基于非负矩阵分解的鲁棒哈希函数验证性研究

矩阵分解是实现大规模数据处理与分析的一种有效工具。矩阵的非负矩阵分解NMF(Non-Negative Matrix Factorization)变换是一种正交变换,是在矩阵中所有元素均为非负的条件下对其实现的非负分解。鲁棒哈希技术利用密钥提取多媒体内容的某些鲁棒特征,通过进一步压缩产生哈希值,通过比较跟随媒体内容传送来的哈希和接收端产生的哈希,实现对媒体内容的真实性认证。     

Spatial co-location pattern discovery without thresholds

Spatial co-location pattern mining discovers the subsets of features whose events are frequently located together in geographic space. The current research on this topic adopts a threshold-based approach that requires users to specify in advance the thresholds of distance and prevalence. However, in practice, it is not easy to specify suitable thresholds. In this article, we propose a novel iterative mining framework that discovers spatial co-location patterns without predefined thresholds. With the absolute and relative prevalence of spatial co-locations, our method allows users to iteratively select informative edges to construct the neighborhood relationship graph until every significant co-location has enough confidence and eventually to discover all spatial co-location patterns. The experimental results on real world data sets indicate that our framework is effective for prevalent co-locations discovery.     

MeeGo嵌入式操作系统的研究及应用开发

论述了在Linux平台下搭建MeeGo嵌入式操作系统应用程序开发环境的方法和步骤,给出了使用Qt Creator工具开发MeeGo应用程序的流程。通过在Atom D510嵌入式实验平台和QEMU虚拟机下安装MeeGo操作系统,设计实现了具有3D操作界面且集成办公、娱乐、微博聊天、地图查询四大模块为一体的应用程序。该应用程序具有友好的人机交互界面和良好的可移植性,体现了"一次编写,到处运行"的理念。     

基于精简星座鉴相的大频偏16-APSK信号载波同步

为了增大对16-APSK信号的鉴相范围,提高环路捕获带宽,提出了在环路捕获阶段使用精简星座鉴相、在捕获完成后使用混合NDA/DD鉴相的载波同步结构。这种结构在实现了环路捕获带宽增加的同时,仍然保持了混合NDA/DD法实现简单、与符号判决单元无耦合、运算速度快的优点。仿真结果验证了使用精简星座鉴相后环路捕获带宽的增加。     

Auto-scanning and visualizing system for the acoustic field of transducer

This paper presents an automatic scanning and visualizing system for ultrasound field of a planar piston transducer. This system consists of a water tank with wedge absorber, stepper motors driver, system controller, a planar piston transducer, a needle-type hydrophone and data processing software. Our software realizes the processing and displaying of ultrasonic data, which are acquired by adjusting accurately positions of the hydrophone and transducer that are driven by stepper motors. And the ultrasonic field is represented by employing 1D, 2D or 3D graphs of data, respectively. Experimental results show that this auto-scanning and visualizing system provides a more spatial structure of ultrasonic field and reveals a more characteristic of ultrasonic beam radiated by the planar piston transducer.     

The mediating effect of organizational culture and knowledge sharing on transformational leadership and Enterprise Resource Planning systems success: An empirical study in China

Senior leadership has been identified as a critical factor in fostering Enterprise Resource Planning (ERP) systems success, however, the specific impact mechanism of transformational leadership on ERP success is still largely unknown. Based on organizational culture theory and knowledge based view, this study developed a theoretical model to explore the mediating effect of organizational culture and knowledge sharing on transformational leadership and ERP success. Data was collected from 115 IS executives and 413 ERP end users in 115 organizations in China. Partial Least Squares (PLS) analysis results suggest that transformational leadership is directly related with all the four types of organizational culture – development culture, group culture, hierarchical culture and rational culture, and is indirectly related with knowledge sharing and ERP success. Specifically, development culture has direct impact on ERP success, while hierarchical culture, group and rational culture are indirectly related with ERP success, mediated by explicit and tacit knowledge sharing. The research findings can provide guidelines for the top executives to facilitate appropriate organizational culture, so as to foster ERP knowledge sharing and achieve business benefits with the assimilation of ERP systems.     

Fusing ant colony optimization with Lagrangian relaxation for the multiple-choice multidimensional knapsack problem

The multiple-choice multidimensional knapsack problem (MMKP) concerns a wide variety of practical problems. It is strongly constrained and NP-hard; thus searching for an efficient heuristic approach for MMKP is of great significance. In this study, we attempt to solve MMKP by fusing ant colony optimization (ACO) with Lagrangian relaxation (LR). The algorithm used here follows the algorithmic scheme of max–min ant system for its outstanding performance in solving many other combinatorial optimization problems. The Lagrangian value of the item in MMKP, obtained from LR, is used as the heuristic factor in ACO since it performs best among the six domain-based heuristic factors we define. Furthermore, a novel infeasibility index is proposed for the development of a new repair operator, which converts possibly infeasible solutions into feasible ones. The proposed algorithm was compared with four existing algorithms by applying them to three groups of instances. Computational results demonstrate that the proposed algorithm is capable of producing competitive solutions.     

Robust and efficient ridge-based palmprint matching

During the past decade, many efforts have been made to use palmprints as a biometric modality. However, most of the existing palmprint recognition systems are based on encoding and matching creases, which are not as reliable as ridges. This affects the use of palmprints in large-scale person identification applications where the biometric modality needs to be distinctive as well as insensitive to changes in age and skin conditions. Recently, several ridge-based palmprint matching algorithms have been proposed to fill the gap. Major contributions of these systems include reliable orientation field estimation in the presence of creases and the use of multiple features in matching, while the matching algorithms adopted in these systems simply follow the matching algorithms for fingerprints. However, palmprints differ from fingerprints in several aspects: 1) Palmprints are much larger and thus contain a large number of minutiae, 2) palms are more deformable than fingertips, and 3) the quality and discrimination power of different regions in palmprints vary significantly. As a result, these matchers are unable to appropriately handle the distortion and noise, despite heavy computational cost. Motivated by the matching strategies of human palmprint experts, we developed a novel palmprint recognition system. The main contributions are as follows: 1) Statistics of major features in palmprints are quantitatively studied, 2) a segment-based matching and fusion algorithm is proposed to deal with the skin distortion and the varying discrimination power of different palmprint regions, and 3) to reduce the computational complexity, an orientation field-based registration algorithm is designed for registering the palmprints into the same coordinate system before matching and a cascade filter is built to reject the nonmated gallery palmprints in early stage. The proposed matcher is tested by matching 840 query palmprints against a gallery set of 13,736 palmprints. Experimental results show that the proposed matcher outperforms the existing matchers a lot both in matching accuracy and speed.     

Node trust evaluation in mobile ad hoc networks based on multi-dimensional fuzzy and Markov SCGM(1, 1) model

Due to the nature of distribution and self-organization, mobile ad hoc networks rely on cooperation between nodes to transfer information. One of the key factors to ensure high communication quality is an efficient assessment scheme for risks and trust of choosing next potential cooperative nodes. Trust model, an abstract psychological cognitive process, is one of the most complex concepts in social relationships, involving factors such as assumptions, expectations and behaviors. All of the above make it difficult to quantify and forecast trust accurately. In this paper, based on the theories of fuzzy recognition with feedback, SCGM(1, 1) model and Markov chain, we present a pattern of prediction making. The analysis and experimental computation show that this scheme is efficient in trust prediction for ad hoc networks.     

Modeling and control of discrete event systems using finite state machines with variables and their applications in power grids

Control theories for discrete event systems modeled as finite state machines have been well developed to address various fundamental control issues. However, finite state machine model has long suffered from the problem of state explosion that renders it unsuitable for some practical applications. In an attempt to mitigate the state explosion problem, we propose an efficient representation that appends finite sets of variables to finite state machines in modeling discrete event systems. We also present the control synthesis techniques for such finite state machines with variables (FSMwV). We first present our notion and means of control under this representation. We next present our algorithms for both offline and online synthesis of safety control policies. We then apply these results to the control of electric power grids.