The index of ideality of correlation: improvement of models for toxicity to algae

Toxicity to algae is important characteristic of substances from ecologic point of view. The CORAL software (http://www.insilico.eu/coral) gives possibility to build up model of toxicity to algae using data on the molecular architecture and experimental toxicity, without additional data on physicochemical and/or biochemical parameters. Considerable improvement of the model is observed in the case of using the index of ideality of correlation (IIC) in the role of additional criterion of predictive potential. The IIC is calculated with using of the correlation coefficient between experimental and calculated values of endpoint for the calibration set, with taking into account the positive and negative dispersions between experimental and calculated values. The best model calculated with use the IIC is characterized (the validation set) by n?=?50, r²?=?0.947, RMSE?=?0.401 whereas, model calculated without use the IIC is characterized by n?=?50, r²?=?0.805, and RMSE?=?0.539. The suggested models are built up in accordance to five OECD principles.

     

GROMACS: fast, flexible, and free

This article describes the software suite GROMACS (Groningen MAchine for Chemical Simulation) that was developed at the University of Groningen, The Netherlands, in the early 1990s. The software, written in ANSI C, originates from a parallel hardware project, and is well suited for parallelization on processor clusters. By careful optimization of neighbor searching and of inner loop performance, GROMACS is a very fast program for molecular dynamics simulation. It does not have a force field of its own, but is compatible with GROMOS, OPLS, AMBER, and ENCAD force fields. In addition, it can handle polarizable shell models and flexible constraints. The program is versatile, as force routines can be added by the user, tabulated functions can be specified, and analyses can be easily customized. Nonequilibrium dynamics and free energy determinations are incorporated. Interfaces with popular quantum-chemical packages (MOPAC, GAMES-UK, GAUSSIAN) are provided to perform mixed MM/QM simulations. The package includes about 100 utility and analysis programs. GROMACS is in the public domain and distributed (with source code and documentation) under the GNU General Public License. It is maintained by a group of developers from the Universities of Groningen, Uppsala, and Stockholm, and the Max Planck Institute for Polymer Research in Mainz. Its Web site is http://www.gromacs.org.     

大功率LD封装技术的研究

提出一种新的LD列阵封装方法。把热沉形状改为台阶式，使稳态工作条件下的芯片前腔面散热速度提高，前后腔面温差大幅度降低，因此可以提高COD阈值，降低腔面退化率，且更方便于光纤耦合封装。利用Ansys软件对大功率LD稳态工作的温度分布进行模拟。结果发现：改进前的芯片前、后腔面温差为9．0K，改进后温差降为3．5K，降低了60%；热沉前、后端面的温差由原来的18．2K降为8．0K，降低了56％。     

数字电视多频道延时直播系统的设计和实现

基于DVB标准设计直播系统,通过视频服务器方式进行延时直播,通过软件方法从多节目复用流中提取出多个单独的节目传输流,从而支持多个频道同时进行直播.可与硬盘播出系统进行系统集成.初步实现系统基本功能,按照相关标准进行传输流的技术指标检测,并对测试结果进行分析.     

特定领域软件框架的提取方法研究

通过分析传统业务流程、建立简单应用框架并从简单框架泛化为领域通用软件框架,采用诸如识别核心业务流程和周边业务流程、简化和规范化传统业务流程以及对功能单一的应用框架进行领域扩展等方法,从设计简单而有效的软件框架入手,通过具体的应用提取并扩展为该领域更为通用的软件框架.     

通用基础软件等级保护测评原型的研究

随着我国软件事业的迅速发展，软件安全问题也逐渐增多，给人们的正常生活、生产和工作带来了不同程度的危害和损失。当前软件安全问题已经成为了社会和人们关注的焦点问题，要提高软件的安全级别，还需要建立一套科学、系统的软件安全评估标准。虽然当前在基础软件服务上已经出台了一套行业标准，但是这些标准的统一性和可操作性还不够高，仍然存在很多不足之处，因此还需要探索新的安全测试标准体系，以用于指导国产通用基础软件的安全测试工作。     

Importance of verifying queue model assumptions before planning with simulation software

This case study uses empirical data gathered at an Australian refinery to verify the assumptions for queue distributions before using special-purpose software to plan the off-road-truck hauling of titanium dioxide to a refinery (n = 773). Easy-to-use spreadsheet software is utilized to verify assumptions for queue models. Managers are able to make decisions based on economic implications of queue models to avoid making costly planning mistakes. Analysts can use nonparametric hypothesis-testing techniques to verify distribution assumptions for optimization without having to write hard-to-maintain and complex algebraic linear equations or nonlinear search routines.     

Research on HTML5 application cache poison attack

HTML5 application cache (AppCache) allowed Web browser to access Web offline.But it also brought a new method of cache poisoning attack that was more persisting.As for websites which used the AppCache,a novel poisoning method RFTM (replace file twice method),in which the attacker replaced the manifest file twice to poison the client’s AppCache,was proposed.Compared with the original attack,the legal server would not receive abnormal HTTP requests from the client in the attack.Therefore,changing the server configuration could not prevent the client from the RFTM AppCache poisoning.To avoid the attack mentioned above,a lightweight signature defense scheme Sec-Cache in application layer was designed.Furthermore,experiments show that it has good performance and compatibility.     

‘New mathematics’ and teaching

Inside the scientific world it is not always understood that the mood of mathematics, which is a product and a part of culture, can change with time. This is partly why many have been surprised by the coming of the so‐called new mathematics.

In the truly creative mathematical mind two opposite tendencies coexist: the logical and the imaginative. Apparently it seems that new mathematics can be reduced to a purely logical machinery. In fact it contains as much imaginative contributions as classical mathematics. But it is difficult to show simultaneously the logical sequence of propositions and the clumsy progression of research itself. Mathematical exposition does not always follow the ‘ most natural slopes’ of the mind. Unfamiliar presentations often give an impression of ‘ abstraction ‘, more familiar ones an impression of concreteness ‘.

So it appears that difficulties with new mathematics are mostly of psychological origin. Misuses of it can easily raise up intolerance reactions and emotional blocks. Perhaps insisting upon the fact that, here as elsewhere, it is important to be able to guess, to realize that intuition and imagination are essential, could help to make new mathematics better understood, more useful and more able to be considered as a unifing element among sciences.