用于3D模型检索的扩展距离球面调和表达

使用光线投射方法对3D模型定义了一个对应的球函数--扩展距离球函数,然后引入了球面调和分析方法,构造了一种对于平移、缩放和旋转变换具有不变性的特征向量,并用于基于形状的3D模型检索中.与基于向径方法结合,提高了检索的效果,扩大了应用范围.     

基于谐波结构信息的自动音乐标注方法

根据同类乐器音色相似的特点,提出了一种基于谐波结构信息的自动音乐标注方法.该方法事先提取一类乐器中某一件乐器的谐波结构信息.根据输入信号选择合适的不谐和系数、频率误差系数,结合谐波结构信息构造同类未知乐器的响度谱,然后采用截断完全最小二乘法实现对同类未知乐器音乐的标注.对钢琴音乐的实验证明,该方法不仅能对未知乐器的音乐进行标注,取得较好的性能,还可辨别音符的响度强弱.     

Unsupervised Single-Channel Music Source Separation by Average Harmonic Structure Modeling

Source separation of musical signals is an appealing but difficult problem, especially in the single-channel case. In this paper, an unsupervised single-channel music source separation algorithm based on average harmonic structure modeling is proposed. Under the assumption of playing in narrow pitch ranges, different harmonic instrumental sources in a piece of music often have different but stable harmonic structures; thus, sources can be characterized uniquely by harmonic structure models. Given the number of instrumental sources, the proposed algorithm learns these models directly from the mixed signal by clustering the harmonic structures extracted from different frames. The corresponding sources are then extracted from the mixed signal using the models. Experiments on several mixed signals, including synthesized instrumental sources, real instrumental sources, and singing voices, show that this algorithm outperforms the general nonnegative matrix factorization (NMF)-based source separation algorithm, and yields good subjective listening quality. As a side effect, this algorithm estimates the pitches of the harmonic instrumental sources. The number of concurrent sounds in each frame is also computed, which is a difficult task for general multipitch estimation (MPE) algorithms.     

Compact Representation of Spectral BRDFs Using Fourier Transform and Spherical Harmonic Expansion

This paper proposes a compact method to represent isotropic spectral BRDFs. In the first step, we perform a Fourier transform in the wavelength dimension. The resulting Fourier coefficients of the same order depend on three angles: the polar angle of the incident light, and the polar and azimuth angles of the outgoing light. In the second step, given an incident light angle, when the Fourier coefficients of the same order have an insensitive dependency on the outgoing direction, we represent these Fourier coefficients using a linear combination of spherical harmonics. Otherwise, we first decompose these Fourier coefficients into a smooth background that corresponds to diffuse component and a sharp lobe that corresponds to specular component. The smooth background is represented using a linear combination of spherical harmonics, and the sharp lobe using a Gaussian function. The representation errors are evaluated using spectral BRDFs obtained from measurement or generated from the Phong model. While maintaining sufficient accuracy, the proposed representation method has achieved data compression over a hundred of times. Examples of spectral rendering using the proposed method are also shown.     

Representation for knot-tying tasks

The learning from observation (LFO) paradigm has been widely applied in various types of robot systems. It helps reduce the work of the programmer. However, the applications of available systems are limited to manipulation of rigid objects. Manipulation of deformable objects is rarely considered, because it is difficult to design a method for representing states of deformable objects and operations against them. Furthermore, too many operations are possible on them. In this paper, we choose knot tying as a case study for manipulating deformable objects, because the knot theory is available and the types of operations possible in knot tying are limited. We propose a knot planning from observation (KPO) paradigm, a KPO theory, and a KPO system.     

A Representation Theorem for MV-algebras

An MV-pair is a pair (B,G) where B is a Boolean algebra and G is a subgroup of the automorphism group of B satisfying certain conditions. Let ~ _G be the equivalence relation on B naturally associated with G. We prove that for every MV-pair (B,G), the effect algebra B/ ~ _G is an MV-effect algebra. Moreover, for every MV-effect algebra M there is an MV-pair (B,G) such that M is isomorphic to B/ ~ _G . This research is supported by grant VEGA G-1/3025/06 of MŠ SR, Slovakia and by the Science and Technology Assistance Agency under the contract No. APVT-51-032002.     

主题关注网络的表示学习

针对异质网络表示学习仅从结构方面考虑社交关系而忽略语义这一问题,结合用户间的社交关系和用户对主题的偏好两个方面,提出基于主题关注网络的表示学习算法。首先,针对主题关注网络的特点,结合集对分析理论的同异反（确定与不确定）思想,给出转移概率模型;然后,在转移概率模型的基础上提出了一种基于两类节点的随机游走算法,以得到相对高质量的随机游走序列;最后,基于序列中两类节点建模得到主题关注网络的嵌入向量空间表示。理论分析和在豆瓣数据集上的实验结果表明,结合转移概率模型的随机游走算法能更全面地分析网络中节点的连接关系,当划分社区的个数为13时,所提算法的模块度为0.699 8,相比metapath2vec算法提高了近5%,可以更详细地捕获网络中的信息。     

一种针对隐式反馈推荐系统的表征学习方法

基于邻域的top-◢N◣推荐算法利用隐式反馈数据建立排序模型,其算法性能严重依赖于相似度函数的表现。传统相似性度量函数在隐式反馈数据上会遇到数据过于稀疏和维数过高两个问题,稀疏数据不利于推荐模型选取光滑的邻域,过高的数据维数会导致维数灾难问题,导致推荐算法表现较差。为此提出一种基于表征学习方法的推荐算法,改进算法实现了基于二部图网络的多目标节点表征学习方法,在节点表征中通过嵌入不同层次的网络结构信息和适合推荐任务的次序信息来提升推荐性能。三个不同规模真实数据集上的实验结果表明,该算法相较于常用的基于隐式反馈的推荐模型具有更高的准确率和召回率,特别是针对大规模数据集能够有效缓解矩阵稀疏性问题和维数灾难问题,提高推荐性能。     

适于点绘制的图形表示方法的研究

在基于点的图形绘制技术中,作为绘制基本元素的点不是数学上无意义的点,它有位置、形状、大小等属性,如何基于点有效地表示图形将影响图形绘制的效果。论文研究了基于点的图形表示方法——单纯基于点的表示、圆球表示和表面足迹表示,重点讨论了足迹表示法的关键问题——足迹大小的求解,提出了一种基于协方差分析的表面足迹的求解方法,结果表明这种方法是有效的。     

Representation theory for default logic

Default logic can be regarded as a mechanism to represent families of belief sets of a reasoning agent. As such, it is inherently second-order. In this paper, we study the problem of representability of a family of theories as the set of extensions of a default theory. We give a complete solution to the problem of representability by means of default theories with finite set of defaults, and by means of normal default theories. We obtain partial results on representability by arbitrary (infinite, non-normal) default theories. We construct examples of denumerable families of non-including theories that are not representable. We also study the concept of equivalence between default theories. This revised version was published online in June 2006 with corrections to the Cover Date.     

Labeling Schemes for Tree Representation

This paper deals with compact label-based representations for trees. Consider an n-node undirected connected graph G with a predefined numbering on the ports of each node. The all-ports tree labeling ℒ _all gives each node v of G a label containing the port numbers of all the tree edges incident to v. The upward tree labeling ℒ _up labels each node v by the number of the port leading from v to its parent in the tree. Our measure of interest is the worst case and total length of the labels used by the scheme, denoted M _up (T) and S _up (T) for ℒ _up and M _all (T) and S _all (T) for ℒ _all . The problem studied in this paper is the following: Given a graph G and a predefined port labeling for it, with the ports of each node v numbered by 0,…,deg (v)−1, select a rooted spanning tree for G minimizing (one of) these measures. We show that the problem is polynomial for M _up (T), S _up (T) and S _all (T) but NP-hard for M _all (T) (even for 3-regular planar graphs). We show that for every graph G and port labeling there exists a spanning tree T for which S _up (T)=O(nlog log n). We give a tight bound of O(n) in the cases of complete graphs with arbitrary labeling and arbitrary graphs with symmetric port labeling. We conclude by discussing some applications for our tree representation schemes. A preliminary version of this paper has appeared in the proceedings of the 7th International Workshop on Distributed Computing (IWDC), Kharagpur, India, December 27–30, 2005, as part of Cohen, R. et al.: Labeling schemes for tree representation. In: Proceedings of 7th International Workshop on Distributed Computing (IWDC), Lecture Notes of Computer Science, vol. 3741, pp. 13–24 (2005). R. Cohen supported by the Pacific Theaters Foundation. P. Fraigniaud and D. Ilcinkas supported by the project “PairAPair” of the ACI Masses de Données, the project “Fragile” of the ACI Sécurité et Informatique, and by the project “Grand Large” of INRIA. A. Korman supported in part by an Aly Kaufman fellowship. D. Peleg supported in part by a grant from the Israel Science Foundation.     

SCSI子系统中间层多启动互连多路径I/O的存储方式的研究

面对当前应用对现代存储的高性能以及可用性、可靠性的新的要求,在Multi—Initiator—Uni—Port的基础之上提出了SCSI中间层多启动互连多路径I／O的存储方式．它能够在Multi—Initiator—Uni—Port的连接中对同一个Target端口采用不同的I／O路径进行存储,减少了由于单路径I／O传输错误导致系统单点失效的可能性,增强了存储系统的可用性和可靠性;同时,这种存储方式还能够很好地平衡系统的I／O负载,提高系统的吞吐率,提供比传统单路径更好的传输性能．在Linux2．4内核中的SCSI子系统的基础之上实现了这种存储方式,向系统屏蔽了SCSI子系统中的设备具体细节,并且不依赖于SCSI上层的实现,减少了对系统内核的资源占有率,提高了SCSI底层的执行效率．分析了SCSI中间层多启动互连多路径I／O的存储方式的原理,并且将iSCSI的体系结构应用到它的模拟测试中,得到了R—R路径选择分配策略的性能临界点,取得了令人满意的结果．     

Time-Scale Atoms Chains for Transients Detection in Audio Signals

This paper presents a novel approach for the extraction of the transients content of audio signals, usually represented as superposition of stationary, transient, and stochastic components. The proposed model exploits the predictable and peculiar time-scale behavior of transients by modeling them as superposition of suitable wavelet atoms. These latter allow to predict transients information even at scales where the tonal component is dominant. In this way it is possible to avoid, if required, the pre-analysis of the tonal component. Extensive experimental results show that the proposed model achieves good performances with a moderate computational effort and without any user's dependence.      

Harmonic Embeddings for Linear Shape Analysis

We present a novel representation of shape for closed contours in ℝ² or for compact surfaces in ℝ³ explicitly designed to possess a linear structure. This greatly simplifies linear operations such as averaging, principal component analysis or differentiation in the space of shapes when compared to more common embedding choices such as the signed distance representation linked to the nonlinear Eikonal equation. The specific choice of implicit linear representation explored in this article is the class of harmonic functions over an annulus containing the contour. The idea is to represent the contour as closely as possible by the zero level set of a harmonic function, thereby linking our representation to the linear Laplace equation. We note that this is a local represenation within the space of closed curves as such harmonic functions can generally be defined only over a neighborhood of the embedded curve. We also make no claim that this is the only choice or even the optimal choice within the class of possible linear implicit representations. Instead, our intent is to show how linear analysis of shape is greatly simplified (and sensible) when such a linear representation is employed in hopes to inspire new ideas and additional research into this type of linear implicit representations for curves. We conclude by showing an application for which our particular choice of harmonic representation is ideally suited.