Desynchronization attack on RAPP ultralightweight authentication protocol

RAPP (RFID Authentication Protocol with Permutation) is a recently proposed and efficient ultralightweight authentication protocol. Although it maintains the structure of the other existing ultralightweight protocols, the operation used in it is totally different due to the use of new introduced data dependent permutations and avoidance of modular arithmetic operations and biased logical operations such as AND and OR.The designers of RAPP claimed that this protocol resists against desynchronization attacks since the last messages of the protocol is sent by the reader and not by the tag. This letter challenges this assumption and shows that RAPP is vulnerable against desynchronization attack. This attack has a reasonable probability of success and is effective whether Hamming weight-based or modular-based rotations are used by the protocol.     

利用ASP和关系数据库实现网络MIS系统

随着Internet技术的日益普及，利用网络实现业务管理成为一种趋势，ASP技术应运而生。ASP是微软为ⅡS和Web服务器提供的一种服务器端的开发语言脚本环境，是一种新型开放的、免编译的应用开发环境，为企业提供了一个服务开发和信息管理的解决方案。本文研究了ASP的工作模式和利用ASP访问关系数据库的关键技术，并在此基础上讨论了一个利用ASP和关系数据库实现网络MIS系统的成功实例。     

关系演算运行机制的分析与研究

在分析关系演算运行机制的同时，介绍了一种易于正确理解和设计关系演算表达式的方法，并通过实例揭示了它与SQL语言之间的密切联系。     

Ensembles of relational classifiers

Relational classification aims at including relations among entities into the classification process, for example taking relations among documents such as common authors or citations into account. However, considering more than one relation can further improve classification accuracy. Here we introduce a new approach to make use of several relations as well as both, relations and local attributes for classification using ensemble methods. To accomplish this, we present a generic relational ensemble model that can use different relational and local classifiers as components. Furthermore, we discuss solutions for several problems concerning relational data such as heterogeneity, sparsity, and multiple relations. Especially the sparsity problem will be discussed in more detail. We introduce a new method called PRNMultiHop that tries to handle this problem. Furthermore we categorize relational methods in a systematic way. Finally, we provide empirical evidence, that our relational ensemble methods outperform existing relational classification methods, even rather complex models such as relational probability trees (RPTs), relational dependency networks (RDNs) and relational Bayesian classifiers (RBCs).     

On the completeness of the Lambek Calculus with respect to relativized Relational Semantics

Recently M. Szabolcs [12] has shown that many substructural logics including Lambek CalculusL are complete with respect to relativized Relational Semantics. The current paper proves that it is sufficient forL to consider a relativization to the relation x dividesy in some fixed semigroupG.Research partially supported by the Russian Fund for Fundamental Research Grant 93-012-590.     

基于O-D的XML编码及对信息查询与更新的支持

提出了一种基于区间表示的XML编码方式，设计了相应的关系存储模式，研究了该编码方式对信息查询和信息更新的支持。鉴于XML关系存储下信息更新的困难性，采用基于order-descendan(O-D)的XML编码方式，不仅可以完全支持XPath查询语言的13个查询轴的查询功能，而且通过简单的计算即可有效地支持XML数据的增加和删除，这种简单计算可以在关系存储模式下通过SQL语句方便地实现。     

A relational framework for join implementation in model management systems

Two important issues in the design of relational model banks are the degree to which they should be aggregated or disaggregated and the methods by which disaggregated model banks might be integrated in response to user queries. Three topics relevant to this issue are addressed in this paper. The first is whether a universal model and its projections may possess the lossy join property. We will show that they do not. The second is the development of a relational algebra for the specification of join implementation in model banks, and the third is the realization of such an algebra in a language similar to Query-by-Example.     

Relational IBL in classical music

It is well known that many hard tasks considered in machine learning and data mining can be solved in a rather simple and robust way with an instance- and distance-based approach. In this work we present another difficult task: learning, from large numbers of complex performances by concert pianists, to play music expressively. We model the problem as a multi-level decomposition and prediction task. We show that this is a fundamentally relational learning problem and propose a new similarity measure for structured objects, which is built into a relational instance-based learning algorithm named DISTALL. Experiments with data derived from a substantial number of Mozart piano sonata recordings by a skilled concert pianist demonstrate that the approach is viable. We show that the instance-based learner operating on structured, relational data outperforms a propositional k-NN algorithm. In qualitative terms, some of the piano performances produced by DISTALL after learning from the human artist are of substantial musical quality; one even won a prize in an international ‘computer music performance’ contest. The experiments thus provide evidence of the capabilities of ILP in a highly complex domain such as music. Editors: Tamás Horváth and Akihiro Yamamoto     

DATALOG与关系代数

本文旨在通过描述DATALOG和关系代数的概念，以及DATALOG与关系代数的区别，经过从关系代数到逻辑规则和从逻辑到关系的论述，并比较DATALOG和关系代数，说明DATALOG是一种基于逻辑的数据模型，是PROLOG语言的数据库版本，关系代数是过程化的语言，关系代数表达式与安全、非递归、带有非操作的DATALOG程序的表达能力是相同的。     

结构化置标语言及其在数据库系统中的应用

本文讨论了将结构化置标语言应用于数据库系统之中。     

Using FP as a query language for relational data-bases

FP is the programming language defined by J. Backus to demonstrate the virtues of functional programming as opposed to conventional programming in Von Neumann-like languages.In this paper we investigate the use of FP in the framework of relational data bases. In particular, we show how the language can be used to define base relations, to derive views from a collection of relations, and to express complex database queries.The language provides all capabilities of pure algebraic relational languages, but is considerably more powerful. As such, it can be used as a formal specification language to describe the semantics of queries expressed in relational languages, such as Query-By-Example. In addition the algebra of FP programs allows one to formally prove properties of such queries.     

类关系代数的OODB理论—关联代数的分析

ＯＯＤＢ是数据库研究的新领域。文中介绍了用于面向对象数据库查询语言原型的ＯＯＤＢ理论－与关系代数相似的关联代数。通过与关系代数的比较，分析其特点，说明其优越性。最后给出基于关联的查询形式。     

A query language for retrieving information from a soil data bank

The paper presents specifications and implementation details of a query language designed for retrieving information from a soil data bank. The commands of the language are based on operations of relational algebra, and can be employed without previous programming experience. The language is part of the ARSIS (A Relational Soil Information System) system that is being developed in Greece.     

Modulo Constraints and the Complexity of Typechecking XML Views

The typechecking problem for transformations of relational data into tree data is the following: given a relational-to-XML transformation P, and an XML type d, decide whether for every database instance the result of the transformation P on satisfies d. TreeQL programs with projection-free conjunctive queries (see Alon et al. in ACM Trans. Comput. Log. 4(3):315–354, 2003) are considered as transformations and DTDs with arbitrary regular expressions as XML types. A non-elementary upper bound for the typechecking problem was already given by Alon et al. (ACM Trans. Comput. Log. 4(3):315–354, 2003) (although in a more general setting, where equality and negation in projection-free conjunctive queries and additional universal integrity constraints are allowed). In this paper we show that the typechecking problem is coNEXPTIME-complete. As an intermediate step we consider the following problem, which can be formulated independently of XML notions. Given a set of triples of the form (φ,k,j), where φ is a projection-free conjunctive query and k,j are natural numbers, decide whether there exists a database such that, for each triple (φ,k,j) in the set, there exists a natural number α, such that there are exactly k+j*α tuples satisfying the query φ in . Our main technical contribution consists of a NEXPTIME algorithm for the last problem. Partially supported by Polish Ministry of Science and Higher Education research project N206 022 31/3660, 2006/2009. This paper is an extended version of 20, where the coNEXPTIME upper bound was shown.     

一个紧耦合的CPD系统的实现

本文介绍一个在微机上实现的紧耦合ＣＰＤ系统ＰＲＯＬＥＢ及其实现技术。     

基于关系数据库的XQuery查询的实现

XML的应用日益广泛，XML数据库技术也得到迅速的发展，但是从安全性、索引结构、事务处理等方面考虑，关系数据库仍然是更加可靠的选择。本文提出了在关系数据库的基础上提供虚拟的XML数据库、并实现xQuery查询的一种中间件的设计，结合了两者的优点。     

Database Query Processing Using Finite Cursor Machines

We introduce a new abstract model of database query processing, finite cursor machines, that incorporates certain data streaming aspects. The model describes quite faithfully what happens in so-called “one-pass” and “two-pass query processing”. Technically, the model is described in the framework of abstract state machines. Our main results are upper and lower bounds for processing relational algebra queries in this model, specifically, queries of the semijoin fragment of the relational algebra.