基于演化博弈论的沼肥推广策略研究

我国沼气产业快速发展,由此产生了大量沼液沼渣,若不能及时消纳,将会对环境造成二次污染。大力推广沼肥可以缓解长期过量施用化肥对生态环境造成的不良影响。基于演化博弈理论,该研究根据沼肥推广过程中涉及的主体,构建了政府、沼气工程企业和农户三方演化博弈模型,试图研究在沼肥推广过程中3个主体之间的互动机制,通过博弈分析得出该模型的演化稳定策略。该模型的演化稳定策略为(1,1,1),即政府大力支持沼肥推广,沼气工程企业投资沼肥生产项目,农户选择沼肥是演化稳定策略。结果表明,在沼肥的推广过程中,政府、沼气工程企业和农户的决策行为相互影响,任意一方的演化策略会同时受到其他两方主体演化策略的影响。政府相关政策的实施、沼气工程企业投资沼肥生产项目,需要考虑农户对沼肥的接受程度。农户对沼肥的选择意愿也与政府和沼气工程企业对沼肥的推广程度以及扶持力度有关。该研究结论可以为我国沼肥推广提供参考。     

Actor-Network-Theory perspective on a forestry decision support system design

Use of decision support systems (DSS) has thus far been framed as a social process of adoption or technical process of usability. We analyze the development of a DSS as a process of institutionalization of new as well as drift of existing practices. We write an Actor-Network-Theory (ANT) account, i.e. an interpretive study, that follows the traces left by both human and non-human actors (e.g. technology, methodologies, etc.) to understand how a DSS development project institutionalizes DSS technology in several forest management organizations in the German state of Rheinland Pfalz. The research has an innovative value since it uses ANT in the design of a DSS, hence affecting it, while commonly ANT has been used to understand why networks work or do not. Moreover, we use a new technology (PREZI^TM, www.prezi.com) for the visualization of the whole actor network coherent to the ANT methodology, i.e. “keeping the social flat.” As a result, the development of the ANT account proposed in the present paper, even if still partial, supports the design of new technologies being introduced in current practice and generates an important learning effect thanks to the underpinning interpretative approach.     

Mixing methods – assessment of potential benefits for natural resources planning

Multi-objective forest planning is a multi-methodological endeavor whose success largely depends on how well the combined use of different methods contributes to the goals of the planning. This review assessed the benefits of mixing methods in natural resources planning. A sample of 30 peer-reviewed research articles was analyzed using an evaluation framework, designed based on democracy and planning theories, and participatory planning literature, including four dimensions: transparency, flexibility, consensus building, and operability. According to analyses, mixing different types (i.e. qualitative and quantitative) of methods generally yields greater benefits than the combination of similar methods. The subsample of 12 planning cases that utilized simulation-optimization software (SOS) appeared operable and moderately transparent, whereas flexibility and consensus building were often lacking. In comparison to the wide scholarly discussion on multi-methodology and mixing methods, it was observed that successful mixing examples in natural resource planning are still scarce and there are weaknesses in bridging the methods together. There is an evident need to pursue and to better communicate the benefits of mixing. Some good mixing examples utilizing SOS provided evidence that forest planning processes would make an excellent venue for studying the benefits and caveats of using mixed methods.     

基于多指标区间数关联分析的相对隶属度方法

针对具有区间数的多指标决策问题,借鉴一种逼近于理想点(TOPS IS)分析方法的思想,采用区间数灰色关联度的计算方法,对正、负关联度,利用相对隶属度方法对多方案进行排序,给出了解决区间数多指标决策问题的计算步骤.本文将整个评价方案看作一个整体来寻求正、负理想方案,该方法避免了区间数难以排序的问题,具有可理解性和可操作性.最后给出实例以验证该方法的有效性和实用性.     

Conservation value of dispersed tree cover threatened by pasture management

Trees dispersed in pastures are a prominent feature of many Central American landscapes, particularly in cattle producing regions where farmers retain trees to serve as shade, fodder, timber and firewood. The presence of dispersed trees in pastures is often considered as important for the conservation of biodiversity by providing habitat and enhancing landscape connectivity. However, despite their critical productive and environmental roles, little is known about tree distribution within pastures or how farmers’ management decisions influence the trees themselves and their impact on farm productivity and biodiversity conservation. Here, we present a synthesis of (a) the abundance, composition, and size of dispersed trees in four important cattle producing regions of Costa Rica (Caňas and Río Frío) and Nicaragua (Rivas and Matiguás), based on inventory of 18,669 trees on 1492 ha of pasture, (b) the local knowledge, management and use of trees by cattle farmers, and (c) opportunities for ensuring sustainable management of dispersed trees in pasture-dominated landscapes. Dispersed trees were common in all four landscapes, with mean frequency ranging from 8.0 trees ha⁻¹ in Caňas to 33.4 trees ha⁻¹ in Matiguás. A total of 255 tree species were found in pastures across the four landscapes. The total number of tree species per landscape varied from 72 in Rivas to 101 in Caňas and Rio Frio, with mean species richness per farm ranging from 22.9 in Rio Frio to 45.9 in Matiguás. In all four landscapes, a handful of tree species dominated the pastures, with the ten most abundant species in each landscape accounting for >70% of all trees recorded. Most of these common tree species provide fruits or foliage eaten by cattle, or are important timber or firewood species, and are deliberately retained by farmers for these uses. In all four landscapes, farmers had a detailed knowledge of tree attributes affecting pasture and animal productivity, and influenced tree cover through pasture management activities and occasional tree cutting. Current farm management practices are gradually decreasing the diversity of trees in pastures, and in some cases also tree density, reducing their contribution to farm productivity and biodiversity conservation. To reverse this trend, incentives are required to encourage cattle farmers to retain and enhance tree cover in pastures, through the adoption of pasture management practices that favor the regeneration and persistence of a diverse range of tree species.     

梅里雪山国家公园生物多样性保护规划方法研究

滇西北是中国生物多样性最丰富的地区之一,自2004起,有关部门就开始运用国家公园管理模式对该地区生物多样性进行保护.文章以梅里雪山国家公园为研究对象,对其生物多样性保护的规划方法进行研究.认为保护行动规划方法中的保护对象的确定、威胁因子的分析、制定并实施保护策略、成效评估4个关键步骤是实现国家公园生物多样性保护的有效逻辑方法.     

森林生态系统经营规划决策的研究

以带岭林业局东方红林场森林为例,进行了中、长期的森林生态系统规划决策的研究。在规划中以恢复地带性顶极群落作为经营目标,以各种林分类型向相应的顶极群落演替所需要的相对时间长短作为距离系数建立目标函数。在研究了该区域天然林经营与替模型基础上,把东方红林场森林划分为８个森林经营类型组,分析和定义了决策变量及约束条件。进行线性规划求解。研究结果认为,这种森林规划兼顾森林的经济和生态效益。适应性经营与一体化森林规划体系是控制和纠正这种森林规划风险性的技术手段。     

基于健康安全的棕地再开发决策模型构建及模拟研究——以广东省F市为例

为提高棕地再开发决策的科学性与安全性，以“建设用地准入机制”和“土壤环境质量标准”等为指导思想和标准依据，结合环境、经济、社会和地块特征等因素，构建棕地再开发决策指标体系及决策模型，运用模糊综合法对目标地块拟开发方向进行决策模拟。以广东省F市土壤环境质量调查和土地利用规划数据为基础，结合“三旧改造”规划方案，测算土壤污染程度，采用ArcGIS进行可视化安全评估，对目标地块再开发方向进行决策模拟，并以变动权重组合进行验证。结果表明： 37%的棕地再开发方向需要修正，在各影响因子中，环境因素权重最大，地块特征其次，社会和经济因素最小。研究表明，模拟决策模型确定的土地分级分类风险管控措施对棕地再开发决策具有较好的指导作用。     

Forecasting clinical disease in pigs: comparing a naive and a Bayesian approach

In veterinary practice the clinician often evaluates and predicts herd health status over time according to clinical criteria. In this paper, we modeled three different clinical signs among pigs based on longitudinal clinical observations in 15 pig herds. We compared and discussed the outputs from two different approaches for making clinical forecasts in a herd: a naive approach using a simple time series model with previous disease observations as predictors and a Bayesian state space models approach, in which the time lag variable entered into the random component of the model. We used the Markov chain Monte Carlo technique to calculate posterior distributions of the forecasts. For the herd specific forecasts the results showed that there were only minor differences between the forecasts from the simple time series model and the median forecasts from the Bayesian model. However, the credibility intervals from the Bayesian model were wider than the forecasts from the simple model and, therefore the Bayesian model encompassed the variability in the forecasts better. Compared to the statistical model, the simple time series would be easier to implement in a practical setting. However, the latter lacks the inherent “generality” from the statistical model that allows the user to make statements about the distribution of the herds and to predict disease status based on the “average” correlation among the herds. The applicability of the Bayesian approach within a clinical decision-making framework was discussed, with special emphasis on the use of prior information and clinical forecasting.     

基于Activiti和Drools的水产养殖自动决策流程管理系统

针对目前水产养殖过程管理中缺乏有效的流程化管理、养殖业务规则不明确、养殖决策效率低、人工经验判断操作失误率高等问题,阐述了工作流技术和规则引擎技术结合应用于水产养殖流程管理的设计思想。首先提出了一种基于规则引擎的智能工作流管理系统体系结构,并对系统进行总体框架设计。然后在分析和总结出水产养殖业务流程步骤繁琐不明确、受时间限制、多循环、多并发和存在大量养殖业务决策等特点的基础上,以南美白对虾养殖流程为例,通过Activiti可视化流程设计器对南美白对虾养殖流程进行流程定义和设计,构建水产养殖工作流模型;通过Drools规则引擎制定南美白对虾养殖关键流程业务规则库,制定过程包括养殖规则的分析、定义、设计、编写和触发。最后,将Activiti工作流引擎和Drools规则引擎与当今主流的SSH框架进行整合,开发基于Activiti和Drools的水产养殖自动决策流程管理系统。通过初期试验运行表明,该系统能有效实现水产养殖全流程业务状态的实时监控和养殖关键流程的规则决策,能有效增加养殖产量14.8%,降低饵料系数11.4%,减少人工管理成本30%,使得整体经济效益增加29.3%,初期试验效果良好,为水产养殖信息化过程管理提供了一种切实可行的流程化、自动化、精细化养殖的新策略。