基于POEM_SLPP的人脸识别算法

针对方向边缘幅值模式(Patterns of Oriented Edge Magnitudes,POEM)提取的人脸特征维数过高和计算复杂度较大的问题,提出了结合方向边缘幅值模式和有监督的局部保持投影(Patterns of Oriented Edge Magnitudes _Supervised Locality Preserving Projections,POEM_SLPP)的人脸识别算法。首先,采用POEM算子进行特征提取;其次,将高维特征数据投影到SLPP算法求出的低维样本空间进行降维;最后,采用最近邻法对测试样本进行分类。在CAS-PEAL-R1人脸库上的实验结果表明,在姿态、背景、修饰、年龄、距离测试集上,该算法的平均识别率较POEM LPP算法提高了22%,较POEM PCA提高了2%。     

一种新融合算法的维吾尔族人脸识别

针对维吾尔族人脸在光照以及部分遮挡下的辨识率下降和鲁棒性差的问题,提出了二维离散余弦变换（2DDCT）与方向边缘幅值模式（POEM）相融合的维吾尔族人脸识别算法。首先,把维吾尔族人脸图像分块处理,并使用2DDCT把其分块后的维吾尔族人脸图像转换为频域状态;其次,压缩维吾尔族人脸图像以排除维吾尔族人脸图像中无用信息,即中频部分与非低频部分,并进行二维离散余弦逆变换（IDCT）得到重构的维吾尔族人脸图像;然后,经POEM计算维吾尔族人脸图像的特征量得到其相应的POEM直方图并把直方图级联在一起,作为该中心特征点的POEM纹理直方图,得到维吾尔族人脸特征点的纹理特征信息;最后,采用深度学习算法进行分类识别。本文通过实验提出的算法,在自建的维吾尔族人脸库中能够进一步提高其人脸识别率,在维吾尔族人脸数据库中其运算速度也有很大提高。实验结果表明,该算法尤其是在维吾尔族人脸数据库中拥有较好的识别精度,具有很强的鲁棒性,特别是在光照以及部分遮挡下具有很强的优势。     

基于面对象数据模型的GIS空间数据库应用研究

在比较几种传统数据模型的优缺点基础上，提出了面向对象数据模型，并分析了采用面向对象数据模型建立GIS空间数据库的现实意义和优势。分析比较了三种构建面向对象GIS空间数据库的实现方式并讨论了面向对象GIS空间数据库在两个方面的应用：一是构建面向对象影像、矢量、DEM集成化GIS空间数据库；二是构建对象一关系型数据库管理系统（ORDBMS）。最后，展望了GIS数据库发展的新趋势。     

基于面向对象数据模型的GIS空间数据库应用研究

在比较几种传统数据模型的优缺点基础上,提出了面向对象数据模型,并分析了采用面向对象数据模型建立GIS空间数据库的现实意义和优势.分析比较了三种构建面向对象GIS空间数据库的实现方式并讨论了面向对象GIS空间数据库在两个方面的应用:一是构建面向对象影像、矢量、DEM集成化GIS空间数据库;二是构建对象一关系型数据厍管理系统(ORDBMS).最后,展望了GIS数据库发展的新趋势.     

Texture image retrieval using new rotated complex wavelet filters.

A new set of two-dimensional (2-D) rotated complex wavelet filters (RCWFs) are designed with complex wavelet filter coefficients, which gives texture information strongly oriented in six different directions (45 degrees apart from complex wavelet transform). The 2-D RCWFs are nonseparable and oriented, which improves characterization of oriented textures. Most texture image retrieval systems are still incapable of providing retrieval result with high retrieval accuracy and less computational complexity. To address this problem, we propose a novel approach for texture image retrieval by using a set of dual-tree rotated complex wavelet filter (DT-RCWF) and dual-tree-complex wavelet transform (DT-CWT) jointly, which obtains texture features in 12 different directions. The information provided by DT-RCWF complements the information generated by DT-CWT. Features are obtained by computing the energy and standard deviation on each subband of the decomposed image. To check the retrieval performance, texture database D1 of 1856 textures from Brodatz album and database D2 of 640 texture images from VisTex image database is created. Experimental results indicates that the proposed method improves retrieval rate from 69.61% to 77.75% on database D1, and from 64.83% to 82.81% on database D2, in comparing with traditional discrete wavelet transform based approach. The proposed method also retains comparable levels of computational complexity.     

Trigger inheritance and overriding in an active object databasesystem

An active database is a database in which some operations are automatically executed when specified events happen and particular conditions are met. Several systems supporting active rules in an object oriented data model have been proposed. However, several issues related to the integration of triggers with object oriented modeling concepts have not been satisfactorily addressed. We discuss issues related to trigger inheritance and refinement in the context of the Chimera active object oriented data model. In particular, we introduce a semantics for an active object language that takes into account trigger inheritance and supports trigger overriding. Moreover, we state conditions on trigger overriding ensuring that trigger semantics is preserved in subclasses     

基于方向边缘幅值的尺度块LBP人脸识别

针对方向边缘幅值模式（POEM）忽略了块与块之间的像素问题,提出一种基于方向边缘幅值的尺度块LBP人脸识别方法。该方法首先用梯度算子提取出人脸的方向图和幅值图,将具有相同量化方向上的幅值累加,然后利用尺度块LBP算子提取每幅累加幅值图的分块直方图特征,并将所有直方图特征串联起来作为最终的识别特征,最后采用WPCA降维方法提高算法的有效性。实验结果表明,该算法的鲁棒性高于其他对比算法,运用降维处理后能以较低的特征维数达到良好的识别性能。     

An object-oriented database system Jasmine: implementation,application, and extension

We have devised an object oriented DBMS called Jasmine for advanced applications. The paper describes the implementation, application and extension of Jasmine in detail. We focus on the impact of the design of its object oriented model and language on database implementation technology. We describe what part of traditional relational database technology we extend to handle object oriented features such as object identifiers, complex objects, class hierarchies, and methods. We introduce nested relations to efficiently store and access clustered complex objects. We use hash based methods to efficiently access nonclustered complex objects. We provide user defined functions directly evaluated on page buffers to efficiently process method invocation. We devise object oriented optimization of queries including class hierarchies, complex objects, and method invocation. We incorporate dedicated object buffering to allow efficient access to objects through object identifiers. We also describe nontrivial applications of Jasmine and discuss the validity of object oriented databases. We focus on a constraint management facility, which can be implemented by taking advantage of the extensibility of Jasmine. The facility includes constraint rules, called design goals, for automatic database population required by engineering applications. Finally, we describe a view facility for schema integration also needed by engineering applications in distributed environments. We focus on how we extend Jasmine to implement the facility     

Constructing Geographic Digital Libraries using a Hypermedia Framework

This paper presents an object oriented hypermedia database framework for designing and building digital libraries, which are treated as enhanced hypermedia applications. It is based on combining and extending results from two domains: the navigation characteristics of hypertext systems, and the view mechanism and the persistent storage management facility of an object oriented database management system. As a result, users can alternate between two integrated types of interaction modes. The hypertext dimension of the framework allows navigation via static and dynamic hyperlinks; the object oriented database support enables querying by content and metadata management. The framework includes still a digital library design methodology that guides the implementation of digital libraries over the OODBMS. This proposal integrates hypermedia and DL concepts to a database environment, being instantiated on the realm of geographic data.     

Fingerprint classification using a feedback-based line detector

We present a fingerprint classification algorithm in this paper. This algorithm classifies a fingerprint image into one of the five classes: Arch, Left loop, Right loop, Whorl, and Tented arch. We use a new low-dimensional feature vector obtained from the output of a novel oriented line detector presented here. Our line detector is a co-operative dynamical system that gives oriented lines and preserves multiple orientations at points where differently oriented lines meet. Our feature extraction process is based on characterizing the distribution of orientations around the fingerprint. We discuss three different classifiers: support vector machines, nearest-neighbor classifier, and neural network classifier. We present results obtained on a National Institute of Standards and Technology (NIST) fingerprint database and compare with other published results on NIST databases. All our classifiers perform equally well, and this suggests that our novel line detection and feature extraction process indeed captures all the crucial information needed for classification in this problem.     

时态数据的变粒度分段存储策略及其效益分析S

根据时态数据库用户对数据厚今薄古的需求特点,该文提出变粒度分段存储技术,将一个对象的历史分为3个时期,分介质、变粒度存储.文章讨论了分段存储的特殊数据结构、时代转移算法和压缩采样算法.基于微机实用参数的定量分析表明,这一技术将时态存储密度和时态查询速度提高了一个数量级.     

时态数据的变粒度分段存储策略及其效益分析

根据时态数据库用户对数据厚今薄古的需求特点,该文提出变粒度分段存储技术,将一个对象的历史分为3个时期,分介质、变粒度存储.文章讨论了分段存储的特殊数据结构、时代转移算法和压缩采样算法.基于微机实用参数的定量分析表明,这一技术将时态存储密度和时态查询速度提高了一个数量级.     

多线程技术的研究与应用

现代主流操作系统已经广泛采用了多线程技术．首先论述了多线程的基本概念,然后着重分析了３种主要的多线程实现方案：内核绵线程、用户级线程和混合策略,然后介绍了多线程技术的应用．还结合面向对象数据库管理系统ＮＯＤＢＭＳ的实现,介绍了如何应用多线程技术实现多事务处理,并提出了一个基于多线程技术实现的对象式数据库查询优化算法、该算法取得了较好的效果。     

多比例尺下的三维GIS细节层次可视化技术

In this paper ,by investigating leve!yof detail in 3D GIS,we integrate generalization techniqueswith 3D visualization techniques on the basis of object oriented database. In order to improve the perfor-mance of database access ,we investigate the access structure based on modified reactive tree and analyzethe detailed method of representing level of detail. This approach visualizes 3I) object with object-orient-ed database and integrates generalization with 3I) visualization techniques ,3D G-IS is expected to achievebetter performance of query and photo-realistic visualization at multi-scale。     

RDWT domain statistical watermark detector using FRHFMs magnitudes and bivariate Cauchy-Rayleigh distribution

Imperceptibility, robustness and data payload, which are complimentary to each other, are widely considered as the three main properties vital for any image watermarking systems. It is a challenging work to design a statistical model-based multiplicative watermarking scheme for achieving the tradeoff among three main properties. In this paper, we propose a novel statistical image watermarking scheme by modeling local redundant discrete wavelet transform (RDWT) and fast Radial harmonic Fourier moments (FRHFMs) magnitudes with bivariate Cauchy-Rayleigh distribution. Our image watermarking scheme consists of two parts, namely, embedding and detection. In the embedding process, RDWT is firstly performed on the host image and RDWT highpass subbands are divided into non-overlapping blocks. Then FRHFMs are computed on RDWT coefficient blocks. And finally, the watermark signal is inserted into robust RDWT-FRHFMs magnitudes through a non-linear multiplicative approach. In the detection process, robust local RDWT-FRHFMs magnitudes are firstly modeled by employing bivariate Cauchy-Rayleigh distribution, which can capture accurately both marginal distributions and strong dependencies of local RDWT-FRHFMs magnitudes. Statistical model parameters are then estimated effectively by the method of logarithmic cumulants (MoLC) approach. And finally, an image watermark detector for multiplicative watermarking is developed using bivariate Cauchy-Rayleigh model and locally most powerful (LMP) test. Also, we utilize the bivariate Cauchy-Rayleigh model to derive the closed-form expressions for the watermark detector. After performance testing and comparison with the experimental results of existing methods, the proposed statistical image watermarking method has achieved relatively ideal results in terms of robustness, imperceptibility and data payload.

     

MDARTS: a multiprocessor database architecture for hard real-timesystems

Complex real time systems need databases to support concurrent data access and provide well defined interfaces between software modules. However, conventional database systems and prior real time database systems do not provide the performance or predictability needed by high speed, hard real time applications. The authors designed, implemented, and evaluated an object oriented database system called MDARTS (Multiprocessor Database Architecture for Real Time Systems). MDARTS avoids the client server overhead of most prior real time database systems and object oriented, real time systems by moving transaction execution into application tasks. By eliminating these sources of overhead and focusing on basic data management services for control systems (data sharing, serializable transactions, and multiprocessor support), the MDARTS prototype provides hard real time transaction times approximately three orders of magnitude faster than prior real time database systems. MDARTS ensures bounded locking delay by disabling preemption when a transaction is waiting for a lock, and hence, allows for the estimation of worst case transaction execution times. Another contribution of MDARTS is that it supports explicit declarations of real time requirements and semantic constraints within application code. The MDARTS library examines these declarations at application initialization time and attempts to construct objects that are compatible with the requirements. Besides local shared memory transactions with hard real time response time guarantees, MDARTS also supports remote transactions that use remote procedure calls for data access with less stringent timing constraints. The MDARTS prototype is implemented in C++ and it runs on VME based multiprocessors and Sun workstations     

Quality of experience in distributed databases

This paper proposes an approach to improve the level of Quality of Experience (QoE) that distributed database systems provide. Quality of Experience is a measure of users?? satisfaction when using a certain service or application. Therefore, the main objective of this paper is to provide mechanisms to increase users?? satisfaction when accessing distributed database systems. In traditional database systems, users cannot specify execution-related constraints. Then, the database system cannot evaluate if user expectations are satisfied and neither the system can take corrective actions when necessary. In this work, we present the QoE-oriented distributed database system (QoE-DDB). It allow users to specify Data Access Requirements (DARs) and aims to please users by satisfying the DARs they define. We define a set of types of Data Access Requirements and propose some SQL extensions that enable users to specify execution-related requirements. Proposed types of DARs include execution deadline and priority, execution start and finish times, data availability and freshness degrees, and disconnected execution mode. In our QoE-DDB, each user??s command is transformed into one or more tasks that are executed by data services. Community modules and local data services negotiate Service Level Objectives (SLOs) for each task, which improves the system??s dependability. We propose both QoE-oriented scheduling and dynamic data placement strategies. Proposed architecture and scheduling strategies enable the system to be used in a wide range of distributed environments, from tightly-coupled homogeneous environments (e.g. composed by off-the-shelf computers connected by a LAN) to highly heterogeneous and geographically distributed systems, where data services have some degree of autonomy. Traditional performance indicators (e.g. throughput and response time) are not adequate to measure the QoE a system provides. We also propose some specialized Key Performance Indicators (KPIs) to estimate the QoE level a database system provides. Finally, we present experimental results obtained through the use of benchmark data and queries together with a prototype that implements proposed strategies. In our experiments, we consider realistic scenarios and compare proposed scheduling strategies with their best-effort oriented counterparts. Obtained results prove the importance of our QoE-oriented approach.     

Rotation-invariant texture image retrieval using rotated complex wavelet filters.

This paper proposes a novel approach for rotation-invariant texture image retrieval by using set of dual-tree rotated complex wavelet filter (DT-RCWF) and DT complex wavelet transform (DT-CWT) jointly, which obtains texture features in 12 different directions. Two-dimensional RCWFs are nonseparable and oriented, which improves characterization of oriented textures. Robust and efficient isotropic rotationally invariant features are extracted from DT-RCWF and DT-CWT decomposed subbands. This paper demonstrates the effectiveness of this new set of features on four different sets of rotated and nonrotated databases. Experimental results indicate that the proposed method improves retrieval accuracy from 83.17% to 93.71% on a small size (208 images) nonrotated database D1, from 82.71% to 90.86% on a small size (208 images) rotated database D2, from 72.18% to 76.09% on a medium-size (640 images) rotated database D3, and from 64.17% to 78.93% on a large size (1856 images) rotated database D4, compared with the discrete wavelet transform-based approach. New method also retains comparable levels of computational complexity.