Towards Next Generation Internet Management: CNGI-CERNET2 Experiences

Manageability is an important feature of next generation Internet;management and monitoring of IPv6-based networks are proving a big challenge.While leveraging current IPv4-based SNMP management scheme to IPv6 networks' management need is necessary,it is more urgent to coin a new network management architecture to accommodate the scalability and extensibility requirements of next generation Internet management.The paper proposes a novel network management architecture,IMN(Internet Management Network),whi...     

海量数据多边形布尔运算的区域分割算法

研究了一种大数据量的2维多边形,称为海量数据多边形,其边界由直线段和圆弧段组成,顶点很多,形状复杂。本文设计并实现了海量数据多边形之间的布尔运算算法。首先用区域划分的方法快速求解出两多边形的交点,然后判断各交点的出点、入点性质,最后沿着多边形的边界跟踪,并根据并、交、差的不同要求切换跟踪路线,直到形成封闭的回路。运算结果仍为2维多边形。该算法从实用的角度出发,避开繁琐的数学推理,易于程序实现,在实际应用中显著提高了布尔运算的效率。     

Generating Combinations by Three Basic Operations

We investigate the problem of listing combinations using a special class of operations, prefix shifts. Combinations are represented as bitstrings of O＇s and l＇s, and prefix shifts are the operations of rotating some prefix of a bitstring by one position to left or right. We give a negative answer to an open problem asked by F. Ruskey and A. Williams （Generating combinations by prefix shifts, In Proc. llth Annual International Computing and Combinatorics Conference 2005, LNCS 3595, Springer, 2005, pp.570-576）, that is whether we can generate combinations by only using three very basic prefix shifts on bitstrings, which are transposition of the first two bits and the rotation of the entire bitstring by one position in either direction （i.e., applying the permutations σ2, σn and σn^-1 to the indices of the bitstrings）.     

Symbolic Algorithmic Analysis of Rectangular Hybrid Systems

This paper investigates symbolic algorithmic analysis of rectangular hybrid systems.To deal with the symbolic reachability problem,a restricted constraint system called hybrid zone is formalized for the representation and manipulation of rectangular automata state-spaces.Hybrid zones are proved to be closed over symbolic reachability operations of rectangular hybrid systems.They are also applied to model-checking procedures for verifying some important classes of timed computation tree logic formulas.To ...     

A Trust-Based Approach to Estimating the Confidence of the Software System in Open Environments

Emerging with open environments, the software paradigms, such as open resource coalition and Internetware, present several novel characteristics including user-centric, non-central control, and continual evolution. The goal of obtaining high confidence on such systems is more di?cult to achieve. The general developer-oriented metrics and testing-based methods which are adopted in the traditional measurement for high confidence software seem to be infeasible in the new situation. Firstly, the software develo...     

QoS Requirement Generation and Algorithm Selection for Composite Service Based on Reference Vector

Under SOA (Service-Oriented Architecture), composite service is formed by aggregating multiple component services together in a given workflow. One key criterion of this research topic is QoS composition. Most work on service composition mainly focuses on the algorithms about how to compose services according to assumed QoS, without considering where the required QoS comes from and the selection of user preferred composition algorithm among those with different computational cost and di?erent selection resu...     

ViWoSG: A distributed scene graph of ultramassive distributed virtual environments

An ultra-massive distributed virtual environment generally consists of ultra-massive terrain data and a large quantity of objects and their attribute data, such as 2D/3D geometric models, audio/video, images, vectors, characteristics, etc. In this paper, we propose a novel method for constructing distributed scene graphs with high extensibility. Thismethod can support high concurrent interaction of clients and implement various tasks such as editing, querying, accessing and motion controlling. Some application experiments are performed to demonstrate its efficiency and soundness. Supported by the National Basic Research Program of China (Grant No. 2004CB719403), the National High-Tech Research & Development Program of China (Grant Nos. 2006AA01Z334, 2007AA01Z318, 2009AA01Z324), the National Natural Science Foundation of China (Grant Nos. 60573151, 60703062, 60833007), and the Marine 908-03-01-10 Project     

Haptic rendering for dental training system

Immersion and interaction are two key features of virtual reality systems, which are especially important for medical applications. Based on the requirement of motor skill training in dental surgery, haptic rendering method based on triangle model is investigated in this paper. Multi-rate haptic rendering architecture is proposed to solve the contradiction between fidelity and efficiency requirements. Realtime collision detection algorithm based on spatial partition and time coherence is utilized to enable fast contact determination. Proxy-based collision response algorithm is proposed to compute surface contact point. Cutting force model based on piecewise contact transition model is proposed for dental drilling simulation during tooth preparation. Velocity-driven levels of detail haptic rendering algorithm is proposed to maintain high update rate for complex scenes with a large number of triangles. Hapticvisual collocated dental training prototype is established using half-mirror solution. Typical dental operations have been realized including dental caries exploration, detection of boundary within dental cross-section plane, and dental drilling during tooth preparation. The haptic rendering method is a fundamental technology to improve immersion and interaction of virtual reality training systems, which is useful not only in dental training, but also in other surgical training systems. Supported by National Natural Science Foundation of China (Grant Nos. 60605027, 50575011), National High-Tech Research & Development Program of China (Grant No. 2007AA01Z310)     

Demand-Driven Memory Leak Detection Based on Flow- and Context-Sensitive Pointer Analysis

We present a demand-driven approach to memory leak detection algorithm based on flow- and context-sensitive pointer analysis. The detection algorithm firstly assumes the presence of a memory leak at some program point and then runs a backward analysis to see if this assumption can be disproved. Our algorithm computes the memory abstraction of programs based on points-to graph resulting from flow- and context-sensitive pointer analysis. We have implemented the algorithm in the SUIF2 compiler infrastructure and used the implementation to analyze a set of C benchmark programs. The experimental results show that the approach has better precision with satisfied scalability as expected. This work is supported by the National Natural Science Foundation of China under Grant Nos. 60725206, 60673118, and 90612009, the National High-Tech Research and Development 863 Program of China under Grant No. 2006AA01Z429, the National Basic Research 973 Program of China under Grant No. 2005CB321802, the Program for New Century Excellent Talents in University under Grant No. NCET-04-0996, and the Hunan Natural Science Foundation under Grant No. 07JJ1011.     

Runtime Monitoring CompositeWeb Services Through Stateful Aspect Extension

The execution of composite Web services with WS-BPEL relies on externally autonomous Web services. This implies the need to constantly monitor the running behavior of the involved parties. Moreover, monitoring the execution of composite Web services for particular patterns is critical to enhance the reliability of the processes. In this paper, we propose an aspect-oriented framework as a solution to provide monitoring and recovery support for composite Web services. In particular, this framework includes 1) a stateful aspect based template, where history-based pointcut specifies patterns of interest cannot be violated within a range, while advice specifies the associated recovery action; 2) a tool support for runtime monitoring and recovery based on aspect-oriented execution environment. Our experiments indicate that the proposed monitoring approach incurs minimal overhead and is efficient. This work is supported by the National Natural Science Foundation of China under Grant Nos. 60673112, 90718033, the National Basic Research 973 Program of China under Grant No. 2009CB320704, and the High-Tech Research and Development 863 Program of China under Grand Nos. 2006AA01Z19B, 2007AA010301.     

Boolean operations on general planar polygons

Computing boolean operations between general planar polygons is one of the fundamental problems in geometric and solid modeling. In this work we present a new algorithm to calculate intersection, union and difference, valid for general planar polygons (manifold and non-manifold, with and without holes), based on a formal representation system. This formal model is based on the concept of simplicial chain, developed by Feito and Rivero (Computers & Graphics 22(5) (1998)). Using algebraic operations between simplicial chains we can obtain any general polygon and the Boolean operations between them. The fact of that our algorithm is based on simplicial chains and their operations, reduces the study of special cases, and allows us to develop a robust and efficient algorithm to calculate the intersection between general polygons.     

Rigidity Constraints for Large Mesh Deformation

It is a challenging problem of surface-based deformation to avoid apparent volumetric distortions around largely deformed areas. In this paper, we propose a new rigidity constraint for gradient domain mesh deformation to address this problem. Intuitively the proposed constraint can be regarded as several small cubes defined by the mesh vertices through mean value coordinates. The user interactively specifies the cubes in the regions which are prone to volumetric distortions, and the rigidity constraints ...     

Removing local irregularities of triangular meshes with highlight line models

The highlight line model is a powerful tool in assessing the quality of a surface. It increases the flexibility of an interactive design environment. In this paper, a method to generate a highlight line model on an arbitrary triangular mesh is presented. Based on the highlight line model, a technique to remove local shape irregularities of a triangular mesh is then presented. The shape modification is done by solving a minimization problem and performing an iterative procedure. The new technique improves not only the shape quality of the mesh surface, but also the shape of the highlight line model. It provides an intuitive and yet suitable method for locally optimizing the shape of a triangular mesh. Supported by National Science Foundation of China (Grant Nos. 60533070, 60625202), National Basic Research Program of China (Grant No. 2004CB719400), National High-Tech Research & Development Program of China (Grant No. 2007AA040401), Fok Ying Tung Education Foundation (Grant No. 111070), National Science Foundation of USA (Grant Nos. DMI-0422126, DMS-0310645), and Kentucky Science & Technology Corporation (Grant No. COMM-Fund-712)     

Recent advances on virtual human synthesis

Virtual human is a digital representation of the geometric and behavioral property of human beings in the virtual environment generated by computer. The research goal of virtual human synthesis is to generate realistic human bodymodels and natural human motion behavior. This paper introduces the development of the related researches on these two topics, and some progresses on example based human modeling and motion synthesis, and their applications in Chinese sign language teaching, computeraided sports training and public safety problem studying. Finally, some hot research topics in virtual human synthesis are presented. Supported partially by the National High-Tech Research & Development Program of China (Grant Nos. 2006AA01Z336, 2007AA01Z320), and the National Natural Science Foundation of China (Grant No. 60533070)     

Cryptography on elliptic curves over <Emphasis Type="Italic">p</Emphasis>-adic number fields

In this paper we introduce a cryptosystem based on the quotient groups of the group of rational points of an elliptic curve defined over p-adic number field. Some additional parameters are taken in this system, which have an advantage in performing point multiplication while keeping the security of ECC over finite fields. We give a method to select generators of the cryptographic groups, and give a way to represent the elements of the quotient groups with finitely bounded storage by establishing a bijection between these elements and their approximate coordinates. The addition formula under this representation is also presented.     

Leakage Current Optimization Techniques During Test Based on Don t Care Bits Assignment

It is a well-known fact that test power consumption may exceed that during functional operation. Leakage power dissipation caused by leakage current in Complementary Metal-Oxide-Semiconductor （CMOS） circuits during test has become a significant part of the total power dissipation. Hence, it is important to reduce leakage power to prolong battery life in portable systems which employ periodic self-test, to increase test reliability and to reduce test cost. This paper analyzes leakage current and presents a kind of leakage current simulator based on the transistor stacking effect. Using it, we propose techniques based on don＇t care bits （denoted by Xs） in test vectors to optimize leakage current in integrated circuit （IC） test by genetic algorithm. The techniques identify a set of don＇t care inputs in given test vectors and reassign specified logic values to the X inputs by the genetic algorithm to get minimum leakage vector （MLV）. Experimental results indicate that the techniques can effectually optimize leakage current of combinational circuits and sequential circuits during test while maintaining high fault coverage,     

Parallel Error Detection for Leading Zero Anticipation

The algorithm and its implementation of the leading zero anticipation （LZA） are very vital for the performance of a high-speed floating-point adder in today＇s state of art microprocessor design. Unfortunately, in predicting ＂shift amount＂ by a conventional LZA design, the result could be off by one position. This paper presents a novel parallel error detection algorithm for a general-case LZA. The proposed approach enables parallel execution of conventional LZA and its error detection, so that the error-indicatlon signal can be generated earlier in the stage of normalization, thus reducing the critical path and improving overall performance. The circuit implementation of this algorithm also shows its advantages of area and power compared with other previous work.     

Modeling plants with sensor data

Sensor data, typically images and laser data, are essential to modeling real plants. However, due to the complex geometry of the plants, the measurement data are generally limited, thereby bringing great difficulties in classifying and constructing plant organs, comprising leaves and branches. The paper presents an approach to modeling plants with the sensor data by detecting reliable sharp features, i.e. the leaf apexes of the plants with leaves and the branch tips of the plants without leaves, on volumes recovered from the raw data. The extracted features provide good estimations of correct positions of the organs. Thereafter, the leaves are reconstructed separately by simply fitting and optimizing a generic leaf model. One advantage of the method is that it involves limited manual intervention. For plants without leaves, we develop an efficient strategy for decomposition-based skeletonization by using the tip features to reconstruct the 3D models from noisy laser data. Experiments show that the sharp feature detection algorithm is effective, and the proposed plant modeling approach is competent in constructing realistic models with sensor data. Supported in part by the National Basic Research Program of China (Grant No. 2004CB318000), the National High-Tech Research & Development Program of China (Grant Nos. 2006AA01Z301, 2006AA01Z302, 2007AA01Z336), Key Grant Project of Chinese Ministry of Education (Grant No. 103001)     

Test-Data Generation Guided by Static Defect Detection

Software testing is an important technique to assure the quality of software systems, especially high-confidence systems. To automate the process of software testing, many automatic test-data generation techniques have been proposed. To generate e?ective test data, we propose a test-data generation technique guided by static defect detection in this paper. Using static defect detection analysis, our approach first identifies a set of suspicious statements which are likely to contain faults, then generates t...     

An Improved Markov Model for IEEE 802.15.4 Slotted CSMA/CA Mechanism

IEEE 802.15.4 protocol is proposed to meet the low latency and energy consumption needs in low-rate wireless applications,however,few analytical models are tractable enough for comprehensive evaluation of the protocol.To evaluate the IEEE 802.15.4 slotted CSMA/CA channel access mechanism in this paper,we propose a practical and accurate discrete Markov chain model,which can dynamically represent different network loads.By computing the steady-state distribution probability of the Markov chain,we obtain a...