A Statistical Comparison of Two Hidden Surface Techniques: the Scan-line and Z-buffer Algorithms

This paper compares two image space hidden surface removal algorithms for polygonal scenes. These are the z-buffer and scan-line algorithms. There is first an overview of each algorithm, followed by a simulation experiment, designed to compare the number of polygons per second which can be rendered by each algorithm. The simulation varies the number of polygons in the scene, and the size and distribution of polygons over the display. The results suggest that the z-buffer is preferred for a large enough number of polygons, however, smaller polygons and uniform distribution of polygons favour the scan-line approach. The analysis does not take into account the complexity of the shading rule, which is likely also to favour the scan-line method.     

几种常用嵌入式技术应用特点的比较

随着嵌入式系统的应用范围越来越广泛,越来越多的人开始学习嵌入式系统相关技术或从事相关工作.但是现有的嵌入式技术种类繁多,对于初学者来说,容易混淆.从器件的特性、应用优势、开发特点等方面介绍了几种常用嵌入武技术,并做了相应比较.     

图象分割评价技术分类和比较

本文对图象分割评价，特别是评价方法和评价准则的进展，作了一个综述，现已提出的多数分割评价方法可分为直接法和间接法，直接法研究分割算法本身，面间接法根据分割图象来评价算法的性能。直接法和间接法都需要借助一定的评价准则来进行。本文对已提出的各种准则进行了分类与分析比较，并对常用的评价准则进行了实验比较，通过分析其性能表现排出了它们的优劣次序。本研究为在实际中正确地应用不同的评价方法提出了依据并指出了若干进一步研究的方向。     

An Evaluation of Visualization Techniques to Illustrate Statistical Deformation Models

As collections of 2D/3D images continue to grow, interest in effective ways to visualize and explore the statistical morphological properties of a group of images has surged. Recently, deformation models have emerged as simple methods to capture the variability and statistical properties of a collection of images. Such models have proven to be effective in tasks such as image classification, generation, registration, segmentation, and analysis of modes of variation. A crucial element missing from most statistical models has been an effective way to summarize and visualize the statistical morphological properties of a group of images. This paper evaluates different visualization techniques that can be extended and used to illustrate the information captured by such statistical models. First, four illustration techniques are described as methods to summarize the statistical morphological properties as captured by deformation models. Second, results of a user study conducted to compare the effectiveness of each visualization technique are presented. After comparing the performance of 40 subjects, we found that statistical annotation techniques present significant benefits when analyzing the structural properties of a group of images.     

A Review of Statistical Language Processing Techniques

We present a review of some recently developed techniques in the field of natural language processing. This area has witnessed a confluence of approaches which are inspired by theories from linguistics and those which are inspired by theories from information theory: statistical language models are becoming more linguistically sophisticated and the models of language used by linguists are incorporating stochastic techniques to help resolve ambiguities. We include a discussion about the underlying similarities between some of these systems and mention two approaches to the evaluation of statistical language processing systems.     

A Subjective Evaluation of Texture Synthesis Methods

This paper presents the results of a user study which quantifies the relative and absolute quality of example‐based texture synthesis algorithms. In order to allow such evaluation, a list of texture properties is compiled, and a minimal representative set of textures is selected to cover these. Six texture synthesis methods are compared against each other and a reference on a selection of twelve textures by non‐expert participants (N = 67). Results demonstrate certain algorithms successfully solve the problem of texture synthesis for certain textures, but there are no satisfactory results for other types of texture properties. The presented textures and results make it possible for future work to be subjectively compared, thus facilitating the development of future texture synthesis methods.     

A Comparison of Antialiasing Techniques

Three antialiasing techniques were applied to a scene of moderate complexity. Early results suggest that prefiltering is still the most computationally effective method.     

Fuzzy Techniques for Subjective Workload-Score Modeling Under Uncertainties

This paper deals with the development of a computer model to estimate the subjective workload score of individuals by evaluating their heart-rate (HR) signals. The identification of a model to estimate the subjective workload score of individuals under different workload situations is too ambitious a task because different individuals (due to different body conditions, emotional states, age, gender, etc.) show different physiological responses (assessed by evaluating the HR signal) under different workload situations. This is equivalent to saying that the mathematical mappings between physiological parameters and the workload score are uncertain. Our approach to deal with the uncertainties in a workload-modeling problem consists of the following steps: 1) The uncertainties arising due the individual variations in identifying a common model valid for all the individuals are filtered out using a fuzzy filter; 2) stochastic modeling of the uncertainties (provided by the fuzzy filter) use finite-mixture models and utilize this information regarding uncertainties for identifying the structure and initial parameters of a workload model; and 3) finally, the workload model parameters for an individual are identified in an online scenario using machine learning algorithms. The contribution of this paper is to propose, with a mathematical analysis, a fuzzy-based modeling technique that first filters out the uncertainties from the modeling problem, analyzes the uncertainties statistically using finite-mixture modeling, and, finally, utilizes the information about uncertainties for adapting the workload model to an individual's physiological conditions. The approach of this paper, demonstrated with the real-world medical data of 11 subjects, provides a fuzzy-based tool useful for modeling in the presence of uncertainties.      

应用CorelDraw画图的若干技巧

对教学的更高要求,决定了必须用清晰的图形来表达问题。本文介绍了如何应用CoreiDraw软件制作出工程矢量图形,以及在制作中遇到的问题及解决的方法。     

Statistical Scheduling of Offline Comparative Subjective Evaluations for Real-Time Multimedia

In this paper, we study the statistical scheduling of offline subjective tests for evaluating alternative control schemes in real time multimedia applications. These applications are characterized by multiple counteracting objective quality metrics (such as delay and signal quality) that can be affected by various control schemes. However, the trade-offs among these metrics with respect to the subjective preferences of users are not defined. As a result, it is difficult to select the proper control schemes that lead to the best subjective quality at run time. Since subjective tests are expensive to conduct and the number of possible control schemes and run-time conditions is prohibitively large, it is important that a minimum number of such tests be conducted offline, and that the results learned can be generalized to unseen conditions with statistical confidence. To this end, we study in this paper efficient algorithms for scheduling a sequence of subjective tests, while leaving the generalization of limited offline subjective tests to guide the operation of the control schemes at run time to a future paper. Using Monte Carlo simulations, we verify the robustness of our algorithms in terms of their accuracy and efficiency.     

A Comparison between SAT and CSP Techniques

The aim of this paper is to establish a connection between the propositional logic and the constraint based reasoning frameworks. This work is based on a translation of the satisfiability problem (SAT) into the binary constraint-satisfaction problem (CSP). The structure of the SAT problem and its associated CSP are then exploited together for characterizing tractable SAT problems, increasing the effectiveness of the classical reduction rules: unit clause and monotone literal rules, and expressing the arc and path consistency concepts with logical inference rules. This study leads to compare the behaviors of the DP and MAC procedures for solving respectively a SAT instance and its binary CSP expression.     

数据挖掘中的统计方法概述

统计方法有成熟的数学基础，可以很好的对数据进行解释，在数据挖掘中有着大量的运用。文章回顾了数据挖掘中常用的统计方法，包括传统的统计方法(回归分析、主成分分析、判别分析和聚类分析)和其他一些非机器学习的方法(模糊集、粗糙集和统计学习理论)，分析了各种统计方法的优缺点。     

Evaluation of Current Documents Image Denoising Techniques: A Comparative Study

The research to come out with effective and noise-free images is still fresh despite several years’ efforts. Even though, recently, several methods have been proposed, each approach has its own merits and limitations. Moreover, outstanding performances are exhibited for the tailored applications but fail in general and create several flaws and blur images of fine structures. The purpose of this study is to compare achievements thus far in the area of nonnatural documents image denoising approaches. Accordingly, existing techniques are organized into nonhomogeneous categories and detailed comparison is exhibited with examples. Finally, remaining problems and possible future directions in the domain of document images denoising are suggested.     

浅谈入侵检测中的几种常用技术

入侵检测系统作为防火墙的合理补充,已经在网络安全中起着非常重要的作用。该文从入侵检测技术的定义出发,探讨入侵检测的基本原理,详细探讨了入侵检测中几种常用的技术。     

几种典型的HMI统计报表实现方法

统计报表在工业生产型企业中应用非常广泛。不管是基于DCS/PLC的PCS控制层还是生产执行MES层,统计分析报表都是重要功能,而且随着企业用户管理水平和技术能力的提升,对如何挖掘历史数据来提高生产和管理效率的期望也更加迫切。对市场上常见HMI产品中的统计报表功能的实现方法进行比较分析,指出不同实现方法的优劣性和适用场合,为更好的设计开发相关的产品提供借鉴意义。     

几种高速无线接入Internet网新技术

介绍目前热门ＤＢＳ、 ＭＭＤＳ、ＬＭＤＳ、ＧＰＲＳ的Ｉｎｔｅｒｎｅｔ网高速无线接 入网方式的优势及其应用前景。     

基于色度裁减技术的评价方法

该文介绍了一种基于色度裁减技术的评价方法,用三种不同的目标域来检测目标色域模型对不同匹配技术的影响。与以往方法的不同之处在于本文采用的是通过对单一颜色的比较推断出衡量出影响色相的主要因素。虽然连续色度裁减技术保持亮度不变,整体上是最优的,但也有例外的情况。实验结果指出了在全局趋势和特定例外情况下的一种折中方法,对于图像中的局部色域和目标色域有一定的借鉴意义。     

A Psychophysical Evaluation of Inverse Tone Mapping Techniques

In recent years inverse tone mapping techniques have been proposed for enhancing low-dynamic range (LDR) content for a high-dynamic range (HDR) experience on HDR displays, and for image based lighting. In this paper, we present a psychophysical study to evaluate the performance of inverse (reverse) tone mapping algorithms. Some of these techniques are computationally expensive because they need to resolve quantization problems that can occur when expanding an LDR image. Even if they can be implemented efficiently on hardware, the computational cost can still be high. An alternative is to utilize less complex operators; although these may suffer in terms of accuracy. Our study investigates, firstly, if a high level of complexity is needed for inverse tone mapping and, secondly, if a correlation exists between image content and quality. Two main applications have been considered: visualization on an HDR monitor and image-based lighting.