛的应用,但是现有的协商模型还过于抽象。通过对对手模型,自身模型和环境模型的相互关系及相应算法的进一步阐述可以较好地解决这一问题,并对发展辩论协商模型和传统协商的实际应用具有帮助。

一种德州扑克牌力评估方法

德州扑克是一种计算机博弈牌类项目,作为不完美信息博弈,其牌力评估较为困难。为了提高针对不同对手的评估效益,提出一种基于对手模型的牌力评估方法。首先用树存储对手的动作频率信息,然后根据树构建一个与对手行动类似的虚拟对手智能体,最后在对局中计算虚拟对手的策略,更新对手的手牌权重,缩小对手可能手牌范围,完成牌力评估。实验结果显示:使用基于对手模型牌力评估方法的智能体击败了不同风格的对手,且总体赢得的筹码比使用静态评估方法的智能体高。与传统方法相比能有效针对不同的对手类型,提高评估效益。

竞争对手分析模型在我国疏浚施工企业的应用

我国疏浚施工建设能力存在供需缺口,随着市场开放度的扩大,国外疏浚企业必然进入我国疏浚建设市场,成为我国疏浚施工企业的竞争对手。应用波特的竞争对手分析模型,对我国疏浚企业的国外竞争对手现行战略和竞争能力进行分析。

QQqq Four-Quark Bound States in Chiral SU(3) Quark Model

Abstract The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU（3） quark model, where Q is the heavy quark （c or b） and q is the light quark （u, d, or s）. We obtain a bound state for the bbnn configuration with quantum number JR=1^＋, I = 0 and for the ccnn （JR=1^＋, I=O） configuration, which is not bound but slightly above the D^＊ D^＊ threshold （n is u or d quark）. Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the ehiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.

Confining Potential Mode in Baryons Spectrum

Based on the flux tube model, the effects of the confining potentials of different configurations, namely the △-type and the Y-type, on the spectra of baryons are studied on SUSF（6） basis. The baryon spectra are obtained in a unified manner. Our result shows that by employing either the △-mode or the Y-mode confining potential, one can achieve reasonable baryon spectra. The △-mode may be mostly effective for the short- and medium-distances, while the Y-mode may offer more contributions to the spectra for long-distances. Although the binding energies in baryon spectra may deviate by a few to several tens MeV for different modes, it is hard to determine either one to be dominant by simply evaluating the baryon spectra. One may need to invoke the baryon decay process to make further judgement.

Effectiveness of 5-flurouracil-based neoadjuvant chemotherapy in locally-advanced gastric/gastroesophageal cancer:A meta-analysis

AIM:To investigate the effectiveness of 5-flurouracilbased neoadjuvant chemotherapy(NAC) for gastroesophageal and gastric cancer by meta-analysis.METHODS:MEDLINE and manual searches were performed to identify all published randomized controlled trials(RCTs) investigating the efficacy of the flurouracilbased NAC for gastroesophageal and gastric cancer,and RCTs of NAC for advanced gastroesophageal and gastric cancer vs no therapy before surgery.Studies that included patients with metastases at enrollment were excluded.Primary endpoint was the odds ratio(OR) for improving overall survival rate of patients with gastroesophageal and gastric cancer.Secondary endpoints were the OR of efficiency for down-staging tumor and increasing R0 resection in patients with gas-troesophageal and gastric cancer.Safety analyses were also performed.The OR was the principal measurement of effect,which was calculated as the treatment group(NAC plus surgery) vs control group(surgery alone) and was presented as a point estimate with 95% confidence intervals(CI).All calculations and statistical tests were performed using RevMan 5.1 software.RESULTS:Seven RCTs were included for the analysis.A total of 1249 patients with advanced gastroesophageal and gastric cancer enrolled in the seven trials were divided into treatment group(n = 620) and control group(n = 629).The quality scores of the RCTs were assessed according to the method of Jadad.The RCT quality scores ranged from 2 to 7(5-point scale),with a mean of 3.75.The median follow-up time in these studies was over 3 years.The meta-analysis showed that NAC improved the overall survival rate(OR 1.40,95%CI 1.11-1.76;P = 0.005),which was statistically significant.The 3-year progression-free survival rate was significantly higher in treatment group than in control group(37.7% vs 27.3%)(OR 1.62,95%CI 1.21-2.15;P = 0.001).The tumor down-stage rate was higher in treatment group than in control group(55.76% vs 41.38%)(OR 1.77,95%CI 1.27-2.49;P = 0.0009) and the R0 resection rate of the gastroesophageal and gastric cancer was higher in treatment group than in control group(75.11% vs 68.56%)(OR 1.38,95%CI 1.03-1.85;P = 0.03),with significant differences.No obvious safety concerns about mortality and complications were raised in these trials.There were no statistically significant differences in perioperative mortality(5.08% vs 4.86%)(OR 1.05,95%CI 0.57-1.94;P = 0.87 fixed-effect model) and in the complication rate between the two groups(13.25% vs 9.66%)(OR 1.40,95%CI 0.91-2.14;P = 0.12 fixed-effect model).Trials showed that patients from Western countries favored NAC compared with those from Asian countries(OR 1.40,95%CI 1.07-1.83).Monotherapy was inferior tomultiple chemotherapy(OR 1.40,95%CI 1.07-1.83).Intravenous administration of NAC was more advantageous than oral route(OR 1.41,95%CI 1.09-1.81).CONCLUSION:Flurouracil-based NAC can safely improve overall survival rate of patients with gastroesophageal/gastric cancer.Additionally,NAC can down the tumor stage and improve R0 resection.

Muon Anomalous Magnetic Moment in the Supersymmetric Models with and Without Right—Handed Neutrinos

We discuss the anomalous magnetic moment of muon in the minimal supersymmetric model with and without right-handed neutrinos. In the same framework, the decay width of is also evaluated. Considering the measured value of muon in the E821 experiment and other experimental constraints on the lepton-flavor-violation processes, we carry out numerical analysis on the concerned observables in the minimal supergravity scenario.

Low-Energy Kπ Phase Shifts in Chiral SU（3） Quark Model

The low-energy region kaon-pion S- and P-wave phase shifts with isospin I = 1/2 and I = 3/2 are dynamically studied in the chiral SU(3) quark model by solving a resonating group method equation. The model parameters are taken to be the values fitted by the energies of the baryon ground states and the kaon-nucleon elastic scattering phase shifts of different partial waves. As a preliminary study the s-channel q(-q) annihilation interactions are not included since they only act in the very short range and are subsequently assumed to be unimportant in the low-energy domain. The numerical results are in qualitative agreement with the experimental data.

Chiral Phase Transition at Finite Isospin Density in Linear Sigma Model

Using the linear sigma model, we have introduced the pion isospin chemical potential. The chiral phase transition is studied at finite temperatures and finite isospin densities. We have studied the μ - T phase diagram for the chiral phase transition and found the transition cannot happen below a certain low temperature because of the BoseEinstein condensation in this system. Above that temperature, the chiral phase transition is studied by the isotherms of pressure versus density. We indicate that the transition, in the chiral limit, is a first-order transition from a low-density phase to a high-density phase like a gas-liquid phase transition.

Ωω States in a Chiral Quark Model

The structures of Ωω states with spin-parity JP= 5/2^-, 3/2^-, and 1/2^- are dynamically studied in both the chlral SU（3） quark model and the extended chiral SU（3） quark model by solving a resonating group method （RGM） equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon （NN） scattering phase shifts, and the hyperon-nucleon （YN） cross sections. The calculated results show that the Ωω state has an attractive interaction, and in the extended chiral SU（3） quark model such attraction can make for a Ωω quasi-bound state with spin-parity JP = 3/2^- or 5/2^- and the binding energy of about several MeV.

Existence of Positive Periodic Solutions of Competitor-Competitor-Mutualist Lotka-Volterra Systems with Infinite Delays

In this paper,the authors primarily explore a delayed competitor-competitor-mutualist Lotka-Volterra model,which is a system of differential equation with infinite integral.The authors first study the existence of positive periodic solutions of the model by using the Krasnoselskii's fixed point theorem,and then present an example to illustrate the main results.

Selection rules of electromagnetic transitions for chirality-parity violation in atomic nuclei

The nuclear Chirality-Parity(ChP) violation, a simultaneous breaking of chiral and reflection symmetries in the intrinsic frame, is investigated with a reflection-asymmetric triaxial particle rotor model. A new symmetry for an ideal ChP violation system is found and the corresponding selection rules of the electromagnetic transitions are derived. The fingerprints for the ChP violation including the nearly degenerate quartet bands and the selection rules of the electromagnetic transitions are provided. These fingerprints are examined for ChP quartet bands by taking a two-j shell h11/2 and d5/2 with typical energy spacing for A = 130 nuclei.