Towards a new approach to secure database design

The problem of designing and managing a secure database system is considered in this paper. The approach which is proposed is primarily concerned with the security information definition and management in a database environment. A multiphase design methodology is presented reflecting current proposals of database design methodology. In particular four design phases are proposed: requirements analysis of the security system, conceptual, logical and physical design of security information. The content and the solution techniques of each phase are examined. A database management system architecture is also presented which is suitable to control access rights to the database.     

The measurement of a design structural and functional complexity

When evaluation of terms such as “design complexity” and its “quality”, it is often performed in an ad hoc manner. This paper attempts to remedy this situation by articulating two definitions of design complexity (structural complexity versus functional complexity), their associated value measures, and the relationships between them. The structural definition states that a design complexity is a function of its representation. Defining design complexity in the structural way provides quantitative techniques for evaluating vague terms. The functional definition states that a design complexity is a function of its probability of successfully achieving the required specifications (functional requirements and constraints). The proposed measurable metrics provide a proper basis for evaluating each step of the design process, and accordingly recommends the direction to follow for design modification and enhancement. It also provides a framework for comparing competing artifacts     

CARRADS: Cross layer based adaptive real-time routing attack detection system for MANETS

Routing behavior in ad hoc networks is highly transient. Thus, dynamically adapting the routing attack detection system at real-time to new attacks and changing network conditions is critical in ad hoc networks. Conventional incremental learning methods are computationally expensive for resource-constrained nodes in ad hoc networks. In this paper, we propose CARRADS, a computationally efficient methodology for adapting the intrusion detection model at real-time. The adaptation process consists of two major stages. In the first stage, the main task is to identify occurrence of new patterns in the routing control traffic and prioritize them based on their information content. The second stage of adaptation is to incrementally update the detection model using the new patterns with minimum computational overhead. CARRADS uses SVM algorithm for its superior detection abilities. However, using some innovative techniques the computational overhead of incremental update is reduced by a factor of 20 to 30 times at the cost of a negligible decrease in detection accuracy. This makes CARRADS a viable approach for real-time IDS in ad hoc networks.     

基于元建模的移动Ad Hoc网络性能优化

针对移动Ad Hoc网络性能优化过程中的仿真模型精确性与仿真模型运行效率之间的矛盾,提出了利用相关向量元模型来拟合网络仿真模型并进行优化的解决方法.重点研究了元建模方法中的实验设计方法、元模型拟合方法、模型验证与评估等关键技术.利用适度精确的元模型替代仿真模型进行设计空间探索和多目标优化,实验结果表明,基于元模型的优化可以成功应用于移动Ad Hoc网络等复杂系统建模、分析与优化,有效提高此类计算密集过程的计算效率.     

Information system analysis and conceptual database design in production environments with M1

A methodology, called M¹, for information system analysis and database design of production environments is presented in detail. The originality of M¹ is to recognize the importance of integrating factory analysis methods for data and user requirements definition with logical database design methods for database specification. M¹ is a pragmatic, complete, manual methodology involving three major phases: Enterprise Modelling and Analysis which is the phase devoted to accurate analysis of the structure of the enterprise and precise definition of the scope of the future database application; Conceptual Design which is the phase concerned with data modelling of both static and dynamic properties of the enterprise; and Implementation Design which is the phase dealing with adaptation of the conceptual schema to the data model specifications of the physical database system used for application development and tuning performances of the physical system. The methodology is explained and illustrated by means of an example related to a Flexible Manufacturing System for mechanical parts.     

Business process analysis in healthcare environments: A methodology based on process mining

Performing business process analysis in healthcare organizations is particularly difficult due to the highly dynamic, complex, ad hoc, and multi-disciplinary nature of healthcare processes. Process mining is a promising approach to obtain a better understanding about those processes by analyzing event data recorded in healthcare information systems. However, not all process mining techniques perform well in capturing the complex and ad hoc nature of clinical workflows. In this work we introduce a methodology for the application of process mining techniques that leads to the identification of regular behavior, process variants, and exceptional medical cases. The approach is demonstrated in a case study conducted at a hospital emergency service. For this purpose, we implemented the methodology in a tool that integrates the main stages of process analysis. The tool is specific to the case study, but the same methodology can be used in other healthcare environments.     

Designing secure databases

Security is an important issue that must be considered as a fundamental requirement in information systems development, and particularly in database design. Therefore security, as a further quality property of software, must be tackled at all stages of the development. The most extended secure database model is the multilevel model, which permits the classification of information according to its confidentiality, and considers mandatory access control. Nevertheless, the problem is that no database design methodologies that consider security (and therefore secure database models) across the entire life cycle, particularly at the earliest stages currently exist. Therefore it is not possible to design secure databases appropriately. Our aim is to solve this problem by proposing a methodology for the design of secure databases. In addition to this methodology, we have defined some models that allow us to include security information in the database model, and a constraint language to define security constraints. As a result, we can specify a fine-grained classification of the information, defining with a high degree of accuracy which properties each user has to own in order to be able to access each piece of information. The methodology consists of four stages: requirements gathering; database analysis; multilevel relational logical design; and specific logical design. The first three stages define activities to analyze and design a secure database, thus producing a general secure database model. The last stage is made up of activities that adapt the general secure data model to one of the most popular secure database management systems: Oracle9i Label Security. This methodology has been used in a genuine case by the Data Processing Center of Provincial Government. In order to support the methodology, we have implemented an extension of Rational Rose, including and managing security information and constraints in the first stages of the methodology.     

NoC synthesis flow for customized domain specific multiprocessor systems-on-chip

The growing complexity of customizable single-chip multiprocessors is requiring communication resources that can only be provided by a highly-scalable communication infrastructure. This trend is exemplified by the growing number of network-on-chip (NoC) architectures that have been proposed recently for system-on-chip (SoC) integration. Developing NoC-based systems tailored to a particular application domain is crucial for achieving high-performance, energy-efficient customized solutions. The effectiveness of this approach largely depends on the availability of an ad hoc design methodology that, starting from a high-level application specification, derives an optimized NoC configuration with respect to different design objectives and instantiates the selected application specific on-chip micronetwork. Automatic execution of these design steps is highly desirable to increase SoC design productivity. This work illustrates a complete synthesis flow, called Netchip, for customized NoC architectures, that partitions the development work into major steps (topology mapping, selection, and generation) and provides proper tools for their automatic execution (SUNMAP, xpipescompiler). The entire flow leverages the flexibility of a fully reusable and scalable network components library called xpipes, consisting of highly-parameterizable network building blocks (network interface, switches, switch-to-switch links) that are design-time tunable and composable to achieve arbitrary topologies and customized domain-specific NoC architectures. Several experimental case studies are presented In the work, showing the powerful design space exploration capabilities of the proposed methodology and tools.     

Progressive design methodology for complex engineering systems based on multiobjective genetic algorithms and linguistic decision making

This work focuses on a design methodology that aids in design and development of complex engineering systems. This design methodology consists of simulation, optimization and decision making. Within this work a framework is presented in which modelling, multi-objective optimization and multi criteria decision making techniques are used to design an engineering system. Due to the complexity of the designed system a three-step design process is suggested. In the first step multi-objective optimization using genetic algorithm is used. In the second step a multi attribute decision making process based on linguistic variables is suggested in order to facilitate the designer to express the preferences. In the last step the fine tuning of selected few variants are performed. This methodology is named as progressive design methodology. The method is applied as a case study to design a permanent magnet brushless DC motor drive and the results are compared with experimental values.     

Automatic multi-objective clustering based on game theory

Data clustering is a very well studied problem in machine learning, data mining, and related disciplines. Most of the existing clustering methods have focused on optimizing a single clustering objective. Often, several recent disciplines such as robot team deployment, ad hoc networks, multi-agent systems, facility location, etc., need to consider multiple criteria, often conflicting, during clustering. Motivated by this, in this paper, we propose a sequential game theoretic approach for multi-objective clustering, called ClusSMOG-II. It is specially designed to optimize simultaneously intrinsically conflicting objectives, which are inter-cluster/intra-cluster inertia and connectivity. This technique has an advantage of keeping the number of clusters dynamic. The approach consists of three main steps. The first step sets initial clusters with their representatives, whereas the second step calculates the correct number of clusters by resolving a sequence of multi-objective multi-act sequential two-player games for conflict-clusters. Finally, the third step constructs homogenous clusters by resolving sequential two-player game between each cluster representative and the representative of its nearest neighbor. For each game, we define payoff functions that correspond to the model objectives. We use a methodology based on backward induction to calculate a pure Nash equilibrium for each game. Experimental results confirm the effectiveness of the proposed approach over state-of-the-art clustering algorithms.     

Further Analysis of the Entity-Relationship Approach to Database Design

The nondeterministic or deterministic entity-relationship model of a database is formaRy defined as a user's view of that database in terms of a collection of time-varying relations: the regular or weak entity relations, or the regular or weak relationship relations. Both nondeterministic and deterministic entity-relationship models have the same strength to characterize information concerning entities and relationships which exist in our minds. An improved table form of the relations is introduced to provide a clear and concise user's view of databases. The basic concept of the entity-relationship approach to the logical database design is provided, and is used to derive 3NF relations. FinaUly, a method of representing physicaly these relations, which are generated by the use of the entity-relationship approach to the logical database design, is presented. Thus, the entity-relationship approach to the logical and physical database design can also be realized.     

Cooperative Caching in Wireless P2P Networks: Design, Implementation, and Evaluation

Some recent studies have shown that cooperative cache can improve the system performance in wireless P2P networks such as ad hoc networks and mesh networks. However, all these studies are at a very high level, leaving many design and implementation issues unanswered. In this paper, we present our design and implementation of cooperative cache in wireless P2P networks, and propose solutions to find the best place to cache the data. We propose a novel asymmetric cooperative cache approach, where the data requests are transmitted to the cache layer on every node, but the data replies are only transmitted to the cache layer at the intermediate nodes that need to cache the data. This solution not only reduces the overhead of copying data between the user space and the kernel space, it also allows data pipelines to reduce the end-to-end delay. We also study the effects of different MAC layers, such as 802.11-based ad hoc networks and multi-interface-multichannel-based mesh networks, on the performance of cooperative cache. Our results show that the asymmetric approach outperforms the symmetric approach in traditional 802.11-based ad hoc networks by removing most of the processing overhead. In mesh networks, the asymmetric approach can significantly reduce the data access delay compared to the symmetric approach due to data pipelines.     

Joint routing and flow rate optimization in multi-rate ad hoc networks

Typical radios in ad hoc networks can support multi-rate transmissions. However, traditional routing protocols do not use this feature well in multi-rate ad hoc networks and therefore, the network performance and resource utilization are not optimized. Some algorithms have been proposed to take advantage of the multi-rate transmission scheme, but their performance is not optimized either. In this paper, we show that a cross-layer optimization based approach can significantly improve the performance of multi-rate ad hoc networks over existing routing algorithms. For this, we consider link interference and propose joint routing and flow rate optimization for optimal performance in multi-rate ad hoc networks, i.e., a Cross-layer Optimization based Model for Multi-rate Ad hoc Networks (COMMAN). Considering the characteristics of multi-rate ad hoc networks, we design and implement a distributed heuristic of this centralized model. It is shown that the distributed heuristic algorithm can approximate the performance of COMMAN closely.     

Software Development

Software development has emerged as a critical bottleneck in the human use of automatic data processing. Beginning with ad hoc heuristic methods of design and implementation of software systems, problems of software maintenance and changes have become unexpectedly large. It is contended that improvement is possible only with more rigor in software design and development methodology. Rigorous software design should survive its implementation and be the basis for further evolution. Software development should be done incrementally, in stages with continuous user participation and replanning, and with design-to-cost programming within each stage.     

Storing XML (with XSD) in SQL databases: interplay of logical and physical designs

Much of business XML data has accompanying XSD specifications. In many scenarios "shredding" such XML data into a relational storage is a popular paradigm. Optimizing evaluation of XPath queries overmuch XML data requires paying careful attention to both the logical and physical designs of the relational database where XML data is shredded. None of the existing solutions has taken into account physical design of the generated relational database. In this paper, we study the interplay of logical and physical design and conclude that 1) solving them independently leads to suboptimal performance and 2) there is substantial overlap between logical and physical designs: some well-known logical design transformations generate the same mappings as physical design. Furthermore, existing search algorithms are inefficient to search the extremely large space of logical and physical design combinations. We propose a search algorithm that carefully avoids searching duplicated mappings and utilizes the workload information to further prune the search space. Experimental results confirm the effectiveness of our approach.     

Handling complex and uncertain information in the ExIFO andNF2 data models

Trends in databases leading to complex objects present opportunities for representing imprecision and uncertainty that were difficult to integrate cohesively in simpler database models. In fact, one can begin at the conceptual level with a model that allows uncertainty assumptions and then transform those assumptions into a logical model having the necessary semantic foundations upon which to base a meaningful query language. Here we provide such a constructive approach beginning with the ExIFO model for expression of the conceptual design then show how the conceptual design is transformed into the logical design (for which we utilize the extended NF² logical database model). The steps are straightforward, unambiguous, and preserve the relevant information, including information concerning uncertainty     

Database design practices for inverted files

Database research literature has proposed many procedures, both manual and automated, for database design; selection of secondary indexes for inverted file type database management systems (DBMS) has been repeatedly addressed. The empirical study reported here indicates that practical inverted file design has been relatively unaffected by this research.This paper characterizes the actual database design process used at inverted file DBMS installations along such dimension as: types of secondary keys constructed, the individuals who make index design decisions, the decisions that are changed (and when) after the initial database implementation, the factors that are considered in indexing decisions, and the literature which is used in the process. The study shows that key selection (as one example of a design decision) is addressed by ad hoc procedures and well conceived procedures are not used. Further, the results indicate that database design is dominated by users and systems analysts, indexes are frequently changed and a wide range of database performance and convenience factors are influential in practice. The paper concludes with some recommendations for database design support tools.     

The design and implementation of an intelligent query tool for relational databases

Abstract: Retrieving ad hoc data from information systems is difficult for non-expert users. Despite the efforts made in improving query tools (e.g. visual query construction, Query By Example, query templates), empirical research shows that constructing a request is still difficult (Reisner 1988). The core of the problem seems to be in the difference between the way the user perceives the application domain and the way the system requires the user to see it (Carroll & Olsen 1988).
In this paper we describe the design and implementation of an ad hoc query tool developed by RCC for a personnel information system, and how AI techniques contributed to this module. The main novel idea incorporated in the query tool is to present the user with a means to question the conceptual model of the system instead of the technical model. To support this, a blackboard architecture has been designed and implemented with knowledge sources that translate the user's questions to database queries. The query tool is used in daily practice by over 100 users.     

一种面向无线Ad Hoc网络的新型分布式哈希表

为了在无线ad hoc网络上构建各种应用系统,有必要提供一种高效的数据共享机制,使得网络中各节点之间能够方便地进行协同和交互。该文将分布式哈希表(DHT)的基本思想与无线ad hoc网络中的基于地理位置的路由技术结合起来,提出了一种新型的面向无线ad hoc网络的数据共享方案——基于位置的DHT(LDHT)。与传统的DHT方案相比,LDHT不是通过逻辑上的覆盖网络来实现,而是直接基于网络的物理拓扑结构来构建,有效地消除了传统DHT方案的拓扑结构不匹配问题,提高了在无线ad hoc网络中进行数据共享的效率。     

Service discovery in mobile ad hoc networks: A field theoretic approach

Service discovery in mobile ad hoc networks is challenging because of the absence of any central intelligence in the network. Traditional solutions as used in the Internet are hence not well suited for mobile ad hoc networks. In this paper, we present a novel decentralized service discovery mechanism for ad hoc networks. The basic idea is to distribute information about available services to the network neighborhood. We achieve this by using the analogy of an electrostatic field: A service is modelled by a (positive) point charge, and service request packets are seen as (negative) test charges which are attracted by the service instances. In our approach, we map the physical model to a mobile ad hoc network in a way where each network element calculates a potential value and routes service requests towards the neighbor with the highest potential, hence towards a service instance. Our approach allows for differentiation of service instances based on their capacity. We define the required protocols and methods which we implemented in a network simulator. Using extensive simulations, we evaluate the performance and robustness of the mechanisms. The results indicate good performance and convergence even in highly mobile environments. We believe that this technique can and should be further exploited, e.g., as a routing protocol in mobile ad hoc networks.