父母的行为里藏着孩子成长的“密码”

在对待孩子问题上,中国的父母是世界上最累的父母。父母费尽心血培养出的孩子却不懂感恩,反而觉得父母管束太多,自由选择空间太少——这一切并非我们想要的情形。那么,怎么样才是好的教育,做父母的应该如何爱孩子才是科学的呢?作为父母应勇敢走出误区,把孩子放下,用智慧眼光认识孩子,用智慧方式走进孩子世界,还给孩子有爱的童年,与孩子建立亲密和温暖的关系。

“密码”也害人

一只名为“密码” 的新病毒正通过Outlook 及Out-look Express 电子邮件散播,“Password”密码病毒内建SMTP Engine,企图避开客户端防毒软件侦测。即使用户不执行附件,该病毒也会在预览状况感染系统,尤其对于固接的宽带用户及企业而言,更具危险性。建议使用者关闭预览功能,而防毒软件使用者应即刻更新病毒码,以免该蠕虫大量传播占据网络带宽,从而影响区域网络运作。趋势科技呼吁企业采用网关防毒,即刻过滤含有De-crypt-password.exe附件的E-mail。“密码”病毒信件信息如下(如图):

解读小学语文教材课后习题中的“密码”

语文是一门学习语言文字应用的综合性、实践性课程,为了避免教材机械枯燥,展现语文的魅力,一直以来教师都致力于将听、说、读、写等知识点融入课后练習中,以强化学生对知识的应用。而课后习题作为教学的重要组成部分,是教师开展各项教学活动的得力助手,也助于各项教学目标的实现。

An Improved Framework of Massive Superpoly Recovery in Cube Attacks Against NFSR-Based Stream Ciphers

A critical problem in the cube attack is how to recover superpolies efficiently.As the targeting number of rounds of an iterative stream cipher increases,the scale of its superpolies becomes larger and larger.Recently,to recover massive superpolies,the nested monomial prediction technique,the algorithm based on the divide-and-conquer strategy,and stretching cube attacks were proposed,which have been used to recover a superpoly with over ten million monomials for the NFSR-based stream ciphers such as Trivium and Grain-128AEAD.Nevertheless,when these methods are used to recover superpolies,many invalid calculations are performed,which makes recovering superpolies more difficult.This study finds an interesting observation that can be used to improve the above methods.Based on the observation,a new method is proposed to avoid a part of invalid calculations during the process of recovering superpolies.Then,the new method is applied to the nested monomial prediction technique and an improved superpoly recovery framework is presented.To verify the effectiveness of the proposed scheme,the improved framework is applied to 844-and 846-round Trivium and the exact ANFs of the superpolies is obtained with over one hundred million monomials,showing the improved superpoly recovery technique is powerful.Besides,extensive experiments on other scaled-down variants of NFSR-based stream ciphers show that the proposed scheme indeed could be more efficient on the superpoly recovery against NFSR-based stream ciphers.

密码锁问题（续）——密码锁程序

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Analysis of Codon Usage Between Different Poplar Species

Codon usage is the selective and nonrandom use of synonymous codons to encode amino acids in genes for proteins. The analysis of codon usage may improve the understanding of cocion preferences between different species and allow to rebuild the codons of exogenous genes to increase the expression efficiency of exogenous genes, Here, codon DNA sequence （CDS） of four poplar species, including Populus tremuloides Michx., P. tomentosa Carr., P. deltoides Marsh., and P. trichocarpa Torr. ＆ Gray., is used to analyze the relative frequency of synonymous codon （RFSC）. High-frequency codons are selected by high-frequency （HF） codon analysis. The results indicate that the codon usage is common for all four poplar species and the codon preference is quite similar among the four poplar species. However, CCT encoding for Pro, and ACT coding for Thr are the preferred codons in P. tremuloides and P. tomentosa, whereas CCA coding for Pro, and ACA coding for Thr are preferred in P. deltoides and P. trichocarpa The codons such as TGC coding for Cys, TTC coding for Phe, and AAG coding for Lys, are preferred in the poplar species except P trichocarpa. GAG coding for Glu is preferred only in P deltoides, while the other three poplar species prefer to use GAA. The commonness of preferred codon allows exogenous gene designed by the preferred cocion of one of the different poplar species to be used in other poplar species.

The Factors Shaping Synonymous Codon Usage in the Genome of Burkholderia mallei

Burkholderia mallei is regarded as a potential biological weapon by the Centers for Disease Control and Prevention. In this study, the main factors shaping codon usage in the genome of B. mallei ATCC 23344 were firstly reported. The results showed that the primary trend in codon usage variation in the B. mallei is due to translational selection; while compositional mutation bias is relatively the weaker influence and the hydrophobicity of each protein and gene length are only the minor influences. At the same time, 21 codons defined firstly as ＇optimal codons＇ might provide more useful information for the expression of target genes and development of a vaccine to prevent glanders.

NEW REMOTE USER AUTHENTICATION SCHEME USING SMART CARD

Because the modified remote user authentication scheme proposed by Shen, Lin and Hwang is insecure, the Shen-Lin-Hwang＇ s scheme is improved and a new secure remote user authentication scheme based on the bi- linear parings is proposed. Moreover, the effectiveness of the new scheme is analyzed, and it is proved that the new scheme can prevent from all kinds of known attack. The one-way hash function is effective in the new scheme. The new scheme is proved that it has high effectiveness and fast convergence speed. Moreover, the ap- plication of the new scheme is easy and operational.

DISTRIBUTIONS OF TRIPLET CODONS IN MESSENGER RNA SECONDARY STRUCTURES

Analysis of the secondary structures of mRNAs which encode mature peptides shows that the location of each codon in mRNA secondary structure has a trend, which appears to be in agreement with the conformational property of the corresponding amino acid to some extent. Most of the codons that encode hydrophobic amino acids are located in stable stem regions of mRNA secondary structures, and vice versa, most of the codons that encode hydrophilic amino acids are located in flexible loop regions. This result supports the recent conclusion that there may be the information transfer between the three dimensional structures of mRNA and the encoded protein.

Security of Application System

A safe and reliable application system frame based on Internet and Intranet for Stock Supervision and Administration Council of China is built up. An all sided, multi tier and multi technical security method has been adopted, which includes identity recognition, data encryption, digital signature, Domino and WWW servers, access control list, directory service, certificate authorization server, IC card and so on. The recognition system based on CA server is a high efficient, convenient and reliable system. The encryption technology and security method are proved to be reliable. The recognition system is of high security and is worthy of being popularized in some places where some special security requirements need meeting. Multi tier technology can improve the security of database. Double keys method is a useful data encryption method.

Analysis of a Class of Logical Functions over Galois and Z_m Rings

In this paper, the author analyzed some cryptographic properties of a class of logical functions, f(x,y)=(q(x),...,q(x))·y+h(x),over Galois rings and residue rings, presented the relationship between the character spectrum of f(x,y) and the character speetrum of q(x),h(x) and the relationship between the cryptographic properties of f(x,y) and the cryptographic properties of h(x).

Discriminant Classification Model of DNA Sequence

[Objective] The research aimed to construct the discriminant classification model of DNA sequence by combining with the biology knowledge and the mathematical method.[Method] According to the polarity nature of side chain radical in the amino acid,the classification information of amino acid which represented the sequence characteristic from the content and array situation of base was extracted from the different sequences that the amino acid content was different.The four-dimension vector was used to represent.Mahalanobis distance and Fisher discriminant methods were used to classify the given sequence.[Result] In the model,the back substitution rates of sample obtained by two kinds of classification methods were both 100%,and the consistent rate of classification was 90%.[Conclusion] In the model,the calculation method was simple,and the accuracy of classification result was higher.It was superior to the discriminant classification model which was only based on the base content.

Site discrepancy of synonymous codon usage in SARS coronavirus and other viruses in Coronaviridae

The synonymous codon usage in the translational initiation and termination regions of genes of severe acute respiratory syndrome (SARS) coronavirus and five other viruses in Coronaviridae was systematically analyzed.The results indicate that most minor codons for these coronaviruses are preferentially used in the initial and terminal region.The minor codons preferentially used in the initial region are thought to have a negative effect on gene expression,which can be explained by the minor codon modulator hypothesis.It also indicates that the minor codons preferentially used in the terminal region may regulate the level of gene expression.The proposed results strongly imply that the minor codon modulator hypothesis can be applied to both some bacteria and some viruses.

STRONGER PROVABLE SECURE MODEL FOR KEY EXCHANGE

The key exchange is a fundamental building block in the cryptography. Several provable security models for the key exchange protocol are proposed. To determine the exact properties required by the protocols, a single unified security model is essential, The eCK , eCK and CK models are examined and the result is proved that the eCK＇ model is the strongest provable security model for the key exchange. The relative security strength among these models is analyzed. To support the implication or non-implication relations among these models, the formal proofs and the counter-examples are given.

Proxy signature scheme for ID-based original signers and certificate-based proxy signers

To realize delegation between different users in a mixed cryptosystem,a proxy signature scheme for ID-based original signers and certificated-based proxy signers（PSS-ID-CER）is defined.Using the bilinear properties of the pairings and the characters of key generations of certificate-based cryptosystems and ID-based cryptosystems,a construction for such a scheme is also presented.To prove the security of the proposed scheme,a general security model for this scheme under adaptive chosen-PKG,chosen-ID,chosen-delegation,chosen-ProxySigner-public-key,chosen-proxy-key and chosen-message attack is defined.The proposed scheme is provably secure under the random oracle model and the hardness assumption of computational Diffie-Hellman problem.

DNA Sequence Classification Based on the Side Chain Radical Polarity of Amino Acids

The features of DNA sequence fragments were extracted from the distribution density of the condons in the individual cases of DNA sequence fragments. Based on the polarity of side chain radicals of amino acids molecules, the amino acids were classified into five categories, and the frequencies of these five categories were calculated. This kind of feature extraction based on the biological meanings not only took the content of basic groups into consideration, but also considered the marshal ing sequence of the basic groups. The hierarchical clustering analysis and BP neural network were used to classify the DNA sequence fragments. The results showed that the classification results of these two kinds of algo-rithms not only had high accuracy, but also had high consistence, indicating that this kind of feature extraction was superior over the traditional feature extraction which only took the features of basic groups into consideration.

对南大《有机化学》中蛋白质合成示意图的磋商

本文对南京大学《有机化学》等书中所作的蛋白质合成示意图提出磋商其中存在的错误,以及出现错误的原因,并提出两种改正错误的方法,以供同行讨论。