基于CC的防火墙安全功能分析   总被引：1，自引：0，他引：1  

梁思  刘嘉勇  胡勇  陈波 《成都信息工程学院学报》2006,21(4):519-522

防火墙是网络安全的核心手段。依据基于CC（Common Criteria）制订的国家标准——包过滤防火墙安全技术要求和应用级防火墙安全技术要求，提出每项安全功能要求对应的实际安全措施，并分析当前防火墙未实现的安全功能要求。  相似文献   

青藏高原地区不同下垫面陆面过程的数值模拟研究   总被引：4，自引：0，他引：4  

李燕  刘新  李伟平 《高原气象》2012,31(3):581-591

利用陆面过程模式Common Land Model(CoLM),选取青藏高原上3个不同下垫面观测站(藏东南站、纳木错站和珠峰站)的观测资料,对这3个野外观测站进行了单点数值模拟试验。根据3个测站的试验数据,对模式中土壤孔隙度和饱和导水率进行了优化,针对青藏高原地区土壤层薄的特点,对模式中土壤分层方案进行了调整。结果表明,调整分层方案后的CoLM模式对3个测站土壤湿度的模拟性能较原分层方案有明显提高,平均偏差均减小0.014以上。但是与观测值相比,藏东南站土壤湿度的模拟整体偏低,纳木错站和珠峰站则整体偏高。对土壤温度而言,3个测站模拟与观测的相关系数都达到了0.9以上,珠峰站偏差较大,调整分层方案后模拟的偏差有一定的改进。模式较好地模拟了3个测站的净辐射、感热通量和潜热通量的日变化和季节变化情况,调整分层方案后潜热通量的改进最为明显。  相似文献   

CoLM模式对青藏高原中部BJ站陆面过程的数值模拟   总被引：8，自引：2，他引：6  

罗斯琼  吕世华  张宇  胡泽勇  马耀明  李锁锁  尚伦宇 《高原气象》2008,27(2):259-271

利用公共陆面模式Common Land Model(CoLM)及"全球协调加强观测计划之亚澳季风青藏高原试验"(CAMP/Tibet)中那曲地区Bujiao(BJ)站2002—2004年的观测资料对该地区进行了单点数值模拟试验。通过比较模拟与观测的地表能量通量,表明CoLM较成功地模拟了该地区的能量分配。模式对向上的短波辐射、向上的长波辐射、净辐射及土壤热通量模拟得较好,但冬季存在偏差。进一步比较了模拟和观测的土壤温度及土壤湿度,发现浅层60 cm土壤温度模拟较好,深层存在偏差,表现为土壤温度变化滞后于实际变化。土壤湿度总体偏小,尤其是冬季冻结期,土壤冻融过程中忽略了土壤液态水在温度0℃以下仍能存在,含冰量模拟偏高。  相似文献   

Finding common ground? Spaces of dialogue and the negotiation of Indigenous interests in environmental campaigns in Australia   总被引：5，自引：0，他引：5  

Jenny Pickerill 《Geoforum》2009,40(1):66-79

Critiquing the usefulness of cosmopolitanism this paper argues that we need a more nuanced and subtle understanding of how commonalities are found, created and maintained across difference. This paper uses two juxtapositions of perspective (around place and environment) to explore how such boundaries of difference can be negotiated. It uses an examination of the ways in which environmental groups in Australia have sought to negotiate Indigenous interests through creating spaces of dialogue and changing working practices. It is based on 30 interviews with both Indigenous and non-Indigenous activists across two case regions; Cape York (Queensland) and Barmah-Millewa (Victoria/New South Wales). Four issues were identified that have proved particularly contentious in negotiations to build collaborative campaigns: language; power and ownership; scale and timeframes; and economics. There are examples of both successes and ongoing problematic practices across these tensions. However there is also a growing mutual ownership of the issues. Moving beyond a colonial paternal sense of responsibility, to a dynamic and engaged mutuality of concern for both processes and outcomes has resulted in gradual, small, and progressive steps forward in Indigenous/non-Indigenous collaborative environmental campaigning.  相似文献   

Objectives of fisheries management: case studies from the UK, France, Spain and Denmark     

Simon Mardle  Sean Pascoe  Jean Boncoeur  Bertrand Le Gallic  Juan J. García-Hoyo  Ins Herrero  Ramon Jimenez-Toribio  Concepcin Cortes  Nuria Padilla  Jesper Raakjaer Nielsen  Christoph Mathiesen 《Marine Policy》2002,26(6)

The main objectives of fisheries management are generally similar throughout the world. These are often stated in policy documents such as the Common Fisheries Policy and the Magnuson–Stevens Fishery Conservation and Management Act. However, at the local level often the key objectives of management are more detailed, characterised by both the overriding management structure and the status and type of fishery concerned. In this paper, we consider case study fisheries from the UK, France, Spain and Denmark to compare some of the various types of fisheries and fisheries management systems that exist in the European Union. From this, we define the key objectives for each management system.  相似文献   

Flexible management of fishing rights and a sustainable fisheries industry in Europe   总被引：3，自引：0，他引：3  

Steffen Hentrich  Markus Salomon   《Marine Policy》2006,30(6):712-720

Although overexploitation of commercial fish stocks in European waters has been in the public debate now for more than 20 years, the European Union has so far failed to implement sustainable fisheries management. Millions in subsidies paid to the fishing industry have led to significant excess capacity in the fishing fleet. Various feeble attempts to stop overexploitation of marine resources have failed. The cause is that fishing policy is highly dominated by short-term socioeconomic interests. There is an urgent need for a new fisheries management system in Europe that supports reductions in the fishing fleet, increases responsibility among fishers and guarantees long-term conservation of natural marine resources.Transferable rights to fish have proved a reliable and effective means of creating incentives to conserve marine resources. By strengthening individual fishing rights under flexible quota management systems, the EU Member States could, within the Common Fisheries Policy, make a significant contribution to conserving fish stocks, to reducing excess capacity and to raising the profitability of the fisheries industry. A closer look at existing reservations against a flexible management system shows most of the objections to be overstated or capable of resolution.  相似文献   

CoLM模式对塔克拉玛干沙漠北缘陆面过程模拟评估及修正   总被引：1，自引：1，他引：0  

金莉莉  李振杰  何清  刘永强  买买提艾力&#  买买提依明  辛渝 《中国沙漠》2018,38(6):1287-1302

采用2011年3月22日至7月26日肖塘陆气相互作用观测资料测试了不同陆面参数对公共陆面模式（CoLM）模拟效果的影响。地表参数包括地表反照率（α）、地表比辐射率（ε）、空气动力学和热力学粗糙度（z_0m、z_0h）、零置位移（d）、热传输附加阻尼（kB^-1）。结果表明：感热通量H和地表温度T_g对地表反照率、动力学粗糙度和地表比辐射率比较敏感,对零置位移不敏感。通过观测资料获得的这些参数及kB^-1参数化方案均被用来替换原CoLM模式中相应值及参数化方案。CoLM模式基本上能较好地模拟净辐射R_n、感热通量H、地表土壤热通量G₀和地表温度T_g日变化特征,只是在日峰值及其峰值出现时间的模拟上不理想;而CoLM模式对该地区土壤湿度M的模拟效果非常不好。误差统计值Bias、SEE、NSEE表明优化参数后的CoLM模式使得R_n的模拟误差被降低4.21%（SEE）,H的模拟误差被降低25.19%（Bias）,T_g的模拟误差被降低33.33%（Bias）、10.45%（SEE）和25%（NSEE）。  相似文献   

车贝雪夫多项式的约简算法     

黄永玉  朱应珍 《气象与环境科学》1999,(4)

解释了文献「１」中关于化整后的车贝雪夫多项式约简处理的技术原理,给出了一种可快速实现多项式约简处理的求算方法。  相似文献   

青藏高原北部地区强震演化过程研究   总被引：5，自引：0，他引：5  

杨立明  王振亚  兰丛欣 《地震》1999,19(4):372-378

研究了青藏高原北部地区≥ 7级地震时空分布特征、孕育演化过程,并探讨了物理解释。结果表明,本地区≥ 7级地震空间上受区内主要活动断裂控制,发震间隔时间具有一定的规律性;同时,本地区≥ 7级地震的孕震演化过程具有共性行为,表现为孕震构造10年尺度的大范围中强震平静,研究区2～ 5年尺度的中强震频发,末次中强震的时空任意性等特征,对区域地震分析预报具有实用价值。  相似文献   

四个鲤鱼种群ITS-1序列的遗传变异分析   总被引：1，自引：1，他引：0  

钟立强  张成锋  周凯  李冰  王建新  朱健 《湖泊科学》2011,23(2):271-276

对我国四个鲤鱼种群的核糖体DNA内转录间隔区ITS-1进行了PCR扩增、测序.序列分析显示,370bp的ITS-1序列中GC含量明显高于AT含量,共检测到34个变异位点,96个样本得到14个单倍型,平均单倍型多样性为0.637±0.055,核苷酸多样性为0.00857±0.00200,遗传多样性表现较低.黑龙江野鲤种群...  相似文献