Observation on some of the environmental parameters and feed quality of selected golda (Macrobrachium rosenbergii) farms in Bangladesh

A study was conducted to ascertain the existing farm water, effluent and feed quality of selected giant freshwater prawn farms from major prawn farming areas (Bagerhat Sadar, Noakhali Sadar and Mymensingh) of Bangladesh during July to November 2005. Water quality parameters such as the mean values of dissolved oxygen, alkalinity, nitrite-nitrogen, phosphate-phosphorus and ammoniacal nitrogen did not show any significantly differences among the farming areas. Whereas significant differences (p < 0.05) were observed in the mean values of temperature, secchi disc visibility, pH and chlorophyll a. However, all the water quality parameters in the farming areas were within the suitable range for prawn culture. There was no significant variation in nutrients concentration of discharged effluent among the prawn farming areas. All of the nutrients measured in effluent water were within the acceptable range and did not seem to pose a direct threat to the recipient environment. The analysed crude protein contents of commercial CP, Quality and Saudi-Bangla prawn feeds were 31.84%, 27.21% and 28.97%, respectively, whereas all analysed farm made feeds were less than 25%. The other nutrients of prawn feeds varied largely with the source of feeds and ingredients used to prepare feed. The annual yield of prawn varied from 320.4 to 512.6 kg/ha (mean 412.3 kg/ha) depending on the management system.

Beel fishery and livelihood of the local community in Rajdhala, Netrakona, Bangladesh

Baseline survey and Participatory Rural Appraisal (PRA) during January 2003 to December 2004 on the fishing community revealed that unregulated fishing, use of destructive fishing gears, poaching of fishes, difficulties encountered in enforcing fisheries regulation and the helplessness of fishers to find alternative sources of income during banned fishing period (June to October) were the major management problems. CBFM (Community Based Fisheries Management) system as an alternative management strategy has been introduced to ensure active participation of the target group-the poor fishers living around the beet who were previously deprived to get access to the beet. Establishing a leasing system for controlled access, ensuring greater user-group participation through equitable distribution of all resource benefits among members, attempting to enforce penalties for illegal fishing linked with surprise checks to enforce management regulations are some of the recent steps taken by the BMC (Beel Management Committee). Chapila fish intake by the community was 31.25 g/head/day before stocking the beel by carp fingerlings. After stocking, they consumed chapila as fish protein from 8.33 g to 20.8 g/head/day during the fishing season (November to May) indicating that due to introduction of carp fingerlings, chapila production has been decreased in 2003-2004. About 77.5% families around the beel were found to be dependent directly and/or indirectly on chapila and other indigenous fishes of the beel for their livelihood, through fishing, marketing and other activities like net and boat preparation and nets mending etc. Particularly fishers' families were found to face serious problem during non-fishing period like June to October for their livelihood. Analyzing the present research result it was also observed that other than declination in biodiversity, the fishing pressure on promising chapila of the beel was found high and that is why the production of chapila has also been decreased. To get sustainable chapila production from the heel, it is suggested to ensure successful spawning and recruitment as juveniles, and hence the chapila should be undisturbed during its breeding period from March to July, and fishing pressure on the same species needs to be reduced for obtaining sustainable fish production.

Survival, growth and production of Penaeus monodon and P. indicus at different density combinations with milkfish

Penaeus monodon and P. indicus juveniles were stocked and reared for about 3 months in earthen ponds at different density combinations with Chanos chanos. The presence of either Penaeus species at any density ratio did not affect significantly the C. chanos survival. Survival rates of the penaeids indicated that intraspecific and interspecific competition occurred and were reduced with the reduction in stocking rate. It is concluded that further studies on higher density ratios and feeding and economic consideration would be of help to the development of this kind of fishpond management system.

Development of teaching resources for physical modelling community

Physical modelling of interesting geotechnical problems has helped clarify behaviours and failure mechanisms of many civil engineering systems. Interesting visual information from physical modelling can also be used in teaching to foster interest in geotechnical engineering and recruit young researchers to our field. With this intention, the Teaching Committee of TC2 developed a web-based teaching resources centre. In this paper, the development and organisation of the resource centre using Wordpress. Wordpress is an open-source content management system which allows user content to be edited and site administration to be controlled remotely via a built-in interface. Example data from a centrifuge test on shallow foundations which could be used for undergraduate or graduate level courses is presented and its use illustrated. A discussion on the development of wiki-style addition to the resource centre for commonly used physical model terms is also presented. © 2010 Taylor & Francis Group, London.

Fertile-free annular fuel for plutonium recycling

Up to 50% increase in the power density of the existing pressurized water reactor (PWR)-type reactors can be achieved by the use of internally and externally cooled annular fuel geometry. As a result, the accumulated stock-piles of Pu, especially if incorporated infertile-free inert matrix, can be burnt at a substantially higher rate as compared with the conventional mixed oxide-fueled reactors operating at standard power density. In this work, we explore the basic feasibility of a PWR core fully loaded with Pu incorporated infertile-free fuel of annular internally and externally cooled geometry and operating at 150% of nominal power density. We evaluate basic burnable poison designs, fuel management strategies, and reactivity feedback coefficients. The three-dimensional full core neutronic analysis performed with Studsvik Core Management System showed that the design of such a Pu-loaded annular fuel core is feasible but significantly more challenging than the Pu fertile-free core with solid fuel pins operating at nominal power density. The main difficulty arises from the fact that the annular fuel core requires at least 50% higher initial Pu loading in order to maintain the standard fuel cycle length of 18 months. Such a high Pu loading results in hardening of the neutron spectrum and consequent reduction in reactivity worth of all reactivity control mechanisms and, in some cases, positive moderator temperature coefficient (MTC). The use of isotopically enriched Gd and Er burnable poisons was found to be beneficial with respect to maximizing Pu burnup and reducing power peaking factors. Overall, the annular fertile-free Pu-loaded high-power-density core appears to be feasible, although it still has relatively high power peaking and potential for slightly positive MTC at beginning of cycle. However, we estimate that limiting the power density to 140% of the nominal case would assure acceptable core power peaking and negative MTC at all times during the cycle.

基于MDA的TRISO-Model模型管理方法及应用

TRISO-Model(tridimensional integrated software development model)是为处理软件开发的复杂性和动态性而提出的三维集成软件开发方法学,其中,多维模型之间的语义一致性维护以及对模型应用中公共操作部分的重用,提出了基于一致语义进行模型管理的需求.给出了基于MDA(model driven architecture)进行模型管理的方法MDA-MMMethod(MDA based model management method),应用MDA的4层模型管理结构,基于MDA核心标准MOF(meta object facility)所提供的公共语义基础管理模型和元模型,MDA-MMMethod支持各种MDA模型操作标准实现在TRSIO-model应用中的重用.开发了相应的支持系统MDA-MMSystem(MDA based model management system),应用于SoftPM的项目实践中.与传统方法相比,模型应用的开发效率得到了显著提高,同时降低了开发成本.最后,给出了模型融合的应用实例介绍.

一种Web应用服务器集群管理系统的设计与实现

随着计算机的普及和网络技术的发展，Internet上的Web用户爆炸性增长。作为Web应用主要支撑平台的Web应用服务器经常面临过载的问题。Web应用服务器集群技术是解决这一问题的有效手段。然而，集群规模变大导致的集群拓扑结构复杂、计算环境的高度异构以及应用对性能等非功能需求的多样化使得Web应用服务器集群的安装、配置和维护等管理过程难度大大增加。Web应用服务器集群迫切需要改变目前静态、被动的管理方式，而通过自管理方式来降低其管理成本、适应计算环境变化以及应用的个性化非功能需求。 Web应用服务器集群管理主要包括拓扑结构、资源以及负载等方面的管理。本文设计了一个Web应用服务器集群管理系统。针对集群拓扑结构管理，设计了基于广播的集群节点自配置设施，并通过基于Cookie Insertion的请求会话粘滞设计实现了多个负载均衡器的协同工作；针对集群资源管理，设计了基于Java规则引擎的动态资源管理框架，并在此基础上实现了集群规模的动态调整；针对集群负载管理，设计了基于反馈-控制机制的动态负载均衡算法，可根据节点负载动态调整权值，使集群能够适应负载变化。 基于上述设计，本论文在Web应用服务器系统OnceAS中实现了该集群管理系统，包括支持多种通信模式的集群通信组件，拓扑结构管理器，资源管理器，负载均衡器，以及节点管理器，同时提供了相应的管理工具。系统测试结果表明，该系统支持集群拓扑结构、资源和负载的管理，能够更好地适应负载变化，提高Web应用服务器的整体性能表现。

一个面向软件过程的知识挖掘与管理系统

软件过程的知识密集性特征要求组织人员的密切协作、交流,并能够有效地重用组织的实践经验。数据挖掘技术能够从大规模数据中发现有意义的知识,能够为知识管理提供有益的支持,从而得到更好的知识共享和重用效果。在对软件过程进行分析的基础上,提出了协同知识管理模型。介绍了一个集成的面向软件过程的知识挖掘与管理系统iKnow。对iKnow的知识表示、知识挖掘、知识服务和个性化知识检索进行了论述。系统使软件组织的实践经验成为可视、可控和可重用的知识资源。

基于安全操作系统的电子证据获取与存储

基于实时取证的思想,提出了一种安全可取证操作系统(security forensics operating system,简称SeFOS)的概念和实现思路.提出了其总体结构,建立了该系统的取证行为模型,对其取证服务和取证机制进行了分析并作了有关形式化描述,阐述了证据数据的采集和安全保护方法,提出把取证机制置于内核,基于进程、系统调用、内核资源分配和网络数据等获取证据的方法,并通过模拟实验验证了SeFOS的可取证性.可取证操作系统的研究对于进一步研究可取证数据库管理系统(forensic database management system,简称FDBMS)和可取证网络系统(forensic network,简称FNetWork)具有重要意义.

一种基于JMX的远程作业管理系统设计与实现

文章提出了一种新型远程作业管理系统框架.该框架基于JMX架构,融合了基于企业权限映射模型的安全机制、JSF（Java Server Face）的可视化框架等多项技术,有效地改进了传统的作业管理系统的可扩展性差、安全机制不足和缺乏统一、完善的系统管理三点不足.并基于该框架实现了国家863项目“远程作业管理系统”,实现了灵活的系统组件动态配置,基于企业权限映射模型的高安全和可视化管理界面,比较了实现系统和传统系统的优点,讨论了其中涉及到的关键技术.

一种基于JMX的可动态管理的远程作业系统

中国计算机学会

基于ISO9000和CMM的软件质量管理系统的研究

中国计算机学会